JP2020148217A - Rolling bearing and rolling bearing with sensor - Google Patents

Abstract

To provide a rolling bearing which can easily constitute a sensor capable of detecting the state of the rolling bearing.SOLUTION: A rolling bearing includes: an inner ring; an outer ring which is arranged outside the inner ring; a rolling element which is arranged between the inner ring and the outer ring; a cage which is arranged between the inner ring and the outer ring and holds the rolling element; a first electrode and a second electrode which are formed of a conductive material; and insulation films which are formed on surfaces of the first electrode and the second electrode. One of the rolling element and the cage becomes a third electrode. A first distance which is a distance between the first electrode and the third electrode and a second distance which is a distance between the second electrode and the third electrode change accompanying relative rotation of the inner ring with respect to the outer ring. A time change of the first distance accompanying the relative rotation of the inner ring with respect to the outer ring is shifted in phase from a time change of the second distance accompanying relative rotation of the inner ring with respect to the outer ring.SELECTED DRAWING: Figure 1

Description

The present invention relates to rolling bearings and rolling bearings with sensors.

Patent Document 1 (Japanese Unexamined Patent Publication No. 2008-019933) describes a bearing system. The bearing system described in Patent Document 1 includes a rolling bearing, a first sensor, and a second sensor. The first sensor is a sensor that detects the rotation speed of the rotating wheel, and the second sensor is a sensor that detects the revolution speed of the cage or the rolling element.

Other bearing systems including rolling bearings and sensors include the bearing system described in Patent Document 2 (Japanese Patent Laid-Open No. 2017-160974) and the bearing described in Patent Document 3 (Japanese Patent Laid-Open No. 2018-038692). There is a system.

Japanese Unexamined Patent Publication No. 2008-019933 JP-A-2017-160974 Japanese Unexamined Patent Publication No. 2018-038692

In the bearing system described in Patent Documents 1 to 3, it is necessary to externally attach a sensor such as a magnetic sensitive element to the rolling bearing. Therefore, in the bearing system described in Patent Documents 1 to 3, there is a concern that the system configuration may be complicated.

The present invention has been made in view of the above-mentioned problems of the prior art. More specifically, the present invention provides a rolling bearing capable of easily configuring a sensor capable of detecting the state of the rolling bearing.

The rolling bearing according to one aspect of the present invention is arranged between the inner ring, the outer ring arranged outside the inner ring, the rolling element arranged between the inner ring and the outer ring, and between the inner ring and the outer ring. It includes a cage for holding the rolling element, a first electrode and a second electrode formed of a conductive material, and an insulating film formed on the surfaces of the first electrode and the second electrode. One of the rolling element and the cage is a third electrode. The first distance, which is the distance between the first electrode and the third electrode, and the second distance, which is the distance between the second electrode and the third electrode, change with the relative rotation of the inner ring with respect to the outer ring. The time change of the first distance due to the relative rotation of the inner ring with respect to the outer ring is out of phase with the time change of the second distance due to the relative rotation of the inner ring with respect to the outer ring.

In the rolling bearing according to one aspect of the present invention, when the first distance becomes small, a positive charge is induced in the first electrode and a negative charge is induced in the second electrode. When the first distance is increased, a current flows from the first electrode to the second electrode due to the electric charge induced in each electrode. Further, in the rolling bearing according to one aspect of the present invention, when the second distance becomes small, a negative charge is induced in the first electrode and a positive charge is induced in the second electrode. When the second distance is increased, a current flows from the second electrode to the first electrode due to the electric charge induced in each electrode. In the rolling bearing according to one aspect of the present invention, since the operating state of the rolling bearing can be determined by using the above current, a sensor capable of detecting the state can be configured with a simple configuration.

In the above rolling bearing, the rolling element may be a ball. The cage may be a third electrode. The cage may have a convex portion protruding along the central axis direction in the portion holding the rolling element. In the above rolling bearing, the rolling elements may be arranged at equal intervals along the circumferential direction. The number of the first electrode and the number of the second electrode may be an integral multiple of the number of rolling elements, respectively. The first electrode and the second electrode may be alternately arranged at equal intervals along the circumferential direction.

In the above rolling bearing, the cage may be a third electrode. A convex portion protruding toward the first electrode may be formed on the surface of the cage facing the first electrode. In the above rolling bearing, the protrusions may be arranged at equal intervals along the circumferential direction. The number of the first electrode and the second electrode may be an integral multiple of the number of convex portions, respectively. The first electrode and the second electrode may be alternately arranged at equal intervals along the circumferential direction.

The rolling bearing may further include a sealing member that defines a bearing space between the inner ring and the outer ring. The first electrode and the second electrode may be arranged on the surface of the seal member on the bearing space side.

In the above rolling bearing, the insulating film may be a polytetrafluoroethylene (PTFE) film. In the above rolling bearing, the thickness of the insulating film may be 100 μm or less.

The rolling bearing with a sensor according to one aspect of the present invention includes the above-mentioned rolling bearing and a detection unit that detects the revolution speed of the cage based on the voltage between the first electrode and the second electrode. In the above-mentioned rolling bearing with a sensor, the detection unit may be configured so that the relative rotation speed of the inner ring with respect to the outer ring can be estimated based on the revolution speed of the cage.

The rolling bearing with a sensor according to another aspect of the present invention detects the state of the rolling bearing and the lubricant supplied to the inside of the rolling bearing based on the voltage between the first electrode and the second electrode. It has a part. In the above-mentioned rolling bearing with a sensor, the state of the lubricant detected by the detection unit may be the water content in the lubricant.

According to the rolling bearing according to one aspect of the present invention, a sensor capable of detecting the state of the rolling bearing can be easily configured.

It is a top view of the rolling bearing 10. It is sectional drawing in II-II of FIG. It is sectional drawing in III-III of FIG. It is an enlarged view in the region IV of FIG. It is an enlarged view in the region V of FIG. It is 1st explanatory drawing for demonstrating the effect of a rolling bearing 10. It is a 2nd explanatory drawing for demonstrating the effect of a rolling bearing 10. It is a 3rd explanatory drawing for demonstrating the effect of a rolling bearing 10. It is a 4th explanatory drawing for demonstrating the effect of a rolling bearing 10. It is a schematic graph which shows the relationship between the voltage between electrodes and the revolution speed of a cage 14. 6 is a schematic graph showing the relationship between the relative rotation speed of the inner ring 11 with respect to the outer ring 12 and the revolution speed of the cage 14. It is a top view of the rolling bearing 10A. 9 is a cross-sectional view taken along the line XX of FIG. It is sectional drawing in XI-XI of FIG. It is a top view of the rolling bearing 20. It is sectional drawing in XIII-XIII of FIG. It is sectional drawing in XIV-XIV of FIG. It is an enlarged view in the region XV of FIG. It is an enlarged view in the region XVI of FIG. It is a bottom view of the rolling bearing 20A. It is sectional drawing in XVIII-XVIII of FIG. It is sectional drawing in XIX-XIX of FIG. It is a top view of the rolling bearing 30. It is sectional drawing in XXI-XXI of FIG. It is sectional drawing in XXII-XXII of FIG. It is sectional drawing of the rolling bearing 40. It is sectional drawing of the rolling bearing 40 in the state that the inner member 41 is rotated relative to the outer member 42. It is a block diagram of a power generation apparatus 100. It is a block diagram of the rolling bearing 200 with a sensor.

The details of the embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts shall be designated by the same reference numerals, and duplicate explanations shall not be repeated.

(First Embodiment)
The configuration of the rolling bearing (hereinafter referred to as "rolling bearing 10") according to the first embodiment will be described below.

FIG. 1 is a top view of the rolling bearing 10. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. As shown in FIGS. 1 to 3, the rolling bearing 10 is a cylindrical roller bearing. The rolling bearing 10 includes an inner ring 11, an outer ring 12, a rolling element 13, a cage 14, a first electrode 15, a second electrode 16, an insulating film 17 and an insulating film 18 (specifically, FIG. 4 and FIG. (See FIG. 5).

The inner ring 11 has an annular (ring-shaped) shape. The inner ring 11 has an inner peripheral surface 11a and an outer peripheral surface 11b. The outer peripheral surface 11b has a raceway surface of the inner ring 11. A shaft (not shown) is inserted into the inner ring 11.

The outer ring 12 has an annular shape. The outer ring 12 has an upper surface 12a, a lower surface 12b, an inner peripheral surface 12c, and an outer peripheral surface 12d. The upper surface 12a and the bottom surface 12b form end faces of the rolling bearing 10 in the central axial direction. The central axis direction is a direction along the axis of rotation of the rotating wheel of the rolling bearing (inner ring 11 in the rolling bearing 10). The inner peripheral surface 12c is connected to the upper surface 12a and the bottom surface 12b. The outer peripheral surface 12d is connected to the upper surface 12a and the bottom surface 12b. The outer ring 12 is arranged on the outside of the inner ring 11 so that the inner peripheral surface 12c faces the outer peripheral surface 11b. The outer ring 12 is attached to a housing (not shown).

A recess 12ca is formed on the inner peripheral surface 12c. The inner peripheral surface 12c is recessed on the outer peripheral surface 12d side in the recess 12ca. The bottom surface of the recess 12ca constitutes the raceway surface of the outer ring 12. From another point of view, the inner peripheral surface 12c has a collar 12cc formed on the upper surface 12a side of the recess 12ca and a collar 12cc formed on the bottom surface 12b side of the recess 12ca. The inner peripheral surface 12c between the 12cc and the brim 12cc constitutes the raceway surface of the outer ring 12.

The rolling element 13 has a cylindrical shape. The rolling element 13 has an upper surface 13a, a lower surface 13b, and an outer peripheral surface 13c. The outer peripheral surface 13c is connected to the upper surface 13a and the bottom surface 13b. The outer peripheral surface 13c constitutes the rolling surface of the rolling element 13. The rolling element 13 is arranged between the inner ring 11 and the outer ring 12. More specifically, the rolling element 13 is arranged in the recess 12ca so that the outer peripheral surface 13c is in contact with the bottom surface and the outer peripheral surface 11b of the recess 12ca and the upper surface 13a and the bottom surface 13b face the side surface of the recess 12ca. There is.

The cage 14 is a third electrode R. The cage 14 is a punching cage. The cage 14 is made of, for example, a conductive material. The cage 14 has an annular shape. The cage 14 has an inner peripheral surface 14a, an outer peripheral surface 14b, and a through hole 14c. The cage 14 is arranged between the inner ring 11 and the outer ring 12 so that the inner peripheral surface 14a faces the outer peripheral surface 11b and the outer peripheral surface 14b faces the inner peripheral surface 12c. The through hole 14c penetrates the cage 14 in the thickness direction (direction from the inner peripheral surface 14a to the outer peripheral surface 14b). A plurality of through holes 14c are formed at equal intervals along the circumferential direction. The circumferential direction is a direction along the circumference about the axis of rotation of the rotating wheel of the rolling bearing (inner ring 11 in the rolling bearing 10) when viewed from the central axis direction. The number of through holes 14c is equal to the number of rolling elements 13. A rolling element 13 is arranged in the through hole 14c. As a result, the rolling elements 13 are held in the cage 14 so that the intervals between the rolling elements 13 in the circumferential direction are equal.

A convex portion 14ba is formed on the outer peripheral surface 14b. The outer peripheral surface 14b projects on the convex portion 14ba on the side opposite to the inner peripheral surface 14a. The number of convex portions 14ba is preferably equal to the number of rolling elements 13. The convex portions 14ba are preferably arranged at equal intervals along the circumferential direction. A recess 14bb is formed on the outer peripheral surface 14b. The outer peripheral surface 14b is recessed on the inner peripheral surface 14a side in the recess 14bb. The number of recesses 14bb is preferably equal to the number of rolling elements 13. The concave portion 14bb is arranged between two adjacent convex portions 14bab. That is, the convex portions 14ba and the concave portions 14bb are alternately formed at equal intervals along the circumferential direction.

The first electrode 15 and the second electrode 16 are made of a conductive material. The first electrode 15 and the second electrode 16 are formed of, for example, copper (Cu) or a copper alloy. The first electrode 15 and the second electrode 16 are arranged at positions facing the cage 14. More specifically, the first electrode 15 and the second electrode 16 are arranged on the inner peripheral surface 12c located on the collar 12cc. The number of the first electrode 15 and the number of the second electrodes 16 are each an integral multiple of the number of the convex portions 14ba. In "The number of the first electrode 15 and the number of the second electrodes 16 are each an integral multiple of the number of the convex portions 14ba", the number of the first electrodes 15 and the number of the second electrodes 16 are each convex portions 14ba. Includes cases equal to the number of. The first electrode 15 and the second electrode 16 are alternately arranged at equal intervals along the circumferential direction. The plurality of first electrodes 15 may be integrally formed, and the plurality of second electrodes 16 may be integrally formed. However, the first electrode 15 is electrically separated from the second electrode 16.

With the relative rotation of the inner ring 11 with respect to the outer ring 12, the cage 14 revolves along the circumferential direction. The radial distance between the third electrode R (the cage 14 in the rolling bearing 10) and the first electrode 15 is defined as the first distance, and the radial distance between the third electrode R and the second electrode 16 is defined as the first distance. Let the distance be the second distance. Since the outer peripheral surface 14b is formed with the convex portion 14ba (and the concave portion 14bb), the first distance and the first distance and the first distance are accompanied by the relative rotation of the inner ring 11 with respect to the outer ring 12 (with the revolution of the cage 14). 2 Distance changes with time.

In the first electrode 15 and the second electrode 16, the phase of the time change of the first distance due to the relative rotation of the inner ring 11 with respect to the outer ring 12 and the time change of the second distance due to the relative rotation of the inner ring 11 with respect to the outer ring 12 Are arranged so that they are out of phase with each other.

In the rolling bearing 10, convex portions 14ba are arranged at equal intervals along the circumferential direction. Further, in the rolling bearing 10, the numbers of the first electrode 15 and the second electrode 16 are each an integral multiple of the number of the convex portions 14ba. Further, in the rolling bearing 10, the first electrode 15 and the second electrode 16 are alternately arranged at equal intervals along the circumferential direction. Therefore, in the rolling bearing 10, when the first electrode 15 faces the convex portion 14ba, the second electrode 16 does not face the convex portion 14ba, and the second electrode 16 faces the convex portion 14ba. At this time, the first electrode 15 does not face the convex portion 14ba, so that the phase of the time change of the first distance and the phase of the time change of the second distance are opposite phases.

FIG. 4 is an enlarged view of region IV of FIG. FIG. 5 is an enlarged view in the region V of FIG. As shown in FIGS. 4 and 5, the insulating film 17 is formed on the first electrode 15 and the second electrode 16. The insulating film 17 is formed of an insulating material. The insulating film 17 is made of, for example, polytetrafluoroethylene (the insulating film 17 is a polytetrafluoroethylene film). An insulating film 18 is formed between the first electrode 15 and the second electrode 16 and the outer ring 12 (more specifically, the collar 12 cc). The insulating film 18 is formed of an insulating material. As a result, the first electrode 15 and the second electrode 16 are electrically separated from the outer ring 12.

The thickness T of the insulating film 17 is preferably 180 μm or less. The thickness T is more preferably 100 μm or less. The thickness T is, for example, 12.5 μm or more. The distance between the insulating film 17 and the convex portion 14ba when the convex portion 14ba and the first electrode 15 (second electrode 16) face each other is defined as the distance DIS. The distance DIS is preferably 0.2 mm or less. The distance DIS may be 0. That is, the convex portion 14ba may be in contact with the insulating film 17 in a state where the convex portion 14ba and the first electrode 15 (second electrode 16) face each other.

The effect of the rolling bearing 10 will be described below.
FIG. 6A is a first explanatory view for explaining the effect of the rolling bearing 10. FIG. 6B is a second explanatory view for explaining the effect of the rolling bearing 10. FIG. 6C is a third explanatory view for explaining the effect of the rolling bearing 10. FIG. 6D is a fourth explanatory view for explaining the effect of the rolling bearing 10.

During operation of the rolling bearing 10, a lubricant L such as lubricating oil and grease is supplied to the inside of the rolling bearing 10. Therefore, as shown in FIG. 6A, the insulating film 17 and the convex portion 14ba on the first electrode 15 slide with each other via the lubricant L as the inner ring 11 rotates relative to the outer ring 12. .. As a result, a positive charge is induced in the first electrode 15 and a negative charge is induced in the second electrode 16.

When the relative rotation of the inner ring 11 with respect to the outer ring 12 progresses from the state shown in FIG. 6A, as shown in FIG. 6B, from the first electrode 15 based on the electromotive force caused by the electric charge induced in each electrode. A current flows through the second electrode 16.

When the relative rotation of the inner ring 11 with respect to the outer ring 12 progresses from the state shown in FIG. 6B, the insulating film 17 and the convex portion 14ba on the second electrode 16 pass through the lubricant L as shown in FIG. 6C. Sliding with each other. As a result, a negative charge is induced in the first electrode 15 and a positive charge is induced in the second electrode 16.

When the relative rotation of the inner ring 11 with respect to the outer ring 12 progresses from the state shown in FIG. 6C, as shown in FIG. 6D, from the second electrode 16 based on the electromotive force caused by the electric charge induced in each electrode. A current flows through the first electrode 15. When the rotation of the inner ring 11 relative to the outer ring 12 progresses from the state shown in FIG. 6D, the state returns to the state shown in FIG. 6A. As described above, in the rolling bearing 10, a pulsed current (voltage) is output from the first electrode 15 and the second electrode 16 as the inner ring 11 rotates relative to the outer ring 12. In the following, the voltage between the first electrode 15 and the second electrode 16 is referred to as an interelectrode voltage.

FIG. 7 is a schematic graph showing the relationship between the voltage between electrodes and the revolution speed of the cage 14. FIG. 8 is a schematic graph showing the relationship between the relative rotation speed of the inner ring 11 with respect to the outer ring 12 and the revolution speed of the cage 14. In FIG. 7, the horizontal axis is the revolution speed of the cage 14, and the vertical axis is the amplitude of the voltage between the electrodes. In FIG. 8, the horizontal axis is the rotation speed of the inner ring 11 relative to the outer ring 12, and the vertical axis is the revolution speed of the cage.

As shown in FIG. 7, as the revolution speed of the cage 14 increases, the voltage between the electrodes increases. Further, as shown in FIG. 8, as the rotation speed of the inner ring 11 with respect to the outer ring 12 increases, the rotation speed of the cage 14 increases. Specifically, there is a linear relationship between the rotation speed of the inner ring 11 with respect to the outer ring 12 and the revolution speed of the cage 14. The greater the relative rotational speed of the inner ring 11 with respect to the outer ring 12, the greater the voltage between the electrodes. Therefore, according to the rolling bearing 10, a sensor that detects the relative rotation speed of the inner ring 11 with respect to the outer ring 12 (or detects the revolution speed of the cage 14) is simply configured by monitoring the voltage between the electrodes. be able to.

When the amount of water mixed in the lubricant L changes, the dielectric constant of the lubricant L changes. As a result, when the convex portion 14ba slides on the insulating film 17, the amount of electric charge induced in the first electrode 15 and the second electrode 16 changes, and the voltage between the electrodes changes accordingly. Therefore, according to the rolling bearing 10, it is possible to easily configure a sensor that detects the amount of water mixed in the lubricant L by monitoring the voltage between the electrodes. Since the dielectric constant of the lubricant L changes due to the mixing of wear powder (iron powder) in the lubricant L and the deterioration of the lubricant L (heat deterioration, reduction of the base oil in the lubricant L), the voltage between the electrodes By monitoring the above, it is possible to detect the mixing of wear debris into the lubricant L and the deterioration of the lubricant L.

The electric power generated in the first electrode 15 and the second electrode 16 can be stored in a power storage unit such as a capacitor. Therefore, according to the rolling bearing 10, the power generation device can be easily configured.

The convex portions 14ba are arranged at equal intervals along the circumferential direction, the numbers of the first electrode 15 and the second electrode 16 are equal to the number of the convex portions 14ba, respectively, and the first electrode 15 and the second electrode 15 and the second electrode 16 are equal to each other. When the electrodes 16 are arranged at equal intervals along the circumferential direction, the time change of the first distance and the time change of the second distance are in opposite phases to each other. Therefore, in this case, it is possible to maximize the voltage between the electrodes and the current flowing between the first electrode 15 and the second electrode 16.

As the thickness T becomes smaller, the amount of electric charge induced in the first electrode 15 and the second electrode 16 when the convex portion 14ba slides with the insulating film 17 increases. Further, as the distance DIS becomes smaller, the amount of electric charge induced in the first electrode 15 and the second electrode 16 when the convex portion 14ba slides with the insulating film 17 increases. Therefore, by reducing the thickness T and the distance DIS, the voltage between the electrodes and the current flowing between the first electrode 15 and the second electrode 16 can be increased.

(Second Embodiment)
The configuration of the rolling bearing (hereinafter referred to as "rolling bearing 10A") according to the second embodiment will be described below. Here, the points different from the configuration of the rolling bearing 10 will be mainly described, and the overlapping description will not be repeated.

FIG. 9 is a top view of the rolling bearing 10A. FIG. 10 is a cross-sectional view taken along the line XX of FIG. FIG. 11 is a cross-sectional view taken along the line XI-XI of FIG. As shown in FIGS. 9 to 11, the rolling bearing 10A is a cylindrical roller bearing. The rolling bearing 10A has an inner ring 11, an outer ring 12, a rolling element 13, a cage 14, a first electrode 15, a second electrode 16, an insulating film 17, and an insulating film 18. In the first electrode 15 and the second electrode 16, the phase of the time change of the first distance due to the relative rotation of the inner ring 11 with respect to the outer ring 12 and the time change of the second distance due to the relative rotation of the inner ring 11 with respect to the outer ring 12 Are arranged so that they are out of phase with each other. Regarding these points, the configuration of the rolling bearing 10A is common to the configuration of the rolling bearing 10.

In the rolling bearing 10A, the rolling element 13 is the third electrode R instead of the cage 14. The rolling element 13 is formed of, for example, a conductive material. In the rolling bearing 10A, the first distance is the distance in the central axial direction between the rolling element 13 and the first electrode 15, and the second distance is the central axial direction between the rolling element 13 and the second electrode 16. It is the distance in. The cage 14 does not have a convex portion 14ba and a concave portion 14bb. It is preferable that the number of the first electrode 15 and the number of the second electrode 16 are each an integral multiple of the number of the rolling elements 13. The first electrode 15 and the second electrode 16 are arranged on the side surface of the recess 12ca. The cage 14 does not have to be made of a conductive material. In these respects, the configuration of the rolling bearing 10A is different from the configuration of the rolling bearing 10.

In the rolling bearing 10A, the first electrode 15 (second electrode 16) faces the rolling element 13 and does not face the rolling element 13 as the inner ring 11 rotates relative to the outer ring 12. And repeat. When the rolling element 13 and the first electrode 15 (second electrode 16) do not face each other, the first distance (second distance) can be regarded as infinite, so that even in the rolling bearing 10A. The first distance and the second distance change with time as the inner ring 11 rotates relative to the outer ring 12.

The effect of the rolling bearing 10A will be described below. Here, the points different from the effect of the rolling bearing 10 will be mainly described, and the overlapping description will not be repeated.

In the rolling bearing 10A as well, similarly to the rolling bearing 10, the first electrode 15 and the second electrode 16 have the phase of the time change of the first distance with respect to the relative rotation of the inner ring 11 with respect to the outer ring 12 and the phase of the inner ring 11 with respect to the outer ring 12. Since the phases of the time change of the second distance due to the relative rotation are arranged so as to be out of phase with each other, the inter-electrode voltage is generated with the relative rotation of the inner ring 11 with respect to the outer ring 12, and the first electrode A current flows between the 15 and the second electrode 16. Therefore, even with the rolling bearing 10A, a sensor or a power generation device capable of detecting the state of the rolling bearing can be easily configured.

(Third Embodiment)
The configuration of the rolling bearing (hereinafter referred to as "rolling bearing 20") according to the third embodiment will be described below.

FIG. 12 is a top view of the rolling bearing 20. FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. FIG. 14 is a cross-sectional view taken along the line XIV-XIV of FIG. As shown in FIGS. 12 to 14, the rolling bearing 20 is a conical roller bearing. The rolling bearing 20 includes an inner ring 21, an outer ring 22, a rolling element 23, a cage 24, a first electrode 25, a second electrode 26, an insulating film 27 and an insulating film 28 (specifically, FIG. 15 and FIG. 15 and (See FIG. 16).

The inner ring 21 has an annular shape. The inner ring 21 has an upper surface 21a, a lower surface 21b, an inner peripheral surface 21c, and an outer peripheral surface 21d. The upper surface 21a and the bottom surface 21b form end faces of the rolling bearing 20 in the central axial direction. The outer peripheral surface 21d has a raceway surface of the inner ring 21. A collar 21e is formed on the upper surface 21a side of the outer peripheral surface 21d.

The outer ring 22 has an annular shape. The outer ring 22 has an inner peripheral surface 22a and an outer peripheral surface 22b. The inner peripheral surface 22a has a raceway surface of the outer ring 22. The outer ring 22 is arranged on the outside of the inner ring 21 so that the inner peripheral surface 22a faces the outer peripheral surface 21d. The outer ring 22 is attached to a housing (not shown).

The rolling element 23 has an upper surface 23a, a lower surface 23b, and a side surface 23c. The diameter of the upper surface 23a is larger than the diameter of the bottom surface 23b, and the side surface 23c is continuous with the upper surface 23a and the bottom surface 23b. The side surface 23c constitutes the rolling surface of the rolling element 23. The rolling element 23 has a truncated cone shape. The rolling element 23 is arranged between the inner ring 21 and the outer ring 22 so that the side surface 23c is in contact with the outer peripheral surface 21d and the inner peripheral surface 22a. The rolling element 23 is arranged so that the bottom surface 23b faces the side surface of the collar 21e.

The cage 24 is a punching cage. The cage 24 has a third electrode R. The cage 24 has an annular shape. The cage 24 has an inner peripheral surface 24a, an outer peripheral surface 24b, and a through hole 24c. The cage 24 is arranged between the inner ring 21 and the outer ring 22 so that the inner peripheral surface 24a faces the outer peripheral surface 21d and the outer peripheral surface 24b faces the inner peripheral surface 22a. The through hole 24c penetrates along the thickness direction of the cage 24 (the direction from the inner peripheral surface 24a to the outer peripheral surface 24b). The number of through holes 24c is equal to the number of rolling elements 23. A rolling element 23 is arranged in the through hole 24c. As a result, the rolling elements 23 are held in the cage 24 so that the intervals between the rolling elements 23 in the circumferential direction are equal. The cage 24 is made of, for example, a conductive material.

A convex portion 24aa is formed on the inner peripheral surface 24a. The inner peripheral surface 24a projects on the convex portion 24aa on the side opposite to the outer peripheral surface 24b. The number of convex portions 24aa is preferably equal to the number of rolling elements 13. The convex portions 24aa are preferably arranged at equal intervals along the circumferential direction. A recess 24ab is formed on the inner peripheral surface 24a. The inner peripheral surface 24a is recessed on the outer peripheral surface 24b side in the recess 24ab. The number of recesses 24ab is preferably equal to the number of rolling elements 23. The recess 24ab is arranged between two adjacent convex portions 24aa. That is, the convex portions 24aa and the concave portions 24ab are alternately formed at equal intervals along the circumferential direction.

The first electrode 25 and the second electrode 26 are made of a conductive material. The first electrode 25 and the second electrode 26 are formed of, for example, copper or a copper alloy. The first electrode 25 and the second electrode 26 are arranged at positions facing the cage 24. More specifically, the first electrode 25 and the second electrode 26 are arranged on the outer peripheral surface 21d located on the collar 21e.

The number of the first electrode 25 and the number of the second electrodes 26 are each an integral multiple of the number of the convex portions 24aa. In "The number of the first electrode 25 and the number of the second electrodes 26 are each an integral multiple of the number of the convex portions 24aa", the number of the first electrodes 25 and the number of the second electrodes 26 are each the convex portions 24aa. Includes cases equal to the number of. The first electrode 25 and the second electrode 26 are alternately arranged along the circumferential direction. The plurality of first electrodes 25 may be integrally formed, and the plurality of second electrodes 26 may be integrally formed. However, the first electrode 25 is electrically separated from the second electrode 26.

With the relative rotation of the inner ring 21 with respect to the outer ring 22, the cage 24 revolves along the circumferential direction. The radial distance between the third electrode R (the cage 24 in the rolling bearing 20) and the first electrode 25 is defined as the first distance, and the radial distance between the third electrode R and the second electrode 26 is defined as the first distance. Let the distance be the second distance. Since the inner peripheral surface 24a is formed with the convex portion 24aa (and the concave portion 24ab), the first distance and the first distance and the relative rotation of the inner ring 21 with respect to the outer ring 22 (with the revolution of the cage 24) The second distance changes with time.

In the first electrode 25 and the second electrode 26, the phase of the time change of the first distance due to the relative rotation of the inner ring 21 with respect to the outer ring 22 and the time change of the second distance due to the relative rotation of the inner ring 21 with respect to the outer ring 22. Are arranged so that they are out of phase with each other.

In the rolling bearing 20, convex portions 24aa are arranged at equal intervals along the circumferential direction. Further, in the rolling bearing 20, the number of the first electrode 25 and the number of the second electrode 26 are equal to the number of the convex portions 24aa, respectively. Further, in the rolling bearing 20, the first electrode 25 and the second electrode 26 are arranged at equal intervals along the circumferential direction. Therefore, in the rolling bearing 20, when the first electrode 25 faces the convex portion 24aa, the second electrode 26 does not face the convex portion 24aa, and the second electrode 26 faces the convex portion 24aa. At this time, the first electrode 25 does not face the convex portion 24aa, so that the phase of the time change of the first distance and the phase of the time change of the second distance are opposite phases.

FIG. 15 is an enlarged view in the region XV of FIG. FIG. 16 is an enlarged view of the region XVI of FIG. As shown in FIGS. 15 and 16, the insulating film 27 is formed on the first electrode 25 and the second electrode 26. The insulating film 27 is formed of an insulating material. The insulating film 27 is made of, for example, polytetrafluoroethylene (the insulating film 27 is a polytetrafluoroethylene film). The thickness T of the insulating film 27 is preferably 180 μm or less. The thickness T is more preferably 100 μm or less. The thickness T is, for example, 12.5 μm or more. The insulating film 28 is formed between the first electrode 25 and the second electrode 26 and the inner ring 21 (more specifically, the collar 21e). The insulating film 28 is formed of an insulating material. As a result, the first electrode 25 and the second electrode 26 are electrically separated from the inner ring 21.

The effect of the rolling bearing 20 will be described below.
In the rolling bearing 20, as in the rolling bearing 10, the first electrode 25 and the second electrode 26 have the phase of the time change of the first distance with respect to the relative rotation of the inner ring 21 with respect to the outer ring 22 and the inner ring 11 with respect to the outer ring 12. Since the phases of the time change of the second distance due to the relative rotation of the two are arranged so as to be out of phase with each other, the inter-electrode voltage is generated with the relative rotation of the inner ring 21 with respect to the outer ring 22, and the first A current flows between the electrode 25 and the second electrode 26. Therefore, even with the rolling bearing 20, it is possible to easily configure a sensor or a power generation device capable of detecting the state of the rolling bearing.

(Fourth Embodiment)
The configuration of the rolling bearing (hereinafter referred to as "rolling bearing 20A") according to the fourth embodiment will be described below. Here, the points different from the configuration of the rolling bearing 20 will be mainly described, and the overlapping description will not be repeated.

FIG. 17 is a bottom view of the rolling bearing 20A. FIG. 18 is a cross-sectional view taken along the line XVIII-XVIII of FIG. FIG. 19 is a cross-sectional view taken along the line XIX-XIX of FIG. As shown in FIGS. 17 to 19, the rolling bearing 20A is a conical roller bearing. The rolling bearing 20A has an inner ring 21, an outer ring 22, a rolling element 23, a cage 24, a first electrode 25, a second electrode 26, an insulating film 27, and an insulating film 28. In the first electrode 25 and the second electrode 26, the phase of the time change of the first distance due to the relative rotation of the inner ring 21 with respect to the outer ring 22 and the time change of the second distance due to the relative rotation of the inner ring 21 with respect to the outer ring 22. Are arranged so that they are out of phase with each other. Regarding these points, the configuration of the rolling bearing 20A is common to the configuration of the rolling bearing 20.

In the rolling bearing 20A, the rolling element 23 is the third electrode R instead of the cage 24. The first distance is the distance in the central axis direction between the rolling element 23 and the first electrode 25. The second distance is the distance in the central axis direction between the rolling element 13 and the second electrode 16. The rolling element 23 is formed of, for example, a conductive material. The cage 24 does not have to be made of a conductive material. The cage 24 does not have a convex portion 24aa and a concave portion 24ab. It is preferable that the number of the first electrode 25 and the number of the second electrode 26 are each an integral multiple of the number of the rolling elements 23. The first electrode 25 and the second electrode 26 are arranged on the side surface of the collar 21e. In these respects, the configuration of the rolling bearing 20A is different from the configuration of the rolling bearing 20.

In the rolling bearing 20A, the first electrode 25 (second electrode 26) faces the rolling element 23 and does not face the rolling element 23 as the inner ring 21 rotates relative to the outer ring 22. And repeat. When the rolling element 23 and the first electrode 25 (second electrode 26) do not face each other, the first distance (second distance) can be regarded as infinite, so that even in the rolling bearing 20A. The first distance and the second distance change with time as the inner ring 21 rotates relative to the outer ring 22.

The effect of the rolling bearing 20A will be described below. Here, the points different from the effect of the rolling bearing 20 will be mainly described, and the overlapping description will not be repeated.

In the rolling bearing 20A, similarly to the rolling bearing 20, the first electrode 25 and the second electrode 26 have the phase of the time change of the first distance with respect to the relative rotation of the inner ring 21 with respect to the outer ring 22 and the phase of the inner ring 21 with respect to the outer ring 22. Since the phases of the time change of the second distance due to the relative rotation are arranged so as to be out of phase with each other, an interelectrode voltage is generated with the relative rotation of the inner ring 21 with respect to the outer ring 22, and the first electrode A current flows between the 25 and the second electrode 26. Therefore, even with the rolling bearing 20A, it is possible to easily configure a sensor or a power generation device capable of detecting the state of the rolling bearing.

(Fifth Embodiment)
The configuration of the rolling bearing (hereinafter referred to as “rolling bearing 30”) according to the fifth embodiment will be described below.

FIG. 20 is a top view of the rolling bearing 30. FIG. 21 is a cross-sectional view taken along the line XXI-XXI of FIG. FIG. 22 is a cross-sectional view taken along the line XXII-XXII of FIG. As shown in FIGS. 20 to 22, the rolling bearing 30 is a ball bearing. The rolling bearing 30 has an inner ring 31, an outer ring 32, a rolling element 33, a cage 34, a first electrode 35, a second electrode 36, an insulating film 37 and an insulating film 39, and a sealing member 38. are doing.

The inner ring 31 has an annular shape. The inner ring 31 has an inner peripheral surface 31a and an outer peripheral surface 31b. The outer peripheral surface 31b has a raceway surface of the inner ring 31. A shaft is inserted into the inner ring 31.

The outer ring 32 has an annular shape. The outer ring 32 has an inner peripheral surface 32a and an outer peripheral surface 32b. The inner peripheral surface 32a has a raceway surface of the outer ring 32. The outer ring 32 is arranged outside the inner ring 31 so that the inner peripheral surface 32a faces the outer peripheral surface 31b.

The rolling element 33 has a spherical shape. The rolling element 33 has a surface 33a. The rolling element 33 is arranged between the inner ring 31 and the outer ring 32 so that the surface 33a is in contact with the outer peripheral surface 31b and the inner peripheral surface 32a.

The cage 34 is a punched cage in which a portion for holding the rolling element 33 is formed by punching a steel plate. The cage 34 has a holding portion 34a and a connecting portion 34b. The holding portions 34a and the connecting portions 34b are alternately arranged at equal intervals along the circumferential direction. The holding portion 34a is a portion that holds the rolling element 33. The connecting portion 34b is a portion connecting two holding portions 34a adjacent to each other in the circumferential direction. The cage 34 has a convex portion 34c protruding along the central axis direction in a portion holding the rolling element 33. In the examples shown in FIGS. 20 to 22, the holding portion 34a has a curved surface along the surface 33a of the rolling element 33, and the curved surface portion itself has a convex portion 34c. A portion that protrudes along the central axis direction may be further formed near the apex of the curved surface portion that holds the rolling element 33 by press working or the like, and the protruding portion may be a convex portion 34c. The above press working may be performed at the same time as the punching work for forming the holding portion 34a. That is, in the case where "the cage 34 has a convex portion 34c protruding along the central axis direction in the portion holding the rolling element 33", the holding portion 34a itself is the convex portion 34c. And the case where the convex portion 34c is formed in the holding portion 34a are included. The number of convex portions 34c is equal to the number of rolling elements 33. The cage 34 is a third electrode R. The cage 34 has an annular shape. The rolling elements 33 are held in the cage 34 so that the rolling elements 33 are evenly spaced in the circumferential direction. The cage 34 is made of a conductive material.

The seal member 38 is attached to the outer ring 32 so as to demarcate the bearing space between the inner ring 31 and the outer ring 32. The seal member 38 may be a seal plate or a shield plate. The seal member 38 has a front surface 38a and a back surface 38b. The surface 38a is a surface facing the bearing space side. From another point of view, the surface 38a is the surface facing the cage 34. The back surface 38b is the opposite surface of the front surface 38a.

The first electrode 35 and the second electrode 36 are arranged on the seal member 38. More specifically, the first electrode 35 and the second electrode 36 are arranged on the surface 38a. It is preferable that the number of the first electrode 35 and the number of the second electrode 36 are each an integral multiple of the number of the rolling elements 33. In "The number of the first electrode 35 and the number of the second electrode 36 are each an integral multiple of the number of the rolling elements 33", the number of the first electrode 35 and the number of the second electrodes 36 are each of the rolling elements. Includes cases equal to a number.

The first electrode 35 and the second electrode 36 are alternately arranged along the circumferential direction. The plurality of first electrodes 35 may be integrally formed, and the plurality of second electrodes 36 may be integrally formed. However, the first electrode 35 is electrically separated from the second electrode 36.

With the relative rotation of the inner ring 31 with respect to the outer ring 32, the cage 34 revolves along the circumferential direction. The distance in the central axis direction between the third electrode R (in the rolling bearing 30, the cage 34) and the first electrode 35 is defined as the first distance, and the central axis between the third electrode R and the second electrode 36. The distance in the direction is defined as the second distance. Since the cage 34 is a punched cage (having a convex portion 34c), the first electrode is associated with the relative rotation of the inner ring 31 with respect to the outer ring 32 (that is, with the revolution of the cage 34). The state of the 35 (second electrode 36) facing the convex portion 34c and the state of not facing the convex portion 34c are repeated, and the first distance and the second distance change with time.

The first electrode 35 and the second electrode 36 have a phase of time change of the first distance due to the relative rotation of the inner ring 31 with respect to the outer ring 32 and a time change of the second distance due to the relative rotation of the inner ring 31 with respect to the outer ring 32. Are arranged so that they are out of phase with each other.

In the rolling bearing 30, rolling elements 33 are arranged at equal intervals along the circumferential direction. Further, in the rolling bearing 30, the cage 34 is a punched cage. Further, in the rolling bearing 30, the numbers of the first electrode 25 and the second electrode 26 are each an integral multiple of the number of the rolling elements 33, and the first electrode 35 and the second electrode 36 are along the circumferential direction. They are evenly spaced. Therefore, in the rolling bearing 30, when the first electrode 35 faces the rolling element 33, the second electrode 36 does not face the rolling element 33, so that the first distance increases while the second distance increases. Becomes smaller. Further, when the second electrode 36 faces the rolling element 33, the first electrode 35 does not face the rolling element 33, so that the second distance increases while the first distance decreases. As described above, in the rolling bearing 30, the phase of the time change of the first distance and the phase of the time change of the second distance are opposite phases.

The insulating film 37 is formed on the first electrode 35 and the second electrode 36. The insulating film 37 is formed of an insulating material. The insulating film 37 is made of, for example, polytetrafluoroethylene (the insulating film 37 is a polytetrafluoroethylene film). The thickness T of the insulating film 37 is preferably 180 μm or less. The thickness T is more preferably 100 μm or less. The thickness T is, for example, 12.5 μm or more. An insulating film 39 is formed between the first electrode 35 and the second electrode 36 and the sealing member 38 (more specifically, the surface 38a). The insulating film 39 is formed of an insulating material. As a result, the first electrode 35 and the second electrode 36 and the seal member 38 are electrically separated from each other.

The effect of the rolling bearing 30 will be described below.
In the rolling bearing 30, as in the rolling bearing 10, the first electrode 35 and the second electrode 36 have the phase of the time change of the first distance with respect to the relative rotation of the inner ring 31 with respect to the outer ring 32 and the inner ring 31 with respect to the outer ring 32. Since the phases of the time change of the second distance due to the relative rotation of the two are arranged so as to be out of phase with each other, the inter-electrode voltage is generated with the relative rotation of the inner ring 31 with respect to the outer ring 32, and the first A current flows between the electrode 35 and the second electrode 36. Therefore, even with the rolling bearing 30, it is possible to easily configure a sensor or a power generation device capable of detecting the state of the rolling bearing.

(Sixth Embodiment)
The configuration of the rolling bearing (hereinafter referred to as "rolling bearing 40") according to the sixth embodiment will be described below.

FIG. 23 is a cross-sectional view of the rolling bearing 40. FIG. 24 is a cross-sectional view of the rolling bearing 40 in a state where the inner member 41 is rotated relative to the outer member 42. As shown in FIGS. 23 and 24, the rolling bearing 40 is a hub bearing. The rolling bearing 40 includes an inner member 41, an outer member 42 (outer ring), a rolling element 43a and a rolling element 43b, a cage 44a and a cage 44b, a first electrode 45, a second electrode 46, and the like. It has an insulating film 47.

The inner member 41 has a hub ring 41a and an inner ring 41b. The outer peripheral surface of the hub ring 41a has a raceway surface 41aa. The hub ring 41a has a small diameter portion 41ab. The outer peripheral surface of the hub ring 41a is recessed on the inner peripheral surface side of the hub ring 41a in the small diameter portion 41ab. The inner ring 41b is fixed to the hub ring 41a by inserting the small diameter portion 41ab. The outer peripheral surface of the inner ring 41b has a raceway surface 41ba.

The outer member 42 has an inner peripheral surface 42a. The outer member 42 is arranged outside the inner member 41 so that the inner peripheral surface 42a faces the raceway surface 41aa and the raceway surface 41ba. The inner peripheral surface 42a has a raceway surface of the outer member 42.

The rolling element 43a is arranged between the raceway surface 41aa and the inner peripheral surface 42a, and the rolling element 43b is arranged between the raceway surface 41ba and the inner peripheral surface 42a. The outer member 42 has a protruding portion 42b on the inner peripheral surface 42a. The projecting portion 42b projects from the inner peripheral surface 42a toward the inner member 41 side along the radial direction between the rolling element 43a and the rolling element 43b.

The cage 44a is the third electrode R. The cage 44a has an annular shape. The cage 44a is made of a conductive material. The rolling elements 43a are held in the cage 44a so that the rolling elements 43a are evenly spaced in the circumferential direction. The cage 44a has a convex portion 44aa. A plurality of convex portions 44aa are formed at equal intervals along the circumferential direction. The convex portion 44aa is formed so as to project toward the protruding portion 42b on the surface of the cage 44a facing the protruding portion 42b. The cage 44b holds the rolling elements 43b so that the rolling elements 43b are evenly spaced in the circumferential direction.

The first electrode 45 and the second electrode 46 are made of a conductive material. The first electrode 45 and the second electrode 46 are formed of, for example, copper or a copper alloy. The first electrode 45 and the second electrode 46 are arranged at positions facing the cage 44a. More specifically, the first electrode 45 and the second electrode 46 are arranged on the protrusion 42b. The number of the first electrode 45 and the number of the second electrodes 46 are each an integral multiple of the number of the convex portions 44aa. The first electrode 45 and the second electrode 46 are alternately arranged along the circumferential direction. The plurality of first electrodes 45 may be integrally formed, and the plurality of second electrodes 46 may be integrally formed. However, the first electrode 45 is electrically separated from the second electrode 46. Although not shown, the first electrode 45 and the second electrode 46 are electrically separated from the protrusion 42b by an insulating film formed between the first electrode 45 and the second electrode 46.

With the relative rotation of the inner member 41 with respect to the outer member 42, the cage 44a revolves along the circumferential direction. The distance in the central axis direction between the third electrode R (in the rolling bearing 40, the cage 44a) and the first electrode 45 is defined as the first distance, and the central axis between the third electrode R and the second electrode 16. The distance in the direction is defined as the second distance. Since the convex portion 44aa is formed on the surface of the cage 44a facing the protruding portion 42b, the convex portion 44aa is formed with the relative rotation of the inner member 41 with respect to the outer member 42 (with the revolution of the cage 44a). , The first distance and the second distance change with time.

In the first electrode 45 and the second electrode 46, the phase of the time change of the first distance accompanying the relative rotation of the inner member 41 with respect to the outer member 42 and the relative rotation of the inner member 41 with respect to the outer member 42. It is arranged so as to be out of phase with the phase of the time change of the second distance accompanying the above.

In the rolling bearing 40, the convex portions 44aa are arranged at equal intervals along the circumferential direction. Further, in the rolling bearing 40, the numbers of the first electrode 45 and the second electrode 46 are equal to the number of the convex portions 44aa, respectively, and the first electrode 45 and the second electrode 46 are evenly spaced along the circumferential direction. It is arranged in. Therefore, in the rolling bearing 40, when the first electrode 45 faces the convex portion 44aa, the second electrode 46 does not face the convex portion 44aa, and the second electrode 46 faces the convex portion 44aa. At this time, the first electrode 45 does not face the convex portion 44aa, so that the phase of the time change of the first distance and the phase of the time change of the second distance are opposite phases.

The insulating film 47 is formed on the first electrode 45 and the second electrode 46. The insulating film 47 is formed of an insulating material. The insulating film 47 is made of, for example, polytetrafluoroethylene (the insulating film 47 is a polytetrafluoroethylene film).

The effect of the rolling bearing 40 will be described below.
In the rolling bearing 40 as well, similarly to the rolling bearing 10, the first electrode 45 and the second electrode 46 are the phase and the outside of the time change of the first distance due to the relative rotation of the inner member 41 with respect to the outer member 42. Since the phases of the time change of the second distance due to the relative rotation of the inner member 41 with respect to the square member 42 are arranged so as to be offset from each other, the relative rotation of the inner member 41 with respect to the outer member 42 Along with this, an inter-electrode voltage is generated, and a current flows between the first electrode 45 and the second electrode 46. Therefore, even with the rolling bearing 40, it is possible to easily configure a sensor or a power generation device capable of detecting the state of the rolling bearing.

(Application to other rolling bearings)
The rolling bearings for railway vehicles using double-row cylindrical roller bearings and the rolling bearings for railway vehicles using double-row conical roller bearings have also been described in the first to sixth embodiments. By applying the first electrode, the second electrode, the insulating film, and the third electrode, it is possible to form a rolling bearing that operates in the same manner as the rolling bearings 10 to 40.

(7th Embodiment)
The configuration of the power generation device (hereinafter referred to as “power generation device 100”) according to the seventh embodiment will be described below.

FIG. 25 is a block diagram of the power generation device 100. As shown in FIG. 25, the power generation device 100 includes a rolling bearing 10 and a power storage unit 50. In the power generation device 100, instead of the rolling bearing 10, a rolling bearing 10A, a rolling bearing 20, a rolling bearing 20A, a rolling bearing 30, or a rolling bearing 40 may be used. The power storage unit 50 is composed of, for example, a capacitor. The power storage unit 50 is electrically connected to the first electrode 15 and the second electrode 16. As a result, the electrodes generated in the first electrode 15 and the second electrode 16 due to the relative rotation of the inner ring 11 with respect to the outer ring 12 are accumulated in the power storage unit 50.

The configuration of the rolling bearing with a sensor (hereinafter referred to as “rolling bearing 200 with a sensor”) according to the eighth embodiment will be described below.

FIG. 26 is a block diagram of the rolling bearing 200 with a sensor. As shown in FIG. 26, the rolling bearing 200 with a sensor has a rolling bearing 10 and a detection unit 60. In the rolling bearing 200 with a sensor, instead of the rolling bearing 10, a rolling bearing 10A, a rolling bearing 20, a rolling bearing 20A, a rolling bearing 30, or a rolling bearing 40 can be used.

The detection unit 60 is electrically connected to the first electrode 15 and the second electrode 16. The detection unit 60 is configured to be able to detect the revolution speed of the cage 14 based on the voltage between the electrodes. The detection unit 60 may be configured to be able to estimate the relative rotation speed of the inner ring 11 with respect to the outer ring 12 based on the revolution speed of the cage 14. The relative rotation speed of the inner ring 11 with respect to the outer ring 12 is estimated by multiplying the revolution speed of the cage 14 detected based on the voltage between the electrodes by a predetermined coefficient. The detection unit 60 is in a state of the lubricant L supplied to the inside of the rolling bearing 10 based on the voltage between the electrodes (for example, the amount of water mixed in the lubricant L, the amount of wear powder mixed in the lubricant L). , The degree of deterioration of the lubricant L, etc.) may be detected. The detection unit 60 can be configured by an appropriate electronic circuit. The detection unit 60 is composed of, for example, a microcontroller.

Although the embodiments of the present invention have been described above, the above-described embodiments can be variously modified. Moreover, the scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by the scope of claims and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The above embodiment is particularly advantageously applied to rolling bearings such as cylindrical roller bearings, conical roller bearings, ball bearings, hub bearings, and rolling bearings for railway vehicles.

10 Rolling bearing 11 Inner ring, 11a Inner peripheral surface, 11b Outer surface, 12 Outer ring, 12a Upper surface, 12b Bottom surface, 12c Inner peripheral surface, 12ca recess, 12cc, 12cc collar, 13 Rolling element 13a Upper surface, 13b Bottom surface, 13c side surface, 14 Cage, 14a inner peripheral surface, 14b outer peripheral surface, 14ba convex part, 14bb concave part, 14c through hole, 15 first electrode, 16 second electrode, 17 insulating film, 18 insulating film, 10A rolling bearing, 20 rolling bearing, 21 Inner ring, 21a upper surface, 21b bottom surface, 21c inner peripheral surface 21d outer peripheral surface, 21e collar, 22 outer ring, 22a inner peripheral surface, 22b outer peripheral surface, 23 rolling elements, 23a upper surface, 23b bottom surface, 23c side surface, 24 cage, 24a inner surface. Peripheral surface, 24aa convex part, 24ab concave part, 24b outer peripheral surface, 24c through hole, 25 1st electrode, 26 2nd electrode, 27 insulating film, 28 insulating film, 20A rolling bearing, 30 rolling bearing, 31 inner ring, 31a inner circumference Surface, 31b outer peripheral surface, 32 outer ring, 32a inner peripheral surface, 32b outer peripheral surface, 33 rolling element, 33a surface, 34 cage, 34a holding part, 34b connecting part, 34c convex part, 35 first electrode, 36 second electrode , 37 Insulation film, 38 Seal member, 38a front surface, 38b back surface, 39 insulation film, 40 rolling bearing 41 inner member, 41a hub ring, 41aa track surface, 41b inner ring, 41ba track surface, 42 outer member, 42a inner circumference Surface, 42b projecting part, 43a, 43b rolling element, 44a cage, 44aa convex part, 44b cage, 45 1st electrode, 46 2nd electrode, 47 insulating film, 50 power storage unit, 60 detector, 100 power generator, 200 Rolling bearing with sensor, L lubricant, R 3rd electrode, T thickness, DIS distance.

Claims (12)

Inner ring and
An outer ring arranged outside the inner ring and
A rolling element arranged between the inner ring and the outer ring,
A cage that is arranged between the inner ring and the outer ring and holds the rolling element,
The first and second electrodes formed of a conductive material,
The first electrode and the insulating film formed on the surface of the second electrode are provided.
One of the rolling element and the cage is a third electrode.
The first distance, which is the distance between the first electrode and the third electrode, and the second distance, which is the distance between the second electrode and the third electrode, are relative to the rotation of the inner ring with respect to the outer ring. Changes with
A rolling bearing in which the time change of the first distance due to the relative rotation of the inner ring with respect to the outer ring is out of phase with the time change of the second distance due to the relative rotation of the inner ring with respect to the outer ring. The rolling element is a ball and
The cage is the third electrode.
The rolling bearing according to claim 1, wherein the cage has a convex portion protruding along the central axis direction at a portion holding the rolling element. The rolling elements are arranged at equal intervals along the circumferential direction.
The number of the first electrode and the number of the second electrode are each an integral multiple of the number of the rolling elements.
The rolling bearing according to claim 1 or 2, wherein the first electrode and the second electrode are alternately arranged at equal intervals along the circumferential direction. The cage is the third electrode.
The rolling bearing according to claim 1, wherein a convex portion projecting toward the first electrode is formed on the surface of the cage facing the first electrode. The convex portions are arranged at equal intervals along the circumferential direction.
The number of the first electrode and the number of the second electrode are each an integral multiple of the number of the convex portions.
The rolling bearing according to claim 4, wherein the first electrode and the second electrode are alternately arranged at equal intervals along the circumferential direction. Further provided with a sealing member that defines a bearing space between the inner ring and the outer ring.
The rolling bearing according to any one of claims 1 to 5, wherein the first electrode and the second electrode are arranged on a surface of the sealing member on the bearing space side. The rolling bearing according to any one of claims 1 to 6, wherein the insulating film is a polytetrafluoroethylene film. The rolling bearing according to any one of claims 1 to 7, wherein the thickness of the insulating film is 100 μm or less. The rolling bearing according to any one of claims 1 to 8.
A rolling bearing with a sensor, comprising a detection unit that detects the revolution speed of the cage based on the voltage between the first electrode and the second electrode. The rolling bearing with a sensor according to claim 9, wherein the detection unit is configured to be able to estimate the relative rotation speed of the inner ring with respect to the outer ring based on the revolution speed of the cage. The rolling bearing according to any one of claims 1 to 8.
A rolling bearing with a sensor, comprising a detection unit that detects the state of the lubricant supplied to the inside of the rolling bearing based on the voltage between the first electrode and the second electrode. The rolling bearing with a sensor according to claim 11, wherein the state of the lubricant detected by the detection unit is the water content in the lubricant.

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