Bearing device with absolute type rotation sensor

Abstract

To provide a bearing device with an absolute-type rotation sensor which can simplify a constitution by a small number of part items by combining a double-row track-type rotation sensor to a bearing, and is easy in assembling.SOLUTION: In a bearing device (1) with an absolute-type rotation sensor comprising a bearing (3) and a detected member (5) fixed to a rotation-side bearing ring of the bearing (3), and having a detected part (19) having a double-row magnetic track arranged over a peripheral direction of an annular core grid (17), there is arranged a rotation sensor unit (7) having one rotation sensor (21) fixed to a fixed-side bearing ring of the bearing (3), and detecting the rotation of the detected part (19) at a non-contact manner, a sensor baseboard (23) on which the rotation sensor (21) is mounted, and a sensor housing (25) for covering the sensor baseboard (23), and attached with the sensor baseboard (23).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bearing device provided with an absolute type rotation sensor.

Background Art

[0002] As a bearing for rotatably supporting joints and the like of industrial robots, a bearing device provided with an absolute type rotation sensor capable of high-precision control is used. As a bearing device with an absolute type rotation sensor, for example, one having one origin detection unit and two absolute angle detection units has been proposed (see, for example, Patent Document 1).

[0003] In this bearing device, a total of three sensors and cables connected to these sensors are required, resulting in a large number of parts. In addition, since the two absolute angle detection units need to be positioned so as to have a phase difference of about 90° from each other, the assembly work becomes complicated.

[0004] Therefore, as an absolute type rotation sensor to be combined with a bearing, it is conceivable to use a multi-track type rotation sensor. This multi-track type rotation sensor is provided with two magnetic tracks, a magnetic track for angle detection (main track) and a magnetic track for phase difference detection (sub track), on the circumferential surface of an annular core metal, so that a single sensor can detect the rotation angle, rotation speed, rotation direction, etc. with high precision.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, by combining a multi-row track type rotation sensor with a bearing, it is expected that an absolute type rotation sensor-equipped bearing device with a small number of parts and easy assembly can be realized. However, no specific configuration has been proposed for the case of combining a multi-row track type rotation sensor with a bearing.

[0007] Therefore, an object of the present invention is to provide an absolute type rotation sensor-equipped bearing device that can simplify the configuration with a small number of parts and is easy to assemble by combining a multi-row track type rotation sensor with a bearing.

Means for Solving the Problems

[0008] To achieve the above object, the absolute type rotation sensor-equipped bearing device according to the present invention includes a bearing having a rotating-side raceway ring, a fixed-side raceway ring arranged to face the rotating-side raceway ring, and rolling elements interposed between the rotating-side raceway ring and the fixed-side raceway ring, an annular detected member fixed to the rotating-side raceway ring of the bearing, the detected member having an annular core metal and a detected portion having two rows of magnetic tracks provided in the circumferential direction of the core metal, a rotation sensor unit fixed to the fixed-side raceway ring of the bearing, the rotation sensor unit having one rotation sensor for non-contact detection of the rotation of the detected portion, a sensor substrate on which the rotation sensor is mounted, and a sensor housing covering the sensor substrate and to which the sensor substrate is attached, and is provided with.

[0009] According to this configuration, since the detected portion of the rotation sensor is of a multi-row track type and the rotation sensor is attached to the sensor housing in a state of being mounted on the sensor substrate, the configuration of the bearing device is simplified with a small number of parts, and the assembly work becomes easy.

[0010] In one embodiment of the present invention, a mounting groove may be formed in the sensor housing into which the sensor substrate is inserted and which positions the sensor substrate in the axial direction and the radial direction. According to this configuration, the rotation sensor and the detected portion can be positioned and the sensor gap can be secured simply by inserting the sensor substrate into the mounting groove, so that a bearing device capable of highly accurate rotation detection can be assembled by simple work.

[0011] In one embodiment of the present invention, the sensor substrate may be positioned with reference to the end portion of the detected member. According to this configuration, the rotation sensor can be simply positioned by using the end portion of the detected member as a reference.

[0012] In one embodiment of the present invention, the convex portion provided on the sensor housing may have a guide surface that can guide a member that fits over the convex portion in a direction orthogonal to the axial direction. According to this configuration, in the assembly process of the bearing device, it becomes possible to easily and surely perform the operation of pressing in the direction orthogonal to the axial direction by using the guide surface of the convex portion of the sensor housing. As a result, it becomes possible to perform positioning such that the displacement of the sensor position due to the influence of the gap between the rolling elements and the raceway rings in the bearing is minimized. Therefore, a bearing device capable of highly accurate rotation detection can be assembled by simple work.

[0013] In one embodiment of the present invention, the sensor housing may be configured to be able to insert the sensor substrate into the mounting groove from the side opposite to the bearing. According to this configuration, in the assembly process of the bearing device, the sensor substrate can be easily attached from the side opposite to the bearing, so that a bearing device capable of highly accurate rotation detection can be assembled by even simpler work.

[0014] In one embodiment of the present invention, the housing portion that houses the sensor substrate of the sensor housing may include a resin material filled in the space between the inner wall surface of the housing portion and the sensor substrate, and a lid member that covers an end portion of the housing portion opposite to the bearing. According to this configuration, the rotary sensor and the sensor substrate attached to the sensor housing can be securely fixed.

[0015] A bearing device according to an embodiment of the present invention is a bearing device mounted on an electric vertical takeoff and landing aircraft that has a plurality of drive units each having a rotary blade and a motor that rotates the rotary blade, and flies by the rotation of the rotary blade, and may include a bearing that rotatably supports the rotation shaft of the drive unit. According to this configuration, even when the bearing device is applied to an electric vertical takeoff and landing aircraft (so-called flying car) expected as a means of transportation instead of an automobile, the above-described advantages can be obtained.

Advantages of the Invention

[0016] As described above, according to the absolute rotary sensor type bearing device according to the present invention, by combining a multi-row track type rotary sensor with a bearing, the configuration can be simplified with a small number of parts, and an easy-to-assemble configuration can be achieved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

[0019] FIG. 1 shows an absolute rotation sensor type bearing device (hereinafter simply referred to as “bearing device”) 1 according to an embodiment of the present invention. The bearing device 1 includes a bearing 3, an annular detected member 5 that is an object of rotation detection, and a rotation sensor unit 7.

[0020] The bearing of this embodiment is configured as a ball bearing 3, and includes an inner ring 11, an outer ring 13 disposed to face the inner ring 11, and balls 15 as rolling elements interposed between the inner ring 11 and the outer ring 13. In this example, the bearing 3 is configured as an inner ring rotation type. That is, the inner ring 11 is configured as a rotating side raceway ring, and the outer ring 13 is configured as a fixed side raceway ring.

[0021] The detected member 5 is attached to the inner ring 11 which is a rotating side raceway ring. As shown in FIG. 2, the detected member 5 has an annular core metal 17 and a detected part 19 having two rows of magnetic tracks provided in the circumferential direction of the core metal 17. More specifically, the core metal 17 has a cylindrical part 17a and a mounting part 17b having a smaller diameter than the cylindrical part 17a, and the detected part 19 is formed on the outer peripheral surface of the cylindrical part 17a.

[0022] Specifically, the detected member 5 of this embodiment is formed by forming an annular non-magnetized magnetic member including the core metal 17, and then magnetizing two rows (two rows in this example) of magnetic tracks having different numbers of magnetization pole pairs on the surface of this non-magnetized magnetic member. The two rows of magnetic tracks become the detected part 19. The non-magnetized magnetic member is formed, for example, by kneading magnetic powder with a rubber material on the outer peripheral surface of the core metal 17 made of a metal ring, putting it into a mold together with the core metal 17 and vulcanizing and adhering it, or integrally molding a mixture of a plastic material and magnetic powder with the core metal 17. The core metal 17 is formed, for example, by press-forming an iron-based rolled steel sheet.

[0023] The detected part 19 is formed on the outer peripheral surface of the cylindrical part 17a of the core metal 17. As shown in FIG. 3, by making the magnetization patterns of the two rows of magnetic tracks of the detected part 19 different, for example, generating a difference of one pole pair per rotation, it is possible to detect the absolute angle of the rotating shaft. By using such a two-row magnetized track as the detected member 5, high-precision rotation detection can be achieved with only one rotation sensor.

[0024] As shown in Fig. 1, the rotation sensor unit 7 is attached to the outer ring 13 which is the fixed-side race of the bearing 3. The rotation sensor unit 7 includes a rotation sensor 21 that non-contactly detects the rotation of the detected part 19, a sensor substrate 23 on which the rotation sensor 21 is mounted, and a sensor housing 25 that covers the sensor substrate 23 and to which the sensor substrate 23 is attached.

[0025] The rotation sensor 21 is mounted on the surface of the sensor substrate 23 facing the inner side in the radial direction of the bearing 3 so as to face the detected member 5. In the following description, the surface of the sensor substrate 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 substrate 23, and a cable 29 for outputting the signal of the rotation sensor 21 to the outside and supplying power to the rotation sensor 21 is connected to the rotation sensor 21 via the connector 27.

[0026] 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 housing portion 33 having a shape protruding radially outward from the arc-shaped portion 31. The housing portion 33 is formed as a convex portion protruding from the arc-shaped portion 31. An attachment groove 35 for inserting the sensor substrate 23 and positioning the sensor substrate 23 in the axial direction and the radial direction is formed on the inner wall surface of the housing portion 33.

[0027] The outer side wall surface of the housing portion 33 is formed as a guide surface 37 capable of guiding a member externally fitted to the housing portion 33 in a direction orthogonal to the axial direction. More specifically, as shown in FIG. 4, the housing portion 33 of the sensor housing 25 has a portion protruding from the arcuate portion 31 formed in a substantially square shape, a top wall 33a covering the radially outer side, a front wall 33b (FIG. 1) extending in a direction orthogonal to the top wall 33a from one side of the end portion of the top wall 33a on one side in the axial direction (bearing 3 side), and two side walls 33c extending in a direction orthogonal to the top wall 33a from each side of both end portions of the top wall 33a. That is, the two side walls of the housing portion 33 have outer side wall surfaces that extend perpendicularly to the opposite side of the bearing 3 from each side of both end portions of the front wall and are parallel to each other. These two side wall surfaces function as a guide surface 37 capable of guiding a member externally fitted to the housing portion 33 in a direction orthogonal to the axial direction.

[0028] Further, mounting grooves 35 extending parallel to the axial direction are formed on the inner wall surfaces of the two side walls 33c of the housing portion 33. As shown in FIG. 1, the opening on the side opposite to the bearing 3 of the sensor housing 25 is formed separately from the sensor housing 25 including the housing portion 33 and is covered by a lid member 39 detachably attached to the sensor housing 25.

[0029] In the present embodiment, the sensor housing 25 is attached to the outer ring 13 which is a fixed-side member of the bearing 3 via an outer ring member 41. Specifically, the outer ring member 41 has a cylindrical large-diameter portion fitted to the outer peripheral surface of the arcuate portion 31 of the sensor housing 25 and a cylindrical small-diameter portion fitted to 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 a rotating-side member of the bearing 3 via an annular adapter member 43. The adapter member 43 has a cylindrical small-diameter portion fitted to the inner peripheral surface of the attachment portion 17b of the core metal 17 of the detected member 5 and a cylindrical large-diameter portion fitted to the outer peripheral surface of the inner ring 11. Note that the sensor housing 25 may be directly attached to the fixed-side member of the bearing 3 (the outer ring 13 in this example), and the detected member 5 may be directly attached to the rotating-side member of the bearing 3 (the inner ring 11 in this example).

[0030] Since the housing portion 33 of the sensor housing 25 is formed as described above, in the assembling process of the bearing device 1 to be described later, the accurate positioning work of the rotation sensor 21 and the detected portion 19 becomes easy.

[0031] As shown in FIGS. 5A to 5C, in the ball bearing 3, generally, the rolling elements 15 are incorporated such that there are a radial internal clearance δ and axial internal clearances δ1, δ2 between the inner ring 11 and the outer ring 13. Note that the radial internal clearance δ and the axial internal clearances δ1, δ2 are the amounts of movement when either the inner ring 11 or the outer ring 13 is fixed and the other is moved in the radial direction or the axial direction. Generally, the axial internal clearances δ1, δ2 are 8 to 10 times the size of the radial internal clearance δ. Due to the formation of the axial internal clearances δ1, δ2, for example, when the outer ring 13 of the ball bearing 3 is fixed, the inner ring 11 can move by the same dimension in the axial direction around the bottom of the raceway groove of the inner ring 11 and the outer ring 13.

[0032] Therefore, when the bearing 3 is attached to the sensor housing 25 with the rotation sensor 21 of FIG. 1 fixed to the outer ring 13 side of the bearing 3 in a state where the centers of the respective raceway grooves of the inner ring 11 and the outer ring 13 are aligned, the amount of movement of the detected member 5 in the axial direction is within 4 to 5 times the radial internal clearance δ around the bottom of the raceway groove. However, when the centers of the respective raceway grooves of the inner ring 11 and the outer ring 13 of the bearing 3 are not aligned, the rotation sensor 21 may be incorporated in a state where the inner ring 11 is biased in one direction in the axial direction. In this case, when the bearing 3 moves in the opposite direction, there is a possibility that it may move in the axial direction by a distance up to 8 to 10 times the radial internal clearance δ at most. As a result, the position of the center of the rotation sensor 21 and the center of the two rows of tracks of the detected portion 19 may deviate significantly, and there may be a case where the rotation sensor 21 cannot detect the rotation of the detected portion 19.

[0033] To avoid such problems, in the assembly process, as shown in FIG. 6, the bearing device 1 of the present embodiment performs positioning in the axial direction by the method described below. In FIG. 6, a plan view is shown above each step, and a longitudinal sectional view is shown below each step.

[0034] With the sensor housing 25 and the detected member 5 assembled to the bearing 3, the inner ring 11 of the bearing 3 is fitted onto a positioning temporary shaft 47 vertically attached to the pedestal 45. At this time, the bearing 3 is inserted into the temporary shaft 47 so that the bearing 3 is positioned downward and the sensor housing 25 and the detected member 5 are positioned upward. On the upper surface of the pedestal 45, a guide groove 49 extending along the radial direction of the bearing 3 passing through the center of the housing portion 33 of the sensor housing 25 in plan view is formed. An approximately square pressing member 51 is installed at a position on the guide groove 49 of the pedestal 45. As shown in FIG. 7, a guide convex portion 53 having a shape engaging 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 convex portion 53 engages with the guide groove 49 (Step A).

[0035] In this state, as shown in FIG. 6, the upper portion of the pressing member 51 faces the housing portion 33 of the sensor housing 25. A guide concave portion 55, which is a concave portion having a shape corresponding to the outer shape of the housing portion 33 of the sensor housing 25, is formed in the upper portion of the pressing member 51. The pressing member 51 having such a structure is pushed along the guide groove 49 toward the center of the bearing 3 so that the guide concave portion 55 follows the guide surface 37 of the housing portion 33 (Step B). As a result, a flat pressing portion 57 formed below the guide concave portion 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 elements 15 come into contact with the bottom surfaces 11a, 13a of the raceway grooves of the inner ring 11 and the outer ring 13 of the bearing 3, so that the inner ring 11 and the outer ring 13 of the bearing 3 are aligned with reference to the bottom surfaces 11a, 13a of the raceway grooves (Step C).

[0036] In this way, by providing the guide surface 37 capable of guiding the pressing member 51 in the accommodating portion 33 of the sensor housing 25, it becomes possible to easily and surely perform the operation of pressing in the direction orthogonal to the axial direction by utilizing the guide surface 37. As a result, it becomes possible to perform positioning such that the displacement of the sensor position due to the influence of the gap between the rolling elements 15 and the raceway rings 11, 13 in the bearing 3 is minimized. Therefore, the bearing device 1 capable of highly accurate rotation detection can be assembled by a simple operation.

[0037] Next, a method for positioning the rotation sensor 21 of the rotation sensor unit 7 in the axial direction with respect to the bearing 3 and the detected member 5 positioned as described above will be described. In this example, the sensor substrate 23 is positioned with reference to the end portion of the detected member 5. Specifically, as shown in FIG. 2, the width dimensions of each of the two rows of tracks of the detected portion 19 of the detected member 5 are set to the same L. Further, as shown in FIG. 8, after setting the width dimension (axial center dimension of the bearing 3) of the sensor substrate 23 to 2L, which is the same as the width dimension of the entire detected portion 19, the sensor 21 is mounted so that the distance from the end surface of the sensor substrate 23 at the center position M of the rotation sensor 21 becomes L, and the sensor substrate 23 is prepared. The sensor substrate 23 thus manufactured is inserted into the mounting groove 35 of the sensor housing 25 attached to the positioned bearing 3 shown in FIG. 6, and the positions of the end surfaces on the opposite side of the bearing 3 of the detected portion 19 and the sensor substrate 23 are made to coincide. As a result, with reference to the bottom surfaces 11a, 13a of the raceway grooves of the bearing 3, the boundary line between the two rows of tracks of the annular detected portion 19 and the center position M of the rotation sensor 21 can be made to coincide. In particular, by using the end portion of the detected member 5 as a reference, the positioning of the rotation sensor 21 can be easily performed.

[0038] Note that, in the present embodiment, the inner dimension in the axial direction of the mounting groove 35 is set to the same length as the width dimension of the sensor substrate 23 from the end surface on the opposite side of the bearing 3 in the accommodating portion 33. As a result, simply by inserting the sensor substrate 23 into the mounting groove 35 and pushing it to the end on the bearing 3 side, the positioning of the detected portion 19 and the rotation sensor 21 can be easily performed.

[0039] In addition, the accommodation portion 33 of the sensor housing 25 is configured such that the sensor substrate 23 can be inserted into the mounting groove 35 from the side opposite to the bearing 3. Specifically, as shown in FIG. 1, the end portion of the sensor housing 25 on the side opposite to the bearing 3 including the accommodation portion 33 is open, and the sensor housing 25 has a lid member 39 that is detachably attached to this end portion and covers the opening. Therefore, in the above positioning step, by removing the lid member 39 of the sensor housing 25, it is possible to insert the sensor substrate 23 into the mounting groove 35 from the side opposite to the bearing 3 into the accommodation portion 33.

[0040] Next, a method for ensuring the radial gap (hereinafter referred to as "sensor gap") ΔT between the rotary sensor 21 and the detected portion 19 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 radius dimension of the outer peripheral surface of the detected portion 19 of the detected member 5 is T2, and the distance from the surface 23a of the sensor substrate 23 after sensor mounting to the sensor surface (the surface facing the detected portion 19) is T3, the position of the mounting groove 35, the dimensions of the rotary sensor 21, and the sensor substrate 23 are preset so as to satisfy the following formula. ΔT = T1 - T2 - T3

[0041] Thereby, in a state where the positioning in the axial center direction on the bearing 3 side is performed by the method described with reference to FIG. 6, it becomes possible to maintain the sensor gap ΔT simply by inserting the sensor substrate 23 into the mounting groove 35 of the accommodation portion 33 of the sensor housing 25.

[0042] Also, as shown in FIG. 1, the housing portion 33 has a resin material 61 filled in the space between the inner wall surface of the housing portion 33 and the sensor substrate 23. The resin material 61 covers the rotation sensor 21 mounted on the sensor substrate 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 detected member 5, and the inside of the housing portion 33 of the sensor housing 25 is fixed with the resin material 61. In that case, in order to prevent the resin material 61 from entering the connector 27, a caulking agent may be applied to the connector 27. After removing the resin material blocking plate, the lid member 39 that covers the sensor housing 25 is attached. Thus, by filling the resin material 61, the rotation sensor 21 and the sensor substrate 23 attached to the sensor housing 25 can be securely fixed.

[0043] In the above-described embodiment, an example in which the bearing 3 is configured as an inner ring rotation type has been described. However, as shown in FIG. 9 as another embodiment, the present invention can also be applied even if the bearing 3 is an outer ring rotation type. In the following description, the description of the points common to the embodiment described with FIGS. 1 to 9 will be omitted.

[0044] The bearing 3 according to the present embodiment is configured as an outer ring rotation 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. Also, in the present embodiment, the detected member 5 is attached to the outer ring 13 that is the rotating-side raceway ring, and the rotation sensor unit 7 is attached to the inner ring 11 that is the fixed-side raceway ring.

[0045] Also in the present embodiment, the sensor substrate 23 on which the rotation sensor 21 is mounted is inserted into the mounting groove 35 provided in the sensor housing 25, whereby the rotation sensor 21 is attached to the sensor housing 25.

[0046] Further, the sensor housing 25 is provided with a generally rectangular guide portion 63 that protrudes as a whole on the side opposite to the bearing 3 in the axial direction. The guide portion 63 is formed as a convex portion protruding from the sensor housing 25. The side surface of the guide portion 63 is formed as a guide surface 37 that can guide a member (the pressing member 51 shown in FIG. 10) that fits over the guide portion 63 of the sensor housing 25 in a direction orthogonal to the axial direction. With such a configuration, as shown in FIG. 10, by using the guide surface 37, it becomes possible to easily and surely perform the operation of pressing the bearing 3 in a direction orthogonal to the axial direction. As a result, it becomes possible to perform positioning such that the displacement of the sensor 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 a simple operation.

[0047] According to the bearing device 1 with an absolute type rotation sensor according to each of the embodiments described above, the detected portion 19 of the rotation sensor 21 is of a double-row track type, and by attaching the rotation sensor 21 to the sensor housing 25 in a state where it is mounted on the sensor substrate 23, the configuration of the bearing device 1 is simplified with a small number of parts, and the assembly work becomes easy.

[0048] Next, an application example of the bearing device 1 according to the embodiment described above will be described. The use of this bearing device 1 is not particularly limited, but for example, it can be used in an electric vertical takeoff and landing aircraft 71 shown in FIG. 11.

[0049] In recent years, so-called flying cars, which are automobiles capable of flying as a means of transportation replacing automobiles, have attracted attention. Flying cars are expected to solve the above social problems and are expected to be used in various scenarios such as intra-regional movement, inter-regional movement, tourism and leisure, emergency medical care, and disaster relief.

[0050] As a flying car, a vertical take-off and landing aircraft (VTOL) as shown in the figure has attracted attention. Since a vertical take-off and landing aircraft can vertically take off and land from the ground and the airfield, it does not require a runway and is excellent in convenience. In particular, in recent years, due to social demands for CO2 reduction, etc., an electric vertical take-off and landing aircraft 71 (eVTOL) that flies with a battery and a motor has become the mainstream of development.

[0051] The electric vertical take-off and landing aircraft 71 shown in Fig. 11 is a multicopter having a main body 73 located at the center of the fuselage and four drive units 55 arranged in the front, rear, left, and right. The drive unit 75 is a device that generates lift and propulsion force for the electric vertical take-off and landing aircraft 71, and the electric vertical take-off and landing aircraft 71 flies by driving the drive unit 75. In the electric vertical take-off and landing aircraft 71, there may be a plurality of drive units 75, and it is not limited to four.

[0052] The main body 73 has a living space where passengers (for example, about 1 to 2 people) can board. This living space is provided with an operating system for determining the traveling direction, altitude, etc., and instruments for indicating altitude, speed, flight position, etc. Four arms 77 extend from the main body 73, and drive units 75 are provided at the tips of the respective arms 77. In the illustrated example, the arm 77 is integrally provided with an annular portion 81 that covers the rotation circumference of the rotary wing 79 in order to protect the rotary wing 79. In addition, a skid 63 for supporting the fuselage during landing is provided at the lower part of the main body 73.

[0053] The drive unit 75 has a rotary wing 79 and a motor 85 for rotating the rotary wing 79. In the drive unit 75, a pair of rotary wings 79 are provided on both axial sides with the motor 85 interposed therebetween. Each rotary wing 79 has two blades extending radially outward.

[0054] 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 control of the electric vertical takeoff and landing aircraft 71 is carried out by the control device as follows, for example. The control device outputs a command to change the rotation speed to the motor 85 whose lift force should be adjusted 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 electric power sent from the battery to the motor 85, and the rotation speed of the motor 85 (and the rotary wing 79) is changed. In addition, the adjustment of the rotation speed of the motor 85 is carried out simultaneously for a plurality of motors 85, thereby determining the attitude of the aircraft.

[0055] FIG. 12 shows a partial cross-sectional view of the motor 85 in the drive unit 75. The above-described rotary wing 79 is attached to one end side (the upper side in the figure) of the rotation shaft 87 of the motor 85, and a rotor is attached to the other end side (the lower side in the figure). The rotor is disposed opposite to the stator fixed to the housing 89 and is rotatable with respect to the stator. Note that the motor 85 can adopt the configuration of an outer rotor type brushless motor 85 or an inner rotor type brushless motor 85.

[0056] 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, as the bearing 3, a rolling bearing 3 of the inner ring rotation type (more specifically, a deep groove ball bearing) is used.

[0057] The housing 89 has an outer cylinder 89a and an inner cylinder 89b, and a cooling medium flow path 69c is provided therebetween. By flowing a cooling medium through this cooling medium flow path 89c, an excessive temperature rise can be prevented. The material of the housing 89 is not particularly limited, and for example, an iron-based material or CFRP (carbon fiber reinforced plastic) can be used.

[0058] 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 to the housing 89 without passing through a bearing housing or the like. An inner ring spacer 91 and an outer ring spacer 93 are inserted between the two bearings 3, and preload is applied.

[0059] Note that 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 where the rotating shaft 87 of the motor 85 and the rotating shaft of the rotating blade 79 are the same rotating shaft 87, but a configuration where the rotating shaft 87 of the motor 85 and the rotating shaft of the rotating blade 79 are connected via a transmission mechanism may also be used. In this case, the bearing 3 that supports the rotating shaft 87 in the drive unit 75 may be the bearing 3 that supports the rotating shaft 87 of the motor 85, or may be the bearing 3 that supports the rotating shaft of the rotating blade 79.

[0060] Also in this embodiment, a bearing device 1 is provided in which a detected member 5 having the configuration described above and a rotation sensor unit 7 are attached to the bearing 3, and highly accurate rotation detection can be performed.

[0061] Note that also in this embodiment, the bearing 3 is not limited to the illustrated deep groove ball bearing, and for example, an angular ball bearing may be used.

[0062] As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, changes, or deletions are possible without departing from the spirit of the present invention. Therefore, such things are also included within the scope of the present invention.

Explanation of Reference Numerals

[0063] 1 Absolute type rotation sensor type bearing device 3 Bearing 5 Detected member 7 Sensor unit 9 Electrical connection means 11 Inner ring (rotating side raceway ring) 13 Outer ring (fixed side raceway ring) 15 Rolling element 17 - core gold 19 - detected part 21 - rotation sensor 23 - sensor substrate 25 - sensor housing 35 - mounting groove 37 - guide surface 61 - resin material 71 - electric vertical take - off and landing aircraft

Claims

1. A bearing having a rotating-side raceway ring, a fixed-side raceway ring arranged to face the rotating-side raceway ring, and rolling elements interposed between the rotating-side raceway ring and the fixed-side raceway ring, An annular detected member fixed to the rotating-side raceway ring of the bearing, the detected member having an annular core metal and a detected portion having two rows of magnetic tracks provided over the circumferential direction of the core metal, A rotation sensor unit fixed to the fixed-side raceway ring of the bearing, the rotation sensor unit having one rotation sensor for non-contact detection of the rotation of the detected portion, a sensor substrate on which the rotation sensor is mounted, and a sensor housing covering the sensor substrate and to which the sensor substrate is attached, An absolute rotation sensor-equipped bearing device comprising: A housing portion of the sensor housing for housing the sensor substrate, the housing portion including a resin material filled in a space between an inner wall surface of the housing portion and the sensor substrate, and a lid member covering an end portion of the housing portion on the side opposite to the bearing and detachably attached to an end portion of the sensor housing, An absolute rotation sensor-equipped bearing device comprising the above.

2. The absolute rotation sensor-equipped bearing device according to Claim 1, wherein a mounting groove into which the sensor substrate is inserted and which positions the sensor substrate in the axial direction and the radial direction is formed in the sensor housing.

3. The absolute rotation sensor-equipped bearing device according to Claim 1 or 2, wherein the sensor substrate is positioned with reference to an end portion of the detected member.

4. The absolute rotation sensor-equipped bearing device according to any one of Claims 1 to 3, wherein a convex portion provided on the sensor housing has a guide surface capable of guiding a member externally fitted to the convex portion in a direction orthogonal to the axial direction.

5. The absolute rotation sensor-equipped bearing device according to any one of Claims 1 to 4, wherein the sensor housing is configured to be able to insert the sensor substrate into the mounting groove from the side opposite to the bearing.

6. The absolute rotation sensor-equipped bearing device according to any one of Claims 1 to 5, A bearing device mounted on an electric vertical takeoff and landing aircraft that includes a plurality of drive units each having a rotary wing and a motor for rotating the rotary wing, and flies by the rotation of the rotary wing, An absolute rotary sensor-equipped bearing device including a bearing that rotatably supports a rotating shaft of the drive unit.

7. In the absolute rotary sensor-equipped bearing device according to any one of Claims 1 to 6, The absolute rotary sensor-equipped bearing device in which the rotary sensor is attached to the sensor housing in a state where the centers of the raceway grooves of the rotary-side raceway ring and the fixed-side raceway ring coincide.

8. In the absolute rotary sensor-equipped bearing device according to Claim 7, the amount of axial movement of the detected portion is 5 times or less the radial internal clearance centered on the groove bottom of each raceway ring. An absolute rotary sensor-equipped bearing device.

9. A bearing having a rotary-side raceway ring, a fixed-side raceway ring arranged to face the rotary-side raceway ring, and rolling elements interposed between the rotary-side raceway ring and the fixed-side raceway ring, A detected member that is an annular detected member fixed to the rotary-side raceway ring of the bearing, and has an annular core metal and a detected portion having two rows of magnetic tracks provided in the circumferential direction of the core metal, A rotary sensor unit fixed to the fixed-side raceway ring of the bearing, including one rotary sensor that non-contact detects the rotation of the detected portion, a sensor substrate on which the rotary sensor is mounted, and a sensor housing that covers the sensor substrate and to which the sensor substrate is attached. A rotary sensor unit having, A sensor positioning method for an absolute rotary sensor-equipped bearing device, comprising: A rotary sensor positioning method in which the rotary sensor is attached to the sensor housing in a state where the centers of the raceway grooves of the rotary-side raceway ring and the fixed-side raceway ring and the center of the rolling element coincide.

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