[0001] This invention relates to a method for fixing to a washing machine tub the electric
motor which drives the drum positioned in the tub. The invention also relates to the
resultant washing machine. Various methods are used for fixing the motor to the tub.
For example in EP-A-1 0413093 the motor is fixed to the spider structure which supports
the tub. One of the spider arms is used as a fixing support for the motor. The motor
bearing plate at the motor drive end carries an arm provided with a pin mounted in
such a manner as to be able to rotate within the spider arm via a rubber/metal bush.
The arm carried by the plate is fixed to the spider arm by a screw means positioned
in an arcuate slot in correspondence with the bearing plate. This arrangement is supposed
to facilitate motor assembly. It is however complicated, it seriously stresses the
mechanical parts and does not adequately exclude vibration or noise.
[0002] In another arrangement the motor bearing plates are provided with pins which are
inserted via nylon bushes into holes present in appendices on the tub. This known
arrangement does not allow take-up of slack, nor does it eliminate vibration and noise.
[0003] A further arrangement which has the advantage of nullifying slack and eliminating
noise and vibration is however particularly complex in that fixing is by bolts inserted
through two stop washers, a rigid spacer, a rubber damping block and a tightening
nut.
[0004] The main object of the present invention is to provide a fixing method which besides
being considerably simpler than the known methods enables slack, noise and vibration
to be eliminated.
[0005] A further object of the present invention is to provide a washing machine comprising
a motor fixed by the method of the invention. These and further objects which will
be apparent from the detailed description given hereinafter are attained by a fixing
method and washing machine the inventive aspects of which are defined in the accompanying
claims.
[0006] The invention will be more apparent from the detailed description of a preferred
embodiment thereof provided hereinafter by way of non-limiting example with reference
to the accompanying drawing, on which:
Figure 1 is a partial vertical section taken through the motor support pins;
Figure 2 is a schematic section taken through one of the pins and showing the distributor
by which the pin is coated with silicone rubber.
[0007] As is well known, washing machines comprise a tub 3, a clothes drum 5 rotatably supported
within the tub 3, an electric motor 10 supported by the tub, and a transmission comprising
a belt 4a and pulleys 4 for transmitting motion from the motor to the drum 5. Whatever
arrangement is used for fixing the motor to the tub, it must be possible to adjust
the tension in the belt 4A. This is achieved by supporting the motor 10 on a geometrical
axis 1 parallel to its shaft so that it can be angularly shifted about this geometrical
axis until it reaches the angular position which gives correct operation of the belt.
When in this angular position the motor is locked by a nut and a bolt which passes
through both an arcuate slot and a cylindrical hole, one for example in a part of
the tub and the other in a part of the motor. According to the invention the said
geometrical axis 1 pertains to two spaced-apart coaxial pins projecting in the same
direction and integral with the tub 3, which as is well known is constructed of a
filled synthetic material. Before mounting the motor on the tub, a coating 11 of silicone
rubber in the pasty state (see Figure 2) is applied to said coaxial pins 2.
[0008] This application is achieved by injection using a conventional dispensing gun, not
shown, the exit of which is connected to a tube 20 having its end mounted on a tubular
appendix of a distributor indicated overall by 22. The distributor 22 comprises a
tubular cylindrical part 23 closed at one end and open at the opposite end. The inner
diameter of the part 23 exceeds that of the pin 2 by twice the thickness of the coating
11. Against the closed end of the distributor there adheres a disc 24 of synthetic
material such as teflon which defines the inner length (L) of the tubular part 23.
[0009] To apply the silicone rubber coating 11 the distributor is mounted on the pins 2
as shown in Figure 2 and is removed after the application. Corresponding eyelets 7
provided on the bearing plates 8, 9 of the electric motor 10 are mounted on the thus
coated coaxial pins 2, the motor axis being indicated by 13 and being parallel to
the axis 1 of the pins 2.
[0010] After a certain time the silicone rubber passes from the pasty state to the rubbery
state without volume change, to form an intermediate layer between the pins 2 and
the eyelets 7 which adheres securely to the pins 2, to nullify slack and eliminate
vibration and noise in a simple and effective manner.
[0011] The invention also includes an embodiment in which the eyelets 7 are provided with
a dead hole instead of a through hole.
1. A method for fixing to a washing machine tub (3) the relative electric motor (10)
which by means of a belt transmission (4, 4A) drives the drum (5) rotatably supported
within the tub (3), the motor (10) being supported on a geometrical axis (1) parallel
to its own axis (13), characterised in that the axis (1) on which the motor (10) is
supported pertains to two spaced-apart support pins (2) extending in the same direction
and integral with the tub (3), a coating (11) of silicone rubber in the pasty state
being applied to said pins (2), support eyelets (7) provided on the motor (10) being
mounted on said pins (2) after said application.
2. A washing machine comprising a tub (3), a motor (10) supported by the tub (3), a clothes
drum (5) mounted within the tub (3) and a belt transmission (4, 4A) for transmitting
motion from the motor (10) to the drum (5), the motor (10) being supported on a geometrical
axis (1) parallel to the axis (13) of the motor (10), characterised in that said geometrical
axis is defined by two equidirectional pins (2) integral with the tub (3), eyelets
(7) of the motor (10) being mounted on said pins (2), and a silicone rubber layer
(11) being interposed between the pins (2) and the eyelets (7).
