JPH0645699Y2 - Spindle device for magnetic bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a spindle device using a magnetic bearing.

[Conventional technology]

FIG. 2 shows the internal structure of a spindle device using a conventional magnetic bearing.

This spindle device has a structure in which a spindle 2 inserted in a shaft box 1 is rotatably supported by a radial magnetic bearing 3 and the spindle 2 is driven to rotate by a drive motor 4. Thrust magnetic bearings 5 and 6 provided at the rear end of the thrust magnetic bearings 5 and 6 provided at intervals in the front-rear direction face each other, and are attached to and detached from the rear end of the spindle 2 between the magnetic coils 7 and 7 of the thrust magnetic bearings 5 and 6. The axial movement of the spindle 2 is controlled by interposing a freely mounted thrust rotor 8. This thrust rotor 8 has a nut 9 screwed from the rear end of the spindle 2.
It is fixed to the spindle 2 by.

Further, a spindle device using a magnetic bearing needs to include a touchdown bearing for supporting the spindle when the spindle is not supported by the magnetic bearing such as when the spindle is stopped. For the purpose of shortening the length as short as possible and improving the dangerous speed, it is desirable to mount it as compact as possible inside the axle box. Therefore, in the conventional structure, the touchdown bearings 10 and 11 formed of ball bearings are attached to the inner peripheral surface of the front thrust magnetic bearing 5 and the tip of the shaft box 1, respectively. The inner diameter surfaces of the touchdown bearings 10 and 11 are opposed to the outer peripheral surface of the spindle 2 with a required radial clearance a in a state in which the spindle 2 is levitationally supported. A required axial clearance b is maintained between the front and rear surfaces of 11 and the thrust rotor 8 and the step portion 2a of the spindle.

In the figure, 12 is a radial direction position sensor, 13 is a thrust direction position sensor, and at the rear end of the spindle 2,
Support plate 14 that is the target of thrust direction position sensor 13
Is installed.

[Problems to be solved by the device]

In the magnetic bearing spindle device as described above, the spindle 2 and the touchdown bearings 10 and 11 come into contact with each other when the levitation control is disabled due to a power failure or at every stop.
The bearings 10, 11 are susceptible to damage and need to be replaced relatively often. However, in the above structure, although the front touchdown bearing 10 can be easily replaced,
In order to replace the rear touchdown bearing 11, it is necessary to first remove the rear thrust magnetic bearing 6 from the shaft box 1, then remove the nut 9 and thrust rotor 8, and further remove the front thrust magnetic bearing 5. However, there is a drawback that the replacement work takes a lot of time and labor.

On the other hand, if the outer peripheral surface of the spindle 2 is damaged, the entire spindle must be replaced, which results in an extremely high repair cost.

The present invention solves the above-mentioned drawbacks of the conventional structure, facilitates replacement of the touchdown bearing without increasing the total length of the spindle, and provides a spindle device that can easily manage the touchdown clearance. The purpose is to do.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention has a thrust rotor attached to the rear end of a spindle which is rotatably supported by a radial magnetic bearing in a shaft box. In a spindle device of a magnetic bearing, in which a thrust magnetic bearing facing each other is attached, and a touchdown bearing for supporting the spindle when the magnetic bearing is not controlled is attached to the front and rear inside the shaft box, a thrust rotor and a thrust rotor are provided at the rear end of the spindle. A small-diameter insertion part into which the cylindrical sleeve is detachably inserted is provided, and a screw member for fixing the thrust rotor by pressing the cylindrical sleeve against the thrust rotor is attached to the end of this insertion part, and the thrust is attached to the front end of the cylindrical sleeve. A flange that abuts the rotor is provided to allow the rear thrust magnetic bearing to move in the front-rear direction, and the inner surface of the rear thrust magnetic bearing has a rear tap. Install a down bearing and provide a radial touchdown clearance between the rear touchdown bearing and the outer diameter surface of the cylindrical sleeve, and between the rear touchdown bearing and the cylindrical sleeve flange and the rear touchdown bearing. A structure is provided in which a thrust-down touchdown gap is provided between the cylindrical sleeve and the surface of the screw member that is in contact with the cylindrical sleeve.

〔Example〕

 An embodiment of the present invention will be described below with reference to FIG.

Similar to the conventional structure shown in FIG. 2, the spindle device of the embodiment is provided with the radial magnetic bearing 3 and the drive motor 4 on the front side inside the shaft box 1, and the magnetic coils 7, 7 at the rear end of the shaft box 1. The thrust magnetic bearings 5 and 6 are attached.

The thrust magnetic bearing 6 on the rear side of the thrust magnetic bearings 5 and 6 is mounted inside the shaft box 1 so as to be movable in the front-rear direction, and is fixed by a fixing means (not shown) as shown in FIG. Thrust rotor 8 between
Is properly fixed at a predetermined position where a gap is inserted.

In the space 6a on the inner peripheral surface of the rear thrust magnetic bearing 6, a touchdown bearing 11 having two ball bearings for vacuum arranged in parallel is detachably fitted. The touchdown bearing 11 is a bearing ring. It is locked by 15

On the other hand, at the rear end of the spindle 2, a rotor mounting portion 2b as an insertion portion for the thrust rotor and the cylindrical sleeve and a small diameter portion 2c are formed via a step portion 2a.
The thrust rotor 8 is removably inserted in the. Further, the fixing means 16 is attached to the rear portion of the thrust rotor 8. This fixing means 16 is a small diameter part of the spindle 2.
It is composed of a cylindrical sleeve 17 that is inserted into 2c without any play, and a screw member 18 that is screwed into the rear end of the spindle 2. A flange 19 is provided at the tip of the cylindrical sleeve 17.
The screw member 18 is composed of a screw shaft 20 and a receiving plate 21, and when the screw member 18 is screwed into the spindle 2, the sleeve 18 presses the thrust rotor 8 against the step portion 2a of the spindle 2 and the thrust rotor 8 and the spindle 2 are integrally fixed.

The dimension of the outer peripheral surface of the cylindrical sleeve 17 is set in a required radial direction with respect to the inner peripheral surfaces of the touchdown bearings 10 and 11 with the magnetic bearings 3, 5 and 6 controlling the spindle 2 to float as shown in FIG. The sleeve 19 is formed to have a clearance a, and the length of the sleeve 17 from the flange 19 to the rear end is
The bearing 11 and the receiving plate 21 of the screw member 18 and the bearing 11 are formed so that a required axial touchdown gap b can be formed.

In the assembled state, the receiving plate 21 of the screw member 18 faces the thrust position sensor 13 attached to the rear lid 23 of the shaft box 1. The receiving plate 21 also serves as a target of the position sensor 13. Function.

To assemble the thrust rotor 8, first, with the rear thrust magnetic bearing 6 removed from the shaft box 1, insert the thrust rotor 8 into the rotor mounting portion 2b of the spindle 2, and then insert the sleeve 17 into the small diameter portion 2c. Then, the rear thrust magnetic bearing 6 is attached to the axle box 1. After that, the screw member 18 is screwed into the spindle 2 and the thrust rotor 8 and the sleeve are
17 is fixed, and then the rear lid 23 is attached to the axle box 1.

In the above structure, when the magnetic bearing is out of control or the spindle 2 is stopped, the sleeve 17 and the touchdown bearing are
11 contacts and supports the rear end of the spindle 2. For this reason, it is the sleeve 17 and touchdown bearing 11 that will be damaged.
Only the spindle 2 is not damaged.

The worn sleeve 17 and the touch-down bearing 11 can be easily replaced by removing the screw member 18 from the spindle 2 and the rear thrust magnetic bearing 6 from the axle box 1 in the reverse order of the above-described assembly sequence. it can.

Further, since the touchdown clearances a and b for the touchdown bearing 11 change when the outer diameter dimension and the length dimension of the sleeve 17 are changed, the clearances a and b are appropriately controlled by adjusting the dimension of the sleeve 17. can do. In this case, the sleeve 17 is smaller than the spindle 2,
Since it is easy to set the dimensions, the clearances a and b can be controlled more accurately and at lower cost than the conventional structure.

In addition, if several kinds of sleeves 17 with different dimensions are prepared, it is possible to select and use the sleeve 17 corresponding to the change in the diameter of the spindle 2 when the diameter of the spindle 2 changes.

In the above structure, the rear touchdown bearing 11 is moved from the front thrust magnetic bearing 5 to the rear thrust magnetic bearing 6 as compared with the conventional structure, and the cylindrical sleeve 17 and the bearing 11 are provided in the mounting space of the nut 9. The overall length of the device can be made equal to or shorter than that of the conventional structure, and can be made compact.

[Effect of device]

As described above, according to the present invention, the fixing means of the thrust rotor is composed of the cylindrical sleeve detachably attached to the spindle and the screw member, and the touchdown bearing attached to the rear thrust magnetic bearing is brought into contact with the cylindrical sleeve. Since the spindle is supported by doing so, it does not damage the spindle as in the past and replaces the worn sleeve and touchdown bearing, and the thrust rotor simply by removing the rear thrust magnetic bearing and the screw member. Since it can be easily performed, it is possible to improve the assemblability and reduce the cost.

Also, the touchdown clearance in the radial and thrust directions can be adjusted by adjusting the outer diameter and length of the cylindrical sleeve, so even if the replaced thrust rotor or touchdown bearing has variations in size. By controlling only the dimensions of the cylindrical sleeve, the touchdown gap can be inserted with appropriate accuracy, and there is an advantage that the gap can be concentrated and easily managed.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment according to the present invention, and FIG. 2 is a vertical sectional front view of a conventional structure. 1 ... Shaft box, 2 ... Spindle, 3 ... Radial magnetic bearing, 5, 6 ... Thrust magnetic bearing, 7 ... Magnetic coil, 8 ... Thrust rotor, 10, 11 ... Touchdown bearing, 16 ...... Fixing means, 17 …… Cylinder sleeve, 18 …… Screw member, a, b …… Touchdown clearance.

Claims (1)

[Scope of utility model registration request] 1. A thrust magnetic bearing, wherein a thrust rotor is attached to the rear end of a spindle rotatably supported by a radial magnetic bearing in a shaft box and the front and rear surfaces of the thrust rotor are opposed to the rear end of the shaft box. In the spindle device of the magnetic bearing, in which the touchdown bearing that supports the spindle when the magnetic bearing is not controlled is attached to the front and rear of the inside of the shaft box, the thrust rotor and the cylindrical sleeve are detachably inserted at the rear end of the spindle. A small diameter insertion part is provided, a screw member for pressing the cylindrical sleeve against the thrust rotor to fix the thrust rotor is attached to the end part of the insertion part, and a flange that abuts the thrust rotor is provided at the front end of the cylindrical sleeve. , The rear thrust magnetic bearing is movable in the front-rear direction, and the rear touchdown bearing is attached to the inner peripheral surface of the rear thrust magnetic bearing. A radial touchdown gap is provided between the side touchdown bearing and the outer diameter surface of the cylindrical sleeve, and the screw that abuts the rear touchdown bearing and the cylindrical sleeve and between the rear touchdown bearing and the cylindrical sleeve. A spindle device for a magnetic bearing, characterized in that a touchdown gap in the thrust direction is provided between the member and the surface of the member.