JP2511944Y2 - Magnetic bearing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic bearing device incorporating a high frequency motor.

2. Description of the Related Art In a magnetic bearing device, usually, a rotary shaft (spindle) is provided with a motor rotor part of a high frequency motor and a rotor disk part of an axial magnetic bearing, and a motor stator part of the high frequency motor and a rotor disk are provided around the rotary shaft. Of the axial magnetic bearing that attracts the part to control the axial position of the rotary shaft, the electromagnet of the radial magnetic bearing that attracts the rotary shaft to control the radial position of the rotary shaft, and the radial direction of the rotary shaft. A radial displacement sensor that detects a displacement is provided, and an axial displacement sensor that detects a displacement of the rotating shaft in the axial direction is provided at one end of the rotating shaft.

In the conventional magnetic bearing device, the motor rotor portion and the motor stator portion of the high frequency motor are arranged substantially in the center with respect to the axial direction of the rotary shaft, and the electromagnets and the radial displacement sensors of the radial magnetic bearing are arranged on both sides of the high frequency motor. The rotor disk portion of the axial magnetic bearing and the electromagnet are arranged at a portion near one end of the rotary shaft.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In a conventional magnetic bearing device having a built-in high-frequency motor as described above, the magnetic flux leaking from the motor increases as the rotation increases, and the magnetic flux passes through the detection coil of the internal displacement sensor. Therefore, noise is generated in the signal of the displacement sensor. For this reason, abnormal vibration may occur, which eventually leads to an uncontrollable state.

An object of the present invention is to provide a magnetic bearing device that solves the above problems.

Means for Solving the Problems A magnetic bearing device according to the present invention is provided with a motor rotor part of a high-frequency motor and a rotor disk part of an axial magnetic bearing on a rotary shaft, and a motor stator part and a rotor of the high-frequency motor around the rotary shaft. Axial magnetic bearing electromagnet that attracts the disk to control the axial position of the rotary shaft, radial magnetic bearing electromagnet that attracts the rotary shaft to control the radial position of the rotary shaft, and radial direction of the rotary shaft In a magnetic bearing device equipped with a radial displacement sensor for detecting the displacement of the high frequency motor, it is fixed to the rotor disk part and the case that form the axial magnetic bearing that is installed on the rotary shaft in order on both sides in the axial direction of the high frequency motor. A high-frequency motor is installed by arranging electromagnets that are provided to form an axial magnetic bearing. Adapted to enclose, and is characterized in that the electromagnets and the radial displacement sensors of the radial magnetic bearing axially outwardly of each of these axial magnetic bearing electromagnets are disposed.

Action The rotor disk and the electromagnet of the axial magnetic bearings, which are sequentially arranged on both sides in the axial direction so as to surround the high-frequency motor, exert a shielding effect against the magnetic flux leaking from the motor, and the magnetic flux leaks from the axial magnetic bearing. Almost no outside of the part in the axial direction, that is, on the side opposite to the motor. Therefore, the influence of the leakage magnetic flux on the displacement sensor arranged further axially outside the axial magnetic bearing is reduced. Further, since it is not necessary to add a new shield mechanism only by changing the arrangement of the axial magnetic bearings originally required for the magnetic bearing device, the rotating shaft hardly becomes long.

Examples Hereinafter, with reference to the drawings. An embodiment of this invention will be described. In the following description, the left and right sides of the drawing will be referred to as the left and right.

The magnetic bearing device comprises a rotating shaft (1) extending to the left and right. Further, the magnetic bearing device has a built-in high frequency motor (2), which allows the shaft (1) to rotate at high speed in a fixed case (not shown) in a non-contact state.

A motor rotor part (3) of the high-frequency motor (2) is provided at the center of the shaft (1) in the length direction (left-right direction), and a motor stator part (4) of the high-frequency motor (2) is provided around the motor rotor part (3). ing. Rotor disk parts (7) and (8) of axial magnetic bearings (5) and (6) are provided on the left and right shafts (1) of the motor (2), and the shafts of the rotor disk parts (7) and (8) are further provided. Electromagnets (9) and (10) of axial magnetic bearings (5) and (6) are arranged on the outside in the direction, that is, on the side opposite to the motor, to control the axial position of the shaft (1) by attracting them. The motor stator portion (4) and the electromagnets (9) and (10) of the axial magnetic bearings (5) and (6) are fixedly provided in the case and are connected by a suitable magnetic body (11). Then, the rotor disk portions (7) (8) of the axial magnetic bearings (5) (6)
The motor (2) is surrounded by the electromagnets (9) and (10) and the magnetic body (11).

Electromagnets (9) (1) for axial magnetic bearings (5) (6)
Electromagnets of radial magnetic bearings (12) and (13) that control the radial position of the shaft (1) by attracting the shaft (1) to the outside of the shaft (1) in the axial direction, that is, around the shaft (1) on the side opposite to the motor. (1
4) (15) are placed, and further on the outside in the axial direction,
Radial displacement sensors (16) (17) for detecting the radial displacement of the shaft (1) are arranged. The electromagnets (14) (15) and the radial displacement sensors (16) (17) of the radial magnetic bearings (12) (13) are fixedly provided in the case.

Although illustration is omitted, an axial displacement sensor for detecting the axial displacement of the shaft (1) is provided at an appropriate position of the case facing one end face of the shaft (1).

With respect to the magnetic flux leaking from the motor (2), the rotor disk parts (7) and (8) and the electromagnets (9) and (10) of the axial magnetic bearings (5) and (6) arranged on both the left and right sides of the motor (2) The shielding effect is exerted, and the leakage magnetic flux hardly appears axially outside of the axial magnetic bearings (5) and (6), that is, on the side opposite to the motor. The motor (2)
If the leakage magnetic flux in the radial direction of the
By surrounding the motor (2) with and the axial magnetic bearings (5) and (6), leakage magnetic flux does not appear outside the magnetic body (11). Therefore, the axial magnetic bearing (5)
The influence of the leakage magnetic flux on the displacement sensors (16) and (17) arranged further axially outside (6), that is, on the side opposite to the motor, is reduced. Further, since the shield effect is exerted by the axial magnetic bearings (5) and (6) originally required for the magnetic bearing device, it is not necessary to add a new shield mechanism, and the rotating shaft (1) is almost lengthened. No need.

Effect of the Invention According to the magnetic bearing device of the present invention, as described above, the rotating shaft is made substantially longer by the rotor disk portion and the electromagnet of the axial magnetic bearings arranged on both sides in the axial direction so as to surround the high frequency motor. Instead, the magnetic flux leakage from the motor can be effectively shielded to reduce the influence of the leakage magnetic flux on the displacement sensor located axially outside of the axial magnetic bearing, that is, on the side opposite to the motor. Further, it becomes easy to increase the output of the high frequency motor and improve the bearing rigidity.

[Brief description of drawings]

The drawing is a schematic vertical sectional view of a magnetic bearing device showing an embodiment of the present invention. (1) ... Rotary axis, (2) ... High frequency motor, (3) ...
… Motor rotor, (4) …… Motor stator,
(5) (6) ... Axial magnetic bearing, (7) (8) ...
… Rotor disk part (9) (10) …… electromagnet, (12)
(13) …… Radial magnetic bearing, (14) (15) …… Electromagnet, (16) (17) …… Radial displacement sensor.

Claims (1)

(57) [Scope of utility model registration request] 1. A motor rotor part of a high frequency motor and a rotor disk part of an axial magnetic bearing are provided on a rotary shaft, and the motor stator part and rotor disk part of the high frequency motor are sucked around the rotary shaft to axially rotate the rotary shaft. The axial magnetic bearing electromagnet that controls the axial position, the radial magnetic bearing electromagnet that attracts the rotary shaft to control the radial position of the rotary shaft, and the radial displacement sensor that detects the radial displacement of the rotary shaft are provided. In the conventional magnetic bearing device, the rotor disk portion that is provided on the rotating shaft to form the axial magnetic bearing and the electromagnet that is fixedly provided to the case to form the axial magnetic bearing are provided on both sides in the axial direction of the high frequency motor. These axial magnetic shafts are arranged to surround the high frequency motor. A magnetic bearing device, wherein an electromagnet of a radial magnetic bearing and a radial displacement sensor are arranged outside each of the receiving electromagnets in the axial direction.