JPH08285565A - Bearing monitor - Google Patents

Abstract

PURPOSE: To enable quantitative evaluation by arranging a rotary member facing a bearing within a support member fixing the bearing so as to be allowed to contact one end thereof and providing a plurality of notches at opposed parts to detect wearing of the bearing easily without using a vibration meter. CONSTITUTION: Thrust washers 42 and 44 pivoted on a rotor shaft 24 are arranged in bearing housings 38 and 40 so as to be allowed to contact one end part of bearings 34 and 36. A clearance between the washers 42 and 44 and the housings 38 and 40 are set smaller than a clearance β between a rotor can 32 and a stator can 30. It is also so arranged to keep both the parts from contacting each other in the normal state. A plurality of tooth-shaped notches are arranged at one end of the housing 38 being separated in the circumferential direction at a specified interval. Thus, during the eccentric rotation of the rotor shaft 24 associated with wearing of the bearings 34 and 36, a peak with a larger vibration level is generated in the frequency characteristic thereof near a value as obtained by multiplying the frequency of a power source by the number of the notches. The monitor thus obtained is hardly affected by the effect of disturbances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing monitor for detecting a worn state of a bearing that supports a rotor shaft in a rotary electric machine such as a canned motor.

[0002]

2. Description of the Related Art Generally, a slide bearing is used as a bearing of a rotor shaft of a canned motor portion in a canned motor pump. However, depending on the material of the slide bearing, it will be worn out for a long period of time. Therefore, such wear of the bearing causes contact between the impeller and the casing in the pump section or contact between the rotor and the stator in the canned motor section, which may prevent normal pump performance from being exerted and also cause pump operation. There is a drawback that will stop.

For this reason, in this type of bearing, a bearing monitor is required to detect the wear when the amount of wear exceeds a certain level.

From such a point of view, conventionally, for example, at the end of the rotor of a canned motor, detectors in which air or an inert gas is sealed at a predetermined pressure are arranged so as to face each other, and the bearing is in the thrust direction or radial direction. Eccentric rotation of the rotor shaft due to eccentric rotation when worn in a single direction or in a combined direction of both, causing a part of the rotor shaft to come into contact with the detector, causing the detector to rupture. A bearing monitor configured to detect this state is known.

However, the bearing monitor having such a mechanical structure has a problem in that high precision is required in manufacture when it is installed in the canned motor, and it is a consumable item, which requires troublesome maintenance.

On the other hand, as a bearing monitor in an AC rotating electric machine, a plurality of detection coils are incorporated in a stator assembly with a specific space angle, and these detection coils are connected in series to detect a combined induced voltage. Accordingly, there has been proposed a device having a configuration for detecting an eccentric state of the rotor due to bearing wear or the like.

However, such an electrically operated bearing monitor has advantages that it is easy to manufacture because it is incorporated as a component of a canned motor and maintenance is simple, but this type of bearing monitor is Due to the directivity of the detection sensitivity due to the structure of the detection coil, it is not possible to achieve proper detection for a specific bearing wear direction, and it is also impossible to achieve proper detection due to an external inductive obstacle. There is a drawback.

Therefore, in order to further overcome the above-mentioned problems of the conventional bearing monitor, the applicant of the present invention has made a detection made of an abradable metal so as to surround the rotor shaft coaxially with the radial bearing that supports the rotor shaft. A ring is arranged, and the outer diameter of the detection ring is set larger than the inner diameter of the radial bearing with respect to the outer diameter of the rotor shaft.
The deviation β of the inner diameter is set to be slightly smaller than the separation distance α between the rotor can and the stator can (β <α), the radial bearing and the detection ring are integrally provided in the bearing housing, and the vibration is generated with respect to the bearing housing. By developing a bearing monitor configured to detect mechanical vibration caused by contact of the rotor shaft that eccentrically rotates due to wear of the radial bearing with the inner diameter of the detection ring, A new model registration was obtained (Jpn.

The bearing monitor thus constructed is
It has a simple structure, can be manufactured at low cost, and has good workability when replacing the radial bearing.
There is no deterioration of the canned motor itself in relation to the bearing monitor, and it is possible to obtain a bearing monitor with excellent detection accuracy even under a light load.

[0010]

However, in the above-mentioned conventional bearing monitor, when the bearing is worn beyond the allowable limit, the machine caused by the eccentric rotation of the rotor shaft and contact with the detection ring. Dynamic vibration has the advantage that the wear state of the bearing can be easily detected with a simple configuration using a single vibrometer, but when using multiple bearings, which bearing is acceptable It is difficult to determine whether the wear state exceeds the limit. Further, the vibrometer merely senses the vibration state, and it has been impossible to quantitatively evaluate the wear state of each bearing based on the vibration output characteristics obtained by the vibrometer, for example.

Therefore, an object of the present invention is to fix a bearing to a support member (bearing housing) and to a rotor shaft supported by the bearing so that the support member can come into contact with one end of the bearing. With a rotating member (thrust washer) arranged to face each other, a notch is provided in the circumferential direction with respect to the supporting member or the rotating member, and when the bearing wears, the respective members come into contact with each other, resulting in large vibration. (EN) A bearing monitor capable of generating a sound, discriminating a bearing in a worn state by measuring a vibration characteristic by a vibrometer and quantitatively evaluating the worn state.

[0012]

To achieve the above object, in a bearing monitor according to the present invention, a rotor and a stator are hermetically sealed by a rotor can and a stator can, respectively, and a rotor shaft is surrounded and supported by a bearing and a bearing is provided in a rotor chamber. In a canned motor configured to circulate the lubricating liquid, the bearing member is fixed to the support member and the rotor shaft, and is arranged in the support member so as to be capable of contacting one end of the bearing. A rotating member is provided, and a required number of notches are provided in portions of the supporting member or the rotating member that face each other in the circumferential direction, and when the bearing is worn, the members come into contact with each other to generate a vibration sound. It is characterized by doing.

The bearings are arranged so as to respectively support both ends of a rotor shaft extending in the front and rear of the motor rotor, and the number of notches in the supporting member or the rotating member provided for these bearings is set to be different. be able to.

Further, the support member and the rotary member disposed in the support member so as to face the one end of the bearing so as to be able to come into contact therewith can be provided with a step portion which can come into contact with each other in the axial direction.

In this case, the notches provided in the support member or the rotating member may be tooth-shaped notches provided at predetermined intervals in portions facing each other in the circumferential direction.

Further, the supporting member for fixing the bearing may be a bearing housing, and the rotating member arranged so as to be in contact with one end of the bearing may be a thrust washer.

Further, a vibrometer may be provided in a part of the bearing housing to discriminate a bearing in a worn state and to quantitatively evaluate a worn state of the bearing by measuring a vibration characteristic.

[0018]

According to the bearing monitor of the present invention, a supporting member such as a bearing housing for fixing the bearing is fixed to the rotor shaft, and is disposed in the supporting member so as to be capable of contacting one end of the bearing. A rotary member such as a thrust washer is provided, and a required number of cutouts are provided in portions of the support member or the rotary member that face each other in the circumferential direction. By generating the above, it is possible to obtain a sudden increase in the vibration level when the respective members come into contact with each other, thereby obtaining a large vibration sound, and easily detecting the wear state of the bearing without using a vibrometer. You can

[0019]

Embodiments of the bearing monitor according to the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing the structure of a canned motor pump to which the bearing monitor according to the present invention is applied. In FIG. 1, reference numeral 10 is a pump portion, 12
Indicates a canned motor unit.

The pump section 10 is provided with a pump chamber 18 having an impeller 16 in a pump casing 14, and has a suction pipe section 20 and a discharge pipe section 22 which are in communication with each other in the pump chamber 18, respectively. Is the canned motor unit 1
It is attached to the extended end of the two rotor shafts 24.

On the other hand, the canned motor portion 12 comprises a stator assembly 26 and a rotor assembly 28.
The inner peripheral portion of 6 is surrounded by a stator can 30, and the outer peripheral portion of the rotor assembly 28 is sealed by a rotor can 32.
The rotor shaft 24 is supported by a front bearing 34 and a rear bearing 36, respectively, and the front bearing 34 and the rear bearing 36 are fixedly supported by bearing housings 38 and 40, respectively. The rotor shaft 24 has the bearings 34 and 36 in the bearing housings 38 and 40.
Thrust washers 42 and 44 are arranged so as to be able to contact one end of the. A front rotor chamber 46 and a rear rotor chamber 48 are provided at both ends of the rotor assembly 28, respectively.
And are formed.

In the thus constructed canned motor pump of this embodiment, a part of the pump handling liquid sucked into the pump chamber 18 of the pump portion 10 is provided in the bearing housing 38 from the rear surface of the outer peripheral portion of the impeller 16. Through hole 50
Then, the liquid is introduced into the front rotor chamber 46 via the liquid passage 52. A part of the handling liquid introduced into the front rotor chamber 46 partially lubricates the front bearing 34 while the rotor shaft penetrating gap of the bearing housing 38 and the impeller 16 are provided.
Through the balance hole 54 of 1. to the low pressure side of the pump portion 10. In addition, most of the handled liquid introduced into the front rotor chamber 46 passes through between the rotor and the stator and then flows into the rear rotor chamber 48.
And the canned motor unit 12 is cooled. Further, a part of the handled liquid guided to the rear rotor chamber 48 flows into the rear liquid chamber 56 surrounded by the bearing housing 40 while lubricating the rear bearing 36. Also,
Most of the handled liquid guided to the rear rotor chamber 48 flows into the rear liquid chamber 56 through a through hole 58 provided in the bearing housing 40. In this way, the handled liquid that has flowed into the rear liquid chamber 56 appropriately flows back to the low pressure side of the pump unit 10 through the liquid passage holes (not shown) formed in the rotor shaft 24.

However, according to the present invention, the bearings 34 and 36 are positioned so as to be in contact with one ends of the bearings 34 and 36,
Thrust washer 4 mounted on each rotor shaft 24
2, 44 are arranged in each bearing housing 38, 40. And in this case, the thrust washer 4
Gap between 2,44 and bearing housing 38,40 α
(See FIG. 3), the rotor can 32 and the stator can 3
The value is set to be smaller than the gap β (see FIG. 1) with 0, and when the bearings 34 and 36 are normal, the thrust washers 42 and 44 and the bearing housing 3
8 and 40 are configured so as not to contact with each other.

FIG. 2 shows the thrust washer 42 (4
4) shows an embodiment relating to a specific combination configuration of the bearing housing 38 (40) and 4). That is, the embodiment shown in FIG. 2 has a configuration in which one end portion of the bearing housing 38 is provided with tooth-shaped notches 60 (three in the illustrated example) at predetermined intervals in the circumferential direction.

According to the combination of the thrust washer 42 and the bearing housing 38 of the present embodiment thus constructed, as shown in FIG. 3, the bearings (34, 36) are provided.
In a normal state, the thrust washer 42 and the bearing housing 38 do not come into contact with each other (see FIG. 3A), and when the wear amount of the bearings (34, 36) exceeds the gap α, the rotor shaft 24 is The thrust washer 42 comes into contact with the bearing housing 38 by eccentric rotation [Fig.
(B)].

In the eccentric rotation of the rotor shaft 24 that occurs in this case, the center of rotation of the rotor shaft 24 deviates from the center of gravity of the rotor and the center of rotation of the rotor shaft, and It appears as a cam motion state that describes a cam-like eccentric motion, and a combined state of these whirling and cam motion states.

However, the frequency characteristics associated with the eccentric rotation of the rotor shaft 24 when the notch 60 is not provided are as shown in FIG. That is, (a) of FIG.
Shows the case of the whirling state, and FIG.
Shows the case of the cam motion state, and FIG.
Shows respective cases of the above-mentioned combined state.

On the other hand, in the case of this embodiment,
As shown in FIG. 5, when the number of notches 60 is 3, when the eccentric rotation of the rotor shaft 24 is in the combined state,
The frequency characteristic as shown in FIG. 5A is obtained. Similarly, when the number of notches 60 is 4, (b) in FIG.
The frequency characteristics shown in are obtained.

As described above, according to the present embodiment, in the eccentric rotation of the rotor shaft 24 due to the wear of the bearings 34 and 36, the frequency characteristics thereof are as shown in FIGS. A large peak value occurs when the power supply frequency f is n times the number of the notches 60, that is, near (f × n) [Hz]. Therefore, as compared with the configuration of the conventional bearing monitor, there is an advantage that it is less susceptible to the influence of disturbance.

Therefore, in the present embodiment, the front and rear bearing housings 38,
The number of notches 60 is set differently for 40.
Thereby, as shown in (a) and (b) of FIG.
Large peak values occur at different frequencies, so
By detecting these frequencies, it is possible to easily determine which bearing is worn.

FIG. 6 shows another embodiment relating to the specific combination of the thrust washer 42 (44) and the bearing housing 38 (40). That is, in the embodiment shown in FIG. 6, the thrust washer 4
The outer peripheral portion of 2 has a configuration in which tooth-shaped notches 62 (three in the illustrated example) are provided at predetermined intervals in the circumferential direction.

According to the combination of the thrust washer 42 and the bearing housing 38 of the present embodiment thus constructed, as shown in FIG. 7, the bearings (34, 36) are provided.
Is normal, the thrust washer 42 and the bearing housing 38 are not in contact with each other (see FIG. 7A), and when the wear amount of the bearings (34, 36) exceeds the gap α, the rotor shaft 24 is The thrust washer 42 comes into contact with the bearing housing 38 by eccentric rotation [Fig.
(B)].

Therefore, also in this embodiment, it is possible to obtain the same operation and effect as in the above embodiment.

8 and 9 show the thrust washer 42.
It shows yet another embodiment relating to a specific combination configuration of (44) and the bearing housing 38 (40). That is, in the embodiment shown in FIGS. 8 and 9, similarly to the embodiment shown in FIG. 2, one end portion of the bearing housing 38 is provided with a tooth-shaped notch 64 (in the illustrated example, a tooth-shaped cutout 64 spaced apart at a predetermined interval in the circumferential direction). 4) are provided, and step portions 66 are formed on the inner peripheral surface of the end portion of the bearing housing 40 which extends by the notches 64. On the other hand, the thrust washer 44 having the step portion 68 is formed so as to correspond to the inner peripheral surface of the end portion of the bearing housing 38 where the step portion 66 is formed.

According to the combination of the thrust washer 42 and the bearing housing 40 of the present embodiment thus constructed, the thrust washer 44 and the bearing housing 40 are brought into contact with each other in the radial direction, whereby the bearing (36)
The wear state in the radial direction of can be detected. Further, the axial contact between the thrust washer 44 and the bearing housing 38 (contact between the step portion 66 and the step portion 68) makes it possible to detect the axial wear state of the bearing (36).

However, when the bearing monitor of this embodiment is applied to the canned motor pump, the configuration shown in FIG.
Bearings 34, 36 and bearing housings 38, 40 and thrust washers 42, 4 as shown in FIG.
4 is arranged and arranged. In this case, the radial clearance α between the thrust washers 42, 44 and the bearing housings 38, 40 with respect to the front and rear bearings 34, 36.
Is the gap β between the rotor can 32 and the stator can 30.
By setting the value to be smaller, it is possible to properly detect the wear state of the bearings 34 and 36 in the radial direction, as in the above-described embodiment. Also, the axial gaps γ and δ between the thrust washers 42 and 44 and the bearing housings 38 and 40, and the impeller 16
Between the front end of the impeller 16 and the inner wall surface of the pump casing 14, and the rear end of the impeller 16 and the bearing housing 38.
By setting the relationship between the side surface of the bearing and the clearance ζ such that γ <ε and δ <ζ, the wear state of the bearings 34 and 36 in the axial direction can be properly detected.

According to the bearing monitor of this embodiment, the contact area of the step portion 68 of the thrust washers 42, 44 with respect to the step portion 66 provided in the bearing housings 38, 40 (hatched by hatching) is caused by the radial whirling of the rotor shaft. (Shown) is as shown in FIG. in this way,
Since the contact areas of the thrust washers 42, 44 with respect to the stepped portions 66 of the bearing housings 38, 40 are different, the protruding portions partitioned by the notches 64 of the bearing housings 38, 40 corresponding to the respective stepped portions 66 are vibrated. It causes an imbalance in trying force. Therefore, from the imbalance generated in this way, the frequency having a peak value of (f × n) [Hz], which is n times the number of the notches 60, with respect to the power supply frequency f as shown in FIGS. 5A and 5B. The characteristics are obtained. In this way, similar to the wear state of the radial bearing described above,
The wear state of the bearing in the axial direction can also be properly detected.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit of the present invention. For example, by providing a vibrometer on a part of the motor casing such as the bearing housing, it is possible to accurately determine the worn bearing, and
By measuring the vibration characteristics, it is possible to quantitatively evaluate the wear state of the bearing.

[0040]

As is apparent from the above-described embodiments, according to the bearing monitor of the present invention, the rotor and the stator are hermetically sealed by the rotor can and the stator can, respectively, and the rotor shaft is supported by the bearing and is surrounded by the rotor chamber. In a canned motor configured to circulate a liquid for lubricating a bearing, the bearing member is fixed to the bearing housing and the like, and is fixed to the rotor shaft, and one end of the bearing can be abutted in the support member. And a rotating member such as a thrust washer disposed opposite to each other, and a required number of notches are provided in portions of the supporting member or the rotating member that face each other in the circumferential direction. By virtue of the configuration that generates vibration sound by Can be obtained a rise in the Do vibration level (see FIG. 12), therefore for a large vibration sound can be obtained, it can be easily detected state of wear of the bearing without the use of vibrometer.

Further, in the bearing monitor of the present invention, it is possible to easily determine which bearing is worn by setting the number of notches different for each of the plurality of bearings.

Further, in the bearing monitor of the present invention, the support member and the rotary member arranged in the support member so as to face the one end of the bearing so as to be able to come into contact with the support member are axially contactable with each other. By providing the portion, it is possible to properly detect the wear state of the bearing in the axial direction by mutual contact of these step portions. Therefore, according to the bearing monitor of the present invention, it is possible to simultaneously detect the wear states of the bearing in the radial direction and in the axial direction, respectively.

Furthermore, in the bearing monitor of the present invention, a vibrometer is provided in a part of the motor casing to quantitatively evaluate the wear state of the bearing from the frequency characteristic obtained by the eccentric rotation of the rotor shaft. There are advantages that can be taken.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view of essential parts of a canned motor pump showing an embodiment in which a bearing monitor according to the present invention is applied to a canned motor pump.

FIG. 2 is a perspective view showing an embodiment of a main part configuration of a bearing monitor according to the present invention.

3A and 3B show an operating state of the bearing monitor of the embodiment shown in FIG. 2, where FIG. 3A is an operation explanatory diagram of a normal state of the bearing, and FIG. 3B is an operational explanatory diagram of a worn state of the bearing.

4A and 4B show frequency characteristics of a rotor shaft in a basic configuration of a bearing monitor according to the present invention, where FIG. 4A is a characteristic diagram in a whirling state, FIG. 4B is a characteristic diagram in a cam motion state, and FIG. ) Is a characteristic diagram in a combined state.

5A and 5B show frequency characteristics of a rotor shaft in the bearing monitor of the embodiment shown in FIG. 2, where FIG. 5A is a characteristic diagram when the number of notches is 3 and FIG. 5B is when the number of notches is 4. It is a characteristic diagram in a case.

FIG. 6 is a perspective view showing another embodiment of the main configuration of the bearing monitor according to the present invention.

7A and 7B show an operating state of the bearing monitor of the embodiment shown in FIG. 6, where FIG. 7A is an operational explanatory diagram of a normal state of the bearing, and FIG. 7B is an operational explanatory diagram of a worn state of the bearing.

FIG. 8 is an exploded perspective view showing still another embodiment of the main configuration of the bearing monitor according to the present invention.

9 is a cross-sectional view of the main part configuration of the bearing monitor of the embodiment shown in FIG.

10 is a cross-sectional side view of essential parts of a canned motor pump showing an embodiment in which the bearing monitor of the embodiment shown in FIG. 8 is applied to a canned motor pump.

FIG. 11 is an explanatory diagram showing a relationship of contact areas of members that come into contact with the respective step portions due to whirling of the rotor shaft in the bearing monitor according to the present invention.

FIG. 12 is a characteristic diagram showing changes over time in the vibration level of the peak value in the frequency characteristic of the rotor shaft in the bearing monitor according to the present invention.

[Explanation of symbols]

 10 pump part 12 canned motor part 14 pump casing 16 impeller 18 pump chamber 20 suction pipe part 22 discharge pipe part 24 rotor shaft 26 stator assembly 28 rotor assembly 30 stator can 32 rotor can 34 front bearing 36 rear bearing 38 bearing housing 40 bearing housing 42 Thrust washer 44 Thrust washer 46 Front rotor chamber 48 Rear rotor chamber 50 Through hole 52 Liquid passage 54 Balance hole 56 Rear liquid chamber 58 Through hole 60 Notch 62 Notch 64 Notch 66 Step 68 Step

Claims (6)

[Claims] 1. A canned motor in which a rotor and a stator are hermetically sealed by a rotor can and a stator can, respectively, a rotor shaft is surrounded and supported by a bearing, and a liquid for lubricating the bearing is circulated in a rotor chamber. And a rotating member fixed to the rotor shaft and facing the one end of the bearing inside the supporting member so as to come into contact with the supporting member. The supporting member and the rotating member face each other in the circumferential direction. A bearing monitor, characterized in that a required number of notches are provided in a portion to be formed, and when the bearing is worn, the respective members come into contact with each other to generate a vibration sound. 2. The bearings are arranged so as to respectively support both ends of a rotor shaft extending in the front and rear of the motor rotor, and the number of cutouts of a supporting member or a rotating member provided for these bearings is set to be different. The bearing monitor according to claim 1, wherein 3. The support member and the rotary member disposed in the support member so as to face the one end portion of the bearing so as to come into contact therewith are each provided with a step portion that can come into axial contact. Bearing monitor described in 2. 4. The bearing monitor according to claim 1, wherein the notches provided in the support member or the rotating member are provided with tooth-shaped notches at predetermined intervals in portions facing each other in the circumferential direction. 5. The bearing according to claim 1, wherein the supporting member for fixing the bearing is a bearing housing, and the rotating member arranged to be in contact with one end of the bearing is a thrust washer. monitor. 6. A vibrometer is provided in a part of the bearing housing to discriminate a bearing in a worn state and to quantitatively evaluate a worn state of the bearing by measuring a vibration characteristic. Bearing monitor.