KR20040102702A - A rear axle steering of a vehicle - Google Patents

Abstract

PURPOSE: A steering system of a rear wheel for a large vehicle is provided to improve travel stability by preventing understeer of the rear-wheel drive vehicle and minimizing radius of rotation in cornering. CONSTITUTION: A steering system comprises a steering wheel(100) steering a front wheel(108) for changing the direction of a vehicle, a steering gear unit(102) installed in the lower part of the steering wheel, a connecting arm(106) connected to the steering gear unit and tie rod arms(24,32) to steer the tie rod and a front axle(22), a first rear wheel steering unit(104) for mounting a connecting link to the steering gear unit, connecting an A-pipe and an E-pipe in the steering gear unit and installing B, C and D pipes for steering the rear wheel, and a second rear wheel steering unit(110) communicated with the first rear wheel steering unit and connected to the tire rod arm coupled to the rear axle for steering the rear wheel.

Description

Rear wheel steering system for large vehicles {A REAR AXLE STEERING OF A VEHICLE}

The present invention relates to a rear wheel steering device for a large vehicle, and more particularly, to a rear wheel steering device for a large vehicle for preventing understeer that the rear wheel drive vehicle has and minimizing a running rotation radius of the large vehicle.

In general, a steering device of a vehicle is a direction adjusting device for arbitrarily changing the driving direction of a vehicle, and includes a steering mechanism, a steering wheel, a steering shaft, a column, and a steering mechanism, and a steering gear, a link, and the like. It consists of a link mechanism consisting of a Pitman arm, a drag link, a tie rod, and the like.

In the vehicle having the above configuration, steering is performed on the front wheel by transferring the steering wheel movement amount to the front wheel when driving or changing lanes or turning. In general, the suspension and the steering device are the steering wheel of which the steering characteristics of the vehicle are generated on the rear wheel. If the centripetal force is large, it is designed to have Under Steer, a phenomenon in which the turning radius increases as the car moves outward.

As described above, the steering device of the vehicle changes the direction of the front wheel by interlocking the tie rods to the left or the right side according to the rotational direction of the gear installed at the end of the steering shaft, and recently, turning the steering force of the steering wheel according to the speed of the vehicle. It is difficult to maintain the stability of the body when steering at high speeds. In recent years, four-wheel steering systems that can steer the front and rear wheels at the same time have been developed. It was a steering system that could only be applied to vehicles.

In addition, most commercial vehicles are provided with two rear axles to effectively share the weight of the loading compartment. Such rear axle two-wheeled vehicles have a leaf spring method supporting two axes simultaneously and a separate leaf spring supporting each axle independently. There was a way.

However, since the rear two-wheeled commercial vehicle receives a lot of grounding resistance from the road surface when the curve turns, the amount of wear of the tire increases, and the turning radius increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a rear wheel steering apparatus for a large vehicle that prevents the understeer phenomenon of the rear wheel drive vehicle.

In addition, an object of the present invention is to provide a rear wheel steering apparatus for a large vehicle that improves driving stability by minimizing a rotation radius when curving a large vehicle.

1 is a state diagram showing a state in which the rear wheel steering apparatus of the large vehicle of the present invention is neutral.

Figure 2 is a state diagram showing the state when the rear wheel steering apparatus of the large vehicle of the present invention left turn

Figure 3 is a state diagram showing a state when the rear wheel steering apparatus of a large vehicle of the present invention is a right turn

Figure 4 is an enlarged view showing the configuration of the first rear wheel steering unit of the present invention

* Explanation of symbols for the main parts of the drawings

10: connection link 12,28: piston rod

14: first actuator 16: directional control valve

18,19: pressure control valve 20: bidirectional check valve

22: front wheel shaft 24,32: tie rod arm

26,34: tie rod 28: 2nd actuator

30: second actuator 36: rear wheel shaft

38: recess 40: buffer member

100: steering wheel 102: steering gear

104: first rear wheel steering unit 106: connecting arm

108: front wheel 110: second rear wheel steering unit

112: rear wheel

A: pipeline A B: pipeline B

C: pipeline C D: pipeline D

A1: first chamber B1: second chamber

C1: third chamber D1: fourth chamber

The present invention for achieving the above object is a steering wheel for steering the front wheel to change the direction of the vehicle, a steering gear unit is installed on the lower side of the steering handle, the steering gear unit is connected to the tie rod arm and A steering apparatus comprising a connecting arm connected to a tie rod and a front wheel shaft to be connected, wherein a connecting link is provided at the steering gear, a pipe A and a pipe E are installed at the steering gear, and the pipe A and the pipe E are connected to each other. A first rear wheel steering unit connected to the pipe line B, the pipe line C, and the pipe line D for steering the rear wheels; And a second rear wheel steering unit installed to communicate with the first rear wheel steering unit and connected to a tie rod arm connected to the rear wheel shaft to steer the rear wheel.

Each of the first rear wheel steering units includes a chamber, a pipe line A, a pipe line B, a pipe line C, a pipe line D, a pipe line E connected to the chamber, and a buffer member is provided in the chamber. A first actuator having a piston rod operatively connected to the connection link; A pressure control valve connecting a pipe line B and a pipe line D connected from the first actuator; And a bidirectional check valve installed in parallel with the pressure control valve and connecting the pipe line B and the pipe line D. The direction control valve is installed under the first actuator to control the direction of the piston rod. And a concave portion is formed in an intermediate portion of the piston rod, and a direction control valve is connected to the concave portion.

The second rear wheel steering unit may include: a second actuator having a plurality of chambers formed therein and having a conduit B, a conduit C, and a conduit D respectively connected to the chambers; And a piston rod installed in connection with a tie rod arm to move back and forth by the operating fluid flowing into the conduit and to move the rear wheel, and having an automatic adjustment lever inside the second actuator. It is done.

Preferred embodiments of the present invention as described above will be described in detail with reference to the accompanying drawings.

1 is a state diagram showing a state in which the rear wheel steering apparatus of the large vehicle of the present invention is neutral, Figure 2 is a state diagram showing a state when the rear wheel steering apparatus of the large vehicle of the present invention is left turn, Figure 3 is 4 is an enlarged view showing the configuration of the first rear wheel steering unit of the present invention.

First, referring to Figures 1 to 4, the large vehicle rear wheel steering device of the present invention is a steering wheel 100 for switching the direction of the vehicle, and the steering gear unit 102 in the lower portion of the steering wheel (100) The connection is installed.

Since the steering gear unit 102 uses a gear unit of a vehicle that is commonly used, a detailed description thereof will not be provided.

One side of the lower end of the steering gear unit 102 is provided with a connection link (10).

In addition, the steering gear unit 102 is connected to the pipeline A (A) and the pipeline E (E), respectively, so that the working fluid flows as the steering handle 100 rotates.

The connecting link 10 is connected to the piston rod 12 of the first rear wheel steering unit 104.

A recess 38 is formed in the piston rod 12, and a push bar of a direction control valve 16, which will be described later, is positioned in the recess 38 to be mechanically operated. That is, when the front wheel and the rear wheel are aligned, the push bar is positioned in the concave portion 38 of the piston rod 12, and the pipe A is connected to the pipe in the direction of the arrow by the elasticity of the spring installed in the direction control valve 16. A), pipeline B (B) and pipeline C (C) communicate with each other.

When the front wheel and the rear wheel are steered, the piston rod 12 moves forward and backward to push the push bar of the direction control valve 16 so that the left and right pipes of the direction control valve 16 are blocked, and according to the pipe lines A, B and C. Steer independently.

The connecting link 10 rotates the steering handle 100 to operate the steering gear unit 102 to pull or push the connecting link 10 and at the same time connect the pipeline A (A) and the pipeline E (E). It is installed to choose.

The first rear wheel steering unit 104 has a piston rod 12 and is installed on one side of the first actuator 14 operated by the fluid power source and the first actuator 14 to control the flow of the fluid power source. The directional control valve 16 and the respective pipe lines A, B, C, D, and E connected to the first actuator 14, and the pipe line B (A) and the pipe line of the respective pipe lines. Pressure control valves 18 and 19 connecting D (D) and bidirectional check valves 20 connecting pipe B (B) and pipe D (D) at regular intervals from the pressure control valves 18 and 19. It consists of).

The first actuator 14 is composed of five first, second, third, fourth, fifth chambers A1, B1, C1, D1, E1, and each of the chambers A1, B1, C1, D1, E1. Each of the pipelines A, B, C, D, and E is correspondingly connected to each other. That is, the pipe line A (A) is connected to the first chamber A1, the pipe line B (B) is connected to the second chamber B1, and the pipe line C (C) is connected to the third chamber C1. The pipeline D (D) is connected to the fourth chamber D, and the pipeline E (E) is connected to the fifth chamber E1.

Each of the pipes connected as described above is the fluid fluid is pressed by the forward and backward operation of the piston rod 12 by the rotation operation of the steering wheel to move through the pipe.

The power fluid uses hydraulic oil or air pressure.

A direction control valve 16 is disposed below the piston rod 12 at a lower portion of the first actuator 14 and the third chamber C1.

A semi-circular recess 38 is formed at a portion where the piston rod 12 and the directional control valve 16 are connected, and a general push is provided at the recess 38 in the directional control valve 16. It is equipped with a bar.

On the other hand, a connecting arm 106 is connected to the connecting link 10 connected to the steering gear unit 102, and the connecting arm 106 is synchronized when the connecting link 10 moves as the steering gear unit 102 operates. To move.

The connecting arm 106 is connected to the tie rod arm 24.

The front wheel 108 of the vehicle consists of a pair of left and right, and the pair of left and right front wheels 108 are connected by the front wheel shaft 22.

A tie rod arm 24 is fixedly connected to both ends of the front wheel shaft 22, and a tie rod 26 is connected to the tie rod arm 24.

As the tie rod arm 24 and the tie rod 26 move the connection link 10 by the operation of the steering gear unit 102 and the connection arm 106 connected to the connection link 10 operates. Link operation.

Subsequently, the conduits A, B, C, and D connected at the first actuator 14 of the first rear wheel steering unit 104 are connected to the second rear wheel steering unit 110 for steering the rear wheel 112. It is.

The second rear wheel steering unit 110 includes a second actuator 30 having an automatic adjustment lever V and a piston rod 28.

The second actuator 30 is composed of first, second, third and fourth chambers W, X, Y, and Z, and is connected to the pipe lines B, C, and D.

More specifically, the pipe line B (B) is connected to the second chamber (X), the pipe line C (C) is branched and connected to the third chamber (Y) and the fourth chamber (Z), Pipeline D (D) is connected to the first chamber (W).

The buffer member 40 is disposed between the third chamber Y and the fourth chamber Z. The shock absorbing member 40 prevents vibration, shock, and the like, which are generated when the piston rod 28 proceeds rapidly when the piston rod 28 moves forward and backward.

Hereinafter, the operation and operation of the rear wheel steering apparatus of the present invention will be described.

First, in order to align the wheels in parallel by the steering wheel 100 in the vehicle in a straight line, the connecting link 10 connected to the first actuator 14 of the first rear wheel steering unit 104 is clockwise in a vertical direction. It is inclined about 15 degrees and positioned as shown in Fig. 1, in which case it remains neutral.

In the case of maintaining the neutral as described above, the piston rod 12 of the first actuator 14 is connected to the second chamber (B1) and the fourth chamber (D1) through the directional control valve 16 to equalize the pressure. And the operating fluid of the third chamber C1 is connected to the third chamber Y and the fourth chamber Z of the second hydraulic actuator 30 of the second rear wheel steering unit 110 through the pipe line C (C). To communicate with each other to create an even pressure.

On the other hand, the pipeline B (B) and the pipeline D (D) is in communication with the first chamber (W) and the second chamber (X) of the second actuator 30, the piston rod 28 of the second actuator (30) Maintains neutral so that the tie rod arm 32 of the rear wheel 112 keeps the tie rod 34 parallel to the rear wheel shaft 36 to align the rear wheel 112 with the front wheel 108, Maintain neutrality to stay straight.

In addition, when the rear wheel 112 is to be steered to the right, when the steering wheel 100 is rotated to the right, the link link 10 further proceeds clockwise to push the piston rod 12 of the first actuator 14. .

At the same time, the connecting arm 106 is also pushed to move the tie rod arm 24 connected to the front wheel 22 and to rotate the front wheel 22 by moving the tie rod 26.

At this time, the working fluid flows through the pipeline A (A) to flow into the first chamber A1, and pushes the piston rod 12 of the first actuator 14 to the second chamber B1 and the neutral at the time of neutralization. The four chambers D1 are blocked from each other, and the working fluid of the fourth chamber D1 is filled and introduced into the first chamber W of the second actuator 30 through the pipe line D (D) to open the piston rod 28. As shown in the arrow direction of FIG. 2, the rear wheel 112 is rotated clockwise, that is, as shown in FIG. 2 by pushing the tie rod 34 while pushing the tie rod arm 32 connected to the rear wheel shaft 36 at the same time. Steer to turn left and turn right.

As described above, when the front wheel rotates right, the rear wheel 112 is steered at the same time so that the rotation radius is reduced and understeer is prevented.

Subsequently, when the rear wheel 112 is to be steered to the left, when the steering wheel 100 is rotated to the left, the link link 10 is pulled counterclockwise to pull the piston rod 12 of the first actuator 14. do.

At the same time, the connecting arm 106 is also pulled to move the tie rod arm 24 connected to the front wheel 22 and move the tie rod 26 to rotate the front wheel 22 to the left.

At this time, the working fluid flows through the pipe line E (E) to flow into the fifth chamber E1, and pushes the piston rod 12 of the first actuator 14 to the working fluid through the pipe line B (B). Filled into the second chamber X of the two actuators 30, the piston rod 28 is pushed up to all as shown in the arrow direction of FIG. 3 to push up the tie rod arm 32 connected to the rear axle 36. At the same time, by pushing the tie rod 34, the rear wheel 112 is turned counterclockwise, that is, steering to be inclined to the right as shown in FIG.

As described above, when the front wheel rotates left, the rear wheel 112 is steered in the left turning direction at the same time, thereby reducing the rotation radius and preventing the understeer.

In addition, the present invention as described above is not limited to the specific embodiments described above, and anyone skilled in the art to which the invention belongs without departing from the gist of the invention claimed in the claims various modifications Would be possible.

The rear wheel steering apparatus of a large vehicle of the present invention as described above is to install a separate link to the existing vehicle steering device and to install the first and second actuators to select the respective pipes by the steering wheel steering device to steer the rear wheels As a result, it is possible to prevent understeering that occurs during cornering driving that all rear wheel vehicles have, and has the advantage of ensuring the driving stability performance of the vehicle at the time of curved turning track to the maximum, and thereby the vehicle safety of the curved road. There is an effect to reduce the accident, it is effective to minimize the radius of rotation of the vehicle.

Claims (6)

A steering wheel for steering the front wheels to change the direction of the vehicle, a steering gear unit installed under the steering wheel, a connecting arm connected to the steering gear unit and connected to a tie rod arm to steer the tie rod and the front wheel shaft. In the steering device consisting of, A connecting link is installed in the steering gear unit, a pipe line A and a pipe line E are installed in the steering gear part, and the pipe line A and the pipe line E are connected to each other, and the pipe line B, the pipe line C, and the pipe line D are connected to each other to steer the rear wheels. A first rear wheel steering unit; And a second rear wheel steering unit installed to communicate with the first rear wheel steering unit, the second rear wheel steering unit being connected to a tie rod arm connected to the rear wheel shaft to steer the rear wheel. The method of claim 1, The first rear wheel steering unit has a chamber formed therein, and includes a pipe line A, a pipe line B, a pipe line C, a pipe line D, a pipe line E connected to the chamber, respectively, and the buffer member is provided in the chamber. A first actuator having a piston rod operatively connected to the connecting link; A pressure control valve connecting a pipe line B and a pipe line D connected from the first actuator; And a bidirectional check valve installed in parallel with the pressure control valve and connecting the pipe B and the pipe D. The method of claim 2, The rear wheel steering apparatus for a large vehicle, characterized in that it is provided in the lower portion of the first actuator to control the direction of the piston rod. The method of claim 2, A recess is formed in the middle portion of the piston rod, the rear wheel steering apparatus for a large vehicle, characterized in that the directional control valve is connected to the recess. The method of claim 1, The second rear wheel steering unit includes: a second actuator having a plurality of chambers formed therein and having a conduit B, a conduit C, and a conduit D respectively connected to the chambers; And a piston rod installed in connection with a tie rod arm to move back and forth by a working fluid flowing into the conduit and to move the rear wheel. The method of claim 5, Rear wheel steering device for a large vehicle, characterized in that the automatic adjustment lever is provided inside the second actuator.