GB2345585A

GB2345585A - Releasable splashproof cover for a miniature electric motor

Info

Publication number: GB2345585A
Application number: GB9900184A
Authority: GB
Inventors: Dennis Man Fat Wong
Original assignee: Johnson Electric SA
Current assignee: Johnson Electric SA
Priority date: 1999-01-07
Filing date: 1999-01-07
Publication date: 2000-07-12
Also published as: GB9900184D0

Abstract

A cover 10 for an electric motor has two conductors 40 fitted to an insulating body 20. The conductors 40 have male terminals 42 which are disposed in a socket 24 formed in the insulating body for connecting to an appliance plug and female terminals 44 for connecting to male motor terminals. A noise suppression device 60 such as a surge suppressor is connected between the conductors. The body 20 has a snap fit feature to releasably secure the cover to the motor. The snap fit feature comprises two resiliently deformable fingers 36 each having a locking projection 38 arranged to engage a hole in a respective motor terminal when the cover is correctly fitted and thereby prevent removal of the cover until the fingers are deflected, removing the locking projections from the holes in the motor terminals and releasing the cover.

Description

Cover For An Electric Motor Background of the Invention The present invention relates to a cover for an electric motor and in particular, to a releasable cover for a miniature permanent magnet direct current motor.

Covers are known for miniature electric motors. See, for example, UK patent specification GB 2225672 and EP 0655822-A1, where a cover for a miniature pmdc motor is provided to protect the motor from splashes in an automotive application.

A disadvantage of such covers is that they cannot be released. Once they are fitted to the motor, they cannot be removed without causing damage to the motor and/or cover.

However, the covers also provide an easy method to provide customised connections to an appliance without modifying the motor and in particular, the terminal arrangement of the motor.

Accordingly, there is a need for providing a cover for an electric motor which is releasably connectable to the motor and having terminal connections for mating with and electrically connecting the motor terminals to a connector of an appliance to which it is fitted. Thus, in one aspect thereof the present invention provides a cover for an electric motor having an end cap with motor terminals, the cover comprising: a body of plastics material having a base portion adapted to sit on the end cap, a connector portion adapted to receive an electrical appliance plug and a locking portion adapted to releasably fix the cover to the end cap; and conductor means arranged to engage the motor terminals and adapted to form connector terminals within the connector portion of the body.

Preferably, the locking portion includes two resiliently deformable fingers formed integrally with the cover body, each finger being arranged to be resiliently deformed by insertion of a protruding male type motor terminal into the cover and having a locking projection engageable with a hole in the motor terminal when the motor terminal is fully inserted thereby preventing removal of the cover.

Preferably each finger has an extension accessible from externally of the cover to permit manual deflection of the finger to disengage the locking projections from the holes in the motor terminals thereby releasing the motor terminals and allowing the cover to be removed.

The cover, in certain embodiments, may house one or more noise suppression devices such as surge suppressors, capacitors and chokes.

Brief Description of the Drawings 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 plan view of the preferred cover; Figure 2 is an underside plan view of the cover ; Figure 3 is a side view of the cover sectioned along line III-III of Figure 1; Figure 4 is an enlarged side view of a part of a conductor of the cover of Figure 1; and Figure 5 is a sectional end view of the conductor of Figure 4.

Detailed Description of the Preferred Embodiment As can be seen from the drawings, the cover comprises the following components: a body 20, two conductors 40 and a noise suppression component 60 as shown in Figures 1 to 3. In Figure 3, a motor 12 with its motor terminals 14 and bearing boss 16 are shown in phantom to illustrate the connection between the cover and a motor to which it is fitted.

The body 20 is a plastics material part having a base 22 which sits on the end cap of the motor 12 and a connector portion 24 in the form of a socket to receive and where desirable, interlock with an appliance plug for supplying power to the motor. On the under side of the base 22 is a circular recess 26 arranged to receive a bearing boss 16 of an end cap of the motor.

The two conductors 40 are made identical for ease of manufacturing. One conductor is shown enlarged in Figures 4 and 5. Each conductor 40 has a male terminal 42 and a female terminal 44. The male terminal 42 extends through holes in the base 22 and into the socket formed by the connector portion 24 of the body to mate with terminals of an appliance plug when fitted. To prevent withdrawal of the conductor, the male terminals 44 have a stepped shoulder 46 which is swaged at 48 or otherwise deformed within the socket. The stepped shoulder 46 also sets the length that the terminal can be inserted through the hole in the base.

The female terminal 44 is C-shaped, defining a passageway for receiving and gripping a protruding male motor terminal 14 of the end cap. The female terminal 44 is disposed in a recess 28 in the base 22 and located so as to be aligned with the male motor terminal 14. The male and female terminals 42,44 of the conductor are connected together by a connecting portion 50. The stepped shoulder 46 has a lateral extension or arm 52 extending from the base of the shoulder adjacent the connecting portion 50.

This arm 52 has a mechanical connection type terminal 54 in the form of two fingers 56 which are arranged to straddle and grip a lead 62 from the noise suppression component 60.

The noise suppression component 60 is a bi-directional diode or surge suppressor which limits maximum voltage drop across the conductors. The surge suppressor 60 has two leads 62 connected to respective conductors 40 by way of the mechanical connection terminals 54 as previously described. The surge suppressor 60 is received in a recess 30 in the base of the cover with the leads 62 lying in channels 32 extending from the recess 30. The leads 62 are held in place by the mechanical connection terminals 54 while the surge suppressor 60 is held in the recess 30 by one of the connecting portions 50.

The body 20 has two depending spigots 34 of differing shape which are used to key the cover to the motor and are received in correspondingly shaped recesses in the end cap to prevent the cover from being fitted to the end cap in the wrong orientation.

To latch the cover to the motor, to prevent accidental separation or removal of the cover, the cover has a resilient finger 36 associated with each female terminal recess 28. Each finger 36 has a barb or locking projection 38 which is arranged to engage a hole in the motor terminals 14. As a motor terminal is pressed into a female terminal 44, the motor terminal presses against the locking projection 38 causing the finger 36 to resiliently bend or deflect, allowing the terminal to push the projection out of the way. At the fully inserted position, the locking projection 38 is pressed into a hole in the motor terminal by the resilient urgings of the finger 36, preventing the motor terminal 14 from being withdrawn. To withdraw the motor terminal, it is first necessary to manually deflect the finger 36 thereby withdrawing the locking projection 38 from the hole in the motor terminal, releasing the motor terminal and allowing the cover to be removed. The female terminal recess 28 has a through-hole 29 which allows access to the finger 36 or through which the finger 36 extends, for manual deflection of the finger by a user.

Thus it can be seen that the cover provides a very simple solution to adapting the motor terminals of a motor to suit the requirements of an appliance plug while allowing the motor to be replaced for whatever reason without requiring the cover to be replaced with the motor, thereby allowing the motor to be used with an industry standard plug connector.

Various modifications will be apparent to those skilled in the art and it is intended to cover all such variations as fall within the scope of the invention as defined by the appended claims. In particular, the noise suppression component may be a capacitor connected between the conductors or may include inductors or chokes forming a part of the conductor portion electrically connecting the female terminal and the male terminal of a single conductor.

Claims

1. A cover for an electric motor having an end cap with motor terminals, the cover comprising : a body of plastics material having a base portion adapted to sit on the end cap, a connector portion adapted to receive an electrical appliance plug and a locking portion adapted to releasably fix the cover to the end cap; and conductor means arranged to engage the motor terminals and adapted to form connector terminals within the connector portion of the body.

2. A cover according to claim 1, wherein the locking portion includes two resiliently deformable fingers formed integrally with the cover body, each finger being arranged to be resiliently deformed by insertion of a protruding male type motor terminal into the cover and having a locking projection engageable with a hole in the motor terminal when the motor terminal is fully inserted thereby preventing removal of the cover.

3. A cover according to claim 2, wherein each finger has an extension accessible from externally of the cover to permit manual deflection of the finger to disengage the locking projections from the holes in the motor terminals thereby releasing the motor terminals and allowing the cover to be removed.

4. A cover according to any one of the preceding claims, wherein the conductor means includes a noise suppression component.

5. A cover according to claim 4, wherein the noise suppression component is a voltage surge suppressor electrically connected across the motor terminals.

6. A cover according to claim 4, wherein the noise suppression component is a capacitor connected across the motor terminals.

7. A cover according to claim 4, wherein the noise suppression component is a choke connected in series between a respective motor terminal and connector terminal.

8. A cover according to any one of claims I to 6, wherein the conductor means comprises two conductors formed from conductive sheet material, each conductor having a C-shaped female terminal for engaging a male motor terminal, a spade type male terminal for engaging an appliance plug fitted to the connector portion, and a mechanical connection type terminal for engaging a lead of a noise suppression component.

9. A cover for an electric motor substantially as hereinbefore described with reference to the accompanying drawings.