Electromagnetic actuator with molded connector

Abstract: A method of joining a connector 12 to an electromagnetic actuator 10 is provided. The actuator 10 has a metal housing structure 14, 18 and electrical leads 24, 26 extending from the housing structure. The method includes providing at least one channel 30 in the housing structure and a port 36 communicating with the at least one channel 30 and with a mounting surface 28 of the housing structure. The plastic connector 12 is molded on the mounting surface 28 and plastic material in fluid form is permitted to flow through the port 36 and into the at least one channel 30 to fill the channel and the port. The plastic material is permitted to cool and harden to define the connector 12 with the connector being interlocked with respect to the housing structure via the plastic material in the at least one channel 30.

Description: FIELD OF THE INVENTION This invention relates to an electromagnetic actuator for a vehicle engine and, more particularly, to an electromagnetic actuator having a molded connector providing a connection for electrical energy to the actuator. BACKGROUND OF THE INVENTION A conventional electromagnetic actuator for opening and closing a valve of an internal combustion engine generally includes "open" and "close" electromagnets which, when energized, produce an electromagnetic force on an armature. The armature is biased by a pair of identical springs arranged in parallel. The armature is coupled with a gas exchange valve of the engine. The armature rests approximately half-way between the open and close electromagnets when the springs are in equilibrium. When the armature is held by a magnetic force in either the closed or opened position (at rest against the open or close electromagnet), potential energy is stored by the springs. If the magnetic force is shut off with the armature in the opened position, the spring's potential energy will be converted to kinetic energy of the moving mass and cause the armature to move towards the close electromagnet. If friction is sufficiently low, the armature can then be caught in the closed position by applying current to the close electromagnet. Typically, providing a connection for electrical energy to the actuator is accomplished by using a plastic connector joined directly to a surface of the metal actuator by a high pressure overmolding process. However, this connection is not robust since it is difficult to create a strong joint between the plastic connector and the flat metal surface of the actuator. Accordingly, a need exists to join a plastic connector to a surface of a metal actuator such that a robust connection is created between the metal actuator and plastic connector. SUMMARY OF THE INVENTION An object of the present invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is obtained by providing a method of joining a connector to an electromagnetic actuator. The actuator has a metal housing structure and electrical leads extending from the housing structure. The method includes providing at least one channel in the housing structure and a port communicating with the at least one channel and with a mounting surface of the housing structure. The plastic connector is molded on the mounting surface and plastic material in fluid form is permitted to flow through the port and into the at least one channel to fill the channel and the port. The plastic material is permitted to cool and harden to define the connector with the connector being interlocked with respect to the housing structure via the plastic material in the at least one channel. In accordance with another aspect of the invention, an electromagnetic actuator is provided and includes housing structure having a mounting surface and at least one channel therein generally adjacent to the mounting surface. An upper electromagnet and a lower electromagnet are provided in the housing structure and are disposed in spaced relation. Each of the upper and lower electromagnets has electrical leads. An armature is mounted for movement between the upper and lower electromagnets. A connector is joined with the mounting surface and has a portion extending into the at least one channel so as to interlock the connector with the housing structure. The connector also covers at least a portion of the leads. Other objects, features and characteristic of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a perspective view of an electromagnetic actuator having a plastic electrical connector provided in accordance with the principles of the preset invention; FIG. 2 is an exploded view of the electromagnetic actuator of FIG. 1; FIG. 3 is an enlarged cross-sectional view of the connector-actuator joint of the electromagnetic actuator of FIG. 1; and FIG. 4 is an enlarged cross-sectional view of a second embodiment of a connector-actuator joint of the electromagnetic actuator of the invention. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, a perspective view of an electromagnetic actuator is shown, generally indicated 10, including an electrical connector 12 provided in accordance with the principles of the present invention. The electromagnetic actuator 10 comprises housing structure including an upper housing 14 containing an upper electromagnet 16 therein and a lower housing 18 containing a lower electromagnet 20. An armature 22 is arranged for movement between the electromagnets 16 and 20. The upper and lower housings are preferably made of aluminum or other metals. The armature 22 is associated with shaft structure (not shown) which may be coupled to a gas exchange valve of a vehicle engine. In the typical manner, a pair of opposing springs (not shown) are associated with the armature 22 to move the armature between the upper and lower electromagnets. The upper electromagnet 16 is powered at leads 24 and the lower electromagnet 20 is powered at leads 26. In accordance with the principles of the present invention, a plastic connector 12 is molded over the upper surfaces of the leads 24 and 26 and is joined to the upper housing 14 and lower housing 18 of the actuator 10. The plastic material is preferably glass-filled nylon or other similar plastic material. In order to ensure a robust joint between the flat metallic mounting surface 28 (FIG 3) of the housing structure, at least one plastic receiving channel 30 is defined in the upper housing 14 generally adjacent to a mounting surface 28. The mounting surface 28 is defined by cooperating planar surfaces 28' ; and 28" of the upper and lower housing, respectively. In the illustrated embodiment, two channels 30 are provided in the upper housing 14 in spaced relation, as best shown by the dashed lines in FIG. 2. With reference to FIGS. 2 and 3, each of the channels 30 communicates with a recess 32 defined in upwardly facing surface 34 of the lower housing 18, the function of which will become apparent below. At least one fill port 36 is provided in the mounting surface 28 to communicate with each channel 30 such that during molding of the connector 12, plastic material in fluid form may flow through the fill port and fill the associated channel 30. The port 36 is disposed generally transverse with respect to the associated channel 30. In the illustrated embodiment, a plurality of fill ports 36 are associated with each channel 30. Although continuous, elongated, vertically extending channels 30 are shown in FIGS. 2 and 3, with reference to FIG. 4, it can be appreciated that the channels 30' may be an extension of each fill port 36 and each channel need not be in communication with another channel 30'. In FIG. 4, like reference numerals with respect to FIG. 3 indicate like parts of the invention. It is preferable to cast the upper and lower housings, and during the casting process, to define the channels and recesses with negative draft. During the molding process for creating the connector 12, a mold is provided to define the connector 12 and molten plastic is directed to the mold. Plastic flows into the fill ports and fills the channels 30 and the recesses 36 and the fill ports 36. Once the plastic is allowed to cool, the plastic material in the recesses 36 and channels 30 interlocks the connector 12 with the upper housing 14 and with the lower housing 18. FIG. 3 shows the plastic material in the recess 32 and channel 30. FIG. 2 shows the connector 12 in an exploded view, with the plastic material indicated at 40 being the material which fills the channels 30. The connector 12 includes a pair of gussets 42 extending from a body portion 44 thereof. The body includes an opening 46 (FIG. 3) so as to gain access to the underside of each lead 24 and 26 to provide power to the actuator 10 by pressure contact with a cable rail (not shown) mounted on the cylinder head of an engine. The gussets 42 provide support for loads exerted on the connector 12 which may be caused by the cable rail pressure contact with the leads 24 and 26, by thermal expansion, by vibration, etc. As shown, each gusset 42 is disposed generally adjacent to a channel 30 so that sufficient plastic material is provided to make the housing structure-connector joint robust It can be appreciated that the connector 12 of the invention is joined securely to the actuator 10 due to the channels 30 and recesses 32 in the housing structure, is easy to manufacture, and has low manufacturing costs. The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed by the scope of the following claims.

Claims: An electromagnetic actuator (10) comprising: a metall housing structure (14,18) having a mounting surface (28) and at least one channel (30) therein generally adjacent to said mounting surface (28), an upper electromagnet (16) and a lower electromagnet (20) in said housing structure (14,18) and disposed in spaced relation, each of said upper and lower electromagnets having electrical leads (24,26), an armature (22) mounted for movement between said upper and lower electromagnets, and a plastic connector (12) joined with said mounting surface (28) and having a portion extending into said at least one channel (30) so as to interlock said connector (12) with said housing structure (14,18), said connector (12) covering at least a portion of said leads (24,26). The actuator according to claim 1, wherein said connector is composed of plastic material. The actuator according to claim 2, further including a port in said mounting surface and in communication with said at least one channel such that during a process of molding said connector, said plastic material may enter said port and fill said channel and said port. The actuator according to claim 3, wherein said channel is elongated and said port is generally transverse with respect to said at least one channel. The actuator according to claim 4, wherein a plurality of ports are defined in said mounting surface and in communication with said at least one channel. The actuator according to claim 2, wherein said plastic material is glass-filled nylon. The actuator according to claim 2, wherein said housing structure is composed of metal. The actuator according to claim 7, wherein said metal is aluminum. The actuator according to claim 1, wherein said connector includes a main body and a pair of gussets extending from said main body, said gussets being in spaced relation. The actuator according to claim 9, wherein two channels are defined in said housing structure, each channel being generally adjacent to an associated gusset and wherein at least one port is defined in said mounting surface and in communication with an associated channel, material of said connector extending into and filling said channels and said ports. The actuator according to claim 1, wherein said leads have an upper surface and a lower surface, said connector being over-molded on said upper surface of each of said leads. The actuator according to claim 11, wherein said connector has an opening so as to access said lower surface of each of said leads. The actuator according to claim 1, wherein said housing structure comprises an upper housing and a lower housing each having a generally planar surface, said planar surfaces cooperating to define said mounting surface, said at least one channel being defined in said upper housing, said lower housing including a recess therein which communicates with said at least one channel. A method of joining a connector (12) to an electromagnetic actuator (10), the actuator having a metal housing structure (14,18) and electrical leads (24,26) extending from the housing structure (14,18), the method including: providing at least one channel (30) in said housing structure (14,18) and a port (36) communicating with said at least one channel (30) and with a mounting surface (28) of said housing structure, molding a plastic connector (12) about the leads (24,26) and on said mounting surface (28) and permitting plastic material in fluid form to flow through said port (36) and into said at least one channel (30) to fill said at least one channel (30) and said port (36), and permitting said plastic to cool and harden to define said connector (12) with said connector (12) being interlocked with respect to said housing structure (14,18) via the plastic material in said at least one channel (30). The method according to claim 14, wherein two channels are provided in said housing, each said channel having a port communicating therewith, the method including permitting said plastic material to flow through each said port and into an associated channel. The method according to claim 14, wherein said housing structure is casted and said channel is provided in said housing structure so as to have negative draft. The method according to claim 14, wherein the molding step includes molding glass-filled nylon. The method according to claim 14, wherein the molding step includes molding plastic material onto one surface of said leads. The method according to claim 18, wherein the molding step includes providing an opening in the connector so as to gain access to a surface of said leads opposite said one surface. The method according to claim 15, wherein the molding step includes defining the connector to have a body and a pair of gussets extending from said body, said gussets being generally adjacent to said channels.

Inventors: BULGATZ DENNIS, MCFARLAND ROBERT, BULGATZ, DENNIS, MCFARLAND, ROBERT
Applicants: SIEMENS VDO AUTOMOTIVE CORP, SIEMENS VDO AUTOMOTIVE CORPORATION
Application year: 1999
Main classification: H01F7
IPC codes: H01R13, H01F27, H01F7, F01L9