JP2019018586A - Vehicular structure for motorcycle - Google Patents

Abstract

To shorten a wheel base and to elongate a swing arm.SOLUTION: A motorcycle (1) includes: a crank shaft (35) that extends in the horizontal direction; a main shaft (36) which extends in the same direction as that of the crank shaft and which transmits the rotation of the crank shaft; a drive shaft (37) which extends in the same direction as that of the crank shaft and which transmits the rotation of the main shaft; and a pivot shaft (38) which extends in the same direction as that of the crank shaft, and which supports a swing arm so as to be swingable. The main shaft is placed at the front lower side of the crank shaft, and the drive shaft is placed at the lower side of the crank shaft and at the rear side of the main shaft. The pivot shaft is placed inside a triangle that interconnects respective centers of the crank shaft, the main shaft, and the drive shaft in a side view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle structure of a motorcycle.

  In recent motorcycles, it has become popular to reduce the wheelbase of a vehicle to obtain a light ride. Therefore, conventionally, a motorcycle vehicle structure has been proposed that improves the maneuverability by shortening the distance between the front wheels and the rear wheels (see, for example, Patent Document 1).

  Patent Document 1 discloses an L-type twin engine. By contriving various shaft arrangements in the engine, mass concentration, engine compactness, and shortening of the wheel base are realized. Specifically, the main shaft is disposed in front of and below the crankshaft, and the drive shaft is disposed in front of the crankshaft and behind the main shaft.

JP-A-7-304484

  By the way, in motorcycles, in order to improve steering stability, it is desired to lengthen the swing arm (rear arm) so as to reduce the geometric change due to the rear suspension stroke.

  However, in Patent Document 1, it is difficult to lengthen the swing arm if priority is given to shortening the distance between the front wheels and the rear wheels. That is, there is a trade-off relationship between the distance between the axes of the front and rear wheels and the length of the swing arm.

  The present invention has been made in view of this point, and an object of the present invention is to provide a vehicle structure of a motorcycle capable of lengthening a swing arm while shortening a wheel base.

  A motorcycle structure of a motorcycle according to one aspect of the present invention includes a crankshaft extending in a left-right direction of the motorcycle, a main shaft extending in the same direction as the crankshaft and transmitting rotation of the crankshaft, and the same direction as the crankshaft. A drive shaft that transmits the rotation of the main shaft, and a pivot shaft that extends in the same direction as the crank shaft and supports a swing arm so as to be swingable. The drive shaft is disposed below the crank shaft and behind the main shaft, and the pivot shaft connects the centers of the crank shaft, the main shaft, and the drive shaft in a side view. It is arranged inside a triangle.

  According to the present invention, the swing arm can be lengthened while shortening the wheel base.

1 is a left side view showing a schematic configuration of a motorcycle according to the present embodiment. It is a schematic diagram which shows the variation of an axial arrangement | positioning of an engine. It is a left side view showing a schematic configuration of a motorcycle according to a comparative example.

  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 vehicle structure of the motorcycle 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 vehicle structure of a motorcycle according to the present invention may be applied to other types of motorcycles, buggy-type motorcycles, motorcycles, and the like. Regarding the direction, the front of the vehicle is indicated by an arrow FR, and the rear of the vehicle is indicated by an arrow RE. In the following drawings, a part of the configuration is omitted for convenience of explanation.

  A schematic configuration of a motorcycle to which the vehicle structure of the motorcycle according to the present embodiment is applied will be described with reference to FIGS. 1 and 3. FIG. 1 is a left side view showing a schematic configuration of the motorcycle according to the present embodiment. FIG. 3 is a left side view showing a schematic configuration of the motorcycle according to the comparative example. Since FIG. 1 and FIG. 3 differ only in the arrangement of engine components and motorcycle components, the components having the same names are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIGS. 1 and 3, in the motorcycle 1, a power unit 3 is mounted on a body frame 2. The power unit 3 is configured, for example, by combining a water-cooled single cylinder engine or a parallel multi-cylinder engine with a transmission (not shown).

  The power unit 3 is configured by attaching a cylinder block 31, a cylinder head 32, and a cylinder head cover 33 to an upper part of a crankcase 30 in which a crankshaft 35 having an axial direction in the left-right direction is accommodated. The axis of the cylinder block 31 is inclined forward with respect to the vertical direction. An oil pan 34 is provided below the crankcase 30. In the present specification, the crankcase and the cylinder block are collectively referred to as an engine case.

  In the crankcase 30, in addition to the crankshaft 35, various shafts that transmit the rotation of the crankshaft 35 to the rear wheel 53 are disposed (accommodated). Specifically, a main shaft 36 (which may be called a counter shaft) that transmits the rotation of the crankshaft 35 and a drive shaft 37 that transmits the rotation of the main shaft 36 are disposed in the crankcase 30. . These shaft arrangements will be described later.

  The vehicle body frame 2 is, for example, an aluminum twin spar frame or a diamond frame, and is configured to obtain rigidity as a whole vehicle body by suspending the power unit 3 as described above. The body frame 2 as a whole has a shape extending from the front to the rear and curved downward on the rear end side.

  Specifically, the vehicle body frame 2 includes a pair of left and right main frames 21 extending rearward and downward from the head pipe 20 and a body frame 22 extending downward from the rear end of the main frame 21. The main frame 21 is provided with an engine suspension (not shown) extending downward, and the engine suspension supports the front side of the power unit 3 (for example, the cylinder head 32).

  The body frame 22 supports the rear part of the power unit 3 at the upper and lower ends. A pivot shaft 38 that supports the swing arm 25 in a swingable manner is disposed at a substantially central portion of the body frame 22 in the vertical direction. At the upper end of the body frame 22, a seat rail 23 and a back stay 24 extending rearward and upward are provided.

  In FIG. 3, a fuel tank 40 is disposed above the main frame 21. A seat 41 is disposed along the seat rail 23 behind the fuel tank 40. Below the seat 41, an electrical component 42 such as a battery is disposed inside the upper ends of the pair of body frames 22.

  A pair of left and right front forks 50 are supported on the head pipe 20 via a steering shaft (not shown) so as to be steerable. A front wheel 51 is rotatably supported at a lower portion of the front fork 50, and an upper portion of the front wheel 51 is covered with a front fender 52.

  The swing arm 25 extends rearward from the pivot shaft 38. A rear suspension (not shown) is provided between the swing arm 25 and the body frame 22. A rear wheel 53 is rotatably supported at the rear end of the swing arm 25.

  An exhaust pipe 6 and a muffler 7 are connected to the exhaust port of the cylinder head 32 as an exhaust system. The exhaust port is provided toward the front side of the power unit 3. The exhaust pipe 6 extends downward from the exhaust port, bends backward at the front lower side of the power unit 3, and extends to the rear of the power unit 3. A muffler 7 is attached to the rear end of the exhaust pipe 6.

  By the way, in recent motorcycles, it has become popular to reduce the wheel base of the vehicle (the distance between the front and rear wheels) to obtain a light ride. On the other hand, in motorcycles, in order to improve steering stability, it is desired to lengthen the swing arm (rear arm) so as to reduce the geometric change due to the rear suspension stroke.

  When the change in geometry is large, restrictions on the positional relationship between the swing range of the swing arm and the peripheral parts become large, which can be a factor in increasing the design man-hours. Also, lengthening the swing arm is contrary to shortening the wheelbase. That is, since the wheel base and the length of the swing arm are in a trade-off relationship, it is difficult to lengthen the swing arm while shortening the wheel base.

  For example, in the power unit 3 according to the comparative example shown in FIG. 3, the axis C of the cylinder block 31 is inclined forward with respect to the vertical direction, and the crankshaft 35 is disposed on the extended line of the axis C below the cylinder block 31. Has been. A main shaft 36 is disposed behind the crankshaft 35, and a drive shaft 37 is disposed behind the main shaft 36. Further, a pivot shaft 38 is disposed behind the drive shaft 37, and these four axes are aligned in a straight line in a substantially horizontal direction. For this reason, the entire power unit 3 is enlarged in the front-rear direction.

  In the comparative example, in order to shorten the wheel base L1 (distance L1 between the front wheel 51 and the rear wheel 53), (1) the length of the swing arm 25 (distance L2 between the pivot shaft 38 and the rear wheel 53). ) Is shortened, or (2) the front wheels 51 are brought closer to the power unit 3 side, that is, the front wheels 51 are offset backward. If the swing arm 25 is shortened, the geometric change due to the rear suspension stroke becomes large, which is not preferable. Further, if the front wheel 51 is brought closer to the power unit 3 side, the front wheel 51 may interfere with the power unit 3 due to the clearance relationship between the power unit 3 and the front wheel 51. Thus, in the comparative example, it is difficult to achieve both shortening of the wheel base L1 and extension of the swing arm 25.

  Therefore, the present inventor has paid attention to various shaft arrangements of the power unit 3 and has conceived of making the swing arm longer while shortening the wheel base. Specifically, in the present embodiment, as shown in FIG. 1, the main shaft 36 is disposed on the front lower side of the crankshaft 35, and the drive shaft 37 is below the crankshaft 35 (front lower side) and behind the main shaft 36. (Rear and lower). Further, the pivot shaft 38 is disposed in front of the crankshaft 35 (lower front and upper rear of the drive shaft 37). More specifically, the pivot shaft 38 is arranged inside a triangle connecting the centers of the crank shaft 35, the main shaft 36, and the drive shaft 37.

  According to this configuration, the drive shaft 37 is arranged in front of the crankshaft 35, so that the pivot shaft 38 can be arranged in front of the power unit 3. As a result, the length of the swing arm 25 (distance L4 between the pivot shaft 38 and the rear wheel 53) can be made longer than that of the comparative example.

  In the present embodiment, the cylinder head cover 33, the cylinder head 32, and the cylinder block 31 are sandwiched between the pair of left and right main frames 21, and the axis C (axial direction) of the cylinder block 31 is the pair of left and right mains. The frame 21 is arranged so as to be parallel to the extending direction. The crankshaft 35 is disposed on the extension line of the axis C behind the cylinder block 31.

  Since the left and right sides of the power unit 3 are surrounded by the pair of main frames 21 in this way, the rigidity of the power unit 3 can be utilized to improve the vehicle body rigidity. In addition, since the axial direction of the cylinder block 31 is aligned with the extending direction of the main frame 21, the crankshaft 35 can be disposed above the vehicle, and the main shaft 36 and the drive shaft 37 are disposed below the crankshaft 35. It became possible to do. Thereby, the front-rear width of the power unit 3 can be reduced, and a space S can be secured between the front wheel 51 and the power unit 3 in the front lower part of the cylinder head 32, that is, in front of the crankcase 30. Thereby, the front wheel 51 can be shifted and arranged on the power unit 3 side (rear side of the vehicle) without interfering with the power unit 3. As a result, the wheel base L3 (distance L3 between the front wheel 51 and the rear wheel 53) can be made smaller than that of the comparative example.

  Further, by shifting the front wheel 51 rearward, the front wheel 51 can be brought close to the center of gravity of the vehicle, and the balance of the shared load of the front wheel 51 and the rear wheel 53 can be made evenly close. Furthermore, mass concentration can be achieved.

  In FIG. 1, an air cleaner 43 is disposed above the main frame 21 (above the crankcase 30). By arranging the air cleaner 43 in front of the vehicle, it is possible to easily introduce air from the front into the air cleaner 43, and it is possible to improve the air intake efficiency.

  An electrical component 42 such as a battery is disposed between the pair of body frames 22 below the air cleaner 43. It should be noted that a canister or an ABS unit may be disposed below the air cleaner 43 in addition to the electrical component 42. A fuel tank 40 is disposed behind the air cleaner 43 along the seat rail 23 and the backstay 24. In addition, a seat 41 is disposed behind the air cleaner 43 and above the electrical component 42 and the fuel tank 40.

  Further, an exhaust port (not shown) is provided on the side surface of the cylinder head 32 lying sideways, and the exhaust port is directed to the vehicle lower side. An exhaust pipe 6 is connected to the exhaust port. The exhaust pipe 6 extends downward from the side of the crankcase 30. A muffler 7 is connected to the lower end of the exhaust pipe 6 via an exhaust purification catalyst 44. The muffler 7 extends rearward along the lower side of the crankcase 30.

  The exhaust purification catalyst 44 is composed of, for example, a three-way catalyst, and converts pollutants (carbon monoxide, hydrocarbons, nitrogen oxides, etc.) in the exhaust gas into harmless substances (carbon dioxide, water, nitrogen, etc.). In this way, the exhaust gas is purified. By disposing the exhaust purification catalyst 44 at a position not far from the exhaust port, that is, on the upstream side of the exhaust, early activation of the exhaust purification catalyst 44 by exhaust heat can be realized, and the exhaust purification performance of the exhaust purification catalyst 44 It is possible to improve.

  As described above, in the present embodiment, the crankshaft 35, the main shaft 36, the drive shaft 37, and the pivot shaft 38 disposed in the crankcase 30 are arranged as described above, thereby shortening the wheel base and the swing arm 25. It is possible to achieve both extension. Thereby, while improving the steering stability of a vehicle, it is possible to comprise the power unit 3 compactly.

  In the above embodiment, the sports-type motorcycle 1 has been described as an example, but the present invention is not limited to this configuration. For example, the motorcycle 1 may be configured by an off-road type or tourer type motorcycle.

  In the above embodiment, a water-cooled single cylinder or multi-cylinder engine has been described as an example. However, the present invention is not limited to this configuration. For example, the engine may be air-cooled, and the number of cylinders and the arrangement of the cylinders can be changed as appropriate.

  Moreover, in the said embodiment, although the vehicle body frame 3 was comprised with the frame of the aluminum twin spar type or the diamond type, it is not limited to this structure. The body frame 3 may be another type of frame such as a cradle type or an underbone type.

  Moreover, in the said embodiment, although the cylinder block 31 and the crankcase 30 were comprised by separate components, it is not limited to this structure. The cylinder block 31 and the crankcase 30 may be composed of integrated parts.

  Moreover, in the said embodiment, although it was set as the structure by which the electrical component 42 is arrange | positioned behind the air cleaner 43, it is not limited to this structure. The front-rear relationship between the air cleaner 43 and the electrical component 42 may be reversed.

  Moreover, although the said embodiment demonstrated the case where it arrange | positions so that the axis C of the cylinder block 31 may become in parallel with the extension direction of the main frame 21, it is not limited to this structure. The axis C need not be completely parallel to the extending direction of the main frame 21, and the axis C and the extending direction of the main frame 21 may intersect.

  In the above embodiment, the pivot shaft 38 is disposed inside the triangle connecting the centers of the crank shaft 35, the main shaft 36, and the drive shaft 37. However, the present invention is not limited to this configuration. The pivot shaft 38 may be arranged on the side of the triangle or on the outside of the triangle.

  In the above embodiment, the pivot shaft 38 is disposed in front of the crank shaft 35. However, the present invention is not limited to this configuration. The pivot shaft 38 may be disposed in front of the drive shaft 37. Further, the positional relationship of the four axes is not limited to the above configuration, and can be changed as appropriate. Here, with reference to FIG. 2, the shaft arrangement | positioning which concerns on a modification is demonstrated. FIG. 2 (FIGS. 2A-C) is a schematic diagram showing variations of the shaft arrangement of the engine. In FIG. 2, only the positional relationship of four axes is shown for convenience of explanation.

  As shown in FIG. 2A, the main shaft 36 is disposed on the front lower side of the crank shaft 35, and the drive shaft 37 is disposed on the rear lower side of the crank shaft 35 and on the rear lower side of the main shaft 36. The pivot shaft 38 is located on the inner side of the triangle connecting the centers of the crank shaft 35, the main shaft 36, and the drive shaft 37, below the crank shaft 35, above the main shaft 36, and above the drive shaft 37. Has been placed.

  As shown in FIG. 2B, the main shaft 36 is disposed on the front lower side of the crank shaft 35, and the drive shaft 37 is disposed on the rear lower side of the crank shaft 35 and on the rear upper side of the main shaft 36. The pivot shaft 38 is located inside the triangle connecting the centers of the crank shaft 35, the main shaft 36, and the drive shaft 37, on the front lower side of the crank shaft 35, on the rear upper side of the main shaft 36, and on the front lower side of the drive shaft 37. Has been placed.

  As shown in FIG. 2C, the main shaft 36 is disposed on the front lower side of the crankshaft 35, and the drive shaft 37 is disposed on the front lower side of the crankshaft 35 and on the rear lower side of the main shaft 36. The pivot shaft 38 is located outside the triangle connecting the centers of the crank shaft 35, the main shaft 36, and the drive shaft 37, on the front lower side of the crank shaft 35, on the rear lower side of the main shaft 36, and on the rear upper side of the drive shaft 37. Has been placed. Even with these arrangements, the swing arm 25 can be extended. Note that the arrangement shown in FIG. 2 is merely an example, and the arrangement can be changed as appropriate without departing from the spirit of the technical idea of the present invention.

  Moreover, although the said embodiment demonstrated the structure in which the crankshaft 35 was provided on the extension line of the axis C of the cylinder block 31, it is not limited to this structure. For example, the engine may be an offset crank type engine in which the crankshaft 35 is offset from the axis C by a predetermined distance.

  Moreover, although this Embodiment and the modified example were demonstrated, what combined the said embodiment and modified example entirely or partially as another embodiment of this invention may be sufficient.

  The embodiments of the present invention are not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made 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 technological advancement or other derived technology, the method may be used. Accordingly, the claims cover all embodiments that can be included within the scope of the technical idea of the present invention.

  As described above, the present invention has the effect that the swing arm can be lengthened while shortening the wheel base, and is particularly useful for the vehicle structure of a motorcycle.

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 20 Head pipe 21 Main frame 3 Power unit 30 Crankcase 31 Cylinder block 35 Crankshaft 36 Main shaft 37 Drive shaft 38 Pivot shaft 43 Air cleaner 44 Exhaust purification catalyst

Claims (4)

A crankshaft extending in the left-right direction of the motorcycle,
A main shaft extending in the same direction as the crank shaft and transmitting rotation of the crank shaft;
A drive shaft extending in the same direction as the crankshaft and transmitting the rotation of the main shaft;
A pivot shaft extending in the same direction as the crankshaft and swingably supporting the swing arm,
The main shaft is disposed at the front lower side of the crankshaft,
The drive shaft is disposed below the crankshaft and behind the main shaft,
The vehicle structure of a motorcycle, wherein the pivot shaft is disposed inside a triangle connecting the centers of the crank shaft, the main shaft, and the drive shaft in a side view. It further includes a pair of left and right main frames extending rearward from the head pipe,
The cylinder block of the engine is sandwiched between the pair of left and right main frames, and is arranged so that an axial direction is parallel to an extending direction of the pair of left and right main frames. The motorcycle vehicle structure.   The vehicle structure of a motorcycle according to claim 2, further comprising an air cleaner disposed above the engine.   The vehicle structure for a motorcycle according to claim 2 or 3, further comprising an exhaust purification catalyst disposed below the engine.

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