JP3780812B2 - Vehicle rear wheel suspension system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a vehicle rear wheel suspension suitable for a low-floor cargo vehicle, particularly a vehicle rear wheel suspension in which a final reduction gear is located at a sufficiently high position from the ground so that a smaller-diameter rear wheel can be used. It relates to the device.
[0002]
[Prior art]
In a conventional rear wheel suspension system such as a truck or RV, a rear wheel, a brake, and the like are attached to an axle case integrated with a final reduction gear, and the axle case is attached on a spring via a vertical leaf spring. The entire axle case is an unsprung component, and the portion of the axle case that accommodates the final reduction gear is most inflated, so the distance between this accommodating portion and the road surface is the ground clearance of the suspension device.
[0003]
In rear-wheel suspension systems such as trucks and RVs that support rigid axle cases on the vehicle frame with a common leaf spring, the axle case has a shape that connects the left and right rear wheels, so the floor or the vehicle frame is lowered to lower the floor. Attempts to achieve this result in the vehicle frame interfering with the axle case and the bump stroke of the suspension device being reduced, resulting in deterioration in performance such as riding comfort and road surface retention (road holding). Therefore, if the rear wheel is reduced in diameter, the vertical stroke of the rear wheel suspension device is left as it is, and the entire vehicle is lowered, the reduction in the diameter of the rear wheel also reduces the ground clearance and hinders driving on ordinary roads. There is a limit to reducing the diameter of the ring.
[0004]
On the other hand, in the de-deion type rear wheel suspension system, a constant velocity shaft joint of the intermediate axle must be provided inside the rear wheel, and the rear side (rear side) of the rear wheel axle (spindle ) becomes huge, The space between the wheel and the vehicle frame is compressed, and the marginal space of the vertically placed half elliptical leaf spring is remarkably reduced. If the axle is supported by a plurality of links without relying on leaf springs, the above problems can be solved to some extent, but the range of modification of the vehicle frame, such as the addition of lateral members, is expanded, and the final reduction gear is de-deionized. Since it is in front of the shaft, the part through which the upper link passes is very limited.
[0005]
A rear wheel suspension disclosed in Japanese Patent Application Laid-Open No. 8-132900 is a cargo vehicle that supports a final reduction gear at a front point and a rear point under a floor of a monocoque vehicle, and has a large load. It is difficult to apply.
[0006]
[Problems to be solved by the invention]
In view of the above problems, an object of the present invention is to provide a rear wheel suspension device for a vehicle that satisfies a required rebound stroke and a required inclination angle of an intermediate axle.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the configuration of the present invention includes a pair of left and right columns attached to left and right vehicle frames, a final reduction gear fixed between a pair of left and right columns, and outputs of the final reduction devices. An intermediate axle connected to the gear shaft by a constant velocity joint, a rear axle for transmitting driving force to a rear wheel connected to the intermediate axle by a second constant velocity shaft joint, and a second constant velocity shaft joint A forearm that protrudes forward and a rear arm that protrudes backward, coupled to the covering case, a quarter elliptical leaf spring having a front end coupled to the left and right vehicle frames, and a rear end coupled to the forearm, the forearm and the left and right Hydraulic shock absorbers respectively connected to the vehicle frame, coil springs interposed between the left and right vehicle frames and the rear arm, at least one side of the rear arm and the opposite side of the left and right vehicle frames And a Panard rod connected between the two
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, in a low-floor vehicle, in order to obtain a desired rebound stroke and an inclination angle (intersection angle) with respect to the horizontal plane of the intermediate axle, the upper ends of a pair of left and right columns connected to both side walls of the case of the final reduction gear are respectively It is supported on the left and right car frames via a pair of bushings. On the other hand, a pair of output gear shafts of the final reduction gear are connected to a rear axle supporting left and right rear wheels via two constant velocity shaft joints and an intermediate axle, respectively. Connect the forearm and the rear arm projecting forward and backward to the cylindrical case of the constant velocity joint that connects each rear axle and the intermediate axle, and connect the forearm to the rear end of the leaf spring with the front end supported by the vehicle frame. In addition, a hydraulic shock absorber is connected between the forearm and the vehicle frame. On the other hand, the left and right rear arms are connected by de-deion cylinders, and at least one of the rear arms is connected to the opposite frame or leg piece at the center of the frame via the Panard rod to ensure the lateral rigidity of the rear wheel suspension system. A coil spring is interposed between each rear arm and the vehicle frame.
[0009]
In short, the final reduction gear separated from the rear axle is attached to the vehicle frame by a pair of left and right pillars, and a coil spring is interposed between the rear portion of the left and right rear axles and the rear frame of the left and right rear axles. To connect to the car frame. In order to satisfy the crossing angle (inclination) of the intermediate axle, the stroke from the empty vehicle to the loaded vehicle is reduced in the entire stroke of the rear wheel suspension device to ensure a sufficient rebound stroke.
[0010]
【Example】
As shown in FIGS. 1 and 2, a hollow forearm 5 having a rectangular cross section protruding forward is provided in a cylindrical case 9 of a constant velocity shaft joint that connects a rear axle and an intermediate axle for transmitting driving force to a rear wheel 14. And a hollow rear arm 15 projecting rearward and obliquely inward (in the vehicle width center direction) are joined by welding. The rear end of the quarter elliptical leaf spring 13 and the seat plate 6 are overlapped on the upper wall of the forearm 5, and the seat plate 7 is overlapped on the lower wall 5a of the forearm 5. The seat plate 6, the leaf spring 13, the forearm 5 and the seat plate 7 are held by a pair of front and rear U bolts 8 passing through the seat plate 6 and the seat plate 7, and a nut is screwed to the lower end of the U bolt 8. Are integrally coupled. The hydraulic shock absorber 3 is connected between an inwardly projecting horizontal pin 3 b coupled to the front end of the seat plate 7 and an inwardly projecting horizontal pin 3 a coupled to the vehicle frame 2. The leaf spring 13 curved in a quarter elliptical shape is supported by a pin 12 so as to be swingable by a support plate 10 having a front end eyeball portion coupled to the lower surface of the vehicle frame 2. As shown in FIG. 3, a rubber spring 25 as a rebound stopper is coupled to the lower surface of the support plate 24 supported by the vehicle frame 2 so as to face the seat plate 6.
[0011]
Between the upper wall and the lower wall 15a of the rear end portions of the left and right rear arms 15, a cylinder 19 that is a de Deion cylinder having a substantially square cross section is sandwiched and connected by welding or the like. A pin 18 protruding rearward is coupled to the cylinder 19. The left end of the Panard rod 21 is connected to the left rear arm 15 via the bush 20 by the pin 18. The right end of the Panard rod 21 is connected via a bush 22 to a leg piece 23 that protrudes downward from the right vehicle frame 2. A coil spring 16 is interposed between the spring seat 16 b coupled to the upper surface of the rear arm 15 and the spring seat 16 a coupled to the lower surface of the vehicle frame 2.
[0012]
As shown in FIGS. 3 and 4, a pair of left and right support columns 41 projecting upward are coupled to both side walls of the final reduction gear case 51 by a plurality of bolts 42. The support column 41 has a groove shape in the horizontal cross section, and arc-shaped portions 41 a formed on the front and rear walls of the upper end portion of the support column 41 are joined to the outer cylinder 32 of the bush 4 by welding or the like. The bush 4 has a buffer rubber 33 baked between the outer cylinder 32 and the inner cylinder 34, and the upper end of the bottom plate 35 in contact with the lower surface of the buffer rubber 33 and the bolt 36 passing through the inner cylinder 34 of the reinforcing plate 2 a of the vehicle frame 2. The nut 36a is screwed and fastened through the upper wall. As shown in FIGS. 3 and 5, the output gear shaft (side gear shaft) 52 of the final reduction gear is connected to the intermediate axle 54 by a constant velocity shaft joint 53, and the intermediate axle 54 is connected to the rear axle 55 by a constant velocity shaft joint 9a. Is done.
[0013]
As shown in FIG. 6, the left and right vehicle frames 2 are connected by a plurality of lateral members 57 and 58. A reinforcing member 5 b is coupled to the joint between the forearm 5 and the cylindrical case 9. The reinforcing member 5b is of a cross-sectional groove type formed by connecting a pair of upper and lower triangular plates and a wall plate protruding rearward and obliquely outward from the forearm 5.
[0014]
As described above, according to the present invention, the final reduction gear case 51 is supported by the reinforcing plates 2a of the left and right vehicle frames 2 via the pair of front and rear bushes 4 by the pair of right and left cross-sectional grooves 41. Therefore, the final reduction gear case 51 is arranged at a high position from the road surface, and the required ground clearance is obtained. The output gear shaft 52 of the final reduction gear case 51 is connected to a rear axle 55 that transmits driving force to the rear wheel 14 via a constant velocity shaft joint 53, an intermediate axle 54, and a constant velocity shaft joint 9a. The forearm 5 coupled to the cylindrical case 9 of the constant velocity shaft joint 9 a is coupled to a leaf spring 13 extending rearward from the vehicle frame 2, and the hydraulic shock absorber 3 is coupled between the forearm 5 and the vehicle frame 2. The rear arms 15 coupled to the left and right cylindrical cases 9 are respectively connected by de-deion cylinders 19, and the left rear arm 15 is connected to the right vehicle frame 2 by a panard rod 21, and each rear arm 15 and the vehicle frame 2 are connected to each other. A coil spring 16 is interposed therebetween. The left and right rear wheels 14 are independent of the final reduction gear case 51 and move up and down in response to changes in the road surface. At this time, the cylindrical case 9 swings up and down around the pin 12 together with the leaf spring 13, and the vertical vibration of the left and right cylindrical cases 9 is suppressed by the coil spring 16. Further, the lateral displacement of the left and right rear wheels 14 is suppressed by the Panard rod 21. The rubber spring 25 suppresses excessive upward movement (rebound) of the rear wheel 14 with respect to the vehicle frame 2 when the vehicle passes through the protrusion on the road surface.
[0015]
【The invention's effect】
As described above, the present invention includes a pair of left and right support columns attached to the left and right vehicle frames, a final reduction gear fixed between the pair of left and right support columns, and a constant speed on each output gear shaft of the final reduction device. An intermediate axle connected by a shaft joint, a rear axle for transmitting driving force to a rear wheel connected to the intermediate axle by a second constant velocity shaft joint, and a case covering the second constant velocity shaft joint Between the forearm projecting forward and the rear arm projecting rearward, a quarter elliptical leaf spring having the front end coupled to the left and right car frames and the rear end coupled to the forearm, and the forearm and the left and right car frames Between each of the hydraulic shock absorbers connected to each other, coil springs interposed between the left and right vehicle frames and the rear arms, and at least one side of the rear arms and the one on the opposite side of the left and right vehicle frames. Since the Panard rod connected to is provided, the following effects can be obtained.
[0016]
By making the final reduction gear with the lowest ground clearance almost the same height as the vehicle frame and reducing the diameter of the rear wheels, the floor can be made lower than the conventional one. Since the final reduction gear has nothing to do with the components of the rear wheel suspension device, it can be raised to a position where a sufficient ground clearance can be secured. In addition, the final reduction gear has moved onto the spring, and the unsprung weight can be reduced.
[0017]
A quarter elliptical leaf spring is used as a trailing arm, the longitudinal position of the axle is regulated, a coil spring is interposed between the vehicle frame and the rear arm to support vertical load, and lateral rigidity is achieved by the Panard rod. Therefore, the longitudinal force acting on the rear axle can be received in the form of a leaf spring that is normally used.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a rear wheel suspension device for a vehicle according to the present invention.
FIG. 2 is a side sectional view of a main part of the rear wheel suspension device.
FIG. 3 is a rear view of the rear wheel suspension device.
FIG. 4 is a rear sectional view of the main part of the rear wheel suspension device.
FIG. 5 is a rear view of the rear wheel suspension device.
FIG. 6 is a bottom view of the rear wheel suspension device.
[Explanation of symbols]
2: Vehicle frame 3: Hydraulic shock absorber 4: Bush bush 5: Forearm 6: Seat plate 7: Seat plate 8: U bolt 9: Cylindrical case 9a: Constant velocity shaft joint 13: Leaf spring 14: Rear wheel 15: Rear arm 16: Coil spring 21: Panar rod 25: Rubber spring 41: Post 51: Final reduction gear case 52: Output gear shaft 53: Constant velocity shaft joint 54: Intermediate axle 55: Rear axle

Claims (1)

A pair of left and right columns attached to the left and right vehicle frames; a final reduction gear sandwiched and fixed between the pair of left and right columns; an intermediate axle connected to each output gear shaft of the final reduction device by a constant velocity shaft joint; A rear axle for transmitting a driving force to a rear wheel connected to the intermediate axle by a second constant velocity shaft joint, a forward forearm coupled to a case covering the second constant velocity shaft joint, and a rearward direction A protruding rear arm, a quarter elliptical leaf spring having a front end coupled to the left and right vehicle frames, a rear end coupled to the forearm, and a hydraulic shock absorber coupled between the forearm and the left and right vehicle frames, respectively A coil spring interposed between the left and right vehicle frames and the rear arm, and a Panard rod connected between at least one side of the rear arm and the opposite side of the left and right vehicle frames. A rear-wheel suspension device for a vehicle.

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