Magnetic yoke assembly and sensor device

Abstract

A magnetic yoke assembly (42) comprises: a pair of yoke cores (61, 62); an annular collar (63); and a cylindrical holder (64) that holds the yoke cores (61, 62) and the collar (63). The holder (64) has a gear (75) having a plurality of outer teeth (77) that project outside the holder (64) in a radial direction. The collar (63) is disposed on the inner circumferential side of the gear (75). The axial range of the holder (64) in which the collar (63) is present overlaps the axial range of the holder (64) in which the gear (75) is provided.

Description

Technical Field

[0001] The present disclosure relates to a magnetic yoke assembly and a sensor device.

Background Art

[0002] Conventionally, for example, as described in Patent Document 1, a sensor device used in a steering device is known. This sensor device is provided on the outer periphery of a steering shaft to which a steering wheel is connected, and detects both the steering torque input by a driver and the steering angle which is the rotation angle of the steering shaft.

[0003] Specifically, the steering shaft includes an input shaft, an output shaft, and a torsion bar that connects these input and output shafts to each other. The sensor device includes a sensor magnet fixed to the input shaft, a magnetic yoke assembly fixed to the output shaft, and a driven gear that rotates in response to the rotation of the magnetic yoke assembly. The sensor device detects the steering torque based on the magnetic flux flowing through the magnetic yoke assembly, and detects the steering angle based on the rotation angle of the driven gear.

[0004] Such a magnetic yoke assembly includes, for example, as described in Patent Document 2, a pair of yoke cores, an annular collar, and a cylindrical resin holder that holds these yoke cores and the collar. A collar is held at one axial end of the resin holder, and a gear portion that meshes with a driven gear is provided on the outer peripheral surface at the other axial end.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] There is a demand for miniaturization of the magnetic yoke assembly and the sensor device including the same as described above.

Means for Solving the Problem

[0007] In one aspect of the present disclosure, a magnetic yoke assembly is provided. The magnetic yoke assembly includes a pair of yoke cores, an annular collar, and a cylindrical holder that holds the pair of yoke cores and the collar. The holder has a gear portion having a plurality of external teeth protruding radially outward of the holder. The collar is disposed on the inner circumferential side of the gear portion. The axial range in which the collar exists in the holder overlaps with the axial range in which the gear portion is provided in the holder.

[0008] In another aspect of the present disclosure, a sensor device is provided. The sensor device includes a sensor magnet configured to rotate integrally with a first shaft, the magnetic yoke assembly configured to rotate integrally with a second shaft connected to the first shaft via a torsion bar, a pair of magnetic flux collecting members disposed at intervals on the outer peripheral side of the magnetic yoke assembly, a magnetic sensor that generates a signal according to the magnetic flux flowing through the pair of magnetic flux collecting members, a driven gear that rotates according to the rotation of the magnetic yoke assembly, and a rotation sensor that generates a signal according to the rotation angle of the driven gear.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] An embodiment in which the magnetic yoke assembly and the sensor device of the present disclosure are applied to a steering column device will be described with reference to the drawings. The steering column device 1 shown in FIG. 1 is generally mounted on the vehicle along the vehicle longitudinal direction. In the following description, the left side in FIG. 1 is defined as the front side of the vehicle, and the right side in FIG. 1 is defined as the rear side of the vehicle. Also, the directions represented by terms such as “front”, “rear”, “upper”, “lower”, “left”, and “right” are defined with reference to the vehicle.

[0011] (Overall Configuration) As shown in FIG. 1, the steering column device 1 includes a column shaft 2 and a steering column 3 that rotatably houses the column shaft 2. The column shaft 2 and the steering column 3 are arranged on a common axis L. The steering column device 1 also includes a sensor device 4 and an EPS actuator 5.

[0012] A steering wheel 6 is connected to the rear end of the column shaft 2. The front end of the column shaft 2 is connected to the steered wheels via a steering mechanism (not shown). Thereby, the steered wheels are steered according to the driver's steering operation.

[0013] The sensor device 4 outputs both a signal for detecting the steering torque input by the driver and a signal for detecting the steering angle, which is the rotation angle of the column shaft 2. The EPS actuator 5 includes a motor (not shown) and a speed reducer 7. The motor is controlled by a control device (not shown) so as to generate a torque corresponding to a signal including the signal output from the sensor device 4. The rotation of the motor is decelerated by the speed reducer 7 and transmitted to the column shaft 2. Thereby, the EPS actuator 5 applies an assist force for assisting the steering operation by the driver. The speed reducer 7 of the present embodiment is a worm reducer having a worm shaft 8 and a worm wheel 9, but is not limited thereto, and any other speed reducer may be used.

[0014] (Column shaft 2) The column shaft 2 includes an upper shaft 11 and a lower shaft 12. The upper shaft 11 has an elongated cylindrical shape. A steering wheel 6 is connected to the rear end portion of the upper shaft 11.

[0015] In this specification, the "cylindrical shape" only needs to be regarded as a cylindrical shape as a whole, and includes those formed by combining a plurality of parts into a cylindrical shape, or those having a notch or the like in part such as a C shape. The "cylindrical shape" includes, but is not limited to, a circular shape, an elliptical shape, and a polygon having sharp or rounded corners when viewed in the axial direction. In the present embodiment, the upper shaft 11 has a circular shape when viewed in the axial direction.

[0016] The lower shaft 12 includes an input shaft 13 which is a first shaft, an output shaft 14 which is a second shaft, and a torsion bar 15 which connects the input shaft 13 and the output shaft 14 to each other. The input shaft 13 has, for example, an elongated columnar shape. The input shaft 13 is fitted into the inner peripheral portion of the upper shaft 11 through spline engagement. Thereby, the input shaft 13 is connected to be integrally rotatable with the upper shaft 11 and axially movable with respect to the upper shaft 11. The input shaft 13 has a fixing hole 16 that opens at the front end portion.

[0017] The output shaft 14 has, for example, an elongated cylindrical shape. In the present embodiment, the output shaft 14 has a circular shape when viewed axially. The front end portion of the input shaft 13 is inserted into the rear end portion of the output shaft 14. A bearing 17 is provided between the outer peripheral surface of the front end portion of the input shaft 13 and the inner peripheral surface of the rear end portion of the output shaft 14. Thereby, the output shaft 14 rotatably supports the input shaft 13. A worm wheel 9 is fixed to the outer periphery of the output shaft 14.

[0018] The torsion bar 15 has, for example, an elongated columnar shape. The rear end portion of the torsion bar 15 is fitted into the fixing hole 16, thereby being integrally rotatably connected to the input shaft 13. The front end portion of the torsion bar 15 is fitted into the inner periphery of the front end portion of the output shaft 14, thereby being integrally rotatably connected to the output shaft 14. Thereby, the input shaft 13 and the output shaft 14 rotate relative to each other by twisting the torsion bar 15.

[0019] (Steering column 3) The steering column 3 includes an outer tube 21, an inner tube 22, and a housing 23.

[0020] The outer tube 21 has a cylindrical shape. The outer tube 21 rotatably supports the upper shaft 11 via a bearing 24. The inner tube 22 has a cylindrical shape that is thinner than the outer tube 21. In the present embodiment, the outer tube 21 and the inner tube 22 have a circular shape when viewed axially. The rear end portion of the inner tube 22 is fitted into the inner periphery of the outer tube 21. The front end portion of the inner tube 22 is fixed to the housing 23.

[0021] The steering column 3 of the present embodiment further includes a sleeve 25 disposed between the outer tube 21 and the inner tube 22. Here, for example, when an impact load due to a vehicle collision acts on the steering wheel 6, the outer tube 21 moves axially with respect to the inner tube 22 while deforming the sleeve 25. By contracting the steering column 3 in this way, the impact load is absorbed. In other embodiments, the front end of the inner tube may be directly fitted to the inner circumference of the outer tube. The length by which the steering column 3 contracts when an impact load acts on the steering wheel 6 is sometimes referred to as the EA stroke.

[0022] As shown in FIGS. 1 and 2, the housing 23 includes a housing body 31, a cover 32, and a partition plate 33. The housing body 31 has a cylindrical shape. In the present embodiment, the housing body 31 has a circular shape when viewed axially. The housing body 31 has an end wall at one end in the axial direction. In the illustrated example, the end wall is provided at the front end of the housing body 31. The end wall of the housing body 31 has a through hole 34 penetrating in the axial direction. The cover 32 has a disc shape. The cover 32 is fixed to the rear end of the housing body 31 so as to cover the opening of the housing body 31. The cover 32 has a through hole 35 penetrating in the axial direction. The partition plate 33 has a disc shape. The partition plate 33 is fixed to the inner peripheral surface of the housing body 31. Thereby, the space inside the housing body 31 is partitioned into a gear accommodation space S1 disposed on the front side and a sensor accommodation space S2 disposed on the rear side. The reduction gear 7 is accommodated in the gear accommodation space S1, and the sensor device 4 is accommodated in the sensor accommodation space S2. The partition plate 33 has a through hole 36 penetrating in the axial direction. The through holes 34 to 36 are all provided on the axis L. The housing 23 of the present embodiment rotatably supports the output shaft 14 via bearings 37 and 38 provided in the through holes 34 and 36. In other embodiments, for example, the input shaft 13 may be rotatably supported via a bearing provided in the through hole 35, and the support mode of the column shaft 2 by the housing 23 can be appropriately changed.

[0023] (Sensor device 4) As shown in FIGS. 2 and 3, the sensor device 4 includes a sensor magnet 41, a magnetic yoke assembly 42, a magnetic flux collecting unit 43, a gear unit 44, and a circuit board 45. The gear unit 44 includes two driven gears 46 and 47 that rotate in response to the rotation of the magnetic yoke assembly 42. The circuit board 45 includes a magnetic sensor 48 that generates a signal corresponding to the magnetic flux flowing through the magnetic flux collecting unit 43, and rotation sensors 49a and 49b that generate signals corresponding to the rotation angles of the driven gears 46 and 47. The signal output from the magnetic sensor 48 corresponds to the steering torque, and the signals output from the rotation sensors 49a and 49b correspond to the steering angle.

[0024] The sensor device 4 may output the signal itself output from the magnetic sensor 48 and / or the signal itself output from the rotation sensors 49a and 49b to the control device of the motor. Alternatively, the sensor device 4 may output the steering torque detected based on the signal output from the magnetic sensor 48 and / or the steering angle detected based on the signal output from the rotation sensors 49a and 49b to the control device of the motor.

[0025] Hereinafter, the components of the sensor device 4 will be described in detail. (Sensor magnet 41) The sensor magnet 41 is a ring magnet having a circular cylindrical shape when viewed in the axial direction. The sensor magnet 41 is magnetized along the radial direction so that magnetic poles of different polarities are alternately arranged in the circumferential direction. The sensor device 4 of the present embodiment includes a magnet holder 51, and the sensor magnet 41 is fixed to the outer peripheral surface of the input shaft 13 via the magnet holder 51. In other embodiments, the sensor magnet 41 may be directly fixed to the outer peripheral surface of the input shaft 13. Further, in another embodiment, the sensor magnet 41 may be a plurality of plate-shaped magnets.

[0026] (Magnetic yoke assembly 42) As shown in FIGS. 3 and 4, the magnetic yoke assembly 42 includes a pair of yoke cores 61, 62, a collar 63, and a holder 64 that holds the pair of yoke cores 61, 62 and the collar 63.

[0027] Each of the yoke cores 61, 62 is made of a magnetic material and has an annular shape. The yoke cores 61, 62 are arranged at an axial interval. The yoke cores 61, 62 each have ring portions 65, 66 and a plurality of claw portions 67, 68. The claw portions 67, 68 project from the corresponding ring portions 65, 66 in a direction approaching each other. The claw portions 67, 68 are provided at equal intervals in the circumferential direction, and the claw portions 67 and 68 are alternately arranged in the circumferential direction.

[0028] The term "annular" in this specification only needs to be regarded as annular as a whole, and includes those formed by combining a plurality of parts into an annular shape, or those having a notch or the like in part such as a C shape. The "annular" shape includes, but is not limited to, a circular shape, an elliptical shape, and a polygon having sharp or rounded corners when viewed in the axial direction. In the present embodiment, each of the yoke cores 61, 62 has a circular shape when viewed in the axial direction.

[0029] As shown in FIGS. 4 and 5, the collar 63 is made of, for example, a metal material and has an annular shape. In the present embodiment, the collar 63 has a circular shape when viewed in the axial direction. The collar 63 is arranged on the front side in the axial direction with respect to the pair of yoke cores 61, 62. The collar 63 is fitted to the outer periphery of the rear end portion of the output shaft 14. The collar 63 has an annular main body portion 71 that fits onto the output shaft 14 and a flange portion 72 that projects radially inward from the inner peripheral surface of the main body portion 71. The thickness of the main body portion 71 along the radial direction is thinner at the front end portion than at the rear end portion. The flange portion 72 is, for example, annular.

[0030] The flange portion 72 is provided at the rear end portion of the main body portion 71. In other words, the flange portion 72 is provided at the end portion of the main body portion 71 near the yoke cores 61 and 62. Therefore, when assembling the sensor device 4, the collar 63 is configured to be fitted to the output shaft 14 from the rear side. In other words, the collar 63 is configured to be fitted to the output shaft 14 by moving forward with respect to the output shaft 14. That is, the direction in which the collar 63 is fitted to the output shaft 14 is the direction along the axis of the holder 64 and facing the front side. The direction in which the collar 63 is fitted to the output shaft 14 is also referred to as the first direction.

[0031] The holder 64 is made of, for example, a resin material and has a cylindrical shape. In the present embodiment, the holder 64 has a circular shape when viewed in the axial direction. The axial direction of the holder 64 coincides with the direction along the axis L. The holder 64 of the present embodiment is integrated with the pair of yoke cores 61 and 62 and the collar 63 by insert molding. In other embodiments, the holder 64 may be molded as a single unit and then the yoke cores 61 and 62 and the collar 63 may be assembled to the holder 64. The holder 64 holds the pair of yoke cores 61 and 62 and the collar 63 on the axis L.

[0032] Specifically, the holder 64 has a yoke core holding portion 73 that holds the pair of yoke cores 61 and 62, a collar holding portion 74 that holds the collar 63, a gear portion 75, and an alignment portion 76.

[0033] The yoke core holding portion 73 holds the yoke cores 61 and 62 such that the inner surfaces of the claw portions 67 and 68 are exposed on the inner peripheral side of the holder 64. Further, the yoke core holding portion 73 holds the yoke cores 61 and 62 such that the outer peripheral edges of the ring portions 65 and 66 protrude radially outward from the holder 64.

[0034] The gear portion 75 is provided side by side with the yoke core holding portion 73 along the axial direction of the holder 64. The gear portion 75 is provided continuously, for example, on the front side of the yoke core holding portion 73. The gear portion 75 has a plurality of external teeth 77 protruding radially outward of the holder 64 and tooth grooves 78 between the plurality of external teeth 77. In the present embodiment, in the front end region in the axial direction of each external tooth 77, the tooth height decreases and the tooth thickness becomes thinner as it goes toward the front side. In other embodiments, the tooth height and tooth thickness of each external tooth 77 may be constant along the axial direction. The front end of each tooth groove 78 opens to the front side in the axial direction, and the rear end of each tooth groove 78 is closed by the ring portion 66 of the yoke core 62. That is, the tooth groove 78 opens in the direction of fitting the collar 63 onto the output shaft 14.

[0035] The collar holding portion 74 holds the collar 63 such that the inner peripheral surface of the collar 63 is exposed on the inner peripheral side of the holder 64. Further, the collar holding portion 74 of the present embodiment holds the collar 63 such that the front end portion of the main body portion 71 is exposed in the axial direction. In other embodiments, the front end portion of the main body portion 71 may be covered by the collar holding portion 74.

[0036] The collar holding portion 74 is provided on the inner peripheral side of the gear portion 75. That is, the collar 63 is provided on the inner peripheral side of the gear portion 75. And the axial range in which the collar 63 exists in the holder 64 overlaps with the axial range in which the gear portion 75 is provided in the holder 64. Specifically, the entire axial range in which the collar 63 exists in the holder 64 is included within the axial range in which the gear portion 75 is provided in the holder 64.

[0037] The alignment portion 76 is provided so as to protrude rearward in the axial direction from the yoke core holding portion 73. The alignment portion 76 has, for example, a fan shape when viewed from the axial direction. The alignment portion 76 has an alignment groove 79 penetrating radially through the center in the circumferential direction thereof. In the illustrated example, the holder 64 has two alignment portions 76, but the present invention is not limited thereto, and the holder 64 may have one or three or more alignment portions 76.

[0038] The magnetic yoke assembly 42 is fixed to rotate integrally with the output shaft 14 by press-fitting the collar 63 onto the rear end portion of the output shaft 14. With the magnetic yoke assembly 42 fixed to the output shaft 14, the magnetic yoke assembly 42 is disposed at a distance from the outer peripheral side of the sensor magnet 41. Further, the end face of the rear end portion of the output shaft 14 abuts against the flange portion 72.

[0039] (Magnetic flux collecting unit 43) As shown in FIGS. 2, 3, and 5, the magnetic flux collecting unit 43 includes a pair of magnetic flux collecting members 81, 82, a first support frame 83, and a second support frame 84.

[0040] Each of the magnetic flux collecting members 81, 82 is made of a magnetic material and has a C shape. The magnetic flux collecting member 81 has two protrusions 85 protruding in the radial direction, and the magnetic flux collecting member 82 has two protrusions 86 protruding in the radial direction. The magnetic flux collecting member 81 is disposed at a distance from the outer periphery of the yoke core 61, and the magnetic flux collecting member 82 is disposed at a distance from the outer periphery of the yoke core 62. That is, the magnetic flux collecting members 81, 82 are disposed at a distance in the axial direction. The magnetic flux flowing through the yoke core 61 is induced in the magnetic flux collecting member 81, and the magnetic flux flowing through the yoke core 62 is induced in the magnetic flux collecting member 82. The protrusion 85 and the protrusion 86 face each other in the axial direction.

[0041] In this specification, "opposite" means that surfaces or members are in a position facing each other, including not only the case where they are completely in a facing position but also the case where they are partially in a facing position. Further, in this specification, "opposite" includes both the case where another member is interposed between two parts and the case where nothing is interposed between two parts.

[0042] The first support frame 83 has an annular first frame portion 91 and a cover portion 92 provided on the radially outer side of the first frame portion 91. The first frame portion 91 holds the magnetic flux collecting member 81 such that the inner peripheral surface of the magnetic flux collecting member 81 is exposed on the inner peripheral side of the first support frame 83.

[0043] The second support frame 84 has an annular second frame portion 93 and a support portion 94 provided on the radially outer side of the second frame portion 93. The second frame portion 93 holds the magnetic flux concentrating member 82 such that the inner peripheral surface of the magnetic flux concentrating member 82 is exposed on the inner peripheral side of the second support frame 84. The support portion 94 supports the gear unit 44 and the circuit board 45. The cover portion 92 covers the circuit board 45 supported by the support portion 94 from the rear side.

[0044] (Gear unit 44) In addition to the above-described driven gears 46 and 47, the gear unit 44 includes sensor magnets 101 and 102 that rotate integrally with the driven gears 46 and 47, and a support plate 103. As shown in FIG. 5, the sensor magnet 101 is fixed so as to be rotatable integrally with the driven gear 46. Further, the sensor magnet 102 is fixed so as to be rotatable integrally with the driven gear 47. Note that the peripheral configuration of the driven gear 47 is the same as the peripheral configuration of the driven gear 46. Therefore, the meshing portion between the driven gear 46 and the gear portion 75 is shown in FIG. 5, and the illustration of the meshing portion between the driven gear 47 and the gear portion 75 is omitted.

[0045] The support plate 103 has a flat plate shape. The support plate 103 rotatably supports the driven gears 46 and 47. The support plate 103 is fixed to the second support frame 84 so as to sandwich the driven gears 46 and 47 between the support plate 103 and the support portion 94 of the second support frame 84.

[0046] Each of the driven gears 46 and 47 meshes with the gear portion 75 of the magnetic yoke assembly 42. The driven gears 46 and 47 are arranged on the rear side of the rear end face of the output shaft 14. That is, the driven gears 46 and 47 are arranged in the direction opposite to the direction in which the collar 63 is fitted to the output shaft 14, relative to the rear end of the output shaft 14. The number of teeth of the driven gears 46 and 47 is different from each other. Therefore, when the output shaft 14, that is, the gear portion 75 rotates, the rotation angles of the driven gear 46 and the driven gear 47 are different from each other. In each of the outer teeth of the driven gears 46 and 47, in the rear end region of each outer tooth of the present embodiment, the tooth depth becomes smaller and the tooth thickness becomes thinner as going toward the rear side. In other embodiments, the tooth depth and the tooth thickness of each outer tooth may be constant along the axial direction.

[0047] (Circuit board 45) The circuit board 45 is in a flat plate shape. Various circuit elements including the magnetic sensor 48 and the rotation sensors 49a and 49b are mounted on the circuit board 45. The circuit board 45 is supported by the support portion 94 of the second support frame 84.

[0048] The magnetic sensor 48 is, for example, a Hall sensor or a magnetoresistive sensor. As shown in FIG. 2, the magnetic sensor 48 is mounted in a region sandwiched between the protrusions 85 and 86 on the circuit board 45. The circuit board of other embodiments may be provided with a redundant magnetic sensor different from the magnetic sensor 48, and this magnetic sensor may be mounted in a region sandwiched between another pair of protrusions 85 and 86 on the circuit board 45.

[0049] Here, the sensor magnet 41 rotates integrally with the input shaft 13, and the magnetic yoke assembly 42 rotates integrally with the output shaft 14. When the input shaft 13 and the output shaft 14 rotate relative to each other with torsion of the torsion bar 15 due to a steering operation by the driver, the circumferential relative position between the sensor magnet 41 and the magnetic yoke assembly 42 changes. As a result, the magnetic flux flowing through the magnetic yoke assembly 42 changes according to the amount of torsion of the torsion bar 15, that is, the magnitude of the steering torque input by the driver. Consequently, the magnetic flux flowing through the magnetic flux collecting unit 43 also changes according to the change in the magnetic flux flowing through the magnetic yoke assembly 42. The magnetic sensor 48 detects the magnetic flux flowing through the magnetic flux collecting unit 43 and generates a signal corresponding to this magnetic flux, that is, a signal indicating the steering torque.

[0050] The rotation sensors 49a and 49b are, for example, Hall sensors or magnetoresistive sensors. As shown in FIG. 5, the rotation sensor 49a is mounted in a region facing the sensor magnet 101 on the circuit board 45, and the rotation sensor 49b is mounted in a region facing the sensor magnet 102 on the circuit board 45.

[0051] Here, the driven gears 46 and 47 rotate in response to the rotation of the magnetic yoke assembly 42. Then, the rotation sensors 49a and 49b generate signals indicating the rotation angles of the driven gears 46 and 47, that is, the steering angle. Note that since the rotation angles of the driven gear 46 and the driven gear 47 are different from each other as described above, the phases of the signals generated by the rotation sensors 49a and 49b are different from each other. Therefore, the sensor device 4 of the present embodiment can detect the steering angle at an absolute angle exceeding 360° based on the signals output from the rotation sensors 49a and 49b.

[0052] (Assembly of the sensor device 4) The assembly of the sensor device 4 is performed by sequentially assembling the components of the sensor device 4 from the rear side with respect to the output shaft 14. Among these, the assembly of the magnetic yoke assembly 42 is performed after fixing the gear unit 44 in the housing 23.

[0053] Specifically, the magnetic yoke assembly 42 is assembled from the rear side with respect to the output shaft 14 in a state where the circumferential position with respect to the output shaft 14 of the magnetic yoke assembly 42 is aligned by inserting a part of a jig (not shown) into the alignment groove 79. Thereby, the magnetic yoke assembly 42 is assembled to the output shaft 14, and the magnetic yoke assembly 42 is engaged with the driven gears 46 and 47.

[0054] Next, the operation and effects of the present embodiment will be described. (1) The sensor device 4 includes a sensor magnet 41 that rotates integrally with the input shaft 13 and a magnetic yoke assembly 42 that rotates integrally with the output shaft 14. Further, the sensor device 4 includes a pair of magnetic flux collecting members 81 and 82 that are arranged at intervals on the outer peripheral side of the magnetic yoke assembly 42, and a magnetic sensor 48 that generates a signal according to the magnetic flux flowing through the pair of magnetic flux collecting members 81 and 82. Furthermore, the sensor device 4 includes driven gears 46 and 47 that rotate according to the rotation of the magnetic yoke assembly 42, and rotation sensors 49a and 49b that generate signals according to the rotation angles of the driven gears 46 and 47.

[0055] The magnetic yoke assembly 42 includes a pair of yoke cores 61 and 62, a collar 63, and a holder 64 that holds the pair of yoke cores 61 and 62 and the collar 63. The holder 64 has a gear portion 75 having a plurality of external teeth 77 that project radially outward of the holder 64. The collar 63 is disposed on the inner peripheral side of the gear portion 75. The axial range in which the collar 63 exists in the holder 64 overlaps with the axial range in which the gear portion 75 is provided in the holder 64. Therefore, compared with the case where these axial ranges do not overlap with each other, the axial length of the holder 64 can be shortened, and thus the sensor device 4 can be miniaturized. Thereby, the steering column device 1 can be miniaturized while ensuring the EA stroke.

[0056] (2) The collar 63 has an annular main body portion 71 that fits onto the output shaft 14, and a flange portion 72 that projects radially inward from the inner peripheral surface of the main body portion 71 and abuts against the end of the output shaft 14. Therefore, by the end of the output shaft 14 abutting against the flange portion 72, the axial position of the collar 63 with respect to the output shaft 14, that is, the axial position of the magnetic yoke assembly 42 with respect to the output shaft 14 can be easily adjusted.

[0057] (3) The collar 63 fits onto the output shaft 14 by moving in a first direction along the axis of the holder 64 with respect to the output shaft 14. The tooth grooves 78 between the plurality of external teeth 77 open in the first direction. Therefore, the collar 63 can be fitted onto the output shaft 14 while meshing the gear portion 75 with the driven gears 46, 47. Thereby, the assemblability of the sensor device 4 can be improved.

[0058] (4) The holder 64 further has an alignment portion 76 for aligning the circumferential position of the holder 64 with respect to the output shaft 14. Therefore, the circumferential alignment of the holder 64 with respect to the output shaft 14 becomes easy.

[0059] (5) The collar 63 fits onto the rear end portion of the output shaft 14. The driven gears 46, 47 are arranged in the direction opposite to the first direction with respect to the rear end portion of the output shaft 14. Therefore, during the assembly of the magnetic yoke assembly 42, after at least a part of the gear portion 75 meshes with the driven gears 46, 47, the collar 63 starts to fit onto the outer circumference of the output shaft 14. Therefore, after meshing the gear portion 75 with the driven gears 46, 47 in a state where the circumferential position of the magnetic yoke assembly 42 can be easily changed, the collar 63 can be fitted onto the output shaft 14.

[0060] This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range. ·The driven gears 46 and 47 are arranged on the rear side of the rear end face of the output shaft 14. However, the present invention is not limited to this. The driven gears 46 and 47 may be arranged such that the axial positions of the rear end faces of the driven gears 46 and 47 coincide with the axial position of the rear end face of the output shaft 14. In this case, when assembling the magnetic yoke assembly 42, the gear portion 75 starts to mesh with the driven gears 46 and 47 at the same time that the collar 63 starts to fit onto the output shaft 14. Further, the driven gears 46 and 47 may be arranged on the front side of the rear end face of the output shaft 14. In this case, when assembling the magnetic yoke assembly 42, after at least a part of the collar 63 fits onto the output shaft 14, the gear portion 75 starts to mesh with the driven gears 46 and 47.

[0061] ·The alignment portion 76 is provided so as to protrude axially rearward from the yoke core holding portion 73. However, the present invention is not limited to this. For example, the alignment portion 76 may be provided so as to protrude axially forward from the gear portion 75, or the alignment portion 76 may be provided between the yoke core holding portion 73 and the gear portion 75. Further, instead of the alignment groove 79, the alignment portion 76 may have a structure having, for example, an alignment hole. Furthermore, the holder 64 may not have the alignment portion 76.

[0062] ·The tooth groove 78 of the gear portion 75 does not have to open in the direction of fitting the collar 63 onto the output shaft 14, that is, in the first direction. In this case, for example, the driven gears 46 and 47 are meshed with the gear portion 75 from the radially outer side of the magnetic yoke assembly 42.

[0063] ·The flange portion 72 of the collar 63 is provided at the end portion of the main body portion 71 near the yoke cores 61 and 62. However, the present invention is not limited to this. For example, the flange portion 72 may be provided near the axial center of the main body portion 71. Further, the collar 63 may not have the flange portion 72.

[0064] · Although the entire axial range where the color 63 exists in the holder 64 was included in the axial range where the gear portion 75 was provided in the holder 64, it is not limited to this. A part of the axial range where the color 63 exists in the holder 64 may be outside the axial range where the gear portion 75 was provided in the holder 64.

[0065] · The configuration of the magnetic flux concentrating unit 43 can be appropriately changed as long as it can hold the pair of magnetic flux concentrating members 81 and 82. For example, instead of the first support frame 83 and the second support frame 84, a pair of magnetic flux concentrating members 81 and 82 may be held by a single support frame.

[0066] · The rotation sensors 49a and 49b may be sensors other than the sensors that detect magnetic flux as long as they can detect the rotation angles of the driven gears 46 and 47, such as a rotary encoder. In this case, the sensor magnets 101 and 102 are unnecessary.

[0067] · The gear unit 44 includes two driven gears 46 and 47 that mesh with the gear portion 75, but is not limited to this, and may include only a single driven gear that meshes with the gear portion 75, or three or more driven gears. Further, when the gear unit 44 includes two or more driven gears, each of these driven gears does not necessarily have to mesh with the gear portion 75. For example, one driven gear may mesh with the gear portion 75, and the other driven gears may mesh only with the one driven gear.

[0068] · The sensor magnet 41 was fixed to the input shaft 13, and the magnetic yoke assembly 42 was fixed to the output shaft 14, but the sensor magnet 41 may be fixed to the output shaft 14, and the magnetic yoke assembly 42 may be fixed to the input shaft 13. In this case, the input shaft 13 corresponds to the second shaft, and the output shaft 14 corresponds to the first shaft.

[0069] · The sensor device 4 was provided on the outer periphery of the column shaft 2, but is not limited to this, and may be provided on the outer periphery of, for example, a pinion shaft that constitutes a rack and pinion mechanism.

Claims

1. A pair of yoke cores, A circular collar and a cylindrical holder for holding the pair of yoke cores and the collar, the holder has a gear portion having a plurality of external teeth protruding radially outward from the holder, The collar is disposed on an inner peripheral side of the gear portion, A magnetic yoke assembly, wherein an axial range of the holder in which the collar is present overlaps with an axial range of the holder in which the gear portion is provided.

2. 2. The magnetic yoke assembly of claim 1, The color is An annular main body portion that fits onto the shaft; a flange portion protruding radially inward from an inner circumferential surface of the main body portion and configured to abut against an end of the shaft.

3. 3. The magnetic yoke assembly according to claim 2, the collar is configured to move relative to the shaft in a first direction along an axis of the holder to engage with the shaft; A magnetic yoke assembly, wherein tooth spaces between the plurality of external teeth are open in the first direction.

4. A magnetic yoke assembly according to any one of claims 1 to 3, The holder further includes an alignment portion configured to circumferentially align the holder relative to a shaft on which the collar is fitted.

5. A sensor magnet configured to rotate integrally with the first shaft; The magnetic yoke assembly according to any one of claims 1 to 4, which is configured to rotate integrally with a second shaft connected to the first shaft via a torsion bar; a pair of magnetic flux collectors arranged at an outer periphery of the magnetic yoke assembly with a gap therebetween; a magnetic sensor that generates a signal according to the magnetic flux flowing through the pair of magnetic flux collecting members; a driven gear that rotates in response to rotation of the magnetic yoke assembly; a rotation sensor that generates a signal according to a rotation angle of the driven gear.

6. The sensor device according to claim 5, the collar of the magnetic yoke assembly is configured to move relative to an end of the second shaft in a first direction along an axis of the holder to engage with the end; The driven gear is disposed in a direction opposite to the first direction relative to the end portion.

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