JPS629471B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in pressure control valves used in brake systems and the like in vehicles.

Conventionally, pressure control valves used in vehicle spring brakes, etc. are of the reaction type, in which the operating pressure acts on the input material for pressure setting and causes a reaction to the input material, and the Since the pressure is balanced, there is a non-reaction type that does not apply the reaction to the input material.

The former model above has a horizontal format when attached to the vehicle floor, and most of it can be mounted under the driver's seat, leaving the control lever part on the main body, making effective use of the space inside the vehicle. Although it is possible, since the aforementioned reaction force exists on the cam surface interposed between the input material and the valve part,
The cam has a disadvantage of poor durability.

On the other hand, while the latter type does not have this reaction force, it has a large external size and is installed vertically, making it impossible to mount it effectively under the driver's seat. It is.

An object of the present invention is to provide a pressure control valve that eliminates the disadvantages of both of the above and combines the advantages of both.

To explain the present invention based on an embodiment, FIG. 1 shows a side sectional view of a pressure control valve as an embodiment of the present invention, and FIG. 2 shows a cam body 5 in FIG. 1. This shows the positive view.

A side plate 1a is fastened to the housing 1 with a plurality of bolts, and a piston body 2 is fitted into a cylinder 1b cut into the housing 1 so that the cylinder 1b can slide in the axial direction. A chamber 2d formed by the side plate 1a and the piston body 2 is opened to the atmosphere through the connection hole 1c, and the spring 2a
provides a biasing force that biases the piston body 2 upward.

A pressure chamber 2c formed in the axial middle of the piston body 2 communicates with a constant pressure source (not shown) via a connecting hole 1d, and is a cylinder whose upper end surface in the axial direction of the piston body 2 is exposed. A pressure chamber 2e is formed within 1f, and the pressure chamber 2e communicates with a vehicle brake system (not shown) via a connection hole 1e.

A port 2f is formed in the piston body 2 between the pressure chamber 2c and the pressure chamber 2e, and the valve 3 is axially inserted into the cylinder 2b of the piston body 2 cut between the chamber 2d and the pressure chamber 2c. The valve 3 is provided with a perforation 3a that communicates with the chamber 2d, and the spring 3b is inserted in the direction in which the valve seat 3c formed at the shaft end of the valve 3 seats on the port 2f. It gives an auxiliary force to.

A pusher 4 is fitted into a cylinder 1f cut into the housing 1 so as to be able to slide in the axial direction, and a cam body 5 having a cam surface 5a is fitted into the pusher 4. The pin 1i fitted to the side wall 1g of the housing 1 prevents the cam body 5 from rotating around the cylinder 1f axis, and the tip of the input member 6 is
The cylinder 1f is fitted into the pusher 4 in a state that allows rotation around the axis, and an open hole 4b is bored in the sealing surface 4c cut at the shaft end of the pusher 4, and the input material 6 The end surface 6a is exposed to the open hole 4b, and a sealing material 6b such as an O-ring is attached to the fitting surface between the pusher 4 and the input material 6, and the pin fitted in the radial direction of the input material 6 6d is a cam follower that rotatably contacts the cam surface 5a, and the spring 4a is connected to the cam surface 5a via the piston body 2.
Pusher 4 is urged upward.

The input material 6 can rotate around the axis together with the coupling 7 by the serrations 7b,
In addition, a washer 6e is attached to the input material 6 by a bolt 6f.
As a result, the input member 6 holds the side wall 1g and the coupling ring 7 between the shoulder 6c and the washer 6e, and the coupling ring 7 is fitted into the housing 1 so as to be rotatable around the axis. A sealing material 7c such as an O-ring is attached to the fitting surface, and a lever 7a is screwed onto the coupling ring 7.

In the configuration shown in FIGS. 1 and 2 above,
To explain its action, when the lever 7a is operated and the coupling ring 7 is rotated around the axis of the input member 6, the pin 6d fixed to the input member 6 is moved from the input shaft 6.
rotate around the axis of

As a result, when the pin 6d is rotated in the direction of moving to the left in FIG.
and press down the pusher 4, and conversely, in FIG. 2, the input material 6
When the lever 7a rotates, the pusher 4 and the cam body 5 are pushed up by the urging force of the spring 4a, and the axial position of the pusher 4 becomes proportional to the operating angle θ of the lever 7a.

In this embodiment, the cam surface 5a is provided on the side of the pusher 4, and the side of the input material 6 is used as a cam follower. As long as the movement is converted into a movement of good.

When the lever 7a is further operated from the above state and its operating angle reaches θo, the sealing surface 4c reaches a position where it contacts the valve seat 3c, and the pressure chamber 2e
The communication with the chamber 2d is closed, and as the pusher 4 is pushed down further, the pusher 4 pushes down the valve 3, opening the valve seat 3c from the port 2f, and compressing from a constant pressure source. Air flows through the connection hole 1d, pressure chamber 2c and port 2f to the pressure chamber 2e.
The operating pressure of the pressure chamber 2e increases. As a result, this operating pressure acts on the shaft end of the piston body 2, resists the urging force of the spring 2a, pushes the piston body 2 down, and returns to the port 2f.
comes into contact with the valve seat 3c and stops the inflow of compressed air from the pressure chamber 2c.

In other words, the pusher 4 is the valve seat 3c.
In order for the port 2f to be pushed down again by the working pressure of the pressure chamber 2e to the position of the valve seat 3c that pushed down the valve seat 3c, the working pressure of the pressure chamber 2e compresses the spring 2a, and the compressed position is This corresponds to the fact that the valve seat 3c and the port 2f are in contact with each other. That is, lever 7
When the rotation angle θ of a is set to an arbitrary constant rotation angle θa, the operating pressure Pa in the pressure chamber 2e
is a constant operating pressure determined by the spring characteristics of the spring 2a and the axial projected area of the piston body 2, and the pressure characteristic A of the operating pressure P is as shown in FIG. In addition, the third
In the figure, a indicates the operating point at the rotation angle θa.

In the above action when the sealing surface 4c is in contact with the valve seat 3c, the axial projected area of the sealing surface 4c and the axial projected area of the end surface 6a are the same value, and the pressure chamber 2e is Since the operating pressure is also led to the rear surfaces of the pusher 4 and the cam body 5 (the upper surface portions in the axial direction of the pusher 4 and the cam body 5) through the perforation 4d, the operating pressure is generated in the pressure chamber 2e. However, the operating pressure does not generate an axial pressing force on the pusher 4 and the cam body 5.
As a result, unlike conventional reaction-type pressure control valves, the cam surface 5a does not press the pin 6d with a large force due to the operating pressure, and the pusher 4 and the cam body 5 simply press the pin 6d. It is simply enclosed in a floating state within the pressure chamber 2e, and the cam surface 5
The force acting between a and the pin 6d is only the weak urging force of the spring 4a.

In the above operation of the lever 7a, even if the lever 7a is released, the rotation angle of the lever 7a is required to be fixed and its operating pressure is required to be fixed. The pressure pushes the cam surface 5a upward, and as a result, the reaction force generated on the pin 6d applies a rotational force to the input member 6, causing the coupling ring 7 and the lever 7a to rotate. As mentioned above, the pressure control valve of the present invention is configured so that the operating pressure does not apply a pressing force to the cam surface 5a, so the sealing material 7c is applied to the fitting surface between the coupling ring 7 and the housing 1. The rotation angle of the lever 7a can be sufficiently maintained at a constant level only by the frictional resistance between the coupling ring 7 and the housing 1 due to the presence of the sealing material 7c. All you have to do is adjust the tightness of the material 7c.

Moreover, since the lever 7a and the housing 1 can be arranged in a positional relationship, the pressure control valve of the present invention has a horizontal configuration in which the mounting surface 1h of the housing 1 is mounted on the floor of the vehicle.

As is clear from the above description, since the pressure control valve of the present invention is of a non-reaction type, the surface pressure generated on the cam surface 5a is only the weak urging force of the spring 4a, and this also means that the pressure control valve of the present invention is of a non-reaction type. Furthermore, it is possible to use an inexpensive injection molded material made of synthetic resin for the cam body 5a.

Furthermore, since the pressure control valve of the present invention has a horizontal configuration, parts other than the lever 7a can be mounted on the floor under the driver's seat, making it possible to effectively utilize the space inside the vehicle. be.

Furthermore, since the pressure control valve in the present invention is configured as a non-reaction type, the lever 7a
The fixing of the rotation angle can be as simple as installing the sealing material 7c, so that the manufacturing cost of this pressure control valve can be lowered.

Note that the sealing material 7c also serves as a seal.

[Brief explanation of the drawing]

FIG. 1 shows a side sectional view of a pressure control valve as an embodiment of the present invention.
FIG. 2 shows the cam body 5 in FIG. 1 as viewed from the arrow, and FIG. 3 shows the operating pressure characteristic A in the pressure chamber 2e. The symbols used in the examples are as follows.
1: Housing, 1a: Side plate, 1b and 1f:
Cylinder, 1c, 1d and 1e: Connection hole, 1
g: side wall, 1h: mounting surface, 1i: pin. 2:
Piston body, 2a: Spring, 2b: Cylinder, 2c and 2e: Pressure chamber, 2d: Chamber, 2f:
port. 3: Valve, 3a: Perforation, 3b: Spring, 3c: Valve seat. 4: Pusher, 4a: Spring,
4b: open hole, 4c: sealing surface, 4d: perforation.
5: cam body, 5a: cam surface. 6: Input material, 6a:
End face, 6b: sealing material, 6c: shoulder, 6d: pin,
6e: washer, 6f: bolt. 7: Cup ring,
7a: lever, 7b: serration, 7c: sealing material. P: operating pressure in the pressure chamber 2e, θ: rotation angle of the lever 7a.

Claims (1)

[Claims] 1. A piston body is fitted into a cylinder cut into the housing so as to be able to slide in the axial direction, one axial end face of the piston body is opened to the atmosphere, and applying a biasing force in the axial direction by a first spring; forming a first pressure chamber communicating with a constant pressure source in an axially intermediate portion of the piston body; A second pressure chamber communicating with the load is formed on the axial end surface side, and a port is cut in the piston body between the first pressure chamber and the second pressure chamber, A valve is attached to one axial end of the port and is provided with a second spring biasing force that always tries to close the port, and the valve has the second pressure chamber connected to the atmosphere. A perforation communicating with the second pressure chamber is formed, and a pusher is enclosed in the second pressure chamber, and the pusher selectively closes the perforation and resists the biasing force of the second spring. The valve is selectively pressed, thereby selectively bringing the port into communication, and the pusher is configured to be rotatable about the cylinder axis relative to the pusher; An input material is fitted, a cam surface is cut on the shaft end surface of either the pusher or the input material, and a cam surface is provided on the other of the input material or the pusher to slide on the cam surface. A cam follower is fixedly attached to the pusher, and a sealing surface that selectively closes the perforation in the pusher has an open hole at a shaft end surface of a portion of the input material that fits into the pusher; The outer diameter of the pusher fits into the cylinder, and the chamber on one side and the chamber on the other side in the axial direction of the pusher formed by the fitting communicate with each other through a passage, and both of the chambers form the above-mentioned cylinder. A pressure control valve having the above configuration and forming a second pressure chamber. 2. The pressure control valve according to claim 1, wherein the cam surface is made of a synthetic resin material. 3. A piston body is fitted into the cylinder cut into the housing so as to be able to slide in the axial direction, one axial end surface of the piston body is opened to the atmosphere, and the first spring is applied to the end surface of the piston body. A first pressure chamber is formed in an axially intermediate portion of the piston body and communicates with a constant pressure source, and a first pressure chamber is formed at the other axial end surface of the piston body. a second pressure chamber communicating with the load is formed; a port is cut in the piston body between the first pressure chamber and the second pressure chamber; A valve to which a second spring bias force is applied to constantly close the port is attached to one axial end of the port, and the valve is provided with a hole that communicates the second pressure chamber with the atmosphere. a pusher is disposed in the second pressure chamber, and the pusher selectively closes the perforation and selectively closes the valve against the biasing force of the second spring. the input member is fitted into the pusher so as to be able to rotate around the cylinder axis with respect to the pusher; A cam surface is cut on the shaft end surface of either the pusher or the input material, and a cam follower that slides into contact with the cam surface is fixed on the other of the input material or the pusher. and a sealing surface of the pusher that selectively closes the perforation has an open hole at a shaft end surface of a portion of the input material that fits into the pusher, and the outer diameter of the pusher is: A chamber on one side in the axial direction of the pusher and a chamber on the other side in the axial direction of the pusher that are fitted into the cylinder and formed by the fitting communicate with each other through a passage, and both communicate with the second pressure chamber. and the input material is interlocked with a coupling that is rotatably and slidably fitted to the housing, and the coupling and the housing are fitted together through a friction material. Pressure control valve consisting of. 4. The pressure control valve according to claim 3, wherein the cam surface is made of a synthetic resin material.