US20090211864A1 - Friction clutch - Google Patents
Friction clutch Download PDFInfo
- Publication number
- US20090211864A1 US20090211864A1 US12/392,323 US39232309A US2009211864A1 US 20090211864 A1 US20090211864 A1 US 20090211864A1 US 39232309 A US39232309 A US 39232309A US 2009211864 A1 US2009211864 A1 US 2009211864A1
- Authority
- US
- United States
- Prior art keywords
- clutch
- circlip
- retainer
- plate
- friction clutch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000002093 peripheral effect Effects 0.000 claims abstract description 3
- 230000007246 mechanism Effects 0.000 claims description 27
- 230000005540 biological transmission Effects 0.000 description 36
- 230000004048 modification Effects 0.000 description 12
- 238000012986 modification Methods 0.000 description 12
- 230000008901 benefit Effects 0.000 description 5
- 239000000470 constituent Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 3
- 125000006850 spacer group Chemical group 0.000 description 3
- 238000010586 diagram Methods 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D13/00—Friction clutches
- F16D13/58—Details
- F16D13/583—Diaphragm-springs, e.g. Belleville
- F16D13/585—Arrangements or details relating to the mounting or support of the diaphragm on the clutch on the clutch cover or the pressure plate
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D13/00—Friction clutches
- F16D13/04—Friction clutches with means for actuating or keeping engaged by a force derived at least partially from one of the shafts to be connected
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D13/00—Friction clutches
- F16D13/22—Friction clutches with axially-movable clutching members
- F16D13/38—Friction clutches with axially-movable clutching members with flat clutching surfaces, e.g. discs
- F16D13/52—Clutches with multiple lamellae ; Clutches in which three or more axially moveable members are fixed alternately to the shafts to be coupled and are pressed from one side towards an axially-located member
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D43/00—Automatic clutches
- F16D43/02—Automatic clutches actuated entirely mechanically
- F16D43/04—Automatic clutches actuated entirely mechanically controlled by angular speed
- F16D43/06—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating axially a movable pressure ring or the like
- F16D43/08—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating axially a movable pressure ring or the like the pressure ring actuating friction plates, cones or similar axially-movable friction surfaces
- F16D43/12—Automatic clutches actuated entirely mechanically controlled by angular speed with centrifugal masses actuating axially a movable pressure ring or the like the pressure ring actuating friction plates, cones or similar axially-movable friction surfaces the centrifugal masses acting on, or forming a part of, an actuating mechanism by which the pressure ring can also be actuated independently of the masses
Definitions
- the present invention relates to a friction clutch.
- the friction clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177 is a multiple-disc automatic centrifugal friction clutch used in a motorcycle.
- the weight roller receives a centrifugal force by rotation of the clutch shaft and moves radially outward of the clutch shaft.
- the centrifugal force of the weight roller is converted into a pressing force in the thrust direction of the pressure plate due to the internal structure of the clutch.
- the drive plate and the driven plate are pressed by the pressing force of the pressure plate.
- the drive plate and the driven plate which are pressed transmit a drive force of an engine of the motorcycle to a rear wheel.
- a position at which the circlip is fitted into the clutch housing is one end side of the clutch housing in the axial direction of the clutch shaft.
- the circlip restricts positions of the constituent elements of the clutch housing such as the plate, the centrifugal weight, and the clutch plate spring related to rotation of the clutch shaft in the axial direction of the clutch shaft by being fitted into the clutch housing. Further, the circlip receives a reaction force to the biasing force of the clutch plate spring and prevents detachment of such plates as the drive plate and the driven plate from the clutch housing by being fitted into the clutch housing.
- the clutch serving as a transmission mechanism transmitting the drive force of the engine is configured, for example, so that the diameters of the plates including the friction plate and the clutch plate are increased so as to correspond to the configuration of the high-power engine.
- the diameter of the circlip preventing detachment of such plates as the friction plate and the clutch plate is also made larger.
- the present invention has been devised in view of the foregoing problems, and it is an object of the present invention to prevent a retaining ring (such as a circlip) from detaching from a clutch housing.
- a retaining ring such as a circlip
- the inventor of the present application has exerted utmost efforts as well as conducted studies to attain the foregoing object and has discovered that a main cause for detachment of the circlip is a radially inward deformation of the circlip.
- the circlip typically has a substantially annular shape in which an outer circumferential side of the circlip is fitted into the clutch housing. Consequently, deformation of the circlip tends to occur on the inner circumferential side rather than on the outer circumferential side. This deformation is considered to result from the fact that the circlip has the substantially annular shape and, more particularly, has a so-called C shape with a slit formed in a portion of the circlip.
- a C-shaped circlip 85 is shown, for example, in FIGS. 5 a and 5 b.
- Circlip 85 has a slit or notched portion 85 b.
- the diameter of the circlip is temporarily reduced so as to be smaller than an inner hull of the clutch housing.
- the diameter of the circlip is reduced, for example, by applying an external compressing force to the circlip so that the terminal ends of circlip 85 come into contact with each other.
- the circlip fitted into the clutch housing generates an expanding force extending along the circlip diameter (hereinafter, referred to as “extension force”). This extension force enables the inner hull of the clutch housing and the outer circumference of this circlip to contact each other.
- the clutch employing the circlip shown in FIGS. 5 a and 5 b often includes a clutch spring (clutch plate spring).
- circlip 85 is fitted into the clutch housing, thereby receiving a reaction force to the biasing force of the clutch spring.
- the reaction force to the biasing force of the clutch spring causes the front and rear terminal end surfaces ( FIG. 5 a ) of the circlip to make contact with the clutch housing.
- the contact of the circlip 85 with the clutch housing allows the circlip 85 and the clutch housing to generate a frictional force in a portion in which the circlip 85 and the clutch housing contact each other.
- the clutch including the circlip 85 is a centrifugal clutch similar to the clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177
- the magnitude of the reaction force to the biasing force of the clutch spring varies according to the change in rotational speed of the clutch shaft.
- the weight roller receives the centrifugal force and moves radially outward relative to the clutch shaft by rotation of the clutch shaft.
- the centrifugal force of the weight roller is converted into a pressing force in the thrust direction of the pressure plate by the internal structure of the clutch.
- the drive plate and the driven plate are pressed by the pressing force of the pressure plate.
- the clutch includes the clutch plate spring as means for generating the pressing force. If the rotational speed of the clutch shaft is higher, the clutch plate spring needs a greater biasing force for pressing the drive plate and the driven plate. In this way, if the biasing force of the clutch disc spring is of relatively high magnitude, the circlip receives a greater reaction force to the biasing force of the clutch plate spring. If the reaction force to the biasing force of the clutch plate spring is greater, a greater frictional force is generated in the portion of the circlip that contacts the clutch housing.
- the outer circumferential side of the circlip contacts the inner hull of clutch housing by the extension force which is directed radially outward of the circlip. Further, the circlip receives the reaction force to the biasing force of the clutch spring.
- the front and rear surfaces (front and rear surfaces in FIG. 5 a ) of the circlip make contact with the clutch housing due to the reaction force of the clutch housing to the biasing force. Due to this, a frictional force is generated in the portion of the circlip that contacts the clutch housing.
- the frictional force applied to the portion of the circlip that contacts the clutch housing is not uniform on the entire circlip. Namely, the force due to friction with the clutch housing differs in magnitude or the like among the mass points on the circlip.
- the circlip is considered to undergo deformation.
- the outer circumferential side of the circlip can make contact with the inner hull of the clutch housing. Due to this, it is considered that the inner circumferential side of the circlip deforms more easily than the outer circumferential side thereof.
- the invention is directed to a friction clutch.
- the friction clutch includes a main shaft driven to rotate by the engine, a clutch housing including a first plate, and rotating along the main shaft, a clutch boss including a second plate opposed to the first plate in a predetermined direction, a pressure plate causing the first plate and the second plate to contact each other by moving in the predetermined direction, a clutch spring arranged on the opposite side of the pressure plate relative to the first and second plates in the predetermined direction, the clutch spring having a biasing force in a direction of causing the first plate and the second plate to contact each other to the pressure plate, a retainer formed into a substantially circular shape and receiving a reaction force to the biasing force of the clutch spring by supporting one end of the clutch spring opposite to the pressure plate, and a retaining ring having a substantially circular shape, the retaining ring having
- the invention is directed at a vehicle, such as a motorcycle, including a frictional clutch as described herein.
- FIG. 1 is a side view of a motorcycle.
- FIG. 2 is a schematic diagram illustrating the main components of a power unit of the motorcycle of FIG. 1 .
- FIG. 3 is a cross-sectional view of a clutch of the motorcycle of FIG. 1 .
- FIG. 4 is a partial perspective view of a clutch housing viewed obliquely from the top.
- FIG. 5 a is a front view of a circlip according to a first embodiment.
- FIG. 5 b is a cross-sectional view of the circlip of FIG. 5 a.
- FIG. 6 a is a front view of a retainer according to the first embodiment.
- FIG. 6 b is a cross-sectional view of the retainer of FIG. 6 a.
- FIG. 7 is a front view showing a state in which the retainer and circlip are attached to a clutch housing according to the first embodiment.
- FIG. 8 is an enlarged partial cross-sectional view of a clutch utilizing the retainer and circlip of FIG. 7 according to the first embodiment.
- FIG. 9 a is a front view of a retainer according to a first modification of the first embodiment.
- FIG. 9 b is a cross-sectional view of the retainer of FIG. 9 a.
- FIG. 10 is a front view showing a state in which the retainer of FIG. 9 a and a circlip are attached to a clutch housing according to the first modification.
- FIG. 11 is an enlarged partial cross-sectional view of a clutch according to the first modification.
- FIG. 12 a is a front view of a retainer according to a second modification of the first embodiment.
- FIG. 12 b is a cross-sectional view of the retainer of FIG. 12 a.
- FIG. 13 is a front view showing a state in which the retainer of FIG. 12 a and a circlip are attached to a clutch housing according to the second modification.
- FIG. 14 is an enlarged partial cross-sectional view of a clutch utilizing the retainer of FIG. 12 .
- FIG. 15 a is front view of a retainer according to a second embodiment.
- FIG. 15 b is a cross-sectional view of the retainer of FIG. 15 a.
- FIG. 16 a is front view of a circlip according to the second embodiment.
- FIG. 16 b is a cross-sectional view of the circlip of FIG. 16 a.
- FIG. 17 is a front view showing a state in which the retainer and circlip of FIGS. 15 a and 16 b, respectively, are attached to a clutch housing.
- FIG. 18 is an enlarged partial cross-sectional view of a clutch utilizing the retainer and circlip of FIG. 17 .
- the diameter of the circlip preventing detachment of such plates as the friction plate and the clutch plate is also made larger. Furthermore, since it is necessary to increase the pressing force of the pressure plate (which presses the friction plate and the clutch plate), the biasing force of the clutch spring urging this pressing force is also increased. If the biasing force of the clutch spring is greater, the load imposed on the circlip receiving the reaction force to the biasing force of the clutch spring becomes heavier.
- the centrifugal force is generated at respective mass points on the circlip when the clutch shaft rotates during driving of the engine.
- a greater centrifugal force according to the mass of the circlip is generated in a larger-diameter circlip than in a smaller-diameter circlip.
- a greater centrifugal force is generated than that generated when the clutch shaft rotates at low rotational speed.
- the length of a circular arc on the outer circumferential side of the circlip which is in contact with the inner hull of the clutch housing would be a function of the diameter of the circlip. Due to this, if the circlip has a larger diameter, the contact area between the inner hull of the clutch housing and the outer circumferential side of the circlip is also larger. Therefore, the frictional force generated between the outer circumferential side of the larger-diameter circlip and the inner hull of the clutch housing varies in accordance with the size of the contact area.
- the detachment of the circlip is conspicuously recognized when the drive force is instantaneously recovered from driving of the engine at high engine speed.
- the detachment of the circlip is a phenomenon that occurs when a throttle valve used to drive the engine is closed to a minimum opening position instantaneously from a maximum opening position. Due to this, the inventor of the present application has considered, as a cause for the detachment of the circlip, a sudden drop in the rotational speed of the clutch shaft and a sudden drop in the centrifugal force on the entire circlip, accordingly. Further, when the centrifugal force of the entire circlip suddenly drops, it is considered that the frictional force between the circlip and the clutch housing also suddenly falls.
- the circlip for which the frictional force between the circlip and the clutch housing falls is considered to rotate relative to the clutch housing.
- the rotation of the circlip relative to the clutch housing is considered to result from sliding of the circlip having an inertial force generated by the rotation of the clutch shaft on the clutch housing having the reduced frictional force.
- the frictional force differs among the mass points on the circlip in magnitude or the like. Due to this, during the relative rotation of the circlip to the clutch housing, it is considered that the inertial force is greater than the frictional force at some mass points and that the frictional force is greater than the inertial force at other mass points. Therefore, the inventor of the present application has estimated that the circlip deforms according to changes in the magnitude or the like of the frictional force at respective mass points on the circular portion of the circlip.
- the shape of the circlip is not limited to a specific shape.
- the circular C shape (see FIG. 5 ) is popular and normally adopted as the shape of the circlip. Due to this, the inventor of the present application has used a C-shaped circlip in a clutch without exception.
- the circlip 85 includes slit or notched portion 85 b. Since the outer circumferential side of the circlip 85 is fitted into the clutch housing, the deformation of the outer circumferential side of the circlip 85 is less likely to occur. However, the inner circumferential side of the circlip 85 is considered to deform more easily than the outer circumferential side thereof.
- the circlip 85 If the inner circumferential side of the circlip 85 deforms radially inward, the circlip 85 often temporarily detaches from the portion (clutch housing) held in the clutch instantaneously. Even if a detached portion is only a part of the circlip 85 , the circlip 85 instantaneously detaches from the clutch housing due to the significant biasing force of the clutch spring.
- an interior of the clutch is configured to suppress the radially inward deformation of the circlip so as to be able to prevent the detachment of the circlip from the clutch housing.
- a vehicle including a centrifugal clutch according to embodiments of the present invention will be described hereinafter in detail with reference to the drawings. It is to be noted, however, that the vehicle described below is only an example of a preferred mode for carrying out the present invention.
- the vehicle according to the present invention is not limited to a motorcycle 1 described below.
- the term “motorcycle” refers to a vehicle of the type whose vehicle body is designed to be leaned when making a turn. Accordingly, the term “motorcycle” as used herein is not limited to a vehicle including two wheels but may also include vehicles including three or more wheels.
- FIG. 1 is a left side view of a motorcycle 1 according to an embodiment.
- longitudinal and crosswise directions are directions viewed from a passenger seated on a seat 16 to be described later.
- motorcycle 1 includes a vehicle body 7 , a front wheel 14 provided at a front section of the vehicle body 7 , and a rear wheel 19 provided at a rear section of the vehicle body 7 .
- the vehicle body 7 includes a vehicle body frame 10 .
- the vehicle body frame 10 includes a head pipe 11 .
- a handlebar 12 is provided to an upper end portion of the head pipe 11 .
- the front wheel 14 is rotatably mounted to a lower end of the head pipe 11 via a front fork 13 .
- a power unit 3 is suspended from the vehicle body frame 10 .
- a vehicle body cover 15 is attached to the vehicle body frame 10 .
- a seat 16 is disposed so as to extend rearward from a substantially central position of the vehicle body 7 to the rear side thereof in the front-rear direction.
- a fuel tank 17 is disposed in front of the seat 16 .
- a rear arm 18 is pivotally supported on the vehicle body frame 10 .
- the rear wheel 19 which serves as a drive wheel, is rotatably attached to a rear end of the rear arm 18 .
- the rear wheel 19 is connected to an engine 4 (see FIG. 2 ) through a power transmission mechanism (not shown). The drive force of the engine 4 is thereby transmitted to the rear wheel 19 so that the rear wheel 19 rotates.
- An accelerator grip (not shown) is provided on the right side of the handlebar 12 .
- a left grip 29 is provided on the left side of the handlebar 12 .
- a clutch lever 24 that is operated to engage/disengage friction clutch 2 (see FIG. 2 ), which is described later, is provided in front of the left grip 29 of the handlebar 12 .
- Footrests 20 L are provided on each side of the vehicle body 7 at a central portion thereof in the front-rear direction.
- a shift pedal 27 is operated to change the transmission gear ratio of a transmission 5 (see FIG. 2 ), which will be described later, is provided on the left side of the vehicle body 7 at a position slightly in front of the left footrest 20 L.
- a side stand 28 is provided on the left side of the vehicle body 7 at a position below the shift pedal 27 and the footrest 20 L.
- the power unit 3 includes the engine 4 , the transmission 5 , and the clutch 2 .
- the type of the engine 4 is not limited to a particular type of engine, a water-cooled, four-cycle, parallel four-cylinder engine is used as the engine 4 .
- the engine 4 includes four cylinders, a piston reciprocating in each of the respective cylinders, and a crankshaft 32 connected to each of the pistons via a connecting rod.
- the crankshaft 32 extends in a vehicle width direction.
- Reference numeral 31 denotes a crankcase.
- the crankshaft 32 is connected to the transmission 5 via the clutch 2 .
- the transmission 5 includes a main shaft 33 , a drive shaft 23 , and a gear selection mechanism 36 .
- the main shaft 33 is connected to the crankshaft 32 via the clutch 2 .
- the main shaft 33 and the drive shaft 23 are disposed parallel to the crankshaft 32 , respectively.
- a plurality of multi-stage transmission gears 34 are mounted on the main shaft 33 .
- a plurality of transmission gears 35 corresponding to the multi-stage transmission gears 34 are mounted on the drive shaft 23 .
- the multi-stage transmission gears 34 and the plurality of transmission gears 35 are disposed so that only one pair of selected gears is engaged with each other.
- Either the transmission gears 34 excluding the selected transmission gear 34 or the transmission gears 35 excluding the selected transmission gear 35 are rotatable with respect to the main shaft 33 or the drive shaft 23 or both. That is, at least one of the non-selected transmission gears 34 or the non-selected transmission gears 35 run idle with respect to the main shaft 33 or the drive shaft 23 . In other words, rotation is transmitted between the main shaft 33 and the drive shaft 23 only via the selected transmission gear 34 and the selected transmission gear 35 which are engaged with each other.
- the transmission gears 34 and 35 are selected by the gear selection mechanism 36 .
- the transmission gears 34 and 35 are selected by a shift cam 37 of the gear selection mechanism 36 .
- a plurality of cam grooves 37 a are formed on an outer circumferential surface of the shift cam 37 .
- a shift fork 38 is engaged with each cam groove 37 a.
- Each shift fork 38 is engaged with predetermined transmission gears 34 and 35 of the main shaft 33 and the drive shaft 23 , respectively.
- As the shift cam 37 rotates, a plurality of shift forks 38 are guided in their respective cam grooves 37 a to move in a direction of the main shaft 33 , so that gears to be engaged with each other are selected from among the transmission gears 34 and 35 .
- a power transmission mechanism which connects the engine 4 and the rear wheel 19 comprises the clutch 2 , the transmission 5 and a transmission mechanism (not shown) such as a chain.
- the clutch 2 is constituted by a multiple-disc friction clutch. Further, the clutch 2 is a centrifugal clutch that is automatically engaged or disengaged at the time of starting or stopping motorcycle 1 and which is optionally engaged or disengaged through the operation of the clutch lever 24 by a rider. A configuration of the clutch 2 will be described in detail.
- the clutch 2 includes a clutch housing 46 .
- the main shaft 33 extends through the clutch housing 46 .
- the clutch housing 46 includes a housing body 46 c.
- the housing body 46 c is formed in a substantially cylindrical form that is closed at one end by a bottom 46 a.
- the main shaft 33 also extends through the bottom 46 a of the housing body 46 c.
- a plurality of pairs of arms 46 d are provided on the housing body 46 c. Each arm 46 d extends outward from the bottom 46 a toward the outside in a vehicle width direction. Further, a circlip groove 46 e is provided in each arm 46 d on the inner periphery of the arm 46 d as described later and as shown in reference to FIG. 4 .
- the vehicle width direction may also be referred to as a left-right direction.
- the clutch 2 is disposed on the right side of the main shaft 33 such that the “outside” in the vehicle width direction corresponds to the right side, and “inside” in the vehicle width direction corresponds to the left side. Therefore, the “outside” and the “inside” in the vehicle width direction will be referred to simply as the “right side” and the “left side,” respectively.
- a scissor gear 45 is attached to the clutch housing 46 .
- the scissor gear 45 includes two gears 45 a and 45 b, a spring 49 , and two plates 51 and 52 .
- the gear 45 a and the gear 45 b are located between the two plates 51 and 52 .
- the two plates 51 and 52 are fixed to each other with fasteners, such as rivets and screws, in the axial direction of the main shaft 33 . Therefore, the two gears 45 a and 45 b are substantially fixed to each other with respect to the axial direction of the main shaft 33 . Meanwhile, the gears 45 a and 45 b are rotatable relative to each other with respect to the rotational direction.
- the gears 45 a and 45 b have the same number of teeth.
- the gears 45 a and 45 b are arranged so that their teeth are alternately located in a circumferential direction.
- the spring 49 is provided between the gears 45 a and 45 b. Therefore, torsional torque is applied to the gears 45 a and 45 b by the spring 49 . Thus, the torque variations caused by the engine 4 can be absorbed.
- the gear 45 a of the scissor gear 45 is engaged with a gear 32 a ( FIG. 2 ) of the crankshaft 32 .
- the gear 45 a (of the scissor gear 45 ) is fixed to the bottom 46 a of the clutch housing 46 so as to be unrotatable relative thereto. With such a configuration, the gear 45 a of the scissor gear 45 and the clutch housing 46 integrally rotate following the rotation of the crankshaft 32 .
- a needle bearing 53 and a spacer 54 which is nonrotatably fixed to the main shaft 33 , are disposed between the scissor gear 45 and the main shaft 33 .
- the needle bearing 53 enables the scissor gear 45 to be rotatable with respect to main shaft 33 . In other words, rotation of the scissor gear 45 is not transmitted directly to the main shaft 33 .
- a clutch boss 48 is nonrotatably fixed to the main shaft 33 by a nut 67 . That is, the clutch boss 48 rotates together with the main shaft 33 .
- a thrust bearing 63 is disposed between the clutch boss 48 and the scissor gear 45 .
- the scissor gear 45 , the needle bearing 53 , and the spacer 54 are regulated so that they do not come closer than a predetermined distance to the clutch boss 48 . In other words, movement of the scissor gear 45 , the needle bearing 53 , and the spacer 54 toward the clutch boss 48 in the axial direction of the main shaft 33 .
- a plurality of friction plates 64 are arranged inside the clutch housing 46 .
- Each friction plate 64 is fixed to the clutch housing 46 with respect to the rotational direction of the main shaft 33 .
- the plurality of friction plates 64 rotate together with the clutch housing 46 .
- Each friction plate 64 is displaceable in the axial direction of the main shaft 33 .
- the distance between two adjacent friction plates 64 is variable.
- the plurality of friction plates 64 are arranged in the axial direction of the main shaft 33 .
- a clutch plate 65 is disposed between adjacent friction plates 64 .
- the clutch plate 65 is opposed to the adjacent friction plates 64 .
- Each clutch plate 65 is fixed to the clutch boss 48 with respect to the rotational direction of the main shaft 33 .
- the plurality of clutch plates 65 rotates together with the clutch boss 48 .
- each clutch plate 65 is displaceable with respect to the axial direction of the main shaft 33 .
- the distance between mutually adjacent clutch plates 65 is variable.
- a plate group 66 comprises the plurality of friction plates 64 and the plurality of clutch plates 65 , as shown in FIG. 3 .
- a pressure plate 77 is arranged on the right side of the main shaft 33 , as depicted in reference to FIG. 3 .
- the pressure plate 77 is formed into a substantially disc shape.
- a sub clutch 100 is provided at a central portion of the pressure plate 77 .
- a radially outward end of the pressure plate 77 is engaged with arms 46 d. Therefore, the pressure plate 77 is not rotatable with respect to the clutch housing 46 but it rotates together with the clutch housing 46 .
- a pressing portion 77 b that projects toward the plate group 66 is formed on the pressure plate 77 at an outer section thereof, as illustrated in FIG. 3 .
- the pressing portion 77 b faces the rightmost friction plate 64 in the plate group 66 .
- the pressing portion 77 b pushes the plate group 66 leftward.
- the friction plates 64 and the clutch plates 65 in the plate group 66 are press-contacted into frictional contact with each other.
- a plurality of cam surfaces 81 are formed on a surface opposite to the plate group 66 in the radially outward portion of the pressure plate 77 .
- the plurality of cam surfaces 81 and the plurality of roller weights 41 are provided along the circumferential direction.
- the plurality of cam surfaces 81 are arranged radially about the longitudinal axis of the main shaft 33 .
- Each cam surface 81 is inclined rightward as it moves outward in the radial direction.
- a roller retainer 78 is disposed on the right side of the pressure plate 77 .
- the roller retainer 78 is formed into a ring band shape when viewed from the axial direction of the main shaft 33 .
- the roller retainer 78 is opposed to the cam surface 81 of the pressure plate 77 . Therefore, a space 82 that becomes narrower in the radial direction of the main shaft 33 is formed by each cam surfaces 81 and the roller retainer 78 .
- roller retainer 78 Similar to the pressure plate 77 , a radially outward end of the roller retainer 78 is engaged with the plurality of arms 46 d. The roller retainer 78 is thereby nonrotatable about the clutch housing 46 . In other words, the roller retainer 78 rotates together with the clutch housing 46 . Meanwhile, the roller retainer 78 is displaceable with respect to the clutch housing 46 in the axial direction of the main shaft 33 .
- the roller retainer 78 is urged leftward by a disc spring 83 which serves as a biasing member.
- the roller retainer 78 is urged toward the plate group 66 by disc spring 83 .
- the roller retainer 78 and the disc spring 83 constitute an abutment member 70 that presses the roller weights 41 toward the cam surfaces 81 .
- a roller weight 41 is provided in each of a plurality of spaces 82 .
- the roller weight 41 revolves following the rotation of the clutch housing 46 and moves on the cam surface 81 radially outward by means of a centrifugal force generated during the revolution.
- the roller weight 41 receives a biasing force from abutment member 70 and presses the pressure plate 77 toward the plate group ( 66 ) side.
- the clutch 2 includes a sub-clutch 100 .
- the sub-clutch 100 includes a friction plate 101 , a first pressing plate 102 that faces a left surface (hereinafter, “first friction surface”) 101 a of the friction plate 101 , and a second pressing plate 103 that faces a right surface (hereinafter, “second friction surface”) 101 b of the friction plate 101 .
- the clutch 2 includes a clutch release mechanism 86 ( FIG. 3 ).
- the clutch release mechanism 86 forcibly releases a pressed-contact state of the plate group 66 in response to the operation of the clutch lever 24 by a rider.
- the clutch release mechanism 86 enables the clutch 2 to be disengaged by the manual operation of a rider of the motorcycle 1 .
- the clutch 2 includes a power-assist mechanism 200 .
- the power-assist mechanism 200 converts part of the torque of the pressure plate 77 into a force for disengaging the clutch 2 so as to reduce the force required to disengage the clutch 2 .
- the power-assist mechanism 200 comprises a so-called ball cam.
- the power-assist mechanism 200 includes a slide shaft 201 fixed to the second pressing plate 103 , a first cam plate 202 , a second cam plate 203 , a ball plate 204 , and a coil spring 205 that biases the second cam plate 203 in a direction which separates the second cam plate 203 from the first cam plate 202 .
- a support plate 250 that supports the coil spring 205 by abutting a right portion of the coil spring 205 is fixed onto a terminal side of the slide shaft 201 .
- the power-assist mechanism 200 is not limited to the ball cam structure and may be configured as any other appropriate structure as long as the power-assist mechanism is configured to reduce the force required to disengage the clutch 2 .
- a retainer 84 is arranged on a right end of the housing body 46 c. As shown in FIG. 6 a, the retainer 84 is shaped to be fitted into an outer hull of the housing body 46 c. In the present embodiment, the clutch housing 46 is cylindrical. Due to this, the retainer 84 is ring-shaped. The retainer 84 includes mount holes 84 a. The arms 46 d (see FIGS. 3 and 4 ) of the housing body 46 c are fitted into the mount holes 84 a.
- a stopper 84 c ( FIGS. 6 a - 6 b ) is provided on the retainer 84 along the inner circumference of the retainer 84 .
- the stopper 84 c is shaped so that the inner circumference of the circular portion of the retainer 84 includes a shoulder protruding from the front surface as shown in reference to FIG. 6 b and FIG. 8 (e.g., the left direction in FIG. 6 b and the right direction in FIG. 8 ).
- FIG. 5 a is a front plan view of circlip 85 according to the present embodiment.
- the circlip 85 has a notched ring shape configured to lock the retainer 84 onto the housing body 46 c.
- the circlip 85 includes slit or notched portion 85 b as depicted in reference to FIG. 5 a.
- the retainer 84 is locked to the arms 46 d by the circlip 85 .
- the circlip 85 is fitted into a groove 46 e provided in each arm 46 d on the inner periphery of the housing body 46 c (see FIG. 4 ).
- the retainer 84 is locked to the arms 46 d and supports an outer side end 83 a of the disc spring 83 .
- the roller retainer 78 supports an inner side end 83 b of the disc spring 83 as shown in FIG. 8 .
- the retainer 84 experiences a reaction force to the biasing force of the disc spring 83 against each roller weight 41 , with the force being applied from left to right in FIG. 8 .
- the circlip 85 is fitted into the circlip groove 46 e so as to prevent detachment of the retainer 84 from the housing body 46 c by this reaction force. Further, by fitting the circlip 85 into the circlip groove 46 e, the circlip 85 restricts movement of at least the pressure plate 77 and the roller weight 41 (among constituent elements of the clutch 2 ) in the axial direction of the main shaft 33 (see FIG. 3 ). Due to this, it is possible to ensure that the pressure plate 77 receives the centrifugal force of each roller weight 41 generated by rotation of clutch housing 46 .
- the circlip 85 is suppressed from deforming radially inward by the stopper 84 c provided on the retainer 84 .
- the height of the stopper 84 c (when viewed in the crosswise direction in FIG. 6 b ) is not limited to a specific value and may be set to any height capable of suppressing the radial inward deformation of the circlip 85 during actuation of the power unit 3 so as to prevent detachment of the circlip 85 .
- the circlip 85 locks the retainer 84 and is fitted into the housing body 46 c in the following order.
- the arms 46 d of the clutch housing 46 are inserted into the mount holes 84 a of the retainer 84 .
- the slide shaft 201 is rotated in a predetermined direction by a tool such as a driver to allow the pressure plate 77 to press-contact the plate group 66 .
- the outer diameter of the circlip 85 is reduced to be smaller than the inner diameter of the circlip groove 46 e.
- the outer diameter of the circlip 85 is reduced by compressing the circlip 85 until contact occurs between left and right terminal ends of the circlip 85 which are normally separated from each other by the slit or notched portion 85 b, as shown in FIG. 5 .
- the reduced circlip 85 is fitted into the circlip groove 46 e.
- the outer circumference side of the circlip 85 is fitted into the circlip groove 46 e. Further, even if the diameter of the circlip 85 is reduced during actuation of the power unit 3 , the inner arcuate surface of the circlip 85 would be contacted by the stopper 84 c. Due to this, reduction of the inner diameter of the circlip 85 is restricted. In other words, the inner diameter of the circlip 85 is hardly reduced during actuation of the power unit 3 . It is, therefore, possible to prevent detachment of the circlip 85 from the arms 46 d by providing the stopper 84 c on the retainer 84 .
- Circlip 85 of FIG. 5( a ) may also be utilized in a first modification of the above-described embodiment.
- pin stoppers 94 b are provided in a circular fashion on a retainer 94 according to the first modification.
- the pin stoppers 94 b are ribs formed on a front surface of the retainer 94 .
- the retainer 94 is locked to the arms 46 d by the circlip 85 .
- the circlip 85 is suppressed from deforming radially inward by the stoppers 94 b provided on the retainer 94 .
- the number of the stoppers 94 b and spacing intervals thereof are not limited specifically.
- each of the stoppers 94 b (when viewed in the crosswise direction in FIG. 9 b ) is not limited to a specific value and may be set to any height capable of suppressing the radial inward deformation of the circlip 85 so as to prevent detachment of the circlip 85 during actuation of a power unit 3 .
- the manner of forming the stoppers 84 b is not limited to forming of ribs on the surface of the retainer 84 .
- commonly used screws may be screwed into screw holes (not shown) provided in the retainer 84 with the heads of the screws which remain on the surface of the retainer 84 being used as the stoppers, respectively.
- Circlip 85 of FIG. 5( a ) may also be utilized in a second modification of the above-described first embodiment.
- the circlip 85 used in the second modification is similar to the circlip 85 used in the first modification.
- a stopper 104 d is provided in one portion of an annular retainer 104 .
- the stopper 104 d is a rib formed on a front surface of the retainer 104 .
- the retainer 104 is locked to arms 46 d by the circlip 85 .
- the circlip 85 is suppressed from deforming radially inward by the stopper 104 d (provided on the retainer 104 ) and housing body 46 c.
- the position of the stopper 104 d is not limited to a specific position on the annular portion of the front surface of the retainer 104 .
- the position of the stopper 104 d may be set to a position capable of suppressing the radial inward deformation of the circlip 85 so as to prevent the detachment of the circlip 85 during actuation of power unit 3 .
- the manner of forming the stopper 104 d is not limited to forming a rib on the front surface of the retainer 104 .
- a commonly used bolt may be screwed into a bolt hole (not shown) provided on the outer surface of the annular portion of the retainer 104 with the head of the bolt, which remains on the surface of the retainer 84 , being used as a stopper.
- the clutch 2 according to the first embodiment can suppress the radially inward deformation of the circlip 85 during driving of the engine 4 .
- the clutch 2 can suppress the radially inward deformation of the circlip 85 .
- the clutch 2 includes a stopper suppressing the radially inward deformation of the circlip 85 .
- the stopper suppressing the radially inward deformation of the circlip 85 is the stopper 84 c, stoppers 94 b or the stopper 104 d provided on the surface of the retainer 84 , the retainer 94 and the retainer 104 , respectively.
- the circlip 85 is suppressed from deforming radially inward by the stopper during driving of the engine 4 . It is, therefore, possible to prevent detachment of the circlip 85 from the clutch housing 46 .
- the position of the circlip 85 in the housing body 46 c can be held and the circlip 85 can be prevented from detaching from the arms 46 d without increasing the number of components related to the clutch 2 .
- the clutch 2 is a centrifugal friction clutch.
- the clutch 2 includes the centrifugal weights 41 and the roller retainer 78 .
- Each of the centrifugal weights 41 receives a centrifugal force by rotation of the clutch housing 46 and moves radially outward from the axis of the main shaft 33 .
- Each of the cam surfaces 81 which are provided on the pressure plate 77 , restricts movement of one of the centrifugal weights 41 in the centrifugal direction and converts the centrifugal force into a force in the axial direction of the main shaft 33 .
- the roller retainer 78 stops movement of the centrifugal weight 41 in the axial direction and supports the inner side end 83 b of the disc spring 83 .
- the retainer 84 supports the outer side end 83 a of the disc spring 83 .
- the retainer 84 receives the biasing force of the disc spring 83 . Due to this, in the centrifugal friction clutch 2 according to the present embodiment, the biasing force of the disc spring 83 loaded onto the retainer 84 is greater than when compared with a non-centrifugal friction clutch.
- the circlip 85 locks the retainer 84 , 94 or 104 , respectively, by being fitted into the housing body 46 c. Therefore, the clutch 2 according to the first embodiment exhibits a greater advantage of preventing the detachment of the circlip 85 than that of the non-centrifugal friction clutch.
- the clutch 2 is a multiple-disc friction clutch.
- the clutch 2 includes a plurality of friction plates 64 supported on the clutch housing 46 and a plurality of clutch plates 65 supported on the clutch boss 48 .
- the plurality of friction plates 64 and the plurality of clutch plates 65 are alternately arranged in a predetermined direction. Further, the pressure plate 77 forces the friction plates 64 to make contact with the clutch plates 65 by moving in the predetermined direction.
- the disc spring 83 applies a (biasing) force assisting in making the contact between the friction plates 64 and the clutch plates 65 .
- the retainer 84 receives the biasing force of the disc spring 83 by supporting the outer side end 83 a of the disc spring 83 .
- the disc spring 83 needs a greater biasing force than that in a friction clutch that is not of the multiple-disc type having a plurality of pairs of friction plates 64 and clutch plates 65 . Due to this, in the multiple-disc friction clutch according to the present embodiment, the biasing force of the disc spring 83 loaded onto the retainer 84 is greater than that in the friction clutch that is not of the multiple-disc type. Further, the circlip 85 locks the retainer 84 by being fitted into the housing body 46 c. Therefore, the clutch 2 according to the present embodiment exhibits a greater advantage of preventing detachment of the circlip 85 than that of the friction clutch that is not of the multiple-disc type.
- the clutch 2 includes the power-assist mechanism 200 .
- the power-assist mechanism 200 By including the power-assist mechanism 200 in a large-capacity clutch such as the clutch 2 , it is possible to facilitate disengaging the clutch 2 by the clutch lever 24 ( FIG. 1 ). Namely, as compared with a clutch that does not include the power-assist mechanism 200 , the force required to disengage the clutch can be reduced. In other words, the power-assist mechanism 200 is provided in the clutch so as to reduce the force required to manipulate the large-capacity clutch.
- the diameter of each of the plates for example, the friction plates 64 and the clutch plates 65 , as related to disengagement of the clutch 2 is larger than that of each of plates in a small-capacity clutch. Accordingly, the diameter of the clutch housing 46 covering up the friction plates 64 and the clutch plates 65 is larger than that in the small-capacity clutch. Moreover, the disc spring 83 applies the force assisting in the contact between the friction plates 64 and the clutch plates 65 . Due to this, the disc spring 83 needs a greater biasing force than that in the small-capacity clutch.
- the retainer 84 receives the reaction force to the biasing force of the disc spring 83 by supporting the outer side end 83 a of the disc spring 83 .
- the circlip 85 locks the retainer 84 by being fitted into the arms 46 d of the housing body 46 c.
- the inner diameter of the circlip 85 is large compared with the small-diameter clutch. Due to this, during actuation of the power unit 3 , a greater centrifugal force is generated on the entire circlip 85 than in the small-capacity clutch.
- the clutch 2 exhibits the advantage of being more capable of preventing the detachment of the circlip 85 than that of the small-capacity clutch.
- the clutch 2 according to the embodiment can be used in a vehicle.
- the vehicle including the clutch 2 can run stably in various running conditions because the detachment of the circlip 85 is prevented.
- the clutch 2 according to the present embodiment can be used in a motorcycle.
- the motorcycle often requires complicated throttle operation as compared with other types of vehicles.
- the engine 4 is driven at higher engine speed than that of the engine of the other types of vehicles. Due to this, the main shaft 33 of the clutch 2 is driven at a higher rotational speed.
- a greater centrifugal force is generated on the circlip 85 fitted into the clutch housing 46 by driving at the higher engine speed. If a relatively great centrifugal force is generated on the entire circlip 85 , a greater frictional force is generated between the outer circumferential side of the circlip 85 and the inner hull of the housing body 46 c.
- the clutch 2 exhibits the greater advantage of preventing the detachment of the circlip 85 by being included in the motorcycle 1 .
- At least one stopper is provided on the retainer as means for suppressing the radially inward deformation of the circlip 85 .
- the means for suppressing the radially inward deformation of the circlip 85 is not necessarily limited to a structure provided on the retainer 84 .
- the circlip 85 may also be structured to suppress the radially inward deformation of the circlip 85 .
- a circlip 95 is substantially ring-shaped so as to lock a retainer 304 ( FIGS. 15 a and 15 b ) to housing body 46 c.
- Circlip 95 is provided with a slit or notched portion 95 a as depicted in FIG. 16 a.
- the shape and angular inclination of the slit 95 a are not limited specifically as long as the annular portion of the circlip 95 is broken in one portion.
- the slit 95 a bisects the annular portion of circlip 95 at a right angle to the outer circumference of the circlip 95 .
- a width W of the slit 95 a as shown in FIG.
- the width W satisfies the relationship T ⁇ (D 1 ⁇ D 2 )/2, wherein the outer diameter of the circlip 95 is designated D 1 , the inner diameter thereof is designated D 2 , and T stands for the width W of the slit 95 a.
- the retainer 304 has such a shape as to be fitted into an outer hull of the housing body 46 c.
- a clutch housing 46 has a cylindrical shape. Due to this, the retainer 304 has an annular shape.
- Mount holes 304 a are formed in the retainer 304 and arms 46 d (see FIGS. 3 and 4 ) of the housing body 46 c are fitted into the mount holes 304 a.
- the retainer 304 is locked to the arm 46 d by the circlip 95 .
- a circlip groove 46 e into which the outer circumferential side of the circlip 95 is fitted, is provided in each of the arms 46 d on an inner periphery of the housing body 46 c (see FIG. 4 ).
- the retainer 304 is locked to the arms 46 d and supports the outer side end 83 a of disc spring 83 .
- Roller retainer 78 supports the inner side end 83 b of the disc spring 83 , as stated above.
- the retainer 304 experiences a reaction force to the biasing force of the disc spring 83 against each roller weight 41 , with the force being applied from left to right in FIG. 18 .
- the circlip 95 is fitted into the circlip groove 46 e so as to prevent detachment of the retainer 304 from the housing body 46 c by this reaction force. Further, by fitting the circlip 95 into the circlip groove 46 e, the circlip 95 restricts movement of at least the pressure plate 77 and the roller weight 41 (among constituent elements of the clutch 2 ) in the axial direction of the main shaft 33 (see FIG. 3 ). Due to this, it is possible to ensure that the pressure plate 77 receives the centrifugal force of each roller weight 41 generated by rotation of clutch housing 46 .
- the circlip 95 locks the retainer 304 and is fitted into the housing body 46 c in the following order.
- the arms 46 d of the clutch housing 46 are inserted into the mount holes 304 a of the retainer 304 .
- the slide shaft 201 is rotated in a predetermined direction by a tool such as a driver to allow the pressure plate 77 to press-contact the plate group 66 .
- the outer diameter of the circlip 95 is reduced to be smaller than the inner diameter of the circlip groove 46 e.
- the outer diameter of the circlip 95 is reduced by compressing the circlip 95 to cross the left and right terminal ends, which are normally separated by slit 95 a as shown in FIG. 16 a, with each other.
- the reduced circlip 95 is fitted into the circlip groove 46 e.
- the crossing portions overlap each other on front and rear surfaces of the sheet of FIG. 16 (i.e., crosswise in FIGS. 3 and 4 ).
- a portion in which the left and right terminal ends of the circlip 95 overlap each other has a thickness that is twice or more as large as that of other portions of the circlip 95 . Due to this, one of the circlip grooves 46 e has a width twice or more as large as that of the other circlip grooves 46 e in one of the portions and regions of the plurality of arms 46 d so that the portion in which the left and right terminal ends of the circlip 95 overlap each other can be fitted into the housing body 46 c.
- the portion and region in which the twice or more width is set are not limited to a specific one of the arms 46 d as long as the circlip 95 does not detach during actuation of power unit 3 .
- the left and right terminal ends of the circlip 95 can contact each other in the area defined by the slit 95 a. Namely, even if the inner diameter of the circlip 95 is to be reduced, the inner diameter is hardly reduced during actuation of the power unit 3 since both terminal ends of the circlip 95 across the slit 95 a abut on each other. Therefore, it is possible to prevent detachment of the circlip 95 from the arms 46 d by providing the slit 95 a in the circlip 95 .
- the clutch 2 according to the second embodiment is configured to suppress the radially inward deformation of the circlip 95 .
- Examples of a configuration for suppressing the radially inward deformation of the circlip 95 include the slit 95 a formed by bisecting the annular circlip 95 .
- the left and right terminal ends of the circlip 95 can contact each other in the area defined by the slit or notched portion 95 a even if the inner diameter of the circlip 95 is to be reduced while engine 4 is being driven. Namely, even if the inner diameter of the circlip 95 is to be reduced, both terminal ends of the circlip 95 abut on each other in the slit or notched portion 95 a. Due to this, the inner diameter of the circlip 95 is hardly reduced during actuation of the power unit 3 . It is, therefore, possible to prevent detachment of the circlip 95 from the clutch housing 46 .
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mechanical Operated Clutches (AREA)
- One-Way And Automatic Clutches, And Combinations Of Different Clutches (AREA)
Abstract
A friction clutch has a clutch housing including a friction plate, a clutch boss including a clutch plate, and a pressure plate causing the friction plate and the clutch plate to contact each other by moving in a predetermined direction. A clutch spring applies a biasing force in a direction of causing the pressure plate to press the friction and clutch plates into contact with each other. An annular retainer receives a reaction force to the biasing force of the clutch spring by supporting one end of the clutch spring opposite to the pressure plate. A circlip of a notched ring shape is fitted into an inner peripheral side of the clutch housing. The circlip locks the retainer to the clutch housing by abutting on an opposite side of the retainer. The retainer is configured to suppress radially inward deformation of the circlip when a vehicle engine is driven.
Description
- This patent application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2008-043510, filed on Feb. 25, 2008, the entire contents of which is hereby expressly incorporated by reference.
- The present invention relates to a friction clutch.
- There is conventionally known a friction clutch configured to restrict positions of constituent elements of the friction clutch such as clutch plates and a clutch spring related to rotation of a clutch shaft in an axial direction of the clutch shaft. The friction clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177, for example, has such a structure.
- The friction clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177 is a multiple-disc automatic centrifugal friction clutch used in a motorcycle. The multiple-disc automatic centrifugal friction clutch includes a clutch shaft (=main shaft), a drive plate (=friction plate), and a driven plate (=clutch plate). Furthermore, the multiple-disc automatic centrifugal friction clutch includes a weight roller (=centrifugal weight) and a pressure plate. The pressure plate and the drive plate can slidably move in an axial direction (=thrust direction) of the clutch shaft. By movement of the pressure plate in the thrust direction, the drive plate and the driven plate are pressed. The weight roller receives a centrifugal force by rotation of the clutch shaft and moves radially outward of the clutch shaft. The centrifugal force of the weight roller is converted into a pressing force in the thrust direction of the pressure plate due to the internal structure of the clutch. The drive plate and the driven plate are pressed by the pressing force of the pressure plate. The drive plate and the driven plate which are pressed transmit a drive force of an engine of the motorcycle to a rear wheel.
- Moreover, the multiple-disc automatic centrifugal friction clutch includes a clutch plate spring (=clutch spring) generating the pressing force of the pressure plate. Namely, the clutch plate spring presses the drive plate and the driven plate. Further, the pressurization on the drive plate and the driven plate holds the drive plate and the driven plate at predetermined positions at predetermined intervals. Due to this, the multiple-disc automatic centrifugal friction clutch includes a circlip (retaining ring) for restricting positions of constituent elements of a clutch housing such as the pressure plate, the drive plate, the driven plate, the centrifugal weight, and the clutch plate spring in the axial direction of the clutch shaft. This circlip is fitted into the clutch housing covering up the drive plate and the driven plate included in the clutch. A position at which the circlip is fitted into the clutch housing is one end side of the clutch housing in the axial direction of the clutch shaft. The circlip restricts positions of the constituent elements of the clutch housing such as the plate, the centrifugal weight, and the clutch plate spring related to rotation of the clutch shaft in the axial direction of the clutch shaft by being fitted into the clutch housing. Further, the circlip receives a reaction force to the biasing force of the clutch plate spring and prevents detachment of such plates as the drive plate and the driven plate from the clutch housing by being fitted into the clutch housing.
- However, if engine power is to be improved in a motorcycle or the like, it is necessary to ensure transmitting the drive force of the high-power engine. Due to this, the clutch serving as a transmission mechanism transmitting the drive force of the engine is configured, for example, so that the diameters of the plates including the friction plate and the clutch plate are increased so as to correspond to the configuration of the high-power engine. In the clutch having such larger-diameter plates, the diameter of the circlip preventing detachment of such plates as the friction plate and the clutch plate is also made larger.
- Nevertheless, the inventor of the present application has discovered from various experiments that the circlip often detaches from the clutch housing in friction clutches including a larger diameter circlip.
- The present invention has been devised in view of the foregoing problems, and it is an object of the present invention to prevent a retaining ring (such as a circlip) from detaching from a clutch housing.
- The inventor of the present application has exerted utmost efforts as well as conducted studies to attain the foregoing object and has discovered that a main cause for detachment of the circlip is a radially inward deformation of the circlip. Specifically, the inventor has discovered that the shape of the circlip and the load imposed on the circlip play a role in the detachment of the circlip. The circlip typically has a substantially annular shape in which an outer circumferential side of the circlip is fitted into the clutch housing. Consequently, deformation of the circlip tends to occur on the inner circumferential side rather than on the outer circumferential side. This deformation is considered to result from the fact that the circlip has the substantially annular shape and, more particularly, has a so-called C shape with a slit formed in a portion of the circlip.
- A C-
shaped circlip 85 is shown, for example, inFIGS. 5 a and 5 b. Circlip 85 has a slit or notchedportion 85 b. Whencirclip 85 is fitted into a clutch housing, the diameter of the outer circumference of the circlip is temporarily reduced so as to be smaller than an inner hull of the clutch housing. The diameter of the circlip is reduced, for example, by applying an external compressing force to the circlip so that the terminal ends ofcirclip 85 come into contact with each other. The circlip fitted into the clutch housing generates an expanding force extending along the circlip diameter (hereinafter, referred to as “extension force”). This extension force enables the inner hull of the clutch housing and the outer circumference of this circlip to contact each other. - Furthermore, similarly to the clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177, the clutch employing the circlip shown in
FIGS. 5 a and 5 b often includes a clutch spring (clutch plate spring). In this case, similarly to the circlip described in Japanese Laid-Open Patent Application Publication No. 2003-322177,circlip 85 is fitted into the clutch housing, thereby receiving a reaction force to the biasing force of the clutch spring. The reaction force to the biasing force of the clutch spring causes the front and rear terminal end surfaces (FIG. 5 a) of the circlip to make contact with the clutch housing. The contact of thecirclip 85 with the clutch housing allows thecirclip 85 and the clutch housing to generate a frictional force in a portion in which thecirclip 85 and the clutch housing contact each other. - Moreover, if the clutch including the
circlip 85 is a centrifugal clutch similar to the clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177, the magnitude of the reaction force to the biasing force of the clutch spring varies according to the change in rotational speed of the clutch shaft. Namely, in the case of the clutch described in Japanese Laid-Open Patent Application Publication No. 2003-322177, for example, the weight roller receives the centrifugal force and moves radially outward relative to the clutch shaft by rotation of the clutch shaft. The centrifugal force of the weight roller is converted into a pressing force in the thrust direction of the pressure plate by the internal structure of the clutch. The drive plate and the driven plate are pressed by the pressing force of the pressure plate. During pressing, the drive plate and the driven plate are forced to separate from each other by mutual resistance forces or the like. Due to this, the clutch includes the clutch plate spring as means for generating the pressing force. If the rotational speed of the clutch shaft is higher, the clutch plate spring needs a greater biasing force for pressing the drive plate and the driven plate. In this way, if the biasing force of the clutch disc spring is of relatively high magnitude, the circlip receives a greater reaction force to the biasing force of the clutch plate spring. If the reaction force to the biasing force of the clutch plate spring is greater, a greater frictional force is generated in the portion of the circlip that contacts the clutch housing. - Further, as the clutch shaft rotates, a centrifugal force is generated at mass points on a circular portion of the circlip. This centrifugal force is greater if the rotational speed of the clutch shaft is higher. This centrifugal force and the extension force of the circlip described previously enable the circlip to make contact with the inner hull of the clutch housing on the outer circumferential side of the circlip.
- As stated above, the outer circumferential side of the circlip contacts the inner hull of clutch housing by the extension force which is directed radially outward of the circlip. Further, the circlip receives the reaction force to the biasing force of the clutch spring. The front and rear surfaces (front and rear surfaces in
FIG. 5 a) of the circlip make contact with the clutch housing due to the reaction force of the clutch housing to the biasing force. Due to this, a frictional force is generated in the portion of the circlip that contacts the clutch housing. However, the frictional force applied to the portion of the circlip that contacts the clutch housing is not uniform on the entire circlip. Namely, the force due to friction with the clutch housing differs in magnitude or the like among the mass points on the circlip. This results from the fact that the shape of the outer circumferential side of the circlip does not completely conform to the shape of the inner hull of the clutch housing. Furthermore, surfaces of the circlip and the clutch housing are not completely flat physically, so that portions in which the clutch housing contacts the circlip may include small spaces therebetween. Besides, during driving of the engine related to actuation of the clutch, the frictional force is considered to change at the respective mass points on the circlip. - If the frictional force changes at the respective mass points on the circlip, the circlip is considered to undergo deformation. However, the outer circumferential side of the circlip can make contact with the inner hull of the clutch housing. Due to this, it is considered that the inner circumferential side of the circlip deforms more easily than the outer circumferential side thereof.
- The inventor of the present patent document has conducted studies concerning the radially inward deformation of the circlip, and, as a result attained the inventions described herein. In one aspect, the invention is directed to a friction clutch. In one embodiment, the friction clutch includes a main shaft driven to rotate by the engine, a clutch housing including a first plate, and rotating along the main shaft, a clutch boss including a second plate opposed to the first plate in a predetermined direction, a pressure plate causing the first plate and the second plate to contact each other by moving in the predetermined direction, a clutch spring arranged on the opposite side of the pressure plate relative to the first and second plates in the predetermined direction, the clutch spring having a biasing force in a direction of causing the first plate and the second plate to contact each other to the pressure plate, a retainer formed into a substantially circular shape and receiving a reaction force to the biasing force of the clutch spring by supporting one end of the clutch spring opposite to the pressure plate, and a retaining ring having a substantially circular shape, the retaining ring having a slit which extends in a radial direction and is formed in a circumferential part of the retaining ring, the retaining ring being fitted into an inner peripheral side of the clutch housing, the fitted retaining ring locking the retainer to the clutch housing by abutting on an opposite side of the retainer relative to the clutch spring, the friction clutch being configured to suppress the circlip from deforming radially inward.
- With the foregoing arrangement, it is possible to prevent detachment of the retaining ring (circlip or the like) from the clutch housing.
- In another aspect, the invention is directed at a vehicle, such as a motorcycle, including a frictional clutch as described herein.
-
FIG. 1 is a side view of a motorcycle. -
FIG. 2 is a schematic diagram illustrating the main components of a power unit of the motorcycle ofFIG. 1 . -
FIG. 3 is a cross-sectional view of a clutch of the motorcycle ofFIG. 1 . -
FIG. 4 is a partial perspective view of a clutch housing viewed obliquely from the top. -
FIG. 5 a is a front view of a circlip according to a first embodiment. -
FIG. 5 b is a cross-sectional view of the circlip ofFIG. 5 a. -
FIG. 6 a is a front view of a retainer according to the first embodiment. -
FIG. 6 b is a cross-sectional view of the retainer ofFIG. 6 a. -
FIG. 7 is a front view showing a state in which the retainer and circlip are attached to a clutch housing according to the first embodiment. -
FIG. 8 is an enlarged partial cross-sectional view of a clutch utilizing the retainer and circlip ofFIG. 7 according to the first embodiment. -
FIG. 9 a is a front view of a retainer according to a first modification of the first embodiment. -
FIG. 9 b is a cross-sectional view of the retainer ofFIG. 9 a. -
FIG. 10 is a front view showing a state in which the retainer ofFIG. 9 a and a circlip are attached to a clutch housing according to the first modification. -
FIG. 11 is an enlarged partial cross-sectional view of a clutch according to the first modification. -
FIG. 12 a is a front view of a retainer according to a second modification of the first embodiment. -
FIG. 12 b is a cross-sectional view of the retainer ofFIG. 12 a. -
FIG. 13 is a front view showing a state in which the retainer ofFIG. 12 a and a circlip are attached to a clutch housing according to the second modification. -
FIG. 14 is an enlarged partial cross-sectional view of a clutch utilizing the retainer ofFIG. 12 . -
FIG. 15 a is front view of a retainer according to a second embodiment. -
FIG. 15 b is a cross-sectional view of the retainer ofFIG. 15 a. -
FIG. 16 a is front view of a circlip according to the second embodiment. -
FIG. 16 b is a cross-sectional view of the circlip ofFIG. 16 a. -
FIG. 17 is a front view showing a state in which the retainer and circlip ofFIGS. 15 a and 16 b, respectively, are attached to a clutch housing. -
FIG. 18 is an enlarged partial cross-sectional view of a clutch utilizing the retainer and circlip ofFIG. 17 . - Prior to describing the embodiments of the present invention, the background of the present invention will be described first.
- As already stated, in the clutch having larger-diameter plates such as the friction plate and the clutch plate, the diameter of the circlip preventing detachment of such plates as the friction plate and the clutch plate is also made larger. Furthermore, since it is necessary to increase the pressing force of the pressure plate (which presses the friction plate and the clutch plate), the biasing force of the clutch spring urging this pressing force is also increased. If the biasing force of the clutch spring is greater, the load imposed on the circlip receiving the reaction force to the biasing force of the clutch spring becomes heavier.
- The centrifugal force is generated at respective mass points on the circlip when the clutch shaft rotates during driving of the engine. In a high-power engine, a greater centrifugal force according to the mass of the circlip is generated in a larger-diameter circlip than in a smaller-diameter circlip. Moreover, if the clutch shaft rotates at high speed by being driven by the engine at high engine speed, a greater centrifugal force is generated than that generated when the clutch shaft rotates at low rotational speed.
- Furthermore, the length of a circular arc on the outer circumferential side of the circlip which is in contact with the inner hull of the clutch housing would be a function of the diameter of the circlip. Due to this, if the circlip has a larger diameter, the contact area between the inner hull of the clutch housing and the outer circumferential side of the circlip is also larger. Therefore, the frictional force generated between the outer circumferential side of the larger-diameter circlip and the inner hull of the clutch housing varies in accordance with the size of the contact area.
- The detachment of the circlip is conspicuously recognized when the drive force is instantaneously recovered from driving of the engine at high engine speed. Namely, the detachment of the circlip is a phenomenon that occurs when a throttle valve used to drive the engine is closed to a minimum opening position instantaneously from a maximum opening position. Due to this, the inventor of the present application has considered, as a cause for the detachment of the circlip, a sudden drop in the rotational speed of the clutch shaft and a sudden drop in the centrifugal force on the entire circlip, accordingly. Further, when the centrifugal force of the entire circlip suddenly drops, it is considered that the frictional force between the circlip and the clutch housing also suddenly falls. The circlip for which the frictional force between the circlip and the clutch housing falls is considered to rotate relative to the clutch housing. The rotation of the circlip relative to the clutch housing is considered to result from sliding of the circlip having an inertial force generated by the rotation of the clutch shaft on the clutch housing having the reduced frictional force.
- As already stated, the frictional force differs among the mass points on the circlip in magnitude or the like. Due to this, during the relative rotation of the circlip to the clutch housing, it is considered that the inertial force is greater than the frictional force at some mass points and that the frictional force is greater than the inertial force at other mass points. Therefore, the inventor of the present application has estimated that the circlip deforms according to changes in the magnitude or the like of the frictional force at respective mass points on the circular portion of the circlip.
- In Japanese Laid-Open Patent Application Publication No. 2003-322177, the shape of the circlip is not limited to a specific shape. However, the circular C shape (see
FIG. 5 ) is popular and normally adopted as the shape of the circlip. Due to this, the inventor of the present application has used a C-shaped circlip in a clutch without exception. As shown inFIG. 5 a, thecirclip 85 includes slit or notchedportion 85 b. Since the outer circumferential side of thecirclip 85 is fitted into the clutch housing, the deformation of the outer circumferential side of thecirclip 85 is less likely to occur. However, the inner circumferential side of thecirclip 85 is considered to deform more easily than the outer circumferential side thereof. - If the inner circumferential side of the
circlip 85 deforms radially inward, thecirclip 85 often temporarily detaches from the portion (clutch housing) held in the clutch instantaneously. Even if a detached portion is only a part of thecirclip 85, thecirclip 85 instantaneously detaches from the clutch housing due to the significant biasing force of the clutch spring. - Therefore, an interior of the clutch is configured to suppress the radially inward deformation of the circlip so as to be able to prevent the detachment of the circlip from the clutch housing.
- A vehicle including a centrifugal clutch according to embodiments of the present invention will be described hereinafter in detail with reference to the drawings. It is to be noted, however, that the vehicle described below is only an example of a preferred mode for carrying out the present invention. The vehicle according to the present invention is not limited to a motorcycle 1 described below. In the present specification, the term “motorcycle” refers to a vehicle of the type whose vehicle body is designed to be leaned when making a turn. Accordingly, the term “motorcycle” as used herein is not limited to a vehicle including two wheels but may also include vehicles including three or more wheels.
-
FIG. 1 is a left side view of a motorcycle 1 according to an embodiment. In the following description, it is assumed that longitudinal and crosswise directions are directions viewed from a passenger seated on aseat 16 to be described later. - As shown in
FIG. 1 , motorcycle 1 includes a vehicle body 7, afront wheel 14 provided at a front section of the vehicle body 7, and arear wheel 19 provided at a rear section of the vehicle body 7. - The vehicle body 7 includes a
vehicle body frame 10. Thevehicle body frame 10 includes ahead pipe 11. Ahandlebar 12 is provided to an upper end portion of thehead pipe 11. In addition, thefront wheel 14 is rotatably mounted to a lower end of thehead pipe 11 via afront fork 13. - A
power unit 3 is suspended from thevehicle body frame 10. Avehicle body cover 15 is attached to thevehicle body frame 10. Aseat 16 is disposed so as to extend rearward from a substantially central position of the vehicle body 7 to the rear side thereof in the front-rear direction. A fuel tank 17 is disposed in front of theseat 16. - A
rear arm 18 is pivotally supported on thevehicle body frame 10. Therear wheel 19, which serves as a drive wheel, is rotatably attached to a rear end of therear arm 18. Therear wheel 19 is connected to an engine 4 (seeFIG. 2 ) through a power transmission mechanism (not shown). The drive force of theengine 4 is thereby transmitted to therear wheel 19 so that therear wheel 19 rotates. - An accelerator grip (not shown) is provided on the right side of the
handlebar 12. Aleft grip 29 is provided on the left side of thehandlebar 12. Aclutch lever 24 that is operated to engage/disengage friction clutch 2 (seeFIG. 2 ), which is described later, is provided in front of theleft grip 29 of thehandlebar 12. -
Footrests 20L are provided on each side of the vehicle body 7 at a central portion thereof in the front-rear direction. Ashift pedal 27 is operated to change the transmission gear ratio of a transmission 5 (seeFIG. 2 ), which will be described later, is provided on the left side of the vehicle body 7 at a position slightly in front of theleft footrest 20L. A side stand 28 is provided on the left side of the vehicle body 7 at a position below theshift pedal 27 and thefootrest 20L. - The configurations of the main components of the
power unit 3 of motorcycle 1 will now be described with reference toFIG. 2 . As shown inFIG. 2 , thepower unit 3 includes theengine 4, thetransmission 5, and theclutch 2. In the present embodiment, while the type of theengine 4 is not limited to a particular type of engine, a water-cooled, four-cycle, parallel four-cylinder engine is used as theengine 4. - Although not shown, the
engine 4 includes four cylinders, a piston reciprocating in each of the respective cylinders, and acrankshaft 32 connected to each of the pistons via a connecting rod. Thecrankshaft 32 extends in a vehicle width direction.Reference numeral 31 denotes a crankcase. - As shown in
FIG. 2 , thecrankshaft 32 is connected to thetransmission 5 via theclutch 2. Thetransmission 5 includes amain shaft 33, adrive shaft 23, and agear selection mechanism 36. Themain shaft 33 is connected to thecrankshaft 32 via theclutch 2. Themain shaft 33 and thedrive shaft 23 are disposed parallel to thecrankshaft 32, respectively. - A plurality of multi-stage transmission gears 34 are mounted on the
main shaft 33. A plurality of transmission gears 35 corresponding to the multi-stage transmission gears 34 are mounted on thedrive shaft 23. The multi-stage transmission gears 34 and the plurality of transmission gears 35 are disposed so that only one pair of selected gears is engaged with each other. Either the transmission gears 34 excluding the selectedtransmission gear 34 or the transmission gears 35 excluding the selected transmission gear 35 are rotatable with respect to themain shaft 33 or thedrive shaft 23 or both. That is, at least one of the non-selected transmission gears 34 or the non-selected transmission gears 35 run idle with respect to themain shaft 33 or thedrive shaft 23. In other words, rotation is transmitted between themain shaft 33 and thedrive shaft 23 only via the selectedtransmission gear 34 and the selected transmission gear 35 which are engaged with each other. - The transmission gears 34 and 35 are selected by the
gear selection mechanism 36. Specifically, the transmission gears 34 and 35 are selected by ashift cam 37 of thegear selection mechanism 36. A plurality ofcam grooves 37 a are formed on an outer circumferential surface of theshift cam 37. Ashift fork 38 is engaged with each cam groove 37 a. Eachshift fork 38 is engaged with predetermined transmission gears 34 and 35 of themain shaft 33 and thedrive shaft 23, respectively. As theshift cam 37 rotates, a plurality ofshift forks 38 are guided in theirrespective cam grooves 37 a to move in a direction of themain shaft 33, so that gears to be engaged with each other are selected from among the transmission gears 34 and 35. Specifically, among the multi-stage transmission gears 34 and the plurality of transmission gears 35, only one pair of gears disposed at positions corresponding to a rotational angle of theshift cam 37 are fixed with respect to themain shaft 38 and thedrive shaft 23 by a spline. As a result, the transmission gear position is determined, and rotation between themain shaft 33 and thedrive shaft 23 is transmitted at a predetermined transmission gear ratio through the transmission gears 34 and 35. Thegear selection mechanism 36 is operated by theshift pedal 27 shown inFIG. 1 . - With this configuration, after a pair of transmission gears 34 and 35 is fixed to the
main shaft 33 and thedrive shaft 23 and theclutch 2 is engaged, when theengine 4 is driven a drive force of theengine 4 is transmitted to themain shaft 33 through theclutch 2. Further, the rotation is transmitted at a predetermined transmission gear ratio between themain shaft 33 and thedrive shaft 23 via the predetermined pair of transmission gears 34 and 35, so that thedrive shaft 23 is driven to rotate. Whendrive shaft 23 is driven to rotate, drive force is transmitted by a transmission mechanism (not shown) such as a chain connecting thedrive shaft 23 and therear wheel 19, so that therear wheel 19 is rotated. In the present embodiment, a power transmission mechanism which connects theengine 4 and therear wheel 19 comprises the clutch 2, thetransmission 5 and a transmission mechanism (not shown) such as a chain. - In the present embodiment, the
clutch 2 is constituted by a multiple-disc friction clutch. Further, theclutch 2 is a centrifugal clutch that is automatically engaged or disengaged at the time of starting or stopping motorcycle 1 and which is optionally engaged or disengaged through the operation of theclutch lever 24 by a rider. A configuration of the clutch 2 will be described in detail. - As shown in
FIG. 3 , theclutch 2 includes aclutch housing 46. Themain shaft 33 extends through theclutch housing 46. Theclutch housing 46 includes ahousing body 46 c. Thehousing body 46 c is formed in a substantially cylindrical form that is closed at one end by a bottom 46 a. Themain shaft 33 also extends through the bottom 46 a of thehousing body 46 c. A plurality of pairs ofarms 46 d are provided on thehousing body 46 c. Eacharm 46 d extends outward from the bottom 46 a toward the outside in a vehicle width direction. Further, acirclip groove 46 e is provided in eacharm 46 d on the inner periphery of thearm 46 d as described later and as shown in reference toFIG. 4 . - As shown in
FIGS. 2 and 3 , the vehicle width direction may also be referred to as a left-right direction. In the present embodiment, theclutch 2 is disposed on the right side of themain shaft 33 such that the “outside” in the vehicle width direction corresponds to the right side, and “inside” in the vehicle width direction corresponds to the left side. Therefore, the “outside” and the “inside” in the vehicle width direction will be referred to simply as the “right side” and the “left side,” respectively. - A
scissor gear 45 is attached to theclutch housing 46. Thescissor gear 45 includes twogears plates gear 45 a and thegear 45 b are located between the twoplates plates main shaft 33. Therefore, the twogears main shaft 33. Meanwhile, thegears - The
gears gears gears gears engine 4 can be absorbed. - The
gear 45 a of thescissor gear 45 is engaged with agear 32 a (FIG. 2 ) of thecrankshaft 32. Thegear 45 a (of the scissor gear 45) is fixed to the bottom 46 a of theclutch housing 46 so as to be unrotatable relative thereto. With such a configuration, thegear 45 a of thescissor gear 45 and theclutch housing 46 integrally rotate following the rotation of thecrankshaft 32. - A
needle bearing 53 and aspacer 54, which is nonrotatably fixed to themain shaft 33, are disposed between thescissor gear 45 and themain shaft 33. Theneedle bearing 53 enables thescissor gear 45 to be rotatable with respect tomain shaft 33. In other words, rotation of thescissor gear 45 is not transmitted directly to themain shaft 33. - A
clutch boss 48 is nonrotatably fixed to themain shaft 33 by anut 67. That is, theclutch boss 48 rotates together with themain shaft 33. A thrust bearing 63 is disposed between theclutch boss 48 and thescissor gear 45. Thus, thescissor gear 45, theneedle bearing 53, and thespacer 54 are regulated so that they do not come closer than a predetermined distance to theclutch boss 48. In other words, movement of thescissor gear 45, theneedle bearing 53, and thespacer 54 toward theclutch boss 48 in the axial direction of themain shaft 33. - A plurality of
friction plates 64 are arranged inside theclutch housing 46. Eachfriction plate 64 is fixed to theclutch housing 46 with respect to the rotational direction of themain shaft 33. Thus, the plurality offriction plates 64 rotate together with theclutch housing 46. Eachfriction plate 64 is displaceable in the axial direction of themain shaft 33. Thus, the distance between twoadjacent friction plates 64 is variable. - The plurality of
friction plates 64 are arranged in the axial direction of themain shaft 33. Aclutch plate 65 is disposed betweenadjacent friction plates 64. Theclutch plate 65 is opposed to theadjacent friction plates 64. Eachclutch plate 65 is fixed to theclutch boss 48 with respect to the rotational direction of themain shaft 33. Thus, the plurality ofclutch plates 65 rotates together with theclutch boss 48. Further, eachclutch plate 65 is displaceable with respect to the axial direction of themain shaft 33. Thus, the distance between mutually adjacentclutch plates 65 is variable. - In the present embodiment, a
plate group 66 comprises the plurality offriction plates 64 and the plurality ofclutch plates 65, as shown inFIG. 3 . - A
pressure plate 77 is arranged on the right side of themain shaft 33, as depicted in reference toFIG. 3 . Thepressure plate 77 is formed into a substantially disc shape. Asub clutch 100, to be described later, is provided at a central portion of thepressure plate 77. A radially outward end of thepressure plate 77 is engaged witharms 46 d. Therefore, thepressure plate 77 is not rotatable with respect to theclutch housing 46 but it rotates together with theclutch housing 46. - A
pressing portion 77 b that projects toward theplate group 66 is formed on thepressure plate 77 at an outer section thereof, as illustrated inFIG. 3 . Thepressing portion 77 b faces therightmost friction plate 64 in theplate group 66. When thepressure plate 77 moves leftward, thepressing portion 77 b pushes theplate group 66 leftward. As a result, thefriction plates 64 and theclutch plates 65 in theplate group 66 are press-contacted into frictional contact with each other. - A plurality of cam surfaces 81, each of which supports a
roller weight 41, are formed on a surface opposite to theplate group 66 in the radially outward portion of thepressure plate 77. The plurality of cam surfaces 81 and the plurality ofroller weights 41 are provided along the circumferential direction. The plurality of cam surfaces 81 are arranged radially about the longitudinal axis of themain shaft 33. Eachcam surface 81 is inclined rightward as it moves outward in the radial direction. - A
roller retainer 78 is disposed on the right side of thepressure plate 77. Theroller retainer 78 is formed into a ring band shape when viewed from the axial direction of themain shaft 33. Theroller retainer 78 is opposed to thecam surface 81 of thepressure plate 77. Therefore, aspace 82 that becomes narrower in the radial direction of themain shaft 33 is formed by each cam surfaces 81 and theroller retainer 78. - Similar to the
pressure plate 77, a radially outward end of theroller retainer 78 is engaged with the plurality ofarms 46 d. Theroller retainer 78 is thereby nonrotatable about theclutch housing 46. In other words, theroller retainer 78 rotates together with theclutch housing 46. Meanwhile, theroller retainer 78 is displaceable with respect to theclutch housing 46 in the axial direction of themain shaft 33. - The
roller retainer 78 is urged leftward by adisc spring 83 which serves as a biasing member. In other words, theroller retainer 78 is urged toward theplate group 66 bydisc spring 83. Theroller retainer 78 and thedisc spring 83 constitute anabutment member 70 that presses theroller weights 41 toward the cam surfaces 81. - A
roller weight 41 is provided in each of a plurality ofspaces 82. Theroller weight 41 revolves following the rotation of theclutch housing 46 and moves on thecam surface 81 radially outward by means of a centrifugal force generated during the revolution. Theroller weight 41 receives a biasing force fromabutment member 70 and presses thepressure plate 77 toward the plate group (66) side. - When the rotational speed of the
crankshaft 32 is lower than a predetermined value, such as an idling state, the rotational speed of theclutch housing 46 also becomes lower. Therefore, centrifugal force applied to eachroller weight 41 is relatively small, and so theroller weight 41 is located relatively inward. Therefore, the force by which theroller weight 41 presses thepressure plate 77 leftward thereby weakens. As a result, the degree of pressure contact of theplate group 66 is reduced, and the torque transmittable from theclutch housing 46 to theclutch boss 48 thereby becomes relatively small. - On the other hand, when the rotational speed of the
crankshaft 32 becomes relatively high, the rotational speed of theclutch housing 46 also becomes relatively high. Hence, as the rotational speed of theclutch housing 46 increases, the centrifugal force exerted on theroller weights 41 also increases. If the centrifugal force exerted on theroller weights 41 is equal to or more than a predetermined value, theroller weights 41 move outward. Thepressure plate 77 is thereby pressed toward the left side by theroller weights 41 and moves toward theplate group 66. As a result, theplate group 66 is placed in a relatively strong pressed-contact state and the amount of torque that is transmittable from theclutch housing 46 to theclutch boss 48 is thereby relatively increased. - As shown in
FIG. 3 , the clutch 2 according to the present embodiment includes a sub-clutch 100. The sub-clutch 100 includes afriction plate 101, a firstpressing plate 102 that faces a left surface (hereinafter, “first friction surface”) 101 a of thefriction plate 101, and a secondpressing plate 103 that faces a right surface (hereinafter, “second friction surface”) 101 b of thefriction plate 101. - The clutch 2 according to the present embodiment includes a clutch release mechanism 86 (
FIG. 3 ). Theclutch release mechanism 86 forcibly releases a pressed-contact state of theplate group 66 in response to the operation of theclutch lever 24 by a rider. Theclutch release mechanism 86 enables the clutch 2 to be disengaged by the manual operation of a rider of the motorcycle 1. - As shown in
FIG. 3 , the clutch 2 according to the present embodiment includes a power-assist mechanism 200. The power-assist mechanism 200 converts part of the torque of thepressure plate 77 into a force for disengaging the clutch 2 so as to reduce the force required to disengage theclutch 2. The power-assist mechanism 200 according to the present embodiment comprises a so-called ball cam. Particularly, the power-assist mechanism 200 includes aslide shaft 201 fixed to the secondpressing plate 103, afirst cam plate 202, asecond cam plate 203, aball plate 204, and acoil spring 205 that biases thesecond cam plate 203 in a direction which separates thesecond cam plate 203 from thefirst cam plate 202. Asupport plate 250 that supports thecoil spring 205 by abutting a right portion of thecoil spring 205 is fixed onto a terminal side of theslide shaft 201. It is to be noted that the power-assist mechanism 200 is not limited to the ball cam structure and may be configured as any other appropriate structure as long as the power-assist mechanism is configured to reduce the force required to disengage theclutch 2. - A
retainer 84 is arranged on a right end of thehousing body 46 c. As shown inFIG. 6 a, theretainer 84 is shaped to be fitted into an outer hull of thehousing body 46 c. In the present embodiment, theclutch housing 46 is cylindrical. Due to this, theretainer 84 is ring-shaped. Theretainer 84 includes mount holes 84 a. Thearms 46 d (seeFIGS. 3 and 4 ) of thehousing body 46 c are fitted into the mount holes 84 a. - A
stopper 84 c (FIGS. 6 a-6 b) is provided on theretainer 84 along the inner circumference of theretainer 84. Thestopper 84 c is shaped so that the inner circumference of the circular portion of theretainer 84 includes a shoulder protruding from the front surface as shown in reference toFIG. 6 b andFIG. 8 (e.g., the left direction inFIG. 6 b and the right direction inFIG. 8 ). -
FIG. 5 a is a front plan view ofcirclip 85 according to the present embodiment. Thecirclip 85 has a notched ring shape configured to lock theretainer 84 onto thehousing body 46 c. Thecirclip 85 includes slit or notchedportion 85 b as depicted in reference toFIG. 5 a. - As shown in
FIGS. 7 and 8 , theretainer 84 is locked to thearms 46 d by thecirclip 85. Thecirclip 85 is fitted into agroove 46 e provided in eacharm 46 d on the inner periphery of thehousing body 46 c (seeFIG. 4 ). Theretainer 84 is locked to thearms 46 d and supports an outer side end 83 a of thedisc spring 83. Theroller retainer 78 supports aninner side end 83 b of thedisc spring 83 as shown inFIG. 8 . Theretainer 84 experiences a reaction force to the biasing force of thedisc spring 83 against eachroller weight 41, with the force being applied from left to right inFIG. 8 . Thecirclip 85 is fitted into thecirclip groove 46 e so as to prevent detachment of theretainer 84 from thehousing body 46 c by this reaction force. Further, by fitting thecirclip 85 into thecirclip groove 46 e, thecirclip 85 restricts movement of at least thepressure plate 77 and the roller weight 41 (among constituent elements of the clutch 2) in the axial direction of the main shaft 33 (seeFIG. 3 ). Due to this, it is possible to ensure that thepressure plate 77 receives the centrifugal force of eachroller weight 41 generated by rotation ofclutch housing 46. - Moreover, as shown in
FIGS. 7 and 8 , thecirclip 85 is suppressed from deforming radially inward by thestopper 84 c provided on theretainer 84. The height of thestopper 84 c (when viewed in the crosswise direction inFIG. 6 b) is not limited to a specific value and may be set to any height capable of suppressing the radial inward deformation of thecirclip 85 during actuation of thepower unit 3 so as to prevent detachment of thecirclip 85. - By way of example, the
circlip 85 locks theretainer 84 and is fitted into thehousing body 46 c in the following order. In the clutch 2 shown inFIG. 3 , in a state in which a region surrounded by theclutch housing 46 is accessible (a state in which theclutch cover 31 is detached and in which the power-assist mechanism 200 is not mounted inFIG. 3 ), thearms 46 d of theclutch housing 46 are inserted into the mount holes 84 a of theretainer 84. After inserting theretainer 84 onto thearms 46 d, theslide shaft 201 is rotated in a predetermined direction by a tool such as a driver to allow thepressure plate 77 to press-contact theplate group 66. By forcibly applying the pressing force against theplate group 66 to thepressure plate 77 from outside of the clutch 2, the reaction force (to the biasing force of thedisc spring 83 against each roller weight 41) experienced by theretainer 84 is eliminated. - After allowing the
pressure plate 77 to press theplate group 66, the outer diameter of thecirclip 85 is reduced to be smaller than the inner diameter of thecirclip groove 46 e. The outer diameter of thecirclip 85 is reduced by compressing thecirclip 85 until contact occurs between left and right terminal ends of thecirclip 85 which are normally separated from each other by the slit or notchedportion 85 b, as shown inFIG. 5 . The reducedcirclip 85 is fitted into thecirclip groove 46 e. - The outer circumference side of the
circlip 85 is fitted into thecirclip groove 46 e. Further, even if the diameter of thecirclip 85 is reduced during actuation of thepower unit 3, the inner arcuate surface of thecirclip 85 would be contacted by thestopper 84 c. Due to this, reduction of the inner diameter of thecirclip 85 is restricted. In other words, the inner diameter of thecirclip 85 is hardly reduced during actuation of thepower unit 3. It is, therefore, possible to prevent detachment of thecirclip 85 from thearms 46 d by providing thestopper 84 c on theretainer 84. -
Circlip 85 ofFIG. 5( a) may also be utilized in a first modification of the above-described embodiment. Further, as shown inFIGS. 9 a and 9 b,pin stoppers 94 b are provided in a circular fashion on aretainer 94 according to the first modification. Thepin stoppers 94 b are ribs formed on a front surface of theretainer 94. As shown inFIGS. 10 and 11 , theretainer 94 is locked to thearms 46 d by thecirclip 85. Thecirclip 85 is suppressed from deforming radially inward by thestoppers 94 b provided on theretainer 94. The number of thestoppers 94 b and spacing intervals thereof are not limited specifically. Further, the height of each of thestoppers 94 b (when viewed in the crosswise direction inFIG. 9 b) is not limited to a specific value and may be set to any height capable of suppressing the radial inward deformation of thecirclip 85 so as to prevent detachment of thecirclip 85 during actuation of apower unit 3. - It is to be noted that the manner of forming the stoppers 84 b is not limited to forming of ribs on the surface of the
retainer 84. For example, commonly used screws may be screwed into screw holes (not shown) provided in theretainer 84 with the heads of the screws which remain on the surface of theretainer 84 being used as the stoppers, respectively. -
Circlip 85 ofFIG. 5( a) may also be utilized in a second modification of the above-described first embodiment. Thecirclip 85 used in the second modification is similar to thecirclip 85 used in the first modification. Further, as shown inFIGS. 12 a and 12 b, astopper 104 d is provided in one portion of anannular retainer 104. Thestopper 104 d is a rib formed on a front surface of theretainer 104. As shown inFIGS. 13 and 14 , theretainer 104 is locked toarms 46 d by thecirclip 85. Thecirclip 85 is suppressed from deforming radially inward by thestopper 104 d (provided on the retainer 104) andhousing body 46 c. The position of thestopper 104 d is not limited to a specific position on the annular portion of the front surface of theretainer 104. The position of thestopper 104 d may be set to a position capable of suppressing the radial inward deformation of thecirclip 85 so as to prevent the detachment of thecirclip 85 during actuation ofpower unit 3. - It is to be noted that the manner of forming the
stopper 104 d is not limited to forming a rib on the front surface of theretainer 104. For example, a commonly used bolt may be screwed into a bolt hole (not shown) provided on the outer surface of the annular portion of theretainer 104 with the head of the bolt, which remains on the surface of theretainer 84, being used as a stopper. - As stated so far, the clutch 2 according to the first embodiment can suppress the radially inward deformation of the
circlip 85 during driving of theengine 4. By suppressing the radially inward deformation of thecirclip 85, detachment of thecirclip 85 from theclutch housing 46 can be prevented. - The clutch 2 according to the first embodiment includes a stopper suppressing the radially inward deformation of the
circlip 85. The stopper suppressing the radially inward deformation of thecirclip 85 is thestopper 84 c,stoppers 94 b or thestopper 104 d provided on the surface of theretainer 84, theretainer 94 and theretainer 104, respectively. Thecirclip 85 is suppressed from deforming radially inward by the stopper during driving of theengine 4. It is, therefore, possible to prevent detachment of thecirclip 85 from theclutch housing 46. Furthermore, if one of thestoppers retainer 84, theretainer 94 and theretainer 104, respectively, the position of thecirclip 85 in thehousing body 46 c can be held and thecirclip 85 can be prevented from detaching from thearms 46 d without increasing the number of components related to theclutch 2. - The clutch 2 according to the present embodiment is a centrifugal friction clutch. The
clutch 2 includes thecentrifugal weights 41 and theroller retainer 78. Each of thecentrifugal weights 41 receives a centrifugal force by rotation of theclutch housing 46 and moves radially outward from the axis of themain shaft 33. Each of the cam surfaces 81, which are provided on thepressure plate 77, restricts movement of one of thecentrifugal weights 41 in the centrifugal direction and converts the centrifugal force into a force in the axial direction of themain shaft 33. Theroller retainer 78 stops movement of thecentrifugal weight 41 in the axial direction and supports theinner side end 83 b of thedisc spring 83. Further, theretainer 84 supports the outer side end 83 a of thedisc spring 83. By supporting the outer side end 83 a of thedisc spring 83, theretainer 84 receives the biasing force of thedisc spring 83. Due to this, in thecentrifugal friction clutch 2 according to the present embodiment, the biasing force of thedisc spring 83 loaded onto theretainer 84 is greater than when compared with a non-centrifugal friction clutch. Moreover, thecirclip 85 locks theretainer housing body 46 c. Therefore, the clutch 2 according to the first embodiment exhibits a greater advantage of preventing the detachment of thecirclip 85 than that of the non-centrifugal friction clutch. - The clutch 2 according to the present embodiment is a multiple-disc friction clutch. The
clutch 2 includes a plurality offriction plates 64 supported on theclutch housing 46 and a plurality ofclutch plates 65 supported on theclutch boss 48. The plurality offriction plates 64 and the plurality ofclutch plates 65 are alternately arranged in a predetermined direction. Further, thepressure plate 77 forces thefriction plates 64 to make contact with theclutch plates 65 by moving in the predetermined direction. Thedisc spring 83 applies a (biasing) force assisting in making the contact between thefriction plates 64 and theclutch plates 65. Theretainer 84 receives the biasing force of thedisc spring 83 by supporting the outer side end 83 a of thedisc spring 83. Thedisc spring 83 needs a greater biasing force than that in a friction clutch that is not of the multiple-disc type having a plurality of pairs offriction plates 64 andclutch plates 65. Due to this, in the multiple-disc friction clutch according to the present embodiment, the biasing force of thedisc spring 83 loaded onto theretainer 84 is greater than that in the friction clutch that is not of the multiple-disc type. Further, thecirclip 85 locks theretainer 84 by being fitted into thehousing body 46 c. Therefore, the clutch 2 according to the present embodiment exhibits a greater advantage of preventing detachment of thecirclip 85 than that of the friction clutch that is not of the multiple-disc type. - The clutch 2 according to the first embodiment includes the power-
assist mechanism 200. By including the power-assist mechanism 200 in a large-capacity clutch such as theclutch 2, it is possible to facilitate disengaging the clutch 2 by the clutch lever 24 (FIG. 1 ). Namely, as compared with a clutch that does not include the power-assist mechanism 200, the force required to disengage the clutch can be reduced. In other words, the power-assist mechanism 200 is provided in the clutch so as to reduce the force required to manipulate the large-capacity clutch. In the clutch 2 according to the embodiment, the diameter of each of the plates, for example, thefriction plates 64 and theclutch plates 65, as related to disengagement of the clutch 2 is larger than that of each of plates in a small-capacity clutch. Accordingly, the diameter of theclutch housing 46 covering up thefriction plates 64 and theclutch plates 65 is larger than that in the small-capacity clutch. Moreover, thedisc spring 83 applies the force assisting in the contact between thefriction plates 64 and theclutch plates 65. Due to this, thedisc spring 83 needs a greater biasing force than that in the small-capacity clutch. - The
retainer 84 receives the reaction force to the biasing force of thedisc spring 83 by supporting the outer side end 83 a of thedisc spring 83. Thecirclip 85 locks theretainer 84 by being fitted into thearms 46 d of thehousing body 46 c. In the large-diameter clutch, the inner diameter of thecirclip 85 is large compared with the small-diameter clutch. Due to this, during actuation of thepower unit 3, a greater centrifugal force is generated on theentire circlip 85 than in the small-capacity clutch. If a relatively great centrifugal force is generated on theentire circlip 85, a greater frictional force is generated between the outer circumferential side of thecirclip 85 and the inner hull of thehousing body 46 c. If such a relatively great frictional force is dropped instantaneously, the probability of deforming the circular portion of thecirclip 85 increases. If thecirclip 85 deforms, thecirclip 85 may possibly detach from thehousing body 46 c. Therefore, the clutch 2 according to the present embodiment exhibits the advantage of being more capable of preventing the detachment of thecirclip 85 than that of the small-capacity clutch. - The clutch 2 according to the embodiment can be used in a vehicle. The vehicle including the clutch 2 can run stably in various running conditions because the detachment of the
circlip 85 is prevented. - Moreover, the clutch 2 according to the present embodiment can be used in a motorcycle. The motorcycle often requires complicated throttle operation as compared with other types of vehicles. Further, during running, the
engine 4 is driven at higher engine speed than that of the engine of the other types of vehicles. Due to this, themain shaft 33 of the clutch 2 is driven at a higher rotational speed. A greater centrifugal force is generated on thecirclip 85 fitted into theclutch housing 46 by driving at the higher engine speed. If a relatively great centrifugal force is generated on theentire circlip 85, a greater frictional force is generated between the outer circumferential side of thecirclip 85 and the inner hull of thehousing body 46 c. If such a relatively great frictional force is dropped instantaneously, the probability of deforming the circular portion of thecirclip 85 increases. If thecirclip 85 deforms, thecirclip 85 may possibly detach from thehousing body 46 c. Therefore, the clutch 2 according to the embodiment exhibits the greater advantage of preventing the detachment of thecirclip 85 by being included in the motorcycle 1. - In the previous embodiment, at least one stopper is provided on the retainer as means for suppressing the radially inward deformation of the
circlip 85. However, the means for suppressing the radially inward deformation of thecirclip 85 is not necessarily limited to a structure provided on theretainer 84. For example, as shown below, thecirclip 85 may also be structured to suppress the radially inward deformation of thecirclip 85. - As shown in
FIGS. 16 a and 16 b, acirclip 95 is substantially ring-shaped so as to lock a retainer 304 (FIGS. 15 a and 15 b) tohousing body 46 c.Circlip 95 is provided with a slit or notchedportion 95 a as depicted inFIG. 16 a. The shape and angular inclination of theslit 95 a are not limited specifically as long as the annular portion of thecirclip 95 is broken in one portion. InFIG. 16 a, theslit 95 a bisects the annular portion ofcirclip 95 at a right angle to the outer circumference of thecirclip 95. A width W of theslit 95 a, as shown inFIG. 16 a, is smaller than the difference in length between the outer radius and the inner radius of thecirclip 95. In other words, the width W satisfies the relationship T<(D1−D2)/2, wherein the outer diameter of thecirclip 95 is designated D1, the inner diameter thereof is designated D2, and T stands for the width W of theslit 95 a. - As shown in
FIGS. 15 a and 15 b, theretainer 304 has such a shape as to be fitted into an outer hull of thehousing body 46 c. In this embodiment, aclutch housing 46 has a cylindrical shape. Due to this, theretainer 304 has an annular shape. Mount holes 304 a are formed in theretainer 304 andarms 46 d (seeFIGS. 3 and 4 ) of thehousing body 46 c are fitted into the mount holes 304 a. - As shown in
FIGS. 17 and 18 , theretainer 304 is locked to thearm 46 d by thecirclip 95. Acirclip groove 46 e, into which the outer circumferential side of thecirclip 95 is fitted, is provided in each of thearms 46 d on an inner periphery of thehousing body 46 c (seeFIG. 4 ). Theretainer 304 is locked to thearms 46 d and supports the outer side end 83 a ofdisc spring 83.Roller retainer 78 supports theinner side end 83 b of thedisc spring 83, as stated above. Theretainer 304 experiences a reaction force to the biasing force of thedisc spring 83 against eachroller weight 41, with the force being applied from left to right inFIG. 18 . Thecirclip 95 is fitted into thecirclip groove 46 e so as to prevent detachment of theretainer 304 from thehousing body 46 c by this reaction force. Further, by fitting thecirclip 95 into thecirclip groove 46 e, thecirclip 95 restricts movement of at least thepressure plate 77 and the roller weight 41 (among constituent elements of the clutch 2) in the axial direction of the main shaft 33 (seeFIG. 3 ). Due to this, it is possible to ensure that thepressure plate 77 receives the centrifugal force of eachroller weight 41 generated by rotation ofclutch housing 46. - By way of example, the
circlip 95 locks theretainer 304 and is fitted into thehousing body 46 c in the following order. In the clutch 2 shown inFIG. 3 , in a state in which a region surrounded by theclutch housing 46 is accessible (a state in which theclutch cover 31 is detached and in which the power-assist mechanism 200 is not mounted inFIG. 3 ), thearms 46 d of theclutch housing 46 are inserted into the mount holes 304 a of theretainer 304. After inserting theretainer 304 onto thearms 46 d, theslide shaft 201 is rotated in a predetermined direction by a tool such as a driver to allow thepressure plate 77 to press-contact theplate group 66. By forcibly applying the pressing force against theplate group 66 to thepressure plate 77 from outside of the clutch 2, the reaction force (to the biasing force of thedisc spring 83 against each roller weight 41) experienced by theretainer 304 is eliminated. - After allowing the
pressure plate 77 to press theplate group 66, the outer diameter of thecirclip 95 is reduced to be smaller than the inner diameter of thecirclip groove 46 e. The outer diameter of thecirclip 95 is reduced by compressing thecirclip 95 to cross the left and right terminal ends, which are normally separated by slit 95 a as shown inFIG. 16 a, with each other. The reducedcirclip 95 is fitted into thecirclip groove 46 e. - In the
circlip 95 with the reduced outer diameter, the crossing portions overlap each other on front and rear surfaces of the sheet ofFIG. 16 (i.e., crosswise inFIGS. 3 and 4 ). A portion in which the left and right terminal ends of thecirclip 95 overlap each other has a thickness that is twice or more as large as that of other portions of thecirclip 95. Due to this, one of thecirclip grooves 46 e has a width twice or more as large as that of theother circlip grooves 46 e in one of the portions and regions of the plurality ofarms 46 d so that the portion in which the left and right terminal ends of thecirclip 95 overlap each other can be fitted into thehousing body 46 c. The portion and region in which the twice or more width is set are not limited to a specific one of thearms 46 d as long as thecirclip 95 does not detach during actuation ofpower unit 3. - Even if the inner diameter of the
circlip 95 is reduced during actuation of thepower unit 3, the left and right terminal ends of thecirclip 95 can contact each other in the area defined by theslit 95 a. Namely, even if the inner diameter of thecirclip 95 is to be reduced, the inner diameter is hardly reduced during actuation of thepower unit 3 since both terminal ends of thecirclip 95 across theslit 95 a abut on each other. Therefore, it is possible to prevent detachment of thecirclip 95 from thearms 46 d by providing theslit 95 a in thecirclip 95. - The clutch 2 according to the second embodiment is configured to suppress the radially inward deformation of the
circlip 95. Examples of a configuration for suppressing the radially inward deformation of thecirclip 95 include theslit 95 a formed by bisecting theannular circlip 95. By providing theslit 95 a, the left and right terminal ends of thecirclip 95 can contact each other in the area defined by the slit or notchedportion 95 a even if the inner diameter of thecirclip 95 is to be reduced whileengine 4 is being driven. Namely, even if the inner diameter of thecirclip 95 is to be reduced, both terminal ends of thecirclip 95 abut on each other in the slit or notchedportion 95 a. Due to this, the inner diameter of thecirclip 95 is hardly reduced during actuation of thepower unit 3. It is, therefore, possible to prevent detachment of thecirclip 95 from theclutch housing 46. - It is to be clearly understood that the above description was made only for purposes of an example and not as a limitation on the scope of the invention as claimed herein below.
Claims (21)
1. A friction clutch transmitting a drive force of an engine, the friction clutch comprising:
a clutch housing adapted to be driven to rotate by the engine, the clutch housing including a first plate;
a clutch boss including a second plate, the second plate being operatively disposed relative to the first plate in a predetermined direction;
a pressure plate arranged to rotate with the clutch housing, the pressure plate configured to press the first plate into the second plate by moving in the predetermined direction;
a clutch spring operatively coupled to the pressure plate and applying a biasing force via the pressure plate in a direction of causing the first plate and the second plate to contact each other;
a retainer having a substantially circular shape mounted onto the clutch housing away from the pressure plate and receiving a reaction force to the biasing force of the clutch spring by supporting one end of the clutch spring opposite the pressure plate; and
a retaining ring having a substantially annular shape with a notch extending therethrough in a radial direction, the retaining ring being fitted into an inner peripheral side of the clutch housing and configured to secure the mounted retainer on the clutch housing; wherein
the retainer ring is arranged within the clutch to be suppressed from deforming radially inward.
2. The friction clutch of claim 1 , wherein the secured retainer is configured to suppress the retaining ring from being deformed radially inward.
3. The friction clutch of claim 2 , wherein the retainer includes at least one stopper configured to suppress the retaining ring from deforming radially inward within the clutch housing.
4. The friction clutch of claim 3 , wherein the at least one stopper is a member abutting on a radially inward side of the retaining ring.
5. The friction clutch of claim 3 , wherein the at least one stopper is an integral part of the retainer.
6. The friction clutch of claim 3 , wherein the at least one stopper member is operatively disposed within the notch of the retaining ring.
7. The friction clutch of claim 1 , wherein a width of the notched portion of the retaining ring is smaller than the difference in length between the outer radius and the inner radius of the retaining ring.
8. The friction clutch of claim 1 , further comprising a roller weight that moves radially outward within the clutch housing under a centrifugal force generated during rotation of the clutch housing, the roller weight increasing the force by which the pressure plate presses the first plate into the second plate as it moves outward in the radial direction.
9. The friction clutch of claim 9 , further comprising a roller retainer operatively coupled between the roller weight and the clutch spring.
10. The friction clutch of claim 9 , wherein the roller retainer supports the other end of the clutch spring.
11. The friction clutch of claim 9 , wherein the roller retainer is coupled to the clutch housing.
12. The friction clutch of claim 1 , further comprising a power-assist mechanism which receives torque from the pressure plate and converts the torque into a force for moving the pressure plate in a direction of separating the first plate from the second plate for clutch disengagement.
13. A vehicle comprising the friction clutch of claim 1 , wherein the friction clutch disengageably transmits a drive force from the engine toward a driving wheel.
14. A motorcycle comprising the friction clutch of claim 1 .
15. The friction clutch of claim 8 , wherein the retaining ring restricts movement of the pressure plate and the roller weight in the axial direction of a main shaft, the main shaft extending through the clutch housing.
16. The friction clutch of claim 1 , wherein the retaining ring is configured as a circlip.
17. The friction clutch of claim 1 , wherein the retainer includes a plurality of pin stopper members.
18. The friction clutch of claim 17 , wherein the pin stopper members are provided in a substantially circular fashion on the outer surface of the retainer.
19. The friction clutch of claim 17 , wherein the pin stopper members are configured as ribs formed on the outer surface of the retainer.
20. The friction clutch of claim 17 , wherein the retaining ring is suppressed from deforming radially inward by the stopper members.
21. The friction clutch of claim 6 , wherein the at least one stopper is configured as a rib formed on the outer surface of the retainer.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008-043510 | 2008-02-25 | ||
JP2008043510A JP2009197991A (en) | 2008-02-25 | 2008-02-25 | Friction clutch |
Publications (1)
Publication Number | Publication Date |
---|---|
US20090211864A1 true US20090211864A1 (en) | 2009-08-27 |
Family
ID=40672544
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/392,323 Abandoned US20090211864A1 (en) | 2008-02-25 | 2009-02-25 | Friction clutch |
US12/392,440 Expired - Fee Related US8381891B2 (en) | 2008-02-25 | 2009-02-25 | Friction clutch |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/392,440 Expired - Fee Related US8381891B2 (en) | 2008-02-25 | 2009-02-25 | Friction clutch |
Country Status (3)
Country | Link |
---|---|
US (2) | US20090211864A1 (en) |
EP (1) | EP2093445B1 (en) |
JP (1) | JP2009197991A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090211868A1 (en) * | 2008-02-25 | 2009-08-27 | Yamaha Hatsudoki Kabushiki Kaisha | Motorcycle including centrifugal clutch |
US20210231155A1 (en) * | 2018-05-07 | 2021-07-29 | Schaeffler Technologies AG & Co. KG | Arrangement for securing at least one circlip against centrifugal force, which circlip is axially fastened on a rotor shaft of an electrical machine for positional securing, and use of an arrangement of this type |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3155715U (en) * | 2008-10-10 | 2009-11-26 | ヤマハ発動機株式会社 | Friction clutch and vehicle equipped with the same |
JP5171778B2 (en) * | 2009-09-30 | 2013-03-27 | 本田技研工業株式会社 | Multi-plate clutch device |
US8932169B2 (en) * | 2013-01-04 | 2015-01-13 | Gm Global Technology Operations, Llc | Clutch backing plate with fluid drain |
WO2022176693A1 (en) * | 2021-02-18 | 2022-08-25 | ヤマハ発動機株式会社 | Centrifugal clutch and straddle-type vehicle |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3265172A (en) * | 1963-04-26 | 1966-08-09 | Suzuki Motor Co | Cushioned torque-limiting centrifugal clutch |
DE2508677C3 (en) * | 1975-02-28 | 1979-05-10 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Snap ring lock |
JPS524955A (en) * | 1975-06-30 | 1977-01-14 | Katsuhiko Araki | Booster for the clutch |
AT398811B (en) * | 1987-02-05 | 1995-02-27 | Hoerbiger Ventilwerke Ag | COMPRESSOR UNIT WITH A SCREW COMPRESSOR |
US5201233A (en) * | 1992-01-29 | 1993-04-13 | General Motors Corporation | Retainer assembly with dished retaining ring |
JP3381442B2 (en) * | 1995-02-24 | 2003-02-24 | スズキ株式会社 | Power assist device for vehicle clutch mechanism |
JP4198385B2 (en) * | 2002-04-26 | 2008-12-17 | スズキ株式会社 | Multi-plate automatic centrifugal clutch device |
DE102005048198B4 (en) * | 2005-10-07 | 2007-06-06 | Albrecht Knecht | snap ring |
-
2008
- 2008-02-25 JP JP2008043510A patent/JP2009197991A/en active Pending
-
2009
- 2009-02-19 EP EP09250432.3A patent/EP2093445B1/en not_active Not-in-force
- 2009-02-25 US US12/392,323 patent/US20090211864A1/en not_active Abandoned
- 2009-02-25 US US12/392,440 patent/US8381891B2/en not_active Expired - Fee Related
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090211868A1 (en) * | 2008-02-25 | 2009-08-27 | Yamaha Hatsudoki Kabushiki Kaisha | Motorcycle including centrifugal clutch |
US8037985B2 (en) * | 2008-02-25 | 2011-10-18 | Yamaha Hatsudoki Kabushiki Kaisha | Motorcycle including centrifugal clutch |
US20210231155A1 (en) * | 2018-05-07 | 2021-07-29 | Schaeffler Technologies AG & Co. KG | Arrangement for securing at least one circlip against centrifugal force, which circlip is axially fastened on a rotor shaft of an electrical machine for positional securing, and use of an arrangement of this type |
US11939998B2 (en) * | 2018-05-07 | 2024-03-26 | Schaeffler Technologies AG & Co. KG | Arrangement for securing at least one circlip against centrifugal force, which circlip is axially fastened on a rotor shaft of an electrical machine for positional securing, and use of an arrangement of this type |
Also Published As
Publication number | Publication date |
---|---|
EP2093445A3 (en) | 2013-04-10 |
US20090250304A1 (en) | 2009-10-08 |
JP2009197991A (en) | 2009-09-03 |
EP2093445A2 (en) | 2009-08-26 |
EP2093445B1 (en) | 2014-10-29 |
US8381891B2 (en) | 2013-02-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8210333B2 (en) | Clutch and vehicle having clutch | |
US9631679B2 (en) | Multiple plate clutch | |
US8381891B2 (en) | Friction clutch | |
US8695775B2 (en) | Centrifugal clutch and vehicle provided with the same | |
EP2063141B1 (en) | Vehicle with friction clutch | |
US8037985B2 (en) | Motorcycle including centrifugal clutch | |
US8317009B2 (en) | Centrifugal multi-plate friction clutch and vehicle equipped with the same | |
US8210334B2 (en) | Motorcycle with centrifugal clutch | |
JP5286101B2 (en) | Friction clutch and vehicle equipped with the same | |
JP3155715U (en) | Friction clutch and vehicle equipped with the same | |
EP2063142B1 (en) | Friction clutch | |
US8256597B2 (en) | Friction clutch and vehicle equipped with the same | |
EP2211068B1 (en) | Clutch for automatically adjusting play amount and vehicle including the same | |
US7963381B2 (en) | Multi-plate centrifugal clutch and vehicle equipped with the same | |
US7665592B2 (en) | Centrifugally assisted clutch | |
JP4691929B2 (en) | Back torque reduction device | |
JP2009030792A (en) | Centrifugal clutch and vehicle having the same | |
JP2009144913A (en) | Friction clutch and vehicle equipped with the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: EXPRESSLY ABANDONED -- DURING EXAMINATION |