GB2235726A

GB2235726A - Household appliance pump lost motion drive, seal and bearing arrangement

Info

Publication number: GB2235726A
Application number: GB9016770A
Authority: GB
Inventors: Uriarte Javier Errasti
Original assignee: Fagor Electrodomesticos SCL
Current assignee: Fagor Electrodomesticos SCL
Priority date: 1989-08-04
Filing date: 1990-07-31
Publication date: 1991-03-13
Anticipated expiration: 2010-07-31
Also published as: DE4024194A1; IT1243484B; GB2235726B; FR2650636B1; IT9021187A1; GB9016770D0; DE4024194C2; FR2650636A1; IT9021187A0; ES2019491A6

Abstract

The pump comprises a pump body 1 coupled to a motor body 2 with a cylindrical neck 3 housing the impeller 4, the latter mounted between bearings 6 (and 7 Fig 1) which are moreover axially mounted on the relevant live axle 5 at the upper end of which is mounted the wheel 8. A disk-shaped part 9 having a sealing gasket (15) and a cap 18 is provided to prevent access of dirt and particles to the impeller, this being assisted by a felting 26. There is also provided another gasket 24 provided between the cap 18, the pump body 1 and the motor body 2 to provide a suitable sealing system. The arrangement is said to protect the impeller-wheel transmission from any dirt and suspended particles, at the same time muting noise and quenching vibration during start-up since the o-ring seal joined to the disk-shaped body brakes the live axle during start-up. <IMAGE>

Description

IMPROVEMENTS IN SYNCHRONOUS -MOTOR HOUSEHOLD APPLIANCE PUMPS

SPECIFICATION

PURPOSE OF THE INVENTION - The present invention relates to a series of improvements in household appliance pumps driven by a synchronous motor, pumps whose live axle is fitted with the relevant wheel capable of certain angular travel to allow loadless starting of the motor, such type of pumps moreover including a permanent magnet impeller mounted between two end bearings housed in a cylindrical neck and closed at one of its ends, which neck is obviously part of the respective pump housing.

The purpose of the invention is to provide the structure of this sort of pumps, whose concept has just been defined, with a series of innovations and improvements resulting in a longer life and more efficient operation of the pump as a whole.

BACK OF THE INVENTION Synchronous motor driven household appliance pumps are equipped with a permanent magnet impeller that can during operation attract any metal particle suspended in the liquid to be pumped, which particles therefore accumulate on the actual impeller and can actually block the PUMP - Because the motor is synchronous,, the relevant wheel cannot be stiffly coupled to the impeller, and some degree of freedom must exist therebetween,, for the product would otherwise become extremely expensive.

Now then, this degree of freedom between the impeller and the wheel must be ensured throughout the pump's life, and it will hence 1 obviously be necessary to try to prevent dirt and small particles suspended in the liquid to be P from hindering free play of the wheel with the inpeller, at the respective angular area.

Furthermore, the said play between the inpeller and the wheel together with the fact that the synchronous motor can start in any direction,, and that it must at the same time rapidly reach the speed of synchronism, leads to strong inpacts during start-up, which inpacts are also tried to be, absorbed to avoid rebounding causing annoying noise and vibration.

Another characteristic that pumps of this sort must fulfil, or at any rate try to do so, is an efficient sealing system, and this has not yet been fully and definitively achieved.

It is also convenient to keep the top bearing in its mounting position, in order to prevent stresses thereon to cause the sinne to rotate and travel axially.

Known household appliance pumps actually fail to fulfil all these requirements, or at least not with the efficiency and definitiveness one would wish.

DESCRIPTION OF THE INVENTION

The inprovements in the said sort of pumps fully solve the foregoing probl by means of sinple solutions entailing a small cost, in both the sort of parts required and their easy assembly.

An objective hereof is to provide the pump with a system or means Preventing dirt and metal particles from reaching the ller area.

This system or means involve a cap that prevents water from directly reaching the bearing, for it m the same go through a sort of labyrinthine path, between the same and a disk-shaped element or o- 2 ring carrier part that rotates locked with the wheel itself, reducing the amount of dirt and particles that can go through it.

A felting has also been provided to act as retaining element for solid particles going toward the impeller area, which felting is located within the cap, between the top bearing, a cup-shaped lap of the said cap and the aforesaid disk-shaped element or o-ring carrier part.

Another purpose or improvement of the invention is to provide the pump with means for preventing the dirt and particles suspended from affecting the inpeller-wheel transmission, which latter is based upon a drive cam locked to the axle itself, the cam being assisted by an abutment provided on the wheel and which, upon meeting a drive pin provided in such cam, brings about rotation of the whole assembly.

As aforesaid, the wheel is enclosed within the disk-shaped body or o-ring carrier part, since both avail of hermetic coupling means, at the same time as the o-ring seal provided by such disk-shaped body acts as brake and ensures among others watertightness between the axle and the said body or disk-shaped element, preventing water and hence dirt from reaching the inside of the wheel, thereby ensuring that free play between the drive cam and the wheel exists for a long time.

Another improvement or purpose hereof is to provide the pump with a system to mute noise and quench vibration during start-up.

In this sense,, given that in a synchronous motor the speed of synchronism must be attained in a few milliseconds, the impeller and hence anything locked to the same gathers very significant accelerations. leading to strong impacts in the wheel when the drive cam stumbles upon the wheel abutment, making the latter accelerate sharply and causing some rebounding and vibration that delay start-up, and leading during that time to a hammering, between the wheel and the cam, that results in noise that should obviously really be minimised.

3 This is achieved by means of the brake o-ring seal that results in tightening on the axle, to achieve some coupling between the impeller and the wheel that means that when the drive can stumbles upon the wheel,, it does not accelerate unduly,, and hence there is no rebounding and startup is quieter.

This degree of coupling is very significant, for if it is weak it does not fulfil its purpose, and if it is undue, it can render start-up of the pump impossible.

Now then, the degree of coupling depends on how much the o-ring is tightened between the axle and the housing Where it is located.

Given that the axle point has very small tolerances as is also the case of the seal width, the only parameter that must be controlled to ensure tightening within certain limits is the diameter of the housing wherein the o-ring is mounted, which dimension can be easily controlled as it is an injected plastic part that can be obtained without any problems within small tolerances.

As to this point, other aspects that could influence the degree of coupling could be the surface finish of the axle and the disk-shaped body or o-ring carrier part, but as the axle is trued up it has a perfectly defined finish and so has the disk-shaped body, being injected.

Another improvement or purpose of the invention is to achieve a sealing systen, this being attained by tightening an o-ring seal provided between a rin carried by the motor body and the pump body.

The pump body, since the motor is sonous and can rotate in either direction, needs a central outlet, which prevents the pump body from preventing axial travel of the o-ring seal throughout its perimeter, wherefore poor sealing is a risk.

4 1 J 1 Such disadvantage is solved according to the subject hereof by means of the cap mentioned first above, for the latterfs perimeter has been provided with a rim preventing axial travel of the aforesaid oring seal itself.

Finally, another improvement subject of the invention consists in providing the top bearing with an efficient and novel means of attachment, whereby the cap is provided with a gearing that engages another gearing provided on the said bearing, to prevent radial rotation. Axial travel of such bearing is prevented because the cap is held by a pump body spring.

DESCRIPTION OF THE DRAWINGS

In order to provide a fuller description and contribute to the complete understanding of the characteristics of this invention, a set of drawings is attached to the specification which, while purely illustrative and not fully comprehensive,, shows the following:

Figure 1.- Is a view showing the constituent parts and components making up the housing appliance pump made with the improvements subject hereof,, and namely a vertical cross-section thereof.

Figure 2. - Is a view of the pump as a whole and largely a crosssection thereof, with all its parts in the mounting position.

PREKERRED EMBODIMENT OF THE INUSTION In the light of these figures it can be seen that the subject pump comprises the relevant pump body (1) and the motor body (2), the latter provided with a cylindrical neck (3) housing the relevant impeller (4) through which the live axle (5) passes,, such impeller (4) being 'mounted between a pair of bearings (6) and (7).

The top end of the live axle (5) is fitted with the relevant -bearing (8) capable of some angular travel to allow loadless start-up of the motor.

Now then., based upon these characteristics, one of the improvements consists in that a disk-shaped element (9) is coupled on the actual live axle (5) and then the cap (18), coupled tightly to the mouth (10) of the actual wheel (8) housing, and which housing, generally numbered (11),, receives a drive cam (12) axially housed in the fdtmy--r and provided with a side rib (13), complementing another rib (14) provided on the inner periphery of the said wheel (8) housing, so that as the can (12) is mounted on or rigidly coupled to the axle (5), when the latter and in essence the can (12) turns, such wheel (8) shall turn whenever the abutments or ribs (13) and (14) meet.

Adjustment of the disk-shaped body (9) on the wheel (8) takes place as both are provided with hermetic coupling means, besides an oring seal (15).

Similarly, an o-ring seal (15) provided in this disk-shaped body (9) provides the relevant sealing, preventing water from going inside.

The disk-shaped element or body (9) has a perimetric throat (16) wherein plays the free edge (17) of a cup-shaped lap of a cap (18) coaxial with the live axle (5), and disposed in the actual pump body (1), so that such lap where the free end (17) is defined,. provides a labyrinthine passage between the operative wheel (8) area or chamber and that where tJhe motor impeller (4) is located.

Turning to the top bearing (6), the sam is fitted with a Perimetric gearing (19), On the base OPPOsed to the ller (4), complementing another gearing (20) provided on the lower cap (is) edge,, Which gearings (19) and (20) assist each other in the radial and angular locking of the bearing with regard to the said cap (18), 6 1 t, t whereas these two elements are locked axially through an internal rib (21) provided in the pump body (1).

As to the motor (3) body, where it couples to the pump body (1), it is provided with a rim (22), and further inside with a concentric divider (23) defining a notching where an o-ring seal (24) is located, axially positioned by a ridge (25) in the cap (18) and deformed by the inner surface (27) of the pump body (1).

kth such structural features, dirt and particles do not reach the impeller (4), by action of the disk-shaped element (9), o-ring seal (15) and cap (18), and dirt and suspended particles are also prevented from going toward the impeller-wheel transmission, all of this being assisted by a felting (26) housed in the top bearing (6) and the cap (18), the felting being cylindrical and having the relevant axial bore for passage of the live axle (5).

We feel that the device has now been sufficiently described for any expert in the art to have grasped the full scope of the invention and the advantages it offers.

The materials, shape, size and layout of the elements may be altered provided that this entails no modification of the essential features of the invention.

The terms used to describe the invention herein should be taken to have a broad rather than a restrictive meaning.

7 CIAM 1. - improvements in synchronous motor driven household appliance p,, of the sort where the motor inpeller is mounted on end bearings housed in a cylindrical neck and closed on one of its ends of the pump housing, whose live axle is fitted with such pump's wheel capable of some angular travel to allow loadless starting of the motor, in such direction of rotation as is more favourable at any given moment, essentially characterized in that a disk-shaped element is provided on the said live axle coupling tightly to the mouth of the 1 housing for the drive cain stiffened to the axle, establishing a barrier toward such housing for any solid element dragged by the pumped water,, it further being foreseen that this disk-shaped element, define a perimetric throat wherein plays the free edge of a cup- shaped lap, coaxial with the live axle and projecting from a cap established inside the pump body, so that such lap in turn provides a labyrinthine passage between the operative wheel area or chamber and that where the motor impeller is located.

2.- Improvements in synchronous motor driven household appliance pumps,, in accordance with claim 1, characterized in that inside the cap, between the top bearing, the cup-shaped lap of such cap and the disk-shaped element assisting the wheel, is provided a felting acting as retaining element for solid particles toward the impeller area.

3.- Improvements in synchronous motor driven household appliance pumps, in accordance with claim 1, characterized in that the diskshaped element moreover constitutes the physical support for an oring, for which purpose it is provided with an inner perimetric notching, which o-ring acts as brake element for the synchronous motor axle during start-up and is duly sized for the friction on the axle not to prevent or unduly hinder such start-up.

4.- improvements in synchronous motor driven household appliance pumps, in accordance with claim 1, characterized in that the motor body 8 1 is provided with a perimetric rim where it couples to the pump body, defining with. the latter a likewise perimetric throat wherein is housed a sealing gasket, deformed for hermetic sealing of the assembly, by another rim provided on the cap periphery and that is located at the mouth of the said throat.

5.- Improvements in synchronous motor driven household appliance pumps, in accordance with claim 1, characterized in that the top bearing is provided with a perimetric gearing at its base opposed to the m6tor impeller, complementing another gearing provided in the cap, which gearings radially or angularly lock the cap, while both elements are axially locked through an internal rib of the pump body, acting on the cap periphery.

6. A synchronous motor driven household appliance pump substantially as hereinbefore described with reference to the accompanying drawings.

9 Published 1991 atMe Patent Office. State House, 66/71 HighHolborn, IA)ndonWC I R41?. Further copies maybe obtained from Sales Branch. Unit 6. Nine Mile Point. Owmiefinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray, Kent