JPH066438B2 - Wheel mounting structure for rear wheels of motorcycles - Google Patents

Description

The present invention relates to a wheel mounting structure for a rear wheel of a motorcycle.

(Prior art and its problem) In a motorcycle having a cantilever type swing arm, conventionally, a brake disc is fixed to an axle of a rear wheel and a caliper is fixed to a swing arm. Since it is necessary to secure a mounting space for the caliper, an offset method is adopted in which the center part of the rear wheel is deformed and the center part of the wheel is attached to the axle of the rear wheel at a position deviated from the center of the width direction of the vehicle body. Was there.

However, in such a conventional configuration, since the weight of the brake disc and the caliper is applied to the swing arm, the unsprung load of the rear wheel becomes heavy. Another prior art is Jitsuko Sho 53-53237.

On the other hand, there is a structure in which a brake disc is fixed to a pivot shaft of a swing arm and a caliper is fixed to a body frame side as in JP-A-53-142739, but between the bearings of the pivot shaft. The brake shaft and the sprocket for transmitting the chain are both attached, and it is a structure for supporting the pivot shaft in which the load of the brake and the chain transmission load are concentrated on a certain portion of the pivot shaft, which is difficult to attach or inspect from the outside.

(Means for Solving the Problems) In order to solve the above problems, a wheel mounting structure for a rear wheel of a motorcycle according to the present invention is a cantilever which is rearward of an engine, is parallel to an output shaft of the engine, and is rotatable about an axis. In a motorcycle having a pivot shaft of a swing arm and transmitting power from an output shaft of the engine to an axle of a rear wheel through the pivot shaft, a brake disc is fixed to the pivot shaft concentrically and braking is performed. A caliper that sometimes clamps the brake disc to restrict its rotation is fixed to the body frame, and the center of the rear wheel is attached to the axle of the rear wheel at the center of the motorcycle in the width direction of the motorcycle. It is a thing.

(Operation) The weights of the brake disc and the caliper of the disc brake device for the rear wheel are supported by the vehicle body frame without being added to the swing arm. Therefore, the unsprung load of the rear wheel is lightened, and the wheel of the rear wheel is not offset, so that the twist of the wheel due to the twist of the swing arm is reduced.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a cross-sectional plan view of a main part of a motorcycle that adopts a wheel mounting structure for a rear wheel according to an embodiment of the present invention, and FIG. 2 is a schematic vertical sectional front view of FIG. 1 and FIG.
Reference numeral 1 denotes an engine crankcase, and from the crankcase 1, an engine output shaft 2 is provided on the left side (lower side in FIG. 1) in the traveling direction of the motorcycle indicated by an arrow A.
Of the output shaft 2 has a drive sprocket 3 fixed thereto.

A pivot shaft 5 is arranged in parallel with the output shaft 2 at the rear of the crankcase 1, and an annular collar portion 6 is integrally provided on the outer periphery of one end of the pivot shaft 5 so as to project. A male screw portion 7 is screwed on the outer circumference of the end portion. A cylindrical first sleeve 8 is fitted to the outer periphery of the intermediate portion of the pivot shaft 5, and inner races of the ball bearings 9 and 10 are fitted and fixed at positions on both sides of the first sleeve 8. Has been done. The outer races of these ball bearings 9 and 10 are fitted and fixed to the inner circumferences of both ends of a cylindrical second sleeve 11 which is loosely fitted to the outer circumference of the first sleeve 8. , Are fixed to the vehicle body frame 14 by nuts 12 and 13 which are screwed to male screw portions screwed on the outer circumferences of both ends. Reference numerals 15 and 16 are oil seals. That is, the pivot shaft 5 is connected to the body frame 1 via the second sleeve 11 and the ball bearings 9 and 10.
4 is rotatably supported.

At the outer circumference of one end of the pivot shaft 5, there is a first outer circumference.
A sprocket cylinder 20 in which the sprocket 18 and the second sprocket 19 are integrally projected is fixedly fitted, and one end of the sprocket cylinder 20 abuts on the flange portion 6 of the pivot shaft 5 and the other end. Touches the inner race of the ball bearing 9. The first sprocket 18 and the second sprocket 19 of the sprocket cylinder 20 are provided so as to project at a predetermined interval in the axial direction. An annular brake disc receiver 21 is screwed onto the male screw portion 7 of the pivot shaft 5, and a nut 22 is screwed onto the male screw portion 7 at an axially outer side of the brake disc receiver 21. Two disc-shaped brake discs 23 are concentrically fitted and fixed to the outer periphery. Then, the brake disc 23 is inserted into the body frame 14 at the time of braking so that the brake disc 23
A caliper 24 that restricts the rotation of the is fixed.

Reference numeral 26 denotes a chain cover that also serves as a cantilever swing arm. The chain cover 26 is located at the inner side closer to the vehicle body center C in the vehicle width direction indicated by the alternate long and short dash line with reference to the position of a second chain described later. It is divided into a side portion 27 and a front side portion 28 far from the vehicle body center C. The front side portion 28 is formed by a plurality of bolts and nuts (not shown) in the back side portion 27.
Installed on. The back side portion 27 and the front side portion 28 are cast products made of an aluminum alloy and are integrally molded. The first tubular flange portion 29 located at the front end portion of the back side portion 27 has a third sleeve whose both ends are closely opposed to the vehicle body frame 14 and which fits on the outer circumference of the second sleeve 11. Needle bearings 31, 32 are interposed between the first tubular flange portion 29 and the third sleeve 30 so as to be loosely fitted around the outer periphery of the sleeve 30.
As a result, the chain cover 26 is positioned so as to be restricted from moving in the width direction of the vehicle body, that is, in the axial center direction of the pivot shaft 5, and is swingably supported about the axial center of the pivot shaft 5.

A rear wheel axle 39 is rotatably supported via ball bearings 37 and 38 on the inner circumference of the second tubular flange portion 36 located at the rear end portion of the back side portion 27 of the chain cover 26. ing. Reference numeral 40 is a fourth sleeve, and 41 and 42 are oil seals.

A male screw portion 44 is screwed on the outer periphery of one end of the axle 39, and an annular sprocket receiver 45 is screwed and fixed to the male screw portion 44. An annular third sprocket 46 is fixed to the outer circumference of the sprocket receiver 45 by a plurality of bolts 47. The axle 39
A male screw portion 49 is screwed on the outer circumference of the other end of the wheel, and the center portion of a rear wheel 50 is screwed into the male screw portion 49. It is fixed at 39. The center portion of this wheel 50 is not deformed and has a linear cross-sectional shape, and the center portion is attached to the axle 39 at the position of the vehicle body center C. Tires 53 are attached to the outer periphery of the wheel 50.

An endless first chain 55 as a power transmission device is mounted between the drive sprocket 3 and the first sprocket 18, and the second sprocket 19 and the third sprocket 46 are connected to each other. An endless second chain 56 is mounted between them. And the second
The sprocket 19, the third sprocket 46, and the second chain 56 are covered by the chain cover 26, and the front end of the chain cover 26 is open. As is apparent from FIG. 2, the chain cover 26 has spaces 57 and 58, and the back side portion 27 has vibration prevention for preventing vibration of the second chain 56. The members 59, 60, 61, 62 are attached. These vibration preventing members 59, 60, 61, 62 are made of, for example, hard nylon, and are arranged close to each other above and below the second chain 56.

Reference numeral 64 denotes a bag-shaped cover body having an open rear end, which, like the chain cover 26, is divided into a back side portion 65 and a front side portion 66, and the back side portion 65 is fixed to the vehicle body frame 14. The front side portion 66 is fixed to the back side portion 65 by a plurality of bolts and nuts (not shown). The cover body 64 covers the drive sprocket 3 and the first chain 55, and the cover body 53 and the chain cover 26 allow the drive sprocket 3, the first chain 55, and the first sprocket to be covered. A closed space 67 is formed which surrounds 18, the second sprocket 19, the second chain 56, and the third sprocket 46. 2 shows the chain cover 26.
Also, the front side portions 28 and 66 are shown removed from the cover body 64.

Next, the operation will be described. The rotational power of the output shaft 2 of the engine is
It is transmitted to the pivot shaft 5 via the drive sprocket 3, the first chain 55, the first sprocket 18, and the sprocket cylinder 20, and the turning force of the pivot shaft 5 is transmitted to the sprocket cylinder 20 and the second sprocket 19.
Is transmitted to the axle 39 of the rear wheel via the second chain 56 and the third sprocket 46. Therefore the axle 39
Rotates and the wheel 50 rotates integrally with the axle 39, so that the motorcycle travels in the direction of arrow A. Here, when the impact from the road surface is transmitted to the rear wheels, the chain cover 26, which also functions as a cantilever type swing arm, causes the pivot shaft 5 to move.
It swings about its axis and the swing center, and the impact transmitted to the vehicle body frame 14 is mitigated by the interaction with the rear suspension. During braking, the piston of the caliper 24 operates and the pad is pressed against the brake disc 23, and the rotation of the brake disc 23 is restricted. This restricting force is generated by the pivot shaft 5, the second sprocket 19 of the sprocket cylinder 20, the second chain 56, and the third sprocket 46.
Is transmitted to the axle 39 via and to brake the rear wheels.

In this way, since the brake disc 23 is fixed to the pivot shaft 5 and the caliper 24 is fixed to the vehicle body frame 14, the mass can be concentrated, the unsprung load of the rear wheels is reduced, and the rear suspension system is Work efficiently. Further, since the brake disc 23 is fixed to the pivot shaft 5 and the caliper 24 is fixed to the vehicle body frame 14, the center portion of the wheel 50 of the rear wheel is attached to the axle 39 at the position of the vehicle body center C. Since the length can be shortened and the center portion of the wheel 50 need not be deformed, the unsprung load of the rear wheel can be reduced by weighing the axle 39 and the wheel 50, and at the same time, the wobbling of the wheel 50 due to the twist of the chain cover 26 can be realized. Get smaller. That is, conventionally, the center of the rear wheel is largely projected to the side opposite to the swing arm side, and the brake disc and the caliper are housed in this space. Has to use the offset method to attach to the axle of the rear wheel at the opposite side, and therefore the axle of the rear wheel becomes long and heavy, and the wheel becomes heavy because it deforms the wheel. However, such an inconvenience can be solved in the above embodiment. Sprocket tube 20
If the brake disc receiver 21 and the brake disc receiver 21 are arranged so as to be distributed to both ends of the pivot shaft 5, the protrusion length from the ball bearings 9 and 10 at both ends of the pivot shaft 5 is shortened, which is preferable in terms of layout and proper weight distribution. As a result, the pivot shaft 5 can be stably supported. Further, if the cantilever type swing arm swinging around the axis of the pivot shaft 5 is also used as the chain cover 26 as in the present embodiment, it is possible to realize weighting and reduce the number of parts, and You can secure a good riding position. That is, conventionally, when the chain cover is also used as a cantilever type swing arm, the chain cover is configured to swing around the output shaft of the engine. Therefore, the front end of the chain cover is attached to the crankcase of the engine. It is necessary to attach to the body frame at both sides of the engine, and the crankcase of the engine greatly extends to the right.Therefore, the attachment position on the right side of the chain cover must be extended further to the right than the crankcase. Therefore, there is a disadvantage that the position of the step is greatly extended to the left and right, and a good riding position cannot be obtained, but according to the above embodiment, the cantilever type swing arm is attached to the chain cover 26.
It is possible to solve the above-mentioned conventional drawbacks without impairing the effects of weighing and reducing the number of parts due to the combined use of the two. Further, as in this embodiment, the cover body 6
4 is provided, and by the cover body 64 and the chain cover 26, the drive sprocket 3, the first chain 55, the first sprocket 18, the second sprocket 19, and the second sprocket 18 are provided.
If a closed space 67 that surrounds the chain 56 and the third sprocket 46 is constructed, the first and second chains 5
5,56, etc. are not splashed with water, so that the lubricating oil lasts longer, the durability of each component is improved, and mud, dust, etc. may adhere to the first and second chains 55, 56, etc. Since it does not exist, the power loss is reduced, and further, the lubricating oil of the first and second chains 55, 56 and the like is not scattered and the crankcase 1 and the like are not polluted. Further, as in this embodiment, the vibration preventing members 59, 60, 61,
The provision of 62 is preferable because the vibration of the second chain 56 can be suppressed and the power loss can be further reduced.

(Other Embodiment) In the above embodiment, the cantilever type swing arm is also used as the chain cover 26, but the present invention is not limited to such a configuration, and the cantilever type swing arm is used. You may make it provide an arm and a chain cover separately.

In the above embodiment, the sprocket cylinder 20 is fixed to one end of the pivot shaft 5 and the brake disc receiver 21 is fixed to the other end of the pivot shaft 5. However, the present invention is not limited to such a configuration. Sprocket tube 20
Both the brake disc receiver 21 and the brake disc receiver 21 may be fixed to one end of the pivot shaft 5.

Further, in the above embodiment, the example in which the two brake discs 23 for the rear wheels are provided has been described, but the present invention is not limited to such a configuration, and one or three.
More than one brake disc 23 may be provided.

In the above embodiment, the first chain 55 is used to transmit the power from the drive sprocket 3 to the first sprocket 18, but the present invention is not limited to such a configuration, and Instead of the chain 55, another power transmission device such as a belt may be used.

Further, in the above-mentioned embodiment, the vibration preventive members 59, 60, 61, 62 are provided on the chain cover 26, but another structure may be used as the vibration preventive device for the second chain 56, and it is not always necessary to prevent the vibration. No device need be provided.

Further, in the above-mentioned embodiment, the back side portion 27 and the front side portion 28 of the chain cover 26 are respectively cast products made of aluminum alloy, but these may be metals other than aluminum alloy. Further, the front side portion 28 does not necessarily have to be a cast product, and may be formed of a synthetic resin other than metal, for example. Further, the chain cover 26 does not necessarily have to be divided into two, and the number of divisions may be set appropriately according to various design conditions.

Further, although the cover body 64 is provided in the above embodiment,
In some cases, for example, a motorcycle exclusively for traveling on a paved road may not be provided with the cover body 64.

(Effects of the Invention) As described above, according to the present invention, the pivot shaft of the cantilever type swing arm that is rotatable behind the engine in parallel with the output shaft of the engine and about the axis is supported via the bearing. Then, in a motorcycle that transmits power from the output shaft of the engine to the axle of the rear wheel via the pivot shaft, a sprocket cylinder for power transmission is fitted and fixed to one end of the pivot shaft, and the bearing is inserted. Then, a brake disc is concentrically fixed to the other end, and a caliper that clamps the brake disc during braking to regulate its rotation is fixed to the body frame, and the center portion of the wheel for the rear wheel is used for the motorcycle. Since it is attached to the axle of the rear wheel at the center of the vehicle in the width direction of the vehicle, the weight of the brake disc and caliper is not applied to the cantilever swing arm, and the mass can be concentrated. As a result, the unsprung load on the rear wheels is lightened, and the rear suspension system works efficiently, resulting in improved riding comfort. Also, by fixing the brake disc to the pivot shaft and fixing the caliper to the body frame,
Although the motorcycle uses a cantilever type swing arm, the center of the rear wheel is attached to the axle of the rear wheel at the center of the width of the vehicle, so the axle of the rear wheel can be shortened and the wheel can be shortened. Since it is not necessary to deform the central part of the wheel, the weight of the axle of the rear wheel and the weight of the wheel can be reduced to reduce the unsprung load of the rear wheel, and at the same time, the twisting of the wheel due to the twisting of the swing arm is reduced.

Further, since the sprocket cylinder 20 and the brake disc 23 are arranged separately on both axial ends of the pivot shaft 5, they are supported by a pair of left and right bearings (ball bearings 9 and 10) as shown in FIG. In this case, the protrusion length from the bearings (ball bearings 9 and 10) at both ends of the pivot shaft 5 can be shortened, the layout can be mounted in a well-balanced manner, and the weight distribution on the left and right is appropriate. A support structure for the shaft 5 can be provided.

In addition, the work of assembling and inspecting the brake and sprocket cylinder can be easily performed from the outside.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of a main part of a motorcycle which employs a wheel mounting structure for a rear wheel according to an embodiment of the present invention, and FIG. 2 is a schematic vertical sectional front view of the same. 2 ... Output shaft, 5 ... Pivot shaft, 9, 10 ... Ball bearing (bearing), 14 ... Body frame, 20 ... Sprocket cylinder, 23 ... Brake disc, 24 ... Caliper, 26 ... Chain cover (cantilever type swing arm) ,
39 ... Axle, 50 ... Wheel

Claims (2)

[Claims] 1. A pivot shaft of a cantilever type swing arm that is rotatable behind an engine in parallel with an output shaft of the engine and is rotatable about an axis thereof is supported through a bearing, and the output of the engine is output through the pivot shaft. In a motorcycle that transmits power from a shaft to a rear wheel axle, a sprocket cylinder for power transmission is fitted and fixed to one end of the pivot shaft, and the brake disc is concentrically formed at the other end with the bearing interposed. A caliper that fixes and clamps the brake disc during braking to regulate its rotation is fixed to the body frame, and the center of the rear wheel is located at the center of the body in the width direction of the motorcycle. A wheel mounting structure for the rear wheels of a motorcycle characterized by being mounted on an axle. 2. The cantilever type swing arm also serves as a chain cover for covering a chain for transmitting power from a pivot shaft to a rear wheel axle.
The wheel mounting structure for the rear wheel of the motorcycle according to the item.