High-efficiency rotating coil torque motor

Details High-efficiency rotating coil torque motor High-efficiency rotating coil torque motor

1995-12-01

2001-11-27

Dougherty, Thomas M. (Department: 2102)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S154090, C310S261100

Reexamination Certificate

active

06323575

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a torque motor and, more particularly, to a torque motor having an optimized stationary magnetic field.
A mechanical actuator is a device that controllably produces a mechanical movement. The mechanical actuator is typically connected to another device which requires such a movement for its proper operation. Mechanical actuators can be designed to produce linear, rotational, or other types of movements, as required, and the present invention deals with a rotational actuator or torque motor.
One type of torque motor includes a set of electromagnet rotor coils affixed to a stationary annular support ring in a symmetric configuration. A set of corresponding permanent magnets is affixed to a rotationally movable shaft lying within the support ring, with the permanent magnets in a generally facing but angularly displaced relationship to the electromagnet rotor coils. A ferromagnetic stationary flux shield overlies the annular support ring.
This conventional torque motor is operable, but has limitations resulting from its design. The inventor has recognized that the presence of the flux shield reduces the available torque of the motor due to induced magnetic coupling. Moreover, it is difficult to optimize the performance of the torque motor within the weight, response, and space constraints of the torque motor.
There is a need for an improved approach to the design of a torque motor. The present invention fulfills this need, and further provides related advantages.
SUMMARY OF THE INVENTION
The present invention provides a torque motor with improved torque and response characteristics, within the same size envelope as prior torque motors. Alternatively, the torque motor can be built smaller and lighter than conventional torque motors, but with the same torque performance. The torque motor is also more efficient than conventional torque motors, leading to lower heat production in service. The preferred torque motor of the invention achieves substantially linear performance over about ±7.5° (about 15° total) of rotational movement, which is sufficient for many practical applications of interest.
In accordance with the invention, a torque motor comprises an annular, cylindrically symmetric, stationary inner support ring, and at least two inner permanent magnets affixed to the inner support ring. There is further an annular, cylindrically symmetric, stationary outer support ring overlying the inner support ring, and at least two outer permanent magnets affixed to the outer support ring. The torque motor has an annular, cylindrically symmetric, rotationally movable rotor body lying between the inner support ring and the outer support ring, and at least one electromagnet rotor coil affixed to the movable rotor body ring.
In a preferred embodiment, a torque motor comprises an annular, cylindrically symmetric, stationary inner support ring having an outer surface, and a plurality of inner permanent magnets affixed to the outer surface of the inner support ring. There is an annular, cylindrically symmetric, stationary outer support ring overlying the inner support ring and having an inner surface, and a plurality of outer permanent magnets affixed to the inner surface of the outer support ring. The torque motor further includes an annular, cylindrically symmetric, rotationally movable rotor body ring lying between the inner support ring and the outer support ring. The movable rotor body ring has a plurality of openings therethrough, and a plurality of electromagnet rotor coils affixed in the openings on the movable rotor body ring. There are preferably six corresponding inner permanent magnets, twelve outer permanent magnets, and six electromagnet rotor coils set in generally facing, but angularly offset positions, each arranged in a pattern of six-fold symmetry on their respective support rings.
The torque motor of the invention achieves a flux focusing effect through the facing relation of the inner and outer permanent magnets. The electromagnet rotor coils on the movable rotor body ring consequently react with a higher magnetic field than would otherwise be the case, resulting in a higher torque output of the motor without an increase in the envelope size of the torque motor.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.


REFERENCES:
patent: 3602749 (1971-08-01), Esters
patent: 4041512 (1977-08-01), Iwata et al.
patent: 4378146 (1983-03-01), Suzuki et al.
patent: 4460253 (1984-07-01), Kawai et al.
patent: 5038063 (1991-08-01), Graber et al.
patent: 5081388 (1992-01-01), Chen
patent: 338518 (1959-05-01), None

Affiliated with

Also associated with

Rating

High-efficiency rotating coil torque motor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with High-efficiency rotating coil torque motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-efficiency rotating coil torque motor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2593199