DD149923A5 - FAST BRAKE ACCELERATOR - Google Patents

Abstract

1. A rapid-braking accelerator for a railway vehicle indirect-acting compressed air brake with a control piston (12) which is subjected on one side thereof to the pressure in the main air line (10) of the brake and on the other side thereof to the pressure in a control chamber (17), which communicates with the main air line (10) through a choke (16), with an accelerator valve (13, 14) which vents the main air line (10) when a predetermined excess pressure is present in the control chamber (17) effecting the control piston (12) to open the accelerator valve (13, 14), and with a valve which is controlled by a pressure acting against the force of a pretensioned spring (30) arranged in a space (35) open to the atmosphere, wherein the spring (30) is pretensioned to a force corresponding to a pressure exceeding the maximum service control pressure in the main air line (10) by a determined value, characterised by a closable by-pass channel (34) arranged in parallel to said choke (16) and a by-pass valve (31, 32) closing the by-pass channel (34), the by-pass valve (31, 32) being opened by the pressure of a high filling shock (D1, D2) against the force of the pretensioned spring (30).

Description

Schnellbremsbeschleuni_qer application of the invention

The invention relates to a Schnellbremsbeschleuniger for indirectly acting air brakes of rail vehicles, with a control piston, on the one hand in the closing direction of an accelerator controlled by him, which causes in the open position the venting of the main air line, the pressure of the main air line and on the other hand from the pressure of, with the main air line via a Throttle point connected control chamber is acted upon. Characteristic of the known technical solutions It is known that on long passenger and freight trains the prescribed short Bremszylinderfüllzeit on single cars with the service brake accelerators can not be complied with, as emptied when performing quick braking the main air line against the train too slowly. With the help of additional quick brake accelerators of the type described above, the main air line is connected to the atmosphere via a large cross section during rapid braking on each car, so that the main air line empties quickly at the end of the train. However, these Schnellbremsbeschleuniger must be so insensitive and work so smoothly that an accidental start-up is excluded when performing any service braking. This is achieved by an appropriate dimensioning of the main air line and the control chamber connecting throttle point.

Object of the invention

Recently, however, are used in the international city express trains compressed air braking devices, which brake release long-lasting filling bursts up to 8 bar. einsteuern in the main air line, which in particular have a steep Abklingcharakteristik. This sharp drop in pressure on the decay of the Füllstosses can now

2g previously used Schnellbremsbeschleuniger to uner-. wish to bring in response.

In a known Schnellbremsbeschleuniger (DE-OS 27 29 848) is to eliminate the mentioned disadvantages in the connection of the main air line to the control chamber, a shut-off valve before the throttle point classified. This valve shuts off the connection between the main air line and the control cam at a certain filling pressure above the operating pressure, whereby the instantaneous pressure in the control cam is kept constant during a filling impact. The disadvantage here is the delayed by the pressure equalization phase at the end of a Füllstosses responsiveness of the Schnellbremsbeschleunigers.

Explanation of the essence of the invention

15 'The invention solves the problem of providing a rapid braking accelerator, which does not respond undesirable even when decaying high Füllstössen and still has a timely instantaneous fast braking readiness.

The inventive quick brake accelerator is characterized in that a bypass valve is arranged parallel to the throttle point, which is controlled in the opening direction of one of the two pressures against the force of a spring. Advantageously, it is additionally prevented by a pressure retention device that the pressure of the main air line drops below a certain value.

The advantages achieved by the invention are essentially to be seen in the fact that at high fill levels of the control chamber pressure in time without delay. the main air line pressure is adjusted via the open bypass connection.

".

5. 3e 1980

56 970 26

In Giner further refinement, the Schnellbremsbeschleuniger characterized by the fact that the spring is biased to a pressure corresponding to the control pressure of the main air line pressure corresponding force According to a further feature, the bypass valve is designed as a biased check valve. A further embodiment provides that the bypass valve is controlled by a, standing under one of the two pressures against the force of a spring piston. Furthermore, there is a feature in that in a Bntlüftungskanal d the main air line, a pressure retention valve is arranged.

Finally, the quick-brake accelerator is characterized by a bypass valve. additionally controlling piston, which is loaded in the closing direction of the bypass valve of one of the two pressures against the force of a preloaded spring and a vent channel for the main air line, which opens unthrottled into the atmosphere.

-B-

embodiments

The inventive quick brake accelerator will be described below with reference to embodiments and drawings. 1, 4 and 5 'each show a schematically illustrated one

Quick braking accelerator on average; Fig. 2, 3, 6 and 7 each have a schematically illustrated

Cutout of a quick brake accelerator;

Fig. 8 is a diagram of the course of the two

Press Dl and D2 when releasing with a high level of impulse and a quick stop interrupting the impulse.

According to FIG. 1, a housing 1 contains a space 10 directly connected to the main air line, hereinafter referred to as main air line 10. Connected to this via a channel 101, a pressure chamber 11 is arranged on one side of a control piston 12. On the other side of the control piston 12 is a control chamber 17 which is connected via a channel 161 and a throttle point 16 with the main air line 10. A plunger 122 attached to the control piston 12 is intended to lift a valve disk 13 from a valve seat 14 against a closing spring 133, hereinafter referred to as an acceleration valve 13, 14. In the pressureless state, the control piston 12 is held by a spring 123 in the valve end position. A diaphragm 121 seals the two pressure chambers 11 and 17 from each other. A pressure retention valve 20 _r 21, consisting of'a valve plate 20, a valve seat 21 and a biased spring 23, holds a vent passage 15 closed to a predetermined pressure. The openings 24 form the venting points to the atmosphere.

Parallel to the throttle 16 is a lockable Bypa.sskanal 34 as an additional connection between the

-n-

Main air line 10 and the control chamber 17 is arranged. The conclusion is made by a bypass valve with a plate 31 and a valve seat · 32, and a closing spring 33. The bypass valve 31, 32 is controlled by a housing fixedly supported piston 40 with a piston rod 42 and a sealing membrane 41. Housing support supported in an atmospheric pressure having acting space 35 and acting against the piston 40, a prestressed spring 30 is arranged. , ,

The mode of action of the quick-brake accelerator is the following:

The position shown in FIG. 1 corresponds to the release state of the braking device. A pressure Dl in the main air line 10, also called operating control pressure, or in the pressure chamber 11 is equal to an equal pressure D2 in the control chamber 17 against. Thus, the acceleration valve 13, 14 remains closed. The spring 30 and the piston 40 are matched to one another such that, for example, a pressure acting on the piston 40 exceeding the maximum operating control pressure Dl of 5.0 bar by 0.2 bar is able to overcome the force of the prestressed spring 30. The bypass valve 31, 32 thus remains closed at operating control pressure.

At pressures Dl in the main air duct 10 to the maximum operating control pressure, e.g. 5.0 bar, the Schnellbremsbeschleuniger operates in a known manner in the release state, service braking, full braking or Schnellbrem-3Q solution, as well as when solving a charge without overcharging. Thus, a description of these processes is unnecessary.

Loosening by overflow with overcharge: Is after a successful braking, in which the pressures Dl and D2 have dropped to 3.5 bar, for example

Dl main air line pressure through a high, the maximum

Increases operating pressure substantially surpassing Füllstoss, so initially forms a pressure difference between the pressures Dl and D2, due to the slower filling of the control chamber via the throttle point 16. The pressure Dl in the main air line rises steeply according to the curve A in Fig. 8, to For example, 8 bar, while the pressure D2 in the control chamber 17 according to the curve B initially has a smaller pressure gradient. If the pressure D2 in the control chamber 17 reaches, for example, the value 5.2 bar, the piston 40 overcomes the force of the spring 30 and opens the bypass valve 31, 32 with the plunger 42. Thus, the pressure D2 in the control chamber 17 immediately becomes the main air line pressure Dl adjusted. Of course, the accelerator valve 13, 14 remains closed during this phase. With a relatively rapid decay at the end of the filling impact, the open bypass valve 31, 32 prevents the formation of a pressure difference between the pressures in the control chamber 17 and in the pressure chamber 11 until reaching a slightly above the maximum operating control pressure switching value S of the bypass valve. When the switching value S of, for example, 5.2 bar in the control chamber 17, the piston 40 is pushed by the force of the spring 30 back down and the closing spring 33 closes the bypass valve 31, 32nd

The briefly forming small pressure difference in the chambers 11 and 17 is below the prescribed threshold value of the acceleration valve 13, 14 and is eliminated via the throttle point 16 again. This embodiment of the invention thus prevents unwanted response .'des Schnellbremsbeschleunigers when decaying a filling impact. Also, the operational readiness for an emergency braking after removal of the filling impact is created without delay. If, as shown in FIG. 8, the filling impact is interrupted by rapid braking, then the two pressures D1 and D2 behave in accordance with the two curves E and F, respectively. The bend in the curve F is achieved by closing the bypass valve 31, 32.

220 021

acts. As a result, the pressure difference between the main air line 10 and the control chamber 17 necessary for rapid braking can now form.

In the case of rapid braking or full braking, the main air line pressure D 1 is not necessarily lowered below, for example, 3 bar. Advantageously, therefore, a pressure retention valve 20, 21 is classified in the vent channel 15. This pressure retention function exerts, for example, a prestressed check valve 20, 21, whose spring 27 supported on the housing and the effective pressure surface of the valve disk 20 are matched to one another in accordance with the desired closing value.

15 'According to FIG. 2, the bypass valve 31, 32 is formed as a check valve loaded by the control pressure D2 against the prestressed spring 30. The valve disk is fastened on a sleeve 36 displaceable in the space 35. Otherwise agrees with the training of Schnellbremsbeschleunigers.

that according to FIG. 1 match. The mode of action is analogous to that described for FIG.

In Fig. 3, whose not shown part of the Schnellbremsbeschleunigers also corresponds to that of Fig. 1, the pressure Dl of the main air line 10 acts against the force of the spring 30. Again, the bypass valve, as in Fig. 2, as a biased check valve 31, 32 formed. In the mode of operation is no longer the pressure D2 of the control chamber 17, but the pressure Dl the main air line 10 against the force of the spring 30 is used as opening pressure. The difference in the operation over the description of Fig. 1 is mainly that at a high, the operating control pressure significantly exceeding Füllstoss the bypass valve 31, 32 opens earlier / see Fig. £, curve C and thereby the pressure equalization of the two pressures Dl and D2 done earlier. The closing of the bypass valve 31, 32 at the decay of a filling impact remains virtually unchanged.

As a further advantageous embodiment, instead of the pressure retention valve 20, 21 am.Ausgang the vent passage 15, a pressure retention control device on the bypass valve 31, 32 according to FIGS. 5, 6 and 7 integrated. In this case, at a control ram 44 an additional control

^ Curtains,

the piston 50 with diaphragm 51 arranged fixed to the housing is loaded in the closing direction of the bypass valve 31, 32 by one of the two pressures D1 or D2 against the force of a pretensioned spring 52. The spring 52 is fixed to the housing in the atmospheric pressure on v / ironing space 35 and tuned with the pressure surface of the piston 50 such that, for example, a pressure of 3.0 bar, the force of the spring 52 overcomes and thus pushes the plunger 44 in the closing direction down , The vent channel 15 is open to the atmosphere.

The operation of the combined bypass pressure retention valve is as follows:

The position of the valves shown in Fig. 5 represents the dissolved operating state. In the unpressurized state, however, the bypass valve 31, 32 is opened due to the force of the prestressed spring 52. When filling the main air line 10, the control chamber 17 via the open bypass valve 31, 32 and via the connecting channels 34 and 161 filled directly. At a pressure of, for example, 3.0 bar, the bypass valve 31, 32 closes due to the force acting on the piston 50 against the force of the spring 52 pressure. The filling of the control chamber 17 is now carried out, as is known, via the throttle point

16. -

By triggering a rapid braking, the pressure difference between the two pressures Dl and D2 is so large that the piston 12. Via the plunger 122, the accelerator valve '13, 14 opens, whereby the air accelerates in the main air line 10 via the vent passage 15. can escape into the atmosphere. Likewise

 δ

but also the pressure D2 is reduced in the connecting chamber 34 via the throttle point 16. At a predetermined pressure thus overcomes the force of the spring 52 acting on the piston 50 pressure and opens the bypass valve 31, 3-2. Now, the control chamber 17 is vented accelerated and thereby in turn caused a pressure equalization between the two pressures Dl and D2. This has the consequence that the piston 12 is pressed down, whereby the accelerator valve 13, 14 closes, or prevents the venting of the main air line 10 into the atmosphere. Thus, a desired minimum pressure in the main air line 10 is maintained. It is clear that to maintain a desired minimum pressure, the cross sections of the lines, as well as the valves and αεί 5 ren controls must be dimensioned accordingly. In the case of overcharge of the rapid-braking accelerator by a high filling impact, the piston 4 0 counteracts the force of the spring 30 and with appropriate consideration of the pressure-retaining device 50, 52 via the control rod 44 to the bypass valve 31 and 32 in the aforementioned manner.

In FIGS. 6 and 7, instead of the pressure D2 of the control chamber 17, the pressure D1 of the main air line 10 acts on the piston 50 via the connecting line 102 and the pressure chamber 103. In addition, in FIG. 7, the pressure D1 of the main air line is indicated by the dashed line 104 introduced into a chamber 105. In contrast to the description of FIG. 5, instead of the pressure D2 of the control chamber 17, the pressure D1 of the main air line 10 acts accordingly. Otherwise the functions are the same.

Other examples are conceivable / e.g. Instead of the pressure Dl of the main air line 10, the pressure D2 of the control chamber 17 could act on the piston 50 according to FIG.

FIG. 4 differs from FIG. 3 only in that here the main air line pressure D 1 acts on the piston 40 counter to the force of the spring 30 via a channel 106 in a pressure chamber 107.

Claims (6)

1. Schnellbrerasbeschleuniger for indirectly acting air brakes of rail vehicles, with a control piston, on the one hand in the closing direction of an accelerator controlled by him, which causes in the open position the venting of the main air line, the pressure of the main air line and the other hand, the pressure of, with the main air line via a throttle point, connected by a connected control chamber, characterized in that parallel to the throttle point (16), a bypass valve (31; 32) is arranged in the Ö'ffnungs'richtung of one of the two pressures (D1, D2) against the force of a spring (30 ) is controlled. · 2. rapid braking accelerator according to item 1, characterized in that the spring (30) is biased to e ine a control pressure (D1) of the main air line (10) exceeding the pressure corresponding force. 3. rapid braking accelerator according to item 2, characterized in that the bypass valve (31 »32) is designed as a prestressed check valve. 4. rapid braking accelerator according to item 2, characterized in that the bypass valve (31, 32) is controlled by a piston (40) which is under one of the two pressures (D1, D2) against the force of the spring (30). 5. rapid braking accelerator according to one of the preceding points, characterized in that in a ventilation channel (15) of the main air line (10), a pressure-retaining valve (20; 21; 23) is arranged. -12- 56 970 26 5. 3. 1980 - 11 - "56 970 26 invention claim 6 «Rapid braking accelerator after one of the points 1 to 4j characterized by a bypass valve additionally controlling the piston (50) in the closing direction of the bypass valve of one of the two pressures
(DI, D2) counteracting force of a preloaded spring
(52) is loaded and a vent channel (15) for the main air line (10), which opens unthrottled into the atmosphere. For this 3 sheets of drawings