JPH04317849A - Brake valve - Google Patents

Abstract

PURPOSE:To provide a brake valve capable of reducing the delay of a relay piston side pressure release to a main piston side pressure release at the time of loosening a brake. CONSTITUTION:First valve devices 31, 11A, second valve devices 42, 13A, a main piston 15 operating the first valve devices according to the input from a brake pedal 60 to control the pressure of a first outlet 6, a relay piston 34 receiving the pressure of the first outlet and operating the second valve devices to control the pressure of a second outlet 8, and a spring mechanism for interlocking the main piston with the relay piston are provided. The spring mechanism 55 has a lock mechanism 50 for integrally moving the main piston and the relay piston at the time of moving the main piston in its returning direction in a brake valve working an energizing force for moving the relay piston 34 in the operating direction according to the movement in the operating direction of the main piston 15 on the relay piston 34.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake valve used in an air brake circuit of a vehicle or the like.

0002

2. Description of the Related Art A conventional brake valve of this type is disclosed in Japanese Utility Model Application Laid-Open No. 60-45257. This brake valve includes a spring mechanism that interlocks the main piston and the relay piston, and the spring mechanism applies a biasing force to the relay piston to move the relay piston in the operating direction in response to movement of the main piston in the operating direction. However, even when the brake is released, it acts to move the relay piston in the operating direction, so as shown in characteristic (1) in Figure 3, the main pressure release is on the relay piston side. This causes a delay in loosening relative to the release of pressure on the piston side, which adversely affects the overall brake balance, durability, and braking feel of the car.

0003

The present invention has been made to solve this problem, and provides a brake valve that can reduce the delay in releasing pressure on the relay piston side with respect to releasing pressure on the main piston side when the brake is released. The purpose is to provide

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention is provided with a locking mechanism for integrally moving the main piston and the relay piston when the main piston moves in the return direction.

[0005]

[Operation] In the present invention, when the brake is released, the main piston and the relay piston operate integrally by the locking mechanism, so that the delay in releasing pressure on the relay piston side relative to releasing pressure on the main piston side is reduced.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a valve body,
It is formed by connecting an upper body 2 and a lower body 3, and has a hole 4 penetrating vertically, and a first inlet 5, a first outlet 6, a second inlet 7, and a second outlet on the circumferential surface. 8 is open. The holes 4 are, from above, a first large diameter hole 9, a small diameter hole 10, and a first medium diameter hole 11.
, the second large diameter hole 12, and the second medium diameter hole 13 are continuous. The first inlet 5 opens to the first medium-diameter hole 11, and the first outlet 6 opens to the small-diameter hole 10 and passes through the through hole 12A to the upper part (upper chamber 37) of the second large-diameter hole 12 and the second large-diameter hole 12. It communicates with the bottom side of the large diameter hole 9 of No. 1. The second inlet 7 opens into the second medium diameter hole 13, and the second outlet 8 communicates with the bottom (lower chamber 38) of the second large diameter hole 12.

The first large diameter hole 9 has a retaining ring 1 at its upper end.
4 is fitted into the first large diameter hole 9, and the main piston 15 is slidably fitted into the cylindrical portion 16 of the main piston 15, and a spring 17 is fitted into the first large diameter hole 9.
It is urged toward the retaining ring 14 side and stored. The main piston 15 has a shaft portion 18 extending upward and a shaft portion 19 extending into the small diameter hole 10.A stepped hole 20 opening downward is formed in the shaft portion 19, and the peripheral portion of the lower end thereof is a valve. It is located at 19A. The shaft portion 18 protrudes from the upper end of the hole 4 into the plunger 23 inserted into the central hole 22 of the lid 21, and passes through the plate body 24 and the plate body 24 concentrically with the shaft portion 19 to receive the lower end of the plunger 23. A cylindrical body 25 is held down from above by a bolt and washer 26. This plate body 24 is urged upward by a preloaded spring 27 interposed between it and the bottom of the cylindrical part 16, and the cylindrical body 25 is biased upward by a preloaded spring 27 interposed between it and the bottom of the cylindrical part 16. In the set state, the spring 28 has a free length and is biased upward.

The circumferential portion 11A of the lower surface of the upper end opening of the first medium diameter hole 11 is formed as a valve seat.
A cylindrical valve element 31 with a lower opening is accommodated, which is biased upward by a spring 30 and is seated on and off the valve seat 11A at its upper end periphery. This cylindrical valve body 31 constitutes a first normally closed valve (air supply valve) together with the valve seat 11A, and constitutes a first normally open valve (exhaust valve) together with the valve seat 19A. Reference numeral 32 denotes a spring receiver, which is fitted into the lower part of the first medium diameter hole 11 with a seat 32A interposed therebetween and prevented from coming out by a retaining ring 33. A chamber A is defined through which the inlet 5 of No. 1 opens. The lower end of the cylindrical valve body 31 passes through the spring receiving member 32, and a retainer 31B is fitted to the lower end of the cylindrical valve body 31.

A relay piston 3 is installed in the second large diameter hole 12.
4 is stored with its dish-shaped part 35 slidably fitted and urged upward by a spring 36, and the dish-shaped part 35 is
The inside of the large diameter hole 12 is divided into an upper chamber (relay chamber) 37 and a lower chamber 38. The relay piston 34 has a hollow shaft portion 39 extending upward and a cylindrical shaft portion 40 projecting downward. It extends into the attached hole 20, and the peripheral portion of the lower end of the shaft portion 40 serves as a valve seat 40A. An exhaust passage B is formed in the shaft parts 39 and 40.

A peripheral portion 13A of the lower surface of the upper end opening of the second medium diameter hole 13 is formed as a valve seat, and the second medium diameter hole 13 is biased by a spring 41 so that the upper end peripheral portion 13A of the second medium diameter hole 13 is formed as a valve seat. A cylindrical valve body 42 with openings at the upper and lower ends is accommodated. This cylindrical valve body 42 constitutes a second normally closed valve (air supply valve) together with the valve seat 13A, and constitutes a second normally open valve (exhaust valve) together with the valve seat 40A. Reference numeral 43 denotes a spring receiving member that tightly fits into the exhaust port 13B formed at the lower end of the second medium diameter hole 13, and a chamber in which the second inlet 7 opens is provided in the second medium diameter hole 13. Partition C. The lower end of the cylindrical valve body 42 passes through the spring receiving member 43, and a retainer 44 is fitted to the lower end of the cylindrical valve body 42. A check valve 45 is provided at the exhaust port 13B.
is provided. The inside of this cylindrical valve body 42 becomes an exhaust passage D.

As shown in an enlarged view in FIG. 2, the stepped hole 20 of the shaft portion 19 has an upper step portion 20A and a lower step portion 20B, and accommodates a locking mechanism 50. Lower part 20B of stepped hole 20
A retaining ring 51 is fitted at a position slightly above the retaining ring 51, a block 52 is housed on the retaining ring 51, a plate 53 is interposed between the block 52 and the upper part 20A, and the relay piston 34 The shaft portion 39 passes through this plate 53 and reaches near the top of the stepped hole 20. The shaft portion 39 has a spring receiver 54 fitted to the upper surface of the plate 53 at all times, and a spring 55 is interposed between the spring receiver 54 and the upper bottom of the stepped hole 20. ing. The block 52 has a tapered hole 56 that opens upwardly and downwardly and whose diameter decreases downwardly, and an O-ring 57 is interposed between the tapered hole 56 and the shaft portion 39. Wave washer 58 between 53 and
is intervening. 59 is an air release hole.

The lid 21 described above is attached to the upper end surface of the main body 1 with bolts 59, and supports a brake pedal 60 so as to be movable up and down on a shaft 61. It is in contact with the upper surface of the plunger 23.

When the brake pedal 60 is depressed, a downward force is applied to the plunger 23 via the rolling roll 62, and this downward force is applied via the spring 27 (if the depression angle is above a predetermined value, the downward force acts on the plunger 23). 28), acting on the main piston 15, the main piston 15 descends against the spring force of the spring 17, the valve seat 19A seats on the upper surface of the cylindrical valve body 31, and pushes down the cylindrical valve body 31; As a result, the first normally closed valve opens and the first normally open valve closes, blocking the first outlet 6 from the exhaust port 13A, and connecting the first inlet 5 to the chamber A and the small diameter It communicates with the first outlet 6 through the hole 10 . Therefore, compressed air supplied from a compressed air storage tank (not shown) to the first inlet 5 is supplied from the first outlet 6 to a brake operating device (not shown).

A portion of the compressed air supplied to the first outlet 6 is supplied to the upper chamber 27 through the through hole 12A, so that the relay piston 34 is moved under the pressure of this compressed air and the action of the spring 55. The valve seat 40A seats on the upper surface of the cylindrical valve body 42 and pushes down the cylindrical valve body 42, thereby opening the second normally closed valve and closing the second normally open valve. And the second
The second inlet 7 is blocked from the exhaust port 13B.
communicates with the second outlet 8 through the chamber C and the lower chamber 38. Therefore, the compressed air supplied from the compressed air storage tank (not shown) to the second inlet 7 is supplied from the second outlet 8 to the brake operating device (not shown).

When the brake pedal 60 is released, the spring force of the spring 17 and the outlet pressure of the first outlet 6 cause the main piston 15 to rise toward the position shown, and the first normally closed valve closes. At the same time, the first normally open valve opens and the first outlet 6
is blocked from the first inlet 5 and the exhaust path B
and D to communicate with the exhaust port 13B. When the outlet pressure of the first outlet 6 decreases, the pressure in the upper chamber (relay chamber) 37 also decreases, so the relay piston 34 also rises due to the spring force of the spring 36, and the second normally closed valve closes. The second normally open valve is opened, and the second outlet 8 is blocked from the second inlet 7 and communicates with the exhaust port 13B through the exhaust path D.

At the moment when the main piston 15 rises, the main piston 15 moves upward relative to the shaft portion 39 of the relay piston 34, and the O-ring 57 bites into the tapered hole 56 and is compressed in the radial direction. Therefore, a wedge effect is created by the O-ring 57 and the tapered surface, and this wedge effect causes the main piston 15 and the relay piston 34 to become integrated, so that they both rise at the same time.

In this way, in this embodiment, the main piston 1
When the relay piston 5 and the relay piston 34 are activated, no resistance is given to their operation, but when the piston returns, a mechanism 50 is provided that locks the relay piston 34 to the main piston 15, as shown in FIG. 3 (1). When the brake is released, a delay in pressure release on the relay piston side relative to pressure release on the main piston side can be prevented.

Note that the wedge effect is canceled when the brake pedal 60 is depressed. That is, the brake pedal 6
0, the main piston 15 is connected to the relay piston 3.
This is because it moves downward relative to the shaft portion 39 of No. 4. Further, the wedge effect is gradually canceled by pushing back the wave washer 58 by the elastic restoring force of the O-ring 57 when the non-operating state continues for a while.

[0020]

Effects of the Invention As explained above, in the present invention, the main piston and the relay piston are connected via a locking mechanism that exhibits a locking action when the main piston returns, so that when the brake is released, pressure on the main piston side is not released. Delays in pressure release on the relay piston side can be prevented.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the locking mechanism in the above embodiment.

FIG. 3 is a characteristic diagram of the brake pedal showing the relationship between the brake depression angle and the discharge pressure.

[Explanation of symbols]

1 Valve body 4 Hole 5 First entrance 6 First exit 7 Second entrance 8 Second exit 13B Exhaust port 15 Main piston 17, 27, 28 spring 20 Stepped hole 21 Lid 31, 42 Cylindrical valve body 34 Relay piston 36 spring 50 Lock mechanism 52 block 53 board 54 Spring receiver 55 Spring 56 Tapered hole 57 O-ring 58 Wave washer 60 Brake pedal

Claims (1)

[Claims] Claim 1: A first valve device that connects and blocks the first outlet with the first inlet and the exhaust port, and a second valve device that connects and blocks the second outlet with the second inlet and the exhaust port. and the first valve in response to input from the brake pedal.
a main piston that operates a valve device to control the pressure at the first outlet; a relay piston that receives the pressure at the first outlet and operates a second valve device to control the pressure at the second outlet; The brake valve includes a spring mechanism that interlocks a main piston and a relay piston, and the spring mechanism applies a biasing force to the relay piston to move the relay piston in the operating direction in response to movement of the main piston in the operating direction. A brake valve provided with a locking mechanism that moves the main piston and the relay piston together when the main piston moves in the return direction.