JP2005041382A - Rear wheel suspending device of motorcycle or the like - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost by using a swing arm as a cylinder, in a rear wheel suspending device of a motorcycle or the like. <P>SOLUTION: In the rear wheel suspending device 10 of the motorcycle or the like, the upper end of a first link 31 is rockably pivoted in an intermediate part of the swing arm 14, the front end of a second link 32 is rockably pivoted in a lower position of a pivot shaft 12 in a vehicle body side frame 11, the rear end of a third link 33 is rockably pivoted at the lower end of the first link 31, and the rear end of the second link 32 is rockably pivoted in an intermediate part of the third link 33. An end projecting from a cylinder hole 21 of a piston rod 23 is rockably pivoted at the front end of the third link 33, and the front end of the third link 33 is arranged at a position over the straight line c connecting the lower end of the first link 31 to the front end of the second link 32 at the maximum stretching time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rear wheel suspension device such as a motorcycle.

  As a rear wheel suspension device such as a motorcycle described in Patent Document 1, there is the following. That is, Patent Document 1 discloses a cushion unit 34 including a cylinder portion 41 and a piston rod 42 attached to a piston (not shown) movably accommodated in the cylinder portion 41. The upper end of the cushion unit 34 is swingably attached to the upper bracket 36 of the swing arm 32, and the lower end attaching portion 43 is attached to the link mechanism 37.

  The reason why the upper end of the cushion unit 34 is swingably attached to the swing arm 32 is as follows.

That is, the connecting portion of the first link 51 and the cushion unit 34 constituting the link mechanism 37, that is, the third shaft 58 moves in a circular arc around the first shaft 56 in FIGS. 2 and 3 of Patent Document 1. Arc movement is performed together with the link 51. Therefore, in order to absorb this circular motion, the upper end mounting portion 46 of the cushion unit 34 needs to be swingably mounted on the upper bracket 36 of the swing arm 32.
JP 2002-68066 (3 pages, FIG. 2, FIG. 3)

  Recently, motorcycles have been requested to reduce costs. For this reason, it is conceivable to reduce the number of parts and reduce the cost by forming a cylinder hole in the swing arm 32 as described in Patent Document 1 and using the swing arm 32 as a cylinder.

  However, when a cylinder hole is formed in the swing arm 32 and the swing arm 32 is used as a cylinder, the cylinder hole cannot swing with respect to the swing arm 32. The piston rod to be slid cannot slide.

  An object of the present invention is to reduce costs by using a swing arm as a cylinder in a rear wheel suspension device such as a motorcycle.

  According to the first aspect of the present invention, a rear wheel suspension such as a motorcycle in which a front end portion of a swing arm is swingably attached to a pivot shaft provided on a vehicle body side frame, and a rear wheel is rotatably supported on the rear end portion of the swing arm. In the apparatus, in the vertical direction in the swing arm, a cylinder hole having a lower end is formed, and a piston rod is inserted into the cylinder hole through a guide member provided in the opening of the cylinder hole. A piston provided at the insertion end of the piston rod is slidably contacted in the cylinder hole, an oil chamber defined by the piston is provided in the cylinder hole, and an upper end of the first link is provided at an intermediate portion of the swing arm. The front part of the second link is pivotally attached to the lower position of the pivot shaft in the vehicle body side frame, and the third end is pivotally attached to the lower end part of the first link. Back end of link Is pivotally attached to the intermediate portion of the third link, and the rear end portion of the second link is pivotally attached, and the front end portion of the third link projects from the cylinder hole of the piston rod. And the front end portion of the third link is located above the straight line connecting the lower end portion of the first link and the front end portion of the second link at the maximum extension. It arrange | positions so that it may be located in.

  Since the vehicle body side frame, the swing arm, the piston rod, and the first to third links are connected as described above, the piston rod remains on the center axis of the cylinder hole even if the cylinder hole cannot swing relative to the swing arm. The piston rod and the piston can be linearly moved within the cylinder hole. Therefore, the number of parts can be reduced and the cost can be reduced as compared with the case where the swing arm is used as a cylinder and the cylinder is separately provided.

  FIG. 1 is a schematic diagram showing a rear wheel suspension device, and FIG. 2 is a schematic diagram showing a fully extended state of the rear wheel suspension device.

FIG. 1 shows a swing arm type rear wheel suspension device 10 for a motorcycle.
The suspension device 10 is attached to a pivot shaft 12 provided on a vehicle body side frame 11 (or a power unit including an engine and a transmission attached to the vehicle body side frame 11) so that a front end portion of a swing arm 14 is swingably mounted. A rear wheel 13 is rotatably supported at the rear end of the arm 14, and a hydraulic shock absorber 20 is interposed between the vehicle body side frame 11 and the swing arm 14. In this specification, the front refers to the forward direction side of the vehicle, and the rear refers to the reverse direction side.

  The hydraulic shock absorber 20, the inside of the intermediate part sandwiched between the front end part and the rear end part of the swing arm 14, specifically, the vertical direction in the cross member connecting the both side arms of the swing arm 14 (in this specification, Is a vertically upper side, and the lower is a vertically lower side), and a lower end portion of the cylinder hole 21 is opened.

  The hydraulic shock absorber 20 liquid-tightly penetrates the guide member 22 provided at the opening of the cylinder hole 21, inserts the piston rod 23 into the cylinder hole 21, and includes the piston 24 provided at the insertion end of the piston rod 23. Liquid-tight sliding contact is made in the cylinder hole 21. The piston 24 defines two upper and lower oil chambers 25A and 24B in the cylinder hole 21, and accommodates hydraulic oil in both the oil chambers 25A and 25B.

  The hydraulic shock absorber 20 includes an upper end portion (first end portion) of the first link 31 (an intermediate portion sandwiched between the rear end portion supporting the rear wheel 13 and the cylinder hole 21 in the front-rear direction of the swing arm 14). The shaft 31A) is pivotally mounted so as to be swingable. Further, the front end portion (the shaft 32A) of the second link 32 is pivotally attached to the lower position of the pivot shaft 12 in the vehicle body side frame 11.

  The hydraulic shock absorber 20 pivotally attaches the rear end portion of the third link 33 to the lower end portion (shaft 31 </ b> B) of the first link 31 and swings the second link to the intermediate portion of the third link 33. The rear end portion (shaft 32B) of the link 32 is pivotally attached, and the end portion protruding from the cylinder hole 21 of the piston rod 23 is pivotably attached to the front end portion (shaft 33A) of the third link 33. . The third link 33 always has a forward inclined shape in which the front end portion is positioned in front of and above the rear end portion.

  The hydraulic shock absorber 20 has a front end portion (shaft 33A) of the third link 33, and a lower end portion (shaft 31B) of the first link 31 and a front end portion (shaft 32A) of the second link 32 when fully extended. It arrange | positions so that it may be located above the straight line c to connect. A straight line connecting the upper end (axis 31A) of the first link 31 and the front end (axis 32A) of the second link 32 is a, and the upper end (axis 31A) and lower end (first of the first link 31) 3 is the straight line connecting the rear ends of the links 33 (axis 31B).

  The hydraulic shock absorber 20 has a suspension spring (not shown) interposed between the swing arm 14 and the piston rod 23, and relieves the impact received by the vehicle from the road surface due to the compression displacement of the suspension spring.

  The hydraulic shock absorber 20 includes a damping force generator (not shown) that suppresses expansion and contraction vibration of the suspension spring. The damping force generator includes a piston 24 with a pressure side channel and an extension side channel connecting the upper and lower oil chambers 25A and 25B, a pressure side plate valve in the pressure side channel, and an extension side plate valve in the extension side channel. Composed. The hydraulic shock absorber 20 includes an oil reservoir chamber (not shown) that communicates with the oil chambers 25 </ b> A and 25 </ b> B and compensates the hydraulic oil corresponding to the volume of the piston rod 23 entering / withdrawing into the cylinder hole 21 in the swing arm 14.

The operation of the suspension device 10 will be described.
(1) When the motorcycle gets over the convex portion of the road surface and the rear wheel 13 moves upward with respect to the vehicle body side frame 11, the swing arm 14 swings upward from the boarding neutral position, and the hydraulic shock absorber 20 moves to the compression stroke. (FIG. 1). The hydraulic shock absorber 20 reduces the impact that the vehicle receives from the road surface by compressing the suspension spring. At the same time, the hydraulic shock absorber 20 moves the piston rod 23 into the cylinder hole 21 and moves the oil in the upper oil chamber 25A from the pressure side flow path of the damping force generator to the lower oil chamber 25B, and is moved by the pressure side plate valve. Get the compression side damping force.

  (2) When the rear wheel 13 moves downward with respect to the vehicle body side frame 11 and the swing arm 14 swings downward from the boarding neutral position, the hydraulic shock absorber 20 goes into an extension stroke (FIG. 2). The hydraulic shock absorber 20 moves the piston rod 23 out of the cylinder hole 21 and moves the oil in the lower oil chamber 25B from the expansion side flow path 42 of the damping force generation device to the upper oil chamber 25A. Get the extension damping force.

  The expansion and contraction vibration of the suspension spring is controlled by the damping force on the compression side and the expansion side in the above (1) and (2).

  When the swing arm 14 of the suspension device 10 swings up and down as described in (1) and (2) above, the first link 31, the second link 32, the third link 33 and the piston rod 23 are as follows. To work.

  (1) The swing arm 14 swings up and down around the pivot shaft 12. When the swing arm 14 swings upward, the upper end portion (the shaft 31 </ b> A) of the first link 31 also swings as indicated by a line I about the pivot shaft 12.

  (2) The rear end portion (shaft 32B) of the second link 32 swings as shown by line II around the front end portion (shaft 32A).

  (3) The piston rod 23 is set so as to move on the central axis III of the cylinder hole 21.

  (4) The rear end portion (shaft 31B) and the front end portion (shaft 33A) of the third link 33 swing around the intermediate shaft 32B.

  (5) When the swing arm 14 swings upward, the length of the straight line a connecting the shaft 31A and the shaft 32A becomes longer. On the other hand, the rear end portion (shaft 32B) of the second link 32 swings upward so as to absorb the length of the straight line a. The front end portion (shaft 33A) of the third link 33 is located above a straight line c connecting the lower end portion (shaft 31B) of the first link 31 and the front end portion (shaft 32A) of the second link 32 when fully extended. When the rear end portion (shaft 32B) of the second link 32 swings upward as described above by setting it so as to be positioned, the front end portion (shaft 33A) of the third link 33 is also always in the cylinder hole. It moves linearly upward along the central axis of 21.

  (6) The first link 31 and the third link 33 are displaced according to the upward linear movement of the front end portion (the shaft 33A) of the third link 33.

According to the present embodiment, the following operational effects can be obtained.
The upper end portion of the first link 31 is pivotably attached to the middle portion of the swing arm 14, and the front end portion of the second link 32 is swingable at a lower position of the pivot shaft 12 in the vehicle body side frame 11. The rear end portion of the third link 33 is pivotably attached to the lower end portion of the first link 31, and the rear end of the second link 32 is attached to the intermediate portion of the third link 33. The end portion protruding from the cylinder hole 21 of the piston rod 23 is pivotably attached to the front end portion of the third link 33, and the front end portion of the third link 33 is extended to the maximum extent. Sometimes, the first link 31 and the second link 32 are arranged so as to be positioned above a straight line c connecting the lower end portion of the first link 31 and the front end portion of the second link 32. Therefore, even if the cylinder hole 21 cannot swing with respect to the swing arm 14, the piston rod 23 moves on the central axis of the cylinder hole 21, and the piston rod 23 and the piston 24 can move linearly within the cylinder hole 21. Therefore, the number of parts can be reduced and the cost can be reduced as compared with the case where the swing arm 14 is used as a cylinder and a cylinder is provided separately.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Included in the invention.

FIG. 1 is a schematic view showing a rear wheel suspension device. FIG. 2 is a schematic diagram showing the most extended state of the rear wheel suspension device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rear wheel suspension apparatus 11 Vehicle body side frame 12 Pivot shaft 13 Rear wheel 14 Swing arm 21 Cylinder hole 22 Guide member 23 Piston rod 24 Piston 25A, 25B Oil chamber 31 First link 32 Second link 33 Third link

Claims (1)

In a rear wheel suspension device such as a motorcycle in which the front end of the swing arm is swingably attached to a pivot shaft provided on the vehicle body side frame, and the rear wheel is rotatably supported on the rear end of the swing arm.
In the vertical direction in the swing arm, a cylinder hole having a lower end opened is formed,
The piston rod is inserted into the cylinder hole through the guide member provided at the opening of the cylinder hole, and the piston provided at the insertion end of the piston rod is brought into sliding contact with the cylinder hole. Provided with an oil chamber defined by the piston,
The upper end of the first link is pivotally attached to the middle part of the swing arm, and the front end of the second link is pivotally attached to the lower position of the pivot shaft in the vehicle body side frame. And
A rear end portion of the third link is pivotally attached to a lower end portion of the first link, and a rear end portion of the second link is pivotally attached to an intermediate portion of the third link. , An end projecting from the cylinder hole of the piston rod is pivotally attached to the front end of the third link,
The automatic operation is characterized in that the front end portion of the third link is disposed above the straight line connecting the lower end portion of the first link and the front end portion of the second link at the maximum extension. Rear wheel suspension for motorcycles.

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