Search

EP-4484778-B1 - BEARING DEVICE

EP4484778B1EP 4484778 B1EP4484778 B1EP 4484778B1EP-4484778-B1

Inventors

  • KOIKE, TAKASHI
  • FUKUSHIMA, YASUYUKI
  • MATSUBAYASHI, Kohei
  • MAKINO, TOMOAKI

Dates

Publication Date
20260506
Application Date
20230315

Claims (5)

  1. A bearing device (1) comprising: a bearing (2) including an outer ring (3), an inner ring (4), and a rolling element (8); a magnetic ring (7) fixed to one of the outer ring (3) or the inner ring (4); a stator (5) disposed to face the magnetic ring (7) in a radial direction of the bearing (2) and fixed to the other of the outer ring (3) or the inner ring (4); and a circuit board (13), wherein the magnetic ring (7) and the stator (5) constitute a generator (G) that generates AC power, the circuit board (13) includes at least one sensor (15,16) that detects a state of the bearing (2), a wireless communication circuit (18) that wirelessly transmits an output from the at least one sensor to outside, and a power supply circuit (17) that converts AC power generated by the generator (G) into DC power usable in the at least one sensor and the wireless communication circuit (18), and the magnetic ring (7), the stator (5), and the circuit board (13) are disposed in an annular space so as not to overlap with each other in an axial direction of the bearing (2), the annular space being formed by an end portion of the outer ring (3) and an end portion of the inner ring (4).
  2. The bearing device (1) according to claim 1, wherein the circuit board (13) has an arc shape, and the at least one sensor, the wireless communication circuit (18), and the power supply circuit (17) are disposed on a circumference of the circuit board (13) so as not to overlap with each other in an axial direction.
  3. The bearing device (1) according to claim 1 or 2, wherein the bearing is a standard bearing (2) that has main dimensions defined under specific standards.
  4. The bearing device (1) according to claim 3, wherein the specific standards are ISO standards or JIS standards.
  5. The bearing device (1) according to claim 4, wherein the standard bearing (2) is a radial bearing, and main dimensions of the radial bearing are dimensions defined in ISO 15 or JIS B 1512-1.

Description

TECHNICAL FIELD The present disclosure relates to a bearing device. BACKGROUND ART There is known a bearing device formed of a combination of a bearing and a generator and used as a power supply for a sensor, wireless communication, and the like. JP 2017 072170 A (Japanese Patent Laying-Open No. 2017-72170) (PTL 1) discloses a bearing device equipped with a wireless sensor and configured to wirelessly transmit information from a sensor. The bearing device disclosed in PTL 1 has a structure in which a multipole ring magnet is fixed to one end of a cage holding a rolling element, and a coil is disposed on a seal side facing the multipole ring magnet. In the bearing device disclosed in PTL 1, electric power is generated by relative rotation of the multipole ring magnet and the coil that are disposed in the axial direction. US 2012 / 169166 A1 (PTL 2) discloses a bearing which has a first bearing ring, a second bearing ring and a claw pole generator-type power generation unit. The bearing has a substantially space-neutral power generation unit, which has a high filling factor for the induction coil. Every claw ring is connected to a section of the body of the first bearing ring in a magnetically conducting fashion and the magnetic circuit is substantially closed via the section of the body of the first bearing ring. CITATION LIST PATENT LITERATURE PTL 1: JP 2017 072170 A (Japanese Patent Laying-Open No. 2017-72170)PTL 2: US 2012 / 169166 A1 SUMMARY OF INVENTION TECHNICAL PROBLEM In this case, due to its use, the cage significantly rattles in the axial direction of the bearing. For this reason, in the bearing device in PTL 1, the gap between the multipole ring magnet and the coil in the axial direction tends to vary due to such rattling of the cage caused by its use. In the bearing device in PTL 1, it is conceivable that, when the gap becomes larger, the amount of power generation decreases, which exerts an influence upon the driving of electronic components such as a sensor. In the bearing device in PTL 1, it is conceivable that, when the gap becomes smaller, the multipole ring magnet comes into contact with electronic components such as a sensor. The present disclosure has been made to solve the above-described problems, an object thereof is to provide a bearing device that is reduced in dimensions and still capable of functioning normally. SOLUTION TO PROBLEM The above-described problems are solved by a bearing device according to independent claim 1. Further developments are subject matter of the dependent claims. A bearing device of the present disclosure includes: a standard bearing as a bearing that includes an outer ring, an inner ring, and a rolling element, the bearing having main dimensions defined under specific standards. The bearing device includes: a magnetic ring fixed to one of the outer ring or the inner ring; a stator disposed to face the magnetic ring in a radial direction of the standard bearing and fixed to the other of the outer ring or the inner ring; and a circuit board. The magnetic ring and the stator constitute a generator that generates alternating-current (AC) power. The circuit board includes: at least one sensor that detects a state of the standard bearing; a wireless communication circuit that wirelessly transmits an output from the at least one sensor to outside; and a power supply circuit that converts AC power generated by the generator into direct-current (DC) power usable in the at least one sensor and the wireless communication circuit. The magnetic ring, the stator, and the circuit board are disposed inside an annular space formed by a recess in an end portion of the outer ring and a recess in an end portion of the inner ring. ADVANTAGEOUS EFFECTS OF INVENTION According to the bearing device of the present disclosure, the magnetic ring, the stator, and the circuit board are disposed inside the annular space so as not to overlap with each other in the axial direction of the bearing. Thereby, each component can be disposed inside the annular space, so that the bearing can be reduced in dimensions. Further, in the bearing device of the present disclosure, for example, the magnetic ring is fixed to the inner ring, and the stator is fixed to the outer ring at the position facing the magnetic ring. The displacement of the inner ring and the outer ring in the axial direction of the bearing is relatively small, and the magnetic ring and the stator constitute the generator, with the result that the bearing device is reduced in dimensions and still capable of functioning normally. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a perspective view showing an entirety of a bearing device according to a first embodiment.Fig. 2 is a cross-sectional view along a plane including a rotation axis of a bearing.Fig. 3 is a diagram for illustrating a cage.Fig. 4 is a diagram of the bearing device viewed from the side of a sensor unit.Fig. 5 is an exploded perspective view of the sensor unit.Fig. 6 is