GB2283132A

GB2283132A - Plural bearing bush assembly

Info

Publication number: GB2283132A
Application number: GB9319927A
Authority: GB
Inventors: Philip Lam; Roma Chan
Original assignee: Chiaphua Components Ltd
Current assignee: Chiaphua Components Ltd
Priority date: 1993-09-28
Filing date: 1993-09-28
Publication date: 1995-04-26
Also published as: DE9415632U1; GB9319927D0

Abstract

An electric motor has bushes 20 and 21 supporting its rotor shaft 10 for rotation. In order to adapt or improve the life of the motor for special applications e.g. a vibratory motor an extra like hush 24 is added. <IMAGE>

Description

Electric Motor The invention relates to electric motors.

The invention relates more especially to relatively small and very small motors used in domestic appliances. The invention has particular application in vibratory motors such as are used foot massaging devices.

Conveniently many such electric motor include bush bearings which are usually sufficiently strong and long lasting for normal use. Clearly if a motor is subjected to excessive loads or special duties stronger forms of bearings may be used such as roller race bearings.

Generally stated, such changes significantly increase the cost and also reduce flexibility in mass production of various types of motor for different applications especially as applied to one manufacturing facility.

It is an object of the invention to overcome or at least reduce such problems.

According to the invention there is provided an electric motor having a motor shaft and bush bearings for the shaft, and a support at each end of the motor, each support holding one bush, in which at least one of the supports holds a second bush adjacent its other bush.

Each bush preferably has a generally spherical outer surface and is loosely held so as to allow the bush to self-align with the shaft.

Each support may be shaped to press and hold laterally against a side of each respective bush and a flexible retainer provided to hold and laterally bias the other side of the bush against the support.

The support which holds two bushes may be shaped to press laterally against the two bushes in opposite directions, and the second bush is held in position by a bracket mounted on the support.

The supports comprises brackets fixed to a stator assembly of the motor1 or at least one of the support comprises an end wall of a motor casing.

An fractional horsepower AC electric motor according to the invention will now be described by way of example with reference to the accompanying drawing which shows an exploded sectional elevation of the motor.

Referring to the drawing, the motor has a shaft 10 carrying a rotor 11. The rotor 11 fits inside a laminated stator assembly 12 and support brackets 13 and 14 are held against opposite ends of the stator assembly 12 by nuts 15 and bolts 16. Ancillary components include spacers 17, felt washers 18 and phenolic washer 19.

The shaft 10 is supported in position by two bushes 20 and 21. The bushes have generally spherical outer surfaces and the brackets 13 and 14 are shaped to press laterally against the outer surfaces of respective bushes.

Resilient retainers 22 and 23 are mounted to the brackets and hold the bushes 20 and 21 in position with sufficient force while allowing a looseness of fit such as to allow the bushes to self align with the shaft 10. In general terms at least, the motor so far described is already known.

In embodiments of the invention, a further bush 24 is provided mounted adjacent the bush 20 and held by and against the bracket 13. An auxiliary bracket 25, which is screwed to the bracket 13 when the motor is fully assembled, holds the bush 24 in position. It will be noted that the bush 24 is also held in a manner so as to be self-aligning with the shaft 10.

It will also be noted that the bushes 20, 21 and 24 are all the same, simplifying standardisation of components for assembly, and that the brackets 13 and 14 are or can be the same. Indeed, in order to change a particular motor to have a "double bush" at one end, or both ends

desired, an auxiliary bracket and extra bush can be simply added.

As discussed earlier, motors which are to be used for certain or special applications, including vibratory motors where for example an eccentric flywheel is fitted to one end of the shaft 10, the extra bush 24 is easily added to what may be otherwise a standard motor, say.

In the described embodiment, the bushes are supported by brackets. When the motor is provided with a casing the bushes may be supported by one or both end walls of the casing if desired.

Claims

1. An electric motor having a motor shaft and bush bearings for the shaft, and a support at each end of the motor, each support holding one bush, in which at least one of the supports holds a second bush adjacent its other bush.

2. An electric motor according to claim 1, in which each bush preferably has a generally spherical outer surface and is loosely held so as to allow the bush to self-align with the shaft.

3. An electric motor according to claim l or 2, in which each support may be shaped to press and hold laterally against a side of each respective bush and a flexible retainer provided to hold and laterally bias the other side of the bush against the support.

4. An electric motor according to claim 3 in which the support which holds two bushes may be shaped to press laterally against the two bushes in opposite directions, and the second bush is held in position by a bracket mounted on the support.

5. An electric motor according to any one of claims 1 to 4, in which the supports comprises brackets fixed to a stator assembly of the motor.

6. An electric motor according to any one of claims 1 to 4, n which at least one of the support comprises an end wall of a motor casing.

7. An electric motor substantially as herein described with reference to the accompanying drawing.