Steering angle sensor

Abstract

A steering angle sensor 10 comprises: a main gear 11 that is attached to a steering shaft 82 and that rotates integrally with the steering shaft 82; a driven gear assembly 40 that has two driven gears 15 which mesh with the main gear 11 and a sensor 18 which detects rotation of the driven gears 15; and a housing 20 that covers a part of the steering shaft 82 where the main gear 11 is disposed, wherein the housing 20 has an accommodation part 26 that accommodates the driven gear assembly 40, the driven gear assembly 40 has a protruding part 45 that is accommodated inside the accommodation part 26, the two driven gears 15 are disposed alongside each other inward of the protruding part 45, and the protruding part 45 has, on side walls 46a of an outer peripheral surface 46 of the protruding part 45 on both sides in the direction in which the two driven gears 15 are arranged, a plurality of crush ribs 47 that abut on an accommodation part inner wall 27, which is an inner wall of the accommodation part 26.

Description

Steering angle sensor

[0001] This disclosure relates to a steering angle sensor.

[0002] Steering angle sensors capable of detecting the steering angle of a steering wheel are known. For example, in the steering angle sensor described in Patent Document 1, it has a main gear attached to a shaft, a driven gear that rotates passively as the main gear rotates, and a magnetic sensor that detects the rotation of the driven gear. Two driven gears that rotate passively as the main gear rotates are provided for the driven gear.

[0003] Japanese Patent Application Laid-Open No. 2024-51979

[0004] Here, in the case of a steering angle sensor provided with two driven gears meshing with the main gear and detecting the steering angle using the two driven gears, it is necessary to appropriately mesh the two driven gears with the main gear respectively. However, when assembling the steering angle sensor, if the relative position of the driven gear with respect to the main gear is shifted from the position at the time of design and assembled, the driven gear may not mesh properly with the main gear.

[0005] For example, when the relative position of the driven gear with respect to the main gear is shifted from the position at the time of design and assembled, it is conceivable that only one of the two driven gears meshes with the main gear and the other driven gear is assembled in a state where it does not mesh with the main gear. When detecting the steering angle by meshing two driven gears with the main gear attached to the shaft and detecting the rotation of the two driven gears that rotate as the main gear rotates, if one of the two driven gears does not mesh with the main gear, it becomes difficult to appropriately detect the steering angle.

[0006] Thus, when the driven gear is assembled at a position shifted from the main gear in the steering angle sensor, it becomes difficult to appropriately detect the steering angle. Therefore, there was room for improvement from the viewpoint of suppressing the difficulty in detecting the steering angle and ensuring a state where the steering angle can be appropriately detected.

[0007] This disclosure has been made in view of the above, and aims to provide a steering angle sensor that can suppress the difficulty in appropriately detecting the steering angle.

[0008] The steering angle sensor of the present disclosure comprises a driven gear assembly having an annular main gear mounted on a shaft that rotates with a steering wheel and rotates integrally with the shaft, two driven gears that mesh with the main gear, and a sensor for detecting the rotation of the driven gears, and a housing that covers the portion of the shaft on which the main gear is located, wherein the housing has a storage portion for storing the driven gear assembly, the driven gear assembly has a protruding portion that is stored inside the storage portion, the two driven gears are arranged side by side inside the protruding portion with their respective axis of rotation parallel to each other, and the protruding portion has a plurality of crush ribs on both sides of the outer circumferential surface of the protruding portion in the direction in which the two driven gears are aligned, which abut against the inner wall of the storage portion.

[0009] In this configuration, the driven gear assembly, which has two driven gears that mesh with the main gear, has multiple crush ribs that contact the inner wall of the storage compartment on both sides of the outer circumferential surface of the protruding part that is stored in the storage compartment, in the direction in which the two driven gears are aligned. As a result, the driven gear assembly can store the protruding part in the storage compartment without the angle of the protruding part tilting from the appropriate angle when viewed in the axial direction of the shaft. This allows the two driven gears of the driven gear assembly to mesh with the main gear in the appropriate position and orientation, and prevents the driven gears from failing to mesh with the main gear due to the tilt of the protruding part. Consequently, both of the two driven gears of the driven gear assembly can be properly meshed with the main gear, and the steering angle can be accurately detected using the two driven gears that mesh with the main gear. As a result, it is possible to prevent difficulties in properly detecting the steering angle.

[0010] In a preferred configuration, the crush rib abuts the inner wall of the storage compartment with a length shorter than the length of the protrusion in the direction of insertion of the protrusion into the storage compartment.

[0011] With this configuration, the crush rib contacts the inner wall of the storage compartment with a length shorter than the length of the protrusion in the insertion direction of the protrusion into the storage compartment. Therefore, when inserting the protrusion into the storage compartment while deforming the crush rib, insertion can be performed with less force compared to when the contact length of the crush rib with the inner wall of the storage compartment is longer. This makes it easier to assemble the steering angle sensor by inserting the protrusion of the driven gear assembly into the storage compartment of the housing, improving the ease of assembly of the steering angle sensor. As a result, the manufacturing cost of the steering angle sensor can be reduced.

[0012] In a desirable configuration, the crush rib has a length in the insertion direction that is shorter than the length of the protruding portion in the insertion direction.

[0013] With this configuration, the length of the crush rib in the direction of insertion of the protrusion into the housing is shorter than the length of the protrusion in the same direction. Therefore, the contact length of the crush rib with the inner wall of the housing can be made shorter than the length of the protrusion. This allows the protrusion to be inserted into the housing with less force while deforming the crush rib, improving the ease of assembly of the steering angle sensor. As a result, the manufacturing cost of the steering angle sensor can be reduced.

[0014] In a preferred configuration, the crush rib extends along the insertion direction of the protrusion into the storage portion and has a tapered portion in which the height from the outer surface of the protrusion decreases as it approaches the tip of the protrusion in the insertion direction.

[0015] With this configuration, the crush rib has a tapered portion that decreases in height from the outer surface of the protrusion towards the tip of the protrusion. Therefore, when inserting the protrusion into the housing, the crush rib can be pressed into the housing while being guided by the tapered portion. This improves the ease of assembling the driven gear assembly to the housing when a crush rib is provided on the protrusion to properly mesh the driven gear with the main gear. As a result, the ease of assembling the steering angle sensor can be improved.

[0016] In a preferred configuration, the driven gear assembly includes a seal member placement portion where a seal member is arranged, the housing has a seal member contact portion on the inlet side of the storage portion in the insertion direction of the protrusion into the storage portion, the seal member contacts the inner circumferential surface of the seal member, the seal member is arranged in the seal member placement portion and contacts both the seal member placement portion and the seal member contact portion at a position on the inlet side of the storage portion in the insertion direction.

[0017] With this configuration, when inserting the protruding part into the storage section, a seal between the sensor housing and the housing can be ensured at a position closer to the entrance of the storage section than the storage section in the insertion direction. Therefore, water entering the storage section from the entrance side of the storage section can be suppressed. Consequently, water entering the inside of the housing can be suppressed, and the reduction in steering angle detection accuracy due to water adhering to the steering angle sensor can be suppressed. As a result, the steering angle can be detected with high accuracy over a long period of time.

[0018] In a preferred configuration, the inner wall of the storage section has a tapered portion where the distance between the inner wall of the storage section and the outer surface of the protrusion decreases as you move from the opening side of the storage section toward the rear in the direction of insertion of the protrusion into the storage section, and a flat portion located further rear than the tapered portion in the insertion direction where the distance between the inner wall of the storage section and the outer surface of the protrusion remains constant, and the crush rib abuts against the inner wall of the storage section at the flat portion.

[0019] With this configuration, the contact length of the crush rib against the inner wall of the storage section can be made shorter than the length of the protrusion of the sensor housing. Therefore, when inserting the protrusion into the storage section while deforming the crush rib, insertion requires less force. In addition, since the inner wall of the storage section has a tapered section on the entrance side of the storage section rather than the flat section, it is possible to easily insert the protrusion of the driven gear assembly into the housing storage section. In other words, when inserting the protrusion into the storage section, the crush rib, which is positioned on the outer circumference of the protrusion, can be guided by the tapered section and pressed into the flat section. This improves the ease of assembling the driven gear assembly to the housing when a crush rib is provided on the protrusion to position the driven gear assembly relative to the housing. As a result, the ease of assembly of the steering angle sensor can be improved, and the manufacturing cost of the steering angle sensor can be reduced.

[0020] In a preferred configuration, the inner wall of the storage section has an enlarged diameter portion located on the opening side of the storage section in the direction of insertion of the protrusion into the storage section, and spaced away from the outer circumferential surface of the protrusion, and a reduced diameter portion located further back than the enlarged diameter portion in the insertion direction, and the distance from the outer circumferential surface of the protrusion is smaller than the distance between the enlarged diameter portion and the outer circumferential surface of the protrusion, and the crush rib abuts against the inner wall of the storage section at the reduced diameter portion.

[0021] In this configuration, the inner wall of the housing's storage section has an enlarged diameter section and a reduced diameter section, and the crush rib, which is arranged on the outer circumferential surface of the protruding portion, contacts the inner wall of the housing section at the reduced diameter section. As a result, the crush rib can contact the inner wall of the housing section at a position away from the seal member arrangement section. Therefore, even if the protruding portion 45 deforms due to the crush rib contacting the inner wall 27 of the housing section, the deformation of the protruding portion is less likely to affect the seal member arrangement section, and the deformation of the seal member arrangement section accompanying the deformation of the protruding portion can be suppressed. This makes it possible to appropriately crush the seal member arranged in the seal member arrangement section of the driven gear assembly. As a result, the sealing performance of the seal member can be improved.

[0022] In a preferred configuration, the shaft has a first shaft, a second shaft, and a torsion bar connecting the first shaft and the second shaft, and includes a torque sensor having a stator attached to one of the first shaft and the second shaft, and a magnet attached to the other of the first shaft and the second shaft and positioned inside the stator in the radial direction of the shaft, and the main gear is attached to the stator and attached to the shaft via the stator.

[0023] With this configuration, the main gear is attached to the stator of the torque sensor, which is mounted on the shaft. This allows for the simultaneous assembly of the steering angle sensor and the torque sensor, simplifying the manufacturing process. As a result, manufacturing costs can be reduced. Furthermore, by attaching the main gear to the stator of the torque sensor, the steering angle sensor and the torque sensor can be integrated, allowing for miniaturization of both sensors. Consequently, the steering system, which includes both a steering angle sensor and a torque sensor, can be miniaturized.

[0024] In a preferred configuration, the stator has an annular flange portion, the driven gear assembly has a magnetizing yoke for the torque sensor arranged on top of the flange portion of the stator at a distance from it, and the protrusion has a plurality of crush ribs on both sides of the outer circumferential surface of the protrusion in the axial direction of the shaft that abut against the inner wall of the housing.

[0025] With this configuration, the projection of the driven gear assembly has multiple crush ribs on both sides of its outer circumferential surface in the axial direction of the shaft, allowing the projection to be inserted into the housing's storage portion in an appropriate position and orientation in the axial direction of the shaft. This allows the magnetic collecting yoke, which is placed in the driven gear assembly, to be positioned at an appropriate distance from the stator flange in the axial direction of the shaft. Consequently, the detection accuracy when detecting changes in magnetic flux from the stator with the magnetic collecting yoke can be improved. As a result, the detection accuracy of steering torque by the torque sensor can be improved.

[0026] The steering angle sensor described herein has the effect of suppressing the difficulty in properly detecting the steering angle.

[0027] Figure 1 is a schematic diagram illustrating a steering device according to the first embodiment. Figure 2 is a schematic diagram of the steering angle sensor and torque sensor area in the steering device. Figure 3 is a side view of the steering angle sensor shown in Figure 2. Figure 4 is a plan view of the driven gear assembly as seen in the direction of the A-A arrow in Figure 3. Figure 5 is a perspective view of the main gear shown in Figure 3. Figure 6 is a cross-sectional view of the driven gear assembly shown in Figure 3. Figure 7 is a cross-sectional view of the housing shown in Figure 6. Figure 8 is a view as seen along the B-B arrow in Figure 6. Figure 9 is a schematic diagram illustrating the outline of the magnet, stator, and magnetic collection yoke of the torque sensor. Figure 10 is an explanatory diagram of the assembly of the driven gear assembly in a configuration in which crush ribs are not provided on the sensor housing of the driven gear assembly. Figure 11 is an explanatory diagram of the assembly of the driven gear assembly in the steering angle sensor according to the first embodiment. Figure 12 is an explanatory diagram showing the state in which the driven gear of the driven gear assembly shown in Figure 11 meshes with the main gear. Figure 13 is a side view of the steering angle sensor according to the second embodiment. Figure 14 is a perspective view of the driven gear assembly and stator in the steering angle sensor according to the second embodiment. Figure 15 is a view taken along the line C-C in Figure 13. Figure 16 is a plan view of the driven gear assembly in the steering angle sensor according to the third embodiment. Figure 17 is a schematic diagram showing the state in which the protruding portion of the driven gear assembly shown in Figure 16 is stored in the housing. Figure 18 is a cross-sectional view of the housing of the steering angle sensor according to the fourth embodiment. Figure 19 is a schematic diagram showing the state in which the protruding portion of the driven gear assembly is stored in the housing in the fourth embodiment. Figure 20 is a modified example of the steering angle sensor according to the fourth embodiment, and is a schematic diagram showing a form in which the inner wall of the housing has an enlarged diameter portion and a reduced diameter portion.

[0028] The present disclosure will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the embodiments described below. Furthermore, the components in the embodiments below include those easily conceivable by those skilled in the art, those substantially identical, and those within the scope of equivalents. Moreover, the components disclosed in the embodiments below can be combined as appropriate.

[0029] [First Embodiment] Figure 1 is a schematic diagram illustrating a steering device 80 according to the first embodiment. As shown in Figure 1, the steering device 80 according to the first embodiment includes, in the order in which the force applied by the operator is transmitted, a steering wheel 81, a steering shaft 82, a steering angle sensor 10, a torque sensor 50, an electric motor 101, a reduction gear 102, a universal joint 91, an intermediate shaft 92, and a universal joint 93, all connected to a pinion shaft 94.

[0030] The steering wheel 81 is connected to one end of the steering shaft 82. The steering shaft 82 is a shaft that rotates together with the steering wheel 81 and comprises a first axis, which is an input shaft 83, a second axis, which is an output shaft 86, and a torsion bar 90 (see Figure 2) that connects the input shaft 83 and the output shaft 86. The steering angle sensor 10 detects the steering angle of the steering shaft 82 that rotates together with the steering wheel 81. The torque sensor 50 detects the torque transmitted between the input shaft 83 and the output shaft 86. The steering angle sensor 10 and the torque sensor 50 will be described in detail later.

[0031] The intermediate shaft 92 connects the universal joint 91 and the universal joint 93. One end of the intermediate shaft 92 is connected to the universal joint 91, and the other end is connected to the universal joint 93. One end of the pinion shaft 94 is connected to the universal joint 93, and the other end is connected to the steering gear 95. The universal joints 91 and 93 are, for example, cardan joints. The rotation of the steering shaft 82 is transmitted to the pinion shaft 94 via the intermediate shaft 92. Therefore, the intermediate shaft 92 is rotatable together with the steering shaft 82 and rotates together with the steering wheel 81, just like the steering shaft 82.

[0032] The steering gear 95 comprises a pinion gear 95a and a rack bar 95b. The pinion gear 95a is connected to the pinion shaft 94. The rack bar 95b meshes with the pinion gear 95a. The steering gear 95 converts the rotational motion transmitted to the pinion gear 95a into linear motion using the rack bar 95b. The rack bar 95b is connected to the tie rod 96. The movement of the rack bar 95b changes the angle of the wheels. In other words, the steering device 80 is a rack and pinion type electric power steering device.

[0033] The steering system 80 further includes an ECU (Electronic Control Unit) 100 and a vehicle speed sensor 105. The electric motor 101, vehicle speed sensor 105, steering angle sensor 10, and torque sensor 50 are electrically connected to the ECU 100. The reduction gear 102 is attached to the electric motor 101 and transmits the power generated by the electric motor 101 as auxiliary steering torque to the steering shaft 82. The steering angle sensor 10 outputs the steering angle of the steering shaft 82, which rotates together with the steering wheel 81, to the ECU 100 via CAN (Controller Area Network) communication. The torque sensor 50 outputs the steering torque transmitted to the steering shaft 82 to the ECU 100 via CAN communication. The vehicle speed sensor 105 detects the driving speed (vehicle speed) of the vehicle on which the steering system 80 is mounted. The vehicle speed sensor 105 is mounted on the vehicle body and outputs the vehicle speed to the ECU 100 via CAN communication.

[0034] The ECU 100 controls the operation of the electric motor 101. The ECU 100 acquires signals from the steering angle sensor 10, the torque sensor 50, and the vehicle speed sensor 105. The ECU 100 is supplied with power from the power supply unit 109 (for example, the vehicle's battery) when the ignition switch 108 is ON. The ECU 100 calculates an auxiliary steering command value based on the steering angle, steering torque, and vehicle speed. The ECU 100 adjusts the power value supplied to the electric motor 101 based on the auxiliary steering command value. The ECU 100 acquires information on the induced voltage of the electric motor 101 or information output from a resolver or the like provided on the electric motor 101. By controlling the electric motor 101, the ECU 100 controls the auxiliary steering torque applied to the steering shaft 82, reducing the force required to operate the steering wheel 81.

[0035] Figure 2 is a schematic diagram of the steering angle sensor 10 and torque sensor 50 in the steering device 80. The steering shaft 82 has an input shaft 83, an output shaft 86, and a torsion bar 90, which are arranged so that their central axes coincide. The steering wheel 81 connected to the steering shaft 82 is connected to the end of the input shaft 83 on the side where the output shaft 86 is located.

[0036] The torsion bar 90 is connected to both the input shaft 83 and the output shaft 86. More specifically, the diameter of the torsion bar 90 is smaller than the diameters of the input shaft 83 and the output shaft 86, and holes (not shown) are formed in the radially inward direction of the input shaft 83 and the output shaft 86 into which the torsion bar 90 is inserted. One end of the torsion bar 90 is inserted into the hole formed in the input shaft 83 and connected to the input shaft 83, and the other end is inserted into the hole formed in the output shaft 86 and connected to the output shaft 86. In this way, the torsion bar 90 is connected to both the input shaft 83 and the output shaft 86. In other words, the input shaft 83 and the output shaft 86 of the steering shaft 82 are connected to each other via the torsion bar 90.

[0037] The steering angle sensor 10 of the steering device 80 comprises a main gear 11, a driven gear 15, a magnet 16, and a sensor 18. The main gear 11 is an annular gear attached to the steering shaft 82 and rotating integrally with the steering shaft 82, with gears mounted on the outer circumference of the annule. In the first embodiment, the main gear 11 is attached to the input shaft 83 of the steering shaft 82. The main gear 11 is attached to the outer surface of the steering shaft 82 in a orientation in which the central axis of the annule coincides with the central axis of the steering shaft 82. In the first embodiment, the main gear 11 is attached to the input shaft 83 of the steering shaft 82.

[0038] The driven gear 15 is a gear that meshes with the gear on the outer circumference of the main gear 11, and the gear that meshes with the gear on the main gear 11 is located on the outer circumference of the driven gear 15. The driven gear 15 is positioned so that its axis of rotation is parallel to the axis of rotation of the steering shaft 82 and the main gear 11. Because the driven gear 15 meshes with the main gear 11, it is able to rotate by transmitting the rotation of the main gear 11, which rotates together with the steering shaft 82. The steering angle sensor 10 has two driven gears 15 (see Figure 4), and each of the two driven gears 15 meshes with the main gear 11, and is able to rotate by transmitting the rotation of the main gear 11.

[0039] The magnet 16 is positioned on the driven gear 15 and rotates together with the driven gear 15 when the driven gear 15 rotates. The magnet 16 is positioned on each of the two driven gears 15 of the steering angle sensor 10, and the magnet 16 positioned on each driven gear 15 is positioned inside the gear of the driven gear 15 in the radial direction of the driven gear 15. The magnet 16 has alternating south poles and north poles magnetized on its outer surface. Therefore, when the magnet 16 rotates, the magnet 16 that rotates together with the driven gear 15 rotates with the south pole and north pole of the magnet 16 around the rotation axis of the driven gear 15, that is, the magnetic field of the magnet 16 rotates in conjunction with the rotation of the driven gear 15.

[0040] Sensor 18 detects the rotation of the driven gear 15. Sensor 18 is, for example, a Hall-type magnetic sensor having a Hall element, and includes a Hall element (not shown) that detects changes in the magnetic flux of a magnet 16 placed on the driven gear 15, and an output circuit (not shown) that converts the output voltage output from the Hall element in response to the change in magnetic flux into a digital electrical signal. Note that instead of a Hall-type magnetic sensor, a magnetic sensor that utilizes the magnetoresistance effect or the tunnel magnetoresistance effect may be used for sensor 18.

[0041] Sensor 18 detects the rotation of the driven gear 15 by detecting the magnetic flux of a magnet 16 placed on the driven gear 15 and detecting the movement of the magnetic field. In other words, sensor 18 detects the rotation of the driven gear 15 by detecting the change in the magnetic field of the magnet 16, which rotates integrally with the driven gear 15, in the circumferential direction around the rotation axis of the driven gear 15. The steering angle sensor 10 has two sensors 18 corresponding to the two driven gears 15 that the steering angle sensor 10 has, and the two sensors 18 are each capable of detecting the rotation of the corresponding driven gear 15. Sensor 18 is able to detect the movement of the main gear 11 in the circumferential direction around the rotation axis of the steering shaft 82 by detecting the rotation of the driven gear 15, and thereby detect the steering angle of the steering shaft 82.

[0042] The driven gear 15 and the sensor 18 are arranged within a sensor housing 41 that covers them. The sensor housing 41 rotatably supports the driven gear 15, and the sensor 18 is positioned within the sensor housing 41 so as to be able to detect the rotation of the driven gear 15 by detecting the magnetic field of a magnet 16 placed on the driven gear 15. For this reason, the sensor 18 is positioned near the driven gear 15 within the sensor housing 41, specifically, near the driven gear 15 in the axial direction of the rotation axis of the driven gear 15. The sensor 18 is positioned near the driven gear 15 within the sensor housing 41 by, for example, mounting it on a printed circuit board (not shown) located within the sensor housing 41.

[0043] Also, the two driven gears 15 and the two sensors 18 of the steering angle sensor 10 are arranged within one sensor housing 41. In this way, the sensor housing 41, the two driven gears 15 rotatably arranged within the sensor housing 41, and the two sensors 18 for detecting the rotation of the two driven gears 15 constitute the driven gear assembly 40. That is, the driven gear assembly 40 has the two driven gears 15 and the two sensors 18.

[0044] FIG. 3 is a side view of the steering angle sensor 10 shown in FIG. 2. FIG. 4 is a plan view of the driven gear assembly 40 viewed in the direction of the arrow A - A in FIG. 3. In the following description, when there is no specific description regarding the direction, the axial direction Z of the steering shaft 82 on which the steering angle sensor 10 is arranged will also be described as the axial direction Z in the steering angle sensor 10. Similarly, the circumferential direction centered on the axis of the steering shaft 82 will also be described as the circumferential direction in the steering angle sensor 10, and the radial direction centered on the axis of the steering shaft 82 will also be described as the radial direction in the steering angle sensor 10. Further, among the radial directions of the steering angle sensor 10, the direction along the radial direction (the left - right direction of the paper surface in FIG. 3) at the position where the driven gear assembly 40 is arranged in the circumferential direction will be described as the length direction Y of the steering angle sensor 10 or the length direction Y of the driven gear assembly 40. Also, the direction orthogonal to both the length direction Y and the axial direction Z (the depth direction of the paper surface in FIG. 3) will be described as the width direction X of the steering angle sensor 10 or the width direction X of the driven gear assembly 40. In the first embodiment, the length direction Y is a direction orthogonal to the axial direction Z in a cross - section passing through the axis of the steering shaft 82 and the center of the driven gear assembly 40 in the width direction X.

[0045] The two driven gears 15 of the driven gear assembly 40 are held by the sensor housing 41 at the same position in the axial direction Z and at different positions in the width direction X. The two driven gears 15 are arranged side by side in the width direction X inside the sensor housing 41 in such a direction that the rotation axes of the respective driven gears 15 are parallel to each other. Since the driven gears 15 are arranged to mesh with the main gear 11, a part thereof is located inside the sensor housing 41, another part is exposed outside the sensor housing 41, and it meshes with the main gear 11 outside the sensor housing 41.

[0046] The two driven gears 15 arranged side by side in the width direction X in the driven gear assembly 40 mesh with the main gear 11 at different positions in the circumferential direction with respect to the main gear 11 attached to the steering shaft 82.

[0047] The two driven gears 15 and the sensor 18 (see FIG. 2) of the driven gear assembly 40 all detect the rotation of the steering shaft 82 by rotating as the main gear 11 rotates, but the two driven gears 15 and the sensor 18 have different objects of detected rotation. That is, the two sets of driven gears 15 and sensors 18 have different rotation objects to be detected when detecting the rotation of the steering shaft 82.

[0048] Among the two sets of driven gears 15 and sensors 18, one driven gear 15 and sensor 18 detect the rotational position of the steering shaft 82 in the circumferential direction. For example, when an arbitrary rotational position of the steering shaft 82 is set as 0°, it detects what degree the current rotational position of the steering shaft 82 is.

[0049] On the other hand, the other driven gear 15 and sensor 18 detect the rotational speed of the steering shaft 82. That is, it detects how many rotations the current rotation of the steering shaft 82 is with respect to an arbitrary reference rotational state when one rotation is defined as a 360° rotation of the steering shaft 82 in the circumferential direction.

[0050] The steering angle sensor 10 can detect the steering angle of the steering shaft 82 by detecting the rotational position and rotational speed of the steering shaft 82 using two sets of driven gears 15 and sensors 18 as described above.

[0051] Figure 5 is a perspective view of the main gear 11 shown in Figure 3. The main gear 11, with which the driven gear 15 of the driven gear assembly 40 meshes, has a body portion 11a, a mounting portion 11b, and a support member 11c. In the first embodiment, the main gear 11 is made of a resin material. The body portion 11a of the main gear 11 is formed in a substantially cylindrical shape with an inner diameter larger than the outer diameter of the steering shaft 82, and a gear with which the driven gear 15 meshes is formed on the outer circumferential surface of the cylinder.

[0052] The mounting portion 11b is formed in a substantially cylindrical shape with an inner diameter approximately the same as the outer diameter of the steering shaft 82, and is designed to fit onto the steering shaft 82. The support member 11c is positioned between the main body portion 11a and the mounting portion 11b and serves as a connecting member between the main body portion 11a and the mounting portion 11b.

[0053] In other words, the mounting portion 11b of the main gear 11 is located at a different position in the axial direction from the main body portion 11a, and the support member 11c is positioned between the main body portion 11a and the mounting portion 11b, which are offset from each other in the axial direction, connecting the main body portion 11a and the mounting portion 11b. As a result, the main gear 11 is formed integrally with the main body portion 11a, the mounting portion 11b, and the support member 11c.

[0054] The main gear 11, formed in this manner, has its mounting portion 11b fitted onto the steering shaft 82 by press-fitting. This allows the main gear 11 to be mounted at a desired position on the steering shaft 82. The driven gear assembly 40 is positioned in the axial direction Z such that the driven gear 15 can mesh with the main gear 11 mounted on the steering shaft 82.

[0055] Figure 6 is a cross-sectional view of the driven gear assembly 40 shown in Figure 3. Figure 7 is a cross-sectional view of the housing 20 shown in Figure 6. The driven gear assembly 40 of the steering angle sensor 10 is located inside the housing 20, which covers the portion of the steering shaft 82 where the main gear 11 is located, and is detachably attached to the housing 20. More specifically, the housing 20 has a storage section 26 for storing the driven gear assembly 40, and the storage section 26 is formed in a hole-like shape that opens radially outward from the inner circumferential surface 21 of the housing 20. The driven gear assembly 40 is located inside the storage section 26 by a part of the outer circumferential surface of the driven gear assembly 40 contacting the inner wall 27 of the storage section, which is the inner wall of the storage section 26.

[0056] The driven gear assembly 40 is inserted radially into the housing 26 from the radially outer side toward the inner circumferential surface 21. In other words, the driven gear assembly 40 is inserted into the housing 26 from the radially outer side toward the inner side toward the housing 20 in the longitudinal direction Y. In the following description, the direction in which the driven gear assembly 40 is inserted into the housing 26 will also be referred to as the insertion direction.

[0057] The driven gear assembly 40 is inserted into the housing 20's storage section 26 with the side where the driven gear 15 is located in the longitudinal direction Y facing inward in the radial direction. By inserting the driven gear assembly 40 into the housing 20's storage section 26 with the side where the driven gear 15 is located facing inward in the radial direction, the driven gear 15 is exposed to the inside of the housing 20. As a result, the driven gear 15 of the driven gear assembly 40 meshes with the main gear 11 attached to the steering shaft 82 on the inside of the housing 20.

[0058] The sensor housing 41 (see Figures 3 and 4) of the driven gear assembly 40 is made of resin material and has a flange portion 42, a connector portion 43, and a protruding portion 45. The flange portion 42 is a plate-shaped part through which the sensor housing 41 is attached to the housing 20. The flange portion 42 has bolt holes (not shown) through which mounting bolts (not shown) that attach the driven gear assembly 40 to the housing 20 pass. The sensor housing 41 is attached to the housing 20 by attaching the flange portion 42 to the radial outer end face of the portion of the housing 20 in which the storage portion 26 is formed, using mounting bolts.

[0059] The connector portion 43 is positioned radially outward relative to the flange portion 42 when the driven gear assembly 40 is mounted on the housing 20. The terminals extending from the sensor 18 of the driven gear assembly 40 are positioned on the inside of the connector portion 43, and it is the part that connects the terminals extending from the sensor 18 to the external terminals. The driven gear assembly 40 can electrically connect the steering angle sensor 10 and the ECU 100 by connecting the terminals extending from the sensor 18 to the external terminals at the connector portion 43.

[0060] The protruding portion 45 is positioned radially inward relative to the flange portion 42 when the driven gear assembly 40 is attached to the housing 20. Therefore, the protruding portion 45 is the part of the driven gear assembly 40 that is inserted into and stored in the storage portion 26 of the housing 20. In the length direction Y, the protruding portion 45 is positioned on the opposite side of the flange portion 42 from the side where the connector portion 43 is located, and protrudes toward the opposite side of the side where the connector portion 43 is located. In other words, the sensor housing 41 has the connector portion 43 positioned on one side in the thickness direction of the plate-shaped flange portion 42, and the protruding portion 45 positioned on the other side. Both the connector portion 43 and the protruding portion 45 are smaller in size in the width direction X than the flange portion 42, and their size in the axial direction Z is also smaller than that of the flange portion 42.

[0061] A space is formed inside the protrusion 45, and the sensor 18 of the driven gear assembly 40 is positioned inside the protrusion 45 in the sensor housing 41, while a portion of the driven gear 15 is positioned inside the protrusion 45 and rotatably held in the sensor housing 41. That is, the two driven gears 15 of the driven gear assembly 40 are positioned side by side inside the protrusion 45 with their respective axis of rotation parallel to each other, and are rotatably held in the sensor housing 41.

[0062] The protruding portion 45 is formed such that the shape of the end 45a opposite to the side where the flange portion 42 is located in the longitudinal direction Y is curved, and when the sensor housing 41 is viewed in the axial direction Z, it is recessed towards the side where the flange portion 42 is located in the longitudinal direction Y. The curved shape of the end 45a of the protruding portion 45 is such that, when the driven gear assembly 40 is attached to the housing 20, the center of the arc substantially coincides with the axis of the steering shaft 82 (see Figure 3).

[0063] Furthermore, the protruding portion 45 has a plurality of crush ribs 47 on its outer peripheral surface 46. The crush ribs 47 are formed to protrude from the outer peripheral surface 46 of the protruding portion 45 and are rib-shaped members that are lightly press-fitted against the inner wall 27 of the storage portion 27 by contacting it when the protruding portion 45 is inserted into the storage portion 26 of the housing 20. Unlike ordinary ribs used to reinforce members, the crush ribs 47 are arranged to ensure the relative positional accuracy of the protruding portion 45 with respect to the storage portion 26 when inserted into the storage portion 26 of the housing 20 by contacting the inner wall 27 and being lightly press-fitted against it. The crush ribs 47 protrude from the outer peripheral surface 46 of the protruding portion 45 and are formed in a rib-shaped form that extends in the longitudinal direction Y. That is, the crush ribs 47 are formed to extend along the direction in which the protruding portion 45 is inserted into the storage portion 26. The crushed rib 47 is formed at a relatively low height from the outer peripheral surface 46 of the protruding portion 45, and is also formed with a relatively narrow width.

[0064] The multiple crush ribs 47 of the protruding portion 45 are arranged on both sides 46a of the outer circumferential surface 46 of the protruding portion 45 in the direction in which the two driven gears 15 are aligned, that is, on both sides 46a of the protruding portion 45 in the width direction X. In addition, the multiple crush ribs 47 of the protruding portion 45 are also arranged on both sides 46b of the outer circumferential surface 46 of the protruding portion 45 in the axial direction Z of the steering shaft 82.

[0065] The length of the crush rib 47 in the longitudinal direction Y is the same as the length of the protruding portion 45 in the portion where the crush rib 47 is located. Here, the protruding portion 45 has a curved shape when viewed in the axial direction Z at the end 45a opposite to the side where the flange portion 42 is located in the longitudinal direction Y. Therefore, in the portion of the protruding portion 45 where the end 45a is curved when viewed in the axial direction Z, the length in the longitudinal direction Y is shorter than the length of the portion of the protruding portion 45 other than the portion where the end 45a is curved.

[0066] Of the multiple crush ribs 47 arranged on the outer circumferential surface 46 of the protruding portion 45, the crush ribs 47 arranged on both sides of the side 46b in the axial direction Z are located in the same position in the width direction X as the portion where the end 45a of the protruding portion 45 in the length direction Y is curved. Therefore, of the multiple crush ribs 47 arranged on the outer circumferential surface 46 of the protruding portion 45, the crush ribs 47 arranged on both sides of the side 46b in the axial direction Z have a shorter length in the length direction Y than the crush ribs 47 arranged on both sides of the side 46a in the width direction X.

[0067] The crush ribs 47 formed in this manner have a tapered portion 47a in which the height from the outer peripheral surface 46 of the protrusion 45 decreases as it approaches the tip side of the protrusion 45 in the insertion direction, that is, as it approaches the end 45a side in the longitudinal direction Y of the protrusion 45. In other words, the end of the crush rib 47 opposite to the side where the flange portion 42 is located in the longitudinal direction Y is formed in a chamfered shape, thereby forming a tapered portion 47a.

[0068] When attaching the driven gear assembly 40 to the housing 20, the projection 45 of the sensor housing 41 of the driven gear assembly 40 is inserted into the housing 26 in a direction that protrudes from the flange portion 42 toward the side where the housing portion 26 of the housing 20 is located in the longitudinal direction Y (see Figure 6).

[0069] The driven gear assembly 40 is installed by inserting the protruding portion 45 of the sensor housing 41 into the storage portion 26 and storing it inside the storage portion 26, and then attaching the flange portion 42 of the sensor housing 41 to the housing 20 with mounting bolts (not shown). As a result, the driven gear assembly 40 is installed in the housing 20 with the protruding portion 45 of the sensor housing 41 stored in the storage portion 26 of the housing 20, and the driven gear 15, which is positioned inside the protruding portion 45, positioned in the desired location.

[0070] Figure 8 is a view along the line B-B in Figure 6. When the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26 of the housing 20, the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protruding portion 45 each abut against the inner wall 27 of the storage portion, which is the inner wall of the storage portion 26. Specifically, the height of the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protruding portion 45 from the outer peripheral surface 46 is equal to the distance between the outer peripheral surface 46 of the protruding portion 45 and the inner wall 27 of the storage portion, and is slightly higher than the distance between the outer peripheral surface 46 of the protruding portion 45 and the inner wall 27 of the storage portion. For this reason, the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protruding portion 45 each abut against the inner wall 27 of the storage portion.

[0071] At that time, since the sensor housing 41 is made of resin material, the crush ribs 47 elastically deform and slightly crush as they come into contact with the inner wall 27 of the storage section. That is, the crush ribs 47 come into contact with the inner wall 27 of the storage section, elastically deform, and are pressed into the storage section 26 while slightly crushed. In the first embodiment, the protruding portion 45 of the sensor housing 41 has a total of six crush ribs 47: two crush ribs 47 arranged on both sides 46a in the width direction X on the outer peripheral surface 46 of the protruding portion 45, and four crush ribs 47 arranged on both sides 46b in the axial direction Z. When the protruding portion 45 of the sensor housing 41 is stored in the storage section 26 of the housing 20, all six crush ribs 47 arranged on the outer peripheral surface 46 of the protruding portion 45 come into contact with the inner wall 27 of the storage section.

[0072] As a result, the sensor housing 41 is stored in the storage section 26 of the housing 20, with the relative position and orientation of the protruding portion 45 to the storage section 26 being restricted by the crush rib 47, so that the protruding portion 45 is stored in the storage section 26. Therefore, the protruding portion 45 of the sensor housing 41 is stored in the appropriate position and orientation relative to the storage section 26.

[0073] The torque sensor 50 of the steering device 80 includes a stator 60, a magnet 65, and a magnetic collecting yoke 51 (see Figure 9). Of these, the stator 60 is attached to one of the input shaft 83 and output shaft 86 of the steering shaft 82. It is also attached to the other of the input shaft 83 and output shaft 86 of the steering shaft 82 and is positioned inside the stator 60 in the radial direction of the steering shaft 82. In other words, the stator 60 and magnet 65 of the torque sensor 50 are attached separately to the input shaft 83 and the output shaft 86, respectively.

[0074] The torque sensor 50 configured in this way is capable of detecting torque based on the change in magnetism that occurs when the torsion bar 90 twists and the input shaft 83 and output shaft 86 rotate relative to each other.

[0075] Figure 9 is a schematic diagram illustrating the outline of the magnet 65, stator 60, and magnetic collecting yoke 51 of the torque sensor 50. The stator 60 and magnet 65 of the torque sensor 50 are attached to the input shaft 83 on one end and to the output shaft 86 on the other end. In the first embodiment, the magnet 65 is attached to the outer circumferential surface of the input shaft 83, and the stator 60 is attached to the outer circumferential surface of the output shaft 86. The magnet 65 is formed in a substantially cylindrical shape and is an annular permanent magnet in which multiple magnetic poles 66 are arranged alternately in the circumferential direction. In other words, the magnet 65 is a multipole magnet in which different magnetic poles 66, namely N poles 66n and S poles 66s, are arranged alternately in the circumferential direction of the annular magnet 65. In the first embodiment, the magnet 65 is an eight-pole multipole magnet.

[0076] The stator 60 has a flange portion 61 and a teeth portion 62. The teeth portion 62 is the part through which the magnetic flux from the magnet 65 flows, and the flange portion 61 is the part that directs the magnetic flux from the magnet 65 flowing from the teeth portion 62 to the stator 60 to the magnetic collecting yoke 51. The flange portion 61 is formed in an annular plate shape with its thickness direction being axial. The teeth portion 62 extends from the inner circumference of the annular flange portion 61 in the axial direction of the flange portion 61, and is formed in a plate shape with its thickness direction being oriented in the radial direction of the flange portion 61. In addition, multiple teeth portions 62 are arranged in the circumferential direction of the flange portion 61 with intervals between them. The number of teeth portions 62 is the same as the number of magnetic poles 66 that the magnet 65 has.

[0077] The stator 60 formed in this manner has a pair of stators 60 formed of the same shape, namely a first stator 60a and a second stator 60b, and the first stator 60a and the second stator 60b each have a flange portion 61 and a tooth portion 62. That is, the first stator 60a has an annular first flange portion 61a and a plurality of first tooth portions 62a, and the second stator 60b has an annular second flange portion 61b and a plurality of second tooth portions 62b. The first stator 60a and the second stator 60b are mounted on the same shaft in such a way that both flange portions 61 are coaxially positioned and the flange portions 61 are oriented away from the other stator 60. In the first embodiment, both the first stator 60a and the second stator 60b are mounted on the outer circumferential surface of the output shaft 86.

[0078] In other words, the first stator 60a is arranged such that the first teeth portion 62a extends from the first flange portion 61a toward the second stator 60b, and the second stator 60b is arranged such that the second teeth portion 62b extends from the second flange portion 61b toward the first stator 60a. In this case, multiple first teeth portions 62a and second teeth portions 62b are provided on the first flange portion 61a and second flange portion 61b at intervals, so the first stator 60a and the second stator 60b are combined such that the teeth portion 62 of each stator 60 is located in the circumferential direction where the teeth portion 62 of the other stator 60 is not located.

[0079] The magnet 65 attached to the outer circumferential surface of the input shaft 83 is positioned radially inward of the first stator 60a and the second stator 60b, which are combined in this manner. Furthermore, the magnet 65 and the stator 60 are positioned so that their axial directions coincide with the axial directions of the input shaft 83 and the output shaft 86. For these reasons, the magnet 65 and the stator 60 are mounted on the input shaft 83 and the output shaft 86 in such a position that the outer circumferential surface of the magnet 65 faces the teeth portion 62 of the stator 60. In other words, the stator 60 attached to the output shaft 86 has multiple teeth portion 62 through which magnetic flux from the magnet 65 flows in the portion of the output shaft 86 that is in the same position as the magnet 65 attached to the input shaft 83 in the axial direction of the output shaft 86, and the magnet 65 is positioned facing the multiple teeth portion 62 of the stator 60.

[0080] The magnet 65 and the stator 60 are arranged in this relative position. When torque is transmitted between the input shaft 83 and the output shaft 86 via the torsion bar 90, causing the input shaft 83 and the output shaft 86 to rotate slightly relative to each other, the relative position of the magnet 65 and the stator 60 changes, and consequently, the magnetic flux acting from the magnet 65 to the stator 60 changes.

[0081] Furthermore, a magnetic collecting yoke 51 of the torque sensor 50 is positioned near the stator 60. The magnetic collecting yoke 51 is a component for detecting changes in the magnetic flux acting on the stator 60 from the magnet 65, and is fixed to the housing 20 directly or indirectly, and is positioned near the flange portion 61 of the stator 60. Since the stator 60 consists of a pair of first stators 60a and second stators 60b, the magnetic collecting yoke 51 also consists of a pair of first magnetic collecting yoke 51a and second magnetic collecting yoke 51b. Specifically, the first magnetic collecting yoke 51a is positioned near the first flange portion 61a of the first stator 60a, and the second magnetic collecting yoke 51b is positioned near the second flange portion 61b of the second stator 60b.

[0082] The pair of magnetic collecting yokes 51 are located radially outside the teeth portion 62 of the stator 60, between the two flange portions 61 of the stator 60, and overlap with the flange portions 61 of the stator 60 with a gap in the axial direction. In other words, the first magnetic collecting yoke 51a is positioned near the side of the first flange portion 61a of the first stator 60a where the second flange portion 61b is located, and the second magnetic collecting yoke 51b is positioned near the side of the second flange portion 61b of the second stator 60b where the first flange portion 61a is located. These magnetic collecting yokes 51 overlap with the flange portions 61 of the stator 60 within a predetermined range in the circumferential direction. By positioning the magnetic collecting yokes 51 near the flange portions 61 in this way, the magnetic collecting yokes 51 can detect changes in the magnetic flux acting from the magnet 65 to the stator 60 when the input shaft 83 and the output shaft 86 rotate relatively small amounts.

[0083] Furthermore, the pair of magnetic collecting yokes 51 may be positioned such that they sandwich the two flange portions 61 of the pair of stators 60 from both sides in the axial direction. That is, the first magnetic collecting yoke 51a may be positioned near the opposite side of the first flange portion 61a of the first stator 60a from where the second flange portion 61b is located, and the second magnetic collecting yoke 51b may be positioned near the opposite side of the second flange portion 61b of the second stator 60b from where the first flange portion 61a is located. The pair of magnetic collecting yokes 51 may be positioned between the first flange portion 61a and the second flange portion 61b as long as they overlap the flange portions 61 of the stator 60 in a predetermined range in the circumferential direction, and the pair of magnetic collecting yokes 51 may be positioned such that they sandwich the first flange portion 61a and the second flange portion 61b from both sides in the axial direction.

[0084] In this way, by positioning the magnetic collecting yoke 51 near the flange portion 61, the pair of magnetic collecting yokes 51 are able to detect changes in magnetic flux corresponding to changes in the relative positions of the pair of stators 60 and the magnets 65. In other words, the magnetic collecting yoke 51 is able to detect changes in the magnetic flux acting from the magnets 65 to the stators 60 when the input shaft 83 and the output shaft 86 rotate relatively slightly.

[0085] Furthermore, a Hall IC 55 is positioned between the two magnetic yokes 51. The Hall IC 55 is fixed to the housing 20 directly or indirectly, similar to the magnetic yokes 51, and is positioned between the magnetic yokes 51 at a location away from the portion of the magnetic yoke 51 that is near the flange portion 61 of the stator 60. In other words, the Hall IC 55 is sandwiched between the first magnetic yoke 51a and the second magnetic yoke 51b of the magnetic yoke 51. The Hall IC 55 has a Hall element (not shown) that detects changes in magnetic flux detected by the magnetic yokes 51, and an output circuit (not shown) that converts the output voltage output from the Hall element in response to the change in magnetic flux into a digital electrical signal. As a result, the Hall IC 55 can detect changes in magnetic flux density acting on the two magnetic yokes 51, convert the detected change in magnetic flux density into an electrical signal, and output it as an electrical signal. Note that a magnetic sensor that applies the magnetoresistance effect or the tunnel magnetoresistance effect can be used instead of the Hall IC 55. In short, the goal is to be able to output the change in magnetic flux density occurring between the magnetic collecting yokes 51 as an electrical signal.

[0086] The stator 60 is attached to the output shaft 86 by a mounting member 63, as shown in Figure 2, for example. The mounting member 63 is attached to the output shaft 86 and extends from the position where it is attached to the output shaft 86 toward the side where the input shaft 83 is located. By being attached to the mounting member 63 formed in this way, the stator 60 is positioned in the same axial position as the magnet 65 attached to the input shaft 83 in the axial direction, and is positioned radially outward from the magnet 65.

[0087] The reduction gear 102, which transmits power generated by the electric motor 101 to the steering shaft 82, has a worm 103 and a worm wheel 104. The worm 103 is attached to the output shaft of the electric motor 101. The worm wheel 104 is attached to the output shaft 86 of the steering shaft 82 and meshes with the worm 103. As a result, the reduction gear 102 can transmit power generated by the electric motor 101 to the output shaft 86 as auxiliary steering torque via the worm 103 and worm wheel 104.

[0088] Next, the assembly of the steering angle sensor 10 according to the first embodiment will be described. The steering angle sensor 10 is assembled by attaching a driven gear assembly 40, which has a driven gear 15 on which a magnet 16 is positioned and a sensor 18, to a housing 20 on which a steering shaft 82 to which the main gear 11 is attached is located, thereby meshing the driven gear 15 with the main gear 11. In other words, the steering angle sensor 10 is assembled by inserting the protruding portion 45 of the sensor housing 41 of the driven gear assembly 40 into a storage portion 26 formed in the housing 20, thereby meshing the two driven gears 15 held by the sensor housing 41 with the main gear 11.

[0089] In the first embodiment, the protruding portion 45 of the sensor housing 41 of the driven gear assembly 40 has crush ribs 47 arranged on both sides 46a in the width direction X. Therefore, the protruding portion 45 can be inserted into the storage portion 26 of the housing 20 in the appropriate orientation and position, so that the two driven gears 15 can be properly meshed with the main gear 11.

[0090] Figure 10 is an explanatory diagram of the assembly of the driven gear assembly 40 in a configuration in which the sensor housing 41 of the driven gear assembly 40 is not provided with a crush rib 47. When the sensor housing 41 of the driven gear assembly 40 is not provided with a crush rib 47, the protruding portion 45 of the driven gear assembly 40 may have play with the housing portion 26 of the housing 20. In this case, when inserting the protruding portion 45 of the driven gear assembly 40 into the housing portion 26 of the housing 20, it is conceivable that the driven gear assembly 40 may be inserted at an angle relative to the housing portion 26 due to the play.

[0091] If the protruding portion 45 of the driven gear assembly 40 is inserted at an angle into the storage portion 26 of the housing 20, the two driven gears 15 of the driven gear assembly 40 will also be positioned at an angle from their proper positions. In other words, the two driven gears 15 will mesh with the main gear 11 at an angle. In this case, the driven gear assembly 40 may be positioned such that, for example as shown in Figure 10, only one of the two driven gears 15 meshes with the main gear 11, while the other driven gear 15 does not mesh with the main gear 11. In this state, where only one of the two driven gears 15 meshes with the main gear 11, it becomes difficult for the steering angle sensor 10 to properly detect the steering angle.

[0092] Figure 11 is an explanatory diagram of the assembly of the driven gear assembly 40 in the steering angle sensor 10 according to the first embodiment. Figure 12 is an explanatory diagram of the state in which the driven gear 15 of the driven gear assembly 40 shown in Figure 11 meshes with the main gear 11. In the steering angle sensor 10 according to the first embodiment, a crush rib 47 is provided on the protruding portion 45 of the sensor housing 41 of the driven gear assembly 40. Therefore, when inserting the protruding portion 45 of the driven gear assembly 40 into the storage portion 26 of the housing 20, the crush rib 47 comes into contact with the inner wall 27 of the storage portion during insertion. As a result, the protruding portion 45 is inserted into the storage portion 26 while its relative position and orientation to the storage portion 26 are restricted by the crush rib 47. Therefore, the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26 in an appropriate position and orientation.

[0093] In particular, since the crush ribs 47 are also arranged on both sides 46a of the outer circumferential surface 46 of the protruding portion 45 in the width direction X, the protruding portion 45 can be stored in the storage portion 26 at an appropriate angle without the angle viewed in the axial direction Z being tilted, because the crush ribs 47 on both sides 46a in the width direction X abut against the inner wall 27 of the storage portion. Therefore, the two driven gears 15 of the driven gear assembly 40 mesh with the main gear 11 in the appropriate position and orientation, so that both driven gears 15 can mesh with the main gear 11 appropriately.

[0094] Next, the operation of the steering device 80 having the steering angle sensor 10 according to the first embodiment will be described. When the steering wheel 81 is operated while the vehicle equipped with the steering device 80 is being driven, the steering force applied to the steering wheel 81 is transmitted from the steering wheel 81 to the steering shaft 82. The steering force transmitted to the steering shaft 82 is transmitted as steering torque from the steering shaft 82 to the intermediate shaft 92, and from the intermediate shaft 92 to the pinion gear 95a via the pinion shaft 94. As a result, the steering gear 95 having the pinion gear 95a converts the rotational motion transmitted from the pinion gear 95a into linear motion of the rack bar 95b, and operates the tie rod 96.

[0095] Furthermore, the steering device 80 according to the first embodiment has an electric motor 101 that generates auxiliary steering torque to assist the driver's steering. The electric motor 101 generates auxiliary steering torque based on the steering angle detected by the steering angle sensor 10 and the steering torque detected by the torque sensor 50.

[0096] The steering angle sensor 10 detects the rotational state of the steering shaft 82 as the steering angle when the steering wheel 81 is operated and the steering shaft 82 rotates. In other words, when the steering shaft 82 rotates, the steering angle sensor 10 detects that the main gear 11 attached to the steering shaft 82 rotates together with the steering shaft 82, and the rotation of the main gear 11 is transmitted to the driven gear 15, causing the driven gear 15 to rotate as well. When the driven gear 15 rotates, the magnet 16 placed on the driven gear 15 also rotates together with it, and the change in the magnetic flux of the rotating magnet 16 is detected by a sensor 18 placed near the driven gear 15.

[0097] The steering angle sensor 10 detects the rotation angle of the driven gear 15 based on the change in magnetic flux of the magnet 16 detected by the sensor 18, and converts the rotation angle of the driven gear 15 into the rotation angle of the main gear 11 based on the gear ratio between the main gear 11 and the driven gear 15. As a result, the steering angle sensor 10 determines the rotation angle of the steering shaft 82 on which the main gear 11 is located, and detects the rotation angle of the steering shaft 82 as the steering angle of the steering wheel 81 or the steering shaft 82.

[0098] Here, of the two driven gears 15 of the steering angle sensor 10, one driven gear 15 detects the rotational position of the steering shaft 82 in the circumferential direction, and the other driven gear 15 detects the rotational speed of the steering shaft 82. Therefore, the steering angle sensor 10 can detect the current rotational speed and rotational position of the steering shaft 82 in the circumferential direction by the two driven gears 15 that mesh with the main gear 11. Accordingly, the steering angle sensor 10 can detect the current rotational position within the rotational range of the steering shaft 82 as the steering angle of the steering wheel 81 or the steering shaft 82.

[0099] In this way, the steering angle detected by the steering angle sensor 10 is converted into an electrical signal and transmitted to the ECU 100 as an output signal from the steering angle sensor 10. In other words, the steering angle sensor 10 detects the steering angle of the steering shaft 82 by detecting the change in the magnetic flux of the magnet 16 placed on the driven gear 15, which changes with the rotation of the driven gear 15, using the sensor 18, and transmits the detected steering angle as an electrical signal to the ECU 100.

[0100] The torque sensor 50 detects the steering torque applied from the steering wheel 81 to the steering shaft 82 based on the angle of relative rotation when the input shaft 83 and the output shaft 86 rotate relative to each other. That is, since the input shaft 83 and the output shaft 86 are connected via a torsion bar 90, when steering torque is applied to the input shaft 83 of the steering shaft 82, the steering torque is transmitted between the input shaft 83 and the output shaft 86 via the torsion bar 90. At that time, the torsion bar 90 twists slightly, causing the input shaft 83 and the output shaft 86 to rotate relative to each other.

[0101] The torque sensor 50 has a magnet 65 attached to the input shaft 83 and a stator 60 attached to the output shaft 86. Therefore, when the input shaft 83 and the output shaft 86 rotate relative to each other, the magnet 65 and stator 60 of the torque sensor 50 also rotate relative to each other. The angle of relative rotation between the magnet 65 and the stator 60 increases as the steering torque acting between the input shaft 83 and the output shaft 86 increases.

[0102] When the magnet 65 and the stator 60 rotate relative to each other, the magnetic flux acting from the magnet 65 to the stator 60 changes. The magnetic collecting yoke 51, positioned near the stator 60, is capable of detecting changes in the magnetic flux acting from the magnet 65 to the stator 60. Therefore, when the magnet 65 and the stator 60 rotate relative to each other due to the relative rotation of the input shaft 83 and the output shaft 86, the magnetic collecting yoke 51 positioned near the stator 60 can detect changes in the magnetic flux acting from the magnet 65 to the stator 60.

[0103] The magnetic flux acting from the magnet 65 on the stator 60, as detected by the magnetic collecting yoke 51, changes according to the angle of relative rotation between the magnet 65 and the stator 60. The Hall IC 55 detects the magnetic flux that changes according to the angle of relative rotation between the magnet 65 and the stator 60, as detected by the magnetic collecting yoke 51, using a Hall element, and converts it into an electrical signal in its output circuit, which is then transmitted to the ECU 100 as an output signal from the torque sensor 50. In other words, the torque sensor 50 detects the steering torque applied to the input shaft 83 by detecting the change in magnetic flux acting from the magnet 65 on the stator 60 using the magnetic collecting yoke 51 and the Hall IC 55, and transmits the detected steering torque as an electrical signal to the ECU 100.

[0104] The ECU 100 operates the electric motor 101 based on the steering angle transmitted from the steering angle sensor 10 and the steering torque transmitted from the torque sensor 50, generating auxiliary steering torque in the electric motor 101. In other words, the ECU 100 adjusts the power value supplied to the electric motor 101 based on the steering angle transmitted from the steering angle sensor 10 and the steering torque transmitted from the torque sensor 50, generating auxiliary steering torque in the electric motor 101 corresponding to the transmitted steering angle and steering torque.

[0105] Specifically, the ECU 100 acquires a steering angle signal from the steering angle sensor 10, a steering torque signal from the torque sensor 50, a vehicle speed signal from the vehicle speed sensor 105, and operational information of the electric motor 101 from a rotation detection device provided on the electric motor 101. Based on this operational information, the steering angle, steering torque, and vehicle speed signals, the ECU 100 generates auxiliary steering torque in the electric motor 101. The auxiliary steering torque generated by the electric motor 101 is transmitted to the output shaft 86 of the steering shaft 82 via the worm 103 and worm wheel 104 of the reduction gear 102. As a result, the steering force applied by the driver to the steering wheel 81 is assisted by the auxiliary steering torque generated by the electric motor 101.

[0106] As described above, the steering angle sensor 10 according to the first embodiment has a driven gear assembly 40 having two driven gears 15 that mesh with the main gear 11, and the driven gear assembly 40 has a plurality of crush ribs 47 that abut against the inner wall 27 of the storage section 26 on both sides 46a of the outer circumferential surface 46 of the protruding portion 45 that is stored in the storage section 26, in the direction in which the two driven gears 15 are aligned. Therefore, the driven gear assembly 40 can store the protruding portion 45 in the storage section 26 without the angle of the protruding portion 45 tilting from an appropriate angle when viewed in the axial direction Z.

[0107] This allows the two driven gears 15 of the driven gear assembly 40 to mesh with the main gear 11 in the appropriate position and orientation, and prevents the driven gears 15 from failing to mesh with the main gear 11 due to the inclination of the protrusion 45. Therefore, both of the two driven gears 15 of the driven gear assembly 40 can be properly meshed with the main gear 11, and the steering angle can be accurately detected using the two driven gears 15 that mesh with the main gear 11. As a result, it is possible to prevent difficulties in properly detecting the steering angle.

[0108] Furthermore, since the crush rib 47 has a tapered portion 47a that decreases in height from the outer circumferential surface 46 of the protrusion 45 towards the end 45a of the protrusion 45, the crush rib 47 can be pressed into the housing 26 while being guided by the tapered portion 47a when inserting the protrusion 45 into the housing 26. This improves the ease of assembling the driven gear assembly 40 to the housing 20 when the crush rib 47 is provided on the protrusion 45 in order to properly mesh the driven gear 15 with the main gear 11. As a result, the ease of assembly of the steering angle sensor 10 can be improved.

[0109] [Second Embodiment] Next, the steering angle sensor 10 according to the second embodiment will be described. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. The following description will focus on the differences from the first embodiment.

[0110] Figure 13 is a side view of the steering angle sensor 10 according to the second embodiment. Figure 14 is a perspective view of the driven gear assembly 40 and stator 60 in the steering angle sensor 10 according to the second embodiment. Figure 15 is a view taken along the line C-C in Figure 13. In the second embodiment, the steering angle sensor 10 is integrally formed with the torque sensor 50. Specifically, the steering angle sensor 10, similar to the first embodiment, includes a main gear 11 attached to the steering shaft 82, two driven gears 15 that mesh with the main gear 11, a sensor housing 41 that holds the two driven gears 15, and a driven gear assembly 40 having the driven gears 15 and the sensor housing 41. The sensor housing 41 has a protruding portion 45 that is housed in a storage portion 26 of the housing 20 that covers the portion of the steering shaft 82 where the main gear 11 is located, and a plurality of crush ribs 47 that abut against the inner wall 27 of the storage portion are arranged on the outer circumferential surface 46 of the protruding portion 45.

[0111] Furthermore, the torque sensor 50 has a stator 60 and a magnet 65, the stator 60 is attached to the output shaft 86 as in the first embodiment, and the magnet 65 is attached to the input shaft 83. In the second embodiment, unlike the first embodiment, the main gear 11 of the steering angle sensor 10 is attached to the stator 60 of the torque sensor 50 and is attached to the steering shaft 82 via the stator 60.

[0112] More specifically, the main gear 11 is mounted on the outer circumferential surface of the teeth portion 62 of the stator 60 and positioned between the first flange portion 61a of the first stator 60a and the second flange portion 61b of the second stator 60b. The outer diameter of the main gear 11 is smaller than the outer diameters of the first flange portion 61a and the second flange portion 61b. For this reason, the first flange portion 61a and the second flange portion 61b of the stator 60 protrude radially outward from the main gear 11 mounted on the outer circumferential surface of the teeth portion 62.

[0113] In the second embodiment, the main gear 11 of the steering angle sensor 10 is attached to the stator 60 of the torque sensor 50, and since the stator 60 is attached to the steering shaft 82, the main gear 11 is attached to the steering shaft 82 via the stator 60. In the second embodiment, since the stator 60 is attached to the output shaft 86 of the steering shaft 82, the main gear 11 is also attached to the output shaft 86 via the stator 60.

[0114] The driven gear 15 of the driven gear assembly 40 has a thickness in the axial direction Z that is smaller than the distance in the axial direction Z between the first flange portion 61a and the second flange portion 61b of the stator 60 to which the main gear 11 is attached.

[0115] Furthermore, the driven gear assembly 40 is positioned such that the driven gear 15 is in the same position as the main gear 11 in the axial Z direction. In other words, the storage section 26 of the housing 20, in which the driven gear assembly 40 is housed, is formed in a position that allows the driven gear assembly 40 to be positioned such that the driven gear 15 is in the same position as the main gear 11 in the axial Z direction.

[0116] As a result, the two driven gears 15 of the driven gear assembly 40 insert their protrusions 45 into the storage portion 26 of the housing 20, causing the driven gears 15 to fit between the first flange portion 61a and the second flange portion 61b of the stator 60, and mesh with the main gear 11 at a position between the first flange portion 61a and the second flange portion 61b.

[0117] In the second embodiment, the magnetic collecting yoke 51 of the torque sensor 50 is positioned on the driven gear assembly 40 of the steering angle sensor 10. That is, the magnetic collecting yoke 51 is positioned inside the protrusion 45 of the sensor housing 41 and held by the sensor housing 41, similar to the driven gear 15 and sensor 18 of the steering angle sensor 10. Similarly, the Hall IC 55 (see Figure 9) of the torque sensor 50 is also positioned inside the protrusion 45 of the sensor housing 41 and held by the sensor housing 41.

[0118] The magnetic collecting yoke 51, held by the sensor housing 41, has a portion of it exposed to the outside of the sensor housing 41 from the inside of the protrusion 45, similar to the driven gear 15. The magnetic collecting yoke 51 is positioned between the two driven gears 15 in the width direction X, and is exposed to the outside of the sensor housing 41 from the inside of the protrusion 45 at the position between the two driven gears 15.

[0119] When the protruding portion 45 of the driven gear assembly 40 is inserted into the storage portion 26 of the housing 20, and the driven gear 15 is meshed with the main gear 11, the magnetic collecting yoke 51 held by the sensor housing 41 is positioned to overlap with the first flange portion 61a and the second flange portion 61b of the stator 60 on which the main gear 11 is located, while being separated in the axial Z direction. As a result, the magnetic collecting yoke 51 can detect changes in the magnetic flux acting on the stator 60 from the magnet 65 (see Figure 9).

[0120] In the steering angle sensor 10 according to the second embodiment, similar to the steering angle sensor 10 according to the first embodiment, the protruding portion 45 of the driven gear assembly 40 is inserted into the storage portion 26 of the housing 20 during assembly. This engages the two driven gears 15 of the driven gear assembly 40 with the main gear 11, which is attached to the steering shaft 82 located inside the housing 20. At this time, since the protruding portion 45 of the sensor housing 41 of the driven gear assembly 40 has crush ribs 47 on both sides 46a in the width direction X, the protruding portion 45 can be inserted into the storage portion 26 in the appropriate orientation and position, and the two driven gears 15 can be properly engaged with the main gear 11.

[0121] Furthermore, in the second embodiment, the driven gear assembly 40 has a magnetizing yoke 51 for the torque sensor 50. Therefore, by inserting the protruding portion 45 of the driven gear assembly 40 into the storage portion 26 of the housing 20, the magnetizing yoke 51 of the driven gear assembly 40 can be positioned to overlap with the flange portion 61 of the stator 60 attached to the steering shaft 82.

[0122] In this configuration, the projection 45 of the sensor housing 41 of the driven gear assembly 40 has crush ribs 47 on both sides 46b in the axial direction Z. Therefore, the projection 45 can be inserted into the storage portion 26 of the housing 20 in an appropriate position and orientation in the axial direction Z. This allows the magnetic collecting yoke 51 of the driven gear assembly 40 to be positioned near the flange portion 61 of the stator 60 attached to the steering shaft 82, at an appropriate distance in the axial direction Z, but also at a distance from the flange portion 61.

[0123] As described above, in the steering angle sensor 10 according to the second embodiment, the main gear 11 is attached to the stator 60 of the torque sensor 50 which is attached to the steering shaft 82, and the main gear 11 is attached to the steering shaft 82 via the stator 60. This allows the assembly of the steering angle sensor 10 and the torque sensor 50 to be performed simultaneously, simplifying the manufacturing process. As a result, manufacturing costs can be reduced.

[0124] Furthermore, by attaching the main gear 11 to the stator 60 of the torque sensor 50, the steering angle sensor 10 and the torque sensor 50 can be integrated, thereby enabling miniaturization of both the steering angle sensor 10 and the torque sensor 50. As a result, the steering device 80 having the steering angle sensor 10 and the torque sensor 50 can be miniaturized.

[0125] Furthermore, the projection 45 of the driven gear assembly 40 has a plurality of crush ribs 47 on the outer circumferential surface 46 of the projection 45, on both sides 46b in the axial direction Z of the steering shaft 82. This allows the projection 45 to be inserted into the storage portion 26 of the housing 20 in an appropriate position and orientation in the axial direction Z. As a result, the magnetic collecting yoke 51, which is arranged in the driven gear assembly 40, can be positioned at an appropriate distance from the flange portion 61 of the stator 60 in the axial direction Z. Therefore, the detection accuracy when detecting changes in magnetic flux from the stator 60 with the magnetic collecting yoke 51 can be improved. Consequently, the detection accuracy of the steering torque by the torque sensor 50 can be improved.

[0126] Furthermore, since the magnetic collecting yoke 51 can be positioned at an appropriate distance from the flange portion 61 of the stator 60, contact between the magnetic collecting yoke 51 and the flange portion 61 can be suppressed. For example, when an impact is input to the tires while the vehicle is running, and the impact is input to the steering shaft 82 via the tie rod 96, steering gear 95, etc., the steering shaft 82 moves axially Z, and the stator 60 located on the steering shaft 82 also moves axially Z. When the stator 60 moves axially, the flange portion 61 of the stator 60 moves relative to the magnetic collecting yoke 51 in the axial direction Z. In such a case, if the distance between the flange portion 61 of the stator 60 and the magnetic collecting yoke 51 in the axial direction Z is narrow, there is a possibility that the flange portion 61 of the stator 60 and the magnetic collecting yoke 51 will come into contact. In this case, if a large force is applied to the flange portion 61 of the stator 60 and the magnetic collecting yoke 51, the flange portion 61 or the magnetic collecting yoke 51 may be damaged. If the flange portion 61 or the magnetic collecting yoke 51 is damaged, the magnetic collecting yoke 51 will no longer be able to detect changes in magnetic flux from the stator 60 with high accuracy. In this case, the torque sensor 50 will no longer be able to detect steering torque with high accuracy.

[0127] In contrast, in the second embodiment, the crush ribs 47 arranged on both sides in the axial direction Z of the protruding portion 45 of the driven gear assembly 40 allow the magnetic collecting yoke 51, which is located on the driven gear assembly 40, to be positioned at an appropriate distance from the flange portion 61 of the stator 60. Therefore, even if an impact is input to the steering shaft 82, contact between the flange portion 61 of the stator 60 and the magnetic collecting yoke 51 can be suppressed, and damage to the flange portion 61 and the magnetic collecting yoke 51 can be suppressed. As a result, steering torque can be detected with high accuracy over a long period of time.

[0128] [Third Embodiment] Next, the steering angle sensor 10 according to the third embodiment will be described. Components identical to those in the first embodiment are given the same reference numerals and their descriptions are omitted. The following description will focus on the differences from the first embodiment.

[0129] Figure 16 is a plan view of the driven gear assembly 40 in the steering angle sensor 10 according to the third embodiment. In the third embodiment, the crush rib 47 arranged on the outer peripheral surface 46 of the protrusion 45 of the sensor housing 41 in the driven gear assembly 40 has a length Lr of the crush rib 47 in the longitudinal direction Y that is shorter than the length Lp of the protrusion 45 in the longitudinal direction Y. In other words, the length Lr of the crush rib 47 in the insertion direction of the protrusion 45 into the storage portion 26 of the housing 20 is shorter than the length Lp of the protrusion 45 in the insertion direction. In this case, the length Lp of the protrusion 45 is the length of the longest part of the protrusion 45 in the longitudinal direction Y.

[0130] Multiple crush ribs 47 are arranged on the protruding portion 45, but the length Lr of all crush ribs 47 arranged on the protruding portion 45 is shorter than the length Lp of the protruding portion 45. In the third embodiment, the multiple crush ribs 47 arranged on the protruding portion 45 are all formed with a length Lr in the longitudinal direction Y that is approximately the same.

[0131] Figure 17 is a schematic diagram showing the state in which the protruding portion 45 of the driven gear assembly 40 shown in Figure 16 is stored in the storage portion 26 of the housing 20. In the third embodiment, since the length Lr of the crush rib 47 is shorter than the length Lp of the protruding portion 45, when the protruding portion 45 of the driven gear assembly 40 is stored in the storage portion 26 of the housing 20, the crush rib 47 abuts against the inner wall 27 of the storage portion 27 for a length shorter than the length Lp of the protruding portion 45 in the direction of insertion of the protruding portion 45 into the storage portion 26. That is, when the protruding portion 45 of the sensor housing 41 of the driven gear assembly 40 is stored in the storage portion 26 of the housing 20, the contact length Lc of the crush rib 47 against the inner wall 27 of the storage portion 27 is shorter than the length Lp of the protruding portion 45.

[0132] In the third embodiment, the driven gear assembly 40 includes a seal member arrangement portion 44 where an O-ring 70, which is a sealing member, is arranged. The seal member arrangement portion 44 is positioned closer to the flange portion 42 relative to the protrusion portion 45 in the longitudinal direction Y. The width of the seal member arrangement portion 44 in the width direction X and the width in the axial direction Z are both larger and smaller than that of the protrusion portion 45. In other words, the size of the seal member arrangement portion 44 when the sensor housing 41 is viewed in the longitudinal direction Y is larger than that of the protrusion portion 45 around the entire circumference of the seal member arrangement portion 44. For this reason, the seal member arrangement portion 44 and the protrusion portion 45 are formed with a step difference.

[0133] The housing 20 has a seal member contact portion 25 on the radially outer side of the housing 20 relative to the storage portion 26, where the O-ring 70, which is arranged in the seal member arrangement portion 44 of the driven gear assembly 40, abuts against its inner circumferential surface. That is, the seal member contact portion 25 is located on the entrance side of the storage portion 26 in the insertion direction of the driven gear assembly 40 into the storage portion 26. The seal member contact portion 25 is formed in a hole-like shape that opens radially, similar to the storage portion 26, but the size of the hole is larger than that of the storage portion 26. For this reason, the storage portion inner wall 27, which is the inner wall of the storage portion 26, and the seal member contact portion 25 are formed with a step difference between them.

[0134] In the third embodiment, the driven gear assembly 40 has an O-ring 70, which is a sealing member, placed in the sealing member placement portion 44 of the sensor housing 41, with the protruding portion 45 housed inside the storage portion 26. Since the O-ring 70 is an annular member made of rubber material, the annular O-ring 70 is placed around the entire circumference of the sealing member placement portion 44 of the sensor housing 41 when the sensor housing 41 is viewed in the longitudinal direction Y.

[0135] On the other hand, the housing 20 has a sealing member contact portion 25 on the inlet side of the storage portion 26 in the insertion direction when inserting the protruding portion 45 into the storage portion 26. Therefore, when the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26 of the housing 20, the O-ring 70 placed in the sealing member arrangement portion 44 of the sensor housing 41 comes into contact with the inner circumferential surface of the sealing member contact portion 25.

[0136] The O-ring 70 of the driven gear assembly 40 is positioned in the seal member arrangement portion 44 of the sensor housing 41 in this manner, and contacts both the seal member arrangement portion 44 of the sensor housing 41 and the seal member contact portion 25 of the housing 20 at a position on the inlet side of the storage portion 26 in the insertion direction when inserting the protruding portion 45 into the storage portion 26. As a result, the O-ring 70 ensures a seal between the sensor housing 41 and the housing 20 at a position on the inlet side of the storage portion 26 in the insertion direction when inserting the protruding portion 45 into the storage portion 26.

[0137] As described above, in the steering angle sensor 10 according to the third embodiment, the crush rib 47 contacts the inner wall 27 of the storage section 26 with a length Lc shorter than the length Lp of the protruding portion 45 in the insertion direction of the protruding portion 45 into the storage section 26. Therefore, when inserting the protruding portion 45 into the storage section 26 while deforming the crush rib 47, insertion can be performed with less force compared to the case where the contact length Lc is long. This makes it easier to assemble the steering angle sensor 10 by inserting the protruding portion 45 of the driven gear assembly 40 into the storage section 26 of the housing 20, thereby improving the ease of assembly of the steering angle sensor 10. As a result, the manufacturing cost of the steering angle sensor 10 can be reduced.

[0138] Furthermore, since the length Lr of the crush rib 47 in the insertion direction of the protrusion 45 into the storage section 26 of the housing 20 is shorter than the length Lp of the protrusion 45 in the same direction, the contact length Lc of the crush rib 47 against the inner wall 27 of the storage section can be made shorter than the length Lp of the protrusion 45. As a result, when inserting the protrusion 45 into the storage section 26 while deforming the crush rib 47, insertion can be done with less force, improving the ease of assembly of the steering angle sensor 10. Consequently, the manufacturing cost of the steering angle sensor 10 can be reduced.

[0139] Furthermore, the driven gear assembly 40 is provided with a seal member placement section 44, the housing 20 has a seal member contact section 25, and the O-ring 70 contacts both the seal member placement section 44 and the seal member contact section 25 at a position closer to the entrance of the storage section 26 in the insertion direction of the protruding portion 45 into the storage section 26 of the housing 20. This ensures that sealing between the sensor housing 41 and the housing 20 is maintained at a position closer to the entrance of the storage section 26 in the insertion direction when inserting the protruding portion 45 into the storage section 26, thereby preventing water from entering the storage section 26 from the entrance side. Consequently, water entering the inside of the housing 20 can be prevented, and the reduction in steering angle detection accuracy due to water adhering to the steering angle sensor 10 can be prevented. As a result, the steering angle can be detected with high accuracy over a long period of time.

[0140] [Fourth Embodiment] Next, the steering angle sensor 10 according to the fourth embodiment will be described. Components identical to those in the first and third embodiments are denoted by the same reference numerals and their descriptions are omitted. The following description will focus on the differences from the first and third embodiments.

[0141] Figure 18 is a cross-sectional view of the housing 20 of the steering angle sensor 10 according to the fourth embodiment. The housing 20 of the steering angle sensor 10 according to the fourth embodiment has a storage portion 26 and a sealing member contact portion 25, similar to the third embodiment. Unlike the third embodiment, the storage portion 26 has a storage portion inner wall 27 which is the inner wall of the storage portion 26, and has a tapered portion 31 and a flat portion 32.

[0142] The tapered portion 31 of the inner wall 27 of the storage section is inclined with respect to the length direction Y, and the direction of inclination is such that the opening area of ​​the storage section 26 decreases when viewed in the length direction Y, from the side where the seal member contact portion 25 is located toward the side where the inner circumferential surface 21 of the housing 20 is located. The flat portion 32 of the inner wall 27 of the storage section is located on the opposite side of the tapered portion 31 from the side where the seal member contact portion 25 is located, and is an inner wall formed parallel to the length direction Y.

[0143] Furthermore, in the fourth embodiment, the length of the crush rib 47 positioned on the protruding portion 45 of the sensor housing 41 is the same as the length of the portion of the protruding portion 45 where the crush rib 47 is positioned, as in the first embodiment (see Figure 4).

[0144] Figure 19 is a schematic diagram showing the state in which the protruding portion 45 of the driven gear assembly 40 is stored in the storage portion 26 of the housing 20 in the fourth embodiment. When attaching the driven gear assembly 40 to the housing 20, in the fourth embodiment as in the third embodiment, the protruding portion 45 of the sensor housing 41 of the driven gear assembly 40 is inserted into the storage portion 26 in a direction that protrudes from the flange portion 42 toward the side where the storage portion 26 of the housing 20 is located in the longitudinal direction Y. When the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26 of the housing 20, the multiple crush ribs 47 arranged on the outer peripheral surface 46 of the protruding portion 45 each abut against the inner wall 27 of the storage portion 26, which is the inner wall of the storage portion 26.

[0145] In this fourth embodiment, the inner wall 27 of the storage section 26 has a tapered portion 31 that is inclined with respect to the length direction Y and a flat portion 32 that is formed parallel to the length direction Y. The tapered portion 31 that is inclined with respect to the length direction Y is inclined such that when the protrusion 45 of the sensor housing 41 is stored in the storage section 26, the distance between the inner wall 27 of the storage section and the outer peripheral surface 46 of the protrusion 45 decreases as you move from the opening side of the storage section 26 towards the back side in the insertion direction when inserting the protrusion 45 into the storage section 26. In other words, the tapered portion 31 of the inner wall 27 of the storage section has a tapered inner wall in which the distance between the inner wall 27 of the storage section and the outer peripheral surface 46 of the protrusion 45 decreases as you move from the side where the seal member contact portion 25 is located in the length direction Y towards the side where the inner peripheral surface 21 of the housing 20 (see Figure 18) is located.

[0146] The flat portion 32 is located further back than the tapered portion 31 in the insertion direction when inserting the protruding portion 45 into the storage portion 26. That is, the flat portion 32 is positioned on the side of the inner circumferential surface 21 of the housing 20 (see Figure 18) relative to the tapered portion 31 in the longitudinal direction Y.

[0147] Furthermore, since the flat portion 32 is formed parallel to the length direction Y, when the protruding portion 45 of the sensor housing 41 is stored in the storage portion 26, the distance between the inner wall 27 of the storage portion 26 and the outer circumferential surface 46 of the protruding portion 45 is constant. That is, the flat portion 32 maintains a constant distance from the outer circumferential surface 46 of the protruding portion 45 and is formed as an inner wall substantially parallel to the outer circumferential surface 46 of the protruding portion 45.

[0148] Thus, the distance between the flat portion 32, which is formed parallel to the outer circumferential surface 46 of the protrusion 45, and the outer circumferential surface 46 of the protrusion 45 is approximately the same as the height of the crush rib 47 from the outer circumferential surface 46 of the protrusion 45, and is slightly smaller than the height of the crush rib 47. For this reason, when the protrusion 45 of the sensor housing 41 is stored in the storage portion 26, the crush rib 47 positioned on the outer circumferential surface 46 of the protrusion 45 comes into contact with the inner wall 27 of the storage portion at the flat portion 32.

[0149] Therefore, in the fourth embodiment, the contact length Lc of the crush rib 47 against the inner wall 27 of the storage section is the length of the flat portion 32 of the inner wall 27 in the longitudinal direction Y. Since the flat portion 32 of the inner wall 27 of the storage section is a part of the inner wall 27 in the longitudinal direction Y, the contact length Lc of the crush rib 47 against the inner wall 27, which is the contact length between the crush rib 47 and the flat portion 32, is shorter than the length Lp of the protruding portion 45 of the sensor housing 41.

[0150] As described above, in the steering angle sensor 10 according to the fourth embodiment, the inner wall 27 of the storage portion 26 of the housing 20 has a tapered portion 31 and a flat portion 32 located further back than the tapered portion 31 in the insertion direction of the protruding portion 45 into the storage portion 26, and the crush rib 47 arranged on the outer peripheral surface 46 of the protruding portion 45 abuts against the inner wall 27 of the storage portion at the flat portion 32. As a result, the contact length Lc of the crush rib 47 against the inner wall 27 of the storage portion can be made shorter than the length Lp of the protruding portion 45 of the sensor housing 41, so that when inserting the protruding portion 45 into the storage portion 26 while deforming the crush rib 47, insertion can be done with less force.

[0151] Furthermore, since the inner wall 27 of the storage section has a tapered portion 31 on the side of the entrance to the storage section 26 that is closer to the entrance than the flat portion 32, it is possible to easily insert the protruding portion 45 of the driven gear assembly 40 into the storage section 26 of the housing 20. In other words, when inserting the protruding portion 45 into the storage section 26, the crush rib 47, which is arranged on the outer peripheral surface 46 of the protruding portion 45, can be guided by the tapered portion 31 and pressed into the flat portion 32. This improves the ease of assembling the driven gear assembly 40 to the housing 20 when the crush rib 47 is provided on the protruding portion 45 to position the driven gear assembly 40 relative to the housing 20. As a result, the ease of assembly of the steering angle sensor 10 can be improved, and the manufacturing cost of the steering angle sensor 10 can be reduced.

[0152] Furthermore, since the crush rib 47 contacts the inner wall 27 of the storage section at the flat portion 32 located further back than the tapered portion 31, the crush rib 47 can contact the inner wall 27 of the storage section at a position away from the seal member placement portion 44. As a result, even if the protruding portion 45 deforms due to the crush rib 47 contacting the inner wall 27 of the storage section, the deformation of the protruding portion 45 is less likely to affect the seal member placement portion 44, thereby suppressing a decrease in the sealing performance of the O-ring 70.

[0153] In other words, since the crush rib 47 contacts the inner wall 27 of the storage section while undergoing elastic deformation, when the protruding portion 45 is inserted into the storage section 26, the reaction force of the crush rib 47 is transmitted to the protruding portion 45, which may cause the protruding portion 45 to deform slightly. If the protruding portion 45 deforms, the seal member placement portion 44 may also deform along with the deformation of the protruding portion 45. If the seal member placement portion 44 deforms, the way the O-ring 70, which contacts both the seal member placement portion 44 and the seal member contact portion 25, is compressed may change in accordance with the deformation of the seal member placement portion 44. In this case, the sealing performance of the O-ring 70 may decrease.

[0154] In contrast, in the fourth embodiment, the crush rib 47 can be brought into contact with the inner wall 27 of the storage section at a position away from the seal member placement section 44. Therefore, even if the protruding portion 45 deforms due to the crush rib 47 contacting the inner wall 27 of the storage section, the seal member placement section 44 is less likely to deform, and the reduction in sealing performance of the O-ring 70 can be suppressed. Consequently, the deformation of the seal member placement section 44 caused by the deformation of the protruding portion 45 due to the crush rib 47 contacting the inner wall 27 of the storage section can be suppressed, and the way the O-ring 70 is crushed in the seal member placement section 44 of the driven gear assembly 40 can be made appropriate. As a result, the sealing performance of the O-ring 70 can be improved.

[0155] [Modification] In the fourth embodiment described above, the inner wall 27 of the storage section 26 has a tapered portion 31 and a flat portion 32, so that the crush rib 47, which is arranged on the protruding portion 45 of the driven gear assembly 40, comes into contact with a part of the inner wall 27 of the storage section in the longitudinal direction Y. However, the inner wall 27 of the storage section may have portions other than the tapered portion 31 and the flat portion 32.

[0156] Figure 20 is a schematic diagram showing a modified example of the steering angle sensor 10 according to the fourth embodiment, in which the inner wall 27 of the storage section has an enlarged diameter section 36 and a reduced diameter section 37. The inner wall 27 of the storage section 26 of the housing 20 may have an enlarged diameter section 36 and a reduced diameter section 37, for example, as shown in Figure 20, at different distances from the outer circumferential surface 46 of the protruding section 45. In this case, the enlarged diameter section 36 of the inner wall 27 of the storage section is located on the opening side of the storage section 26 in the direction in which the protruding section 45 is inserted into the storage section 26, relative to the reduced diameter section 37, and is formed parallel to the outer circumferential surface 46, spaced apart from the outer circumferential surface 46 of the protruding section 45. In other words, the enlarged diameter section 36 is located on the side of the reduced diameter section 37 in the longitudinal direction Y where the seal member contact section 25 is located.

[0157] Furthermore, the reduced-diameter portion 37 of the inner wall 27 of the storage section is located further back than the expanded-diameter portion 36 in the direction of insertion of the protruding portion 45 into the storage section 26, and is formed such that the distance from the outer circumferential surface 46 of the protruding portion 45 is smaller than the distance between the expanded-diameter portion 36 and the outer circumferential surface 46 of the protruding portion 45. In other words, the reduced-diameter portion 37 is positioned on the side of the length direction Y where the inner circumferential surface 21 of the housing 20 (see Figure 18) is located relative to the expanded-diameter portion 36, and is formed parallel to the outer circumferential surface 46 of the protruding portion 45, at a distance smaller than the distance between the expanded-diameter portion 36 and the outer circumferential surface 46 of the protruding portion 45.

[0158] As described above, a step portion 35 is formed between the enlarged diameter portion 36 and the reduced diameter portion 37, which are at different distances from the outer peripheral surface 46 of the protruding portion 45, and the enlarged diameter portion 36 and the reduced diameter portion 37 of the inner wall 27 of the storage portion are connected by the step portion 35. The crush rib 47 abuts against the inner wall 27 of the storage portion, which has an enlarged diameter portion 36 and a reduced diameter portion 37, at the reduced diameter portion 37. For this reason, the contact length Lc of the crush rib 47 against the inner wall 27 of the storage portion is the length of the reduced diameter portion 37 of the inner wall 27 of the storage portion in the longitudinal direction Y. Since the reduced diameter portion 37 of the inner wall 27 of the storage portion is a part of the inner wall 27 of the storage portion in the longitudinal direction Y, the contact length Lc of the crush rib 47 against the inner wall 27 of the storage portion, which is the contact length between the crush rib 47 and the reduced diameter portion 37, is shorter than the length Lp of the protruding portion 45 of the sensor housing 41.

[0159] The inner wall 27 of the storage section, which has an enlarged diameter portion 36 and a reduced diameter portion 37, is formed, for example, by cutting the inner wall 27 of the storage section to create the enlarged diameter portion 36. In other words, the inner wall 27 of the storage section is formed by first creating a storage section 26 with a flat inner wall 27 by casting, and then cutting the portion of the inner wall 27 of the storage section near the seal member contact portion 25 to create the enlarged diameter portion 36. This creates an inner wall 27 of the storage section that has an enlarged diameter portion 36 and a reduced diameter portion 37, which are at different distances from the protruding portion 45 of the driven gear assembly 40.

[0160] Thus, the inner wall 27 of the storage portion 26 of the housing 20 has an enlarged diameter portion 36 and a reduced diameter portion 37, and the crush rib 47 arranged on the outer peripheral surface 46 of the protruding portion 45 contacts the inner wall 27 of the storage portion at the reduced diameter portion 37. As a result, the crush rib 47 can contact the inner wall 27 of the storage portion at a position away from the seal member arrangement portion 44. Therefore, even if the protruding portion 45 deforms due to the crush rib 47 contacting the inner wall 27 of the storage portion, the deformation of the protruding portion 45 is less likely to affect the seal member arrangement portion 44, and the deformation of the seal member arrangement portion 44 accompanying the deformation of the protruding portion 45 can be suppressed. This makes it possible to make the way the O-ring 70 arranged in the seal member arrangement portion 44 of the driven gear assembly 40 is crushed appropriate. As a result, the sealing performance of the O-ring 70 can be improved.

[0161] Furthermore, in each of the embodiments described above, the crush ribs 47 of the projection 45 of the driven gear assembly 40 are arranged one on each of the side surfaces 46a on the outer circumferential surface 46 of the projection 45 in the width direction X, but the number of crush ribs 47 may be other than this. The number of crush ribs 47 arranged on both side surfaces 46a of the projection 45 in the width direction X is not limited as long as both of the two driven gears 15 of the driven gear assembly 40 can mesh with the main gear 11.

[0162] Furthermore, in each of the embodiments described above, the crush ribs 47 on the protruding portion 45 of the driven gear assembly 40 are arranged in pairs on each of the side surfaces 46b in the axial direction Z, but the number of crush ribs 47 may be other than this. When the steering angle sensor 10 and the torque sensor 50 are formed as an integrated unit, the number of crush ribs 47 arranged on both side surfaces 46b of the protruding portion 45 in the axial direction Z is not limited as long as the magnetic collecting yoke 51 of the driven gear assembly 40 is positioned at an appropriate distance from the flange portion 61 of the stator 60 in the axial direction Z.

[0163] While preferred embodiments of this disclosure have been described above, this disclosure is not limited to those described in the embodiments described above. The configurations described as embodiments and modifications may be combined as appropriate.

[0164] 10 Steering angle sensor 11 Main gear 11a Body part 11b Mounting part 11c Support member 15 Driven gear 16 Magnet 18 Sensor 20 Housing 21 Inner circumferential surface 25 Seal member contact part 26 Storage part 27 Inner wall of storage part 31 Tapered part 32 Flat part 35 Stepped part 36 Enlarged diameter part 37 Reduced diameter part 40 Driven gear assembly 41 Sensor housing 42 Flange part 43 Connector part 44 Seal member arrangement part 45 Protruding part 46 Outer circumferential surface 46a, 46b Side surface 47 Crush rib 47a Tapered part 50 Torque sensor 51 Magnetic collecting yoke 55 Hall IC 60 Stator 61 Flange part 62 Teeth part 65 Magnet 70 O-ring 80 Steering system 81 Steering wheel 82 Steering shaft 83 Input shaft 86 Output shaft 90 Torsion bar 91, 93 Universal joint 92 Intermediate shaft 94 Pinion shaft 95 Steering gear 95a Pinion gear 95b Rack bar 96 Tie rod 100 ECU 101 Electric motor 102 Reduction gear 103 Worm 104 Worm wheel 105 Vehicle speed sensor 108 Ignition switch 109 Power supply

Claims

1. A steering angle sensor comprising: a driven gear assembly having an annular main gear mounted on a shaft that rotates with a steering wheel and rotates integrally with the shaft; two driven gears that mesh with the main gear; and a sensor for detecting the rotation of the driven gears; and a housing that covers the portion of the shaft on which the main gear is located, wherein the housing has a storage portion for storing the driven gear assembly; the driven gear assembly has a protruding portion that is stored inside the storage portion; the two driven gears are arranged side by side inside the protruding portion with their respective axis of rotation parallel to each other; and the protruding portion has a plurality of crush ribs on both sides of the outer circumferential surface of the protruding portion in the direction in which the two driven gears are aligned, which contact the inner wall of the storage portion.

2. The steering angle sensor according to claim 1, wherein the crush rib abuts against the inner wall of the storage compartment with a length shorter than the length of the protrusion in the direction of insertion of the protrusion into the storage compartment.

3. The steering angle sensor according to claim 2, wherein the length of the crush rib in the insertion direction is shorter than the length of the protruding portion in the insertion direction.

4. The steering angle sensor according to any one of claims 1 to 3, wherein the crush rib extends along the insertion direction of the protrusion into the storage portion and has a tapered portion whose height from the outer surface of the protrusion decreases as it approaches the tip side of the protrusion in the insertion direction.

5. The steering angle sensor according to any one of claims 1 to 4, wherein the driven gear assembly includes a seal member placement portion where a seal member is arranged, the housing has a seal member contact portion on the inlet side of the storage portion in the insertion direction of the protruding portion into the storage portion where the seal member contacts the inner circumferential surface, and the seal member is arranged in the seal member placement portion and contacts both the seal member placement portion and the seal member contact portion at a position on the inlet side of the storage portion in the insertion direction.

6. The steering angle sensor according to any one of claims 1 to 5, wherein the inner wall of the storage portion has a tapered portion in which the distance between the inner wall of the storage portion and the outer surface of the protrusion decreases as it moves from the opening side of the storage portion toward the rear in the direction of insertion of the protrusion into the storage portion, and a flat portion located further rear than the tapered portion in the insertion direction in which the distance between the inner wall of the storage portion and the outer surface of the protrusion remains constant, and the crush rib abuts against the inner wall of the storage portion at the flat portion.

7. The steering angle sensor according to any one of claims 1 to 5, wherein the inner wall of the storage portion has an enlarged diameter portion located on the opening side of the storage portion in the insertion direction of the protrusion into the storage portion and spaced away from the outer surface of the protrusion, and a reduced diameter portion located further back than the enlarged diameter portion in the insertion direction and the distance from the outer surface of the protrusion is smaller than the distance between the enlarged diameter portion and the outer surface of the protrusion, and the crush rib abuts the inner wall of the storage portion at the reduced diameter portion.

8. The steering angle sensor according to any one of claims 1 to 7, wherein the shaft has a first shaft, a second shaft, and a torsion bar connecting the first shaft and the second shaft, and comprises a torque sensor having a stator attached to one of the first shaft and the second shaft, and a magnet attached to the other of the first shaft and the second shaft and positioned inside the stator in the radial direction of the shaft, and the main gear is attached to the stator and attached to the shaft via the stator.

9. The steering angle sensor according to claim 8, wherein the stator has an annular flange portion, the driven gear assembly has a magnetic collecting yoke for the torque sensor arranged on the flange portion of the stator with a space between them, and the protrusion has a plurality of crush ribs on both sides of the outer circumferential surface of the protrusion in the axial direction of the shaft that abut against the inner wall of the housing portion.

Images