Valve of a piston pump having a two-part closing body

Abstract

A valve of a piston pump for a vehicle brake system having a closing body which is resiliently preloaded against a sealing seat. The closing body is formed in two parts with a damping piston and a closing element inserted therein. The damping piston is axially displaceably guided in a cylindrical piston guide. At least one flow channel is provided between the damping piston and the piston guide. The at least one flow channel is configured such that fluid can flow around the damping piston in the longitudinal direction thereof through the at least one flow channel.

Claims

1. A valve of a piston pump for a vehicle brake system, the valve comprising: a cylinder having a circular outflow opening at a first end thereof, the outflow opening being surrounded by a sealing seat; a pump cover which encloses the first end, the pump cover forming a cylindrical piston guide; a closing body resiliently preloaded against the sealing seat, the closing body formed in two parts with a damping piston and a closing element inserted in the damping piston, wherein the damping piston is axially displaceably guided in the cylindrical piston guide, wherein at least one flow channel is provided between an outer circumferential surface of the damping piston and the piston guide, and wherein the at least one flow channel is configured to enable fluid to flow around the damping piston in a longitudinal direction of the damping piston through the at least one flow channel.

2. The valve according to claim 1, wherein the at least one flow channel is a cutout in the damping piston.

3. The valve according to claim 2, wherein the cutout is a radially directed slot in the damping piston.

4. The valve according to claim 2, wherein the cutout includes four cutouts provided in a uniformly distributed manner over a circumference of the damping piston.

5. The valve according to claim 1, wherein the at least one flow channel is a cutout in the piston guide.

6. The valve according to claim 5, wherein the cutout is a radially directed groove in the piston guide.

7. The valve according to claim 5, wherein the cutout includes four cutouts provided in a uniformly distributed manner over a circumference of the piston guide.

8. The valve according to claim 1, wherein the valve is configured for use on a piston pump of a hydraulic vehicle brake system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The solution according to the disclosure will be explained in more detail below by way of example with reference to the appended schematic drawings, in which:

(2) FIG. 1 shows a partial longitudinal section of a first exemplary embodiment of a piston pump according to the disclosure,

(3) FIG. 2 shows a perspective view of the closing body according to FIG. 1,

(4) FIG. 3 shows the section III-III according to FIG. 1,

(5) FIG. 4 shows the longitudinal section according to FIG. 1 of a second exemplary embodiment of a piston pump according to the disclosure,

(6) FIG. 5 shows a perspective view of the closing body according to FIG. 4, and

(7) FIG. 6 shows the section VI-VI according to FIG. 4.

DETAILED DESCRIPTION

(8) FIGS. 1 to 3 illustrate a first piston pump 10 for a hydraulic vehicle brake system (not shown further) which serves to produce a fluid pressure for brake fluid within the vehicle brake system. For this purpose, the piston pump 10 has a cup-shaped cylinder 12 in which a piston (not shown) is displaceably mounted against a helical spring 14. The piston delivers brake fluid through a circular outflow opening 16 formed in the bottom region of the cylinder 12. The outflow opening 16 is surrounded by a valve seat or sealing seat 18 which is part of an outlet valve 20. A helical spring 24 is supported on a pump cover 26 which encloses the cylinder 12 at the end side. A cylindrical piston guide 28 is formed by the pump cover 26. The helical spring 24 presses a two-part closing body 22 against the sealing seat 18. The closing body 22 comprises a damping piston 30 and a mushroom-shaped closing element 32 inserted therein. The damping piston 30 is guided by the piston guide 28. A construction is provided in this way by means of which it is possible to compensate for manufacturing size tolerances in particular between the sealing seat 18 and the closing body 22 in the radial direction. In this case, the closing element 32 bears by its shaft-side end face on the end side of the damping piston 30 and is slightly radially movable. The closing element 32 comprises a bearing head 34 and a shaft 36 which is plugged into the damping piston 30 and protrudes therein.

(9) The closing element 32 has been plugged by its shaft 36 into a central through-opening 38 formed in the damping piston 30 and has a central depression 40 on its head 34 at the end side facing the sealing seat 18. This central depression 40 produces a build-up effect for the inflowing fluid and leads to an improved opening behavior of the outlet valve 20.

(10) The closing element 32 is retained on the damping piston 30 by means of a latching arrangement which, in the exemplary embodiment represented in FIGS. 1 to 3, is formed by a peripheral shoulder 42 formed on the free end of the shaft 36. The diameter of the shoulder 42 is slightly larger than the diameter of the through-opening 38. The remainder of the shaft 36 has a slightly smaller diameter than the through-opening 38. In this way, the closing element 32 is held on the damping piston 30 with radial play, this being ensured in particular by the then radial distance between the shaft 36 and the damping piston 30 surrounding it.

(11) On the end side 44 of the damping piston 30 that faces the closing element 32 there is formed a radially oriented channel 46 through which fluid can flow through below the head 34 into the interior of the damping piston 30 and to its rear side. This fluid contributes to a damping, which can be set in a targeted manner at different operating pressures, of the movement of the damping piston 30. In this case, the damping piston 30 is likewise resiliently preloaded by means of a helical spring 24 at its rear side, said spring being supported on a pump cover 26.

(12) A constriction 48 is formed in the channel 46, forming a throttle. This throttle retards the outflow of fluid into the interior of the damping piston 30 in a targeted manner.

(13) In order to insert the closing element 32 by means of its shaft 36 into the through-opening 38, a phase 50 or 52 is formed both on the free end of the shaft 36 and on the end-side edge of the through-opening 38.

(14) As is represented in FIG. 3, there are provided between the damping piston 30 and the piston guide 28 four flow channels 56 through which fluid can flow around the damping piston 30 in the longitudinal direction thereof. The flow channels are configured in each case as a cutout or as a radially directed slot in the damping piston 30. These slots make it possible for fluid which flows out of the outlet valve 20 to flow around the damping piston 30, with the result that its damping behavior can be influenced in a targeted manner.

(15) FIGS. 4 to 6 illustrate an exemplary embodiment of a two-part closing body 22 according to the disclosure in which the latching arrangement between the damping piston 30 and the mushroom-shaped closing element 32 is produced by means of studs 54. The studs 54 are situated in a distributed manner at regular distances over the circumference of the associated shaft 36 at the location where the shoulder 42 is formed in the exemplary embodiment according to FIGS. 1 to 3.

(16) Furthermore, in the exemplary embodiment according to FIGS. 4 to 6, eight flow channels 56 allowing fluid to flow around the damping piston 30 in the longitudinal direction thereof are provided. The flow channels 56 are in each case configured as a cutout or as a radially outwardly directed groove in the piston guide 28 that extends in the longitudinal direction. Here, the in total eight grooves are arranged spaced apart in a uniformly distributed manner over the inner circumference of the piston guide 28.