JPH0580944U - Traction control device for multi-axle vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a traction control device for a multi-axle vehicle that can achieve both anti-lock braking and traction control with a small number of channels. [Structure] Valves 6a and 6b are respectively inserted in the hydraulic pressure paths from the air master cylinders 5R and 5L to the wheel cylinder 35 side of the driven shaft 2. Then, the left and right hydraulic pressure paths 81
The valves inserted in the R and 81L are integrally connected to form a balance valve 6. The balance valve 6 is provided with a balance piston 6c that slides by the hydraulic pressures of the left and right hydraulic pressure passages 81R and 81L, and is configured to close the hydraulic pressure passage 81 on the left or right side where the hydraulic pressure is high. As a result, dragging of the driven wheels can be prevented and the brake balance of the left and right wheels can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a traction control device for a multi-axle vehicle, and more particularly to a traction control device having an air-over hydraulic brake and an antilock brake.

[0002]

[Prior Art]

 Some large vehicles have one front axle and two rear axles to distribute the load. In recent years, anti-lock brakes have tended to be installed in this type of multi-axle vehicle, but it is desirable to install a traction control device together to prevent slipping of the drive wheels when starting.

An example of such a multi-axle vehicle provided with an anti-lock brake and a traction control is shown in FIG. In the signal lines in the figure, the thin diagonal line represents the signal pneumatic system, the thick diagonal line represents the working pneumatic system, and the non-shaded line represents the hydraulic system. Although the pneumatic pressure source is omitted, the pneumatic pressure input is indicated by arrow A.

The brake valve 100 controls the air pressure from the air pressure input A and supplies air pressure corresponding to the brake operation amount to the two relay valves 101 and 101 a. The air pressure from the relay valve 101 is controlled by the brake valve 100. The pressure is applied to the rear wheel air master cylinder 104 via the two-way valve 103 and the air control valve 102.

Air pressure from the relay valve 101a is applied to the front wheel air master cylinder 104a via the air control valve 102a. Then, the air pressure is converted into hydraulic pressure by the air master cylinders 104, 104a and distributed to each wheel cylinder WC. A rotation sensor S is provided on the front wheel F and the drive wheel M. The two-way valve 103 is for comparing the air pressure from the relay valve 101 and the air pressure from the valve 3 and supplying the higher air pressure to the air master cylinder 104.

The air control valve 102 and the rotation sensor S are connected to an ECU 200 (central control unit), and a signal from the ECU 200 opens and closes the air conditioning control valve 102 to prevent the wheels from being locked. ing.

That is, when the wheel locks, the rotation speed of the rotation sensor S drops, and the ECU detects this to control the pressure in the air master cylinder 104 by the air control valve 102 so that the wheel does not remain locked. Is becoming

The above is the general structure of the air-over-hydraulic brake, but a traction control device is provided in addition to the above structure. That is, the ECU 200 detects the excessive rotation state of the drive wheel M, and opens the traction control valve 3 provided in the working pneumatic system to supply pneumatic pressure to the air master cylinder 104 so as to supply the rear wheel. It is configured to brake the M and RR. It should be noted that only the shaft 1 is driven and the shaft 2 is a driven shaft.

However, in the one shown in FIG. 4 described above, the brake is applied to the two axles 1 and 2 of the rear wheels, so that the brake is applied to the axle 2 (driven wheel R) that is not driven during traction control. As a result, the driven wheel RR may be locked and the slip may be increased.

Therefore, as an example in which the driven wheels are not braked during traction control control, there is one shown in FIG. The same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

During traction control, the brake is applied only to the shaft 1 provided with the drive wheel (M), and pneumatic pressure is applied only to the air master cylinder 104 that controls the brake of the drive wheel (M). It was done like this. Pneumatic pressure is supplied to the driven wheels (RR) from an air master cylinder of another system that is common to the front wheels.

In the structure shown in FIG. 5, however, the above-mentioned problem does not occur during the traction control control, but during the anti-lock brake control, when the front wheel locks only, the front wheel and the driven wheel of the rearmost shaft 2 form one channel. Since the control is performed collectively by, the rearmost axle will be locked due to the axial load change of the rear axle due to the movement of the center of gravity during sudden braking on the road surface with a high friction coefficient such as asphalt, and there is a problem that the anti-lock braking performance is poor.

As a solution to the above-mentioned problems of the three-channel type, there is one shown in FIG. In this system, the left and right front wheels are on the same channel, and the four rear wheels can be controlled individually by independent channels.

As a result, only the wheels that are actually slipping can be controlled during antilock braking, and only the driving wheels that are slipping can be controlled during traction control. ..

[0015]

[Problems to be solved by the device]

 However, the one shown in FIG. 6 requires control of five channels, and therefore has a problem that the number of parts is extremely large and the cost is high as compared with the three-channel type.

The present invention has been made in view of the above matters, and it is possible to achieve both anti-lock braking and traction control with a small number of channels and to perform brake control only on the drive wheels that have caused an acceleration slip. A technical issue is to provide a traction control device for an axle vehicle.

[0017]

[Means for Solving the Problems]

 In order to solve the above technical problems, the present invention has a drive shaft 1 and a driven shaft 2 adjacent to the drive shaft 1, and each axle is provided with an air-over-hydraulic anti-lock brake. Independent air master cylinders 5 and 5 are connected to the left and right wheels of the drive shaft 1 and the driven shaft 2, and the wheel cylinders 25 and 35 of the drive shaft 1 and the driven shaft 2 are applied by hydraulic pressure from the air master cylinders 5 and 5, respectively. The structure of the traction control device for a multi-axle vehicle under pressure is as follows.

That is, the valves 6 a and 6 b are inserted in the middle of the hydraulic pressure path from the air master cylinders 5 and 5 to the wheel cylinder 35 side of the driven shaft 2. A balance piston 6c that slides due to the difference in hydraulic pressure between the left and right hydraulic pressure paths 81, 81 is provided, and the valve closes the hydraulic pressure path 81 on either the left or right hydraulic pressure side by the valve according to the movement of the balance piston. Configured to do.

As a result, the number of controls is 1 channel for the front wheels and 2 channels for the driving wheels, for a total of 3 channels, which can be implemented at low cost. Moreover, the structure is simple and maintainability is good.

[0020]

[Action]

 First, during normal braking, hydraulic pressure is applied from the air master cylinders 5R and 5L to the wheel cylinders provided on the left and right wheels of the drive shaft 1 and the driven shaft 2. At this time, since the average hydraulic pressure is applied to each wheel cylinder, the balance piston 6c in the balance valve 6 is in the neutral position, and the left and right hydraulic pressure passages 81R and 81L are in a circulating state.

Therefore, a uniform braking force can be applied to all wheels. Next, at the time of antilock braking, a command is given from the central control unit, and pulsating hydraulic pressure is given to each wheel cylinder from the air master cylinders 5R, 5L.

Next, at the time of traction control, a command is given from the central control unit, and hydraulic pressure is given from the air master cylinders 5R, 5L to the wheel cylinder of the wheel on which the left and right drive wheels have larger slip. For example, when only the right drive wheel slips, pressure fluid is applied to the wheel cylinders of the right drive wheel and the right driven wheel. At the same time, the balance piston 6c in the neutral position is moved by the pressure, and the high-pressure side hydraulic passage 81R is closed. Therefore, the pressing of the right driven wheel to the wheel cylinder is stopped and the drag of the brake on the driven wheel can be prevented.

Further, the number of controls is 1 channel for the front wheels and 2 channels for the driving wheels, for a total of 3 channels, which can be implemented at low cost. Furthermore, since the left and right hydraulic paths are connected by a balance valve, the structure is simple and maintainability is good.

Further, since there is no change in the electric circuit, the conventional ECU can be used as it is and can be implemented at a low cost.

[0025]

【Example】

 An embodiment of the present invention will be described with reference to FIGS. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. Machine elements with the same function located on the left and right of the vehicle are distinguished by adding L (left side) or R (right side) at the end of the number.

In this embodiment, in addition to the drive shaft 1, there are two driven shafts, that is, the drive wheels 61 provided on the drive shaft 1 located at the rear of the vehicle body and the driven wheels 2 provided on the rear of the driven shaft 2. It is applied to a three-wheeled vehicle with two rear wheels having a driving wheel 62 and a front wheel 63 provided on a driven (steering) shaft 3 provided at the front of the vehicle. The left and right front wheel brakes are commonly used for a pair of left and right rear wheels. This is a 3-channel system that controls 61 and 62 independently.

Each wheel is controlled by an air-over-hydraulic antilock brake. A brake valve 100 is connected to the brake pedal, and this brake valve 100 controls the air pressure from the air pressure input A to apply the control air pressure to the front wheel relay valve 101 and the rear wheel relay valve 151. It has become.

The air pressure from the relay valve 101 is applied to the air master cylinder 174 for the front wheel brake via the air control valve 102. The air master cylinder 174 is configured so that air pressure is converted into hydraulic pressure and the hydraulic pressure can be applied to the front wheel wheel cylinder 15.

On the other hand, the relay valve 151 is operated by the air from the brake valve 100, and the air of the pneumatic source A is supplied to the rear wheels via the relay valve 151, the two-way valves 103R and 103L, and the air control valves 112R and 112L. It is designed to be supplied to the air master cylinders 5R and 5L.

In the air master cylinder 5, air pressure is converted into hydraulic pressure, and brake fluid is applied to the wheel cylinders 25R, 25L, 35R, 35L provided on the drive shaft 1 and the driven shaft 2 adjacent to the drive shaft 1, respectively. It is designed to supply pressure. The hydraulic pressure paths 81R and 81L connecting the air master cylinders 5R and 5L and the wheel cylinders 25R and 25L are connected to the left and right of the wheel cylinders 25 and 35, respectively.

The two-way valves 103R and 103L have two inputs and one output. One input is connected to the relay valve 151 and the other input is connected to the traction control valve 3 as described above. The traction control valve 3 allows air to pass through only during traction control, and the air pressure from either one is sent to the air conditioner control valves 112R and 112L through the two-way valves 103R and 103L.

Valves 6a and 6b are inserted in the middle of the hydraulic pressure paths 81R and 81L from the air master cylinders 5R and 5L to the wheel cylinder 35 side of the driven shaft 2, respectively. The valves 6a and 6b have a structure as shown in FIG. That is, the valve 6a and the valve 6b urge the ball 6d in the liquid chamber 6s by the coil spring 6e, and the valve seat 6f is provided in the urging direction so that the ball 6d abuts the rod 6j. ..

Liquid pressure paths 81R and 81L are connected to the liquid chamber 6s. A cylinder 6g is provided in the balance valve 6, and a balance piston 6c is slidably provided in the cylinder 6g.

An o-ring is provided on the outer circumference of the balance piston 6g. Rods 6j are provided at both ends of the balance piston 6c, and the ball 6d is pushed by the tip of the rod 6j. A hydraulic pressure passage 81b is connected to the side wall of the cylinder 6g.

Both side walls of the balance piston 6g are pressed by the coil springs 6k, and the balance piston 6k is held at the neutral position.

The length of the rod 6j is set so that both valves 6a and 6b are separated from the valve seat 6f at the neutral position of the balance piston 6c. Then, for example, when the hydraulic pressure passage 81L on the left wheel side has a higher pressure than the hydraulic pressure passage 81R on the right wheel, pressure imbalance occurs, so the balance piston 6c moves.

On the contrary, when the hydraulic pressure passage 81L on the right wheel side becomes higher in pressure than the hydraulic pressure passage 81R on the left wheel, pressure imbalance occurs, so that the balance piston 6c moves in the direction shown in FIG. Moving.

An operation example will be described below. First, during normal braking, the air master cylinder 174 is actuated via the relay valve 101 and the air control valve 102 to brake the front wheels, and the air control valve 112 is actuated via the relay valve 151 and the two-way valve 103. The air master cylinder 5 pressurizes the wheel cylinders 25, 25, 35, 35 for the rear wheels. At this time, the brake fluid pressure is evenly applied to all wheel cylinders as usual to stop the vehicle body normally.

Next, when the brake is applied on a slippery road surface, the opening / closing control of the air conditioner control valves 102, 112R, 112L as well known by the command from the ECU 200 issued based on the rotation speed information from the rotation sensor S. Controls the brake pressure.

Next, a case of sudden acceleration on a split road surface (where the left and right wheels have different friction coefficients) will be described, for example, when the left friction coefficient is low and the right drive wheel excessively rotates. To do.

First, the traction control valve 3 operates in response to slip. In response to a command from the ECU 200, the air control valve 112R is closed and the air master cylinder 5R is operated.

Since there is no hydraulic pressure from the air master cylinder 5L, the balance piston 6c moves leftward as shown in FIG. 3 by the hydraulic pressure from the air master cylinder 5R, and the valve 6a is closed. As a result, the hydraulic pressure to be applied to the wheel cylinder 35 of the left driven wheel 62 is cut off, and the hydraulic pressure is applied only to the wheel cylinder 25 of the slipping drive bell 1.

This can prevent the driven wheels from being braked. As described above, dragging of the driven shaft 2 can be prevented. Moreover, since only a balance valve is required to be added, there is no change in the electric circuit and the conventional ECU can be used as it is and can be implemented at low cost.

When the left and right drive wheels slip at the same time, a well-known method of controlling engine output can be used instead of control by braking.

[0045]

[Effect of the device]

 According to the present invention, the balance valve is configured to operate so that the left and right braking forces are equalized, so that the trailing wheel drags when the traction control is activated without affecting the normal brake or the anti-lock brake. In addition, the electric system can be implemented at low cost because the conventional 3-channel type can be used as it is. In addition, the structure is simple and maintainability is good because only the balance valve is added.

[Brief description of drawings]

FIG. 1 is an overall system diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part for explaining the operation of one embodiment of the present invention.

FIG. 3 is a sectional view of an essential part for explaining the operation of one embodiment of the present invention.

[Fig. 4] System diagram of a conventional example

[Fig. 5] System diagram of conventional example

FIG. 6 is a system diagram of a conventional example.

[Explanation of symbols]

 1 ... Drive shaft, 2 ... Driven shaft, 3 ... Driven shaft, 5 ... Air master cylinder, 6 ... Balance valve, 25 ... Wheel cylinder, 35 ... Wheel cylinder, 81 ... Hydraulic path, 6a, 6b ...

Claims (1)

[Scope of utility model registration request] 1. A drive shaft and a driven shaft adjacent to the drive shaft, each wheel being provided with an air-over-hydraulic antilock brake, and independent air for the left and right wheels of the drive shaft and the driven shaft. Master cylinders are connected respectively,
In a traction control device for a multi-axle vehicle that pressurizes the wheel cylinders of the drive shaft and the driven shaft with the hydraulic pressure from these air master cylinders, valves are installed in the middle of the hydraulic pressure path from the air master cylinder to the wheel cylinder side of the driven shaft. A balance piston that is inserted and slides due to the difference in hydraulic pressure between the left and right hydraulic pressure paths is provided, and the valve closes the hydraulic pressure path on either the left or right side with the increased hydraulic pressure according to the movement of the balance piston. A traction control device for a multi-axis vehicle, which is configured as described above.