JPH02280646A - Magnetic bearing type electric rotary machine - Google Patents

Abstract

PURPOSE:To prevent damage due to abnormal collision of rotary shaft and protective bearing by arranging an elastic shock absorbing body at the contacting section between them. CONSTITUTION:A magnetic bearing 16 bears a rotary shaft 15 and a rotor 14, in contactless, at the opposite sides thereof. A protective bearing 20 contacts with the opposite end sections of the rotary shaft 15, when the magnetic bearing 16 is not operating, and supports the rotary shaft 15. An elastic shock absorbing body 24 is fitted in a groove section 32a made at the inner circumferential side of a ring 23 to be fitted to the inner ring 21b of a ball bearing 21 in the protective bearing 20. In the operation, when the magnetic bearing 16 is disabled due to power interruption and the rotary shaft 15 moves in the circumferential direction, the rotary shaft drops onto the protective bearing 20 and contacts with the shock absorbing body arranged in the protective bearing. Since collision impact of the rotary shaft and the protective bearing is absorbed by the shock absorbing body, the rotary shaft and the protective bearing are held by the protective bearing with no damage.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention provides a magnetic bearing that holds a rotating shaft in a non-contact state, and a magnetic bearing that holds the rotating shaft in a contact state when the magnetic bearing is not in operation. The present invention relates to a magnetic bearing type rotating electric machine equipped with a protective bearing.

(Prior Art) A conventional example of this type of rotating electrical machine is shown in FIG. 4, and its configuration will be briefly described. Reference numeral 1 denotes a frame, a stator 2 is disposed at the center of the frame, and bearing brackets 3 are fixed to both ends. 4 is a rotor corresponding to the stator 2, and a rotating shaft 5 is fixed to the center of the rotor. 6 is (j rotation axis 5
A pair of radial magnetic bearings are used to support the rotor 4 on both sides of the rotor 4 in a non-contact manner, and consist of a magnetic body 7 fixed to the rotating shaft 5 and a stator 8 surrounding it and fixed to the frame 1. Reference numeral 9 denotes a pair of protective bearings, each of which is constituted by a ball bearing provided on a bearing bracket 3, and the rotary shaft 5 is prevented from coming into contact with these while the magnetic bearing 6 is in operation.

Thus, during operation of the rotating electrical machine, the magnetic bearing 6 operates, and the rotating shaft 5 is held in a non-contact state, that is, in a state in which it does not contact the protective bearing 9. On the other hand, when the rotating electric machine is stopped or the power to the magnetic bearing is cut off, the magnetic bearing 6
The holding force in the non-contact state is lost, and the rotating shaft 5 falls into the retainer bearing 9, and is held in the contact state by the retainer bearing 9. Therefore, rr! ! Even when the power to the magnetic bearing 6 is cut off, it is possible to prevent damage caused by the rotation r4 coming into contact with the stator 2 or the magnetic body 7 of the magnetic bearing 6 coming into contact with the stator 8.

(Problem to be Solved by the Invention) However, with the above configuration, when the rotating electric machine is operating at high speed, abnormalities such as the 7i source of the magnetic bearing 6 being cut off and the magnetic bearing 6 not functioning may occur. When it occurs,
Depending on the load condition, the rotating shaft 5 may suddenly move in the radial direction, and as a result, the rotating shaft 5 and the protective bearing 9
There was a problem in that there was a risk of damage due to collision.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic bearing type rotating electric machine that can prevent damage caused by collision between a rotating shaft and a protective bearing even when the magnetic bearing is abnormal.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a magnetic bearing that holds a rotating shaft on both sides of a rotor in a non-contact state, and a magnetic bearing that holds the rotating shaft on both sides of a rotor in a non-contact state, and when the magnetic bearing is not in operation, the rotating shaft is held on both sides of the rotor. The present invention is directed to a magnetic shaft-dominant rotating electrical machine equipped with a protective bearing held in contact on both sides of the rotating shaft, and is characterized in that a buffer made of an elastic material is provided at a portion of the protective bearing that contacts the rotating shaft. .

(Operation) Suppose that while a rotating electric machine is operating at high speed, the magnetic bearing stops functioning due to power cut-off or the like, and the rotating shaft suddenly moves in the radial direction. Then, the rotating shaft falls onto the protective bearing and comes into contact with a shock absorber made of an elastic material provided on the protective bearing. As a result, the shock caused by the collision between the rotating shaft and the protective bearing is absorbed by the buffer, and the rotating shaft and the protective bearing are held by the protective bearing without being damaged.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIGS. 1 and 2.

First, in FIG. 1 showing the overall structure, 11 is a frame, a stator 12 is disposed at the center of the frame, and bearing brackets 13 are fixed to both ends. 14 is a rotor corresponding to the stator 12, and a rotating shaft 15 is located at the center of this rotor.
is fixed. Reference numeral 16 denotes a pair of radial magnetic bearings for supporting the rotating shaft 15 on both sides of the rotor 14 in a non-contact manner. and a stator 18.

19 is a rotating shaft position detector located near each magnetic bearing 16 and provided on the frame 11, which detects the position of the rotating shaft 15 and detects the position of the rotating shaft 15 so that it is located at the center of the stator 18. This is for controlling the excitation of the 16 stators 18.

Reference numeral 20 denotes protective bearings, each of which is fixed in a storage section 13a provided by opening the center of the bearing bracket 13, and is rotatable. Both ends of the magnetic bearing 115 are in contact with and supported when the magnetic bearing [6] is not in operation. In detail, it is configured as shown in FIG. That is, in FIG. 2, which shows an enlarged view of the protective bearing 20, 21 is a ball bearing, the outer ring 21a of which is fitted into the housing part 13a of the bearing bracket 13, and the bearing bracket 13 and the bearing retainer 2.
2 and are fixed in a sandwiched manner. Reference numeral 23 denotes a ring attached to the inner ring 21b of the ball bearing 21, and a buffer body 24 made of an elastic material, for example, hard rubber, is fitted and fixed in a groove 32a provided on the inner circumferential side of the ring. The shock absorber 24 is brought into contact with the shock absorber 24 of the Both end portions of the rotating shaft 15 corresponding to the protective bearings 20 have a stepped shape with a smaller diameter.

Now, in the above configuration, during operation, the rotating shaft 15 is supported without contact by the magnetic bearing 16, and stable high-speed rotation is performed. During such rotation, if an accident such as power interruption of the magnetic bearing 1b occurs, the rotating shaft 15 may suddenly move toward the radial knob depending on the load condition. Then, the rotating shaft ] 5 collides with the buffer body 24 of the protective bearing 20 . However, since the impact at this time is absorbed by the elastic deformation of the buffer, the rotating shaft 15 and the ball bearing 21 of the protective bearing 20 are not damaged by the impact, and the rotating shaft 15 is held by the protective bearing 2o. .

According to this embodiment, even if the rotating shaft 15 moves in the radial direction and collides with the inner ring 21b of the ball bearing 21 during an abnormality such as power cut off of the magnetic bearing 16, the impact is absorbed by the shock absorber 2.
4 can be absorbed. This allows rotation axis]
5 and ball bearing 21 can be prevented from occurring.

FIG. 3 shows a second embodiment of the present invention.
Only the parts that are different from the embodiment will be explained.

That is, 25 is a protective bearing provided in place of the protective bearing 2U in the first embodiment, and the inner ring 26b of the ball bearing 26 is provided with two grooves 26c, 26c.
With the buffer body 27.27 inserted directly into 26c and fixed, fX? has been completed.

Therefore, the second embodiment can also provide the same effects as the first embodiment.

Note that the present invention is not limited to the above embodiments,
Each protective bearing may be constructed with a ball bearing of 2 pI or more, and various modifications can be made without departing from the scope of the invention.

[Effects of the Invention] As described above, in the present invention, since a shock absorber made of an elastic material is provided on the frame side at the portion of the protective bearing that comes into contact with the rotating shaft, rotation can be prevented even when an abnormality occurs in the magnetic bearing. This has the excellent effect of preventing damage to the rotating shaft and the protective bearing due to shaft collision.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, in which FIG. 1 is an overall sectional view, FIG. 2 is an enlarged sectional view of main parts, and FIG.
The figure is a view corresponding to FIG. 2 showing a second embodiment of the present invention, and FIG. 4 is a view equivalent to FIG. 1 showing a conventional example. In the drawing, 11 is a frame, ] 3 is a bearing bracket, 14
is a rotor, 15 is a rotating shaft, 16 is a magnetic bearing, 20.25
is a protective bearing, 21.26 is a ball bearing, 23 is a ring, 24
．． 27 is a buffer body. Agent Patent Attorney Norihiro Chika Kendai No. 1 Figure Tori Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] 1. A magnetic bearing that holds the rotating shaft on both sides of the rotor in a non-contact state, and a protective bearing that holds the rotating shaft on both sides of the rotor in a contact state when the magnetic bearing is not in operation. . A magnetic bearing type rotating electrical machine, characterized in that a buffer made of an elastic material is provided at a portion of the protective bearing that comes into contact with the rotating shaft.