Rotation angle detection device

Abstract

A rotation angle detection device (1) comprises a magnetic circuit (30) and a magnetic detection unit (50). The magnetic circuit (30) has a first magnet (31), a second magnet (32), a first yoke (41), and a second yoke (42), and is fixed to rotating bodies (20, 21). The magnetic detection unit (50) is fixed to a support body (10) such that a magnetic detection element (52) is positioned on the axial center (CL) of the rotation of the rotating bodies. A direction in which a virtual line connecting the center of the first magnet (31) and the center of the second magnet (32) extends is defined as a first direction, and a direction orthogonal to the first direction and to a direction in which the axial center (CL) extends is defined as a second direction. The first yoke (41) and the second yoke (42) are disposed so as to face each other in the second direction with the axial center (CL) therebetween. The inter-first-magnet distance (D1) and the inter-second-magnet distance (D2) are both greater than or equal to the inter-yoke-inner-wall distance (D3).

Description

Rotation Angle Detection Device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2023-172949, filed on October 4, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a rotation angle detection device.

[0003] The rotation angle detection device described in Patent Document 1 is used, for example, in an electronic throttle of an automobile. The electronic throttle has a configuration in which a shaft member fixed to a throttle valve is rotatable relative to a housing. The rotation angle detection device includes a magnetic circuit provided on the shaft member and a magnetic detection unit provided on the housing so as to be positioned on the axis of rotation of the shaft member, and detects the rotation angle of the shaft member relative to the housing. The magnetic circuit provided in the rotation angle detection device has two magnets and two yokes. The two magnets are arranged opposite each other across the axis of rotation of the shaft member and are magnetized in the same direction. One of the two yokes connects the north poles of the two magnets, and the other yoke connects the south poles of the two magnets.

[0004] One yoke has a first concave curved surface and a second concave curved surface near each of the two magnets, extending from the magnet side toward the center and away from an imaginary line connecting the centers of the two magnets. One yoke also has a parallel portion formed parallel to the imaginary line in the center between the first and second concave curved surfaces. The other yoke also has a third concave curved surface and a fourth concave curved surface near each of the two magnets, extending from the magnet side toward the center and away from the imaginary line. The other yoke also has a parallel portion formed parallel to the imaginary line in the center between the third and fourth concave curved surfaces. With this configuration, when the magnetic circuit rotates together with the shaft member, the direction of the magnetic field passing through the magnetic detection unit changes, and the magnetic detection unit outputs an electrical signal corresponding to the direction of the magnetic field.

[0005] Patent No. 5818104

[0006] However, the two yokes in the rotation angle detector described in Patent Document 1 have first to fourth concave curved surfaces near the magnet. Here, the magnetic field emitted into space from the surface of the yoke facing the axis (hereinafter referred to as the "inner wall surface of the yoke") is emitted perpendicular to the inner wall surface of the yoke. Therefore, some of the magnetic field emitted from the first to fourth concave curved surfaces of the yoke passes near the axis in the inner region of the magnetic circuit. Therefore, in the inner region of the magnetic circuit, including the axis and its vicinity, the parallel magnetic field range where only parallel components of the magnetic field exist without being affected by the magnetic field emitted from the first to fourth concave curved surfaces is small. Therefore, in this rotation angle detector, if the housing and the shaft member are misaligned due to clearance or other factors caused by the rotational movement of the housing and the shaft member, and the magnetic detection unit moves from its position on the axis to outside the parallel magnetic field range, the rotation angle detection accuracy may be reduced.

[0007] An object of the present disclosure is to provide a rotation angle detection device capable of improving the detection accuracy of a rotation angle, and a brake pedal device including the same.

[0008] According to one aspect of the present disclosure, a rotation angle detection device for detecting a rotation angle of a rotor rotatably provided with respect to a support comprises: a magnetic circuit having a first magnet and a second magnet arranged opposite each other across an axis of rotation of the rotor and having the same magnetization direction, and a first yoke and a second yoke connecting the same poles of the first magnet and the second magnet, and fixed to the rotor; and a magnetic detection unit having a magnetic detection element that outputs an electric signal according to the magnetic field in an area inside the magnetic circuit, and fixed to the support so that the magnetic detection element is located on the axis, wherein the direction in which an imaginary line connecting the center of the first magnet and the center of the second magnet extends is defined as a first direction, and the direction in which the axis extends and a direction perpendicular to the first direction are defined as a second direction, the first yoke and the second yoke are arranged opposite each other in the second direction across the axis, Both "the distance between the portion of the first yoke facing the north pole of the first magnet and the portion of the second yoke facing the south pole of the first magnet" and "the distance between the portion of the first yoke facing the north pole of the second magnet and the portion of the second yoke facing the south pole of the second magnet" are greater than or equal to "the distance between the surface of the first yoke facing the second yoke between the first magnet and the second magnet and the surface of the second yoke facing the first yoke between the first magnet and the second magnet."

[0009] In this disclosure, "same" means substantially the same in light of the gist of this disclosure, and includes not only complete identity but also slight non-identity due to, for example, manufacturing tolerances, etc. In the following description, the first yoke and second yoke may be collectively referred to simply as the "yoke," and the first magnet and second magnet may be collectively referred to simply as the "magnet."

[0010] According to the above configuration, the magnetic field emitted from the portion of the yoke near the magnet and passing through the inner region of the magnetic circuit does not affect the magnetic field emitted from the portion of the yoke other than the portion near the magnet (i.e., the central portion of the yoke) and passing through the inner region of the magnetic circuit. This allows for a larger range of parallel magnetic fields in the inner region of the magnetic circuit, including the axis and its vicinity. Therefore, even if the magnetic detection unit moves from the axis due to a misalignment between the support and the rotor, the change in the direction of the magnetic field passing through the magnetic detection unit due to the movement is suppressed. Therefore, the rotation angle detection device can improve the detection accuracy of the rotation angle of the rotor relative to the support.

[0011] According to another aspect of the present disclosure, a brake pedal device mounted on a vehicle includes a support fixed to a vehicle body, an axial member provided on the support, a brake pedal rotatable within a predetermined angle range around the axis of the axial member relative to the support, and a rotation angle detection device described in one aspect of the present disclosure that detects the rotation angle of the axial member as a rotating body or the brake pedal as a rotating body relative to the support.

[0012] According to this, if the brake pedal device erroneously detects a large brake pedal depression angle when the driver applies a small brake pedal force, the driver may experience unintended sudden deceleration. Furthermore, if the brake pedal device erroneously detects a large brake pedal depression angle when the driver does not apply a brake pedal force, the vehicle may experience unintended braking while traveling. Therefore, a rotation angle detection device used in a brake pedal device is required to detect the rotation angle of a rotating body relative to a support with high accuracy. Meanwhile, a brake pedal device requires a clearance between the support and the rotating body to rotate the shaft member or brake pedal relative to the support, which can cause misalignment (i.e., axial misalignment) between the support and the rotating body. For these reasons, a rotation angle detection device used in a brake pedal device is required to detect the angle with high accuracy even when the support and the rotating body are misaligned. To meet these requirements specific to a brake pedal device, a rotation angle detection device can detect the rotation angle of a rotating body relative to the support with high accuracy, even when the magnetic detection unit moves off-axis due to misalignment between the support and the rotating body.

[0013] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below.

[0014] FIG. 1 is a schematic configuration diagram of a brake-by-wire system including a brake pedal device in which a rotation angle detection device according to a first embodiment is used. FIG. 2 is a cross-sectional view perpendicular to the axis of a shaft member in the brake pedal device. FIG. 3 is a cross-sectional view taken along line III-III in FIGS. 1 and 2. FIG. 4 is a configuration diagram of a rotation angle detection device according to a first embodiment, taken along line IV-IV in FIG. 3. FIG. 5 is an explanatory diagram for explaining single-axis detection in a rotation angle detection device. FIG. 6 is an explanatory diagram for explaining two-axis detection in a rotation angle detection device. FIG. 7 is a configuration diagram of a rotation angle detection device according to a second embodiment. FIG. 8 is a configuration diagram of a rotation angle detection device according to a third embodiment. FIG. 9 is a configuration diagram of a rotation angle detection device according to a fourth embodiment. FIG. 10 is a configuration diagram of a rotation angle detection device of a comparative example.

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0016] (First embodiment) A first embodiment will be described. As shown in Fig. 1, a rotation angle detection device 1 of the first embodiment is used in a brake pedal device 2 mounted on a vehicle. The brake pedal device 2 constitutes a part of a brake-by-wire system 3 that brakes the vehicle. The brake-by-wire system 3 is a system in which a brake mechanism 5 brakes the vehicle under drive control of an electronic control unit (hereinafter referred to as "ECU 4") mounted on the vehicle. ECU is an abbreviation for Electronic Control Unit.

[0017] <Configuration of Brake Pedal Device and Brake-by-Wire System> First, the schematic configuration of the brake pedal device 2 and the brake-by-wire system 3 will be described.

[0018] As shown in FIGS. 1 to 3, the brake pedal device 2 includes a housing 10 as a support, a shaft member 20 as a rotating body, a brake pedal 21, and a rotation angle detection device 1.

[0019] The housing 10 is fixed directly to the vehicle body with bolts or the like (not shown), or indirectly to the vehicle body via a base member or the like (not shown). Specifically, the housing 10 is fixed to the dash panel or floor inside the vehicle. As shown in Fig. 3, bearings 11 and 12 are provided inside the housing 10 to rotatably support the shaft member 20. The bearings 11 and 12 may be, for example, rolling bearings or plain bearings.

[0020] The shaft member 20 is formed in a rod shape and is supported by bearings 11 and 12 provided within the housing 10. The shaft member 20 is provided to be rotatable within a predetermined angular range with its own axis CL as the center of rotation relative to the housing 10. Slight clearances C1 and C2 are provided between the shaft member 20 and the bearings 11 and 12 to allow the shaft member 20 to rotate.

[0021] As shown in Fig. 2, the brake pedal 21 has a pedal arm 22 and a pedal pad 23. One end of the pedal arm 22 is fixed to the shaft member 20, and the other end is provided with the pedal pad 23. The pedal pad 23 is the part that is stepped on by the driver's foot. When the driver depresses the brake pedal 21, the brake pedal 21 rotates in the forward and reverse directions within a predetermined angular range around the axis center CL of the shaft member 20. In this disclosure, "rotation" also includes "swinging."

[0022] The reaction force generating mechanism 24 is configured by, for example, a spring, an actuator, etc. The reaction force generating mechanism 24 is a mechanism that generates a reaction force against the driver's depressing force applied to the brake pedal 21. By including the reaction force generating mechanism 24, the brake pedal device 2 can obtain a reaction force similar to that obtained when the brake pedal 21 is connected to a master cylinder (i.e., when a reaction force is obtained by hydraulic pressure) even if the mechanical connection between the brake pedal 21 and a conventional master cylinder is eliminated.

[0023] 1, the rotation angle detection device 1 detects the rotation angle of a shaft member 20 and a brake pedal 21, which serve as rotating bodies, relative to a housing 10, which serves as a support body. An electrical signal output from the rotation angle detection device 1 is transmitted to an ECU 4.

[0024] The ECU 4 is composed of a microcomputer including a processor that performs control processing and arithmetic processing, a memory unit such as ROM and RAM that stores programs and data, and peripheral circuits. The memory unit is composed of a non-transient physical storage medium. The ECU 4 performs various control processing and arithmetic processing based on the programs stored in the memory unit and controls the operation of each device connected to its output port. Specifically, the ECU 4 detects the rotation angle of the shaft member 20 and the brake pedal 21, i.e., the operation amount of the brake pedal 21, based on the electrical signal transmitted from the rotation angle detection device 1, and controls the operation of the brake mechanism 5.

[0025] Various mechanisms can be employed as the brake mechanism 5. For example, the brake mechanism 5 may be an electric brake in which an electric motor is driven by a command from the ECU 4 to press brake pads against disc brake rotors, thereby braking each wheel. Alternatively, the brake mechanism 5 may be configured to increase the hydraulic pressure of the brake fluid by operating a master cylinder or a hydraulic pump, thereby driving wheel cylinders arranged on each wheel and operating the brake pads.

[0026] <Configuration of Rotation Angle Detection Device> Next, the rotation angle detection device 1 will be described.

[0027] As shown in FIGS. 3 and 4 , the rotation angle detection device 1 includes a magnetic circuit 30, a magnetic detection unit 50, and other components. The magnetic circuit 30 includes a first magnet 31, a second magnet 32, a first yoke 41, and a second yoke 42, and is formed in a rectangular cylindrical shape. Therefore, when viewed in the direction of the axis CL, the inner wall surface of the magnetic circuit 30 is formed in a square shape. As shown in FIG. 3 , the first magnet 31, the second magnet 32, the first yoke 41, and the second yoke 42 are molded in a resin body 33 and fixed to the end of the shaft member 20 by bolts (not shown). Therefore, the positional relationship between the magnetic circuit 30 and the axis CL of the shaft member 20 is fixed. Note that in FIGS. 4 to 6 and FIGS. 7 to 10 , which will be referred to in the following embodiments and comparative examples, the resin body 33 that molds the magnetic circuit 30 and the hatching indicating the cross sections of each component are omitted.

[0028] On the other hand, as shown in FIG. 3 , the magnetic detection unit 50 has a resin part 51 and a magnetic detection element 52. The magnetic detection element 52 is resin-molded by the resin part 51. The magnetic detection element 52 outputs an electric signal corresponding to the magnetic field in the region inside the magnetic circuit 30. More specifically, the magnetic detection element 52 outputs an electric signal corresponding to the magnitude of the magnetic flux density passing through its magnetic sensing surface in the magnetic field in the region inside the magnetic circuit 30. For example, a Hall element or a magnetoresistive element can be used as the magnetic detection element 52. The Hall element or the magnetoresistive element can be incorporated into an integrated circuit (hereinafter referred to as "IC"). IC stands for integrated circuit.

[0029] The resin part 51 of the magnetic detection unit 50 is fixed to the housing 10 so that the magnetic detection element 52 is located on the axis CL. Various methods can be used to fix the resin part 51 of the magnetic detection unit 50 to the housing 10, such as bolting, press-fitting, fitting, or snap-fitting. Note that "so that the magnetic detection element 52 is located on the axis CL" means that, in design (i.e., theoretically), the magnetic detection element 52 is positioned on the axis CL of the shaft member 20. In reality, the magnetic detection element 52 may deviate from its position on the axis CL of the shaft member 20 due to clearances C1 and C2 between the shaft member 20 and the bearings 11 and 12, manufacturing tolerances, and the like.

[0030] 4 shows a state in which the magnetic detection element 52 of the magnetic detection unit 50 is positioned on the axis CL. However, as described above, in reality, slight clearances C1 and C2 are provided between the shaft member 20 and the bearings 11 and 12 to allow for rotational movement of the shaft member 20. Therefore, while the brake pedal device 2 is in use, the magnetic detection unit 50 fixed to the housing 10 and the magnetic circuit 30 fixed to the shaft member 20 may become misaligned. Therefore, the magnetic detection element 52 of the magnetic detection unit 50 may move from the axis CL within the area inside the magnetic circuit 30.

[0031] In the following description, as shown in FIG. 4 , the direction of an imaginary line connecting the center of the first magnet 31 and the center of the second magnet 32 ​​is referred to as the “first direction.” The direction of the axis CL and the direction perpendicular to the first direction are referred to as the “second direction.” The first magnet 31 side relative to the axis CL is referred to as the “one side of the first direction,” the second magnet 32 ​​side relative to the axis CL is referred to as the “other side of the first direction,” the first yoke 41 side relative to the axis CL is referred to as the “one side of the second direction,” and the second yoke 42 side relative to the axis CL is referred to as the “other side of the second direction.” Furthermore, in the following description, a predetermined imaginary plane that includes the axis CL and is parallel to the second direction is referred to as the “second imaginary plane S2.” Another imaginary plane that includes the axis CL and is parallel to the first direction is referred to as the “first imaginary plane S1.”

[0032] The first magnet 31 and the second magnet 32 ​​are arranged opposite each other in the first direction across the axis CL of the shaft member 20. "Opposite arrangement" refers to arrangements that face each other. The first magnet 31 and the second magnet 32 ​​are both permanent magnets, and are formed in a rectangular parallelepiped or cylindrical shape. The first magnet 31 and the second magnet 32 ​​are both arranged so that their magnetization directions are parallel to the second direction and in the same direction. Specifically, the first magnet 31 and the second magnet 32 ​​are arranged so that their north poles face one side of the second direction and their south poles face the other side of the second direction.

[0033] The first yoke 41 and the second yoke 42 are disposed opposite each other in the second direction across the axis CL of the shaft member 20. Both the first yoke 41 and the second yoke 42 are made of magnetic material and are formed in a flat plate or rectangular parallelepiped shape. The first yoke 41 and the second yoke 42 connect the same poles of the first magnet 31 and the second magnet 32. Specifically, the first yoke 41 connects the north pole of the first magnet 31 and the north pole of the second magnet 32. The second yoke 42 connects the south pole of the first magnet 31 and the south pole of the second magnet 32.

[0034] The first yoke 41 and the second yoke 42 are arranged parallel to the first direction. More specifically, the surface of the first yoke 41 facing the second yoke 42 between the first magnet 31 and the second magnet 32 ​​(hereinafter referred to as the "first yoke inner wall surface 413") is planar and parallel to the first direction, extending from the first magnet 31 to the second magnet 32. In addition, the surface of the second yoke 42 facing the first yoke 41 between the first magnet 31 and the second magnet 32 ​​(hereinafter referred to as the "second yoke inner wall surface 423") is also planar and parallel to the first direction, extending from the first magnet 31 to the second magnet 32.

[0035] In this disclosure, "parallel" refers to being substantially parallel in light of the intent of this disclosure, and includes not only perfect parallelism but also slight non-parallelism due to, for example, manufacturing tolerances, etc. In this disclosure, "planar" refers to being substantially flat in light of the intent of this disclosure, and includes not only perfect flatness but also slight non-flatness due to, for example, manufacturing tolerances, etc.

[0036] Here, the distance between a portion 411 of the first yoke 41 facing the north pole of the first magnet 31 and a portion 421 of the second yoke 42 facing the south pole of the first magnet 31 is referred to as the first inter-magnet distance D1. The distance between a portion 412 of the first yoke 41 facing the north pole of the second magnet 32 ​​and a portion 422 of the second yoke 42 facing the south pole of the second magnet 32 ​​is referred to as the second inter-magnet distance D2. In addition, the distance between the first yoke inner wall surface 413 and the second yoke inner wall surface 423 is referred to as the yoke inner wall distance D3.

[0037] In the first embodiment, the distance D1 between the first magnets, the distance D2 between the second magnets, and the distance D3 between the yoke inner walls are the same. Note that, in this disclosure, "same" means substantially the same in light of the gist of this disclosure, and includes not only complete sameness but also slight non-identity due to, for example, manufacturing tolerances.

[0038] Furthermore, the distance D4 between the first magnet 31 and the second magnet 32 ​​is greater than the distance D3 between the inner walls of the yoke.

[0039] 4, for ease of explanation, the boundary between a portion 411 of the first yoke 41 facing the N pole of the first magnet 31 and a first yoke inner wall surface 413 is indicated by an arrow 414. Furthermore, the boundary between a portion 412 of the first yoke 41 facing the N pole of the second magnet 32 ​​and the first yoke inner wall surface 413 is indicated by an arrow 415. However, the portion 411 of the first yoke 41 facing the N pole of the first magnet 31, the first yoke inner wall surface 413, and the portion 412 of the first yoke 41 facing the N pole of the second magnet 32 ​​are formed by a continuous plane.

[0040] 4, for ease of explanation, the boundary between a portion 421 of the second yoke 42 facing the south pole of the first magnet 31 and a second yoke inner wall surface 423 is indicated by an arrow 424. The boundary between a portion 422 of the second yoke 42 facing the south pole of the second magnet 32 ​​and the second yoke inner wall surface 423 is indicated by an arrow 425. However, the portion 421 of the second yoke 42 facing the south pole of the first magnet 31, the second yoke inner wall surface 423, and the portion 422 of the second yoke 42 facing the south pole of the second magnet 32 ​​are formed by a continuous plane.

[0041] The magnetic circuit 30 is symmetrical with respect to the second imaginary plane S2. The magnetic circuit 30 is also symmetrical with respect to the first imaginary plane S1. In this disclosure, "symmetrical" refers to being substantially symmetrical in light of the gist of the disclosure, and includes not only perfect symmetry but also slight asymmetry due to, for example, manufacturing tolerances.

[0042] Specifically, the magnetic circuit 30 being symmetrical with respect to the second imaginary plane S2 means that the first magnet 31 and the second magnet 32 ​​have the same shape, size, material properties, etc., and the distance between the first magnet 31 and the second imaginary plane S2 is the same as the distance between the second magnet 32 ​​and the second imaginary plane S2. Furthermore, the first yoke 41 has the same shape, size, material properties, etc., on one side and the other side of the second imaginary plane S2. Similarly, the second yoke 42 has the same shape, size, material properties, etc., on one side and the other side of the second imaginary plane S2.

[0043] The magnetic circuit 30 being symmetrical with respect to the first imaginary plane S1 means that the first yoke 41 and the second yoke 42 have the same shape, size, material properties, etc., and the distance between the first yoke 41 and the first imaginary plane S1 and the distance between the second yoke 42 and the first imaginary plane S1 are the same. Furthermore, the first magnet 31 has the same shape, size, material properties, etc., on both sides of the first imaginary plane S1. Similarly, the second magnet 32 ​​has the same shape, size, material properties, etc., on both sides of the first imaginary plane S1.

[0044] Generally, the magnetic field emitted from the inner wall surface of the yoke into space is emitted perpendicular to the inner wall surface of the yoke. In FIG. 4 , the magnetic field emitted from the first yoke inner wall surface 413, passing through the inner region of the magnetic circuit 30, and heading toward the second yoke inner wall surface 423 (i.e., the magnetic field in the inner region of the magnetic circuit 30) is indicated by multiple dashed arrows M1. Due to the configuration of the magnetic circuit 30 described above, the inner region of the magnetic circuit 30 is subject to a substantially parallel magnetic field. Therefore, even if the magnetic detection unit 50 moves from the axis CL during use of the brake pedal device 2, the direction of the magnetic field passing through the magnetic detection unit 50 is prevented from changing due to the movement. Therefore, the rotation angle detection device 1 can improve the detection accuracy of the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10.

[0045] <Method for detecting rotation angle by rotation angle detection device> Next, one-axis detection and two-axis detection will be described as examples of a method for detecting a rotation angle by the rotation angle detection device 1. One-axis detection is also called scalar detection. Two-axis detection is also called vector detection.

[0046] First, one-axis detection will be described with reference to FIG. 5 . FIG. 5 shows a state in which the magnetic circuit 30 has rotated a predetermined angle clockwise relative to the magnetic detection unit 50 from the state shown in FIG. 4 . In FIG. 5 , the angle by which the magnetic circuit 30 has rotated from the state shown in FIG. 4 is indicated by θ1. When the rotation angle detection device 1 performs one-axis detection, as shown in FIG. 5 , the magnetic detection element 52 of the magnetic detection unit 50 has at least one magnetically sensitive surface 53. The magnetic detection unit 50 outputs a signal corresponding to the magnetic flux density passing through the magnetically sensitive surface 53, which is oriented in a predetermined direction. When the direction of the magnetic field passing through the magnetically sensitive surface 53 of the magnetic detection element 52 changes as the magnetic circuit 30 rotates, the magnetic flux density passing through the magnetically sensitive surface 53 changes accordingly. Note that, for the sake of explanation, in FIG. 5 , the direction and magnitude of the magnetic field passing through the magnetic detection element 52 are indicated by arrow M2, and the magnitude of the signal output by the magnetic detection element 52 corresponding to the magnetic flux density passing through the magnetically sensitive surface 53 is indicated by arrow V1. The IC or ECU 4 of the magnetic detection unit 50 stores in advance the relationship between the magnitude of the signal output by the magnetic detection element 52 and the direction of the magnetic field passing through the magnetic detection element 52, i.e., the rotation angle θ1 of the magnetic circuit 30. Therefore, the IC or ECU 4 of the magnetic detection unit 50 can calculate the direction of the magnetic field passing through the magnetic detection element 52, i.e., the rotation angle θ1 of the magnetic circuit 30, based on the magnitude of the signal output in accordance with the magnetic flux density passing through the magnetic sensing surface 53. This allows the IC or ECU 4 of the magnetic detection unit 50 to detect the rotation angles of the shaft member 20 and the brake pedal 21 relative to the housing 10.

[0047] Next, two-axis detection will be described. FIG. 6 also shows a state in which the magnetic circuit 30 has rotated a predetermined angle clockwise relative to the magnetic detection unit 50 from the state shown in FIG. 4 . In FIG. 6 , the angle by which the magnetic circuit 30 has rotated from the state shown in FIG. 4 is indicated by θ2. As shown in FIG. 6 , when the rotation angle detection device 1 performs two-axis detection, the magnetic detection element 52 has multiple magnetically sensitive surfaces 54, 55. Of the multiple magnetically sensitive surfaces 54, 55, the first magnetically sensitive surface 54 and the second magnetically sensitive surface 55 are arranged in different orientations (specifically, perpendicular orientations). Therefore, with respect to the orientation of the magnetic field passing through the magnetic detection element 52 as the magnetic circuit 30 rotates, the magnetic flux density passing through the first magnetically sensitive surface 54 differs from the magnetic flux density passing through the second magnetically sensitive surface 55. Therefore, the magnetic detection element 52 outputs signals of different magnitudes based on the magnetic flux density passing through the first magnetically sensitive surface 54 and the magnetic flux density passing through the second magnetically sensitive surface 55.

[0048] In FIG. 6 , for the sake of explanation, the direction and magnitude of the magnetic field passing through the magnetic detection element 52 are indicated by arrow M3. Furthermore, the magnitude of the signal output based on the magnetic flux density passing through the first magnetic sensing surface 54 is indicated by arrow V2, and the magnitude of the signal output based on the magnetic flux density passing through the second magnetic sensing surface 55 is indicated by arrow V3. The IC or ECU 4 of the magnetic detection unit 50 can calculate the direction of the magnetic field passing through the magnetic detection unit 50 by arc tangent from the magnitude of the signal output based on the magnetic flux density passing through the first magnetic sensing surface 54 and the magnitude of the signal output based on the magnetic flux density passing through the second magnetic sensing surface 55. That is, the IC or ECU 4 of the magnetic detection unit 50 can calculate the rotation angle θ2 of the magnetic circuit 30. Therefore, the IC or ECU 4 of the magnetic detection unit 50 can detect the rotation angles of the shaft member 20 and the brake pedal 21 relative to the housing 10.

[0049] In addition, the magnetic field strength in the inner region of the magnetic circuit 30 becomes stronger as it approaches the first yoke 41 and the second yoke 42, relative to the intermediate position between the first yoke 41 and the second yoke 42 (i.e., near the axis CL). Therefore, with the above-described one-axis detection, if the magnetic detection unit 50 moves in the second direction from the axis CL, the detection accuracy of the rotation angle may decrease. In contrast, with two-axis detection, the rotation angle can be detected accurately even if the magnetic detection unit 50 moves to one side or the other in the second direction from the axis CL due to clearances C1, C2 between the shaft member 20 and the bearings 11, 12, etc.

[0050] <Rotation Angle Detection Device of Comparative Example> Here, a rotation angle detection device 100 of a comparative example will be described for comparison with the rotation angle detection device 1 of the first embodiment described above.

[0051] 10 , the rotation angle detection device 100 of the comparative example also includes a magnetic circuit 500 and a magnetic detection unit 600. The magnetic circuit 500 includes a first magnet 510, a second magnet 520, a first yoke 530, and a second yoke 540. The first yoke 530 includes a first concave curved surface 531 extending from the first magnet 510 side toward the center and away from the first imaginary plane S1, and a second concave curved surface 532 extending from the second magnet 520 side toward the center and away from the first imaginary plane S1. The first yoke 530 also includes a first yoke-side parallel portion 533 formed parallel to the first imaginary plane S1 in the center between the first concave curved surface 531 and the second concave curved surface 532.

[0052] The second yoke 540 also has a third concave curved surface 541 extending from the first magnet 510 side toward the center so as to move away from the first imaginary plane S1, and a fourth concave curved surface 542 extending from the second magnet 520 side toward the center so as to move away from the first imaginary plane S1. The second yoke 540 also has a second yoke side parallel portion 543 formed in the center between the third concave curved surface 541 and the fourth concave curved surface 542 and formed parallel to the first imaginary plane S1.

[0053] 10 also shows the magnetic field emitted from the inner wall surface of the first yoke 530, passing through the inner region of the magnetic circuit 500, and proceeding toward the inner wall surface of the second yoke 540, indicated by multiple dashed arrows M4. As indicated by the dashed arrows M4, a portion of the magnetic field emitted from the first to fourth concave curved surfaces 531, 532, 541, and 542 of the yoke passes near the axis CL in the inner region of the magnetic circuit 500. Therefore, in the inner region of the magnetic circuit 500, including the axis CL and the region near the axis CL, the parallel magnetic field range in which only parallel components of the magnetic field exist without being affected by the magnetic field emitted from the first to fourth concave curved surfaces 531, 532, 541, and 542 is small. Therefore, in the configuration of the comparative example, if the magnetic detection unit 600 moves from its position on the axis CL to outside the parallel magnetic field range during use of the brake pedal device 2, the direction of the magnetic field passing through the magnetic detection unit 600 may change, even though the magnetic circuit 500 is not rotating. Therefore, in the rotation angle detection device 100 of the comparative example, when the magnetic detection unit 600 outputs a signal corresponding to the direction of the magnetic field that has changed due to its own movement, there is a risk that the detection accuracy of the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10 will decrease.

[0054] <Effects of the First Embodiment> Compared with the rotation angle detection device 100 of the comparative example, the rotation angle detection device 1 of the first embodiment has the following effects. (1) In the first embodiment, the first yoke 41 and the second yoke 42 are arranged facing each other in the second direction across the axis CL, and the distance D1 between the first magnets, the distance D2 between the second magnets, and the distance D3 between the yoke inner walls are the same. This configuration ensures that the magnetic field emitted from the portions of the yokes 41 and 42 near the magnets 31 and 32 and passing through the inner region of the magnetic circuit 30 does not affect the magnetic field emitted from the portions of the yokes 41 and 42 other than the central portion and passing through the inner region of the magnetic circuit 30. Note that the central portion of the yokes 41 and 42 refers to the portions of the yokes 41 and 42 other than the portions near the magnets 31 and 32. This allows the range of the parallel magnetic field to be increased in the axis CL and the inner region of the magnetic circuit 30, including the vicinity of the axis CL. Therefore, even if the magnetic detection unit 50 moves from the axis CL due to a misalignment between the housing 10 and the shaft member 20, the direction of the magnetic field passing through the magnetic detection unit 50 is prevented from changing due to the movement. Therefore, the rotation angle detection device 1 can improve the detection accuracy of the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10.

[0055] (2) In the first embodiment, both the first yoke inner wall surface 413 and the second yoke inner wall surface 423 are flat surfaces parallel to the first direction. This allows the magnetic field emitted from the first yoke inner wall surface 413, passing through the inner region of the magnetic circuit 30, and heading toward the second yoke inner wall surface 423 to be a parallel magnetic field. This allows the range of the parallel magnetic field to be increased in the inner region of the magnetic circuit 30, including the center axis CL and the vicinity of the center axis CL.

[0056] (3) In the first embodiment, both the first yoke inner wall surface 413 and the second yoke inner wall surface 423 are planar and parallel to the first direction, extending between the first magnet 31 and the second magnet 32. This allows the magnetic field in the region inside the magnetic circuit 30 to be a parallel magnetic field extending between the first magnet 31 and the second magnet 32. Therefore, the range of the parallel magnetic field can be increased in the region inside the magnetic circuit 30.

[0057] (4) In the first embodiment, both the first yoke 41 and the second yoke 42 can be flat or rectangular. This simplifies the configuration of the yokes 41 and 42, reducing the number of manufacturing steps. In this disclosure, the term "flat" refers to a substantially flat plate, and includes not only a completely flat plate but also slight deformations due to manufacturing tolerances, rounded corners, and the like. In this disclosure, the term "rectangular" refers to a substantially rectangular parallelepiped, and includes not only a completely rectangular parallelepiped but also slight deformations due to manufacturing tolerances, rounded corners, and the like.

[0058] (5) In the first embodiment, the magnetic circuit 30 is symmetrical with respect to the second imaginary plane S2. Accordingly, the direction and strength of the magnetic field in the region inside the magnetic circuit 30 are symmetrical with respect to the second imaginary plane S2. Therefore, even if the magnetic detection unit 50 moves from the axis CL to one side or the other in the first direction due to a misalignment between the housing 10 and the shaft member 20, changes in the direction and strength of the magnetic field passing through the magnetic detection unit 50 caused by the movement are suppressed. Therefore, the rotation angle detection device 1 can improve the detection accuracy of the rotation angle of the shaft member 20 and the brake pedal 21 despite a misalignment between the housing 10 and the shaft member 20 in the first direction.

[0059] (6) In the first embodiment, the magnetic circuit 30 is symmetrical with respect to both the second imaginary plane S2 and the first imaginary plane S1. As a result, the direction and strength of the magnetic field in the region inside the magnetic circuit 30 are symmetrical with respect to both the second imaginary plane S2 and the first imaginary plane S1. Therefore, even if the magnetic detection unit 50 is displaced in the first direction and the second direction from the axis CL due to a misalignment between the housing 10 and the shaft member 20, changes in the direction and strength of the magnetic field passing through the magnetic detection unit 50 caused by such movement are suppressed. Therefore, the rotation angle detection device 1 can improve the detection accuracy of the rotation angle of the shaft member 20 and the brake pedal 21 despite misalignment between the housing 10 and the shaft member 20 in the first direction and the second direction.

[0060] (7) In the first embodiment, the distance D4 between the first magnet 31 and the second magnet 32 ​​is greater than the distance D3 between the yoke inner walls. This increases the distance between the magnets 31 and 32 and the magnetic detection unit 50, thereby preventing the magnetic field leaking from the magnets 31 and 32 from affecting the magnetic field near the axis CL in the inner region of the magnetic circuit 30.

[0061] (8) In the first embodiment, the first magnet 31 and the second magnet 32 ​​can both be rectangular parallelepiped. This simplifies the configuration of the magnets 31 and 32, thereby reducing the number of manufacturing steps.

[0062] (9) In the first embodiment, both the first magnet 31 and the second magnet 32 ​​can be cylindrical. This simplifies the configuration of the magnets 31 and 32, reducing the number of manufacturing steps. Note that, in this disclosure, "cylindrical" refers to a substantially cylindrical shape in light of the intent of this disclosure, and includes not only a perfect cylinder but also slight deformations due to manufacturing tolerances, rounding of the ends, and the like.

[0063] (10) In the first embodiment, the magnetic detection unit 50 can be configured to perform one-axis detection. In this case, the IC or ECU 4 of the magnetic detection unit 50 calculates the direction of the magnetic field passing through the magnetic detection element 52 based on the magnitude of a signal output in accordance with the magnetic flux density passing through at least one magnetically sensitive surface 53 of the magnetic detection element 52. This simplifies the configuration of the magnetic detection element 52 and the angle detection logic of the rotation angle detection device 1, thereby reducing manufacturing costs.

[0064] (11) In the first embodiment, the magnetic detection unit 50 can be configured to perform two-axis detection. In this case, the magnetic detection element 52 has a first magnetically sensitive surface 54 arranged in a predetermined orientation and a second magnetically sensitive surface 55 arranged in a different orientation from the first magnetically sensitive surface 54. The IC or ECU 4 of the magnetic detection unit 50 calculates the direction of the magnetic field passing through the magnetic detection element 52 based on the magnitude of a signal output in response to the magnetic flux density passing through the first magnetically sensitive surface 54 and the magnitude of a signal output in response to the magnetic flux density passing through the second magnetically sensitive surface 55. According to this, the magnetic field strength in the region inside the magnetic circuit 30 increases with increasing distance from the first yoke 41 and the second yoke 42 (i.e., near the axis CL) to the intermediate position between the first yoke 41 and the second yoke 42. In contrast, two-axis detection can accurately detect the rotation angle even when the magnetic detection unit 50 moves from the axis CL to one side or the other side in the second direction.

[0065] (12) In the first embodiment, a Hall element can be used as the magnetic detection element 52. By using a versatile element as the magnetic detection element 52, manufacturing costs can be reduced.

[0066] (13) In the first embodiment, a magnetoresistive effect element can be used as the magnetic detection element 52. By using a versatile element as the magnetic detection element 52, manufacturing costs can be reduced.

[0067] (14) The rotation angle detection device 1 of the first embodiment is used in a brake pedal device 2 to detect the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10. Accordingly, the rotation angle detection device 1 used in the brake pedal device 2 is required to detect angles with high accuracy even when the housing 10 and the shaft member 20 are misaligned. To meet this requirement specific to the brake pedal device 2, the rotation angle detection device 1 can detect the rotation angles of the shaft member 20 and the brake pedal 21 with high accuracy even when the magnetic detection unit 50 moves from the axis CL due to misalignment between the housing 10 and the shaft member 20. Therefore, the brake pedal device 2 can prevent unintended sudden deceleration, for example, when the driver applies a small pedal force to the brake pedal 21. Furthermore, the brake pedal device 2 can prevent unintended braking, for example, when the driver is not applying a pedal force to the brake pedal 21 while the vehicle is traveling.

[0068] Second Embodiment A second embodiment will be described. In the second embodiment, a part of the configuration of the magnetic circuit 30 is changed from that of the first embodiment, and the other parts are the same as those of the first embodiment. Therefore, only the parts that are different from the first embodiment will be described.

[0069] 7, in the magnetic circuit 30 provided in the rotation angle detection device 1 of the second embodiment, the distance D1 between the first magnets and the distance D2 between the second magnets are both greater than the distance D3 between the yoke inner walls. Note that the distance D1 between the first magnets and the distance D2 between the second magnets are the same.

[0070] Specifically, a portion 411 of the first yoke 41 facing the N pole of the first magnet 31 and a portion 412 of the first yoke 41 facing the N pole of the second magnet 32 ​​are both provided on one side in the second direction of the first yoke inner wall surface 413. Therefore, a step 417 is provided between the portion 411 of the first yoke 41 facing the N pole of the first magnet 31 and the first yoke inner wall surface 413. A step 418 is also provided between the portion 412 of the first yoke 41 facing the N pole of the second magnet 32 ​​and the first yoke inner wall surface 413.

[0071] Similarly, a portion 421 of the second yoke 42 facing the south pole of the first magnet 31 and a portion 422 of the second yoke 42 facing the south pole of the second magnet 32 ​​are both provided on the other side in the second direction of the second yoke inner wall surface 423. Therefore, a step 427 is provided between the portion 421 of the second yoke 42 facing the south pole of the first magnet 31 and the second yoke inner wall surface 423. A step 428 is also provided between the portion 422 of the second yoke 42 facing the south pole of the second magnet 32 ​​and the second yoke inner wall surface 423.

[0072] In the second embodiment, both the first yoke inner wall surface 413 and the second yoke inner wall surface 423 are planar and parallel to the first direction, extending from the first magnet 31 to the second magnet 32. The magnetic circuit 30 is symmetrical with respect to the second imaginary plane S2 and is also symmetrical with respect to the first imaginary plane S1.

[0073] The second embodiment described above can also achieve the same effects as the first embodiment.

[0074] Third Embodiment A third embodiment will be described. The third embodiment is similar to the first and second embodiments except that the configuration of the magnetic circuit 30 is partially changed. Therefore, only the differences from the first embodiment will be described.

[0075] 8, in the magnetic circuit 30 included in the rotation angle detection device 1 of the third embodiment, the distance D1 between the first magnets and the distance D2 between the second magnets are both greater than the distance D3 between the yoke inner walls. Note that the distance D1 between the first magnets and the distance D2 between the second magnets are the same.

[0076] In the third embodiment, inclined portions 431 to 434 are provided in the yokes 41 and 42 at positions near the magnets 31 and 32. The inclined portions 431 to 434 face the magnet that is closest to them. Specifically, the first inclined portion 431 provided in the first yoke 41 at a position near the first magnet 31 faces the first magnet 31. The second inclined portion 432 provided in the first yoke 41 at a position near the second magnet 32 ​​faces the second magnet 32. Furthermore, the third inclined portion 433 provided in the second yoke 42 at a position near the first magnet 31 faces the first magnet 31. The fourth inclined portion 434 provided in the second yoke 42 at a position near the second magnet 32 ​​faces the second magnet 32.

[0077] The first yoke inner wall surface 413 has a first parallel portion 435 formed parallel to the first direction between the first inclined portion 431 and the second inclined portion 432. The second yoke inner wall surface 423 has a second parallel portion 436 formed parallel to the first direction between the first inclined portion 431 and the second inclined portion 432. The distance between both the first parallel portion 435 and the second parallel portion 436 is equal to or greater than half the distance D4 between the first magnet 31 and the second magnet 32.

[0078] The magnetic circuit 30 of the third embodiment described above is configured so that the magnetic field emitted from the inclined portions 431 to 434 and passing through the inner region of the magnetic circuit 30 does not affect the magnetic field emitted from the first parallel portion 435, passing through the inner region of the magnetic circuit 30, and heading toward the second parallel portion 436. This makes it possible to increase the range of the parallel magnetic field in the inner region of the magnetic circuit 30, including the axis CL and the vicinity of the axis CL. This allows the rotation angle detection device 1 to improve the detection accuracy of the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10.

[0079] (Fourth embodiment) A fourth embodiment will be described. The fourth embodiment is similar to the first to third embodiments except that the configuration of the magnetic circuit 30 is partially changed. Therefore, only the differences from the first embodiment will be described.

[0080] 9, the magnetic circuit 30 included in the rotation angle detection device 1 of the fourth embodiment has chamfered portions 441 to 444 at each of the four corners of the outer wall of the magnetic circuit 30 when viewed from the direction in which the axis CL extends. In this way, the shape of the outer wall of the magnetic circuit 30 can be changed as desired.

[0081] The fourth embodiment described above can also achieve the same effects as the first embodiment, etc. The shape of the outer wall of the magnetic circuit 30 is not limited to that exemplified in the fourth embodiment, and various shapes can be used, such as a circle, an ellipse, a polygon, or a combination thereof.

[0082] (Other Embodiments) (1) In each of the above embodiments, the rotation angle detection device 1 has been described as being used in a brake pedal device 2, but it is not limited to this and can be used in various products that have a support body and a rotating body, such as an accelerator pedal device or an electronic throttle.

[0083] (2) In the above embodiments, the brake pedal device 2 is described as being configured such that the shaft member 20 is rotatably provided with respect to the housing 10. However, the present invention is not limited to this, and the brake pedal 21 may be configured to be rotatable with respect to the shaft member 20 fixed to the housing 10. In this case, the rotation angle detection device 1 may be configured, for example, such that the magnetic circuit 30 is provided on the brake pedal 21 as a rotating body, and the magnetic detection unit 50 is provided on the housing 10 or the shaft member 20, and detects the rotation angle of the brake pedal 21 with respect to the housing 10.

[0084] (3) In each of the above embodiments, the inner wall surface of the magnetic circuit 30 is described as being formed in a rectangular shape when viewed from the direction in which the axis CL extends. However, this is not limited to this, and the rectangular shape may also be a shape in which the corners are slightly chamfered.

[0085] The present disclosure is not limited to the above-described embodiments and can be modified as appropriate. Furthermore, the above-described embodiments and portions thereof are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc. of components, etc. are mentioned, they are not limited to the shape, positional relationship, etc., unless specifically stated or limited to a specific shape, positional relationship, etc. in principle.

[0086] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. The memory is a non-transitory tangible storage medium.

[0087] (Viewpoints of the Present Disclosure) The above-described present disclosure can be understood from the following viewpoints, for example. [First Aspect] A rotation angle detection device for detecting a rotation angle of a rotating body (20, 21) rotatably provided relative to a support (10), comprising: a magnetic circuit (30) fixed to the rotating body, the magnetic circuit having a first magnet (31) and a second magnet (32) arranged opposite each other across a rotation axis (CL) of the rotating body and having the same magnetization direction, and a first yoke (41) and a second yoke (42) connecting the same poles of the first magnet and the second magnet; and a magnetic detection unit (50) fixed to the support so that the magnetic detection element (52) outputs an electric signal according to a magnetic field in an area inside the magnetic circuit, the magnetic detection unit (50) being fixed to the support so that the magnetic detection element is located on the axis, wherein a first direction is a direction in which an imaginary line connecting the center of the first magnet and the center of the second magnet extends, and a second direction is a direction in which the axis extends and a direction perpendicular to the first direction are defined; the first yoke and the second yoke are arranged opposite each other in the second direction across the axis, A rotation angle detection device in which "the distance (D1) between a portion (411) of the first yoke facing the north pole of the first magnet and a portion (421) of the second yoke facing the south pole of the first magnet" and "the distance (D2) between a portion (412) of the first yoke facing the north pole of the second magnet and a portion (422) of the second yoke facing the south pole of the second magnet" are both greater than or equal to "the distance (D3) between a surface (413) of the first yoke facing the second yoke between the first magnet and the second magnet and a surface (423) of the second yoke facing the first yoke between the first magnet and the second magnet." [Second Aspect] The rotation angle detection device according to the first aspect, in which the surface of the first yoke facing the second yoke between the first magnet and the second magnet and the surface of the second yoke facing the first yoke between the first magnet and the second magnet are both planar and parallel to the first direction.[Third Aspect] The rotation angle detection device according to the first or second aspect, wherein a surface of the first yoke facing the second yoke between the first magnet and the second magnet and a surface of the second yoke facing the first yoke between the first magnet and the second magnet are both planar and parallel to the first direction, extending between the first magnet and the second magnet. [Fourth Aspect] The rotation angle detection device according to any one of the first to third aspects, wherein the first yoke and the second yoke are both flat or rectangular. [Fifth Aspect] The rotation angle detection device according to any one of the first to fourth aspects, wherein the magnetic circuit is symmetrical with respect to a predetermined imaginary plane (S2) that includes the axis and is parallel to the second direction. [Sixth Aspect] The rotation angle detection device according to any one of the first to fifth aspects, wherein the magnetic circuit is symmetrical with respect to a predetermined imaginary plane that includes the axis and is parallel to the second direction, and is also symmetrical with respect to another imaginary plane (S1) that includes the axis and is parallel to the first direction. [Seventh Aspect] The rotation angle detection device according to any one of the first to sixth aspects, wherein the "distance (D4) between the first magnet and the second magnet" is greater than the "distance (D3) between a surface (413) of the first yoke facing the second yoke between the first magnet and the second magnet and a surface (423) of the second yoke facing the first yoke between the first magnet and the second magnet." [Eighth Aspect] The rotation angle detection device according to any one of the first to seventh aspects, wherein the first magnet and the second magnet are both rectangular parallelepiped. [Ninth Aspect] The rotation angle detection device according to any one of the first to seventh aspects, wherein the first magnet and the second magnet are both cylindrical. [Tenth Aspect] The rotation angle detection device according to any one of the first to ninth aspects, wherein the magnetic detection unit calculates the direction of a magnetic field passing through the magnetic detection element based on the magnitude of a signal output in accordance with the magnetic flux density passing through at least one magnetically sensitive surface (53) of the magnetic detection element.[Eleventh Aspect] The rotation angle detection device according to any one of the first to ninth aspects, wherein the magnetic detection unit calculates the direction of a magnetic field passing through the magnetic detection element based on the magnitude of a signal output in response to a magnetic flux density passing through a first magnetic sensing surface (54) of the magnetic detection element and the magnitude of a signal output in response to a magnetic flux density passing through a second magnetic sensing surface (55) that is arranged in an orientation different from that of the first magnetic sensing surface. [Twelfth Aspect] The rotation angle detection device according to any one of the first to eleventh aspects, wherein the magnetic detection element is a Hall element. [Thirteenth Aspect] The rotation angle detection device according to any one of the first to eleventh aspects, wherein the magnetic detection element is a magnetoresistive effect element. [Fourteenth Aspect] A rotation angle detection device according to any one of the first to thirteenth aspects, which is used in a brake pedal device (2) including the support (10) fixed to a vehicle body, a shaft member (20) provided on the support, and a brake pedal (21) rotatable with respect to the support within a predetermined angle range around the axis center (CL) of the shaft member, and which detects a rotation angle of the shaft member as the rotating body or the brake pedal as the rotating body relative to the support. [Fifteenth Aspect] A brake pedal device mounted on a vehicle, which includes: the support (10) fixed to the vehicle body, a shaft member (20) provided on the support, the brake pedal (21) rotatable with respect to the support within a predetermined angle range around the axis center (CL) of the shaft member, and the rotation angle detection device according to any one of the first to fourteenth aspects, which detects the rotation angle of the shaft member as the rotating body or the brake pedal as the rotating body relative to the support.

Claims

1. A rotation angle detection device for detecting the rotation angle of a rotating body (20, 21) rotatably provided with respect to a support (10), comprising: a magnetic circuit (30) fixed to the rotating body, the magnetic circuit having a first magnet (31) and a second magnet (32) arranged opposite each other across the axis of rotation (CL) of the rotating body and having the same magnetization direction, and a first yoke (41) and a second yoke (42) connecting the same poles of the first magnet and the second magnet, and a magnetic detection unit (50) fixed to the support so that the magnetic detection element is located on the axis, the magnetic detection unit having a magnetic detection element (52) that outputs an electric signal according to the magnetic field in an inner region of the magnetic circuit, the magnetic detection unit being fixed to the support; wherein the direction in which an imaginary line connecting the center of the first magnet and the center of the second magnet extends is defined as a first direction, and the direction in which the axis extends and a direction perpendicular to the first direction are defined as a second direction, the first yoke and the second yoke are arranged opposite each other in the second direction across the axis, A rotation angle detection device in which "the distance (D1) between a portion (411) of the first yoke facing the north pole of the first magnet and a portion (421) of the second yoke facing the south pole of the first magnet" and "the distance (D2) between a portion (412) of the first yoke facing the north pole of the second magnet and a portion (422) of the second yoke facing the south pole of the second magnet" are both greater than or equal to "the distance (D3) between a surface (413) of the first yoke facing the second yoke between the first magnet and the second magnet and a surface (423) of the second yoke facing the first yoke between the first magnet and the second magnet." 2. A rotation angle detection device as described in claim 1, wherein a surface of the first yoke between the first magnet and the second magnet facing the second yoke, and a surface of the second yoke between the first magnet and the second magnet facing the first yoke, are both planar and parallel to the first direction.

3. A rotation angle detection device as described in claim 1, wherein a surface of the first yoke between the first magnet and the second magnet facing the second yoke, and a surface of the second yoke between the first magnet and the second magnet facing the first yoke, are both planar and parallel to the first direction, extending between the first magnet and the second magnet.

4. A rotation angle detection device according to any one of claims 1 to 3, wherein the first yoke and the second yoke are both flat or rectangular.

5. A rotation angle detection device according to any one of claims 1 to 3, wherein the magnetic circuit is symmetrical with respect to a predetermined imaginary plane (S2) that includes the axis and is parallel to the second direction.

6. A rotation angle detection device as described in any one of claims 1 to 3, wherein the magnetic circuit is symmetrical with respect to a predetermined imaginary plane that includes the axis and is parallel to the second direction, and is also symmetrical with respect to another imaginary plane (S1) that includes the axis and is parallel to the first direction.

7. A rotation angle detection device as described in any one of claims 1 to 3, wherein "the distance (D4) between the first magnet and the second magnet" is greater than "the distance (D3) between a surface (413) of the first yoke facing the second yoke between the first magnet and the second magnet, and a surface (423) of the second yoke facing the first yoke between the first magnet and the second magnet." 8. A rotation angle detection device according to any one of claims 1 to 3, wherein the first magnet and the second magnet are both rectangular parallelepiped shaped.

9. A rotation angle detection device according to any one of claims 1 to 3, wherein the first magnet and the second magnet are both cylindrical.

10. A rotation angle detection device as described in any one of claims 1 to 3, wherein the magnetic detection unit calculates the direction of the magnetic field passing through the magnetic detection element based on the magnitude of a signal output in accordance with the magnetic flux density passing through at least one magnetic sensitive surface (53) of the magnetic detection element.

11. A rotation angle detection device as described in any one of claims 1 to 3, wherein the magnetic detection unit calculates the direction of the magnetic field passing through the magnetic detection element based on the magnitude of a signal output in response to the magnetic flux density passing through a first magnetic sensing surface (54) of the magnetic detection element and the magnitude of a signal output in response to the magnetic flux density passing through a second magnetic sensing surface (55) arranged in an orientation different from the orientation in which the first magnetic sensing surface is arranged.

12. A rotation angle detection device according to any one of claims 1 to 3, wherein the magnetic detection element is a Hall element.

13. A rotation angle detection device according to any one of claims 1 to 3, wherein the magnetic detection element is a magnetoresistance effect element.

14. A rotation angle detection device as described in any one of claims 1 to 3, which is used in a brake pedal device (2) comprising a support (10) fixed to a vehicle body, an axial member (20) provided on the support, and a brake pedal (21) provided relative to the support so as to be rotatable within a predetermined angle range around the axial center (CL) of the axial member, and which detects the rotation angle of the axial member as the rotating body or the brake pedal as the rotating body relative to the support.

15. A brake pedal device mounted on a vehicle, comprising: a support (10) fixed to a vehicle body; an axial member (20) provided on the support; a brake pedal (21) provided relative to the support so as to be rotatable within a predetermined angle range around the axial center (CL) of the axial member; and a rotation angle detection device according to any one of claims 1 to 3, which detects the rotation angle of the axial member as the rotating body or the brake pedal as the rotating body relative to the support.

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