MAGNET ASSEMBLY FOR AN ACTUATION AND/OR DELIVERY ASSEMBLY, AND METHOD FOR PRODUCING THE MAGNET ASSEMBLY

Abstract

The invention relates to a magnet assembly (1) for an actuation and/or delivery assembly, in particular a delivery pump for an operating medium/additive in a motor vehicle, comprising an annular magnetic coil (2) and a pole body (3) which at least partly engages into the magnetic coil (2) and on which a compression spring (4) is directly or indirectly supported in order to restore an armature (5) that can carry out a stroke movement. According to the invention, the pole body (3) has a magnetic throttle point (6) in a hollow cylindrical section for guiding the armature (5), wherein the magnetic permeability of the pole body (3) is reduced in the region of the throttle point. The invention additionally relates to a method for producing a magnet assembly (1) according to the invention

Claims

1. A magnet assembly (1) for an actuation and/or delivery assembly, the magnet assembly comprising an annular magnet coil (2), a pole body (3) which engages at least in sections into the magnet coil (2), and a compression spring (4) supported directly or indirectly on the pole body (3) for restoring an armature (5) which can be moved with a reciprocating motion, wherein the pole body (3) has a magnetic choke point (6) in a hollow-cylindrical section for guiding the armature (5), and wherein the magnetic permeability of the pole body (3) is reduced in a region of the magnetic choke point (6).

2. The magnet assembly (1) as claimed in claim 1, characterized in that, in order to configure the magnetic choke point (6), the pole body (3) has a hollow-cylindrical section with a reduced external diameter (D.sub.2).

3. The magnet assembly (1) as claimed in claim 1, characterized in that, in the region of the magnetic choke point (6), the pole body (3) has a microstructure, into which constituent parts of at least one chemical element are embedded.

4. The magnet assembly (1) as claimed in claim 1, characterized in that the pole body (3) protrudes beyond the magnet coil (2) on both sides.

5. The magnet assembly (1) as claimed in claim 1, characterized in that the pole body (3) delimits a coil receptacle space (10) together with a magnetic sleeve (8) which is arranged radially on an outside in relation to the magnet coil (2) and together with a return ring (9).

6. The magnet assembly (1) as claimed in claim 1, characterized in that the pole body (3) configures a stroke stop (11) for the armature (5).

7. A method for producing a magnet assembly (1) as claimed in claim 1, the method comprising subjecting the pole body (3) to a chemical treatment in order to reduce the magnetic permeability in the region of the magnetic choke point (6), and embedding constituent parts of at least one chemical element (14) into a microstructure of the pole body (3).

8. The method as claimed in claim 7, characterized in that, by way of the embedding of the constituent parts of the at least one chemical element (14) into the microstructure of the pole body (3), additional separating layers are configured which reduce the magnetic permeability of the pole body (3) in the region of the magnetic choke point (6).

9. The magnet assembly (1) as claimed in claim 1, characterized in that, in order to configure the magnetic choke point (6), the pole body (3) has a hollow-cylindrical section with a modified microstructure.

10. The magnet assembly (1) as claimed in claim 9, characterized in that, in order to configure the magnetic choke point (6), the pole body (3) has a hollow-cylindrical section with a reduced external diameter (D.sub.2).

11. The magnet assembly (1) as claimed in claim 1, characterized in that, in the region of the magnetic choke point (6), the pole body (3) has a microstructure, into which constituent parts of nitrogen are embedded.

12. The magnet assembly (1) as claimed in claim 1, characterized in that the pole body (3) has a radially outwardly extending annular collar (7) for axially supporting the magnet coil (2).

13. The magnet assembly (1) as claimed in claim 12, characterized in that the pole body (3) protrudes beyond the magnet coil (2) on both sides.

14. The magnet assembly (1) as claimed in claim 12, characterized in that the pole body (3) delimits a coil receptacle space (10) together with a magnetic sleeve (8) which is arranged radially on an outside in relation to the magnet coil (2) and together with a return ring (9) which is arranged at an end of the pole body (3), which end lies opposite the annular collar (7).

15. The magnet assembly (1) as claimed in claim 1, characterized in that the pole body (3) has a central recess (12) for receiving the compression spring (4) in sections.

16. The magnet assembly (1) as claimed in claim 15, characterized in that the pole body (3) configures a stroke stop (11) for the armature (5).

17. The method as claimed in claim 7, wherein the chemical element (14) is nitrogen.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One preferred embodiment of the invention will be described in greater detail in the following text on the basis of the appended drawings, in which:

[0019] FIG. 1 shows a diagrammatic longitudinal section through a magnet assembly according to the invention, and

[0020] FIG. 2 shows a diagrammatic longitudinal section through the pole body of the magnet assembly from FIG. 1.

DETAILED DESCRIPTION

[0021] The magnet assembly 1 according to the invention which is shown in FIG. 1 comprises an annular magnet coil 2 which surrounds a pole body 3 which protrudes beyond the magnet coil 2 on both sides. Here, the magnet coil 2 is supported on an annular collar 7 of the pole body 3. The magnet coil 2 is surrounded radially on the outside by a magnetic sleeve 8 which, together with the pole body 3 and a return ring 9, delimits a coil receptacle space 10. To this end, the return ring 9 is placed onto the pole body 3, to be precise on an end of the pole body 3, which end lies opposite the annular collar 7.

[0022] The pole body 3 has a hollow-cylindrical section which serves to guide an armature 5 which can be moved with a reciprocating motion. At the same time, the pole body 3 configures a stroke stop 11 for the armature 5. In the region of the stroke stop 11, the pole body 3 has a central recess 12 for receiving a compression spring 4 which is supported at the other end on the armature 5 and serves to restore the armature 5. In this way, the compression spring 4 is also guided by way of the pole body 3.

[0023] Offset errors are avoided on account of the guidance of the armature 5 by way of the pole body 3 of single-piece configuration, with the result that optimum armature running is ensured. Furthermore, the manufacturing and/or assembly complexity is decreased. In order at the same time to achieve an optimum build-up of force at the armature 5, the pole body 3 has a magnetic choke point 6 in the region of the hollow-cylindrical section which serves to guide the armature 5. The magnetic choke point 6 is formed by way of a reduced wall thickness and a modified microstructure of the pole body 3. If the hollow-cylindrical section has an external diameter D.sub.1, the latter is reduced in the region of the magnetic choke point 6 to an external diameter D.sub.2. Furthermore, the microstructure of the pole body 3 is modified in the region of the magnetic choke point 6 by way of a chemical treatment. To this end, the pole body 3 has been subjected to a treatment with at least one chemical element 14, such as nitrogen, with the result that constituent parts of the chemical element 14 diffuse into the microstructure of the pole body 3. This leads to the configuration of additional separating layers within the microstructure, which separating layers reduce the magnetic permeability of the pole body 3 in the region of the magnetic choke point 6.

[0024] As shown diagrammatically in FIG. 2, the saturation of the microstructure of the pole body 3 with the at least one chemical element 14 is dependent on the wall thickness of the pole body 3. Saturation of thin-walled regions can be brought about more rapidly, with the result that the configuration of additional separating layers can be limited substantially to the region of the magnetic choke point 6. Otherwise, the magnetic permeability of the pole body 3 is accordingly not influenced or not influenced appreciably.

[0025] Accordingly, the magnetic force of the magnet assembly 1 according to the invention remains unchanged or rises, since bypass losses are reduced. That is to say, high magnetic forces which act on the armature 5 can be achieved, which magnetic forces can be used, for example, for actuating a valve member 13 which is coupled to the armature 5 (see FIG. 1).