A control interface device for an electric motor and method of manufacturing the same

Abstract: The control interface device (1) for an electric motor (M), particularly an electric motor (M) for operating servomechanisms on a vehicle, comprises a conductor frame (2), an active integrated component (4) mounted on the conductor frame (2), and a plurality of electric connectors (5,6). A single insulating, one-piece enclosing body (9) contains the conductor frame (2) with the active integrated component (4) and the electric connectors (5,6) included to the conductor frame (2). Thus, all of the elements required for powering and controlling the motor (M) are gathered inside a single enclosing body (9) which is convenient to handle and connect.

Description: This invention relates to a control interface device for an electrical load and to a method of manufacturing the same. The field of application of this invention is particularly, but not solely, related to an electric motor for operating such servomechanisms as may equip a vehicle, and reference to that field will be made in the following description for convenience of illustration. Electric motors are utilized in ever increasing number on modern vehicles for operating a range of servomechanisms, such as window regulators, power seats, heating/air-conditioning system controls, self-locking doors, aerial drives, etc. Such motors must be powered under control by some specific electric and electronic components of a passive type (resistors and capacitors) as well as an active type (an integrated circuit). To this aim, a printed circuit is usually provided to carry the necessary passive and active components. The printed circuit is first mounted onto an insulating holder, and then connected electrically to the motor by fitting purposely provided female connectors thereof over projecting leads from the motor. The female connectors are simple throughgoing holes formed in the printed circuit board which may be provided with deformable lugs for retaining the leads securely therein after their insertion. In addition, a multiple connector is to be attached to the printed circuit for connection to its associated power and control wiring. Accordingly, the assembling operation to the motor tends to be an awkward one. Control interface devices for various purposes are know in the art. For example, EP-A-0252481 discloses a connector 43 embodying electrical connections for controlling a motor in a vehicle; DE-U-8527350, US-A-3500085 and DE-A-1220042 disclose electrical connecting elements for electric motors. The underlying problem of this invention is, therefore, to provide for simpler assembly to a vehicle electric motor. This problem is solved, according to the invention, by a method of manufacturing according to claim 1 and by a control interface device according to claim 2. In this way, all of the required elements for powering and controlling the motor can be contained within a single enclosing body which is more convenient to handle and connect. The electric connectors normally comprise male connectors for connection to power and control wires, and female connectors for connection to the motor; accordingly, the enclosing body will preferably include alignment pins formed integrally at locations proximate to the male connectors. The alignment pins function to ensure a correct and secure mechanical coupling to the power and control wires. Preferably, the enclosing body is injection molded around the conductor frame with the active component. Further features and advantages of a control interface device according to the invention will become more clearly apparent from the following description of a preferred embodiment thereof, to be read in conjunction with the accompanying drawings. In the drawings: Figure 1 is a perspective view showing schematically a device according to the invention as applied to an electric motor; and Figures 2 and 3 are perspective views illustrating schematically sequential steps in the process of making the device depicted in Figure 1. Shown generally at 1 in the drawing figures is a control interface device for an electric motor M. The device 1 comprises a conductor frame 2 on which passive electric components, such as a capacitor 3, and an active electric component or integrated circuit 4 are mounted; specifically, the integrated circuit 4 is mounted in a dedicated central area 4a of the conductor frame 2. The conductor frame 2 includes both points of connection for the above-mentioned electric components and connectors for connection to the outside world. In particular, the frame 2 includes female connectors 5 for connection to the motor M and the passive components, and male connectors 6 for connection to power and control wires 7. Further, at a first stage of the method of manufacturing the device 1, the conductor frame 2 also has waste portions 8 useful to hold together the various portions of the frame 2. The conductor frame 2 with the integrated circuit 4 is contained within an enclosing body 9 which is a one-piece construction injection molded from an electrically insulative material. The female connectors 5 can be reached through throughgoing holes 10 which penetrate the enclosing body 9. The male connectors 6 are allowed to project from the enclosing body 9, which body is provided with alignment pins 11 formed integrally therewith at locations proximate to the male connectors 6. The device 1 is manufactured as follows. During a first step, the frame 2 is formed from a sheet of a conductive material; the frame 2 also includes the waste portions 8, as required to impart a degree of stiffness to the conductor frame 2. During a second step, the integrated circuit 4 is secured in the area 4a of the conductor frame 2 and its electric links are established. The electric links are intended to interconnect the integrated circuit 4 and the connectors 5 and 6. During a third step, the enclosing body 9 (complete with the alignment pins 11) is molded over the conductor frame 2 by an injection molding process from a suitable electrically insulative plastics material. During a fourth step, the waste portions 8 of the conductor frame 2 are removed, as presently no longer required owing to the presence of the enclosing body 9. Finally, the passive components, such as the capacitor 3, are secured and connected electrically by fitting the respective leads into the female connectors 5. The interface device 1 is now ready to be installed on the motor M. This is simply done by inserting the motor M leads into the respective female connectors 5 on the device 1. Connection to the power and control lines from the vehicle electric system is even simpler to carry out by just fitting respective female connectors of said lines over the male connectors 6. The alignment pins 11 will foster correct insertion and provide for the necessary mechanical securement. As may be appreciated, a device according to the invention can solve the technical problem proposed at the outset of this description, and provide for more straightforward assembling of electric motors to a vehicle. Additionally thereto, the invention affords a significant reduction in both assembly (on account, indeed, of the simpler procedure provided thereby) and material costs; in fact, the device of this invention is less expensive than the whole of the conventional devices which it is designed to replace.

Claims: Method of manufacturing a control interface device for an electrical load, particularly an electric motor for operating servomechanisms on a vehicle, characterized by comprising the following steps: forming a frame (2) from a sheet of a conductive material, the frame (2) including: a central area (4a) for receiving an active integrated component (4), first connectors (5) for connection to the electrical load (M), second connectors (6) for connections to power and control wires (7), and a waste portion (8) surrounding the central area (4a) and the connectors (5, 6), for keeping them together, securing the active integrated component (4) to the central area (4a) of the frame (2), connecting active integrated component (4) to the connectors (5, 6), molding an enclosing body (9) of electrically insulative material over the frame (2), including alignment pins (11) formed integrally therewith at locations proximate to the second connectors (6), said body (9) enclosing the active integrated component (4) and the central area (4a) of the frame (2) and leaving the connectors (5, 6) the waste portion (8), and the alignment pins (11) exposed, removing the waste portion (8). Control interface device for an electrical load manufactured according to the method of claim 1, particularly for an electric motor for operating servomechanisms on a vehicle, comprising: a conductor frame (2), an active integrated component (4) mounted on the conductor frame (2), a plurality of electromechanical connectors (5, 6) made solid with the conductor frame (2), a single insulating enclosing body (9), being a one-piece construction and containing the conductor frame (2) , with the active integrated component (4), characterized by alignment pins (11) being formed integrally with the enclosing body (9).

Inventors: COGNETTI CARLO, MARCHISI GIUSEPPE, COGNETTI, CARLO, MARCHISI, GIUSEPPE
Applicants: SGS THOMSON MICROELECTRONICS, SGS-THOMSON MICROELECTRONICS S.R.L.
Application year: 1993
Main classification: H02K23
IPC codes: H02K5, H02K23, H02K11