JP4673713B2 - Vehicle swing arm - Google Patents

Description

  The present invention relates to an improvement of a swing arm of a vehicle.

As a conventional vehicle swing arm, there is known a swing arm that is attached to a front portion of a vehicle body frame so as to freely swing up and down and extends forward to support a front wheel at a front end (see, for example, Patent Document 1).
JP 2000-219182 A

  As shown in FIG. 2 of Patent Document 1, a stay 31 is provided at the lower front portion of the vehicle body frame 2, and the rear end of an inverted U-shaped swing arm 33 is swingable on the stay 31 via a front pivot shaft 32. It is described that an axle holder block 35 is attached to the front end of the swing arm 33 via a king pin 34 so as to swing left and right, and the front wheel 3 is rotatably attached to the axle holder block 35 via an axle 36. Yes.

  In FIG. 2, a head pipe 52 is provided at the upper front part of the body frame 2, a steering stem 53 is rotatably inserted into the head pipe 52, and a bar handle 54 is attached to the upper part of the steering stem 53. It is described that the rear end of the steering arm 55 is attached to the lower portion of the steering stem 53 and the front end of the steering arm 55 is connected to the axle holder block 35 via the link mechanism 56.

Since the swing arm 33 has an inverted U shape when viewed from the side, the overall length is large. For example, when a large side force acts on the front wheel 3, the swing arm 33 is likely to be bent or twisted. The front end of the front wheel 3, that is, the toe may swing left and right due to the influence of bending and twisting. Further, when the bar handle 54 is cut to the left and right, the side force acts on the front wheel 3, so the same thing as described above may occur.
An object of the present invention is to suppress left-right deflection of the front wheels, that is, toe change of the front wheels.

According to the first aspect of the present invention, a swing arm is extended from the lower part of the front part of the vehicle body frame so as to freely swing up and down, and an axle holder block that supports the axle for the front wheels is attached to the front end of the swing arm so as to freely swing left and right The steering stem is rotatably attached to the head pipe provided at the upper part of the front, a steering arm extending forward is attached to the steering stem, and the tip of the steering arm is connected to the axle holder block from one side of the front wheel, In a vehicle in which the front wheel is suspended and steerable, the swing arm is a member provided with a hollow portion, and the thickness of the swing arm on the side closer to the side farther from the front wheel is increased. And a base part attached to the front wheel through the shaft part. An arm part extending, the base part is coupled along the outer surface of the arm part and includes an extension part extending to the lower surface of the arm part, the cross section of the arm part is elliptical, the extension part is It is formed along the outer surface shape of the arm part, and extends to the center of the lower surface of the arm part .

As an action, by increasing the thickness of the side of the swing arm closer to the side farther from the front wheel, when the side force acts on the tip of the swing arm, the thickness of the side closer to the front of the swing arm is reduced. The deflection and twist of the swing arm are effectively reduced by the enlarged portion.
Moreover, the extension part with which a base part is equipped is couple | bonded along the outer surface of an arm part, and the rigidity of the coupling | bond part of a base part and an arm part increases because it extends to the lower surface of an arm part.
Furthermore, when the extension portion and the arm portion are combined, for example, when welding, the extension portion and the arm portion are easily aligned. Further, if the elliptical long axis is in the horizontal direction, the bending rigidity of the arm portion with respect to the side force is increased.

In the invention according to claim 1, since the swing arm is a member provided with a hollow portion, and the wall thickness on the side closer to the side farther from the front wheel of the swing arm is increased, the swing arm is effectively bent and twisted. It is possible to reduce the toe change of the front wheels even when the front wheels are subjected to side forces during turning or steering of the vehicle.
In the present invention, the swing arm includes a base portion attached to the body frame via a shaft portion, and an arm portion extending from the base portion toward the front wheel, and is coupled to the base portion along the outer surface of the arm portion. In addition, since the extending portion extending to the lower surface of the arm portion is provided, the rigidity of the connecting portion between the base portion and the arm portion can be improved by the extending portion, and the toe change of the front wheel can be further suppressed.
Furthermore, in the present invention, the cross-section of the arm portion is elliptical, and the extension portion is formed along the outer surface shape of the arm portion, and is extended to the center of the lower surface of the arm portion. For example, welding work can be facilitated. Further, by orienting the long axis of the ellipse in the horizontal direction, the bending rigidity of the arm portion can be increased, and the toe change of the front wheel can be further suppressed.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of a vehicle equipped with a swing arm according to the present invention. A scooter type motorcycle 10 as a vehicle has a frame-like body frame 2 disposed at a lower center portion, A front suspension 4 for suspending the front wheel 3 and a steering device 5 for steering the front wheel 3 are attached, a swing type power unit 6 is attached to the rear part of the body frame 2, and a rear wheel 7 is attached to the rear end of the power unit 6. The rear cushion unit 8 is attached to the rear portion of the vehicle body 6 and the rear portion of the vehicle body frame 2, and the seat 9 is attached to the rear upper portion of the vehicle body frame 2. The power unit 6 includes an engine 6a.

The scooter type motorcycle 10 includes a front fender 10a, a front cover 12, a handle cover 13, a leg shield 14 that covers a driver's legs, a step floor 15 for a driver's footrest, an under cover 16, and a center. A cover 17, a rear cover 18, and a rear fender 19 are provided.
The step floor 15 is a resin product formed integrally with the leg shield 14 and is mounted on the intermediate portion 2M of the vehicle body frame 2 and screwed.

  The vehicle body frame 2 has a dividing line W at an intermediate portion 2M thereof, that is, at a position below the step floor 15, and a rear frame 2R is detachably coupled to the front frame 2F at the position of the dividing line W. is there.

  Further, the vehicle body frame 2 has a main stand 93 and a side stand 95 attached to the lower rear part. In addition, 21 is a mirror, 22 is a headlamp, 23 is a winker, 24 is a radiator, 25 is a carrier, 26 is a tail lamp, 27 is an exhaust pipe, and 28 is a muffler.

  FIG. 2 is a side view showing the vehicle body frame and the front and rear wheel suspension structure of the vehicle according to the present invention. The front suspension 4 extends a stay 31 forward from the front portion of the vehicle body frame 2, and a front pivot is attached to the stay 31. A rear end of a swing arm 33 having a substantially inverted U-shape when viewed from the side is attached to the shaft 32 so that it can swing up and down, and an axle holder block 35 is attached to the front end of the swing arm 33 via a king pin 34 so as to swing left and right. A front wheel 3 is rotatably attached to a wheel 35 via an axle 36. That is, the swing arm 33 is extended forward from the front portion of the vehicle body frame 2, and the front wheel 3 is cantilevered by the swing arm 33.

  In addition, the front suspension 4 is provided with a resin spring 43 that reduces the swing direction shock of the swing arm 33, that is, a shock from the road surface, and a front damper 47 that attenuates the swing direction vibration of the swing arm 33. It is a thing.

Specifically, a resin spring 43 that reduces the impact in the swing direction of the swing arm 33 is interposed between the body frame 2 and the swing arm 33, and the swing arm 33 is supported by the front damper 47 at the front portion of the body frame 2. It is a thing.
The resin spring 43 is a buffer member made of a resin block having elasticity so as to perform a spring action.

  One end of the front damper 47 is attached to the right side (back side in the figure) of the base of the head pipe post 51 described later by a support shaft 48, and the other end of the front damper 47 is connected to the left side of the top of the swing arm 33. Is attached by a support shaft 49. Note that one end of the front damper 47 may be directly attached to the vehicle body frame 2.

  The steering device 5 extends a head pipe post 51 obliquely upward and forward from the upper front portion of the body frame 2, forms a head pipe 52 at the tip of the head pipe post 51, and the steering stem 53 is rotatably inserted into the head pipe 52. The bar handle 54 is attached to the upper end of the steering stem 53, the rear end of the steering arm 55 is attached to the lower end of the steering stem 53, and the axle holder block 35 is attached to the front end of the steering arm 55 via the link mechanism 56. The front wheel 3 can be steered by connecting the knuckle 35a. Reference numeral 57 denotes a grip.

  As described above, the swing arm type front suspension 4 is adopted, and the load from the front wheel 3 is received by the highly rigid body frame 2 via the swing arm 33 and the front pivot shaft 32. The load can be reliably and effectively received by the body frame 2. For this reason, a large load is unlikely to act on the head pipe post 51.

  As for the support structure of the power unit 6, the rear frame 61 extends rearward and obliquely upward from the rear end of the vehicle body frame 2, the stay 62 is bolted to the rear frame 61, and the power unit 6 is vertically moved to the stay 62 by the rear pivot shaft 63. The power unit 6 is suspended from the rear frame 61 by the rear cushion unit 8 so as to be swingable.

  The rear cushion unit 8 is located on the left side of the rear wheel 7 and has one end attached to the mounting boss 65 of the rear frame 61 with a support shaft 66 and the other end attached to the stay 6b of the power unit 6 with a support shaft 67. It is.

  FIG. 3 is a plan view showing the suspension structure of the vehicle body frame and the front and rear wheels of the vehicle according to the present invention. The swing arm 33 is bent forward from the front portion of the vehicle body frame 2 to the right so as to bypass the front wheel 3. The steering arm 55 is extended from the head pipe 52 (specifically, the lower end of the steering stem 53 (see FIG. 2)) on the vehicle body center line CL to the front while curving to the right so as to bypass the front wheel 3. The power unit 6 is extended from the rear part of the frame 2 to the rear, and the rear wheel 7 is cantilevered by the power unit 6.

  Since the swing arm 33 is offset from the vehicle body center line CL to the right and the power unit 6 is offset from the vehicle body center line CL to the left, the left and right weight balance of the scooter type motorcycle 10 can be improved.

  FIG. 4 is an exploded perspective view of the front suspension and the steering device according to the present invention, and a swing arm is provided at the pivot hole 31a, 31a of the stay 31, 31 provided on the left and right of the lower front portion of the vehicle body frame 2 by the front pivot shaft 32. 33 support pipes 33a are attached, and the clamping plate 41 is connected to the connecting portions 33c and 33c formed on the plate portion 33b of the swing arm 33 by two sets of upper and lower bolts 42a and nuts 42b (only one nut 42b is shown). The resin spring 43 is sandwiched between the plate portion 33 b and the clamping plate 41, the mounting plate 44 is inserted into the mounting hole 43 a of the resin spring 43, and the left and right ends of the mounting plate 44 are bolted to the mounting bosses 45, 45 of the vehicle body frame 2. 46, 46, one end of the front damper 47 is pivoted to the mounting boss 51a at the base of the head pipe post 51 Mounting 8, the other end portion of the front damper 47 indicates that the attached vertical support shaft 49 in the mounting boss 33d of the top portion of the swing arm 33.

  5 is a view taken in the direction of the arrow 5 in FIG. 4. The swing arm 33 includes a base portion 33e and a pipe-shaped arm portion 33f coupled to the base portion 33e by welding. The base portion 33e is a support pipe. The member 33a and the plate portion 33b are integrally formed, and the connecting portions 33c and 33c are provided on the plate portion 33b.

  FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 5, and the plate portion 33b of the swing arm 33 includes an upper extension portion 33j and a lower extension portion 33k in a coupling portion 33h coupled to the arm portion 33f. Here, the “upper part” of the upper extension part 33j is a part on the body frame 2 (see FIG. 2) side of the plate part 33b, and the “lower part” of the lower extension part 33k is the front wheel 3 ( This is a part on the side). Reference numeral 71 denotes a hollow portion of the arm portion 33f.

  The upper extending portion 33j and the lower extending portion 33k have an outer surface 33m of the arm portion 33f having an elliptical cross section, that is, an inner surface 33r and an inner surface 33s along the upper surface 33n and the lower surface 33p, respectively, and the lower extending portion 33k. Extends to the center of the lower surface 33p of the arm portion 33f.

FIG. 7 is a sectional view showing the shape of the arm portion according to the present invention. The arm portion 33f is a member having an outer surface 33m having an elliptical shape and an inner surface 33u having a substantially elliptical shape.
That is, when the ellipse 80 passing through a part of the inner surface 33u is drawn concentrically with the outer surface 33m, the common major axis of the outer surface 33m and the ellipse 80 is the X axis, and the common minor axis is the Y axis, the first quadrant In 81, the inner surface 33u overlaps the ellipse 80, and in the second quadrant 82, the inner surface 33u gradually enters the inside of the ellipse 80 as the x coordinate increases from the intersection 86 between the positive side of the Y axis and the ellipse 80 to the negative side. At the intersection 87 where the inner surface 33u intersects the negative side of the X axis, the thickness of the arm portion 33f is maximized.

  In the third quadrant 83 and the fourth quadrant 84, the thickness of the arm portion 33f gradually decreases as the x coordinate increases from the intersection 87, and the arm portion 33f at the intersection 89 where the positive side of the X axis and the inner surface 33u intersect. The inner wall 33u overlaps the ellipse 80.

  Here, the major axis of the outer surface 33m is LD1, the minor axis of the outer surface 33m is SD1, the major axis of the ellipse 80 is LD2, the minor axis of the ellipse 80 is SD2, the thickness at the intersection 86 is T1, and the thickness at the intersection 87 is thick. Is T2, the thickness of the intersection 88 (intersection of the negative side of the Y-axis and the inner surface 33u) is T3, and the thickness of the intersection 89 is T4, T2> T3> T1, and T4 is almost equal to T1. equal.

  As described above, the thickness of the portion of the arm portion 33f that is coupled to the plate portion 33b side is made larger than the thickness of the right end portion of the arm portion 33f, thereby effectively increasing the bending rigidity of the arm portion 33f. Furthermore, the rigidity of the joint part between the plate part 33b and the arm part 33f is further increased by joining the thick part of the arm part 33f with the upper extension part 33j and the lower extension part 33k of the plate part 33b. It can raise, and the bending and twist of arm part 33f can be made smaller.

Next, the operation of the swing arm 33 described above will be described.
8A and 8B are operation diagrams showing the operation of the swing arm according to the present invention.
In (a), when a side force F indicated by an arrow acts on the front wheel 3 when the vehicle is traveling (for example, during cornering) or when the front wheel 3 is being steered, a swing is caused through the axle holder block 35 accordingly. A force in the vehicle width direction is applied to the tip of the arm 33. As a result, the swing arm 33 has an inverted U-shape with the arm portion 33f being bent as indicated by the arrow A on the left, starting from the connecting portion 33h between the base portion 33e and the arm portion 33f. Therefore, the arm 33f is also twisted as shown by the arrow B.

  In (b), a horizontal bending force BF and a twisting force TF act on the arm portion 33f. In the present invention, the inner surface 33r, 33s of the coupling portion 33h of the plate portion 33b is made to extend along the outer surface 33m of the arm portion 33f and the lower extension portion 33k is extended to the center of the lower surface 33p of the arm portion 33f. The plate portion 33b and the arm portion 33f can be firmly coupled, and the amount of bending and twisting of the arm portion 33f can be reduced. As a result, the front end 3a of the front wheel 3 (see (a)), that is, the left / right deflection (toe change) of the toe can be suppressed.

  As shown in FIGS. 2 and 6, the present invention firstly extends the swing arm 33 from the lower front portion of the vehicle body frame 2 so as to be swingable up and down, and the front wheel axle is disposed at the front end of the swing arm 33. An axle holder block 35 that supports 36 is mounted so as to be able to swing left and right, a steering stem 53 is rotatably mounted on a head pipe 52 provided at the upper front of the vehicle body frame 2, and a steering arm 55 that extends forward is mounted on the steering stem 53. In the scooter type motorcycle 10 as a vehicle that can suspend and steer the front wheel 3 by connecting the front end of the steering arm 55 to the axle holder block 35 from one side of the front wheel 3, the swing arm 33 is The member provided with the hollow portion 71 is the side far from the front wheel 3 of the swing arm 33. Characterized in that also increase the thickness of the near side.

  Thereby, the bending and twisting of the swing arm 33 can be effectively reduced, and the toe change of the front wheel 3 can be suppressed even when the front wheel 3 receives a side force during turning or steering of the scooter type motorcycle 10. .

As shown in FIGS. 2, 5, and 6, the present invention secondly includes a base portion 33 e attached to the swing arm 33 via a front pivot shaft 32 as a shaft portion on the vehicle body frame 2, and this base. An arm portion 33f extending from the portion 33e toward the front wheel 3, and a lower extension portion 33k coupled to the base portion 33e along the outer surface 33m of the arm portion 33f and extending to the lower surface 33p of the arm portion 33f. It is characterized by.
Thereby, the rigidity of the joint part 33h between the base part 33e and the arm part 33f can be improved by the lower extension part 33k, and the toe change of the front wheel 3 can be further suppressed.

  Thirdly, according to the present invention, the cross section of the arm portion 33f is elliptical, and the lower extension portion 33k is formed along the shape of the outer surface 33m of the arm portion 33f and extends to the center of the lower surface 33p of the arm portion 33f. It was made to be characterized.

  Thereby, it becomes easy to position the lower extension part 33k and the arm part 33f, and for example, welding work can be facilitated. Further, by directing the elliptical long axis in the horizontal direction, the bending rigidity of the arm portion 33f can be increased, and the toe change of the front wheel 3 can be further suppressed.

  In the present invention, the cross section of the arm portion is an ellipse, but the cross section is not limited to this, and may be an oval shape or a shape similar to an oval shape or an oval shape.

  The present invention is suitable for a front wheel swing arm.

It is a side view of a vehicle provided with a swing arm according to the present invention. 1 is a side view showing a vehicle body frame and front and rear wheel suspension structures according to the present invention. It is a top view which shows the vehicle body frame and front-and-rear wheel suspension structure of the vehicle which concern on this invention. 1 is an exploded perspective view of a front suspension and a steering device according to the present invention. FIG. 5 is a view taken in the direction of arrow 5 in FIG. 4. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is sectional drawing which shows the arm part shape which concerns on this invention. It is an action figure which shows the effect | action of the swing arm which concerns on this invention.

Explanation of symbols

  2 ... body frame, 3 ... front wheel, 10 ... vehicle (scooter type motorcycle), 32 ... shaft part (front pivot shaft), 33 ... swing arm, 33e ... base part, 33f ... arm part, 33k ... extension part ( Lower extension part), 33m ... outer surface, 33p ... lower surface, 35 ... axle holder block, 36 ... axle of front wheel, 52 ... head pipe, 53 ... steering stem, 55 ... steering arm, 71 ... hollow part of arm part.

Claims (1)

A swing arm (33) is extended from the front lower part of the vehicle body frame (2) so as to freely swing up and down, and an axle holder block (35) supporting a front wheel axle (36) is mounted on the front end of the swing arm (33). A steering stem (53) is rotatably attached to a head pipe (52) provided at the upper front portion of the vehicle body frame (2) , and a steering arm (55) extending forward is attached to the steering stem (53). In a vehicle that allows the front wheel (3) to be suspended and steered by connecting the front end of the steering arm (55) from one side of the front wheel (3) to the axle holder block (35) ,
The swing arm (33) is a member provided with a hollow portion, and the wall thickness of the swing arm (33) closer to the side farther from the front wheel (3) is increased,
The swing arm (33) includes a base part (33e) attached to the body frame (2) via a shaft part (32), and an arm part extending from the base part (33e) toward the front wheel (3). (33f)
The base portion (33e) includes an extending portion (33k) that is coupled along the outer surface of the arm portion (33f) and extends to the lower surface of the arm portion (33f).
The cross section of the arm portion (33f) is elliptical,
The extension part (33k) is formed along the outer surface shape of the arm part (33f) and extends to the center of the lower surface of the arm part (33f).
A swing arm of a vehicle characterized by that.

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