JPH04271287A - Magnetic levitation actuator - Google Patents

Abstract

PURPOSE:To provide a magnetic levitation actuator having small size and producing high drive force. CONSTITUTION:A magnetic levitation actuator comprises a rotor 2 disposed rotatably and movably in the axial direction on the inside of cylindrical wall sections 1b, 1c, magnetic bearings 6, 7 disposed fixedly to the cylindrical wall section 1b and holding the rotor 2 in the radial direction, and a magnetic coupling 10 having a drive section 11 disposed rotatably and movably in the axial direction around the cylindrical wall section 1c and transmitting the rotary force and the axial holding force to the rotor 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetically levitated actuator that drives a rotor disposed inside a cylindrical wall of a vacuum shield or the like from outside the wall in a non-contact manner using magnetism in the rotational and axial directions.

0002

[Prior Art] As an actuator for magnetically driving a rotor in a non-contact manner, a movable housing is provided outside a cylindrical wall so as to be movable in the axial direction. It is known that a rotor is provided with a magnetic bearing that is held in the axial direction and a drive section of a magnetic joint that transmits rotational force to the rotor.

In this actuator, the rotor is rotated by rotating the driving portion of the magnetic joint, and by moving the housing in the axial direction, the rotor is moved in the axial direction by the holding force of the magnetic bearing.

0004

However, when such an actuator as described above is used to drive a rotor disposed inside a cylindrical wall, the following problems occur.

[0005] The air gap of magnetic bearings is generally small;
Since the magnetic bearing moves along the cylindrical wall, the cylindrical wall must be made thin and processed with high precision, which poses problems in terms of mass productivity and quality.

[0006] For this reason, in practice, the air gap of the magnetic bearing must be increased, but this reduces the holding force of the magnetic bearing, especially the holding force in the axial direction. The driving force in the axial direction becomes very small. Therefore, in order to obtain sufficient driving force, it is necessary to increase the control current, resulting in an increase in the size of the magnetic bearing.

[0007] The purpose of the present invention is to solve the above problems,
The object of the present invention is to provide a magnetic levitation actuator that is small and has a large driving force.

[0008]

[Means for Solving the Problems] A magnetically levitated actuator according to the present invention includes a rotor disposed inside a cylindrical wall so as to be rotatable and movable in the axial direction, and a rotor fixedly provided on the cylindrical wall. A magnetic bearing for radial retention and a magnetic coupling for rotational and axial movement with a drive disposed around the cylindrical wall and transmitting rotational and axial drive forces to the rotor. It is something.

[0009]

[Operation] Since the magnetic bearing that holds the rotor in the radial direction is fixedly provided on the cylindrical wall, the air gap between the rotor and the magnetic bearing can be reduced. Therefore, even if the magnetic bearing is small, sufficient holding force can be obtained.

[0010] It is the driving part of the magnetic joint that moves along the cylindrical wall, and the magnetic joint can obtain sufficient driving force even with a large air gap, so there is no need to increase the machining accuracy of the cylindrical wall. Moreover, there is no need to make the magnetic coupling itself large.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the upper and lower sides of the drawings are referred to as the upper and lower sides, and the rotation direction is the direction seen from above. Regarding the rotation direction, clockwise direction is defined as right direction, and counterclockwise direction is defined as left direction.

The magnetic levitation actuator shown in FIG. 1 has a first rotor (2) and a second rotor (3) placed in a vacuum atmosphere (V) inside a vacuum shield (1). The atmosphere (A) is driven from within.

The shield (1) has an upper cylindrical wall portion (1b) extending vertically downward from a hole formed in the horizontal wall portion (1a), and a lower bottomed cylindrical wall portion (1b) extending vertically downward from the lower end of the upper cylindrical wall portion (1b). 1c), and the two rotors (2) and (3) are fitted in a vacuum atmosphere (V) within the upper and lower cylindrical walls (1b and 1c) so that they can rotate and move in the vertical direction. ing. The first rotor (2) has a vertical cylindrical shape and is fitted into the cylindrical wall portions (1b) and (1c) with a slight gap. The second rotor (3) has a vertical shaft shape and is inserted into the center of the first rotor (2) so that both upper and lower ends protrude from the first rotor (2). The second rotor (3) has two upper and lower bearings (4).
(5), it is supported so that it cannot move vertically but can rotate relative to the first rotor (2). In addition, a second rotor (2) protrudes downward from the lower end of the first rotor (2).
A short cylindrical large diameter portion (3a) having an outer diameter approximately equal to that of the first rotor (2) is formed at the lower end of the rotor (3).

The first rotor (2) of the upper cylindrical wall (1b)
Two upper and lower magnetic bearings (6) and (7) are fixed to the surrounding area. These magnetic bearings (6) and (7) are publicly known, and for example, electromagnets (6) are installed at four locations in the circumferential direction.
a) (6b) (7a) (7b), and the first rotor (2
) is maintained primarily in the radial direction.

A movable unit (8) is provided around the lower cylindrical wall (1c).

The movable unit (8) includes a movable housing (9) and a first
A drive unit (first drive unit) (11) for the magnetic coupling (10) and a drive unit (second drive unit) (13) for the second magnetic coupling (12) provided at the bottom of the housing (9). There is.

The housing (9) is moved in the vertical direction along the lower cylindrical wall (1c) by suitable means (not shown).

[0018] The first drive section (11) and the second drive section (1
3) has a ring shape coaxial with the cylindrical wall part (1c), and has bearings (14), (15), and (16) so that it can rotate around the axis.
) (17) to the housing (9). Although not shown, the first drive section (11) is driven by the second drive section (11) by a first motor provided in the housing (9).
13) are rotated independently of each other by a second motor provided in the housing (9).

The driving portion (11) of the first magnetic coupling (10) faces the lower outer circumferential surface of the first rotor (2) with the lower cylindrical wall portion (1c) in between, and the first rotor (2) A driven portion of the first magnetic coupling (10) is formed on the lower outer circumferential surface of the magnetic joint (10).

Details of the first magnetic coupling (10) are shown in FIGS. 2-4.

[0021] First drive section (11) and first rotor (2)
Permanent magnet devices (18a), (18b), (18c), and (18d) are provided at four locations that equally divide the opposing peripheral surfaces of the lower part in the circumferential direction.

[0022] Each permanent magnet device (18a) to (18d)
is an upper permanent magnet (19a) extending in the circumferential direction fixed to the inner circumferential surface of the first drive part (11) at intervals vertically.
(19b) (19c) (19d) and the lower permanent magnet (
20a) (20b) (20c) (20d), as well as left permanent magnets (21a) (2) extending in the vertical direction fixed to the outer peripheral surface of the first rotor (2) at intervals in the circumferential direction.
1b) (21c) (21d) and the right permanent magnet (22
a) (22b) (22c) (22d). Permanent magnets (19a) to (19d) above and below the first drive unit (11)
) (20a) to (20d) have magnetic poles at both left and right ends,
Upper and lower permanent magnets (19a) ~ (19d) (20a) ~
In (20d), the left and right polarities are reversed. The left and right permanent magnets (21a) to (21d) of the first rotor (2)
) (22a) to (22d) have magnetic poles at both the upper and lower ends,
Left and right permanent magnets (21a) ~ (21d) (22a) ~
In (22d), the upper and lower polarities are reversed. The upper end magnetic poles of the left permanent magnets (21a) to (21d) are the left end magnetic poles of the upper permanent magnets (19a) to (19d), and the lower end magnetic poles of the left permanent magnets (21a) to (21d) are the lower permanent magnets. At the leftmost magnetic pole of (20a) to (20d), the right permanent magnet (22a) to (22d)
The magnetic poles at the upper end of the upper permanent magnets (19a) to (19d)
The right-hand permanent magnet (22a) ~ (22
d) The magnetic pole at the lower end of the lower permanent magnet (20a) ~ (2
0d), and the polarities of the two mutually opposing magnetic poles are opposite. and,
The magnetic pole arrangement of the first permanent magnet device (18a) and the third permanent magnet device (18c) located symmetrically with this one is the same, and the remaining second permanent magnet device (18b) and the third permanent magnet device (18c) located symmetrically with this device have the same magnetic pole arrangement. The arrangement of the magnetic poles of the four permanent magnet devices (18d) is the same. For this reason, each permanent magnet device (18a)
~(18d) includes the radial direction of the first rotor (2),
A closed magnetic path is formed that extends in the axial and circumferential directions.

To explain in more detail, the first and third
In the permanent magnet devices (18a) (18c), the left ends of the upper permanent magnets (19a) (19c) are N poles and the right ends are S poles, and the left ends of lower permanent magnets (20a) (20c) are S poles and the right ends are N poles.
The upper ends of the left permanent magnets (21a) (21c) are S poles and the lower ends are N poles, and the upper ends of right permanent magnets (22a) (22c) are N poles and the lower ends are S poles. A closed magnetic path is formed that extends in the radial, axial, and circumferential directions of the first rotor (2) as shown in FIG.

Second and fourth permanent magnet devices (18b) (
18d), conversely, the upper permanent magnet (19b) (19d
), the left end is the S pole and the right end is the N pole, the lower permanent magnet (20b)
The left end of (20d) is the N pole, the right end is the S pole, and the left permanent magnet (
The upper ends of 21b) (21d) are N poles and the lower ends are S poles, and the upper ends of right permanent magnets (22b) (22d) are S poles and the lower ends are N poles, and in the radial direction of the first rotor (2), A closed magnetic path is formed that extends in the axial and circumferential directions.

Four permanent magnet devices (18a) to (18
d) Since a closed magnetic path is formed in the first drive part (1
1) and the first rotor (2). Since this magnetic path extends in the radial direction, axial direction, and circumferential direction of the first rotor (2), the rotational force and the axial direction are transmitted from the first drive section (11) to the first rotor (2). driving force is transmitted. Then, by rotating the first drive section (11),
The first rotor (2) also rotates, and by moving the first drive section (11) in the axial direction, the first rotor (2) also moves in the axial direction.

[0026] The drive part (13) of the second magnetic coupling (12) faces the outer peripheral surface of the large diameter part (3a) of the second rotor (3) with the lower cylindrical wall part (1c) in between. Large diameter part (3
A driven portion of the second magnetic joint (12) is formed on the outer peripheral surface of a). The second magnetic joint (12) is, for example,
This is a known device as described in Japanese Patent No. 150,650, etc., and the rotational force of the second drive section (13) is transmitted to the second rotor (3).

When the movable housing (9) moves up and down, the drive parts (11) of the two magnetic joints (10) and (12)
(13) also moves up and down, and the two rotors (2) and (3) are moved up and down together by the holding force in the axial direction of the first magnetic coupling (10).

[0028] The first magnetic joint (10) is connected by the first motor.
When the drive unit (11) of the rotor is rotated, its rotational force is transmitted to the first rotor (2), and the first rotor (2) is rotated independently of the second rotor (3). Similarly, the drive section (13) of the second magnetic joint (12) is driven by the second motor.
) is rotated, the rotational force is transmitted to the second rotor (3), and the second rotor (3) is rotated independently of the first rotor (2).

The invention also applies to magnetic levitation actuators in which only one rotor is driven rotationally and axially. In this case, in the above embodiment, the cylindrical wall part (1
b) Only the first rotor (2) is provided in (1c), and the movable housing (9) has a first magnetic coupling (10) for driving the first rotor (2) in the rotational and axial directions.
Only one drive unit (11) is provided.

[0030]

According to the magnetically levitated actuator of the present invention, as described above, the air gap between the rotor and the magnetic bearing that holds the rotor in the radial direction can be reduced, even if the magnetic bearing is small. , sufficient holding force can be obtained. Further, since the rotational force and the axial driving force are transmitted to the rotor by the magnetic joint, there is no need to increase the machining accuracy of the cylindrical wall so much, and the magnetic joint itself does not need to be large.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a magnetic levitation actuator showing an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing a first magnetic joint of the magnetic levitation actuator of FIG. 1;

FIG. 3 is a perspective view showing the arrangement of permanent magnets in the drive section of the first magnetic joint in FIG. 2;

FIG. 4 is a perspective view showing the arrangement of permanent magnets of the first permanent magnet device of the first magnetic joint in FIG. 2;

[Explanation of symbols]

Claims (1)

[Claims] 1. A rotor disposed inside a cylindrical wall so as to be able to rotate and move in the axial direction, a magnetic bearing that is fixedly provided on the cylindrical wall and holds the rotor in the radial direction, and a rotor that can rotate and move in the axial direction. A magnetic levitation actuator in which a drive part is arranged around a cylindrical wall for directional movement and includes a magnetic coupling for transmitting rotational force and axial drive force to a rotor.