JPH0346342B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is based on a patent application published under patent number 1986-73464.
This invention relates to an improvement of the brake device (hereinafter referred to as the conventional device) described in the specification of the No. 1, particularly to an improvement of the load/air brake control mechanism included in this device.

Although the structure and operation of this conventional device are detailed in the above specification, the parts related to the present invention can be summarized as follows.

As shown in FIG. 6 of the above specification, this device is comprised of a brake pipe 20, a brake cylinder 1, a control valve 27, a switching valve 22, and a reverse valve 26.

The brake pipe 20 is installed through the vehicle and is normally filled to a constant standard pressure value.

As shown in FIG. 1, the brake cylinder 1 has an output piston 9 (referred to as a large piston in the above specification), and a first chamber 1 on the left side thereof.
A second chamber 11 is formed on the right side of 0, and when the pressure in the chamber 11 becomes lower than the pressure in the chamber 10, a braking force corresponding to the pressure difference is generated.

The control valve 27 includes an exhaust passage 211 connected to the switching valve 22 via the exhaust pipe 21, and when the brake pipe 20 is filled to the above-mentioned standard pressure value,
Connect chambers 10 and 11 together to brake pipe 20,
When the pressure in the brake pipe 20 is reduced, the pressure in the first chamber 10 is confined so as not to be reduced, and the pressure in the second chamber is
The chamber 11 is connected to the exhaust passage 211.

The switching valve 22 connects the exhaust passage 211 directly to the atmosphere when the vehicle is loaded, and closes the connection when the vehicle is empty.

The reverse valve 26 is installed at the end of the branch pipe 21a of the exhaust pipe 21, and has a built-in valve pressed by a spring.
During the period when the pressure in the tube 21a is above the pressure selected by the force of its spring, the pressurized air in the tube 21a is vented to the atmosphere.

This device is composed of the above-mentioned parts and operates as follows in response to changes in brake pipe pressure.

When the brake pipe 20 is filled to the standard pressure value, the pressure on both sides of the output piston 9 of the brake cylinder 1 is the same, so no output is generated and the brakes of the vehicle are released.

When the pressure in the brake pipe 20 is reduced, the pressure in the first chamber 10 remains approximately at the initial standard pressure value, and the pressure in the second chamber 11
is connected to the exhaust passage. At this time, when the vehicle is loaded, the exhaust passage 211 is connected to the atmosphere via the pipe 21 and the switching valve 22, so the second chamber 11 drops to atmospheric pressure, and the pressure difference on both sides of the piston 9 is It reaches its maximum and the loading vehicle braking force is generated.

However, when the vehicle is empty, the exhaust passage 21
1 does not drop below the constant pressure selected by the spring of the reverse valve 26, the selected pressure remains in the second chamber 11, and the pressure difference on both sides of the piston 9 becomes small. , an empty car brake force is generated.

In this way, the braking force applied to the vehicle is controlled in two stages, strong and weak, depending on the state of the loaded load, thereby preventing the wheels from sliding due to excessive braking force when the vehicle is empty.

However, this conventional device has the following problems. The above-mentioned standard brake pipe pressure value differs depending on the railway, and for example, it is set at 5 kg/cm ² on some railways and 7 kg/cm ² on other railways.

The higher this standard pressure value is, the greater the output of the piston 9 will be.
Since the residual pressure of No. 1 is kept constant by the check valve 26, the ratio between the loaded car braking force and the empty car braking force changes depending on the standard pressure value.

Therefore, if the reverse valve 26 is set in accordance with a low standard pressure value, there is a risk that the empty car braking force will be excessive and wheel slippage will occur when used on a railway that uses a high standard pressure value. arise. The reason why such a problem occurs is that the pressure value set by the reverse valve 26 is fixed at a constant value.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a brake device that can maintain a constant ratio between the braking force of a loaded vehicle and the braking force of an empty vehicle even if the standard pressure values of the brake pipes are different.

In order to solve this problem, in the present invention, the above-mentioned reverse valve is equipped with a pressing piston that generates a pressing force according to the standard pressure value of the brake pipe, and a pressing piston that generates a pressing force according to the standard pressure value of the brake pipe, and a pressure piston that applies the pressing force and the pressure of the exhaust passage to both sides, respectively. Accordingly, the structure includes a disc valve that controls the connection between the exhaust passage and the atmosphere.

By using a reverse valve with this structure, the residual pressure in the second chamber when braking an empty car increases in proportion to the standard pressure value of the brake pipe, so the ratio between the braking force of a loaded car and the braking force of an empty car is always constant. becomes constant, and the above-mentioned problems are completely solved.

Next, one embodiment of the present invention will be described based on the drawings. As shown in the accompanying drawings, this air-load brake control device is comprised of a brake pipe 20, a brake cylinder 1, a control valve 45, a switching valve 31, and a check valve 23.

This device differs from the conventional device described above in that a passage 171a communicating with the first chamber 10 is newly installed in the brake cylinder 1, and that the reverse valve 23 has a completely new structure. It is.

The reverse valve 23 includes a pressing piston 25 and a disc valve 24, and the upper chamber of the piston 25 is connected to a pipe 22,
It communicates with the first chamber 10 of the brake cylinder 1 through the passage 171a, and the disc valve 24 is pushed by the pressing piston 25 and normally seats on the valve seat 29, and the exhaust passage 211
Communication from the exhaust hole 30 via the pipe 21 and passages 27 and 28 is blocked.

Note that the reverse valve 23 is provided with an exhaust promoting section including a membrane plate valve 37, but this portion will be described later as it is not directly related to the gist of the present invention.

Next, the operation of this device will be explained.

When the brake pipe 20 is filled to a constant standard pressure value, the first chamber 10 and the second chamber 11 of the brake cylinder 1 are controlled by the control valve 45, as detailed in the above-mentioned specification. Filled with brake pipe pressure, the third chamber 8 is evacuated, the output piston 9 is pushed by the release spring 15 to the shown release position, and the brakes of the vehicle are released.

When the brake pipe 20 is depressurized, the control valve 45 is activated, and first the communication between the chambers 10 and 11 and the brake pipe 20 is cut off, and while the chambers 10 and 11 remain in communication, a portion of the air is transferred to the third chamber. The piston 9 is moved to the right by the pressure in the chamber 8 and assumes the braking position. When the rightward movement of the piston 9 is completed, the pressurized air in the first chamber 10 is confined so that it does not flow out.
At the same time, the second chamber 11 is connected to the exhaust passage 211.

Since the volume of the chamber 8 is small and its pressure is limited to a low value, the pressure drop in the chamber 10 during the above operation is extremely small and is maintained close to the initial standard pressure value, and the pressure is passage 171a,
The pressure is transmitted through the pipe 22 to the upper chamber of the pressure piston 25 of the check valve 23.

When the vehicle is loaded, the switching valve 31
The internal passage connects the pipe 32 to the atmosphere as shown by the solid line, so the pressurized air flowing into the exhaust passage 211 from the second chamber 10 flows through the pipe 21, the passage 27, and the throttle 3.
3, the pipe 32 and the switching valve 31 before being released into the atmosphere.

Therefore, the pressure in the second chamber 11 drops to atmospheric pressure,
The pressure difference between chambers 10 and 11 becomes maximum, and the load braking force is transmitted to the vehicle.

However, when the vehicle is in an empty state, the internal passage of the switching valve 31 takes the position shown by the dotted line, and communication between the pipe 32 and the atmosphere is cut off. Therefore, the pressure air in the exhaust passage 211 is transferred to the pipe 21 and the passage 2.
7 and 28, it reaches the lower surface of the disc valve 24, pushes up the disc valve 24, and is exhausted to the atmosphere through the exhaust hole 30. Due to this exhaust, the pressure on the lower surface of the disc valve 24 decreases, and when the force pushing the disc valve 24 upward becomes smaller than the pressing force of the pressing piston 25, the valve 2
4 is seated on the valve seat 29, and is connected to the exhaust passage 211 and the second
A pressure proportional to the pressing force of the piston 25 remains in the chamber 11.

Due to this pressure remaining in the second chamber 11, the pressure difference acting on the piston 9 becomes smaller than in the case of a loaded state, and an empty braking force is transmitted to the vehicle. Since the pressing force of the pressing piston 25 increases in proportion to the standard pressure value of the brake pipe, the residual pressure in the chamber 11 also increases in proportion to the standard pressure value.
The ratio of the loaded vehicle braking force to the empty vehicle braking force is always constant, and the problems with conventional devices mentioned at the beginning are completely solved.

Incidentally, the exhaust promoting section attached to the reverse valve 23 operates as follows when the load of the vehicle increases slightly from the empty state and the exhaust capacity by the switching valve 31 is relatively small.

In this case, due to the effect of the throttle 33, the pressure in the lower chamber 40 of the membrane plate valve 37 decreases faster than the pressure in the upper chamber 36. Therefore, the membrane plate valve 37 moves downward due to the pressure difference, and the valve seat 43 formed on its upper surface is separated.
Pressure air in the exhaust passage 211 is supplied to the pipe 21, the passage 27,
41, chamber 42, and exhaust hole 44, and are rapidly exhausted to the atmosphere.

[Brief explanation of drawings]

The attached drawings are action explanatory diagrams showing one embodiment of the present invention. 1... Brake cylinder, 9... Output piston, 10... First chamber, 11... Second chamber, 20...
Brake pipe, 23... Check valve, 24... Disc valve,
25...Press piston, 31...Switching valve, 211
...exhaust passage.

Claims (1)

[Scope of Claims] 1. (a) A brake pipe normally filled with a constant standard pressure value; (b) A first chamber and a second chamber formed on both sides, and depending on the pressure difference between the two chambers. (c) a brake cylinder including an output piston that generates a braking force; (d) a control valve that operates to connect the second chamber to the exhaust passage; and (d) a switching valve that senses that the vehicle is in an empty state and closes the connection between the exhaust passage and the atmosphere. (e) a check valve that connects the exhaust passage to the atmosphere during a period when the pressure in the exhaust passage is equal to or higher than a selected value; A structure including a pressing piston that generates a pressing force according to the standard pressure value of the above, and a disc valve that receives the pressing force and the pressure of the exhaust passage on both sides to control the connection between the exhaust passage and the atmosphere. Load/air brake control system for railway vehicles.