Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1999-06-28
2000-11-14
Mullins, Burton
Electrical generator or motor structure
Dynamoelectric
Rotary
310 36, 310181, 310 49R, 310254, 335266, H02K 2600, H02K 41035, E05B 4700
Patent
active
061474274
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to an electromotive actuating device having a movable member and a stationary member comprising at least a first excitation part adapted to generate a magnetic flux, particularly a constant magnetic flux, and at least a second excitation part adapted to generate a magnetic flux of variable amplitude, at least a first and a second magnetic circuit being provided for guiding the magnetic flux generated by the first excitation part, the reluctance of the first and of the second magnetic circuit being controllable by means of the position of the movable member, and the second excitation part being included in the second magnetic circuit.
DESCRIPTION OF PRIOR ART
An electromotive actuating device of the type defined in the opening paragraph is known from the article "Performance Prediction of Laws Relay Actuator", IEE Proceedings, Vol. 137, Pt. B, No. 1, January 1990, pp. 1 to 13, by H. R. Bolton and Y. Shakweh. This known electromotive actuating device is also referred to as a Laws relay and comprises as movable member a soft-magnetic rotor having two rotor pole shoes and as stationary member a stator having four stator pole shoes arranged symmetrically along the circumference. The stator comprises two permanent magnets which generate a constant magnetic flux, as well as two excitation coils by means of which a magnetic flux of variable amplitude can be generated. The four stator pole shoes and the two rotor pole shoes of this known electromotive actuating device have the same circumferential angle. The maximal angle of movement of this electromotive actuating device is as large as the circumferential angle of the stator and rotor pole shoes. The maximum range of movement of this actuating device is limited to values below 90.degree. because both the permanent magnets and the excitation coils require space at the circumference of the air gap.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an electromotive actuating device of the type defined in the opening paragraph by means of which a rotary actuator having a range of movement of more than 90.degree. can be realized.
According to the invention this object is achieved in that the stationary member comprises at least a first pole shoe, a second pole shoe and a third pole shoe, in that the first pole shoe and the third pole shoe form flux guiding elements of the first magnetic circuit, and in that the second pole shoe and the third pole shoe form flux guiding elements of the second magnetic circuit.
The first excitation part is disposed both in the first and in the second magnetic circuit, as a result of which the magnetic flux generated by the first excitation part, which is preferably constant, can be linked via the first and/or the second magnetic circuit. The second excitation part is disposed in the second magnetic circuit only. It is preferably constructed as a an excitation coil, enabling a magnetic flux of variable amplitude to be obtained by variation of the excitation current. The movable member, which is preferably soft-magnetic, is arranged both in the first and in the second magnetic circuit in such a manner that the resistance of the first and of the second magnetic circuit varies in dependence on the position of the movable member. Preferably, the movable member and the stationary member are constructed in such a manner that during movement of the movable member the resistance of the first magnetic circuit and the resistance of the second magnetic circuit vary oppositely, i.e. during a movement of the movable member in a first direction the resistance of the first magnetic circuit increases and the resistance of the second magnetic circuit decreases and during a rotation of the movable member in the opposite second direction the resistance of the first magnetic circuit decreases and the resistance of the second magnetic circuit increases. The electromotive actuating device in accordance with the invention has at least three pole shoes, of which the first pole shoe is arrange
REFERENCES:
patent: 3434082 (1969-03-01), Montagu
patent: 3891922 (1975-06-01), Atzinger
patent: 4462014 (1984-07-01), Montagu
patent: 4845424 (1989-07-01), Gamble
patent: 5243241 (1993-09-01), Wang
"Performance Prediction of Laws's Relay Actuator", by H.R. Bolton et al, IEE Proceedings, vol. 137, PT. B., No. 1, Jan. 1990.
Ackermann Bernd
Houkes Martin
Mullins Burton
Piotrowski Tony E.
U.S. Philips Corporation
LandOfFree
Electromotive adjustable drive does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electromotive adjustable drive, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electromotive adjustable drive will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2067954