Rotation sensor device, rotation sensor unit, method for mounting the rotation sensor device

Abstract

To provide a magnetic rotation sensor device allowing the center of a functional film to be positioned on a rotation axis.SOLUTION: A rotation sensor device 3 detects rotational state of a magnetic field generation part 2 rotating around a rotation axis O, such as rotation angle θ. The magnetic field generation part 2 generates magnetic field H symmetrical to the rotation axis O, and includes all or at least part of cylindrical surfaces 22 located a first distance R1 away from the rotation axis O. The rotation sensor device 3 comprises: a functional film 42 including a magnetic detection element 42E detecting the magnetic field H generated by the magnetic field generation part 2; and a guide member 52 provided with a second distance R2 from a normal line N passing through the center of the functional film 42. The second distance R2 is same as or slightly greater than the first distance R1, and the guide member 52 is disposed facing the cylindrical surface 22.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to a rotational sensor device, a rotational sensor unit, and a method for attaching a rotational sensor device.

Background Art

[0002] As a rotational sensor device for measuring a rotational state such as a rotational angle, a rotational speed, and a rotational speed at an end of a rotating body, a magnetic type, an optical type, an electromagnetic induction type, etc. are known. The optical rotational sensor device measures a rotational angle using a slit protruding radially from an output shaft (see, for example, Patent Document 1). Similarly, the electromagnetic induction type rotational sensor device measures a rotational angle using a coil protruding radially from an output shaft. In those devices, as the measurement resolution and measurement accuracy increase, the slit and the coil become larger, so it is difficult to miniaturize the device. On the other hand, the magnetic rotational sensor device measures a rotational angle using a magnet attached on the axial extension of the output shaft. Therefore, the magnetic rotational sensor device can achieve miniaturization of the device and reduction of manufacturing costs as compared with rotational sensor devices of other principles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the magnetic rotational sensor device, a measurement error occurs when the detection point of the magnetic sensor is deviated from the rotation center of the output shaft. Although the rotational sensor device and the housing can be aligned by marking the housing of the motor or the like, there is a deviation within the range of assembly accuracy between the housing and the rotating body. It is preferable to directly align the rotating body and the rotational sensor device. Although the position can be adjusted while attaching the rotational sensor device and checking an electronic signal, the assembly procedure becomes complicated and the burden on the operator is large.

[0005] This disclosure has been made in view of these circumstances and aims to provide a technology that enables the center of a functional film to be aligned on the rotation axis in a magnetic rotation sensor device. [Means for solving the problem]

[0006] A rotation sensor device according to one aspect of the present disclosure is a rotation sensor device for detecting the rotation state of a magnetic field generating unit that rotates about a rotation axis. The magnetic field generating unit generates a magnetic field symmetric with respect to the rotation axis and has at least a portion of a cylindrical surface which is all or part of a cylindrical surface located at a first distance from the rotation axis. The rotation sensor device comprises a functional film including a magnetic detection element for detecting the magnetic field generated by the magnetic field generating unit, and a guide portion provided at a second distance from a normal passing through the center of the functional film. The second distance is the same as or slightly greater than the first distance, and each of the plurality of guide portions is arranged to face at least a portion of the cylindrical surface.

[0007] A rotation sensor unit according to one embodiment of the present disclosure comprises a magnetic field generating unit that rotates about a rotation axis, and a rotation sensor device for detecting the rotation state of the magnetic field generating unit. The magnetic field generating unit generates a magnetic field symmetric with respect to the rotation axis and has at least a portion of a cylindrical surface which is all or part of a cylindrical surface located at a first distance from the rotation axis. The rotation sensor device comprises a functional film including a plurality of magnetic detection elements for detecting the magnetic field generated by the magnetic field generating unit, and a guide portion provided at a second distance from the normal passing through the center of the functional film. The second distance is the same as or slightly greater than the first distance, and the guide portion is arranged to face the cylindrical surface.

[0008] A method for mounting a rotation sensor device according to one embodiment of the present disclosure is a method for mounting a rotation sensor device that detects the rotation state of a magnetic field generating part that rotates around a rotation axis. The magnetic field generating part generates a magnetic field symmetric with respect to the rotation axis and has at least a portion of a cylindrical surface which is all or part of a cylindrical surface located at a first distance from the rotation axis. The rotation sensor device includes a functional film containing a magnetic detection element for detecting the magnetic field generated by the magnetic field generating part, and a guide part provided at a second distance from the normal passing through the center of the functional film. The second distance is the same as or slightly greater than the first distance. The method includes fixing the magnetic field generating part to the tip of a rotating body, placing the rotation sensor device over the magnetic field generating part so that the guide part faces at least a portion of the cylindrical surface, and fixing the rotation sensor device, whose movement is restricted by the positional relationship between at least a portion of the cylindrical surface and the guide part, to a housing that rotatably supports the rotating body.

[0009] According to these embodiments, the center of the functional membrane can be aligned on the rotation axis by the cylindrical surface of the magnetic field generating unit and the guide unit of the rotation sensor device.

[0010] In the above embodiment, at least a portion of the guide portion may be in contact with at least a portion of the cylindrical surface.

[0011] According to this embodiment, the rotation sensor device can be precisely positioned in the magnetic field generating unit.

[0012] In the above embodiment, the gap between the guide portion and at least a portion of the cylindrical surface may be 0.2 mm or less.

[0013] According to this embodiment, a gap may be present between the magnetic field generating unit and the rotation sensor device, thereby suppressing power loss due to frictional resistance.

[0014] In the above embodiment, there may be multiple guide sections. In other words, at least one guide section may include multiple guide sections.

[0015] In this embodiment, the contact area can be reduced compared to an embodiment in which one guide portion is formed in a ring shape and faces the cylindrical surface from all directions, thereby suppressing power loss due to frictional resistance.

[0016] In the above embodiment, the multiple guide portions may be formed of polyacetal resin, polyamide resin, or polybutylene terephthalate resin.

[0017] According to this embodiment, a guide section with excellent properties such as mechanical strength, wear resistance, and self-lubrication can be obtained.

[0018] In the above embodiment, a cavity is formed to house the magnetic field generating section, and each of the multiple guide sections may be formed in a hemispherical shape protruding from the inner wall of the cavity toward the normal.

[0019] In the above embodiment, a cavity is formed to house the magnetic field generating section, and each of the multiple guide sections is flush with the inner wall of the cavity on the side closer to the functional film than a plane perpendicular to the normal, and protrudes from the inner wall of the cavity on the side further from the functional film than the plane, and may be inclined such that the amount of protrusion decreases as it moves away from the functional film.

[0020] According to these embodiments, the contact area between the cylindrical surface and the tip of the guide portion is small, thus suppressing power loss due to frictional resistance. The guide portion is inclined such that the amount of protrusion decreases as it moves away from the functional film in a plane perpendicular to the normal, making it easy to attach a rotation sensor device to the magnetic field generating portion. If the inner wall of the cavity is flush with the functional film on the side closer to the functional film than the plane perpendicular to the normal, it is less likely to get caught when removing the molded product, including the guide portion, from the mold using the plane as the mold dividing surface.

[0021] In the above embodiment, a cavity is formed to house the magnetic field generating unit, and when viewed along the normal, at least a portion of the contour of the cavity is a tangent to a circle which is the contour of at least a portion of the cylindrical surface, and the plurality of guide portions may be points of contact between the tangent and the circle.

[0022] According to this aspect, a guide portion having a shape that is not a protruding portion can be selected.

[0023] In the above aspect, each of the plurality of guide portions may be provided on a guide member that is an integral structure.

[0024] When a plurality of guide portions are provided on a separable structure, the positional relationship between the plurality of guide portions is likely to shift depending on the assembly accuracy and cumulative dimensional tolerances of the plurality of components constituting the structure. According to this aspect, since each of the plurality of guide portions is provided on a guide member that is an integral structure, the positional relationship between the plurality of guide portions is unlikely to shift.

[0025] In the above aspect, the magnetic field generating portion may be magnetized in a direction orthogonal to the rotation axis and include a magnet disposed on the rotation axis.

[0026] In the above aspect, the magnetic field generating portion may be magnetized parallel to the rotation axis and in opposite directions to each other, and include a pair of magnets symmetrically disposed about the rotation axis.

[0027] According to these aspects, a magnetic field generating portion that generates a magnetic field symmetric about the rotation axis can be obtained.

[0028] In the above aspect, the rotational state may be the rotation angle of the magnetic field generating portion.

[0029] According to this aspect, a rotation sensor device can be used as an angle sensor that detects the rotation angle of the magnetic field generating portion.

[0030] The electric motor according to an embodiment of the present disclosure may further include a housing to which the rotation sensor device of the above aspect is attached and an output shaft to which the magnetic field generating portion is attached.

[0031] A rotating mechanism according to one embodiment of the present disclosure may include an electric motor as described above. The rotating mechanism may be an autonomous mobile robot, a battery electric vehicle, a hybrid electric vehicle, an elevator, or an actuator.

[0032] These embodiments allow the rotation sensor device to be applied to various purposes. [Effects of the Invention]

[0033] According to this disclosure, a technology is available that enables the center of a functional film in a magnetic rotation sensor device to be aligned with the rotation axis. [Brief explanation of the drawing]

[0034] [Figure 1] Figure 1 is a perspective view showing an exploded view of a rotation sensor unit according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a perspective view showing a rotation sensor device mounted on the housing of an electric motor. [Figure 3] Figure 3 is a perspective view showing a magnetic field generating unit attached to the output shaft of an electric motor. [Figure 4] Figure 4 is a block diagram showing an example of a rotating mechanism equipped with the electric motor shown in Figure 2. [Figures 5A-5C] Figures 5A to 5C schematically show an example of the magnetic field generating unit shown in Figure 1. [Figure 6] Figure 6 is a bottom view showing the rotation sensor unit shown in Figure 1. [Figure 7] Figure 7 is a bottom view showing the rotation sensor device shown in Figure 6. [Figure 8] Figure 8 is a cross-sectional view of the rotation sensor unit shown in Figure 6. [Figure 9] Figure 9 is a schematic bottom view of the functional membrane shown in Figure 8. [Figure 10]Figure 10 is a flowchart illustrating the method for installing the rotation sensor device. [Figure 11] Figure 11 is a perspective view showing the guide section according to the first embodiment. [Figure 12] Figure 12 is a perspective view showing the guide section according to the second embodiment. [Figure 13] Figure 13 is a schematic bottom view showing the guide section according to the third embodiment. [Figure 14] Figure 14 is a schematic bottom view showing the magnetic field generating unit according to the fourth embodiment. [Figure 15] Figure 15 is a bottom view showing the guide section according to the fifth embodiment. [Modes for carrying out the invention]

[0035] A preferred embodiment will be described with reference to the attached drawings. In each figure, components with the same reference numerals have the same or similar configuration. Each configuration will be described in detail below with reference to Figures 1 to 15.

[0036] Figure 1 is an exploded perspective view of a rotation sensor unit 1 according to one embodiment of the present disclosure. As shown in Figure 1, the rotation sensor unit 1 includes a magnetic field generating unit 2, a rotation sensor device 3, etc. The magnetic field generating unit 2 has at least a portion of a cylindrical surface 22 and an end surface 23, etc. As will be described later, the cylindrical surface 22 may be the entire 360 ​​degrees or a portion of the entire 360 ​​degrees. In the following description, "at least a portion of the cylindrical surface 22" may be simply referred to as "cylindrical surface 22". The rotation sensor device 3 detects the rotation state, such as the rotation angle θ, of the magnetic field generating unit 2 which rotates around the rotation axis O. The housing 31 of the rotation sensor device 3 is provided with a flange 32 having an elongated hole for mounting.

[0037] Figure 2 is a perspective view showing a rotation sensor device 3 attached to the motor housing 110 of an electric motor 100. As shown in Figure 2, the rotation sensor device 3 is fixed to the housing 110 by a tightening screw 33 inserted through an elongated hole in the flange 32. Figure 3 is a perspective view showing a magnetic field generating unit 2 attached to the output shaft 120 of the electric motor 100. The output shaft 120 of the electric motor 100 is an example of a rotating body. The aforementioned housing 110 is an example of a housing that rotatably supports a rotating body such as the output shaft 120.

[0038] In the illustrated example, the magnetic field generating unit 2 is configured to be separable from a rotating body such as the output shaft 120. The magnetic field generating unit 2 is formed, for example, in a cylindrical shape and rotates together with the rotating body when fixed to it by embedded screws 24 or the like. The configuration of the magnetic field generating unit 2 is not limited to the illustrated example, and it may be embedded in the rotating body to form an integrated structure.

[0039] Figure 4 is a block diagram showing an example of a rotating mechanism 200 equipped with the electric motor 100 shown in Figure 2. The rotating mechanism 200 includes a load 230 that is rotationally driven by the electric motor 100 equipped with a rotation sensor unit 1. In the illustrated example, the rotating mechanism 200 is configured as an autonomous mobile robot that automatically avoids workers and obstacles while transporting cargo.

[0040] The rotating mechanism 200 is not limited to an autonomous mobile transport robot, but may also be an electric vehicle (Battery Electric Vehicle), a hybrid electric vehicle, an elevator, or an actuator.

[0041] The autonomous mobile transport robot includes a load 230 that is rotationally driven by the electric motor 100, wheels 232 for travel, a transmission mechanism 231 connecting the output shaft 120 of the electric motor 100 and the wheels 232, etc. The autonomous mobile transport robot may further include a power supply unit 220 such as a battery that supplies power to the electric motor 100, a control unit 210 that controls the power supply unit 220, etc. The control unit 210 sends a motor drive signal to the power supply unit 220 based on a feedback signal received from the rotation sensor unit 1, and controls the rotation of the electric motor 100.

[0042] Figures 5A to 5C schematically show an example of the magnetic field generating unit 2 shown in Figure 1. The magnetic field generating unit 2 generates a magnetic field H that is symmetrical with respect to the rotation axis O. In the example shown in Figure 5A, the magnetic field generating unit 2 includes a magnet 21 that is magnetized in a direction perpendicular to the rotation axis O and is positioned on the rotation axis O. In the example shown in Figure 5A, the north and south poles of the magnet 21 are in symmetrical positions with respect to the rotation axis O. The magnet 21 may not be disc-shaped but a bar magnet with both ends magnetized as north and south poles, respectively.

[0043] In the examples shown in Figures 5B and 5C, the magnetic field generating unit 2 includes a pair of magnets 21 that are magnetized parallel to the rotation axis O and whose magnetization directions are opposite to each other. The pair of magnets 21 are arranged symmetrically with respect to the rotation axis O. More specifically, in the example shown in Figure 5A, the pair of magnets 21 are arranged in close proximity to each other. In the example shown in Figure 5C, the pair of magnets 21 are arranged spaced apart from each other. In the examples shown in Figures 5B and 5C, the north pole of one magnet 21 is symmetrically positioned to the south pole of the other magnet 21 with respect to the rotation axis O. Similarly, the south pole of one magnet 21 is symmetrically positioned to the north pole of the other magnet 21 with respect to the rotation axis O. It is also known that the magnetic field H is strengthened when a yoke is present on the bottom side.

[0044] When using a magnetic field generated from multiple poles, it is more difficult to achieve high accuracy compared to using a magnetic field generated from only two poles, a north pole and a south pole, due to the influence of magnetization accuracy. In all the examples shown in Figures 5A to 5C, a magnetic field H can be generated from only two poles, a north pole and a south pole.

[0045] Figure 6 is a bottom view showing the rotation sensor unit 1 shown in Figure 1. As shown in Figure 6, the rotation sensor device 3 includes a substrate 4, a guide member 5, etc., housed in a housing 31. A cavity 51 for housing the magnetic field generating unit 2 is formed in the guide member 5.

[0046] The guide member 5 includes at least one guide portion 52. Preferably, there are three or more guide portions 52. In the illustrated example, four guide portions 52 are formed. The number of guide portions 52 may be one. In that case, the shape of the guide portion 52 may be a cylinder conforming to the cylindrical surface 22 around the entire 360 ​​degrees, or a concave cylindrical surface conforming to a portion of the cylindrical surface 22.

[0047] The guide member 5, which includes multiple guide portions 52, is preferably made of an engineering plastic such as polyacetal resin, polyamide resin, or polybutylene terephthalate resin, which has excellent properties such as mechanical strength, wear resistance, and self-lubrication. Each of the multiple guide portions 52 is arranged to face the cylindrical surface 22 of the magnetic field generating portion 2. In the illustrated example, at least a portion of the multiple guide portions 52 is in contact with the cylindrical surface 22. The guide member 52 may wear down during use of the rotation sensor unit 1, and the guide portions 52 may no longer be in contact with the cylindrical surface 22.

[0048] Figure 7 is a bottom view of the rotation sensor device 3 shown in Figure 6. As shown in Figure 7, the substrate 4 is equipped with a magnetic sensor 41 for detecting the rotational state of the magnetic field generating unit 2, such as the rotation angle θ, and connectors 44 for connecting to power supplies and external devices. The substrate 4 may be a rigid substrate or a flexible substrate.

[0049] Figure 8 is a cross-sectional view of the rotation sensor unit 1 shown in Figure 6. As shown in Figure 8, the magnetic sensor 41 has a functional film 42 facing the end face 23. The end face 23 is parallel to the XY plane, which will be described later. Each of the multiple guide portions 52 is provided at a second distance R2 from the normal N passing through the center of the functional film 42. In the illustrated example, the distance from the tip (vertex) of the guide portion 52 to the normal N is the second distance R2. Furthermore, in the illustrated example, it is possible to draw a circle with a radius of the second distance R2 passing through the tips of all the guide portions 52.

[0050] The magnetic field generating unit 2 has at least a portion of a cylindrical surface 22, which is all or part of a cylindrical surface located at a first distance R1 from the rotation axis O. Alternatively, the magnetic field generating unit 2 may be described as having at least a portion of a cylindrical surface 22, which is formed by the rotation of a generatrix L located at a first distance R1 from the rotation axis O. The second distance R2 is the same as the first distance R1, or slightly greater than the first distance R1.

[0051] Figure 9 is a schematic bottom view of the functional film 42 shown in Figure 8. As shown in Figure 9, the functional film 42 includes at least one magnetic detection element 42E that detects the magnetic field H generated by the magnetic field generating unit 2 and generates a detection signal. In the illustrated example, the functional film 42 includes at least one magnetic detection element array 42A, an inorganic film surrounding the magnetic detection element array 42A, etc. Each magnetic detection element array 42A is composed of a plurality of magnetic detection elements 42E connected in a chain and arranged in a matrix.

[0052] The inorganic film may be an inorganic film mainly composed of silica (silicon dioxide SiO2), or it may be a laminated film of an inorganic film mainly composed of silica and an inorganic film mainly composed of alumina (aluminum oxide Al2O3). In the illustrated example, the functional film 42 includes four magnetic detection arrays 42A, and the four magnetic detection arrays 42A are connected to each other by a wiring layer 42W.

[0053] The detection point of the magnetic sensor 41 is the center of the functional film 42. When there are two or more magnetic detection element arrays 42A, the magnetic detection element arrays 42A are arranged point-symmetrically with respect to the center of the functional film 42. In other words, the center of symmetry of the multiple magnetic detection element arrays 42A is the center of the functional film 42. When there is one magnetic detection element array 42A, the center of the magnetic detection element array 42A is the center of the functional film 42. When there is one magnetic detection element 42E, the center of the magnetic detection element 42E is the center of the functional film 42.

[0054] When each magnetic detection element array 42A is composed of multiple magnetic detection elements 42E connected in a chain and arranged in a matrix, the multiple magnetic detection elements 42E are arranged along the XY plane. The normal N of the functional film 42 is perpendicular to the XY plane and parallel to the direction Z perpendicular to the plane.

[0055] An example of a magnetic detection element 42E is a TMR (Tunneling magnetoresistance effect) element. The magnetic detection element 42E is not limited to a TMR element, but may also be a GMR (Giant magnetoresistance effect) element, an AMR (Anisotropic magnetoresistance effect) element, a Hall element, or any other type of magnetic detection element. Compared to other types of MR elements, TMR elements have a smaller junction area, allowing for miniaturization of the magnetic sensor 41, and have a larger MR ratio, enabling a higher output from the magnetic sensor 41, making them particularly suitable for the magnetic detection element 42E.

[0056] The rotation sensor device 3 detects a first component of the magnetic field H generated by the magnet 21 that is applied to the rotation sensor device 3, in a direction parallel to the X direction, and generates a first detection signal representing the strength of the first component. It also detects a second component of the magnetic field H generated by the magnet 21 that is parallel to the Y direction, and generates a second detection signal representing the strength of the second component. The processor calculates the rotation angle θ that the magnetic field H generated by the magnet 21 makes with respect to the reference direction by calculating the arctangent of the ratio of the first detection signal and the second detection signal. The magnetic sensor 41 may include an ASIC (Application Specific Integrated Circuit) 43 including a processor, etc.

[0057] Figure 10 is a flowchart illustrating the method for mounting the rotation sensor device. As shown in Figure 10, the mounting method for the rotation sensor device 3 is as follows: Step S1: The magnetic field generating unit 2 is fixed to the tip of a rotating body such as the output shaft 120. Step S2: The rotation sensor device 3 is placed over the magnetic field generating unit 2 so that the guide unit 52 faces at least a portion of the cylindrical surface 22. Step S3: The rotation sensor device 3 is fixed to the housing 110 that rotatably supports the rotating body such as the output shaft 120, in a state where its movement is restricted by the positional relationship between at least a portion of the cylindrical surface 22 and the guide unit 52.

[0058] Figure 11 is a perspective view showing a guide portion 52 according to the first embodiment. As shown in Figure 11, each of the plurality of guide portions 52 may be formed in a hemispherical shape protruding from the inner wall of the cavity 51 toward the normal N.

[0059] Figure 12 is a perspective view showing a guide portion 52 according to the second embodiment. As shown in Figure 12, each of the plurality of guide portions 52 may be flush with the inner wall of the cavity 51 on the side closer to the functional film 42 than a virtual plane P perpendicular to the normal N, and protrude from the inner wall of the cavity 51 on the side further from the functional film 42 than plane P, and may be inclined such that the amount of protrusion from the cavity 51 decreases as it moves away from the functional film 42. In the illustrated example, each of the plurality of guide portions 52 is formed in a spherical shape divided into approximately four equal parts.

[0060] Figure 13 is a schematic bottom view showing the guide portion 52 according to the third embodiment. As shown in Figure 13, when viewed along the normal N, at least a portion of the contour of the cavity 51 is a tangent to the circle which is the contour of the cylindrical surface 22, and the multiple guide portions 52 may be points of contact between such tangents and the circle.

[0061] In the illustrated example, the cavity 51 is configured as a polygonal hole that penetrates the guide member 5 in a direction Z perpendicular to the surface and parallel to the normal N. Instead of a through hole, an L-shaped notch may be formed in the guide member 5, and the space between the notch and the housing 31 may be configured as the cavity.

[0062] Figure 14 is a schematic bottom view showing a magnetic field generating unit according to the fourth embodiment. In the illustrated example, the magnetic field generating unit 2 has a cylindrical surface 22 that does not extend 360 degrees around its circumference. To make it clearer that it is a part of a cylindrical surface that extends 360 degrees around its circumference, the term "cylindrical surface 22" may be replaced with "partial cylindrical surface 22". In the circumferential direction of the cylindrical surface 22, one end of the cylindrical surface 22 is connected to the other end by a connecting surface 25. The connecting surface 25 may be a flat surface, a convex surface with a different curvature from the cylindrical surface 22, or a concave surface.

[0063] For example, in construction machinery such as excavators, the rotation angle of the bucket and arm is less than 360 degrees. The rotation sensor unit 1 of this disclosure may be attached to detect the rotation angle of the bucket and arm. In that case, the rotation sensor unit 1 equipped with the magnetic field generating unit 2 of the fourth embodiment may also be used.

[0064] In the illustrated example, there are two guide sections 52 as multiple guide sections 52. If there are two or more guide sections 52, the distance from each of the two guide sections 52 to the normal vector N is known by the second distance R2, and the distance between the two guide sections 52 is known, so the position of the normal vector N can be calculated from the two guide sections 52. By arranging the guide sections 52 so as to face the cylindrical surface 22, the normal vector N can be aligned with the axis of rotation O.

[0065] Figure 15 is a bottom view showing the guide portion 52 according to the fifth embodiment. As shown in Figure 15, there may be a gap G between each of the multiple guide portions 52 and the cylindrical surface 22. In the illustrated example, the gap G between each of the multiple guide portions 52 and the cylindrical surface 22 is in the range of 0.1 mm or more and 0.2 mm or less, and the position of the rotation sensor device 3 is adjusted so that all the gaps G are equal to each other when viewed visually.

[0066] With the rotation sensor device 3 and related technologies of this disclosure configured as described above, the center of the functional film 42 can be aligned on the rotation axis O by the cylindrical surface 22 of the magnetic field generating unit 2 and the plurality of guide parts 52 of the rotation sensor device 3. This reduces errors caused by misalignment between the magnetic field generating unit 2 and the magnetic sensor 41.

[0067] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The elements, arrangement, materials, conditions, shapes, and sizes of the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined. For example, the guide portion may be provided on the cylindrical surface 22 of the magnetic field generating portion 2 instead of the guide member 5. [Explanation of Symbols]

[0068] 1...Rotation sensor unit, 2...Magnetic field generator, 21...Magnet, 22...Cylindrical surface, 23...End face, 24...Embedded screw, 25...Connection surface, 3...Rotation sensor device, 31...Housing, 32...Flange, 33...Tightening screw, 4...Substrate, 41...Magnetic sensor, 42...Functional film, 42A...Magnetic detection element array, 42E...Magnetic detection element, 42W...Wiring layer, 43...ASIC, 44...Connector, 5...Guy Component, 51...cavity, 52...guide section, 100...motor motor, 110...housing, 120...output shaft, 200...rotation mechanism, 210...control section, 220...power supply section, 230...load, 231...transmission mechanism, 232...wheel, G...gap, H...magnetic field, L...busbar, N...normal, O...rotation axis, P...plane, R1...first distance, R2...second distance, X,Y...in-plane direction, Z...perpendicular direction, θ...rotation angle.

Claims

1. A magnetic field generating unit that rotates around a rotation axis, The system includes a rotation sensor device for detecting the rotation state of the magnetic field generating unit, The magnetic field generating unit generates a magnetic field symmetrical with respect to the rotation axis and has at least a portion of a cylindrical surface which is all or part of a cylindrical surface located at a first distance from the rotation axis. The rotation sensor device is A functional film including a magnetic detection element that detects the magnetic field generated by the magnetic field generating unit, The functional film comprises a plurality of guide portions provided at a second distance from the normal passing through the center of the functional film, The second distance is the same as the first distance or slightly greater than the first distance. The guide portion is arranged to face the cylindrical surface. Rotation sensor unit.

2. At least a portion of the guide portion is in contact with the cylindrical surface. The rotation sensor unit according to claim 1.

3. The gap between the guide portion and the cylindrical surface is 0.2 mm or less. The rotation sensor unit according to claim 1.

4. Multiple guide sections are provided. The rotation sensor unit according to claim 1.

5. The guide portion is made of polyacetal resin, polyamide resin, or polybutylene terephthalate resin. The rotation sensor unit according to claim 1.

6. A cavity is formed to house the magnetic field generating unit. Each of the aforementioned guide portions is formed in a hemispherical shape, protruding from the inner wall of the cavity toward the normal. The rotation sensor unit according to claim 4.

7. Each of the plurality of guide portions is formed in a spherical shape divided into approximately four equal parts, The rotation sensor unit according to claim 1.

8. A cavity is formed to house the magnetic field generating unit. When viewed along the aforementioned normal, at least a portion of the cavity's contour is a tangent to the circle that is the contour of the cylindrical surface. The aforementioned plurality of guide portions are the points of contact between the tangent line and the circle. The rotation sensor unit according to claim 4.

9. Each of the aforementioned plurality of guide sections is provided on a guide member which is an integral structure. The rotation sensor unit according to claim 4.

10. The magnetic field generating unit includes a magnet that is magnetized in a direction perpendicular to the rotation axis and is positioned on the rotation axis. The rotation sensor unit according to claim 1.

11. The magnetic field generating unit includes a pair of magnets that are magnetized parallel to the rotation axis and in opposite directions, and are arranged symmetrically with respect to the rotation axis. The rotation sensor unit according to claim 1.

12. The aforementioned rotation state is the rotation angle of the magnetic field generating unit. The rotation sensor unit according to claim 1.

13. The rotation sensor unit is provided as described in claim 1, A housing to which the aforementioned rotation sensor device is attached, The output shaft to which the magnetic field generating unit is attached further comprises, Electric motor.

14. The electric motor is provided as described in claim 13. Rotating mechanism.

15. A method for mounting a rotation sensor device that detects the rotational state of a magnetic field generating part that rotates around a rotation axis, The magnetic field generating unit generates a magnetic field symmetrical with respect to the rotation axis and has at least a portion of a cylindrical surface at a first distance from the rotation axis. The rotation sensor device is A functional film including a plurality of magnetic detection elements for detecting the magnetic field generated by the magnetic field generating unit, The functional film comprises a plurality of guide portions provided at a second distance from the normal passing through the center of the functional film, The second distance is the same as the first distance or slightly greater than the first distance. The aforementioned method, The magnetic field generating unit is fixed to the tip of the rotating body. The rotation sensor device is placed over the magnetic field generating section so that the guide section faces at least a portion of the cylindrical surface, and This includes fixing the rotation sensor device, whose movement is restricted by the positional relationship between the cylindrical surface and the guide portion, to a housing that rotatably supports the rotating body, How to install the angle sensor.

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