JP2009063397A - Apparatus and method for inspecting state of bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for inspecting the state of a bearing capable of accurately and easily determining the state of a lubricant film in a rolling bearing in a non-contact state with a rotation-side ring or a rolling body when lubricant film thickness changes according to the temperature of the bearing and the rotational speed. <P>SOLUTION: In the method, calculated electrostatic capacity is obtained from a lubricant film thickness obtained by computation with a temperature and a rotational speed as parameters, and then, the lubrication state of a bearing is determined from comparison results of the calculated electrostatic capacity with an actually measured electrostatic capacity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing state inspection device and a bearing state inspection method for detecting a deterioration state of a lubricant inside a rolling bearing incorporated in a device such as a railway vehicle, an automobile, or an industrial machine.

In a rolling bearing, it is extremely important for the bearing life to check the internal lubrication state. When lubrication failure occurs and the thickness of the lubricant film formed by the lubricant formed between the rolling surface of the rolling element of the bearing and the raceway surface of the inner and outer rings becomes thinner than usual, the rolling surface and raceway surface are made of metal. It is known to cause contact and shorten the bearing life.
Therefore, it is desirable to observe the state of the lubricating film to predict the bearing life, but since it is impossible to directly observe the state of the lubricating film, various methods for measuring the state of the lubricating film have been proposed in the past. Has been. One method is to measure the state of the lubricating film as a DC resistance (Patent Document 1), and the other method is to measure the thickness of the lubricating film as an electric capacity (Patent Document 2).
Further, the applicant of the present application has proposed a method for estimating the state of the lubricating film of one bearing by measuring the electric capacity without contact.
JP 2001-311427 A JP 2003-214810 A

In the case of the method of measuring the state of the lubricating film as a DC resistance in Patent Document 1, since one of the inner and outer rings of the bearing is rotating, an electrical contact is required at a place other than the measured part, and the electrical resistance of the contact is There are problems that cause measurement errors and make measurement results unstable.
In the method of measuring the thickness of the lubricating film as the electric capacity in Patent Document 2, it is necessary to make a hole in the outer ring of the bearing and attach an electrode, which is not applicable to a general bearing.
In the above-described technique for measuring electric capacity without contact, the lubricating film thickness varies depending on the temperature and the rotational speed. Therefore, the lubricating state cannot be accurately determined only by detecting the electrostatic capacity.

  An object of the present invention is to accurately and easily change the state of a lubricating film in a rolling bearing in a non-contact state with respect to a rotating side wheel and a rolling element when the lubricating film thickness changes depending on the bearing temperature and rotational speed. A bearing state inspection device and a bearing state inspection method that can be determined are provided.

  The bearing condition inspection apparatus according to the present invention is a rolling bearing having a conductive outer ring, an inner ring, and a rolling element, respectively, and is provided with electrodes facing each other in a non-contact manner with a gap on the surface of the rotating side ring of the inner and outer rings. , Connected between the fixed side wheel of the inner and outer rings and the electrode, between the electrode and the rotating side wheel, between the rotating side wheel and the rolling element, and between the rolling element and the fixed side wheel. Capacitance measuring means for measuring the total value of the respective capacitances, temperature measuring means for measuring the temperature of the inner ring or outer ring, rotation speed measuring means for measuring the rotation speed of the rotating side wheel, and the temperature The temperature measured by the measuring means and the rotational speed measured by the rotational speed measuring means are set to derive the contact area and lubricating film thickness between the rolling element and the inner and outer rings, and the derived contact area and lubricating film Obtain the capacitance from the thickness, and obtain this Capacitance and, by comparing the total value of the capacitance measured by the capacitance measuring means, characterized by having a determining means for determining the lubrication condition of the rolling bearing.

According to this configuration, the capacitance measuring means includes the capacitance between the electrode and the rotating side wheel, the capacitance between the rotating side wheel and the rolling element, and between the rolling element and the fixed side wheel. The total value of each capacitance is measured. Further, the temperature measuring means measures the temperature of the inner ring or the outer ring, and the rotational speed measuring means measures the rotational speed of the rotating side wheel. The determination means sets the measured temperature, rotation speed, etc., derives the contact area and the lubrication film thickness between the rolling elements and the inner and outer rings, and the capacitance from the derived contact area and lubrication film thickness Ask for. Furthermore, the determination unit determines the lubrication state without using a complicated structure, processing, or the like by comparing the obtained capacitance with the total value of the measured capacitances.
In particular, using the temperature and rotation speed as parameters, the calculated capacitance is calculated from the lubricating film thickness obtained by calculation. From the comparison result between the calculated capacitance and the actually measured capacitance The lubrication state of the bearing can be accurately and easily determined. The determination means can be realized by a measuring instrument, a CPU, a simple electronic circuit that only compares with a threshold value, and the like.

  In the present invention, the determination means sets the temperature and rotational speed to be measured, and sets the viscosity and preload amount of the lubricant used in the bearing to derive the contact area and the lubricating film thickness. Also good. Although the lubrication state changes depending on the viscosity and preload amount of the lubricant, when the contact area and the lubrication film thickness are derived in consideration of the viscosity and preload amount of the lubricant, the lubrication state of the bearing is more accurately determined. be able to.

  In the present invention, the electrode may be a ring-shaped slip ring. In this case, a slip ring which is a general-purpose product can be applied, and the manufacturing cost can be reduced.

  An electrode facing the surface of the rotating side wheel of the inner and outer rings in a non-contact manner with a gap, an electrode electrically connected to the fixed side wheel, and an insulator electrically insulated between the electrodes. An integrated stationary unit may be attached to the stationary wheel. In this case, the assembly of the bearing state inspection device is facilitated, and the manufacturing cost can be reduced. Moreover, the electrode can separate the predetermined gap from the surface of the rotating side wheel only by attaching the fixed side unit to the fixed side wheel. In this case, adjustment and replacement of the fixed unit can be facilitated, and the number of work steps can be reduced.

  In the present invention, at least one of temperature measuring means for measuring the temperature of the inner ring or outer ring and rotational speed measuring means for measuring the rotational speed of the bearing may be provided integrally with the fixed side unit. In this case, the assembly of the bearing state inspection device can be further facilitated.

  The bearing state inspection method of the present invention is a bearing state inspection method for inspecting the lubrication state of a rolling bearing having a conductive outer ring, an inner ring and a rolling element, respectively, and a clearance is formed on the surface of the rotating side ring of the inner and outer rings. Provided with electrodes that are in contact with each other in a non-contact manner, connected between the fixed side wheel and the electrode of the inner and outer rings, and between the electrode and the rotation side wheel, between the rotation side wheel and the rolling element, And the total value of each capacitance between the rolling element and the fixed side wheel, the temperature of the inner ring or the outer ring, the rotational speed of the rotating side wheel, the measured temperature and the rotation The speed is set, the contact area between the rolling elements and the inner and outer rings and the lubricating film thickness are derived, the electrostatic capacity is obtained from the derived contact area and the lubricating film thickness, and the obtained capacitance and the measurement The total value of the respective capacitances And judging the state.

  According to this configuration, the calculated electrostatic capacity is obtained from the lubricating film thickness obtained by calculation using the temperature and the rotational speed as parameters, and the calculated electrostatic capacity and the actually measured electrostatic capacity are calculated. The lubrication state of the bearing can be accurately and easily determined from the comparison result. Thereby, it is possible to accurately determine the maintenance time of the apparatus, and it is possible to predict or detect an abnormality in the lubrication state of the lubricant.

  The bearing state inspection device of this invention is connected between the fixed side wheel of the inner and outer rings and the electrode, between the electrode and the rotation side wheel, between the rotation side wheel and the rolling element, and the rolling element. Capacitance measuring means for measuring the total value of each capacitance between the fixed side wheel, temperature measuring means for measuring the temperature of the inner ring or outer ring, and a rotational speed for measuring the rotational speed of the rotating side wheel By setting the measuring means, the temperature measured by the temperature measuring means, and the rotational speed measured by the rotational speed measuring means, the contact area between the rolling element and the inner and outer rings and the lubricating film thickness are derived and derived. The electrostatic capacity is obtained from the contact area and the lubricating film thickness, and the obtained electrostatic capacity is compared with the total value of each electrostatic capacity measured by the electrostatic capacity measuring means to lubricate the rolling bearing. Determination means for determining the state, In a state of non-contact with body, the state of the lubricating film in the rolling bearing can be determined accurately and easily when the bearing temperature, the lubricating film thickness by the rotating speed changes.

  An embodiment of the present invention will be described with reference to FIGS. This embodiment is applied to, for example, a bearing state inspection device that detects a deterioration state of a lubricant inside a rolling bearing incorporated in a device such as a railway vehicle, an automobile, a two-wheeled vehicle, an industrial machine, or a machine tool. However, it is not limited to the said apparatus. The following description also includes a description of the bearing condition inspection method.

The case of inner ring rotation will be described.
This bearing state inspection device determines the lubrication state of the lubricating film of the rolling bearing 2 in the bearing using device 1 in which the rolling bearing is attached to the rotating shaft. The bearing state inspection device includes a capacitance measuring unit 3, a temperature sensor 4 as a temperature measuring unit, a rotation sensor 5 as a rotational speed measuring unit, and a determination unit 6 to be described later.
The rolling bearing 2 is formed on an outer ring 7 that is a fixed side wheel, an inner ring 8 that is a rotating side wheel that is fitted to a rotation shaft, a raceway surface 7 a that is formed on the inner peripheral surface of the outer ring 7, and an outer peripheral surface of the inner ring 8. And a plurality of rolling elements 9 interposed between the raceway surfaces 8a. The rolling bearing 2 in this case is a ball bearing in which the rolling elements are balls.

  When the rolling bearing 2 rotates normally, that is, when the inner ring rotates, a lubricating film, that is, an oil film having a thickness of 1 μm or less is formed on the contact surface between the outer ring 7 and the rolling element 9. It is known that the load is transmitted through the lubricating film 10 without being in direct contact. A similar lubricating film 11 is also formed on the contact surface between the inner ring 8 and the rolling element 9. Here, when the lubricating film 10 is considered as a dielectric and the outer ring 7 and the rolling element 9 are considered as electrodes, one capacitor 12 is formed here. Similarly, another capacitor 13 is formed in the relationship between the inner ring 8, the rolling elements 9, and the lubricating film 11.

This is schematically expressed as a circuit configuration in which two capacitors Ca and Cb are connected in series as shown in FIG. Assuming that the number of rolling elements per bearing is n and the electrostatic capacities of the respective rolling elements 9 are equal, the case where the capacitors Ca and Cb having the same electrostatic capacity are connected in parallel is considered. Assuming that the electrostatic capacity Cc per moving body is given, the electrostatic capacity C and the electrostatic capacity Cc of the entire bearing are expressed as follows.
C = n · Cc (1)
Cc = Ca · Cb / (Ca + Cb) (2)

Therefore, if the capacitance of the path from the outer ring 7 to the inner ring 8 is measured, the capacitance Cc at one location can be estimated.
Further, when the lubrication film thicknesses between the outer ring 7 and the rolling elements 9 and between the rolling elements 9 and the inner ring 8 are da ′ and db ′, the contact ellipse areas are Sa ′ and Sb ′, and the dielectric constant is ε, the rolling elements Capacitances Ca and Cb per piece are expressed by the following equations (3) and (4).
Ca = εSa ′ / da ′ (3)
Cb = εSb ′ / db ′ (4)

The lubricating film thickness varies depending on the influence of the bearing load, rotation speed, lubricant, and the like. In the present embodiment, the lubricant film thickness can be estimated by obtaining the relationship between the lubricant film thickness and the capacitance in advance using the elastohydrodynamic lubrication theory, that is, the EHL theory.
Specifically, in the EHL theory, the viscosity of the lubricant to be used, the number of rotations used, the amount of preload (load), and the temperature range are set, the contact area between the rolling element 9 and the outer ring 7 and the inner ring 8, and the lubricating film thickness. Is derived. By substituting the obtained contact area and lubricating film thickness into the above formulas (3) and (4), the capacitances Ca and Cb per rolling element are obtained.

The lubrication state of the rolling bearing is determined by comparing the obtained capacitances Ca and Cb with the measured capacitance. Moreover, it becomes possible to estimate the lubricating film thickness by substituting the actually measured capacitance value into the above formulas (3) and (4).
Specifically, as shown in FIG. 4, the calculated value indicated by the solid line L1 is compared with the actual sensor output, and if the difference between the sensor output and the calculated value is small, it is determined that the bearing is operating normally. To do. That is, the dotted lines L2 and L3 serve as threshold values, and if there is a sensor output between these dotted lines L2 and L3, it is determined that the bearing is operating normally.
If the sensor output is above the dotted line L2, it is determined that the lubricating film thickness is thin. In this case, there is a possibility that the inner and outer rings and the ball come into contact with each other, and there is a possibility that foreign matter is mixed in the bearing. If the sensor output is below the dotted line L3, it is determined that the lubricating film thickness is thick. In this case, foreign matter may have entered the bearing.

As the capacitance measuring means 3 for measuring the capacitance described above, for example, a commercially available measuring instrument such as a capacitance meter may be applied. When necessary, this measuring instrument is electrically connected to the electrode 14 and the outer ring 7 provided with a predetermined gap δ on the end face of the inner ring, which is a rotating side wheel, for measurement. The electrode 14 is realized by, for example, a slip ring. Note that the capacitance may be constantly measured using the capacitance measuring means 3 dedicated to the bearing.
Of the above-described lubricant viscosity, rotational speed, amount of preload, and temperature range, the rotational speed used is measured by a rotation sensor 5 as a rotational speed measuring means of the bearing state inspection device. The temperature range is measured by a temperature sensor 4 or the like as temperature measuring means of the bearing state inspection apparatus.

  The determination means 6 is realized by, for example, a measuring instrument, a central processing unit (abbreviated as CPU: Central Processing Unit), or the like, or a simple electronic circuit, for example, a circuit that only compares with a threshold value. When a measuring instrument such as a commercially available electric capacity meter is applied, this measuring instrument can be used for measuring the lubrication state of the rolling bearing of the example, and the combined use of the measuring instrument itself can be improved. Therefore, the initial introduction cost of the bearing state inspection device can be suppressed as much as possible. When a dedicated electronic circuit or the like is applied, the lubrication state of the rolling bearing can always be determined, and the deterioration state of the lubricant can be monitored in real time. The determination unit 6 and the capacitance measuring unit 3 may be provided integrally or separately.

  FIG. 3 is a diagram illustrating the relationship between the rotation speed and the capacitance. In the figure, the solid line represents the calculated value of the capacitance using the EHL theory, and the black square plot represents the measured value of the capacitance value in consideration of the rotational speed and the like. As the number of rotations of the bearing increases, the calculated value and the actually measured value gradually decrease in capacitance and substantially coincide. From the relationship between the calculated value and the actually measured value, it can be estimated that the calculated capacitance value using the EHL theory is correct.

  According to the bearing condition inspection apparatus described above, in particular, the calculated electrostatic capacity is obtained from the lubricating film thickness obtained by calculation using the temperature and rotational speed as parameters. From the result of comparison with the measured capacitance, the lubrication state of the bearing can be determined accurately and easily. Although the lubrication state changes depending on the viscosity and preload amount of the lubricant, the determination means 6 derives the contact area and the lubrication film thickness in consideration of the viscosity and preload amount of the lubricant. It is possible to more accurately determine the lubrication state. By such a bearing state inspection device and a bearing state inspection method, it is possible to accurately determine the maintenance time of the device, and it is possible to predict or detect an abnormality in the lubrication state of the lubricant.

  Next, another embodiment of the present invention will be described with reference to FIGS. In the following description, parts corresponding to the matters described in the preceding embodiments are denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

In the present embodiment, a ring-shaped detection ring 15 that is opposed to the surface of the rotating side wheel with a predetermined gap δ is provided, and the capacitance between the detection ring 15 and the fixed side wheel is measured, thereby making contactless. The electrostatic capacity of the bearing can be measured. Instead of the detection ring 15, a non-ring-shaped detection body may be provided on the surface of the rotating side wheel with a gap δ.
The operation principle and the like will be described with reference to the inner ring rotation bearing shown in FIG. As shown in the figure, a detection ring 15 that faces the side surface of the inner ring 8 of the rolling bearing with a gap δ therebetween, and one electrode 3a is electrically connected to the detection ring 15, and an outer ring 7 that is a fixed side ring. The other electrode 3b is electrically connected.

  In this case, the outer ring 7 which is a fixed side wheel is appropriately insulated by an insulating means (not shown), and is not electrically connected to other members such as a housing. An electrical equivalent circuit of a path extending from the bearing using device to the detection ring 15 in this case is as shown in FIG. 7, for example. That is, the electric circuit in this case is formed by the path from the electrode 3b of the capacitance measuring means 3 to the outer ring 7 of the bearing → the rolling element 9 → the inner ring 8 → the detection ring 15 → the electrode 3a of the capacitance measuring means 3. . When the rolling bearing of the bearing using device is an outer ring rotating, an electrical equivalent circuit of a path extending from the bearing device to the detection ring 15 is, for example, as shown in FIG. That is, the electric circuit in this case is a path from one electrode 3a of the capacitance measuring means 3 to the detection ring 15 → the outer ring 7 of the bearing → the rolling element 9 → the inner ring 8 → the other electrode 3b of the capacitance measuring means 3. Formed with. Compared with the equivalent circuit of FIG. 6, this equivalent circuit is the same in the overall capacitance C only by changing the position of the capacitance Cr from the inner ring 8 side to the outer ring 7 side.

A capacitor is formed between the inner ring 8 and the detection ring 15, and the electrostatic capacity Cr of the capacitor Cr is defined as S and the distance between the rings is d.
Cr = εS / d (5)
It becomes. The value of the capacitance Cr can be measured in advance. In addition, the capacitance Cc per rolling element is
Cc = C · Cr / n (C-Cr) (6)
From this equation (6), the electrostatic capacity Cc per rolling element can be obtained.

  For example, a measuring instrument such as a capacitance meter can be used to measure the entire capacitance. However, as described above, since the parameter of the lubricating film thickness includes the temperature and the rotational speed, the temperature sensor 4 is attached to the stationary side wheel to measure the temperature of the stationary side wheel or the rotational side wheel of the bearing. The rotation sensor 5 is attached to the fixed side wheel, and the rotational speed of the bearing is measured. The lubricating film thickness is estimated from each output. Thus, by obtaining the capacitance based on the lubricating film thickness and the like including the temperature and the number of revolutions as parameters, and comparing the obtained capacitance with the capacitance measured by the measuring instrument, The lubrication state of the rolling bearing can be determined accurately and easily.

  FIG. 9 is a cross-sectional view showing a main part of a bearing state inspection device and the like according to still another embodiment of the present invention. In the present embodiment, the bearing state inspection apparatus includes an electrode 14 provided on the end surface of the inner ring, which is a rotating side wheel, with a predetermined gap δ, an electrode 31 that is electrically connected to the outer ring 7, and a space between these electrodes 14, 31. The fixed side unit 33 is provided integrally with the insulator 32 that is electrically insulated. For example, the fixed unit 33 is fitted to a fitting hole Ha of the rolling bearing 2 in the housing H in a unit fitting hole Hb formed through a step portion, and is attached to the outer ring 7 which is a fixed side wheel. .

  Of the fixed-side unit 33, the electrode 31 disposed on the radially outer side is fitted into the unit fitting hole Hb, and is fixed to the end surface of the outer ring to be electrically connected. The insulator 32 fixed to the inner periphery of the electrode 31 is made of, for example, resin, and is provided on the outer ring end face with an axial gap so as not to interfere with the outer ring end face. However, the insulator material is not limited to resin. The electrode 14 is fixed to the inner periphery of the insulator 32. The other configuration is the same as that of the embodiment shown in FIG.

When the fixed side unit 33 shown in FIG. 9 is provided, the assembly of the bearing state inspection device is facilitated, and the manufacturing cost can be reduced. Moreover, the electrode 14 can separate the predetermined gap δ from the inner ring end face only by attaching the fixed side unit 33 as described above. In this case, adjustment and replacement of the fixed side unit 33 can be facilitated, and the number of work steps can be reduced. Other operations and effects similar to those of the embodiment shown in FIG.
Further, as indicated by a two-dot chain line in FIG. 9, at least one or both of the temperature sensor 4 and the rotation sensor 5 may be provided integrally with the fixed unit 33. In this case, the assembly of the bearing state inspection device can be further facilitated.

FIG. 10 is a block diagram illustrating an example of a determination unit in the bearing state inspection apparatus.
The determination unit 6 includes a CPU 16 that estimates the lubrication state of the rolling bearing from the measurement value measured by the capacitance measurement unit 3. The capacitance measuring means 3 includes an oscillator 17 and a current measuring means 18 connected in series, and the current measuring means 18 and the CPU 16 are electrically connected. Further, the current measuring means 18 is electrically connected to the electrode 3a, and the oscillator 17 is electrically connected to the electrode 3b. An example will be shown in which an alternating current is passed through this bearing-using device, whereby the above-described overall capacitance C is converted into an impedance and measured. In this case, the average capacitance Ca can also be obtained from the measured impedance.

FIG. 11 shows an oscillator 20 in which the capacitance measuring means 3A is composed of an OP amplifier 19 and a frequency corresponding capacity estimating means 21 for estimating the capacitance from the oscillation frequency of the oscillator 20, and the measured frequency of the oscillator 20 is measured. Shows an example in which the electrostatic capacity C of the entire bearing using device is estimated. The oscillator 20 in this case is called a relaxation oscillator and is configured by connecting resistors 30Ra, 30Rb, 30Rt, and a capacitor 30Ct to the OP amplifier 19. When the resistance values of the resistors 30Ra, 30Rb, and 30Rt are Ra, Rb, and Rt, and the capacitance of the capacitor 30Ct is Ct, the oscillation frequency f is approximately f = 1 / (2Rt Ct).
It is known that
Here, the capacitance C of the oscillator 20 is estimated by replacing the capacitor 30Ct with the capacitance C of the entire bearing using device.

It is explanatory drawing which shows the test | inspection of the rolling bearing using the bearing state inspection apparatus which concerns on one Embodiment of this invention. It is a schematic diagram at the time of expressing the bearing structure of the rolling bearing as an electric circuit. It is a figure showing the relationship between a rotation speed and an electrostatic capacitance. It is a figure showing the relationship between a rotation speed and an electrostatic capacitance, and explaining whether a bearing is operating normally by threshold value judgment. It is a figure showing the structure which provided the slip ring in the inner ring | wheel which is a rotation side wheel among the rolling bearings using the bearing state inspection apparatus which concerns on other embodiment of this invention through the clearance gap. It is a figure showing the structure which provided the slip ring in the outer ring which is a rotation side wheel among the rolling bearings at intervals. It is an electrical equivalent circuit schematic of the path | route from one electrode to the other electrode. It is an equivalent circuit schematic of other embodiment of this invention. It is sectional drawing showing principal parts, such as a bearing state inspection apparatus which concerns on further another embodiment of this invention. It is a block diagram showing an example of the determination means in a bearing state inspection apparatus. It is a block diagram showing the other example of a determination means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Rolling bearing 3 ... Capacitance measuring means 4 ... Temperature sensor 5 ... Rotation sensor 6 ... Determination means 7 ... Outer ring 8 ... Inner ring 9 ... Rolling body 14 ... Electrode 15 ... Detection ring 33 ... Fixed side unit delta ... Clearance

Claims (6)

In rolling bearings having conductive outer rings, inner rings and rolling elements,
An electrode is provided on the surface of the rotating side wheel of the inner and outer rings that is opposed to the surface of the rotating side wheel in a non-contact manner. The electrode and the rotating side wheel are connected between the fixed side wheel and the electrode of the inner and outer rings. , Capacitance measuring means for measuring the total value of each capacitance between the rotating side wheel and the rolling element, and between the rolling element and the fixed side wheel,
Temperature measuring means for measuring the temperature of the inner ring or the outer ring,
A rotational speed measuring means for measuring the rotational speed of the rotating side wheel;
By setting the temperature measured by the temperature measuring means and the rotational speed measured by the rotational speed measuring means, the contact area between the rolling element and the inner and outer rings and the lubricating film thickness are derived, and the derived contact area and An electrostatic capacity is obtained from the lubricating film thickness, and the obtained electrostatic capacity is compared with the total value of each electrostatic capacity measured by the electrostatic capacity measuring means to determine the lubrication state of the rolling bearing. A determination means;
A bearing state inspection device characterized by comprising:   2. The determination means according to claim 1, wherein the determination means sets the temperature and rotation speed to be measured, and sets the viscosity and preload amount of the lubricant used in the bearing to derive the contact area and the lubricating film thickness. Bearing condition inspection device.   3. The bearing state inspection device according to claim 1, wherein the electrode is a ring-shaped slip ring.   3. The electrode according to claim 1 or 2, wherein the surface of the rotating side wheel of the inner and outer rings is opposed to the surface of the rotating side wheel in a non-contact manner, the electrode electrically connected to the fixed side wheel, and the electrical contact between these electrodes. A bearing state inspection device in which a stationary unit integrated with an insulator insulated by a motor is attached to the stationary wheel.   5. The method according to claim 4, wherein at least one of temperature measuring means for measuring the temperature of the inner ring or outer ring and rotation speed measuring means for measuring the rotation speed of the bearing is provided integrally with the fixed side unit. Bearing condition inspection device In a bearing state inspection method for inspecting the lubrication state of a rolling bearing having a conductive outer ring, an inner ring, and rolling elements, respectively.
An electrode is provided on the surface of the rotating side wheel of the inner and outer rings that is opposed to the surface of the rotating side wheel in a non-contact manner. The electrode and the rotating side wheel are connected between the fixed side wheel and the electrode of the inner and outer rings. , The total value of each electrostatic capacitance between the rotating side wheel and the rolling element, and between the rolling element and the fixed side wheel,
Measuring the temperature of the inner ring or outer ring,
Measure the rotational speed of the rotating side wheel,
The measured temperature and rotational speed were set, the contact area and the lubrication film thickness between the rolling elements and the inner and outer rings were derived, and the capacitance was obtained from the derived contact area and the lubrication film thickness. A bearing state inspection method for comparing a capacitance and a total value of the measured capacitances to determine a lubrication state of the rolling bearing.

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