JP7480758B2 - Rotation Angle Detection Device - Google Patents

Description

This disclosure relates to a rotation angle detection device.

As described in Patent Document 1, a rotation angle detection device that detects the rotation angle of a detection target such as a steering shaft of a vehicle is known. This rotation angle detection device includes a rotating body, a detection body, a magnetic detection unit, a control unit, an upper case, and a lower case. The rotating body is formed in an annular shape and has a circular central through hole into which a part of the steering shaft is inserted. The detection body rotates together with the attached magnet in conjunction with the rotation of the rotating body. The magnetic detection unit detects changes in magnetic flux from the magnet. The control unit calculates the rotation angle based on a signal from the magnetic detection unit. The upper case has a circular opening corresponding to the central through hole of the rotating body. The lower case has a circular opening corresponding to the central through hole of the rotating body. The upper case is connected to the lower case so as to cover the lower case in which the rotating body and the detection body are arranged.

JP 2015-178992 A

According to the inventors' study, the rotation angle detection device described in Patent Document 1 is assembled by inserting the rotor of the rotation angle detection device into the opening of the upper case or the opening of the lower case. At this time, the upper case, the lower case, and the rotor are assembled by moving them in the axial direction of the rotor, so it is difficult to adjust the positions of the upper case, the lower case, and the rotor in a direction perpendicular to the axial direction of the rotor. This increases the variation in the distance between the axis of the rotor and the axis of the detection body in a direction perpendicular to the axial direction of the rotor. This increases the variation in the position of the detection body that rotates with the rotor, and therefore increases the variation in the positional relationship between the detection body and the magnetic detection unit. This increases the variation in the magnetic field that passes through the magnetic detection unit among the magnetic fields generated by the magnet attached to the detection body. This increases the variation in the signal from the magnetic detection unit, and therefore reduces the detection accuracy of the rotation angle.

The present disclosure aims to provide a rotation angle detection device that improves the detection accuracy of the rotation angle of a detection target.

The invention described in claim 1 is a rotation angle detection device that detects the rotation angle of a detection object, and includes a driving rotor (35) that rotates with the detection object, a driven rotor (31) that rotates with the driving rotor, an angle magnet (51) that generates a magnetic field and rotates with the driven rotor, an angle detection unit (81) that detects the strength of the magnetic field that corresponds to the rotation angle and changes as the driven rotor rotates, a case base (411) that rotatably supports the driven rotor by contacting the driven rotor and the axial direction (Da) of the driven rotor, and a case (40) having case side surfaces (431, 471) that are connected to the inner peripheral edge of the case base and are formed in the side shape of an arc column that corresponds to the rotation trajectory of the driving rotor, and the driving rotor is a rotation angle detection device that faces the case side surface in a direction perpendicular to the axial direction (Da) of the driving rotor.

This allows the driving rotor to be attached to the case by moving it in a direction perpendicular to the axial direction of the driving rotor. This makes it easier to adjust the position of the driving rotor in the direction perpendicular to the axial direction. This reduces the variation in the distance between the axis of the driving rotor and the axis of the driven rotor in the direction perpendicular to the axial direction. This reduces the variation in the position of the driven rotor that rotates with the driving rotor, thereby reducing the variation in the positional relationship between the driven rotor and the angle detection unit. This improves the detection accuracy of the magnetic field strength by the angle detection unit, and therefore the detection accuracy of the rotation angle of the detection target.

The invention described in claim 11 is a rotation angle detection device for detecting the rotation angle of a detection object, comprising a rotating body (35) that rotates together with the detection object, a first receiving coil (701) that generates a voltage by electromagnetic induction, a second receiving coil (702) that generates a voltage by electromagnetic induction, an excitation coil (703) surrounding the first receiving coil and the second receiving coil, a magnetic field generating unit (704) that generates a magnetic field inside the first receiving coil and the second receiving coil by applying an AC voltage to the excitation coil, and a magnetic field generating unit (705) that generates a magnetic field inside the first receiving coil and the second receiving coil by rotating together with the rotating body. The rotation angle detection device includes a conductor (706) that changes the voltage generated in the first and second receiving coils by changing the magnetic field passing through it, a detection unit (705) that detects the voltage that changes as the conductor rotates, which corresponds to the rotation angle, and a case (40) that has a case base (411) facing the axial direction (Da) of the rotor, and case side surfaces (431, 471) that are connected to the inner peripheral edge of the case base and are formed into the side shape of an arc column that corresponds to the rotation trajectory of the rotor, and the rotor faces the case side surface in a direction perpendicular to the axial direction (Da) of the rotor.

This allows the rotor to be attached to the case by moving it in a direction perpendicular to the axial direction of the rotor. This makes it easier to adjust the position of the rotor in the direction perpendicular to the axial direction, which makes it easier to adjust the position of the conductor that rotates with the rotor. This reduces variation in the positional relationship between the conductor and the first and second receiving coils. This reduces variation in the voltage generated in the first and second receiving coils, improving the accuracy of voltage detection by the detection unit, and therefore improving the accuracy of detection of the rotation angle of the detection object.

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.

1 is a configuration diagram of a steering system in which a torque angle sensor corresponding to a rotation angle detection device of a first embodiment is used; FIG. 2 is an exploded perspective view of a portion of the steering system. FIG. FIG. FIG. 5 is a view taken along the arrow V in FIG. 4 . FIG. 6 is a view taken along line VI in FIG. 5 . FIG. 7 is a view taken along the line VII in FIG. 5 . FIG. 8 is an enlarged cross-sectional view taken along line VIII-VIII in FIG. 5 . FIG. 9 is an enlarged cross-sectional view taken along line IX-IX of FIG. 5 . FIG. 6 is an enlarged cross-sectional view taken along line XX of FIG. 5 . An enlarged cross-sectional view taken along line XI-XI of FIG. 5 . FIG. 4 is a side view showing a torque detection magnet, a first yoke, and a second yoke of the torque angle sensor in a neutral state. FIG. 4 is a side view of a torque detection magnet, a first yoke, and a second yoke of the torque angle sensor when a steering wheel of the steering system is rotated. FIG. 4 is a side view of the torque detection magnet, the first yoke, and the second yoke of the torque angle sensor when the steering wheel is rotated. FIG. 4 is a relationship diagram of the output of a first angle magnetic detection unit and a second angle magnetic detection unit of the torque angle sensor, and the steering angle. FIG. 4 is a relationship diagram of the torque angle sensor between the rotation angle of a first driven gear, the rotation angle of a second driven gear, and the steering angle. FIG. 6 is a cross-sectional view of a torque angle sensor according to a second embodiment. FIG. 11 is a cross-sectional view of a torque angle sensor according to a third embodiment. FIG. 13 is an exploded perspective view showing a part of a torque angle sensor according to a fourth embodiment. Cross-sectional view taken along line XX-XX in Figure 19. FIG. FIG. 13 is a cross-sectional view of a torque angle sensor according to a fifth embodiment. FIG. 13 is a cross-sectional view of a torque angle sensor according to a sixth embodiment. FIG. 13 is a perspective view showing a portion of a torque angle sensor according to a seventh embodiment. FIG. 4 is an exploded perspective view showing a part of the torque angle sensor. FIG. FIG. 2 is a configuration diagram of a first receiving coil, a second receiving coil, an excitation coil, a high-frequency transmitting circuit, and an output circuit of a torque angle sensor. FIG. 4 is a diagram showing a first region and a second region of a first receiving coil. FIG. 13 is a diagram showing the third region, the fourth region, and the fifth region of the second receiving coil. 5 is a relationship diagram of the steering angle, the voltage applied to the excitation coil, the voltage generated in the first receiving coil, and the voltage generated in the second receiving coil. 6 is a diagram showing the positional relationship between the first receiving coil and the conductor when the conductor rotates. FIG. 13 is a diagram showing the positional relationship between the second receiving coil and the conductor when the conductor rotates. FIG. 6 is a diagram showing the positional relationship between the first receiving coil and the conductor when the conductor rotates. FIG. 13 is a diagram showing the positional relationship between the second receiving coil and the conductor when the conductor rotates. FIG. 6 is a diagram showing the positional relationship between the first receiving coil and the conductor when the conductor rotates. FIG. 13 is a diagram showing the positional relationship between the second receiving coil and the conductor when the conductor rotates. FIG. 6 is a diagram showing the positional relationship between the first receiving coil and the conductor when the conductor rotates. FIG. 13 is a diagram showing the positional relationship between the second receiving coil and the conductor when the conductor rotates. FIG. FIG. 13 is a cross-sectional view of a torque angle sensor according to an eighth embodiment. FIG. 13 is an exploded perspective view showing a torque angle sensor according to a ninth embodiment. FIG. 23 is an exploded perspective view showing a torque angle sensor according to a tenth embodiment. FIG. FIG. 23 is a perspective view showing a portion of a torque angle sensor according to an eleventh embodiment. FIG. An arrow view from XXXXV in Figure 44. FIG. FIG. 4 is a diagram showing the relationship between the output of the torque angle sensor and the steering angle when no steering torque is generated. FIG. 4 is a relationship diagram between the output of a torque angle sensor and the steering angle when a steering torque is generated. FIG. 23 is a cross-sectional view of a torque angle sensor according to a twelfth embodiment. FIG. 4 is a cross-sectional view of a torque angle sensor according to another embodiment. FIG. 4 is a cross-sectional view of a torque angle sensor according to another embodiment. FIG. 4 is a cross-sectional view of a torque angle sensor according to another embodiment. FIG. 4 is a cross-sectional view of a torque angle sensor according to another embodiment. FIG. 11 is a diagram showing the configuration of a first receiving coil, a second receiving coil, and an exciting coil of a torque angle sensor according to another embodiment. FIG. 13 is an exploded perspective view showing a torque angle sensor according to another embodiment. FIG. 13 is an exploded perspective view showing a torque angle sensor according to another embodiment.

The following embodiments will be described with reference to the drawings. Note that in the following embodiments, parts that are identical or equivalent to each other will be given the same reference numerals and their description will be omitted.

First Embodiment
The rotation angle detection device of this embodiment is used, for example, in a steering system 1 mounted on a vehicle. First, the steering system 1 will be described.

The steering system 1 assists steering to change the direction of the wheels 17. Specifically, as shown in Figures 1 and 2, the steering system 1 includes a steering wheel 5, a first steering shaft 11, a torsion bar 13, and a second steering shaft 12. The steering system 1 also includes a shaft pin 14, a pinion gear 15, a rack shaft 16, wheels 17, a torque angle sensor 25, a motor control device 18, a motor 19, and a reduction gear 20.

As shown in FIG. 1, the steering wheel 5 rotates when steered by the vehicle driver or by an automatic driving system.

The first steering shaft 11 is connected to the steering wheel 5. Therefore, the first steering shaft 11 rotates together with the steering wheel 5.

The torsion bar 13 is connected to the first steering shaft 11. Therefore, the torsion bar 13 rotates together with the steering wheel 5 and the first steering shaft 11.

The second steering shaft 12 is connected to the torsion bar 13. Therefore, the torsion bar 13 rotates together with the steering wheel 5, the first steering shaft 11, and the torsion bar 13.

As shown in FIG. 2, the shaft pin 14 is inserted into a hole formed in the first steering shaft 11 and a hole in the torsion bar 13 that corresponds to the hole in the first steering shaft 11. This fixes the first steering shaft 11 and the torsion bar 13. The shaft pin 14 is also inserted into a hole formed in the second steering shaft 12 and a hole in the torsion bar 13 that corresponds to the hole in the second steering shaft 12. This fixes the second steering shaft 12 and the torsion bar 13.

As shown in FIG. 1, the pinion gear 15 is connected to the second steering shaft 12. The pinion gear 15 also meshes with the rack shaft 16, which will be described later. Furthermore, the pinion gear 15 converts the rotational motion of the second steering shaft 12 into the linear motion of the rack shaft 16.

The rack shaft 16 is connected to the wheels 17 via a tie rod or the like (not shown). The rack shaft 16 also changes the orientation of the wheels 17 by moving linearly.

A part of the torsion bar 13 is inserted into the torque angle sensor 25. The torque angle sensor 25 detects a signal corresponding to the torsional torque generated in the torsion bar 13 by the rotation of the steering wheel 5. As a result, the torque angle sensor 25 detects the steering torque. The torque angle sensor 25 outputs a signal corresponding to the detected steering torque to the motor control device 18 described below. The torque angle sensor 25 corresponds to a rotation angle detection device, and outputs a signal corresponding to the steering angle to the motor control device 18 described below. Details of the torque angle sensor 25 will be described later. The steering torque is the torque applied when the steering wheel 5 rotates. The steering angle is the rotation angle of the steering wheel 5.

The motor control device 18 is mainly composed of a microcomputer and includes a CPU, ROM, flash memory, RAM, I/O, drive circuits, and bus lines connecting these components. The motor control device 18 also executes a program stored in the ROM to calculate the rotation angle of the motor 19 (described below), and calculates the steering torque based on a signal corresponding to the steering torque from the torque angle sensor 25. The motor control device 18 also controls the rotation of the motor 19 (described below) based on the calculated rotation angle of the motor 19, the steering torque, and the steering angle calculated by the torque angle sensor 25.

The motor 19 rotates based on the output from the motor control device 18. This causes the motor 19 to generate torque.

The reduction gear 20 is connected to the motor 19 and the second steering shaft 12. The reduction gear 20 also reduces the rotation speed of the motor 19 and transmits the torque generated by the motor 19 to the second steering shaft 12. This assists in steering to change the direction of the wheels 17.

The steering system 1 is configured as described above. Next, the configuration of the torque angle sensor 25 will be explained.

As shown in Figures 2 to 11, the torque angle sensor 25 includes a torque detection magnet 30, a driving gear 35, a first driven gear 31, a second driven gear 32, a case 40, a first angle detection magnet 51, and a second angle detection magnet 52. The torque angle sensor 25 also includes a substrate 60, a first torque magnetic detector 61, a second torque magnetic detector 62, a support member 70, a first magnetic induction member 71, and a second magnetic induction member 72. The torque angle sensor 25 also includes a first angle magnetic detector 81, a second angle magnetic detector 82, a rotation angle calculator 83, a terminal connection hole 84, a terminal 85, a cover member 86, and a protective cover 90.

As shown in FIG. 2, the torque detection magnet 30 is formed in a circular ring shape. The torque detection magnet 30 is connected to the end of the first steering shaft 11. A part of the torsion bar 13 is inserted into the hole of the torque detection magnet 30. The axis of the torque detection magnet 30 is positioned on the same axis as the axis of the torsion bar 13. Therefore, the torque detection magnet 30 rotates around the axis of the torsion bar 13 together with the first steering shaft 11. The torque detection magnet 30 is magnetized so that the magnetic poles are alternately reversed in the rotation direction of the torque detection magnet 30.

As shown in Figures 3 to 11, the main driving gear 35 is formed in a cylindrical shape. In addition, the axis of the main driving gear 35 is positioned coaxially with the axis of the torque detection magnet 30. Therefore, the axis of the main driving gear 35, the axis of the torque detection magnet 30, and the axis of the torsion bar 13 are coaxial. Furthermore, the main driving gear 35 has a main driving gear portion 350, a cover recess 364, a main driving large diameter portion 351, a main driving protrusion 352, a main driving small diameter portion 353, a first yoke 361, a second yoke 362, and a fixing collar 354.

Hereinafter, for convenience, the radial direction of the main driving gear 35 will be simply referred to as the radial direction. Also, the axial direction Da of the main driving gear 35 will be simply referred to as the axial direction Da. Furthermore, the circumferential direction around the axis of the main driving gear 35 will be simply referred to as the circumferential direction.

The driving gear portion 350 is formed of resin or the like. The driving gear portion 350 also includes a driving annular portion 363 and a plurality of driving teeth portions 365. The driving annular portion 363 is formed in an annular shape. The driving teeth portions 365 protrude radially outward from the driving annular portion 363.

The cover recess 364 is a recess for attaching the protective cover 90 (described later) to the driving gear 35. As shown in Figures 8 to 11, the cover recess 364 also includes a cover recess side surface 366 and a cover recess bottom surface 367.

The cover recess side surface 366 is connected to the end surface of the driving annular portion 363 facing the axial direction Da. In addition, the cover recess side surface 366 is formed in the shape of a cylindrical side surface.

The cover recess bottom surface 367 is connected to the cover recess side surface 366. In addition, the cover recess bottom surface 367 is formed in a circular ring shape.

The driving large diameter portion 351 is formed in an annular shape. The driving large diameter portion 351 is connected to the driving annular portion 363 and the driving teeth portion 365 in the axial direction Da.

The driving convex portion 352 protrudes in the axial direction Da from the radially outer side of the driving large diameter portion 351 and opposite the driving gear portion 350.

The driving small diameter portion 353 is formed in an annular shape. In addition, the driving small diameter portion 353 is connected to the driving large diameter portion 351 on the opposite side to the driving gear portion 350 in the axial direction Da. Furthermore, the outer diameter of the driving small diameter portion 353 is smaller than the outer diameter of the driving large diameter portion 351. In addition, the driving small diameter portion 353 includes a plurality of first holes 391 and a plurality of second holes 392.

As shown in Figs. 8 and 9, the first hole 391 is a hole into which a part of the first yoke 361 described later is inserted. The first hole 391 is formed at a predetermined interval in the circumferential direction. The second hole 392 is a hole into which a part of the second yoke 362 described later is inserted, as shown in Figs. 10 and 11. The second hole 392 is formed at a predetermined interval in the circumferential direction. In addition, for example, the driving gear part 350, the cover recess 364, the driving large diameter part 351, the driving convex part 352, the driving small diameter part 353, the first yoke 361 described later, and the second yoke 362 described later are integrally molded. As a result, a part of the first yoke 361 described later is inserted into the driving small diameter part 353, and a part of the second yoke 362 described later is inserted into the driving small diameter part 353. In addition, the driving gear portion 350, the cover recess 364, the driving large diameter portion 351, the driving protrusion 352, the driving small diameter portion 353, and the first yoke 361 and second yoke 362 described below may be separate bodies.

As shown in Figures 2 and 8 to 11, the first yoke 361 is formed in an annular shape from a soft magnetic material. The first yoke 361 also includes a first yoke annular portion 370, a plurality of first yoke protrusions 371, and a plurality of first yoke claw portions 372.

The first yoke annular portion 370 is formed in an annular shape. The first yoke annular portion 370 is connected to the driving annular portion 363 in the axial direction Da. The first yoke annular portion 370 is also connected to the driving protrusion portion 352 in the radial direction.

As shown in Figs. 8 and 9, the first yoke protrusions 371 protrude radially inward from the first yoke annular portion 370. A portion of the first yoke protrusions 371 is inserted into the first holes 391. Furthermore, since the first holes 391 are formed at a predetermined interval in the circumferential direction, the first yoke protrusions 371 are formed at a predetermined interval in the circumferential direction.

The first yoke claw portion 372 protrudes in the axial direction Da from the side of the first yoke protrusion portion 371 opposite to the first yoke annular portion 370. The first yoke claw portion 372 is formed in a tapered shape in which the width of the first yoke claw portion 372 decreases from the first yoke protrusion portion 371 side toward the tip side. The first yoke claw portion 372 is connected to the inner surface of the driven small diameter portion 353. The first yoke claw portion 372 faces the outer surface of the torque detection magnet 30 in the radial direction. Since the first yoke protrusion portion 371 is formed at a predetermined interval in the circumferential direction, the first yoke claw portion 372 is formed at a predetermined interval in the circumferential direction.

As shown in Figures 2 and 8 to 11, the second yoke 362 is formed of a soft magnetic material in an annular shape, similar to the first yoke 361. The second yoke 362 also includes a second yoke annular portion 380, a plurality of second yoke protrusions 381, and a plurality of second yoke claw portions 382.

The second yoke annular portion 380 is formed in an annular shape. The second yoke annular portion 380 is connected to the outer surface of the driving small diameter portion 353.

As shown in Figs. 10 and 11, the second yoke protrusions 381 protrude radially inward from the second yoke annular portion 380. A portion of the second yoke protrusions 381 is inserted into the second holes 392. Furthermore, since the second holes 392 are formed at a predetermined interval in the circumferential direction, the second yoke protrusions 381 are formed at a predetermined interval in the circumferential direction.

The second yoke claw portion 382 protrudes in the axial direction Da from the side of the second yoke protrusion portion 381 opposite to the second yoke annular portion 380. The second yoke claw portion 382 is formed in a tapered shape in which the width of the second yoke claw portion 382 decreases from the second yoke protrusion portion 381 side toward the tip side. The second yoke claw portion 382 is connected to the inner surface of the driving small diameter portion 353. The second yoke claw portion 382 faces the outer surface of the torque detection magnet 30 in the radial direction. Since the second yoke protrusion portion 381 is formed at a predetermined interval in the circumferential direction, the second yoke claw portion 382 is formed at a predetermined interval in the circumferential direction. The second yoke claw portion 382 is disposed between the first yoke claw portions 372 adjacent to each other. Therefore, the first yoke claw portion 372 and the second yoke claw portion 382 are disposed alternately in the circumferential direction.

As shown in Figures 8 to 11, the fixing collar 354 is formed in a cylindrical shape. The fixing collar 354 is connected to the inner surface of the main driving small diameter portion 353. The fixing collar 354 is further connected to the second steering shaft 12. Therefore, the main driving gear 35 rotates together with the second steering shaft 12.

The first driven gear 31 is made of resin or the like. Furthermore, the axis of the first driven gear 31 is parallel to the axis of the driving gear 35, as shown in Figures 3 and 8. Furthermore, the first driven gear 31 includes a first driven gear portion 310, a first driven large diameter portion 311, a first driven small diameter portion 312, and a first magnet recess 315.

The first driven gear portion 310 includes a first driven cylindrical portion 313 and a plurality of first driven teeth portions 314. The first driven cylindrical portion 313 is formed in a cylindrical shape. The first driven teeth portions 314 protrude radially outward from the first driven cylindrical portion 313. A portion of one first driven tooth portion 314 is located between adjacent driving teeth portions 365. Therefore, the first driven gear 31 meshes with the driving gear 35. Furthermore, here, the number of first driven teeth portions 314 corresponding to the number of teeth of the first driven gear 31 is different from the number of driving teeth portions 365 corresponding to the number of teeth of the driving gear 35.

The first driven large diameter portion 311 is formed in a cylindrical shape. The first driven large diameter portion 311 is also connected to the first driven cylindrical portion 313 in the axial direction Da.

The first driven small diameter portion 312 is formed in a cylindrical shape. The first driven small diameter portion 312 is connected to the side of the first driven large diameter portion 311 opposite the first driven cylindrical portion 313 in the axial direction Da. The outer diameter of the first driven small diameter portion 312 is smaller than the outer diameter of the first driven large diameter portion 311.

The first magnet recess 315 is a recess for attaching the first angle detection magnet 51 described below to the first driven gear 31. The first magnet recess 315 is formed on the side of the first driven small diameter portion 312 opposite the first driven large diameter portion 311. The first magnet recess 315 further includes a first magnet recess side surface 316 and a first magnet recess bottom surface 317.

The first magnet recess side surface 316 is connected to the end surface of the first driven small diameter portion 312 opposite the first driven large diameter portion 311. The first magnet recess bottom surface 317 is connected to the first magnet recess side surface 316.

The second driven gear 32, like the first driven gear 31, is made of resin or the like. Furthermore, the axis of the second driven gear 32 is parallel to the axis of the driving gear 35 and the axis of the first driven gear 31, as shown in Figures 3 and 9. Furthermore, the second driven gear 32 includes a second driven gear portion 320, a second driven large diameter portion 321, a second driven small diameter portion 322, and a second magnet recess 325.

The second driven gear portion 320 includes a second driven cylindrical portion 323 and a plurality of second driven teeth portions 324. The second driven cylindrical portion 323 is formed in a cylindrical shape. The second driven teeth portions 324 protrude radially outward from the second driven cylindrical portion 323. A portion of one second driven tooth portion 324 is located between adjacent driving teeth portions 365. Therefore, the second driven gear 32 meshes with the driving gear 35. Furthermore, here, the number of second driven teeth portions 324 corresponding to the number of teeth of the second driven gear 32 is different from the number of driving teeth portions 365 corresponding to the number of teeth of the driving gear 35 and the number of first driven teeth portions 314 corresponding to the number of teeth of the first driven gear 31.

The second driven large diameter portion 321 is formed in a cylindrical shape. The second driven large diameter portion 321 is also connected to the second driven cylindrical portion 323 in the axial direction Da.

The second driven small diameter portion 322 is formed in a cylindrical shape. The second driven small diameter portion 322 is connected to the side of the second driven large diameter portion 321 opposite to the second driven cylindrical portion 323 in the axial direction Da. The outer diameter of the second driven small diameter portion 322 is smaller than the outer diameter of the second driven large diameter portion 321.

The second magnet recess 325 is a recess for attaching the second angle detection magnet 52 described below to the second driven gear 32. The second magnet recess 325 is formed on the opposite side of the second driven small diameter portion 322 to the second driven large diameter portion 321. The second magnet recess 325 further includes a second magnet recess side surface 326 and a second magnet recess bottom surface 327.

The second magnet recess side surface 326 is connected to the end surface of the second driven small diameter portion 322 opposite the second driven large diameter portion 321. The second magnet recess bottom surface 327 is connected to the second magnet recess side surface 326.

The case 40 is made of resin or the like. As shown in Figures 3 to 11, the case 40 has a case base 41, a terminal storage section 42, a driving recess 43, a first driven recess 401, a second driven recess 402, a cover pin 44, a case protrusion 45, and a board pin 46.

The case base 41 is formed in a plate shape extending in a direction perpendicular to the axial direction Da. The case base 41 is also formed in an arc shape centered on an axis extending in the axial direction Da. The case base 41 is further provided with a driving gear 35 attached in a direction perpendicular to the axial direction Da. The case base 41 is further provided with a first driven gear 31 and a second driven gear 32 attached in the axial direction Da. The case base 41 further includes a case base surface 411.

The case base surface 411 is a surface perpendicular to the axial direction Da. As shown in FIG. 8, the case base surface 411 supports the first driven gear 31 by contacting the first driven large diameter portion 311. When the first driven gear 31 rotates, the first driven large diameter portion 311 slides on the case base surface 411. As shown in FIG. 9, the case base surface 411 supports the second driven gear 32 by contacting the second driven large diameter portion 321. When the second driven gear 32 rotates, the second driven large diameter portion 321 slides on the case base surface 411.

As shown in Figures 3, 4, 6, 7, 10, and 11, the terminal storage section 42 protrudes from the case base surface 411 in the axial direction Da. The terminal storage section 42 is formed in a cylindrical shape. As shown in Figure 5, the terminal storage section 42 stores the terminal 85, which will be described later.

The drive recess 43 is a recess for mounting the drive gear 35 to the case base 41. As shown in Figures 3 and 8 to 11, the drive recess 43 includes a drive recess side surface 431 and a drive recess bottom surface 432.

The drive recess side surface 431 is connected to the inner peripheral edge of the case base surface 411. The drive recess side surface 431 is formed in the shape of a side surface of an arc column. Therefore, the drive recess side surface 431 has a shape that corresponds to the outer surface of the annular drive large diameter portion 351 and drive protrusion portion 352.

The drive recess bottom surface 432 is connected to the drive recess side surface 431. The drive recess bottom surface 432 is formed in an arc shape. Therefore, the drive recess side surface 431 has a shape corresponding to the end surface of the drive convex portion 352 facing the axial direction Da. Furthermore, the drive recess bottom surface 432 supports the drive gear 35 by contacting the drive convex portion 352.

The first driven recess 401 is a recess for attaching the first driven gear 31 to the case base 41. As shown in FIG. 8, the first driven recess 401 includes a first driven recess side surface 403 and a first driven recess bottom surface 404.

The first driven recess side surface 403 is connected to the case base surface 411. The first driven recess side surface 403 is also formed in the shape of a cylindrical side surface.

The first driven recess bottom surface 404 is connected to the first driven recess side surface 403. The first driven recess bottom surface 404 is formed in a circular shape. The first driven small diameter portion 312 is inserted into the first space 408 defined by the first driven recess bottom surface 404 and the first driven recess side surface 403.

The second driven recess 402 is a recess for attaching the second driven gear 32 to the case base 41. As shown in FIG. 9, the second driven recess 402 includes a second driven recess side surface 405 and a second driven recess bottom surface 406.

The second driven recess side surface 405 is connected to the case base surface 411. In addition, the second driven recess side surface 405 is formed in the shape of a cylindrical side surface.

The second driven recess bottom surface 406 is connected to the second driven recess side surface 405. The second driven recess bottom surface 406 is formed in a circular shape. The second driven small diameter portion 322 is inserted into the second space 409 defined by the second driven recess bottom surface 406 and the second driven recess side surface 405.

The cover pin 44 is a pin for attaching the protective cover 90 (described later) to the case 40. As shown in Figures 3 to 9, the cover pin 44 protrudes from the case base surface 411 in the axial direction Da.

As shown in Figures 3, 4, and 6 to 11, the case protrusion 45 protrudes from a portion of the case base 41 opposite the case base surface 411. This forms a board space 453 partitioned by the case protrusion 45 and the case base 41 as shown in Figures 8 to 11. This board space 453 and the first space 408 are separated by the case base 41. Furthermore, this board space 453 and the second space 409 are separated by the case base 41. Furthermore, the case protrusion 45 includes a case convex end surface 451 and a case convex side surface 452.

The case convex end surface 451 is the end surface of the case convex portion 45 opposite the case base portion 41. A board opening 454 is formed above the case convex end surface 451 and is a space that opens toward the axial direction Da.

The case convex side surface 452 is connected to the case base surface 411 and the case convex end surface 451. In addition, as shown in FIG. 3, a portion of the case convex side surface 452 is formed into the side shape of an arc column and is connected to the bottom surface 432 of the active recess.

The board pin 46 is a pin for attaching the board 60 (described later) to the case 40. As shown in Figures 8 to 11, the board pin 46 protrudes from the case base 41 in the axial direction Da and is located within the board space 453 defined by the case protrusion 45 and the case base 41.

As shown in FIG. 8, the first magnet 51 for angle detection is inserted into a space defined by the side surface 316 of the recess for the first magnet and the bottom surface 317 of the recess for the first magnet. Therefore, when the first driven gear 31 rotates, the first magnet 51 for angle detection rotates together with the first driven gear 31. In addition, in the initial state in which the steering wheel 5 is not rotating, one side of the first magnet 51 for angle detection in the first direction D1 is magnetized, for example, to the N pole. Furthermore, in the initial state in which the steering wheel 5 is not rotating, the other side of the first magnet 51 for angle detection in the first direction D1 is magnetized, for example, to the S pole. As a result, magnetic lines pass from the N pole of the first magnet 51 for angle detection through the case base 41, the first magnetic detection unit 81 for angle described later, the case base 41, and the S pole of the first magnet 51 for angle detection. The first direction D1 is the direction of a straight line that connects the axis of the driving gear 35 and the axis of the first driven gear 31 and is perpendicular to the axial direction Da.

As shown in FIG. 9, the second magnet 52 for angle detection is inserted into a space defined by the second magnet recess side surface 326 and the second magnet recess bottom surface 327. Therefore, when the second driven gear 32 rotates, the second magnet 52 for angle detection rotates together with the second driven gear 32. In addition, in the initial state in which the steering wheel 5 is not rotating, one side of the second magnet 52 for angle detection in the second direction D2 is magnetized, for example, to the N pole. Furthermore, in the initial state in which the steering wheel 5 is not rotating, the other side of the second magnet 52 for angle detection in the second direction D2 is magnetized, for example, to the S pole. As a result, magnetic lines pass from the N pole of the second magnet 52 for angle detection through the case base 41, the second magnetic detection unit 82 for angle described later, the case base 41, and the S pole of the second magnet 52 for angle detection. The second direction D2 is the direction of a straight line connecting the axis of the driving gear 35 and the axis of the second driven gear 32, which is perpendicular to the axial direction Da.

The board 60 is a printed circuit board. The board 60 is inserted into the board space 453 defined by the case protrusion 45 and the case base 41 by moving it in the axial direction Da through the board opening 454 defined by the case protrusion end face 451. The board 60 also has a board hole 601 formed therein.

A part of the board pin 46 is inserted into the board hole 601. This fixes the board 60 to the case 40.

The first torque magnetic detection unit 61 is mounted on a substrate 60 as shown in Figs. 3 and 10. The first torque magnetic detection unit 61 has, for example, a Hall element and an MR element, not shown. Here, the first torque magnetic detection unit 61 detects the strength of the magnetic field in the axial direction Da applied to the first torque magnetic detection unit 61. The first torque magnetic detection unit 61 outputs a signal corresponding to the strength of the detected magnetic field to the motor control device 18. MR is an abbreviation for Magneto Resistive.

The second torque magnetic detection unit 62 is mounted on the substrate 60 as shown in Figs. 3 and 11. The second torque magnetic detection unit 62 also has, for example, a Hall element and an MR element, not shown. Here, the second torque magnetic detection unit 62 detects the strength of the magnetic field in the axial direction Da applied to the second torque magnetic detection unit 62, similar to the first torque magnetic detection unit 61. Furthermore, the second torque magnetic detection unit 62 outputs a signal corresponding to the strength of the detected magnetic field to the motor control device 18.

The support member 70 is attached to the substrate 60 as shown in Figures 3, 10, and 11. The support member 70 is made of resin or the like. Furthermore, the support member 70 faces a part of the first yoke annular portion 370 in the axial direction Da.

The first magnetic induction member 71 is made of a soft magnetic material. A part of the first magnetic induction member 71 is supported by the support member 70. The part of the first magnetic induction member 71 supported by the support member 70 faces the axial direction Da at a position close to the first yoke annular portion 370 by the support member 70. The first magnetic induction member 71 extends from the part of the first magnetic induction member 71 supported by the support member 70 toward the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62. This extending part is bent, so that it faces the axial direction Da at a position close to the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62.

The second magnetic induction member 72 is made of a soft magnetic material. As shown in Figs. 10 and 11, a part of the second magnetic induction member 72 is attached to the surface of the substrate 60 opposite to the surface on which the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 are mounted. A part of the second magnetic induction member 72 faces the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 in the axial direction Da. The second magnetic induction member 72 extends from a part of the second magnetic induction member 72 toward the second yoke annular portion 380. This extending portion is bent so that it faces the axial direction Da at a position close to the second yoke annular portion 380.

The first magnetic detection unit for angle 81 is mounted on the substrate 60 as shown in FIG. 3 and FIG. 8. The first magnetic detection unit for angle 81 faces the portion of the case base 41 facing the first magnet for angle detection 51 in the axial direction Da. As a result, the magnetic field lines from the N pole of the first magnet for angle detection 51 pass through the first magnetic detection unit for angle 81 via the case base 41. Furthermore, the first magnetic detection unit for angle 81 has a first element and a second element not shown. The first element and the second element are, for example, a Hall element and an MR element. Furthermore, the first element of the first magnetic detection unit for angle 81 detects the strength of the magnetic field in the first direction D1 among the magnetic fields passing through the first magnetic detection unit for angle 81. Furthermore, the second element of the first magnetic detection unit for angle 81 detects the strength of the magnetic field in the direction perpendicular to the first direction D1 among the magnetic fields passing through the first magnetic detection unit for angle 81. The first magnetic angle detector 81 also outputs a signal corresponding to the strength of the detected magnetic field to the rotation angle calculator 83, which will be described later. As described above, the first direction D1 is the direction of a straight line that connects the axis of the driving gear 35 and the axis of the first driven gear 31 and is perpendicular to the axial direction Da.

The second magnetic detection unit for angle 82 is mounted on the substrate 60 as shown in FIG. 3 and FIG. 9. The second magnetic detection unit for angle 82 faces the portion of the case base 41 facing the second magnet for angle detection 52 in the axial direction Da. As a result, the magnetic field lines from the N pole of the second magnet for angle detection 52 pass through the second magnetic detection unit for angle 82 via the case base 41. Furthermore, the second magnetic detection unit for angle 82 has a first element and a second element not shown. The first element and the second element are, for example, a Hall element and an MR element. Furthermore, the first element of the second magnetic detection unit for angle 82 detects the strength of the magnetic field in the second direction D2 among the magnetic fields passing through the second magnetic detection unit for angle 82. Furthermore, the second element of the second magnetic detection unit for angle 82 detects the strength of the magnetic field in the direction perpendicular to the second direction D2 among the magnetic fields passing through the second magnetic detection unit for angle 82. The second angle magnetic detector 82 outputs a signal corresponding to the strength of the detected magnetic field to the rotation angle calculator 83, which will be described later. As described above, the second direction D2 is the direction of a straight line that connects the axis of the driving gear 35 and the axis of the second driven gear 32 and is perpendicular to the axial direction Da.

The rotation angle calculation unit 83 is mounted on the substrate 60 as shown in FIG. 3. The rotation angle calculation unit 83 is disposed between the first angle magnetic detection unit 81 and the second angle magnetic detection unit 82. The rotation angle calculation unit 83 is mainly composed of a microcomputer and includes a CPU, ROM, flash memory, RAM, I/O, and bus lines connecting these components. The rotation angle calculation unit 83 executes a program stored in the ROM to calculate a value related to the steering angle based on the signal from the first angle magnetic detection unit 81 and the second angle magnetic detection unit 82.

The terminal connection hole 84 is formed in the substrate 60. The terminal connection hole 84 is disposed in the circumferential direction between the first torque magnetic detector 61, the second torque magnetic detector 62, the first angle magnetic detector 81, the second angle magnetic detector 82, and the rotation angle calculation unit 83.

As shown in FIG. 5, the terminal 85 is accommodated in the terminal accommodation section 42 of the case 40. A part of the terminal 85 is inserted into the terminal connection hole 84. A part of the terminal 85 is soldered, so that the terminal 85 is connected to the board 60. The terminal 85 is also connected to the motor control device 18. Therefore, signals from the first torque magnetic detection section 61, the second torque magnetic detection section 62, and the rotation angle calculation section 83 are output to the motor control device 18 via the terminal 85. Furthermore, as described above, the terminal connection hole 84 is arranged in the circumferential direction between the first torque magnetic detection section 61, the second torque magnetic detection section 62, and the first angle magnetic detection section 81, the second angle magnetic detection section 82, and the rotation angle calculation section 83. For this reason, the terminal 85 is disposed in the circumferential direction between the first torque magnetic detector 61, the second torque magnetic detector 62, the first angle magnetic detector 81, the second angle magnetic detector 82, and the rotation angle calculation unit 83.

As shown in Figures 3, 4, and 6 to 11, the lid member 86 is formed of resin or the like in a plate shape. The lid member 86 is connected to the case convex end surface 451. The connection surface of the lid member 86 and the case convex end surface 451 are welded together, for example, by a laser or the like. This closes the board opening 454. The connection surface of the lid member 86 and the case convex end surface 451 may be bonded together by an adhesive or the like.

The protective cover 90 is made of resin or the like. As shown in Figures 3 to 11, the protective cover 90 covers a part of the driving gear 35, a part of the first driven gear 31, and a part of the second driven gear 32. Specifically, the protective cover 90 has a driving cover portion 900, a first driven cover portion 901, a second driven cover portion 902, a cover protrusion 903, and a cover hole 904.

The drive cover portion 900 is formed in a shape that corresponds to the drive gear portion 350 of the drive gear 35. The drive cover portion 900 also covers the drive gear portion 350.

The first driven cover part 901 is connected to the driving cover part 900. The first driven cover part 901 also covers the first driven gear part 310.

The second driven cover part 902 is connected to the driving cover part 900 and the first driven cover part 901. The second driven cover part 902 also covers the second driven gear part 320.

The cover protrusion 903 is formed in a shape corresponding to the cover recess 364 of the driving gear part 350. The cover protrusion 903 also protrudes from the driving cover part 900 in the axial direction Da. The cover protrusion 903 is inserted into a space defined by the cover recess side surface 366 and the cover recess bottom surface 367 of the cover recess 364. The cover recess bottom surface 367 also supports the protective cover 90 by contacting the cover protrusion 903. Furthermore, when the driving gear 35 rotates, the cover recess bottom surface 367 slides on the end surface of the cover protrusion 903.

A part of the cover pin 44 is inserted into the cover hole 904. This makes it difficult for the protective cover 90 to come off from the case 40. In addition, because the protective cover 90 and the cover pin 44 are heat-sealed or the like, the protective cover 90 is less likely to come off from the case 40 compared to a case where heat-sealing or the like is not performed.

The torque angle sensor 25 is configured as described above. Next, we will explain how the torque angle sensor 25 detects steering torque.

Suppose that the steering wheel 5 is not rotating and therefore no steering torque is generated. In this case, as shown in FIG. 12, the torque detection magnet 30, the first yoke claw portion 372, and the second yoke claw portion 382 are phase-aligned in a neutral state in the circumferential direction. In this neutral state, the center positions of all the first yoke claw portions 372 and the second yoke claw portions 382 coincide with the boundary between the north pole and the south pole of the torque detection magnet 30 in the circumferential direction. At this time, the number of magnetic field lines passing from the north pole of the torque detection magnet 30 through the first yoke claw portion 372 is the same as the number of magnetic field lines passing from the north pole of the torque detection magnet 30 through the second yoke claw portion 382. Therefore, no magnetic flux density is generated between the first yoke 361 and the second yoke 362.

When the steering wheel 5 rotates, a steering torque is generated, causing the first steering shaft 11 connected to the steering wheel 5 to rotate. The torsion bar 13 fixed to the first steering shaft 11 by the shaft pin 14 also rotates. The second steering shaft 12 fixed to the torsion bar 13 by the shaft pin 14 also rotates. The second steering shaft 12 is also connected to the fixing collar 354 of the main driving gear 35. This causes the main driving gear 35 to rotate. As a result, the first yoke 361 and the second yoke 362 of the main driving gear 35 rotate relative to the torque detection magnet 30.

In this case, as shown in FIG. 13, the area where the N pole of the torque detection magnet 30 and the first yoke claw portion 372 overlap in the direction perpendicular to the axial direction Da increases. Also, the area where the S pole of the torque detection magnet 30 and the second yoke claw portion 382 overlap in the direction perpendicular to the axial direction Da increases. At this time, the magnetic field lines from the N pole of the torque detection magnet 30 toward the first yoke claw portion 372 increase, and the magnetic field lines from the second yoke claw portion 382 toward the S pole of the torque detection magnet 30 increase. As a result, magnetic flux density is generated between the first yoke 361 and the second yoke 362.

As described above, as shown in FIG. 10, the first magnetic induction member 71 is made of a soft magnetic material and faces the first yoke annular portion 370 and the first torque magnetic detection portion 61 in the axial direction Da. As described above, the second magnetic induction member 72 is made of a soft magnetic material and faces the first torque magnetic detection portion 61 and the second yoke annular portion 380 in the axial direction Da.

At this time, the magnetic field lines passing from the north pole of the torque detection magnet 30 through the first yoke annular portion 370 and the first magnetic induction member 71 to the first torque magnetic detection unit 61 increase. Furthermore, the magnetic field lines passing through the first torque magnetic detection unit 61 pass through the second magnetic induction member 72 and the second yoke annular portion 380 to the south pole of the torque detection magnet 30.

The first torque magnetic detection unit 61 therefore detects the strength of the magnetic field in one direction of the axial direction Da. As a result, the first torque magnetic detection unit 61 detects the steering torque. The first torque magnetic detection unit 61 also outputs a signal corresponding to the strength of the detected magnetic field to the motor control device 18 via the terminal 85. The motor control device 18 calculates the steering torque based on the signal from the first torque magnetic detection unit 61.

When a steering torque in the opposite direction to that in FIG. 13 occurs, as shown in FIG. 14, the portion where the south pole of the torque detection magnet 30 and the first yoke claw portion 372 overlap in the direction perpendicular to the axial direction Da increases. Also, the portion where the north pole of the torque detection magnet 30 and the second yoke claw portion 382 overlap in the direction perpendicular to the axial direction Da increases. At this time, the magnetic field lines from the north pole of the torque detection magnet 30 toward the second yoke claw portion 382 increase, and the magnetic field lines from the first yoke claw portion 372 toward the south pole of the torque detection magnet 30 increase. As a result, magnetic flux density is generated between the first yoke 361 and the second yoke 362.

At this time, the magnetic field lines passing from the north pole of the torque detection magnet 30 through the second yoke annular portion 380 and the second magnetic induction member 72 to the first torque magnetic detection unit 61 increase. Furthermore, the magnetic field lines passing through the first torque magnetic detection unit 61 pass through the south pole of the torque detection magnet 30 through the first magnetic induction member 71 and the first yoke annular portion 370.

Therefore, the first torque magnetic detection unit 61 detects the strength of the magnetic field in the other direction of the axial direction Da. As a result, the first torque magnetic detection unit 61 detects the steering torque. The first torque magnetic detection unit 61 also outputs a signal corresponding to the strength of the detected magnetic field to the motor control device 18 via the terminal 85. The motor control device 18 calculates the steering torque based on the signal from the first torque magnetic detection unit 61.

As described above, the torque angle sensor 25 detects steering torque. The second torque magnetic detection unit 62 of the torque angle sensor 25 detects steering torque in the same manner as the first torque magnetic detection unit 61. Therefore, if the first torque magnetic detection unit 61 fails, the torque angle sensor 25 can detect steering torque using the second torque magnetic detection unit 62. Next, the detection of steering angle by the torque angle sensor 25 will be described.

When the steering wheel 5 rotates, the first steering shaft 11 connected to the steering wheel 5 rotates. Also, the torsion bar 13 fixed to the first steering shaft 11 by the shaft pin 14 rotates. Furthermore, the second steering shaft 12 fixed to the torsion bar 13 by the shaft pin 14 rotates. Also, the second steering shaft 12 is connected to the fixing collar 354 of the main driving gear 35. Therefore, the main driving gear 35 rotates. Therefore, the first driven gear 31 and the second driven gear 32 meshed with this main driving gear 35 rotate.

At this time, the first angle detection magnet 51 attached to the first driven gear 31 rotates. As a result, the magnetic field lines passing from the north pole of the first angle detection magnet 51 through the case base 41, the first angle magnetic detection unit 81, the case base 41, and the south pole of the first angle detection magnet 51 change periodically. As a result, the strength of the magnetic field in the first direction D1 applied to the first angle magnetic detection unit 81 changes periodically.

As described above, as shown in FIG. 8, in the initial state in which the steering wheel 5 is not rotating, one side of the first angle detection magnet 51 in the first direction D1 is magnetized to the N pole. Furthermore, in the initial state in which the steering wheel 5 is not rotating, the other side of the first angle detection magnet 51 in the first direction D1 is magnetized to the S pole. Therefore, in the initial state in which the steering wheel 5 is not rotating, the strength of the magnetic field in the first direction D1 applied to the first angle magnetic detection unit 81 is a predetermined value.

Therefore, as shown in FIG. 15, when the steering angle changes, the output waveform of the first element of the first angle magnetic detection unit 81 that detects the strength of the magnetic field in the first direction D1 becomes a cosine wave. Therefore, at this time, the first element of the first angle magnetic detection unit 81 outputs a signal consisting of a cosine wave corresponding to the rotation angle and steering angle of the first driven gear 31 to the rotation angle calculation unit 83. Also, when the steering angle changes, the output waveform of the second element of the first angle magnetic detection unit 81 that detects the strength of the magnetic field in the direction perpendicular to the first direction D1 becomes a sine wave. Therefore, at this time, the second element of the first angle magnetic detection unit 81 outputs a signal consisting of a sine wave corresponding to the rotation angle and steering angle of the first driven gear 31 to the rotation angle calculation unit 83. In addition, in FIG. 15, the output waveform of the first element of the first angle magnetic detection unit 81 for the steering angle is indicated by C1. Also, the output waveform of the second element of the first angle magnetic detection unit 81 for the steering angle is indicated by S1.

The second angle detection magnet 52 attached to the second driven gear 32 also rotates. As a result, the magnetic field lines passing from the north pole of the second angle detection magnet 52 through the case base 41, the second angle magnetic detection unit 82, the case base 41, and the south pole of the second angle detection magnet 52 change periodically. This causes the strength of the magnetic field in the second direction D2 applied to the second angle magnetic detection unit 82 to change periodically.

As described above, as shown in FIG. 9, in the initial state in which the steering wheel 5 is not rotating, one side of the second angle detection magnet 52 in the second direction D2 is magnetized to the N pole. Furthermore, in the initial state in which the steering wheel 5 is not rotating, the other side of the second angle detection magnet 52 in the second direction D2 is magnetized to the S pole. Therefore, in the initial state in which the steering wheel 5 is not rotating, the strength of the magnetic field in the second direction D2 applied to the second angle magnetic detection unit 82 is a predetermined value.

Therefore, as shown in FIG. 15, when the steering angle changes, the output waveform of the first element of the second angle magnetic detection unit 82 that detects the strength of the magnetic field in the second direction D2 becomes a cosine wave. Therefore, at this time, the first element of the second angle magnetic detection unit 82 outputs a signal consisting of a cosine wave corresponding to the rotation angle and steering angle of the second driven gear 32 to the rotation angle calculation unit 83. Also, when the steering angle changes, the output waveform of the second element of the second angle magnetic detection unit 82 that detects the strength of the magnetic field in the direction perpendicular to the second direction D2 becomes a sine wave. Therefore, at this time, the second element of the second angle magnetic detection unit 82 outputs a signal consisting of a sine wave corresponding to the rotation angle and steering angle of the second driven gear 32 to the rotation angle calculation unit 83. In addition, in FIG. 15, the output waveform of the first element of the second angle magnetic detection unit 82 for the steering angle is indicated by C2. Also, the output waveform of the second element of the second angle magnetic detection unit 82 for the steering angle is indicated by S2.

Then, the rotation angle calculation unit 83 calculates a value related to the steering angle based on the signals from the first and second elements of the first angle magnetic detection unit 81 and the signals from the first and second elements of the second angle magnetic detection unit 82.

For example, the rotation angle calculation unit 83 divides the value of the signal consisting of a sine wave of the second element of the first magnetic detection unit for angle 81 by the value of the signal consisting of a cosine wave of the first element of the first magnetic detection unit for angle 81. As a result, the rotation angle calculation unit 83 calculates the rotation angle of the first driven gear 31 by calculating the tangent value corresponding to the rotation angle of the first driven gear 31 as shown in FIG. 16. The rotation angle calculation unit 83 also divides the value of the signal consisting of a sine wave of the second element of the second magnetic detection unit for angle 82 by the value of the signal consisting of a cosine wave of the first element of the second magnetic detection unit for angle 82. As a result, the rotation angle calculation unit 83 calculates the rotation angle of the second driven gear 32 by calculating the tangent value corresponding to the rotation angle of the second driven gear 32. In addition, in FIG. 16, the rotation angle of the first driven gear 31 relative to the steering angle is indicated by θt1. The rotation angle of the second driven gear 32 relative to the steering angle is indicated by θt2.

Here, the number of second driven teeth 324 corresponding to the number of teeth of the second driven gear 32 is different from the number of first driven teeth 314 corresponding to the number of teeth of the first driven gear 31. Therefore, the period of the output waveform of the first element and the second element of the first magnetic detector for angle 81 is different from the period of the output waveform of the first element and the second element of the second magnetic detector for angle 82. Furthermore, the outputs of the first element and the second element of the first magnetic detector for angle 81 and the outputs of the first element and the second element of the second magnetic detector for angle 82 each correspond to the steering angle. Therefore, the difference between the rotation angle of the first driven gear 31 and the rotation angle of the second driven gear 32 corresponds to the steering angle.

Therefore, the rotation angle calculation unit 83 calculates the difference between the rotation angle of the first driven gear 31 and the rotation angle of the second driven gear 32, and calculates the steering angle from this calculated difference.

As described above, the torque angle sensor 25 detects the steering angle. Next, we will explain how to improve the detection accuracy of the steering angle by the torque angle sensor 25.

The torque angle sensor 25 includes a driving gear 35, a first driven gear 31, a first angle detection magnet 51, a first angle magnetic detector 81, and a case 40. The driving gear 35 rotates together with the steering wheel 5. The first driven gear 31 rotates together with the driving gear 35. The first angle detection magnet 51 rotates together with the first driven gear 31 while generating a magnetic field. The first angle magnetic detector 81 detects the strength of the magnetic field that changes as the first driven gear 31 rotates. The strength of the magnetic field corresponds to the steering angle of the steering wheel 5. The case 40 has a case base surface 411 and a driving recess 43. The case base surface 411 rotatably supports the first driven gear 31 by contacting the first driven gear 31 in the axial direction Da. The driving recess 43 includes a driving recess side surface 431. The main driving recess side surface 431 is connected to the inner peripheral edge of the case base surface 411 and is formed in the shape of a side surface of an arc column corresponding to the rotation trajectory of the main driving gear 35. The main driving gear 35 faces the main driving recess side surface 431 in a direction perpendicular to the axial direction Da. The steering wheel 5 corresponds to the detection object. The steering angle of the steering wheel 5 corresponds to the rotation angle of the detection object. The main driving gear 35 corresponds to the main driving rotor. The first driven gear 31 corresponds to the driven rotor. The first angle detection magnet 51 corresponds to the angle magnet. The first angle magnetic detection unit 81 corresponds to the angle detection unit. The main driving recess side surface 431 corresponds to the case side surface.

This allows the driving gear 35 to be attached to the driving recess 43 of the case 40 by moving it in a direction perpendicular to the axial direction Da. This makes it easier to adjust the position of the driving gear 35 in a direction perpendicular to the axial direction Da. This reduces the variation in the distance between the axis of the driving gear 35 and the axis of the first driven gear 31 in a direction perpendicular to the axial direction Da. Therefore, the positional variation of the first driven gear 31 that rotates together with the driving gear 35 is reduced, and the variation in the positional relationship between the first driven gear 31 and the first angle magnetic detection unit 81 is reduced. This improves the detection accuracy of the magnetic field strength by the first angle magnetic detection unit 81, thereby improving the detection accuracy of the steering angle.

The torque angle sensor 25 also provides the following advantages:

[1-1] The torque angle sensor 25 further includes a torque detection magnet 30, a first torque magnetic detection unit 61, and a second torque magnetic detection unit 62. The torque detection magnet 30 rotates together with the steering wheel 5 while generating a magnetic field. The first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 detect the strength of the magnetic field that changes as the steering wheel 5 and the main driving gear 35 rotate. The strength of this magnetic field corresponds to the steering torque of the steering wheel 5. The torque detection magnet 30 corresponds to the torque magnet. The first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 correspond to the torque detection units.

As described above, it is easier to adjust the position of the driving gear 35 in the direction perpendicular to the axial direction Da, which reduces variation in the positional relationship between the driving gear 35, the first torque magnetic detection unit 61, and the second torque magnetic detection unit 62. This improves the detection accuracy of the magnetic field strength by the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62, thereby improving the detection accuracy of the steering torque.

[1-2] The torque angle sensor 25 further includes a substrate 60 and a terminal 85. The substrate 60 is equipped with a first torque magnetic detector 61, a second torque magnetic detector 62, a first angle magnetic detector 81, and a second angle magnetic detector 82. The terminal 85 is connected to the motor control device 18. The terminal 85 is disposed on the substrate 60 between the first torque magnetic detector 61 and the second torque magnetic detector 62 and the first angle magnetic detector 81 and the second angle magnetic detector 82. The motor control device 18 corresponds to the outside of the rotation angle detection device.

Here, the first torque magnetic detector 61 and the second torque magnetic detector 62 are arranged between the terminal 85 and the first angle magnetic detector 81 and the second angle magnetic detector 82. Compared to this case, the above arrangement shortens the length of the wiring from the first angle magnetic detector 81 and the second angle magnetic detector 82 to the terminal 85. This allows the substrate 60 to be made smaller, and therefore the torque angle sensor 25 to be made more compact.

[1-3] The torque angle sensor 25 further includes a first driven gear 31, a first angle detection magnet 51, a first angle magnetic detector 81, a second driven gear 32, a second angle detection magnet 52, a second angle magnetic detector 82, a rotation angle calculator 83, and a substrate 60. The second driven gear 32 rotates together with the driving gear 35 and the first driven gear 31. The second angle magnetic detector 82 detects the strength of the magnetic field that changes as the second driven gear 32 rotates. The strength of the magnetic field corresponds to the steering angle of the steering wheel 5. The rotation angle calculator 83 calculates the steering angle of the steering wheel 5 based on the strength of the magnetic field detected by the first angle magnetic detector 81 and the strength of the magnetic field detected by the second angle magnetic detector 82. The substrate 60 is equipped with the first angle magnetic detector 81, the second angle magnetic detector 82, and the rotation angle calculator 83. The rotation angle calculation unit 83 is disposed between the first angle magnetic detection unit 81 and the second angle magnetic detection unit 82. The first driven gear 31 corresponds to the first driven rotor. The first angle detection magnet 51 corresponds to the first angle magnet. The first angle magnetic detection unit 81 corresponds to the first angle detection unit. The second driven gear 32 corresponds to the second driven rotor. The second angle detection magnet 52 corresponds to the second angle magnet. The second angle magnetic detection unit 82 corresponds to the second angle detection unit. The rotation angle calculation unit 83 corresponds to the angle calculation unit.

As a result, the length of the wiring from the first angle magnetic detection unit 81 to the rotation angle calculation unit 83 is shorter than when the second angle magnetic detection unit 82 is disposed between the rotation angle calculation unit 83 and the first angle magnetic detection unit 81. This allows the substrate 60 to be made smaller, thereby enabling the torque angle sensor 25 to be made more compact.

[1-4] The torque angle sensor 25 further includes a protective cover 90. The protective cover 90 has a drive cover portion 900. The drive cover portion 900 covers the drive gear 35.

The drive cover part 900 prevents the drive gear 35 from coming off the case 40 and falling.

[1-5] The protective cover 90 further includes a first driven cover part 901 and a second driven cover part 902. The first driven cover part 901 covers the first driven gear 31. The second driven cover part 902 covers the second driven gear 32.

The first driven cover part 901 prevents the first driven gear 31 from coming off the case 40 and falling. The second driven cover part 902 prevents the second driven gear 32 from coming off the case 40 and falling.

[1-6] The driving gear 35 has a cover recess 364. The cover recess 364 is recessed in the axial direction Da from a surface facing the driving cover part 900 in the axial direction Da. The protective cover 90 has a cover protrusion 903. The cover protrusion 903 protrudes in the axial direction Da from the driving cover part 900. The cover recess 364 also includes a cover recess bottom surface 367 and a cover recess side surface 366 connected to the cover recess bottom surface 367. The cover protrusion 903 supports the driving gear 35 by being inserted into a space defined by the cover recess bottom surface 367 and the cover recess side surface 366. The cover recess 364 corresponds to the rotor recess. The cover recess side surface 366 corresponds to the rotor recess side surface. The cover recess bottom surface 367 corresponds to the rotor recess bottom surface. The cover protrusion 903 corresponds to the cover protrusion.

This supports the main driving gear 35, improving the positional accuracy of the main driving gear 35, and therefore improving the positional accuracy between the main driving gear 35 and the first driven gear 31.

Second Embodiment
In the second embodiment, the torque angle sensor 25 does not include a cover member 86 but includes a resin coating portion 87. The rest of the second embodiment is similar to the first embodiment.

As shown in FIG. 17, the resin coating portion 87 is formed by filling the board space 453 defined by the case base 41 and the case protrusion 45 with potting resin. As a result, the resin coating portion 87 covers the board 60 and the components mounted on the board 60, and also closes the board opening 454.

The second embodiment is configured as described above. The second embodiment also provides the same effects as the first embodiment.

Third Embodiment
The third embodiment differs from the first embodiment in the shape of the case 40. Also, in the third embodiment, the torque angle sensor 25 further includes an elastic member 88. Other than this, the third embodiment is similar to the first embodiment.

As shown in FIG. 18, the case 40 further has an elastic member recess 530. The elastic member recess 530 is a recess for attaching the elastic member 88 described below to the case protrusion 45. The elastic member recess 530 also has an elastic member recess side surface 531 and an elastic member recess bottom surface 532.

The elastic member recessed side surface 531 is connected to the case convex end surface 451. In addition, the elastic member recessed side surface 531 is formed in the shape of a cylindrical side surface.

The bottom surface 532 of the recess for the elastic member is connected to the side surface 531 of the recess for the elastic member. In addition, the bottom surface 532 of the recess for the elastic member is formed in a circular ring shape.

The elastic member 88 is made of rubber or the like, and is, for example, an O-ring or a C-ring. The elastic member 88 is inserted into a space defined by the elastic member recess side surface 531 and the elastic member recess bottom surface 532. The elastic member 88 is also elastically deformed by being sandwiched between the cover member 86 and the elastic member recess bottom surface 532. As a result, the elastic member 88 closes the gap between the cover member 86 and the case convex end surface 451.

The third embodiment is configured as described above. The third embodiment also provides the same effects as the first embodiment.

Fourth Embodiment
In the fourth embodiment, the configurations of the case 40 and the board 60 are different from those of the first embodiment. Also, in the fourth embodiment, the case 40 does not have the terminal housing portion 42, and a terminal case 89 is attached to the board 60. Other than these, the fourth embodiment is similar to the first embodiment.

As shown in FIG. 19, the case 40 does not have a terminal storage section 42, a cover pin 44, or a case protrusion 45, but has a case base 41, a driving recess 43, a first driven recess 401, a second driven recess 402, and a board pin 46. Of these, the driving recess 43, the first driven recess 401, the second driven recess 402, and the board pin 46 are formed in the same manner as in the first embodiment. However, the shape of the case base 41 is different from that of the first embodiment.

The case base 41 includes a first base 510, a first side 511, a second side 512, a third side 513 and a second base 514.

The first base 510 is formed in a plate shape extending in a direction perpendicular to the axis of the driving gear 35, and is formed in an arc shape centered on the axis of the driving gear 35. The first base 510 also has a driving recess 43, a first driven recess 401, and a second driven recess 402 formed therein. Therefore, the surface of the first base 510 is connected to the driving recess side surface 431, the first driven recess side surface 403, and the second driven recess side surface 405. Furthermore, a cover pin 44 and a board pin 46 protrude from the first base 510.

The first side portion 511 is connected to the first base portion 510. The first side portion 511 is formed in the shape of a side surface of an arc column centered on the axis of the main driving gear 35.

The second side portion 512 is connected to the first base portion 510 and the first side portion 511. In addition, the second side portion 512 is formed in a rectangular shape.

The third side portion 513 is connected to the second side portion 512. The third side portion 513 is also connected to the drive recess bottom surface 432. Furthermore, since the drive recess bottom surface 432 is formed in an arc shape, the third side portion 513 is formed in the side shape of an arc column centered on the axis of the drive gear 35.

The second base 514 is formed in a plate shape extending in a direction perpendicular to the axis of the driving gear 35 and in an arc shape centered on the axis of the driving gear 35. The second base 514 is connected to the side of the first side 511 opposite the first base 510, the side of the second side 512 opposite the first base 510, and the third side 513.

As shown in FIG. 19 and FIG. 20, a space for board 457 is formed, which is defined by the first base 510, the first side 511, the second side 512, the third side 513, and the second base 514. This space for board 457 is in an arc shape due to the shape of the first base 510, the first side 511, the second side 512, the third side 513, and the second base 514. In addition, a board opening 458 is formed, which is defined by the first side 511, the third side 513, and the second base 514. This board opening 458 is open toward the circumferential direction of the axis of the main driving gear 35. Furthermore, a terminal opening 459 is formed, which is defined by the first base 510 and the first side 511. This terminal opening 459 is a space that opens toward the axial direction Da, and is connected to the space for board 457 and the board opening 458.

The substrate 60 is formed in a shape corresponding to the substrate space 457 defined by the first base 510, the first side 511, the second side 512, the third side 513, and the second base 514. Therefore, the substrate 60 is formed in an arc-shaped plate shape centered on the axis of the driving gear 35. In addition, the substrate 60 is inserted into the substrate space 457 through the substrate opening 458 by rotating it in the circumferential direction.

The terminal case 89 is formed into a cylindrical shape from resin or the like. The terminal case 89 protrudes from the board 60 in the axial direction Da. The terminal case 89 houses the terminals 85. The terminal case 89 is disposed on the board opening 458 side of the board 60. Therefore, the terminal case 89 passes through the terminal opening 459 as shown in FIG. 21.

The fourth embodiment is configured as described above. The fourth embodiment also provides the same effects as the first embodiment.

Fifth Embodiment
The fifth embodiment differs from the first embodiment in the configuration of the case 40 and the cover member 86. The rest is similar to the first embodiment.

As shown in FIG. 22, the case 40 does not have a case protrusion 45 or a board pin 46. The cover member 86 has a plate portion 860, a protrusion 861, and a board pin 866.

The plate portion 860 is formed in a plate shape extending in a direction perpendicular to the axial direction Da. The protrusion portion 861 protrudes from the plate portion 860 toward the case base 41. This forms a space 883 for a board that is partitioned by the plate portion 860 and the protrusion portion 861. The space 883 for a board and the first space 408 are separated by the case base 41. The space 883 for a board and the second space 409 are also separated by the case base 41. Furthermore, the protrusion portion 861 includes a convex end surface 862 and a convex side surface 863.

The convex end surface 862 is connected to the case base 41 by welding or the like. A board opening 884 is formed above the convex end surface 862, and is a space that opens toward the axial direction Da. The convex side surface 863 is connected to the plate portion 860 and the convex end surface 862.

The board pin 866 is a pin for attaching the board 60 to the cover member 86. The board pin 866 protrudes from the plate portion 860 in the axial direction Da, and is located within the board space 883 defined by the plate portion 860 and the protrusion 861. Furthermore, a portion of the board pin 46 is inserted into the board hole 601. This fixes the board 60 to the cover member 86.

The fifth embodiment is configured as described above. The fifth embodiment also provides the same effects as the first embodiment.

Sixth Embodiment
The sixth embodiment differs from the fifth embodiment in the form of a cover member 86. Also, in the sixth embodiment, the torque angle sensor 25 further includes an elastic member 88. Other than this, the sixth embodiment is similar to the first embodiment.

As shown in FIG. 23, the cover member 86 has a recess in the protrusion 861. The elastic member 88 is inserted into the recess in the protrusion 861. The elastic member 88 is also elastically deformed by being sandwiched between the cover member 86 and the case base 41. As a result, the elastic member 88 closes the gap between the cover member 86 and the case base 41.

The sixth embodiment is configured as described above. The sixth embodiment also provides the same effects as the first embodiment.

Seventh Embodiment
In the seventh embodiment, the torque angle sensor 25 does not include the second driven gear 32, as shown in Figs. 24 and 25. Therefore, the torque angle sensor 25 does not include the second angle magnetic detector 82. The case 40 does not have the second driven recess 402. As shown in Figs. 26 and 27, the torque angle sensor 25 includes a first receiving coil 701, a second receiving coil 702, an exciting coil 703, a high-frequency transmitting circuit 704, an output circuit 705, and a conductor 706. The rest of the components are the same as those of the first embodiment. In Figs. 24 and 25, the first yoke 361, the second yoke 362, and the protective cover 90 are omitted in order to avoid complication of the description. In Fig. 26, the conductor 706 is omitted in order to avoid complication of the description.

The first receiving coil 701, the second receiving coil 702, and the excitation coil 703 are formed as shown in FIG. 26. The high-frequency transmitting circuit 704 and the output circuit 705 are mounted on the substrate 60.

As shown in FIG. 27, the first receiving coil 701 has a first lead portion 711, a second lead portion 712, a first bent portion 721, a second bent portion 722, a third bent portion 723, and a fourth bent portion 724. The first lead portion 711 and the second lead portion 712 are formed in a straight line. The first bent portion 721, the second bent portion 722, the third bent portion 723, and the fourth bent portion 724 are formed in a sine wave shape of half a period. One end of the first bent portion 721 is connected to the first lead portion 711. The other end of the first bent portion 721 is connected to one end of the second bent portion 722. The other end of the second bent portion 722 is connected to one end of the third bent portion 723. The other end of the third bent portion 723 is connected to one end of the fourth bent portion 724. The other end of the fourth bent portion 724 is connected to the second lead portion 712.

The second receiving coil 702 has a third lead portion 713, a fourth lead portion 714, a fifth lead portion 715, a fifth bend portion 725, a sixth bend portion 726, a seventh bend portion 727, an eighth bend portion 728, a ninth bend portion 729, and a tenth bend portion 730. The third lead portion 713, the fourth lead portion 714, and the fifth lead portion 715 are formed in a straight line. The fifth bend portion 725, the seventh bend portion 727, the eighth bend portion 728, and the tenth bend portion 730 are formed in a sine wave shape of a quarter period. The sixth bend portion 726 and the ninth bend portion 729 are formed in a sine wave shape of a half period. In addition, one end of the fifth bend portion 725 is connected to the third lead portion 713. Furthermore, the other end of the fifth bend portion 725 is connected to one end of the sixth bend portion 726. The other end of the sixth bending portion 726 is connected to one end of the seventh bending portion 727. The other end of the seventh bending portion 727 is connected to one end of the fifth lead portion 715. The other end of the eighth bending portion 728 is connected to one end of the fifth lead portion 715. The other end of the eighth bending portion 728 is connected to one end of the ninth bending portion 729. The other end of the ninth bending portion 729 is connected to one end of the tenth bending portion 730. The other end of the tenth bending portion 730 is connected to the fourth lead portion 714.

The excitation coil 703 surrounds the first receiving coil 701 and the second receiving coil 702. The high-frequency transmission circuit 704 is connected to the excitation coil 703 and applies an AC voltage to the excitation coil 703. The output circuit 705 generates a signal corresponding to the steering angle based on the voltage from the first receiving coil 701 and the second receiving coil 702. The output circuit 705 also outputs the generated signal to the rotation angle calculation unit 83.

The conductor 706 is formed of, for example, a metal. The conductor 706 also has a conductor ring portion 707 and multiple conductor protrusions 708. The conductor ring portion 707 is formed in an annular shape as shown in Figs. 24 and 25. A part of the driving small diameter portion 353 is inserted into the hole of the conductor ring portion 707. The conductor protrusions 708 protrude from the conductor ring portion 707 in a direction perpendicular to the axial direction Da. The conductor protrusions 708 are also disposed at positions facing the first receiving coil 701 and the second receiving coil 702 in the axial direction Da. Furthermore, the multiple conductor protrusions 708 are arranged at a predetermined interval in the circumferential direction, so that a space is formed between adjacent conductor protrusions 708.

The seventh embodiment is configured as described above. Next, we will explain how the steering angle is detected by the torque angle sensor 25 in the seventh embodiment.

Here, the following terms are defined to explain the detection of the steering angle. As shown in FIG. 28, the region defined by the first bend 721 and the fourth bend 724 of the first receiving coil 701 is the first region R1. The region defined by the second bend 722 and the third bend 723 of the first receiving coil 701 is the second region R2. As shown in FIG. 29, the region defined by the fifth bend 725 and the tenth bend 730 of the second receiving coil 702 is the third region R3. The region defined by the sixth bend 726 and the ninth bend 729 of the second receiving coil 702 is the fourth region R4. The region defined by the fifth lead portion 715, the seventh bend 727 and the eighth bend 728 of the second receiving coil 702 is the fifth region R5. The size of the first region R1 is the same as the size of the second region R2. The size of the third region R3 is the same as the size of the fifth region R5. Furthermore, the size of the fourth region R4 is twice the size of the third region R3. Furthermore, the size of the fourth region R4 is twice the size of the fifth region R5. Furthermore, when a unidirectional current flows through the first receiving coil 701, the direction of the magnetic field passing through the first region R1 among the magnetic fields generated by the current flowing through the first bending portion 721 is the same as the direction of the magnetic field passing through the first region R1 among the magnetic fields generated by the current flowing through the fourth bending portion 724. Therefore, the winding direction of the first bending portion 721 is the same as the winding direction of the fourth bending portion 724. Furthermore, when a unidirectional current flows through the first receiving coil 701, the direction of the magnetic field passing through the second region R2 among the magnetic fields generated by the current flowing through the second bending portion 722 is the same as the direction of the magnetic field passing through the second region R2 among the magnetic fields generated by the current flowing through the third bending portion 723. Therefore, the winding direction of the second bending portion 722 is the same as the winding direction of the third bending portion 723. Furthermore, when a unidirectional current flows through the second receiving coil 702, the direction of the magnetic field generated by the current flowing through the fifth bending portion 725 and passing through the third region R3 is the same as the direction of the magnetic field generated by the current flowing through the tenth bending portion 730 and passing through the third region R3. Furthermore, when a unidirectional current flows through the second receiving coil 702, the direction of the magnetic field generated by the current flowing through the fifth bending portion 725 and passing through the third region R3 is the same as the direction of the magnetic field generated by the current flowing through the seventh bending portion 727 and passing through the fifth region R5. Furthermore, when a unidirectional current flows through the second receiving coil 702, the direction of the magnetic field generated by the current flowing through the fifth bending portion 725 and passing through the third region R3 is the same as the direction of the magnetic field generated by the current flowing through the eighth bending portion 728 and passing through the fifth region R5. Therefore, the winding direction of the fifth bending portion 725 is the same as the winding direction of the seventh bending portion 727, the eighth bending portion 728, and the tenth bending portion 730. Furthermore, when a unidirectional current flows through the second receiving coil 702, the direction of the magnetic field generated by the current flowing through the sixth bending portion 726 and passing through the fourth region R4 is the same as the direction of the magnetic field generated by the current flowing through the ninth bending portion 729 and passing through the fourth region R4. Therefore, the winding direction of the sixth bending portion 726 is the same as the winding direction of the ninth bending portion 729. Furthermore, when a unidirectional current flows through the second receiving coil 702, the direction of the magnetic field generated by the current flowing through the sixth bending portion 726 and passing through the fourth region R4 is opposite to the direction of the magnetic field generated by the current flowing through the fifth bending portion 725 and passing through the third region R3. Therefore, the winding direction of the fifth bending section 725, the seventh bending section 727, the eighth bending section 728, and the tenth bending section 730 is opposite to the winding direction of the sixth bending section 726 and the ninth bending section 729.

Then, the high frequency transmission circuit 704 applies an AC voltage of 1 to 5 MHz to the excitation coil 703. This generates a magnetic field in the axial direction Da that passes through the first region R1, the second region R2, the third region R3, the fourth region R4, and the fifth region R5. In addition, the AC voltage of the high frequency transmission circuit 704 changes the magnetic field in the axial direction Da that passes through the first region R1, the second region R2, the third region R3, the fourth region R4, and the fifth region R5, so that a voltage is generated in the first receiving coil 701 and the second receiving coil 702 by electromagnetic induction.

When the steering wheel 5 rotates, the first steering shaft 11 connected to the steering wheel 5 rotates. The torsion bar 13 fixed to the first steering shaft 11 by the shaft pin 14 rotates. The second steering shaft 12 fixed to the torsion bar 13 by the shaft pin 14 rotates. The second steering shaft 12 is connected to the fixing collar 354 of the main driving gear 35. This causes the main driving gear 35 to rotate. Therefore, the conductor 706 into which the main driving small diameter portion 353 of the main driving gear 35 is inserted rotates.

At this time, when the conductor protrusion 708 of the conductor 706 faces the first receiving coil 701 and the second receiving coil 702 in the axial direction Da, an eddy current is generated in the conductor protrusion 708. This eddy current cancels out the magnetic field in the axial direction Da that passes through the portion facing the conductor protrusion 708 and passes through the first region R1, the second region R2, the third region R3, the fourth region R4, and the fifth region R5.

As described above, the multiple conductor protrusions 708 are arranged at a predetermined interval in the circumferential direction, so that a space is formed between adjacent conductor protrusions 708. As a result, as the conductor 706 rotates, the size of the parts of the first region R1, second region R2, third region R3, fourth region R4, and fifth region R5 that face the conductor protrusions 708 changes periodically. Therefore, the magnetic flux applied to the first region R1 and second region R2 changes periodically, so the voltage generated in the first receiving coil 701 changes periodically. In addition, the magnetic flux applied to the third region R3, fourth region R4, and fifth region R5 changes periodically, so the voltage generated in the second receiving coil 702 changes periodically.

The voltage generated in the first receiving coil 701 and the second receiving coil 702 is therefore a voltage obtained by multiplying the voltage generated by the magnetic field that changes due to the AC voltage from the high frequency transmission circuit 704 by the voltage that changes periodically due to the rotation of the conductor 706. Therefore, the voltage generated in the first receiving coil 701 and the second receiving coil 702 has a beat waveform that corresponds to the steering angle, as shown in FIG. 30. In FIG. 30, the AC voltage applied from the high frequency transmission circuit 704 to the excitation coil 703 is indicated by V0. The voltage generated in the first receiving coil 701 is indicated by V1. The voltage generated in the second receiving coil 702 is indicated by V2.

Here, for example, in the initial state, as shown in Figures 31 and 32, the central portions of the first receiving coil 701 and the second receiving coil 702 overlap one conductor protrusion 708.

At this time, the magnetic field passing through the portion of the first region R1 of the first receiving coil 701 that overlaps with the conductor convex portion 708 and the portion of the second region R2 that overlaps with the conductor convex portion 708 is offset by the eddy current generated in the conductor convex portion 708. In addition, the size of the portion of the first region R1 that overlaps with the conductor convex portion 708 is the same as the size of the portion of the second region R2 that overlaps with the conductor convex portion 708. Furthermore, as described above, the size of the first region R1 is the same as the size of the second region R2. Therefore, the size of the portion of the first region R1 that does not overlap with the conductor convex portion 708 is the same as the size of the portion of the second region R2 that does not overlap with the conductor convex portion 708. In addition, a voltage is generated in the first curved portion 721 and the fourth curved portion 724 by the magnetic field passing through the portion of the first region R1 that does not overlap with the conductor convex portion 708. Furthermore, a voltage is generated in the second bending portion 722 and the third bending portion 723 by a magnetic field passing through a portion of the second region R2 that does not overlap with the conductor convex portion 708. The winding direction of the first bending portion 721 and the fourth bending portion 724 is opposite to the winding direction of the second bending portion 722 and the third bending portion 723. Therefore, the direction of the voltage generated in the first bending portion 721 is opposite to the direction of the voltage generated in the second bending portion 722. The direction of the voltage generated in the fourth bending portion 724 is opposite to the direction of the voltage generated in the third bending portion 723. Furthermore, since the size of the portion of the first region R1 that does not overlap with the conductor convex portion 708 is the same as the size of the portion of the second region R2 that does not overlap with the conductor convex portion 708, the magnitude of the voltage generated in the first bending portion 721 is the same as the magnitude of the voltage generated in the second bending portion 722. Furthermore, the magnitude of the voltage generated in the fourth bending portion 724 is the same as the magnitude of the voltage generated in the third bending portion 723. Therefore, the voltage generated in the first bending portion 721 is offset by the voltage generated in the second bending portion 722. Furthermore, the voltage generated in the fourth bending portion 724 is offset by the voltage generated in the third bending portion 723. Therefore, in the initial state, the voltage generated in the first receiving coil 701 is zero.

The fourth region R4 of the second receiving coil 702 overlaps with the conductor convex portion 708. Therefore, the magnetic field passing through the fourth region R4 is offset by the eddy current generated in the conductor convex portion 708. Furthermore, a voltage is generated in the fifth bending portion 725 and the tenth bending portion 730 by the magnetic field passing through the third region R3. Furthermore, a voltage is generated in the seventh bending portion 727 and the eighth bending portion 728 by the magnetic field passing through the fifth region R5. Furthermore, the winding direction of the fifth bending portion 725 and the tenth bending portion 730 is the same as the winding direction of the seventh bending portion 727 and the eighth bending portion 728. Therefore, the direction of the voltage generated in the fifth bending portion 725 and the tenth bending portion 730 is the same as the direction of the voltage generated in the seventh bending portion 727 and the eighth bending portion 728. Therefore, in the initial state, the voltage generated in the second receiving coil 702 becomes a maximum value.

Then, the conductor protrusion 708 rotates so that the second region R2, the fourth region R4, and the fifth region R5 overlap with the conductor protrusion 708, as shown in Figures 33 and 34.

At this time, the magnetic field passing through the second region R2 is cancelled out by the eddy current generated in the conductor convex portion 708. Furthermore, a voltage is generated in the first curved portion 721 and the fourth curved portion 724 by the magnetic field passing through the first region R1. Furthermore, the winding direction of the first curved portion 721 is the same as the winding direction of the fourth curved portion 724. Therefore, the direction of the voltage generated in the first curved portion 721 is the same as the direction of the voltage generated in the fourth curved portion 724. Therefore, at this time, the voltage generated in the first receiving coil 701 becomes a maximum value.

In addition, the magnetic field passing through the portion of the fourth region R4 that overlaps with the conductor convex portion 708 and the fifth region R5 is offset by the eddy current generated in the conductor convex portion 708. In addition, the size of the portion of the fourth region R4 that overlaps with the conductor convex portion 708 is the same as the size of the fifth region R5. Furthermore, as described above, the size of the fifth region R5 is the same as the size of the third region R3. The size of the fourth region R4 is twice the size of the third region R3. Therefore, the size of the portion of the fourth region R4 that does not overlap with the conductor convex portion 708 is the same as the size of the third region R3. In addition, a voltage is generated in the sixth curved portion 726 and the ninth curved portion 729 by the magnetic field passing through the portion of the fourth region R4 that does not overlap with the conductor convex portion 708. In addition, a voltage is generated in the fifth curved portion 725 and the tenth curved portion 730 by the magnetic field passing through the third region R3. In addition, the winding direction of the sixth bending portion 726 and the ninth bending portion 729 is opposite to the winding direction of the fifth bending portion 725 and the tenth bending portion 730. Therefore, the direction of the voltage generated in the sixth bending portion 726 is opposite to the direction of the voltage generated in the fifth bending portion 725. In addition, the direction of the voltage generated in the ninth bending portion 729 is opposite to the direction of the voltage generated in the tenth bending portion 730. Furthermore, since the size of the portion of the fourth region R4 that does not overlap with the conductor convex portion 708 is the same as the size of the third region R3, the magnitude of the voltage generated in the sixth bending portion 726 is the same as the magnitude of the voltage generated in the fifth bending portion 725. In addition, the magnitude of the voltage generated in the ninth bending portion 729 is the same as the magnitude of the voltage generated in the tenth bending portion 730. Therefore, the voltage generated in the sixth bending portion 726 is offset by the voltage generated in the fifth bending portion 725. In addition, the voltage generated in the ninth bending section 729 is offset by the voltage generated in the tenth bending section 730. Therefore, at this time, the voltage generated in the second receiving coil 702 becomes zero.

Then, the conductor protrusion 708 rotates so that the first region R1, the second region R2, the third region R3, and the fifth region R5 overlap with the conductor protrusion 708, as shown in Figures 35 and 36.

At this time, the magnetic field passing through the portion of the first region R1 that overlaps with the conductor convex portion 708 and the portion of the second region R2 that overlaps with the conductor convex portion 708 is offset by the eddy current generated in the conductor convex portion 708. In addition, the size of the portion of the first region R1 that overlaps with the conductor convex portion 708 is the same as the size of the portion of the second region R2 that overlaps with the conductor convex portion 708. Furthermore, as described above, the size of the first region R1 is the same as the size of the second region R2. Therefore, the size of the portion of the first region R1 that does not overlap with the conductor convex portion 708 is the same as the size of the portion of the second region R2 that does not overlap with the conductor convex portion 708. In addition, a voltage is generated in the first curved portion 721 and the fourth curved portion 724 by the magnetic field passing through the portion of the first region R1 that does not overlap with the conductor convex portion 708. Furthermore, a voltage is generated in the second curved portion 722 and the third curved portion 723 by the magnetic field passing through the portion of the second region R2 that does not overlap with the conductor convex portion 708. In addition, the winding direction of the first bending portion 721 and the fourth bending portion 724 is opposite to the winding direction of the second bending portion 722 and the third bending portion 723. Therefore, the direction of the voltage generated in the first bending portion 721 is opposite to the direction of the voltage generated in the second bending portion 722. In addition, the direction of the voltage generated in the fourth bending portion 724 is opposite to the direction of the voltage generated in the third bending portion 723. Furthermore, since the size of the portion of the first region R1 that does not overlap with the conductor convex portion 708 is the same as the size of the portion of the second region R2 that does not overlap with the conductor convex portion 708, the magnitude of the voltage generated in the first bending portion 721 is the same as the magnitude of the voltage generated in the second bending portion 722. In addition, the magnitude of the voltage generated in the fourth bending portion 724 is the same as the magnitude of the voltage generated in the third bending portion 723. Therefore, the voltage generated in the first bending portion 721 is offset by the voltage generated in the second bending portion 722. In addition, the voltage generated in the fourth bending section 724 is offset by the voltage generated in the third bending section 723. Therefore, at this time, the voltage generated in the first receiving coil 701 becomes zero.

In addition, the third region R3 and the fifth region R5 overlap with the conductor convex portion 708. Therefore, the magnetic field passing through the third region R3 and the fifth region R5 is offset by the eddy current generated in the conductor convex portion 708. Furthermore, a voltage is generated in the sixth bend portion 726 and the ninth bend portion 729 by the magnetic field passing through the fourth region R4. Furthermore, the winding direction of the sixth bend portion 726 is the same as the winding direction of the ninth bend portion 729. Therefore, the direction of the voltage generated in the sixth bend portion 726 is the same as the direction of the voltage generated in the ninth bend portion 729. Furthermore, the winding direction of the sixth bend portion 726 and the ninth bend portion 729 is opposite to the winding direction of the fifth bend portion 725, the seventh bend portion 727, the eighth bend portion 728, and the tenth bend portion 730. As a result, the direction of the voltage generated in the sixth bend 726 and the ninth bend 729 is opposite to the direction of the voltage generated in the fifth bend 725, the seventh bend 727, the eighth bend 728, and the tenth bend 730. Therefore, the direction of the voltage generated in the sixth bend 726 and the ninth bend 729 is opposite to the direction of the voltage generated when the fourth region R4 overlaps with the conductor convex portion 708. Therefore, at this time, the voltage generated in the second receiving coil 702 becomes a minimum value.

Then, the conductor protrusion 708 rotates so that the first region R1, the third region R3, and the fourth region R4 overlap with the conductor protrusion 708, as shown in Figures 37 and 38.

At this time, the magnetic field passing through the first region R1 is offset by the eddy current generated in the conductor convex portion 708. In addition, a voltage is generated in the second bending portion 722 and the third bending portion 723 by the magnetic field passing through the second region R2. Furthermore, the winding direction of the second bending portion 722 is the same as the winding direction of the third bending portion 723. Therefore, the direction of the voltage generated in the second bending portion 722 is the same as the direction of the voltage generated in the third bending portion 723. In addition, the winding direction of the second bending portion 722 and the third bending portion 723 is opposite to the winding direction of the first bending portion 721 and the fourth bending portion 724. As a result, the direction of the voltage generated in the second bending portion 722 and the third bending portion 723 is opposite to the direction of the voltage generated in the first bending portion 721 and the fourth bending portion 724. Therefore, the direction of the voltage generated in the second bend 722 and the third bend 723 is opposite to the direction of the voltage generated when the second region R2 overlaps with the conductor convex portion 708. Therefore, at this time, the voltage generated in the first receiving coil 701 becomes a minimum value.

In addition, the magnetic field passing through the portion of the fourth region R4 that overlaps with the conductor convex portion 708 and the third region R3 is offset by the eddy current. In addition, the size of the portion of the fourth region R4 that overlaps with the conductor convex portion 708 is the same as the size of the third region R3. Furthermore, as described above, the size of the third region R3 is the same as the size of the fifth region R5. The size of the fourth region R4 is twice the size of the fifth region R5. Therefore, the size of the portion of the fourth region R4 that does not overlap with the conductor convex portion 708 is the same as the size of the fifth region R5. In addition, a voltage is generated in the sixth curved portion 726 and the ninth curved portion 729 by the magnetic field passing through the portion of the fourth region R4 that does not overlap with the conductor convex portion 708. In addition, a voltage is generated in the seventh curved portion 727 and the eighth curved portion 728 by the magnetic field passing through the fifth region R5. The winding direction of the sixth bending portion 726 and the ninth bending portion 729 is opposite to the winding direction of the seventh bending portion 727 and the eighth bending portion 728. Therefore, the direction of the voltage generated in the sixth bending portion 726 is opposite to the direction of the voltage generated in the seventh bending portion 727. The direction of the voltage generated in the ninth bending portion 729 is opposite to the direction of the voltage generated in the eighth bending portion 728. Furthermore, since the size of the portion of the fourth region R4 that does not overlap with the conductor convex portion 708 is the same as the size of the fifth region R5, the magnitude of the voltage generated in the sixth bending portion 726 is the same as the magnitude of the voltage generated in the seventh bending portion 727.
In addition, the magnitude of the voltage generated in the ninth bending portion 729 becomes the same as the magnitude of the voltage generated in the eighth bending portion 728. Therefore, the voltage generated in the sixth bending portion 726 is offset by the voltage generated in the seventh bending portion 727. In addition, the voltage generated in the ninth bending portion 729 is offset by the voltage generated in the eighth bending portion 728. Therefore, at this time, the voltage generated in the second receiving coil 702 becomes zero.

Then, the conductor protrusion 708 rotates, and the positional relationship between the first region R1, the second region R2, the third region R3, the fourth region R4, and the fifth region R5 becomes the same as in the initial state.

Therefore, when the steering angle changes, the voltage generated in the first receiving coil 701 becomes a sine wave, as shown in FIG. 30. Also, the voltage generated in the second receiving coil 702 becomes a cosine wave.

Therefore, the output circuit 705 detects the voltage generated in the first receiving coil 701 and divides the AC voltage applied to the first receiving coil 701 by the high frequency transmission circuit 704 from the detected voltage. As a result, the output circuit 705 generates a signal consisting of a sine wave corresponding to the steering angle by demodulation. The output circuit 705 also outputs the generated signal to the rotation angle calculation unit 83. Furthermore, the output circuit 705 detects the voltage generated in the second receiving coil 702 and divides the AC voltage applied to the second receiving coil 702 by the high frequency transmission circuit 704 from the detected voltage. As a result, the output circuit 705 generates a signal consisting of a cosine wave corresponding to the steering angle by demodulation. The output circuit 705 also outputs the generated signal to the rotation angle calculation unit 83.

Then, the rotation angle calculation unit 83 calculates a value related to the steering angle based on the signals from the first and second elements of the first angle magnetic detection unit 81 and the signal from the output circuit 705.

For example, the rotation angle calculation unit 83 divides the value of the signal consisting of a sine wave of the second element of the first magnetic angle detection unit 81 by the value of the signal consisting of a cosine wave of the first element of the first magnetic angle detection unit 81. As a result, the rotation angle calculation unit 83 calculates the rotation angle of the first driven gear 31 by calculating the tangent value corresponding to the rotation angle of the first driven gear 31. The rotation angle calculation unit 83 also divides the value of the signal consisting of a sine wave of the output circuit 705 by the value of the signal consisting of a cosine wave of the output circuit 705. As a result, the rotation angle calculation unit 83 calculates the rotation angle of the main gear 35 by calculating the tangent value corresponding to the rotation angle of the main gear 35.

As described above, the number of first driven teeth 314 corresponding to the number of teeth of the first driven gear 31 is different from the number of drive teeth 365 corresponding to the number of teeth of the drive gear 35. Therefore, the period of the output waveform of the first element and the second element of the first angle magnetic detection unit 81 is different from the period of the output waveform of the output circuit 705. Furthermore, the outputs of the first element and the second element of the first angle magnetic detection unit 81 and the output of the output circuit 705 each correspond to the steering angle. Therefore, the difference between the rotation angle of the first driven gear 31 and the rotation angle of the drive gear 35 corresponds to the steering angle.

Therefore, the rotation angle calculation unit 83 calculates the difference between the rotation angle of the first driven gear 31 and the rotation angle of the main driving gear 35, and calculates the steering angle from this calculated difference.

As described above, the torque angle sensor 25 detects the steering angle. In the seventh embodiment, the driving gear 35 can be attached to the driving recess 43 of the case 40 by moving the driving gear 35 in a direction perpendicular to the axial direction Da. This makes it easier to adjust the position of the driving gear 35 in a direction perpendicular to the axial direction Da, and therefore easier to adjust the position of the conductor 706 that rotates with the driving gear 35. This reduces the variation in the positional relationship between the conductor 706 and the first and second receiving coils 701 and 702. Therefore, the variation in the voltage generated in the first and second receiving coils 701 and 702 is reduced, improving the detection accuracy of the voltage by the output circuit 705, and thus improving the detection accuracy of the steering angle. Therefore, the seventh embodiment also has the same effects as the first embodiment. In addition, the seventh embodiment also has the effects described below.

[2] The torque angle sensor 25 includes a driving gear 35, a first receiving coil 701, a second receiving coil 702, an excitation coil 703, a high-frequency transmission circuit 704, a conductor 706, and a case 40. The driving gear 35 rotates together with the steering wheel 5. The first receiving coil 701 generates a voltage by electromagnetic induction. The second receiving coil 702 generates a voltage by electromagnetic induction. The excitation coil 703 surrounds the first receiving coil 701 and the second receiving coil 702. The high-frequency transmission circuit 704 applies an AC voltage to the excitation coil 703 to generate a magnetic field in the first region R1 and the second region R2 of the first receiving coil 701 and in the third region R3, the fourth region R4, and the fifth region R5 of the second receiving coil 702. The conductor 706 rotates together with the driving gear 35 to change the magnetic field passing through the first region R1, the second region R2, the third region R3, the fourth region R4, and the fifth region R5. As a result, the conductor 706 changes the voltage generated in the first receiving coil 701 and the second receiving coil 702. The output circuit 705 detects the voltage that changes as the conductor 706 rotates. This voltage corresponds to a value related to the steering angle. The case 40 is configured in the same manner as in the first embodiment. The driving gear 35 corresponds to the rotating body. The high-frequency transmission circuit 704 corresponds to the magnetic field generating unit. The output circuit 705 corresponds to the detection unit. The first region R1 and the second region R2 correspond to the inside of the first receiving coil 701. The third region R3, the fourth region R4, and the fifth region R5 correspond to the inside of the second receiving coil 702.

This makes it possible to eliminate the second driven gear 32 and the second magnet for angle detection 52, compared to the first embodiment.

Eighth embodiment
The eighth embodiment is a combination of the fifth and seventh embodiments. Specifically, the torque angle sensor 25 does not include the second driven gear 32. Therefore, the torque angle sensor 25 does not include the second magnetic detector 82. The case 40 does not include the second driven recess 402. As shown in FIG. 39, the torque angle sensor 25 includes the first receiving coil 701, the second receiving coil 702, the excitation coil 703, the high-frequency transmitting circuit 704, the output circuit 705, and the conductor 706, which are the same as those described above. The rest of the eighth embodiment is the same as the fifth embodiment. The eighth embodiment also provides the same effects as the seventh embodiment. In FIG. 39, the conductor 706 is omitted to avoid complication of description.

Ninth embodiment
The ninth embodiment is different from the first embodiment in the shape of the case 40. Other than this, the ninth embodiment is similar to the first embodiment.

As shown in FIG. 40, the case 40 is divided into two parts by having a first case 461 and a second case 462. In addition, the case 40 does not have a case protrusion 45. Note that in FIG. 40, the first yoke 361 and the second yoke 362 are omitted to avoid complexity of description.

The first case 461 includes the driving recess 43, the first driven recess 401, the second driven recess 402, and the cover pin 44. The first case 461 also includes an opening 465. This opening 465 opens in a direction perpendicular to the axial direction Da.

The second case 462 includes the case base 41, the terminal storage section 42, the case protrusion 45, and the board pins 46. Furthermore, the second case 462 is inserted into the space of the opening 465 of the first case 461 and is detachable from the first case 461.

The ninth embodiment is configured as described above. The ninth embodiment also provides the same effects as the first embodiment. The ninth embodiment also provides the effects described below.

[3] The torque angle sensor 25 further includes a substrate 60 on which a first magnetic detector 81 for angle is mounted. The case 40 has a first case 461 and a second case 462. The first case 461 includes the above-mentioned driving recess 43 and an opening 465. The opening 465 opens in a direction perpendicular to the axial direction Da. The second case 462 houses the substrate 60. The second case 462 is inserted into the opening 465 of the first case 461 in a direction perpendicular to the axial direction Da, and is detachable from the first case 461. The opening direction of the opening 465, which is perpendicular to the axial direction Da, corresponds to one direction.

Because the first case 461 and the second case 462 are detachably separated, the portion of the case 40 housing the substrate 60 can be easily removed. This makes it easy to replace the substrate 60.

Tenth embodiment
In the tenth embodiment, the torque angle sensor 25 does not include the cover pin 44 and the protective cover 90, but includes a holding pin 94 and a holding member 95. Also, the shape of the case 40 is different from that of the first embodiment. Other than these, the tenth embodiment is similar to the first embodiment.

The retaining pin 94 is a pin for attaching the retaining member 95, which will be described later, to the case 40. As shown in Figures 41 and 42, the retaining pin 94 protrudes from the case base 41 in a direction perpendicular to the axial direction Da.

The retaining member 95 is a member that is attached to the driving gear 35 and the case 40. Specifically, the retaining member 95 has a retaining recess 950 and a connection portion 955.

The holding recess 950 includes a holding recess side surface 951 and a holding recess bottom surface 952. The holding recess side surface 951 is formed in the shape of a side surface of an arc column. Therefore, the holding recess side surface 951 has a shape corresponding to the outer side surfaces of the annular driving large diameter portion 351 and the driving convex portion 352. The holding recess bottom surface 952 is connected to the holding recess side surface 951. In addition, the holding recess bottom surface 952 is formed in an arc shape. Therefore, the holding recess bottom surface 952 has a shape corresponding to the end surface of the driving convex portion 352 facing the axial direction Da. Furthermore, the holding recess bottom surface 952 supports the driving gear 35 by contacting the driving convex portion 352. In addition, when the driving gear 35 rotates, the driving convex portion 352 slides on the holding recess bottom surface 952.

The connection portion 955 has a connection hole 956. A part of the retaining pin 94 is inserted into the connection hole 956. This connects the retaining member 95 to the case 40 and makes it difficult for the retaining member 95 to come off from the case 40. In addition, because the connection portion 955 and the retaining pin 94 are heat-sealed or the like, the retaining member 95 is less likely to come off from the case 40 compared to a case in which heat-sealed or the like is not used.

The tenth embodiment is configured as described above. In the tenth embodiment, the main gear 35 can be attached to the recess of the case 40 by moving it in a direction perpendicular to the axial direction Da before attaching the retaining member 95. This makes it easier to adjust the position of the main gear 35 in the direction perpendicular to the axial direction Da. This provides the same effects as the first embodiment. The tenth embodiment also provides the effects described below.

[4] The torque angle sensor 25 further includes a holding member 95. The holding member 95 is connected to the case 40 and sandwiches the main driving gear 35 in a direction perpendicular to the axial direction Da. The holding member 95 also has a holding recess 950. The holding recess 950 includes a holding recess side surface 951 and a holding recess bottom surface 952. The holding recess side surface 951 is formed in the side shape of an arc column corresponding to the rotation trajectory of the main driving gear 35. The holding recess bottom surface 952 is connected to the holding recess side surface 951 and is formed in an arc shape corresponding to the rotation trajectory of the main driving gear 35. The holding recess bottom surface 952 is in contact with the main driving gear 35 in the axial direction Da, thereby rotatably supporting the main driving gear 35.

This retaining member 95 prevents the main driving gear 35 from coming off and falling from the case 40. In addition, because the main driving gear 35 is supported by this retaining member 95, the positional accuracy of the main driving gear 35 is improved, and therefore the positional accuracy between the main driving gear 35 and the first driven gear 31 is improved.

Eleventh Embodiment
In the eleventh embodiment, as shown in Figs. 43 to 46, the torque angle sensor 25 does not include the second driven gear 32. Therefore, the torque angle sensor 25 does not include the second angle magnetic detector 82. Furthermore, the torque angle sensor 25 does not include the first torque magnetic detector 61, the second torque magnetic detector 62, the support member 70, the first magnetic induction member 71, the second magnetic induction member 72, and the rotation angle calculator 83. Furthermore, the case 40 does not include the second driven recess 402. Furthermore, the driving gear 35 does not include the first yoke 361 and the second yoke 362. Furthermore, the torque angle sensor 25 includes the first receiver coil 741, the second receiver coil 742, the third receiver coil 743, the fourth receiver coil 744, the first excitation coil 751, and the second excitation coil 752. Furthermore, the torque angle sensor 25 includes a first high frequency transmission circuit 761, a second high frequency transmission circuit 762, a first conductor 771, a second conductor 772, a first output circuit 781 and a second output circuit 782. Other than these, the torque angle sensor 25 is similar to the first embodiment. In Fig. 46, the terminal connection hole 84 is omitted to avoid complication.

The first receiving coil 741 generates a voltage through electromagnetic induction. The second receiving coil 742 generates a voltage through electromagnetic induction. The first excitation coil 751 surrounds the first receiving coil 741 and the second receiving coil 742.

The third receiving coil 743 generates a voltage through electromagnetic induction. The fourth receiving coil 744 generates a voltage through electromagnetic induction. The second excitation coil 752 surrounds the third receiving coil 743 and the fourth receiving coil 744.

The first high frequency transmission circuit 761 generates a magnetic field in the first receiving coil 741 and the second receiving coil 742 by applying an AC voltage to the first excitation coil 751.

The second high frequency transmission circuit 762 generates a magnetic field in the third receiving coil 743 and the fourth receiving coil 744 by applying an AC voltage to the second excitation coil 752.

The first conductor 771 and the second conductor 772 are formed of, for example, metal. The first steering shaft 11 side of the torsion bar 13 is inserted into the hole of the first conductor 771. Therefore, as the torsion bar 13 rotates, the first conductor 771 is integrated with the main gear 35 by being integrally molded. Therefore, the first conductor 771 rotates together with the main gear 35. Furthermore, as the first conductor 771 rotates together with the torsion bar 13 and the main gear 35, the voltage generated in the first receiving coil 741 and the second receiving coil 742 changes.

The second steering shaft 12 side of the torsion bar 13 is inserted into the hole of the second conductor 772. Therefore, when the torsion bar 13 rotates, the second conductor 772 rotates together with the torsion bar 13, changing the voltage generated in the third receiving coil 743 and the fourth receiving coil 744.

The first output circuit 781 calculates the rotation angle of the first conductor 771 as shown in FIG. 47 based on the voltages generated in the first receiving coil 741 and the second receiving coil 742 that change due to the rotation of the first conductor 771. The first output circuit 781 also outputs a signal corresponding to the rotation angle of the first conductor 771 to the motor control device 18.

The second output circuit 782 calculates the rotation angle of the second conductor 772 based on the voltages generated in the third receiving coil 743 and the fourth receiving coil 744 that change due to the rotation of the second conductor 772. The second output circuit 782 also outputs a signal corresponding to the rotation angle of the second conductor 772 to the motor control device 18. In FIG. 47, the rotation angle of the second conductor 772 relative to the steering angle is indicated by θc1. The rotation angle of the second conductor 772 relative to the steering angle is indicated by θc2.

The motor control device 18 then calculates the steering torque by calculating the phase difference between the signal from the first output circuit 781 and the signal from the second output circuit 782 that occurs when steering torque is generated, as shown in FIG. 48. The motor control device 18 also calculates a value related to the steering angle based on the signals from the first and second elements of the first angle magnetic detection unit 81 and the signal from the first output circuit 781.

The eleventh embodiment is configured as described above. The eleventh embodiment also provides the same effects as the first embodiment.

Twelfth Embodiment
In the twelfth embodiment, the protective cover 90 does not have a cover protrusion 903, but has a cover recess 960 as shown in Fig. 49. Also, the driving gear 35 does not have a cover recess 364, but has a rotor protrusion 395. Other than these, it is the same as the first embodiment.

The cover recess 960 is recessed in the axial direction Da from the driving cover part 900. The cover recess 960 also includes a cover recess bottom surface 961 and a cover recess side surface 962 connected to the cover recess bottom surface 961.

The rotating body protrusion 395 protrudes in the axial direction Da from the surface facing the driving cover part 900 in the axial direction Da. The rotating body protrusion 395 also supports the protective cover 90 by being inserted into the space defined by the cover recess bottom surface 961 and the cover recess side surface 962.

The twelfth embodiment is configured as described above. The twelfth embodiment also provides the same effects as the first embodiment.

Other Embodiments
The present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. Furthermore, in each of the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where they are particularly clearly stated as essential or where they are clearly considered essential in principle.

The arithmetic unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the arithmetic unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the arithmetic unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by the computer.

In the above first to sixth, ninth, tenth and twelfth embodiments, the main driving gear 35 meshes with both the first driven gear 31 and the second driven gear 32, so that the rotation of the main driving gear 35 rotates the first driven gear 31 and the second driven gear 32. In contrast, the main driving gear 35 is not limited to meshing with both the first driven gear 31 and the second driven gear 32.

For example, the main driving gear 35 may mesh with the first driven gear 31, and the first driven gear 31 may mesh with the second driven gear 32. In this case, the rotation of the main driving gear 35 causes the first driven gear 31 to rotate. Furthermore, the rotation of the first driven gear 31 causes the second driven gear 32 to rotate.

For example, the main driving gear 35 may mesh with the second driven gear 32, which in turn may mesh with the first driven gear 31. In this case, the rotation of the main driving gear 35 causes the second driven gear 32 to rotate. Furthermore, the rotation of the second driven gear 32 causes the first driven gear 31 to rotate.

In the above embodiment, as shown in FIG. 50, an angle detection yoke 96 may be attached to the first driven small diameter portion 312 of the first driven gear 31. The angle detection yoke 96 is made of a soft magnetic material. The angle detection yoke 96 is arranged, for example, near the first angle detection magnet 51. At this time, the angle detection yoke 96 guides the magnetic field lines from the first angle detection magnet 51 to the case base 41. As a result, magnetic field lines are generated from the N pole of the first angle detection magnet 51, passing through the angle detection yoke 96, the case base 41, the first angle magnetic detection unit 81, the case base 41, the angle detection yoke 96, and the S pole of the first angle detection magnet 51. The angle detection yoke 96 guides the magnetic field lines from the first angle detection magnet 51 to the case base 41, so that the magnetic field lines passing through the first angle magnetic detection unit 81 become dense. Since the strength of the magnetic field applied to the first angle magnetic detector 81 is increased, the first angle magnetic detector 81 can easily detect the strength of the magnetic field corresponding to the steering angle. Furthermore, as described above, an angle detection yoke 96 may be attached to the second driven small diameter portion 322 of the second driven gear 32.

In the above embodiment, in the initial state in which the steering wheel 5 is not rotating, one side of the first direction D1 of the first angle detection magnet 51 is magnetized to the N pole. Furthermore, in the initial state in which the steering wheel 5 is not rotating, the other side of the first direction D1 of the first angle detection magnet 51 is magnetized to the S pole. However, the magnetization direction of the first angle detection magnet 51 is not limited to this. For example, the magnetization direction of the first angle detection magnet 51 may be the axial direction Da.

In this case, for example, as shown in FIG. 51, two first magnets 51 for angle detection are inserted into a space defined by the side surface 316 of the recess for the first magnet and the bottom surface 317 of the recess for the first magnet. One side of the axial direction Da of one first magnet 51 for angle detection is magnetized to the N pole. The other side of the axial direction Da of the first magnet 51 for angle detection is magnetized to the S pole. The other side of the axial direction Da of the other first magnet 51 for angle detection is magnetized to the N pole. The one side of the axial direction Da of the first magnet 51 for angle detection is magnetized to the S pole. As a result, a magnetic field line is generated from the N pole of the first magnet 51 for angle detection, passing through the case base 41, the first magnetic detection unit 81 for angle, the case base 41, and the S pole of the first magnet 51 for angle detection. Furthermore, similar to the above, the magnetization direction of the second magnet 52 for angle detection may be the axial direction Da.

In the first to sixth, ninth, tenth and twelfth embodiments, the rotation angle calculation unit 83 calculates the steering angle based on the signal from the first angle magnetic detection unit 81 and the signal from the second angle magnetic detection unit 82. In contrast, the rotation angle calculation unit 83 is not limited to calculating the steering angle based on the signal from the first angle magnetic detection unit 81 and the signal from the second angle magnetic detection unit 82. The rotation angle calculation unit 83 may calculate the steering angle based only on the signal from the first angle magnetic detection unit 81. The rotation angle calculation unit 83 may also calculate the steering angle based on the signal from the first angle magnetic detection unit 81 and the signal from the motor control device 18 according to the rotation angle of the motor 19. This makes it possible to eliminate the second driven gear 32 and the second angle detection magnet 52.

In the above embodiment, the first magnetic induction member 71 is supported by the support member 70 attached to the substrate 60. In contrast, the first magnetic induction member 71 is not limited to being supported by this support member 70. For example, the first magnetic induction member 71 may be attached to the case 40 and the cover member 86. In this case, the first magnetic induction member 71 is attached to the case 40 and the cover member 86 by, for example, insert molding or outsert molding. Furthermore, the second magnetic induction member 72 is attached to the surface of the substrate 60 opposite to the surface on which the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 are mounted. In contrast, the second magnetic induction member 72 is not limited to being attached to the substrate 60. For example, the second magnetic induction member 72 may be attached to the case 40 and the cover member 86. In this case, the second magnetic induction member 72 is attached to the case 40 and the cover member 86 by, for example, insert molding or outsert molding. In addition, the first magnetic induction member 71 and the second magnetic induction member 72 may not be required. In this case, the magnetic field lines from the torque detection magnet 30 pass through the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 via the first yoke 361. The magnetic field lines from the torque detection magnet 30 pass through the first torque magnetic detection unit 61 and the second torque magnetic detection unit 62 via the second yoke 362.

In addition, in the above embodiment, the number of teeth of the main gear 35, the number of teeth of the first driven gear 31, and the number of teeth of the second driven gear 32 are different from each other. The number of teeth of the main gear 35, the number of teeth of the first driven gear 31, and the number of teeth of the second driven gear 32 may be the same.

The third embodiment and the sixth embodiment may be combined. In this case, for example, as shown in FIG. 52, an elastic member 88 may be inserted into the recess of the protrusion 861 of the cover member 86. Also, as shown in FIG. 53, an elastic member 88 may be inserted into the recess of the case protrusion 45 of the case 40.

In the seventh and eighth embodiments, the first receiving coil 701 has a first lead portion 711, a second lead portion 712, a first bent portion 721, a second bent portion 722, a third bent portion 723, and a fourth bent portion 724. In contrast, the shape of the first receiving coil 701 is not limited to this. In addition, the second receiving coil 702 has a third lead portion 713, a fourth lead portion 714, a fifth lead portion 715, a fifth bent portion 725, a sixth bent portion 726, a seventh bent portion 727, an eighth bent portion 728, a ninth bent portion 729, and a tenth bent portion 730. In contrast, the shape of the second receiving coil 702 is not limited to this. For example, the shapes of the first receiving coil 701 and the second receiving coil 702 may be a shape that combines multiple straight lines, arcs, sine waves, cosine waves, etc., as shown in FIG. 54.

In the seventh and eighth embodiments, the rotation angle calculation unit 83 calculates the steering angle based on the signal from the first magnetic detection unit for angle 81 and the signal from the output circuit 705. In contrast, the rotation angle calculation unit 83 is not limited to calculating the steering angle based on the signal from the first magnetic detection unit for angle 81 and the signal from the output circuit 705. The rotation angle calculation unit 83 may calculate the steering angle based only on the signal from the first magnetic detection unit for angle 81. In addition, the rotation angle calculation unit 83 may calculate the steering angle based on the signal from the first magnetic detection unit for angle 81 and the signal from the motor control device 18 corresponding to the rotation angle of the motor 19. This makes it possible to eliminate the first receiving coil 701, the second receiving coil 702, the excitation coil 703, the high-frequency transmission circuit 704, the output circuit 705, and the conductor 706. Furthermore, the rotation angle calculation unit 83 may calculate the steering angle based only on the signal from the output circuit 705. The rotation angle calculation unit 83 may also calculate the steering angle based on a signal from the output circuit 705 and a signal corresponding to the rotation angle of the motor 19 from the motor control device 18. This makes it possible to eliminate the first driven gear 31 and the first angle detection magnet 51.

In the above embodiment, the substrate 60 is mounted with the first torque magnetic detection unit 61, the second torque magnetic detection unit 62, the first angle magnetic detection unit 81, the second angle magnetic detection unit 82, and the rotation angle calculation unit 83. The substrate 60 is also mounted with the first receiving coil 701, the second receiving coil 702, the excitation coil 703, the high-frequency transmission circuit 704, and the output circuit 705. In addition to these, the substrate 60 may also be mounted with a protective element.

In the above embodiment, the first yoke claw portion 372 and the second yoke claw portion 382 have a tapered shape. In contrast, the first yoke claw portion 372 and the second yoke claw portion 382 are not limited to having a tapered shape. For example, the first yoke claw portion 372 and the second yoke claw portion 382 may have a rectangular shape, etc.

In the above embodiment, the fixing collar 354 is connected to the second steering shaft 12, and the torque detection magnet 30 is connected to the first steering shaft 11. In contrast, the fixing collar 354 is not limited to being connected to the second steering shaft 12, and the torque detection magnet 30 is connected to the first steering shaft 11. For example, the fixing collar 354 may be connected to the first steering shaft 11, and the torque detection magnet 30 may be connected to the second steering shaft 12.

In the above embodiment, the case 40, protective cover 90, board 60, and terminal 85 may be formed by integral molding using resin. This allows the board 60 to be embedded in the resin, improving dustproofness and waterproofness.

In the above embodiment, the case 40 has a drive recess 43. However, the case 40 is not limited to having a drive recess 43. As shown in Figures 55 and 56, the drive recess 43 does not have to be formed. In this case, the case 40 has a side surface 471 connected to the inner peripheral edge of the case base surface 411. This side surface 471 corresponds to the case side surface and is formed in the side shape of a circular arc column centered on the axis of the drive gear 35. In addition, the side surface 471 faces the drive gear 35 in a direction perpendicular to the axial direction Da.

The above embodiments may also be combined as appropriate.

31 First driven gear 35 Main driving gear 40 Case 60 Substrate 61 First torque magnetic detection unit 62 Second torque magnetic detection unit 81 First angle magnetic detection unit 82 Second angle magnetic detection unit 83 Rotation angle calculation unit

Claims (12)

A rotation angle detection device for detecting a rotation angle of a detection object,
A driven rotor (35) that rotates together with the detection target;
A driven rotor (31) that rotates together with the driving rotor;
An angle magnet (51) that rotates together with the driven rotor while generating a magnetic field;
an angle detection unit (81) that detects the strength of a magnetic field that changes as the driven rotor rotates, corresponding to the rotation angle;
a case (40) having a case base (411) that rotatably supports the driven rotor by contacting the driven rotor in an axial direction (Da) of the driven rotor, and a case side surface (431, 471) that is connected to an inner peripheral edge of the case base and is formed into a side surface shape of an arc column that corresponds to a rotation trajectory of the driving rotor;
Equipped with
The driving rotor faces the side surface of the case in a direction perpendicular to the axial direction (Da) of the driving rotor. a torque magnet (30) that generates a magnetic field and rotates together with the detection target;
a torque detection unit (61, 62) that detects the strength of a magnetic field that changes as the detection object and the driving rotor rotate, corresponding to the torque of the detection object;
The rotation angle detection device according to claim 1 , further comprising: a substrate (60) on which the angle detection unit and the torque detection unit are mounted;
A terminal (85) connected to the outside of the rotation angle detection device;
Further equipped with
3. The rotation angle detection device according to claim 2, wherein the terminal is disposed on the board between the angle detection portion and the torque detection portion. The driven rotor is a first driven rotor,
The angle magnet is a first angle magnet,
The angle detection unit is a first angle detection unit,
The rotation angle detection device includes:
A second driven rotor (32) that rotates together with the driving rotor and the first driven rotor;
A second magnet for angle rotation (52) which rotates together with the second driven rotor while generating a magnetic field;
a second angle detection unit (82) that detects a strength of a magnetic field that corresponds to the rotation angle and changes as the second driven rotor rotates;
an angle calculation unit (83) that calculates the rotation angle based on the strength of the magnetic field detected by the first angle detection unit and the strength of the magnetic field detected by the second angle detection unit;
a substrate (60) on which the first angle detection unit, the second angle detection unit, and the angle calculation unit are mounted;
Further equipped with
4. The rotation angle detection device according to claim 1, wherein the angle calculation section is disposed between the first angle detection section and the second angle detection section. The angle detection unit further includes a substrate (60) on which the angle detection unit is mounted,
The case has a first case (461) and a second case (462),
The first case includes an opening (465) that opens in one direction,
3. The rotation angle detection device according to claim 1, wherein the second case is inserted into the opening (465) while accommodating the substrate, and is detachable from the first case. The rotation angle detection device according to any one of claims 1 to 5, further comprising a protective cover (90) having a drive cover portion (900) that covers the drive rotor. The driving rotor has a rotor recess (364) recessed in the axial direction (Da) of the driving rotor from a surface facing the driving cover part and the driving rotor in the axial direction (Da),
The protective cover has a cover protrusion (903) protruding from the driving cover portion in the axial direction (Da) of the driving rotor,
The rotor recess includes a rotor recess bottom surface (367) and a rotor recess side surface (366) connected to the rotor recess bottom surface,
7. The rotation angle detection device according to claim 6, wherein the cover protrusion supports the driving rotor by being inserted into a space defined by a bottom surface of the rotor recess and a side surface of the rotor recess. The protective cover has a cover recess (960) recessed from the driving cover portion in the axial direction (Da) of the driving rotor,
The driving rotor has a rotor protrusion (395) protruding in the axial direction (Da) of the driving rotor from a surface facing the driving cover part and the driving rotor in the axial direction (Da),
The cover recess includes a cover recess bottom surface (961) and a cover recess side surface (962) connected to the cover recess bottom surface,
The rotation angle detection device according to claim 6 , wherein the rotating body protrusion supports the protective cover by being inserted into a space defined by a bottom surface of the cover recess and a side surface of the cover recess. The rotation angle detection device according to any one of claims 6 to 8, wherein the protective cover further includes a driven cover portion (901) that covers the driven rotor. The vehicle further includes a holding member (95) that is connected to the case and that sandwiches the driving rotor in a direction perpendicular to the axial direction (Da) of the driving rotor,
The retaining member has a retaining recess (950);
The holding recess includes a holding recess side surface (951) formed in a side shape of a circular arc column corresponding to the rotation trajectory of the driving rotor, and a holding recess bottom surface (952) connected to the holding recess side surface and formed in an arc shape corresponding to the rotation trajectory of the driving rotor,
6. A rotation angle detection device according to claim 1, wherein a bottom surface of the holding recess rotatably supports the driving rotor by being in contact with the driving rotor in an axial direction (Da) of the driving rotor. A rotation angle detection device for detecting a rotation angle of a detection object,
A rotating body (35) that rotates together with the detection object;
A first receiving coil (701) that generates a voltage by electromagnetic induction;
A second receiving coil (702) that generates a voltage by electromagnetic induction;
an excitation coil (703) surrounding the first receiving coil and the second receiving coil;
a magnetic field generating unit (704) that generates a magnetic field inside the first receiving coil and the second receiving coil by applying an AC voltage to the excitation coil;
a conductor (706) that changes a magnetic field passing through the first receiving coil and the second receiving coil by rotating together with the rotating body, thereby changing a voltage generated in the first receiving coil and the second receiving coil;
A detection unit (705) that detects a voltage that corresponds to the rotation angle and changes as the conductor rotates;
A case (40) having a case base (411) facing the axial direction (Da) of the rotor, and a case side surface (431, 471) connected to an inner peripheral edge of the case base and formed in a side shape of a circular arc column corresponding to a rotation trajectory of the rotor;
Equipped with
A rotation angle detection device in which the rotating body faces the side surface of the case in a direction perpendicular to the axial direction (Da) of the rotating body. A driven rotor (31) that rotates together with the rotor;
An angle magnet (51) that rotates together with the driven rotor while generating a magnetic field;
an angle detection unit (81) that detects the strength of a magnetic field that changes as the driven rotor rotates, corresponding to the rotation angle;
The rotation angle detection device according to claim 11 , further comprising:

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