Rotation sensor device, rotation sensor unit, and method for installing the rotation sensor device

Abstract

To provide a magnetic rotation sensor device allowing the center of a detection part including a magnetic detection element 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 a cylindrical surface 22 with the rotation axis O as center. The rotation sensor device 3 comprises: a magnetic detection element 42E detecting the magnetic field H generated by the magnetic field generation part 2; and a guide member 5 that is deformable into a first shape of being in contact with the cylindrical surface 22 and a second shape of being away from the cylindrical surface 22.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present disclosure relates to a rotation sensor device, a rotation sensor unit, and a method for installing a rotation sensor device. [Background technology]

[0002] Known rotation sensor devices for measuring rotational conditions such as rotation angle, rotation speed, and rotation count at the end of a rotating body include magnetic, optical, and electromagnetic induction types. Optical rotation sensor devices measure the rotation angle using a slit protruding radially from the output shaft (see, for example, Patent Document 1). Similarly, electromagnetic induction rotation sensor devices measure the rotation angle using a coil protruding radially from the output shaft. In these devices, the slit and coil become larger as the measurement resolution and measurement accuracy increase, making it difficult to miniaturize the device. In contrast, magnetic rotation sensor devices measure the rotation angle using a magnet attached to the axial extension of the output shaft. Therefore, magnetic rotation sensor devices can be made more compact and less expensive to manufacture than rotation sensor devices based on other principles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 6,563,108 Summary of the Invention [Problem to be solved by the invention]

[0004] However, magnetic rotation sensor devices suffer from measurement errors when the detection point of the magnetic sensor chip is misaligned with the center of rotation of the output shaft. While it is possible to align the rotation sensor device with the housing of an electric motor or the like by marking the housing, there is still some misalignment between the housing and the rotating body within the range of assembly accuracy. It is preferable to directly align the rotating body with the rotation sensor device. It is also possible to adjust the position by installing the rotation sensor device and checking the electronic signal, but this requires a complicated assembly procedure and places a heavy burden on the worker.

[0005] The present disclosure has been made in consideration of these circumstances, and aims to provide a technology that can align the center of a detection unit including a magnetic detection element 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 that detects the rotation state of a magnetic field generating unit that rotates around a rotation axis. The magnetic field generating unit generates a magnetic field symmetrical with respect to the rotation axis and has a cylindrical surface centered on the rotation axis. The rotation sensor device includes a magnetic detection element that detects the magnetic field generated by the magnetic field generating unit, and a guide member that is deformable into a first shape in contact with the cylindrical surface and a second shape spaced apart from the cylindrical surface.

[0007] A rotation sensor unit according to one embodiment of the present disclosure includes a magnetic field generating unit that rotates about a rotation axis and a rotation sensor device that detects 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 a cylindrical surface centered on the rotation axis. The rotation sensor device includes a magnetic detection element that detects the magnetic field generated by the magnetic field generating unit, and a guide member that is deformable into a first shape in contact with the cylindrical surface and a second shape spaced apart from the cylindrical surface.

[0008] A method for installing a rotation sensor device according to one embodiment of the present disclosure is a method for installing a rotation sensor device that detects the rotation state of a magnetic field generating unit that rotates around a rotation axis. The magnetic field generating unit generates a magnetic field symmetrical with respect to the rotation axis and has a cylindrical surface centered on the rotation axis. The rotation sensor device includes a magnetic detection element that detects the magnetic field generated by the magnetic field generating unit, and a guide member that is deformable into a first shape in contact with the cylindrical surface and a second shape spaced apart from the cylindrical surface. The method includes fixing the magnetic field generating unit to the tip of a rotating body, placing the rotation sensor device over the magnetic field generating unit and bringing the guide member of the first shape into contact with the cylindrical surface, fixing the rotation sensor device, whose movement is restricted by contact between the cylindrical surface and the guide member, to a housing that rotatably supports the rotating body, and deforming the guide member from the first shape to the second shape.

[0009] According to these aspects, the cylindrical surface of the magnetic field generating unit and the guide member of the rotation sensor device can align the center of the detection unit including the magnetic detection element on the rotation axis. Errors caused by misalignment between the magnetic field generating unit and the magnetic sensor chip can be reduced. By separating the guide member from the cylindrical surface, power loss due to frictional resistance can be suppressed.

[0010] In the above aspect, the guide member may include elastically deformable first and second arms, and a pressing member that presses the first and second arms, and when the pressing member presses the first and second arms against the biasing force, the guide member may deform from the first shape to the second shape or from the second shape to the first shape, and when the pressing member moves away from the first and second arms, the restoring force of the first and second arms may deform the guide member from the second shape to the first shape or from the first shape to the second shape.

[0011] According to this aspect, the guide member is deformed by the elastic deformation of the first arm and the second arm without using a complex mechanism, and a deformable guide member can be configured with a small number of parts.

[0012] In the above aspect, the guide member may further include a connecting member that connects the first arm and the second arm when in the first shape, and the pressing member may cut the connecting member when the guide member is transformed from the first shape to the second shape.

[0013] According to this aspect, the connecting portion improves the dimensional accuracy of the guide member, so that the rotation sensor device can be aligned with the magnetic field generating portion with high accuracy.

[0014] In the above aspect, the guide member may include a pressing member that moves along a first axis perpendicular to the rotation axis, a first arm that has a first inclined surface facing the pressing member and is elastically deformable, and a second arm that has a second inclined surface facing the pressing member and is elastically deformable, and in the first shape, the first inclined surface and the second inclined surface are inclined so as to approach the first axis as they approach the rotation axis, and when the pressing member is brought closer to the rotation axis, the pressing member presses the first inclined surface and the second inclined surface against the biasing force, causing the first arm and the second arm to move away from the cylindrical surface and assume the second shape.

[0015] In the above aspect, the guide member may include a pressing member that moves along a first axis perpendicular to the rotation axis, a first arm that has a first inclined surface facing the pressing member and is elastically deformable, and a second arm that has a second inclined surface facing the pressing member and is elastically deformable, and in the first shape, the first inclined surface and the second inclined surface are inclined so as to move away from the first axis as they approach the rotation axis, and when the pressing member is moved away from the rotation axis, the pressing member presses the first inclined surface and the second inclined surface against the biasing force, causing the first arm and the second arm to move away from the cylindrical surface and deform to the second shape.

[0016] According to these aspects, the guide member is deformed into the second shape using the first inclined surface, the second inclined surface, and the pressing member without using a complex mechanism, and a deformable guide member can be configured with a small number of parts.

[0017] In the above aspect, a linear motion mechanism that converts the rotational motion into linear motion of the pressing member may be further provided.

[0018] According to this aspect, the first inclined surface and the second inclined surface can be pressed by the pressing member without using a complex mechanism. The linear motion mechanism is not particularly limited, and may be a ball screw, a rack and pinion, or another type.

[0019] In the above aspect, the rotation state may be a rotation angle of the magnetic field generating unit.

[0020] According to this aspect, the rotation sensor device can be used as an angle sensor that detects the rotation angle of the magnetic field generating unit.

[0021] An electric motor according to one embodiment of the present disclosure may include the rotation sensor unit of the above aspect, and may further include a housing to which the rotation sensor device is attached, and an output shaft to which a magnetic field generating unit is attached.

[0022] A rotation mechanism according to an embodiment of the present disclosure may include the electric motor of the above aspect. The rotation mechanism may be an autonomous mobile robot, a battery electric vehicle, a hybrid electric vehicle, an elevator, or an actuator.

[0023] These aspects allow the rotation sensor device to be applied for various purposes. [Effects of the Invention]

[0024] According to the present disclosure, it is possible to provide a technique that can align the center of a detection unit including a magnetic detection element on the rotation axis in a magnetic rotation sensor device. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is an exploded perspective view of a rotation sensor unit according to an embodiment of the present disclosure. [Figure 2]FIG. 2 is a perspective view showing a rotation sensor device attached to a housing of an electric motor. [Figure 3] FIG. 3 is a perspective view showing a magnetic field generating unit attached to the output shaft of the electric motor. [Figure 4] FIG. 4 is a block diagram showing an example of a rotation mechanism including the electric motor shown in FIG. [Figures 5A-5C] 5A to 5C are diagrams schematically illustrating an example of the magnetic field generating unit shown in FIG. [Figure 6] FIG. 6 is a bottom view showing the first shape of the guide member according to the first embodiment. [Figure 7] FIG. 7 is a bottom view showing the rotation sensor device shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view of the rotation sensor unit shown in FIG. [Figure 9] FIG. 9 is a bottom view schematically showing the functional film shown in FIG. [Figure 10] FIG. 10 is a perspective view showing an example of a guide portion provided on a guide member. [Figure 11] FIG. 11 is a perspective view showing a modified example of the guide portion shown in FIG. [Figure 12] FIG. 12 is a bottom view showing the second shape of the guide member according to the first embodiment. [Figure 13] FIG. 13 is a flow chart illustrating a method for mounting the rotation sensor device. [Figure 14] FIG. 14 is a bottom view showing the first shape of the guide member according to the second embodiment. [Figure 15] FIG. 15 is a bottom view showing the second shape of the guide member according to the second embodiment. [Figure 16] FIG. 16 is a plan view showing a first shape of the guide member according to the third embodiment. [Figure 17] FIG. 17 is a plan view showing a second shape of the guide member according to the third embodiment. [Figure 18] FIG. 18 is a side view showing a first shape of the guide member according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] A preferred embodiment will be described with reference to the accompanying drawings. In each drawing, components with the same reference numerals have the same or similar configurations. Each configuration will be described in detail below with reference to Figures 1 to 18.

[0027] FIG. 1 is an exploded perspective view of a rotation sensor unit 1 according to an embodiment of the present disclosure. As shown in FIG. 1, the rotation sensor unit 1 includes a magnetic field generating unit 2, a rotation sensor device 3, and the like. The magnetic field generating unit 2 has at least a portion of a cylindrical surface 22, an end surface 23, and the like. The cylindrical surface 22 may be the entire 360-degree circumference, or may be a portion of the entire 360-degree circumference. 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 rotating about a rotation axis O. A flange 32 having an elongated hole for mounting is provided on a housing 31 of the rotation sensor device 3.

[0028] Fig. 2 is a perspective view showing the rotation sensor device 3 attached to a housing (motor housing) 110 of an electric motor 100. As shown in Fig. 2, the rotation sensor device 3 is fixed to the housing 110 by a fastening screw 33 inserted into an elongated hole in a flange 32. Fig. 3 is a perspective view showing the magnetic field generating unit 2 attached to an output shaft (motor shaft) 120 of the electric motor 100. The output shaft 120 of the electric motor 100 is an example of a rotating body. The above-mentioned housing 110 is an example of a housing that rotatably supports a rotating body such as the output shaft 120.

[0029] 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 the rotating body by an embedded screw 24 or the like. The configuration of the magnetic field generating unit 2 is not limited to the illustrated example, and the magnetic field generating unit 2 may be embedded in the rotating body to form an integrated structure.

[0030] FIG. 4 is a block diagram showing an example of an autonomous mobile robot 200 equipped with the electric motor 100 shown in FIG. 2. The autonomous mobile robot 200 travels and transports luggage while automatically avoiding workers and obstacles. In addition to the electric motor 100 equipped with the rotation sensor unit 1, the autonomous mobile robot 200 further includes wheels 230 driven by the electric motor 100, 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, and the like. The output shaft 120 of the electric motor 100 and the wheels 230 may be connected by a transmission mechanism composed of gears or the like.

[0031] 5A to 5C are diagrams schematically illustrating an example of the magnetic field generating unit 2 shown in FIG. 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 FIG. 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 disposed on the rotation axis O. In the example shown in FIG. 5A, the north and south poles of the magnet 21 are positioned symmetrically with respect to the rotation axis O. The magnet 21 does not have to be disk-shaped, but may be a bar magnet whose ends are magnetized to the north and south poles, respectively.

[0032] In the examples shown in FIGS. 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 have opposite magnetization directions. The pair of magnets 21 are arranged symmetrically with respect to the rotation axis O. More specifically, in the example shown in FIG. 5A, the pair of magnets 21 are arranged close to each other. In the example shown in FIG. 5C, the pair of magnets 21 are arranged spaced apart from each other. In the examples shown in FIGS. 5B and 5C, the north pole of one magnet 21 is symmetrically positioned with respect to the rotation axis O as compared to the south pole of the other magnet 21. Similarly, the south pole of one magnet 21 is symmetrically positioned with respect to the north pole of the other magnet 21 as compared to the rotation axis O.

[0033] When using a magnetic field generated from multiple poles, it is difficult to achieve high accuracy compared to using a magnetic field generated from two poles, an N pole and an S pole, due to the influence of magnetization accuracy. In all of the examples shown in Figures 5A to 5C, a magnetic field H can be generated from two poles, an N pole and an S pole. It is also known that the magnetic field H is strengthened if a yoke is provided on the bottom side.

[0034] When using a magnetic field generated from multiple poles, it is difficult to obtain high accuracy compared to when using a magnetic field generated from two poles, an N pole and an S pole, due to the influence of magnetization accuracy. In all of the examples shown in Figures 5A to 5C, the magnetic field H can be generated from two poles, an N pole and an S pole.

[0035] Fig. 6 is a bottom view showing a first shape of the guide member 5 according to the first embodiment. As shown in Fig. 6, the rotation sensor device 3 includes a substrate 4 and a guide member 5 housed in a housing 31. In the example shown, the guide member 5 includes a pair of a first arm 50L and a second arm 50R, a pressing member 58 that presses the first arm 50L and the second arm 50R, and the like. A cavity 51 that houses the magnetic field generating unit 2 is defined in the space surrounded by the first arm 50L and the second arm 50R.

[0036] The guide member 5 includes a plurality of guide portions 52 provided on the first arm 50L and the second arm 50R. If there are two or more guide portions 52, the distance from each of the two guide portions 52 to the normal N is known as the second distance R2, and the spacing between the two guide portions 52 is also known, so the position of the normal N can be calculated from the two guide portions 52. If the guide portions 52 are arranged to face the cylindrical surface 22, the normal N can be aligned with the rotation axis O. The number of guide portions 52 is preferably three or more. In the illustrated example, a total of four guide portions 52 are formed, two on each of the first arm 50L and the second arm 50R.

[0037] The material of the first arm 50L and the second arm 50R, including the plurality of guide portions 52, is preferably an engineering plastic, such as polyacetal resin, polyamide resin, or polybutylene terephthalate resin, which has excellent mechanical strength and is elastically deformable. Each of the plurality of guide portions 52 is disposed so as to face the cylindrical surface 22 of the magnetic field generating unit 2.

[0038] Fig. 7 is a bottom view showing the rotation sensor device 3 shown in Fig. 6. As shown in Fig. 7, a magnetic sensor chip 41 that detects the rotation state such as the rotation angle θ of the magnetic field generating unit 2, a connector 44 that is connected to a power source or external devices, etc. are mounted on the substrate 4. The substrate 4 may be a rigid substrate or a flexible substrate.

[0039] 8 is a cross-sectional view of the rotation sensor unit 1 shown in FIG. 6. As shown in FIG. 8, the magnetic sensor chip 41 faces the end face 23 and includes a functional film 42. The end face 23 is parallel to the XY plane described below. When the guide member 5 is in the first shape, each of the multiple guide portions 52 is provided at a second distance R2 from a normal line N passing through the center of the functional film 42. In the example shown, the distance from the tip (vertex) of the guide portion 52 to the normal line N is the second distance R2. Furthermore, in the example shown, a circle can be drawn that passes through the tips of all of the guide portions 52 and has a radius of the second distance R2.

[0040] The magnetic field generating unit 2 has at least a partial cylindrical surface 22 that is all or a part of a cylindrical surface that is located at a first distance R1 from the rotation axis O. In other words, the magnetic field generating unit 2 has a cylindrical surface 22 that is at least a part of a cylindrical surface that is formed by rotation of a generatrix L that is located at the first distance R1 from the rotation axis O. The second distance R2 is the same as the first distance R1.

[0041] Fig. 9 is a bottom view schematically showing the functional film 42 shown in Fig. 8. As shown in Fig. 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 example shown, the functional film 42 includes at least one magnetic detection element array 42A, an inorganic film surrounding the magnetic detection element array 42A, and the like. Each magnetic detection element array 42A is made up of a plurality of magnetic detection elements 42E connected in a daisy chain and arranged in a matrix.

[0042] The inorganic film may be an inorganic film whose main component is silica (silicon dioxide SiO2), or may be a laminated film of an inorganic film whose main component is silica and an inorganic film whose main component is 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.

[0043] The detection point of the magnetic sensor chip 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 about 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.

[0044] When each magnetic detection element array 42A is composed of a plurality of magnetic detection elements 42E connected in a daisy chain and arranged in a matrix, the plurality of magnetic detection elements 42E are arranged along the XY plane. A normal N of the functional film 42 is perpendicular to the XY plane and parallel to the direction perpendicular to the surface Z.

[0045] An example of the 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 be a GMR (giant magnetoresistance effect) element, an AMR (anisotropic magnetoresistance effect) element, a Hall element, or another type of magnetic detection element. A TMR element is particularly suitable for the magnetic detection element 42E because, compared to other types of MR elements, it has a smaller junction area, allowing the magnetic sensor chip 41 to be miniaturized, and has a larger MR ratio, allowing the output of the magnetic sensor chip 41 to be increased.

[0046] The rotation sensor device 3 detects a first component of the magnetic field H generated by the magnet 21, which is a magnetic field component applied to the rotation sensor device 3, in a direction parallel to the X direction, and generates a first detection signal representing the intensity of the first component, and detects a second component of the magnetic field H generated by the magnet 21 in a direction parallel to the Y direction, and generates a second detection signal representing the intensity of the second component. The processor calculates the arc tangent of the ratio between the first detection signal and the second detection signal, thereby calculating the rotation angle θ that the magnetic field H generated by the magnet 21 makes with respect to a reference direction. The magnetic sensor chip 41 may include an ASIC (Application Specific Integrated Circuit) 43 including a processor, etc.

[0047] 10 is a perspective view showing an example of a guide portion 52 provided on the guide member 5. As shown in Fig. 10, each of the multiple guide portions 52 may be formed in a hemispherical shape protruding from the inner wall of the cavity 51 toward the normal N. The guide portions 52 are inclined so that the amount of protrusion decreases with increasing distance from the functional film 42 in the plane-perpendicular direction Z parallel to the normal N, which makes it easy to attach the rotation sensor device 3 to the magnetic field generating unit 2.

[0048] 11 is a perspective view showing a modified example of the guide portion 52 shown in FIG. 10. As shown in FIG. 11, each of the multiple guide portions 52 is flush with the inner wall of the cavity 51 on a side closer to the functional film 42 than an imaginary plane P perpendicular to the normal N, and protrudes from the inner wall of the cavity 51 on a side farther from the functional film 42 than the plane P, and may be inclined so that the amount of protrusion from the cavity 51 decreases with increasing distance from the functional film 42. In the example shown, each of the multiple guide portions 52 is formed into a spherical shape divided into approximately four equal parts. If the inner wall of the cavity 51 is flush, it is less likely to get caught when a molded product including the guide portions 52 is removed from the mold using the plane P as the mold parting plane.

[0049] Fig. 12 is a bottom view showing the second shape of guide member 5 according to the first embodiment. Deformation of guide member 5 will be described below in comparison with the first shape shown in Fig. 6. Guide member 5 is configured to be deformable between a first shape in contact with cylindrical surface 22 and a second shape away from cylindrical surface 22.

[0050] In the illustrated example, the pair of first arm 50L and second arm 50R are elastically deformable, and when the pressing member 58 presses the first arm 50L and the second arm 50R against the biasing force, the guide member 5 is deformed from the first shape shown in Fig. 6 to the second shape shown in Fig. 12. Conversely, when the pressing member 58 moves away from the first arm 50L and the second arm 50R, the restoring forces of the first arm 50L and the second arm 50R deform the guide member 5 from the second shape to the first shape.

[0051] More specifically, the pressing member 58 moves along a first axis V that is perpendicular to the rotation axis O. A direction that is perpendicular to the first axis V and parallel to the XY plane is called a second direction W. The first arm 50L has a first inclined surface 54L that faces the pressing member 58, and the second arm 50R has a second inclined surface 54R that faces the pressing member 58.

[0052] 6, the first inclined surface 54L and the second inclined surface 54R are inclined in the second direction W so as to approach the first axis V as they approach the rotation axis O. When the pressing member 58 is brought closer to the rotation axis O, the pressing member 58 presses the first inclined surface 54L and the second inclined surface 54R against the biasing force, causing the first arm 50L and the second arm 50R to move away from the cylindrical surface 22 and assume the second shape shown in FIG.

[0053] The pressing member 58 is, for example, a bolt, which presses against the first inclined surface 54L and the second inclined surface 54R when the screw is tightened, and moves away from the first inclined surface 54L and the second inclined surface 54R when the screw is loosened. In order to press against the first inclined surface 54L and the second inclined surface 54R evenly, it is preferable that the tip of the pressing member 58 is tapered.

[0054] FIG. 13 is a flowchart illustrating a method for installing a rotation sensor device. As shown in FIG. 13, the method for installing the rotation sensor device 3 includes the following steps: Step S1: Fix the magnetic field generating unit 2 to the tip of a rotating body such as the output shaft 120; Step S2: Place the rotation sensor device 3 over the magnetic field generating unit 2 and bring the guide member 5 in the first shape into contact with the cylindrical surface 22; Step S3: Fix the rotation sensor device 3 to the housing 110, which rotatably supports the rotating body such as the output shaft 120, with its movement restricted by the contact between the cylindrical surface 22 and the guide member 5; Step S4: Deform the guide member 5 from the first shape to the second shape. This separates the guide member 5 from the cylindrical surface 22, thereby reducing power loss due to frictional resistance.

[0055] 14 and 15 are bottom views showing the first and second shapes of the guide member 5 according to the second embodiment. The guide member 5 according to the second embodiment further includes a connecting member that connects the first arm 50L and the second arm 50R in the first shape. When the guide member 5 is transformed from the first shape shown in FIG. 14 to the second shape shown in FIG. 15, the pressing member 58 cuts the connecting portion 50C.

[0056] In the illustrated example, the first arm 50L has a first inclined surface 54L, and the second arm 50R has a second inclined surface 54R. When in the first shape shown in Fig. 14, the first inclined surface 54L and the second inclined surface 54R are inclined in the second direction W so as to approach the first axis V as they approach the rotation axis O. When the pressing member 58 is brought closer to the rotation axis O, the pressing member 58 presses the first inclined surface 54L and the second inclined surface 54R against the biasing force, and the first arm 50L and the second arm 50R move away from the cylindrical surface 22 and assume the second shape shown in Fig. 15.

[0057] 16 and 17 are bottom views showing the first and second shapes of a guide member 5 according to the third embodiment. The guide member 5 according to the third embodiment is equipped with a linear motion mechanism that converts rotational motion into linear motion of a pressing member 58. In the example shown, the linear motion mechanism is a combination of a pressing member 58 that is a nut and a screw shaft 59. The linear motion mechanism is not particularly limited, and may be a ball screw, a rack and pinion, or another type.

[0058] The first arm 50L has a first inclined surface 54L facing the pressing member 58, is elastically deformable, and rotates around the first hinge 53L. The second arm 50R has a second inclined surface 54R facing the pressing member 58, is elastically deformable, and rotates around the second hinge 53R. In the example shown, the first hinge 53L and the second hinge 53R are bendable resin hinges that are thinner than the other parts.

[0059] In the illustrated example, a first axis V perpendicular to the rotation axis O is the center of the screw shaft 59. In the first shape shown in FIG. 16 , the first inclined surface 54L and the second inclined surface 54R are inclined so as to move away from the first axis V in the second direction W as they approach the rotation axis O.

[0060] 16, when the pressing member 58 is moved away from the rotation axis O, the pressing member 58 presses the first inclined surface 54L and the second inclined surface 54R, causing the first arm 50L and the second arm 50R to move away from the cylindrical surface 22 and deform into the second shape shown in FIG. 17. When the pressing member 58 is moved closer to the rotation axis O in the second shape shown in FIG. 17, the restoring force of the first arm 50L and the second arm 50R deforms the first arm 50L and the second arm 50R so as to sandwich the cylindrical surface 22, thereby achieving the first shape. Because the rotation sensor device 1 can be returned to the first shape, it can be removed and reused.

[0061] 18 is a side view showing a first shape of the guide member 5 according to the fourth embodiment. In the illustrated example, the guide member 5 moves in the direction perpendicular to the surface Z. The guide member 5 of the first shape is arranged so as to overlap with the cylindrical surface 22 in the radial direction U perpendicular to the rotation axis O. The guide member 5 of the second shape moves toward the substrate 4 and is arranged so as not to overlap with the cylindrical surface 22 in the radial direction U.

[0062] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those illustrated and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined with each other.

[0063] For example, in each embodiment, a guide portion may be provided on the cylindrical surface 22 of the magnetic field generating unit 2 instead of the guide member 5. For example, contrary to the first and second embodiments, the first arm 50L and the second arm 50R may be deformed from the second shape to the first shape against a biasing force, and then the first arm 50L and the second arm 50R may be deformed from the first shape to the second shape by a restoring force. The first arm 50L and the second arm 50R are not limited to being elastically deformable. For example, the first arm 50L may be configured to rotate freely around the first hinge 53L without elastic deformation, and a stopper may be provided to stop the rotation of the first arm 50L at a position where the guide member 5 assumes the first shape or the second shape. The second arm 50R may be configured similarly to the first arm 50L. [Explanation of symbols]

[0064] 1...Rotation sensor unit, 2...Magnetic field generating portion, 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 chip, 42...Functional film, 42A...Magnetic detection element array, 42E...Magnetic detection element, 42W...Wiring layer, 43...ASIC, 44...Connector, 5...Guide member, 50C...Connection portion, 50L...First arm, 50R...Second arm, 51...Cavity, 52... Guide portion, 53L...first hinge, 53R...second hinge, 54L...first inclined surface, 54R...second inclined surface, 58...pressure member, 59...screw shaft, 100...electric motor, 110...casing, 120...output shaft, 200...autonomously traveling transport robot, 210...control unit, 220...power supply unit, 230...wheel, G...gap, H...magnetic field, L...generator, N...normal, O...rotation axis, P...plane, R1...first distance, R2...second distance, U...radial direction, V...first axis, W...second direction, X, Y...in-plane direction, Z...direction perpendicular to the plane, θ...rotation angle.

Claims

1. A rotation sensor device for detecting a rotation state of a magnetic field generating unit that rotates around a rotation axis, the magnetic field generating unit generates a magnetic field symmetrical with respect to the rotation axis and has a cylindrical surface centered on the rotation axis, The rotation sensor device a magnetic detection element that detects a magnetic field generated by the magnetic field generating unit; a guide member that is deformable into a first shape in contact with the cylindrical surface and a second shape that is spaced apart from the cylindrical surface, Rotation sensor device.

2. The guide member is a first arm and a second arm that are elastically deformable; a pressing member that presses the first arm and the second arm, When the pressing member presses the first arm and the second arm against the biasing force, the guide member is deformed from the first shape to the second shape or from the second shape to the first shape, When the pressing member moves away from the first arm and the second arm, the guide member is deformed from the second shape to the first shape or from the first shape to the second shape by a restoring force of the first arm and the second arm. The rotation sensor device according to claim 1 .

3. the guide member further includes a connecting member that connects the first arm and the second arm in the first shape, When the connector is transformed from the first shape to the second shape, the pressing member cuts the connecting member. The rotation sensor device according to claim 2 .

4. The guide member is a pressing member that moves along a first axis perpendicular to the rotation axis; a first arm having a first inclined surface facing the pressing member and capable of elastic deformation; a second arm having a second inclined surface facing the pressing member and capable of elastic deformation, In the first shape, the first inclined surface and the second inclined surface are inclined so as to approach the first axis as they approach the rotation axis, When the pressing member is brought closer to the rotation shaft, the pressing member presses the first inclined surface and the second inclined surface against the biasing force, causing the first arm and the second arm to move away from the cylindrical surface and assume a second shape. The rotation sensor device according to claim 1 .

5. The guide member is a pressing member that moves along a first axis perpendicular to the rotation axis; a first arm having a first inclined surface facing the pressing member and capable of elastic deformation; a second arm having a second inclined surface facing the pressing member and capable of elastic deformation, In the first shape, the first inclined surface and the second inclined surface are inclined so as to move away from the first axis as they approach the rotation axis, When the pressing member is moved away from the rotation shaft, the pressing member presses the first inclined surface and the second inclined surface against the biasing force, whereby the first arm and the second arm are separated from the cylindrical surface and deformed into the second shape. The rotation sensor device according to claim 1 .

6. Further provided with a linear motion mechanism that converts rotational motion into linear motion of the pressing member, The rotation sensor device according to claim 5 .

7. The rotation state is a rotation angle of the magnetic field generating unit. The rotation sensor device according to claim 1 .

8. a magnetic field generating unit that rotates around a rotation axis; a rotation sensor device for detecting a 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 a cylindrical surface centered on the rotation axis, The rotation sensor device a magnetic detection element that detects a magnetic field generated by the magnetic field generating unit; a guide member that is deformable into a first shape in contact with the cylindrical surface and a second shape that is spaced apart from the cylindrical surface, Rotation sensor unit.

9. A rotation sensor unit according to claim 8, a housing in which the rotation sensor device is mounted; An output shaft to which the magnetic field generating unit is attached, Electric motor.

10. A motor comprising the electric motor according to claim 9. Rotation mechanism.

11. A method for mounting a rotation sensor device that detects the rotation state of a magnetic field generating unit that rotates around a rotation axis, comprising: the magnetic field generating unit generates a magnetic field symmetrical with respect to the rotation axis and has a cylindrical surface centered on the rotation axis, The rotation sensor device a magnetic detection element that detects a magnetic field generated by the magnetic field generating unit; a guide member that is deformable into a first shape in contact with the cylindrical surface and a second shape that is spaced apart from the cylindrical surface, The method comprises: fixing the magnetic field generating unit to a tip of a rotating body; placing the rotation sensor device over the magnetic field generating unit and bringing the first-shaped guide member into contact with the cylindrical surface; The rotation sensor device is fixed to a housing that rotatably supports the rotating body, and the movement of the rotation sensor device is restricted by contact between the cylindrical surface and the guide member; and deforming the guide member from the first shape to the second shape. A method for installing a rotation sensor device.

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