GB2414602A

GB2414602A - Spring connector for electric motor

Info

Publication number: GB2414602A
Application number: GB0411723A
Authority: GB
Inventors: Ben To Fan Wong; Michael Y K Wong
Original assignee: Johnson Electric SA
Current assignee: Johnson Electric SA
Priority date: 2004-05-26
Filing date: 2004-05-26
Publication date: 2005-11-30
Also published as: GB0411723D0

Abstract

An electric motor is electrically connected to a PCB by a spring connector 24. The spring connector 24 has an aperture through which a terminal 18 or the motor extends, two locking fingers formed on the edge of the hole to grip the terminal and two arms having re-entrant end portions such that the re-entrant end portions bear against the terminal 18. The connector 24 is pressed into a hole 20 in the PCB such that the arms of the connector are resiliently deformed by the PCB. The hole 20 in the PCB has a conductive inner surface and the terminal 18 is connected to the PCB electrically by the connector 24 through the resilient contact made between the connector and the conductive surface, creating a solder free connection.

Description

24 1 4602 Connector for Electric Motor This invention relates to electric

motors and in particular, to a connector for connecting electric motors to a PCB.

Electric motors are usually connected to PCBs either by directly soldenug Be terminals to the PCB or by soldering lead wires from the motor to the PCB. Both arrangements provide very good electrical connection between the motor and Be PCB. However, they do require soldenog and both methods are time consuming.

ID Due to the lead content of the solder, alternate methods are being studied and iD certain cases, situations are required for solder tree connections on the basis of environmental health.

There is also a need for a sample and reliable method of connecting electric motors to aPCB.

Accordingly, the present invention comprises a cormector for connecting a pin type terminal of a miniature electric motor to a PCB, wherein the connector is a strip of conductive elastic material having a flat base portion and having at least one Ann extending substantially perpendicularly from the base portion, the base portion has an aperture for receiving a terminal and at least one locking finger resiliency deformed by insertion of the terminal to grip the terminal.

The invention also provides a method of correcting an electric motor to a PCB, including the steps of: preparing Me PCB with a through hole to receive the terminal, providing the hole with art inner conductive surface; placing a connector over the terminal by pressing Be terminal Bough an aperture in the connector including resiliently deforming a locking finger of the connector as the terminal is pressed through the aperture, placing the motor into position on the PCB with the terminal and connector aligned with the hole in the PCB by inserting tle terminal and connector into the hole and resiliently deforming the at least one arm of the connector by contact win the inner surface of the hole as the connector is pressed into the hole and causing the arm to make electrical contact with the conductive inner surface of the hole without soldering Preferred and optional Leases can be found in the dependent claims attached hereto.

One preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which; Figure 1 is a schematic sectional view of the connection between an electric motor and aPCB' I O Figures 2 and 3 are tiont and rear illustrations of an electric motor attached to a PCB, Figure 4 is art enlarged view of the correction illustrated in Figure 1; and Figure is an isometric view of a connector according to the present invention.

Figure I is sectional view of a connection between an electric motor 10 and a P(::B 12. A part of the motor 10 is show in schematic sectional fonn and Is illustrative of the connection between the PCB and Me motor.

Motor 10 may be a rnlniahlre stepping motor as used for exarnp}e, in an instrument panel where the motor is mounted on a PC board which provides lights, gauges, and other electronics and the motor drives an indicator for an analog type gauge.

The motor 10 and PCB 12 are more clearly shown in Figures 2 and 3 where Me complete motor is shown attached to the PCB. In Figure 2, the motor is viewed from above and the s}aflc and snaps can be seen protruding through the PCB. In Figure 3 is viewed from below The motor 10 has a housing which includes several (in this case, 3) snap fasteners 14.

Me motor also has an output shaft 16 which passes through the PCB to drive an indicator pointer. The motor 10 has a number of motor terminals 18 (in this embodiment, 4) which are connected to the PUB 12 for operating the motor in a stepping mode as required for an indicator. One seminal 18 is shown in Figure 1.

The terminal 18 is of the male type, extending Trough the 'motor housing and through a hole 20 in the PCB.

The connection is more clearly shown in Figure which is an enlarged sectional detail view of the connection. The hole 20 in the PCB is through plated to provide a conductive inner surface 22. The connection between the terminal 18 and the PCB is made by a connector 24 The connector 24 electrically cormects the terminal to the conductive inner surface 22 of the hole, which in tum, forms part of the conductive tracls for the PCB.

A connector 24 is shown in Figure 5. The connector is fanned from a strip of elastic conductive material such as beryllium copper or brass. The connector 24 has a base 26. An aperture 28 is formed in the base and two locking fingers 30 are formed on the edge of the aperture at diam.etncally opposed locations. Two arms 32 are bent out of the plane of the base, again at diametrically opposed locations. The arms 32 entered substantially perpendicularly to the base but may be slightly divergent. Each arm 32 has an end portion 34. The end portion has a first bend 36 which forms a chamfer- lile ramp portion to facilitate easy insertion of the connector 24 into the hole 20 of the PCB 12- Ihe end portion 34 has a second bend 38 which Oatcakes the end portion re entrant, i.e., to extend back towards the base. The end portion has a third bend 40 which extends the end of the arm back towards itself but Me arm ends before it does.

Thus, the arms fold back on themselves with We Bird bends facing each other across a small gap or touching each other.

The base also has two wing portions 42 which extend in the plane of the base on opposite sides along Me edges of Me base extending between Me alms.

In use, the connector 24 is located within the PCB hole with the anns 32 pressed against the conductive inner surface 22, making clectncal contact therebetween. The wings 42 prevent the connector from being pressed too far through the PCB. Me motor terminal 18 is pressed through the aperture 28 of the base, resiliently deflecting the lock fingers 30 in the process. The terminal 18 also separates the end portions of the arms by pressing against and being forced between the third bends. This is facilitated by the third bends where the end of the arms are formed into ramp surfaces or funnels to guide the insertion of the terminal between them. The third bends and the lock fingers formed electrical connections between the terminals and the connector. The lock fingers 30 being resiliently deflected, resiliently pressed onto the terminal 18. The end edge 44 of each lock finger is leR square cut of burred to bite into Me terminal I to prevent or resist separation.

The connectors thus electrically connect the motor terminals to Me conductive tracks of the PUB. The connectors do not provide a mechanical correction which is provided by the snaps 14. The connectors provide a {ass, reliable, relatively inexpensive and environmentally friendly, i.e., solder free, electrical connection between the motor and the PC8. Furthermore, the connector may be fitted to the motor and there inserted into Me PCE hole or the connector could be inserted into Me PCB hole first, and then the motor terminal inserted into Me connector. For certain applications requiring the connection to We PCB to be stronger or lower in resistance, it may be desirable to fit Me connector to Me PCB before the over components are dipped or wave soldered (using lead Dee solder, for examples and thus, make fast the connector with Me PCB.

The embodiment described above is given by way of example only and various modifications will be apparent to persons skilled me art without departing from the scope of the invention as defined in the appended claims.

Claims

Claims 1. A connector for connecting a pin type terminal of a miniature

electric motor to a PCB, wherein the connector is a strip of conductive elastic material having a flat base portion and having at least one anti extending substantially perpendicularly from the base portion, the base portion has an aperture for receiving a terminal and at least one locking finger resiliently deformed by insertion of e terminal to grip Me terminal
2. A connector according to claim 1, wherein the at least one locking finger is pressed from an edge of the aperture and has an edge which bites into the terminal to prevent removal.
3. A connector according to claim 1 or claim 2, wherein there are two fingers arranged to bear on the terminal at diametrically opposed sides thereof
4. A connector according to any one of the preceding claims, wherein die am has an end portion which is adapted to assist insertion of me terminal To a hole in We PCB.
5. A connector according to claim 4, wherein Me end portion is re-entrant.
6. A corrector according to claim S. wherein the re-entrant portion is finther bent inwardly to bear against the terminal At a point spaced from the end of Me ann.
7. A connector according to any one of Me preceding claims, wherein there are To anns at diametrically opposed location.
8. A connector according to any one of the preceding claims, wherein the connector is arranged to make electrical contact USA the PCB bar being pressed into a hole in PCB which has a conductive inner surface, the substantially perpendicular portions of Me or each arm being resiliently pressed against Me conductive surface.
9. A connector according to any one of the preceding claims, wherein the or each arm is resiliently pressed into contact with the conductive surface of the hole in the PCE, by resilient deformation of the reentrant arm portion being squeezed between Me terminal and the inner surface of the hole.
10. method of electrically connects a terminal of an electric motor to a PCB, including the steps of: preparing the PCB with a through hole to receive the terminal; providing the hole with an inner conductive surface; placing a connector over the terminal by pressing the terminal Trough an aperture ire We connector including resiliently deforming a locking finger of the connector as the terminal is pressed tluougb the aperture; placing the motor into position on the PCB with the terminal and connector aligned with the hole in me P(:B by inserting the terminal and connector into the hole and resiliently deforming Me at least one am1 of the connector by contact win the inner surface calf the hole as the cormector is pressed into the hole and causing the arm to malce electrical contact with the conductive inner surface of the bole without soldering.
11. The method of claLm I O irclud forming a re-entrant end portion on the at least one ann to assist insertion of the connector into the hole.
12. The method of c1aLm 11 including Per bending the re-entrant end portion and pressing the end portion against the terminal as Me arm is resiliently deformed by pressing the terminal and connector into the hole.
13. Me method oF claim 1O7 11 or 12 including shaping Me hole in the PCB to accommodate the connector.
14. The method of claim lO or 11 including placing the connector in the hole before Be motor is fixed to the PCB and the terming is pressed into the connector.
15. The method of claim IO, 11 or 12 including fitting the connector to the terminal before Me connector is pressed into We hole.
16. A method of electrically connecting a terminal of an electric motor to a PCB substantially as hereinbeforc described win reference to the accompanying drawings
17. A connector for connecting an electric motor to a PCB substantially as hereinbefore descnbed with reference to the accompanying drawings.