Seat valve with electromagnetic actuation

Abstract

A seat valve with electromagnetic actuation combines, in one device, the functions of a seat valve, of a pressure-limiting valve and optionally also of one or more check valves. Furthermore, the switching noise of the seat valve function is reduced. In a de-energized state of an electromagnet, a fluid flow from a port P to a port TNC occurs only if a pressure difference between the ports P and TNC exceeds a limit value of p.sub.G, wherein the force of the specified pressure difference overcomes the force of a spring and therefore pushes a first sealing body out of a first sealing seat, and in the energized state of the electromagnet, a fluid flow from port P to port TNC occurs even in the case of a pressure difference less than p.sub.G if the force of the electromagnet together with the force of the pressure difference between the ports P and TNC overcomes the force of the spring, wherein the sum of the specified forces pushes the first sealing body out of the first sealing seat. The seat valve may be used in hydraulic brake systems of vehicles, also in vehicle gear mechanisms or in hydraulic drives.

Claims

1. A seat valve actuated by an electromagnet has a valve sleeve with at least one first sealing seat, has at least one first sealing body connected in a force-fitting manner to an armature of the electromagnet, and has at least two ports, the at least two ports includes port (P) and port (TNC), for fluid flows, wherein, in a de-energized state of the electromagnet, a fluid flow from the port (P) to the port (TNC) occurs only if a pressure difference between the port (P) and the port (TNC) exceeds a limit value (p.sub.G), wherein the limit value (p.sub.G) is a first pressure force of the pressure difference between the port (P) and the port (TNC) that overcomes a spring force of a spring and pushes the first sealing body out of the first sealing seat, and in that in an energized state of the electromagnet, a fluid flow from the port (P) to the port (TNC) occurs even in the case of a pressure difference less than the limit valve (p.sub.G) if an electromagnet force of the electromagnet together with a pressure force of the pressure difference between the port (P) and the port (TNC) overcomes the spring force of the spring, wherein a sum of the electromagnetic force and the pressure force pushes the first sealing body out of the first sealing seat, and in that no fluid flow from the port (P) to the port (TNC) occurs if the spring force of the spring exceeds a sum of the pressure force of the pressure difference from the port (P) to the port (TNC) and of the electromagnetic force of the electromagnet, because then the first sealing body seals off in its first sealing seat.

2. The seat valve according to claim 1, wherein said seat valve has a further port (TNO) which, in a de-energized state of the electromagnet, is fluidically connected to the port (P) but, if a sum of all the forces on a second sealing body pushes said second sealing body into a second sealing seat, is not fluidically connected to the port (P), wherein the following forces have a closing action or an opening action on the sealing body: the electromagnetic force of the electromagnet, closing, the spring force of the spring, opening, a second pressure force of the pressure difference between the port (P) and the port (TNO), opening, the pressure force of the pressure difference between the port (P) and the port (TNC), closing.

3. The seat valve according to claim 2, wherein owing to an ability of an electrical controller, connected to the electromagnet, to generate different currents, the armature of the electromagnet is able to assume three working positions counter to the spring force of the spring, namely a rest position, when the electromagnet is energized with less current than a first current (I1), whereby, owing to the spring force of the spring, the connection of the port (P) and the port (TNO) is always open, and the connection of the port (P) and the port (TNC) is opened only by the first pressure force of the pressure difference between the port (P) and the port (TNC), if the specified pressure difference is greater than the limit value (p.sub.G), an intermediate position, when the electromagnet is energized with more current than the first current (I1) and less current than a second current (I2), in which the electromagnetic force of the electromagnet, the spring force of the spring, and of the pressure difference between the port (P) and the port (TNO) and between the port (P) and the port (TNC) are in equilibrium, wherein the port (P) is connected both to the port (TNO) and to the port (TNC) because the first sealing body and the second sealing body do not bear on their first sealing seat and second sealing seat, respectively, and an end position, when the electromagnet is energized with more current than (I2), wherein the port (P) is connected only to the port (TNC) but not to the port (TNO) because the second sealing body bears on the second sealing seat while the first sealing body is lifted off from the first sealing seat.

4. The seat valve according to claim 1, wherein a closure of the specified fluidic connections is in each case realized by a placement of the first or the second sealing body against the first or the second sealing seat, wherein the first and second sealing bodies are produced from a plastic which is selected from the group (PEEK, PEI, PESU and LCP).

5. The seat valve according to claim 1, wherein between the port (P) and the port (TNC), a first seal, which is produced from an elastomer material and which is designed as a lip seal, is arranged in an outer groove of the valve sleeve, and a lip of said first seal, when the sealing function of the latter is being applied, bears against an installation bore, wherein, if the pressure at the port (TNC) exceeds the pressure at the port (P), the first seal loses its sealing function and opens up a fluid flow from the port (TNC) to the port (P) because the lip lifts off from the installation bore.

6. The seat valve according to claim 2, wherein between the port (P) and the port (TNO), a second seal, which is produced from an elastomer material and which is designed as a lip seal, is arranged in a second outer groove on the valve sleeve, and a lip of said second seal, when the sealing function is being applied, bears against an installation bore, wherein, if the pressure at the port (TNO) exceeds the pressure at the port (P), the second seal loses its sealing function and opens up a fluid flow from the port (TNO) to the port (P) because the lip lifts off from the installation bore.

7. A seat valve comprising: an electromagnet having an armature configured to actuate the seat valve; a valve sleeve body having at least one first sealing seat and at least one first sealing body connected to the armature; a first port (P); and a second port (TNC); wherein when the electromagnet is de-energized, a fluid flow from the first port (P) to the second port (TNC) occurs if a pressure difference between the first port (P) and the second port (TNC) exceeds a limit value (p.sub.G), wherein the limit value (p.sub.G) is a limit value pressure difference force of the pressure difference between the port (P) and the port (TNC) that overcomes a spring force of a spring biasing the first sealing body out of the first sealing seat; wherein when the electromagnet is energized, a fluid flow from the first port (P) to the second port (TNC) occurs even if the pressure difference is less than the limit value (p.sub.G) if an electromagnetic force of the electromagnet together with a pressure difference force of the pressure difference between the first port (P) and the second port (TNC) overcomes the spring force of the spring, wherein a sum of the electromagnet force and the pressure difference force pushes the first sealing body out of the first sealing seat; and wherein no fluid flow occurs from the first port (P) to the second port (TNC) if the spring force of the spring exceeds a sum of the pressure difference force and the electromagnetic force because the first sealing body seals off the first sealing seat.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) Example embodiments will now be described more fully with reference to the accompanying drawings.

(2) The seat valve 1, as shown in FIG. 1, is actuated by an electromagnet 2, and has a valve sleeve 12 with at least one sealing seat 5, that has at least one first sealing body 4 connected in a force-fitting manner via a tappet 14 to an armature 10 of the electromagnet 2, and has at least two ports, namely the ports P and TNC, for fluid flows.

(3) In a de-energized state of the electromagnet 2, a fluid flow from P to TNC occurs only if the pressure difference between the ports P and TNC exceeds a limit value of p.sub.G.

(4) In this case, the force of the specified pressure difference overcomes the force of a spring 11 and therefore the first sealing body 4 is pushed out of a first sealing seat 5.

(5) In an energized state of the electromagnet 2, a fluid flow from P to TNC occurs even in the case of a pressure difference less than p.sub.G, because the force of the electromagnet 2 overcomes the force of the spring 11, wherein the first sealing body 4 is pushed out of the first sealing seat 5.

(6) Advantageously, the seat valve 1 has a further port TNO which, in the de-energized state of the electromagnet 2, is fluidically connected to the port P but, if the sum of all the forces on a second sealing body 6 pushes said body into a second sealing seat 7, is not fluidically connected to the port P. In this case, the following forces have a closing action or an opening action on the sealing body: the force of the electromagnet 2, closing, the force of the spring 11, opening, the force of the pressure difference between P and TNO, opening, the force of the pressure difference between P and TNC, closing.

(7) Furthermore advantageously, owing to the ability of an electrical controller, connected to the electromagnet, to generate different currents, the armature 10 of the electromagnet 2 is able to assume three working positions counter to the force of the spring 11, namely a rest position, when energization occurs with less current than I1, wherein the connection of the ports P and TNO is always open, and the connection of the ports P and TNC is opened only if the pressure difference between the ports P and TNC is greater than the limit value p.sub.G, an intermediate position, when energization occurs with more current than I1 and less current than I2, wherein the port P is connected both to the port TNO and to the port TNC because the two sealing bodies 4, 6 do not bear on their sealing seats 5, 7, an end position, when energization occurs with more current than I2, wherein the port P is connected only to the port TNC because the sealing body 6 bears on its sealing seat 7 and the sealing body 4 is lifted off from its sealing seat 5.

(8) Here, for example, the current I1 is 1.2 A and the current I2 is 1.5 A, and at 1.2 A, the force of the electromagnet 2 is sufficient to lift the sealing body 4 off from its sealing seat 5, but the force is not yet sufficient to push the spring 11 further in and to push the sealing body 6 into its sealing seat 7.

(9) Preferably, the closure of the specified fluidic connections is in each case realized by the placement of a first or a second sealing body 4, 6 against a first or a second sealing seat 5, 7, wherein the sealing bodies 4, 6 are produced from a plastic which is selected from the group (PEEK, PEI, PESU and LCP).

(10) The said materials are all suitable for this application, and they are selected according to their processability and the total costs.

(11) Advantageously, between the ports P and TNC, a first static seal 8, which is produced from an elastomer material and which is designed as a lip seal, is arranged in an outer groove of the valve sleeve 12. The lip of said seal bears against an installation bore 13 when the seal seals off. If the pressure at the port TNC exceeds the pressure at the port P, the seal 8 loses its sealing function because the pressure difference lifts the lip of the seal off from the installation bore, and a fluid flow from the port TNC to the port P is opened up.

(12) Likewise advantageously, also between the ports P and TNO, a second static seal 9, which is produced from an elastomer material and which is designed as a lip seal, is arranged in an outer groove of the valve sleeve 12. The lip of said seal bears against the installation bore 13 when the seal seals off. If the pressure at the port TNO exceeds the pressure at the port P, the seal 9 loses its sealing function because the pressure difference lifts the lip of the seal off from the installation bore, and a fluid flow from the port TNO to the port P is opened up.

LIST OF REFERENCE SIGNS

(13) 1. Seat valve 2. Electromagnet 4. First sealing body 5. First sealing seat 6. Second sealing body 7. Second sealing seat 8. Seal 9. Seal 10. Armature 11. Spring 12. Valve sleeve 13. Installation bore 14. Tappet P Port for fluid flow to the brake cylinder TNO Port for fluid flow to the consumer TNC Port for fluid flow to the pressure accumulator I1 Lower limit value for the electric current I2 Upper limit value for the electric current p.sub.G Limit value for the pressure difference

(14) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.