JPH04116285U - Rear wheel steering device for trucks, etc. - Google Patents

Abstract

(57) [Summary] (with amendments) [Purpose] To improve the steering stability of vehicles equipped with a rigid rear axle housing during high-speed driving, to reduce the size and weight of the rear wheel steering actuator, and to further improve the minimum ground clearance. Ensure high. [Structure] The rear end of an upper radius rod 2b having a V-shaped planar shape is pivotally attached to the upper surface of the rear axle housing 1b, and the front ends of both legs of the rod are attached to the chassis frame 1.
Pivot to 0. Further, the rear end of a bar-shaped lower radius rod 34 is pivotally connected to the front portion of the lower surface of the casing, and the front end of the rod is pivotally connected to the chassis frame 10, so that the upper radius rod 26 and the lower radius rod 34
are arranged so that they form a parallel link mechanism. Furthermore, rear wheel steering actuators 5 are provided at both ends of the housing.
6 are connected, and when the front wheels are steered during high-speed running, the left and right rear wheel steering actuators 56 are operated in opposite directions to slightly rotate the steering angle.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a rear wheel steering device for a truck or the like.

0002

[Conventional technology]

In order to improve steering stability when the vehicle is running at high speeds, it is linked to the steering of the front wheels. Various four-wheel steering systems and devices have been proposed in which the rear wheels are steered by . However, conventional four-wheel steering systems are not suitable for vehicles where the front and rear wheels are independently suspended. The rear wheel is supported by a rigid axle tube or rear axle housing. Four-wheel steering systems for vehicles such as trucks, especially those with double tires on the rear wheels. No location has been proposed yet.

0003

[Problem that the idea aims to solve]

This invention is based on a truck in which the rear wheels are supported by both ends of the rear axle housing in the vehicle width direction. Improves steering stability during high-speed running on racks, etc., and is small and lightweight. Provides a rear wheel steering device that enables rear wheel steering using an actuator. The purpose is to

0004

[Means to solve the problem]

This invention was devised to achieve the above purpose, and is It supports the rear wheels and is suspended on the chassis frame via a suspension spring device. The rear axle housing is located along the center line in the longitudinal direction of the vehicle body, and its apex is The differential gear installed in the center of the rear axle housing in the width direction of the vehicle. The free ends of both legs are attached to the chassis frame. The upper radius rod has a V-shaped planar shape, and the center radius rod in the longitudinal direction of the vehicle body. It is placed below the above-mentioned upper radius rod along the core wire, and one end of it is placed below the above-mentioned differential rod. On the lower surface of the differential casing, before the pivot point of the above upper radius rod. a rod-shaped lower radiator whose other end is pivotally connected to the chassis frame; The asrod is mounted on the above chassis frame and the respective output ends are connected to the above rear axle handle. It is pivoted on both sides of the Uzing's center line in the longitudinal direction of the vehicle body, and is When the rear axle housing is steered, the rear axle housing is pivoted to the upper radius rod. A pair of rear wheel steering actuators that rotate around a vertical steering axis that passes through the center of arrival. This invention proposes a rear wheel steering device for trucks, etc., characterized by being equipped with a be.

[0005]

[Effect]

According to the present invention, the rear axle housing supports the rear wheels at both ends in the vehicle width direction. The upper and lower surfaces of the differential casing are V-shaped upper radii that are pivotally connected at one end to each other and cooperate to form a substantially parallel link mechanism. It is connected to the chassis frame via an ass rod and a bar-shaped lower radius rod. Therefore, while the above-mentioned upper radius rod is pivoted on the top surface of the differential casing, It can rotate around a longitudinal steering axis passing through the center. Also the lower radia above the upper radius rod on the top surface of the differential casing. By pivoting to the lower surface of the part in front of the pivot point, a reduction in minimum ground clearance can be avoided. can be done. Both sides of the center line in the longitudinal direction of the vehicle body of the above rear axle housing In other words, the output ends of a pair of rear wheel steering actuators are connected at approximately symmetrical positions, and the The above pair of actuators operate in opposite directions during steering during high-speed driving. By this, the rear axle housing rotates around the above-mentioned longitudinal axis and steers the vehicle. do. The rear axle housing has its upper and lower surfaces at the center in the vehicle width direction. Connected to the chassis frame by the upper radius rod and lower radius rod. Because of this, the windup torque during sudden starts and sudden braking is transferred to the upper radius rod. Therefore, it is supported and has almost no effect on the rear wheel steering actuator, so the actuator The data can be made small and lightweight.

[0006]

【Example】

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The code 10 in the figure is A chassis frame of a vehicle such as a rack, which has a pair of left and right sides that extend in the front and back direction of the vehicle body. The rail 12 extends in the width direction of the vehicle and has both ends fixed to the left and right side rails 12. It is composed of a plurality of cross members 14. 16 are both ends in the width direction Rigid rear axle housing supporting double tires 18, 20 is the same rear Fixing devices such as U bolts 22 are attached to the upper side of the axle housing 16 near both ends in the vehicle width direction. 24 is the above-mentioned spring support member having a hat-shaped side surface attached to the spring support member. The above-mentioned springs are arranged in front and behind the end of the rear axle housing 16 and sandwich the end of the rear axle housing 16. The self-circumference interposed between the support member 20 and the side rail 12 of the chassis frame 10 It is an air spring of knowledge. 26 is arranged along the center line of the chassis frame 10 in the longitudinal direction of the vehicle body and has a planar shape. is a V-shaped upper radius rod, and the apex of the radius rod is a bow. The above-mentioned link can be connected via the rubber bush type joint device 28 or the equivalent rubber bush type joint device. Differential casing provided in the center of the axle housing 16 The free ends of both legs of the rod are pivoted to the upper surface of the rod 30, and the free ends of both legs of the rod are connected to ball joints, respectively. The chassis frame 1 is connected to the chassis frame 1 via the joint device 32 or a rubber bush type joint device with the same effect. It is pivotally attached to the side rail 12 of 0. Below the upper radius rod 26 A rod-shaped lower radius rod 34 is provided, one end of which is fitted with a rubber bushing type jaw. Pivotally attached to the lower surface of the differential casing 30 via an insert device 36 and the other end of the rod 34 is connected to a ball joint device 38 or equivalent rubber. Fixed to the cross member 14 of the chassis frame 10 via a bush type joint device The bracket 40 is connected to a Diff the lower radius rod 34 above. The rubber bush type joint device 36 that is pivotally connected to the differential casing 30 is A ball pivotally connects the upper radius rod 26 to the differential casing 30. The joint device 28 is located in front of the vehicle body. This is well shown in Figure 2. As shown, the differential casing 30 has a funnel-shaped shape that converges toward the front of the vehicle body. , the joint device 36 of the lower radius rod 26 is connected to the upper radius rod. Reduced minimum ground clearance compared to when placed directly below the joint device 28 of the joint can be avoided. Also, as shown in Figure 2, the upper radius rod 26 and the lower radius rod 34 constitute a substantially parallel link mechanism in the vertical plane. It is set up so that

[0007] In particular, as shown well in FIG. 2, the width of the rear axle housing 16 A bracket 42 is provided along with the spring support member 20 on the lower surface near both ends in the direction. They are fastened together with U bolts 22, and the same bracket 42 has a ball joint. A pair of left and right actuation locks are connected via the device 44 or a rubber bush type joint device with the same effect. One end of the door 46 is pivotally mounted. The other end of each actuating rod 46 is connected to the side rail. It is pivoted by a pin 50 to a bracket 48 fixed to the web or side wall of 12. The actuating levers 52 are pivotally connected to the lower ends of the actuating levers 52 by pins 54, respectively. Furthermore, the above work At the upper end of the dynamic lever 52, there is a hydraulic system that forms a pair of left and right rear wheel steering actuators. A piston shaft 58 of the cylinder device 56 is pivotally connected by a pin 60, and the actuator The cylinder 62 of the motor is connected to the web or side of the side rail 12 by means of a pin 64. It is pivoted to the wall.

[0008] An example of a specific configuration of the ball joint devices 28, 32, and 38 is shown in FIG. has been done. In the same figure, reference numeral 66 indicates one of the members that rotates relative to each other, that is, the above-mentioned upper member. The radius rod 26, lower radius rod 34 or actuation rod 46 is shown, and 68 is Attachment of the other member, that is, the differential casing 30 and the chassis frame 10 A bracket or said bracket 42 is shown. The spherical member 7 is attached to the other member 68. A shaft 72 having a diameter of A contacting ball seat 74 is supported. With this configuration, one member 66 is a plane perpendicular to the axis of the shaft 72 and a plane including the coaxial line with respect to the other member 68 They can each rotate relative to each other. In addition, FIG. 5 shows a rubber bushing that is functionally almost the same as the ball joint device described above. A type joint device is shown. One member 76 similar to FIG. 4, e.g. The lower radius rod 26, the lower radius rod 34 or the actuation rod 46 are shown; 8 is the other member, namely the differential casing 30 and the chassis frame 10. The mounting bracket or bracket 42 is shown. The end of the one member 76 A rubber bush 80 is fixed by baking to the inner circumference of the rubber bush 80. 82 are baked and fixed at the same time. The spherical member 82 is supported by the other member 78. A held pivot shaft 84 is inserted therethrough. With this configuration, one member 76 and the other 78 in a plane perpendicular to the axis of the pivot 84 and in a plane including the axis. Not only is relative rotation allowed, but the bending of the rubber bushing 80 allows rotation of the pivot shaft 84. On the other hand, one member 76 is allowed to be relatively displaced in the left-right direction in the figure.

[0009] Next, FIG. 6 shows a conceptual diagram of a control device for operating the rear wheel steering actuator 56. FIG. Reference numeral 86 in the figure is inserted into the steering shaft 88 to control the steering angle. For example, a light pulse non-contact type steering angle sensor is used for detection, 90 is a vehicle speed sensor, and 92 is a steering angle sensor. 94 is a steering angle signal from a steering angle sensor 86 and a vehicle speed from a vehicle speed sensor 90. The rear wheel steering actuator 5 receives the signal and the turning signal of the yaw rate sensor 92. 98 is a hydraulic pump. In this control device, when the vehicle is traveling at high speed, the steering link wheel When the wheel 100 is operated and the front wheels 102 are steered, the steering angle signal from the steering angle sensor 86 is The controller receives the vehicle speed signal from the vehicle speed sensor 90 and the turning signal from the yaw rate sensor 92. The controller 94 issues a drive signal to the control valve 96 to operate the control valve. control valve The high-pressure hydraulic oil discharged from the hydraulic pump 98 by the operation of 96 is applied to a pair of steering actuators. is supplied to the actuator 56, and the actuator 56 moves in the opposite direction, i.e. so that when one actuator extends, the other actuator contracts. Operate. Steering the rear wheels to improve steering stability when the vehicle is running at high speeds. In this case, normally the rear wheels 18 are steered by a small steering angle in the same direction as the front wheels 102, for example, from 1 to 5. It is steered to a certain degree. However, in connection with the steering of the front wheels 102, the steering of the front wheels 102 is initially The rear wheels 18 are steered by a slight angle in the direction opposite to the steering direction, and after an instant, the rear wheels 18 are turned to the front wheels 1. Other rear wheel steering systems, such as a slight angle steering in the same direction as the 02 steering direction, are adopted. It is also possible to

0010 In the above configuration, the hydraulic cylinder device 56 forming the rear wheel steering actuator The cylinder 62 has a stroke that limits the extension and retraction strokes of the piston shaft 58. A built-in stopper prevents the rear actuator from operating when the hydraulic cylinder device 56 is activated. The steering wheel housing 16, that is, the rear wheel 18, has a preset slight steering angle of 1 to 5 degrees, for example, 1 degree. The hydraulic cylinder device 56 When at rest, it is locked by the actuation of a built-in neutral spring or hydraulically (the piston The piston is fixed in the neutral position by applying equal hydraulic pressure to both chambers of the piston. Therefore, the piston shaft 58 is fixed at the neutral position, and the rear axle housing 16 is immediately In other words, the rear wheels 18 are maintained in a straight-ahead state with zero steering angle. When the front wheels 102 are steered while the vehicle is running at high speed, the controller The control valve 96 is activated by the command 94, and the pair of rear wheel steering actuators 56 are activated. As shown in the schematic diagram of Figure 3 by solid line arrows and dotted line arrows, move. An actuation lever whose one end is connected to the piston shaft 58 of each actuator. -52 rotate in opposite directions, and an actuator connected to the other end of one of the actuating levers 52 rotates in opposite directions. The actuating rod 46, which is the output end of the tuator, is pulled toward the front of the vehicle, and the other actuating lever An operating rod 46 connected to the other end of 52 is driven toward the rear of the vehicle body. This results in The lower axle housing 16 is installed at the top of the V-shaped upper radius rod 26. The vertical steering axis O-O passing through the center of the tilted ball joint device 28 (Fig. 2 (Reference)) The steering angle can be set by rotating the steering angle by one degree, for example, in either the left or right direction. As a result, the steering stability at high speeds is improved in a manner well known in the art. child When the lower radius rod 34 is attached to the bottom surface of the differential casing 30 Since they are connected by a bush type joint device 36, the joint device 36 is located away from the steering axis O-O to the front of the vehicle body. However, due to the elastic deformation of the rubber bush 80, the rear axle housing 16 Steering at a small angle is performed smoothly. The rotation of the rear axle housing 16 around the steering axis O-O is not shown in the figure. In the case of the embodiment, since the suspension spring is the air spring 24, The rubber diaphragm 104 (see Fig. 2) bends freely in the horizontal direction. The process is extremely smooth. Also, a suspension can be used instead of the air spring 24 mentioned above. When a leaf spring is used as a spring, the leaf spring and A rubber pad or the like is interposed between the rear axle housing 16 and the leaf spring. When the rear axle housing 16 What is necessary is just to configure it so that it can be relatively displaced. In addition, it is possible to prevent damage to the undercarriage frame 10 that occurs while the vehicle is traveling straight or while turning during steering. The vertical movement of the rear axle housing 16 is caused by the air spring 24 receiving the load. At this time, the rear axle housing 16 is placed in the upper radius slot. Parallel link movement is performed up and down by the rod 26 and the lower radius rod 34. Furthermore , the upper radius rod 26 and the lower radius rod 34 are each a ball joint. The rear Since it is pivotally connected to the axle housing 16 and the chassis frame 10, it can be easily used on uneven roads. When traveling or turning, left and right tilting of the rear axle housing 16 is prevented. Never. Furthermore, the rear axle housing 16 is connected to the upper radius rod 26 and the lower radius rod 26. Since it is connected to the chassis frame 10 by the radius rod 34, sudden starts and The windup torque that occurs during braking and sudden braking is applied to the upper radius rod 26 and the lower radius rod 26. It is largely carried by the radius rod 34. Therefore, the rear wheel steering actuator The motor 56 is a small and lightweight hydraulic cylinder with virtually no wind-up torque acting on it. device can be safely employed. In addition, the lower radius rod 34 is steered. Differential casing 3 of the rear axle housing in front of the axis O-O Since it is pivoted on the bottom surface of the steering wheel, the lowest ground position is lower than when it is pivoted on the steering axis O-O. It is possible to avoid a decrease in upside. In addition, in the above embodiment, a vehicle with one rear axle is illustrated, but a vehicle with two rear axles is used. In both cases, the same rear wheel steering device as above is provided on both the rear front axle and the rear rear axle. Ru. In addition, in vehicles with two rear axles, one of the rear axles is often a dead axle that does not transmit driving force. However, the steering device itself is substantially the same as the drive wheel case described above. It is.

[0011]

[Effect of the idea]

As mentioned above, the rear wheel steering device for trucks, etc. according to the present invention has a It supports the rear wheels and is suspended on the chassis frame via a suspension spring device. The rear axle housing is arranged along the center line in the longitudinal direction of the vehicle and its apex The differential installed in the center part of the rear axle housing in the vehicle width direction. The free ends of both legs are pivotally connected to the top surface of the chassis frame, and the free ends of both legs are attached to the chassis frame. The upper radius rod is pivotally connected and has a V-shaped planar shape, and the It is placed below the upper radius rod along the center line and has one end connected to the radius rod. From the pivot point of the above upper radius rod on the bottom surface of the ferential casing. A rod-shaped lower lever is pivotally connected to the front position and the other end is pivotally connected to the chassis frame. The geos rod is mounted on the above chassis frame and the respective output ends are connected to the above rear axle. The housing is pivotally mounted on both sides of the center line in the longitudinal direction of the vehicle body, and is used when the vehicle is running at high speed. When the rear axle housing is steered, it moves the rear axle housing to the upper radius rod. A pair of rear wheel steering actuators that rotate around a vertical steering axis that passes through the pivot center. a rigid rear axle tube, i.e., a rear axle housing. This improves the steering stability of trucks, etc. equipped with , and achieved a reduction in the size and weight of the rear wheel steering actuator, while at the same time reducing the minimum ground clearance. This is useful in practice since it is possible to avoid the decrease.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a side view of the rear wheel steering device shown in FIG. 1.

3 is a schematic plan view of the rear wheel steering device shown in FIG. 1. FIG.

4 is a sectional view showing an example of a ball joint device in the rear wheel steering device shown in FIG. 1. FIG.

5 is a sectional view showing a rubber bush type joint device in the rear wheel steering device shown in FIG. 1. FIG.

6 is a schematic configuration diagram of an operation control device for a rear wheel steering actuator in FIG. 1. FIG.

[Explanation of symbols]

10 Chassis frame 16 Rear axle housing 18 Rear wheel 26 Upper radius rod 34 Lower radius rod 56 Rear wheel steering actuator

Claims (1)

[Scope of utility model registration request] 1. A rear axle housing that supports a rear wheel at both ends in the vehicle width direction and is suspended from a chassis frame via a suspension spring device, and a rear axle housing that is disposed along a longitudinal center line of the vehicle body and whose apex is connected to the rear axle housing. An upper radius rod having a V-shaped planar shape, which is pivotally connected to the upper surface of the differential casing provided at the center portion of the housing in the vehicle width direction, and whose free ends of both legs are pivotally connected to the chassis frame, respectively; The upper radius rod is disposed below the upper radius rod along the center line of the direction, and one end thereof is pivotally connected to a position forward of the pivot point of the upper radius rod on the lower surface of the differential casing, and the other end is pivotally connected to the chassis frame. A bar-shaped lower radius rod is mounted on the chassis frame, and its output ends are pivotally connected to positions on both sides of the center line in the vehicle longitudinal direction of the rear axle housing. A rear wheel steering device for a truck or the like, comprising a pair of rear wheel steering actuators that rotate a rear axle housing around a vertical steering axis passing through the pivot center of the upper radius rod.