Patent Application
20230001910
The disclosure relates to a fluid valve. The disclosure also relates to a pneumatic valve arrangement and a pneumatic braking system for a vehicle, in particular for a trailer vehicle.
Here, fluid valves are understood to be valves for all flowing media, in particular pneumatic valves, preferably for use in pneumatic braking systems. Pneumatic braking systems in trailer vehicles with park release valves can perform various safety functions. For example, what is referred to as a park/save function can be provided, which is intended to avoid a dangerous situation in conjunction with incorrect operation. When a trailer vehicle is being coupled to a tractor vehicle, the park release valve should be in the parking position. However, even if the park release valve is in its driving position, the as yet uncoupled trailer vehicle is braked since existing spring-loaded brakes are then vented and active. If, in this situation with the park release valve in the driving position, the supply pressure line of the trailer vehicle is now first of all connected to the tractor vehicle by mistake, the spring-loaded brakes are supplied with air and released if the braking system of the trailer vehicle does not have a park/save function. The trailer vehicle can move, even though this is not desired at this time and there is a risk for operators. The park/save function, in contrast, has the effect that the spring-loaded brakes are not yet supplied with air and released under these conditions. On the contrary, the service brake must be actuated at least once. The brake pressure introduced in this case acts as a control pressure for canceling the park/save function. The park/save function and a possible design solution are illustrated in DE 10 2016 005 625 A1, in particular in conjunction with
The park/save function can be integrated into a “park release” valve or can be a component of a valve arrangement via which a park release function is realized. In this regard, FIG. 7 of DE 10 2016 005 625 A1 shows a pneumatic circuit diagram, and
A simpler construction of the individual components is possible by lower integration. The park release valve can be configured as a simple slide valve, while the park/save function can be implemented by a valve provided specifically for this purpose.
It is an object of the present disclosure to provide a fluid valve which is suitable as a parking safety valve or for implementing the park/save function. In particular, the fluid valve should be as reliable, smooth-running and maintenance-free as possible.
The object can, for example, be achieved via a fluid valve having a pressure inlet and a pressure outlet. The fluid valve is provided with a lip seal having a sealing lip between the pressure inlet and the pressure outlet, wherein a position of the sealing lip can be varied to vary a passage cross section. According to the disclosure, the sealing lip can assume different positions, thus enabling a passage cross section between the pressure inlet and the pressure outlet to be set. It is preferable if the sealing lip is not moved as a whole. On the contrary, only part of the sealing lip is angled or bent relative to the lip seal. To achieve this, the sealing lip can be produced from a correspondingly elastic material, as can the lip seal as a whole.
The fluid valve is provided, in particular, for pneumatic braking systems in trailer vehicles but can also be used for other applications in connection with flowing media. In contrast to conventional slide valves or seat valves, the frictional forces in the illustrated fluid valve with a switchable lip seal are relatively low.
According to a further concept of the disclosure, provision is made for the sealing lip to rest against a sealing surface in a blocking position and to be at a distance from the sealing surface in a passage position. The passage cross section is defined by the distance and the given geometric conditions.
According to a further concept of the disclosure, provision can be made for the sealing lip to have an internal stress which acts on the sealing lip to reduce the passage cross section. This means that, without being influenced by other components, the sealing lip tends to assume the position with the smallest passage cross section. In particular, the sealing lip then rests against a sealing surface. It is advantageous if the sealing lip extends at an acute angle to the sealing surface and is arranged in a self-retaining manner, that is, when there is a higher pressure at the pressure inlet than at the pressure outlet, the sealing lip is pressed against the sealing surface by the pressure difference and thus holds the abovementioned blocking position.
According to a further concept of the disclosure, provision can be made for the position of the sealing lip to be variable by pressure of a switching element. Via the switching element, the passage cross section is varied indirectly. Here, the pressure of the switching element preferably acts against the internal stress of the sealing lip. The switching element is used to vary the position of the sealing lip and can itself be controlled, for example, by a fluid.
By moving the switching element, it is possible to exert the pressure of the switching element and to switch the sealing lip, thus making it possible optionally to open and close the connection from the pressure inlet to the pressure outlet, or merely to vary the passage cross section. By varying the passage cross section, the sealing lip can thus be switched in a continuously variable manner. Actuation of the sealing lip by the switching element can take place directly or indirectly. For example, an additional component can be provided between the switching element and the sealing lip. The switching element then acts only indirectly on the sealing lip.
According to a further concept of the disclosure, provision can be made for the sealing lip to be supported on the switching element in a blocking position. In the blocking position, the sealing lip then rests, on the one hand, against the sealing surface and, on the other hand, is supported by the switching element, preferably by an edge or collar of the switching element.
According to a further concept of the disclosure, the switching element can rest against the sealing lip, wherein the sealing lip can be acted upon by the switching element to enlarge the passage cross section. In particular, the switching element acts on the sealing lip to a greater extent in a passage position than in the blocking position.
According to a further concept of the disclosure, the lip seal can have a lip holder, on which the sealing lip is held. An angle of the sealing lip relative to the lip holder can be variable by mechanical pressure of the switching element. The change in the angle can also be obtained by deformation of the sealing lip.
According to a further concept of the disclosure, the switching element can be of mushroom-shaped configuration with a stem and a cap. The lip holder can be of cup-shaped configuration with a cup opening and a bottom, wherein the bottom has a bottom opening. The stem can extend into the cup opening as far as the bottom opening. The cap can then rest against the lip seal in the passage position. The lip seal or the cap can be provided with a sealing bead. In this way, the cap seals the cup opening in the passage position of the lip seal.
According to a further concept of the disclosure, the cap can have a circumferential collar which is inclined toward the bottom of the lip holder, wherein the sealing lip extends circumferentially outward from an edge adjacent to the cup opening, and wherein the sealing lip is acted upon by the collar of the cap in the passage position. The collar preferably acts on the sealing lip during the entire actuation of the sealing lip, in particular also in the blocking position.
According to a further concept of the disclosure, the switching element can be acted upon by a return spring in the direction of relief of the sealing lip. The return spring acts against the switching element and must be additionally overcome by pressure at the control port or pressure outlet, as must the internal stress of the sealing lip.
The fluid valve can have a housing.
According to a further concept of the disclosure, provision can be made for the switching element to be movable in the housing counter to the action of the return spring, and for a widened portion of the switching element to rest against a shoulder of the housing with a minimized passage cross section as a result of the action of the return spring. The return spring, the widened portion and the shoulder define an end position of the switching element movable in the housing of the fluid valve.
According to a further concept of the disclosure, the lip holder can be arranged in a fixed manner in the housing. Like the sealing lip, the lip holder is then part of the lip seal. The lip holder is provided in a fixed manner, while the sealing lip is movable or flexible. When the passage cross section is varied, the sealing lip changes its shape, its position and/or its angle relative to the lip holder.
According to a further concept of the disclosure, the housing can have a cylindrical interior space. The switching element can be movable in the axial direction in the interior space. In addition, the lip seal can be held in the interior space. The switching element and the lip seal are preferably matched to the cylindrical shape of the interior space.
According to a further concept of the disclosure, when the passage cross section is closed, the sealing lip can divide the interior space into an outlet volume, which is connected to the pressure outlet, and an inlet volume, which is connected to the pressure inlet. When the passage cross section is not closed, the outlet volume and the inlet volume are connected to one another via the passage cross section.
According to a further concept of the disclosure, a relief volume connected to a relief outlet can be formed between the lip seal and the switching element, wherein the relief volume and the outlet volume are connected to one another via a flow channel in the switching element, at least in a blocking position of the sealing lip. As a result, in the blocking position, a defined pressure is present in the outlet volume, namely as in the relief volume, which is connected to the relief outlet. The pressure at the relief outlet typically corresponds to an ambient pressure of the fluid valve.
According to a further concept of the disclosure, a connection from the relief volume to the flow channel can be closed by a seal between the lip seal and the switching element in the passage position of the sealing lip. The seal separates the relief volume from the flow channel and the outlet volume connected thereto. In this way, the flow channel is securely closed in the passage position.
According to a further concept of the disclosure, a control piston, which can be moved between an initial position and an actuating position, can be present in a housing of the fluid valve, can be moved out of its initial position by pressure at a control port and, in the actuating position, acts on a switching element to actuate the sealing lip. With the movement of the control piston into the actuating position, the sealing lip moves into the passage position. According to a further concept of the disclosure, the control piston can separate a control volume, which is connected to the control port, from an outlet volume, which is connected to the pressure outlet. For this purpose, the control piston is preferably provided with a circumferential seal. The control piston can be moved to reduce the outlet volume by rising pressure in the control volume.
According to a further concept of the disclosure, at least two switching positions can be provided, namely the blocking position and the passage position. Furthermore, at least four ports can be provided, namely the pressure inlet, the pressure outlet, a relief outlet and a control port. Furthermore, a switching element can be movable in the housing. The movable switching element can be provided for the purpose of selectively opening or closing the passage cross section from the pressure inlet to the pressure outlet depending on the pressure at the pressure outlet and at the control port. The switching element can have a holding function, the holding function being configured such that the passage cross section is open when the pressure at the control port is above a first limit value, and remains open even when the pressure at the control port falls below the first limit value again but, at the same time, there is a pressure above a second limit value at the pressure outlet. As a result of the holding function provided, special functions can be performed with the fluid valve, for example as a parking safety valve in a pneumatic braking system. The limit values mentioned are preferably between 1 and 3.5 bar, in particular between 2 and 3 bar. The first and second limit values may be identical, but may also differ.
A pneumatic valve arrangement having a park release valve can have a fluid valve as described herein. In this case, the fluid valve preferably has the function of a parking safety valve. The valve arrangement is preferably provided for a braking system of a vehicle, in particular for a braking system of a trailer vehicle.
According to a further concept of the disclosure, the pressure inlet of the fluid valve can be connected to a supply port, which is at supply pressure, of the valve arrangement, wherein the pressure outlet of the fluid valve is connected to a port of the park release valve, and a control port of the fluid valve is connected to a control port of the valve arrangement. The control port of the valve arrangement can preferably be acted upon by brake pressure from the pneumatic braking system. In a trailer vehicle, the supply port of the valve arrangement receives the supply pressure from a “supply” coupling head, while the brake pressure is fed in via a “brake” coupling head.
The disclosure also relates to a pneumatic braking system for a trailer vehicle, having a fluid valve as disclosed herein or having a valve arrangement as disclosed herein.
The invention will now be described with reference to the drawings wherein:
A fluid valve F illustrated in
In order to clarify and distinguish between further reference numerals, the abovementioned numerals in the figures are in each case provided with a circle.
Details of the fluid valve F are explained with reference to the alignment illustrated in the figures. Direction indications used here, such as “top”, “bottom”, “side”, or terms including direction indications relate to the illustration in the figures. It is possible to rotate the fluid valve F relative to this arrangement. The direction indications must then be adapted accordingly.
The fluid valve F has a cylindrical housing 125 with an upper wall 126, a bottom wall 127 and a circumferential side wall 128. The control port 4F is provided in the region of the upper wall 126. A control piston 122 is axially movable in the housing 125 below the upper wall 126 and is provided with a circumferential seal 128a.
A lip seal 129 is arranged on the bottom wall 127 and has a cup-shaped lip holder 129a with a cup opening 148 and with a bottom-side, radially directed bottom collar 130. A collar-like sealing lip 132 extends outward from an upper edge 131 of the cup-shaped lip holder 129a. The sealing lip 132 is directed obliquely downward and, in the first switching position/blocking position shown in
The housing 125 has the pressure inlet 1-1F at the side and the pressure outlet 2F axially above it. The sealing surface 134 is located between the pressure inlet 1-1F and the pressure outlet 2F.
The bottom collar 130 is additionally provided radially on the outside with a sealing bead 135, which rests on the inside against the side wall 128 and/or against the bottom wall 127. A circumferential sealing bead 136 is provided on the upper edge 131.
Arranged between the control piston 122 and the lip seal 129 there is a switching element 123, here of T-shaped configuration, which has a cap 137 with a stem 138 underneath it. The stem 138 extends from above into the cup opening 148 and through a bottom opening 139 of the lip holder 129a. At the same time, the stem 138 extends through a bottom-side opening 140 of the housing 125. In this case, the stem 138 is held by a lower widened portion 141 in the opening 140, which has a shoulder 142. The bottom opening 139 and the opening 140 of the housing 125 are arranged coaxially.
A return spring 121 is seated on the stem 138, presses the cap 137 with the stem 138 upward and is supported in the cup-shaped lip holder 129a, with the result that the widened portion 141 rests against the shoulder 142 from below, see the first switching position/blocking position in
The cap 137 of the switching element 123 is provided radially on the outside with a downwardly directed collar 143, the lower edge 144 of which supports the sealing lip 132 on the outside or rests against it without pressure. In
An interior space 146 of the housing 125 is at least divided into an inlet volume Ve connected to the pressure inlet 1-1F, an outlet volume Va connected to the pressure outlet 2F, a relief volume V3 connected, in particular, via the bottom opening 139 and the opening 140 to the relief outlet 3F, and a control volume VS connected to the control port 4F.
The lower sealing edge 133 has come away from the sealing surface 134 and a passage 147 has been created from the pressure inlet 1-1F to the pressure outlet 2F, resulting in a pressure equalization. At the same time, the cap 137 comes into contact with the sealing bead 136. A pressure equalization within a trapped volume Vg formed thereby between the sealing bead 136, the collar 143 and the sealing lip 132 radially outside the sealing bead 136 is possible through the flow channels 145.
Starting from the second switching position in
In summary, the following states are shown in
The first limit value for the pressure at the control port 4F and the second limit value for the pressure in the outlet volume Va are preferably between 1 and 3.5 bar, in particular between 2 and 3 bar. The force of the return spring 121 and the two limit values mentioned are matched to one another.
In contrast to
Likewise as a departure from the illustration in the figures, the fluid valve F need not necessarily have the control piston 122 and the control port 4F. Instead, there may also be some other type of control or actuation of the switching element 123, such as electromagnetic actuation as in the case of a solenoid valve or a mechanical pushbutton. The important elements are lip seal 129, switching element 123, pressure inlet 1-1F, pressure outlet 2F, relief outlet 3F and preferably the return spring 121 or some other return element and any type of actuation of the switching element 123.
The fluid valve F can be used for all applications in connection with flowing media. In contrast to conventional slide valves or seat valves, the frictional forces in the illustrated fluid valve with a switchable lip seal are relatively low.
The illustrated fluid valve can be used, for example, in a pneumatic braking system for a trailer vehicle of the kind illustrated, for example, in DE 10 2016 005 625 A1,
Without this being intended to result in a restriction of the disclosure, a fluid valve according to the disclosure is illustrated by way of example in
As for the illustration of the fluid valve F, the following also applies below: Direction indications used here for clarification, such as “top”, “bottom”, “side”, or terms including direction indications, such as “bottom opening”, “bottom collar”, et cetera, relate to the illustration in the figures. It is possible to install the parking safety valve 216, 216a in a position rotated relative to this. The direction indications must then be adapted accordingly.
A valve arrangement 210 has a park release valve 211 in the form of a 5/3-way valve with operating unit 212 and ports P1, P2, P3, P4, P5. Moreover, the park release valve 211 is provided with a control port PS, via which a control piston 214 arranged in a control volume 213 can be acted upon in order to adjust the park release valve 211.
A further component of the valve arrangement 210 is an emergency brake valve 215 with ports N1, N2, N3 and control port NS, in the form of a 3/2-way valve.
A further component of the valve arrangement 210 is a parking safety valve 216 with ports 1-1S, 2S, 3S and control inlet 4Sa and 4Sb, in the form of a 3/2-way valve.
A further component of the valve arrangement 210 is an adjustable check valve 217 with ports VR1, VR2 and a control port VRS.
Finally, another component of the valve arrangement 210 is a simple check valve 218 with ports ER1 and ER2.
The valve arrangement 210 is integrated into the pneumatic braking system of a trailer vehicle (not shown specifically) in a manner similar to that illustrated in DE 10 2016 005 625 A1. In pneumatic circuit diagrams, inlets and outlets of pneumatic elements are usually provided with standardized designations. This is also the case in the figures. The corresponding ports of the valve arrangement 210 are
and are each provided with a circle for clarity.
In addition, in the figures, the ports of the parking safety valve 216 are also numbered in accordance with the standardized designations, namely
For clarity, these port designations are also each provided with a circle.
The connection of the valves 211, 215, 216, 217 and 218 to the ports can be seen in
Port 1-1S is connected as a pressure inlet to the supply port 1-1. Port 2S, as a pressure outlet, is connected via a node 219 to control port 4Sb, on the one hand, and to port P1 of the park release valve 211, on the other hand. In the illustrated driving position of the park release valve 211, there is a connection from port P1 to port P4 and from there to the control port NS of the emergency brake valve 215.
Control port 4Sa is connected via a node 220 to the control port 4 of the valve arrangement 210 and to port N1 of the emergency brake valve 215. In the driving position shown in
The parking safety valve 216 in
In the driving position shown, the parking safety valve 216 is used to supply port P1 of the park release valve 211 with supply pressure via the supply port 1-1 only when, after a pressure loss, for example due to the uncoupling of a trailer vehicle from the tractor vehicle, brake pressure has been fed in at least once via control port 4.
In the first switching position according to
When there is sufficient pressure at control port 4Sa, the control piston 222 switches a switching element 223 into the passage position according to
An embodiment of the parking safety valve 216a is illustrated in axial section in
In a cylindrical housing 225 with an upper wall 226, a bottom wall 227 and a circumferential side wall 228, the control piston 222 can be moved axially in an upper region below control port 4Sa and is provided with a circumferential seal 228a.
A lip seal 229 is arranged on the bottom wall 227 and has a cup-shaped lip holder 229a with a cup opening 248 and a bottom-side, radially directed bottom collar 230. A collar-like sealing lip 232 extends outward from an upper edge 231 of the lip holder 229a. The sealing lip 232 is directed obliquely downward and, in the blocking position shown in
The bottom collar 230 is additionally provided radially on the outside with a sealing bead 235, which rests on the inside against the side wall 228 and/or against the bottom wall 227. A circumferential sealing bead 236 is provided on the upper edge 231.
The housing 225 has the pressure inlet 1-1S at the side and the pressure outlet 2S. The sealing surface 234 is located between the pressure inlet 1-1S and the pressure outlet 2S.
Arranged between the control piston 222 and the lip seal 229 there is the switching element 223, here of T-shaped configuration, which has a cap 237 with a stem 238 underneath it. The stem 238 extends from above into the cup opening 248 and through a bottom opening 239 of the lip holder 229a and a bottom-side opening 240 of the housing 225 and is held by a lower widened portion 241 in the opening 240, which has a shoulder 242.
The return spring 221 is seated on the stem 238, presses the cap 237 with the stem 238 upward and is supported in the cup-shaped lip holder 229a, with the result that the widened portion 241 rests against the shoulder 242, see the blocking position in
The cap 237 is provided radially on the outside with a downwardly directed collar 243, the lower edge 244 of which supports the sealing lip 232 on the outside or rests against it without pressure. The sealing bead 236 is at a distance from the cap 237. Flow channels 245 are located in the cap 237, thus enabling air to be admitted to a space between the sealing bead 236 and the collar 243.
An interior space 246 of the housing 225 is at least divided into an inlet volume Ve connected to the pressure inlet 1-1S, an outlet volume Va connected to the pressure outlet 2S, a relief volume V3 connected via the bottom opening 239 and the opening 240 to the relief outlet 3S, and a control volume VS connected to control port 4Sa. The relief outlet 3S has, in particular, the function of a vent.
Starting from the switching position in
In summary, the following states are shown in
The pressure at control port 4Sa in
The parking safety valve 216, 216a explained via the embodiments, which is provided, in particular, for pneumatic braking systems in trailer vehicles, can also be used—as described—for other applications in connection with flowing media. In contrast to conventional slide valves or seat valves, the frictional forces in the illustrated parking safety valve with a switchable lip seal are relatively low.
It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 106 212.5 | Mar 2020 | DE | national |
This application is a continuation application of international patent application PCT/EP2021/055562, filed Mar. 5, 2021 designating the United States and claiming priority from German application 10 2020 106 212.5, filed Mar. 6, 2020, and the entire content of both applications is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2021/055562 | Mar 2021 | US |
| Child | 17898135 | US |
