JP2022156079A - Bearing device, spindle device, and electric vertical take-off/landing machine - Google Patents

Abstract

To provide a small-sized bearing device capable of accurately measuring a temperature rise or acceleration with rotations of a bearing.SOLUTION: A bearing device 1 comprises: an outer ring 2; an inner ring 3; a plurality of rolling elements 4; an outer annulus 7; a magnetic ring 8; a cylindrical heat insulation part 11 of which heat conductivity is low and which consists of a non-metal insulator and includes a partition wall 11a extending in a radial direction; and a stator 9 fixed at an opposite side of a bearing B with the partition wall 11a interposed therebetween. The magnetic ring 8 is disposed so as to face the stator 9, and the stator 9 and the magnetic ring 8 constitute a generator G. The bearing device 1 further comprises a circuit board 10 which is fixed in a space closer to the bearing B side than the partition wall 11a. The circuit board 10 includes a power supply circuit 16 which creates a DC power source by performing rectification processing on power generated by the generator G, at least one sensor 17 for detecting a state of the bearing B, and a wireless communication circuit 20 for transmitting output of the at least one sensor 17 to an outside wirelessly.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to bearing devices, spindle devices, and electric vertical take-off and landing aircraft.

It is known to combine a bearing with a generator and use it as a power source for sensors, wireless communication, and the like. A bearing with a wireless sensor disclosed in Japanese Patent Application Laid-Open No. 2006-170624 (Patent Document 1) includes a rolling bearing, a rotation sensor that also serves as a generator, and a wireless transmission circuit that wirelessly transmits the output of the rotation sensor. composed of

The rotation sensor is composed of a magnetic encoder and a magnetic ring in which a coil is accommodated, and the magnetic ring functions as a stator of the rotation sensor of the generator. The rotation sensor is also used as a claw pole generator.

A magnetic ring containing a coil is fitted to the inner diameter surface of the outer member and faces the magnetic encoder. A cover is attached to the outer member to cover the end of the wheel bearing on the inboard side, and an annular ring that wirelessly transmits the output of the rotation sensor is attached to the stepped portion extending from the flange to the small diameter portion of the outer diameter surface of the cover. Wireless transmission means are installed.

The bearing with a wireless sensor disclosed in Japanese Patent Application Laid-Open No. 2019-7580 (Patent Document 2) includes a bearing body, a sensor, a power generation component, a wireless processing circuit, a power supply circuit, a cover, and a cover. and a cooling fan.

In the bearing with a wireless sensor of Patent Document 2, when the inner ring of the bearing body rotates, heat is generated from the raceway grooves of the outer ring and the inner ring, heat is generated from the power generation section (coil) due to power generation, and the temperature of the operating environment rises. etc., the temperature of the bearing rises. In the wireless sensor-equipped bearing of Patent Document 2, radiation fins are provided on the outside of the cover so that the radio circuit, the power supply circuit, etc. attached to the cover do not malfunction due to the influence of heat.

JP 2006-170624 A JP 2019-7580 A

Since the magnetic ring described in Patent Document 1 is directly fitted to the inner diameter surface of the outer member (outer ring) of the wheel bearing, the heat generated by the iron loss of the magnetic ring generated during power generation is directly applied to the outside. The heat is conducted to the side member, and the temperature of the wheel bearing rises. In the wireless sensor-equipped bearing of Patent Document 1, when a temperature sensor is arranged on the outer member in order to monitor temperature rise due to rotation of the wheel bearing, it is difficult to accurately measure the temperature of the outer member. be. In the wireless sensor equipped bearing of Patent Document 1, when measuring the acceleration of the wheel bearing, it is difficult to arrange the acceleration sensor at a position close to the wheel bearing due to the presence of the outer member.

In the bearing with a wireless sensor described in Patent Document 2, a cover formed by press-molding a metal plate is fixed to a groove provided on the outer periphery of the outer ring. A power generation section (yoke, magnet, and coil) is mounted. Therefore, the heat generated by power generation is conducted to the temperature sensor and the bearing mounted on the circuit board. In the wireless sensor equipped bearing described in Patent Document 2, it is difficult for the temperature sensor to detect only the heat generated from the raceway grooves of the outer ring and the inner ring, making it difficult to appropriately determine whether the bearing is abnormal.

The bearing with wireless sensor described in Patent Document 2 has a structure in which a rectangular concave portion is formed on the outer surface of the cover, and the transmitting antenna is arranged in the concave portion. Become. In the wireless sensor-equipped bearing disclosed in Patent Document 2, the cooling fins are formed separately from the cover, which increases the number of parts.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a compact bearing device, a spindle device, and an electric vertical actuator capable of accurately measuring the temperature rise accompanying rotation of the bearing. to provide take-off and landing aircraft.

TECHNICAL FIELD The present disclosure relates to bearing devices that include bearings. A bearing device comprises an outer ring, an inner ring, a plurality of rolling elements arranged between the outer ring and the inner ring, a fixed member fixed to either one of the outer ring and the inner ring, and one of the outer ring and the inner ring. On the other hand, a magnetic ring fixed so as to face the fixed member, and a cylindrical magnetic ring fixed to the fixed member and made of a non-metallic insulator with low thermal conductivity and having a partition wall extending in the radial direction A heat insulating part and a stator fixed on the side opposite to the bearing across the partition are provided. A magnetic ring is arranged to face the stator. The stator and magnetic ring form a generator. The bearing device further includes a circuit board fixed in a space closer to the bearing than the partition wall. The circuit board includes a power supply circuit that rectifies the power generated by the generator to create a DC power supply, at least one sensor that detects the state of the bearing, and a wireless circuit that transmits the output of the at least one sensor to the outside. and communication circuitry.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a small-sized bearing device capable of accurately measuring a temperature rise accompanying rotation of the bearing.

1 is a cross-sectional view of a bearing device according to Embodiment 1; FIG. It is a figure which shows schematic structure of a generator. It is a figure which shows the state which opposingly arranged two magnetic material ring members of the same shape. It is a figure which shows the state which fitted two magnetic material ring members. FIG. 4 is a cross-sectional view of a bearing device of Modification 1 of Embodiment 1; FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5; It is a perspective view explaining the shape of a stator. FIG. 5 is a cross-sectional view showing a schematic configuration of Modification 2 of Embodiment 1; FIG. 9 is a diagram showing an enlarged view of the main part of FIG. 8; 1 is a perspective view of an electric vertical take-off and landing aircraft equipped with a bearing device; FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, when referring to the number, amount, etc., the scope of the present disclosure is not necessarily limited to the number, amount, etc., unless otherwise specified. The same reference numbers are given to the same parts and equivalent parts, and redundant description may not be repeated. It is planned from the beginning to use the configurations in the embodiments in combination as appropriate.

[Embodiment 1]
FIG. 1 is a cross-sectional view of a bearing device according to Embodiment 1 taken along a plane including a rotating shaft. A bearing with a wireless sensor is exemplified as the bearing device 1 shown in FIG. The bearing device 1 includes a bearing B, an outer ring 7 , a magnetic ring 8 , a stator 9 and a circuit board 10 . Bearing B includes outer ring 2 , inner ring 3 , rolling elements 4 , cage 5 and seal 6 . The outer ring 7 is fixed to the inner diameter surface of the outer ring 2 . A heat insulating portion 11 is fixed to the inner diameter surface of the outer ring 7 .

A partition wall 11 a is provided in the heat insulating portion 11 . Two spaces are formed in the heat insulating portion 11 on the side of the bearing B and the side opposite to the bearing. The end face 11b on the bearing B side contacts the end face of the outer ring 7 . A magnetic ring 8 is fixed to the outer diameter surface of the inner ring 3 . The stator 9 is fixed so as to face the magnetic ring 8 in a space on the side opposite to the bearing of the partition wall 11 a of the heat insulating portion 11 . The stator 9 is fixed to the outer ring 7 via the heat insulating portion 11 . In addition, in the bearing device 1, a space may be provided on the bearing B side without providing the end surface 11b. Specifically, in the bearing device 1, the heat insulating portion 11 having an L-shaped cross section that also serves as the partition wall 11a is fixed to the outer ring 7, and a space is provided on the bearing B side by adjusting the depth.

The circuit board 10 is fixed to the end face of the outer ring 7 adjacent to the end face of the outer ring 2 of the bearing B with screws, adhesive, or the like. The circuit board 10 is arranged in the bearing B side space of the partition wall 11 a of the heat insulating portion 11 . A lid 12 is arranged on the outer end surface of the stator 9 . The lid 12 is press-fitted or adhesively fixed to the inner diameter surface of the outer ring 7 . The lid 12 has a two-layer structure having a heat radiation portion 12a and a heat insulation layer 12b. The heat radiating portion 12a is arranged on the inner diameter side in contact with the stator 9, and is made of a metal material with high thermal conductivity (for example, aluminum, copper, iron, etc.). The heat insulating layer 12b is arranged on the outer diameter side and is made of a heat insulating material (for example, an insulating material such as resin) having a low thermal conductivity. Note that the lid 12 may be entirely made of an insulating member (non-conductive member) such as resin.

A generator G is composed of the magnetic ring 8 and the stator 9 . Generator G is a claw pole generator. The bearing B is, for example, a deep groove ball bearing having rolling elements 4 as balls. Here, an inner ring rotating type in which the inner ring 3 is a rotating ring and the outer ring 2 is a stationary ring will be described as an example.

The magnetic ring 8 includes a metal core 8 a and multipolar magnets 8 b and is fixed to the inner ring (rotating ring) 3 . The multipolar magnet 8b is obtained by vulcanizing and adhering a magnetic material, for example, kneading magnetic powder and rubber to the core metal 8a, and then alternately magnetizing N poles and S poles in the circumferential direction.

The stator 9 includes two identically shaped magnetic ring members 13 (13-1, 13-2), a bobbin 14 and a coil 15. As shown in FIG. The winding of the coil 15 is wound around the bobbin 14 a plurality of times in the circumferential direction. Although an example using the bobbin 14 is shown here, the stator 9 may be configured using an air-core coil that does not use the bobbin 14 .

The circuit board 10 includes a power supply circuit 16 that rectifies the AC power generated by the generator G and converts it to DC, a sensor 17 that monitors the state of the bearing B, and a wireless circuit that transmits the output of the sensor 17 to the outside. A communication circuit 20 is implemented. Sensor 17 includes temperature sensor 18 and acceleration sensor 19 . The temperature sensor 18 is mounted on the back surface of the circuit board 10 so that it can be arranged at a position close to the bearing B. As shown in FIG. The temperature sensor 18 is inserted into a recess 7a (groove or hole) provided in the end face of the outer ring 7. As shown in FIG.

The winding start and winding end portions (not shown) of the coil 15 are connected to the circuit board 10 via a groove 12c provided on the side surface of the lid 12 and a groove 11c provided on the outer periphery of the heat insulating portion 11. FIG. AC power output from the generator G as the inner ring 3 rotates is converted into DC power by the power supply circuit 16 . A protective film such as resin may be applied to the surface of the circuit board 10 .

The circuit board 10 on which the wireless communication circuit 20 is mounted is arranged to face the heat insulation section 11 . By using an insulator (non-conductive material) such as resin with low thermal conductivity as the heat insulating part 11 and using an insulating material for the heat insulating layer 12b formed on the outer peripheral surface of the lid 12, the outer ring 7 and A cylindrical insulator is formed between it and the stator 9 . As a result, the wireless communication circuit 20 has a structure that is not sealed with a conductive material such as metal, so wireless communication is possible using the antenna section 20a. Alternatively, the wireless communication circuit 20 may be formed as a separate substrate (not shown) and arranged between the lid 12 and the stator 9 . In this case, the material of the portion of the lid 12 facing the antenna portion 20a of the wireless communication circuit 20 is preferably an insulating member.

The stator 9 of the generator G is thermally insulated from metal members such as the outer ring 7 by the heat insulating portion 11 . When the magnetic ring 8 fixed to the inner ring 3 rotates to generate electricity, the heat generated by the iron loss of the stator 9 is not directly conducted to the bearing B side. Therefore, only the heat generated by the rotation of the bearing B can be detected by the temperature sensor 18 .

The seal 6 is not arranged on the side of the bearing B to which the magnetic ring 8 is fixed. However, since the lid 12 is provided to cover the magnetic ring 8 and the stator 9, and the gap between the parts is narrowed, a labyrinth seal (non-contact seal) structure is provided, which can prevent foreign matter from entering.

The lid 12 is formed in a two-layer structure having a heat radiating portion 12a with high thermal conductivity and a heat insulating layer 12b with low thermal conductivity around its periphery. The cover 12 is provided with a folded portion 12d that wraps around the inner diameter side of the metal core 8a of the magnetic ring 8 in order to increase the volume and surface area of the heat radiating portion 12a for cooling the stator 9. As shown in FIG. The sealing performance of the lid 12 is improved by the folded portion 12d.

Since the end surface of the stator 9 is in contact with the heat radiating portion 12a, the heat generated by the stator 9 can be efficiently radiated to the outside by the heat radiating portion 12a. The heat insulating layer 12b prevents the temperature of the heat radiating portion 12a from being directly transmitted to the outer ring 7, so that the heat generated by the stator 9 can be prevented from affecting the bearing B. By forming grooves (not shown) on the outer surface of the heat radiating portion 12a to increase the surface area, heat radiation can be further improved.

FIG. 2 is a diagram showing a schematic configuration of the generator G. As shown in FIG. Generator G is a claw pole generator. The magnetic rotor is composed of a ring-shaped multipolar magnet 8b. The stator 9 is composed of a coil 15 and a magnetic yoke surrounding it. The magnetic yoke is composed of magnetic ring members 13 (13-1, 13-2). The magnetic flux emitted from the N pole of the multipolar magnet 8b enters the magnetic yoke from the magnetic pole claw 13b, goes around the coil, and enters the S pole of the multipolar magnet 8b from the adjacent claw 13b. When the positions of the N pole and the S pole of the multipolar magnet 8b are switched depending on the rotation angle of the magnetic rotor, the direction of the magnetic flux is reversed. An alternating voltage is generated across the coil 15 by the alternating magnetic field thus generated.

The structure of the stator 9 will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is a diagram showing a state in which two magnetic ring members 13 having the same shape are arranged facing each other. Actually, the space sandwiched between the two magnetic ring members 13-1 and 13-2 accommodates the bobbin 14 around which the coil 15 is wound. The bobbin 14 used is omitted. FIG. 4 is a diagram showing a state in which two magnetic ring members 13 are fitted together.

At the inner peripheral end of the magnetic ring member 13 (13-1, 13-2), grooves 13a and claws 13b opening toward the shaft are alternately formed in a comb shape. A concave portion 13c and a convex portion 13d are formed on the end face 13f of the magnetic ring member 13 (13-1, 13-2). In the magnetic ring member 13, when two magnetic ring members 13-1 and 13-2 having the same shape are opposed to each other and the claws 13b are arranged alternately, one magnetic ring The concave portion 13c and the convex portion 13d are engaged by designing such that the convex portion 13d of the other magnetic ring member 13-2 is arranged with respect to the concave portion 13c of the member 13-1.

The concave portions 13c and the convex portions 13d provided on the end face 13f of each magnetic ring member 13 are fitted so that the claws 13b provided on each magnetic ring member 13 are alternately arranged. By doing so, it becomes easy to dispose the magnetic ring members 13 so that the gaps between the claws 13b and the claws 13b of the magnetic ring members 13 are uniform. Further, since a plurality of concave portions 13c and convex portions 13d are arranged in the circumferential direction, the positions of the magnetic ring members 13 can be fixed without being displaced in the circumferential direction.

The N pole and S pole of the magnetic ring 8 have the same number of magnetized poles and the same magnetic pole pitch. A hole 13e provided in the side surface of the magnetic ring member 13 is used to pull out the end of the coil 15 to the outside.

A circuit board 10 is fixed at a position near the bearing B in the bearing device 1 shown in FIG. Therefore, the bearing device 1 can measure the acceleration caused by the vibration caused by the bearing B by using the acceleration sensor 19 mounted on the circuit board 10 before the vibration attenuates. In the abnormality diagnosis based on the measured acceleration, the diagnosis can be made using a signal with little attenuation, so that the abnormality of the bearing B can be accurately diagnosed.

In the bearing device 1 , the stator 9 and the outer ring 7 are thermally insulated by the heat insulating portion 11 . Therefore, the temperature sensor 18 mounted on the circuit board 10 can accurately monitor the temperature rise of the bearing B without being affected by the heat generated by the stator 9 . The bearing device 1 is provided with a lid 12 having a heat radiating portion 12a with excellent heat conductivity and good heat dissipation at a portion that abuts on the outer end face of the stator 9. Therefore, the heat generated in the stator 9 is effectively dissipated to the outside. can be released The lid 12 of the bearing device 1 is provided with a heat insulating layer 12b made of an insulating material with low thermal conductivity and excellent heat insulation on the outer periphery of the heat radiating portion 12a. It is possible to prevent the heat generated in the stator 9 from affecting the bearing B.

When the sensor output is wirelessly communicated, it is preferable that at least the antenna portion 20a of the circuit board 10 on which the wireless communication circuit 20 is mounted face the heat insulating portion 11 at a position that does not overlap the stator 9 in the axial direction. A ring-shaped insulating layer is formed between the outer ring 7 and the stator 9 by using an insulating material (non-conductive material) such as resin for the heat insulating portion 11 and the heat insulating layer 12b. By using an insulator layer that allows radio waves to pass through, the wireless communication circuit 20 has a structure that is not sealed with a conductive material such as metal, thereby enabling wireless communication.

For example, when Bluetooth Low Energy (registered trademark) (frequency of 2.4 GHz, wavelength λ of about 125 mm) is used as the communication standard of the wireless communication circuit 20, if there is an insulator gap of λ/2 or more, the bearing device 1 Radio waves can be emitted to the outside.

In the bearing device 1, the claw-pole generator was described as an example of the generator G, but other generators may be used.

In the bearing device 1 , a heat insulating coating may be applied to the surface of the magnetic ring 8 facing the stator 9 to suppress temperature rise due to radiant heat from the stator 9 and to suppress heat transfer to the inner ring 3 .

In the bearing device 1, the outer ring 2 of the bearing B may be fixed to the rotating member and the inner ring 3 may be fixed to the stationary member. Instead of fixing the outer ring 7 to the inner diameter surface of the outer ring 2 of the bearing B, the bearing device 1 may have a configuration in which the end portion of the outer ring 2 is extended in the axial direction and the outer ring 7 is omitted.

[Modification 1 of Embodiment 1]
5 to 7 are diagrams illustrating a bearing device 1A of Modification 1 of Embodiment 1. FIG. FIG. 5 is a cross-sectional view of a bearing device 1A of Modification 1 of Embodiment 1. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5. FIG. In order to make the drawing easier to understand, the bobbin 14 is represented by a two-dot chain line, and the coil 15 is omitted. FIG. 7 is a perspective view explaining the shape of the stator 9A.

In the bearing device 1A shown in FIG. 5, the circuit board 10 is fixed to the end surface of the outer ring 7 so that the circuit board 10 mounted with the sensor 17 can be arranged close to the bearing B. As shown in FIG. As a fixing method, screws, an adhesive, or the like can be used. Since the modification 1 employs fixing with an adhesive, it can be fixed in a small space.

As shown in FIG. 5, the heat insulating portion 11A has an L-shaped cross section. As shown in FIG. 6, the heat insulating portion 11A also has a C-shape in which a notch portion 11Ad is formed on a part of the circumference to avoid interference with the circuit board 10. As shown in FIG. The notch 11Ad is the range of C in FIG. The partition wall 11Aa is a part of the heat insulating portion 11A and is arranged so as to contact the end surface of the outer ring 7 . As shown in FIG. 6, the circuit board 10 is arranged in the region of the notch portion 11Ad of the heat insulating portion 11A when viewed from the axial direction.

As shown in FIG. 7, in the stator 9A, part of the magnetic ring member 13A (13A-1, 13A-2) is removed so as not to interfere with the circuit board . The structure has a removed portion 9A1, and the bobbin 14 is exposed. The removed portion 9A1 is the range of R in FIG.

As shown in FIG. 6, the range C of the cutout portion 11Ad of the heat insulating portion 11A is smaller than the range R of the removed portion 9A1 of the stator 9A. In this case, since the magnetic ring member 13A and the circuit board 10 do not directly face each other, radiant heat transmitted from the magnetic ring member 13A to the circuit board 10 can be suppressed. In the removing portion 9A1, the bobbin 14 and the circuit board 10 face each other. The bobbin 14 is made of an insulator such as resin having a relatively low thermal conductivity. Thereby, the heat generated by the coil 15 can be suppressed from being directly radiated to the circuit board 10 .

A lid 12 is arranged on the outer end surface of the stator 9A. The lid 12 is fixed to the inner diameter surface of the outer ring 7 . The lid 12 is formed in a two-layer structure having a heat radiation portion 12a and a heat insulation layer 12b. The heat radiating portion 12a is arranged in a portion that abuts on the outer end face of the stator 9A, and has excellent thermal conductivity and good heat radiation. The heat insulating layer 12b is arranged on the outer periphery of the heat radiating portion 12a, and has low thermal conductivity and excellent heat insulating properties. Since the end face of the stator 9A is in contact with the heat radiating portion 12a, the heat generated in the stator 9A can be efficiently radiated to the outside by the heat radiating portion 12a. Since the temperature of the heat radiating portion 12a is not directly transmitted to the outer ring 7 by the heat insulating layer 12b, the heat generated in the stator 9A can be prevented from affecting the bearing B.

With the structure of the bearing device 1A, since no conductive member is arranged near the outer side facing the wireless communication circuit 20 mounted on the circuit board 10, it is possible to radiate radio waves to the outside. It becomes possible to perform wireless communication. In the bearing device 1A of Modified Example 1 of Embodiment 1, the stator 9A can be arranged closer to the bearing B, so that the axial width of the outer ring 7 can be shortened. Therefore, the size reduction of the bearing device 1A can be realized.

[Modification 2 of Embodiment 1]
The bearing devices 1 and 1A described above were configured using single-row bearings. The bearing devices 1 and 1A can also be applied to a bearing device using multiple rows of bearings used in a spindle device or the like. FIGS. 8 and 9 are diagrams for explaining Modification 2 of Embodiment 1 in which the configuration of the present disclosure is applied to bearing device 90 of spindle device 50. FIG. FIG. 8 is a cross-sectional view showing a schematic configuration of Modification 2 of Embodiment 1. As shown in FIG. FIG. 9 is an enlarged view of the main part S of FIG. 8, mainly showing the bearing device 90. As shown in FIG.

A spindle device 50 shown in FIG. 8 is used, for example, as a built-in motor type spindle device for a machine tool. In this case, a motor 52 is incorporated at one end of a main shaft 51 supported by a spindle device 50 for a machine tool main shaft, and a cutting tool such as an end mill (not shown) is connected to the other end.

8 and 9, the spindle device 50 includes a bearing 53 (53a, 53b), a spacer 54 arranged adjacent to the bearings 53a, 53b, a motor 52, and a bearing 55. As shown in FIG. The main shaft 51 is rotatably supported by a plurality of bearings 53 a and 53 b provided in a housing 57 embedded in the inner diameter of the outer cylinder 56 . The bearing 53a includes an inner ring 53ia, an outer ring 53ga, rolling elements Ta, and a retainer Rta. The bearing 53b includes an inner ring 53ib, an outer ring 53gb, rolling elements Tb, and a retainer Rtb. The spacer 54 includes an inner ring spacer 54i and an outer ring spacer 54g. Wireless communication will be discussed later. In order to enable wireless communication, it is preferable that the rolling elements Ta and Tb be made of ceramic, which is an insulator, and the retainers Rta and Rtb be made of resin.

An inner ring 53ia of a bearing 53a and an inner ring 53ib of a bearing 53b, which are spaced apart in the axial direction, are fitted to the main shaft 51 in an interference fit state (press fit state). An inner ring spacer 54i is arranged between the inner ring 53ia and the inner ring 53ib, and an outer ring spacer 54g is arranged between the outer ring 53ga and the inner ring 53gb.

As will be described later, the bearings 53a and 53b are bearings that can be preloaded by an axial force, and angular ball bearings, deep groove ball bearings, tapered roller bearings, or the like can be used. Angular ball bearings are used in the bearing device 90 shown in FIGS. 8 and 9, and two bearings 53a and 53b are installed in a back-to-back combination (DB combination).

The outer ring spacer 54g is axially divided into a first outer ring spacer 54g1 and a second outer ring spacer 54g2. A stator 9 of the generator G is fixed between the first outer ring spacer 54g1 and the second outer ring spacer 54g2. A magnetic ring 8 is fixed to the outer peripheral surface of the inner ring spacer 54i. As in FIG. 2, the generator G is arranged such that the claws 13b of the stator 9 and the multipolar magnets 8b of the magnetic ring 8 face each other with a gap therebetween. Generator G is a claw pole generator. Here, a structure in which the outer ring spacer 54g is divided into two has been described, but a structure in which the outer ring spacer 54g is not divided may also be used.

The magnetic ring 8 includes a metal core 8a and a multipolar magnet 8b. The multipolar magnet 8b is formed by vulcanizing and adhering a magnetic material, for example, kneading magnetic powder and rubber to the core metal 8a, and then alternately magnetizing the N pole and the S pole, and is fixed to the inner ring spacer 54i. be done. The stator 9 includes two identically shaped magnetic ring members 13 (13-1, 13-2), a bobbin 14, and a coil 15. As shown in FIG. The winding of the coil 15 is wound around the bobbin 14 a plurality of times in the circumferential direction. Modification 2 shows an example using the bobbin 14, but an air-core coil that does not use the bobbin 14 may be used.

A heat insulating portion 71 (71a, 71b) is provided between the stator 9 and the outer ring spacer 54g. The bearing device 90 has a structure in which heat generated in the stator 9 due to iron loss or the like is not directly conducted to the outer ring spacer 54g. In the bearing device 90 , a cylindrical heat radiating portion 72 having good thermal conductivity is inserted so as to come into contact with one side surface of the stator 9 . Heat generated by the stator 9 can be efficiently radiated to the outside by the heat radiation portion 72 . The stator 9 and the heat radiating portion 72 are arranged on the inner diameter surface of the first heat insulating portion 71a having an L-shaped cross section. A second heat insulating portion 71b is arranged between the heat radiating portion 72 and the side surface of the second outer ring spacer 54g2.

The outer ring spacer 54g and the stator 9 are thermally insulated by the heat insulating portion 71 (71a, 71b). An uneven portion 72 a is formed on the inner diameter surface of the heat radiating portion 72 . The heat radiation portion 72 has an increased surface area due to the uneven portion 72a, thereby improving the heat radiation performance. A heat radiating portion may be arranged on the opposite side of the stator 9 with respect to the heat radiating portion 72 . The heat radiation part 72 may be provided with a flow path (not shown) through which a cooling medium can pass. By flowing the bearing cooling air through the flow path of the heat radiating portion 72, the heat radiating performance of the bearing device 90 can be further improved.

A groove 54g1a is formed in the end surface of the first outer ring spacer 54g1. The circuit board 10 is mounted inside the groove 54g1a. The circuit board 10 includes a power supply circuit 16 that rectifies the AC power generated by the generator G and converts it to DC, a sensor 17 that monitors the state of the bearing device 90, and a sensor 17 that transmits the output of the sensor 17 wirelessly to the outside. A wireless communication circuit 20 is mounted. The ends 15a and 15b of the coil 15 are connected to the circuit board 10 through the hole 71a1 of the first heat insulating portion 71a and the hole 54g1b of the first outer ring spacer 54g1. The holes 71a1 and 54g1b are preferably sealed with a sealing material after wiring to prevent oil or the like from entering the circuit board 10 side.

AC power output from the electric machine G as the main shaft 51 rotates is converted into DC power by the power supply circuit 16 . A lid 73 as a protective member for protecting the circuit board 10 is formed of a non-metal (non-conductive member) insulator such as resin, and is fixed to the groove 54g1a. Note that the bearing device 90 may seal the inside of the groove 54g1a including the circuit board 10 with a resin mold material instead of the lid 73. FIG.

As the sensor 17, a temperature sensor 18, an acceleration sensor 19, a load sensor 21, etc. are mounted as required. Each sensor output is wirelessly transmitted to the outside using the wireless communication circuit 20 .

The single row rolling bearing 55 is a cylindrical roller bearing. The bearings 53a and 53b, which are angular ball bearings, support the radial and axial loads acting on the spindle device 50. As shown in FIG. A single row bearing 55, which is a cylindrical roller bearing, supports the radial loads acting on the spindle device 50 for the machine tool spindle.

A cooling medium flow path GV is formed in the housing 57 . The bearings 53a and 53b can be cooled by flowing the cooling medium through the cooling medium flow path GV. When grease-lubricated bearings are used as the bearings 53a and 53b, no lubricating oil supply path is required. . Note that the lubricating oil supply path is not shown here.

When assembling, the front cover 60, the bearing 53a, the spacer 54, the bearing 53b, and the spacer 58 are first inserted into the main shaft 51 in this order, and an initial preload is applied by tightening the nut 59. As shown in FIG. Thereafter, the main shaft 51 to which the bearings 53a and 53b are attached is inserted into the housing 57 until the right side of the outer ring 53gb of the bearing 53b in FIG. Finally, the main shaft 51 is fixed to the housing 57 by pushing the outer ring 53ga of the left bearing 53a with the front cover 60 .

By tightening the nut 59, a force acts on the end surface of the inner ring 53ib of the bearing 53b through the spacer 58, and the inner ring 53ib is pressed toward the inner ring spacer 54i. This force is transmitted to the inner ring 53ib, the rolling elements Tb, and the outer ring 53gb, giving preload between the raceway surfaces of the inner ring 53ib and the outer ring 53gb and the rolling elements Tb, and is also transmitted from the outer ring 53gb to the outer ring spacer 54g.

This force is transmitted to the outer ring 53ga, the rolling elements Ta, and the inner ring 53ia in the bearing 53a, and also applies preload between the raceway surfaces of the inner ring 53ia and the outer ring 53ga of the left bearing 5a and the rolling elements Ta. The preload applied to the bearings 53a, 53b is determined, for example, by the amount of movement limited by the dimensional difference between the width of the outer ring spacer 54g and the width of the inner ring spacer 54i.

In the single-row bearing 55 shown in FIG. 8, the inner ring 55a is axially positioned by a tubular member 61 fitted to the outer periphery of the main shaft 51 and an inner ring retainer 62. As shown in FIG. The inner ring retainer 62 is retained by a nut 63 screwed onto the main shaft 51 . An outer ring 55 b of the bearing 55 is sandwiched between a positioning member 65 and a positioning member 66 fixed to the end member 64 . The inner ring 55a slides integrally with respect to the end member 64 as the main shaft 51 expands and contracts.

A motor 52 for driving the main shaft 51 is arranged at an axially intermediate position between the bearing 53b and the single-row bearing 55 in the space 67 formed between the main shaft 51 and the outer cylinder 56. . A rotor 68 of the motor 52 is fixed to the cylindrical member 61 fitted to the outer circumference of the main shaft 51 , and a stator 69 of the motor 52 is fixed to the inner circumference of the outer cylinder 56 . A cooling medium flow path for cooling the motor 52 is not shown here.

As described above, the circuit board 10 on which the generator G, the power supply circuit 16, the sensor 17, the wireless communication circuit 20 and the like are mounted is arranged on the outer ring spacer 54g. Since the bearing device 90 can wirelessly transmit the output of the sensor 17 to the outside using the generated power, it is possible to monitor the operating status of the spindle device 50 . The bearing device 90 may determine the presence or absence of an abnormality within the circuit board 10 from each sensor output, and wirelessly transmit the determination result.

In order to allow the radio wave transmitted from the wireless communication circuit 20 to pass through the gap between the outer ring 53ga and the inner ring 53ia of the bearing 53a, at least the material of the rolling elements Ta of the bearing 53 is ceramic, which is an insulator. It is preferable to use resin, which is an insulator, for the container Rta. After that, the radio waves pass through a labyrinth seal gap 70 formed between the main shaft 51 and the front cover 60 and are emitted to the outside. It should be noted that simplifying the structure of the labyrinth seal and enlarging the gap 70 is preferable for the radio wave environment. If radio waves have directivity, a wireless transmitter/receiver (not shown) or repeater may be provided below the main shaft.

The stator 9 of the generator G mounted on the spindle device 50 is thermally insulated from the outer ring spacer 54g by the heat insulating portion 71 . Therefore, in the bearing device 90, the heat generated by the iron loss of the stator 9 during operation of the spindle device 50 is suppressed from being conducted to the outer ring spacer 54g. can do. Thereby, the abnormality of the bearing 53 can be detected more accurately. In the bearing device 90, since the wiring is not led out from the outer ring spacer 54g, there is no need to process a groove for drawing out the wiring on the inner diameter side of the housing 57, thereby improving the assembling efficiency.

[Configuration of electric vertical take-off and landing aircraft]
In recent years, so-called flying cars, which are capable of flying, have attracted attention as means of transportation in place of automobiles. Flying cars are expected to be used in various situations such as transportation within and between regions, tourism and leisure, emergency medical care, and disaster relief.

A vertical take-off and landing aircraft (VTOL) is attracting attention as a flying car. Vertical take-off and landing aircraft can ascend and descend vertically between the sky and the takeoff and landing site, so they do not require a runway and are highly convenient. In particular, in recent years, due to social demand for reducing CO ₂ , an electric vertical take-off and landing aircraft (eVTOL) that flies with a battery and a motor has become the mainstream of development.

The bearing device of the above embodiment may be mounted on such an electric vertical take-off and landing aircraft. The configuration of an electric vertical take-off and landing aircraft equipped with the bearing device 1 according to Embodiment 1 will be described as an example with reference to FIG. 10 .

As shown in FIG. 10, the electric vertical take-off and landing aircraft 101 is a multicopter having a main body 102 located in the center of the aircraft body and four drive units 103 arranged in the front, rear, left and right. The drive unit 103 is a device that generates lift and propulsion for the electric vertical take-off and landing aircraft 101 . The electric vertical take-off and landing aircraft 101 flies by driving the drive unit 103 . The electric vertical take-off and landing aircraft 101 may have a plurality of driving units 103, and the number is not limited to four.

The body portion 102 has a living space in which passengers (for example, about one or two people) can board. This living space is equipped with an operating system for determining the direction of travel and altitude, as well as instruments that indicate altitude, speed, flight position, and so on. Four arms 102a extend from the main body portion 102, and a driving portion 103 is provided at the tip of each arm 102a. The arm 102a is integrally provided with an annular portion that covers the rotating circumference of the rotor blade 104 in order to protect the rotor blade 104. As shown in FIG. A skid 102b is provided at the bottom of the main body 102 to support the aircraft during landing.

The drive unit 103 has a pair of upper and lower rotor blades 104 and a motor device 105 that rotates the rotor blades 104 . In the drive unit 103, a pair of upper and lower rotor blades 104 are provided on both sides in the axial direction with the motor device 105 interposed therebetween. Each of the pair of upper and lower rotor blades 104 has two blades extending radially outward.

The body portion 102 is provided with a battery (not shown) and a control device (not shown). Controllers are also called flight controllers. Control of the electric vertical take-off and landing aircraft 101 is performed by the control device, for example, as follows. Based on the difference between the current attitude and the target attitude, the control device outputs a rotation speed change command to the motor device 105 that should adjust the lift force. Based on the command, an amplifier provided in motor device 105 adjusts the amount of electric power sent from the battery to motor device 105, and the rotation speed of motor device 105 (and rotor blade 104) is changed. In addition, the adjustment of the number of rotations of the motor devices 105 is performed simultaneously for the plurality of motor devices 105, thereby determining the attitude of the airframe.

When the bearing device 90 of the second modification of the first embodiment is used for the motor device 105, the main shaft 51 is applied as a rotating shaft, the above-described upper rotating blade is attached to one end side of the rotating shaft, and the other end side of the rotating shaft The rotor 68 of the motor device 105 may be attached. The rotor 68 is arranged to face a stator 69 fixed to the tubular member 61 and is rotatable with respect to the stator 69 . It should be noted that the motor device 105 can employ a configuration of an outer rotor type brushless motor or an inner rotor type brushless motor.

The motor device 105 has an outer cylinder 56, a housing 57, a rotor 68, a stator 69, an amplifier (not shown), and two bearings 53a and 53b. A cooling medium flow path is provided between the outer cylinder 56 and the housing 57 . Excessive temperature rise is prevented by flowing the cooling medium through this channel. The material of outer cylinder 56 and housing 57 is not particularly limited, and may be, for example, iron-based material, CFRP (carbon fiber reinforced plastic), or the like.

When the motor device 105 is used as the bearing device 90 , the bearing device 90 rotatably supports the rotating shaft inside the outer cylinder 56 . The bearing device 90 has a structure in which heat generated by the stator 9 due to iron loss or the like is not directly conducted to the outer ring spacer 54g. A groove 54g1a is formed in the end surface of the first outer ring spacer 54g1. The circuit board 10 is mounted inside the groove 54g1a. The circuit board 10 includes a power supply circuit 16 that rectifies the AC power generated by the generator G and converts it to DC, a sensor 17 that monitors the state of the bearing device 90, and a sensor 17 that transmits the output of the sensor 17 wirelessly to the outside. A wireless communication circuit 20 is implemented.

It should be noted that the bearing configuration in the driving portion may be another configuration. In FIG. 10, the rotating shaft of the motor device 105 and the rotating shaft of the rotor blade 104 are the same rotating shaft, but the rotating shaft of the motor device 105 and the rotating shaft of the rotor blade 104 are connected via a transmission mechanism. It may be a configuration. In this case, the bearing device that supports the rotating shaft in the drive unit may be the bearing device that supports the rotating shaft of the motor device 105 or the bearing device that supports the rotating shaft of the rotor blade.

(summary)
The present disclosure relates to a bearing device 1 comprising a bearing. The bearing device 1 includes an outer ring 2, an inner ring 3, a plurality of rolling elements 4 arranged between the outer ring 2 and the inner ring 3, and an outer ring 7 fixed to one of the outer ring 2 and the inner ring 3. , a magnetic ring 8 fixed to the other of the outer ring 2 and the inner ring 3 so as to face the outer ring 7, and a non-metallic insulator having low thermal conductivity and being fixed to the outer ring 7 and a cylindrical heat insulating portion 11 having a partition wall 11a extending in the radial direction, and a stator 9 fixed on the opposite side of the bearing B with the partition wall 11a interposed therebetween. The magnetic ring 8 is arranged to face the stator 9 , and the stator 9 and the magnetic ring 8 constitute a generator G. The bearing device 1 further includes a circuit board 10 fixed in a space closer to the bearing B than the partition wall 11a. The circuit board 10 includes a power supply circuit 16 that rectifies the power generated by the generator G to generate a DC power supply, at least one sensor 17 that detects the state of the bearing B, and wirelessly transmits the output of the at least one sensor 17. and a wireless communication circuit 20 for transmitting to the outside at.

By providing such a configuration, the stator 9 and the bearing B of the generator G are thermally insulated by the heat insulating portion 11, so that the heat generated by the iron loss of the stator 9 is transferred to the bearing B and the outer ring 7. Conduction can be reduced. By arranging the temperature sensor 18 as the sensor 17 in the vicinity of the bearing B, only the temperature rise caused by the rotation of the bearing B can be accurately detected. By arranging the acceleration sensor 19 as the sensor 17 near the bearing B, it is possible to measure the acceleration caused by the vibration caused by the bearing B before the vibration attenuates. Since the bearing device 1 has a simple structure, it can be downsized.

Preferably, a heat radiating portion 12a made of a material having a high thermal conductivity and arranged so as to abut against the stator 9, and a heat insulating layer 12b made of a heat insulating member having a low heat conductivity, arranged on the outer peripheral surface of the heat radiating portion 12a. And further comprising. The heat insulating layer 12b contacts the outer ring 7. As shown in FIG.

With such a configuration, the bearing device 1 can efficiently radiate the heat generated by the stator 9 to the outside through the heat radiating portion 12a. , so that the heat generated by the stator 9 does not affect the bearing B.

Preferably, one of outer ring 2 and inner ring 3 functions as a stationary ring of bearing device 1 . The circuit board 10 is fixed to the outer ring 7 in a space formed between the end face of the outer ring 7 that contacts the end face of the stationary ring and the partition wall 11 a of the heat insulating portion 11 .

With such a configuration, the circuit board 10 is arranged in the vicinity of the bearing B and is thermally insulated by the partition wall 11a of the heat insulating portion 11, so that the temperature rise or acceleration due to the rotation of the bearing B can be detected accurately. can be measured to

Preferably, the wireless communication circuit 20 internally includes an antenna section 20a. The antenna section 20A is arranged at a position that does not axially overlap with the stator 9 and is arranged at a position facing the heat insulation section 11 .

With such a configuration, radio waves can be emitted to the outside of the bearing device 1 without the antenna portion 20a being affected by conductive materials such as metal.

Preferably, in the bearing device 1A, a notch portion 11Ad formed in a part of the outer periphery of the heat insulating portion 11A and a circumferential portion of the magnetic ring member 13 constituting the stator 9A are removed so that the bobbin 14 is exposed. The circuit board 10 is arranged in the region of the notch portion 11Ad overlapping the removed portion 9A1.

With such a configuration, the bearing device 1A can have the stator 9A closer to the bearing B, so that the axial width of the outer ring 7 can be shortened and the size can be reduced.

Preferably, in the bearing device 90, the outer ring spacer 54g serves as a fixed member.
With such a configuration, the bearing device 90 can accurately measure the temperature rise or acceleration accompanying the rotation of the bearing 53 in the configuration including the bearings 53a and 53b.

Preferably, one of outer ring 2 and inner ring 3 functions as a stationary ring of bearing device 90 . The circuit board 10 is fixed inside a groove 54g1a formed in one end of the outer ring spacer 54g adjacent to the stationary ring. The lid 73 as a protective member that protects the circuit board 10 and the plurality of rolling elements Ta facing the lid 73 are made of an insulator. A gap 70 is provided between the front cover 60 that contacts the other end of the stationary ring of the bearing 53 and the main shaft 51 that is supported by the front cover 60 and the bearing 53 .

With such a configuration, the bearing device 90 can emit radio waves emitted from the wireless communication circuit 20 to the outside from the gap 70 of the labyrinth seal formed between the main shaft 51 and the front cover 60 .

Preferably, the bearing device 90 may be applied to the spindle device 50 .
With such a configuration, the spindle device 50 can accurately measure the temperature rise or acceleration accompanying the rotation of the bearing 53 .

Preferably, the bearing device 1 may be applied to an electric vertical take-off and landing aircraft 101 that includes rotor blades 104 rotatably supported by the bearing device 1 and that flies by rotating the rotor blades 104 .

With such a configuration, the electric vertical take-off and landing aircraft 101 can accurately measure the temperature rise or acceleration associated with the rotation of the bearings.

The embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present disclosure is indicated by the scope of claims rather than the description of the above-described embodiments, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

1, 1A, 90 Bearing device 2, 53ga, 53gb, 55b Outer ring 3, 53ia, 53ib, 55a Inner ring 4, Ta, Tb Rolling element 5, Rta, Rtb Cage 5a, 5b, 53, 53a, 53b, 55, B bearing 6 seal 7 outer ring 8 magnetic ring 8a core metal 8b multipolar magnet 9, 9A stator 9A1 removed portion 10 circuit board 11, 11A, 71 heat insulating portion 11Aa, 11a partition wall 11Ad notch 12,73 lid 12a,72 heat radiation part 12b heat insulating layer 13,13A magnetic ring member 14 bobbin 15 coil 16 power supply circuit 17 sensor 18 temperature sensor 19 acceleration Sensor 20 Wireless communication circuit 20a Antenna part 50 Spindle device 51 Main shaft 54g Outer ring spacer 54i Inner ring spacer 60 Front cover 71a First heat insulating part 71b Second heat insulating part G Generator.

Claims (9)

A bearing device comprising a bearing,
an outer ring;
inner ring;
a plurality of rolling elements arranged between the outer ring and the inner ring;
a fixing member fixed to one of the outer ring and the inner ring;
a magnetic ring fixed to the other of the outer ring and the inner ring so as to face the fixing member;
a cylindrical heat insulating portion fixed to the fixing member, made of a non-metallic insulator having a low thermal conductivity, and having a partition wall extending in a radial direction;
a stator fixed on the side opposite to the bearing across the partition;
The magnetic ring is arranged to face the stator,
the stator and the magnetic ring form a generator,
The bearing device further includes a circuit board fixed in a space closer to the bearing than the partition wall,
The circuit board is
a power supply circuit that rectifies the power generated by the generator to generate a DC power supply;
at least one sensor for detecting the condition of the bearing;
a wireless communication circuit that wirelessly transmits the output of the at least one sensor to the outside. a heat radiating portion arranged to abut on the stator and made of a material with high thermal conductivity;
a heat insulating layer disposed on the outer peripheral surface of the heat radiating portion and made of a heat insulating member having low thermal conductivity;
2. The bearing device according to claim 1, wherein said heat insulating layer abuts said fixing member. one of the outer ring and the inner ring functions as a stationary ring of the bearing device;
3. The circuit board is fixed to the fixed member in a space formed between the end face of the fixed member that contacts the end face of the stationary ring and the partition wall of the heat insulating portion. The bearing device according to . The wireless communication circuit includes an antenna section inside,
The bearing device according to any one of claims 1 to 3, wherein the antenna section is arranged at a position that does not axially overlap with the stator and is arranged at a position facing the heat insulating section. A notch portion formed in a part of the outer periphery of the heat insulating portion and a removed portion in which a bobbin is exposed by removing a part in the circumferential direction of the magnetic ring member constituting the stator overlap,
5. The bearing device according to any one of claims 1 to 4, wherein the circuit board is arranged in the area of the cutout. 3. The bearing device according to claim 1, wherein said fixed member is an outer ring spacer. one of the outer ring and the inner ring functions as a stationary ring of the bearing device;
The circuit board is fixed inside a groove formed in one end of the outer ring spacer adjacent to the stationary ring,
the protective member that protects the circuit board and the plurality of rolling elements facing the protective member are made of an insulator,
7. The bearing device according to claim 6, wherein a gap is provided between a lid abutting on the other end of said stationary ring of said bearing and a main shaft supported by said lid and said bearing. A spindle device comprising the bearing device according to any one of claims 1 to 7. a bearing device according to any one of claims 1 to 7;
a rotor rotatably supported by the bearing device,
An electric vertical take-off and landing aircraft that flies by rotating the rotor blades.

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