JPS6092902A - Centering device for wheel of self-steering axle - Google Patents

Abstract

PURPOSE:To aim at improvements in steering stability, by making up a device so as to give righting moment almost proportioned to a wheel's steering angle, to a wheel of a self-steering axle, in case of one that sets a rear axle down to the self-steering one in a car of rear two axles. CONSTITUTION:A control valve 21 operated by a cam on a sector shaft 12 is installed in a steering gearbox 7 controlled by a steering wheel 4 for turn-steering front wheels. An inlet port of the valve 21 is connected to an air tank 35 via a solenoid select valve 36, while an outlet port 24 is connected to a pair of symmetrical lock chamber 38 being attached to a self-steering axle 3 via a bracket 39. And, when a car speed to be detected by a speed censor 46 is low, the solenoid select valve 36 is opened, feeding the lock chamber 38 with air commensurate to a steering angle, thereby making it so as to give the specified righting moment to wheels 40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for restoring wheels on a Hilf steer shaft of an automobile, and more particularly to a restoring device for wheels on a self-steering shaft in which a restoring force is applied to the wheels on a self-steering shaft using an actuator. .

As automobiles become larger, the vehicle body also becomes larger. Therefore, the rear side of the vehicle body is supported by two axles on a platform where the vehicle weight is particularly large. In such a vehicle with two rear axles, the J5 uses the rear and front axles as drive shafts, and the rear and rear axles as self-steering axles. Therefore, while supporting the weight of the vehicle, the rear axle automatically performs steering action based on the forces received during driving.

In such a rear two-axle vehicle, if the self-steering action of the rear axle is not sufficient, uneven wear of the tie A7 will occur. Furthermore, if the restoring force of the wheels on the rear axle is not sufficient, the steering stability will deteriorate. In particular, in order to improve this steering stability, conventionally the caster angle was increased to increase the restoring force of the tie A7. However, if the caster angle is large, the shock applied to the tire during driving increases, and a damper with a large capacity must be provided to absorb this shock, which is a drawback. Furthermore, increasing the caster angle results in the disadvantage that the load that can be supported becomes smaller.

By the way, when driving at high speed, the d-3-C for a vehicle with two rear axles as mentioned above, controls the steering of the rear axle by U.
It is necessary to tsukutaru. For this purpose, conventionally, 7
When the vehicle speed exceeds a certain value, compressed air is supplied to the locking chamber to lock the rear axle. However, the locking lever described above only has the function of locking the wheels, and cannot provide a restoring force to the self-steering shaft.

Kizatmei was developed in view of these problems, and improves steering stability by giving the wheels of a self-steering shaft a restoring force that is approximately proportional to the turning angle of the steering wheel. The object of the present invention is to provide a wheel restoring device for a Relf steer shaft.

The present invention will be explained below with reference to an illustrated embodiment.

Figure 1 shows the restoration H of the wheels of the self-steering shaft according to this embodiment.
1 shows a bus equipped with an IFFI, the front end of which is supported by a front axle 1. On the other hand, the rear end of the vehicle body is
and the rear axle 3. The rear-front shaft 2 constitutes a drive shaft, and the rear-rear shaft 3 constitutes a self-steering shaft.

The wheels attached to the front axle 1 supporting the front end of the vehicle body are steered by a steering handle 4. The steering handle 4 is fixed to the steering shaft 5, and
The lower end of this shaft 5 is connected to a steering gear box 7 via a pair of joints 6, as shown in FIG.

The inside of the steering gear box 7 shown in FIG. 2 is as shown in FIGS. 3 d3 and 4, and a worm shaft 8 connected to the steering shaft 5 rotates. It is supported by its functionality. A pole tube 9 is attached to the outer peripheral surface of the worm shaft 8, and a pole 10 in the pole tube 9 is attached to the t-
It is designed to roll along the track. Further, a rack gear 11 is provided on the outer circumference of the pole duplex 9, and this rack gear A711 meshes with the sector gear 13 connected to the sector wheels 71-12.

A pitman arm 1 is attached to the end of the sector shaft 12.
4 is fixed. As shown in FIG. 2, the pitman arm 14 has its tip connected to a booster 16 via a connecting rod 15.

The booster 16 is further connected to a link lever 17, and the tip of the link lever 17 is connected to a drag ring 18. This drag ring 18 is connected to the knuckle of the front wheel via a knuckle arm (not shown). Further, the piston rod 19 of the booster 16 is fixed to the frame via an anchor bracket 20, as shown in FIG.

The steering gear box 7 is provided with a control valve 21 as shown in FIG.

The structure of this control valve 21 will be explained with reference to FIGS. 5 and 6. The valve 21 has a casing 22
The casing 22 has an inlet port 2.
3, an exit boat 24, and an exhaust boat 25 are formed, respectively. Also, inside the casing 22 is a piston 2.
6 is placed. The piston 26 is pushed upward by a main spring 29 interposed between a pair of upper and lower spring receivers 27 and 28. This main spring 29 is pushed by a plunger 30 via a lower spring receiver 28. The lower end of the plunger 30 is pushed by a cam 31 formed on the sector shaft 12 and consisting of a pair of protrusions. Further, a sleeve 32 is formed on the upper part of the piston 26, and the upper end of the sleeve 32 can come into contact with a valve body 33 disposed within the casing 22. The valve body 33 is pushed downward by a spring 34.

The inlet port 23 of this control valve 21 is connected to the second
As shown in the figure, an air tank 35 and an electromagnetic switching valve 36
It is designed to be connected via. Note that this electromagnetic switching valve 36 is connected to IA 5' of the vehicle speed detection sensor 1/46.
The output robot 24 of the control valve 21 is connected to a pair of left and right lock chambers 38 via a check valve 37. .This long mouth 1
The flap 38 is for providing a restoring force to the wheel 40 at the rear @3.

The pair of left and right lock chambers 38 are respectively attached to the rear shaft 3 via brackets 1 to 39. Wheels 40 are attached to both ends of the rear axle 3, respectively.

The knuckles 41 of the wheels/IO are rotatably supported by the rear shaft 3 via king pins 42, respectively.

A tie rod arm 43 is connected to the So-C sickle 41. A pair of left and right tie rod arms 43 are connected to H by a tie rod /I4.

The tie rod arms 43 on the left and right side of Mako are respectively compatible with the rod of Jru 1" Tsukubuyamba 38 and 3! l! The lock chamber 38 locks or provides a restoring force.

Next, the operation of the restoring device for the wheel 40 of the self-sdare shaft 3 having the above-described structure will be explained.

The electromagnetic switching valve 30 shown in FIG. 2 is switched to communicate the air tank 35 and the control valve 21 when the vehicle speed is low. That is, when the vehicle speed is below a predetermined value, the output of the sensor 46 is supplied to the controller 45, and the controller 45 switches the electromagnetic valve 36 to communicate with the control valve 21. Therefore, in this case, compressed air whose pressure has been adjusted through the control valve 21 passes through the check valve 37 and is supplied to the pair of left and right lock chambers 38 of the rear axle 3.

The inlet port 23 of the control valve 21 is supplied with primary pressure from the air tank 35 as shown in FIGS. 6 and 7, and the secondary pressure is applied to the locking chamber 38 through the outlet port 24. It has become. This pressure on the secondary side pushes the upper surface of the piston 26 disposed inside the casing 22. On the other hand, the lower side of the piston 26 is connected to the main spring 2
9 through the spring receiver ( ) 27.Furthermore, the F side of the main spring 29 is pushed by the cams 31 of the sectors (7) 1 to 12 through the plunger t730. The pressing force of 29 is determined by the slit of the cam 31 formed on the sector shaft 12.Moreover, this sector shaft 12
As shown in FIGS. 3 and 4, since the front wheel steering I configuration is configured, the force pushing the lower end of the piston 26 of the control valve 21 changes depending on the steering angle of the front wheels. It turns out.

Therefore, (when the steering angle is very small, that is, when the vehicle is traveling straight, the plunger 30 of the control valve 21 is moved by the cam 31 of the sector shaft 12, as shown in FIG. Therefore, the force of the spring 29 pushing the piston 26 is small.The pressure of the compressed air is applied to the upper side of the piston 26, and d3. The piston 26 moves upward when the force exerted by the spring 29 exceeds the force exerted by the compressed air by 1'', and its sleeve 32 comes into contact with the valve body 33 to close the valve 21. Therefore, in this case: The point at which the valve 21 starts the decompression operation IFO, that is, the pressure at which the valve body 33 is closed, becomes low, and therefore the pressure of the compressed air applied to the lock chamber 38 via the outlet boat 24 also becomes low. The restoring force applied to the wheel 40 is a small value.

On the other hand, when the steering handle 4 is rotated significantly to the right or left, the sector shaft 12 that constitutes the steering mechanism rotates to perform a steering operation for the front wheels, and the cams 31 of the sector shafts 71 to 12 rotate. Lower spring receiver 28 via plunge 1730
This will push up the The spring 29 is therefore compressed and pushes the piston 26 with a large force. Therefore, in this case, the secondary pressure of the compressed air applied to the upper side of the piston 26 becomes high, and the pressure for performing the decompression operation also increases accordingly. With such an operation, the pressure of the compressed air applied to the lock chamber 38 also increases, and the wheels 40 of the self-steering shaft 3 are subjected to an unnatural restoring force.

In this way, the wheels 10 of the self-steering shaft 3 of this embodiment receive a restoring force by the lock chamber 38, and the compressed air from the air tank 35 is supplied to the lock chamber 38. It is supplied via a control valve 21. Moreover, the control valve 21 is adapted to supply compressed air at a pressure corresponding to the rotation angle of the steering handle 4 to the lock chamber 38. Therefore, with this configuration, it is possible to apply a restoring force proportional to the turning angle of the steering handle 4 to the wheels 40 of the self-steering shaft 3. Therefore, J, using such a device,
Maneuvering stability can be improved.

Next, when a vehicle equipped with this restoring device travels at high speed, the speed of the vehicle is detected by the vehicle speed detection sensor 46. If the speed detected by the sensor 46 exceeds a predetermined value, the controller 45
A switching signal is supplied to the electromagnetic switching valve 36 by. Valve 36 is then switched to allow direct communication between air tank 35 and lock chamber 38. 1", that is, when running at high speed, compressed air is supplied to the lock chamber 38 of the controller 1 without passing through the roll valve 21, and the wheels 40 of the self-steering shaft 3 are locked. By movement,
The self-steering action of the wheels 40 of the self-steering shaft 3 at d3 is prevented during high-speed running, making it possible to achieve stable running. In this case, the check valve 37 is installed so that the compressed air that has passed through the electromagnetic valve 36 is not supplied to the control valve 21.
is now closed.

Although the present invention has been described above with reference to the illustrated embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the technical idea of the present invention. For example, the above-mentioned embodiment relates to a rear axle wheel restoring device consisting of a self-steering axle of a bus with two rear axles, but the present invention can also be applied to various other vehicles, for example, to a rear wheel rack of 21Nl. It is also an applicable iJ ability.

Further, in the above embodiment, the self-steering shaft 30 wheels 4
Although the actuator for applying restoring force to the cylinder 38 is composed of the hydraulic chamber 38, it is possible to use a hydraulic cylinder or other various actuators in place of the cylinder chamber 38. In addition, in the above embodiment J3, the roll valve 21 that is linked to the steering mechanism is installed in the steering gear A7 box 7, but the roll box 21 is removed from the steering gear A7 box 7. The position is not limited to this position and can be taken to other positions.

In the above-described invention, a control valve is provided which is linked to the steering mechanism, and the control valve is used to operate the steering mechanism. This invention relates to a restoring device for a wheel of a self-steering shaft, which supplies fluid pressure to the actuator according to the ring angle. Therefore, according to the present invention, there is no need to increase the caster angle of the wheels of the self-steering shaft, which reduces the impact load.
Furthermore, there is no need to provide a large-capacity damper to absorb impact loads. Furthermore, since the wheels receive a restoring force proportional to the turning angle of the steering wheel, steering stability is further improved.

[Brief explanation of drawings]

FIG. 1 is a side view of a bus equipped with a wheel restoration device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a self-steering shaft wheel restoration device installed in this bus. ,
Figure 3 is a sectional view showing the steering mechanism, and Figure 4 is a sectional view showing the steering mechanism.
The figure shows a sectional view taken along the line IV to IV, FIG. The figure is a sectional view similar to FIG. 6 when the steering wheel is rotated significantly. In addition, in the symbols used in the drawings, 3... Rear shaft (self-steering shaft) 4... Steering handle 7... Steering gear box 12... Sector shafts 71 to 21... Control valve 26. ...Piston 29...Main spring 30...Plunger 31...Cam (convex portion) 38...Lock chamber 40...Wheel. Applicant Hino Motors Co., Ltd. Ward C)

Claims (1)

[Claims] In a device in which a restoring force is applied to the wheels of a self-steering shaft by means of a non-steering wheel, a control valve is provided that interlocks with the steering wheel, and this control valve supplies fluid pressure according to the steering mm to the actuator in NO. A restoring device for a wheel of a self-steering shaft, characterized in that the wheel is restored.