JPH04123982A - Rear-wheel steering system in vehicle - Google Patents

Abstract

PURPOSE:To improve the extent of steering stability at time of running at high speed by supporting a car width central aprt of a rear axle housing pivotally on a top part of a V-shaped upper radius rod, and suspending each spot of both ends in the car width derection on an undercarriage frame by means of each laminated spring gear. CONSTITUTION:A top part of a V-shaped upper radius rod 52 installed along a center line in the longitudinal direction of a car body is pivotally supported on the upper side of a differential casing 56 installed in the central part of a rear axle housing 16 via a ball joint unit 54, and both leg ends of the rod 16 are pivotally attached to a side rail 12 of the undercarriage frame 10. The rear axle housing 16 is steered and rotated by a hydraulic cylinder unit 72 via a lower radius rod 64. In addition, the rear axle housing 16 is connected to each of laminated spring gears 20, 28 via rubber layers 38, 46 being installed at both vertical sides of the double end part and compressed in the vertical direction, allowing the upper radius rod 52 to rotate around a top pivoting point by means of each shearing deformation of these of rubber layers 38, 46.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rear wheel steering device for a vehicle, particularly a truck.

(Prior Art) In recent years, various four-wheel steering systems and devices have been proposed in which rear wheels are steered in conjunction with front wheel steering in order to improve steering stability during high-speed driving.

However, all conventional four-wheel steering systems are related to vehicles, mostly passenger cars, in which the front and rear wheels are independently suspended, and the rear wheels are supported within a rigid axle tube or rear axle housing. In particular, a four-wheel steering device for a truck or the like in which double tires are used for the rear wheels has not yet been proposed.

(Problems to be Solved by the Invention) The present invention provides a novel and useful rear wheel that can improve the steering stability during high-speed running in a truck or the like in which the rear wheels are supported at both end portions in the vehicle width direction of a rear axle housing. The object of the present invention is to provide a steering device.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a chassis frame, a rear axle housing that supports rear wheels at both ends in the vehicle direction, and a space between the rear axle housing and the chassis frame. The interposed stacked leaf spring device is disposed along the center line in the longitudinal direction of the vehicle body, and its apex portion is pivotally connected to the center portion of the rear axle housing in the vehicle +IJ direction, and the free end portions of both legs are respectively pivoted to the vehicle chassis frame. a pair of left and right lower radius rods that are arranged approximately symmetrically on both sides of the center line in the longitudinal direction of the vehicle body and whose respective ends are pivotally connected to the rear axle housing; They are respectively connected to the other ends of the unoas rods and actuated during steering when the vehicle is running at high speed to drive the left and right lower radius rods in opposite directions and rotate the rear axle housing around the pivot point of the apex of the upper radius rod. The rear axle housing is further provided with a pair of rear wheel steering actuators disposed on both upper and lower ends of the rear axle housing and connected to the stacked leaf spring device through two downwardly compressed rubber layers. The present invention proposes a rear wheel steering device for a vehicle, characterized in that the rear axle housing is allowed to rotate around the apex pivot point of the upper radius rod by shearing deformation of the rubber layer.

(Function) According to the present invention, the rear axle 1 housing is
Since the central portion in the direction is suspended by the figure 7-shaped upper radius slot, it is possible to rotate around the apex pivot point of the upper radius rod, in other words, rear wheel steering is possible. The steering movement of the rear axle housing is controlled by a pair of rear wheel steering actuators that operate a pair of left and right lower radius rods whose respective ends are pivotally connected to the rear axle housing in opposite directions.

(Example) Examples of the present invention will be specifically described below with reference to the accompanying drawings. Reference numeral 10 in the figure is a chassis frame of a vehicle such as a truck, which includes a pair of left and right sight rails 12 extending in the longitudinal direction of the vehicle body, and a plurality of sight rails 12 extending in the vehicle width direction and having both ends fixed to the left and right sight rails 12. The cross member 14 is made up of two cross members 14.

A rear axle how song 16 supports a double tire 18 at both end portions in the vehicle width direction, and a rear axle how song 20 is supported at both front and rear ends by the sight rail 12 of the chassis frame 10 via a shackle bin 22, a shackle link 24, and a shackle bracket 26. main leaf spring, 2
Reference numeral 8 denotes a Hertz 4 leaf spring which is disposed above the main leaf spring 20 and whose front and rear ends slide into contact with the Hertz stopper 30 attached to the sight rail 12 when the vehicle load exceeds a set load. , 32 is the substrate 34
An upper rubber knot member 40 is made up of a contact plate 36 that comes into contact with the upper surface of the rear axle housing 16 and a rubber layer 38 that is baked and fixed to the base plate and the contact plate. Contact plate 44
and a lower rubber pad member consisting of a rubber layer 46 baked and fixed to the substrate and the contact plate; 48 is the substrate 34 and the substrate 42;
By tightening the U port 50 inserted between them and inserted therein, a required compressive force is applied to the rubber layers 38 and 46, and the rear axle housing 16 is compressed to the main leaf spring 20 and the Hertz 9 through these rubber layers. This is a spacer made of Noeib material that connects to the leaf spring 28. (In the illustrated embodiment, the stacked leaf spring device for rear wheel suspension is composed of a main leaf spring 20 and a Hertz 4 leaf spring 28.
Hertz'? The IJ spring 28 may be omitted. ) 52 is an upper radius rod arranged along the center line in the longitudinal direction of the vehicle body and having a figure 7 shape in plan view;
The apex of the radius rod is the He-ru joint device 5.
4 (or an equivalent rubber fitting 7-type gearing device) to the two sides of the differential casing 56 provided in the center of the rear axle housing 16, and the free ends of both legs of the rod. are each pivotally connected to the sight rail 12 (or cross member 14) of the chassis frame 10 via a pole joint device 58 (or an equivalent rubber bush type joint device).

Particularly, as clearly shown in FIG. 2, a bracket 60 is fixed to the side surface near both ends of the rear axle housing 160 in the vehicle rl direction by welding or other suitable fixing means, and the bracket 60 is attached to the rear axle housing 160. (
One end of a pair of left and right lower radius rods 64 is pivotally connected via a rubber push-type joint device with the same effect. The other end of each lower radius rod 64 is connected to a bracket 66 fixed to the web or side wall of the site rail 12.
They are each pivotally connected via a pin 72 to one end of a bell crank-shaped operating lever 7o which is pivotally supported by a pin 68.

Furthermore, a piston shaft 74 of a hydraulic cylinder device 72 forming a pair of left and right rear wheel steering actuators is pivotally connected to the other end of the operating lever 7o by a pin 76, and a cylinder 78 of the hydraulic cylinder device is connected by a pin 8o. It is pivotally supported on the web or side wall of the sight rail 12.

The specific structure of the above-mentioned joint devices 54+58 and 62 is illustrated in FIGS. 4 and 5. First,
In FIG. 4, reference numeral 82 indicates one member that causes relative rotational displacement, that is, the upper radius rod 52 or the lower radius rod 64, and 84 indicates the other member, that is, the rear axle housing 16 or the bracket 60. A shaft 88 having a spherical member 86 is supported on the other member 84, and a ball seat 90 which abuts on the spherical member 86 is supported on the one member 82. With this configuration,
One member 82 can freely rotate relative to the other member 84 within a plane perpendicular to the axis of the shaft 88 and within a plane including the axis. Also, the pole joint device shown in FIG. - A housing 96 is formed to accommodate the ball head 94 of the pole stud 92, and ball seats (98 and 100) that abut the ball head 94 are interposed in the housing 96, and the pole stud 92 is connected to the other member. 84, that is, it is fixed to the rear axle housing 16 or the bracket 6o. With this structure as well, one member 82 is fixed to the other member 84 in a plane perpendicular to the axis of the goal stand 92 and in a plane including the coaxial line. They can rotate freely relative to each other.

Furthermore, FIG. 6 shows a rubber bush type joint device which is functionally almost the same as the ball joint device described above. A comb push 1.02 is baked and fixed to the end of one member 82 similar to that shown in FIG.
A spherical member 86 is simultaneously baked and fixed to the inner periphery of the spherical member 86 .

A shaft 88 supported by the other member 84 similar to the above is inserted through the spherical member 86 . Also in this configuration, relative rotation is allowed between the one member 82 and the other member 84 in a plane perpendicular to the axis of the shaft 88 and in a plane including the axis.

Finally, FIG. 7 is a conceptual diagram of a device for controlling the operation of the rear wheel steering actuator 72.

In the figure, reference numeral 104 is a steering angle sensor, for example, a non-contact light/glue type that is installed in the steering shirt l-1, 06 and detects the steering angle, 108 is a vehicle speed sensor, 110 is a yaw rate sensor, and 112 is a steering angle sensor. 1o4 steering angle signal, vehicle speed signal of vehicle speed sensor 108, and yaw rate sensor 11
The rear wheel steering actuator 72 receives the turning signal of 0.
a controller that controls a control valve 114 that operates the
16 is a hydraulic pump.

When the vehicle is traveling at high speed, when the steering wheel 118 is operated and the front wheels 120 are steered, a steering angle signal from the steering angle sensor 104, a vehicle speed signal from the vehicle speed sensor 108, and a turning signal from the yaw rate sensor 1]0 are transmitted. The controller 112 receives the signal and issues a drive signal to the control valve 114, thereby operating the control valve. The high-pressure hydraulic oil discharged from the hydraulic bonnet 116 by the operation of the control valve 114 is supplied to the pair of rear wheel steering actuators 72.
2 operates in opposite directions, that is, when one of the left and right actuators extends, the other actuator contracts.

When steering the rear wheels for the purpose of improving steering stability when the vehicle is running at high speed, the rear wheels 18 are usually steered by a small steering angle, for example, about 1 to 5 degrees, in the same direction as the front wheels 120. be done. However, in connection with the steering of the front wheels 120, the rear wheels 18 are first steered by a slight angle in the opposite direction to the steering direction of the front wheels 120, and after an instant, the rear wheels 18 are steered by a slight angle in the same direction as the steering direction of the front wheels 120. It is also possible to employ a rear wheel steering system that steers the vehicle.

In the above configuration, the cylinder 781C of the hydraulic cylinder device 72 forming the rear wheel steering actuator has a built-in stopper that limits the extension and contraction strokes of the piston shaft 74.
When the hydraulic cylinder device 72 is in operation, the rear axle housing 16, that is, the rear wheel 18, is correctly steered by a preset small steering angle of 1 to 5 degrees, for example, 1 degree. The piston is locked in the neutral position by the action of a neutral spring or hydraulically (equal hydraulic pressure is applied to both chambers of the piston to fix the piston in the neutral position).
As a result, the piston shaft 74 is fixed at the neutral position,
The rear axle song 16, ie, the rear wheel 18, is maintained in a straight-ahead state with zero steering angle.

When the front wheels 120 are steered while the vehicle is running at high speed, the control valve 114 is activated by a command from the controller 112 as described above.
is activated, and the pair of rear wheel steering actuators 72 are activated in opposite directions. Piston shaft 7 of each actuator
The operating levers 70 connected at one end to each of the operating levers 70 rotate in opposite directions, and the lower radius rod 64 connected to the other end of one of the operating levers 70 is pulled toward the front of the vehicle, and the other operating lever 70 rotates in opposite directions. A lower radius rotor 4 connected to the other end is driven toward the rear of the vehicle body. As a result, the rear axle housing 16 has a 7-shaped upper radius rod 5.
The steering wheel is rotated around the apex of 2 in either the left or right direction by a set steering angle, for example, 1 degree, and the steering stability during high-speed steering is improved in a manner well known in the art. When the rear axle housing 16 rotates for steering, the compressed rubber layers 38 and 46 in the upper rubber pad member 32 and the lower rubber pad member 40 disposed on both the upper and lower sides of the rear axle housing flexibly shear deform. This makes the process extremely smooth.

- TJj while the vehicle is still going straight or turning when steering.
Rear axle housing 16 to platform seam 10
The vertical movement of the upper and lower rubber throat members 32 and 4
The main axle housing 16 receives the load through the main nose rod 52 and the helper leaf leaf ring 28 (on the one hand, the main axle housing 16 receives the load on the other hand). The ass rod 64 performs parallel link movement up and down.

In addition, the upper radius rod 52 is pivotally connected to the rear axle nose housing 16 and the undercarriage frame 10 by ball joint devices 54 and 58 (or equivalent rubber-button joint devices), and the lower radius rod 64
is connected to the rear axle 1 by a similar pole joint device 62 (or a rubber brush joint type joint device with the same effect).
Since it is pivotally attached to the housing 16, even if the rear axle 1 housing 16 tilts from side to side or rolls when traveling on an uneven road or when turning, its displacement is not hindered.

In addition, in the above embodiment, a vehicle with one rear axle is illustrated, but in the case of a vehicle with two rear axles, a rear wheel steering device similar to that described above may be provided on both the rear front axle and the rear axle. It will be done. Furthermore, in vehicles with two rear axles, one of the rear axles is often configured as a dead axle that does not transmit driving force, but the steering device itself is substantially the same as the case of the drive wheels illustrated.

(Effects of the Invention) As described above, the rear wheel steering device in the vehicle according to the present invention includes a chassis frame, a rear axle housing that supports the rear wheels at both ends in the vehicle width direction, the rear axle housing, and the chassis frame described in “2”. A stacked leaf spring device is disposed along the center line in the longitudinal direction of the vehicle body, and its apex is pivotally connected to the center portion of the rear axle housing in the vehicle width direction. A pair of left and right radius rods each having a 7-shaped planar shape are pivotally connected to the vehicle chassis frame, and a pair of left and right radius rods are arranged approximately symmetrically on both sides of the center line in the longitudinal direction of the vehicle body, and one end of each is pivotally connected to the rear axle housing. The lower radius rod is connected to the other end of the lower radius rod, and is activated when the vehicle is steered while running at high speed to drive the left and right lower quadrature rods in opposite directions to move the rear axle housing to the apex of the upper radius rod. The rear axle housing is provided with a pair of rear wheel steering actuators that are rotated around a pivot point, and the rear axle housing is arranged on both the upper and lower sides of both ends of the rear axle housing and is connected to the stacked plate through rubber layers that are compressed in the vertical direction. The device is connected to a spring device and configured to allow rotation around a pivot point at the top of the upper radius rod of the rear axle housing by shearing deformation of the rubber layer, and includes a rigid rear axle tube. This is industrially advantageous because it can improve the steering stability of trucks and other vehicles traveling at high speeds.

[Brief explanation of drawings]

FIG. 1 is a plan view of a main part showing an embodiment of the present invention, FIG. 2 is a side view of the rear wheel steering device shown in FIG. 1, and FIG. 3 is a side view of the rear wheel steering device shown in FIG. 1. Schematic plan view of the device, FIGS. 4 and 5
The figure shows the Mr. H-luge joint device 54 in the device shown in FIG.
．． , 58 and 62 are cross-sectional views showing specific structures, respectively;
FIG. 6 is a sectional view of a rubber bush type joint device having approximately the same effect as the gold joint device shown in FIGS. 4 and 5;
FIG. 7 is a schematic diagram of an operation control device for the rear wheel steering actuator 72 in FIG. 1. 10... Chassis frame, 12... Zydrail, 1
6... Rear axle how song, 2o... Main leaf spring, 28... Herno leaf sling, 32... Upper comb hat member, 40... Lower rubber pad member, 52... Upper radius rod, 54 ．．
58 Tsubabi 62...Ball joint device, 64...
Lower runo' soar rod, 70... Operating lever 72... Rear wheel steering actuator.

Claims (1)

[Claims] An undercarriage frame, a rear axle housing that supports the rear wheels at both ends in the vehicle width direction, a stacked leaf spring device interposed between the rear axle housing and the undercarriage frame, and a stacked leaf spring device arranged along the longitudinal center line of the vehicle body. an upper radius rod having a V-shaped planar shape, the apex of which is pivotally connected to the center portion of the rear axle housing in the vehicle width direction, and the free end portions of both legs are pivotally connected to the chassis frame, respectively; both sides of the longitudinal center line of the vehicle body; A pair of left and right lower radius rods are disposed approximately symmetrically and one end of each is pivotally connected to the rear axle housing, and the other end of the lower radius rod is connected to the left and right lower radius rods. a pair of rear wheel steering actuators for driving the lower radius rods in opposite directions to rotate the rear axle housing about the apex pivot point of the upper radius rod, the rear axle housing further comprising:
It is connected to the stacked leaf spring device through rubber layers arranged on both upper and lower sides of both ends and compressed in the vertical direction, and the upper radius rod of the rear axle housing moves around the pivot point of the upper radius rod apex by shearing deformation of the rubber layer. A rear wheel steering device for a vehicle, characterized in that the rear wheel steering device is configured to allow rotation of the rear wheel.