Relay valve, valve device, and vehicle associated therewith

Abstract

A relay valve (2) includes a housing having a pressure medium inlet that can be connected to a pressure medium source, at least one pressure medium outlet that can be connected to a consumer, at least one control input, and at least one ventilation (32) leading to the atmosphere. The relay valve (2) has further a relay valve piston (14), which is arranged in the housing along a relay valve piston axis (16) in a slidable manner. The relay valve (2) has a first sealing element (54) fixed to the housing, and a second sealing element (56) fixed to the relay valve piston for sealing the relay valve piston (14) with respect to the housing. An annular space (58) having a connection to the atmosphere is defined by the first sealing element (54), the second sealing element (56), the relay valve piston (14), and the housing.

Claims

1. A relay valve for a compressed air system, comprising: a housing comprising a pressure medium input configured to be connected to a pressure medium source, at least one pressure medium output configured to be connected to a consumer, at least one control input, and at least one purge (32) leading to atmosphere, a relay valve piston (14) which is arranged in the housing displaceably along a relay valve piston axis (16), a first sealing element (54) for sealing the relay valve piston (14) against the housing, wherein the first sealing element (54) is fixed to the housing, a second sealing element (56) for sealing the relay valve piston (14) against the housing, wherein the second sealing element (56) is fixedly arranged on the relay valve piston (14), an annular chamber (58) which is delimited by the first sealing element (54), the second sealing element (56), the relay valve piston (14) and the housing, and a connection of the annular chamber (58) to the atmosphere, wherein a part of a control chamber (22) connected to the control input is separated off as a damping volume (68), the control chamber (22) and the damping volume (68) being connected together via a choke (72), wherein the damping volume (68) is separated from the control chamber (22) via a diaphragm (70), and an opening in the diaphragm acts as the choke (72).

2. The relay valve as claimed in claim 1, wherein the housing has a two-part configuration with a first housing part (4) and a second housing part (6), wherein the second housing part (6) is constructed as a flat cover which is sealingly connected to the first housing part (4).

3. The relay valve as claimed in claim 1, wherein the connection of the annular chamber (58) to atmosphere includes an axial bore (62) in the relay valve piston (14), the axial bore (62) leading into a purge chamber (30), and a channel (60) in the relay valve piston (14) which is configured to connect the axial bore (62) to the annular chamber (58).

4. The relay valve as claimed in claim 1, wherein the annular chamber (58) has a size adapted to establish a predefined ratio of a pressure present at the pressure medium output to a control pressure present at the control input.

5. The relay valve as claimed in claim 4, wherein the predefined ratio is a 1:1 ratio.

6. A relay valve for a compressed air system, comprising: a housing comprising a pressure medium input configured to be connected to a pressure medium source, at least one pressure medium output configured to be connected to a consumer, at least one control input, and at least one purge (32) leading to atmosphere, a relay valve piston (14) which is arranged in the housing displaceably along a relay valve piston axis (16), a first sealing element (54) for sealing the relay valve piston (14) against the housing, wherein the first sealing element (54) is fixed to the housing, a second sealing element (56) for sealing the relay valve piston (14) against the housing, wherein the second sealing element (56) is fixedly arranged on the relay valve piston (14), an annular chamber (58) which is delimited by the first sealing element (54), the second sealing element (56), the relay valve piston (14) and the housing, and a connection of the annular chamber (58) to the atmosphere, wherein a damping volume (76) is arranged in the relay valve piston (14), wherein the damping volume (76) and a control chamber (22) connected to the control input are connected together via a choke (78).

7. The relay valve as claimed in claim 6, wherein the housing has a two-part configuration with a first housing part (4) and a second housing part (6), wherein the second housing part (6) is constructed as a flat cover which is sealingly connected to the first housing part (4).

8. The relay valve as claimed in claim 6, wherein the connection of the annular chamber (58) to atmosphere includes an axial bore (62) in the relay valve piston (14), the axial bore (62) leading into a purge chamber (30), and a channel (60) in the relay valve piston (14) which is configured to connect the axial bore (62) to the annular chamber (58).

9. The relay valve as claimed in claim 6, wherein the annular chamber (58) has a size adapted to establish a predefined ratio of a pressure present at the pressure medium output to a control pressure present at the control input.

10. The relay valve as claimed in claim 9, wherein the predefined ratio is a 1:1 ratio.

11. A valve arrangement for a compressed air system, comprising two relay valves, one of which is the relay valve according to claim 1.

12. The valve arrangement as claimed in claim 11, wherein the two relay valves (2) are arranged in a valve block, wherein the two relay valves (2) are connected via a common purge chamber (30).

13. A vehicle comprising at least two relay valves, one of which is the relay valve according to claim 1.

14. A valve arrangement for a compressed air system, comprising two relay valves, one of which is the relay valve according to claim 6.

15. The valve arrangement as claimed in claim 14, wherein the two relay valves (2) are arranged in a valve block, wherein the two relay valves (2) are connected via a common purge chamber (30).

16. A vehicle comprising at least two relay valves, one of which is the relay valve according to claim 6.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, FIG. 1 shows a relay valve according to the prior art,

(2) FIG. 2 shows a relay valve according to one exemplary embodiment of the invention,

(3) FIG. 3 shows a relay valve according to a further exemplary embodiment of the invention with damping volume connected upstream,

(4) FIG. 4 shows a relay valve according to a further exemplary embodiment of the invention with damping volume connected downstream, and

(5) FIG. 5 shows a pneumatic circuit diagram of an EBS trailer modulator.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) FIG. 1 shows a relay valve 2 according to the prior art with a housing which is formed from a first housing part 4 and a second housing part 6. The two housing parts 4, 6 are fixedly connected together and sealed against each other by means of a sealing element 10.

(7) The second housing part 6 has a relay valve piston guide 12 protruding far towards the inside, in which a relay valve piston 14 is arranged displaceably along a relay valve piston axis 16. A sealing ring 18 seals the second housing part 6 against the displaceably arranged relay valve piston 14.

(8) On the edge sides of the second housing part 6 runs a sealing ring 20, formed as a Z-ring, which also serves to seal against the displaceably arranged relay valve piston 14.

(9) A control chamber 22 is arranged above the relay valve piston 14 and delimited by the relay valve piston 14 and the second housing part 6. A control pressure can be guided into the control chamber 22 via a control pressure line 24.

(10) The relay valve 2 is shown in a purge position in FIG. 1. For this, compressed air is conducted from a working chamber 26, past an insert 28, into a purge chamber 30 which is connected to atmosphere via an output 32, so that the compressed air to be purged can escape through the purge chamber 30.

(11) In this position, the pressure in the working chamber 26 exceeds the pressure in the control chamber 22, or the two pressures are in equilibrium.

(12) The working chamber 26 has a pressure medium output (not shown here), through which it can be pneumatically connected to a consumer, for example a brake cylinder.

(13) If the pressure in the working chamber 26 is at least as great as the control pressure in the control chamber 22, compressed air is purged from a consumer. However as soon the control pressure in the control chamber 22 is slightly higher than the pressure in the working chamber 26, the relay valve piston 14 assumes a neutral position. In the neutral position, a gap between the relay valve piston 14 and a filling piston 34 is closed, so that an outlet valve 36 pneumatically divides the working chamber 26 from the purge chamber 30.

(14) The filling piston 34 is preferably over-molded with a rubber and held in position by a spring 38.

(15) If the control pressure in the control chamber 22 is increased further, the relay valve piston 14 is moved into a filling position, wherein the control pressure relative to the working pressure is great enough to move both the relay valve piston 14 against its friction at the sealing rings 18 and 20 and the filling piston 34 against the spring force of the spring 38.

(16) In this position, a gap is created between the purge piston 34 and the insert 28 which pneumatically connects a filling chamber 40 to the working chamber 26, and thus an inlet valve 41 opens. The filling chamber 40 is supplied with compressed air from a compressed air source via a pressure medium input, not shown here.

(17) The filling piston 34 and the spring 38 are carried by a carrier element 42 which is inserted in the first housing part 4 and sealed by means of a sealing ring 44.

(18) An opening 46 ensures a pressure balance in the chamber containing the spring 38. A further sealing ring 48 pneumatically seals the first housing part 4 against the insert 28, or the filling chamber 40 against the working chamber 26.

(19) In order to keep the friction forces of the relay valve piston 14 on the second housing part 6, caused by the seals 18 and 20, as low as possible and to guarantee tightness, the second housing part 6 must disadvantageously be extensively machined to achieve a high surface quality.

(20) FIG. 2 shows an embodiment of a relay valve piston 2 according to the invention in whichaccording to the inventionthe second housing part 6 is configured as a flat cover which is tightly connected to the first housing part 4 by means of a sealing ring 52.

(21) A first sealing element 54, in particular a Z-ring, is arranged lying on a shoulder between the second housing part 6 and the first housing part 4, and seals the relay valve piston 14 from the first housing part 4. The sealing element 54 is mounted fixedly on the housing and, on movement of the relay valve piston 14, slides on this relay valve piston 14.

(22) A second sealing element 56 is arranged in a circumferential groove in the relay valve piston 14 and lies fixedly on the relay valve piston 14, sliding in the first housing part 4.

(23) The relay valve piston 14, the first housing part 4 and the two sealing elements 54 and 56 together delimit an annular chamber 58 which is connected to atmosphere via a channel 60 and an axial bore 62 in the relay valve piston 14.

(24) The relay valve 2 shown in FIG. 2 has a 1:1 ratio, where the annular chamber 58 is dimensioned such that, because of the diameter difference, its active face area is the same size as and opposed to the active face area formed by the purge seat 64.

(25) Such an embodiment of the invention advantageously ensures the desired equality of areas on the control side and output side, wherein only the first housing part 4 requires machining, since here only sealing elements 54 and 56 sliding between the housing part 4 and the relay valve piston 14 are provided. The second housing part 6, formed as a cover, can be produced particularly easily and economically, in particular from low-cost plastic.

(26) FIG. 3 shows a relay valve 2 according to a further exemplary embodiment of the invention, with a damping volume 68 connected upstream. To separate the control chamber 22 from the damping volume 68, a diaphragm 70 is inserted in the control chamber 22, wherein the diaphragm 70 has an opening 72 acting as a choke. The diaphragm 70 may be configured separately and glued or welded into the control chamber 22, or be taken into account in the construction of the second housing part 6 formed as a cover. The opening 72 in the diaphragm 70 should be dimensioned such that vibrations of the relay valve piston 14 are advantageously avoided.

(27) FIG. 4 shows a relay valve 2 according to a further exemplary embodiment of the invention, with a damping volume 76 arranged downstream. According to the invention, this damping volume 76 is arranged in the relay valve piston and connected to the control chamber 22 with a choke 78. When the damping volume 76 and the size of the choke 78 are correctly configured, here too, advantageously, the vibration behavior of the relay valve piston 14 can be suppressed.

(28) FIG. 5 shows a pneumatic circuit diagram to explain the use according to the invention of a damping volume 68, 76 arranged upstream or downstream, using the example of an EBS trailer modulator. For the sake of simplicity, here one damping volume 68 is shown connected upstream and one damping volume 76 connected downstream. Preferably however, a symmetrical construction of two upstream or two downstream damping volumes 68 or 76 is implemented. An asymmetric arrangement according to FIG. 5 is not however excluded.

(29) The EBS trailer modulator, shown in simplified form, first has a control electronics unit (ECU) 80 to which the components of the modulator are electrically connected.

(30) Furthermore, the modulator has a port 82, via which the modulator is supplied with accumulator pressure. In addition, as well as a plurality of components, a plurality of pressure sensors 84 is connected to the control electronics 80 and a redundancy valve 86 is provided.

(31) To supply two consumer outputs 88 and 90, two relay valves 2.1 and 2.2 according to the invention are provided, wherein a damping volume 76 is connected downstream of the first relay valve 2.1 and a damping volume 68 is connected upstream of the second relay valve 2.2.

(32) The first relay valve 2.1 is controlled via an inlet valve 92.1 and an outlet valve 94.1, wherein the valves 92.1 and 94.1 may be separately connected to the control electronics 80 in order to maintain pressure, or may have a common port to the control electronics 80, wherein then the pressure line can be filled and purged only by means of the valves 92.1 and 94.1.

(33) The relay valve 2.1 is controlled via a downstream damping volume 76 which is connected to the control chamber 22 of the relay valve 2.1 via a connecting choke 78.

(34) The second relay valve 2.2 is also controlled via an inlet valve 92.2 and an outlet valve 94.2 which are connected to the control electronics 80 in the same way as the valves 92.1 and 94.1.

(35) The control pressure provided by the outlet valve 94.2 passes into the relay valve 2.2 via an upstream damping volume 68 which is connected to the control chamber 22 of the relay valve 2.2 via a connecting choke 72.

(36) The use of two relay valves 2.1 and 2.2 in an EBS trailer module with two upstream or two downstream damping volumes 68 or 76 has the advantage of suppressing the disruptive vibration behavior of the relay valves 2.1 and 2.2. According to the invention, the volumes of the damping volumes 68, 76 and the size of the connecting chokes 72, 78 are dimensioned so as to achieve a friction-independent, inherent damping of the respective systems.

(37) All features cited in the description above and in the claims may be combined both individually and in arbitrary combination with the features of the independent claims. The disclosure of the invention is not therefore restricted to the feature combinations described or claimed. Rather, all feature combinations sensible within the context of the invention are considered disclosed.

(38) While the above description constitutes the preferred embodiments of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.