JPS6223333Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an air brake system for railway vehicles using a three-pressure control valve.

As is well known, pressure control valves used in air brake devices (hereinafter simply referred to as brake devices) of railway vehicles (hereinafter simply referred to as vehicles) include two-pressure control valves and three-pressure control valves.

The former two-pressure type control valve has an auxiliary air reservoir and an additional air reservoir that are filled with brake pipe pressure (5 kg/cm ² ) when the brake is released, and during service braking, the amount of pressure reduction in the brake pipe pressure is increased. The brake force is controlled by supplying pressurized air from the auxiliary air reservoir to the brake cylinder accordingly, but even if the brake pipe pressure is reduced beyond a predetermined amount (excessive pressure reduction), the brake cylinder pressure will be the same as the capacity of the auxiliary air reservoir and the brake force. The maximum value is regulated by the piston displacement capacity of the cylinder. This pressure value is called the service total brake pressure and is normally established to be 3.6 kg/cm ² . During emergency braking, the brake pipe pressure is reduced more rapidly and in a larger amount than during service braking, and the brake cylinder is supplied with pressurized air from the auxiliary air reservoir as well as the auxiliary air reservoir. The three pressures in the air reservoir and brake cylinder are balanced. The pressure value at this time is usually 4.5Kg/
It is established to be cm ² .

On the other hand, the latter three-pressure control valve, which will be described in detail later, is equipped with a supply air reservoir and a constant pressure air reservoir that maintains a constant pressure (5 kg/cm ² ) at all times. The brake force is controlled by supplying pressurized air from the supply air reservoir to the brake cylinder in proportion to the amount of pressure reduction, but the control valve always maintains constant pressure air when the sum of the force exerted by the brake pipe pressure and the force exerted by the brake cylinder is constant. Since it has the function of being equal to the force exerted by the reservoir pressure, if the brake pipe pressure is excessively reduced, the brake cylinder pressure will increase accordingly. During emergency braking, the brake pipe pressure is reduced more rapidly and in a larger amount than during service braking, so that the brake cylinder is supplied with high-pressure air at a rapid rate. At this time, the brake pipe pressure is close to atmospheric pressure, so
Brake cylinder pressure can rise to supply reservoir pressure. For this reason, conventional methods have been used to limit the maximum brake cylinder pressure by providing an emergency pressure limiting valve. However, the excessive pressure in the brake cylinder due to excessive depressurization of the brake pipe during service braking has not been limited.

For this purpose, a vehicle equipped with a three-pressure control valve,
When vehicles equipped with two-pressure control valves are operated in a mixed configuration, if the brake pipe pressure is excessively reduced due to the driver's carelessness during service brake operation, the above-mentioned vehicles with three-pressure control valves and two-pressure control valves Because the brake cylinder pressures of the attached vehicles are different, there is an imbalance in the braking force between the two vehicles, resulting in a shock between the vehicles, which adversely affects ride comfort and cargo, and causes derailment.

Therefore, this idea allows for even if a vehicle with a three-pressure control valve is combined with a vehicle with a two-pressure control valve,
In other words, in the pneumatic brake system for railway vehicles using the above-mentioned three-pressure type control valve, it is necessary to prevent shocks from occurring due to brake force imbalance between both vehicles, even if the brake pipe pressure is excessively reduced during service brake operation. The purpose is to prevent the brake cylinder pressure from exceeding the service full brake pressure.

The basic structure of this invention to achieve this purpose is to use a first supply air reservoir and a second supply air reservoir in place of the conventional supply air reservoir in an air brake system equipped with a three-pressure control valve. , the first supply air reservoir is always communicated with the three-pressure type control valve, and the capacity of the first supply air reservoir corresponds to the capacity at which the brake cylinder outputs the full normal brake pressure, that is, the auxiliary air reservoir of the two-pressure type control valve. capacity, and the second supply air reservoir is connected to a three-pressure type control valve via a switching valve, and when the brake pipe pressure is reduced to a predetermined pressure close to atmospheric pressure, the switching valve switches to supply the second supply air. The reservoir is configured to communicate with the three-pressure type control valve and the first supply air reservoir, and the capacity of the second supply air reservoir is set to a capacity at which the brake cylinder outputs the maximum brake pressure when the switching valve switches, that is, two pressures. This is a configuration in which the capacity is set to be greater than the capacity equivalent to the additional air reservoir of the type control valve.

In this invention, by having the above configuration, even if the brake pipe pressure is slightly excessively reduced during service brake operation, the switching valve will not switch, and the supply air reservoir communicating with the three-pressure type control valve will be connected to the small-capacity first air reservoir.
Since there is only a supply air reservoir, the brake cylinder pressure will not exceed the service full brake pressure. Therefore, when a vehicle equipped with the air brake system of this invention is combined with a vehicle equipped with a two-pressure control valve, no shock will occur between the two vehicles, providing a comfortable ride and preventing the load from collapsing. and derailment can be prevented.

As described above, this invention is a pneumatic brake system that uses a three-pressure control valve, and even if the brake pipe pressure is slightly excessively reduced during service brake operation, the brake cylinder pressure does not exceed the service full brake pressure, so the driver can This has the effect of eliminating the need to worry about excessive reduction in brake pipe pressure.

An embodiment of this invention will be described below based on the drawings.

First, an outline of a brake device using a three-pressure control valve will be explained based on FIG.

A brake system using a three-pressure control valve includes a three-pressure control valve 2 connected to a brake pipe 1, a brake cylinder 3, and an emergency pressure limiter connected between the three-pressure control valve 2 and the brake cylinder 3. The main component is the valve 4.

The three-pressure control valve 2 has an output chamber a connected to an emergency pressure limiting valve 4, a pressure chamber b connected to the brake pipe 1, and a pressure chamber b separated from the pressure chamber b by a control piston 5 having a membrane plate, and having a constant pressure. a pressure chamber c connected to the air reservoir 6 and to the brake pipe 1 via a check valve 7; a supply chamber c connected to the brake pipe 1 via a check valve 8 and also connected to the supply air reservoir 9; It has a chamber d, and an exhaust chamber e, which is separated from the output chamber a by a balancing piston 10 having a membrane plate and has an exhaust hole 11. supply room d
is formed on the upper side of a partition wall 13 in which an air supply hole 12 opening into the output chamber a is bored. A hollow tubular exhaust valve cylinder 15 having an opening 14 at its upper end is mounted on the balancing piston 10 in an upright state with an opening 16 at its lower end facing the exhaust chamber e. A valve rod 17 is attached to the lower end of this exhaust valve cylinder 15,
This valve rod 17 is a partition wall 18 between the exhaust chamber e and the pressure chamber b.
The lower end of the control piston 5 is fixed to the control piston 5 . Note that a spring 1 is provided in the output chamber a for biasing the balancing piston 10 from above.
9 is interposed. In addition, pressure chamber a and supply chamber d
An air supply valve seat 20 is provided around the air supply hole 12 provided in the partition wall 13 between the two, and an air supply valve urged downward by a spring 21 is provided in the supply chamber d above the air supply valve seat 20. 22 is stored.

The emergency pressure limiting valve 4 includes an input chamber f connected to the output chamber a of the three-pressure control valve 2, an output chamber g connected to the brake cylinder 3, and a balancing piston 23 having a membrane plate to control the output chamber. The spring chamber h is divided into a lower spring chamber h and a lower spring chamber h. A check valve seat 26 is provided around a ventilation hole 25 provided in a partition wall 24 between an input chamber f and an output chamber g, and a spring 27 pushes the check valve seat 26 downwardly into the input chamber f above the check valve seat 26. An energized check valve 28 is interposed. Further, the lower end of a valve rod 29 whose upper end faces into the ventilation hole 25 is fixed to the balancing piston 23 . The spring chamber h is open to the atmosphere, and when the pressure in the output chamber g is less than the maximum brake pressure (for example, 4.5 kg/cm ² ), the spring chamber h urges the balancing piston 23 upwards to open the valve. A spring 30 is interposed which separates the check valve 28 from the check valve seat 26 via the rod 29.

The pressure in the brake pipe 1 can be increased or decreased by operating a handle 32 of a brake valve 31 provided in the cab of the train. Further, such pressure increase/decrease in the brake pipe is similarly performed in a brake device using a two-pressure type control valve.

According to a brake system using a three-pressure control valve having such a configuration, first, when the brake is released as shown in FIG. , the brake pipe 1 has a maximum control pressure (for example, 5 kg/
cm ² ), the pressure chambers b, c and supply chamber d of the three-pressure control valve 2 connected to the brake pipe 1 have the same pressure, and therefore the control piston 5
is at rest in the relaxed position. For this reason, the output chamber a
communicates with the exhaust chamber e via the exhaust valve cylinder 15, so the pressure inside the chamber becomes atmospheric pressure. Also, this output chamber a
Since the input chamber f of the emergency pressure limiting valve 4, which is connected to the
The check valve 2 is urged upward by the valve stem 29.
8 to form a gap with the check valve seat 26. Therefore, since the output chamber g communicates with the input chamber f through the ventilation hole 25, the output chamber g and the output chamber g
The brake cylinder 3 connected to the brake cylinder 3 also has atmospheric pressure, and the brake is released.

Next, in order to apply the service brake, when the handle 32 of the brake valve 31 is operated to the service brake position to reduce the pressure in the brake pipe 1, a pressure difference is generated between the pressure chambers b and c, and the valve stem 17 and the exhaust valve Cylinder 15
is lifted, the air supply valve 22 is separated from the air supply valve seat 20, and the air supply chamber d and the output chamber a are connected through the air supply hole 12.
are in communication with each other, the pressurized air in the supply air reservoir 9 is supplied to the brake cylinder 3 through the input chamber f and output chamber g of the emergency pressure limiting valve 4, thereby applying the service brake. The output chamber g of the balancing piston 23 of the emergency pressure limiting valve 4 has a maximum brake pressure (for example, 4.5 kg/
cm ² ), the ventilation hole 25 remains open because it does not descend due to the biasing force of the spring 30. When the brake pipe pressure is reduced by a predetermined amount and then maintained, the output chamber a of the three-pressure control valve 2
is isolated from the supply chamber d and exhaust chamber e to maintain its pressure. Therefore, the pressure in the brake cylinder 3 corresponds to the amount of pressure reduction in the brake pipe 1.

When applying the emergency brake, operate the handle 32 of the brake valve 31 to the emergency brake position to rapidly reduce the pressure in the brake pipe 1. As the pressure difference between the pressure chambers b and c increases, the pressure is removed from the supply air reservoir 9. A large amount of pressurized air is supplied, the pressure in the brake cylinder 3 becomes high, and the emergency brake is activated. However, due to the emergency pressure limiting valve 4, a predetermined pressure (for example,
The pressure is limited not to increase above 4.5Kg/cm ² ).

Next, an embodiment of the brake device of this invention will be described based on FIGS. 2 to 4, but parts common to the above description will be omitted.

In the brake system of this invention, the supply air reservoir 9 of the brake system using the three-pressure type control valve is replaced by a first supply air reservoir having a capacity corresponding to the capacity of the auxiliary air reservoir of the brake system using the two-pressure type control valve. The first supply air reservoir 33 is divided into an air reservoir 33 and a second supply air reservoir 34 having a capacity greater than the capacity of the additional air reservoir of the device, and the first supply air reservoir 33 is directly connected to the supply chamber d of the three-pressure control valve 2. , when the brake pipe 1 is depressurized to a predetermined pressure close to atmospheric pressure, the second supply air reservoir 3
4 is connected to the supply chamber d of the three-pressure control valve 2.

The switching valve 35 includes an input chamber i connected to the second supply air reservoir 34, an output chamber j connected to the supply chamber d of the three-pressure control valve 2, and a switching valve 35 located below the output chamber j. and a spring chamber l open to the atmosphere, which is separated from the pressure chamber k by a control piston 36 having a membrane plate. A check valve seat 39 is provided around the ventilation hole 38 provided in the partition wall 37 between the input chamber i and the output chamber j, and the input chamber i above the check valve seat 39 is provided with a downward direction by a spring 40. A check valve 41 that is biased toward the inside is interposed. Further, a valve rod 43 that slidably and airtightly penetrates the partition wall 42 between the output chamber j and the pressure chamber k has its lower end fixed to the control piston 36 and its upper end facing the vent hole 38. .
The spring chamber 1 accommodates a spring 44 that urges the control piston 36 upward when the pressure in the pressure chamber k is below a predetermined pressure (for example, 1 kg/cm ² ) close to atmospheric pressure.

Next, the operation of the embodiment having the above configuration will be explained.

In the brake released state shown in FIG. 2, by releasing the handle 32 of the brake valve 31,
The maximum control pressure in brake pipe 1 (for example, 5 kg/
cm ² ), the operation of the brake system using the three-pressure control valve connected to the brake pipe 1 is the same as described above. On the other hand, the air pressure (for example, 5 kg/cm ² ) enters the pressure chamber k of the switching valve 35 connected to the brake pipe 1, but the biasing force of the spring 44 is greater than the force exerted by this air pressure on the control piston 36. Because of its small size, the control piston 36 remains in the down position, and the check valve 41 is seated on the check valve seat 39 by the biasing force of the spring 40. At this time, the first supply air reservoir 33 and the second supply air reservoir 34 are also filled with pressurized air, similar to the brake pipe 1.

When the handle 32 of the brake valve 31 is operated to the service brake position to reduce the pressure in the brake pipe 1, the state shown in FIG. 3 is achieved. In this case, the control piston 5 rises due to the pressure difference between the two pressure chambers b and c of the three-pressure control valve 2, lifts the air supply valve 22 by the exhaust valve cylinder 15, and lifts it from the air intake valve seat 20. Since the seats are separated from each other, the pressurized air in the first supply air reservoir 33 that is being supplied to the air supply chamber d is transferred from the air supply hole 12 to the output chamber a,
It is led to the brake cylinder 3 via the input chamber f and output chamber g of the emergency pressure limiting valve 4. The pressure in the output chamber a of the three-pressure control valve 2 increases, and the balance piston 1
The sum of the force acting on the effective area of 0 and the pressure in the pressure chamber b (brake pipe pressure) and the force acting on the control piston 5 and the spring 19 is the pressure in the pressure chamber c below the control piston 5 (constant pressure air The balance piston 10 and the control piston 5 move downward, and the upper end opening 14 of the exhaust valve cylinder 15 contacts the air supply valve 22, and the air supply valve 22 closes the air supply valve 22. It is seated on the air valve seat 20, shutting off the supply chamber d and the output chamber a, and maintaining the pressure in the output chamber a. In the switching valve 35, the pressure in the pressure chamber k is reduced together with the pressure in the brake pipe 1, but the control piston 36 presses the spring 44, and the valve stem 43 separates from the check valve 41.
is seated on the check valve seat 39. Therefore, the second supply air reservoir 34 is isolated from the supply chamber d of the three-pressure control valve 2 by the check valve 41.

Now, if brake pipe 1 is excessively depressurized,
The pressure chamber b of the three-pressure control valve 2 is depressurized, and the control piston 5 moves upward due to the pressure difference between the upper and lower sides.
The exhaust valve cylinder 15 pushes up the air supply valve 22 and separates it from the air supply valve seat 20, thereby communicating the output chamber a with the first supply air reservoir. At this time, in the switching valve 35, the spring 44 does not displace the check valve 41 from the check valve seat 39 via the valve stem 43 until the pressure in the pressure chamber k becomes close to atmospheric pressure. Therefore, the check valve 41 is seated on the check valve seat 39, and the output chamber j is isolated from the input chamber i, that is, the second supply air reservoir 34. Therefore, if the air supply valve 22 of the three-pressure control valve 2 continues to be open, only the pressurized air in the first supply air reservoir 33 will flow into the brake cylinder 3 as described above, and eventually the pressures of both will be reduced. A state of equilibrium is reached. The relationship between the first supply air reservoir 33 and the brake cylinder 3 in this case is the relationship between the auxiliary air reservoir and the brake cylinder in a two-pressure control valve system, and the capacity of the first supply air reservoir with respect to the capacity of the brake cylinder is the auxiliary air reservoir and the brake cylinder. By setting it to correspond to the capacity of the reservoir, it is possible to obtain the same brake cylinder pressure as a brake device with a two-pressure control valve.

Next, when the handle 32 of the brake valve 31 is operated to the emergency brake position and the brake pipe 1 pressure is suddenly reduced, the state shown in FIG. 4 is reached. In this case, since the pressure chamber k of the switching valve 35 is also rapidly depressurized, the control piston 36 is moved upward by the biasing force of the spring 44. Then, the valve stem 43 lifts the check valve 41 against the biasing force of the spring 40 and displaces it from the check valve seat 39, thereby opening the vent hole 38.
As a result, the pressurized air in the second supply air reservoir 34 passes through the input chamber i and the output chamber j of the switching valve 35, merges with the pressure air in the first supply air reservoir 33, and flows into the supply chamber of the three-pressure control valve 2. be guided by d. The air supply valve 22 of this control valve 2 has an air supply valve seat 2 for the same reason as described above.
0, the pressurized air guided to the supply chamber d is guided to the brake cylinder 3 via the output chamber a, the input chamber f of the emergency pressure control valve 4, and the output chamber g, and then the emergency brake is applied. to act.

In this case, the relationship between the second supply air reservoir 34 and the brake cylinder 3 is that of the additional air reservoir and the brake cylinder in a two-pressure control valve system, and the capacity of the second supply air reservoir 34 is equal to the capacity of the brake cylinder 3. By setting the capacity to correspond to the capacity of the additional air reservoir, it is possible to obtain the same brake cylinder pressure as a brake system with a two-pressure control valve even during emergency braking.

However, if the brake system is not equipped with a gap adjuster to keep the gap between the brake shoe and the wheel tread constant, which fluctuates due to wear of the brake shoe, etc., The brake cylinder piston stroke gradually increases with wear, and as a result, the piston displacement capacity of the brake cylinder 3 increases. When the emergency brake is applied in such a state, the brake cylinder pressure decreases in proportion to the increase in displacement of the brake cylinder piston, and the emergency braking force decreases. In order to prevent this, in this embodiment, the capacity of the second supply air reservoir 34 is set larger than the capacity of the corresponding additional air reservoir of the two-pressure control valve equipped brake system. This will be explained below.

When the piston stroke of the brake cylinder 3 is a predetermined value, the capacity of the second supply air reservoir 34 is larger than the capacity of the corresponding additional air reservoir of the brake device with a three-pressure control valve, so the final The pressure at which the pressure air in the first supply air reservoir 33, the second supply air reservoir 34, and the brake cylinder 3 are balanced is higher than that of a two-pressure control valve system equipped with an additional air reservoir, but the brake cylinder An emergency pressure control valve 4 installed in the pipe line 3 acts to limit the pressure of the brake cylinder 3 to a predetermined emergency brake pressure, thereby obtaining a predetermined emergency braking force. Even if the piston displacement capacity of the brake cylinder 3 increases due to wear of the brake shoe, the final equilibrium pressure of the first supply air reservoir 33, the second supply air reservoir 34, and the brake cylinder 3 during emergency braking will remain at the predetermined pressure ( 4.5Kg/
cm ² ), but as mentioned above, the pressure in the brake cylinder 3 is limited to the maximum brake pressure (4.5 kg/cm ² ) by the action of the emergency pressure limiting valve 4. That is, it is possible to prevent a decrease in brake cylinder pressure due to an excessive brake cylinder stroke, thereby preventing a decrease in braking force during emergency braking.

As is clear from the above explanation, the brake system of this invention maintains the brake cylinder pressure at full normal braking even if the brake pipe pressure is slightly excessively reduced during normal braking due to the actions of the first and second supply air reservoirs and the switching valve. This service total brake pressure is the same as the service total brake pressure of a brake system using a two-pressure control valve. Therefore, if a vehicle equipped with a brake system using the three-pressure type control valve of this invention is mixed with a vehicle equipped with a brake system using a two-pressure type control valve, the driver may accidentally over-tighten the brake pipe during service braking. Even if the pressure is reduced, the same braking force is applied to both vehicles, and no large impact is generated between the couplers as in the conventional case. As a result, smooth driving is possible, without causing uncomfortable riding or damage to the cargo, and the driver does not have to worry about excessive depressurization of the brake pipe, eliminating stress during driving. be able to.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a brake device using a conventional three-pressure control valve, and Figs. 2 to 4 are schematic diagrams of the brake device of this invention. Figure 3 shows the state when the service brake is applied, and Figure 4 shows the state when the emergency brake is applied. 1... Brake pipe, 2... Three-pressure control valve, 3
... Brake cylinder, 4 ... Emergency pressure limiting valve,
6... Constant pressure air reservoir, 9... Supply air reservoir, 33...
First supply air reservoir, 34...Second supply air reservoir, 35
...Switching valve.

Claims (1)

[Scope of utility model registration request] An emergency pressure limiting valve that limits the maximum brake pressure of the brake cylinder is connected to a three-pressure control valve that controls the air pressure supplied from the supply air reservoir to the brake cylinder according to the pressure difference between the constant pressure air reservoir and the brake pipe. In the air brake device for a railway vehicle, the supply air reservoir is composed of a first supply air reservoir and a second supply air reservoir, the first supply air reservoir is directly connected to the three-pressure type control valve, and the second supply air reservoir is directly connected to the three-pressure control valve. Connecting the air reservoir to the three-pressure control valve via a switching valve,
The switching valve is configured to switch when the brake pipe is depressurized to a predetermined pressure close to atmospheric pressure to communicate the second supply air reservoir with the three-pressure control valve and the first supply air reservoir, and The capacity of the air reservoir is set to a capacity at which the brake cylinder outputs the full normal brake pressure, and the capacity of the second supply air reservoir is set to a capacity at which the brake cylinder outputs the maximum brake pressure when the switching valve is switched. An air brake device for railway vehicles characterized by the following.