EP1878825A1

EP1878825A1 - Washing and/or drying machine for domestic use

Info

Publication number: EP1878825A1
Application number: EP07112377A
Authority: EP
Inventors: Giuseppe Marchitto
Original assignee: IAR-SILTAL SpA
Current assignee: IAR-SILTAL SpA
Priority date: 2006-07-13
Filing date: 2007-07-12
Publication date: 2008-01-16
Also published as: ITTO20060105U1

Abstract

A washing and/or drying machine for domestic use, such as a machine for washing and/or drying laundry or a dishwasher, comprises an electric motor (6) having a casing (6a) which encloses a rotor (6b) and a stator (6c), a shaft (6d) being connected to the rotor (6c), which protrudes from the casing (6a). The machine (1) further comprises a soundproofing shell (10) surrounding at least partially the casing of the motor (6a). Preferably, the soundproofing shall (10) has a body with walls that are at least partially obtained by two or more superimposed layers of different material, and a fan (20) is mounted thereon, for cooling the motor (6).

Description

The present invention relates to the field of electric household appliances and has been developed with particular attention being paid to domestic washing and/or drying machines, i.e., laundry-washing machines, laundry-drying machines, machines for washing and drying laundry and dishwashers.
Machines of the type referred to above typically comprise one or more electric motors. For instance, it is known that laundry-washing machines, laundry-drying machines and the so-called "washer-driers" are equipped with a main electric motor, designed to cause the basket containing laundry undergoing treatment to rotate. Also dishwashers are typically equipped with at least one electric motor, belonging to the so-called "washing" pump, i.e., the pump used for circulating the treatment liquid within a tank of the machine, and for sprinkling it onto the dishes. Some laundry-washing machines are also provided with a pump for re-circulating the washing liquid, in order to increase effectiveness of the treatment.
Machines as referred to above typically comprise also a discharge pump having its own electric motor. In some solutions the same pump, with one single motor, is arranged and controlled so as to obtain both the re-circulation function and the liquid discharge function at suitable times during the treatment cycle.
Electric motors used in washing and/or drying machines of more conventional type are usually commutator motors or single-phase induction motors. The advantage of such types of motor lies in that they are little expensive and imply a relatively simple and cheap control electronics. Conversely, the drawback of such motors lies in that they are quite noisy, especially when driven at high speed. For instance, noise is particularly high in machines for treating laundry, when the motor for actuating the corresponding basket is driven at high speed for the spin-drying steps. Problems involving operating noise exist also for pump motors, especially in case of washing pumps for dishwashers.
Said drawback has recently been reduced by introducing into washing and/or drying machines three-phase electric motors. Such motors are distinguished by a high operating noiselessness, also at high rotation speeds. Conversely, three-phase motors used at present on washing machines for domestic use require a sophisticated and therefore expensive control electronics.
The present invention basically aims at providing a simple, cheap and reliable solution to the aforesaid drawback.
According to the present invention, such aim is achieved by a washing and/or drying machine for domestic use having the features of claim 1. Preferred characteristics of the machine according to the invention are indicated in the dependent claims.
The present invention shall now be described in detail with reference to the accompanying drawings, provided by way of mere non-limiting example, in which:

Figure 1 is a simplified schematic section of a washing and/or drying machine according to the present invention;
Figures 2 and 3 are perspective views, from different angles, of a soundproofing shell according to the invention, surrounding at least partially a motor of the machine of Figure 1;
Figure 4 is a schematic cross section of the shell of Figures 2 and 3.

Figure 1 shows in highly schematic way a machine for treating laundry according to the present invention, designated as a whole by 1. Let us assume in the following that the machine 1 is a front-loading laundry-washing machine, though the following description applies also to a washer-drier and to a laundry-drying machine, also of top-loading type.
The machine 1 comprises a cabinet 2 within which a tank 3 is elastically supported. A laundry basket 4 is rotatably mounted inside the tank 3. In the case shown by way of example, the basket 4 comprises one single rear hub 5, onto which a pulley 5a is keyed.
Reference numeral 6 designates as a whole an electric motor, which should be assumed here to be a commutator motor of the type commonly used on washer-driers. The motor 6 has a corresponding stationary frame or casing 6a, inside which a stator 6b and an internal rotor 6c are arranged. A drive shaft 6d is associated to the rotor 6c, which protrudes frontally from the casing 6a. Between the shaft 6d of the motor 6 and the pulley 5a a belt 7 is mounted, by which the motion of the shaft 6d can be transferred to the basket 4, so as to cause rotation thereof around a substantially horizontal axis, according to a technique widely known in the field.
The tank 3 is delimited by a front wall, a rear wall and a circumferential wall. In a lower area of the tank 3, from the circumferential wall, projections 3a for fastening the motor 6 protrude. To this purpose, the casing 6a has in its upper area flanges or brackets 6a', designed to be fastened to the projections 3a by way of suitable fastening elements (such as screws or bolts) and by placing therebetween resilient damping means (bushings of elastomeric material for instance). Anyway, the motor 3 is fastened to the tank 3 also in ways that are known per se in the field.
The machine 1 further comprises all elements that are commonly known for performing its characteristic functions (such as an electro-mechanical or electronic control system, suspension systems, counterweights, solenoid valves for water loading, discharge pumps, cables, pipes, etc.), which are not shown in the figure since they are not relevant to the description of the present invention.
According to the main aspect of the invention, the machine 1 is further equipped with a soundproofing shell, globally designated by 10 in Figure 1, which surrounds to a prevailing extent the motor 6, namely the casing 6a thereof. As shall be more evident from the following, in the preferred embodiment of the invention the body of the soundproofing shell 10 has walls that are at least partly formed by superimposition of at least two layers of material, having different functional characteristics. Moreover, in a particularly advantageous embodiment, to the soundproofing shell 10 is operatively associated a fan for favoring the cooling of the motor 6. To this purpose, the soundproofing shell 10 can further be provided with aeration/ventilation openings or holes.
In Figures 2 and 3 the soundproofing shell 10 is shown in different views and from opposite angles, together with the motor 6.
The shell 10 has a basically cup-shaped body 11, in which a front wall 11a, a rear wall 11b and a peripheral wall 11c can be identified, the latter being basically U-shaped. The upper edges of such walls of the body 11 delimit an upper opening of the shell 10, designed to face the circumferential wall of the tank 3. As can be seen in the figures, the hollow delimited by the body 11 is designed to house the motor 10, which is therefore surrounded to a prevailing extent by the shell 10. The assembly is such that the upper portion of the casing 6a of the motor, in which the brackets 6a' are provided for, points upwards, in the direction of the aforesaid upper opening of the body 11. As can be inferred also from Figure 4, the casing 6a is at least locally spaced apart from the shell 10, i.e., a number of regions of the casing are at a certain distance from walls of the body 11.
As mentioned above, in the embodiment of the invention that is now deemed as preferential, the walls 11a, 11b, 11c of the body 11 of the shell 10 are obtained at least partly by superimposition of several layers of different material.
In the case shown by way of example, the body 11 comprises an outer layer 12, made of a relatively rigid material. In the example, such material is a plastic material, such as for instance polycarbonate, but the outer layer 12 can also be made of metal material, for instance metal sheet.
One or more walls of the body 11, and preferably all the three of them, further comprise at least an inner layer of sound-absorbing material, such as for instance mineral wool or the like. As can be noted, the inner layer 13 faces directly the casing 6a of the motor 6.
Moreover, in the example shown here, between the layers 12 and 13 at least one intermediate layer is provided for, made of a relatively resilient material, such as for instance rubber or a tarred material, of the type commonly used for soundproofing washing tanks for dishwashers. The intermediate layer 14 can be made up for instance of boards or stripes of tarred material, which is glued onto the inner surface of the layer 12, making up the stiff part of the body 11; the inner layer of sound-absorbing material 13 is then glued onto the intermediate layer 14.
It should be noted that it is not strictly necessary that all the walls of the body 11 are wholly made up of the three layers of material, i.e., that the inner surface of the outer layer 12 is wholly covered by the layers 13 and/or 14. In the example shown here, for instance, the peripheral wall 11c is basically formed by way of the aforesaid three superimposed layers 12-14 (see Figure 4), whereas the front walls 11a and 11b are only locally made up of the three superimposed layers, although to a prevailing extent.
The outer layer 12, which - as was said - makes up the stiffer part of the shell 10, basically performs functions of support and of reduction of vibration transmission. The inner layer 13 performs the main function of soundproofing, by absorbing the noise generated by the motor 6 when running. The intermediate layer 14 is particularly designed to eliminate resonance phenomena and vibration transmission.
In the preferred embodiment of the invention, on the soundproofing shell 10 a cooling fan is mounted, globally designated by 20 in Figures 1 and 3, in particular an electric fan. The fan 20 comprises a respective body 21 housing a blower with its electric drive motor, supplied in a per se known manner. The operation of the fan 20 is managed by the control system of the machine 1, in ways that can vary depending on the selected implementation. In the simplest embodiment, the fan 20 can be activated in concomitance with the actuation of the motor 6, either continuously or intermittently. According to a more sophisticated, though however low-cost embodiment, the fan 20 can be started only when the temperature of the motor 6 - which can be detected by way of a sensing means - exceeds a pre-established threshold; when said sensing means (for example a PCT or NTC thermistor) detects temperature decrease below said threshold, the operation of the fan 20 is then interrupted.
The body 21 of the fan 20 is mounted at a through opening (not visible in the figures) made in a wall of the shell 10: in the case shown by way of example in the figures, the fan 20 is mounted on the rear wall 11b. In order to favor aeration/ventilation of the motor 6, the shell 10 is also provided with through holes, indicated with 15, preferably made on the wall of the body 11 being opposed to the one carrying the fan 20; in the case shown by way of example, therefore, said aeration/ventilation holes 15 are made in the front wall 11a of the body 11. It should be noted, concerning ventilation of the motor 6, that the casing 6a has been represented only schematically in the figures, but it is actually equipped with usual slots and passages enabling air circulation inside the casing itself.
The front wall of the shell 10 is suitably provided with a passage 16 for the shaft 6d protruding frontally from the casing 6a of the motor 6. In the preferred embodiment, said passage 16 is shaped as a substantially radial slot, extending from the upper edge of the front wall 11a up to a central region thereof, in which the shaft 6d can protrude frontally also from the shell 10. The slot-like shape of the passage 16, which opens on the upper edge of the front wall 11 a, enables to simplify the mounting of the shell 10, as shall be more evident from the following.
At least one wall of the shell, in the case shown by way of example the rear wall 11c, is further provided with a passage 17 for the electric wires for the supply and/or control of the motor 6. Such wires, which have not been shown in the figures for simplicity's sake, are designed for the connection to a terminal board of the motor 6, which can be seen schematically in Figure 4, where it is designated with 6e. The passage 17 for the wires is also shaped as a slot extending from the upper edge of the rear wall 11b of the body 11. The passage 17 can obviously be used, if required, also for the wires of the fan 20 and for the likely sensing means associated to the motor 6 (such as a known sensor of speed and/or angular position of the motor shaft, a temperature sensor, etc.).
The machine 1 according to the invention is further equipped with means for fastening at least locally the soundproofing shell 10 in a substantially fixed position with respect to the casing 6a of the motor 6. In the case shown by way of example, such means comprise at least one pair of through holes 18, made in the front 11a and rear 11b walls of the body 11, in an upper area of said walls. It should be pointed out that the brackets 6a' are provided with respective seats or passages 6a" used for engaging resilient damper elements and fastening elements, used for anchoring the casing 6a to the projections 3a of the tank 3 (see Figure 1). The through holes 18 of the shell 10 are substantially aligned, in particular coaxial, with the aforesaid seats 6a", as can be inferred in particular from Figure 4. Thus, for instance, the holes 18 can be threaded and receive screws or equivalent means - indicated with 19 in Figure 1 - whose front end engages with the aforesaid fastening elements of the brackets 6a' to the extensions 3a, so as to anchor in position the shell 10. In other possible embodiments, the screws or the like used for anchoring the casing 6a to the projections 3a can also be used for fastening in position the shell 10.
In the embodiment shown here, the motor 6 is mounted by exploiting the presence of the brackets 6a', with the corresponding seats 6a", and of the anchoring projections 3a provided in the lower area of the tank 3. The mounting can make use of cantilever pins of the projections 3a, designed to be fitted into the seats 3a, by placing therebetween elastic shock-absorbing means, bushings of elastomeric material for instance, which surround said pins; anchoring is then completed by means of screws or bolts tightening the brackets and projections. Once the motor 6 has been mounted and its supply/control wires have been connected to the terminal board 6e, the soundproofing shell 10 is placed on the motor 6 from below. As can be understood, such operation is extremely simplified thanks to the presence of the slot-shaped passage 16, by means of which the shaft 6d protruding frontally from the casing 6a represents no hindrance to the movement upwards of the shell 10 up to the mounting position; the same applies to the slot 17 making up the passage for the electric wires. When the shell 10 is in the pre-established position, into the holes 18 of the front 11a and rear 11b walls of the body 11 are fastened the corresponding screws 19, whose ends will abut against or engage onto the anchoring means of the brackets 6a' of the projections 3a of the tank 3.
From the above description the characteristics of the present invention are clear. In the machine according to the invention the presence of the soundproofing shell 10 enables to drastically reduce the noise of the motor 6, also during steps involving high-speed rotation, in particular during spin-drying. The enveloping structure of the shell 10, which surrounds the motor 6 to a prevailing extent, enables to obtain such noise reduction, in particular in combination with the multilayered structure of said shell, wherein the various layers perform different function of noise reduction/absorption, suppression of resonance phenomena, vibration reduction and support. The preferred use of the fan 20 and/or of the openings 15 for ventilation/air circulation prevents the possibility of overheating of the motor 6.
The above said advantages in terms of noise reduction of the motor 6 are achieved in an extremely simple and cheap manner. To this purpose it should be pointed out that the cost only of the control electronics of a three-phase motor for washing machines is on average of about 40 Euros, wherein the cost of the soundproofing shell 11, including the respective fan 20, is of about 4-5 Euros.
The invention has been described with reference to the electric motor designed to cause the actuation of a basket of a laundry-washing machine, of a washer-drier or of a laundry-drying machine. It is however clear that the electric motor designed to be surrounded at least partially by the shell provided according to the invention could be the motor of a pump, in particular a washing pump of a dishwasher or possibly of a laundry-washing machine, or also the electric motor of a discharge pump, still for a laundry-washing machine, a washer-drier, a drying machine, a dishwasher. In this light, obviously, the shape of the soundproofing shell can differ from the one shown here by way of example.
Obviously, provided that the basic idea underlying the invention remains the same, construction details and embodiments can widely vary from what is described and shown, without leaving the scope of the invention as defined by the claims that follow.

Claims

A washing and/or drying machine for domestic use, such as a machine for washing and/or drying laundry or a dishwasher, comprising an electric motor (6) having a casing (6a) which encloses a rotor (6b) and a stator (6c), a shaft (6d) being connected to the rotor (6c), which protrudes from the casing (6a), the machine (1) being characterized in that it further comprises a stationary soundproofing shell (10) surrounding at least partially the casing of the motor (6a), where in particular the soundproofing shell (10) is at least locally spaced apart from the casing (6a) of the motor (6).
The machine according to claim 1, wherein the soundproofing shell (10) has a body (11) with walls (11a, 11b, 11c) at least partly formed by superimposition of two or more layers (12-14) of different materials.
The machine according to claim 1 or 2, wherein on the soundproofing shell (10) a fan (20) is mounted, for cooling the motor (6), where in particular the fan (20) is mounted on a rear wall (11b) of the soundproofing shell (10), i.e., a wall facing the end of the casing (6a) opposed to the one from which the shaft (6d) protrudes.
The machine according to at least one of the preceding claims, wherein the soundproofing shell (10) has a wall (10a) provided with a passage (16) for the shaft (6d), where in particular the passage for the shaft (6d) comprises a slot (16) extending towards a central region of a front wall (11a) of the shell (10), starting from an edge of said wall.
The machine according to at least one of the preceding claims, wherein the soundproofing shell (10) has a wall (11b) provided with a passage (17) for electric wires for the supply and/or control of the motor (6), where in particular the passage for the wires comprises a slot (17) extending from an edge of the corresponding wall.
The machine according to at least one of the preceding claims, wherein the soundproofing shell (10) has aeration/ventilation passages (15), where in particular said passages (15) are configured as through holes and/or are formed in a front wall (11a) of the shell (10).
The machine according to claim 1, wherein the body (11) of the soundproofing shell (10) comprises at least three layers of different material (12-14).
The machine according to claim 2 or 7, wherein the layers (12-14) comprise at least one of:
- an outer layer (12) of substantially rigid material, in particular a plastic material,

- an inner layer (13), i.e., facing the casing (6a) of the motor (6a), which includes sound-absorbing material, such as mineral wool,

- an intermediate layer (14) including a substantially resilient material, such as rubber or tar.
The machine according to claim 1, wherein the soundproofing shell (10) is designed to be anchored in substantially fixed position using at least in part means (3a, 6a') used for fastening the motor (6) to further component or structure (3) of the machine (1).
The machine according to claim 1, wherein the soundproofing shell (10) is designed to be anchored to at least one of the casing (6a) of the motor (6) and a further component (3) of the machine (1).
The machine according to claim 10, further comprising means (18, 19) for locally anchoring the soundproofing shell (10) in a substantially fixed position with respect to the casing (6a).
The machine according to claim 11, wherein the anchoring means (18, 19) comprise one or more through holes (18) for respective fastening elements (19), in particular of the threaded type, where in particular the casing (6a) has one or more brackets (6a') for anchoring to a further component (30) of the machine (1), the bracket or brackets (6a') each defining a seat (6a"), and wherein the through hole or holes (18) of the soundproofing shell (10) is/are substantially aligned with a respective said seat (6a").
The machine according to one or more of the preceding claims, wherein the motor (6) is
- a motor for actuating a laundry basket (4), the machine (1) being a laundry-washing machine, a laundry-drying machine or a laundry washer-drier, or else

- a motor of a pump, the machine being a laundry-washing machine, a laundry-drying machine, a laundry washer-drier or a dishwasher.
The machine according to claim 13, wherein
- the casing (6a) of the motor (6) has brackets (6a') for anchoring to support projections (3a) protruding from a peripheral wall of a tank (3) in which the laundry basket is housed (4), and

- the soundproofing shell (10) opens towards a region of the peripheral wall of the tank (3) from which said support projections (3a) protrudes.
A domestic washing and/or drying machine electric motor soundproofing shell, the soundproofing shell (10) being designed to be mounted in a fixed position on the machine, to surround at least partially a stationary casing (6a) of said electric motor (6), the shell (10) having the features of one or more of claims 1 to 10.