JP4942496B2 - Bearing state inspection device and bearing state inspection method - Google Patents

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 either the bearing inner or outer ring is rotating, an electrical contact such as a slip ring is required in a place other than the measured part. There is a problem that the electrical resistance of this causes a measurement error and makes the measurement result 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.

The above-described technique for measuring electric capacity without contact has the following problems.
・ It is difficult to adjust and install the gap between the fixed ring and the measuring ring.
-Since the fixed ring and other members such as the housing are electrically non-conductive, the gap length between the fixed ring and other members such as the housing when other members such as the housing are conductive Therefore, it is necessary to interpose a non-conductive member so that the measurement does not affect the measurement.
-Electrodes must be attached to the bearing ring and electrically connected to the detection circuit, making assembly difficult.

  An object of the present invention is to estimate 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, and measure an oil film thickness and the like without using an electrical contact such as a slip ring. It is an object of the present invention to provide a bearing state inspection device and a bearing state inspection method that can be easily performed, and that the entire apparatus can be easily assembled.

  The bearing state inspection device according to the present invention is a rolling bearing having a conductive outer ring, an inner ring, and a rolling element, respectively, and is electrically conductive and electrically connected to the rotating side wheel attached to the rotating side wheel of the inner and outer rings. A rotation-side capacitive coupling body and a stationary-side unit attached to a stationary-side wheel of the inner and outer rings, and the stationary-side unit is connected to the rotation-side capacitive coupling body via a gap for generating capacitance. A fixed-side capacitive coupling body that is opposed to and electrically non-conductive to the fixed-side wheel, and is electrically insulated from the fixed-side capacitive coupling body and electrically connected to the fixed-side wheel. And a connecting electrode member.

  According to this configuration, the fixed side unit includes the fixed side capacitive coupling body and the connection electrode member. Of these, the fixed-side capacitive coupling body is opposed to the rotating-side capacitive coupling body via a gap for generating capacitance, and is electrically non-conductive to the fixed-side wheel. The connection electrode member is electrically insulated from the fixed-side capacitive coupling body and electrically connected to the fixed-side wheel. In particular, since the rotating-side capacitive coupling body and the fixed-side capacitive coupling body are opposed to each other through a gap for generating capacitance, a terminal of a determination unit such as a capacitance meter is used without using an electrical contact such as a slip ring. Both can be connected to the fixed side and the oil film thickness of the lubricant can be measured. In addition, since it is possible to detect the lubrication state by simply attaching the fixed unit and the rotary capacitive coupling to the rolling bearing, it is easy to assemble the inspection device, and calibration before attaching the bearing to the device. It becomes possible to do.

  In this invention, it is connected between the fixed-side capacitive coupling body and the connection electrode member, between the rotating-side capacitive coupling body and the fixed-side capacitive coupling body, between the rotating-side wheel and the rolling element, and A determination means may be provided that measures the total value of the electrostatic capacities between the fixed side wheel and the rolling element and determines the lubrication state of the rolling bearing from the measured value.

In this case, the determination means is configured such that the capacitance between the rotating side capacitive coupling body and the fixed side capacitive coupling body, the capacitance between the rotating side wheel and the rolling element in a non-conduction state, and the non-conduction state. The total value of the electrostatic capacitance between a certain fixed side wheel and the rolling element is measured, and the lubrication state is determined from this measured value. This determination means can be realized by a measuring instrument, a CPU (Central Processing Unit), or a simple electronic circuit (a circuit that only compares with a threshold value).
When a measuring instrument such as a commercially available capacitance meter is applied, this measuring instrument can be used for measuring the lubrication state of other rolling bearings, 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.

Before Symbol rotation-side capacitive coupling body and the fixed capacitive coupling member are each rotary ring and the stationary ring is a ring-shaped member and a fixed ring and these rotating ring, which is opposed in the radial direction or the axial direction. In this case, the rotating ring and the fixed ring can be designed and attached based on the diameter and the like of the rotating side wheel and the fixed side wheel.

Are those before Symbol rotating ring and a stationary ring is positioned on the side of the rolling bearing, the annular of the rotation-side capacitive coupling member and the stationary unit, for mounting to be fitted to each rotation-side wheel and the stationary ring It has a fitting part . In this case, the rotation-side capacitive coupling body can be easily attached to the rotation-side wheel by the annular fitting portion. Further, the fixed side unit can be easily attached to the fixed side wheel by the annular fitting portion. In addition, each annular fitting portion can increase the positioning accuracy of the rotating side capacitive coupling body with respect to the rotating side wheel, and can increase the positioning accuracy of the fixed side capacitive coupling body with respect to the stationary side wheel.

  In this invention, the rotating side wheel is an inner ring, and the fixed side unit is overlapped in order from the outer diameter side to the inner diameter surface of the housing on the side of the outer ring, with the housing fitted to the outer diameter surface of the outer ring. It may consist of a ring-shaped connecting electrode member provided in a state, a ring-shaped insulator, and a fixing ring. In this case, since the fixed unit is configured by a ring-shaped member overlapping the inner diameter surface of the housing from the outer diameter side, handling and assembly of the fixed unit can be facilitated, and the number of work steps can be reduced.

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. Install the rotation-side capacitive coupling member is a rotating ring of a ring-shaped electrically conductive member which is electrically conductive with respect to the fixed side wheel of said inner and outer rings, electrostatically to the rotation-side capacitive coupling body a solid Jogawa capacitive coupling member is a fixing ring comprising a ring-shaped member of electrically non-conductive with respect to the radial direction or the axial direction in pairs Muko said stationary wheel via a gap for capacitance generation, the fixed A connecting electrode member electrically insulated from the side capacitive coupling and electrically connected to the fixed side wheel is attached , and the rotating ring and the fixed ring are positioned at the side of the rolling bearing. The rotation-side capacity Coalescence and the connecting electrode member has a fitting portion of the annular mounting for fitting to the respective rotation-side wheel and the stationary ring,
Between the front Symbol rotation-side capacitive coupling member and the fixed capacitive coupling body between the rotation-side ring and the rolling element, and the total value of the capacitance between the fixed-side ring and the rolling element, the fixed-side Measurement is performed by connecting a connecting means between the capacitive coupling body and the connection electrode member, and the lubrication state of the rolling bearing is determined from the measured value.

  According to this configuration, the fixed-side capacitive coupling body is opposed to the rotating-side capacitive coupling body via the gap for generating capacitance, and is electrically non-conductive to the fixed-side wheel. The connection electrode member is electrically insulated from the fixed-side capacitive coupling body and electrically connected to the fixed-side wheel. A measuring means is connected between the fixed-side capacitive coupling body and the connection electrode member, and the capacitance between the rotational-side capacitive coupling body and the stationary-side capacitive coupling body, The total value of the electrostatic capacitance between the rolling elements and each electrostatic capacitance between the stationary side wheel and the rolling elements in a non-conducting state is measured. The lubrication state is determined from this measured value. In particular, the fixed-side capacitive coupling body faces the rotating-side capacitive coupling body through a gap for generating capacitance, so that both terminals of the measuring means are on the fixed side without using electrical contacts such as slip rings. By connecting, the oil film thickness of the lubricant can be measured. Thus, the lubrication state can be determined by measuring the total value of the respective capacitances. Therefore, the state of the lubricating film in the rolling bearing can be estimated in a non-contact state with respect to the rotating side wheel and the rolling element, and the oil film thickness and the like can be easily measured without using an electrical contact such as a slip ring. Therefore, the entire apparatus can be easily assembled.

In the bearing state inspection device according to the present invention, since the rotating side capacitive coupling body and the fixed side capacitive coupling body are opposed to each other through a gap for generating capacitance, the electrical capacitance can be obtained without using an electrical contact such as a slip ring. By connecting both terminals of determination means such as a meter to the fixed side, the oil film thickness of the lubricant can be measured. Also the rolling bearing, just attaching a fixed-side unit and the rotation-side capacitive coupling body, that Do is possible to detect the lubrication, that the rotation-side capacitive coupling body and the fixed capacitive coupling body, respectively ring A rotating ring and a fixing ring, which are members of the above, wherein the rotating ring and the fixing ring are opposed to each other in a radial direction or an axial direction, and the rotating ring and the fixing ring are located on a side portion of the rolling bearing, The rotation-side capacitive coupling body and the fixed-side unit each have an annular fitting portion for attachment that is fitted to the rotation-side wheel and the fixed-side wheel, respectively. For this reason, the assembly of the inspection apparatus becomes easy, it is possible to calibrate before mounting the bearing device. Therefore, the state of the lubricating film in the rolling bearing can be estimated in a non-contact state with respect to the rotating side wheel and the rolling element, and the oil film thickness and the like can be easily measured without using an electrical contact such as a slip ring. Therefore, the entire apparatus can be easily assembled .
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. A rotating-side capacitive coupling body, which is a rotating ring made of a conductive ring-shaped member that is electrically conductive with respect to the rotating-side capacitive coupling body, is attached to the stationary-side ring of the inner and outer rings. A fixed-side capacitive coupling body that is a fixed ring formed of a ring-shaped member that is opposed to the fixed-side wheel in a radial direction or an axial direction through a generation gap, and the fixed-side capacitive coupling A connecting electrode member that is electrically insulated from the body and electrically connected to the fixed side wheel is mounted, and the rotating ring and the fixed ring are positioned on the side of the rolling bearing. , Rotation side capacity The combined electrode member and the connecting electrode member each have an annular fitting portion for mounting to be fitted to the rotating side wheel and the fixed side wheel, respectively, and rotate between the rotating side capacitive coupling body and the fixed side capacitive coupling body. A connection means is connected between the fixed-side capacitive coupling body and the connection electrode member for the total value of the capacitances between the side wheel and the rolling element and between the fixed-side wheel and the rolling element. The lubrication state of the rolling bearing is determined from the measured value. Therefore, it is possible to estimate the state of the lubricating film in the rolling bearing in a non-contact state with respect to the rotating side wheel and the rolling element, and easily measure the oil film thickness and the like without using an electrical contact such as a slip ring. And the assembly of the entire apparatus can be easily performed.

  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.

  As shown in FIG. 1, the bearing condition inspection apparatus 1 </ b> A estimates the lubrication state of the lubricating film of the rolling bearing 1 in a bearing using apparatus in which the rolling bearing 1 is attached to the rotary shaft 7. The rolling bearing 1 is formed on an outer ring 2 that is a fixed side wheel, an inner ring 3 that is a rotating side wheel that fits the rotating shaft 7, a raceway surface formed on the inner peripheral surface of the outer ring 2, and an outer peripheral surface of the inner ring 3. A plurality of rolling elements 6 interposed between the raceway surfaces, a cage 5 for holding the rolling elements 6, and a seal 4 provided at one end of the bearing. The rolling bearing 1 in this case is a ball bearing in which the rolling elements 6 are balls.

  The bearing state inspection apparatus 1A includes a conductive rotating ring 8 attached to the inner ring 3 that is a rotating side wheel and electrically connected to the inner ring 3, and a fixed side that is attached to the outer ring 2 that is a fixed side wheel. Unit 13. Further, the bearing state inspection apparatus 1A includes a determination unit 16 described later. The fixed side unit 13 is a housing that faces the rotating ring 8 via a gap δr for generating capacitance and is electrically non-conductive with the outer ring 2 and is fitted to the outer diameter surface of the outer ring 2. 10, a metal member 12 which is a connecting electrode member electrically insulated from the fixing ring 8 and electrically connected to the outer ring 2, and an insulator which electrically insulates the fixing ring 9 and the metal member 12. 11. The rotating ring 8 corresponds to a rotating side capacitive coupling body, and the fixed ring 9 corresponds to a fixed side capacitive coupling body. The fixing ring 9 is fixed to the inner peripheral surface of the insulator 11 so as to be parallel to the rotating ring 8 through a constant radial gap δr, that is, an annular gap δr. The fixing ring 9 and the rotating ring 8 are disposed to face each other in the radial direction.

  The outer ring 2 is fitted to the inner peripheral surface 10 b of the housing 10, and the end surface of the outer ring 2 comes into contact with the step portion 10 a of the housing 10. Most of the metal member 12 is fitted to the inner peripheral surface of the stepped portion 10a. The metal member 12 is a conductive member having conductivity that is electrically connected to the outer ring 2, and has a large diameter portion 12 a that constitutes a large portion of the metal member 12, and a large diameter portion that is smaller in diameter than the large diameter portion 12 a. A small-diameter portion 12b extending a predetermined small distance from one axial end portion of 12a toward the bearing inner side. The large diameter portion 12a and the small diameter portion 12b are integrally formed. A stepped portion between the large-diameter portion 12a and the small-diameter portion 12b and forming a radial plane faces the abutment surface of the outer ring 2 and comes into contact therewith. The outer diameter surface of the small diameter portion 12b is fitted to the inner peripheral surface of the outer ring shoulder diameter. The inner peripheral surface 10 b of the housing 10 and the small-diameter portion 12 b of the metal member 12 correspond to an annular fitting portion for attachment that is fitted to the outer ring 2.

  An insulator 11 that electrically insulates the fixing ring 9 and the metal member 12 is fitted to the inner peripheral surface of the metal member 12. The insulator 11 has an insulator large diameter portion 11 a fitted to the large diameter portion 12 a of the metal member 12 and an insulator small diameter portion 11 b fitted to the small diameter portion 12 b of the metal member 12. The insulator large diameter portion 11a and the insulator small diameter portion 11b are integrally formed. One side step portion 11c forming a radial plane between the insulator large diameter portion 11a and the insulator small diameter portion 11b faces the other step portion 12d of the metal member 12 and comes into contact therewith. As a result, the insulator 11 is positioned in the axial direction relative to the metal member 12. These step portions 11c and 12d can surely prevent the insulator 11 from entering the interior more undesirably than a predetermined position inside the bearing.

  A fixing ring 9 is fitted to the inner peripheral surface of the insulator 11. The fixing ring 9 has a large-diameter ring portion 9a fitted to the insulator large-diameter portion 11a and a small-diameter ring portion 9b fitted to the insulator small-diameter portion 11b. The large-diameter ring portion 9a and the small-diameter ring portion 9b are integrally formed. A step portion 9c forming a radial plane between the large-diameter ring portion 9a and the small-diameter ring portion 9b faces and contacts the other-side step portion 11d of the insulator 11. Thereby, the fixing ring 9 is positioned in the axial direction relative to the insulator 11. By these step portions 9c and 11d, it is possible to reliably prevent the fixing ring 9 from entering the interior more undesirably than a predetermined position inside the bearing. The inner diameter of the large-diameter ring portion 9a and the inner diameter of the small-diameter ring portion 9b are formed to have the same diameter, that is, without a step.

  The rotating ring 8 has a ring body 8a and a fitting portion 8b. A fitting portion 8 b is integrally attached to one end of the ring body 8 a in the axial direction, and this fitting portion 8 b is fitted to the shield shoulder portion of the inner ring 3. That is, the fitting portion 8 b enters the bearing and is fixed to the inner ring 3. The fitting portion 8b corresponds to an annular fitting portion for attachment that is fitted to the inner ring 3. Further, the end portion of the ring main body 8 a facing the inner ring end face comes into contact with the end face of the inner ring 3. As a result, the axial position of the fitting portion 8b is restricted, and the fitting portion 8b is prevented from undesirably entering the bearing.

  FIG. 3A is a half sectional view of the rolling bearing, and FIG. 3B is a schematic diagram expressing the bearing structure of FIG. 3A as an electric circuit. In FIG. 3A, when the rolling bearing 1 is rotating normally, a lubricating film (oil film) having a thickness of 1 μm or less is formed on the contact surface between the outer ring 2 and the rolling element 6, and the outer ring 2 and the rolling element. 6 is known to transmit a load through a lubricating film without direct contact. A similar lubricating film is also formed on the contact surface between the inner ring 3 and the rolling element 6. In the relationship between the outer ring 2 and the rolling element 6, when the lubricating film is considered as a dielectric and the outer ring 2 and the rolling element 6 are considered as electrodes, one capacitor is formed here. Similarly, another capacitor is formed in the relationship between the inner ring 3 and the rolling elements 6.

  When this is schematically expressed, a circuit configuration in which two capacitors 17 and 18 are connected in series as shown in FIG. Here, assuming that the capacitances Ca and Cb of the capacitors 17 and 18 are equal, the total capacitance of the two capacitors 17 and 18 is Ca / 2. Also, assuming that the number of rolling elements 6 per bearing is n and the capacitances of the capacitors in each rolling element 6 are equal, it is regarded as a circuit configuration in which capacitors having the same capacitance are connected in parallel. Therefore, the total capacitance of one bearing is nCa / 2. Therefore, if the capacitance of the path from the outer ring 2 to the inner ring 3 in the rolling bearing 1 is measured, the capacitance Ca at one lubricating film 19 (20) can be estimated. However, as it is, either of the inner and outer rings 3 and 2 is rotating (in the case of FIG. 1, the inner ring 3 is rotating). As in the case of the method, an electrical contact such as a slip ring is required at a portion other than the measurement location, which causes a measurement error and a measurement result becoming unstable.

  Therefore, in the bearing state inspection apparatus 1A of this embodiment, the capacitor formed by the rotating ring 8 and the fixed ring 9 and the contact point between the inner and outer rings 3 and 2 of the rolling bearing 1 and the rolling element 6 are formed. The total value with the capacity is estimated in a non-contact manner by measuring the metal member 12 as an electrode, and the lubrication state of the oil film of the rolling bearing 1 is inspected from the change in the capacity. In the present embodiment, an electrical equivalent circuit of a path extending from one electrode 21 to the other electrode 22 is as shown in FIG. That is, the electric circuit in this case is formed by the path of electrode 21 → metal member 12 → outer ring 2 → rolling element 6 → inner ring 3 → rotating ring 8 → fixing ring 9 → electrode 22.

A capacitor is formed between the fixed ring 9 and the rotating ring 8, and the electrostatic capacity Cr is expressed by a ring cross-sectional area S, a distance d between the fixed ring and the rotating ring, and a dielectric constant ε.
Cr = εS / d (1)
It becomes. The value of the capacitance Cr can be measured in advance.
On the other hand, if the capacitance of the capacitor formed between each rolling element 6 and the inner and outer rings 3 and 2 is the same value Ca, the overall capacitance Cj on the bearing side is:
Cj = nCa / 2 (2)
And
Ca = 2Cj / n (3)
It becomes.
Further, since the capacitance of the capacitor between the fixed ring 9 and the rotating ring 8 is Cr, if the entire capacitance C of the equivalent circuit is measured,
C = Cj · Cr / (Cj + Cr) (4)
Than,
Cj = C · Cr / (C−Cr) (5)
It becomes. Therefore, from equations (3) and (5),
Ca = 2C · Cr / n (C—Cr) (6)
As a result, the average capacitance Ca per location of the lubricating films 20 and 19 interposed between the rolling element 6 and the inner and outer rings 3 and 2 can be obtained. For measurement of the entire capacitance C, a commercially available measuring instrument such as a capacitance meter may be used to connect and measure this measuring instrument when necessary, and a person may make a determination.

The determination means 16 is electrically connected between the metal member 12 and the fixing ring 9, and includes, for example, a measuring instrument, a central processing unit (abbreviated as CPU: Central Processing Unit), a simple electronic circuit, For example, it is realized by a circuit that only compares with a threshold.
When a measuring instrument such as a commercially available capacitance meter is applied, this measuring instrument can be used for measuring the lubrication state of other rolling bearings, 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 means 16 measures the entire electrostatic capacity C as described above, and measures the lubrication state of the rolling bearing 1 from the measured value. As a criterion for determining the lubrication state of the rolling bearing 1 by the determination means 16, for example, the following lubrication state can be cited.

1. When the oil film of the rolling bearing is not formed, the conductive state is established, and the overall capacitance increases only with Cr.
2. When any one of the oil film forming portions of the rolling bearing is out of the oil film, the portion becomes conductive, so that the entire capacitance is slightly increased.
3. When an excessive load is applied to the bearing using device, the thickness of the oil film is reduced, so that the overall capacitance increases.
4). When the oil film state in the rolling bearing becomes unstable, the electrostatic capacity becomes unstable, so the fluctuation of the electrostatic capacity is checked.

When these determination criteria are adopted, the determination unit 16 determines that the measured value of the overall capacitance C has increased more than usual (when a predetermined threshold value has been exceeded), or if the variation in capacitance is large. It is determined that the lubrication state is defective (when the fluctuation range of the capacitance exceeds a predetermined threshold value) or when both conditions are satisfied.
When the rolling bearing 1 is stopped or rotating at a low speed, the rolling bearing 1 is in a conductive state or a state close thereto. As in the case of, the overall capacitance increases only with Cr.

  In the bearing state inspection apparatus 1A of this embodiment, the total value of the electrostatic capacitances between the rotating ring 8 and the fixed ring 9, between the inner ring 3 and the rolling element 6, and between the outer ring 2 and the rolling element 6. However, it is measured in a non-contact state with the inner ring 3 and the rolling elements 6 that are the rotation side wheels, and the quality of the lubrication state of the rolling bearing 1 is determined from the measured values.

  In particular, since the rotating ring 8 and the fixed ring 9 are opposed to each other through a gap δr for generating capacitance, both the one and other terminals of the determination means 16 are connected without using an electrical contact such as a slip ring. By connecting to the fixed side, the oil film thickness of the lubricant can be measured. Further, since the lubrication state can be detected simply by attaching the fixed side unit 13 and the rotating ring to the rolling bearing 1, the assembly of the bearing state inspection apparatus 1A is facilitated, and before the bearing is attached to the apparatus. Can be calibrated.

When a measuring instrument such as a commercially available capacitance meter is applied as the determination means 16, this measuring instrument can be used for measuring the lubrication state of other rolling bearings, 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 as the determination means 16, the lubrication state of the rolling bearing can always be determined, and the deterioration state of the lubricant can be monitored in real time.
In addition, the rotating ring 8 and the fixing ring 9 are opposed to each other in the radial direction. In this case, the rotating ring 8 and the fixing ring 9 are designed based on the diameter dimensions of the inner ring 3 and the outer ring 2 and attached. It can be made possible.

  The rotating ring 8 and the fixed ring 9 are located on the side of the rolling bearing 1, that is, one end in the axial direction, and the rotating ring 8 and the fixed side unit 13 are fitted to the inner ring 3 and the outer ring 2, respectively. Having an annular fitting portion 8b and an inner peripheral surface 10b. Therefore, the rotating ring 8 can be easily attached to the inner ring 3 by the annular fitting portion 8b, and the fixed side unit 13 can be easily attached to the outer ring 2 by the inner peripheral surface 10b. In addition, the fitting portion 8 b and the inner peripheral surface 10 b can increase the positioning accuracy of the rotating ring 8 with respect to the inner ring 3 and can increase the positioning accuracy of the fixed ring 9 with respect to the outer ring 2.

Further, the housing 10 in which the fixed side unit 13 is fitted to the outer diameter surface of the outer ring 2, and a ring-shaped metal member provided in an overlapping state in order from the outer diameter side on the inner diameter surface of the housing 10 on the side of the outer ring 2. 12, the ring-shaped insulator 11 and the fixed ring 9 make it easy to handle and assemble the fixed-side unit 13 and reduce the number of work steps.
In addition, since the conductive fixing ring 9 attached to the outer ring 2 which is the stationary side wheel is provided in the rotating ring 8 attached to the inner ring 3 via the gap δr, in particular, between the rotating ring 8 and the fixing ring 9. Capacitance adjustment can be made easier than in the prior art, and each capacitance can be measured with high accuracy. Further, since the total value of each capacitance can be measured through the fixed ring 9 and the rotating ring 8, the trouble of directly attaching the electrode to the fixed side ring of the bearing can be omitted, and the assembly of the inspection apparatus itself is simplified. It becomes possible.

  Further, in the bearing using device and the bearing state inspection method incorporating the bearing state inspection device 1A, the lubrication film state and load state of the rolling bearing 1 can be monitored. It is possible to notify that the bearing using device 1A needs to be stopped or the bearing needs to be replaced. When this bearing using apparatus 1A is a railway vehicle or an industrial machine, safety is improved. Moreover, in this bearing using apparatus 1A, since the lifetime of a rolling bearing 1 and a secular change can be estimated, the useless replacement | exchange of the rolling bearing 1 or the replacement delayed is eliminated, and economical efficiency improves.

FIG. 5 shows another embodiment of the present invention.
In the following description, the same reference numerals are given to portions corresponding to the matters described in the preceding forms in each embodiment, and overlapping 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.

  The bearing state inspection apparatus 1B of this embodiment is configured by causing a part of the rotating ring 8A and a part of the fixed ring 9A to face each other in the axial direction. In the embodiment shown in FIG. 1 described above, the inner diameter of the fixing ring 9 is formed without a step, but the fixing ring 9A of this embodiment is formed such that one end portion in the axial direction protrudes radially inward. ing. This protrusion is referred to as an inner flange 9Aa. On the other hand, one axial end portion of the rotating ring 8A constitutes an outer flange 8Aa protruding outward in the radial direction. The inner flange 9Aa is fixed to the inner peripheral surface of the insulator 11 so as to be parallel to the outer flange 8Aa via a certain axial gap δa. The other configuration is the same as that of the embodiment of FIG. According to the bearing state inspection apparatus 1B of this embodiment, the conductive fixing ring 9A attached to the outer ring 2 which is the stationary side wheel is provided on the rotating ring 8A attached to the inner ring 3 via the axial gap δa. In particular, the adjustment of the capacitance between the rotating ring 8A and the fixed ring 9A can be made easier than the above-described conventional technique, and each capacitance can be measured with high accuracy. In addition, since the total value of each capacitance can be measured via the fixed ring 9A and the rotating ring 8A, the trouble of directly attaching the electrode to the fixed side ring of the bearing can be omitted, and the assembly of the inspection apparatus itself is simplified. It becomes possible. Other effects similar to those of the embodiment of FIG.

  FIG. 6 is an equivalent circuit diagram of still another embodiment of the present invention. The bearing state inspection apparatus of this embodiment is applied when the rolling bearing of the bearing using apparatus in FIG. The inner ring 3 of this rolling bearing is fitted to a fixed shaft. A ring-shaped metal member 12A, which is a conductive member, is attached to the end surface of the inner ring 3, and a fixing ring 9B is fitted to the outer peripheral surface of the metal member 12A via an insulator. The rotating ring 8B is attached to the end face of the outer ring 2, and the fixed ring 9B and the rotating ring 8B are disposed to face each other in the radial direction.

  However, these rings 9B and 8B may be arranged facing each other in the axial direction. The electric circuit in this case is formed by a path of electrode 22 → metal member 12A → inner ring 3 → rolling element 6 → outer ring 2 → rotating ring 8B → fixing ring 9B → electrode 21. Also in the bearing state inspection apparatus of this embodiment, the total value of each electrostatic capacitance between the rotating ring 8B and the fixed ring 9B, between the inner ring 3 and the rolling element 6, and between the outer ring 2 and the rolling element 6 is the same. Measured in a non-contact state with the outer ring 2 and the rolling element 6 that are the rotation side wheels, and the quality of the lubrication state of the rolling bearing is determined from the measured value. Other operations and effects similar to those of the embodiment of FIG. As described above, the bearing state inspection device can be applied even when the rolling bearing is rotating the outer ring.

FIG. 7 is a block diagram illustrating an example of a determination unit in the bearing state inspection apparatus.
The determination unit 16 includes a capacitance measurement unit 23 and a CPU 24 that estimates the lubrication state of the rolling bearing from the measurement value measured by the capacitance measurement unit 23. Among these, the capacitance measuring means 23 includes an oscillator 25 and a current measuring means 26 connected in series, and the current measuring means 26 and the CPU 24 are electrically connected. Further, the current measuring means 26 is electrically connected to the electrode 21, and the oscillator 25 is electrically connected to the electrode 22. 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.
Since the electrostatic capacitance formed by the oil film is generally as small as several tens of pF, when the oscillation frequency of the oscillator 25 is set to, for example, about 100 kHz to 10 MHz in this embodiment, high detection accuracy can be obtained.

FIG. 8 shows an oscillator 28 in which the capacitance measuring means 23A is composed of an OP amplifier 27 and a frequency corresponding capacity estimating means 29 for estimating the capacitance from the oscillation frequency of the oscillator 28. The example which estimated the electrostatic capacitance C of the whole bearing using apparatus with a frequency is shown. The oscillator 28 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 27. 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 is estimated by replacing the capacitor 30Ct of the oscillator 28 with the capacitance C of the entire bearing using device.

It is explanatory drawing which shows the test | inspection of the rolling bearing in the bearing using apparatus using the bearing state inspection apparatus which concerns on one Embodiment of this invention. It is an important section expanded sectional view of the bearing state inspection device. (A) is a half sectional view of a rolling bearing, and (B) is a schematic view when the bearing structure of (A) is expressed as an electric circuit. It is an electrical equivalent circuit schematic of the path | route from one electrode to the other electrode. It is a principal part expanded sectional view of the bearing state inspection apparatus which concerns on other embodiment of this invention, and made the rotating ring and the fixed ring face the axial direction. It is the equivalent circuit schematic of 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 1A ... Bearing condition inspection apparatus 1 ... Rolling bearing 2 ... Outer ring 3 ... Inner ring 6 ... Rolling body 8 ... Rotating ring 9 ... Fixed ring 10 ... Housing 11 ... Insulator 12 ... Metal member 13 ... Fixed side unit 16 ... Determination means δr ... Gap

Claims (4)

In rolling bearings having conductive outer rings, inner rings and rolling elements,
A conductive rotation-side capacitive coupling body that is attached to the rotation-side wheel of the inner and outer rings and is electrically connected to the rotation-side wheel; and a fixed-side unit that is attached to the fixed-side wheel of the inner and outer rings. Prepared,
The fixed-side unit is opposed to the rotating-side capacitive coupling body through a gap for generating capacitance, and is electrically non-conductive to the fixed-side wheel, and the fixed-side capacitive coupling. A connecting electrode member that is electrically insulated from the body and electrically connected to the fixed-side wheel, and the rotating-side capacitive coupling body and the fixed-side capacitive coupling body are respectively ring-shaped members. A rotating ring and a fixed ring, wherein the rotating ring and the fixed ring are opposed to each other in a radial direction or an axial direction, and the rotating ring and the fixed ring are located on a side portion of the rolling bearing, A bearing state inspection device , wherein the side capacitive coupling body and the fixed side unit have an annular fitting portion for attachment to be fitted to the rotating side wheel and the fixed side wheel, respectively .   In Claim 1, it is connected between the fixed side capacitive coupling body and the connection electrode member, between the rotation side capacitive coupling body and the fixed side capacitive coupling body, between the rotation side wheel and the rolling element, And a bearing state inspection device provided with a determination means for measuring the total value of each capacitance between the fixed side wheel and the rolling element and determining the lubrication state of the rolling bearing from the measured value. 3. The rotating wheel according to claim 1 , wherein the rotating side wheel is an inner ring, the stationary side unit is fitted to an outer diameter surface of the outer ring, and an outer surface of the outer ring is disposed outside the inner diameter surface of the housing. A bearing state inspection device comprising a ring-shaped connecting electrode member, a ring-shaped insulator, and a fixed ring provided in an overlapping state in order from the radial side. 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.
The rotation-side wheel of the inner and outer rings, mounted electrically conductive with the rotation-side capacitive coupling member is a conductive rotating ring of the ring-shaped member against the rotating race member, one of said inner and outer rings the stationary ring, a ring-shaped member of electrically non-conductive in the radial direction or axial direction relative to the pair Muko said stationary wheel via a gap for capacitance generated in the rotation-side capacitive coupling body a solid Jogawa capacitive coupling member is a fixing ring, attached to the connecting electrode member which is electrically conductive with respect to an electrically insulated and the stationary ring relative to the fixed-side capacitive coupling member, said rotating ring And the fixed ring is located on the side of the rolling bearing, and the rotating-side capacitive coupling body and the connecting electrode member are attached to the rotating-side wheel and the fixed-side wheel, respectively. Have joints,
Between the front Symbol rotation-side capacitive coupling member and the fixed capacitive coupling body between the rotation-side ring and the rolling element, and the total value of the capacitance between the fixed-side ring and the rolling element, the fixed-side A bearing state inspection method in which a connection means is connected between a capacitive coupling body and the connection electrode member, and the lubrication state of the rolling bearing is determined from the measured value.

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