Solenoid Valve for Controlling the Braking Pressure of a Wheel Brake and Tool for Producing Its Valve Element

Abstract

A solenoid valve for controlling the braking pressure of a wheel brake of a slip-controllable hydraulic brake system of a motor vehicle includes an armature, a valve insert, a valve seat, a valve element, and a spring device. The valve element is arranged in the valve insert in a longitudinally displaceable manner and acts together with the valve seat. The spring applies a force acting in the direction of opening with respect to the valve seat to the valve element in the installed position. The valve element can be actuated by an electromagnetic actuator in the closing direction with respect to the valve seat. The valve element is arranged between an anchor and the valve seat and is operatively connected to the anchor. A front face of the valve element facing the anchor has at least one projection and the projection defines a point of contact with the anchor.

Claims

1. A solenoid valve for controlling a braking pressure of a wheel brake of a slip-controllable hydraulic brake system of a motor vehicle, comprising: an armature; a valve insert; a valve seat a valve element arranged at least partially in the valve insert in a longitudinally displaceable manner and configured to cooperate with the valve seat, the valve element arranged between the armature and the valve seat, configured to be actuated by an electromagnetic actuator in a closing direction relative to the valve seat, and operatively connected to the armature; and a spring device configured to load the valve element with a force component acting in an opening direction relative to the valve seat when the valve element is in an installed position, wherein an end face of the valve element facing the armature includes at least one protrusion, and wherein the at least one protrusion defines a point of contact with the armature.

2. The solenoid valve as claimed in claim 1, wherein: the at least one protrusion is configured as an interrupted ring; or the at least one protrusion is configured as a part region of an annular element; or the at least one protrusion is configured as points.

3. The solenoid valve as claimed in claim 1, wherein the at least one protrusion includes a plurality of protrusions positioned in a circumferential direction on the end face of the valve element.

4. The solenoid valve as claimed in claim 1, wherein the at least one protrusion includes a plurality of protrusions positioned radially at the same distance from a central axis of the valve element.

5. The solenoid valve as claimed in claim 1, wherein the at least one protrusion includes a plurality of protrusions arranged spaced apart from each other circumferentially on the end face of the valve element.

6. The solenoid valve as claimed in claim 1, wherein the at least one protrusion includes a plurality of protrusions positioned on the end face of the valve element and symmetrically distributed relative to the central axis.

7. The solenoid valve as claimed in claim 1, wherein the at least one protrusion includes a plurality of protrusions positioned on an outer edge of the end face of the valve element.

8. The solenoid valve as claimed in claim 1, wherein the at least one protrusion includes three protrusions.

9. The solenoid valve as claimed in claim 1, wherein: the valve element includes a plurality of fins; and one protrusion of the at least one protrusion is arranged on each fin of the plurality of fins.

10. The solenoid valve as claimed in claim 1, wherein a height of the at least one protrusion is configured such that the at least one protrusion compensates for a defined surface unevenness.

11. The solenoid valve as claimed in claim 1, wherein an area of the at least one protrusion is configured as small as possible and guarantees a permanent resistance to a force-loaded application of the valve element on the armature.

12. The solenoid valve as claimed in claim 1, wherein a tool is configured to form the valve element such that the end face of the valve element facing the armature includes the at least one protrusion.

13. The solenoid valve as claimed in claim 10, wherein the defined surface unevenness is a defined surface unevenness and an additional safety allowance.

Description

[0039] The drawings show:

[0040] FIG. 1 a diagrammatic sectional view of a conventional solenoid valve; and

[0041] FIG. 2 a diagrammatic cause-and-effect chain with regard to the accuracy of pressure setting and the armature tilt angle; and

[0042] FIG. 3a a diagrammatic view from the top of an exemplary embodiment of a valve element with formed contact points, and

[0043] FIG. 3b a diagrammatic view from the side of an exemplary embodiment of the valve element with formed contact points.

[0044] FIG. 1 shows a diagrammatic sectional view of a conventional solenoid valve. This has already been described as the prior art.

[0045] FIG. 2 furthermore shows diagrammatically a cause-and-effect chain. In the depictions, the top left shows possible inaccuracies in the individual components. Such inaccuracies may lead to tilting, e.g. an oblique positioning of the armature relative to the valve insert for example. This is shown at the top right of the depiction. On use of the valve, furthermore the armature and/or valve element may rotate. This again leads to a varying oblique positioning of the armature e.g. relative to the valve insert. Varying oblique positions of the armature however cause a variation in the magnetic force acting on the armature. This is shown at the bottom right of the depiction. The varying magnetic force acting on the armature in turn leads to a different current/pressure characteristic of the valve, as shown in the bottom left in the depiction. Simple unevennesses in the components thus lead to different performance characteristics for different valvesand different characteristics are produced in one and the same valve during operation of the valve.

[0046] FIGS. 3a and 3b show embodiments to solve the problem. FIG. 3a shows, in a direct top view, defined contact points 6.3 on the end face of the valve element 6. The contact points 6.3 are defined and formed on the end face 6.4 of the valve element 6 pointing towards the armature 4. One contact point 6.3 is made on each fin of the valve element 6. The contact points 6.3 are positioned on the outer edge of the end face 6.4 but slightly set back from the outer edge. The contact points 6.3 are longer in the circumferential direction than in the radial direction. The radial edges of the contact points 6.3 are oriented towards the central axis 6.5 of the valve element 6.

[0047] FIG. 3b shows the exemplary embodiment in a side view. The valve element 6 is also depicted. It is clear here that the contact points 6.3 are formed on the end face 6.4 of the valve element 6 facing the armature 4. Furthermore, the spacing of the contact points 6.3 is also shown. The depicted height of the contact points 6.3 serves for better identification. Furthermore, the closing element 6.1, the main sealing element 6.2 and the spring device 7 are also depicted.