SOLENOID VALVE

Abstract

The invention relates to a solenoid valve having an actuator body (17), in which a magnet coil (15) that interacts with a magnet core (16) is arranged and which interacts with an armature (14) that can be moved relative to the magnet core between two end positions and is acted upon by the spring force of an armature spring (13) in a movement direction pointing away from the magnet core (16). The magnet core and the armature have stop surfaces (18a, 18b) which are interrupted by a recess (29) that receives the armature spring. According to the invention, a solenoid valve is provided which is improved with respect to the function of the solenoid valve and the stress on the stop surfaces (18a, 18b) that causes wear. This is achieved in that the magnet core (16) and/or the armature (14) have/has a design (30, 31), in particular a spherical or toroidal design, which reduces the stress on the edges in the region of the stop surfaces (18a, 18b).

Claims

1. A solenoid valve comprising an actuator body (17), having arranged therein a magnet coil (15) which interacts with a magnet core (16), and which interacts with an armature (14) that can be moved relative to the magnet core (16) between two end positions, wherein the armature is acted upon by the spring force of an armature spring (13) in a movement direction pointing away from the magnet core (16), and wherein the magnet core (16) and the armature (14) have stop surfaces (18a, 18b) which are interrupted by a recess (29) that receives the armature spring (13), characterized in that at least one of the magnet core (16) and the armature (14) has a rounded configuration (30, 31, 32) which reduces a stress on edges in a region of the stop surfaces (18a, 18b).

2. The solenoid valve as claimed in claim 1, characterized in that the magnet core (16) and/or the armature (14) has a convex configuration (30) in the region of at least one stopping surface (18a, 18b).

3. The solenoid valve as claimed in claim 1, characterized in that the magnet core (16) and/or the armature (14) has a toroidal configuration (31) in the region of at least one stopping surface (18a, 18b).

4. The solenoid valve as claimed in claim 1, characterized in that the stopping surfaces (18a, 18b) of the magnet core (16) and of the armature (14) have a convex/convex configuration combination.

5. The solenoid valve as claimed in claim 1, characterized in that the stopping surfaces (18a, 18b) of the magnet core (16) and of the armature (14) have a convex/concave configuration combination.

6. The solenoid valve as claimed in claim 1, characterized in that the configuration (30, 31, 32) has a dimension B causing no edge stress on the stopping surfaces (18a, 18b) in a maximum skewed position of the armature (14) relative to the magnet core (16).

7. The solenoid valve as claimed in claim 1, characterized in that the configuration (30, 31, 32) has a dimension B of 50 m to 300 m.

8. The solenoid valve as claimed in 1, characterized in that the stopping surfaces (18a, 18b) are hardened.

9. A high-pressure fuel pump with a solenoid valve as claimed in claim 1.

10. The solenoid valve as claimed in claim 1, wherein the magnet core (16) has a rounded configuration which reduces the stress on edges in the region of the stop surfaces.

11. The solenoid valve as claimed in claim 1, wherein the armature (14) has a rounded configuration which reduces the stress on edges in the region of the stop surfaces.

12. The solenoid valve as claimed in claim 11, wherein the magnet core (16) also has a rounded configuration which reduces the stress on edges in the region of the stop surfaces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Further advantageous embodiments of the invention will be found in the description of the drawings, in which sample embodiments represented in the figures are described more closely.

[0013] There are shown:

[0014] FIG. 1, a longitudinal section through a pump cylinder head region of a high-pressure fuel pump, which is outfitted with a solenoid valve designed as an electromagnetic suction valve,

[0015] FIG. 2, a detail view of the stopping surfaces of a magnet core and of an armature of a solenoid valve with a convex configuration,

[0016] FIG. 3, a detail view of the stopping surfaces of a magnet core and an armature of a solenoid valve, where the armature has a toroidal configuration,

[0017] FIG. 4, a detail view of the stopping surfaces of a magnet core and of an armature of a solenoid valve, where both contact surfaces have a toroidal configuration, and

[0018] FIG. 5, a detail view of the contact surfaces of a magnet core and of an armature of a solenoid valve, where the magnet core has a toroidal convex configuration and the armature has a toroidal concave configuration.

DETAILED DESCRIPTION

[0019] The high-pressure fuel pump shown partly in longitudinal section in FIG. 1 comprises a pump cylinder head 1, in which a solenoid valve is integrated. The solenoid valve comprises an electromagnetically actuatable suction valve 2, which is activated by a solenoid actuator 3. The suction valve 2 serves for the filling of a pump working chamber 4 of the high-pressure fuel pump with fuel. The suction valve 2 comprises a valve tappet 5, which is received and guided with a lifting movement in a bore 6 of the pump cylinder head 1. The pump cylinder head 1 moreover forms a valve seat 7, which interacts in a sealing manner with a valve disk of the valve tappet 5.

[0020] In the region of the bore 6 the pump cylinder head 1 of the high-pressure fuel pump comprises a conical elevation 8, surrounded by a collar 9. The collar 9 is part of the pump cylinder head 1 and bounds a low-pressure chamber 10, which is connected by inlet bores 11 to the bore 6. Hence, the low-pressure chamber 10 is part of a fuel flow path.

[0021] The valve tappet 5 with the valve disk of the suction valve 2 opens directly into the pump working chamber 4. In the closing direction, the valve tappet 5 is subjected to the spring force of a valve spring 12, which is braced on the one hand against the valve tappet 5 or a supporting piece interacting with it and on the other hand against the pump cylinder head 1 in the region of the elevation 8. The spring force of the valve spring 12 is chosen to be less than the spring force of an armature spring 13, which applies force to an armature 14 of the solenoid actuator 3 which can be coupled to the valve tappet 5 and is braced for this purpose against a magnet core 16. The armature spring 13 is installed here in a recess 29 made in the magnet core 16 and the armature 14. The spring force of the armature spring 13 is opposed by the spring force of the valve spring 12, so that the valve spring 12 cannot close the suction valve 2 when the armature spring 13 presses the armature 14 against the valve tappet 5.

[0022] In order to overcome the spring force of the armature spring 13 and close the suction valve 2, the solenoid actuator 3 is provided, comprising a ring-shaped magnet coil 15 and the magnet core 16 placed therein. The magnet core 16 and the magnet coil 15 are installed in an actuator body 17. The magnet core 16 and the armature 14 have stopping surfaces 18a, 18b facing each other and surrounding the recess 29, enclosing a working air gap 19. The configurations of the stopping surfaces 18a, 18b according to the invention shall be explained in further detail in the following figures.

[0023] If the magnet coil 15 is energized, the armature 14 moves in the direction of the magnet core 16 in order to close the working air gap 19, whereupon the stopping surfaces 18a, 18b of the magnet core 16 and of the armature 14 come into contact. The movement of the armature 14 brings about a relieving of the load on the valve tappet 5, so that the valve spring 12 presses the valve tappet 5 into the valve seat 7. The suction valve 2 closes. For the opening of the suction valve 2, the energizing of the magnet coil 15 is halted and the spring force of the armature spring 13 returns the armature 14 and the valve tappet 5 to the respective opened starting position of the suction valve 2.

[0024] The solenoid actuator 3, which is surrounded by an encapsulation 20 for electrical insulation and for sealing against the surroundings, is fixed in the actuator body 17 and the latter is fixed by a guide sleeve 21 on the pump cylinder head 1 of the high-pressure fuel pump. This fixation is done by a cap 22, which is placed on the guide sleeve 21 connected to the solenoid actuator 3 and joined by form fitting to the collar 9 of the pump cylinder head 1. The cap 22 for this purpose has an encircling detent lug 23, pointing radially inward and engaging with an annular groove 24 of the collar 9 arranged on the outer circumference. The guide sleeve 21 on which the cap 22 is placed has an encircling flange 25 arranged on the outer circumference for the bracing of the cap 22, whereby the guide sleeve 21 is furthermore braced against the collar 9. The flange 25 arranged so as to be is set back so that a portion of the guide sleeve 21 protrudes into the collar 9. This portion has an annular groove 26 on the outer circumference, in which a sealing element 27 is installed. The sealing element 27 lies under prestressing against the inner circumference of the collar 9, so that a sealing off of the low-pressure chamber 10 is accomplished in this way.

[0025] The guide sleeve 21 serves for the receiving and guiding of the armature 14. It is connected by a sleeve 28 to the magnet core 16 of the solenoid actuator 3. For this, the sleeve 28 is placed on the one hand on the guide sleeve 21, and on the other hand on the magnet core 16, and it is welded to the latter, for example. For the magnetic separation of the guide sleeve 21 from the magnet core 16, the sleeve 28 is made of a nonmagnetic material. The junction area lies inside the encapsulation 20.

[0026] FIG. 2 shows a detail view of the mutually facing stopping surfaces 18a, 18b of the magnet core 16 and the armature 14. The recess 29 receiving the armature spring 13 is made in the magnet core 16 and the armature 14, passing between them. Starting with the planar configuration of the stopping surfaces 18a, 18b as shown in FIG. 1, FIG. 2 shows a convex configuration 30 of both the magnet core 16 and the armature 14. The dimension B of the convex configuration 30 is preferably designed here such that no edge stress occurs at the stopping surfaces 18a, 18b in the event of a possible skewed position of the armature 14 relative to the magnet core 16 in the outer circumferential region of the mentioned components.

[0027] By contrast with this, in the configuration of FIG. 3 the stopping surface 18a of the magnet core 16 is formed so as to be planar, while the stopping surface 18b of the armature 14 has a toroidal configuration 31. The dimension B of the convex configuration 30 or the toroidal configuration 31 here lies preferably in the range of approximately 50 m to approximately 300 m.

[0028] FIG. 4 shows, by contrast with the embodiment of FIG. 3, a toroidal configuration 31 of both the magnet core 16 and the armature 14. Consequently, the stopping surfaces 18a, 18b of the armature 14 and the magnet core 16 has a convex/convex combination here.

[0029] In the embodiment of FIG. 5, the magnet core 16 again has a toroidal configuration 31 of the stopping surface 18a, while the stopping surface 18b of the armature 14 has a concave configuration 32 adapted to the toroidal configuration 31 (or vice versa). The degree of convexity or concavity may be the same or different. In particular, the degree of convexity may be less than the degree of concavity, so that it is ensured that no edge stress occurs even under unfavorable conditions with regard to a skewed position of the armature 14 with respect to the magnet core 16.

[0030] In conclusion, it is noted that any individual features described for the invention may be combined with each other and among each other.