Injector, injection-molding tool, and method for manufacturing an injector

Abstract

An injector for introducing a fluid includes a main body designed as an insert and including a first tool contact surface for an injection-molding tool and a second tool contact surface for the injection-molding tool; and an injection-molded housing that completely encloses the main body on at least one portion of the main body, the injection-molded housing including at least one first opening that extends linearly towards the main body.

Claims

1. An injector for introducing a fluid, the injector comprising: a main body that includes a first tool contact surface for an injection-molding tool and a second tool contact surface for the injection-molding tool; and an injection-molded housing that encloses at least a portion of the main body and that includes a first opening that extends linearly towards the main body, wherein the injection-molded housing includes a second opening that extends linearly towards the main body of the injector, wherein the first opening and the second opening are situated at an angle of 90° relative to each other, wherein the first opening and the second opening are situated offset in relation to each other in a direction of a center axis of the injector.

2. The injector of claim 1, wherein the first opening extends up to the main body.

3. The injector of claim 2, further comprising an injection-molded material skin (a) in which there is a linear slot that is parallel to the center axis of the injector and (b) that is positioned on an end of the first opening closest to the main body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic view of an injector according to an example embodiment of the present invention.

(2) FIG. 2 shows a schematic perspective view of the injector of FIG. 1 from a first direction, according to an example embodiment of the present invention.

(3) FIG. 3 shows a schematic perspective view of the injector of FIG. 1 from a second direction, according to an example embodiment of the present invention.

(4) FIG. 4 shows a schematic sectional view of an injection-molding tool in a closed state, according to an example embodiment of the present invention.

(5) FIG. 5 shows a schematic detailed view of a support pin of the injection-molding tool of FIG. 4, according to an example embodiment of the present invention.

(6) FIG. 6 shows a schematic side view of an injector according to another example embodiment of the present invention.

DETAILED DESCRIPTION

(7) Example embodiments of the present invention, are directed to an injector 1, an injection-molding tool, and a manufacturing method for the injector. FIG. 1 schematically shows a side view of an example injector 1, which is, for example, a fuel injector for injecting liquid fuel.

(8) Injector 1 includes a main body 2, which includes a metallic valve housing, in which an actuator, for example, a magnetic actuator, and a closing element, for example, a valve needle or the like, are situated. The injector injects fuel, for example, directly into a combustion chamber at end 8 of the injector opposite to a fuel connection 7.

(9) In addition to main body 2, injector 1 includes an injection-molded housing 3. Injection-molded housing 3 is preferably manufactured from a plastic material. Injection-molded housing 3 furthermore preferably includes an electrical plug connection 6, via which a power supply and control of injector 1 take place.

(10) A first opening 4, which is cylindrical in this example embodiment, is provided in injection-molded housing 3. First opening 4 extends completely through injection-molded housing 3 up to the outer jacket of main body 2. As is apparent from FIG. 1, first opening 4 is perpendicular to a center axis X-X of the injector.

(11) As is apparent from FIGS. 2 and 3, injection-molded housing 3 completely encloses a middle part of main body 2 in the circumferential direction of the main body.

(12) Furthermore, a first tool contact surface 21 and a second tool contact surface 22 are provided on main body 2 of the injector. As is apparent from FIG. 1, first and second tool contact surfaces 21, 22 delimit the expansion of injection-molded housing 3 in axial direction X-X. An injection-molding tool 30, which is described hereafter with reference to FIGS. 4 and 5, rests against the two tool contact surfaces.

(13) As is apparent from FIG. 4, injection-molding tool 30 includes a first tool half 31 and a second tool half 32. An inflow opening 33, via which the injection-molding material is injected into a cavity 35, which results upon the assembly of first and second tool half 31, 32, is provided in second tool half 32. This is indicated by arrows A in FIG. 4.

(14) A cylindrical support pin 34, which protrudes into cavity 35, is provided in first tool half 31. As is apparent from FIG. 4, support pin 34 is used to support main body 2, which is inserted as an insert into injection-molding tool 30, in order to produce injection-molded housing 3 by injection-molding. First and second tool halves 31, 32 form a seal on first and second tool contact surfaces 21, 22, as schematically shown in FIG. 4.

(15) Main body 2, designed as an insert, includes a cylindrical shape in the area of support pin 34. In this way, a free end 34a, which is a planar surface, rests linearly against main body 2. After the injection molding and removal of the two tool halves 31, 32, first opening 4 shown in FIGS. 1 and 2 is thus formed by support pin 34. Because of the linear contact during the injection-molding procedure between support pin 34 and main body 2, a plastic skin results at the end of first opening 4, which includes a slotted opening in axial direction X-X of main body 2.

(16) As is apparent from FIG. 4, support pin 34 is used during the injection-molding procedure to support main body 2 against the injection pressure, which arises due to the injection of the injection-molding material into cavity 35. As is furthermore apparent from FIG. 4, support pin 34 is situated directly opposite to inflow opening 33 for this purpose. In this way, an optimal support of the insert can be achieved. A diameter of cylindrical support pin 34 is preferably equal to a diameter of inflow opening 33.

(17) A gating point 9, which is located on the outer circumference of injection-molded housing 3, is schematically indicated in FIG. 3.

(18) According to an example embodiment of the present invention, a method for manufacturing injector 1 can therefore be carried out very easily and cost-effectively using injection-molding tool 30, and in particular bending of main body 2 of the injector, which is designed as an insert, can be avoided. The following are three alternatives that are possible for this purpose. On the one hand, as described, support pin 34 can contact main body 2 in injection-molding tool 30, as shown in FIG. 4. According to an alternative, there can also be no contact between support pin 34 and inserted main body 2, but rather a very small distance, preferably less than 0.5 mm, particularly preferably less than or equal to 0.1 mm, so that a minimum deflection of the main body during the injection procedure is enabled. This minimal bending does not damage main body 2, however. As another alternative, a pre-tension and thus a deflection of main body 2 against the injection direction through inflow opening 33 can also be enabled by a contact of support pin 34 with inserted main body 2. This deflection against the injection direction can be compensated for by the high pressure during the injection of the injection-molding material, so that an injector having injection-molded housing 3 can be manufactured, which does not have a deflection on main body 2 as a final product.

(19) FIG. 6 shows an injector 1 according to another example embodiment of the present invention. Injector 1 of this example embodiment essentially corresponds to the first example embodiment, a second opening 5 also being provided in injection-molded housing 3 in addition to first opening 4 in injection-molded housing 3. As is apparent from FIG. 6, first and second openings 4, 5 are situated at an angle of 90° relative to each other in injection-molded housing 3. A first center axis of first opening 4 is identified with reference numeral M1 in FIG. 6 and a second center axis M2 of second opening 5 is perpendicular thereto. Both center axes M1, M2 are in turn perpendicular relative to center axis X-X of injector 1.

(20) As is furthermore apparent from FIG. 6, first opening 4 and second opening 5 are situated offset in relation to each other by a distance Y in the direction of center axis X-X of the injector. A gating point 9 is situated between first opening 4 and second opening 5 in axial direction X-X of the injector. As explained in the first example embodiment, first opening 4 and second opening 5 are produced by two support pins, which are provided in the injection-molding tool. An improved support of inserted main body 2 in the injection-molding tool can be achieved by the provision of two support pins, in particular also against a melt pressure that acts on inserted main body 2 during and after the injection procedure. The second support pin is schematically shown by dashed lines with reference numeral 34′ in FIG. 4.