sensor

Abstract

The present invention relates to a sensor, comprising: a main drive gear, which is installed on a shaft detected by the sensor so that the main drive gear can rotate integrally with the shaft; at least one driven gear, which is meshed with the main drive gear; a sensor housing (31), which accommodates the main drive gear and the at least one driven gear; a biasing member, which biases the at least one driven gear toward the main drive gear; and a conversion mechanism, which is configured to: when a part of the at least one driven gear contacts a part of the main drive gear when the shaft is inserted into the sensor housing (31), an axial force parallel to the axial direction of the shaft and acting on the at least one driven gear is converted into a force in a direction that separates the at least one driven gear from the main drive gear.

Description

Technical Field

[0001] The present invention relates to sensors. Background Art

[0002] With the recent increase in functionality of vehicles, various systems for improving driving stability, such as vehicle stability control systems and electronically controlled suspension systems, are sometimes installed on vehicles. These systems receive the steering angle of a steering wheel as part of vehicle posture information and control the vehicle based on the posture information to stabilize the posture of the vehicle. Therefore, for example, a rotation angle sensor for detecting the steering angle of a steering wheel is installed in the steering column of the vehicle.

[0003] For example, the rotation angle sensor of Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 11-500828 (JP 11-500828A) includes a main drive gear that rotates with the steering shaft and two driven gears that mesh with the main drive gear. The number of teeth of one driven gear is different from the number of teeth of the other driven gear, and therefore, the rotation angles of the two driven gears caused by the rotation of the main drive gear are different from each other. The rotation angle sensor detects the rotation angles of the two driven gears using sensors corresponding to the two driven gears and calculates the rotation angle of the steering shaft based on the detected rotation angles. Summary of the invention

[0004] The rotation angle sensor of JP 11-500828 A is assembled by inserting a steering shaft on which a main drive gear is mounted into a housing in which two driven gears are supported. At this time, depending on the rotational positions of the main drive gear and the two driven gears, the teeth of the driven gears may interfere with the teeth of the main drive gear in the axial direction of the steering shaft. Such interference may hinder the assembly of the rotation angle sensor.

[0005] The present invention provides a sensor that is smoothly assembled.

[0006] One aspect of the present invention relates to a sensor, which includes: a main drive gear, which is installed on a shaft detected by the sensor so that the main drive gear can rotate integrally with the shaft; at least one driven gear, which is meshed with the main drive gear; a sensor housing, which accommodates the main drive gear and the at least one driven gear, the sensor is configured to detect the rotation angle of the shaft based on the rotation of the at least one driven gear rotating together with the main drive gear, the at least one driven gear is supported in the sensor housing so that the at least one driven gear can rotate and can move in the radial direction of the main drive gear, and the at least one driven gear is meshed with the main drive gear by inserting the shaft on which the main drive gear is installed into the sensor housing; a biasing member, which biases the at least one driven gear toward the main drive gear; and a conversion mechanism, which is configured to: when a portion of the at least one driven gear contacts a portion of the main drive gear when the shaft is inserted into the sensor housing, convert an axial force parallel to the axial direction of the shaft and acting on the at least one driven gear into a force in a direction that moves the at least one driven gear away from the main drive gear.

[0007] When the shaft on which the main drive gear is mounted is inserted into the sensor housing in which the driven gear is supported internally, a part of the driven gear may interfere with a part of the main drive gear in the axial direction of the shaft, depending on the rotational position of the driven gear or the main drive gear. In this case, according to the above configuration, the conversion mechanism converts the axial force acting on the driven gear, which is parallel to the axial direction of the shaft, into a force in the direction in which the driven gear is away from the main drive gear. Therefore, the driven gear moves in the direction away from the main drive gear against the biasing force of the biasing member. Therefore, the shaft can be further pushed in the sensor housing while avoiding interference between a part of the driven gear and a part of the main drive gear. When the shaft is inserted into the sensor housing to a predetermined position, the driven gear moves toward the main drive gear under the action of the biasing force of the biasing member, and therefore, the driven gear meshes with the main drive gear. Therefore, since the operation of inserting the shaft into the sensor housing is not hindered by the interference between a part of the driven gear and a part of the main drive gear, the sensor is smoothly assembled.

[0008] In the above-mentioned sensor, two driven gears can be installed as the at least one driven gear; each of the two driven gears can include a gear portion meshing with the main drive gear and an axis portion supported by the sensor housing; and the biasing member can be a helical torsion spring, which includes a coil portion, a first arm and a second arm, the coil portion is supported in the sensor housing, the first arm biases the axis portion of one of the two driven gears toward the main drive gear, and the second arm biases the axis portion of the other of the two driven gears toward the main drive gear.

[0009] According to such a configuration, the two driven gears are biased toward the main drive gear by the first arm and the second arm of the helical torsion spring. Since only one helical torsion spring is provided, an increase in the number of components can be suppressed.

[0010] In the above-mentioned sensor, the conversion mechanism may be an inclined surface provided in a portion of at least one of i) the main drive gear and ii) each of the at least one driven gear, which portion faces a portion of the other of i) the main drive gear and ii) each of the at least one driven gear in the axial direction of the shaft when the shaft is inserted into the sensor housing. In other words, the inclined surface may be provided in the main drive gear or each of the at least one driven gear, or the inclined surface may be provided in the main drive gear and each of the at least one driven gear.

[0011] According to such a configuration, since the inclined surface is simply provided in at least one of i) the main drive gear and ii) each of the at least one driven gear, the configuration is simplified.

[0012] In the above-mentioned sensor, the conversion mechanism may be an inclined surface provided in a portion of at least one of i) the main drive gear and ii) each of the two driven gears, the portion facing a portion of the other of i) the main drive gear and ii) each of the two driven gears in the axial direction of the shaft when the shaft is inserted into the sensor housing. In other words, the inclined surface may be provided in the main drive gear or each of the two driven gears, or the inclined surface may be provided in the main drive gear and each of the two driven gears.

[0013] According to such a configuration, since the inclined surface is simply provided in at least one of i) the main drive gear and ii) each of the two driven gears, the configuration is simplified.

[0014] In the above-mentioned sensor, a torque sensor configured to detect torque acting on the shaft may be installed in the sensor housing.

[0015] According to such a configuration, not only the rotation angle of the shaft but also the torque acting on the shaft is detected by a single sensor.

[0016] In the above sensor, the shaft may be a pinion shaft meshing with a guide shaft that steers a steering wheel of the vehicle.

[0017] The sensor of the above aspect of the present invention is smoothly assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0019] Figure 1 is a configuration diagram of a steering device equipped with a sensor according to an embodiment;

[0020] Figure 2 is a cross-sectional view of a torque angle sensor according to an embodiment, taken along an axial direction of a pinion shaft;

[0021] Figure 3 It is along Figure 2 A cross-sectional view taken along line III-III in FIG.

[0022] Figure 4 is an exploded cross-sectional view of a torque angle sensor according to an embodiment;

[0023] Figure 5 It is along Figure 2 A cross-sectional view of a main portion taken along line VV in FIG. 1 ; and

[0024] Fig. 6A is a cross-sectional view of a main portion showing that teeth of a main drive gear and teeth of a driven gear interfere with each other in the axial direction during assembly of the torque angle sensor, Figure 6B is a cross-sectional view of a main portion showing that the driven gear has moved in a direction away from the main drive gear, and Figure 6C It is a cross-sectional view of a main part showing the meshing of the teeth of the driven gear and the teeth of the main drive gear. DETAILED DESCRIPTION

[0025] An embodiment in which the sensor is applied to a steering device of a vehicle will be described. Figure 1As shown, the steering device 10 of the vehicle includes a steering shaft 12 connected to a steering wheel 11. A pinion shaft 13 is installed at the end of the steering shaft 12 opposite to the steering wheel 11. A guide shaft 14 extends in a direction crossing the pinion shaft 13, and pinion teeth 13a of the pinion shaft 13 are engaged with rack teeth 14a of the guide shaft 14. A left steering wheel 16 and a right steering wheel 16 are connected to respective ends of the guide shaft 14 via a tie rod 15.

[0026] The steering device 10 includes a motor 21 , a speed reduction mechanism 22 , a pinion shaft 23 , a torque angle sensor (hereinafter referred to as “TAS 24 ”), and a control device 25 as a configuration for generating a steering assist force (assist force).

[0027] The motor 21 is a generation source of the steering assist force, and, for example, a three-phase brushless motor is used as the motor 21. The motor 21 is connected to the pinion shaft 23 via the speed reduction mechanism 22. The pinion teeth 23a of the pinion shaft 23 mesh with the rack teeth 14b of the guide shaft 14. The rotation speed of the motor 21 is reduced by the speed reduction mechanism 22, and the resulting rotational force is transmitted from the pinion shaft 23 to the pinion shaft 13 through the guide shaft 14 as the steering assist force.

[0028] The TAS 24 is mounted on the pinion shaft 13 (specifically, the TAS 24 is provided in a gear box that accommodates the guide shaft 14 and the pinion shaft 13). The TAS 24 includes a torque sensor and a rotation angle sensor that are combined with each other. The TAS 24 detects the torque applied to the pinion shaft 13 by the operation of rotating the steering wheel 11 as the steering torque Th. The TAS 24 also detects the rotation angle θpa of the pinion shaft 13 for multiple rotations exceeding 360° as the steering angle θs.

[0029] The control device 25 receives the steering torque Th and the steering angle θs both detected by the TAS 24. The control device 25 also receives the vehicle speed V detected by the vehicle speed sensor 26 installed in the vehicle. The control device 25 performs assist control for generating a steering assist force (assist force) according to the steering torque Th and the vehicle speed V by controlling the current applied to the motor 21. The control device 25 controls the power supply (supply of power) to the motor 21 based on the steering torque Th detected by the TAS 24 and the vehicle speed V detected by the vehicle speed sensor 26.

[0030] Next, the configuration of the TAS 24 will be described. Figure 2As shown, the TAS 24 has a sensor housing 31. The sensor housing 31 is attached to the gear box 17 that accommodates the guide shaft 14. The sensor housing 31 has an insertion hole 32 and a storage chamber 33. The pinion shaft 13 is inserted into the insertion hole 32. Although not shown in the figure, the pinion shaft 13 includes an input shaft located on the side where the steering shaft 12 is located, an output shaft located on the side where the guide shaft 14 is located, and a torsion bar connecting the input shaft and the output shaft. The storage chamber 33 is in the shape of a box that is open in a direction intersecting the axial direction of the pinion shaft 13. The storage chamber 33 is connected to the insertion hole 32 and is open to the outside of the sensor housing 31. The opening 33a of the storage chamber 33 is closed by a cover 34.

[0031] A torque sensor 41 and a rotation angle sensor 51 are installed inside the sensor housing 31. Although not shown in the figure, the torque sensor 41 includes a permanent magnet, a yoke, a magnetic collecting ring and a magnetic sensor. The permanent magnet is fixed to the input shaft of the pinion shaft 13. The yoke is fixed to the output shaft of the pinion shaft 13 and forms a magnetic circuit according to the magnetic field of the permanent magnet. The magnetic collecting ring is fixed in the sensor housing 31 and induces magnetic flux from the yoke. The magnetic sensor detects the magnetic flux induced by the magnetic collecting ring.

[0032] When the torsion bar of the pinion shaft 13 is twisted and deformed due to the operation of the steering wheel 11, the relative positions of the permanent magnet and the yoke in the rotation direction change accordingly. Therefore, the density of the magnetic flux induced from the permanent magnet through the yoke to the magnetic collecting ring changes accordingly. The magnetic sensor generates an electrical signal according to the magnetic flux density. The control device 25 detects the torque acting on the torsion bar as the steering torque based on the electrical signal generated by the magnetic sensor.

[0033] like Figure 3 As shown, the rotation angle sensor 51 has a main drive gear 52 and two driven gears 53, 54. The main drive gear 52 is mounted on the input shaft of the pinion shaft 13 so that the main drive gear 52 can rotate integrally with the input shaft of the pinion shaft 13 (i.e., together with the input shaft of the pinion shaft 13). The two driven gears 53, 54 are rotatably supported in the accommodation chamber 33 of the sensor housing 31 by a support member 55. The two driven gears 53, 54 mesh with the main drive gear 52. Therefore, when the pinion shaft 13 rotates, the main drive gear 52 also rotates together with the pinion shaft 13, and the two driven gears 53, 54 rotate accordingly. The number of teeth of the driven gear 53 is different from the number of teeth of the driven gear 54. Therefore, when the main drive gear 52 rotates together with the rotation of the pinion shaft 13, the rotation angles of the two driven gears 53 and 54 are different from each other relative to the rotation angle of the main drive gear 52. The permanent magnets 57 , 58 are installed in the driven gears 53 , 54 , respectively, so that the permanent magnets 57 , 58 are rotatable integrally with (ie, together with) the driven gears 53 , 54 , respectively.

[0034] like Figure 2 As shown, a substrate 61 is mounted on the inner bottom surface of the receiving chamber 33 of the sensor housing 31. On the side surface of the substrate 61 located on the side where the driven gears 53 and 54 are located (ie, Figure 2 Two magnetic sensors ( Figure 2 The magnetic sensors 62, 63 face the permanent magnets 57, 58 (only one is shown) in the axial direction of the insertion hole 32 of the sensor housing 31. Figure 2 Only one is shown in the figure). Hall sensors or magnetoresistive (MR) sensors are used as magnetic sensors 62, 63. The magnetic sensors 62, 63 generate electrical signals according to changes in the magnetic field that occur with the rotation of the driven gears 53, 54. The control device 25 detects the rotation angle θpa of the pinion shaft 13 as the steering angle θs based on the electrical signals generated by the magnetic sensors 62, 63. The magnetic sensor of the torque sensor 41 is also mounted on the substrate 61.

[0035] Next, the process of assembling TAS will be described. Figure 4 As shown, when the TAS 24 is attached to the gearbox 17, the subassembly (unit) of the TAS 24 is assembled first. The driven gears 53, 54, the base plate 61, and the magnetic collecting ring of the torque sensor 41 are installed in the sensor housing 31 so that these components can be handled together as a subassembly. The main drive gear 52 is attached to the input shaft of the pinion shaft 13. The yoke of the torque sensor 41 is attached to the output shaft of the pinion shaft 13. In this state, the distal end of the pinion shaft 13 is inserted into the subassembly of the TAS 24.

[0036] When the distal end of the pinion shaft 13 is inserted into the subassembly of the TAS 24, the driven gears 53, 54 are closer to the main drive gear 52 in the axial direction of the pinion shaft 13. Finally, the bottom portion 31a of the sensor housing 31 is fitted in the attachment hole 17a of the gear box 17, and the stepped portion 31b formed in the outer peripheral edge portion of the bottom portion 31a of the sensor housing 31 contacts the outer peripheral edge portion defining the attachment hole 17a of the gear box 17. At this time, the teeth of the driven gears 53, 54 are meshed with the teeth of the main drive gear 52. In this state, the bolts are inserted into the fastening portion of the sensor housing 31 and fastened to the gear box 17 to fix the subassembly of the TAS 24 to the gear box 17. The assembly of the TAS 24 is thereby completed.

[0037] The following may occur when assembling the TAS 24. When the pinion shaft 13 is inserted into the subassembly of the TAS 24, the teeth of the two driven gears 53, 54 may interfere with the teeth of the main drive gear 52 in the axial direction of the pinion shaft 13, depending on the rotational positions of the main drive gear 52 and the driven gears 53, 54.

[0038] Therefore, in the present embodiment, the following configuration is adopted as a support structure for supporting the driven gears 53, 54 in the sensor housing 31. Figure 5 As shown in FIG. 1 , the driven gear 53 includes a gear portion 71 in the shape of a circular plate and a magnet holding portion 72 in the shape of a cylindrical column. The outer diameter of the magnet holding portion 72 is smaller than the outer diameter of the gear portion 71. The magnet holding portion 72 is located at the center of the side surface of the gear portion 71. The side surface of the gear portion 71 is located on the side where the substrate 61 is located (that is, the side surface is located at Figure 5 Observer side in). The driven gear 53 has a plurality of teeth 71a arranged on the outer peripheral surface of the gear portion 71. The driven gear 53 also has a cylindrical retaining hole 72a arranged in the side surface of the magnet retaining portion 72. The side surface of the magnet retaining portion 72 is located on the side where the substrate 61 is located. The permanent magnet 57 is fitted in the retaining hole 72a. Like the driven gear 53, the driven gear 54 has a gear portion 73 and a magnet retaining portion 74. The driven gear 54 has a plurality of teeth 73a arranged on the outer peripheral surface of the gear portion 73. The driven gear 54 also has a retaining hole 74a arranged in the side surface of the magnet retaining portion 74. The side surface of the magnet retaining portion 74 is located on the side where the substrate 61 is located. The permanent magnet 58 is fitted in the retaining hole 74a.

[0039] like Figure 2 As shown, an inclined surface 71b is formed on the end portion of each tooth 71a of the driven gear 53 on the side where the base plate 61 is located. Figure 2 In the view shown, the inclined surface 71b of each tooth 71a is inclined so that the radial distance between the inclined surface 71b and the center of the driven gear 53 decreases in the direction toward the base plate 61. The driven gear 54 has a configuration similar to that of the driven gear 53. That is, as shown by Figure 2 As shown in the reference numerals in parentheses, an inclined surface 73b is formed on the end portion of each tooth 73a of the driven gear 54 located on the side where the base plate 61 is located. Figure 2 In the view shown, the inclined surface 73b of each tooth 73a is inclined so that the radial distance between the inclined surface 73b and the center of the driven gear 54 decreases in the direction toward the base plate 61. At the end ( Figure 2 An inclined surface 52b is formed on the upper end portion of each tooth 52a. Figure 2 In the illustrated view, the inclined surface 52b of each tooth 52a is inclined so that the radial distance between the inclined surface 52b and the center of the main drive gear 52 decreases in a direction toward the side opposite to the gear box 17 (ie, a direction away from the gear box 17).

[0040] like Figure 5 As shown, the driven gears 53, 54 are rotatably supported in the sensor housing 31 (i.e., in the accommodating chamber 33) by a supporting member 55 having a rectangular plate shape. The supporting member 55 is installed in the accommodating chamber 33 in a posture such that the long side surface of the supporting member 55 extends along the tangent line of the main drive gear 52. The supporting member 55 has two supporting holes 81, 82. The supporting holes 81, 82 are formed in two corner portions 55d, 55e of the supporting member 55, at which the two short side surfaces 55a, 55b ( Figure 5 The upper surface and the lower surface in the middle) and the long side surface 55c of the support member 55 located on the side where the main drive gear 52 is located (ie, Figure 5 The support holes 81, 82 are long holes extending in the radial direction of the main drive gear 52. The support holes 81, 82 are formed so that the distance between the support holes 81, 82 increases in the direction away from the main drive gear 52.

[0041] like Figure 2 As shown, the magnet holding portions 72, 74 of the driven gears 53, 54 are inserted into the support holes 81, 82. The magnet holding portions 72, 74 of the driven gears 53, 54 are inserted from the side of the support member 55 opposite to the base plate 61 (i.e., the magnet holding portions 72, 74 are inserted from the side of the support member 55 opposite to the base plate 61). Figure 2 61), rather than being inserted into the support holes 81, 82 of the support member 55 from the side where the base plate 61 is provided. When the gear portions 71, 73 of the driven gears 53, 54 are aligned with the side surface of the support member 55 opposite to the base plate 61 (i.e., Figure 2 When the magnet holding portions 72 and 74 are in contact with the upper surface of the support member 55 in the substrate 61, the movement of the driven gears 53 and 54 toward the substrate 61 is restricted. Therefore, the distal ends of the magnet holding portions 72 and 74 (the ends of the magnet holding portions 72 and 74 opposite to the gear portions 71 and 73) are kept facing the magnetic sensors 62 and 63 mounted on the substrate 61.

[0042] The driven gears 53, 54 can slide and rotate relative to the support member 55 via the gear portions 71, 73 (i.e., the driven gears 53, 54 are slidable and rotatable). The driven gears 53, 54 can move along the support holes 81, 82, respectively (i.e., the driven gears 53, 54 are movable). Each of the driven gears 53, 54 moves between a first position and a second position. The first position refers to a position where the magnet holding portions 72, 74 are respectively engaged with the first ends of the support holes 81, 82 (the ends closer to the main drive gear 52). The second position refers to a position where the magnet holding portions 72, 74 are respectively engaged with the second ends of the support holes 81, 82 (the ends farther from the main drive gear 52).

[0043] The plate-shaped stopper 83 is provided on the support member 55 from the side of the support member 55 opposite to the base plate 61. The stopper 83 covers the side surface ( Figure 2 When the gear portions 71, 73 contact the stopper 83, the movement of the driven gears 53, 54 toward the side opposite to the base plate 61 is restricted. The driven gears 53, 54 can slide and rotate relative to the stopper 83 via the gear portions 71, 73.

[0044] like Figure 3 As shown, on the side surface of the support member 55 opposite to the substrate 61 (the side of the support member 55 located at Figure 3 A support portion 84 having a cylindrical shape is provided on the side surface of the support member 55 (the side surface on the observer's side). The support portion 84 is located between the two support holes 81 and 82 in the long side direction of the support member 55. A helical torsion spring 85 is attached to the support portion 84.

[0045] like Figure 5 As shown, the helical torsion spring 85 includes a coil portion 85a, a first arm 85b and a second arm 85c. The support portion 84 is inserted into the coil portion 85a. The first arm 85b is engaged with the portion of the magnet holding portion 72 of the driven gear 53 opposite to the main drive gear 52. The second arm 85c is engaged with the portion of the magnet holding portion 74 of the driven gear 54 opposite to the main drive gear 52. Each of the driven gears 53 and 54 is always biased toward the main drive gear 52 by the elastic force of the helical torsion spring 85. When the magnet holding portions 72 and 74 are engaged with the first end portions (the ends closer to the main drive gear 52) of the support holes 81 and 82, the movement of the driven gears 53 and 54 toward the main drive gear 52 is restricted.

[0046] Next, the function of the support structure for the driven gears 53, 54 will be described. When the pinion shaft 13 is inserted into the subassembly of the TAS 24, when the teeth 52a of the main drive gear 52 are located at positions corresponding to the tooth grooves (spaces (grooves) between the teeth) of the driven gears 53, 54 in the rotational direction of the main drive gear 52 and the driven gears 53, 54, the teeth 52a of the main drive gear 52 smoothly enter the tooth grooves of the driven gears 53, 54 in the axial direction of the pinion shaft 13. In this case, the teeth 52a of the main drive gear 52 mesh with the teeth 71a, 73a of the driven gears 53, 54.

[0047] On the other hand, when the pinion shaft 13 is inserted into the subassembly of the TAS 24, the following events occur when the teeth 52a of the main drive gear 52 are not located at positions corresponding to the tooth grooves of the driven gears 53 and 54 in the rotation direction of the main drive gear 52 and the driven gears 53 and 54.

[0048] like Fig. 6A As shown, as the pinion shaft 13 is inserted into the subassembly of the TAS 24, the teeth 71a, 73a of the driven gears 53, 54 get closer and closer to the teeth 52a of the main drive gear 52. The inclined surfaces 71b, 73b of the teeth 71a, 73a of the driven gears 53, 54 eventually contact the inclined surfaces 52b of the teeth 52a of the main drive gear 52 in the axial direction of the pinion shaft 13.

[0049] like Figure 6B As shown, when the pinion shaft is further pushed in the subassembly of the TAS 24, the force acting on the driven gears 53, 54 in the axial direction of the pinion shaft 13 (the force trying to move the subassembly of the TAS along the pinion shaft 13) is converted into a force in the direction of moving the driven gears 53, 54 away from the main drive gear 52 due to the engagement between the inclined surfaces 71b, 73b of the teeth 71a, 73a and the inclined surface 52b of the teeth 52a. This is because the pinion shaft 13 and the main drive gear 52 supported by the gear case 17 cannot move in the radial direction. Therefore, the inclined surfaces 71b, 73b of the teeth 71a, 73a are guided in the side direction relative to the main drive gear 52 by the inclined surface 52b of the teeth 52a, and the driven gears 53, 54 move in the direction away from the main drive gear 52 against the elastic force of the helical torsion spring 85.

[0050] After the driven gears 53, 54 move in a direction away from the main drive gear 52 to a position where the inclined surfaces 71b, 73b of the driven gears 53, 54 are disengaged from the inclined surface 52b of the main drive gear 52, as the pinion shaft 13 is further inserted into the subassembly of the TAS 24, the driven gears 53, 54 move in the direction in which the subassembly of the TAS 24 moves relative to the pinion shaft 13 ( Figure 6BThe driven gears 53, 54 are relatively moved (in the downward direction). The driven gears 53, 54 are eventually relatively moved to a position where the teeth 71a, 73a of the driven gears 53, 54 are located at the same position as the position where the teeth 52a of the main drive gear 52 are located in the radial direction, or to a position where the teeth 71a, 73a of the driven gears 53, 54 face the teeth 52a of the main drive gear 52 in the radial direction. Even during this movement, the driven gears 53, 54 are biased toward the main drive gear 52 by the elastic force of the helical torsion spring 85. Therefore, in a case where the teeth 71a, 73a of the driven gears 53, 54 are not located at a position corresponding to the tooth grooves of the main drive gear 52, the teeth 71a, 73a of the driven gears 53, 54 slide relative to the teeth 52a of the main drive gear 52 (contact the teeth 52a of the main drive gear 52). When the rotational position of the driven gears 53, 54 changes during this process and the teeth 71a, 73a of the driven gears 53, 54 are located at positions corresponding to the tooth grooves of the main drive gear 52, the driven gears 53, 54 move toward the main drive gear 52 under the action of the elastic force of the helical torsion spring 85.

[0051] like Figure 6C As shown, the teeth 71a, 73a of the driven gears 53, 54 thus enter the tooth grooves of the main drive gear 52 in the radial direction, and therefore, the teeth 71a, 73a of the driven gears 53, 54 mesh with the teeth 52a of the main drive gear 52 in the rotational direction.

[0052] As described above, even in a case where the teeth of the driven gears 53, 54 interfere with the teeth of the main drive gear 52 in the axial direction of the pinion shaft 13 when the pinion shaft 13 is inserted into the subassembly of the TAS 24, the subassembly of the TAS 24 can be attached to the gear case 17 in an appropriate manner by simply inserting the pinion shaft 13 into the subassembly of the TAS 24, that is, so that the driven gears 53, 54 mesh with the main drive gear 52. When the pinion shaft 13 is inserted into the subassembly of the TAS 24, it is not necessary to perform, for example, adjustment of the rotational position of the driven gears 53, 54.

[0053] The effects of the present embodiment will be described. According to the present embodiment, the following effects can be obtained. (1) When the teeth of the driven gears 53, 54 interfere with the teeth of the main drive gear 52 in the axial direction of the pinion shaft 13 when the pinion shaft 13 is inserted into the subassembly of the TAS 24, the driven gears 53, 54 move in a direction away from the main drive gear 52 due to the engagement between the inclined surfaces 71b, 73b of the driven gears 53, 54 and the inclined surface 52b of the main drive gear 52. With such a configuration, the pinion shaft 13 can be further pushed in the subassembly of the TAS 24 while avoiding damage to the teeth 52a of the main drive gear 52 or the teeth 71a, 73a of the driven gears 53, 54. When the pinion shaft 13 is inserted into the subassembly of the TAS 24 to such an extent that the teeth 71a, 73a of the driven gears 53, 54 are located at positions corresponding to the tooth grooves (spaces between the teeth 52a) of the main drive gear 52, the driven gears 53, 54 move toward the main drive gear 52 under the elastic force of the helical torsion spring 85. Therefore, the teeth 71a, 73a of the driven gears 53, 54 mesh with the teeth 52a of the main drive gear 52. Since the assembly of the TAS 24 (the operation of inserting the pinion shaft 13 into the subassembly of the TAS 24) is not hindered by the interference between the teeth of the driven gears 53, 54 and the teeth of the main drive gear 52, the TAS 24 is smoothly assembled.

[0054] (2) When the driven gears 53, 54 interfere with the main drive gear 52 in the axial direction of the pinion shaft 13 during assembly of the TAS 24, the force in the axial direction of the pinion shaft 13 (axial force parallel to the axial direction of the pinion shaft 13) acting on the driven gears 53, 54 is converted into a force in a direction that moves the driven gears 53, 54 away from the main drive gear 52 due to the engagement between the inclined surfaces 71b, 73b of the driven gears 53, 54 and the inclined surface 52b of the main drive gear 52. Since the inclined surfaces 71b, 73b are simply formed in the driven gears 53, 54, and the inclined surface 52b is simply formed in the main drive gear 52, the configurations of the driven gears 53, 54 and the main drive gear 52 are simplified, and thus the configuration of the TAS 24 is simplified.

[0055] (3) The two driven gears 53, 54 are always biased toward the main drive gear 52 by the first arm 85b and the second arm 85c of the helical torsion spring 85. Since only one helical torsion spring 85 is provided, the increase in the number of components of the TAS 24 is restricted.

[0056] (4) The torque sensor 41 and the rotation angle sensor 51 are installed in the sensor housing 31. Therefore, not only the rotation angle of the pinion shaft 13 but also the torque acting on the pinion shaft 13 can be detected by a single sensor (TAS 24).

[0057] (5) The rotation angle sensor 51 of the TAS 24 detects the rotation angle of the main drive gear 52 by detecting the rotation of the two driven gears 53, 54 meshing with the main drive gear 52. Accordingly, especially when the main drive gear 52 starts to rotate or when the rotation direction of the main drive gear 52 is reversed, the looseness caused by the backlash at two positions, namely, the backlash between the main drive gear 52 and the driven gear 53 and the backlash between the main drive gear 52 and the driven gear 54, may affect the calculation accuracy of the rotation angle of the main drive gear 52. In this regard, according to the present embodiment, in the assembled TAS 24, the driven gears 53, 54 are kept pressed against the main drive gear 52 under the elastic force of the helical torsion spring 85. Therefore, the backlash between the teeth 71a, 73a of the driven gears 53, 54 and the teeth 52a of the main drive gear 52 is further reduced. Therefore, since the looseness caused by the backlash is reduced, the calculation accuracy of the rotation angle of the main drive gear 52 is improved.

[0058] The present embodiment may be modified as follows. The main drive gear 52 may not have the inclined surface 52b, or the driven gears 53, 54 may not have the inclined surfaces 71b, 73b. At least one of the main drive gear 52 and the driven gears 53, 54 needs to have an inclined surface. Also in this configuration, when the teeth 71a, 73a of the driven gears 53, 54 interfere with the teeth 52a of the main drive gear 52 in the axial direction of the pinion shaft 13 during assembly of the TAS 24, the force acting on the driven gears 53, 54 in the axial direction of the pinion shaft 13 can be converted into a force in a direction that moves the driven gears 53, 54 away from the main drive gear 52.

[0059] The main drive gear 52 may have an arcuate curved surface instead of the inclined surface 52b. The driven gears 53, 54 may have an arcuate curved surface instead of the inclined surfaces 71b, 73b. Also in this configuration, when the teeth 71a, 73a of the driven gears 53, 54 interfere with the teeth 52a of the main drive gear 52 in the axial direction of the pinion shaft 13 during assembly of the TAS 24, the force acting on the driven gears 53, 54 in the axial direction of the pinion shaft 13 can be converted into a force in a direction that moves the driven gears 53, 54 away from the main drive gear 52.

[0060] In the above embodiment, the TAS 24 is described as an example of the sensor. However, the sensor may be a simple rotation angle sensor 51, that is, the TAS 24 without the torque sensor 41. The simple rotation angle sensor 51 can solve problems similar to those solved by the TAS 24.

[0061] A configuration having a single driven gear 53 or 54 may be used for the TAS 24 or a simple rotation angle sensor. A configuration having three or more driven gears may be used for the TAS 24 or a simple rotation angle sensor.

[0062] In the above embodiment, the device on which the TAS 24 or the simple rotation angle sensor is installed is a steering device of a vehicle. However, the present invention can be applied to other vehicle-mounted devices having an axis (rotation axis). The TAS 24 or the simple rotation angle sensor is not limited to the TAS 24 installed in a vehicle or the simple rotation angle sensor installed in a vehicle.

Claims

1. A sensor, characterized in that include: a main drive gear mounted on a shaft detected by the sensor so that the main drive gear can rotate integrally with the shaft; at least one driven gear meshing with the main drive gear; a sensor housing (31) accommodating the main drive gear and the at least one driven gear, the sensor being configured to detect a rotation angle of the shaft based on rotation of the at least one driven gear rotating together with the main drive gear, the at least one driven gear being supported in the sensor housing (31) so that the at least one driven gear can rotate and can move in a radial direction of the main drive gear, and the at least one driven gear is meshed with the main drive gear by inserting the shaft on which the main drive gear is mounted into the sensor housing (31); a biasing member that biases the at least one driven gear toward the main drive gear; as well as A conversion mechanism, the conversion mechanism being configured to convert an axial force parallel to the axial direction of the shaft and acting on the at least one driven gear into a force in a direction causing the at least one driven gear to move away from the main drive gear when a portion of the at least one driven gear contacts a portion of the main drive gear when the shaft is inserted into the sensor housing (31), Two driven gears are installed as the at least one driven gear; Each of the two driven gears includes a gear portion meshing with the main drive gear and a shaft portion supported by the sensor housing (31); and The biasing member is a helical torsion spring (85), the helical torsion spring (85) including a coil portion (85a) supported in the sensor housing (31), a first arm (85b) biasing the shaft portion of one of the two driven gears toward the main drive gear, and a second arm (85c) biasing the shaft portion of the other of the two driven gears toward the main drive gear, The conversion mechanism is an inclined surface (71b, 73b, 52b) arranged in a portion of each of the at least one driven gear and at least one of the main drive gears, facing each of the at least one driven gear and the other of the main drive gears in the axial direction of the shaft when the shaft is inserted into the sensor housing (31).

2. The sensor according to claim 1, characterized in that A torque sensor (41) configured to detect torque acting on the shaft is installed in the sensor housing (31).

3. The sensor according to claim 1 or 2, characterized in that: The shaft is a pinion shaft (13) meshing with a guide shaft for steering the steering wheels of the vehicle.

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