JPH0412857Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a piston type relay valve for air brakes of automobiles. More specifically, it relates to the piston structure of this relay valve.

[Prior Art] Conventionally, this type of air relay valve has been provided between a brake valve and a brake chamber, or between a brake valve and a hydraulic air booster, and in either case, the air relay valve receives signal air from the brake valve. The built-in piston is driven accordingly, and high-pressure air from the air tank is supplied to the brake chamber or air booster.

The signal air from this brake valve ends up at the piston of the air relay valve, so if there is moisture in the piping from the brake valve to the air relay valve, it will remain as accumulated water above the piston.

[Problem that the invention aims to solve] During cold seasons, this accumulated water may freeze and cause the air relay valve to malfunction, so conventionally the air relay valve has been periodically operated to remove this accumulated water. There were problems that needed to be overhauled.

An object of the present invention is to provide a piston structure for an air relay valve that automatically discharges accumulated water in the upper part of the piston, thereby eliminating the need for periodic removal of accumulated water during overhaul.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention will be explained with reference to FIG. 1 corresponding to an embodiment. The present invention has a first chamber 21 communicating with the input port 10, a third chamber 23 communicating with the exhaust port 20, a second chamber 22 communicating with the third chamber 23, and a first chamber 2.
1 and a piston 11 that partitions a first chamber 22 and a second chamber 22 and a third chamber 23 and moves a valve seal 12 in response to signal air from a brake valve. 2
A drain hole 26 is provided that communicates the first and second chambers 22, and a sealing valve 27 is provided in the drain hole 26. This sealing valve 27 is connected to the water drain hole 26
A shaft portion 2 that freely penetrates the drain hole 26 and is longer than the hole length of the drain hole 26.
7a, and sealing valves 27b and 27c which are disposed at both the upper and lower ends of this shaft portion 27a and have an outer diameter larger than the diameter of the drain hole 26.

[Function] When the brake valve is not in operation, as shown in FIG. 1, when signal air does not arrive, the pressure in the first chamber 21 is P ₁
is equal to the pressure P ₂ in the second chamber 22, and therefore, during brake operation when the signal air arrives as shown in FIG. 2, the pressure P ₁ in the first chamber 21 is greater than the pressure P ₂ in the second chamber 22. Therefore, the sealing portion 27b at the upper end seals the drain hole 26.

Also, after the signal air arrives from the brake valve and the piston 11 pushes the valve seal 12 open,
The brake is released and the second and third chambers 22,2
When the high pressure air of No. 3 pushes up the piston 11, the pressure in the second chamber 22 becomes P ₂ as shown in FIG.
is higher than the pressure P ₁ in the first chamber 21, so the sealing portion 27c at the lower end seals the drain hole 26 this time.

Even if water accumulates on the upper part of the piston in the first chamber 21 by repeating this process, the accumulated water enters the second chamber 22 through the drain hole 26, passes through the passage 24, and flows with the exhaust air when the brake is released to the exhaust port. 20 and is discharged to the outside through the exhaust valve 16.

[Example] Next, an example of the present invention will be described in detail based on the drawings. In this example, an air relay valve attached to a hydraulic air booster will be explained.

As shown in FIGS. 1 to 3, 10 is an input port communicating with a brake valve (not shown);
is an exhaust port communicating with the atmosphere. A piston 1 is provided between the input port 10 and the exhaust port 20.
1, a valve seal 12 and their return springs 13 and 14 are provided. The valve seal 12 is seated on the valve seat 15 by a return spring 14. The piston 11 partitions a first chamber 21 communicating with the input port 10 and second and third chambers 22, 23 communicating with the exhaust port 20. The second chamber 22 communicates with the third chamber 23 via a passage 24 . In the second chamber 22 there is a return spring 13
is located in the third chamber 23, and the valve seal 12 is located in the third chamber 23. A passage 24 is provided between the bottom of the second chamber 22 and the center of the third chamber 23. Further, an exhaust valve 16 is provided at the opening of the exhaust port 20. The exhaust valve 16 is made of a rubber valve, and is configured to exhaust air exiting from the exhaust port 20 to the outside with an extremely small pressure difference, but prevent air from entering from outside.

When the piston 11 is not in operation, its lower end is separated from the valve seal 12, and the third chamber 23 communicates with the exhaust port 20. The third chamber 23 has a high pressure delivery port 25 that communicates with a power cylinder (not shown). Also, the third chamber 23 is opened to the high pressure inlet port 28 when the piston 11 operates and pushes down the valve seal 12.
It is now connected to the This port 28 is connected to an air tank (not shown).

The characteristic configuration of the present invention is that the piston 11 has a water drain hole 2 that communicates the first chamber 21 and the second chamber 22.
6 is provided, and this drain hole 26 is provided with a sealing valve 27. This sealing valve 27 consists of a shaft portion 27a and sealing portions 27b and 27c. The outer diameter of the shaft portion 27a is smaller than the inner diameter of the drain hole 26,
Its length is longer than the hole length of the drain hole 26. The sealing portions 27b and 27c are provided at both upper and lower ends of the shaft portion 27a, respectively, and are disk-shaped in this example. The sealing parts 27b and 27c have elastic O-rings 27d and 27e, respectively. O-ring 2
7d and 27e are disc-shaped sealing parts 27b and 27
Glue it into the recess formed on the inner surface of c. The outer diameters of these sealing parts 27b and 27c are larger than the outer diameter of the drain hole 26, and both can seal the drain hole 26.

The operation of the sealing valve 27 having such a configuration will be explained. During brake operation when signal air arrives from the brake valve in the figure, the pressure P ₁ in the first chamber 21 changes to the pressure P 2 in the second chamber 22 as shown in FIG. ₂ .
Since it is larger, the sealing part 27b at the upper end seals the drain hole 26 due to the pressure difference. When the pressure P ₁ in the first chamber 21 becomes greater than the resultant force of the pressure P ₂ in the second chamber 22 and the elastic forces of the return springs 13 and 14, the piston 11 moves downward. When the piston 11 pushes open the valve seal 12, the high pressure inlet port 2
High pressure air flows into the third chamber 23 from 8 and is sent to a power cylinder (not shown) through a high pressure delivery port 25.

Next, when the signal air stops coming from the brake valve, the pressure _P1 in the first chamber balances the resultant force of the pressure _P2 in the second and third chambers and the elastic forces of the return springs 13 and 14. After this state, the pressure P ₂ increases and the piston 11 is pushed back upwards. With the valve seal 12 closed, a desired brake actuation force corresponding to the pressure of _P1 is maintained.

Then the brake is released, for example when fully released the pressure P ₁ becomes atmospheric pressure. Here, as shown in FIG. 3, when the high pressure _P2 from the air tank becomes higher than the pressure _P1 in the first chamber, the sealing valve 27
moves from the bottom to the top, and this time the sealing part 27c at the bottom end
seals the drain hole 26. Further, the piston 11 is pushed back upward by the resultant force of the pressure P ₂ and the elastic forces of the return springs 13 and 14. Along with this, the lower end of the piston 11 separates from the valve seal 12.
The third chamber 23 communicates with the exhaust port 20 and communicates with the atmosphere through the exhaust valve 16, so that the pressure _P2 becomes the atmosphere.

Even if water accumulates in the upper part of the piston in the first chamber 21 by repeating this process, the accumulated water enters the second chamber 22 through the drain hole 26 and enters the third chamber 23 at the bottom through the passage 24. When the brake is released, the exhaust air is discharged from the exhaust port 20 to the outside through the exhaust valve 16.

Although the above example describes an air relay valve attached to a hydraulic air booster, the present invention can of course also be applied to an air relay valve installed between a brake valve and a brake chamber.

[Effects of the invention] As mentioned above, in the past, the accumulated water at the top of the piston had to be drained periodically, but according to the present invention, the accumulated water is automatically drained by the vertical movement of the piston. Water can be drained to the outside through the extraction hole. This prevents the piston from malfunctioning during cold weather even without overhauling.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an air relay valve according to an embodiment of the present invention in a non-operating state. FIG. 2 is a sectional view showing its operating state. FIG. 3 is a sectional view showing the released state. 10...Input port, 11...Piston, 12
... Valve seal, 16 ... Exhaust valve, 20 ... Exhaust port, 21 ... First chamber, 22 ... Second chamber, 23 ... Third chamber, 26 ... Water drain hole, 27
...Sealing valve, 27a...Shaft portion, 27b, 27c...
...Sealing part.

Claims (1)

[Claims for Utility Model Registration] A first chamber communicating with the input port, a third chamber communicating with the exhaust port, a second chamber communicating with the third chamber, the first chamber and the third chamber. In an air relay valve comprising a piston that partitions a second and third chamber and moves a valve seal in response to signal air from a brake valve, a water drain that communicates the first and second chambers with the piston. A hole is provided in the drain hole, and a sealing valve is provided in the drain hole, and the sealing valve includes a shaft portion that freely penetrates the drain hole and is longer than the hole length of the drain hole, and a shaft portion at both upper and lower ends of the shaft portion. and a sealing portion having an outer diameter larger than the hole diameter of the water drain hole.