Pneumatic Brake for a Rail Vehicle

Abstract

A pneumatic brake for a rail vehicle, wherein friction linings are pressed against friction partners during a braking process via pneumatic pressure from a brake air container that is fed from a compressed air supply, where the filling and the outflow of compressed air from the brake air container occurs via a flow limiting device.

Claims

1.-5. (canceled)

6. A pneumatic brake for a rail vehicle, comprising: a compressed air supply; a brake air reservoir fed from the compressed air supply; and a flow limiting device; wherein during a braking operation friction linings are pressed onto friction partners via pneumatic pressure from the brake air reservoir; wherein the filling and outflow of compressed air from the brake air reservoir occurs via the flow limiting device.

7. The pneumatic brake for a rail vehicle as claimed in claim 6, wherein the flow limiting device consists of a parallel connection of a non-return valve and a restrictor.

8. The pneumatic brake for a rail vehicle as claimed in claim 6, wherein the flow limiting device comprises an overflow valve.

9. The pneumatic brake for a rail vehicle as claimed in claim 7, wherein the flow limiting device is formed as a restrictor non-return valve with a non-return valve and a restrictor in one common housing.

10. A rail vehicle, comprising the pneumatic brake as claimed in claim 6.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention along with embodiments and advantages are explained by way of example in the following using the drawings, in which:

[0015] FIG. 1 is a schematic illustration of a brake system with a flow limiting device in accordance with the invention; and

[0016] FIG. 2 is a schematic illustration of the brake system of FIG. 1 with a flow limiting device formed as an overflow valve.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0017] FIG. 1 shows by way of example and schematically a brake system with a flow limiting device. The pneumatic circuit diagram of part of a compressed air system of a rail vehicle with a pneumatic brake 1 is illustrated. A compressed air supply 3 is fitted with a main air reservoir 11, which serves to supply compressed air, such that even when the requirement for compressed air is briefly high, the pressure in the pneumatic system does not drop sharply. The compressed air system comprises a plurality of further components, such as compressors, pressure regulators, measuring devices and consumer loads such as door drives, or folding step drives. To simplify the illustration, these are not shown in FIG. 1.

[0018] The pneumatic brake system 1 is supplied with compressed air from the general compressed air system, where a brake non-return valve 4 prevents the return flow of compressed air from the pneumatic brake system 1 into the general compressed air system. Thus, the pressure in the pneumatic brake system 1 is maintained even if the general compressed air system is out of operation, e.g., because of a defect in one of its components, and the pressure in it drops or disappears completely. The pneumatic brake system 1 comprises a brake valve 5 that can be actuated by the train crew or the vehicle control system and which in this case conducts a pneumatic pressure proportional to the desired braking rate to the brake actuators 6. The brake actuators 6 each comprise a pneumatic cylinder, the force action of which is used to press brake linings onto brake disks. In the exemplary illustrated embodiment, two brake actuators 6 are represented in the embodiment as disk brakes. However, the number and embodiment of the brake actuators 6 is unimportant. The pneumatic brake 1 is furthermore fitted with a brake air reservoir 2 that has a supply of air available exclusively for braking operations and that is also filled from the compressed air supply 3 via the brake non-return valve 4. In conventional brake systems, in the event of a defect (loss of pressure maintenance) in this brake air reservoir 2 the pneumatic pressure in the pneumatic brake 1 would, as a function of the cross-section of the opening through which compressed air escapes and the volume flow continuing to flow out of the compressed air supply 3, drop so sharply that in some cases no further braking would be possible In accordance with the disclosed embodiments of the invention, a restrictor non-return valve 7 is therefore arranged in the supply line to the brake air reservoir 2, and comprises a parallel connection of a restrictor 8 and a non-return valve 9. In the event of a loss of pressure maintenance of the brake air reservoir 2, the pneumatic brake 1 thus vents into the open air via the restrictor 8, where because of the outflow opening restricted by the nozzle 8 the pressure drop in the pneumatic brake 1 is sharply reduced and in any case still permits braking so long as the compressed air supply 3 is in operation. The non-return valve 9 connected in parallel to the nozzle 8 permits a rapid removal of compressed air, uninfluenced by the nozzle 8, from the brake air reservoir 2 in normal operation. The brake air reservoir 2 is filled from the compressed air supply 3 at a somewhat reduced rate because of the nozzle 8. In specific embodiments, pressure measurement devices are also provided at the pneumatic brake 1, via which a pressure drop can be identified; these are not illustrated in FIG. 1.

[0019] FIG. 2 shows by way of example and schematically a brake system with a flow limiting device formed as an overflow valve. The pneumatic circuit diagram of part of a compressed air system of a rail vehicle with a pneumatic brake 1 as in FIG. 1 is illustrated. Except for the flow limiting device, all the components are identical. In the exemplary illustrated embodiment, this flow limiting device is constructed as an overflow valve 10 that, in the event of a loss of pressure maintenance of the brake air reservoir 2, prevents an unrestricted outflow of compressed air, which thus ensures that the air pressure in the pneumatic brake 1 remains sufficient for braking operations.

[0020] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.