CN112739615B

CN112739615B - Power unit for saddle-ride type vehicle

Info

Publication number: CN112739615B
Application number: CN201980062044.8A
Authority: CN
Inventors: 国石贤; 岩崎崇生; 阿藤绅司; 久我信二
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2018-09-25
Filing date: 2019-09-20
Publication date: 2022-09-27
Anticipated expiration: 2039-09-20
Also published as: JP7130053B2; CN112739615A; PH12021550618A1; BR112021003673A2; WO2020066879A1; JPWO2020066879A1

Abstract

A power unit for a saddle-ride type vehicle is provided with: an alternator (54) having a rotor (72), the rotor (72) being coupled to the crankshaft on the outside of the crankcase (38) and rotating about the axis of rotation (Rx) of the crankshaft; and case covers (55, 57) that cover the crankcase (38) from the outside and house the alternator (54). An air discharge passage (99) is formed between the crankcase (38) and the case cover (57), and the air discharge passage (99) extends rearward from an air discharge opening (98) defined by a peripheral wall (81a) surrounding the alternator (54) relative to a step plate provided on the vehicle body. Thus, a power unit for a saddle-ride type vehicle is provided, in which the feet of the driver are not exposed to warm air from an alternator.

Description

Power unit for saddle-ride type vehicle

Technical Field

The present invention relates to a power unit for a saddle-ride type vehicle, the power unit comprising: a crankcase which rotatably supports a crankshaft; an alternator having a rotor coupled to the crankshaft on an outer side of the crankcase and rotating around a rotation axis of the crankshaft; and a case cover which covers the crankcase from the outside and houses the alternator.

Background

Patent document 1 discloses an ACG (alternator) starter that generates electric power in accordance with rotation of a crankshaft and causes rotation of the crankshaft in accordance with supply of electric current. The ACG starter includes a rotor (rotating body) that is fixed to the crankshaft on the outside of the crankcase and surrounds the stator around the rotation axis. An ACG cover (rotor cover) that surrounds the rotor around the rotation axis and forms a rotor housing space is coupled to the crankcase.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6182099

Disclosure of Invention

Problems to be solved by the invention

In the ACG cover, a notch is formed in a peripheral wall surrounding the ACG below a horizontal plane including the rotation axis. The notch is used to provide an external air communication port. The cooling air of the ACG flows into the housing space from the front, and then flows out from the external air communication port to the outside. The cooling air is directly diffused as warm air from the outside air communication port to the outside air. In particular, since the external air communication port is disposed in front of the driver's step plate, the driver's feet are exposed to warm air.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a power unit for a saddle-ride type vehicle that does not expose the feet of the driver to warm air from an alternator.

Means for solving the problems

According to a first aspect of the present invention, a power unit for a saddle-ride type vehicle includes: the disclosed device is provided with: a crankcase which rotatably supports a crankshaft; an output shaft supported by the crankcase and outputting a rotational force of the crankcase via a transmission; an alternator having a rotor coupled to the crankshaft on an outer side of the crankcase and rotating around a rotation axis of the crankshaft; a case cover that covers the crankcase from the outside and houses the alternator; wherein an air discharge passage is formed between the crankcase and the case cover, the air discharge passage extending rearward from an air discharge port defined by a peripheral wall surrounding the alternator with respect to a step plate provided on a vehicle body, and the case cover has a partition wall partitioning the air discharge passage from a space accommodating a sprocket that transmits a rotational force of the output shaft to a rear wheel.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the output shaft is supported rotatably around an axis parallel to the rotation axis in the rear of the crankshaft by the crankcase, the sprocket is fixed to the output shaft outside the crankcase, is covered by the case cover in the rear of the alternator, and transmits the rotational force of the output shaft to a rear wheel via a winding chain, and the case cover includes: a generator cover that covers the alternator and has the peripheral wall; and a sprocket cover disposed behind the generator cover and covering the sprocket.

According to a third aspect, in addition to the structure of the first or second aspect, the air discharge passage extends toward the rear of the vehicle body at a position below the sprocket.

According to a fourth aspect, in any one of the first to third aspects, the discharge air passage extends downstream in a rotational direction of the rotor along a tangential direction of a cylindrical surface surrounding the rotor coaxially with the rotor.

According to a fifth aspect of the present invention, in the structure of the fourth aspect, the outlet of the air discharge passage is located at a position lower than a rear seat step plate provided on the vehicle body, further to the rear than the step plate.

According to a sixth aspect of the present invention, in the structure of the fifth aspect, the air discharge passage is inclined so as to be lowered toward the ground as it goes toward the rear of the vehicle body.

According to a seventh aspect, in addition to the structure of any one of the first to sixth aspects, the alternator functions as a starter that generates a driving force that causes rotation of the crankshaft at the time of startup of the vehicle.

According to an eighth aspect, in addition to any one of the structures of the first to seventh aspects, on the rotor, a blade is mounted that generates an air flow in a centrifugal direction when the rotor rotates.

According to a ninth aspect, in addition to any one of the configurations of the first to eighth aspects, the box cover is made of resin.

According to a tenth aspect, in the structure of any one of the first to ninth aspects, the tank cover has a water blocking wall that contacts the crankcase on a mating face formed by a plane orthogonal to the rotation axis, protrudes from an outer periphery of the mating face, and covers an outer surface of the crankcase.

According to an eleventh aspect, in the tenth aspect, the water blocking wall is disposed forward and upward of the rotation axis.

According to a twelfth aspect of the present invention, in any one of the first to eleventh aspects, the outlet of the air discharge passage is opposed to a coupler fixed to an engine hanger formed in the crankcase and coupled to a body frame of a vehicle.

Effects of the invention

According to the first aspect, the cooling air of the alternator flows out from the air outlet opening in the peripheral wall surrounding the alternator, and is guided to the rear of the step plate along the air outlet passage. Since the warm air is discharged from the rear of the step plate, the path of the warm air can be kept away from the feet of the driver. The feet of the driver may not be exposed to warm air from the alternator. Further, since the partition wall of the sprocket cover prevents the discharge air from entering toward the sprocket, the sprocket can be protected from the accumulation of dust contained in the discharge air.

According to the second aspect, since the case cover is formed by the generator cover and the sprocket cover, the degree of freedom in the shapes of the generator cover and the sprocket cover at the time of forming is increased. As a result, the degree of freedom of the arrangement of the air discharge passage can be improved.

According to the third aspect, the discharge air can be discharged downward as much as possible. Therefore, the influence of the discharge air on the occupant can be avoided as much as possible.

According to the fourth aspect, since the discharge air passage extends in the direction of the air pushed out by the rotational operation of the rotor, the discharge air can be efficiently introduced from the housing space of the rotor into the discharge air passage.

According to the fifth aspect, the discharged air is discharged from a position lower than the feet of the rear seat occupant mounted on the rear seat footboard, so that the influence of the discharged air on the feet of the rear seat occupant can be suppressed (or avoided).

According to the sixth aspect, since the discharge air has directivity toward the rear lower side, the influence of the discharge air on the driver and the rear seat passenger can be suppressed (avoided).

According to the seventh aspect, since the alternator also functions as a starter, heat is easily given as compared with the case of having only a power generation function. Even in such a case, since the alternator is effectively cooled by the action of the exhaust passage, heat generation of the alternator can be effectively suppressed.

According to the eighth aspect, since the airflow is generated in accordance with the rotation of the blade, the cooling air can efficiently flow into the housing space of the alternator. The heat generation of the alternator can be effectively suppressed.

According to the ninth aspect, since the box cover is made of resin, the box cover generally has a lower thermal conductivity than a metal box cover, and the temperature increase of the box cover can be effectively suppressed. Further, the resin case cover is lighter in weight than the metal case cover, and therefore the resin case cover can contribute to weight reduction of the vehicle.

According to the tenth aspect, when the housing space of the alternator is submerged by water, water that spreads in the centrifugal direction from the rotor enters between the crankcase and the case cover at the mating surface. At this time, the water flowing along the mating surface is blocked by the water blocking wall, so that the water can be prevented from directly scattering from the mating surface to the occupant.

According to the eleventh aspect, the water is prevented from spreading around the case cover in front of and above the rotational axis, but the water can efficiently leak from the mating surfaces of the crankcase and the case cover in the rear of and below the rotational axis. Thus, drainage can be promoted from the storage space of the alternator.

According to the twelfth aspect, since the obstacle faces the outlet of the exhaust passage, the entry of the dust into the exhaust passage can be suppressed.

Drawings

Fig. 1 is a side view schematically showing an entire image of a motorcycle (saddle type vehicle) according to an embodiment of the present invention. (first embodiment)

Fig. 2 is a front view of the motorcycle. (first embodiment)

Fig. 3 is a cross-sectional view of the power unit viewed in a cross-sectional plane including the cylinder axis, the rotation axis of the crankshaft, the shaft center of the main shaft, and the shaft center of the intermediate shaft. (first embodiment)

Fig. 4 is an enlarged left side view of the power unit. (first embodiment)

Fig. 5 is an enlarged vertical sectional view taken along line 5-5 of fig. 4. (first embodiment)

Fig. 6 is an enlarged left side view of the power unit as viewed when the outer member is removed from the inner member.

(first embodiment)

Fig. 7 is an enlarged sectional view taken along line 7-7 of fig. 6. (first embodiment)

Fig. 8 is an enlarged left side view of the power unit as viewed when the AC generator (ACG) cover is removed. (first embodiment)

Fig. 9 is an enlarged perspective view schematically showing an entire image of the inner member of the ACG cover from an obliquely upper viewpoint. (first embodiment)

Description of the reference numerals

11 saddle type vehicle (Motor bicycle)

12 vehicle body frame

32 power unit

34 foot pedal

35 backseat foot pedal

38 crankcase

43c engine hanger

44c connecting piece

45 case cover (left case cover)

54 Alternator (ACG) starter

55 Generator hood (ACG hood)

56 chain wheel

57 sprocket cover

61 crankshaft

72 rotor

72b blade

73 speed variator

76 output shaft (middle shaft)

79 winding chain

81a peripheral wall (inner peripheral wall)

98 air outlet

99 air exhaust passage

99a outlet

101 partition wall

103 mating surface

104 water retaining wall

Axis of rotation of Rx (crankshaft)

WR rear wheel

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Here, the upper, lower, front, rear, left, and right of the vehicle body are defined based on the line of sight of the occupant seated in the motorcycle.

First embodiment

Fig. 1 is an overall image schematically showing a motorcycle as a saddle type vehicle according to an embodiment of the present invention. The motorcycle 11 includes a body frame 12 and a body cover 13 attached to the body frame 12. The vehicle body cover 13 has a box cover 16 that covers the fuel tank 14 and is connected to a passenger seat 15 behind the fuel tank 14. Fuel is stored in the fuel tank 14. When the motorcycle 11 is driven, the occupant gets over the occupant seat 15. The passenger seat 15 can be used for seating a passenger (hereinafter, referred to as a "rear-seat passenger") seated in a rear seat in addition to the driver.

The vehicle body frame 12 includes: a head pipe 17; a main frame 19 extending rearward and downward from the head pipe 17 and having a pivot frame 18 at a rear lower end; a lower frame 21 extending downward from the head pipe 17 at a position below the main frame 19; left and right seat frames 22 extending rearward in the horizontal direction from the curved region 19a of the main frame 19; a rear frame 23 extending rearward and upward from the pivot frame 18 below the seat frame 22 and joined to the seat frame 22 from below at a rear end. The rear frame 23 supports the seat frame 22 from below.

The front fork 24 is rotatably supported by the head pipe 17. A front wheel WF is rotatably supported around an axle 25 on the front fork 24. A steering handle 26 is coupled to an upper end of the front fork 24. As shown in fig. 2, the steering handle 26 extends in the vehicle width direction to the left and right in parallel with the ground. Handlebar grips 27 are fixed to both ends of the steering handlebar 26. The driver grips the handlebar 27 with his or her left or right hand when driving the motorcycle 11.

As shown in fig. 1, a swing arm 29 is coupled to the body frame 12 at the rear of the vehicle, and the swing arm 29 is vertically swingable about a pivot shaft 28. A rear wheel WR is rotatably supported around an axle 31 at the rear end of the swing arm 29. A power unit 32 for generating a driving force to be transmitted to the rear wheel WR is mounted on the vehicle body frame 12 between the front wheel WF and the rear wheel WR. The power of the power unit 32 is transmitted to the rear wheel WR via the power transmission device 33.

The motorcycle 11 includes a pair of pedals 34 disposed on both left and right sides of the power unit 32 in front of the pivot frame 18, and a pair of rear seat pedals 35 disposed behind the pedals 34 and disposed on both left and right sides of the rear wheel WR in front of the axle 31. As shown in fig. 2, the step plates 34 are fixed to both ends of a rod 36 that is attached to the engine 32 from below and extends in the vehicle width direction. The rear seat steps 35 are fixed to brackets 37, respectively, and the brackets 37 extend rearward from the pivot shaft 28, are bent upward in the lateral direction of the rear wheel WR, and are coupled to the rear frame 23 at the upper ends thereof. The driver can place his feet on the step plate 34 across the passenger seat 15. The rear-seat occupant can place his or her feet on the rear-seat footboard 35 across the occupant seat 15 at the rear of the driver.

The power unit 32 includes: a crankcase 38 disposed between the lower frame 21 and the main frame 19, and connected to the lower frame 21 and the main frame 19, respectively; a cylinder block 39 extending upward from the front side of the crankcase 38 and having a cylinder axis C that inclines forward; a cylinder head 41 coupled to an upper end of the cylinder block 39 and supporting a valve train; and a head cover 42 coupled to an upper end of the cylinder head 41 and covering a valve train on the cylinder head 41. The crankcase 38 is formed with two upper and lower engine hangers 43a projecting from the front side to the front side, and two upper and

lower engine hangers

43b, 43c projecting from the rear side to the rear side. The front engine hanger 43a is coupled to the lower frame 21 by a coupling 44a such as a bolt and a nut. The

rear engine hangers

43b and 43c are coupled to the pivot frame 18 by coupling

members

44b and 44c such as bolts and nuts. Power is generated in the crankcase 38 about the axis of rotation Rx. A left case cover 45 that houses an Alternator (ACG) starter and a sprocket described later is coupled to the crankcase 38.

As shown in fig. 3, a cylinder 48 is defined in the cylinder block 39, and the cylinder 48 guides the linear reciprocating motion of the piston 47 along the cylinder axis C. Here, a single cylinder 48 for receiving a single piston 47 is formed on the cylinder block 39. The combustion chamber 49 is divided between the piston 47 and the cylinder head 41. An ignition plug 51 facing the combustion chamber 49 is mounted on the cylinder head 41. The intake valve and the exhaust valve, which are opened and closed by rotation of the camshaft 52, act to introduce the air-fuel mixture into the combustion chamber 49, and exhaust gas after combustion is discharged from the combustion chamber 49.

The crankcase 38 is divided into a first case half body 38a and a second case half body 38 b. The inner surfaces of the first case half body 38a and the second case half body 38b are opposed to each other. The first case half body 38a and the second case half body 38b are joined to each other in a liquid-tight manner at mating surfaces, and cooperate to define the crank chamber 53. The left case cover 45 is composed of an ACG cover (rotor cover) 55 and a sprocket cover 57, the ACG cover 55 is coupled to the outer surface of the first case half body 38a, the ACG actuator 71 is housed between the first case half body 38a, and the sprocket cover 57 is coupled to the outer surface of the first case half body 38a, and the sprocket 56 is housed between the first case half body 38 a. As shown in fig. 2, the ACG cover 55 and the sprocket cover 57 are disposed inside a virtual plane VP connecting the front end of the step plate 34, the front end of the handlebar 27, and the grounding point of the front wheel WF when the bicycle is tilted. As shown in fig. 3, a clutch cover 59 is coupled to an outer surface of the second case half body 38b, and a friction clutch 58, which will be described later, is accommodated between the clutch cover 59 and the second case half body 38 b.

The crankshaft 61 includes

journals

64a and 64b connected to

ball bearings

62 and 63 fitted into the first half case 38a and the second half case 38b, respectively, and a crankshaft 65 disposed between the

journals

64a and 64b and housed in the crank chamber 53. The crank 65 has crank arms 66 integrated with the

journals

64a, 64b, and crank pins 67 connecting the crank arms 66 to each other. The axes of the

journals

64a, 64b coincide with the axis of rotation Rx. A large end of a connecting rod 68 extending from the piston 47 is rotatably connected to the crank pin 67. The connecting rod 68 converts the linear reciprocating motion of the piston 47 into the rotational motion of the crankshaft 61.

An ACG starter 54 is connected to one end of a crankshaft 61 projecting outward in one direction from the crankcase 38. The ACG starter 54 includes a stator 71 fixed to an outer surface of the crankcase 38, and a rotor (rotating body) 72 coupled to one end of the crankshaft 61 protruding from the crankcase 38 so as to be relatively non-rotatable. The stator 71 is arranged in the circumferential direction around the crankshaft 61, and has a plurality of coils 71a wound around a stator core. The rotor 72 includes a plurality of magnets 72a, and the plurality of magnets 72a are arranged in the circumferential direction along an annular track surrounding the stator 71. When the crankshaft 61 rotates, the magnet 72a is displaced relative to the coil 71a, and the ACG starter 54 generates electric power. Conversely, when an electric current flows in the coil 71a, a magnetic field is generated in the coil 71a, causing rotation of the crankshaft 61. The rotor 72 is provided with a vane 72b, and the vane 72b sucks air in the axial direction when rotating and generates an air flow in the centrifugal direction in the housing space.

The power unit 32 includes a dog clutch type transmission 73 combined with the crankshaft 61. The transmission 73 is housed in a transmission chamber 74 that is continuously divided from the crank chamber 53 in the crankcase 38. The transmission 73 includes a main shaft 75 having an axial center parallel to the axial center of the crankshaft 61 and an intermediate shaft (output shaft) 76. The main shaft 75 and the intermediate shaft 76 are rotatably supported by the crankcase 38 via rolling bearings.

A plurality of speed change gears 77 are supported by the main shaft 75 and the intermediate shaft 76. The transmission gear 77 is disposed between the rolling bearings and is accommodated in the transmission chamber 74. The speed change gear 77 includes: a rotary gear 77a supported coaxially with the main shaft 75 or the intermediate shaft 76 so as to be rotatable relative thereto; a fixed gear 77b fixed to the main shaft 75 so as not to be relatively rotatable, and meshing with the corresponding rotary gear 77 a; the shift gears 77c are supported by the main shaft 75 or the intermediate shaft 76 so as to be relatively non-rotatable and axially displaceable, and mesh with the corresponding rotary gears 77 a. The axial displacement of the rotary gear 77a and the fixed gear 77b is restricted. When the shift gear 77c is coupled to the rotary gear 77a by the axial displacement, the relative rotation of the rotary gear 77a and the main shaft 75 or the counter shaft 76 is restricted. When the shift gear 77c meshes with the fixed gear 77b of the other shaft, rotational power is transmitted between the main shaft 75 and the intermediate shaft 76. When the shift gear 77c is linked to the rotary gear 77a that meshes with the fixed gear 77b of the other shaft, rotary power is transmitted between the main shaft 75 and the intermediate shaft 76. In this way, the intermediate shaft 76 outputs the rotational force of the crankshaft 61 at an arbitrary reduction ratio via the transmission 73.

The main shaft 75 is connected to the crankshaft 61 via a primary reduction mechanism 78 that is housed between the crankcase 38 and the clutch cover 59 on the outside of the crankcase 38. The primary speed reduction mechanism 78 includes a power transmission gear 78a and a driven gear 78b supported rotatably relative to the main shaft 75. The power transmission gear 78a is fixed to the other end of the crankshaft 61 projecting outward from the crankcase 38. The driven gear 78b meshes with the power transmission gear 78 a.

The friction clutch 58 housed between the crankcase 38 and the clutch cover 52 is coupled to the main shaft 75. The friction clutch 58 includes a clutch outer 58a and a clutch hub 58 b. The driven gear 78b of the primary speed reduction mechanism 78 is coupled to the clutch outer 58 a. In the friction clutch 58, the clutch outer 58a and the clutch hub 58b are switched between being connected and disconnected according to the operation of the clutch lever.

Sprocket 56 is fixed to intermediate shaft 76. The power transmission device 33 includes a sprocket 56, a driven sprocket fixed to the axle 31 of the rear wheel WR, the sprocket 56, and a winding chain 79 wound around the driven sprocket. The sprocket 56 transmits the rotational force of the intermediate shaft 76 to the rear wheel WR via the winding chain 79.

The ACG cover 55 includes an inner peripheral wall 81a surrounding the rotor 72 of the ACG stator 54 around the rotation axis Rx, and an outer peripheral wall 81b located further outside the rotor 72 of the ACG stator 54 in the axial direction of the rotation axis Rx and surrounding the housing space of the ACG stator 54 around the rotation axis Rx. As shown in fig. 4, the inner peripheral wall 81a and the outer peripheral wall 81b are formed in a cylindrical shape drawn in a circle coaxially with the rotation axis Rx. The outer peripheral wall 81b has a wall 82 continuous over the entire circumference around the rotation axis Rx.

The ACG cover 55 is formed with a mounting boss 84, and the mounting boss 84 is disposed radially outward of the inner peripheral wall 81a, overlaps the outer surface of the crankcase 38, and is fastened to the crankcase 38 by a bolt 83. The ACG cover 55 is coupled to the sprocket cover 57 by a box-shaped expanding body 85 extending rearward from the inner peripheral wall 81 a. A recess 87 is formed in the sprocket cover 57 at a position above and below the sprocket 56, and the recess 87 accommodates the screw 86 for fastening the sprocket cover 57 to the crankcase 38. The floor of the recess 87 overlaps the outer surface of the crankcase 38 and receives the heads of the screws 86 screwed into the crankcase 38.

The outer peripheral wall 81b is provided with a wind guide port 88 for introducing outside air in the radial direction. The air guide opening 88 is disposed below a horizontal plane HP including the rotation axis Rx. A baffle plate 88a is formed on the outer peripheral wall 81b, and the baffle plate 88a is disposed on the air guide opening 88 and extends radially with respect to the rotation axis Rx. The rectifying plates 88a are arranged at equal intervals around the rotation axis Rx.

As shown in fig. 5, the ACG cover 55 includes: an inner member (first body) 55a having a mounting boss 84 (see fig. 4) and fixed to the crankcase 38 to form an inner peripheral wall 81 a; and an outer member (second body) 55b coupled to the inner member 55a and having an outer peripheral wall 81 b. The outer member 55b covers the inner member 55a further outside than the rotor 72 in the axial direction of the rotation axis Rx.

The inner member 55a is formed with a mesh-like partition 89 that partitions the space surrounded by the inner member 55a from the space surrounded by the outer peripheral wall 81 b. As shown in fig. 6, the partition member 89 has a line-shaped body 89a extending in the radial direction from the outer edge of the opening 91 having a circular contour toward the rotation axis Rx, and a circular body 89b drawn concentrically with the circular shape of the opening 91 into a circle and connecting the line-shaped bodies 89 a. The size of the mesh can be set to about 1.5 to 3.0cm square, for example.

As shown in fig. 5, a plurality of projections 92 are formed on the inner surface of the outer member 55b, and the projections 92 project toward the partition 89 above the horizontal plane HP including the rotation axis Rx. The projection 92 is constituted by, for example, a rod having an axis parallel to the rotation axis Rx. The projections 92 are arranged along, for example, an arc drawn concentrically with the rotation axis Rx.

The inner member 55a is formed of a material having higher rigidity than the outer member 55 b. Here, the inner member 55a and the outer member 55b are each molded from a resin material. The inner member 55a is molded from polyamide 66(PA66 resin), for example. The outer member 55b is molded from polypropylene (PP resin), for example.

The inner member 55a has a connection end 93, and the connection end 93 is surrounded by the wall 82 of the outer peripheral wall 81b and radially narrows toward the front end. The connection end 93 has: a first wall 93a that is opposed to the outer peripheral wall 81b and that narrows in the radial direction toward the leading end; a second wall 93b expanding from a front end of the first wall 93a toward the rotation axis Rx; and a third wall 93c that expands from the inner side of the second wall 93b toward the crankcase 38 and forms a space with the first wall 93 a. An opening 91 is defined inside the third wall 93 c. The inner peripheral wall 81a, the first wall 93a, the second wall 93b, and the third wall 93c are continuous with a uniform wall thickness.

As shown in fig. 6, one or more engaging mechanisms 94 that engage with each other are disposed between the connection end 93 and the outer member 55 b. Referring also to fig. 7, the engagement mechanism 94 includes: two grooves 94a formed on the connection end 93 to extend on radial lines; two plates 94b, which are formed on the outer part 55b, extend in radial lines and enter the slots 94a, respectively. Here, the grooves 94a are arranged at intervals of less than 120 degrees around the rotation axis Rx. The grooves 94a may be arranged at intervals other than equal intervals in the circumferential direction. If the grooves 94a are arranged at intervals other than equal intervals, the correspondence relationship between the grooves 94a and the plate pieces 94b is reliably determined, and therefore the outer member 55b can be overlapped with the inner member 55a at a predetermined angular position around the rotation axis Rx without fail. Grooves may be formed in the outer member 55b and a plate may be formed in the inner member 55 a.

As shown in fig. 5, a boss 96 into which a screw 95 penetrating the inner member 55a from the inside of the inner member 55a is screwed is formed on the outer member 55 b. Boss 96 enters recess 93d defined by connection end 93 from the axially outer side, and is received by the bottom plate of recess 93d at the tip. A screw 95 fastens the boss 96 to the bottom plate of the recess 93 d. The screw 95 has an axis center parallel to the rotation axis Rx. As shown in fig. 6, the bosses 96 are arranged at equal intervals of 120 degrees around the rotation axis Rx.

As shown in fig. 5, a gap is formed between the edge (end surface) of the wall 82 and the inner member 55 a. The head of the screw 95 faces a surface 72c of the rotor 72 that is continuous around the rotation axis Rx without interruption outside the cylindrical surface circumscribing the blade 72 b. The vane 72b is formed as a member having a smaller diameter than the surface 72c and fastened to the rotor 72 in a recess inside the surface 72 c.

A partition 97 is formed in the peripheral wall (inner peripheral wall 81a) of the inner member 55a, and the partition 97 vertically extends between the storage space of the ACG starter 54 and the space covered by the sprocket cover 57 to partition the storage space and the sprocket cover. An air outlet 98 is formed at the lower end of the partition 97. As shown in fig. 8, the inner peripheral wall 81a is radially spaced from the outer periphery of the rotor 72 in the rotation direction DR of the rotor 72 as approaching the air outlet 98.

The sprocket cover 57 defines a discharge passage 99 extending from the discharge port 98 by a predetermined length between the sprocket cover and the outer surface of the crankcase 38. The sprocket cover 57 has a partition wall 101, and the partition wall 101 partitions the discharge passage 99 and the space for accommodating the sprocket 56. The air discharge passage 99 is divided between the partition wall 101 and the outer wall 102.

The discharge air passage 99 extends downstream in the rotational direction of the rotor 72 along the tangential direction of an imaginary cylindrical surface surrounding the rotor 72 coaxially with the rotor 72. The discharge passage 99 extends toward the rear of the vehicle body at a position below the sprocket 56. The exhaust passage 99 is inclined so as to descend toward the ground as it goes toward the rear of the vehicle body. The outlet 99a of the exhaust passage 99 faces the coupling 44c fixed to the engine hanger 43 c. In the outlet 99a of the air discharge passage 99, the outer wall of the sprocket cover 57 opposed to the partition wall 101 is folded back upward toward the partition wall 101. The turning back can prevent foreign matter from entering the exhaust passage 99 from below. In the air outlet 98, the outer wall of the ACG cover 55 overlaps the outer wall of the sprocket cover 57 from above. As shown in fig. 1, the outlet 99a of the exhaust passage 99 is disposed rearward of the step plate 34. The outlet 99a of the exhaust passage 99 is located at a position lower than a horizontal plane ZP that circumscribes the rear seat footboard 35 from below.

As shown in fig. 5, the inner member 55a of the ACG cover 55 contacts the crankcase 38 on a mating surface 103 formed on a plane orthogonal to the rotation axis Rx. On the inner member 55a, a water blocking wall 104 is formed, and the water blocking wall 104 protrudes from the outer periphery of the mating face 103 and covers the outer surface of the crankcase 38. As shown in fig. 9, the water blocking wall 104 is disposed forward and upward of the rotation axis Rx. The water blocking wall 104 is continuous from the upper end of the partition wall 97 forward along the mating surface 103, and is interrupted at a position lower than the horizontal plane HP including the rotation axis Rx (see fig. 6).

Next, the operation of the present embodiment will be described. When the air-fuel mixture is exploded in the combustion chamber 49, reciprocating linear motion of the piston 47 is caused in the cylinder 48. The crankshaft 61 rotates in correspondence with the linear reciprocation of the piston 47. As a result, the rotor 72 of the ACG starter 54 is displaced relative to the stator 71. The ACG starter 54 generates electricity.

The blades 72b generate an air flow in a centrifugal direction corresponding to the rotation of the rotor 72. When the airflow is generated, the outside air flows into the housing space of the ACG starter 54 along the second wall 93b of the connection end 93 in the radial direction from the air guide opening 88 of the outer member 55 b. The outside air advances toward the rotor 72 in the axial direction of the rotation axis Rx within the housing space. Since the flow path of the outside air is nonlinear, the flow of foreign matter toward the rotor 72 can be suppressed. The outside air flows into the inner space of the inner member 55a from the opening 91. The outside air cools the ACG starter 54 in the housing space of the ACG starter 54.

The cooling air guided in the centrifugal direction by the rotation of the blades 72b flows out from the air outlet 98 and is guided to the rear of the step plate 34 along the air outlet passage 99. The path of the exhaust air may bypass the feet of the driver. The feet of the driver may not be exposed to the influence of the exhaust.

When the power unit 32 is started, if a current is supplied to the coil 71a of the ACG starter 54, a relative displacement is generated between the coil 71a and the magnet 72 a. Thus, in the ACG starter 54, the rotor 72 rotates. Rotation of rotor 72 causes rotation of crankshaft 61. The blades 72b generate an air flow in a centrifugal direction corresponding to the rotation of the rotor 72. The outside air flows into the inner space of the inner member 55a from the opening 91. The external air cools the ACG starter 54 in the housing space of the ACG starter 54. Warm air is generated due to heat generation of the ACG starter 54. The warm air is guided to the rear of the step 34 along the discharge passage 99. Since the path of the exhaust air avoids the driver's feet, the driver's feet may not be exposed to the warm air from the ACG starter 54.

In the power unit 32 of the present embodiment, the left case cover 45 includes: an ACG cover 55 covering the ACG starter 54 and having

peripheral walls

81a, 81 b; and a sprocket cover 57 disposed behind the ACG cover 55 to cover the sprocket 56, and having a partition wall 101 partitioning the discharge passage 99 from a space for accommodating the sprocket 56. Since the left case cover 45 is formed of the ACG cover 55 and the sprocket cover 57 in this way, the degree of freedom in the shapes of the ACG cover 55 and the sprocket cover 57 is increased during molding. As a result, the degree of freedom of arrangement of the air discharge passage 99 is improved. Further, since the partition wall 101 of the sprocket cover 57 prevents the discharge air from entering toward the sprocket 56, the sprocket 56 can be protected from the accumulation of dust contained in the discharge air.

The discharge passage 99 extends toward the rear of the vehicle body at a position below the sprocket 56. The exhaust air can be discharged downward as much as possible. Thus, the influence of the exhaust air on the occupants is avoided as much as possible.

The discharge air passage 99 extends downstream in the rotation direction DR of the rotor 72 along a tangential direction coaxially surrounding the cylindrical surface of the rotor 72 with the rotor 72. Since the discharge air passage 99 extends in the direction of the air pushed out by the rotational operation of the rotor 72, the discharge air can be efficiently introduced from the housing space of the rotor 72 into the discharge air passage 99.

The outlet 99a of the exhaust passage 99 is located at a position lower than the rear seat step 35 provided in the vehicle body at a position rearward of the step 34. The exhaust air is discharged from a position lower than the feet of the rear seat occupant mounted on the rear seat step plate 35, and therefore the influence of the exhaust air on the feet of the rear seat occupant is suppressed (or avoided).

The exhaust passage 99 is inclined so as to descend toward the ground as it goes toward the rear of the vehicle body. Since the discharge air has directivity in the rear-downward direction, the influence of the discharge air on the driver and the rear seat occupant is suppressed (avoided).

In the present embodiment, the ACG starter 54 generates a driving force that causes rotation of the crankshaft 61 at the time of vehicle startup. In this way, since the alternator also functions as a starter, heat is more likely to be generated than in the case of having only a power generation function. Even in such a case, since the ACG starter 54 is effectively cooled by the action of the ventilation passage 99, heat generation of the ACG starter 54 can be effectively suppressed.

On the rotor 72 of the ACG starter 54, a vane 72b is provided, which vane 72b generates an air flow in a centrifugal direction when the rotor 72 rotates. Since the airflow is generated in accordance with the rotation of the vane 72b, the cooling air can efficiently flow into the housing space of the ACG starter 54. The heat generation of the ACG starter 54 is effectively suppressed.

In the power unit 32 of the present embodiment, the case cover 45 is made of resin. Since the left tank cover 45 is made of resin, it generally has a lower thermal conductivity than a metallic tank cover, and the temperature increase of the tank cover is effectively suppressed. Further, since the left case cover 45 made of resin is lighter in weight than the case cover made of metal, the left case cover 45 made of resin can contribute to weight reduction of the vehicle.

The left tank cover 45 has a water-retaining wall 104, the water-retaining wall 104 being in contact with the crankcase 38 on a mating face 103 formed by a plane orthogonal to the rotation axis Rx, protruding from an outer periphery of the mating face 103 and covering an outer surface of the crankcase 38. When the storage space of the ACG starter 54 is submerged, water that spreads centrifugally from the rotor 72 enters between the crankcase 38 and the left case cover 45 at the mating surface 103. At this time, the water flowing along the mating face 103 is blocked by the water blocking wall 104, and thus the water is prevented from scattering directly outward from the mating face 103 toward the occupant.

At this time, the water blocking wall 104 is disposed forward and upward of the rotation axis Rx. The water is prevented from spreading around the left tank cover 45 in front of and above the rotation axis Rx, but can efficiently leak from the mating surfaces 103 of the crankcase 38 and the left tank cover 45 in the rear of and below the rotation axis Rx. In this way, drainage can be promoted from the storage space of the ACG starter 54.

In the present embodiment, the outlet 99a of the discharge passage 99 is opposed to a coupling 44c fixed to an engine hanger 43c formed on the crankcase 38 and coupled to the vehicle body frame 12. Since the obstacle faces the outlet 99a of the air discharge passage 99, the entry of dust into the air discharge passage 99 is suppressed.

Claims

1. A power unit (32) for a saddle-ride type vehicle, comprising: a crankcase (38) which rotatably supports a crankshaft (61);

an output shaft (76) supported by the crankcase (38) and outputting the rotational force of the crankshaft (61) via a transmission (73);

an alternator (54) having a rotor (72), the rotor (72) being coupled to the crankshaft (61) outside the crankcase (38) and rotating about a rotation axis (Rx) of the crankshaft (61);

a case cover (45) that covers the crankcase (38) from the outside and houses the alternator (54);

the power unit (32) of the saddle-ride type vehicle is characterized in that,

an air discharge passage (99) is formed between the crankcase (38) and the case cover (45), the air discharge passage (99) extends rearward from an air discharge opening (98) defined by a peripheral wall (81a) surrounding the alternator (54) than a step plate (34) attached to the power unit (32) from below and extending in the vehicle width direction,

the discharge passage (99) extends rearward of the vehicle body at a position below a sprocket (56), the sprocket (56) being supported by an output shaft (76) that outputs the rotational force of the crankshaft (61) and transmitting the rotational force of the output shaft (76) to a rear Wheel (WR),

an outlet (99a) of the air discharge passage (99) is disposed behind the step plate (34), and a space for accommodating a sprocket (56) that transmits the rotational force of the output shaft (76) to a rear Wheel (WR) is partitioned by a partition wall (101) of the box cover (45) that partitions the air discharge passage (99).

2. The power unit for a saddle-ride type vehicle according to claim 1,

the output shaft (76) is supported by the crankcase (38) so as to be rotatable around an axis parallel to the rotation axis (Rx) at the rear of the crankshaft (61),

the sprocket (56) is fixed to the output shaft (76) on the outer side of the crankcase (38), covered by the case cover (45) at the rear of the alternator (54), and transmits the rotational force of the output shaft (76) to the rear Wheel (WR) via a winding chain (79),

the box cover (45) has: a generator cover (55) that covers the alternator (54) and has the peripheral wall (81 a); and a sprocket cover (57) which is disposed behind the generator cover (55) and covers the sprocket (56).

3. A power unit (32) for a saddle-ride type vehicle, comprising: a crankcase (38) which rotatably supports a crankshaft (61);

the power unit (32) of the saddle-ride type vehicle is characterized in that,

a space for storing a sprocket (56) for transmitting the rotational force of the output shaft (76) to a rear Wheel (WR) is divided by a partition wall (101) of the box cover (45) for partitioning the air discharge passage (99),

the discharge passage (99) extends downstream in the direction of rotation of the rotor (72) along a tangential direction of a cylindrical surface that surrounds the rotor (72) coaxially with the rotor (72).

4. The power unit for a saddle-ride type vehicle according to claim 3, wherein an outlet (99a) of said exhaust passage (99) is located at a position lower than a rear seat step plate (35) provided on a vehicle body, further rearward than said step plate (34).

5. The power unit for a saddle-ride type vehicle according to claim 4, wherein said air discharge passage (99) is inclined so as to be lowered toward the ground as it goes toward the rear of the vehicle body, and an outlet (99a) of said air discharge passage (99) opens at a position lower than a horizontal plane (ZP) circumscribing the rear seat step plate (35) from below.

6. A power unit (32) for a saddle-ride type vehicle, comprising: a crankcase (38) which rotatably supports a crankshaft (61);

the power unit (32) of the saddle-ride type vehicle is characterized in that,

an air discharge passage (99) is formed between the crankcase (38) and the case cover (45), the air discharge passage (99) extends rearward from an air discharge opening (98) defined by a peripheral wall (81a) surrounding the alternator (54) with respect to a step plate (34) provided on a vehicle body,

the box cover (45) has a partition wall (101) that partitions the discharge passage (99) from a space that houses a sprocket (56) that transmits the rotational force of the output shaft (76) to a rear Wheel (WR),

the tank cover (45) has a water-retaining wall (104), the water-retaining wall (104) being in contact with the crankcase (38) on a mating face (103) formed by a plane orthogonal to the rotation axis (Rx), protruding from an outer periphery of the mating face (103), and covering an outer surface of the crankcase (38).

7. The power unit for a saddle-ride type vehicle according to claim 6, wherein said water guard wall (104) is disposed forward and above said rotation axis (Rx).

8. The power unit of the saddle-ride type vehicle according to any one of claims 3 to 7,

the output shaft (76) is supported by the crankcase (38) so as to be rotatable about an axis parallel to the rotation axis (Rx) at the rear of the crankshaft (61),

9. The power unit of a saddle-ride type vehicle according to any one of claims 1 to 7, wherein the alternator (54) functions as a starter that generates a driving force that causes rotation of the crankshaft (61) at the time of vehicle startup.

10. The power unit for a saddle ride type vehicle according to any one of claims 1 to 7, wherein a blade (72b) is mounted on said rotor (72), said blade (72b) generating an air flow in a centrifugal direction when said rotor (72) rotates.

11. The power unit for a saddle-ride type vehicle according to any one of claims 1 to 7, wherein said case cover (45) is made of resin.

12. The power unit of a saddle ride type vehicle according to any one of claims 1 to 11, wherein an outlet (99a) of said air discharge passage (99) is opposed to a coupling (44c), said coupling (44c) is fixed to an engine hanger (43c), and said engine hanger (43c) is formed in said crankcase (38) and coupled to a vehicle body frame (12) of the vehicle.