JPH069991B2 - Chain cover device for motorcycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chain cover device for a chain that is bridged between a sprocket provided on a rear wheel of a motorcycle and an output shaft of a prime mover.

(Prior Art) Conventionally, a chain cover made of a steel plate has a pair of left and right rear arms that support a rear wheel by hanging a bracket downward from a lower end edge of an outer side wall formed in an inverted U-shape in cross section at two positions. It was fastened to one side with screws from the side. When this chain cover moves up and down with the swing of the rear arm, a vertical inertial force due to its own mass is generated at the center of the cross section of the chain cover. Therefore, in the method of mounting the bracket at a position deviated to one side from the center of the inverted U-shaped cross section and fixing it to the rear arm, the chain cover is a cantilever beam,
A moment is added to the base portion of the bracket by the amount obtained by multiplying the inertial force by the deviation from the center of the cross section to the bracket, and repetitive bending stress is generated at the base portion.

Furthermore, in order to reduce the width of the vehicle in the left-right direction to make it compact, when the chain is laid across the sides of the rear fender or the tires of the rear wheels, the chain cover will be closer to them, so there will be no contact. As described above, it is necessary to cut out the inner side walls of the front and rear intermediate portions of the chain cover.

In this case, since the inner side wall is missing, the second moment of area of the cutout portion is small, and the bending stress due to the inertial force is large in the cutout portion.

Therefore, if the material of the chain cover is made of synthetic resin in order to reduce the weight and cost, the strength is much lower than that of steel plate.Therefore, the chain cover is made of synthetic resin and has notches in the front and rear intermediate parts. May not be able to withstand the above bending stress at the base portion or notch portion of the bracket and may be damaged.

On the other hand, in a motorcycle in which the rear arm is supported by one shock absorber in the center of the vehicle body in front of the rear wheel, the rear wheel is easily polluted by the splashed mud and the function of the shock absorber is deteriorated by the stain. Invite.

Therefore, arranging the mudguard plate between the rear wheel and the shock absorber causes an increase in the unsprung load. Therefore, it is desirable that the mudguard plate be made of synthetic resin and be as thin as possible.

However, in this case, the mudguard plate may be easily damaged.

(Object and configuration of the invention) The object of the present invention is to make the chain cover and the mudguard plate made of synthetic resin, and even if they are made thin or have notches, they are not easily damaged and can be firmly attached. It is to provide a chain cover device for a motorcycle.

In order to achieve the above object, the present invention supports a pair of left and right rear arms, which support rear wheels, at the lower rear part of a frame so as to swing freely, and connects a pair of left and right rear arms with a connecting plate. In a motorcycle in which one shock absorber that elastically supports the rear arm is arranged in the center position of the vehicle body between the connecting plate and the base end portion, a chain cover is made of synthetic resin and a reverse U-shaped section is provided. And a notch is formed in the inner side wall of the front and rear intermediate part of the chain cover, and the bracket is hung downward from the lower edge of the outer side wall of the rear part of the chain cover, and this is attached to one rear part of the rear arm. To the upper side of the connecting plate with screws from the lower end edge of the inner side wall of the front part of the chain cover and screwed from above to the outer side wall of the front part of the chain cover. Synthetic resin that is aligned with one outer surface of the rear arm, extends the front portion of the chain cover near the base end portion of the rear arm, and is arranged between the front portion of the rear wheel and the shock absorber. It is characterized in that the mudguard plate made of aluminum is fixed integrally with the inner side wall of the chain cover so as to intersect and stand upright.

(Examples of the Invention) Hereinafter, the present invention will be described with reference to Examples shown in the drawings.

In the figure, at the rear portion of the frame 1, the base end portions of a pair of bifurcated left and right rear arms 2 and 2 are swingably supported by a shaft 3, and the rear wheels 3 are attached to the rear ends of the rear arms 2 and 2. It is pivotally supported. A connecting plate 2A is passed between the rear arms 2 and 2, and a shock absorber 6 is provided at a center position of the vehicle body between the connecting plate 2A and a base end portion. The shock absorber 6 has an upper end protruding from the frame 1. It is attached to the bracket 5 and the rear end to the rear arm 2 via the link 4. The shock absorber 6 is composed of a hydraulic shock absorber 6A and a spring 6B, and the adjustment of the shock absorbing force by the spring is configured such that a sprocket 10 provided on the upper part of the shock absorber 6 can be adjusted by an adjuster 12 via a chain 11. ing.

Further, a chain 9 is bridged between the sprocket 7 provided on the rear wheel 3 and the sprocket 8 provided on the output shaft of the prime mover, and the upper part of the right rear arm 2 covers the movement path of the chain 9. A chain cover 13 made of synthetic resin and having an inverted U-shaped cross section is fixed. This chain cover 13
Notches are provided in the inner side walls of the front-rear intermediate portion of the rear fender 15 and the rear wheels 3 in the lateral vicinity of the tire. And
As shown in FIG. 2, when viewed from above, the outer side wall of the front portion of the chain cover 13 and the outer surface of the right rear arm 2 are aligned with each other, and the front portion of the chain cover 13 is placed near the base end portion of the rear arm 2. It has been extended.

The chain cover 13 hangs a bracket 13B downward from the lower edge of the outer side wall of the rear part of the chain cover 13 and attaches it to the rear arm 2
The rear portion is screwed from the side, and further, the bracket 13A is extended horizontally inward from the lower end edge of the inner side wall of the front portion of the chain cover 13 and screwed to the upper surface of the connecting plate 2A from above.

Since the chain cover 13 moves up and down as the rear arm 2 swings, an inertial force based on its own mass is generated in the up-down direction, and this inertial force acts on the center of the inverted U-shaped cross section.
The brackets 13B and 13A are beams for the chain cover 1
It becomes a fulcrum that supports 3 at both ends, but when viewed from the vehicle front-rear direction, these two fulcrums are on the left and right of the center of the cross section,
The chain cover 13 is a double-supported beam. Further, when viewed from the vehicle left-right direction, the bracket 13B, which is the fulcrum on the rear side, is screwed to the rear arm from the side, so that the inertial force acts to rotate the chain cover 13 about the axis of the screw. Therefore, this fulcrum corresponds to the so-called rotating end of the beam. However, the bracket 13A that serves as a fulcrum on the front side
Corresponds to a so-called fixed end of the beam, which is fixed to the upper surface of the connecting plate 2A from above so as to prevent the rotation.

Therefore, both the front and rear brackets both hang downward from the lower edge of the outer side wall and are offset from the center of the cross section, the chain cover is a cantilevered beam when viewed from the front and rear direction, and both brackets are The strength of the chain cover will be much higher than that of the conventional one in which the fulcrums at both ends of the beam, which are screwed from the side and viewed from the left-right direction, correspond to the rotation ends.

A mudguard 15 is fixed to the frame 1 in front of the upper portion of the rear wheel 3. Also, this mudguard 1
At the lower end of 5, a thin plate mudguard plate 14 positioned behind the shock absorber 6 is fixed on the connecting plate 2A extending between the pair of left and right rear arms 2, 2. The mudguard plate 14 is fixed on the connecting plate 2A by brackets 14A, 14A provided at the lower ends of both ends, and the bracket 1 provided at the lateral end.
It is fixed to the inner side wall of the chain cover 13 by 4B. Due to this fixing, the mudguard plate 14 and the chain cover 13 are in a relationship orthogonal to each other.

Therefore, the mudguard plate 14 prevents the mud splashed by the rear wheel 3 from polluting the shock absorber 6 and maintaining its function. Also, the mudguard plate 14 and the chain cover 13
Since the mudguard plate 14 is integrally fixed so as to intersect with, even if the mudguard plate 14 is formed of a thin plate, the rigidity in the front-rear direction of the vehicle body is increased. Further, since the chain cover 13 is also fixed to the mudguard plate 14, the rigidity of the vehicle body in the left-right direction is increased and becomes stable.

(Effects of the Invention) As described above, the chain cover device for a motorcycle according to the present invention pivotally supports the base end portions of the pair of left and right rear arms that support the rear wheels on the lower rear portion of the frame, while swinging the left and right arms. In a motorcycle in which a connecting plate is passed between a pair of rear arms and a shock absorber that elastically supports the rear arm is arranged at the center position of the vehicle body between the connecting plate and the base end, the chain cover is made of synthetic resin. Made in a reverse U-shape in cross section, notches are provided in the inner side wall of the front and rear intermediate part of the chain cover, the bracket hangs downward from the lower end edge of the outer side wall of the rear part of the chain cover, and this is used as a rear arm. One side of the chain cover was screwed from the side, and a bracket was extended from the lower edge of the inner side wall of the front part of the chain cover and screwed to the upper surface of the connecting plate from above. When viewed from the vehicle front-rear direction, the brackets are located on the left and right of the center of the inverted U-shaped cross section, the chain cover is a double-supported beam, and when viewed from the vehicle left-right direction, the rear bracket is the rear arm. Since it is screwed from the side, it corresponds to the so-called rotating end of the beam, but the bracket on the front side corresponds to the so-called fixed end of the beam because it is screwed in the vertical direction to the upper surface of the connecting plate. The strength of the beam is higher than that of the conventional one in which the bracket is located at a position deviated from the center of the cross section, the chain cover is a cantilever beam, and the brackets are all rotating ends.

Therefore, for weight reduction and cost reduction, even if the material of the chain cover is synthetic resin, notches are provided in the front and rear intermediate parts of the chain cover in order to reduce the width of the vehicle in the left-right direction and make it compact. Also, it is possible to prevent damage from the base of the bracket and the notch.

Also, since the outer side wall of the front part of the chain cover and one outer surface of the rear arm are aligned, and the front part of the chain cover is extended to the vicinity of the base end part of the rear arm, the chain is sufficiently covered to prevent dirt. Prevents adhesion and prolongs chain life.

Moreover, even if the front portion of the chain cover is extended in this way, the outer side wall of the front portion does not extend outside the rear arm, so that even if the chain cover moves up and down, the base end portion of the rear arm does not pivot. There is no contact with the frame part. A shock absorber that elastically supports the rear arm is provided at the center of the vehicle body between the base end of the rear arm and a connecting plate extending between the pair of left and right rear arms in the vicinity thereof. Therefore, as in conventional motorcycles, where shock absorbers are attached to the rear sides of the pair of left and right rear arms and the shock absorber and the chain cover are close to each other, it is troublesome to avoid contact between them and to further provide a notch or a recess in the chain cover. Can be omitted. In addition, a mudguard plate made of synthetic resin was placed between the front part of the rear wheel and the shock absorber, and this mudguard plate was integrally fixed so as to intersect the inner side wall of the chain cover. It is possible to prevent the occurrence of damage and to increase the rigidity of both the mudguard plate and the chain cover, making it possible to achieve a firm attachment that does not cause damage while making the whole thinner.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of a rear portion of a motorcycle equipped with a chain cover device of the present invention, FIG. 2 is a plan view showing the same device, and FIG. 3 is a perspective view thereof. 1 ... Frame, 2 ... Rear arm 2A ... Connecting plate, 3 ... Rear wheel 6 ... Shock absorber, 9 ... Chain 13 ... Chain cover, 13B, A ... Bracket 14 ... Mudguard plate

Claims (1)

[Claims] 1. A pair of left and right rear arms that support rear wheels are rotatably pivotally supported at a lower rear portion of a frame, and
A motorcycle in which a connecting plate is passed between the pair of left and right rear arms, and one shock absorber that elastically supports the rear arm is arranged at a center position of the vehicle body between the connecting plate and the base end portion. Is made of synthetic resin and has an inverted U-shaped cross section, and a notch is provided in the inner side wall of the front and rear intermediate part of the chain cover, and the bracket is hung downward from the lower end edge of the outer side wall of the rear part of the chain cover. Is screwed to one rear part of the rear arm from the side, and a bracket is extended from the lower end edge of the inner side wall of the front part of the chain cover and screwed to the upper surface of the connecting plate from above,
The outer side wall of the front portion of the chain cover and one outer surface of the rear arm are made to coincide with each other, and the front portion of the chain cover is extended to the vicinity of the base end portion of the rear arm to cushion the front portion of the rear wheel. A chain cover device for a motorcycle, characterized in that a mudguard plate made of synthetic resin arranged between the container and the container is integrally fixed so as to intersect and stand upright with the inner side wall of the chain cover.