JP7705724B2 - Bearing device with absolute type rotation sensor - Google Patents

Description

The present invention relates to a bearing device equipped with an absolute rotation sensor.

Bearing devices equipped with absolute rotation sensors that enable highly accurate control are used as bearings that rotatably support the joints of industrial robots. For example, a bearing device with an absolute rotation sensor has been proposed that has one origin detection unit and two absolute angle detection units (see, for example, Patent Document 1).

This bearing device requires a large number of parts, including three sensors and cables connected to these sensors, and the two absolute angle detection units must be positioned so that they have a 90° phase difference from each other, making the assembly process complicated.

As a result, it is possible to use a double track type rotation sensor as an absolute rotation sensor to be combined with a bearing. This double track type rotation sensor has two rows of magnetic tracks on the circumferential surface of an annular core, one for angle detection (main track) and one for phase difference detection (secondary track), making it possible to detect the rotation angle, rotation speed, rotation direction, etc. with high accuracy using only one sensor.

Patent No. 4587656

Therefore, it is expected that by combining a double-row track type rotation sensor with a bearing, it will be possible to realize a bearing device with an absolute type rotation sensor that has a small number of parts and is easy to assemble. However, no specific configuration has been proposed for combining a double-row track type rotation sensor with a bearing.

The object of the present invention is to provide a bearing device with an absolute type rotation sensor that can be simplified in configuration with fewer parts and is easy to assemble by combining a double-row track type rotation sensor with a bearing.

In order to achieve the above object, the present invention provides an absolute type rotation sensor type bearing device,
a bearing including a rotating raceway, a fixed raceway arranged opposite to the rotating raceway, and rolling elements interposed between the rotating raceway and the fixed raceway;
a ring-shaped detectable member fixed to the rotating race of the bearing, the detectable member having an annular core and a detectable portion having two rows of magnetic tracks provided around the circumferential direction of the core;
a rotation sensor unit fixed to the fixed race of the bearing, the rotation sensor unit including one rotation sensor that detects the rotation of the detection target part in a non-contact manner, a sensor board on which the rotation sensor is mounted, and a sensor housing that covers the sensor board and to which the sensor board is attached;
It is equipped with:

With this configuration, the detected part of the rotation sensor is a double-row track type, and the rotation sensor is mounted on the sensor board and then attached to the sensor housing, simplifying the configuration of the bearing device with fewer parts and facilitating assembly work.

In one embodiment of the present invention, the sensor housing may be formed with a mounting groove into which the sensor board is inserted and which positions the sensor board in the axial and radial directions. With this configuration, the rotation sensor and the part to be detected are positioned and a sensor gap is secured simply by inserting the sensor board into the mounting groove, so that a bearing device capable of highly accurate rotation detection can be assembled with simple operations.

In one embodiment of the present invention, the sensor board may be positioned using the end of the member to be detected as a reference. With this configuration, the rotation sensor can be easily positioned by using the end of the member to be detected as a reference.

In one embodiment of the present invention, the protrusion provided on the sensor housing may have a guide surface that can guide a member that is fitted onto the protrusion in a direction perpendicular to the axial direction. With this configuration, during the assembly process of the bearing device, the guide surface of the protrusion of the sensor housing can be used to easily and reliably press the member in a direction perpendicular to the axial direction. This makes it possible to position the sensor so that deviation in sensor position due to the influence of the gap between the rolling element and the raceway in the bearing is minimized. Therefore, a bearing device capable of highly accurate rotation detection can be assembled with simple operations.

In one embodiment of the present invention, the sensor housing may be configured so that the sensor board can be inserted into the mounting groove from the side opposite the bearing. With this configuration, the sensor board can be easily attached from the side opposite the bearing during the assembly process of the bearing device, making it possible to assemble a bearing device capable of highly accurate rotation detection with even simpler operations.

In one embodiment of the present invention, the storage section of the sensor housing that stores the sensor board may include a resin material filled in the space between the inner wall surface of the storage section and the sensor board, and a lid member that covers the end of the storage section opposite the bearing. With this configuration, the rotation sensor and the sensor board attached to the sensor housing can be securely fixed.

The shaft assembly according to one embodiment of the present invention is a bearing device mounted on an electric vertical take-off and landing aircraft that flies by rotating the rotors and includes a plurality of drive units each having a rotor and a motor that rotates the rotor, and may include a bearing that rotatably supports the rotation shaft of the drive unit. With this configuration, the above-mentioned advantages can be obtained even when the bearing device is applied to an electric vertical take-off and landing aircraft (a so-called flying car), which is expected to be an alternative means of transportation to automobiles.

As described above, the absolute type rotation sensor bearing device of the present invention combines a double-row track type rotation sensor with a bearing, making it possible to simplify the configuration with a small number of parts and to make the configuration easy to assemble.

1 is a vertical sectional view showing a schematic configuration of an absolute type rotation sensor type bearing device according to an embodiment of the present invention; 2 is a vertical sectional view showing a detection target member used in the bearing device of FIG. 1 . 2 is a plan view showing a detected member used in the bearing device of FIG. 1 . 2 is a front view showing a sensor unit used in the bearing device of FIG. 1. FIG. 2 is a cross-sectional view showing a schematic view of a radial internal gap of a bearing used in the bearing device of FIG. 1 . FIG. 2 is a cross-sectional view showing a schematic view of an axial internal gap of a bearing used in the bearing device of FIG. 1 . FIG. 2 is a cross-sectional view showing a schematic view of an axial internal gap of a bearing used in the bearing device of FIG. 1 . 2A to 2C are schematic diagrams showing an example of a method for assembling the bearing device of FIG. 1 . 7 is a front view showing a pressing member and a base used in the assembly method of FIG. 6 of FIG. 1. 2 is a schematic diagram showing an example of a method for aligning a sensor unit used in the bearing device of FIG. 1 . FIG. FIG. 11 is a vertical sectional view showing a schematic configuration of an absolute type rotation sensor type bearing device according to another embodiment of the present invention. 10A to 10C are schematic diagrams showing an example of a method for assembling the bearing device of FIG. 9 . 1 is a perspective view showing an electric vertical take-off and landing aircraft to which an absolute type rotation sensor type bearing device according to an embodiment of the present invention is applied. FIG. 12 is a vertical cross-sectional view showing a portion of a motor in a drive unit of the electric vertical take-off and landing aircraft of FIG.

The following describes an embodiment of the present invention with reference to the drawings, but the present invention is not limited to this embodiment.

Figure 1 shows an absolute type rotation sensor bearing device (hereinafter simply referred to as "bearing device") 1 according to one embodiment of the present invention. The bearing device 1 includes a bearing 3, an annular detection member 5 that is the subject of rotation detection, and a rotation sensor unit 7.

The bearing of this embodiment is configured as a ball bearing 3, and includes an inner ring 11, an outer ring 13 arranged to face the inner ring 11, and balls as rolling elements 15 interposed between the inner ring 11 and the outer ring 13. In this example, the bearing 3 is configured as an inner ring rotating type. That is, the inner ring 11 is configured as a rotating raceway ring, and the outer ring 13 is configured as a fixed raceway ring.

The detected member 5 is attached to the inner ring 11, which is a rotating raceway ring. As shown in FIG. 2, the detected member 5 has an annular core 17 and a detected portion 19 having two rows of magnetic tracks arranged around the circumferential direction of the core 17. More specifically, the core 17 has a cylindrical portion 17a and an attachment portion 17b having a smaller diameter than the cylindrical portion 17a, and the detected portion 19 is formed on the outer peripheral surface of the cylindrical portion 17a.

Specifically, in this embodiment, the detectable member 5 is formed by forming an annular unmagnetized magnetic member including a core 17, and then magnetizing the surface of this unmagnetized magnetic member with multiple rows (two rows in this example) of magnetic tracks with different numbers of magnetized pole pairs. The multiple rows of magnetic tracks become the detectable portion 19. The unmagnetized magnetic member is formed, for example, by placing a rubber material kneaded with magnetic powder on the outer peripheral surface of the core 17 made of a metal ring in a mold together with the core 17 and vulcanizing to bond them, or by integrally molding a mixture of plastic material and magnetic powder with the core 17. The core 17 is formed, for example, by press molding an iron-based rolled steel plate.

A detectable portion 19 is formed on the outer circumferential surface of the cylindrical portion 17a of the core metal 17. As shown in FIG. 3, the magnetization patterns of the two rows of magnetic tracks of the detectable portion 19 are made different, and the absolute angle of the rotating shaft can be detected by, for example, generating a difference between one pole pair per rotation. By using such double rows of magnetized tracks as the detectable member 5, highly accurate rotation detection is possible using only one rotation sensor.

As shown in FIG. 1, the rotation sensor unit 7 is attached to the outer ring 13, which is the fixed raceway of the bearing 3. The rotation sensor unit 7 has one rotation sensor 21 that detects the rotation of the detection target 19 in a non-contact manner, a sensor board 23 on which the rotation sensor 21 is mounted, and a sensor housing 25 that covers the sensor board 23 and to which the sensor board 23 is attached.

The rotation sensor 21 is mounted on the surface of the sensor board 23 facing inward in the radial direction of the bearing 3 so as to face the member to be detected 5. In the following description, the surface of the sensor board 23 on which the rotation sensor 21 is mounted is referred to as the front surface 23a, and the opposite surface is referred to as the back surface 23b. In this example, a magnetic sensor that generates an output signal corresponding to the magnetic flux density is used as the rotation sensor 21. A connector 27 is mounted on the back surface 23b of the sensor board 23, and a cable 29 is connected to the rotation sensor 21 via the connector 27 for outputting the signal of the rotation sensor 21 to the outside and for supplying power to the rotation sensor 21.

As shown in FIG. 4, the sensor housing 25 has an arc-shaped portion 31 arranged concentrically with the bearing 3 (FIG. 1), and a storage portion 33 having a shape that protrudes radially outward from the arc-shaped portion 31. The storage portion 33 is formed as a convex portion that protrudes from the arc-shaped portion 31. An attachment groove 35 is formed on the inner wall surface of the storage portion 33, into which the sensor board 23 is inserted and which positions the sensor board 23 in the axial and radial directions.

The outer side wall surface of the accommodation section 33 is formed as a guide surface 37 capable of guiding a member fitted to the accommodation section 33 in a direction perpendicular to the axial direction. More specifically, as shown in FIG. 4, the accommodation section 33 of the sensor housing 25 has a portion protruding from the arc-shaped portion 31 formed in an approximately rectangular shape, and has a top wall 33a covering the radial outside, a front wall 33b (FIG. 1) extending from one side of the end of the top wall 33a on one side (the bearing 3 side) in the axial direction in a direction perpendicular to the top wall 33a, and two side walls 33c extending from each side of both ends of the top wall 33a in a direction perpendicular to the top wall 33a. That is, the two side walls of the accommodation section 33 have outer side wall surfaces extending parallel to each other perpendicularly from each side of both ends of the front wall to the opposite side of the bearing 3. These two side wall surfaces function as guide surfaces 37 capable of guiding a member fitted to the accommodation section 33 in a direction perpendicular to the axial direction.

In addition, an attachment groove 35 extending parallel to the axial direction is formed on each inner wall surface of the two side walls 33c of the storage section 33. As shown in FIG. 1, the opening of the sensor housing 25 on the opposite side to the bearing 3, including the storage section 33, is formed separately from the sensor housing 25 and is covered by a lid member 39 that can be detachably attached to the sensor housing 25.

In this embodiment, the sensor housing 25 is attached to the outer ring 13, which is the fixed member of the bearing 3, via the outer ring member 41. Specifically, the outer ring member 41 has a cylindrical large diameter portion that fits onto the outer peripheral surface of the arc-shaped portion 31 of the sensor housing 25, and a cylindrical small diameter portion that fits onto the inner peripheral surface of the outer ring 13. On the other hand, the detected member 5 is attached to the inner ring 11, which is the rotating member of the bearing 3, via the annular adapter member 43. The adapter member 43 has a cylindrical small diameter portion that fits onto the inner peripheral surface of the mounting portion 17b of the core metal 17 of the detected member 5, and a cylindrical large diameter portion that fits onto the outer peripheral surface of the inner ring 11. The sensor housing 25 may be directly attached to the fixed member of the bearing 3 (the outer ring 13 in this example), and the detected member 5 may be directly attached to the rotating member of the bearing 3 (the inner ring 11 in this example).

By forming the accommodating portion 33 of the sensor housing 25 as described above, accurate positioning of the rotation sensor 21 and the detected portion 19 can be easily performed during the assembly process of the bearing device 1, which will be described later.

As shown in Figures 5A to 5C, in ball bearings 3, rolling elements 15 are generally assembled so that there is a radial internal gap δ and an axial internal gap δ1, δ2 between the inner ring 11 and the outer ring 13. The radial internal gap δ and the axial internal gap δ1, δ2 refer to the amount of movement when either the inner ring 11 or the outer ring 13 is fixed and the other is moved in the radial or axial direction. In general, the axial internal gaps δ1, δ2 are 8 to 10 times larger than the radial internal gap δ. By forming the axial internal gaps δ1, δ2, for example, when the outer ring 13 of the ball bearing 3 is fixed, the inner ring 11 can move in the axial direction by the same amount around the raceway groove bottoms of the inner ring 11 and the outer ring 13.

Therefore, when the bearing 3 is set so that the centers of the raceway grooves of the inner ring 11 and the outer ring 13 are aligned, and the rotation sensor 21 in FIG. 1 is attached to the sensor housing 25 fixed to the outer ring 13 side of the bearing 3, the amount of movement of the detected member 5 in the axial direction is within 4 to 5 times the radial internal gap δ, centered on the bottom of the raceway groove. However, if the centers of the raceway grooves of the inner ring 11 and the outer ring 13 of the bearing 3 are not set so that they are aligned, the rotation sensor 21 may be installed with the inner ring 11 biased in one direction in the axial direction. In this case, if the bearing 3 moves in the opposite direction, it may move in the axial direction a maximum distance of 8 to 10 times the radial internal gap δ. As a result, the center of the rotation sensor 21 and the center of the two rows of tracks of the detected part 19 are significantly misaligned, and the rotation sensor 21 may not be able to detect the rotation of the detected part 19.

To avoid such problems, the bearing device 1 of this embodiment is positioned in the axial direction during the assembly process by the method described below, as shown in Figure 6. In Figure 6, plan views are shown at the top of each step, and vertical cross-sectional views are shown at the bottom.

With the sensor housing 25 and the member to be detected 5 attached to the bearing 3, the inner ring 11 of the bearing 3 is fitted to the temporary shaft 47 for positioning, which is attached vertically to the base 45. At this time, the temporary shaft 47 is inserted so that the bearing 3 is positioned downward and the sensor housing 25 and the member to be detected 5 are positioned upward. A guide groove 49 is formed on the upper surface of the base 45, which extends along the radial direction of the bearing 3 and passes through the center of the storage section 33 of the sensor housing 25 in a plan view. A pressing member 51, which is approximately square overall, is installed on the base 45 at a position above the guide groove 49. As shown in FIG. 7, a guide protrusion 53 shaped to engage with the guide groove 49 is provided on the bottom surface of the pressing member 51, and the pressing member 51 is installed so that the guide protrusion 53 engages with the guide groove 49 (Step A).

In this state, as shown in FIG. 6, the upper part of the pressing member 51 faces the storage section 33 of the sensor housing 25. The upper part of the pressing member 51 is formed with a guide recess 55, which is a recess with a shape corresponding to the outer shape of the storage section 33 of the sensor housing 25. The pressing member 51 having such a structure is pressed on the guide groove 49 toward the center of the bearing 3 so that the guide recess 55 is aligned with the guide surface 37 of the storage section 33 (Step B). As a result, the flat pressing portion 57 formed below the guide recess 55 of the pressing member 51 is pressed against the outer peripheral surface of the outer ring 13 of the bearing 3, and the rolling element 15 abuts against the raceway groove bottoms 11a, 13a of the inner ring 11 and outer ring 13 of the bearing 3, so that the inner ring 11 and outer ring 13 of the bearing 3 are aligned based on the raceway groove bottoms 11a, 13a (Step C).

In this way, by providing the guide surface 37 capable of guiding the pressing member 51 in the accommodation portion 33 of the sensor housing 25, it is possible to easily and reliably perform the operation of pressing in a direction perpendicular to the axial direction using the guide surface 37. This makes it possible to position the sensor so that deviation in position due to the influence of the gap between the rolling elements 15 and the raceways 11 and 13 in the bearing 3 is minimized. Therefore, the bearing device 1 capable of highly accurate rotation detection can be assembled with simple operations.

Next, a method for positioning the rotation sensor 21 of the rotation sensor unit 7 in the axial direction relative to the bearing 3 and the detected member 5 positioned as described above will be described. In this example, the sensor board 23 is positioned based on the end of the detected member 5. Specifically, as shown in FIG. 2, the width dimensions of the two rows of tracks of the detected part 19 of the detected member 5 are set to the same L. Furthermore, as shown in FIG. 8, the width dimension of the sensor board 23 (axial dimension of the bearing 3) is set to 2L, which is the same as the width dimension of the entire detected part 19, and the sensor 21 is mounted so that the distance from the end face of the sensor board 23 to the center position M of the rotation sensor 21 is L, and the sensor board 23 is prepared. The sensor board 23 thus prepared is inserted into the mounting groove 35 of the sensor housing 25 attached to the bearing 3 in the positioned state shown in FIG. 6, and the positions of the end faces of the detected part 19 and the sensor board 23 on the opposite side of the bearing 3 are aligned. This allows the boundary line between the two rows of tracks of the annular detection target portion 19 to coincide with the center position M of the rotation sensor 21, using the raceway groove bottoms 11a and 13a of the bearing 3 as a reference. In particular, by using the end of the detection target member 5 as a reference, the rotation sensor 21 can be easily positioned.

In this embodiment, the inner axial dimension of the mounting groove 35 is set to the same length as the width dimension of the sensor board 23 from the end face of the housing portion 33 opposite the bearing 3. This makes it easy to position the detected portion 19 and the rotation sensor 21 by simply inserting the sensor board 23 into the mounting groove 35 and pushing it in to the end on the bearing 3 side.

The storage section 33 of the sensor housing 25 is configured so that the sensor board 23 can be inserted into the mounting groove 35 from the side opposite the bearing 3. Specifically, as shown in FIG. 1, the end of the sensor housing 25, including the storage section 33, opposite the bearing 3 is open, and the sensor housing 25 has a lid member 39 that is detachably attached to this end and covers the opening. Therefore, in the above positioning stage, by removing the lid member 39 of the sensor housing 25, it is possible to insert the sensor board 23 into the storage section 33 and the mounting groove 35 from the side opposite the bearing 3.

Next, a method for ensuring a radial gap ΔT between the rotation sensor 21 and the detected portion 19 (hereinafter referred to as the "sensor gap") will be described. As shown in Fig. 4, when the distance from the center of the sensor housing 25 to the bottom surface of the mounting groove 35 is T1, the radial dimension of the outer circumferential surface of the detected portion 19 of the detected member 5 is T2, and the distance from the surface 23a of the sensor board 23 after the sensor is mounted to the sensor surface (the surface facing the detected portion 19) is T3, the position of the mounting groove 35 and the dimensions of the rotation sensor 21 and the sensor board 23 are set in advance so as to satisfy the following formula:
ΔT=T1-T2-T3

As a result, once the axial positioning of the bearing 3 has been achieved using the method described above with reference to FIG. 6, the sensor gap ΔT can be maintained by simply inserting the sensor board 23 into the mounting groove 35 of the accommodating portion 33 of the sensor housing 25.

1, the storage section 33 has a resin material 61 filled in the space between the inner wall surface of the storage section 33 and the sensor board 23. The resin material 61 covers the rotation sensor 21 mounted on the sensor board 23 as well. As a method of filling the resin material 61, for example, the cable 29 is inserted into the connector 27, a resin material blocking plate (not shown) is inserted between the rotation sensor 21 and the member to be detected 5, and the inside of the storage section 33 of the sensor housing 25 is fixed with the resin material 61. In this case, a caulking agent may be applied to the connector 27 to prevent the resin material 61 from entering the inside of the connector 27. After removing the resin material blocking plate, a cover member 39 that covers the sensor housing 25 is attached. In this way, by filling the resin material 61, the rotation sensor 21 and the sensor board 23 attached to the sensor housing 25 can be reliably fixed.

In the above embodiment, an example in which the bearing 3 is configured as an inner ring rotating type has been described, but the present invention can also be applied to an outer ring rotating type bearing 3, as shown in another embodiment in Figure 9. In the following description, points common to the embodiment described in conjunction with Figures 1 to 9 will be omitted.

The bearing 3 according to this embodiment is configured as an outer ring rotating type. That is, the inner ring 11 is configured as a fixed side raceway ring, and the outer ring 13 is configured as a rotating side raceway ring. In this embodiment, the member to be detected 5 is attached to the outer ring 13, which is the rotating side raceway ring, and the rotation sensor unit 7 is attached to the inner ring 11, which is the fixed side raceway ring.

In this embodiment, the rotation sensor 21 is attached to the sensor housing 25 by inserting the sensor board 23 on which the rotation sensor 21 is mounted into the mounting groove 35 provided in the sensor housing 25.

The sensor housing 25 is provided with a guide portion 63 that is generally substantially rectangular and protrudes on the opposite side of the bearing 3 in the axial direction. The guide portion 63 is formed as a protrusion protruding from the sensor housing 25. The side of the guide portion 63 is formed as a guide surface 37 that can guide a member (a pressing member 51 shown in FIG. 10) that fits onto the guide portion 63 of the sensor housing 25 in a direction perpendicular to the axial direction. With this configuration, as shown in FIG. 10, it is possible to easily and reliably press the bearing 3 in a direction perpendicular to the axial direction using the guide surface 37. This makes it possible to position the sensor so that the deviation of the sensor position due to the influence of the gap between the rolling element 15 and the raceways 11 and 13 in the bearing 3 is minimized. Therefore, the bearing device 1 that can detect rotation with high accuracy can be assembled with simple operations.

According to the bearing device 1 with absolute type rotation sensor according to each embodiment described above, the detected portion 19 of the rotation sensor 21 is of a double-row track type, and the rotation sensor 21 is mounted on the sensor board 23 and attached to the sensor housing 25, which simplifies the configuration of the bearing device 1 with fewer parts and makes assembly easier.

Next, an application example of the bearing device 1 according to the embodiment described above will be described. The application of this bearing device 1 is not particularly limited, but it can be used, for example, in an electric vertical take-off and landing aircraft 71 shown in FIG. 11.

In recent years, flying cars, or vehicles that can fly, have been attracting attention as an alternative means of transportation to automobiles. Flying cars are expected to solve the above-mentioned social problems, and are expected to be used in a variety of situations, including local and inter-regional travel, tourism and leisure, emergency medical care, and disaster relief.

As a flying car, a vertical take-off and landing aircraft (VTOL) as shown in the figure has been attracting attention. A vertical take-off and landing aircraft can ascend and descend vertically between the sky and the take-off and landing site, so it does not require a runway and is highly convenient. In particular, in recent years, due to social demands for reducing _CO2 emissions, electric vertical take-off and landing aircraft 71 (eVTOL), which fly with batteries and motors, have become the mainstream of development.

The electric vertical take-off and landing aircraft 71 shown in FIG. 11 is a multicopter having a main body 73 located in the center of the aircraft, and four drive units 55 arranged in the front, back, left and right directions. The drive units 75 are devices that generate lift and thrust for the electric vertical take-off and landing aircraft 71, and the electric vertical take-off and landing aircraft 71 flies when driven by the drive units 75. The electric vertical take-off and landing aircraft 71 may have multiple drive units 75, and is not limited to four.

The main body 73 has a living space that can accommodate a crew member (for example, one or two people). This living space is provided with an operating system for determining the direction of travel and altitude, and instruments that indicate altitude, speed, flight position, etc. Four arms 77 extend from the main body 73, and a drive unit 75 is provided at the tip of each arm 77. In the example shown, a ring portion 81 that covers the rotating periphery of the rotor 79 is integrally provided to the arm 77 in order to protect the rotor 79. In addition, a skid 63 that supports the aircraft when it lands is provided below the main body 73.

The drive unit 75 has a rotor 79 and a motor 85 that rotates the rotor 79. In the drive unit 75, a pair of rotors 79 are provided on both axial sides of the motor 85. Each rotor 79 has two blades that extend radially outward.

The main body 73 is provided with a battery (not shown) and a control device (not shown). The control device is also called a flight controller. The electric vertical take-off and landing aircraft 71 is controlled by the control device, for example, as follows. The control device outputs a command to change the rotation speed of the motor 85, which should adjust the lift based on the difference between the current attitude and the target attitude. Based on the command, the inverter provided in the motor 85 adjusts the amount of power sent from the battery to the motor 85, and the rotation speed of the motor 85 (and the rotor 79) is changed. Furthermore, the adjustment of the rotation speed of the motor 85 is performed simultaneously for multiple motors 85, and the attitude of the aircraft is determined thereby.

Figure 12 shows a partial cross-sectional view of the motor 85 in the drive unit 75. The above-mentioned rotor 79 is attached to one end (upper side of the figure) of the rotating shaft 87 of the motor 85, and a rotor is attached to the other end (lower side of the figure). The rotor is disposed opposite a stator fixed to a housing 89 and is rotatable relative to the stator. The motor 85 can be configured as an outer rotor type brushless motor 85 or an inner rotor type brushless motor 85.

The motor 85 includes a housing (device housing) 89, a rotor (not shown), a stator (not shown), an inverter (not shown), and two bearings 3. In this example, the bearings 3 are inner ring rotating type rolling bearings 3 (more specifically, deep groove ball bearings).

The housing 89 has an outer cylinder 89a and an inner cylinder 89b, and a cooling medium flow path 69c is provided between them. By flowing a cooling medium through this cooling medium flow path 89c, excessive temperature rise can be prevented. There are no particular limitations on the material of the housing 89, and for example, iron-based materials or CFRP (carbon fiber reinforced plastic) can be used.

The bearing 3 rotatably supports the rotating shaft 87 within the housing 89. In FIG. 2, the outer diameter shape of the outer ring 13 of the bearing 3 is the same as the shape of the fitting portion on the inner circumference of the housing 89, and the bearing 3 is directly fitted into the housing 89 without going through a housing or the like. An inner ring spacer 91 and an outer ring spacer 93 are inserted between the two bearings 3, and a preload is applied.

The bearing 3 configuration in the drive unit 75 is not limited to the example in FIG. 12. In FIG. 12, an example is shown in which the rotating shaft 87 of the motor 85 and the rotating shaft of the rotor 79 are the same rotating shaft 87, but the rotating shaft 87 of the motor 85 and the rotating shaft of the rotor 79 may be connected via a transmission mechanism. In this case, the bearing 3 supporting the rotating shaft 87 in the drive unit 75 may be the bearing 3 supporting the rotating shaft 87 of the motor 85, or may be the bearing 3 supporting the rotating shaft of the rotor 79.

In this embodiment, the bearing device 1 is provided with a detection member 5 having the configuration described above and a rotation sensor unit 7 attached to the bearing 3, allowing for highly accurate rotation detection.

In this embodiment, the bearing 3 is not limited to the deep groove ball bearing shown as an example, and an angular contact ball bearing may also be used, for example.

As described above, a preferred embodiment of the present invention has been described with reference to the drawings, but various additions, modifications, and deletions are possible without departing from the spirit of the present invention. Therefore, such additions, modifications, and deletions are also included within the scope of the present invention.

1 Absolute type rotation sensor bearing device 3 Bearing 5 Detected member 7 Sensor unit 9 Electrical connection means 11 Inner ring (rotating raceway ring)
13 Outer ring (fixed raceway ring)
15 rolling element 17 core metal 19 detected part 21 rotation sensor 23 sensor board 25 sensor housing 35 mounting groove 37 guide surface 61 resin material 71 electric vertical take-off and landing aircraft

Claims (9)

a bearing including a rotating raceway, a fixed raceway arranged opposite to the rotating raceway, and rolling elements interposed between the rotating raceway and the fixed raceway;
a ring-shaped detectable member fixed to the rotating race of the bearing, the detectable member having an annular core and a detectable portion having two rows of magnetic tracks provided around the circumferential direction of the core;
a rotation sensor unit fixed to the fixed race of the bearing, the rotation sensor unit including one rotation sensor that detects the rotation of the detection target part in a non-contact manner, a sensor board on which the rotation sensor is mounted, and a sensor housing that covers the sensor board and to which the sensor board is attached;
An absolute type rotation sensor-equipped bearing device comprising:
an accommodation portion of the sensor housing that accommodates the sensor board includes a resin material filled in a space between an inner wall surface of the accommodation portion and the sensor board; and a cover member that covers an end portion of the accommodation portion opposite the bearing and is detachably attached to an end portion of the sensor housing.
A bearing device with an absolute type rotation sensor comprising: 2. The bearing device with an absolute type rotation sensor according to claim 1, wherein the sensor housing has a mounting groove into which the sensor board is inserted and which positions the sensor board in the axial and radial directions. 3. The bearing device with an absolute type rotation sensor according to claim 1, wherein the sensor board is positioned with reference to an end of the member to be detected. 4. The bearing device with an absolute type rotation sensor according to claim 1, wherein a convex portion provided on the sensor housing has a guide surface capable of guiding a member fitted onto the convex portion in a direction perpendicular to the axial direction. 5. The bearing device with an absolute type rotation sensor according to claim 1, wherein the sensor housing is configured so that the sensor board can be inserted into the mounting groove from the side opposite to the bearing. The bearing device with absolute type rotation sensor according to any one of claims 1 to 5,
A bearing device mounted on an electric vertical take-off and landing aircraft that flies by rotation of a rotor and a plurality of drive units each having a motor that rotates the rotor, the bearing device comprising:
The bearing device with absolute type rotation sensor includes a bearing that rotatably supports a rotation shaft of the drive unit. 7. The bearing device with absolute type rotation sensor according to claim 1 ,
The bearing device with an absolute type rotation sensor, wherein the rotation sensor is attached to the sensor housing with the centers of the raceway grooves of the rotating race and the fixed race aligned. 8. The bearing device with an absolute type rotation sensor according to claim 7, wherein the amount of axial movement of the detected portion is less than five times the radial internal gap centered on the groove bottom of each of the raceways. a bearing including a rotating raceway, a fixed raceway arranged opposite to the rotating raceway, and rolling elements interposed between the rotating raceway and the fixed raceway;
a ring-shaped detectable member fixed to the rotating race of the bearing, the detectable member having an annular core and a detectable portion having two rows of magnetic tracks provided around the circumferential direction of the core;
a rotation sensor unit fixed to the fixed race of the bearing, the rotation sensor unit including one rotation sensor that detects the rotation of the detection target part in a non-contact manner, a sensor board on which the rotation sensor is mounted, and a sensor housing that covers the sensor board and to which the sensor board is attached;
A sensor positioning method for an absolute type rotation sensor-equipped bearing device comprising:
a rotation sensor positioning method for mounting the rotation sensor on the sensor housing in a state in which the centers of the raceway grooves of the rotating race and the fixed race coincide with the centers of the rolling elements;

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