Pressure control valve for a fuel injection system

Abstract

A pressure control valve for a fuel injection system, in particular a common-rail injection system, for controlling pressure in a high-pressure fuel reservoir, includes a magnetic actuator configured to actuate a spherical valve closing element. The magnetic actuator interacts with a reciprocatingly displaceable armature that is connected to an armature pin in order to transmit a force of the magnetic actuator to the spherical valve closing element. At least one of the spherical valve closing element and the armature pin is axially displaceably guided in a valve piece which forms a valve seat configured to interact with the spherical valve closing element.

Claims

1. A pressure control valve for a fuel injection system configured to control a pressure in a high-pressure fuel accumulator, comprising: a spherical valve closing element; a valve piece defining a valve seat with a conical form, the valve seat configured to interact with the spherical valve closing element, the valve piece formed as a one-piece, unitary body; and a solenoid actuator configured to actuate the spherical valve closing element, and to interact with an armature configured to perform a stroke movement, the armature connected to an armature pin and configured to transmit a force of the solenoid actuator to the spherical valve closing element, wherein the valve piece further defines a first guide region and a second guide region arranged axially above the first guide region, the spherical valve closing element guided in an axially displaceable direction in the valve piece by the first guide region, the armature pin guided in the axially displaceable direction in the valve piece by the second guide region, wherein the first guide region has at least two first guide surfaces configured to delimit a radial movement of the spherical valve closing element, wherein the second guide region has at least two second guide surfaces configured to delimit a radial movement of the armature pin, and wherein the at least two first guide surfaces directly adjoin the valve seat via first radially running webs.

2. The pressure control valve as claimed in claim 1, wherein: the at least two second guide surfaces are formed on second radially running webs, and the first radially running webs and the second radially running webs delimit flow ducts.

3. The pressure control valve as claimed in claim 2, wherein at least a part of the flow ducts is hydraulically connected to an armature chamber.

4. The pressure control valve as claimed in claim 1, wherein in a cross section of the valve piece, the at least two first guide surfaces form tangents to an outer diameter of the spherical valve closing element, and the at least two second guide surfaces form tangents to an outer diameter of the armature pin.

5. The pressure control valve as claimed in claim 1, wherein the valve piece is a metal injection molded part.

6. The pressure control valve as claimed in claim 1, wherein the valve piece has a biting edge on a support surface averted from the valve seat.

7. The pressure control valve as claimed in claim 1, wherein the pressure control valve is configured as a 2/2 directional valve.

8. The pressure control valve as claimed in claim 1, wherein: the at least two second guide surfaces are formed on second radially running webs, and the first radially running webs are connected to the second radially running webs via a conical surface of the valve seat.

9. The pressure control valve as claimed in claim 1, wherein: the at least two second guide surfaces are formed on second radially running webs, and the first radially running webs and the second radially running webs are arranged at uniform angular intervals with respect to one another.

10. The pressure control valve as claimed in claim 9, wherein the first radially running webs and the second radially running webs delimit flow ducts.

11. The pressure control valve as claimed in claim 2, further comprising a valve housing interposed between the valve piece and the armature, the valve housing formed as a one-piece, unitary body, wherein the valve piece defines a valve chamber and the valve housing defines an armature chamber spaced from valve chamber, the armature chamber hydraulically connected to the valve chamber via the flow ducts.

12. The pressure control valve as claimed in claim 4, wherein: the spherical valve closing element has a punctiform contact region with at least one of the at least two first guide surfaces when the spherical valve closing element is guided by the first guide region, and the armature pin has a linear contact region with at least one of the at least two second guide surfaces when the armature pin is guided by the second guide region.

13. A pressure control valve for a fuel injection system configured to control a pressure in a high-pressure fuel accumulator, comprising: a spherical valve closing element; a valve piece defining a valve seat with a conical form, the valve seat configured to interact with the spherical valve closing element, the valve piece formed as a one-piece, unitary body; and a solenoid actuator configured to actuate the spherical valve closing element, and to interact with an armature configured to perform a stroke movement, the armature connected to an armature pin and configured to transmit a force of the solenoid actuator to the spherical valve closing element, wherein the valve piece further defines a first guide region and a second guide region arranged axially above the first guide region, the spherical valve closing element guided in an axially displaceable direction in the valve piece by the first guide region, the armature pin guided in the axially displaceable direction in the valve piece by the second guide region, wherein the first guide region has at least two first guide surfaces configured to delimit a radial movement clearance of the spherical valve closing element, wherein the second guide region has at least two second guide surfaces configured to delimit a radial movement clearance of the armature pin, wherein the at least two first guide surfaces directly adjoin the valve seat via first radially running webs, wherein the at least two second guide surfaces are formed on second radially running webs, and wherein the first radially running webs and the second radially running webs are arranged at uniform angular intervals with respect to one another.

14. A pressure control valve for a fuel injection system configured to control a pressure in a high-pressure fuel accumulator, comprising: a spherical valve closing element; a valve piece defining a valve seat with a conical form, the valve seat configured to interact with the spherical valve closing element, the valve piece formed as a one-piece, unitary body; a solenoid actuator configured to actuate the spherical valve closing element, and to interact with an armature configured to perform a stroke movement, the armature connected to an armature pin and configured to transmit a force of the solenoid actuator to the spherical valve closing element; and a valve housing interposed between the valve piece and the armature, the valve housing formed as a one-piece, unitary body, wherein the valve piece further defines a first guide region and a second guide region arranged axially above the first guide region, the spherical valve closing element guided in an axially displaceable direction in the valve piece by the first guide region, the armature pin guided in the axially displaceable direction in the valve piece by the second guide region, wherein the first guide region has at least two first guide surfaces configured to delimit a radial movement clearance of the spherical valve closing element, and wherein the second guide region has at least two second guide surfaces configured to delimit a radial movement clearance of the armature pin, wherein the at least two first guide surfaces directly adjoin the valve seat via first radially running webs, wherein the at least two second guide surfaces are formed on second radially running webs, wherein the first radially running webs and the second radially running webs delimit flow ducts, and wherein the valve piece defines a valve chamber and the valve housing defines an armature chamber spaced from valve chamber, the armature chamber hydraulically connected to the valve chamber via the flow ducts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A preferred embodiment will be discussed in more detail below on the basis of the appended drawings, in which:

(2) FIG. 1 shows a longitudinal section through a preferred embodiment of a pressure control valve according to the disclosure, and

(3) FIG. 2 shows an enlarged detail from FIG. 1 in the region of the valve piece.

(4) FIG. 3 shows a further enlarged detail from FIG. 1 in the region of the spherical valve closing element.

DETAILED DESCRIPTION

(5) The pressure control valve illustrated in FIG. 1 comprises a solenoid actuator 1 which has an annular magnet coil 17 and which interacts with an armature 3 which can perform a stroke movement, and which in the present case is in the form of a solenoid plunger. The armature 3 is connected to an armature pin 4 which, as force transmission element, transmits the force of the solenoid actuator 1 to a spherical valve closing element 2 when the solenoid actuator 1 is activated, that is to say the magnet coil 17 is energized. In this case, the armature 3 including the armature pin 4 are moved, counter to the spring force of a spring 15, in the direction of the spherical valve closing element 2. There, the armature pin 4 presses the spherical valve closing element 2 against a conical valve seat 6, such that the pressure control valve is closed and no connection between a high-pressure accumulator 13 and a return port 16 is produced. If the pressure in the high-pressure accumulator 13 rises beyond a predefined threshold, the energization of the magnet coil 17 is ended, such that the spring force of the spring 15 effects a return movement of the armature 3 including the armature pin 4 and the valve is opened by way of the pressure acting on the spherical valve closing element.

(6) In the present case, the pressure control valve is received in a stepped bore 18 of the high-pressure accumulator 13 and is connected to the latter by way of a screw connection 19. For this purpose, there is formed on a valve housing 14 of the pressure control valve an external thread which can be connected to an internal thread of the stepped bore 18. By way of the screw connection 19, the pressure control valve can be axially preloaded against the high-pressure accumulator, wherein the pressure control valve is supported by way of a support surface 11 of a valve piece 5 against a step of the stepped bore 18. A biting edge 12 formed in the region of the support surface 11 seals off the high-pressure accumulator 13 to the outside.

(7) As can be seen from FIG. 2, the valve piece 5, which also forms the valve seat 6, has a first guide region a for the guidance of the spherical valve closing element 2 and has a second guide region b for the guidance of the armature pin 4. The guidance is effected in each case by way of five guide surfaces 7, 20 which are each formed by five webs 8, 22, said webs being arranged in a star shape around the valve seat 6. The five webs 8, 22 of the guide regions a, b are arranged in each case at uniform angular intervals with respect to one another, such that, between the webs 8, 22, there are formed flow ducts 9 which are hydraulically connected (see FIG. 1) to an armature chamber 10. Since the spherical valve closing element 2 has a smaller diameter than the armature pin 4, the guide surfaces 7 for guiding the spherical valve closing element 2 are situated radially further toward the inside than the guide surfaces 20 which serve for the guidance of the armature pin 4. The guide surfaces 20 for the guidance of the armature pin 4 are formed by separate webs 22 which, in the present case, are arranged in the same angular positions as the webs 8 for forming the guide surfaces 7 for guiding the spherical valve closing element 2. In this way, the flow ducts 9 formed in each case between the webs 8, 22 overlap.

(8) As can also be seen from FIG. 2, the webs 8 including the guide surfaces 7 of the guide region a directly adjoin the conical surface of the valve seat 6. In effect, said webs rise out of the valve seat surface. The conical surface of the valve seat 6 extends beyond this, such that the webs 22 of the guide region b also rise out of the conical surface of the valve seat 6. Accordingly, the webs 8, 22 of the two guide regions a, b are connected by way of the conical surface.