Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-12-17
2001-07-24
Waks, Joseph (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C417S363000, C192S149000
Reexamination Certificate
active
06265799
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the constituent parts of a coupling between the load and rotor of a single-phase synchronous motor which transmits rotation to the load, such as the coupling between the rotor and the impeller of a drain pump, in order to eliminate noise and vibrations.
2. Prior Art
ES-2053372 (n
o
P9200335) describes a coupling of a drain pump impeller to the rotor shaft of its synchronous motor with a permanent magnetic rotor. The pump impeller has an internal cavity where the rotor shaft is coupled, sealed with a cap. At one end the rotor shaft for coupling to the impeller has an integral coupling cam, fitted with a radial drive catch, which moves back and forth in a free travel inside the impeller chamber for off-load pump starting. The coupling for rotation transmission is realized by means of a radial stopper integral with the impeller, and in its chamber it occupies a circular sector, which has a restricted angle in order to provide the rotor shaft and its drive catch with sufficient angle of free travel for starting the motor by vibration in either of the two directions of rotation. The drive catch engages afterwards with the impeller stopper and makes it turn at synchronous speed. To cushion the impacts of the drive catch against the impeller stopper in both directions of rotation the latter has a cushioning piece inserted made of elastomer material which protrudes laterally from both ends of the stopper in order to absorb the impacts and thereby reduce noise and vibration. This coupling solution has the drawback of being short-lived due to fatigue breakage of the cushioning stopper as a result of the heavy impacts against it, which cannot be remedied by making it thicker because said free angular play should not be reduced.
EP-514272 discloses a drain pump impeller coupling solution for transmitting the rotation of its synchronous motor in which a stopper integral with the impeller has cushioning devices formed or attached, consisting of springs in the form of flexible tabs on either side of the stopper. This solution also has a service life problem due to fatigue.
EP-474004 discloses a solution for the coupling of the rotor shaft to the rotor of a synchronous motor for transmitting rotation, which has an internal rubber ring attached to the rotor with two integrated stop lugs that impact against a radial cam drive catch attached to the rotor shaft, in a respective direction of rotation of the rotor, and it is an attached part made entirely of rubber affixed to the impeller. This solution also has a service life problem due to fatigue in the rubber cushioning ring attached to the impeller.
SUMMARY Of THE INVENTION
The object of the present invention is a coupling for the transmission of the rotor rotation to the load in a permanent magnetic rotor synchronous motor, such as a drain pump motor, as defined in claim
1
. The transmission coupling according to the invention is realized in a chamber formed either in the load or in the rotor, and it comprises a solution to prevent vibration and noise during the off load starting of the motor as well as while the engine is running off load, as for instance when there is hardly any water to discharge in a pump. The coupling has the advantage of its easy construction, since it simplifies the conformation of the impeller or the rotor through doing away with the integral stopper contained in the known solutions.
The cushion stopper is made of a single piece, of a regular configuration, which is fitted compressed in the coupling cavity between two surfaces substantially perpendicular to the rotor shaft. In the transmission coupling according to the invention two effects take place for the cushioning of the impacts that occur on the cushioning member, an elastic deformation of the cushioning member as a result of the impacts with the cam drive catch, and an angular displacement of the cushioning member, which extends the duration of the impact whilst its magnitude is decreased in relation to the known solutions.
The displacement of the cushioning member depends on its compression between the two aforesaid engaging surfaces, but the result obtained is not affected substantially by the state of the surfaces nor by the characteristics of the cushioning member material. To achieve such cushioning displacement through its conformation and angular extension, the cushioning member undergoes a friction force in the cavity, which is overcome in the motor starting interval of time by the impacts produced against the cam drive catch, whereas said friction force has to be higher than the force exerted against the coupling cam when the motor is running so that engagement takes place with the drive catch at synchronous speed, while the cushioning member remains stationary.
Besides cushioning the transmission noise and vibration, the transmission coupling according to the invention has a long service life as the cushioning stop member does not undergo any permanent deformation or substantial fatigue.
REFERENCES:
patent: 3657902 (1972-04-01), Cataldo
patent: 3977212 (1976-08-01), Johansson
patent: 4307584 (1981-12-01), Sandiumenge
patent: 4328879 (1982-05-01), Tone
patent: 4483685 (1984-11-01), Spasiano et al.
patent: 4750872 (1988-06-01), Palliser
patent: 4795402 (1989-01-01), Reichardt
patent: 4861240 (1989-08-01), Marioni et al.
patent: 6045448 (2000-04-01), Kern et al.
patent: 0320060A2 (1988-12-01), None
patent: 0474004A2 (1991-08-01), None
patent: 0514272A1 (1992-05-01), None
patent: 0487785A1 (1992-06-01), None
patent: 0551550A1 (1993-07-01), None
patent: 0561013 (1993-09-01), None
patent: 0551370B1 (1995-03-01), None
patent: 0723329A2 (1996-07-01), None
patent: 2053060 (1994-07-01), None
patent: 2053372 (1994-07-01), None
patent: 2235726 (1994-01-01), None
patent: 94/21026 (1994-09-01), None
Fagor S. Coop.
Fitzpatrick ,Cella, Harper & Scinto
Waks Joseph
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