CN115217945A

CN115217945A - Gear shifting assembly for internal combustion engine

Info

Publication number: CN115217945A
Application number: CN202210270069.0A
Authority: CN
Inventors: S·K·库马尔; E·西德; K·S·劳
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2021-03-31
Filing date: 2022-03-18
Publication date: 2022-10-21
Also published as: CO2022003604A1

Abstract

The invention relates to a shifting assembly (212) for an internal combustion engine (108). The shift assembly (212) includes a first shift arm (206A) and a second shift arm (206B), a first end of the first shift arm (206A) and a first end of the second shift arm (206B) being connected to the shift shaft (207A) at a first pivot (207). The first transition arm (206A) includes a second end having a first cavity (214) for receiving the retaining pin (205). The second transition arm (206B) includes a second end having a second cavity (210) for receiving a roller (208). An auxiliary arm (203) is rotatably connected to the roller (208) at one end thereof and engages the pawl arm (202) at the other end thereof. This improves the shift feel and provides optimal leverage to provide the force required to shift.

Description

Gear shifting assembly for internal combustion engine

Technical Field

The present subject matter relates to a vehicle. And more particularly, to a saddle type vehicle.

Background

Straddle-type vehicles such as motorcycles generally have a manual transmission system to transmit power generated by an internal combustion engine (1C) to wheels of the vehicle in a controlled manner. Manual transmissions include a system of interlocking gears such that by manually operating a shift lever, a driver can select one of several speed ratios between an input shaft and an output shaft. To achieve smooth and gradual shifting, a clutch is provided to temporarily isolate the engine from the transmission. When the driver manually releases the clutch lever, the plates in the clutch assembly press against each other, so that the transmission is engaged with the engine.

The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Drawings

The invention is described with reference to an exemplary embodiment of a battery module for a saddle-ridden two-wheeled vehicle (commonly known as a motorcycle, in which the rider must straddle). The invention can be implemented in two-wheeled/three-wheeled vehicles. Throughout the drawings, the same numbers are used to reference like features and components. Furthermore, the inventive features of the present invention are set forth in the appended claims.

Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals are used to refer to like parts throughout the various views unless otherwise specified. It should be understood that the following drawings may not be to scale.

The following is a description of certain details and implementations (including a description of the figures) that may depict some or all of the embodiments described below, as well as a discussion of other potential embodiments or implementations of the inventive concepts presented herein. The following provides an overview of embodiments of the invention, followed by a more detailed description with reference to the accompanying drawings.

Fig. 1 illustrates a left side view of an exemplary two-wheeled motor vehicle according to an embodiment, according to one example of the present subject matter.

Fig. 2a shows a left side view of an engine assembly in a two-wheeled motor vehicle according to an example of the present subject matter.

Fig. 2b showsbase:Sub>A cross-sectional view across sectionbase:Sub>A-base:Sub>A' ofbase:Sub>A shifted engine assembly according to an embodiment according to an example of the present subject matter.

Fig. 3 shows a left side view of a shift assembly for an engine assembly according to an embodiment according to an example of the present subject matter, with several parts omitted from the figure.

Fig. 4 shows a diagram depicting the difference in shift lever travel between a conventional shift mechanism and the inventive shift assembly layout according to an example of the present subject matter.

Detailed Description

In the following description, numerous details are set forth to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects.

Conventionally, a two-wheeled vehicle is powered by an internal combustion engine (IC engine) that is generally disposed in the lower half of the vehicle. Engines convert chemical energy into mechanical energy through the combination of an air-fuel mixture within the engine combustion chamber. The IC engine has, among other components, a cylinder block, and includes a cylinder head disposed at a top of the cylinder block and receiving a reciprocating piston from a bottom. When the air-fuel mixture is combusted, the piston transfers energy generated during combustion to the crankshaft through the connecting rod, thereby driving the crankshaft. In this way, the reciprocating motion of the piston is converted into rotational motion of the crankshaft. The crankshaft is accommodated in a crankcase disposed below the cylinder block.

In order to start the vehicle, the power supplied to the crankshaft of the internal combustion engine is transmitted in a controlled manner to the wheels via the transmission system. The transmission system for the engine of a two-wheeled motor vehicle, such as a motorcycle, usually comprises an interlocking gear system, so that by manually operating a gear shift lever, the driver can select one of several speed ratios between the input shaft and the output shaft. To achieve smooth and gradual shifting, a clutch is provided to temporarily isolate the engine and transmission. When the driver manually releases the clutch lever, the discs in the clutch assembly press against each other, and the transmission is thus engaged with the engine.

The rider may decide whether a gear change is required based on engine speed or vehicle instructions provided on the instrument cluster. Typically, motorcycle shifting assemblies are used to manually shift by shifting the position of a shift lever using a foot so that a desired drive gear or neutral position in the gearbox is engaged. In particular, by lifting or pushing down the gear shift lever, a desired drive or neutral position in the gearbox is engaged. The gear shift lever therefore serves as a contact point for manual shifting with the foot. Since the movement is transmitted from the shift lever to the shift shaft, a change of the drive gear position is achieved. The shift shaft is connected to the shift drum by a plurality of shift elements. Typically, a plurality of shifting components (such as pawls, stops, shift arms, and shift drums) are housed within the transmission housing. The shift shaft is connected to the shift arm. One end of the shift arm is connected to the shift shaft and the other end is connected to the pawl. The rotation of the end connected to the shift shaft is limited by a stopper.

Furthermore, in order to ensure good riding ergonomics, it is important to ensure that the shift lever is easily accessible to the rider. Since the gears must be shifted frequently while riding, ideally, the rider should be able to comfortably reach the shift lever with his foot under all riding conditions.

However, it has been observed that the lower lever amplitude required to generate the necessary shifting force can result in incomplete shifting. In addition, due to the low shift lever stroke, the rider tends to have a bad shift feeling. More specifically, due to the lack of positive shift feel by the rider, the rider tends to exert excessive force even after the shift is completed. Excessive force applied by the rider can affect the durability of the parts housed within the transmission housing. More specifically, the pivot area between the shift arm and the pawl arm is prone to failure because it is subjected to additional forces during shifting. In addition, another area prone to failure is between the transition arm and the stop.

In order to solve this problem, an external shifting device is provided outside the transmission housing, which has an additional linkage to facilitate shifting. However, the external gear shifting device only involves an externally retrofittable linkage with little or no modification to the existing gearbox. Such an external design cannot exclude the case of inconsistent shifting.

Accordingly, there is a need to provide an improved shifting assembly that overcomes all of the above-mentioned problems and tradeoffs and overcomes the problems of the prior art.

It is an object of the present invention to provide an improved shifting assembly that provides a better shift feel for the rider.

It is another object of the present invention to provide an improved shifting mechanism that provides optimal leverage to generate the necessary shifting forces, thereby improving the durability of the shifting elements.

To this end, the present invention discloses an improved shifting assembly for an internal combustion engine. The shift assembly includes a shift arm. The switch arm includes a first switch arm and a second switch arm. The first end of the first shift arm and the first end of the second shift arm are connected to the shift shaft at a first pivot. The first switching arm including a second end is configured with a first cavity for receiving a stop pin mounted to a crankcase, and the second switching arm including a second end is configured with a second cavity for receiving a roller. An auxiliary arm is rotatably coupled to the roller at one end thereof and engages a pawl arm at another end thereof, wherein the pawl arm actuates a gear cam assembly of the engine.

According to the above configuration, one of the advantages of the present invention is that the shift arm and the auxiliary arm provide an improved shift feeling due to a higher shift lever stroke. Furthermore, the shifting arm and the auxiliary arm provide an optimal leverage to provide a sufficient shifting force while eliminating stress at the stop pin and the pawl arm, since the shifting arm and the auxiliary arm move in opposite directions to each other.

According to a further embodiment of the invention, the second cavity is elliptical.

According to one embodiment of the invention, the second cavity is configured to receive the roller.

One of the advantages of the present invention, according to the above configuration, is that the second cavity is configured to provide a higher degree of freedom for the roller relative to the shift arm and the auxiliary arm, which in turn allows the pawl arm to move faster.

According to an embodiment of the invention, the auxiliary arm is rotatably connected at the second pivot.

According to an embodiment of the invention, the first and second transition arms are integrally formed as a single unit.

According to the above configuration, one of the advantages of the present invention, the integration of the first and second switching arms enables faster movement of the auxiliary arm. Furthermore, by eliminating mechanical wear, the number of parts is reduced and the durability of the transition arm is improved.

According to another embodiment of the invention, the switching arm is rotated in a first direction, causing the auxiliary arm to rotate in a second direction opposite to the first direction.

According to a further embodiment of the invention, rotation of the auxiliary arm results in linear movement of the pawl arm.

According to one embodiment of the invention, said linear movement of said pawl arm causes a corresponding rotation of a gear cam.

According to another embodiment of the invention, the direction of rotation of the gear cam is opposite to the direction of rotation of the auxiliary arm.

The subject matter is further described with reference to the accompanying drawings. It should be noted that the description and drawings merely illustrate the principles of the present subject matter. Various arrangements may be devised which, although not explicitly described or shown herein, embody the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

The foregoing disclosure is not intended to limit the disclosure to the precise forms or particular fields of use disclosed. It is therefore contemplated that various alternative embodiments and/or modifications of the present disclosure, whether explicitly described or implied herein, are possible in light of the present disclosure. Having thus described the embodiments of the present disclosure, persons of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Accordingly, the disclosure is limited only by the claims.

In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as those skilled in the art will recognize, the various embodiments disclosed herein may be modified or otherwise implemented in various other ways without departing from the spirit and scope of the present disclosure. Accordingly, this description is to be construed as illustrative, and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the present disclosure. It is to be understood that the forms of the disclosure herein illustrated and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, some features of the present disclosure may be employed independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the present disclosure. Expressions such as "comprise", "incorporate", "consist of", "8230", "have", "be", are used to describe and claim the present disclosure are intended to be interpreted in a non-exclusive manner, i.e. to allow items, components or elements not explicitly described to be present as well. Reference to the singular is also to be construed to relate to the plural.

Furthermore, the various embodiments disclosed herein are to be understood as illustrative and explanatory and are not to be construed as limiting the disclosure. All conjunctive references (e.g., attached, fixed, coupled, connected, and the like) are used solely to aid the reader in understanding the present disclosure and do not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Accordingly, conjunctive references, if any, should be interpreted broadly. Furthermore, such joinder references do not necessarily infer that two elements are directly connected to each other.

Furthermore, all numerical terms, such as, but not limited to, "first," "second," "third," "primary," "secondary," "primary," or any other common and/or numerical terms, should also be considered identifiers only to assist the reader in understanding the various elements, embodiments, variations, and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order or preference of any element, embodiment, variation, and/or modification with respect to or with respect to another element, embodiment, variation, and/or modification.

It will also be understood that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Moreover, any signal hatchings in the drawings are to be considered exemplary only, and not limiting, unless otherwise specifically noted.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Referring to fig. 1, an overall schematic structure of a saddle-ride type vehicle two-wheeled vehicle (hereinafter referred to as "vehicle") (100) is described. The vehicle (100) comprises a body frame (101) to support different parts of the vehicle (100). A head pipe (102) is provided at the front end of the main body frame (101). The head pipe (102) rotatably supports a steering shaft (not shown) within a certain range. In an upper portion of the head pipe (102), a handlebar assembly (103) is rotatably integrally connected to a steering shaft (not shown). The handlebar assembly (103) is used to steer the vehicle (100) and is connected to the front wheel (104) by a steering shaft (not shown). The upper part of the front wheel (104) is covered by a front fender (105), and the front fender (105) prevents mud and water from being deflected toward a steering shaft (not shown). Further, a front fork assembly (106) is partially supported on the front fender (105) and connected to the front wheel (104). In a front portion of the main body frame (101), a fuel tank (107) is disposed immediately behind the handlebar (103) and above an internal combustion engine assembly (hereinafter referred to as "engine assembly") (108). The seat (109) is placed behind the fuel tank (107). The seat (109) includes a front rider portion and a rear rider portion. A headlight unit (110) and a turn signal lamp unit (111) are provided at a front portion of a vehicle (100) for the safety of a rider and for the conformity to traffic regulations. The headlight unit (110) and the turn signal lamp unit (111) are housed in a headlight housing assembly (112). A suspension system is provided for comfortable steering of a vehicle (100) on a road. The front fork assembly (106) forming the front suspension system functions as a rigid member as does the main body frame (101). The front fork assembly (106) clamped to the head pipe (102) by the upper bracket (113 a) and the lower bracket (113 b) can move leftward and rightward. Further, a rear suspension system as a hydraulic damping device is connected to the main body frame (101). The rear suspension system comprises at least one rear suspension preferably located on the left side of the vehicle (100). However, in a vehicle (100) having two rear suspensions, the rear suspensions may be disposed on the left and right sides of the vehicle (100), respectively. The engine assembly (108) is mounted to a front lower portion of the main body frame (101) by a first engine mounting bracket (not shown). The engine assembly (108) is equipped with an exhaust system that includes an exhaust pipe (not shown) connected to the engine assembly (108) and a muffler (not shown) connected to the exhaust pipe. A muffler (not shown) extends rearward along the right side of the rear wheel (114). Power from the engine assembly (108) is transmitted through the transmission assembly (118) to the driven sprocket (119) to drive and rotate the rear wheel (114). In particular, the gear change is achieved by operating a shift linkage assembly (115) operatively connected to a shift shaft (207A) (as shown in fig. 2). Thus, power from the engine assembly (108) is transmitted to the rear wheel (114) rotatably supported at the rear end of the swing arm (116). A rear fender 117 for covering an upper side of the rear wheel 114 is mounted to a rear portion of the main body frame 101 to prevent slurry and water splashed by the rotating rear wheel 114 from entering the muffler and engine assembly 108.

Fig. 2a shows a left side view of an engine assembly (108) in a two-wheeled motor vehicle (100) according to an example of the present subject matter. FIG. 2b illustratesbase:Sub>A cross-sectional view of an engine assembly (108) according to an embodiment of the present subject matter, across A-A', with several parts omitted from the figure. For the sake of brevity, fig. 2a and 2b will be discussed together. The engine assembly (108) includes a crankcase (213). The crankcase (213) is configured to support a shift assembly (212). The shift assembly (212) includes a gear cam assembly (201), a pawl arm (202), a secondary arm (203), a second pivot (204), a roller (208), a shift shaft (207A), a first pivot (207), a stop pin (205), a transition arm (206), a spacer and circlip assembly (209), and a spring member (211). One end of the shift shaft (207A) is connected to the shift arm (206), and the opposite end is connected to a shift lever (not shown). The stop pin (205) allows limited rotational movement of the switch arm (206) in a controlled manner. The switch arm (206) includes a first switch arm (206A) and a second switch arm (206B). More specifically, a first end of a first shift arm (206A) and a first end of a second shift arm (206B) are connected to the shift shaft (207A) at a first pivot (207).

According to a preferred embodiment, the first switching arm (206A) is integral with the second switching arm (206B). According to an alternative embodiment, the first transition arm (206A) is detachably attached to the second transition arm (206B) using an attachment means (not shown).

According to a preferred embodiment, the first switching arm (206A) comprises a second end having a first cavity (214) for receiving the stop pin (205). The stopper pin (205) is mounted to the crankcase (213). The second transition arm (206B) includes a second end configured with a second cavity (210) for receiving a roller (208). According to a preferred embodiment, the second cavity (210) is configured to have an elliptical shape. The elliptical shape allows the roller (208) to have a higher degree of freedom with respect to the movement of the switching arm (206) and the auxiliary arm (203). The higher degree of freedom of the roller (208) in turn contributes to a faster movement of the auxiliary arm (203). Furthermore, the auxiliary arm (203) is rotatably mounted at the second pivot (204). According to the embodiment shown, the second pivot (204) comprises a pin (215) mounted to the crankcase (213). More specifically, the secondary arm (203) is rotatably mounted to the pin (215) using a shim and circlip assembly (209). The shim and circlip assembly (209) includes a shim (209A) and a circlip (209B). The shim (209A) avoids wear due to relative movement between the rotating components. A first end of the secondary arm (203) is rotatably coupled to the roller (208) at one end and engages the pawl arm (202) at its other end. The pawl arm (202) is connected to the gear cam assembly (201). The gear cam assembly (201) comprises a gear cam (201A). Further, a spring member (211) connects the pawl arm (202) and the auxiliary arm (203) to enable the auxiliary arm (203) to quickly return toward its initial position after the shift operation is completed.

Fig. 3 shows a left side view of a shift assembly for an engine assembly (108) according to an embodiment according to one example of the present subject matter, wherein several parts are omitted from the figure. During operation, when upshifting or downshifting, a shift lever (not shown) rotates a shift shaft (207A) by the action of a rider's foot. Rotation of the shift shaft (207A) rotates the shift arm (206) in a first direction about the first pivot shaft (207). This causes the auxiliary arm (203) to rotate about the second pivot (204) in a second direction by the roller (208). The second direction is opposite to the first direction. The secondary arm (203) causes linear movement of the pawl arm (202). This results in a corresponding rotation of the gear cam (201A). According to a preferred embodiment, the direction of rotation of the gear cam (201A) is opposite to the direction of rotation of the auxiliary arm (203).

Fig. 4 shows a diagram depicting the difference in shift lever travel between a conventional shift mechanism and the inventive shift assembly layout according to an example of the present subject matter. Preferably, the vertical axis represents the degree of rotation of the gear cam in upshifting and downshifting, and the horizontal axis represents the degree of rotation of the shift lever in upshifting and downshifting. As shown, line a represents a conventional shift assembly and line B represents the shift assembly proposed herein with higher shift lever travel. Referring to line C-C 'for upshifts and line D-D' for downshifts, it is apparent from the graph that the shift stroke is higher with the shift assembly proposed herein than with a conventional shift assembly for the same gear cam rotation. This provides the rider with a better shift feel and provides optimized leverage to generate the necessary shifting force. This further prevents incomplete gear selection.

While the invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. A shift assembly (212) for an internal combustion engine (108), the shift assembly (212) comprising:

a transition arm (206), the transition arm (206) comprising:

a first transition arm (206A), and

a second switching arm (206B),

wherein a first end of the first shift arm (206A) and a first end of the second shift arm (206B) are connected to a shift shaft (207A) at a first pivot (207),

wherein the first transition arm (206A) comprising a second end is configured with a first cavity (214) for receiving a stop pin (205), the stop pin (205) being mounted to a crankcase (213), and

wherein the second switching arm (206B) comprising a second end is configured with a second cavity (210) for accommodating a roller (208),

a secondary arm (203), the secondary arm (203) rotatably coupled to the roller (208) at one end thereof and engaging a pawl arm (202) at another end thereof, wherein the pawl arm (202) actuates a gear cam assembly (201) of the engine (108).

2. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the second cavity (210) is oval-shaped.

3. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the second cavity (210) is configured to receive the roller (208).

4. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the auxiliary arm (203) is rotatably connected at a second pivot (204).

5. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the first shift arm (206A) and the second shift arm (206B) are integrally formed as a single unit with one another.

6. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the shift arm (206) rotates in a first direction causing the auxiliary arm (203) to rotate in a second direction opposite the first direction.

7. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein rotation of the auxiliary arm (203) results in linear movement of the pawl arm (202).

8. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the linear movement of the pawl arm (202) results in a corresponding rotation of the gear cam assembly (201).

9. The shift assembly (212) for an internal combustion engine (108) of claim 1, wherein the direction of rotation of the gear cam assembly (201) is opposite a direction of rotation of the assist arm (203).

10. A two-wheeled straddle-type vehicle comprising a shift assembly (212) according to any of the preceding claims.