JPH0764292B2 - Rear wheel suspension system for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rear wheel suspension device in a vehicle in which a final reduction gear is integrally formed on a rear axle that is held so as to be vertically movable.

(Background of the Invention) A vehicle in which a final reduction gear case is integrally formed on a rear axle that holds a pair of left and right driving rear wheels, and the rear axle is vertically movably attached to a vehicle body frame by an upper arm and a lower arm in the front-rear direction. It is considered. In this type of vehicle, since the diameter of the final reduction gear case is large, the road clearance near the lower edge of the final reduction gear case approaches the road surface and the final reduction gear case contacts an obstacle on the road surface. It will be easier. Therefore, there is a problem that the final reduction gear case is easily damaged.

Therefore, it is conceivable to fix a protective member that covers the bottom of the final reduction gear case to the final reduction gear case or to the vehicle body frame. However, when fixed to the final reduction gear case, not only the road clearance is further reduced, but also the unsprung weight of the rear wheel suspension system is increased and the running performance on rough roads is deteriorated. In addition, when fixing to the vehicle body frame side, the distance between the protective member and the road surface decreases as the shock absorber of the rear wheel suspension system is compressed, and this protective member hits an obstacle to reduce the bad road running performance. .

Further, if such a protective member is separately provided, there is a problem that the weight increases.

(Object of the invention) The present invention has been made in view of the above circumstances, and can protect the final reduction gear case without separately providing a protective member for the final reduction gear case, and the road clearance is always large. An object of the present invention is to provide a rear wheel suspension system for a vehicle, which can be secured and does not cause deterioration of traveling performance on bad roads and increase in weight due to an increase in unsprung weight.

(Structure of the Invention) According to the present invention, an object is to provide an engine mounted on a vehicle body frame so that a crankshaft is arranged in a vehicle body width direction, and a rear axle integrally formed with a final reduction gear case, A pair of left and right drive rear wheels attached to the left and right of the rear axle,
In a vehicle including a pair of left and right lower arms each having a front end attached to a vehicle body frame and a rear end attached to the rear axle, and a shock absorber for urging the rear axle downward, power is extracted from a rear side of the engine. Power is transmitted to the final reduction gear via an extendable drive shaft, and the final reduction gear housing that houses this final reduction gear is displaced to one side of the vehicle body, and one lower arm and the rear wheel on the same side as this And a part of the lower arm is located inside the rear wheel, and the lower arm is substantially convex in the vicinity of the center so that the lower arm is convex above and below the line connecting the front end shaft attachment portion of the lower arm and the axis of the rear axle. It is curved in an arc shape, the lower edge near the center of the lower arm is located below the final reduction gear case and the rear part of the body frame, and the lower end of the shock absorber is pivotally supported on the upper surface of the rear axle. Achieved by the rear wheel suspension system of the vehicle, .

(Embodiment) FIG. 1 is a side view of a four-wheeled vehicle for traveling on rough terrain, which is an embodiment of the present invention, FIG. 2 is a plan view showing a rear wheel suspension device, and FIG. 3 is a rear view.

In these drawings, reference numeral 10 is a vehicle body frame, which includes a pair of left and right large-diameter lower tubes 12 (12a, 12b) and a pair of left and right upper tubes 14 (14a, 14b). Lower tube 12
The front part of the upper tube is bent upward in a hook shape, and the front end of the upper tube is fixed to the bent end. Two bases of a pair of left and right lower arms 16 of substantially A type (only one is shown) are swingably attached to the lower front part of the lower tube 12 so as to swing freely.
A tubular shock absorber 18 (only one of which is shown) is interposed between the swinging end 16 and the front upper portion of each lower tube 12. A knuckle bracket (not shown) is fixed to the lower portion of the tubular shock absorber 18, and the front wheel 20 is attached to the knuckle bracket.
A knuckle (not shown) for holding is attached by a king pin so as to be rotatable left and right. As a result, a well-known strut-type independent suspension system is formed, and a pair of left and right front wheels 20 is formed.
(Only one is shown) is held so that it can move up and down. The first
In the figure, reference numeral 22 denotes a steering shaft, the lower end of which is supported by a bracket 24 which connects the front lower parts of both lower tubes 12 and the upper part of which is supported by an arc-shaped cross tube 26 which connects both upper tubes 14. A steering bar handle is provided on the upper end of the steering shaft 22.
28 is fixed.

The vicinity of the center of both lower tubes 12 are connected to each other by cross tubes 30 and 32, and an engine 34 is mounted above these cross tubes 30 and 32. The crankshaft of the engine 34 is arranged in the vehicle width direction.

The rear part of the left lower tube 12a extends substantially horizontally to the rear of the cross tube 32, and the rear part is bent upward in a crank shape. Right lower tube 12b is cross tube 3
After standing up from around 2, it extends diagonally upward and rearward. The right end of a cross tube 36 located above the cross tube 32 is fixed to the right lower tube 12b, and a pair of left and right standing tubes 38 (38a, 38a) of the cross tube 36 are fixed.
They are fixed to the upper tube 14 by b). The left end of the cross tube 36 is joined to the left lower tube 12a by a removable vertical bracket 40.

The crank-shaped vertical part at the rear of the left lower tube 12a is formed by the cross tube 42 and the right lower tube 12b.
The cross tube 42 and the cross tube 36 are fixed to each other by a tube 44 in the front-rear direction.

Reference numeral 46 denotes a rear axle, and a right end portion of the rear axle 46 is integrally formed with a final reduction gear case 48 that accommodates a final reduction gear including a differential gear. A pair of left and right rear wheels 50 (50a, 50b) are held at both ends of the rear axle 46, and rotation is transmitted from the final reduction gear to each of the rear wheels 50 by the rear axle 52 inserted through the rear axle 46.

54 (54a, 54b) is a pair of left and right lower arms, the front end of which is pivotally attached to the cross tube 32 so as to be vertically swingable,
The rear end is pivotally attached to the lower surface of the rear axle 46. The final reduction gear case 48 is located outside the right lower arm 54b.

Here, both lower arms 54 are parallel to the front-rear direction, and a part of the final reduction gear case 48 enters the inside of the right rear wheel 50b. Further, the lower arm 54 is curved in a substantially arcuate shape so that the vicinity of its center is convex upward from the line connecting the front end shaft attachment portion of the lower arm and the axis of the rear axle, and the final reduction gear case 48 has the center of the lower arm 54. It is located above the lower edge of the neighborhood. The lower tube 12 of the body frame 10 has a lower arm at the rear.
It is higher than the lower edge of 54 (see Figures 1 and 3).

Reference numeral 56 is an upper arm whose front portion is bifurcated, the two front ends of which are pivotally attached to the cross tube 36 and the right lower tube 12b so as to be vertically movable, and the rear end thereof is a final reduction gear case 48. Is pivoted on top of. Also 58 (58
a and 58b) are a pair of left and right tubular shock absorbers which are interposed substantially vertically between the rear axle 46 and the rear portion of the lower tube 12. Here, the lower end of the shock absorber 58 is pivotally supported on the upper surface of the rear axle 46.

As a result, the rear axle 46 includes the lower arm 54 and the upper arm 56.
And are held so that they can move up and down, forming a double trailing type rear wheel suspension device.

Reference numeral 60 is a transmission case that is long in the front-rear direction and accommodates a transmission device including a transmission gear train. The transmission case 60 is fixed to the vehicle body frame 10 so as to be located inside the vicinity of the left lower tube 12a and above the left lower arm 54a. That is, the left lower tube 12a passes near the outer edge of the transmission case 60, and the lower arm 54a is located below the transmission case 60. The front portion of the transmission case 60 is connected to the rear side surface of the engine 34, and the rear portion thereof extends between the rear wheels 50. Between the rear end of the transmission case 60 and the final reduction gear case 48, an extendable drive shaft 62 having cross joints at both ends.
Intervenes in the width direction of the vehicle body, and the rotation of the transmission is caused by the drive shaft 62
Tell the final reducer by.

Reference numeral 64 is a PTO gear case disposed in the space behind the engine 34 and to the right of the transmission case 60. The case 64 is fixed to the cross tube 42 and the tube 44 in the front-rear direction with a bracket (not shown). ing. A bevel gear is housed in the case 64, and the rotation of the driven pulley 66 provided on the left side surface is transmitted to the PTO shaft 68 protruding rearward. A drive pulley 70 is provided near the center of the rear surface of the engine 34, and two V belts 72 are wound around these pulleys 70 and 66. Then, the tension roller 74 changes the tension of the V belt to continue the rotation transmission between the pulleys 70 and 66. That is, the PTO shaft 68 by the V belt type clutch
Rotation is intermittent.

In FIG. 1, 80 is a fuel tank, 82 is a straddle type operation seat,
84 is an intake purifier, 86 is a carburetor, and 88 is an exhaust muffler.
Reference numeral 90 denotes a pair of left and right front fenders, and a luggage box 92 is arranged below the front fenders 90. Reference numeral 94 is a rear fender that is integrated left and right, and a battery 96 is disposed below the rear fender. Further, 98 is a front cargo bed, 100 is a rear cargo bed, and 102 is a front bumper.

According to this embodiment, the rotation of the engine 34 depends on the transmission case 60.
To the final transmission in the final reduction gear case 48 via the drive shaft 62. Then, this rotation is further transmitted to the left and right rear wheels 50 by the rear wheel shaft 52. In addition, the lower tube 12 is placed near the left side edge of the transmission case 60.
Since a is located and the lower arm 54a is located below, obstacles and stones that the rear wheel 50 bounces up during traveling on rough terrain are less likely to hit the transmission case 60, and the transmission case 60 prevents the lower tube 12a and the lower arm from moving. Protected by 54a.

Since the upright bracket 40 on the side of the transmission case 60 can be removed, workability at the time of attaching and detaching the transmission case 60 and maintenance is improved.

Since the lower edge of the lower arm 54 is located below the rear part of the lower gear case 48 and the lower tube 12 of the vehicle body frame 10, when the obstacle runs across both the rear wheels 50, the obstacle is the lower arm 54. Since it hits 54, the final reduction gear case
The lower arm 54 does not hit the lower tube 48 or the lower tube 12, and even if it hits, the lower arm 54 significantly reduces the impact. Therefore, the final reduction gear case 48 is protected.

Further, when the rear wheel 50 moves upward while the rear wheel 50 compresses the shock absorber 58, the lower arm 54 swings upward with it. Therefore, a large road clearance can always be secured.

Further, in the present embodiment, since the lower arm 54 is curved so as to be convex downward, the lower arm 54 can overcome obstacles by a kind of sled action and weaken the impact transmitted to the vehicle body. .

Further, since the final reduction gear case 48 is located outside the right lower arm 54b, it is more difficult for an obstacle to hit the final reduction gear case 48. That is, the right rear wheel 50 and the lower arm
The space between 54b and the final reduction gear case 48 is narrow.
Is close to these.

The present invention can be applied to a three-wheeled vehicle having one front wheel,
Such things are also included.

(Effects of the Invention) As described above, according to the present invention, since the lower edge of the lower arm is located below the final reduction gear case and the rear part of the vehicle body frame, the lower arm itself serves as a protective member for the final reduction gear case, and a separate protective member. It is possible to protect the final reduction gear case without providing. Further, since the lower arm moves up and down as the rear wheel moves up and down, a large road clearance can be secured at all times, the unsprung weight does not increase, and the traveling performance on bad roads and the weight increase do not occur.

In addition, the lower arm is curved so that its central portion is convex downward, and the lower central portion is lower than the rear portion of the body frame, so that the lower arm has a sleding action to smoothly overcome obstacles. You can Furthermore, since the final reduction gear case is arranged so that a part of it goes into the inside of the rear wheel between one of the lower arms and the rear wheel on the same side, obstacles on the road surface are even more prominent in this final reduction gear case. Hard to hit. Since the lower end of the shock absorber is pivotally supported on the upper surface of the rear axle, the position of the shock absorber is increased and the shock absorber can be sufficiently protected from obstacles.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a plan view showing a rear wheel suspension device, and FIG. 3 is a rear view. 10 …… Body frame 46 …… Rear axle 48 …… Final reduction gear case 50 …… Rear wheel 54 …… Lower arm 56 …… Upper arm 58 …… Shock absorber

Claims (1)

[Claims] 1. An engine mounted on a vehicle body frame so that a crankshaft is arranged in a vehicle width direction, a rear axle integrally formed with a final reduction gear case, and attached to the left and right of the rear axle. A vehicle comprising a pair of left and right driving rear wheels, a pair of left and right lower arms having front ends attached to a body frame and rear ends attached to the rear axles respectively, and a shock absorber for urging the rear axles downward. The power is transmitted from the rear one side to the final reduction gear via the extendable drive shaft, and the final reduction gear housing that houses this final reduction gear is biased to one side of the vehicle body and A part of the lower arm is located inside the rear wheel between this and the rear wheel, and the lower arm is located near the center below the line connecting the front end shaft attachment portion of the lower arm and the rear axle shaft core. Curve it in a generally arcuate shape so that it becomes convex to A rear wheel suspension system for a vehicle, wherein a lower edge near the center of the lower arm is located below the final reduction gear case and the rear part of the body frame, and a lower end of the shock absorber is pivotally supported on an upper surface of a rear wheel. .