JPH087142Y2 - Bearing wear monitoring device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for monitoring wear of slide bearings, particularly sealed slide bearings in canned motor pumps and the like.

[0002]

2. Description of the Related Art Generally, a canned motor pump has a rotating portion completely disposed in a liquid to be handled, and therefore has no shaft-sealing portion, so that it is completely leak-free and is widely used as a pump for various processes. However, in such a canned motor pump, the radial and thrust loads of the rotating part during operation are all applied to the slide bearing that supports the rotating shaft of the rotating part. Due to the fact that it is located at the end, a special monitoring device is provided for this type of bearing and is arranged to monitor its wear.

A brief explanation of such a monitoring device will be given below. This type of monitoring device is generally constructed mechanically or electrically. First, the mechanical structure is constructed by providing an end nut at the end of a canned motor shaft supported by a plain bearing, and providing a sensing part of a detection part in the hollow part of the end nut. Here, the inside of the sensing unit is hermetically sealed, and when the bearing wears in the radial direction, the shaft generates whirling motion, while when the bearing wears in the thrust direction, the shaft is displaced in the axial direction. However, the sensing portion contacts the inner wall or the end surface of the hollow portion and destroys it, whereby the internal pressure of the sensing portion changes and the radial or thrust limit wear of the bearing is detected. Next, the electrical structure is constituted by, for example, connecting and burying a plurality of magnetic flux detecting coils in series in the stator, and when the bearing wears, the shaft and the motor rotate eccentrically. The electromotive force generated therein increases and the degree of wear is detected.

[0004]

However, all of the above-mentioned conventional bearing wear monitoring devices have the following difficulties or problems.

That is, although the mechanical structure can detect both the radial wear and the thrust wear of the bearing, these detections are all related to the limit wear, and the degree of wear until reaching the limit wear, In other words, no remaining life could be detected. On the other hand, in the case of the electrical structure, the degree of wear of the bearing is detected, but this detection is limited to only the radial direction, and nothing can be detected in the thrust direction.

Further, in this type of bearing wear monitoring device, it is preferable to detect the thrust direction and which bearing is worn, but
None of these detections is possible with the conventional device.

Therefore, an object of the present invention is to provide a bearing wear monitoring device capable of simultaneously detecting the radial and thrust wear levels of each bearing and also detecting the thrust direction.

[0008]

In order to achieve the above object, a bearing wear monitoring device according to the present invention has a cone bearing a central axis with respect to a rotary shaft supported by a plain bearing. It is characterized in that a trapezoidal detection section and a non-contact displacement sensor corresponding to the detection section and measuring a distance from the detection section are provided. In this case, the detection unit may be formed of a truncated cone or a symmetrical truncated cone in which two truncated cones face each other.

[0009]

The distance between the detection unit and the displacement sensor when the rotary shaft rotates is output from the displacement sensor as an electric signal. This output signal changes when the bearing wears and the distance changes. It changes with the amount. Therefore, the bearing wear degree can be monitored by detecting the output signal.

That is, first, when the bearing wears in the radial direction, the rotating shaft swirls around the inner circumference of the bearing, and therefore the distance between the detecting portion and the displacement sensor changes periodically, and the output signal becomes sinusoidal. , And the amplitude of this sine wave increases in proportion to the degree of wear of the bearing. Therefore, the magnitude of the amplitude of the output signal can be used as the degree of radial wear of the bearing. Next, when the bearing wears in the thrust direction,
The rotating shaft moves in the axial direction, and therefore the detecting unit on the rotating shaft also moves in the axial direction. In this case, since the detecting unit is formed in a truncated cone shape, the average distance between the detecting unit and the displacement sensor changes. That is, the average value of the output signal changes. Therefore,
The degree of change in the average value of the output signal can be used as the degree of wear of the bearing in the thrust direction. It should be noted that bearing wear generally proceeds simultaneously in both radial and thrust directions, so that in this case the output signal changes in relation to the degree of wear in both directions. In this case, the magnitude of the amplitude (wear in the radial direction) is smaller than that in the case of wear only in the radial direction, so it is necessary to correct it in accordance with the wear in the thrust direction (change in average value). There is.

Next, the monitoring unit consisting of the detection unit and the displacement sensor can usually be provided for both bearings, and in this case, the frustoconical inclination direction of the detection unit can be set to any direction. Normally, when the bearing is worn in the thrust direction, the distance between the bearing and the displacement sensor is shortened. Therefore, in this case, it is possible to easily detect that the thrust is acting in the direction of the bearing on the side where the average value of the output signal is large, that is, the direction of the thrust. If it is clear that only one of the two bearings will wear mainly in the radial direction, the monitoring unit will use a symmetric conical shape in which the detection unit has two truncated cones facing each other, as will be described later. By forming the bearing on the base, it is possible to similarly monitor the radial wear degree of the bearing and the thrust wear degree of both bearings by providing only one bearing on the wear side.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the bearing wear monitoring device according to the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1, the monitoring device of the present invention is applied to a canned motor pump. The structure of the canned motor pump will be briefly described first. The canned motor pump includes a pump portion 10 and a motor portion. 1
2, and the rotary shaft 14 of the pump is arranged in a liquid-tight space defined by both ends 16 and 18 of the motor part 12 and the can 20, and the both ends are sleeves 22 and 24.
Via rear bearings 26 and 28, respectively.

However, in the monitoring device of the present invention,
The rotary shaft 14 supported by the first (rear) and second (front) bearings 26, 28 is disposed via the frames 30, 32 so as to share a central axis with respect to the rotary shaft 14. Frustoconical detectors 34, 36 and the detectors 34, 3
Corresponding to No. 6, monitoring units 42 and 44 including non-contact displacement sensors 38 and 40 arranged outside the can 20 are provided. The monitoring units 42 and 44 are shown in FIG.
As shown in an enlarged view in (b) (here, (a) is a double bearing 2
6 and 28 show a state when not worn, (b) shows the second bearing 2
8 shows the state when it is worn, but a description thereof will be described in detail later), the detecting portions 34 and 36 thereof are formed in a truncated cone, and the inclination directions of the truncated cones 34 and 36 are the bearings 26, 36. When 28 wears in the thrust direction, the peak height is set in a direction in which the distance between the bearings and the sensors 38 and 40 is shortened with respect to the bearings, that is, the direction opposite to the bearings 26 and 28. The inclination direction can be set in the opposite direction. Then, when the rotary shaft 14 rotates, the truncated cones 34 and 36 and the sensors 38 and 4 corresponding thereto.
The distance to 0 is output as the magnitude of the electric signal from the sensors 38 and 40, respectively.

Next, the operation of the monitoring apparatus of the present invention having such a structure will be described. First, in a state where both the first and second bearings 26 and 28 are not worn (FIG. 2 (a)), the rotary shaft 14 is thrust in the radial direction (axial direction) as shown in FIG. Since it is stably rotated at a predetermined position even in the
The output signals from 0 are substantially flat reference average values fn and f as shown in (a) and (b) of FIG. 5, respectively.
It is output as n. Next, when the second bearing 28 is worn in the radial direction, the rotary shaft 14 causes the inner circumference of the bearing 28 to have a radial wear degree (amount of eccentricity) as shown in FIG.
Since the distance between the truncated cone 36 and the displacement sensor 40 is periodically changed by swinging by yr, the radial direction output signal fr from the displacement sensor 40 is as shown in (b) of FIG. It becomes a sine wave of amplitude xr centered on the reference average value fn. However, since the amplitude xr increases in proportion to the wear degree, the magnitude of the amplitude xr can be used as the wear degree yr. The output signal of the first monitoring unit 42 regarding the first bearing 26 that is not worn is maintained at the reference average value fn as shown in FIG. Further, in the figure, reference symbol T indicates a rotation cycle. Next, the second bearing 2
When 8 is worn in the thrust direction, the rotary shaft 14 becomes
As shown in FIG. 2 (b), only the degree of wear in the thrust direction (displacement amount) yt moves axially to the right in the figure, and therefore both truncated cones 34, 36 also move in the same manner. The average distance between 36 and the respective displacement sensors 38, 40 respectively corresponding thereto is long for the first monitoring part 42 while being short for the second monitoring part 44. Therefore, the thrust direction output signals ft and ft in both the monitoring units 42 and 44 are, as shown in FIGS. 7A and 7B, respectively, the monitoring unit 42 by the displacement xt with respect to the reference average value fn. , And the monitor 44 increases. However, since the thrust direction acts in the direction of the monitoring unit 44 in which the output signal ft increases, it is detected that the bearing 28 is worn, and at the same time, the displacement xt increases in proportion to the wear degree yt. Therefore, the wear degree y of the bearing 28 is determined by the magnitude of the displacement xt.
can be t. Next, when the second bearing 28 is worn in both the radial direction and the thrust direction, the thrust direction output signal ft is the same as in FIG. 7B, as shown in FIG. 8B. Although output as an average output value that is larger than the average value fn by a displacement xt, the radial direction output signal fr 'becomes a sine wave with an amplitude xr' centered on the thrust direction output signal ft. The amplitude xr 'is proportional to the radial wear degree yr, but in proportion to the radial wear only, that is, in FIG.
It becomes smaller than the amplitude xr in (b). Therefore, in this case, the radial wear degree yr is corrected with respect to the thrust wear degree yt (displacement xt), and this correction will be described with reference to the measurement display device described below.

That is, in FIG. 9 for explaining the measurement system, the output signals 50 of the first and second monitoring sections 42 and 44 are shown.
And 52 are amplitudes 54 and 56 and average values 58 and 58, respectively.
60, and the amplitudes 54, 56 are corrected in the calculators 62, 64 with respect to the corresponding average values 58, 60, respectively, and then the radials of the first and second bearings 26, 28 are displayed on the indicators 66, 68. The average value 58, 60 is compared with the average value 58, 60 in the comparator 70 and compared with the average value 58, 60, and the thrust direction and the thrust direction wear of the worn bearing are displayed on the indicators 72, 74. Displayed as degrees. That is, the case shown in FIG. 8 described above will be specifically described.
The radial wear degree of the bearing 26 is 0, and the radial wear degree yr (amplitude xr) of the second bearing 28 is displayed on the display 68.
However, the comparator 72 has a thrust direction (direction of the bearing 28).
However, the indicator 74 indicates that the bearing 28 has a wear degree yt in the thrust direction.
(Displacement xt) is displayed respectively.

In the above description, one bearing 2
Although only 8 has been described, it is clear that similar operation is achieved if the other bearing 26, 28 or even both bearings 26, 28 are worn. Therefore, description of these is omitted.

As described above, according to the present invention, it is possible to simultaneously detect the radial and thrust wear of each bearing in both directions, and simultaneously detect the thrust direction. Further, since the device of the present invention is composed of only two units, the detection unit and the displacement sensor, there is an advantage that the structure is simple.

Next, FIG. 10 shows another embodiment of the monitoring device according to the present invention. In this embodiment, in the case where it is clear in advance that only one of the two bearings will be mainly worn in the radial direction, it is necessary to provide the monitoring portion only in one of the bearings so that It is configured so that the degree of wear and the degree of wear in the thrust direction of both bearings can be monitored simultaneously. That is, in the above-described embodiment, the monitoring unit 80 is provided only for the one bearing 28,
The detecting section 82 of the monitoring section 80 is formed as a symmetrical truncated cone with two truncated cones facing each other, and is displaced so as to face the central trough of the symmetrical truncated cone 82 when not worn. A sensor 44 is provided. Therefore,
When the bearing 28 is worn in the thrust direction, the symmetrical truncated cone 82 is worn in the direction of the bearing 28 as shown in FIG. 11, and when the bearing 26 (not shown) is worn in the thrust direction.
As shown in FIG. 3, the bearings 26 are moved in the respective directions, but in any case, since the truncated cone 82 is formed symmetrically, the truncated cone 82 and the displacement sensor 44 are formed.
The distance between and is shortened in proportion to the amount of movement of the symmetrical truncated cone 82, that is, the degree of radial wear. Therefore, when the measurement display device is configured to detect the output signal 84 of the monitoring unit 80 as the amplitude 86 and the average value 88 as shown in FIG. 13, the bearing on the worn side having the average value 88 (for example, in FIG. 11). Indicates the degree of wear yt in the thrust direction of the bearing 28) on the indicator 94, while the amplitude 86 is corrected in the calculator 92 with respect to the average value 88, and then the bearing 28
The wear degree (amplitude) in the radial direction can be displayed on the display 94. Even in this case, instead of the symmetric truncated cone 82, the same truncated cone 36 as in the above-described embodiment is used.
Can also be used.

The present invention has been described above with reference to the preferred embodiments, but the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit thereof.

[0021]

As described above, the bearing wear monitoring device according to the present invention has a truncated cone-shaped detecting portion that shares a central axis with respect to a rotary shaft supported by a slide bearing. Since the non-contact displacement sensor that measures the distance from the detection unit corresponding to the detection unit is provided, the distance between the detection unit and the displacement sensor is, when the bearing wears,
In this case, whether the wear is in the radial direction or the thrust direction is proportional to the degree of the wear, so that the wear degree in both the radial direction and the thrust direction of each bearing, which was conventionally difficult, can be easily and simultaneously achieved. Can be detected. Further, it is possible to detect the thrust direction through the conical inclined surface of the detection unit. In addition, the device of the present invention has an advantage that it can be provided easily and at low cost because it is composed of a detection unit and a displacement sensor, each of which is a single unit.

[Brief description of drawings]

FIG. 1 is an overall sectional view showing an embodiment in which a bearing wear monitoring device according to the present invention is applied to a canned motor pump.

2 is a partially enlarged view of the monitoring unit in FIG. 1, (a)
Shows a state where both front and rear bearings are not worn, and (b) shows a state where the front (second) bearing in both bearings is worn.

FIG. 3 is an enlarged cross-sectional view of a rotating shaft and a bearing, showing a state in which the bearing is not worn in the radial direction.

FIG. 4 is an enlarged cross-sectional view similar to FIG. 3, showing a state of the bearing during radial wear.

FIG. 5 is an output signal diagram, in which (a) relates to a rear bearing when not worn, and (b) relates to a front bearing when not worn.

FIG. 6 is an output signal diagram, in which (a) relates to a rear bearing when not worn, and (b) relates to a front bearing when worn in the radial direction.

FIG. 7 is an output signal diagram, in which (a) relates to a rear bearing when not worn, and (b) relates to a front bearing when worn in the radial direction.

FIG. 8 is an output signal diagram in which (a) relates to a rear bearing when not worn, and (b) relates to a front bearing when worn in both radial and thrust directions.

9 is a system diagram illustrating a measurement display device in the bearing wear monitoring device shown in FIG.

10 is a partially enlarged view showing another embodiment of the bearing wear monitoring device according to the present invention, in which the monitoring device is applied to the rear bearing in the canned motor pump shown in FIG. 1. FIG.

11 is an enlarged view of the same part as FIG. 10, showing a state when the rear bearing is worn in the thrust direction.

FIG. 12 is a partially enlarged view similar to FIGS. 10 and 11, showing a state when the front bearing is worn in the thrust direction.

13 is a system diagram illustrating a measurement display device in the bearing wear monitoring device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Pump part 12 ... Motor part 14 ... Rotating shafts 16, 18 ... End part 20 ... Can 22,24 ... Sleeve 26 ... Rear slide bearing 28 ... Front slide bearing bearing 30, 32 Frame 34, 36 ... Detection section (conical detection section) 38, 40 ... Non-contact displacement sensor 42, 44 ... Monitoring section 50, 52 ... Output signal 54, 56 Amplitude 58, 60 ... Average value 62, 64 ... Computing unit 66, 68 ... Bearing Radial wear indicator 70 ... Comparator 72 ... Rotor shaft thrust direction indicator 74 ... Bearing thrust wear indicator 80 ... Monitoring unit 82 ... Frustum-shaped detection unit (symmetrical truncated cone detection) 84) Output signal 86 ... Amplitude 88 ... Average value 90 ... Bearing thrust direction wear indicator 92 ... Calculator 94 ... Bearing radial direction wear degree

Claims (3)

[Scope of utility model registration request] 1. A rotary shaft supported by a slide bearing,
A bearing wear monitoring device comprising: a truncated cone-shaped detection unit that shares a central axis with respect to the rotation axis; and a non-contact displacement sensor that corresponds to the detection unit and measures a distance from the detection unit. 2. The bearing wear monitoring device according to claim 1, wherein the detector is a truncated cone. 3. The bearing wear monitoring device according to claim 1, wherein the detection section is a symmetrical truncated cone in which two truncated cones face each other.