JP2000274433A - Protective rolling bearing in magnetic bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a rolling bearing without forming an impression on a raceway track of a bearing by forming an extending flange on an outer peripheral surface or an inner peripheral surface of the bearing, and arranging a jig engaging part in an end part. SOLUTION: When removing a bearing 3, a magnetic bearing device is disassembled to take out a disassembling unit of a bearing 3 state fixed to a stator column 1 by a cover 9 to remove the cover 9 by removing a screw 10 in the arrow A direction. Afterwards, a tip part of a pull-out jig 15 is hooked on a peripheral step part 14 of an end part of a flange 8 to be pulled outward in the shaft direction (the arror B1, B2 direction) together with the bearing 3, and the bearing 3 is removed from the stator column 1. Thus, since this protective rolling bearing is not formed as a structure of directly pulling out an inner race 5 of the bearing 3 by the jig 15 as usual, there is no possibility of generating an impression on a raceway track of the bearing 3, so that a handrance is not caused when reusing the bearing 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective rolling bearing in a magnetic bearing device such as a turbo molecular pump.

[0002]

2. Description of the Related Art In a conventional turbo molecular pump, for example, a plurality of stator blades are provided on an inner peripheral surface of a cylindrical casing, and a plurality of rotor blades are alternately arranged on the outer peripheral surface of the rotor in the axial direction. The rotor is a motor mechanism that acts as a rotor of the motor. In order to cope with the high-speed rotation of the rotor, a magnetic bearing device is used.

In the above magnetic bearing device, when the rotor cannot be controlled in the event of an abnormality such as a power failure, for example, the rotor is brought into contact with the magnetic bearing and the like so as not to damage the rotor. A rolling bearing is provided on the casing side. The operation in which the rotor is stopped by being received by the protective rolling bearing is called touch-down.
As the above-described protective rolling bearing, for example, FIG.
No. -4390) is known. That is, the circumferential step portion 31 of the stator column 30 on the fixed side
One end surface 33a and outer peripheral surface 33b of the outer ring 33 of the rolling bearing 32 are placed in contact with each other, and a cover 35 is mounted on the other end surface 33c so as to clamp the outer ring 33 between the stator columns 30. It is fastened to the column 30 with a screw 36 or the like. Thereby, the entire bearing 32 is firmly fixed to the stator column 30 via the outer ring 33. Further, when the rotor 37 on the rotating side is rotating normally, the inner ring 34 has a gap of, for example, about 0.1 to several mm between the inner ring 34 and the rotor 37. And the rotor 37
Is stopped, the rotor 37 contacts the inner race 34 and is received. Reference numeral 38 denotes a rolling element interposed between the inner and outer rings 33 and 34.

[0004]

In the above-mentioned conventional rolling bearing for protection, if it is removed after several touchdowns or during a periodic inspection of the molecular pump, it is replaced if it is damaged. If there is no damage, the same bearing may be used again. However, in order to remove the rolling bearing, in a device in which the bearing 32 is attached to the stator column 30, after the cover 35 is removed, the jig ( (Not shown) by pulling the tip and pulling it out in the axial direction. At the time of this pulling, indentations may be formed on the tracks of the inner and outer rings 34 and 33, which may hinder the reuse of the bearing 32.

Accordingly, an object of the present invention is to provide a protective rolling bearing for a magnetic bearing which can remove the rolling bearing without making an indent on the raceway of the bearing.

[0006]

According to a first aspect of the present invention, there is provided a magnetic bearing device in which a rotating portion is supported by a magnetic bearing in a non-contact state with respect to a fixed portion and is rotated. , The outer race or the inner race is fixed to the circumferential step of the fixed part, and the inner race or the outer race when the rotating part is stopped is a protective rolling bearing that receives the rotating part, and the outer race outer peripheral surface of the bearing or the inner race. A flange is formed on the peripheral surface so as to extend radially outward or inward, the flange is fixed to a fixed portion, and a jig engaging portion is provided at an end of the flange. Features.

According to a second aspect of the present invention, there is provided a magnetic bearing device in which a rotating portion is supported by a magnetic bearing in a non-contact state with respect to a fixed portion and is rotated. A protective rolling bearing in which an outer ring is sandwiched and fixed between attached covers and receives a rotating part by an inner ring when the rotating part stops, and a radially outer flange is formed on an outer peripheral surface of an outer ring of the bearing. A flange is sandwiched between the cover and the fixed portion, and a jig engaging portion is provided at an end of the flange.

Further, the invention according to claim 3 is characterized in that the flange is formed integrally with an L-shaped cross-section case which is fitted to the end face and the outer peripheral face of the outer race on the side of the circumferential step. I do.

Further, the invention described in claim 4 is characterized in that the flange is formed integrally with the outer peripheral surface of the outer ring.

Further, the invention according to claim 5 is characterized in that at least one surface between the L-shaped case and the fixing member is coated with a fixing lubricant.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. Note that the embodiment relates to a protective rolling bearing in a magnetic bearing device such as a turbo molecular pump, for example, and the motor mechanism, the protective rolling bearing structure in the magnetic bearing device, and the operation are the same as those in the related art. Omit the description,
The structure of the present invention will be described. In FIG. 1, an end surface 1a of an aluminum stator column 1, which is a fixed side, is formed in a substantially flat surface, and a circumferential step 2 is formed in the axial direction from this flat surface. The outer ring 4 of the rolling bearing 3 is
On one end surface 4a and the outer peripheral surface 4b. The depth of the bottom surface 2a and the length of the side surface 2b of the circumferential step portion 2 are such that the inner ring 5 projects radially from the circumferential step portion 2 when the bearing 3 is mounted, and a part of the outer ring 4 The shape is designed so as to protrude in the axial direction from the end surface 1a of the column 1. The gap between the inner peripheral surface of the inner race 5 and the rotor 6 on the rotating side is the same as in the related art.

Further, a case 7 having a substantially L-shaped cross section is fitted to one end surface 4a and the outer peripheral surface 4b of the outer race 4 on the side of the circumferential step portion 2 and the case 7 is placed in direct contact with the circumferential step portion 2. The end of the case 7 on the outer peripheral surface 4 b side of the outer ring 4 is bent radially outward to form a flange 8. The flange 8 is mounted on the end surface 1a of the stator column 1.

A cover 9 is mounted on the other end surface 4c of the outer race 4 so as to clamp the flange 8, and a screw hole 13 is formed in the end surface 1a of the stator column 1. Through holes 11 and 12 are formed in the cover 9 and the flange 8 so as to face the position, respectively.
0 is screwed into the screw hole 13 from the outer surface of the cover 9 through the through holes 11 and 12. Thereby, the bearing 3
With the flange 8 held between the cover 9 and the end face 1a of the stator column 1, the flange 8 is similarly held and fixed between the cover 9 and the stator column 1.

Further, a peripheral step 14 is formed on the end face of the flange 8 on the side of the stator column 1 so that a pull-out jig 15 for removing a bearing described later is engaged. This engagement structure is not limited to this, and any structure may be used as long as at least the jig is engaged.

The structure using the case 7 has the advantages that the flange 8 can be easily formed, the impact is absorbed at the time of touchdown, and the aluminum stator column 1 is hardly damaged. Therefore, when it is desired to reduce the number of parts, the case 7 may be omitted, and the flange 8 may be integrally formed on the outer peripheral surface 4b of the outer ring 4.

Further, at least one of the contact portion between the case 7 and the stator column 1, for example, the side surface 2b of the circumferential step portion 2 and the outer peripheral surface of the case 7 in contact therewith, is provided with a solid lubricating material such as molybdenum disulfide. The agent may be coated. This coating facilitates attachment and detachment of the flange 8 described later. The solid lubricant is applied to at least one of the flange 8 and the end surface 1a of the stator column 1 and at least one of the bottom surface 2a of the circumferential stepped portion 2 and the bottom surface of the case 7 in contact with the same. You may make it coat.

Next, the removal of the bearing will be described.
In FIG. 1, when the bearing 3 is removed, the magnetic bearing device is disassembled, and the disassembled unit in the state of the bearing 3 fixed to the stator column 1 with the cover 9 is taken out, as shown in FIG.
The cover 9 is removed by removing the screw 10 in the direction of arrow A. Thereafter, the distal end of the pull-out jig 15 is hooked on the peripheral step 14 at the end of the flange 8, pulled out along with the bearing 3 in the axial direction outward (in the directions of arrows B ₁ and B ₂ ), and the bearing 3 is removed from the stator column 1. . Accordingly, since the inner ring 5 of the bearing 3 is not directly pulled out by the jig 15 as in the related art, there is no possibility that an indentation is generated on the track of the bearing 3. Therefore, no trouble occurs when the bearing 3 is reused.

In the magnetic bearing device, as shown in FIG.
, And a protective rolling bearing 45 is provided on a circumferential step portion 42 provided on the outer periphery of the stator column 41. During touchdown, the inner peripheral surface of the cylindrical rotor 46 is provided. May be received in contact with the outer ring outer peripheral surface 45a. In such a structure, the case 47 having a substantially L-shaped cross section is attached to the inner ring inner peripheral surface 45b of the protective rolling bearing 45. It is fixed to the circumferential step 42 of the column. In this case, the flange 47a of the case 47 is formed by being bent radially inward. This case 47 is fixed to the stator column 41 using the cover 49 and the screw 50 as in the above embodiment. The case 47 has a peripheral step portion 44 for engaging a jig. In the case of such a structure, as in the previous embodiment, when removing the protective bearing, after removing the screw 50 and the cover 49, the peripheral step 4 formed on the flange 47a of the case 47 is removed.
By removing the jig by engaging it with the jig 7b, it is possible to prevent indentations from being made on the tracks of the inner and outer rings.

FIG. 4 shows a structure in which the protective bearing is removed without using a case as in the above-described embodiment. 56
Is a rotor. A bearing 55 for protection is housed in a circumferential step 52 formed in the stator housing 51.
The protection bearing 55 includes an inner ring 55a, an outer ring 55b, and a ball 55c.
Consists of A groove 69 for inserting a jig 65 for removing a bearing is formed in the cylindrical side wall 52 a of the circumferential step portion 52. The groove 69 has a substantially L-shaped cross section and extends to the bottom surface 52 b of the circumferential step 52. The jig 65 used for detachment has a pair of claws 65a, 65a, which are attached so as to be rotatable in the directions of arrows A, B about the connecting portion 65b. According to this structure, as shown in FIG. 4B, the tip of the substantially L-shaped claw 65a of the jig 65 is inserted into the groove 69 of the circumferential step 52, and the tip of the claw 65a is fitted to the outer ring 55a of the bearing. The bearing 55 can be removed from the circumferential step 52 by directly engaging the end face and pulling it up. Since the claw portion 65a lifts the outer ring 55a of the bearing in contact with the circumferential step portion 52, it is possible to prevent indentation on the track. Although not shown, also in this structure, the protective bearing 56 is fixed to the stator column by a cover and a screw. Note that FIG. 4C is the same as FIG.
Although it is a view as viewed from the direction of arrow a, the protective rolling bearing 55, the cover, and the screws are omitted for easy understanding of the structure.

[0020]

As described above, in the present invention, since the bearing is pulled out from the fixing member by the jig using the flange formed on the outer peripheral side of the bearing, no indentation is generated on the track of the bearing. Therefore, the bearing can be reused after being removed. When a coating made of a solid lubricant is interposed between the flange and the fixing member, the flange can be more easily removed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory view of removing the bearing of FIG. 1;

FIG. 3 is a sectional view of another embodiment of the present invention.

FIG. 4 is a cross-sectional view of the embodiment when no case is used.

FIG. 5 is a sectional view of a conventional protection rolling bearing.

[Explanation of symbols]

 1,41 Stator column 2,42 Peripheral step 3,45 Rolling bearing 4,45a Outer ring 5,45b Inner ring 6,46 Rotor 7,47 Case 8,47a Flange 9,49 Cover 14,47b Peripheral step 15 Pull-out jig Ingredient

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshihisa Kawakami 3-5-8 Minamisenba, Chuo-ku, Osaka-shi Koyo Seiko Co., Ltd. F-term (reference) 3J017 AA06 CA06 DA01 DB01 DB07 3J102 AA01 BA02 BA17 CA14 CA20 CA40 GA06

Claims (5)

[Claims] 1. A magnetic bearing device for rotating a rotating part by supporting a rotating part in a non-contact state with a fixed part by a magnetic bearing,
An outer ring or an inner ring is fixed to a circumferential step portion of a fixed portion, and is a protective rolling bearing for receiving a rotating portion at an inner ring or an outer ring when the rotating portion is stopped, wherein the outer ring outer peripheral surface of the bearing or the inner ring inner peripheral surface. A radially outward or inwardly extending flange is formed, the flange is fixed to a fixed portion, and a jig engaging portion is provided at an end of the flange. Rolling bearing for use in magnetic bearing devices. 2. A magnetic bearing device in which a rotating part is supported by a magnetic bearing in a non-contact state with respect to a fixed part and is rotated.
A protective rolling bearing in which an outer ring is sandwiched and fixed between a circumferential step portion of a fixed portion and a cover attached to the fixed portion, and a rotating portion is received by an inner ring when the rotating portion is stopped. 2. The method according to claim 1, wherein a radially outer flange is formed, the flange is sandwiched between the cover and the fixed portion, and a jig engaging portion is provided at an end of the flange. Rolling bearings for protection in magnetic bearing devices. 3. The magnetic bearing device according to claim 2, wherein the flange is formed integrally with an L-shaped cross-section case that is fitted to the end face of the outer ring on the side of the peripheral step and the outer peripheral surface. Rolling bearings for protection. 4. The protective rolling bearing according to claim 2, wherein the flange is formed integrally with the outer peripheral surface of the outer ring. 5. The protective rolling bearing according to claim 2, wherein a fixed lubricant is coated on at least one surface between the case having the L-shaped cross section and the fixed member.