JPH11198889A - Swing arm of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swing arm of mono-shock type whereby a compact vehicle body is achieved while a good rigidity is maintained in a supporting part of a shock absorber by using the over-space of the swing arm effectively. SOLUTION: A swing arm 33 is equipped with a forefront cylindrical shaft part 51 and a pair of a left and a right arm parts 52 extending backward from the cylindrical shaft part 51, and the rear wheel axle is supported at the tail of the arm part 52 and the cylindrical shaft part 51 is mounted on the body frame rotatably and resilient support is established by a single shock absorber 22. The coupling position of the shock absorber 22 with swing arm 33 is set a constant level higher than the swing arm 33 by the use of an upward protruding mounting table 58, and the front surface 58a of the mounting table is made a slope inclined backward. This allows installation in a forward prostrated attitude without interference of the shock absorber 22 with the mounting table 58, etc., and the swing arm 33 can be embodied without resulting in a long size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing arm of a vehicle such as a motorcycle, which comprises a front end pivot shaft, and a pair of left and right arms extending rearward from the front end pivot shaft.
The present invention relates to a swing arm in which a rear wheel axle is supported at a rear end of an arm portion, a front end rotation shaft portion is rotatably attached to a vehicle body frame, and is elastically supported by a single shock absorber so as to be vertically swingable.

[0002]

2. Description of the Related Art As a rear suspension for elastically supporting a swing arm of this type, a so-called two-shock type in which a pair of left and right shock absorbers are arranged at the rear portion is shown in FIG.
As described above, there is a so-called mono-shock type in which one shock absorber 80 is disposed at the front portion in the center of the vehicle width.

[0003] In the two-shock type, a pair of left and right shock absorbers is connected to a rear portion of a swing arm, and extends upward to be connected to a rear pipe.

[0004] In the monoshock type shown in FIG. 8, a downward mounting bracket 82 is formed below a front portion of a swing arm 81 in which a front end rotating portion 89 is supported by a comp 85. A single shock absorber 80 is disposed in a substantially upright posture, the lower end of the shock absorber 80 extends to the lower side of the swing arm 81, and is pivotally connected to the mounting bracket 82 via amplification links 87 and 88. ing. Thus, the shock absorber 80
The lower connecting portion of the lower arm is lowered to a position below the swing arm 81, and the amplification is performed by the amplification links 87 and 88.
This is because the mounting bracket 82 is located closer to the rotating part 89 of the swing arm 81 and has a smaller swing range than the two-shock type.
By transmitting to zero, the required amount of expansion and contraction stroke of the shock absorber 80 is secured, and the sensitivity of shock absorption is maintained. By the way, although not shown, there is also a structure in which the lower end of the shock absorber 80 is directly connected to the mounting bracket 82 without the intermediary of a link mechanism for amplification. Become. The prior art document includes Japanese Utility Model Laid-Open No. 6-201825.

[0005]

In the two-shock type,
Because the left and right shock absorbers project left and right,
The vehicle width increases. Also, the use of two shock absorbers increases the number of parts and the weight.

On the other hand, in the mono-shock type shown in FIG. 8, the vehicle width can be made compact and the number of parts can be reduced to reduce the weight. However, the shock absorber 80 itself has to be disposed between the turning part 89 and the rear wheel 84 to a position below the swing arm 81. That is, since the shock absorber 80 itself is disposed between the front end rotating portion 89 and the rear wheel 84, a large space must be secured in front of the rear wheel 84, and the swing arm becomes longer.

A mounting bracket 96 is provided on the rear pipes 91 and 92 supporting the seat via a seat mounting bracket 90 or the like via a cross member or the like, and the upper end of the shock absorber 80 in an upright posture is provided on the mounting bracket 96. However, a large bending load is applied to the rear pipes 91 and 92 so as to protrude upward.
Thick and strong ones must be used as 1,92, which leads to an increase in weight.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to make it possible to efficiently use a space between a rear wheel and a front end rotating portion of a swing arm as a space for arranging a shock absorber and a rear wheel. The aim is to shorten the front-rear length of the car and keep the overall body compact.

[0009]

In order to achieve the above object, according to the present invention, a front end rotation shaft, a pair of left and right arms extending rearward from the front end rotation shaft are provided. A vehicle that supports a rear wheel axle at a rear end of an arm portion, a front end rotation shaft is rotatably attached to a vehicle body frame, and is elastically supported by a single shock absorber so as to be vertically swingable. In the swing arm, on the cross member that connects the left and right arm portions at a position on the front side of the rear wheel, a mounting base having a front inclined rear surface is provided in an upwardly projecting shape, and a shock absorber provided at an upper end of the mounting base is provided. A rear end portion of the shock absorber extending forward is rotatably connected to the mounting portion.

According to a second aspect of the present invention, in the swing arm of the vehicle according to the first aspect, the mounting base is formed in a quadrangular pyramid shape in which the left and right width and the front and rear width become narrower as going upward. I have.

[0011]

FIG. 1 is a left side view of an entire step-through type motorcycle to which the present invention is applied, in which a fuel tank 2 is disposed below a seat 1, and a fuel tank 2 is provided in front of and below the seat 1. Has a space S1 penetrating left and right as a step-through type.

The frame F includes a head pipe 5, a main pipe 6 extending downward from the head pipe 5 and inclined backward, and a generally J-shaped right and left welded to a rear portion of the main pipe 6. A pair of middle pipes (middle members)
, A pair of left and right upper rear pipes 8 welded near the front ends of the left and right middle pipes 7, and a pair of left and right lower rear pipes 9 welded to the rear ends of the left and right middle pipes 7. The handle device 3 is attached to the head pipe 5. The left and right sides of the frame F are covered with a cover 10 except for the rear half of the middle pipe 7.

The engine 13 is a single-cylinder engine and is inclined forward to an angle close to a horizontal attitude.
12 and located below the main pipe 6 and the middle pipe 7. A change pedal 16 and an output sprocket gear 17 are disposed on the left side of the crankcase 14 of the engine 13. A drive chain 20 is wound around the output sprocket gear 17 and a driven sprocket gear 18 of the rear wheel 12. ing. A step shaft 1 extending left and right is provided at the rear of the lower surface of the crankcase 14.
9 is fixed, and steps 23 for the driver are provided at both left and right ends of the step shaft 19. Exhaust pipe 21
Extends below the engine 13 to the right of the rear wheel 12, and has a muffler 21a connected to the rear end.

An air cleaner 2 is provided above and in front of the engine 13.
4, a battery 15 and a single shock absorber 2 for a rear suspension are provided below the fuel tank 2.
2 are arranged.

In FIG. 3 showing a left side view of the frame alone, a round pipe having a large diameter and a circular cross section is used as the main pipe 6, and the middle pipe 7 and the rear pipes 8 and 9 also have a circular cross section. Round pipes are used. A mounting bracket 25 for the engine is welded to the rear end of the lower surface of the lower surface of the main frame 6, and a mounting bracket 26 for the air cleaner is welded on the way. A mounting bracket 27 for mounting is welded.

The J-shaped middle pipe 7 has a front half (upper half) 7a linearly extending substantially rearward and downward along a rear extension line of the main pipe 6, and a rear half 7b curved downward. The front edge is welded to both sides of the main pipe 6 at a position slightly forward from the rear end of the main pipe 6. A vertical rib / mounting plate 29 is welded to the middle pipe 7 along its length direction.
Projecting downward in the front half 7a of the middle pipe and projecting forward in the rear half 7b, the total length of the rib / mounting plate 29 extends from the position P1 corresponding to the rear edge of the main pipe 6 to the rear half 7b. To the vicinity of the lower end. The mounting plate 29 has a swing arm mounting hole 31 formed in the middle part of the rear half 7b in the vertical direction, and the engine mounting hole 3 formed in the middle part of the front half 7a in the front and rear length.
2 are formed. The lower ends of the left and right middle pipes 7 are welded together by a cross pipe 35 as shown in FIG. 6, and the cross pipe 35 has a mounting bracket 36 for an engine and a mounting boss 37 for a center stand.
Is welded. 3, the front and rear ends of the upper surface of the crankcase 14 are mounted and supported by the mounting bracket 25 of the main pipe 6 and the mounting holes 32 of the mounting plate 29 with through bolts or the like. It is mounted and supported on the lower end mounting bracket 36 of the portion 7b using a through bolt or the like.

The front end of the upper rear pipe 8 is welded to the vicinity of the front end of the middle pipe 7, and the position is substantially corresponding to the position P1 of the rear end of the main pipe, and gradually rises from the position P1. It extends rearward in an inclined position. On the upper surface side of the upper rear pipe 8, mounting brackets 39 and 40 for the fuel tank, a mounting pipe 41 for the seat, and a mounting bracket 42 for the seat are provided in order from the front side. The front mounting bracket 39 is welded to a cross pipe 45 that connects the left and right upper rear pipes 8. The fuel tank 2 is mounted on front and rear fuel tank mounting brackets 39 and 40. The rear mounting bracket 40 supports a flange portion 2 a formed by upper and lower mating surfaces of the fuel tank 2. The tandem seat 1 has a mounting pipe 41 and a mounting bracket 42 in the rear half.
The front half is supported on the fuel tank 2 via a damper (not shown) and the like.

The front end of the lower rear pipe 9 is located lower than the front end of the upper rear pipe 8 and is welded to the upper part of the middle pipe rear half 7b. It extends rearward and upward at a large inclination angle, and its rear end is welded to the rear part of the upper rear pipe 8, which is an intermediate portion between the seat mounting bracket 42 and the mounting pipe 41. The inclination of the lower rear pipe 9 with respect to the horizontal plane is set to, for example, about 45 °, and both rear pipes 8 and 9 are inclined.
The angle θ2 between them is widened to about 30 °, so that the triangular framework formed by the rear pipes 8, 9 and the middle pipe 7 has high strength. A mounting bracket 47 for a brake component (for example, a master cylinder) is welded to the right lower rear pipe 9, and a passenger step mounting bracket 48 is welded to the left and right lower rear brackets 9. In addition, each pipe is provided with a mounting bracket or the like for a cover, though not denoted by a reference numeral.

FIG. 2 is a plan view of the frame alone. The left and right middle pipes 7 are arranged so as to open in a V-shape when viewed from above, and the left and right upper rear pipes 8 are arranged.
Has a shape in which the front end is slightly opened in a V-shape (C-shape), but mostly extends rearward in parallel to the left and right, and a tail plate 49 is fixed to the rear end edge by bolts or the like. .
The left and right lower rear pipes 9 are arranged so that the left and right intervals gradually become narrower toward the rear.

FIG. 4 is a plan view showing the structure of the swing arm 33 and the rear suspension 30. The rear suspension 30 is a mono-shock type having one shock absorber 22. The swing arm 33 includes a cylindrical shaft portion 51 at a front end portion, and a pair of left and right arm portions 52 welded to the cylindrical shaft portion 51 and extending rearward. A rear axle 54 is provided at a rear end portion of the arm portion 52. The cylindrical shaft portion 51 is supported between the left and right rib / mounting plates 29, and the bolt-type pivot shaft 55 inserted through the mounting holes 31 (FIG. 3) for the swing arms of the mounting plates 29 via a bearing. It is rotatably supported.
At a position slightly behind the cylindrical shaft portion 51, two cross members 56 and 57 for connecting the left and right arm portions 52 are welded to the arm portion 52, and approximately at the center of the upper surfaces of the cross members 56 and 57. A shock absorber mounting base 58 having a quadrangular pyramid shape projecting upward at a predetermined height is welded. In addition, between the rear cross member 57 and the left and right arm portions 52,
A gusset 59 for reinforcement is welded to each.

The shock absorber 22 includes a cylinder portion 60 and a rod 61 which are slidably fitted in the front-rear direction.
And a spring 62 contracted between the cylinder part 60 and the rod 61. The rear end of the spring 62 is attached to a U-shaped mounting bracket 63 welded to the upper end of a mounting base 58 on the swing arm. The front end is rotatably supported via a bolt 65 on the mounting bracket 27 at the rear end of the main pipe.
By welding (or attaching) a cylindrical spacer 66 to the right inner surface of the front mounting bracket 27, the shock absorber 22 is slightly deviated to the left from the vehicle width center line O1. A space for arranging the battery 15 on the right side is ensured, and the right and left weight balance with the heavy battery 15 is balanced.

FIG. 5 is a sectional view taken along the line V--V in FIG. 4, in which the shock absorber 22 passes a predetermined height above the cylindrical shaft portion 51 of the swing arm 33 to the front, and the middle pipe 7
It is arranged in a forwardly inclined posture substantially inclined along a. Also, when viewed as a whole vehicle body, the shock absorber 22
Is disposed in a front-rear posture at a substantially central portion of the front-rear width of the vehicle body. The front mounting bracket 27 is welded to an inclined surface 6 a formed on the rear end edge of the main pipe 6, and a bolt insertion hole 27 a of the mounting bracket 27 is provided.
Is located at the bottom of a V-shaped open space S1 formed by the middle pipe 7 and the upper rear pipe 8, and allows the bolt 65 to be inserted and removed from the side of the frame. By providing the mounting bracket 27 at the front end of the shock absorber 22 at the V-shaped bottom formed by the middle pipe 7 and the upper rear pipe 8 in the step-through space S1 as described above, the step-through type vehicle is provided. While securing a sufficiently wide step-through space S1 of
The bottom can be effectively used as a space for mounting the shock absorber, and the shock absorber 2
The mounting workability from the side of 2 can also be secured.

The mounting base 58 in the shape of a quadrangular pyramid has a front surface 58a formed in a rearwardly inclined position and a rear surface 58b formed in a substantially vertical position. A space that allows the rear lower end of the rear wheel 22 to be accommodated without interfering with the mounting base 58 is secured, and a space that allows the rear wheel 12 to be arranged close to the rear is secured. Of the two cross members 56 and 57, the rear cross member 57 is a rectangular pipe having a rectangular cross section, and the front cross member 56 is a member having a U-shaped cross section. In response to the shock absorber 22 being slightly deviated leftward as described above, the upper end mounting bracket 63 of the mounting base 58 is also deviated leftward from the vehicle width center line O1 as shown in FIG. Also, due to the unevenness as described above, the right side surface of the mounting base 58 has a gentler inclined surface than the left side surface, and it is easy to arrange the battery 15 on the right side.

When the swing arm 33 swings up and down,
The shock absorber 22 expands and contracts in a direction substantially along the upper half portion 7a of the middle pipe at a position above the cylindrical shaft portion 51 by a predetermined height, and absorbs shocks and the like. In addition, the shock absorber 22
Is supported by the rear end of the large-diameter main pipe 6,
In addition, the main pipe 6 can receive the load applied to the swing arm 33 by being inclined at substantially the same angle as the main pipe 6.

The mounting base 58 has a quadrangular pyramid shape in which both the left-right width and the front-rear width decrease as it goes upward, so that high rigidity can be maintained and no extra space is occupied.

[0026]

[Other Embodiments] (1) The swing arm according to the present invention can be applied to a four-wheel buggy and the like.

(2) The present invention can of course be applied to vehicles other than the step-through type vehicle.

[0028]

As described above, according to the present invention, (1) the shock absorber 22 and the swing arm 33 are rotated at a position higher than the swing arm 33 by a fixed height by the mounting base 58 having the front surface 58a inclined backward. Movably connected,
Since the shock absorber 22 is extended forward, it is possible to connect the shock absorber 22 to the mounting table 58 in a forwardly inclined posture without interfering with the mounting table 58 while maintaining the rigidity of the mounting table 58, and , The shock absorber 22 is in the forward falling posture, so that the mounting
8, a space on the rear side can be ensured, and the tire of the rear wheel 12 can be brought as close as possible to the mount 58, so that the length of the swing arm 33 can be kept compact. In other words, the space above the swing arm 33 and the space before and after the mounting table 58 can be used without waste for the rear end portion of the shock absorber 22 and the tires of the rear wheels 12 in the forwardly inclined posture. A reduction in the length of the arm 33 and a reduction in the overall size of the vehicle body can be achieved.

(2) Since the rear end of the shock absorber 22 is supported at a position higher than the swing arm 33 by a certain height, the work of attaching and detaching the rear end of the shock absorber 22 from the side of the vehicle body can be easily performed.

(3) Since the mounting base 58 has a quadrangular pyramid shape and the mounting bracket (mounting portion) 63 is provided at the upper end thereof, the rigidity of the mounting base 58 is ensured. Also, the space for arranging the shock absorber and the space for arranging the rear wheel as described above can be secured.

[Brief description of the drawings]

FIG. 1 is a left side view of a motorcycle to which the present invention is applied.

FIG. 2 is a plan view of a single frame of the motorcycle of FIG. 1;

FIG. 3 is a view as viewed in the direction of the arrow III in FIG. 2 (left side view).

FIG. 4 is an enlarged plan view of a swing arm and a rear suspension.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is an enlarged partial view taken along the arrow VI in FIG. 3;

FIG. 7 is a sectional view taken along the line VII-VII of the mount of FIG. 5;

FIG. 8 is a left side view of a conventional swing arm.

[Explanation of symbols]

 F Body frame 12 Rear wheel 22 Shock absorber 33 Swing arm 51 Cylindrical shaft part (rotating shaft part) 52 Arm part 56, 57 Cross member 58 Mounting base 63 Take bracket (Mounting part)

Claims (2)

[Claims] A front end pivot shaft portion; a pair of left and right arms extending rearward from the front end pivot shaft portion; a rear wheel axle supported at a rear end portion of the arm portion; A cross member that connects the left and right arm parts at a position on the front side of the rear wheel in a swing arm of a vehicle in which the shaft is rotatably mounted on the body frame and is elastically supported by a single shock absorber so that it can swing vertically. On the upper side, a mounting base with a rear inclined surface is provided so as to protrude upward, and the rear end of the shock absorber extending forward is rotatably connected to the mounting part for shock absorber provided at the upper end of the mounting base. A swing arm for a vehicle, comprising: 2. The swing arm for a vehicle according to claim 1, wherein the mounting base is formed in a quadrangular pyramid shape in which a front-rear width and a left-right width become narrower as going upward.