JPS6162676A - Brake valve for railway vehicle - Google Patents

Abstract

PURPOSE:To prevent an increase in sliding resistance at a sliding surface between a valve and a valve seat by separating and removing graphite component at the upper surface portion of the valve seat to form a lot of vary small vertical concave portions, and accumulating lubricating oil in the concave portion. CONSTITUTION:A raw material cast iron is subjected to necessary machining, such as boring a supply and discharge hole 4 and the first outlet 3. Just after the surface portion of the machined valve seat 2 is heated up to about 850 deg. by a burner, the surface portion is dipped in quenching oil to be rapidly cooled. The quenching and tempering will cause the surface portion of the valve seat to fall off graphite, and increase hardness of the portion. After the flatness of the surface portion is increased, lapping is performed. At the time of lapping, graphite is removed to form concave portions. The concave portion 20 has a diameter of several mu and a depth of several tens of mu, and lubricating oil is accumulated in the concave portions 20.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used in an automatic air brake system for railway vehicles, and by rotating the handle, air pipes are pressurized and depressurized to perform loosening and braking. This article relates to brake valves for railway vehicles.

[Prior art]

An outline of a conventional general brake valve for railway vehicles will be explained based on FIG. 1.

In Fig. 1, 1 is a main body, and a cast iron valve seat 2 is fixed to the lower part of the main body 1, and a first exhaust hole 3 and a supply/discharge hole 4 are vertically bored in the valve seat 2. has been done. One open end of the first exhaust hole 3 is open to the atmosphere at the bottom of the valve seat 2, and the other open end is located at the center of the upper plane of the valve seat 2.

Further, one open end of the supply/discharge hole 4 is connected to the air pipe BP at the lower part of the valve seat 2.

A rotary valve 7 is rotatably and slidably mounted with its lower surface abutting the upper surface of the valve seat 2, and the rotary valve 7 is provided with a second exhaust hole 9 and an air supply hole 8. . One opening end of the second exhaust hole 9 is located at the center of the lower plane of the swivel valve 7, and the other opening end of the first exhaust hole 3 is located at the center of the lower plane of the swivel valve 7. Located outside the center.

Further, one open end of the air supply hole 8 is located above the rotary valve 7, and the other open end is located outside the center of the lower plane of the rotary valve 7.

A supply chamber 10 is formed facing the upper part of the rotary valve 7, and the supply chamber 10 is constantly communicated with one open end of the air supply hole 8, and is connected to a pressure air source 12 via a pressure regulator 11. .

Further, the lower end of a rotating shaft 6 is fixed to the center of the upper part of the swivel valve 7, and the upper end of the rotating shaft 6 projects upwardly from the main body 1.

A handle 5 is attached to the upper end of the rotary shaft 6, and the handle 5 rotates and slides the rotary valve 7 on the valve seat 2 to select a brake position or a release position.

The relaxed position is the state shown in FIG. 1, in which the other open end of the second exhaust hole 9 is closed and the air supply hole 8 is closed.
This is a position where the other open end of the supply/discharge hole 4 communicates with the other open end of the supply/discharge hole 4 . That is, this loosened position is the air pipe BP
This is the position where the pressure is increased to a predetermined pressure (for example, 5 kg/ci).

The brake position is a position where the other open end of the air supply hole 8 is closed and the other open end of the second exhaust hole 9 communicates with the other open end of the supply/discharge hole 4. That is, this brake position is a position where the air pipe BP is depressurized.

Note that the automatic air brake device that controls the braking force applied to the wheels by operating the handle 5 of the brake valve is well known, so a description thereof will be omitted.

C Problems to be Solved by the Invention] In this brake valve, the rotating valve 7 rotates and slides on the valve seat 2 by operating the handle 5 as described above. The swivel valve 7 is in metal surface contact with the swivel valve 7, and the swivel valve 7 is pressed against the valve seat 2 by air pressure within the supply chamber 10. Therefore, the rotating valve 7
There is considerable sliding resistance between the rotary valve 7 and the valve seat 2, and in order to reduce this sliding resistance, a conventional method has been to interpose grease between the rotary valve 7 and the valve seat 2.

However, only a mere oil film is formed between the rotary valve 7 and the valve seat 2, and the steering wheel 5 during vehicle operation
Because the operation is performed frequently, the number of times the handle is operated (
When this happens, the grease runs out and the sliding surface (the contact surface between the rotary valve 7 and the valve seat 2) wears and seizes, increasing the sliding resistance and hindering handle operation. It was also necessary to carry out maintenance inspections.

[Means for solving problems]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide the brake valve for railway vehicles with ease of handle operation without increasing the sliding resistance between the concave valve 7 and the valve seat 2 even when the number of handle operations increases. The solution includes a first exhaust hole fixed to the lower part of the body, one open end open to the atmosphere and the other open end located in the center of its upper plane, and one open end connected to the air pipe. A cast iron valve seat is provided with a supply/discharge hole whose other open end is located outside the center of the upper plane of the valve seat, and a rotary slide with the lower plane of the valve seat in contact with the upper plane of the valve seat. It is placed movably, one opening end is located at the center of the lower plane, the other opening end of the first exhaust hole is located, and the other opening end is located outside the center of the lower plane. A swivel valve having a second exhaust hole and an air supply hole having one open end located at the upper part and the other open end located outside the center of the lower plane of the swivel valve; and the upper part of the swivel valve. a supply chamber which is formed facing the air supply chamber and is connected to a pressure air source and communicates with one open end of the air supply hole, and whose lower end is fixed to the upper part of the swivel valve and whose upper end protrudes upward from the main body. a rotating shaft, and a handle attached to the upper end of the rotating shaft for rotating and sliding the swivel valve on the valve seat to select a brake position or a release position, and the release position is set to the above-mentioned position. The other opening end of the second exhaust hole is closed, and the other opening end of the air supply hole is in communication with the other opening end of the air supply hole, and the brake position is at the same time as the other opening end of the air supply hole is closed. A brake valve for a railway vehicle, wherein the opening end is closed and the other opening end of the second exhaust hole is in communication with the other opening end of the supply/discharge hole, the graphite component on the upper surface of the valve seat. was separated and removed to form a large number of extremely small recesses in the vertical direction, the means for forming the recesses was heat treatment and subsequent lapping, and lubricating oil was accumulated in the recesses.

[Effect]

According to this method, a large number of extremely small recesses correspond to the parts from which graphite components are removed from the upper surface of a cast iron valve seat, and moreover, they open upward in the vertical direction, and the graphite components are removed from the upper surface of the cast iron valve seat. The lubricating oil prevents an increase in sliding resistance on the sliding surface between the rotary valve and the valve seat. Further, according to the above means, when the cast iron grows, that is, when the cast iron is heated and cooled, pearlite in the structure is decomposed and graphite easily falls off.
The graphite can be easily removed by subsequent lapping.

〔Example〕

Examples of the present invention will be described below.

The basic configuration of the railway vehicle brake valve of the present invention is the same as that shown in FIG.
As shown in a partially enlarged view in FIG. 2, lubricating oil is accumulated in a large number of vertically small recesses 20 formed on the upper surface of the valve seat 2.

The valve seat 2 was formed by the following process.

First, the machined valve seat 2 is machined by performing necessary machining such as drilling the supply and exhaust holes 4 and the first exhaust hole 3 in the cast iron material.
The surface part (the part that comes into contact with the rotating valve) is heated by a burner to approx.
Immediately after heating to 50°C, the valve seat 2 is immersed in quenching oil to be rapidly cooled.Next, the valve seat 2 is heated to about 180°C in an electric furnace, held for about 1 hour, and then gradually cooled to room temperature. This quenching and tempering makes it easier for graphite to fall off and increases the hardness of the valve seat surface. Then, after the surface portion is subjected to strain relief processing to increase the flatness of the surface portion, lapping is performed. During this lapping, the graphite is removed and recesses are formed. Afterwards, the work is completed by cleaning and inspection.

FIG. 2 shows an enlarged view of a part of the surface of the valve seat 2 formed by this operation. 20 is a vertical recess formed by separating and removing graphite in the cast iron structure by heat treatment and lapping, and the diameter (width) of the recess 20 is several microns and the depth is approximately several tens of microns. Lubricating oil is accumulated in a recess 20 on the surface of the valve seat 2.

〔effect〕

With conventional brake valves, the handle resistance increases by approximately 1.5 times when assembled after 10,000 to 50,000 handle operations. It has been confirmed through experiments that the brake valve of the present invention thus formed has almost no change in handle resistance from when assembled even after 100,000 handle operations.

In other words, according to the present invention, even if the handle is operated many times, it is possible to suppress the wear of the abutting part between the rotary valve and the valve seat, and the abutting part does not seize and the sliding of the abutting part is prevented. It is possible to prevent a decrease in handle operability without increasing dynamic resistance, and the life of the brake valve can be extended compared to conventional brake valves.

Another method that seems to be able to solve the above-mentioned conventional problems is as follows: (1) Coating the surface of the valve seat that comes into contact with the rotary valve with Teflon.

(2) A large number of small four parts are formed by machining on the surface of the valve seat that abuts the rotary valve, and lubricating oil is accumulated in the recesses.

Two methods have been considered, and the applicant conducted experiments using these two methods.

However, as a result, in the former (1), when the number of handle operations increases, the coating peels off and air leaks occur, and in the latter (2), depending on the number and position of the recesses formed on the surface, the surface Partial damage occurs and air leaks occur, and with either of the above methods, if the handle is operated many times, the sliding surface seizes and cannot be used for a long period of time.In the end, the above-mentioned conventional problems are not solved. There wasn't.

Compared to these two other means, the present invention provides the effects already described above.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the basic structure of a brake valve for a railway vehicle, and FIG. 2 is a partially enlarged explanatory diagram of the upper surface portion of a valve seat 2 in one embodiment of the present invention.

Claims (1)

[Claims] A first exhaust hole fixed to the lower part of the main body, one opening end of which is open to the atmosphere, and the other opening end of which is located at the center of the upper plane; and one opening end of which is an air pipe. a cast iron valve seat, which is connected to the valve seat and has a supply/discharge hole with the other open end located outside the center of the upper plane of the valve seat; It is rotatably and slidably mounted, one opening end is located at the center of the lower plane, and the other opening end of the first exhaust hole is located outside the center of the lower plane. a swivel valve having a second exhaust hole located therein, and an air supply hole whose one open end is located at its upper part and whose other open end is located outside the center of its lower plane; and the swivel valve. a supply chamber formed facing the upper part of the main body and connected to a pressure air source and communicating with one open end of the air supply hole; a rotating shaft protruding from the rotating shaft; and a handle attached to the upper end of the rotating shaft for rotating and sliding the swivel valve on the valve seat to select a brake position or a release position, the release position being , the other opening end of the second exhaust hole is closed and the other opening end of the air supply hole communicates with the other opening end of the air supply and exhaust hole, and the brake position is a position where the other opening end of the air supply hole communicates with the other opening end of the air supply hole. In the brake valve for a railway vehicle, the other opening end of the second exhaust hole is closed and the other opening end of the second exhaust hole is in communication with the other opening end of the supply/discharge hole, and A brake valve for a railway vehicle, characterized in that a graphite component is separated and removed to form a large number of extremely small recesses in the vertical direction, the means for forming the recesses is heat treatment and subsequent lapping, and lubricating oil is accumulated in the recesses. .