JP6915413B2 - Vehicle transmission - Google Patents

Description

The present invention relates to a vehicle transmission.

Motorcycles are equipped with a transmission that transmits the driving force of the crankshaft to the rear wheels via a clutch mechanism. The transmission mounted on a motorcycle is provided with a plurality of transmission gears on the counter shaft and the drive shaft, respectively, and shifts are performed by changing the combination of the meshing transmission gears.

The transmission is provided with a gear shift mechanism as a mechanism for changing the combination of meshing transmission gears (see, for example, Patent Document 1). Specifically, in Patent Document 1, a shift change pedal operated by an occupant's foot is connected to one end of a shift shaft via a link. A shift arm is provided at the other end of the shift shaft, and the shift arm is connected to the shift cam. A plurality of shift forks are engaged with the shift cam, and the shift fork is configured to be slidable in the axial direction according to the rotation of the shift cam.

When the shift change pedal is rotated by the occupant, the shift shaft rotates via the link, and the shift arm and the shift cam also rotate with the rotation of the shift shaft. As a result, the shift fork is slid, and various transmission gears engaged with the shift fork are also slid in the axial direction. As a result, the combination of transmission gears is changed.

Japanese Unexamined Patent Publication No. 2014-888942

By the way, in the gear shift mechanism described in Patent Document 1, the shift shaft is cantilevered and supported, and the tip (one end) of the shift shaft projects outward in the vehicle width direction of the crankcase. Therefore, depending on the operating force of the shift change pedal, the shift shaft may bend or twist, which may affect the shift feeling.

The present invention has been made in view of the above points, and one of the objects of the present invention is to provide a speed change device for a vehicle capable of preventing bending and twisting of a shift shaft and improving a shift feeling.

The vehicle transmission of one aspect of the present invention is a vehicle transmission including a shift shaft that rotates in response to an operation of a shift pedal, and has a first support portion that supports at least one end of the shift shaft. comprising an engine casing, and a engine cover for covering the side of the engine case, the engine cover, have a second support portion for supporting the other end of the shift shaft, the shift operation of the shift pedal Further provided with a shift link that transmits to the shaft, the shift link is provided at the end of the shift shaft on the same side as the second support, and the shift link is more of an engine than the second support. It is positioned inside and said Rukoto.

According to the present invention, it is possible to prevent bending and twisting of the shift shaft and improve the shift feeling.

It is a left side view which shows the schematic structure of the motorcycle to which the transmission device which concerns on this embodiment are applied. It is a perspective view of the engine which concerns on this embodiment. It is a left side view of the engine shown in FIG. It is sectional drawing which cut along the AA line of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, an example in which the transmission according to the present invention is applied to a sports type motorcycle will be described, but the application target is not limited to this and can be changed. For example, the transmission according to the present invention may be applied to other types of motorcycles, buggy type motorcycles, motorcycles and the like. Further, regarding the direction, the front of the vehicle is indicated by an arrow FR, the rear of the vehicle is indicated by an arrow RE, the left side of the vehicle is indicated by an arrow L, and the right side of the vehicle is indicated by an arrow R. Further, in each of the following figures, some configurations are omitted for convenience of explanation.

A schematic configuration of the motorcycle according to the present embodiment will be described with reference to FIG. FIG. 1 is a left side view showing a schematic configuration of a motorcycle to which the transmission according to the present embodiment is applied.

As shown in FIG. 1, the motorcycle 1 is configured by suspending the engine 2 on a vehicle body frame 10 on which each part such as a power unit and an electrical system is mounted. The engine 2 is composed of, for example, a parallel two-cylinder water-cooled engine. The engine 2 is configured by attaching a cylinder block 21, a cylinder head 22, and a cylinder head cover 23 (see FIGS. 2 and 3 for details) on an upper portion of a crankcase 20 in which a crankshaft (not shown) or the like is housed. .. An oil pan 24 (see FIGS. 2 and 3) is provided at the lower part of the crankcase 20. In the present embodiment, the crankcase 20 and the cylinder block 21 are collectively referred to as an engine case. The detailed configuration around the engine will be described later.

The vehicle body frame 10 is, for example, a diamond frame formed by welding a metal pipe, and is configured so that rigidity of the entire vehicle body can be obtained by suspending the engine 2 as described above. The vehicle body frame 10 extends rearwardly and downwardly from the head pipe 10a. A bracket portion 10b that supports the front side (cylinder head 22) of the engine 2 is formed in the front half portion of the vehicle body frame 10. A pivot portion 10c, which is a swing axis of the swing arm 18, is formed at the rear portion of the vehicle body frame 10.

A seat rail 10d extending rearward is provided at a substantially central portion of the vehicle body frame 10 in the front-rear direction. Further, the vehicle body frame 10 above the pivot portion 10c is provided with a back stay 10e extending rearward and upward. A fuel tank 11 is provided above the vehicle body frame 10, and a rider seat 12 and a pillion seat 13 are provided behind the fuel tank 11 along the seat rail 10d. The periphery of the head pipe 10a is covered by the front cowl 14, and the front lower portion of the engine 2 is covered by the under cowl 15.

A pair of left and right front forks 16 are steerably supported by the head pipe 10a via a steering shaft (not shown). The front wheels 17 are rotatably supported at the lower part of the front fork 16, and the upper part of the front wheels 17 is covered with the front fender 17a.

The swing arm 18 is swingably supported by the pivot portion 10c and extends rearward. A rear wheel 19 is rotatably supported at the rear end of the swing arm 18.

Next, the engine according to the present embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of the engine according to the present embodiment. FIG. 3 is a left side view of the engine shown in FIG.

As shown in FIGS. 2 and 3, the crankcase 20 that forms a part of the engine case is vertically divided and has an upper upper case 20a and a lower lower case 20b. By combining the upper case 20a and the lower case 20b, a space for accommodating various shafts is formed in the crankcase 20. The upper front side of the upper case 20a is open, and a cylinder block 21 is attached to the upper case 20a so as to close the opening. The lower case 20b is opened downward, and an oil pan 24 is attached to the lower case 20b so as to close the opening. In particular, the engine 2 is arranged so that the axis of the cylinder block 21 is tilted forward with respect to the vertical direction.

Further, an oil cooler (not shown) for cooling the oil in the engine 2 and an oil filter 26 for filtering dirty oil are attached to the front portion of the lower case 20b. The oil cooler and the oil filter 26 are arranged side by side, and the oil filter 26 is provided on the left side with respect to the oil cooler.

Openings are formed on both the left and right sides of the crankcase 20. A magneto cover 28 that covers a magneto (not shown) is attached to the opening on the left side as an engine cover. On the other hand, a clutch cover 29 that covers a clutch (not shown) is attached to the opening on the right side as an engine cover. An oil inspection window 20c is formed on the side surface of the crankcase 20 (lower case 20b) below the magneto cover 28.

A transmission (not shown) is housed in the rear space inside the crankcase 20. The transmission is composed of a so-called constantly meshing type transmission in which a plurality of transmission gears provided on the counter shaft (not shown) and the drive shaft 25 are always meshed with each other. The transmission according to the present embodiment performs shifting by switching the combination (meshing) of each transmission gear by the shift mechanism 3 described later. That is, the transmission in the present invention is a concept including a transmission and a shift mechanism 3.

The left end of the drive shaft 25 protrudes from the crankcase 20, and a sprocket (not shown) is provided at the protruding portion. A chain (not shown) is wound around the sprocket, and the rotation of the drive shaft can be transmitted to the rear wheels 19 (see FIG. 1) via the chain. Further, a sprocket cover 27 for covering the sprocket is provided on the left end side of the drive shaft 25, that is, on the left side surface of the crankcase 20 behind the magneto cover 28.

A shift pedal 30 forming a part of the shift mechanism 3 is provided on the left side surface of the crankcase 20 (lower case 20b) below the sprocket cover 27. The shift pedal 30 is composed of a lever portion 32 extending rearward from the shaft portion 31 serving as a rotation axis, and a pedal portion 33 protruding to the left from the rear end of the lever portion 32. The shaft portion 31 is formed so as to project to the left from the side surface of the lower case 20b, and the left-right direction is the axial direction. The shift pedal 30 is attached to the lower case 20b so that it can swing up and down around the shaft portion 31.

A shift rod 34 is attached to the shift pedal 30 as a part of a link mechanism that transmits the operation of the shift pedal 30 to the shift shaft 36. The shift rod 34 extends in a substantially vertical direction, and its lower end is connected to the shift pedal 30. Specifically, the lower end of the shift rod 34 is on the base end side of the shift pedal 30, and is swingably supported on the side surface of the lever portion 32 behind the shaft portion 31 (pedal portion 33 side).

The shift rod 34 extends to the vicinity of the upper end of the upper case 20a, and one end of the shift link 35 is swingably connected to the tip of the shift rod 34. In the present embodiment, the shift rod 34 and the shift link 35 are collectively referred to as a link mechanism. The other end of the shift link 35 is fixed to the shift shaft 36. As a result, the shift link 35 and the shift shaft 36 are integrally rotatable.

The shift shaft 36 extends in the vehicle width direction (left-right direction), and one end side (right side) penetrates into the upper case 20a and is supported, while the other end side (left side) is a part of the magneto cover 28 (left side). It is supported by the left end side support portion 28c) described later. The shift shaft 36 penetrating into the upper case 20a is provided with a mechanism (for example, a shift drum or a shift fork) for sliding the predetermined transmission gear in the axial direction (left-right direction).

In the transmission configured in this way, when the shift pedal 30 is operated by the occupant, the shift shaft 36 is rotated via the link mechanism (shift rod 34 and shift link 35). The rotational movement of the shift shaft 36 is transmitted to the mechanism inside the crankcase 20, and some of the transmission gears are slid in the axial direction. As a result, the combination of transmission gears is switched so as to have a predetermined gear ratio.

By the way, in a transmission of a motorcycle, particularly a shift mechanism, there is a shift shaft in which a shift shaft for transmitting the operation of a shift pedal is cantilevered and supported by an engine case and protrudes from a side surface of the engine case. In this case, the shift shaft is bent or twisted by receiving an axial force or the like when operating the shift pedal. In the conventional shift mechanism, such bending and twisting of the shift shaft have not been taken into consideration.

In particular, when the width dimension of the engine becomes large like a multi-cylinder engine, it is necessary to lengthen the shift shaft by that amount, so that the influence of bending and twisting as described above may be further increased. As a result, it is expected that the shift feeling will deteriorate.

For example, it is conceivable to shorten the length of the shift shaft as much as possible by extending the support portion on the engine case side that supports one end of the shift shaft in the axial direction. However, as a result of the complexity of the engine case mold, not only the increase in gravity of the engine case but also the castability of the engine case may be affected.

Therefore, the inventor of the present invention has come up with the idea of supporting the shift shaft with both hands, paying attention to the peripheral configuration on the other end side of the shift shaft that rotates in response to the operation of the shift pedal. Specifically, in the present embodiment, at least one end (right end) of the shift shaft 36 extending in the vehicle width direction is supported by the engine case (crankcase 20), and the other end (left end) of the shift shaft 36 is supported by the engine cover (magneto cover). The configuration is supported by 28).

According to this configuration, the shift shaft 36 can be supported by both sides from the end portion of the shift shaft 36 on the crankcase 20 side to the end portion on the magneto cover 28 side. As a result, the shift shaft 36 can be supported more stably than when the shift shaft 36 is cantilevered, and the bending and twisting of the shift shaft 36 that occurs when the shift pedal is operated can be suppressed. As a result, the operating force of the shift pedal can be directly transmitted from the shift shaft 36 to the mechanism inside the crankcase 20, and the shift feeling can be improved.

In particular, even if the left-right width of the engine 2 becomes large and the shift shaft 36 becomes long as in the parallel two-cylinder engine of the present application, the above effect can be obtained by supporting the shift shaft 36 with both sides. Is.

Further, since the double-sided support structure of the shift shaft 36 can be realized by a simple shape change without significantly changing the shape of the crankcase 20, the castability and the weight of the entire engine are not significantly affected. .. Therefore, it is possible to balance the weight reduction of the engine and the rigidity of the shift shaft.

In particular, the magneto cover 28, which has a relatively simple shape with respect to the crankcase 20 having a complicated shape, is configured to support the other end of the shift shaft 36, so that the load due to the design change of the magneto cover 28 can be applied. Can be reduced.

Next, the bearing structure of the shift shaft according to the present embodiment will be described in detail with reference to FIGS. 2 to 4. FIG. 4 is a cross-sectional view taken along the line AA of FIG.

As described above, in the present embodiment, the magneto cover 28 is configured to support the left end of the shift shaft 36. Specifically, as shown in FIGS. 2 and 3, the magneto cover 28 includes a first cover portion 28a that mainly covers a circular magneto, a second cover portion 28b that covers a starter idle gear (not shown), and a shift shaft. It is composed of a left end side support portion 28c (second support portion) that supports the left end of 36.

The first cover portion 28a is formed in a substantially circular shape in a side view, and an oil supply port 28d is provided near the upper end of the left side surface. The second cover portion 28b is formed so as to project from the outer peripheral portion (arc portion) on the rear upper side of the first cover portion 28a toward the rear upper side, and has a substantially triangular shape in a side view. The left end side support portion 28c is formed so as to project rearward from the vicinity of the rear end portion of the second cover portion 28b, and has a tapered side view substantially triangular shape.

As shown in FIG. 4, the upper case 20a includes a right end side support portion 20d (first support portion) that supports the right end of the shift shaft 36 and a seal portion 20e provided at a substantially central portion in the axial direction of the shift shaft 36. And are formed. The right end side support portion 20d is formed in the vicinity of the upper end on the right side inside the upper case 20a. The seal portion 20e is provided between the left end side support portion 28c and the right end side support portion 20d, and is formed at substantially the center of the upper case 20a in the left-right direction at the same height as the right end side support portion 20d.

A bearing 40 is press-fitted into the right end side support portion 20d from the right side, and the right end of the shift shaft 36 is inserted into the bearing 40. That is, the right end of the shift shaft 36 is supported by the right end side support portion 20d via the bearing 40. Further, a washer 41 and a circlip 42 having a diameter larger than that of the bearing 40 are attached to the right side surface of the bearing 40. The circlip 42 is engaged with an annular groove formed on the outer peripheral surface of the shift shaft 36. As a result, the axial movement of the bearing 40 is restricted.

An oil seal 43 is press-fitted into the seal portion 20e from the left side, and a shift shaft 36 is inserted through the oil seal 43. Further, a washer 44 and a circlip 45 having a diameter larger than that of the oil seal 43 are attached to the left side surface of the oil seal 43. The circlip 45 is engaged with the annular groove formed on the outer peripheral surface of the shift shaft 36 in the same manner as described above. As a result, the axial movement of the oil seal 43 is restricted.

A bearing 46 is press-fitted into the left end side support portion 28c from the right side, and the left end of the shift shaft 36 is press-fitted into the bearing 46. That is, the left end of the shift shaft 36 is supported by the left end side support portion 28c via the bearing 46. Further, although not shown, a washer and a circlip are attached to the right side surface of the bearing 46 like other support portions, and the axial movement of the bearing 46 is restricted.

By supporting the shift shaft 36 at two locations at both ends of the shift shaft 36 in this way, the operating force of the shift pedal 30 can be distributed and handled by the two support portions, and the shift shaft 36 can be bent or twisted. It is possible to suppress. Further, although the number of support points of the shift shaft 36 has increased as compared with the conventional case, the total number of the bearings 40, 46 and the oil seal 43 can increase the rigidity of the shift shaft without changing from the conventional one.

Further, the shift link 35 is provided on the left end side of the shift shaft 36 (the end on the same side as the left end side support portion 28c) and inside (right side) of the engine 2 with respect to the left end side support portion 28c. As a result, the shift link 35 can be brought close to the left end side support portion 28c. Since the axial force generated by the operation of the shift pedal 30 is transmitted to the shift shaft 36 via the shift link 35, the shift shaft 36 in the vicinity of the shift link 35 is supported by the left end side support portion 28c, so that the shift link It is possible to more effectively suppress the bending of the shift shaft 36 in the vicinity of. In this case, since it is sufficient to mainly consider the torsional rigidity of the shift shaft 36, it is possible to reduce the weight of the shift shaft 36 (for example, a hollow structure or a smaller diameter).

Further, the left side surface of the bearing 46 is covered by the left end side support portion 28c, while the right side surface of the bearing 46 is covered by the shift link 35 by arranging the shift link 35 in close proximity. This makes it possible to protect the bearing 46 with the existing configuration without adding a separate member for dust protection.

In the above embodiment, the parallel two-cylinder engine 2 has been described as an example, but the present invention is not limited to this configuration. For example, the engine 2 may be composed of a single-cylinder engine or an engine having three or more cylinders, and the arrangement of the cylinders is not limited to parallel and can be changed as appropriate.

Further, in the above embodiment, the vehicle body frame 10 is composed of a diamond frame, but the present invention is not limited to this configuration. The body frame 10 may be, for example, a twin spar type frame.

Further, in the above embodiment, the shift pedal 30, the shift rod 34, and the shift link 35 are arranged on the left side of the crankcase 20, but the configuration is not limited to this. The shift pedal 30, shift rod 34, and shift link 35 may be arranged on the right side of the crankcase 20.

Further, in the above embodiment, the shift shaft 36 is configured to project to the left from the crankcase 20, but the configuration is not limited to this configuration. The shift shaft 36 may project to the right from the crankcase 20.

Further, in the above embodiment, the magneto cover 28 has been described as an example of the engine cover, but the present invention is not limited to this configuration. As the engine cover, a clutch cover 29 or a sprocket cover 27 may be used.

Further, in the above embodiment, the shift shaft 36 is supported at two places, but the present invention is not limited to this configuration. The shift shaft 36 may be supported at three or more locations.

Further, in the above embodiment, the shift link 35 is arranged in the vicinity of the left end side support portion 28c, but the present invention is not limited to this configuration. The shift link 35 may be arranged at any position in the axial direction of the shift shaft 36.

Moreover, although the present embodiment and the modified example have been described, as another embodiment of the present invention, the above-described embodiment and the modified example may be combined in whole or in part.

Further, the embodiment of the present invention is not limited to the above-described embodiment, and may be variously modified, replaced, or modified without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in another way by the advancement of technology or another technology derived from it, it may be carried out by using that method. Therefore, the scope of claims covers all embodiments that may be included within the scope of the technical idea of the present invention.

As described above, the present invention has the effect of preventing bending and twisting of the shift shaft and improving the shift feeling, and is particularly useful for a transmission applicable to motorcycles. ..

1 Motorcycle 2 Engine 20 Crankcase (engine case)
20a Upper case (engine case)
20b Lower case (engine case)
20d Right end side support part (first support part)
28 Magneto cover (engine cover)
28c Left end support (second support)
30 Shift Pedal 35 Shift Link 36 Shift Shaft 40, 46 Bearing 43 Oil Seal

Claims (4)

A vehicle transmission equipped with a shift shaft that rotates in response to the operation of a shift pedal.
An engine case having a first support portion that supports at least one end of the shift shaft, and an engine case.
An engine cover that covers the side of the engine case is provided.
The engine cover is to have a second support portion for supporting the other end of the shift shaft,
A shift link that transmits the operation of the shift pedal to the shift shaft is further provided.
The shift link is provided at the end of the shift shaft on the same side as the second support.
The shift link, the transmission of a vehicle, characterized in Rukoto arranged inside the engine than the second support portion. The first support portion and the second support portion each support the shift shaft via bearings.
The vehicle transmission according to claim 1, wherein the engine case is provided with an oil seal between the first support portion and the second support portion. The vehicle transmission according to claim 2 , wherein the bearing provided in the second support portion is covered with the engine cover. The vehicle transmission according to any one of claims 1 to 3 , wherein the engine cover is composed of a magneto cover for covering a magneto provided in the engine case.

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