JPH09193787A - Relay valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the output pressure in a wide range without replacement of a return valve. SOLUTION: A relay valve is so constructed that a reaction force pressure chamber 28 is formed in a valve housing 2. A reaction piston 27 for energizing a relay piston 18 in the return direction with the pressure in the reaction force pressure chamber 28 is provided to receive one input information among the car speed, load and road status showing the running condition of a vehicle and the rotating speed of a wheel and introduce the control pressure regulated according to an output signal output by a controller into the reaction force pressure chamber 28, thereby controlling the output pressure in an output port at time of outgoing of the relay piston 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a relay valve used for improving the performance of a brake of a vehicle brake device.

[0002]

2. Description of the Related Art FIG. 6 is a schematic configuration diagram showing a conventional vehicle brake device. This brake device has an indicator pressure port 3, a supply port 4 and an output port 5 in a valve housing 2 of a relay valve 1, and a brake valve 8 and an air reservoir 9a are connected to the instruction pressure port 3 via a pipe line 7a. An air reservoir 9b is connected to the supply port 4 via a conduit 7b, and an output port 5
The brake booster 10 is connected to the pipe via a pipe 7c. The brake booster 10 is provided with a pressure transmitter 11, and a wheel cylinder 13 for operating a brake shoe (not shown) is connected to the pressure transmitter 11.

In the relay valve 1, as shown in FIG. 7, a relay piston 18 having an exhaust cutoff valve body 17 is arranged in a valve housing 2, and a supply / discharge valve body 20 is provided below the relay piston 18. The relay piston 18 is biased in the returning direction by the return spring 22, and the supply / discharge valve body 20 is compressed by the compression spring 2.
It is biased by 3 and is in contact with the valve seat 24 provided in the valve housing 2.

Further, in the relay valve 1 in the non-operating state shown in FIG. 7, the exhaust cutoff valve body 17 of the relay piston 18 is separated from the supply / discharge valve body 20 so that the output port 5 and the exhaust passage 19 are communicated with each other. The supply / discharge valve body 20 is in contact with the valve seat 24 by the urging force of the compression spring 23 to shut off the connection between the supply port 4 and the output port 5.

In such a brake device, the relay piston 18 is moved forward against the biasing force of the return spring 22 by the instruction pressure supplied from the air reservoir 9a to the instruction pressure port 3 by the operation of the brake valve 8, and the relay piston 18 is moved forward. The output pressure is sent out from the output port 5 to the brake booster 10 by the forward movement of. Brake booster 1 that received this output pressure
At 0, the working piston (not shown) of the pressure transmitter 11 slides and the brake fluid is pushed out from the outlet 11a,
This brake fluid operates the wheel cylinders 13 to press the brake shoes against the brake drum or the like, whereby the brake operation is performed.

In this relay valve 1, when the input / output pressure characteristic showing the relationship between the instruction pressure IP and the output pressure OP in FIG. 8 is a straight line as shown by the broken line, when changing this, By replacing the return spring 22,
The input / output pressure characteristics shown by the solid line were obtained.

[0007]

However, in the above-mentioned conventional relay valve 1, when the return spring 22 is replaced when the input / output pressure characteristic is changed, the linear broken line in FIG. 8 moves in parallel to the position indicated by the solid line. Therefore, there is a drawback that the degree of freedom and the range of changing the characteristics are extremely limited.

The present invention has been made in view of the above conventional drawbacks, and an object thereof is to provide a relay valve capable of controlling an output pressure in a wide range without replacing a return spring.

[0009]

In order to achieve the above object, the present invention comprises a valve housing having an indicator pressure port, a supply port and an output port, and an exhaust cutoff valve body disposed in the valve housing. The relay piston communicates with the output port and the exhaust passage in a non-operating state, and at the same time disconnects the supply port and the output port, and in the operating state in which the relay piston moves forward, the output port and the exhaust passage A supply / discharge valve body that connects the supply port and the output port to each other at the same time when the relay piston is moved forward by the command pressure supplied to the command pressure port by operating a brake valve. In the relay valve that sends output pressure through
A reaction force pressure chamber is formed in the valve housing, and a reaction force piston that urges the relay piston in the returning direction by the pressure of the reaction force pressure chamber is provided to receive input information indicating a running state of the vehicle. The control pressure adjusted based on the output signal output from the controller is introduced into the reaction force pressure chamber to control the output pressure at the output port when the relay piston moves forward.

[0010]

1 is a longitudinal sectional view showing a relay valve according to a first embodiment of the present invention, and FIG. 2 shows a vehicle brake device equipped with the relay valve according to the embodiment of the present invention. It is a schematic configuration diagram, the same parts as those of the conventional art are denoted by the same reference numerals, and duplicate description of those parts will be omitted.

In FIG. 1, a relay valve 1A comprises a valve housing 2, an indicator pressure port 3, a supply port 4 and an output port 5, and a control pressure port 6 in addition to these, and a reaction force pressure chamber communicating with the control pressure port 6. 28 is formed in the valve housing 2, a reaction force piston 27 for urging the relay piston 18 in the return direction by the pressure of the reaction force pressure chamber 28 is provided, and the return spring 22 shown in FIG. 7 is omitted.

Referring to FIG. 2, in the vehicle brake device according to this embodiment, the outlet 30a of the pressure control valve 30 is connected to the control pressure port 6 via a pipe, and the inlet 30b of the pressure control valve 30 is connected. Air reservoir 9c and pressure control valve 3
0 is provided with a controller 32 for sending a control signal, and the controller 32 receives the input information of at least one of vehicle speed, load, road surface condition, wheel rotation speed, etc., which represents the running state of the vehicle. The control pressure adjusted by the pressure control valve 30 based on the output signal to be output is used as the reaction force pressure chamber 2
8 to control the output pressure at the output port 5 when the relay piston 18 moves forward.

In the valve housing 2, an upper housing block 15 and a lower housing block 16 are combined to form a cylinder chamber 36. The upper housing block 15 is provided with an indicator pressure port 3 and the lower housing block is provided. In addition to the supply port 4 and the output port 5, the control port 16 has a control pressure port 6 on the opposite side of the output port 5. The lower housing block 16 integrally includes a large-diameter cylinder 40 and a small-diameter cylinder 41 that are concentric and project upward at substantially the same height, and the upper end is open between the large-diameter cylinder 40 and the small-diameter cylinder 41. The groove 42 is formed, and the lower portion of the tubular reaction force piston 27 is slidably fitted into the annular groove 42, and the reaction force pressure chamber 28 is provided between the bottom surface of the annular groove 42 and the lower end surface of the reaction force piston 27. Are formed.

Further, the lower housing block 16 is
Control pressure introducing hole 4 for communicating the reaction pressure chamber 28 with the control pressure port 6
3, an output pressure communication hole 44 for communicating the cylinder chamber 36 with the output port 5, a guide hole 45 in the substantially center and a through hole 46 following the guide hole 45, and a valve chamber 47 similar to the conventional one is formed in the lower part. There is.

The relay piston 18 integrally has a piston body 50 slidable in the cylinder chamber 36 and a guide receiving rod 51 projecting downward, and the exhaust cutoff valve body 17 is provided at the lower end of the guide receiving rod 51. The guide receiving rod 51 is slidably fitted into the inner periphery of the guide hole 45, and when compressed air is sent from the air reservoir 9a to the instruction pressure port 3 by the operation of the brake valve 8, it moves downward. Exhaust cutoff valve body 1
7 abuts the supply / discharge valve body 20 through the through hole 46, blocks the exhaust passage 19, and simultaneously connects the supply port 4 and the output port 5. Further, the relay piston 18 is the piston body 5
0 and an outer periphery of the guide receiving rod 51 have annular seal grooves 50a and 51a, respectively, and seal members 53 and 54 are arranged in the respective seal grooves.

The supply / discharge valve body 20 has a flange-shaped upper end portion 56.
And a cylindrical body 57 are integrally formed, and the spring receiving member 58 is fitted to the inner circumference of the exhaust passage 19 of the lower housing block 16.
Of the cylindrical body 57 is slidably fitted and guided in the guide hole 58a, and is biased upward by the compression spring 23.
In the non-actuated state shown in FIG. 1, the upper end portion 56 abuts the valve seat 24 to communicate the output port 5 with the exhaust passage 19, and at the same time blocks the supply port 4 and the output port 5.

The reaction force piston 27 has a cylindrical shape whose outer diameter is smaller than that of the piston body 50 and whose inner diameter is larger than that of the guide receiving rod 51. The reaction force piston 27 is arranged below the piston body 50 and has a lower portion fitted into the annular groove 42. To define the reaction force pressure chamber 28, and the lower surface of the piston body 50 is in contact with the upper end surface,
Annular seal grooves 27a and 27b are provided on the inner and outer circumferences of the portion fitted in the annular groove 42, and seal members 60 and 61 are arranged in the seal grooves. The reaction piston 27 is
It has a ventilation groove 27c.

The reaction force pressure chamber 28 is formed between the bottom surface of the annular groove 42 and the lower end surface of the reaction force piston 27, and has an annular shape with a substantially uniform cross section. The compressed air in the air reservoir 9c is pressure controlled. The control pressure adjusted by the valve 30 is supplied through the control pressure port 6 and the control pressure introduction hole 43.

The reaction force piston 27 receives an urging force in the returning direction by the control pressure introduced from the air reservoir 9c to the control pressure port 6 and the reaction force pressure chamber 28 through the pressure control valve 30 and relays the urging force. It is transmitted to the piston 18.

The controller 32 receives input information of at least one of vehicle speed, load, road surface condition, wheel rotation speed, etc., which represents the running state of the vehicle to be braked, and outputs an output signal to the pressure control valve 30. The pressure control valve 3 outputs the compressed air in the air reservoir 9c based on the output signal.
0 is adjusted to control pressure, and this control pressure is applied to the reaction force pressure chamber 2
It is intended to be introduced in 8.

The operation of the brake system according to the first embodiment will be described. When the brake pedal is depressed, the compressed air in the air reservoir 9a is sent to the instruction pressure port 3 according to the depression amount, the relay piston 18 moves forward against the urging force of the reaction force piston 27, and the exhaust cutoff valve body 17
Is in contact with the upper end portion 56 of the supply / discharge valve body 20 to block the exhaust passage 19, and when the relay piston 18 moves further downward, the supply / discharge valve body 20 is pushed down and separated from the valve seat 24, and is connected to the supply port 4. The brake booster 1 communicates with the output port 5, and the output pressure for brake operation is output through the output port 5 through the pipe line 7c.
Sent to 0. In the brake booster 10 that has received this output pressure, an internal working piston (not shown) of the pressure transmitter 11 slides to push out brake fluid from the outlet 11a, and this brake fluid operates the wheel cylinder 13 to operate the brake shoe. The brake is operated by pressing it against the brake drum or the like.

FIG. 3 is a graph showing an example of the input / output pressure characteristics of the relay valve according to the first embodiment, with the horizontal axis representing the instruction pressure IP and the vertical axis representing the output pressure OP. In this relay valve 1A, the input / output pressure characteristic when the control pressure is small is the straight line A, but the input / output pressure characteristic when the control pressure is large is the straight line B, and P ₂ for each same arbitrary command pressure IP. , P ₁ are obtained, and an arbitrary output pressure between these large and small output pressures P ₂ and P ₁ can be obtained simply by changing the control pressure. Further, the return spring 22 can be omitted.

FIG. 4 is a vertical sectional view showing a relay valve according to a second embodiment of the present invention, and the same parts as those in the first embodiment are designated by the same reference numerals. In this relay valve 1B, the projecting height of the small diameter cylinder 41 is made smaller than that of the large diameter cylinder 40, and the width of the annular groove 42 is made large. The reaction force piston 27 is integrally provided with the inward flange 63, and the reaction force is increased. Annular seal grooves 27a and 63a are formed on the outer circumference of the piston 27 and the inner circumference of the inward flange 63, and the seal members 60 and 61 are fitted in the seal grooves. The piston 18 is biased.

FIG. 5 is a vertical sectional view showing a relay valve according to a third embodiment of the present invention, and the same parts as those in the first embodiment are designated by the same reference numerals. In this relay valve 1C, the valve housing 2 is constructed by assembling the cover 14 to the upper housing block 15, and the upper housing block 15 is provided with the lateral indicating pressure port 3 and the control pressure port 6, and the indicating pressure port. 3 is communicated with the indicator pressure chamber 67 via a communication passage 66.

In the relay valve 1C, the reaction force piston 27 is arranged in the reaction force cylinder chamber 68 formed in the upper housing block 15, and the reaction force pressure chamber 28 is provided above the relay piston 18. The reaction bolt 27 is attached to the relay piston 18 by screwing the connecting bolt 70, which is passed through the through hole 69 at the bottom of the upper housing block 15, into the relay piston 18, and the reaction piston 27 is attached to the relay piston 18 by using the return spring 65 having a small spring constant. It gives a biasing force.

The reaction force piston 27 has a seal holding member 71 fitted on the inner peripheral side thereof and prevented from coming off by a snap ring 72, and a seal member 73 provided on the outer peripheral side of the piston itself,
Seal member 7 provided along the outer periphery of the seal holding member 71
The outer circumference and the inner circumference are sealed by 4 and a reaction force pressure chamber 28 is defined in the lower part of the reaction force cylinder chamber 68.

The reaction force pressure chamber 28 communicates with the control pressure port 6 through a control pressure introduction hole 43 provided in the upper housing block 15. The atmospheric pressure chamber 75 on the upper side of the reaction piston 27 is opened to the atmosphere through the communication passage 76, and the filter 77 is arranged in the middle of the communication passage 76. Further, a seal member 78 is arranged on the inner periphery of the through hole 69 at the bottom of the upper housing block 15, and this portion is sealed.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

[0029]

According to the present invention, the adjustment is performed based on the output signal output from the controller upon receiving at least one input information of the vehicle speed, the load, the road surface condition, the wheel rotation speed, etc., which represents the running state of the vehicle. The control pressure is introduced into the reaction force pressure chamber formed in the valve housing, and the pressure of the reaction force pressure chamber urges the relay piston in the return direction to output the output pressure at the output port of the relay piston in the forward movement. By controlling, there is an effect that an appropriate output pressure can be controlled in a wide range without replacing the return spring.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing a relay valve according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a vehicle brake device using a relay valve according to an embodiment of the present invention.

FIG. 3 is a graph showing input / output pressure characteristics of the relay valve according to the first embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a relay valve according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view showing a relay valve according to a third embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a vehicle brake device using a conventional relay valve.

FIG. 7 is a vertical sectional view showing a conventional relay valve.

FIG. 8 is a graph showing input / output pressure characteristics of a conventional relay valve.

[Explanation of symbols]

 1A Relay valve 2 Valve housing 3 Indication pressure port 4 Supply port 5 Output port 6 Control pressure port 17 Exhaust cutoff valve body 18 Relay piston 19 Exhaust passage 20 Supply / discharge valve body 24 Valve seat 27 Reaction force piston 28 Reaction force chamber 32 Controller

Claims (1)

[Claims] 1. A valve housing having an indicator pressure port, a supply port and an output port, a relay piston having an exhaust cutoff valve body disposed in the valve housing, and the output port and the exhaust passage in a non-operating state. The supply port and the output port are cut off at the same time when they are communicated, and the output port and the exhaust passage are cut off in the operation state in which the relay piston moves forward, and at the same time, the supply port and the output port are connected. In a relay valve comprising a supply and discharge valve body, which forwards the relay piston by an instruction pressure supplied to the instruction pressure port by operating a brake valve to send an output pressure through the output port,
A reaction force pressure chamber is formed in the valve housing, and a reaction force piston that urges the relay piston in the returning direction by the pressure of the reaction force pressure chamber is provided to receive input information indicating a running state of the vehicle. A relay valve, wherein a control pressure adjusted based on an output signal output from a controller is introduced into the reaction force pressure chamber to control the output pressure at the output port when the relay piston moves forward.