JP2007296874A - Motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motorcycle capable of avoiding or suppressing transmission of vehicle width direction vibration to a vehicle body frame when the vehicle width direction vibration from a road surface is inputted into front wheels or rear wheels, particularly during cornering. <P>SOLUTION: This motorcycle 1 is provided with a front fork 3 supported to be steerable by a vehicle body frame 2, the front wheels 4 supported at a lower end part of the front fork 3 via a front axle 10, a rear arm 7 supported to be vertically oscillatable by the vehicle body frame 2, and the rear wheels 8 supported at a rear end part of the rear arm 7 via a rear axle 31. The motorcycle 1 is provided with a dynamic damper 30 absorbing the vehicle width direction vibration inputted in the front wheels 4 or the rear wheels 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motorcycle, and more particularly, to a dynamic damper that can absorb vibrations input to a wheel from a road surface.

In a motorcycle, in order to suppress vibration from the engine from propagating to the rear arm, a vibration isolating member made of a rubber damper is arranged and fixed in the rear arm (see Patent Document 1).
Japanese Patent Laid-Open No. 06-298149

  By the way, in the case of a motorcycle, the vehicle travels with the vehicle body tilted (banked) during cornering. In this bank state, vibration from the road surface is input to the rear wheels, for example. It is important to ensure the road surface followability of the tire by preventing this vibration from being propagated to the vehicle body frame via the rear arm. However, since the vibration in the bank state acts in the vehicle width direction, the structure described in the above-mentioned conventional publication cannot absorb such vibration in the vehicle width direction, and improvement of road surface followability in the bank state is expected. Can not.

  On the other hand, techniques are also used to improve road surface followability in bank conditions by reducing the lateral rigidity while maintaining the longitudinal rigidity and torsional rigidity of the body frame and rear arm, and by reducing the operating resistance of the front fork and rear cushion. ing. However, when the bank angle increases, the input direction from the road surface has a large angle with respect to the operating direction of the front fork and the rear cushion, and it is difficult to operate them smoothly. In addition, there is a limit to the method of reducing the lateral rigidity of the vehicle body frame and the rear arm, and a positive effect of absorbing vibration in the vehicle width direction cannot be expected.

  The present invention is a motorcycle capable of avoiding or suppressing propagation of vehicle width direction vibration to a vehicle body frame when vibration in the vehicle width direction from a road surface is input to a front wheel or a rear wheel, particularly during cornering. It is an issue to provide.

  The present invention includes a front fork supported to be steerable by a body frame, a front wheel supported by a lower end portion of the front fork via a front axle, a rear arm supported to be swingable up and down by the body frame, A motorcycle having a rear wheel supported at a rear end portion of the rear arm via a rear axle, comprising a dynamic damper that absorbs vibration in the vehicle width direction inputted to the front wheel or the rear wheel. It is said.

  According to the present invention, the vehicle is transmitted from the road surface to the vehicle body frame via the tire and the front fork or the rear arm since the dynamic damper for absorbing the vibration in the vehicle width direction input from the road surface is provided to the front wheel or the rear wheel. Vibration in the width direction can be absorbed, and road surface followability can be ensured when the vehicle body is largely banked during cornering.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIGS. 1-7 is a figure for demonstrating the motorcycle provided with the dynamic damper based on one Embodiment of this invention.

  In the figure, reference numeral 1 denotes a motorcycle having the following structure. A front fork 3 is pivotally supported by a head pipe 2a formed at the front end of the vehicle body frame 2 so as to be steerable left and right around a steering axis a. A front wheel 4 is pivotally supported by a front axle 10 at a lower end portion of the front fork 3, and a steering handle 5 is attached to the upper end portion.

  The engine unit 6 is suspended and supported by the main frame 2 b of the body frame 2. A rear arm 7 is supported by a rear arm bracket 2c formed so as to extend downward from the rear end portion of the main frame 2b so as to be swingable up and down. A rear wheel 8 is pivotally supported by a rear axle 31 at the rear end of the rear arm 7.

  A fuel tank 25 is mounted on the upper side of the main frame 2b, and a seat 26 is mounted on the rear side. Furthermore, the front fork 3 and the left and right sides of the engine unit 6 are surrounded by a vehicle body cover 9.

  The front fork 3 has a so-called fork shape in which a pair of left and right fork main bodies 3a, 3a are fixed with upper and lower brackets and the upper and lower brackets are connected to each other by a steering shaft. The steering shaft is pivotally supported by the head pipe 2a.

  The left and right fork main bodies 3a include an outer tube and an inner tube that is slidably inserted into the outer tube. Here, the front fork 3 of the present embodiment is a so-called inverted type in which the inner tube is disposed on the lower side, and the upper end portions of the left and right outer tubes having large diameters are interposed via the upper and lower brackets described above. Since it is supported by the body frame 2, the support rigidity can be increased accordingly. Further, since the front wheel 4 is supported by the light inner tube with a small diameter, the unsprung load is reduced accordingly and the road surface response is excellent.

  Axle mounting brackets 3b, 3b are integrally formed at the lower ends of the left and right fork bodies 3a, 3a, and the axle 10 is inserted through the left and right axle mounting brackets 3b, 3b and fixed with nuts. The front wheel 4 is rotatably supported by the axle 10 via a bearing.

  A front fender 13 is disposed on the front wheel 4. The front fender 13 has an arc shape, a tire cover portion 13a that covers the rear edge portion from the upper edge portion of the front wheel 4, and extends downward from the left and right side walls of the tire cover portion 13a and extends downward from the fork body 3a. And a fork cover portion 13b covering the front from the front. The fork cover portion 13b is bolted and fixed to the lower portion of the fork main body 3a.

  The left and right disc plates 11, 11 are bolted to the left and right end surfaces of the hub portion 4a of the front wheel 4. A brake caliper 12 of a hydraulic brake device is disposed on the rear edge of the disc plate 11 in the vehicle longitudinal direction. The brake caliper 12 is bolted and fixed to a caliper bracket 3c integrally formed so as to extend rearward from the axle mounting bracket 3b.

  The rear arm 7 includes a pair of left and right arm bodies 7a and 7a, and a head portion 7b that connects the front ends of the arm bodies 7a and 7a. The head portion 7b is supported on the pivot shaft 7c by the rear arm bracket 2c so as to swing up and down. A rear wheel 8 is pivotally supported by a rear end portion of the arm bodies 7a, 7a via a rear axle 31.

  The motorcycle 1 according to this embodiment includes a vertical dynamic damper 14 that absorbs vertical vibrations input from the road surface to the front wheels 4 at the front fork 3 portion, and a rear wheel from the road surface at the rear end portion of the rear arm 7. A lateral dynamic damper 30 that absorbs vibration in the vehicle width direction input to 8 is provided.

  First, the vertical dynamic damper 14 will be described in detail. A pair of left and right vertical dynamic dampers 14 and 14 are attached to the axle mounting brackets 3b and 3b of the left and right fork bodies 3a and 3a via brackets 21 and 21, respectively.

  As shown mainly in FIG. 2, the vertical dynamic damper 14 is located behind the fork main body 3a and on the inner side in the vehicle width direction of a straight line b parallel to the vehicle center line passing through the outer edge of the fork main body 3a in the vehicle width direction. It arrange | positions so that at least one part of the vertical dynamic damper 14 may be located.

  More specifically, the vertical dynamic damper 14 is vertically oriented so that its axis c is along a plane A perpendicular to the axle 10 and the axis c is substantially parallel to the axis d of the fork main body 3a. Has been placed. Note that the vehicle longitudinal direction position of the steering axis a of the front fork 3 is located between the fork main body 3 a and the vertical dynamic damper 14. In other words, the vertical dynamic damper 14 is arranged at the inner side in the vehicle width direction as much as possible and close to the steering axis a.

  The vertical dynamic damper 14 has a bottomed cylindrical casing 15 having a bottom wall 15a at one end (tip) and an opening 15b at the other end.

  A cap 16 is inserted into the opening 15b, is prevented from coming off by a circlip 16a, and is further sealed by an O-ring 16b. Reference numeral 16c denotes an air vent bolt.

  A cylindrical weight 17 is disposed in the casing 15, and guide pistons 18 and 18 are attached to both ends of the weight 17. Springs 19 and 19 are interposed between the piston 18 and the bottom wall 15 a and between the cap 16, and the weight 17 is urged to a substantially axial center of the casing 15.

  The casing 15 is filled with oil 20. When the weight 17 vibrates, the oil is placed in a spring arrangement chamber through a sliding gap between the piston 18 and the casing 15 and a slit (not shown) recessed in the axial direction on the outer surface of the piston 18. And move between the weight placement chamber. Therefore, the vertical dynamic damper 14 generates a damping force due to the movement of the weight 17 and a damping force due to the movement of the oil 20.

  Here, when setting the characteristics of the damping force due to the size of the weight 17 and the spring constant of the spring 19 and the damping force due to the movement of the oil 20, the natural frequency of the tire or the vehicle body among the vibrations input from the road surface. It is set so that nearby vibrations can be positively removed.

  In the vertical dynamic damper 14, the front end portion of the casing 15 is inserted into a mounting hole formed in the bracket 21, and a screw portion 15 c formed at the front end is screwed into the bracket 21. The bracket 21 is bolted and fixed to a caliper bracket 3c formed integrally with the axle mounting bracket 3b. Reference numeral 15d denotes a tool hooking portion formed into a hexagon for hooking a tool.

  Next, the lateral dynamic damper 30 will be described in detail. The lateral dynamic damper 30 is disposed on the rear axle 31 portion of the rear arm 7. The rear axle 31 is also used as a cylindrical casing of the horizontal dynamic damper 30. The rear axle 31 has a cylindrical shape having a latching portion 31a and an opening 31c at one end and a screw portion 31b and an opening 31d at the other end. The hooking portion 31 a has a quadrangular shape as viewed in the axial direction of the rear axle 31, and two sides thereof are in contact with protrusions formed on the rear arm 7. As a result, the rear axle 31 can be prevented from rotating when the rear axle 31 is attached to the rear arm 7.

  Caps 35 and 35 'are inserted into the openings 32c and 31d. The cap 35 'on the opening 31d side is axially positioned by the step 31e and sealed by the O-ring 35b. The cap 35 on the opening 31c side is prevented from coming off by a circlip 35a and sealed by an O-ring 35b. Incidentally, 35c is an air venting bolt, and 35d is a sealing gasket.

  A cylindrical weight 32 is disposed between the caps 35 and 35 ′ in the rear axle 31, and guide pistons 33 and 33 are attached to both ends of the weight 32. Springs 34, 34 are interposed between the pistons 33, 33 and the caps 35, 35 ', whereby the weight 32 is urged substantially in the axial direction of the rear axle 31. Here, the springs 34 and 34 are interposed between the cap 35 and the piston 33 in a state where the amount of vibration of the weight 32 is compressed, for example, a dimension slightly larger than ± 5 to 10 mm. The piston 33 is not always necessary. For example, both end portions of the weight 32 may be processed into the same shape as the piston by machining or the like.

  The rear axle 31 is filled with oil 36. When the weight 32 vibrates, the oil 36 springs through a sliding gap between the piston 33 and the rear axle 31 and a slit (not shown) recessed in the axial direction on the outer surface of the piston 33. Move between the placement room and the weight placement room. Therefore, the lateral dynamic damper 30 generates a damping force due to the movement of the weight 32 and a damping force due to the movement of the oil 36.

  Here, when setting the characteristics of the damping force due to the size of the weight 32 and the spring constant of the spring 34 and the damping force due to the movement of the oil 36, the vehicle width direction input from the road surface to the rear wheel 8 at a predetermined bank angle. Among the vibrations, the vibration is set so as to be able to positively remove vibrations near the natural frequency of the tire or the vehicle body.

  In the present embodiment, a lateral dynamic damper 30 is disposed between the rear end portions of the rear arm 7, and the damping force of the lateral dynamic damper 30 is applied to the tire and the vehicle body among the vibrations in the vehicle width direction input from the road surface. Since it is set to positively remove the vibration near the natural frequency of having it, it can attenuate the vibration in the vehicle width direction input to the rear wheel 8 while banking the vehicle during cornering and running. The road surface following ability can be improved.

  When the lateral dynamic damper 30 is provided, it has a cylindrical shape and is built in the rear axle 31, that is, it is disposed at the center of the rear wheel 8. Therefore, the greater the bank angle during cornering, the greater the vibration in the vehicle width direction. And the moving direction (attenuation direction) of the weight 32 and the like are approximated, so that the vibration in the vehicle width direction can be more reliably absorbed.

  Further, since the lateral dynamic damper 30 is disposed at a position close to the road surface called the rear axle 31, the position of the damper is close to the input position of the vehicle width direction vibration during cornering. Can be absorbed reliably.

  Further, since the lateral dynamic damper 30 is built in the rear axle 31, the damper 30 swings up and down together with the rear wheel 8 at the axial center of the rear wheel 8, and the vehicle is provided with the dynamic damper. The influence on the running characteristics can be reduced.

  Furthermore, since the lateral dynamic damper 30 is built in the rear axle 31, no extra arrangement space is required, and there is no problem of interference with surrounding vehicle parts.

  Further, since the lateral dynamic damper 32 is composed of the weight 32, the spring 34, the piston 33, and the oil 36, the damping characteristic can be tuned easily and surely as compared with the case where it is composed of an elastic body such as rubber. For example, by replacing the spring 34 with one having a different spring constant, the frequency of vibration to be absorbed can be set as appropriate. Further, the damping capacity can be appropriately set by exchanging the oil 36 with one having a different viscosity or exchanging the piston 33 with one having a different slit size.

  Further, in the present embodiment, the vertical dynamic damper 14 is disposed on the axle mounting bracket 3b of the fork main body 3a of the front fork 3, and the damping force of the dynamic damper 14 is the tire among the vertical vibrations input from the road surface. Since it is set to positively remove the vibration near the natural frequency of the car body, the road surface followability can be improved.

  Further, when the vertical dynamic damper 14 is provided, it is formed into a cylindrical body, arranged along the fork main body 3a, and attached to the axle mounting bracket 3b, so that vibrations in the vertical direction from the road surface can be more reliably absorbed. It is easy to secure an arrangement space for the vertical dynamic damper 14, and interference with surrounding components can be avoided.

  Further, since the vertical dynamic damper 14 is arranged behind the fork main body 3a, that is, on the side where the steering axis a is arranged, the dynamic damper 14 can be arranged near the steering axis a, and the dynamic damper 14 is provided. Therefore, the influence on the rotational moment of the steering handle 5 and the pitching inertia moment of the vehicle can be minimized. In this case, since a pair of left and right dynamic dampers are provided and arranged so as to be bilaterally symmetric, it is possible to avoid the influence on the left and right weight balance and thus the running characteristics of the vehicle.

  Furthermore, since the vertical dynamic damper 14 is arranged in the vicinity of the front axle 10 and the horizontal dynamic damper 30 is built in the rear axle 31, it is possible to distribute relatively heavy dampers in front of and behind the motorcycle 1. In addition, the weight balance in the front-rear direction of the motorcycle 1 becomes good, and the steering stability can be kept good.

  In the above embodiment, the lateral dynamic damper 30 is built in the rear axle 31. However, the lateral dynamic damper of the present invention can also be built in, for example, the front axle 10, and of course both the rear axle 31 and the front axle 10. You may be prepared for.

  Moreover, in the said embodiment, although the horizontal dynamic damper 30 was incorporated in the axle shaft, you may arrange | position the horizontal dynamic damper of this invention in parts other than an axle shaft.

1 is a left side view of a motorcycle according to an embodiment of the present invention. It is the II-II sectional view taken on the line of FIG. 2 which shows the arrangement | positioning state of the vertical dynamic damper of the said embodiment. It is a cross-sectional side view of the vertical dynamic damper. It is a left view which shows the arrangement | positioning state of the said vertical dynamic damper. It is a side view of the rear axle which incorporates the horizontal dynamic damper of the above-mentioned embodiment. It is a cross-sectional side view of the said horizontal dynamic damper. It is an exploded view of the said horizontal dynamic damper.

Explanation of symbols

1 Motorcycle 2 Body frame 3 Front fork 4 Front wheel 7 Rear arm 8 Rear wheel 10 Front axle 30 Lateral dynamic damper (rear dynamic damper)
31 Rear axle (casing)
32 Weight 34 Spring (biasing member)

Claims (7)

A front fork supported to be steerable by a body frame, a front wheel supported by a lower end portion of the front fork via a front axle, a rear arm supported to be vertically swingable by the body frame, and a rear arm of the rear arm In a motorcycle having a rear wheel supported at the end via a rear axle,
A motorcycle comprising a dynamic damper that absorbs vibration in a vehicle width direction input to the front wheel or the rear wheel.   The motorcycle according to claim 1, further comprising a front dynamic damper that absorbs vibrations in a vehicle width direction input to the front wheels.   The motorcycle according to claim 2, wherein the front dynamic damper is disposed in the front axle.   The motorcycle according to claim 1, further comprising a rear dynamic damper that absorbs vibrations in a vehicle width direction input to the rear wheel.   The motorcycle according to claim 4, wherein the rear dynamic damper is disposed in the rear axle.   6. The front and rear dynamic dampers according to claim 3, wherein the front and rear dynamic dampers include a cylindrical casing, a weight disposed in the casing, and a biasing member that biases the weight toward a predetermined position in the axial direction. A motorcycle characterized by comprising:   The motorcycle according to claim 6, wherein the front axle and the rear axle are also used as a casing of the dynamic damper.

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