JPH0443021B2 - - Google Patents

Abstract

PURPOSE:To prevent leakage and to improve the controllability by providing a path communicating between balance chambers above/below of a piston and a brake tube chamber in the piston while arranging a check valve having the forward direction toward the brake tube chamber in the communication path. CONSTITUTION:A balance chamber 23 is formed while facing against the upper side of piston 22 for balance delivery valve 20, and a brake tube chamber 24 is formed while facing against the under side of the piston 22. A path 28 communicating between the balance chamber 23 and the brake tube chamber 24 is formed in the piston 22. A check valve 29 is arranged in said path 28. Upon bringing the brake valve to overlapping position, when braking, the pressure in the brake tube BP is higher than that in the balance air sump ER but the check valve 29 will block leakage from the brake tube chamber 24 to the balance chamber. Consequently, the pressure in the brake tube BP upon finish of discharge of said valve 20 to seat the discharge valve 26 in the valve seat 40 is approximately same with that in the balance air sump ER. It will just match with the pressure level commanded by the operator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a balanced discharge valve for a railway vehicle, which is used in an air brake system of a railway vehicle and relays pressure reduction to a brake pipe.

[Conventional technology]

The air brake system for a railway vehicle using the conventional balanced discharge valve A is shown in Figure 4, where BV is the brake valve, ER is the balanced air reservoir, BP is the brake pipe, CV is control valve, BC
is the brake cylinder and AR is the air reservoir. This brake device is operated by switching the brake valve BV using the handle 1. The configuration of the balanced discharge valve A and the brake valve BV is as shown in FIG. The brake valve BV can be operated in four positions: a relaxed position a, an overlapping position b, a brake position c, and an emergency brake position d.

(a) Figure 5 shows the state in which the brake valve BV is in the released position a, and the brake is released. In this state, pressurized air adjusted to a predetermined pressure (usually 5 kg/cm ² ) is supplied from the source air reservoir (not shown) to port 2 via supply valve FV, and this air is supplied from port 3 to balancing chamber 6 and To the balancing air reservoir ER, and from port 4 to brake pipe chamber 7 and brake pipe
Supplied to BP. At this time, the exhaust valve 8 is pressed against the valve seat 10 by its own weight and the urging force of the spring 9, thereby closing the space between the brake pipe chamber 7 and the exhaust chamber 11. The state in which the brake pipe BP is pressurized to a predetermined pressure (usually 5 kg/cm ² ) is the relaxed state, and the control valve CV is operated to release the brake cylinder BC, and the air reservoir AR is released to a predetermined level. It is pressurized. The brake is in a relaxed state with the brake cylinder BC being exhausted.

(b) When applying the brake from this relaxed (operating) state, first set the brake valve BV to brake position c and reduce the pressure in the balance air reservoir ER, and when the amount of pressure reduction reaches the desired value, brake Valve BV
This is done by setting the overlapping position b to the overlapping position b.

In other words, the brake valve BV is moved to the brake position c.
Then port 4 is closed and the balancing air reservoir
ER, the balance chamber 6 of the balance discharge valve A is the exhaust chamber 11
It also communicates with the exhaust port _EX through a small passage inside the brake valve BV. This creates a balancing air reservoir.
Since the pressure in the ER and the balance chamber 6 is reduced, the piston 12 rises due to the pressure difference between the upper and lower sides, and the exhaust valve 8
is removed from the valve seat 10 and communicates the brake pipe chamber 7 with the exhaust chamber 11, whereby the brake pipe BP
is depressurized via the exhaust chamber 11. At this time,
When the amount of pressure reduction in the balancing air reservoir ER of a constant capacity is as desired by the driver, the brake valve BV is moved to the overlap position b. At overlap position b, ports 3 and 4 are closed and only port 5 is connected to exhaust port _EX , so brake pipe BP, which was being depressurized at brake position c, is almost the same as the balance air reservoir ER. When the brake pressure reaches the pressure, the piston 12 descends due to its own weight, the exhaust valve 8 closes, and the pressure reduction in the brake pipe BP is stopped.

This pressure reduction in the brake pipe BP causes the control valve CV to
However, the air in the air reservoir AR is adjusted to a pressure corresponding to the amount of pressure reduction in the brake pipe BP, and is supplied to the brake cylinder BC to apply the brakes to the vehicle.

(c) When releasing this brake, brake valve BV
loosen and return to position a. This returns to the state of (a) above.

In addition, at this time of loosening, since the capacity of the balance air reservoir ER is smaller than that of the brake pipe BP,
The pressure in the balancing chamber 6 increases faster than in the brake pipe chamber 7, the piston 12 descends, and air flows from the balancing chamber 6 into the brake pipe chamber 7 through the leak groove 14 at the lower end of the bushing 13, causing the piston 12 to rise. The pressure difference between the top and bottom surfaces is balanced.

(d) When operating the emergency brake in the above-mentioned relaxed (operating) state, set the brake valve BV to the emergency brake position d.

At this time, the air in the brake pipe chamber 7 of the brake pipe BP and the balance discharge valve A is
The air is rapidly exhausted from the exhaust port _EX after passing through a large passage inside the BV. As a result, the pressure of the balancing air reservoir ER confined in the balancing chamber 6 causes the piston 12 to move downward by compressing the spring 9 while keeping the exhaust valve 8 seated. The leak groove 14 opens, and air from the balance air reservoir ER flows into the brake pipe chamber 7 from the leak groove 14.
It is exhausted from the brake valve BV together with the air from the brake pipe BP.

This sudden pressure reduction in the brake pipe BP causes the control valve CV to suddenly apply the brake, supplying high pressure air to the brake cylinder BC, and applying the emergency brake to the vehicle.

[Problem that the invention seeks to solve]

The piston 12 of the conventional balanced discharge valve A has a fifth
As shown in the figure, since it has a ring 15 on the outer periphery and slides on the inside of the bush 13, the sealing between the balance chambers 6 above and below the piston and the brake pipe chamber 7 is poor. This causes the following problems.

At the time of brake command (when reducing the balance air reservoir ER pressure),
When the brake valve RV is set to brake position c and the balance air reservoir ER is reduced to the desired pressure, for example, pressure P ₁ (shown at t ₃ in Figure 6), let's maintain the pressure P ₁ of the balance air reservoir ER. Assuming that the brake valve BV is at the overlap position b, the pressure in the brake pipe _BP is greater than the pressure in the balancing air reservoir _ER , so
The air in the brake pipe BP during decompression reaches the piston 12.
Flows into the balancing chamber 6 from the outer periphery. Balance air reservoir ER
Since is a constant volume, the pressure is increased by the incoming air.
_PER increases. Therefore, when the exhaust operation of the balance discharge valve A is completed and the exhaust valve 8 is seated, the pressure in the balance air reservoir _ER and the pressure in the brake pipe _BP are the same as when the driver initially reduced the pressure. The pressure _P2 becomes higher than the pressure _P1 of the set balance air reservoir ER. In other words, since the pressure reduction amount △P ₁ of the balance air reservoir ER is the brake command, according to this conventional balanced discharge valve A, the command (pressure reduction amount △P ₂ ) can only be obtained. This state is shown in FIG. In the same figure, t ₁ is the brake valve
When the BV is changed from the relaxed position to the brake position c,
t ₄ is the point in time when the pressures P _BP and P _ER become equal.

Therefore, the amount of pressure increase in the balance air reservoir ER (P ₂ − P ₁ )
It is necessary to perform predictive control to increase the amount of pressure reduction in the balance air reservoir ER by an amount that takes into account the expected increase in pressure, or correction control to repeat the pressure reduction in the balance air reservoir ER two or three times. Since the amount varies depending on the length of the brake pipe BP (which varies depending on the number of vehicles in the train) and the amount of pressure reduction in the balance air reservoir ER, the predictive control and correction control require considerable skill.

[Means for solving problems]

Therefore, the means of the present invention for solving the above-mentioned conventional problems includes: a piston movably provided in a main body; and a balancing chamber formed facing one side of the piston and connected to a balancing air reservoir. a brake pipe chamber formed facing the other side of the piston and connected to the brake pipe; an exhaust chamber formed adjacent to the brake pipe chamber; and a brake pipe chamber slidable toward the brake pipe chamber side of the piston. and an exhaust valve that is fitted into the piston and biased by a spring to open and close between the brake pipe chamber and the exhaust chamber, wherein the balance chamber and the brake pipe chamber are disposed within the piston. providing a communication path that communicates with the brake pipe chamber, and providing a check valve in the communication path with the direction toward the brake pipe chamber as the forward direction,
The balance chamber side of the piston is made to protrude and is slidably fitted into the main body, and a back pressure chamber is formed at the end of the fitting part, and the back pressure chamber is communicated with the exhaust chamber and its effective area is An airtight membrane plate is provided, which is formed to have approximately the same effective area as the valve seat on which the exhaust valve is seated and removed, and whose inner edge is fixed to the outer periphery of the piston, and whose outer edge is fixed to the main body.

[Effect]

According to this technical means, when applied to the same conventional brake device, the brake valve is placed in the braking position, the balance air reservoir is depressurized, and when the desired amount of pressure reduction is reached, the brake valve is placed in the overlapping position. Although the pressure in the brake pipe is greater than the pressure in the joint air reservoir,
Since a membrane plate is provided around the piston's outer circumference, there is no leakage from the brake pipe chamber to the balance chamber through the piston's outer circumference, and the check valve is connected in the opposite direction to the balance chamber. There is no leakage from the brake pipe chamber to the balance chamber due to air flow. Therefore, when the exhaust operation of this balanced discharge valve is completed and the exhaust valve is seated on the valve seat, the pressure in the brake pipe is approximately the same as the pressure in the balanced air reservoir. The pressure is as commanded by the driver (see Figure 3).

〔Example〕

A first embodiment is shown in FIG. In the same figure, 2
0 is a balanced discharge valve, 21 is a main body of the balanced discharge valve, and a piston 22 is provided within the main body 21 so as to be movable up and down. A balancing chamber 23 is formed facing the upper side of the piston 22, a brake pipe chamber 24 is formed facing the lower side of the piston 22, and an exhaust chamber 25 is formed adjacent to the lower side of the brake pipe chamber 24. ing.

The piston 22 supports an exhaust valve 26 at the bottom thereof,
It has a fitting part 27 into the back pressure chamber 35 at the upper end, and a communication passage 28 connecting the balance chamber 23 and the brake pipe chamber 24 is bored inside.
A check valve 29 whose forward direction is the direction from the brake pipe chamber 24 to the brake pipe chamber 24 is provided. In the figure, reference numeral 30 denotes a weak spring, which is provided between the intermediate body 31 and the check valve 29. 32 is a strong spring, which connects the intermediate body 31 and the exhaust valve 26.
The exhaust valve 26 is stopped by a retaining ring 33 to prevent it from slipping out downward.
A through hole serving as the communication path 28 is bored in the intermediate body 31 and the exhaust valve 26. Further, a membrane plate 34 is provided between the outer periphery of the piston 22 and the inner surface of the inner hole through which the piston moves up and down to maintain airtightness. That is, the membrane plate 34 is disk-shaped with an inner hole, and its inner edge is hermetically fitted into a groove on the outer periphery of the piston 22, and its outer edge is airtightly clamped to the main body side. Therefore, air does not move between the balancing chamber 23 and the brake pipe chamber 24 through between the outer periphery of the piston 22 and the inner bore of the main body.

The fitting portion 27 at the upper end of the piston 22 is formed into a piston shape, and a cylindrical back pressure chamber 35 is formed corresponding thereto. This back pressure chamber 35 is the passage 3
It is connected to the exhaust chamber 25 via 6. In the diagram, 3
7 is a seal ring, and 38 is a bush.

Exhaust valve 2 supported at the bottom of piston 22
6 is adapted to sit on a valve seat 40 provided with a valve hole 39 bored across the pipes between the brake pipe chamber 24 and the exhaust chamber 25. In the figure, 41 is a seal ring.

The effective area S ₂ on which the air pressure of the back pressure chamber 35 acts on the fitting part 27 is the effective area of the valve seat 40 of the exhaust valve 26.
It is determined to be approximately equal to S ₁ .

In addition, 42 in the figure is a return spring, which is used to ensure that the piston 22 is in the raised position when air is first introduced and does not constantly discharge air, but since the piston has its own weight, it can be omitted. good.

FIG. 2 shows a second embodiment. In the same figure, parts equivalent to those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. This balanced discharge valve 20a is different from the balanced discharge valve 20 shown in FIG.
The point is that one spring 50 is provided instead of the intermediate body 31. Therefore, in this balanced discharge valve 20a, the opening pressure of the check valve 29 is slightly different.

Balanced discharge valve 20 of these first and second embodiments,
20a is generally used in place of the balanced discharge valve A of the brake device shown in FIGS. 4 and 5. In other words, the balance room 23
is connected to the balancing air reservoir ER and port 3 of the brake valve BV, the brake pipe chamber 24 is connected to the brake pipe BP and port 4 of the brake valve BV, and the exhaust chamber 2
5 and back pressure chamber 35 are connected to port 5 of brake valve BV. Note that, unlike the connection state shown in FIGS. 4 and 5, the balance air reservoir ER and the balance discharge valve 20,
Connect 20a and brake pipe BP in series,
There may also be a usage state in which air is supplied to the brake pipe BP via the check valve 29.

The balanced discharge valves 20 and 20a both operate in substantially the same manner as the conventional balanced discharge valve A. However, as shown in Figure 3, the brake valve BV is
At t ₁ , the pressure in the balance air chamber 23 and the balance air reservoir _ER is changed from the release position a to the brake position _c.
At the time t ₃ when the desired pressure reduction amount △P ₁ is reached,
When the brake valve BV is set at the overlap position b, the pressure in the brake pipe chamber 24 and the brake pipe BP is lower than the pressure in the balance air chamber 23 and the balance air reservoir _ER , P _BP.
Although this is larger, there is no leakage between the two chambers 23 and 24 due to the membrane plate 34 provided, and the communication passage 28 is also closed by a check valve 29. Therefore, when the exhaust valve 26, which is opened due to a pressure difference, is closed due to pressure equilibrium, the pressure PBP in the brake pipe chamber 24 and the brake pipe _BP is initially equal to the pressure PBP in the balance air chamber 23 and the balance air reservoir. Since the ER pressure P is very close to the pressure P ₁ corresponding to the desired pressure reduction amount △P ₁ from _{the ER} , and the differential pressure is always constant, it is considered to be as instructed by the driver. be able to. In other words, the reason why the pressures _PER and _PBP do not match is due to the weight of the piston 22 and the biasing action of the spring 42, and the differential pressure generated by this is caused by the pressure difference in the brake pipe.
This is because it is constant regardless of the length of BP or the amount of pressure reduction in the balance air reservoir ER.

The check valve 29 opens when the air pressure on the balance air chamber 23 side becomes higher than the air pressure on the brake pipe chamber 24 side, and this almost corresponds to the leak groove 14 of the conventional balance discharge valve A. It is something.

〔Effect of the invention〕

According to the present invention, when operating the service brake by reducing the pressure in the balancing air reservoir and the balancing chamber by operating the brake valve, the pressure in the balancing air reservoir is proportional to the length of the brake pipe and the amount of pressure reduction in the balancing air reservoir. Since the pressure is reduced according to the driver's command regardless of the degree, there is no need for predictive control or correction control that was required in the past, and the effect that brake operation does not require a high degree of skill is achieved.

Further, according to the present invention, the following unique effects can be obtained.

Another possible solution to the above-mentioned conventional problems is to use a balanced discharge valve 60 as shown in FIG. This is a balanced discharge valve 60 having a structure excluding the fitting part 27 and the back pressure chamber 35 of the balanced discharge valve 20a of the present invention shown in FIG. This alternative means
In a relaxed state where the pressure in the balance air reservoir _ER and the pressure in the brake pipe _BP are at a predetermined pressure (usually 5 kg/cm ² ), the exhaust valve 26 is opened by the pressure in the brake pipe _BP . It is pressed against the valve seat 40, and the force is (P _BP ×S ₁ ). Therefore, during braking (when ER pressure is reduced), the exhaust valve does not open immediately due to the pressure difference between the brake pipe pressure P _BP and the equilibrium air reservoir pressure P _ER , but the piston 22 is raised due to the pressure difference. The pressure reduction in the brake pipe BP will not start unless the force applied exceeds the value equivalent to (P _BP ×S ₁ ). In other words, as shown in Figure 8,
The exhaust valve 26 opens after the pressure difference between the brake pipe pressure P _BP and the equilibrium air reservoir pressure P _ER exceeds △P.
Since the brakes are activated, the balance air reservoir
The brake is activated from time _t2 , which is a time Δt later than the time _t1 when the ER exhaust starts.

In contrast to this other means, the means of the present invention is provided with a fitting portion 27 and a back pressure chamber 35, thereby canceling out the force pressing the exhaust valve 26 against the valve seat 40, as shown in FIG. The effect is that there is no delay (brake activation delay) of the time Δt shown.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a first embodiment of the present invention, FIG. 2 is a vertical cross-sectional view showing a schematic configuration of a second embodiment of the present invention, and FIG. 4th graph showing changes in brake pipe pressure P _BP and balance air reservoir pressure P _ER over time when the example is used in place of the balance discharge valve of a conventional brake system and a service brake is operated. The figure is a piping diagram showing the general configuration of a conventional brake device, FIG. A graph corresponding to FIG. 3 of the conventional brake device, FIG. 7 is a vertical sectional view of a balanced discharge valve shown as another means different from the present invention, and FIG. 8 is a graph corresponding to FIG. This is a graph corresponding to the figure. BV...Brake valve, ER...Balancing air reservoir, BP
... Brake pipe, CV ... Control valve, BC ... Brake cylinder, 20, 20a ... Balanced discharge valve, 2
1...Body, 22...Piston, 23...Balance chamber, 24...Brake pipe chamber, 25...Exhaust chamber, 2
6... Exhaust valve, 27... Fitting part, 28... Communication path, 29... Check valve, 34... Membrane plate, 35... Back pressure chamber, 40... Valve seat.

Claims (1)

[Claims] 1. A piston movably provided within the main body;
a balancing chamber formed facing one side of the piston and connected to a balancing air reservoir; a brake pipe chamber formed facing the other side of the piston and connected to a brake pipe; and the brake pipe chamber. an exhaust chamber formed adjacent to the piston, and an exhaust valve slidably fitted into the brake pipe chamber side of the piston and biased by a spring to open and close between the brake pipe chamber and the exhaust chamber. In the balanced discharge valve for a railway vehicle, a communication path is provided in the piston to communicate the balance chamber and the brake pipe chamber, and the communication path is provided with a check whose forward direction is toward the brake pipe chamber. Provide a valve;
The balance chamber side of the piston is made to protrude and is slidably fitted into the main body, and a back pressure chamber is formed at the end of the fitting part, and the back pressure chamber is communicated with the exhaust chamber and its effective area is The exhaust valve is characterized by being provided with an airtight membrane plate formed to have approximately the same effective area as a valve seat on which the exhaust valve is seated and removed, and whose inner edge is fixed to the outer periphery of the piston, and whose outer edge is fixed to the main body. Balanced discharge valve for railway vehicles.