Injector having an improved solenoid actuator

Abstract

An injector is described for injecting a fluid, in particular a fuel, comprising a solenoid actuator for operating a closing element, which releases and closes a through opening, the solenoid actuator including an armature which is connected to the closing element, an internal pole and an external magnetic circuit component, and the magnetic circuit component is a rolled magnetic sleeve made from a strip material.

Claims

1. An injector for an injection of a fluid, comprising: a closing element that releases and closes a through opening; and a solenoid actuator for operating the closing element, wherein: the solenoid actuator includes an armature connected to the closing element, an internal pole, and an external magnetic circuit component, and the magnetic circuit component is a magnetic sleeve rolled from a strip material, wherein: the rolled magnetic sleeve has a single layer and includes a first abutting edge and a second abutting edge that rest against each other in a rolled state of the magnetic sleeve, the solenoid actuator includes a bottom region disposed on an injector housing in a manner that projects as a ring and that is connected to the rolled magnetic sleeve at a second end of the magnetic sleeve disposed in the axial direction of the injector, the solenoid actuator includes a cover connected to the rolled magnetic sleeve at a first end of the magnetic sleeve situated in an axial direction, and the cover includes a slot that extends in the axial direction and is disposed at a recess of the rolled magnetic sleeve that is developed in a region of the first abutting edge and the second abutting edge, wherein a width in a circumferential direction of the slot corresponds to a width of the recess.

2. The injector as recited in claim 1, wherein the fluid is a fuel.

3. The injector as recited in claim 1, wherein: the first abutting edge has at least one projecting region, the second abutting edge has at least one recess, and the projecting region is disposed in the recess via a keyed connection in the rolled state of the magnetic sleeve.

4. The injector as recited in claim 3, wherein the projecting region has a constriction.

5. The injector as recited in claim 1, wherein the first abutting edge is connected to the second abutting edge via a welded joint.

6. The injector as recited in claim 1, wherein the recess is disposed at a first end in an axial direction of the injector.

7. The injector as recited in claim 6, wherein: the solenoid actuator includes electrical connection elements that are at least partially surrounded by a housing section, and the housing section is at least partially disposed in the recess.

8. The injector as recited in claim 1, wherein at least one of: a first welded joint is provided between the bottom region and the magnetic sleeve, and a second welded joint is provided between the cover and the magnetic sleeve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic, perspective view of an injector according to a first exemplary embodiment of the present invention.

(2) FIG. 2 shows a schematic view of the injector from FIG. 1 without an assembled magnetic circuit.

(3) FIG. 3 shows a schematic view of the injector from FIG. 1 with an assembled magnetic circuit.

(4) FIG. 4 shows a schematic view of a magnetic sleeve of a solenoid actuator according to a second exemplary embodiment of the present invention.

DETAILED DESCRIPTION

(5) In the following text, an injector 1 according to a first preferred exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 through 3. As may be gathered from the perspective overall view in FIG. 1, injector 1 includes a solenoid actuator 2 for operating a closing element 14, which is disposed at an end in axial direction X-X of injector 1. Closing element 14 is connected to an armature 21, which is able to be moved by solenoid actuator 2.

(6) In addition to armature 21, solenoid actuator 2 also includes an internal pole 22 (compare FIG. 2), a separating ring 26, and an external magnetic circuit component, which is provided in the form of a rolled magnetic sleeve 23.

(7) Rolled magnetic sleeve 23 is cylindrical and rolled from a rectangular strip material. The rolled magnetic sleeve has one layer and a first abutting edge 24 and a second abutting edge 25. The first and second abutting edges 24, 25 rest against each other in the rolled state of the magnetic sleeve.

(8) In order to simplify an assembly of the rolled magnetic sleeve and in particular to avoid a gap between the two abutting edges 24, 25, magnetic sleeve 23 has a projecting region 4 and a recess 5. As is able to be gathered from FIGS. 1 and 3, a keyed connection is provided between projecting region 4 and recess 5. Projecting region 4 of this exemplary embodiment has a semicircular shape and transitions to first abutting edge 24 by way of a straight neck region. In a geometrically corresponding manner, recess 5 is formed on second abutting edge 25 in order to allow for a keyed connection between projecting region 4 and recess 5.

(9) In addition, magnetic sleeve 23 includes a recess 3 in axial direction X-X. As may be gathered from FIG. 1, recess 3 is developed in the region of first and second abutting edges 24, 25.

(10) Furthermore, the magnetic circuit of solenoid actuator 2 includes two electrical connection elements 8 in the form of pins. Electrical connection elements 8 are partially extrusion-coated (see FIG. 3) with the aid of a housing section 9. Housing section 9 of electrical connection elements 8 is at least partially disposed in recess 3 in rolled magnetic sleeve 23. This makes it possible to achieve a particularly compact design.

(11) After solenoid actuator 2 has been assembled, a plug receptacle is also injection-molded onto electrical connection elements 8.

(12) In addition, solenoid actuator 2 includes a bottom region 27 and a cover 28. Cover 28 is situated at a first end of magnetic sleeve 23 disposed in axial direction X-X of the injector. Bottom region 27 is situated at a second end of magnetic sleeve 23 disposed in axial direction X-X. As may be gathered especially from FIG. 3, cover 28 includes a slot 29. Slot 29 has a width in the circumferential direction that corresponds to a width of recess 3 in magnetic sleeve 23. This makes it possible to achieve an uncomplicated accommodation of housing section 9 of electrical connection elements 8.

(13) Moreover, it is clear from FIGS. 1 and 3 that bottom region 27 is connected to magnetic sleeve 23 with the aid of a first welded joint 11. First welded joint 11 is provided along the circumference and surrounds it completely. Furthermore, cover 28 is connected by a second welded joint 12 to magnetic sleeve 23. Second welded joint 12 is also fully developed in the circumferential direction between cover 28 and magnetic sleeve 23.

(14) Closing element 14 is connected to armature 21 (see FIG. 2), and a restoring element 15 always resets closing element 14 to the neutral state in which solenoid actuator 2 is not actuated.

(15) According to the present invention, a rolled magnetic sleeve 23 may therefore be provided, which is able to be produced in a very cost-effective manner and be rolled from a rectangular strip material. A keyed connection, including projecting region 4 and a geometrically correspondingly developed recess 5, are provided in order to ensure a secure connection of the abutting edge regions of rolled magnetic sleeve 23. This simplifies in particular an assembly of solenoid actuator 2. The coil of solenoid actuator 2 may furthermore include a separate extrusion coat and be inserted into rolled magnetic sleeve 23; prior to assembling cover 28, an additional extrusion coat may be provided in the interior region between magnetic sleeve 23 and the coil in an effort to achieve better tightness. In a final step, cover 28 is then fixed in place on magnetic sleeve 23.

(16) FIG. 4 shows an alternative development of a keyed connection of an injector according to a second exemplary embodiment of the present invention. As may be gathered from FIG. 4, a constriction 6 is provided in the keyed connection between projecting region 4 and recess 5 at both abutting edges 24, 25. As a result, projecting region 4 has the shape of a puzzle piece, which makes it possible to achieve a particularly reliable keyed connection between the two free ends of rolled magnetic sleeve 23 in the circumferential direction.

(17) In addition, a welded joint is provided between first abutting edge 24 and second abutting edge 25, which includes a first welding point 16 and a second welding point 17 in this particular exemplary embodiment. The two welding points are provided at abutting edges 24, 25 at the ends disposed in the axial direction X-X in each case.

(18) As a result, an injector is able to be provided according to the present invention, which has a particularly cost-effective solenoid actuator. In a particularly preferred manner, the injector is used for the injection of fuel into a combustion engine.