Rotation angle detection device

Abstract

To provide a rotation angle detection device that is able to improve the detection accuracy of a rotation angle.SOLUTION: A rotation angle detection device 1 includes a magnetic circuit 30 and a magnetic detection unit 50. The magnetic circuit 30 includes a first magnet 31, a second magnet 32, a first yoke 41, and a second yoke 42, and is fixed to a rotating body. The magnetic detection unit 50 is fixed to a support body such that a magnetic detection element 52 is positioned on an axis CL of rotation of the rotating body. A direction in which an imaginary 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 in which the axis CL extends and a direction orthogonal to the first direction are defined as a second direction. The first yoke 41 and the second yoke 42 are disposed opposite each other in the second direction, with the axis CL interposed therebetween. Both a first inter-magnet distance D1 and a second inter-magnet distance D2 are greater than or equal to an inter-yoke-inner-wall distance D3.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a rotation angle detection device. [Background technology]

[0002] The rotation angle detection device described in Patent Document 1 is used, for example, in an electronic throttle of an automobile. The electronic throttle is configured such that 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.

[0003] The magnetic circuit of the rotation angle detection device has two magnets and two yokes. The two magnets are arranged facing 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 of the yokes has a first concave curved surface and a second concave curved surface in the vicinity of each of the two magnets, which extend from the magnet side toward the center and away from an imaginary line connecting the centers of the two magnets. Also, the one of the yokes has a parallel portion formed in the center between the first and second concave curved surfaces and parallel to the imaginary line. The other yoke also has a third concave curved surface and a fourth concave curved surface in the vicinity of each of the two magnets, which extend 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 concave curved surface and the fourth concave curved surface. 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 according to the direction of the magnetic field. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5818104 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the two yokes provided in the rotation angle detection device described in Patent Document 1 have first to fourth concave curved surfaces in the vicinity of 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 fields emitted from the first to fourth concave curved surfaces of the yoke pass near the axis in the inner region of the magnetic circuit. Therefore, in the inner region of the magnetic circuit including the axis and the vicinity of the axis, the parallel magnetic field range in which only parallel components of the magnetic field exist without being affected by the magnetic fields emitted from the first to fourth concave curved surfaces is small. Therefore, in this rotation angle detection device, if the housing and the shaft member are misaligned due to a clearance or the like caused by the rotational movement of the housing and the shaft member, and the magnetic detection unit moves from the position on the axis to the outside of the parallel magnetic field range, the detection accuracy of the rotation angle may decrease.

[0007] In view of the above, 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. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, a rotation angle detection device for detecting a rotation angle of a rotor (20, 21) rotatably provided with respect to a support (10) includes: a magnetic circuit (30) that is fixed to the rotor and includes a first magnet (31) and a second magnet (32) that are arranged opposite each other across the axis of rotation (CL) of the rotor and have the same magnetization direction, and a first yoke (41) and a second yoke (42) that connect the same poles of the first magnet and the second magnet, a magnetic detection unit (50) having a magnetic detection element (52) that outputs an electric signal corresponding to a magnetic field in an inner region of a magnetic circuit, the magnetic detection element being fixed to a support so that the magnetic detection element is located on an axis; If the direction in which a virtual 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 the direction perpendicular to the first direction are defined as a second direction, then: The first yoke and the second yoke are disposed opposite each other in the second direction across the axis, The "distance (D1) between the portion (411) of the first yoke facing the north pole of the first magnet and the portion (421) of the second yoke facing the south pole of the first magnet" and the "distance (D2) between the portion (412) of the first yoke facing the north pole of the second magnet and the 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 the surface (413) of the first yoke facing the second yoke between the first magnet and the second magnet and the surface (423) 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 makes it possible to increase the range of parallel magnetic fields in the inner region of the magnetic circuit including the axis and the vicinity of the axis. Therefore, even if the magnetic detection unit moves from the axis due to a positional deviation between the support and the rotating body, the direction of the magnetic field passing through the magnetic detection unit is prevented from changing due to the movement. Therefore, the rotation angle detection device can improve the detection accuracy of the rotation angle of the rotating body relative to the support.

[0011] According to another aspect of the present disclosure, a brake pedal device mounted on a vehicle includes: A support (10) fixed to a vehicle body; A shaft member (20) provided on the support; a brake pedal (21) rotatably provided on the support within a predetermined angle range around an axis (CL) of a shaft member; and a rotation angle detection device as described in one aspect of the present disclosure, which detects a rotation angle of a shaft member as a rotating body or a brake pedal as a rotating body relative to a support body.

[0012] According to this, for example, when the driver applies a small depression force to the brake pedal, if the brake pedal device erroneously detects an angle at which the brake pedal is depressed heavily, there is a risk of the driver suddenly decelerating unintentionally. Also, for example, when the driver does not apply a depression force to the brake pedal, if the brake pedal device erroneously detects an angle at which the brake pedal is depressed, there is a risk of the driver unintentionally applying the brakes while the vehicle is traveling. Therefore, the rotation angle detection device used in the brake pedal device is required to detect the rotation angle of the rotating body relative to the support body with high accuracy. On the other hand, in a brake pedal device, a shaft member or a brake pedal as a rotating body rotates relative to a support body, and therefore a clearance is provided between the support body and the rotating body, which may cause a positional deviation (i.e., axial deviation) between the support body and the rotating body. For these reasons, a rotation angle detection device used in a brake pedal device is required to detect an angle with high accuracy even if the support body and the rotating body are misaligned. In response to such requirements specific to a brake pedal device, a rotation angle detection device can detect the rotation angle of the rotating body relative to the support body with high accuracy even if the magnetic detection unit moves from the axis center due to a positional deviation between the support body and the rotating body.

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

[0014] [Figure 1] 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. [Diagram 2] 2 is a cross-sectional view perpendicular to the axis of a shaft member in the brake pedal device. FIG. [Diagram 3] 3 is a cross-sectional view taken along line III-III in FIG. 1 and FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 3, showing the configuration of the rotation angle detection device according to the first embodiment. [Diagram 5] FIG. 2 is an explanatory diagram for explaining one-axis detection in the rotation angle detection device. [Figure 6] FIG. 2 is an explanatory diagram for explaining two-axis detection in the rotation angle detection device. [Figure 7] FIG. 11 is a configuration diagram of a rotation angle detection device according to a second embodiment. [Figure 8] FIG. 11 is a configuration diagram of a rotation angle detection device according to a third embodiment. [Figure 9] FIG. 13 is a configuration diagram of a rotation angle detection device according to a fourth embodiment. [Figure 10] FIG. 1 is a configuration diagram of a rotation angle detection device of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals, and the 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 applies brakes to the vehicle. The brake-by-wire system 3 is a system in which a brake mechanism 5 applies brakes to the vehicle under drive control of an electronic control device (hereinafter referred to as "ECU 4") mounted on the vehicle. Note that ECU is an abbreviation for Electronic Control Unit.

[0017] <Brake pedal device and brake-by-wire system configuration> 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 serving as a support, a shaft member 20 serving as a rotating body, a brake pedal 21, and a rotation angle detection device 1.

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

[0020] The shaft member 20 is formed in a rod shape, and is supported by bearings 11 and 12 provided in the housing 10. The shaft member 20 is provided in the housing 10 so as to be rotatable within a predetermined angle range around its own axis CL as the center of rotation. 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 perform rotational movement.

[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 pedal pad 23 is provided at the other end. The pedal pad 23 is a 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 angle 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 composed of, 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 providing 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 storage unit such as a ROM and a RAM that stores programs and data, and the like, and peripheral circuits thereof. The storage unit is composed of a non-transient substantial storage medium. The ECU 4 performs various control processing and arithmetic processing based on the programs stored in the storage unit, and controls the operation of each device connected to the 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 electric signal transmitted from the rotation angle detection device 1, and controls the operation of the brake mechanism 5.

[0025] Various mechanisms can be used 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 a disc brake rotor to brake 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, drive wheel cylinders arranged on each wheel, and operate the brake pads.

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

[0027] As shown in FIG. 3 and FIG. 4, the rotation angle detection device 1 includes 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 formed in a rectangular tube shape. Therefore, when viewed from the direction in which the axis CL extends, the inner wall surface of the magnetic circuit 30 is formed in a rectangular shape. As shown in FIG. 3, the first magnet 31, the second magnet 32, the first yoke 41, and the second yoke 42 are fixed to the end of the shaft member 20 by a bolt (not shown) or the like in a state in which they are molded by a resin body 33. Therefore, the positional relationship between the magnetic circuit 30 and the axis CL of the shaft member 20 is fixed. Note that in FIG. 4 to FIG. 6 and FIG. 7 to FIG. 10 referred to in each embodiment and comparative example below, the illustration of the resin body 33 that molds the magnetic circuit 30 and the hatching showing the cross section of each member 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 according to the magnetic field in the region inside the magnetic circuit 30. In detail, the magnetic detection element 52 outputs an electric signal according to the magnitude of the magnetic flux density passing through its own magnetic sensing surface in the magnetic field in the region inside the magnetic circuit 30. For example, a Hall element or a magnetoresistance element can be used as the magnetic detection element 52. The Hall element or the magnetoresistance element is incorporated in an integrated circuit (hereinafter referred to as "IC"). IC is an abbreviation 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, snap-fitting, etc. Note that "so that the magnetic detection element 52 is located on the axis CL" refers to disposing the magnetic detection element 52 on the axis CL of the shaft member 20 in terms of design (i.e., on paper). 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, etc.

[0030] 4 shows a state in which the magnetic detection element 52 of the magnetic detection unit 50 is located 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 the shaft member 20 to rotate. Therefore, during use of the brake pedal device 2, 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 range of the inner region of the magnetic circuit 30.

[0031] In the following description, the direction in which an imaginary line connecting the center of the first magnet 31 and the center of the second magnet 32 ​​extends is referred to as the "first direction" as shown in Fig. 4. The direction in which the axis CL extends and the direction perpendicular to the first direction are referred to as the "second direction". The first magnet 31 side with respect to the axis CL will be referred to as the "one side of the first direction", the second magnet 32 ​​side with respect to the axis CL as the "other side of the first direction", the first yoke 41 side with respect to the axis CL as the "one side of the second direction", and the second yoke 42 side with respect to the axis CL as the "other side of the second direction". Furthermore, in the following description, a certain imaginary surface that includes the axis CL and is parallel to the second direction will be referred to as a "second imaginary surface S2," and another imaginary surface that includes the axis CL and is parallel to the first direction will be referred to as a "first imaginary surface S1."

[0032] The first magnet 31 and the second magnet 32 ​​are arranged to face each other in the first direction across the axis CL of the shaft member 20. Note that "facing" means that they are arranged to face each other. Both the first magnet 31 and the second magnet 32 ​​are permanent magnets, and are formed in a rectangular parallelepiped or cylindrical shape. Both the first magnet 31 and the second magnet 32 ​​are arranged so that their magnetization directions are parallel to the second direction and are the same. Specifically, the first magnet 31 and the second magnet 32 ​​are arranged so that their N poles face one side of the second direction and their S poles face the other side of the second direction.

[0033] The first yoke 41 and the second yoke 42 are disposed facing 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 a magnetic material and are formed in a flat plate shape or a rectangular parallelepiped shape. Both 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 N pole of the first magnet 31 and the N pole of the second magnet 32. The second yoke 42 connects the S pole of the first magnet 31 and the S pole of the second magnet 32.

[0034] The first yoke 41 and the second yoke 42 are arranged parallel to the first direction. In detail, 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 a plane parallel to the first direction 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 a plane parallel to the first direction from the first magnet 31 to the second magnet 32.

[0035] In this disclosure, "parallel" means substantially parallel in light of the gist 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" means substantially flat in light of the gist 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 N pole of the first magnet 31 and a portion 421 of the second yoke 42 facing the S pole of the first magnet 31 is referred to as a first inter-magnet distance D1. The distance between a portion 412 of the first yoke 41 facing the N pole of the second magnet 32 ​​and a portion 422 of the second yoke 42 facing the S pole of the second magnet 32 ​​is referred to as a 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 a yoke inner wall distance D3.

[0037] In the first embodiment, the first inter-magnet distance D1, the second inter-magnet distance D2, and the yoke inner wall distance D3 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 completely the same, but also slight non-identity due to, for example, manufacturing tolerances.

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

[0039] 4, for the sake 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. Also, 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 as a continuous plane.

[0040] 4, for the sake of explanation, the boundary between a portion 421 of the second yoke 42 facing the S pole of the first magnet 31 and the 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 S 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 S pole of the first magnet 31, the second yoke inner wall surface 423, and the portion 422 of the second yoke 42 facing the S pole of the second magnet 32 ​​are formed as 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" means substantially symmetrical in the context of the present disclosure, and includes not only perfect symmetry but also slight asymmetrical states 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 and the distance between the second magnet 32 ​​and the second imaginary plane S2 are the same. The first yoke 41 has the same shape, size, material properties, etc., between a portion on one side and a portion on the other side across the second imaginary plane S2. The second yoke 42 also has the same shape, size, material properties, etc., between a portion on one side and a portion on the other side across 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. The first magnet 31 has the same shape, size, material properties, etc., between a portion on one side and a portion on the other side across the first imaginary plane S1. The second magnet 32 ​​also has the same shape, size, material properties, etc., between a portion on one side and a portion on the other side across the first imaginary plane S1.

[0044] Here, in general, the magnetic field emitted from the inner wall surface of the yoke into the 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 becomes a substantially parallel magnetic field. Therefore, even if the magnetic detection unit 50 moves from the axis center CL during use of the brake pedal device 2, the direction of the magnetic field passing through the magnetic detection unit 50 due to the movement is suppressed from changing. 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 where the magnetic circuit 30 has rotated a predetermined angle clockwise from the state shown in FIG. 4 relative to the magnetic detection unit 50. 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 magnetic sensing surface 53. The magnetic detection unit 50 outputs a signal according to the magnetic flux density passing through the magnetic sensing surface 53 arranged in a predetermined direction. When the direction of the magnetic field passing through the magnetic sensing surface 53 of the magnetic detection element 52 changes with the rotation of the magnetic circuit 30, the magnetic flux density passing through the magnetic sensing surface 53 changes accordingly. In FIG. 5, for the sake of explanation, the direction and magnitude of the magnetic field passing through the magnetic detection element 52 are indicated by an arrow M2, and the magnitude of the signal output by the magnetic detection element 52 according to the magnetic flux density passing through the magnetic sensing surface 53 is indicated by an 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 according to 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 where the magnetic circuit 30 has rotated a predetermined angle clockwise from the state of FIG. 4 with respect to the magnetic detection unit 50. In FIG. 6, the angle by which the magnetic circuit 30 has rotated from the state of 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 a plurality of magnetic sensing surfaces 54, 55. Among the plurality of magnetic sensing surfaces 54, 55, the first magnetic sensing surface 54 and the second magnetic sensing surface 55 are arranged in different directions (specifically, perpendicular directions). Therefore, the magnetic flux density passing through the first magnetic sensing surface 54 and the magnetic flux density passing through the second magnetic sensing surface 55 are different from each other with respect to the direction of the magnetic field passing through the magnetic detection element 52 as the magnetic circuit 30 rotates. Therefore, the magnetic detection element 52 outputs a signal having a different magnitude based on the magnetic flux density passing through the first magnetic sensing surface 54 and a signal having a different magnitude based on the magnetic flux density passing through the second magnetic sensing surface 55.

[0048] 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, the magnitude of the signal output based on the magnetic flux density passing through the first magnetic sensitive 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 sensitive 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, i.e., the rotation angle θ2 of the magnetic circuit 30, by the arc tangent from the magnitude of the signal output based on the magnetic flux density passing through the first magnetic sensitive surface 54 and the magnitude of the signal output based on the magnetic flux density passing through the second magnetic sensitive surface 55. 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 strength of the magnetic field 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, in the above-mentioned one-axis detection, when 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, in the two-axis detection, the rotation angle can be detected with high accuracy even if the magnetic detection unit 50 moves from the axis CL to one side or the other side in the second direction due to the clearances C1, C2 between the shaft member 20 and the bearings 11, 12, etc.

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

[0051] As shown in Fig. 10, the rotation angle detector 100 of the comparative example also includes a magnetic circuit 500 and a magnetic detector 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 so as to move away from the first imaginary surface S1, and a second concave curved surface 532 extending from the second magnet 520 side toward the center so as to move away from the first imaginary surface S1. The first yoke 530 also includes a first yoke-side parallel portion 533 formed in the center between the first concave curved surface 531 and the second concave curved surface 532 and parallel to the first imaginary surface S1.

[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 surface 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 surface 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 surface S1.

[0053] 10, 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 heading toward the inner wall surface of the second yoke 540 is indicated by a plurality of dashed arrows M4. As indicated by the dashed arrows M4, some of the magnetic fields emitted from the first to fourth concave curved surfaces 531, 532, 541, and 542 of the yoke pass 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 vicinity of the axis CL, the parallel magnetic field range in which only parallel components of the magnetic field exist without being influenced by the magnetic fields emitted from the first to fourth concave curved surfaces 531, 532, 541, and 542 is small. Therefore, in the rotation angle detection device 100 of the comparative example, when the magnetic detection unit 600 moves from a position on the axis CL to the outside of 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 change in the direction of the magnetic field 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 above-mentioned comparative example, the rotation angle detection device 1 of the first embodiment has the following advantages. (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 first inter-magnet distance D1, the second inter-magnet distance D2, and the yoke inner wall distance D3 are the same. According to this, the magnetic field emitted from the portion of the yoke 41, 42 near the magnets 31, 32 and passing through the inner region of the magnetic circuit 30 does not affect the magnetic field emitted from the portion of the yoke 41, 42 other than the central portion and passing through the inner region of the magnetic circuit 30. The central portion of the yoke 41, 42 refers to the portion of the yoke 41, 42 other than the portion near the magnets 31, 32. This makes it possible to increase the parallel magnetic field range in the inner region of the magnetic circuit 30 including the axis CL and the vicinity of the axis CL. Therefore, even if the magnetic detection unit 50 moves from the axis CL due to the positional deviation between the housing 10 and the shaft member 20, the direction of the magnetic field passing through the magnetic detection unit 50 due to the movement is suppressed from changing. 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, first yoke inner wall surface 413 and second yoke inner wall surface 423 are both flat surfaces parallel to the first direction. This allows the magnetic field emitted from first yoke inner wall surface 413 to pass through the inner region of magnetic circuit 30 toward second yoke inner wall surface 423 to be a parallel magnetic field. Therefore, the range of the parallel magnetic field can be increased in the inner region of magnetic circuit 30 including axis CL and the vicinity of axis CL.

[0056] (3) In the first embodiment, first yoke inner wall surface 413 and second yoke inner wall surface 423 each extend between first magnet 31 and second magnet 32 ​​and are planar in shape parallel to the first direction. According to this, the magnetic field in the region inside the magnetic circuit 30 can be made parallel across the area between the first magnet 31 and the second magnet 32. Therefore, the range of the parallel magnetic field in the region inside the magnetic circuit 30 can be made large.

[0057] (4) In the first embodiment, the first yoke 41 and the second yoke 42 can both be formed in a flat plate shape or a rectangular parallelepiped shape. This simplifies the configuration of the yokes 41 and 42, thereby reducing the number of manufacturing steps. In this disclosure, the term "flat plate-like" refers to a substantially flat plate in light of the gist of this disclosure, and includes, in addition to a completely flat plate, slight deformations due to manufacturing tolerances, rounding of corners, etc. In addition, in this disclosure, the term "rectangular parallelepiped-like" refers to a substantially rectangular parallelepiped in light of the gist of this disclosure, and includes, in addition to a completely rectangular parallelepiped, slight deformations due to manufacturing tolerances, rounding of corners, etc.

[0058] (5) In the first embodiment, the magnetic circuit 30 is symmetrical with respect to the second imaginary plane S2. According to this, the direction and strength of the magnetic field in the inner region of 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 side in the first direction due to a positional deviation between the housing 10 and the shaft member 20, the direction and strength of the magnetic field passing through the magnetic detection unit 50 are 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 in response to a positional deviation 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 the second imaginary plane S2 and is symmetrical with respect to the first imaginary plane S1. According to this, the direction and strength of the magnetic field in the inner region of the magnetic circuit 30 are symmetrical with respect to the second imaginary plane S2 and also with respect to 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 the displacement of the housing 10 and the shaft member 20, the direction and strength of the magnetic field passing through the magnetic detection unit 50 due to the movement are suppressed from changing. 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 in response to the displacement of 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. According to this, by increasing the distance between the magnets 31, 32 and the magnetic detection unit 50, it is possible to prevent the magnetic field leaking from the magnets 31, 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, and reduces the number of manufacturing steps.

[0062] (9) In the first embodiment, the first magnet 31 and the second magnet 32 ​​can both be cylindrical. This simplifies the configuration of the magnets 31 and 32, and reduces the number of manufacturing steps. In this disclosure, "cylindrical" refers to a substantial cylinder 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, etc.

[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 according to the magnetic flux density passing through at least one magnetic sensing surface 53 of the magnetic detection element 52. This allows the rotation angle detection device 1 to have a simple configuration for the magnetic detection element 52 and a simple logic for angle detection, 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 magnetic sensing surface 54 arranged in a predetermined direction and a second magnetic sensing surface 55 arranged in a different direction from the first magnetic sensing 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 the signal output according to the magnetic flux density passing through the first magnetic sensing surface 54 and the magnitude of the signal output according to the magnetic flux density passing through the second magnetic sensing surface 55. According to this, the strength of the magnetic field 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). In contrast, with two-axis detection, the rotation angle can be detected with high accuracy 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, the manufacturing cost can be reduced.

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

[0067] (14) The rotation angle detection device 1 of the first embodiment is used in a brake pedal device 2 and detects the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10. According to this, the rotation angle detection device 1 used in the brake pedal device 2 is required to detect angles with high accuracy even when there is a positional deviation between the housing 10 and the shaft member 20. In response to the requirement specific to the brake pedal device 2, the rotation angle detection device 1 can detect the rotation angle of the shaft member 20 and the brake pedal 21 relative to the housing 10 with high accuracy even when the magnetic detection unit 50 moves from the axis CL due to a positional deviation between the housing 10 and the shaft member 20. Therefore, the brake pedal device can prevent the driver from suddenly decelerating unintentionally when the driver applies a small depression force to the brake pedal, for example. Also, the brake pedal device can prevent the driver from applying the brakes unintentionally when the driver is not applying a depression force to the brake pedal while the vehicle is traveling, for example.

[0068] Second embodiment The 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 other parts are the same as those of the first embodiment, so only the parts that are different from the first embodiment will be described.

[0069] 7, in the magnetic circuit 30 included in the rotation angle detection device 1 of the second embodiment, the first inter-magnet distance D1 and the second inter-magnet distance D2 are both greater than the yoke inner wall distance D3. The first inter-magnet distance D1 and the second inter-magnet distance D2 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 relative to 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 S pole of the first magnet 31 and a portion 422 of the second yoke 42 facing the S pole of the second magnet 32 ​​are both provided on the other side in the second direction than the second yoke inner wall surface 423. Therefore, a step 427 is provided between the portion 421 of the second yoke 42 facing the S 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 S pole of the second magnet 32 ​​and the second yoke inner wall surface 423.

[0072] In the second embodiment, both first yoke inner wall surface 413 and second yoke inner wall surface 423 are planar and parallel to the first direction, extending from first magnet 31 to second magnet 32. Magnetic circuit 30 is symmetrical with respect to second imaginary plane S2, and is also symmetrical with respect to 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 a part of the configuration of the magnetic circuit 30 is changed, and therefore only the parts different 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 first inter-magnet distance D1 and the second inter-magnet distance D2 are both greater than the yoke inner wall distance D3. Note that the first inter-magnet distance D1 and the second inter-magnet distance D2 are the same.

[0076] In the third embodiment, the inclined portions 431 to 434 are provided in the yokes 41 and 42 at the portions 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 the portion near the first magnet 31 faces the first magnet 31 side. The second inclined portion 432 provided in the first yoke 41 at the portion near the second magnet 32 ​​faces the second magnet 32 ​​side. The third inclined portion 433 provided in the second yoke 42 at the portion near the first magnet 31 faces the first magnet 31 side. The fourth inclined portion 434 provided in the second yoke 42 at the portion near the second magnet 32 ​​faces the second magnet 32 ​​side.

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

[0078] The magnetic circuit 30 of the third embodiment described above is configured such that the magnetic field emitted from the inclined portions 431-434 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 proceeding 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 a part of the configuration of the magnetic circuit 30 is changed, and therefore only the parts different 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 441-444 provided at four corners of the outer wall of the magnetic circuit 30 when viewed from the direction in which the axis CL extends. In this manner, 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 and so on. The shape of the outer wall of the magnetic circuit 30 is not limited to that exemplified in the fourth embodiment, but may be various shapes, 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 the use 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 each of the above embodiments, the brake pedal device 2 has been described as having a configuration in which 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 rotatably provided 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 in the brake pedal 21 as a rotating body, and the magnetic detection unit 50 is provided in 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-mentioned embodiments, and can be appropriately modified within the scope of the claims. In addition, the above-mentioned embodiments and parts thereof are not unrelated to each other, and can be appropriately combined except when the combination is clearly impossible. In addition, in each of the above-mentioned embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered to be essential in principle. In addition, in each of the above-mentioned embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiment are mentioned, they are not limited to the specific numbers, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. In addition, in each of the above-mentioned embodiments, when the shape, positional relationship, etc. of the components are mentioned, they are not limited to the shape, positional relationship, etc., except when it is specifically stated that they are essential or when it is clearly limited to a specific shape, positional relationship, etc. in principle.

[0086] (In view of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] A rotation angle detection device for detecting a rotation angle of a rotor (20, 21) rotatably mounted on a support (10), comprising: a magnetic circuit (30) fixed to the rotating body, the magnetic circuit (30) including a first magnet (31) and a second magnet (32) arranged opposite to 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; a magnetic detection unit (50) having a magnetic detection element (52) that outputs an electric signal corresponding to a magnetic field in an area inside the magnetic circuit, the magnetic detection element being fixed to the support body so that the magnetic detection element is located on the axis; If the direction in which a virtual 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 the direction perpendicular to the first direction are defined as a second direction, The first yoke and the second yoke are disposed 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 N pole of the first magnet and a portion (421) of the second yoke facing the S pole of the first magnet" and "the distance (D2) between a portion (412) of the first yoke facing the N pole of the second magnet and a portion (422) of the second yoke facing the S 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 viewpoint] A rotation angle detection device described in a first aspect, 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. [Third Perspective] A rotation angle detection device described in the first or second aspect, 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. [Fourth viewpoint] 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 viewpoint] 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 viewpoint] A rotation angle detection device as described in 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 viewpoint] A 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 viewpoint] 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 shaped. [Ninth viewpoint] 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. [10th viewpoint] The rotation angle detection device according to any one of the first to ninth aspects, wherein the magnetic detection unit calculates a direction of a magnetic field passing through the magnetic detection element based on a magnitude of a signal output according to a magnetic flux density passing through at least one magnetic sensitive surface (53) of the magnetic detection element. [Eleventh viewpoint] A 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 sensitive 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 sensitive surface (55) arranged in an orientation different from that in which the first magnetic sensitive surface is arranged. [12th viewpoint] The rotation angle detection device according to any one of the first to eleventh aspects, wherein the magnetic detection element is a Hall element. [13th viewpoint] The rotation angle detection device according to any one of the first to eleventh aspects, wherein the magnetic detection element is a magnetoresistance effect element. [14th viewpoint] A rotation angle detection device as described in any one of the first to thirteenth aspects, which is used in a brake pedal device (2) including a support body (10) fixed to a vehicle body, an axis member (20) provided on the support body, and a brake pedal (21) provided relative to the support body so as to be rotatable within a predetermined angle range around the axis center (CL) of the axis member, and detects a rotation angle of the axis member as the rotating body or the brake pedal as the rotating body relative to the support body. [15th viewpoint] A brake pedal device mounted on a vehicle, The support (10) is fixed to a vehicle body; A shaft member (20) provided on the support; a brake pedal (21) provided on the support so as to be rotatable within a predetermined angular range around the axis (CL) of the shaft member; A brake pedal device comprising: a rotation angle detection device according to any one of the first to fourteenth aspects, 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 body. [Explanation of symbols]

[0087] 1: rotation angle detection device, 10: housing (support), 20: shaft member (rotating body), 21: brake pedal (rotating body), 30: magnetic circuit, 31: first magnet, 32: second magnet, 41: first yoke, 42: second yoke, 50: magnetic detection unit, 52: magnetic detection element, 411: portion of first yoke facing the N pole of the first magnet, 412: portion of first yoke facing the N pole of the second magnet, 413: surface of first yoke facing the second yoke between the first magnet and the second magnet, 421: portion of second yoke facing the S pole of the first magnet, 422: portion of second yoke facing the S pole of the second magnet, 423: surface of second yoke facing the first yoke between the first magnet and the second magnet, CL: axis, D1: distance between first magnets, D2: distance between second magnets, D3: distance between yoke inner walls

Claims

1. A rotation angle detection device for detecting a rotation angle of a rotor (20, 21) rotatably provided with respect to a support (10), 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; a magnetic detection unit (50) having a magnetic detection element (52) that outputs an electric signal corresponding to a magnetic field in an area inside the magnetic circuit, the magnetic detection element being fixed to the support body so that the magnetic detection element is located on the axis; If a direction in which a virtual line connecting the center of the first magnet and the center of the second magnet extends is defined as a first direction, and a 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 disposed opposite to 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. 2. The rotation angle detection device of 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. 2. The rotation angle detection device of 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. 4. The rotation angle detection device according to claim 1, wherein the first yoke and the second yoke are both in the shape of a flat plate or a rectangular parallelepiped.

5. 4. The rotation angle detection device according to claim 1, 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. 4. The rotation angle detection device according to claim 1, 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 according to 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. 4. The rotation angle detection device according to claim 1, wherein the first magnet and the second magnet are both rectangular parallelepiped shaped.

9. 4. The rotation angle detection device according to claim 1, wherein the first magnet and the second magnet are both cylindrical.

10. 4. The rotation angle detection device according to claim 1, wherein the magnetic detection unit calculates a direction of a magnetic field passing through the magnetic detection element based on a magnitude of a signal output in accordance with a magnetic flux density passing through at least one magnetic sensitive surface (53) of the magnetic detection element.

11. 4. 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 sensitive 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 sensitive surface (55) arranged in an orientation different from that in which the first magnetic sensitive surface is arranged.

12. 4. The rotation angle detection device according to claim 1, wherein the magnetic detection element is a Hall element.

13. 4. The rotation angle detection device according to claim 1, wherein the magnetic detection element is a magnetoresistance effect element.

14. 4. A rotation angle detection device according to claim 1, which is used in a brake pedal device (2) including 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 a 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, The support (10) is fixed to a vehicle body; A shaft member (20) provided on the support; a brake pedal (21) provided to be rotatable within a predetermined angle range around the axis (CL) of the shaft member relative to the support; 4. A brake pedal device comprising: a rotation angle detection device according to claim 1, 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 body.

Images