CN113266637A

CN113266637A - Inner ring normally-separated type protective bearing

Info

Publication number: CN113266637A
Application number: CN202110485820.4A
Authority: CN
Inventors: 李子麟; 王子羲; 王玉明
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2021-08-17
Anticipated expiration: 2041-04-30
Also published as: CN113266637B

Abstract

The invention relates to the field of shooting magnetic suspension bearing systems, in particular to an inner ring normally-separated type protective bearing, which comprises a bearing inner ring, a bearing outer ring, a rolling body and a retainer, wherein the protective bearing can bear axial load and radial load simultaneously; the bearing outer ring, the rolling body and the retainer are combined into a bearing main body part and fixed on the bearing seat; the bearing inner ring can be separated from the bearing main body part and is arranged at the end part of the rotor in an interference fit mode; the protective bearing is in a static state when the magnetic suspension bearing rotor works normally, and axial and radial gaps exist between the rotor and the bearing inner ring and the bearing main body when the rotor and the bearing inner ring rotate; when the rotor and the bearing inner ring fall downwards to contact with the bearing main body, the inner track of the bearing inner ring is tightly attached to the rolling body, the rotor is fixed on the bearing, the stable bearing support is obtained, and the instability of the rotor is avoided.

Description

Inner ring normally-separated type protective bearing

Technical Field

The invention relates to the technical field of magnetic suspension bearing systems, in particular to a bearing protection device for the falling of a vertical magnetic suspension rotor.

Background

In magnetic bearing systems, a protective bearing (touchdown bearings) is one of the key components of a magnetic bearing to limit the maximum displacement of the rotor in the radial and axial directions. When the magnetic suspension bearing falls due to overload or component failure, the protective bearing can temporarily support the rotor until the rotor recovers the suspension state or safely reduces the speed, so that the damage to the main components of the magnetic suspension bearing is avoided, and the safety and the reliability of the system are ensured. However, because a certain gap exists between the rotor and the protective bearing, the rotor can generate bounce and full-circle friction within the range of the gap, and the whirling motion of the rotor can cause violent collision and friction to the inner ring of the bearing. Particularly, for a vertical magnetic suspension rotor, gravity constraint is not generated in the radial direction, the bearing inner ring can continuously bear contact force which is 3-10 times of the self weight of the rotor due to the whirling action of the rotor, the bearing is easily damaged, the generated friction force and friction torque can possibly cause rapid temperature rise of a protection bearing, and the service life of the protection bearing is shortened. At present, the reliability of the protective bearing becomes one of the bottlenecks of the industrialized application of the magnetic suspension bearing.

Aiming at the vertical magnetic suspension bearing, on the premise of not additionally increasing system spare and accessory parts, a protective bearing structure is redesigned, so that the protective bearing is distinguished from the traditional working mode, the gap of the protective bearing is eliminated when the rotor falls, the rotor is stably supported, and the reliability of the protective bearing is improved.

Disclosure of Invention

In order to overcome the problem of insufficient reliability in the prior art, the invention provides the inner ring normally-separated type protection bearing, which avoids the contact force of rotor whirling response and collision caused by the clearance between the inner ring of the protection bearing and a rotor, and effectively improves the durability of the protection bearing.

The technical scheme adopted by the invention for solving the technical problems is as follows: an inner ring normally-separated type protection bearing comprises a bearing outer ring, a rolling body, a retainer and a bearing inner ring;

the protective bearing needs to be capable of bearing axial load and radial load at the same time, mainly axial load, and the sizes and technical requirements of the outer ring and the rolling body of the bearing are the same as those of the angular contact ball bearing with the same specification;

the protective bearing outer ring, the rolling body and the retainer are combined into a bearing main body part and fixed on the bearing seat; the bearing inner ring can be separated from the bearing main body part and is arranged at the end part of the rotor in an interference fit mode;

the protection bearing is in a static state under the normal work of a magnetic suspension bearing rotor, and axial and radial gaps exist between the rotor and a bearing inner ring and a bearing main body when the rotor and the bearing inner ring rotate; when the rotor is in a destabilization event, the rotor and the bearing inner ring fall downwards to contact with the bearing main body, the inner track of the bearing inner ring is tightly attached to the rolling body, the rotor is fixed on the bearing to obtain stable bearing support, and the centrifugal force of the rotor is effectively reduced.

According to another embodiment of the present invention, further comprising: the protective bearing retainer has a limiting effect on the rolling element, has the capacity of fixing the rolling element under the vertical installation condition, and ensures that the rolling element does not fall off from the bearing main body part when no inner ring is limited.

According to another embodiment of the present invention, further comprising: the inner raceway surface of the bearing inner ring is in smooth transition, has no limiting effect on the rolling body, and has no damping during axial separation.

According to another embodiment of the present invention, further comprising: the rotor, the bearing inner ring and the bearing main body are coaxially arranged, and the bearing inner ring is uniformly contacted with each rolling body and stably supported when the rotor and the bearing inner ring fall.

According to another embodiment of the present invention, further comprising: the protective bearing only works when the magnetic suspension bearing fails and the rotor falls, is in a static state under normal work, and does not need a lubricating medium to supplement the protective bearing.

The invention has the advantages that the invention can simultaneously provide radial and axial protection for the rotor after the magnetic suspension bearing system fails, and can simultaneously reduce the radial contact force and the friction force caused by the whirling of the rotor; in addition, when the magnetic suspension bearing suspends again, the gap between the bearing inner ring and the paired shaft sleeve can be recovered in time, so that the bearing is protected from interfering the normal operation of the magnetic suspension bearing; the reliability and the safety of the vertical type protective bearing are improved, and the detection and maintenance cost of the protective bearing is reduced.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic view of an overall structure of an inner ring normally-separated protective bearing according to the present invention;

FIG. 2 is a schematic view of the inner race structure of the protective bearing of FIG. 1;

FIG. 3 is a schematic three-dimensional structure of the retainer of FIG. 1;

in the figure, 1, a rotor, 2, a bearing inner ring, 3, a retainer, 4, a rolling body, 5 and a bearing outer ring.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

An inner ring normally-separated type protection bearing according to an embodiment of the present invention will be described with reference to fig. 1, 2 and 3.

As shown in fig. 1, the inner ring normally-separated protective bearing according to the embodiment of the present invention includes a rotor 1, a bearing inner ring 2, a cage 3, rolling elements 4, and a bearing outer ring 5.

Specifically, the bearing inner ring 2 is mounted on the rotor 1 by interference fit, the cage 3, the rolling bodies 4 and the bearing outer ring 5 are separately assembled into a bearing body, the cage 3 and the bearing outer ring 5 are coaxially arranged, and the rolling bodies 4 are mounted on the cage 3 and spaced apart from each other.

After the protective bearing body is installed and vertically placed, the retainer 3 should play a limiting role for the rolling elements 4, the rolling elements should roll only in the holes of the retainer 3 along the track of the bearing outer ring 5, and the rolling elements should not fall off from the retainer under slight vibration or impact.

For this reason, as shown in fig. 3, the holes of the cage 3 are not parallel to the horizontal plane, but have an angle of 5 to 15 ° to ensure that the rolling elements 4 do not fall off under easy installation conditions.

Generally, the outer bearing ring 5 is fixed to the machine frame by means of interference fit, and the inner bearing ring 2 is fixed relative to the rotor 1, both moving synchronously.

The working principle of the invention is as follows: under the normal operation working condition, the bearing inner ring 2 is not contacted with the protective bearing main body, especially the rolling body 4, the bearing inner ring 2 rotates at high speed along with the rotor 1, and the retainer 3 and the rolling body 4 are kept in a static state. When the magnetic bearing fails, the rotor 1 falls downwards due to the action of gravity, the bearing inner ring 2 and the rolling body 4 are in collision contact, the rotor 1 stably falls on the protective bearing after bouncing for several times due to the existence of speed difference, the bearing inner ring 2 and the protective bearing main body are combined into a group of complete angular contact ball bearings, and the rotor is stably supported without vortex motion and collision. The revolution speed of the retainer 3 and the rolling bodies 4 is equal to half of the rotation speed of the bearing inner ring 2 and the rotor 1. The embodiment can effectively eliminate the whirling of the rotor, reduce the collision force between the protective bearing and the rotor, play a role in protecting the system and prolong the service life of the protective bearing.

According to one embodiment of the invention, the inner raceway surface of the bearing inner ring 2 is in smooth transition in the axial separation direction, has no limiting effect on the rolling elements, and has no damping during axial separation.

According to one embodiment of the invention, the protective bearing works only when the magnetic suspension bearing fails and the rotor falls, and is used as a bearing which does not work for a long time and is not supplemented by a lubricating medium, so that the design of the system is simplified, and the pollution of the rotor is avoided.

In the description herein, references to the description of "one embodiment," "an example," or "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A protective bearing with an inner ring normally separated comprises a bearing inner ring, a bearing outer ring, a rolling body and a retainer; the method is characterized in that:

the protection bearing needs to be capable of bearing axial load and radial load at the same time, mainly axial load, and the sizes and technical requirements of the bearing outer ring and the rolling body are the same as those of the angular contact ball bearing with the same specification;

the protective bearing is in a static state when the magnetic suspension bearing rotor works normally, and axial and radial gaps exist between the rotor and the bearing inner ring and the bearing main body when the rotor and the bearing inner ring rotate; when the rotor is in a destabilization event, the rotor and the bearing inner ring fall downwards to contact with the bearing main body, the inner track of the bearing inner ring is tightly attached to the rolling body, the rotor is fixed on the bearing to obtain stable bearing support, and the centrifugal force of the rotor is effectively reduced.

2. The inner ring normally separated type protective bearing according to claim 1, wherein the protective bearing retainer has a limiting effect on the rolling elements, and has a capability of fixing the rolling elements in a vertical installation condition, so that the rolling elements are prevented from falling off from the bearing main body part without inner ring limiting.

3. The inner race normally-separated protective bearing of claim 1, wherein the inner race surface of the bearing inner race is in smooth transition, has no limiting effect on the rolling elements, and has no damping during axial separation.

4. The inner ring normally separated type protective bearing according to claim 1, wherein the rotor, the bearing inner ring and the bearing main body part are coaxially arranged, and the bearing inner ring is uniformly contacted with each rolling body and stably supported when the rotor and the bearing inner ring fall.

5. The self-centering protective bearing assembly for a vertical magnetic bearing gantry of claim 1, wherein the protective bearing is operated only when the magnetic bearing fails and the rotor falls, and is in a stationary state under normal operation without the need of a lubricating medium to supplement the magnetic bearing.