Patent Description:
The household appliance to which the invention relates is preferably a large household appliance such as a washing machine, or similar household appliance equipped with a rotating drum driven by an electric motor.

The invention therefore finds useful application in the industrial sector of large household appliances, particularly washing machines, and related components.

It is well known that a washing machine comprises a tub, inside which a drum is housed, rotatingly driven by a drive belt. The belt is set in rotation by a pulley integral with the rotor of an electric motor.

The electric motor is generally fastened below the tub containing the rotating drum, in a rear position so as to align the drive pulley projecting to the rear with a driven pulley integral with the drum. To support the motor, a support is used which is coupled to the tub at four attachment points, two at the rear and two at the front, provided for the purpose. Socket connectors are provided at the attachment points of the tub, onto which corresponding eyelets, formed in the support, are inserted. Once the eyelets are engaged in the sockets, the relative position of the elements can be locked by means of a threaded rod that fits into the sockets themselves. The four attachment points stably constrain the motor to the tub, even in the presence of the vibrations that occur when using the household appliance.

Over recent decades, the size of the electric motors used in most washing machines on the market has been significantly reduced, particularly with the advent of synchronous motors.

On the other hand, the use of the four attachment sockets on the washing machine tub has been retained, both for reasons of standardisation and for reasons of stability of the support. In fact, it can be observed that the relatively high arm separating the rear and front attachments defines a constraining reaction torque that effectively counteracts the pulley tension.

An embodiment according to the prior art, taken from the utility model filed under number EN MI20070304 U on behalf of the Applicant, is schematically illustrated in <FIG>. In this figure, a washing machine <NUM> is shown comprising a tub <NUM> inside which there is a drum <NUM> rotatingly driven by a belt <NUM> moved by a pulley <NUM> integral with the rotor of an electric motor <NUM> fastened from above to the tub <NUM> by means of a support <NUM> according to the prior art. It can be seen that the support is constrained to tub <NUM> by means of front <NUM> and rear <NUM> attachments, which define a relatively large attachment perimeter, occupied only in its front part by the electric motor.

The size of the attachment perimeter in the embodiment of the prior art, which, as mentioned, meets the requirements of standardisation and stability, results on the other hand in a significantly larger footprint of the component than the actual dimensions of the electric motor. Obviously, these dimensions have an impact on the logistical costs of production and distribution, requiring larger volumes for the storage and transport of the device.

As a result, there is a need to streamline the fastening elements of the motor to the washing machine, while maintaining compatibility with existing washing machine tub attachments on the one hand, and the fastening stability of traditional fastening supports on the other, particularly under critical conditions such as high vibrations due to the spin cycle.

Another purpose of the invention is to reduce the plastic or other material used for the production of such fastening elements.

A further aim is to reduce the shipping and storage costs of such these supports due to the size of standard fastening supports.

Supports according to the prior art are disclosed in documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

The technical problem underlying the present invention is, thus, that of providing a fastening support for an electric motor with a significantly reduced volume, without impairing the compatibility and fastening stability characteristics guaranteed by supports according to the prior art.

The idea underpinning the present invention is to provide an abutment element integral with the support that abuts against a rear surface of the tub, exerting a constraining action to counteract the possible rotation of the support around the hinge defined by its front attachment points.

The abutment element thus performs the structural function delegated in the prior art to the rear attachment points, which are no longer necessary to guarantee the stability of the assembly. The latter can therefore be conveniently eliminated, allowing a considerable reduction of the dimensions in the motor's axial direction.

The aforementioned technical problem is therefore solved by a support for fastening an electric motor for rotatingly driving a drum of said appliance to a tub inside a household appliance, said support comprising:.

The abutment is not inserted in a dedicated seat of the tub, so that the support can be employed with existing washing machines without modifying the design of their tub.

Preferably, said abutment element raises substantially above with respect to a horizontal plane tangent to an upper surface of said attachment elements. Therefore, the abutment element can abut against the ribbed portion of the tub which is usually substantially above the attachment points.

As mentioned above, the solution according to the present invention allows only the front attachment elements to be used for fastening. Preferably, therefore, the support comprises two and only two attachment elements.

In a familiar manner, the attachment elements take the form of eyelets designed to accommodate respective connectors integral to the tub. The connectors are preferably cylindrical sockets to which the eyelets are constrained by means of threaded rods.

Preferably, the abutment element is arranged at a distance from both attachment elements, i.e. it neither overlaps with them nor is located in close proximity to them.

In particular, in a preferred solution, the abutment element is elevated to a position substantially intermediate with respect to that of the two abutment elements.

Preferably, the abutment element is in fact positioned on the centreline of the support, while the two attachment points are traditionally lateral thereto.

Still preferably, with a view to keeping the device as compact as possible, the abutment element is essentially coplanar with respect to the two attachment elements. In particular, all three elements can be provided on the rear surface of the support, which is basically aligned with the rear surface of the washing machine tub.

Said abutment element comprises an appendage which is radial with respect to the main body, shaped on the upper part in order to adapt to a rear surface of the tub.

Still preferably, the aforementioned radial appendage rises to a higher level than the attachment elements.

Preferably, the appendage is shaped at the top like an L facing the forward direction of the support. In particular, the opening of the L faces forward and upwards with respect to the support. Thanks to this conformation, the appendage is able to abut firmly against a lower edge of the washing machine tub.

The aforementioned appendage comprises, at least in its upper portion, two parallel ribs designed to house therebetween a ribbing feature of the rear wall of the tub. This not only adapts to the ribbed shape of the rear surface of the washing machine tub, but also allows for precise positioning of the support in a central position in relation to the washing machine tub.

On the inner surface of the two parallel ribs, friction means can advantageously be applied, e.g. elastomer shims, which work in compression on the opposing sides of the tub rib, in order to provide a further frictional blockage.

Preferably, this appendage is made integral with the main body. In particular, the appendage - as well as the side wings bearing the connecting eyelets - can be made together with the main body by means of a single molding operation, preferably from thermally conductive plastic material.

In a preferred embodiment, the electric motor is integrated into the support. In particular, the electric motor can be enclosed in a casing defined by the main body.

As is well known, the electric motor comprises a rotor which can be rotated with the pulley projecting at the rear and a stator integral with the main body. The electric motor may be of the permanent magnet synchronous type and may have an internal rotor.

The casing is preferably made of plastic and co-molded above the stator. Alternatively, the casing can be made in a traditional manner, e.g., with metal shells, preferably aluminium.

Preferably, the aforesaid casing comprises two circular panels at the front and rear joined by a side edge, extending along the side perimeter of the casing.

The casing preferably comprises, on its rear panel, a hub extending outwards from which the pulley of the electric motor emerges.

Preferably, the casing comprises a rear cover that is removably attached to the rest of the main body, e.g., by means of fastening screws.

Advantageously, the cover can allow a maintenance person to access the shaft/rotor block, being able to pull it out if necessary.

Also advantageously, the cover can support one of the bearings supporting the rotor shaft, the other being inserted into the rear panel of the casing.

Preferably, the fastening support can dissipate heat, acting as a heat sink.

The support is part of a tub/motor assembly comprising a tub of a household appliance comprising at least two attachment points and a rear surface; an electrical motor; and the support itself; wherein the two attachment elements are coupled to the attachment points at the bottom of the tub and the abutment element abuts against a rear surface of the tub, above said attachment points, without being inserted in a dedicated seat of the tub; wherein the main body of the support supports the electrical motor in a fixed position with respect to the tub, a pulley of said electric motor protruding at the rear with respect to said main body.

The characteristics and advantages of the present invention will result from the following description with reference to the accompanying drawings provided by way of indicative and non-limiting example.

With reference to <FIG>, <NUM> indicates overall a support according to an embodiment of the present invention.

The support <NUM> is illustrated in the figures in its normal use configuration. The positions and orientations, relative and absolute, of the various elements that make up the device, defined by terms such as upper and lower, top and bottom, horizontal and vertical or other equivalent terms, must always be interpreted with reference to that configuration. Other terms such as front or front and rear, and their equivalents, should be interpreted considering the normal use configuration of the washing machine, which has the loading door at the front and the belt drive connecting the electric motor and drum at the rear.

The support <NUM> is intended to perform a support function for the electric motor <NUM>. In turn, the support <NUM> is supported by the tub <NUM>, which is equipped with traditional type fastening means able to support a motor.

In the preferred embodiment described herein, the electric motor <NUM> is integrated into the support <NUM>, i.e. the two form a single entity that can be individually handled.

The electric motor <NUM> is preferably of the synchronous type, and comprises an inner rotor <NUM> with permanent magnets and an outer stator <NUM> with windings, separated in a known manner by an air gap. The rotor <NUM> comprises a central hub splined to a shaft <NUM> rotatable about an axis of rotation X. The shaft <NUM> is supported by two bearings 39A, 39B and has a free end on which a pulley <NUM> is splined to drive the belt that moves the washing machine drum.

The support <NUM> comprises a main body <NUM>, which constitutes in particular a thermally conductive plastic casing <NUM>, co-molded directly onto the stator <NUM> of the electric motor <NUM>, so as to accommodate it inside.

The casing <NUM> therefore has a cylindrical shape, defined by a rear circular panel <NUM> and a circular front panel <NUM>, connected by a side edge <NUM>.

The rear circular panel <NUM> has a central portion B from which a projecting hub <NUM> emerges externally, from which in turn the end portion of the shaft <NUM> emerges equipped with a pulley <NUM>. Two pairs of ribs <NUM> and <NUM> radially project from the projecting hub <NUM>, which are connected by two diverging arms radially projecting from the rear circular panel <NUM>. Two full braces <NUM> are connected to each other on either side of each of the diverging arms. At the two ends of these diverging arms as many attachment elements 23A, 24A are formed, which in this case take the form of eyelets for housing the respective socket connectors 23B, 24B on the rear surface of the washing machine drum. In the socket connectors 23B, 24B, screws are introduced in a known way.

Second reinforcing ribs <NUM> radiate out from the projecting hub <NUM> along the lower portion of the rear circular panel <NUM>.

The casing <NUM> also features a terminal block <NUM> on the outside, projecting from the side edge <NUM>, which allows power and control cables to be connected.

From the projecting hub <NUM> an abutment element <NUM> extends vertically upwards, having a fork structure, which defines an upper appendage <NUM> projecting from the main body <NUM> of the support <NUM>.

The abutment element <NUM> consists of two parallel ribs <NUM> that depart vertically from the projecting hub <NUM>. These ribs <NUM> are connected at the rear by a bridge <NUM>, but remain separated in their front portion. The two ribs <NUM> define a fork with an L-shaped side profile, which abuts against the tub <NUM> of the washing machine <NUM>, as can be seen in <FIG>. In particular, a rear rib <NUM> of the tub <NUM> is introduced between the two ribs <NUM>. The base of the L-shaped profile connects with a cylindrical base <NUM>, raised from the side edge <NUM> and separated from it by two feet <NUM>.

Advantageously, in the embodiment depicted here, two elastomer shims <NUM> are applied, e.g. by adhesive, to the two inner surfaces of the ribs <NUM>, which provide a further frictional blockage on both sides of the rib <NUM>.

This abutment element <NUM>, as discussed earlier in the summary of the invention, fulfils the purpose of ensuring the stability of the device.

At the rear, the casing <NUM> is formed by a circular panel <NUM>, which centrally has an opening closed by a lid <NUM>. The stator <NUM> can be positioned and removed through the opening. The cover <NUM>, which houses one of the bearings 39A supporting the shaft <NUM>, is fastened to the casing <NUM> by means of fastening screws <NUM>.

An advantage of the present invention derives from its compact and space-saving design, due to its small axial dimensions and quasi-planar extension, which greatly facilitates storage and transport operations.

Another advantage of the present invention lies in the structural solidity of the attachment defined by the support on the washing machine tub.

A further advantage lies in the limited production and assembly cost of the support, thanks to the monolithic structure that integrates the electric motor within it.

Another advantage is due to the use of thermoplastic overmolding, which allows optimal heat dissipation.

Claim 1:
Support (<NUM>) for fastening an electric motor (<NUM>) to a tub (<NUM>) inside a household appliance for rotatingly driving a drum (<NUM>) of said household appliance, said support (<NUM>) comprising:
a main body (<NUM>) designed to support the electrical motor (<NUM>) in a fixed position with respect to the tub (<NUM>), a pulley (<NUM>) of said electric motor (<NUM>) protruding at the rear with respect to said main body (<NUM>);
two attachment elements (23A, 24A), designed for the coupling with respective attachment points of the tub (<NUM>) in an assembled configuration, said attachment elements (23A, 24A) being arranged above and at the rear with respect to said main body (<NUM>)
wherein the terms front and rear, above and below should be interpreted considering the support (<NUM>) mounted on a household appliance in its normal use configuration, the household appliance having a loading door at the front and a belt drive connecting the electric motor (<NUM>) and drum (<NUM>) at the rear;
said support (<NUM>) further comprising:
at least one abutment element (<NUM>) protruding above and in a rear position with respect to the main body (<NUM>), said abutment element (<NUM>) being designed to be arranged, in an assembled configuration, abutting against a rear surface of the tub (<NUM>) without being inserted in a dedicated seat of the tub (<NUM>);
wherein said abutment element (<NUM>) comprises an appendix (<NUM>) which is radial with respect to the main body (<NUM>) and shaped on the upper part in order to adapt to a rear surface of the tub (<NUM>);
characterized in that said appendix (<NUM>) comprises, at least in its upper portion, two parallel ribs (<NUM>) designed to house therebetween a ribbing feature (<NUM>) of the rear wall of the tub (<NUM>).