JPH0443022B2 - - Google Patents

Abstract

PURPOSE:To prevent leakage and to improve the controllability by penetrating the extended portion of discharge valve through a communication path between the balance chambers above/below of a piston and a brake tube chamber while forming a check valve with a valve formed on said extended portion and a valve seat formed in the piston. CONSTITUTION:The extended portion of a discharge valve 26 is penetrated through a communication path 33 between the balance chambers 23 above/below of a piston 22 and a brake tube chamber 24. The inserting section 30 at the tip of said extended portion is fitted into a hole forming the back pressure chamber 31 of the body 21. The effective area S2 of the back pressure chamber 31 is made approximately same with the effective area S1' of the valve seat 29 in the discharge valve 26 while the back pressure chamber 31 and the discharge chamber 25 are communicated through a communication path 32. A flange section 34 is formed on the extended portion of the discharge valve 26 while a valve 34a is arranged at the flange section 34. A valve seat 22a is formed in the piston 22 while a check valve for allowing flow only from the balance chamber 23 to the brake tube chamber 24 is formed with the valve 34a and the valve seat 22a. Consequently, leakage from the brake chamber 24 into the balance chamber 23 at the overlapping position of brake valve is prevented.

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]

An air brake system for a railway vehicle using a conventional balanced discharge valve A is shown in Figure 3. In the figure, 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 4 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 inter-brake 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 at the same time, 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 fourth
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 BV is set to the brake position c and the pressure in the balance air reservoir ER is reduced to the desired pressure, for example, P ₁ (as shown by t ₃ in Figure 5), let's maintain the pressure P ₁ in 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 P in the balance air reservoir _ER and the pressure P in the brake pipe BP are the same as the pressure P BP in the brake pipe _BP 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 e,
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 sliding chamber protruding toward the brake pipe chamber side of the piston. A balanced discharge valve comprising an exhaust valve that is movably fitted and biased by a spring to open and close between a brake pipe chamber and the exhaust chamber, wherein the balance chamber side of the exhaust valve is connected to the piston. A back pressure chamber is formed at the end of the inserted portion by being slidably inserted into the main body so as to protrude through the main body, and the back pressure chamber and the exhaust chamber are connected by a communication hole bored through the exhaust valve. The balance chamber and the brake pipe chamber are in communication with each other, and the effective area of the back pressure chamber is formed to be approximately the same as the effective area of the valve seat on which the exhaust valve is seated and removed, and the balance chamber and the brake pipe chamber are formed in a portion where the exhaust valve fits into the piston. a valve seat is formed on the side surface of the balancing chamber of the piston, and a flange portion is provided on the protruding portion of the exhaust valve toward the balancing chamber side, so that the valve seat of the piston is attached to the flange portion. The piston is configured to open and close the communication passage when the piston is unseated, and an airtight membrane plate is provided, the inner edge of which is fixed to the outer periphery of the piston, and the outer edge of which 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 the outer circumference of the piston is provided with a membrane plate, there is no leakage from the brake pipe chamber to the balance chamber through the outer circumference of the piston, and the valve seat of the piston, which also serves as a check valve, is seated on the flange. Since this check valve faces the balancing chamber in the opposite direction, there is no leakage from the brake pipe chamber to the balancing chamber through the communication path. Therefore, when the exhaust operation of this balanced discharge valve is completed and the exhaust valve is seated on the valve material, 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 2).

〔Example〕

An example is shown in FIG. In the figure, 20 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 has a valve seat 22 on the surface facing the balancing chamber 23.
a, and a balancing chamber 23 extending through the center.
A through hole 27 is formed to communicate between the brake pipe chamber 24 and the brake pipe chamber 24, and an exhaust valve 26 is slidably supported within the through hole 27. In the figure, a biasing spring 28 is provided between the piston 22 and the exhaust valve 26, and presses the exhaust valve 26 toward its valve seat 29.

The exhaust valve 26 is connected to the balance chamber 2 through the through hole 27.
A piston-shaped fitting portion 30 is formed so as to protrude toward the third side. A cylindrical back pressure chamber 31 is formed on the main body side corresponding to the fitting portion 30. This back pressure chamber 31 communicates with the exhaust chamber 25 through a communication hole 32 formed vertically through the center of the exhaust valve 26 . The effective area S ₂ of this back pressure chamber 31 is the exhaust valve 2
It is determined to be approximately equal to the effective area _S1 of the valve seat 29 of No.6.

Also, the through hole 27 of the piston 22 of the exhaust valve 26
A vertical groove is provided on the outer circumferential surface corresponding to the vertical groove, and this vertical groove forms a communication path 33 between the balancing chamber 23 and the brake interchamber 24. The piston 2
The communication path 33 is opened and closed by the second valve seat 22a being seated and removed. The flange portion 34 has a rubber seat 34a on its lower surface for cushioning and improving sealing performance when the valve seat 22a is seated. That is, the piston 22 also serves as a check valve whose forward direction is from the balancing chamber 23 to the brake pipe chamber 24.

A membrane plate 35 is provided between the outer periphery of the piston 22 and the inner surface of the body cavity through which the piston 22 moves up and down to maintain airtightness. That is,
The membrane plate 35 is a disc-shaped member having an inner hole, and its inner edge is hermetically fitted into a groove on the outer periphery of the piston 22.
Its outer edge is airtightly clamped to the main body. 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.

Note that 36 in the figure is a return spring, which is used to ensure that the piston 22 is in the raised position when air is introduced for the first time and does not constantly discharge air, but since the piston 22 has its own weight, it is omitted. Good too.

The balanced discharge valve 20 is generally used in place of the balanced discharge valve A of the brake device shown in FIGS. 3 and 4. That is, the balancing chamber 23 is connected to the balancing air reservoir ER and port 3 of the brake valve BV, and the brake pipe chamber 24 is connected to the brake pipe port 3.
BP is connected to port 4 of brake valve BV, and exhaust chamber 25 is connected to port 5 of brake valve BV. Note that, unlike the connection states shown in Figures 3 and 4, the balance air reservoir ER, balance discharge valve 20, and brake pipe BP are connected in series, and the air supply to the brake pipe BP is reversed. There may also be a usage state in which the piston 22, which is a stop valve, is pushed down and the connection is performed from the communication path 33.

This balanced discharge valve 20 operates in substantially the same manner as the conventional balanced discharge valve A. However, as shown in FIG. 2, the brake valve BV is relaxed from the brake position a to the brake position c at time _t1 , and the pressure PER in the balance air chamber 23 and the balance air reservoir _ER is reduced to the pressure _P1 . At time _t3 when the desired pressure reduction amount △P ₁ is reached, if the brake valve BV is set to the overlap position b, the pressure in the balance air chamber 23 and the balance air reservoir _ER is lower than the pressure P in the brake pipe chamber 24.
Although the pressure P _BP of the brake pipe BP is larger, there is no leakage between the two chambers 23 and 24 due to the provision of the membrane plate 35, and the communication path 33 also ensures that the valve seat 22a of the piston 22 Rubber seat 34 of flange portion 34
It is closed by sitting on a. Therefore, when the exhaust valve 26 opened due to a pressure difference closes due to pressure equilibrium, the pressure P _BP in the brake pipe chamber 24 and the brake pipe BP is initially equal to that in the balancing air chamber 23.
and the pressure in the balance air reservoir _ER is extremely close to the pressure P ₁ corresponding to the desired pressure reduction amount △P ₁ obtained by reducing the pressure of ER, and since the differential pressure is always constant, the pressure P It can be considered as something. That is, the reason why the pressures P _ER and P _BP do not match is due to the weight of the piston 22 and the biasing action of the spring 36, and the differential pressure caused by this is due to the length of the brake pipe BP and the balance air reservoir ER This is because it is constant regardless of the amount of pressure reduction.

The piston 22, which is a check valve, opens away from the flange portion 34 when the air pressure on the balance chamber 23 side becomes higher than the air pressure on the brake pipe chamber 24 side.
This substantially corresponds to the leak groove 14 of the conventional balanced discharge valve A.

〔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 driving 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 level of skill is achieved.

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

As another means for solving the above-mentioned conventional problems, a balanced discharge valve 60 shown in FIG. 6 may be considered. This is a balanced discharge valve 60 having a slightly different configuration from the balanced discharge valve 20 of the present invention shown in FIG. 1, except for the fitting part 30 and the back pressure chamber 31. This alternative means that the pressure in the balance air reservoir _ER and the pressure in the brake pipe _BP are set to a predetermined pressure (usually 5 kg/cm ² ).
In the loosened state, the brake pipe BP
The exhaust valve 26 is pressed against the valve seat 40 by a pressure _PBP , and the force is ( _PBP × _S1 ). Therefore, during braking (ER depressurization), the force that raises the piston 22 due to the pressure difference between the brake pipe pressure P _BP and the equilibrium air reservoir pressure P _ER is (P _BP ×S ₁ ).
Brake pipe BP must be equal to or greater than
depressurization will not start. In other words, as shown in Fig. 7, the exhaust valve 26 opens and the brakes are activated when the pressure difference between the brake pipe pressure P _BP and the equilibrium air reservoir pressure P _ER exceeds △P. , the brake is activated from time t ₂ , which is delayed by a time Δt from time t ₁ when exhaustion of the balance air reservoir ER starts.

In contrast to this other means, the means of the present invention is provided with a fitting portion 30 and a back pressure chamber 31, thereby canceling out the force pressing the exhaust valve 26 against the valve seat 29, as shown in FIG. The effect is that there is no delay (brake activation delay) of the time Δt shown.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing a schematic configuration of an embodiment of the present invention, and Fig. 2 shows a state in which the embodiment of the present invention is used in place of a conventional brake device's counterbalanced discharge valve for regular braking operation. Graph showing changes in brake pipe pressure P _BP and balance air reservoir pressure P _ER over time; Figure 3 is a piping diagram showing the general configuration of a conventional brake system; Figure 4 is a diagram showing the conventional balance pressure A schematic diagram showing a vertical cross-sectional view of a discharge valve and a symbolized brake valve connected thereto, FIG. 5 is a graph corresponding to FIG. 2 of the conventional brake device, and FIG. 6 is a diagram different from the present invention. FIG. 7 is a longitudinal sectional view of a balanced discharge valve shown as a means for this, and is a graph corresponding to FIG. 2 when using another means. BV...Brake valve, ER...Balancing air reservoir, BP
... Brake pipe, CV ... Control valve, BC ... Brake cylinder, 20 ... Balance discharge valve, 21 ... Main body, 22 ... Piston check valve, 22a ... Valve seat,
23... Balance room, 24... Brake pipe room, 25...
...Exhaust chamber, 26...Exhaust valve, 29...Valve seat, 30
...Inset part, 31...Back pressure chamber, 32...Communication hole,
33... Connection path, 34... Flange section, 35...
Membrane plate.

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 brake pipe chamber; an exhaust valve that protrudes toward the brake pipe chamber side of the piston, is slidably fitted therein, and is 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, the balance chamber side of the exhaust valve projects through the piston and is slidably fitted into the main body, forming a back pressure chamber at the end of the fitting part. The back pressure chamber and the exhaust chamber are communicated through a communication hole bored through the exhaust valve, and the effective area of the back pressure chamber is approximately equal to the effective area of the valve seat on which the exhaust valve is seated and removed. A communication path for communicating the balance chamber and the brake pipe chamber is provided at the fitting part of the exhaust valve into the piston, and a valve seat is formed on the side surface of the balance chamber of the piston, and the exhaust valve A flange portion is provided on a protruding portion toward the balance chamber side of the piston, and the valve seat of the piston is configured to open and close the communication passage by seating and separating from the flange portion, and the inner edge thereof is fixed to the outer periphery of the piston. A balanced discharge valve for a railway vehicle, characterized in that it is provided with an airtight membrane plate whose outer edge is fixed to the main body.