JPH0811559B2 - Motorcycle rear suspension - Google Patents

Description

TECHNICAL FIELD The present invention relates to a so-called single suspension type suspension having one cushion unit adopted as a rear wheel suspension system of a motorcycle.

[Conventional technology]

In recent motorcycles, a single suspension type suspension is often adopted as a rear wheel suspension device. As an example of this single suspension type rear suspension,
For example, there is one disclosed in Japanese Patent Laid-Open No. 57-58579, which has a suspension link consisting of a tension rod and a link arm interposed between a vehicle body frame and a rear fork, and the suspension link and the vehicle body. In a cushion unit provided between the frame and the frame, the link is composed of a pair of left and right connecting arms, which are respectively connected to the left and right legs of the rear fork.

[Problems to be solved by the invention]

By the way, when the suspension link is arranged below the rear fork and one cushion penetrating below the rear fork is connected to this link, the connecting portion is located at the lower part of the vehicle body, so there is a risk of damage due to flying stones or the like. There is.

In order to avoid this damage problem, it is possible to use a pair of left and right mufflers that are located below the vehicle body frame as protective members. However, flying stones do not pass between the left and right mufflers. Have to be close together. However, in the case of the rear suspension described in the above publication, the suspension link connected to the left and right legs of the swing arm is large in size and has the same width as the rear fork. When it moves up and down, it may interfere with the muffler.

The present invention has been made in order to solve such a problem, and the connecting portion between the cushion unit and the suspension link can be sufficiently protected by a pair of left and right mufflers below the vehicle body frame, and from the road surface. It is an object of the present invention to provide a rear suspension of a motorcycle that does not break even under a large impact load, has high torsional rigidity, and contributes to improved running performance.

[Means for solving problems]

The present invention provides a relay between a lower portion of a vehicle body frame in which a pair of left and right mufflers are arranged and a lower surface of a cross member that integrally connects the left and right swing arms of a rear fork on the front side of a rear wheel. A suspension link consisting of an arm and a connecting rod is installed, and the large diameter part of one cushion unit is located on the left side in front of the cross member.
In a rear suspension of a motorcycle in which the right swing arms are pierced downwards in a forward tilted state, the upper part of the cushion unit is connected to the vehicle body frame, and the lower part is connected to the suspension link, the cross section shape of the swing arm is a vertically long rectangular shape. In addition to the above, the cross-section of the cross member is formed into a rectangular closed cross section that is approximately the same height as the swing arm,
An inclined wall parallel to the outer peripheral surface of the large diameter portion of the cushion unit is provided under the front wall of the cross member, and a pair of left and right plate-shaped rear brackets are arranged downward from the bottom surface of the cross member at intervals approximately equal to the rear wheel width. When projecting, the rear bracket is viewed from the side of the vehicle, the front edge is located in the vicinity of the downward extension surface of the inclined wall, the rear edge rises above the lower surface of the cross member, and the lower portion of the rear wall of the cross member And a rear end of the rear arm having a pair of left and right relay arms swingably connected to the inside of the lower end of the rear bracket, and a connecting rod consisting of one rod inside the front end of the relay arm. The bifurcated portion formed at the rear end portion is connected via a connecting shaft, the front end portion of the connecting rod is swingably connected to the lower portion of the vehicle body frame, and the lower portion of the cushion unit is The exhaust pipe is connected to the inside of the vehicle by the connecting shaft, and the muffler is expanded in a substantially tapered shape from the exhaust port toward the center of the front-rear direction of the vehicle, while being reduced in a substantially tapered shape from the substantially center of the vehicle toward the rear of the vehicle, and in the vehicle width direction. The left and right expansion chambers are arranged so as to be close to each other, and the connecting portion between the suspension link and the cushion unit is located in the tapered reduction section of the left and right expansion chambers. It is characterized by being covered with left and right expansion chambers.

[Action]

According to the rear suspension of the motorcycle of the present invention, the lower part of the connecting portion between the suspension link and the cushion unit is covered with the expansion chamber,
Since the expansion chamber is made to function as a protective member, the connecting portion can be protected from flying stones and the like.

In this case, since the relay arm is supported by the pair of left and right rear brackets protruding from the lower surface of the cross member at intervals smaller than the rear wheel width, the width of the relay arm is narrowed, and the expansion chambers are arranged close to each other. However, these do not interfere with the relay arm.

Further, since the connecting portion between the cushion unit and the suspension link is located in the tapered reduction portion while avoiding the maximum diameter portion of the expansion chamber, it is possible to suppress the expansion of the expansion chamber and secure the bank angle.

Since the inclined wall that is parallel to the outer peripheral surface of the large diameter portion of the cushion unit is provided below the front wall of the cross member, the cross member can be formed into a rectangular closed cross section having substantially the same height as the swing arm. The rigidity of the member can be improved.

The pair of left and right rear brackets, when viewed from the side, have a front edge located near a downward extension surface of the inclined wall of the cross member, a rear edge rising above the lower surface of the cross member, and a cross member. Since it is formed so as to overlap with the lower portion of the rear wall of the member, the rear bracket arranged in the limited space between the large diameter portion of the action unit and the rear wheel can be enlarged.

A large load acts on the support point of the relay arm of the rear bracket via the relay arm due to the impact due to the unevenness of the road surface, but as described above, the rigidity of the cross member and the rear bracket can be improved, and the large load can be withstood. be able to.

That is, the relay arm support point is located below the cross member, and the line of action of the load is separated from the center of the cross section of the cross member, so that a large moment acts on the cross member and the rear bracket. But,
As described above, in the present invention, since the cross-sectional shape of the cross member is large and the rear bracket is also large, the cross member is not damaged by the moment.

Further, since the pair of left and right rear brackets are arranged at an interval substantially equal to the rear wheel width, the portion where the rear edge of the rear bracket overlaps the lower part of the rear wall of the cross member is the maximum diameter portion of the rear wheel. Since they are located on both sides, even if the rear wheel is brought close to the rear wall of the cross member, the overlapping portion does not interfere with the outer peripheral surface of the rear wheel.

Furthermore, the cross member is originally used to increase the torsional rigidity of the rear fork. In the present invention, the cross-section of the cross member is formed into a rectangular closed cross-section having substantially the same height as the swing arm. Since the cross-section is large as described above, the torsional rigidity of the rear fork is increased, and the vehicle travels. The performance can be improved.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention, in which reference numeral 1 denotes a two-wheeled vehicle to which a rear suspension according to the present embodiment is applied, and a front wheel 3 is supported on a front end of a body frame 2 of the two-wheeled vehicle. A front fork 4 is rotatably attached to the left and right, a rear fork 6 that supports a rear wheel 5 is attached to the rear end portion so as to be vertically swingable, and a fuel tank 7 and a seat 8 are attached to the upper portion. Further, a water-cooled two-cycle two-cylinder engine 9 is mounted substantially in the center of the body frame 2.

A rear suspension 10 composed of a suspension link 11 and a cushion unit 12 is arranged near the connecting portion between the rear fork 6 and the body frame 2.
The suspension link 11 has a link shape in which a relay arm 15 and a connecting rod 16 are rotatably connected by a connecting shaft 17.

The relay arm 15 has a U-shape in a plan view, and a pivot pipe 15c thereof is inserted between rear brackets 6e and 6f projecting at a predetermined interval in the center of a lower surface of a cross member 26 of the rear fork 6 described later. That is, it is sandwiched by the brackets 6e and 6f, and is pivotably supported by the brackets 6e and 6f by a pivot shaft 19.
The bifurcated rear end of the connecting rod 16 is rotatably fitted to the connecting shaft 17, and the front end is fixed to the lower end of the support bracket 2a of the vehicle body frame 2. It is inserted into the front bracket 2b and is swingably supported by the front pivot shaft 20.

The cushion unit 12 is a shock absorber 21.
A coil spring 22 is mounted between the upper and lower flange portions of the rear fork, and the coil spring 22 is disposed between the pivot pipe 6c of the rear fork 6 and the cross member 26 in a vertical direction and inclined forward.
The lower end 21a of the shock absorber 21 is rotatably connected to the connecting shaft 17 and the upper end 21b.
Is also rotatably supported by a cushion bracket 2c formed at the upper end of the support bracket portion 2a.

The rear fork 6 integrally connects the front ends of the left and right swing arms 6a and 6b made of square pipes extending in the vehicle front-rear direction with a pivot pipe 6c, and a cross member between the rear portions of the pivot pipe 6c. It is one that is integrally connected with 26. The pivot pipe 6c of the rear fork 6 is swingably supported by a pivot shaft 13 in the vicinity of the center of the support bracket 2a, and the rear end portion between the left and right swing arms 6a, 6b is supported by a wheel shaft 14 at the rear. A wheel 5 is rotatably supported.

The cross member 26 is a pentagonal tubular body in cross section. That is, the cross member 26 is connected to the upper and lower walls 26a and 26b, the rear wall 26d vertically formed between the rear ends of the upper and lower walls 26a and 26b, and the front end of the upper wall 26a. A front wall 26c formed vertically downward, and a tubular body having a pentagonal cross section that connects the lower end of the front wall 26c and the front end of the lower wall 26b, and is composed of an inclined wall 26e parallel to the cushion unit 12, The inclined wall 26e serves as an escape for avoiding interference with the cushion unit 12. The cross member 26 occupies almost the entire gap between the rear wheel 5 and the cushion unit 12.

Further, mufflers 23, 24 are connected to the left and right cylinder blocks of the engine 9, and these mufflers 23, 24 are connected.
Is composed of expansion chambers 23b, 24b having an elliptical cross section formed subsequent to the exhaust pipes 23a, 24a and having a larger diameter toward the center in the longitudinal direction, and silencers 23c, 24c connected to the rear ends thereof. There is. The front of the expansion chambers 23b, 24b is the crankcase 9
It is located below a, and the central portion is located below the vehicle body frame 2, that is, in the immediate vicinity of the side of the suspension link 11, so that the lower portions of the mufflers 23 and 24 have substantially the same width as the vehicle body frame 2. ing.

 Next, the function and effect will be described.

In this embodiment, the relay arm of the suspension link 11
Since the 15 is supported by the support brackets 6e, 6f projectingly provided in the center of the lower surface of the cross member 26 of the rear fork 6, the suspension link 11 of the above-mentioned conventional rear fork is supported by the left and right swing arms. The width can be made very narrow, so that the mounting space for the muffler and the like becomes large and the degree of freedom in layout is improved. Therefore, the mufflers 23, 24 can be arranged closer to the center position of the vehicle body, and the vehicle width can be narrowed by that amount, and, for example, the bank angle during cornering can be increased.

In this case, since the relay arm 15 is located below, the moment arm is lengthened, and a large torsion moment acts on the cross member 26 of the rear fork 6 due to the impact from the unevenness of the road surface. However, since the cross member 26 of this embodiment has a pentagonal cross section,
In the space sandwiched between the cushion unit 12 and the rear wheel 5, a larger cross-sectional area can be secured than in the case of a rectangle or a circle, and the torsional rigidity is high accordingly, so that it is possible to withstand the large torsional moment.

〔The invention's effect〕

As described above, according to the motorcycle rear suspension of the present invention, since the connecting portion between the suspension link and the cushion unit is disposed between the expansion chambers, the expanding chamber can protect the connecting portion from flying stones and the like. Has the effect that
Further, in this case, since the relay arm is supported by the pair of left and right rear brackets protruding from the lower surface of the cross member at an interval substantially equal to the rear wheel width, the width of the relay arm is narrowed, and the relay arm is positioned below the body frame. Even if the expansion chambers are arranged close to the left and right so as to function as a protection member against flying stones, the relay arms do not interfere with them.

Further, in the present invention, since the connecting portion is located in the tapered reduction portion while avoiding the maximum diameter portion of the expansion chamber, there is an effect that expansion of the expansion chamber can be suppressed and a bank angle can be secured.

Further, an inclined wall parallel to the outer peripheral surface of the large diameter portion of the cushion unit is provided below the front wall of the cross member, and the pair of left and right rear brackets have a front edge when viewed from the side, and the inclined wall of the cross member is the inclined wall. It is located near the downward extension surface of the cushion member so that its rear edge rises above the lower surface of the cross member and overlaps with the lower part of the rear wall of the cross member. The cross-sectional shape of the cross member and the rear bracket arranged in the limited space can be increased, and the rigidity that can withstand the load acting on the support point of the relay arm of the rear bracket can be secured.

Further, since the pair of left and right rear brackets are arranged at an interval substantially equal to the rear wheel width, the portion where the rear edge of the rear bracket overlaps the lower portion of the rear wall of the cross member is located on both sides of the maximum diameter portion of the rear wheel. Therefore, even if the rear wheel is brought close to the rear wall of the cross member, the overlapping portion does not interfere with the outer peripheral surface of the rear wheel.

Furthermore, since the cross-sectional shape of the cross member is formed to be a rectangular closed cross section having substantially the same height as the swing arm and a large cross-sectional area, the torsional rigidity of the rear fork is increased and the running performance of the vehicle can be improved. effective.

[Brief description of drawings]

1 is a sectional side view of a rear suspension for a motorcycle according to an embodiment of the present invention, FIG. 2 is a plan view of a rear fork portion thereof, FIG. 3 is a side view of a motorcycle to which the above embodiment is applied, and FIG. The figure is a plan view showing the arrangement of the rear suspension and the muffler. In the figure, 1 is a motorcycle, 2 is a body frame, 6 is a rear fork, 6a and 6b are left and right swing arms, 10 is a rear suspension, 11 is a suspension link, 12 is a cushion unit, 15 is a relay arm, and 16 is a connectin. Grod, 26 is cross beam, 26a, 26b are upper and lower walls, 26c, 26d
Are front and rear walls, and 26e is an inclined wall.

Continuation of the front page (56) Reference JP-A-60-67287 (JP, A) JP-A-56-149273 (JP, A) JP-A-60-50088 (JP, A) JP-A-60-56690 (JP , A) JP 60-99786 (JP, A) JP 60-6088 (JP, A) JP 58-116287 (JP, A) JP 58-39577 (JP, A) JP 58-20585 (JP, A) Actual public Sho 59-33744 (JP, Y2)

Claims (1)

[Claims] Claims: 1. Between a lower portion of a vehicle body frame on which a pair of left and right mufflers are arranged and a lower surface of a cross member integrally connecting left and right swing arms of a rear fork at a front side of a rear wheel, A suspension link composed of a relay arm and a connecting rod is provided, and the large diameter part of one cushion unit is penetrated downward between the left and right swing arms on the front side of the cross member in a forward tilted state. A rear suspension of a motorcycle in which an upper portion of the cushion unit is connected to the body frame and a lower portion of the cushion unit is connected to the suspension link, and the left and right swing arms have a cross-sectional shape of a vertically long rectangular shape, The cross-sectional shape of the member is formed into a rectangular closed cross section that is approximately the same height as the left and right swing arms, and An inclined wall, which is substantially parallel to the outer peripheral surface of the large-diameter portion of the cushion unit, is provided in the lower part of the wall, and a pair of left and right plate-shaped rear brackets are projected downward from the lower surface of the cross member at intervals substantially equal to the rear wheel width. When the rear bracket is viewed from the vehicle side, the front edge is located in the vicinity of the downward extension surface of the inclined wall, the rear edge rises above the lower surface of the cross member, and the rear wall of the cross member is provided. It is formed so as to overlap the lower part, and the rear ends of the pair of left and right relay arms are swingably connected to the inside of the lower end of the rear bracket,
Inside the front end of the relay arm, a bifurcated part formed at the rear end of the connecting rod consisting of one rod is connected via a connecting shaft, and the front end of the connecting rod is connected to the lower part of the body frame. The cushion unit is swingably connected, the lower portion of the cushion unit is connected to the inside of the forked portion by the connecting shaft, and the left and right mufflers are enlarged in a substantially tapered shape from the exhaust port toward the center of the vehicle front-rear direction. Suppose that the left and right expansion chambers are arranged so as to be reduced in a substantially tapered shape from the substantially central portion of the vehicle body toward the rear portion of the vehicle body, and are arranged close to each other in the vehicle width direction,
A rear suspension for a motorcycle characterized in that the connecting portion between the suspension link and the cushion unit is located in the tapered reduction section of the left and right expansion chambers, and the lower portion of the connecting portion is covered by the left and right expansion chambers.