Control valve

Abstract

A control valve including: a valve housing including a piston space; and a control piston which is movably arranged in the piston space and sub-divides the piston space into at least a first valve space and a second valve space, the control valve including at least a leakage path which sets a desired leakage between the first valve space and the second valve space. A motor vehicle device including an adjustable rotary pump including an adjusting means, for adjusting a delivery volume of the rotary pump, and the control valve, using which a pressure for adjusting the adjusting means can be governed, the motor vehicle device including a means which presses the control piston into a first position and holds it there, and the at least one other inlet of the control valve is connected to a high-pressure side of the rotary pump when the rotary pump is in operation.

Claims

1. A control valve for an adjustable rotary pump of a motor vehicle, comprising: a valve housing which comprises a piston space; and a control piston which is movably arranged in the piston space and sub-divides the piston space into at least a first valve space and a second valve space, wherein at least one leakage path which sets a desired leakage between the first valve space and the second valve space is provided, and wherein the control piston sub divides the piston space into at least a third valve space, wherein another leakage between the third valve space and the second valve space and/or between the third valve space and the first valve space is smaller than the desired leakage.

2. The control valve according to claim 1, further comprising an inlet which feeds into the first valve space in at least a first position of the piston and/or an inlet which feeds into the third valve space in at least a second position of the piston, the second position of the piston may be the same or different than the first position.

3. The control valve according to claim 1, wherein in order to sub-divide the piston space, an inner wall of the valve housing and an outer wall of the control piston form a respective sealing gap which separates the valve spaces from each other.

4. The control valve according to claim 3, wherein the leakage path extends through the sealing gap between the first valve space and the second valve space.

5. The control valve according to claim 3, wherein in order to set the leakage path, the sealing gap between the first valve space and the second valve space is embodied so as to be larger than a sealing gap between the second valve space and the third valve space and/or larger than a sealing gap between the first valve space and the third valve space.

6. The control valve according to claim 1, wherein the second valve space is connected to an outlet.

7. The control valve according to claim 1, wherein the leakage path is formed by a gap between an inner wall of the piston space and an outer wall of the control piston, and/or a structure in the region of the outer wall of the control piston which separates the first valve space from the second valve space, and/or a structure on the inner wall of the piston space in a shifting region of the leakage path, and/or at least one passage opening, in the control piston, which fluidically connects the first valve space to the second valve space, and/or at least one passage opening, in the valve housing, which fluidically connects the first valve space, and/or the inlet which feeds into the first valve space, to the second valve space and/or the outlet which feeds into the second valve space.

8. The control valve according to claim 1, wherein the other leakage between the third valve space and the second valve space and/or between the third valve space and the first valve space is a desired leakage via a secondary leakage path defined between the respective valve spaces.

9. The control valve according to claim 1, wherein the desired leakage via the leakage path is at least 1.5 times larger than the other leakage.

10. The control valve according to claim 8, wherein the secondary leakage path is formed by a gap between an inner wall of the piston space and an outer wall of the control piston, and/or a structure in the region of the outer wall of the control piston which separates the first valve space from the third valve space, and/or a structure in the region of the outer wall of the control piston which separates the second valve space from the third valve space, and/or a structure on the inner wall of the piston space in a shifting region of the other leakage path, and/or at least one passage opening, in the control piston, which fluidically connects the first valve space to the third valve space, and/or at least one passage opening, in the control piston, which fluidically connects the second valve space to the third valve space, and/or at least one passage opening, in the valve housing, which fluidically connects the first valve space, and/or the inlet which feeds into the first valve space, to the third valve space and/or the inlet which feeds into the third valve space, and/or at least one passage opening, in the valve housing, which fluidically connects the second valve space, and/or the outlet which feeds into the second valve space, to the third valve space and/or the inlet which feeds into the third valve space.

11. The control valve according to claim 1, further comprising a restoring means which acts on the control piston counter to a fluid pressure prevailing in the first valve space.

12. The control valve according to claim 11, wherein the restoring means is a valve spring.

13. The control valve according to claim 1, further comprising a restoring means which acts on the control piston counter to a fluid pressure prevailing in the third valve space.

14. The control valve according to claim 1, wherein the fluid is permanently applied to at least one of the first valve space and the third valve space.

15. The control valve according to claim 1, wherein the fluid pressure can be selectively applied via a controlling means to at least one of the first valve space and the third valve space.

16. The control valve according to claim 15, wherein the controlling means is coupled to a superordinate controller in order to either apply pressurised fluid to said at least one of the first valve space and the third valve space or to relieve said at least one of the first valve space and the third valve space of pressure, as a function of control signals of the superordinate controller.

17. The control valve according to claim 16, wherein the superordinate controller is an engine controller of an engine of the vehicle.

18. A motor vehicle device comprising an adjustable rotary pump which comprises an adjusting means, for adjusting a delivery volume of the rotary pump, and the control valve according to claim 1, using which a pressure for adjusting the delivery volume can be controlled or governed.

19. The motor vehicle device according to claim 18, wherein the first valve space of the control valve can be connected to and separated from a high-pressure side of the rotary pump via a controlling means.

20. The motor vehicle device according to claim 18, wherein the second valve space is permanently connected to a reservoir or a suction side of the rotary pump.

21. The motor vehicle device according to claim 18, wherein the third valve space of the control valve is permanently connected to a high-pressure side of the rotary pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An example embodiment of the invention is described below on the basis of figures. Features disclosed by the example embodiment, each individually and in any combination of features, advantageously develop the subject-matter of the claims and the subject-matter of the aspects above and also the embodiments described at the beginning. There is shown:

(2) FIG. 1 shows a control piston of a control valve;

(3) FIG. 2 is partially, a section through an adjustable rotary pump comprising a control valve which comprises a control piston in accordance with FIG. 1, wherein the rotary pump is at full delivery;

(4) FIG. 3 is the section in FIG. 2, wherein the rotary pump is throttled; and

(5) FIG. 4 is a schematic circuit diagram of a motor vehicle device comprising the adjustable rotary pump comprising the control valve.

(6) FIG. 4A is a schematic circuit diagram of an alternative motor vehicle device comprising the adjustable rotary pump comprising the control valve including a superordinate controller.

(7) FIG. 5A is a cross-sectional view illustrating a structure in the region of the outer wall of the control piston.

(8) FIG. 5B is a cross-sectional view illustrating a structure on the inner wall of the piston space.

(9) FIG. 5C is a cross-sectional view illustrating a passage opening in the control piston.

(10) FIG. 5D is a cross-sectional view illustrating a passage opening in the valve housing.

DETAILED DESCRIPTION OF THE INVENTION

(11) FIG. 1 shows, in isolation, an example embodiment of a control piston 4 for a control valve 1 (not shown). The control piston 4 comprises a first sealing portion 47, a second sealing portion 48 and a third sealing portion 49 which exhibit a diameter D1, D2, D3 which is larger than the diameters of the control piston 4 in front of, between and behind the sealing portions 47, 48, 49 in the first, second, third and fourth control piston portions 41, 42, 43, 44. The first sealing portion 47 and the second sealing portion 48 delineate the second control piston portion 42 in the axial direction of the control piston 4; the second sealing portion 48 and the third sealing portion 49 delineate the third control piston portion 43 in the axial direction. In this example embodiment, the control piston portion 41 likewise forms a sealing portion 50 exhibiting a diameter D4. The control piston 4 comprises a first active surface W1, a second active surface W2 and a third active surface W3. In this example embodiment, pressure fluid can only be applied to the first active surface W1 and the second active surface W2. The third active surface W3 is attached to an outlet, a reservoir or a suction side. It is in principle conceivable for pressure fluid to be able to be applied to all three active surfaces W1, W2, W3.

(12) In accordance with the invention, the diameters D1, D2, D3 are different, i.e. at least one of the diameters D1, D2, D3 is smaller than one or more of the other diameters D1, D2, D3, such that if the control piston 4 is arranged in a piston space 3 exhibiting a diameter which is constant in a shifting region of at least two adjacent sealing portions 47, 48, 49 of the control piston 4, the sealing portion or portions 47, 48, 49 exhibiting the smaller diameter allow a desired or specific leakage, preferably through a permanently open leakage path L1, from one of the control piston portions 41, 42, 43, 44 into one of the adjacent control piston portions 41, 42, 43, 44. A desired leakage within the meaning of the invention can of course also be established when the diameter of the piston space 3 is different in regions of the sealing portions 47, 48, 49, 50.

(13) In order to achieve the desired leakage, one or more of the sealing portions 47, 48, 49 can for example also solely or additionally comprise at least one groove on the outer circumference of the sealing portion or portions 47, 48, 49, a structure on the radially outer circumferential surface of the sealing portion or portions 47, 48, 49 which enables fluid to pass through, at least one passage bore or another fluid path for the desired leakage between two adjacent control piston portions 41, 42, 43, 44.

(14) The subsequent figures show an example embodiment of a control valve 1 comprising a control piston 4 in accordance with FIG. 1. So as not to overburden the figures with reference signs, not all the reference signs from FIG. 1 are repeated. Where there is doubt, FIG. 1 may be adduced for better comprehension.

(15) FIG. 2 shows a control valve 1 for controlling or governing an adjustable rotary pump 6 of a motor vehicle. The control valve 1 comprises a valve housing 2 and a piston space 3 in which the control piston 4 is mounted such that it can be shifted. In this example embodiment, a pump housing of the rotary pump 6 also forms the valve housing 2. In the example embodiment, the piston space 3 is formed from a first piston space portion 31 exhibiting a constant inner diameter, and a second piston space portion 32 exhibiting a constant inner diameter, wherein the inner diameter of the second piston space portion 32 is smaller than the inner diameter of the first piston space portion 31. With FIG. 1 in mind, the inner diameter of the first piston space portion 31 corresponds to the maximum diameter D1, D2, D3 of the sealing portion or portions 47, 48, 49.

(16) The control valve 1 comprises a restoring means 5 which presses the control piston 4 into a first end position which it for example assumes when the rotary pump 6 is at a stop and in which the rotary pump 6 (which is only partially shown) is for example set to full delivery. In the example embodiment shown, the restoring means 5 is a spring element and/or valve spring 5 and advantageously a pressure spring in the form of a spiral spring. The control valve 1 comprises multiple inlets and outlets, of which however only those which are important to better understanding the invention are provided with reference signs and described in more detail in the following. The functionality of the control valve 1 is well known to the person skilled in the art, such that a detailed description is unnecessary.

(17) The control valve 1 or, respectively, the piston space 3 is divided by the control piston 4 into five valve spaces R1, R2, R3, R3, R4 in the example embodiment shown. The valve spaces R3, R3 are permanently connected to a pressure side of the rotary pump 6 via the inlets E2 and E2, respectively. The valve space R2 is permanently connected to a reservoir 10 or the suction region of the rotary pump 6 via an outlet O1. The valve space R1 is connected to a fluid supply, via which fluid of differing pressure can be supplied, via the inlet E1. The valve space R1 can be connected up to the pressure side of the rotary pump 6. The pressure in the valve spaces R3 and R1 acts against the force of the restoring means 5 and can move the control piston 4 linearly within the piston space 3 towards the valve space R4 and hold it in a position assumed.

(18) The first leakage path L1, which enables a desired transition of fluid from the valve space R1 into the valve space R2 and thus permanently connects the valve space R1, with throttle, to the outlet O1, is indicated in FIG. 2. The second leakage path L2, whichas already described in the general sectionneed not be a desired leakage path but can rather be formed solely by the permissible manufacturing tolerances, connects the valve space R3 to the valve space R2, wherein the leakage via the first leakage path L1 is larger than the leakage via the second leakage path L2. At least one and a half times as much fluid, preferably at least twice as much fluid, can flow from the valve space R1 into the valve space R2 via the first leakage path L1 as from the valve space R3 into the valve space R2 via the second leakage path L2, given the same operational conditions and the same time.

(19) FIG. 3 shows the control valve 1 comprising the control piston 4, in a second end position or just short of the second end position in which the restoring means 5 is maximally compressed by the pressure fluid flowing into the piston space 3. All other essential features to be read into the invention remain unaltered and need not therefore be repeated.

(20) FIG. 4 shows a schematic circuit diagram of a motor vehicle device comprising the adjustable displacement pump 6, for example a vane cell pump, pendulum-slider pump or an internal or external gear pump, comprising the control valve 1 and a controlling means 9 for controlling the control valve 1. The motor vehicle device is provided for lubricating and/or cooling an engine 8, preferably an internal combustion engine, or for supplying a transmission of the motor vehicle. The controlling means 9 is embodied as a magnetic valve. It is embodied as a PWM valve. The controlling means 9 sets a secondary pressure which acts on the adjusting means 7 of the rotary pump 6 via the control valve 1. The controlling means 9 connects the valve space R1 of the control valve 1 to the pressure side of the rotary pump 6 or separates the valve space R1 of the control valve 1 from the pressure side of the rotary pump 6.

(21) A part of the pressure fluid is channeled from the pressure side of the pump 6 to a consumer (not shown) via a conduit S1 and flows partially via a conduit S2 directly to the control valve 1, where it flows into the valve spaces R3, R3 through the inlets E2 and E2. Another part of the pressure fluid is channeled via the conduit S3 to the controlling means 9 which, when open, channels this part of the pressure fluid through the inlet E1 into the valve space R1 and, when closed, separates the pressure side of the rotary pump 6 from the inlet E1. An active surface for the pressure of the pressure fluid on the control piston 4 is therefore increased when the controlling means 9 is open, such that this pressure is greater than the pressure of the restoring means 5, thus enabling the control piston 4 to be moved from its first end position in FIG. 2 into its second end position in FIG. 3.

LIST OF REFERENCE SIGNS

(22) 1 control valve 2 valve housing 3 piston space 31 piston space portion 32 piston space portion 4 control piston 41 control piston portion 42 control piston portion 43 control piston portion 44 control piston portion 47 sealing portion 48 sealing portion 49 sealing portion 50 sealing portion 5 restoring means, valve spring 6 rotary pump 7 adjusting means 8 engine 9 controlling means 10 reservoir D1 diameter D2 diameter D3 diameter D4 diameter W1 active surface W2 active surface W3 active surface E1 inlet E2 inlet E2 inlet L1 leakage path L2 leakage path O1 outlet R1 valve space R2 valve space R3 valve space R3 valve space R4 valve space S1 conduit S2 conduit S3 conduit