Rotary driving apparatus

• US 4,577,832 A
• Filed: 02/21/1985
• Issued: 03/25/1986
• Est. Priority Date: 02/24/1984
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sogabe, Ichita
• Primary Examiner(s): Scott, Samuel
• Assistant Examiner(s): KAMEN, NOAH P
• Application Number:
  US06/704,031
• Time in Patent Office: 397 Days
• Field of Search: 251/129, 251/133, 251/134, 251/137, 251/65, 335/229, 335/230, 335/234, 137/625.65
• US Class Current: 251/129.11
• CPC Class Codes: H01F 7/145 Rotary electromagnets with variable gap with fixed gap or torque motors H02K26/00

Abstract

A rotary driving apparatus having a tubular casing in which a stator having a pair of circumferentially spaced pole portions and a rotor having a pair of radially spaced pole portions are arranged. One of the rotor and the stator is made of a permanent magnet. The apparatus has a coil for magnetizing the other one of the rotor and the stator. The rotor extends out of the inner periphery of the stator so that rotation of a limited angle of the rotor is allowed, the direction of which is changed in accordance with the direction of the electric current applied to the coil.

Claims

1. A rotary drive apparatus comprising:

an axially elongated casing having a circular cross-sectional shape;

a rotor rotatably arranged in said casing about an axis of the casing, said rotor being a permanent magnet;

a first stator fixedly arranged in the casing and made of magnetic material, said stator having a connection portion and a pair of circumferentially spaced pole portions extending from the connection portion, each pole portion defining a pair of spaced side surfaces extending substantially radially and inner and outer circumferential surfaces connecting said side surfaces, said outer circumferential surface forming, in cross section, an arc shape corresponding to the inner periphery of the casing, allowing the outer circumferential surface to be located closely adjacent to the inner surface of the circular cross-sectional shape casing;

said rotor having a pair of radially spaced and oppositely magnetized pole portions, each of which defines a pair of spaced side surfaces extending substantially radially outward of the inner surfaces of the pole portions of the stator, allowing rotation of the rotor to a limited angle between a position where at least one pair of opposing side surfaces of the stator pole portions and the rotor pole portions are engaged with each other and another position where at least another one pair of the opposing surfaces of the stator pole portions and the rotor pole portions are engaged with each other;

coil means, arranged on one side of the rotor along the axis of the casing, for magnetizing said first stator so that the pole portions of the stator are oppositely magnetized, whereby a closed loop of magnetic flux, the direction of which is determined in accordance with the direction of an electric current in the coil means, is generated in order to attain the rotational movement of the rotor in a desired direction between said positions.

2. A rotary drive apparatus according to claim 1, further comprising thin layers made of a non-magnetic material arranged between said pairs of opposing side surface of the stator pole portions and the rotor pole portions.

3. A rotary drive apparatus according to claim 2, wherein said layers are fixedly connected to the corresponding side surfaces of the stator pole portions.

4. A rotary drive apparatus according to claim 1, further comprising a second stator made as a magnetic material fixedly arranged in the casing, said second stator having a pair of circumferentially spaced pole portions located between the pole portions of the first stator, said pole portions of the second stator defining inner surfaces located radially outward of the rotor so as to permit the rotor to rotate between the positions, and second coil means for magnetizing the second stator so that its pole portions are oppositely magnetized, whereby the rotor can have, in addition to said positions, another intermediate position located between said two positions, at which intermediate position the rotor pole portions are respectively located so that they align with the corresponding pole portions of the second stator.

5. A rotary drive apparatus according to claim 1, wherein said pole portions of the stator having the outer circumferential surface having an arc shaped cross-section are integral with respect to the connection portion which is coaxially arranged with respect to the axis of the casing, the coil means being arranged around said connection portion.

6. The rotary drive apparatus according to claim 1, wherein said rotor is adapted for integral connection to a rotary valve which is coaxial with respect to the axis of the rotor for opening a flow passageway when the rotor is in said first position and for closing the flow passageway when the rotor is in said second position.

7. A rotary drive apparatus comprising:

an axially elongated casing;

a rotor rotatably arranged in the casing about an axis of the casing and made from a permanent magnet;

a first stator fixedly arranged in the casing, said stator having a pair of circumferentially spaced pole portions, each of which defines a pair of spaced side surfaces extending substantially radially and an inner circumferential surface connecting said side surfaces;

said rotor having a pair of radially spaced pole portions, each of which defines a pair of spaced side surfaces extending substantially radially outward of the inner surfaces of the pole portions of the stator, allowing rotation of the rotor of a limited angle between a position where at least one pair of opposing side surfaces of the stator pole portions and the rotor pole portions are engaged with each other and another position where at least another one pair of the opposing surfaces of the stator pole portions and the rotor pole portions are engaged with each other;

one of the rotor or the stator being made as a permanent magnet, corresponding pole portions of said one member being oppositely magnetized;

the other one of the rotor and the stator being made of magnetic material;

coil means for magnetizing said other member so that the corresponding pole portions are oppositely magnetized, whereby a closed loop of magnetic flux, the direction of which is determined in accordance with the direction of an electric current in the coil means, is generated in order to attain the rotational movement of the rotor of desired direction between said positions; and

a second stator made as a magnetic material fixedly arranged in the casing, said second stator having a pair of circumferentially spaced pole portions located between the pole portions of the first stator, said pole portions of the second stator defining inner surfaces located radially outward of the rotor so as to permit the rotor to rotate between the positions, and second coil means for magnetizing the second stator so that its pole portions are oppositely magnetized, whereby the rotor can have, in addition to said positions, another intermediate position located between said two positions, at which intermediate position the rotor pole portions are respectively located so that they align with the corresponding pole portions of the second stator.

8. A rotary drive apparatus according to claim 7, further comprising thin layers made of a non-magnetic material arranged between said pairs of opposing side surface of the stator pole portions and the rotor pole portions.

9. A rotary drive apparatus according to claim 8, wherein said layers are fixedly connected to the corresponding side surfaces of the stator pole portions.

10. A rotary drive apparatus according to claim 7, wherein said casing is substantially circularly cylindrical in form.

11. A rotary drive apparatus according to claim 10, wherein the axis of the circular cylindrical casing corresponds to the axis of rotation of the rotor.