JPH068135U - Valves in air-break systems - Google Patents

Abstract

(57) [Summary] [Purpose] To make valves lighter and easier to manufacture in automobile air-brake systems. [Structure] An operating piston of a valve is made of synthetic resin, and an elastic body for a seal is provided between the piston and an aluminum alloy cylinder to which the piston is fitted and which makes one round in the circumferential direction of the piston outer diameter. Further, the piston outer diameter is located at a position axially separated from the seal elastic body, and the radial gap between the piston outer diameter and the cylinder is kept constant in the circumferential direction. An elastic body is installed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a valve in an air brake system for a vehicle.

[0002]

[Prior art]

 FIG. 2 is a side sectional view showing a conventional relay valve in an air brake system. In FIG. 2, a piston 5 is fitted into a cylinder 1a formed in a body-1 so as to be slidable in an axial direction, and a side plate 2 is screwed to the body-1 so as to seal the cylinder 1a. The side wall 2, the piston 5, and the displacement chamber 1d formed by the cylinder 1a are communicated with a pipe line from the brake valve through the connection hole 2a, and the piston 5 has a sheath at the tip protruding rightward in the axial direction. The upper surface 5c is formed, and the urging force of the spring 5d is applied to the piston 5 toward the displacement chamber 1d.

A chamber 1e enclosing a spring 5d is connected to a brake device of a wheel through a connection hole 1c, a valve seat 1h is provided on a body-1, and a valve seated selectively on the valve seat 1h. 4 is fitted in the wall member 1i so as to be slidable in the axial direction, and the valve 4 is provided with a biasing force of a spring 4b toward the valve seat 1h side so that a port formed in the valve 4 is provided. 4c selectively connects the chamber 1e and the chamber 1f, and a check valve 1g is provided between the chamber 1f and the atmosphere.

The operation of FIG. 2 is as follows. When the brake pedal (not shown) is not depressed, the brake valve (not shown) interlocked with the brake pedal is not operated, so that the pushing chamber 1d is at atmospheric pressure. The piston 5 is biased to the left end as shown by the biasing force of the spring 5d. As a result, the seat surface 5c of the piston 5 is at a position that is floated to the left of the drawing from the valve surface 4a of the valve 4, the port 4c is in the valve open state, and the connection hole 1c is in the chamber 1e, It is open to the atmosphere through the port 4c, the chamber 1f and the check valve 1g.

When the driver depresses the brake pedal in the above state, compressed air proportional to the depression is supplied from the brake valve to the displacement chamber 1d through the connection hole 2a. Due to this supply, the piston 5 is pressed to the right in FIG. 2 against the biasing force of the spring 5d, whereby the seat surface 5c is seated on the valve surface 4a of the valve 4, and the piston 5 When the sheet is pressed, the sheet surface 5c moves to the right to lift the valve 4 from the valve seat 1h to the right.

As a result, the port 4c is closed by the sheet surface 5c and the connection hole 1b communicates with the chamber 1e, so that the compressed air from the air tank is connected to the connection hole 1b, the chamber 1e and the chamber 1e. It is supplied to the brake device of the wheel through the connection hole 1c, and as a result, the brake is applied to the wheel. When compressed air enters the chamber 1e from the air tank as described above in the process of applying the brake, the pressure in the chamber 1e rises correspondingly, and the piston 5 is pushed back. .

After all, the pushing back is performed by pushing the piston 5 to the right by the air pressure generated in the pushing chamber 1d, pushing the piston 5 back by the air pressure entering the chamber 1e from the air tank, and adding the spring 5d. Equilibrium is equal to the sum of powers. That is, in the equilibrium state, the seat surface 5c is seated on the valve surface 4a and the valve surface 4a is seated on the valve seat 1h, an air pressure proportional to the air pressure in the displacement chamber 1d is generated, and the displacement chamber 1c is generated. A brake proportional to the air pressure sent to 1d is applied to the wheels.

Further, when the brake valve is released from being depressed, the air pressure in the displacement chamber 1d also decreases, and the seat surface 5c floats above the valve surface 4a as shown in FIG. The air in the chamber 1e communicating with the air is released to the atmosphere through the port 4c, the chamber 1f and the check valve 1g, and the break is released.

[0009]

[Problems to be solved by the device]

 In order to reduce the weight of the relay valve that operates as described above, both the body-1 and the piston 5 are made of aluminum alloy. However, in recent years, in order to reduce the fuel usage rate of automobiles, it is required to reduce the weight of each component used in the automobile. An object of the present invention is to provide a relay valve in an air-brake system that meets such a demand for weight reduction.

[0010]

[Means for Solving the Problems]

 The present invention is an improvement of the conventional relay valve as described below. The structure of the conventional relay valve is as follows. A valve that is selectively seated on a valve seat provided between the conduit from the air tank and the conduit to the brake device of the wheel is given a spring biasing force in the direction of the valve seat. ing. That is, when the valve is seated on its seat, it closes the line from the air tank to the line to the wheel brake device, and the valve is floating above the seat. , There is a communication between the conduit from the air tank and the conduit to the wheel brake device.

In addition, in the valve, a port that selectively communicates between the pipeline to the wheel brake device and the atmosphere is opened toward the valve seat side and fixed to the valve seat. The piston, which is fitted to the bored cylinder so as to be slidable in the axial direction, is selectively fitted with the port at the tip protruding toward the valve side in the axial direction. It forms the closing sheet. That is, when the seat surface closes the port, it closes the communication between the conduit to the wheel braking device and the atmosphere, and the seat surface opens the port. During this time, the conduit to the wheel brake device is open to the atmosphere.

A pipe from the brake valve communicates with the displacement chamber formed by the piston and its cylinder, and another spring biasing force is applied to the piston in the direction away from the valve. ing. That is, the seat surface of the piston operated by the air pressure from the brake valve operates the valve to supply the pressure air from the air tank to the conduit to the wheel brake device. Alternatively, it is configured such that the pipeline to the wheel brake device is opened to the atmosphere.

Such a conventional relay valve is improved as follows. The piston is made of a synthetic resin material, and a groove is formed around the outer diameter of the piston in a circumferential direction, and the groove is made of an elastic material for sealing between the outer diameter of the piston and the cylinder. A body is provided, and further, the piston outer diameter is located at a position axially separated from the seal elastic body, and a radial clearance between the piston outer diameter and the cylinder is provided in the circumferential direction. An elastic body that holds it constant is provided.

[0014]

【Example】

 FIG. 1 is a side sectional view showing a relay valve in an air-brake system according to the present invention. In FIG. 1, a piston 3 is fitted in a cylinder 1a formed in a body-1 so as to be slidable in an axial direction, and a side plate 2 is screwed to the body-1 so as to seal the cylinder 1a. The side wall 2, the piston 3, and the displacement chamber 1d formed by the cylinder 1a are communicated with a conduit from the brake valve, and a seat surface 3f is formed at the tip of the piston 3 protruding rightward in the axial direction. The urging force of the spring 3g is applied to the piston 3 toward the displacement chamber 1d.

The chamber 1e enclosing the spring 3g is connected to the brake device of the wheel via the connection hole 1c, and the body-1 is provided with the valve seat 1h, and the valve seat 1h is selectively seated on the valve seat 1h. Numeral 4 is fitted to the wall member 1i so as to be slidable in the axial direction, and the valve 4 is provided with a biasing force of a spring 4b toward the valve seat 1h so that the valve 4 bored in the valve 4 is pierced. The port 4c selectively connects the chamber 1e and the chamber 1f, and a check valve 1g is provided between the chamber 1f and the atmosphere.

The operation of the above embodiment of the present invention is as follows. When the brake pedal (not shown) is not depressed by the driver, the brake valve (not shown) linked to the brake pedal is not operated. Therefore, when the brake valve is not operated, the displacement chamber 1d becomes atmospheric pressure, and the piston 3 is biased to the left end as shown by the biasing force of the spring 3g. As a result, in this state, the seat surface 3f of the piston 3 is separated leftward from the valve surface 4a of the valve 4, the port 4c is in the open state, and the connection hole 1c is in the chamber 1e and the port 1c. -To the atmosphere through the chamber 4f, the chamber 1f, and the check valve 1g. That is, the pipeline to the brake device in the wheel is open to the atmosphere, and the brake device is in a non-braked state.

When the driver depresses the brake pedal in the above state, air from the brake valve (not shown) having an air pressure proportional to the amount of depression is pushed through the connection hole 2a into the displacement chamber. It will be supplied to 1d. The supplied air pressure pushes the piston 3 rightward in FIG. 2 against the biasing force of the spring 3g, whereby the seat surface 3f of the piston 3 is seated on the valve surface 4a of the valve 4, Further, the pressing of the piston 3 shifts the seat surface 3f to the right and moves the valve 4 away from the valve seat 1h to the right.

As a result, the port 4c is closed by the sheet surface 3f, and the connection hole 1b communicates with the chamber 1e, so that compressed air from the air tank (not shown) is connected to the connection hole. 1b, the chamber 1e and the connection hole 1c are supplied to the brake device of the wheel, and the brake is applied to the wheel. When compressed air enters the chamber 1e from the air tank as described above during the process of applying a brake, the pressure in the chamber 1e rises accordingly, and the piston 3 is moved to the left. Push it back.

After all, the pushing back is performed by the force Fr that pushes the piston 3 to the right by the air pressure generated in the pushing chamber 1d, and the force Fl that pushes the piston 3 to the left by the air pressure that has entered the chamber 1e and the spring 3g. The equilibrium occurs when the sum of the biasing forces Fs of Fs is equal (Fr = Fl + Fs). That is, in the equilibrium state, the seat surface 3f is seated on the valve surface 4a and the valve surface 4a is seated on the valve seat 1h, and an air pressure proportional to the depression amount of the brake valve is applied from the connection hole 1c to the wheel. The brake is applied to the brake device, and the brake is applied to the wheels in proportion to the amount of depression.

Further, when the brake valve is released from being depressed, the air pressure in the displacement chamber 1d is also reduced and the seat surface 3f is separated from the valve surface 4a as shown in FIG. The air in the chamber 1e communicating with the chamber 1e is released to the atmosphere through the port 4c, the chamber 1f and the check valve 1g, and the brake is released.

The relay valve in FIG. 1 of the present invention operates as described above, but the body-1 is made of an aluminum alloy as in the conventional case, and the piston 3 is lightweight and mass-produced. It is made of injection-molded synthetic resin material (for example, polyacetal resin) so as to be suitable. However, when the cylinder 1a is made of aluminum alloy and the piston 3 is made of synthetic resin as described above, the fitting gap of the piston 3 to the cylinder 1a is the same as that of the conventional piston made of aluminum alloy. You can't do the same as you do. This is because the linear expansion coefficient of the synthetic resin is different from that of the aluminum alloy, and the fitting gap changes greatly due to changes in the ambient temperature. For this reason, the fitting gap between the piston 3 and the cylinder 1a in the above-described embodiment is sufficiently larger than that in the case where the piston and the cylinder are made of aluminum alloy, and is required within the change of the ambient temperature. Secures a fitting gap.

In this case, if the radial gap between the piston 3 and the cylinder 1a is increased in this way, the piston 3 is likely to tilt from the axial center in its axial movement. When the piston 3 is tilted from the axis, the seat surface 3f also tilts with respect to the valve surface 4a, causing the following problems. That is, when the seat surface 3f is seated on the valve surface 4a and the valve 4 is floated rightward from the valve seat 1h, the seat surface 3f is in close contact with the valve surface 4a over its entire circumference. It is necessary to sit down and completely close the communication between the chamber 1e and the chamber 1f.

However, when the seat surface 3f is seated on the valve surface 4a while being inclined with respect to the axis as described above, the seat surface 3f causes the valve 4 to float above the valve seat 1h and the air tank side. Even if the compressed air is introduced into the chamber 1e, the compressed air introduced into the chamber 1e causes the port 4c to pass through the gap created by the inclination of the valve surface 4a and the seat surface 3f on which it is seated. It will leak out through the air.

The present invention takes the following measures against the tendency that the piston 3 is easily tilted from the shaft center by adopting the piston 3 made of the synthetic resin material as described above. A groove 3a is cut around the outer circumference of the piston 3 in the circumferential direction, and an elastic body 3b for sealing is provided between the piston 3 and the cylinder 1a in the groove 3a. The elastic body 3b elastically holds a radial gap between the piston 3 and the cylinder 1a in the circumferential direction of the piston 3 at one position in the axial direction.

Further, at another position on the outer diameter of the piston 3 that is axially distant from one position in the axial direction of the piston 3, a groove 3c that makes one round in the circumferential direction is cut and the groove 3c is formed. In the above, an elastic body 3d is provided so as to maintain a constant radial gap between the outer diameter of the piston 3 and the cylinder 1a. In this way, the elastic body 3b and the elastic body 3d do not incline the piston 3 on the cylinder 1a from the axial center at the two positions of the piston 3 on the outer diameter, that is, one position in the axial direction and the other position in the axial direction. To support. In addition, the perforation 3e formed in the piston 3 communicates with the chamber 1e a gap formed by the piston 3 and the cylinder 1a between the elastic body 3b and the elastic body 3d.

In the above embodiment, the elastic body 3d is provided so as to make one round in the outer diameter circumferential direction of the piston 3. However, the elastic body 3d may be interposed so as to keep the radial gap between the outer diameter of the piston 3 and the cylinder 1a constant. Therefore, the elastic body 3d may be arranged separately at equally divided positions in the outer circumferential direction of the piston 3. The piston structure of the relay valve can be applied to the piston of the brake valve and is not limited to the relay valve.

[0027]

[Effect of device]

 As is clear from the above description, the effects of the present invention are as follows. The piston 3 is held on the cylinder 1a by the elastic bodies 3b and 3d at two positions, namely, one position in the axial direction on the outer diameter of the piston 3 and the other position in the axial direction. Even if a piston 3 made of a different material is used, the piston 3 can be made of synthetic resin without impairing the performance of the relay valve. As a result, it became possible to reduce the weight of the relay valve as an automobile part, and to make the piston 3 a synthetic resin, enabling injection molding of the piston 3 and mass production of the piston 3. Became easier. This also makes it easier to reduce the manufacturing unit price of the relay valve.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a relay valve in an air-brake system according to the present invention.

FIG. 2 is a side sectional view showing a relay valve in a conventional air-brake system.

[Explanation of symbols]

1 body, 1a cylinder, 1d pushing chamber,
1h valve seat, 3 pistons, 3a groove, 3b and 3d elastic body, 3f sheet surface, 3g spring, 4 valve, 4a valve surface, 4b spring,
4c port.

Claims (1)

[Scope of utility model registration request] 1. A valve selectively seated on a valve seat provided between a conduit from an air tank and a conduit to a wheel braking device has a spring in the direction of the valve seat. A port, which gives an urging force and selectively communicates between the line to the wheel brake device and the atmosphere, is opened toward the valve seat side and is fixed to the valve seat. The piston, which is fitted into the bored cylinder so as to be slidable in the axial direction, has a seat surface that selectively closes the port at the tip protruding toward the valve side in the axial direction. The pipe from the brake valve communicates with the displacement chamber formed by the piston and the cylinder, and another spring biasing force is applied to the piston in the direction away from the valve. In this configuration, the piston is made of a synthetic resin material, and the piston The grooves which Kezu設 by round in the circumferential direction of the outer diameter of the down,
An elastic body for a seal is provided between the piston outer diameter and the cylinder, and the piston outer diameter is located at a position axially separated from the seal elastic body. A valve in an air-brake system, characterized in that an elastic body for holding a constant radial clearance between the piston outer diameter and the cylinder in the circumferential direction is provided.