Steering device

Abstract

This steering device comprises an input shaft, an output shaft, a cylindrical upper column, a cylindrical lower column, a sensor device, and a dust seal. The dust seal has a first portion attached to the outer peripheral surface of the output shaft and extending in the axial direction, and a second portion having flexibility and extending from the first portion toward the outer peripheral side. As viewed from the axial direction, the upper column overlaps the second portion.

Description

Steering device

[0001] The present disclosure relates to a steering device.

[0002] The steering device described in Patent Document 1 includes an input shaft connected to a steering wheel, an output shaft inserted into the input shaft, an upper column disposed on the outer periphery of the input shaft and rotatably supporting the input shaft, a lower column disposed on the outer periphery of the output shaft, engaged with the upper column, and rotatably supporting the output shaft, a torque sensor provided on the output shaft, and a dust seal attached to the inner periphery of the upper column at a position closer to the steering wheel than the torque sensor. The dust seal includes a mounting portion attached to the inner periphery of the upper column, a vertical wall portion extending inward from the mounting portion, a lip portion provided on the inner periphery of the vertical wall portion and abutting against the output shaft, and a core metal embedded in the mounting portion and the vertical wall portion by, for example, insert molding. The mounting portion, vertical wall portion, and lip portion are formed of resin or rubber, and the core metal is formed of metal. Therefore, the mounting portion and vertical wall portion have high strength due to the core metal.

[0003] JP 2011-251610 A

[0004] In the event of a secondary vehicle collision, the input shaft and upper column move forward of the vehicle when the occupant hits the steering wheel, and the collision energy is absorbed. Here, in Patent Document 1, the front end of the upper column overlaps with the mounting portion and the vertical wall portion when viewed from the axial direction.

[0005] As described above, the mounting portion and the vertical wall portion have high strength due to the core metal. Therefore, if the front end of the upper column hits the mounting portion and the vertical wall portion of the dust seal as the upper column moves toward the front of the vehicle during a secondary collision, the movement of the upper column may be restricted, and the amount of collision energy absorbed may decrease.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a steering device that can absorb a larger amount of collision energy during a secondary collision.

[0007] In order to achieve the above-mentioned object, a steering device of one embodiment of the present invention comprises: an input shaft extending in the axial direction of a central axis and connected to a steering wheel at one side in the axial direction; an output shaft located on the other side of the input shaft in the axial direction, fitted with the input shaft, and movable in the axial direction relative to the input shaft; a cylindrical upper column located on the outer circumferential side of the input shaft and rotatably supporting the input shaft; a cylindrical lower column fitted with the upper column, movable in the axial direction relative to the upper column, and rotatably supporting the output shaft; a sensor device located between the output shaft and the lower column; and a dust seal located on one side of the sensor device in the axial direction and extending annularly along the circumferential direction of the central axis, wherein the dust seal has a first portion attached to the outer circumferential surface of the output shaft and extending in the axial direction, and a flexible second portion extending outward from the first portion, wherein the upper column overlaps with the second portion when viewed in the axial direction.

[0008] As described above, the mounting portion and vertical wall portion of the dust seal described in Patent Document 1 have high strength due to the core metal. Therefore, if the front end of the upper column hits the mounting portion and vertical wall portion of the dust seal when the upper column moves toward the front of the vehicle during a secondary collision, the movement of the upper column may be restricted, and the amount of collision energy absorbed may decrease.

[0009] In contrast, in the present disclosure, when viewed from the axial direction, the upper column overlaps with the flexible second portion. Therefore, when the front end of the upper column hits the second portion of the dust seal as it moves toward the front of the vehicle during a secondary collision, the front end of the upper column tilts the second portion, elastically deforming it. In this state, the front end of the upper column can move toward the front of the vehicle beyond the position of the second portion. Thus, according to the present disclosure, the movement length of the upper column is longer, and the amount of collision energy absorbed is also greater.

[0010] In another aspect of the steering device, the first portion of the dust seal has a reinforcing member.

[0011] According to this, the first section is attached to the outer peripheral surface of the output shaft and extends in the axial direction. Therefore, by providing a reinforcing member in the first section, the attachment strength of the first section to the output shaft is improved. As a result, even if the front end of the upper column hits the second section of the dust seal hard, the entire dust seal is less likely to shift in position in the axial direction, and problems such as the dust seal interfering with the torque sensor are less likely to occur.

[0012] In another aspect of the steering device, one of the outer peripheral surface of the output shaft and the inner peripheral surface of the first portion is provided with a convex portion that protrudes toward the other, and the other is provided with a concave portion that fits into the convex portion.

[0013] This makes it difficult for the dust seal to become misaligned in the axial direction, and reduces the likelihood of problems such as the dust seal interfering with the torque sensor.

[0014] In another aspect of the steering device, an annular key lock collar having a plurality of protrusions is fitted onto the outer peripheral surface of the output shaft, a lock pin that moves radially can be inserted into a groove between the protrusions, an opening through which the lock pin can pass is provided in a portion of the lower column that is radially opposite the key lock collar, and the dust seal is arranged between the sensor device and the opening in the axial direction.

[0015] According to this, if an opening is provided in the lower column, dirt, dust, etc. can easily enter the space between the lower column and the output shaft through the opening. Therefore, by disposing a dust seal between the sensor device and the opening, it is possible to prevent dirt, dust, etc. from adhering to the sensor device.

[0016] According to the present invention, it is possible to provide a steering device that can absorb a larger amount of collision energy in the event of a secondary collision.

[0017] FIG. 1 is a schematic diagram of a steering device according to a first embodiment. FIG. 2 is a cross-sectional view of the steering device according to the first embodiment. FIG. 3 is an enlarged view of a portion of FIG. 2. FIG. 4 is a cross-sectional view showing a state after the upper column has moved axially in FIG. 3. FIG. 5 is a perspective view of a dust seal according to the first embodiment. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view of a portion of a steering device according to a second embodiment. FIG. 8 is a perspective view of a dust seal according to the second embodiment. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 10A is a cross-sectional view of a portion of a steering device according to a third embodiment. FIG. 10B is a cross-sectional view taken along line XB-XB in FIG. 10A. FIG. 11A is a schematic diagram showing the procedure for inserting an output shaft equipped with a dust seal into a lower column according to the third embodiment. FIG. 11B is a schematic diagram showing the procedure for inserting a lower column equipped with a dust seal into an output shaft in a comparative example. Fig. 12 is a schematic diagram showing a procedure for inserting an output shaft with a dust seal and a magnet attached into a magnetizing device in the third embodiment. Fig. 13 is a cross-sectional view of a steering device in a fourth embodiment.

[0018] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following modes for carrying out the invention (hereinafter referred to as embodiments). Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

[0019] First Embodiment First, a first embodiment will be described. Fig. 1 is a schematic diagram of a steering device in the first embodiment.

[0020] 1, the steering device 80 includes, in order of transmission of force applied by the operator, a steering wheel 81, a steering shaft 2, a steering force assist mechanism 83, a universal joint 84, an intermediate shaft 85, and a universal joint 86, which are joined to a pinion shaft 87. In the following description, one axial side of the center axis AX is referred to as the X1 side, and the other axial side is referred to as the X2 side.

[0021] 1 , the steering shaft 2 includes an input shaft 21 and an output shaft 22. One end of the input shaft 21 is connected to a steering wheel 81, and the other end of the input shaft 21 is connected to an output shaft 22. In addition, one end of the output shaft 22 is connected to the input shaft 21, and the other end of the output shaft 22 is connected to a universal joint 84.

[0022] The intermediate shaft 85 connects the universal joint 84 and the universal joint 86. One end of the intermediate shaft 85 is connected to the universal joint 84, and the other end is connected to the universal joint 86. One end of the pinion shaft 87 is connected to the universal joint 86, and the other end of the pinion shaft 87 is connected to a steering gear 88. The rotation of the steering shaft 2 is transmitted to the pinion shaft 87 via the intermediate shaft 85.

[0023] The steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to the pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into linear motion by the rack 88b. The rack 88b is connected to a tie rod 89. The angle of the wheels changes as the rack 88b moves.

[0024] The steering force assist mechanism 83 includes a reduction gear 92 and an electric motor 93. The reduction gear 92 is, for example, a worm reduction gear. Torque generated by the electric motor 93 is transmitted to the worm wheel 62 (see FIG. 2) via a worm inside the reduction gear 92, causing the worm wheel 62 to rotate. The reduction gear 92 increases the torque generated by the electric motor 93 by means of the worm and the worm wheel 62. The reduction gear 92 then applies an assisting steering torque to the output shaft 22. In other words, the steering device 80 is of a column assist type.

[0025] As shown in FIG. 1 , the steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 4, and a vehicle speed sensor 95. The electric motor 93, the torque sensor 4, and the vehicle speed sensor 95 are electrically connected to the ECU 90. The torque sensor 4 outputs the steering torque transmitted to the input shaft 21 to the ECU 90 via CAN (Controller Area Network) communication. The vehicle speed sensor 95 detects the traveling speed (vehicle speed) of the vehicle body on which the steering device 80 is mounted. The vehicle speed sensor 95 is provided on the vehicle body, and outputs the vehicle speed to the ECU 90 via CAN communication.

[0026] The ECU 90 controls the electric motor 93. The ECU 90 acquires signals from the torque sensor 4 and the vehicle speed sensor 95. When the ignition switch 98 is on, the ECU 90 is supplied with power from a power supply device 99 (e.g., an on-board battery). The ECU 90 calculates an auxiliary steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the amount of power supplied to the electric motor 93 based on the auxiliary steering command value. The ECU 90 acquires information on the induced voltage from the electric motor 93 or information output from a resolver or the like provided in the electric motor 93. By the ECU 90 controlling the electric motor 93, the force required to operate the steering wheel 81 is reduced.

[0027] 2 is a cross-sectional view of the steering device according to the first embodiment. As shown in FIG. 2, the steering device 80 includes a steering shaft 2, a steering column 5, a torque sensor (sensor device) 4, and a dust seal 1.

[0028] The steering shaft 2 has an input shaft 21 and an output shaft 22. The steering shaft 2 has a center axis AX. The input shaft 21 has a cylindrical shape. A steering wheel 81 is connected to an end 21a on the X1 side (one side in the axial direction) of the input shaft 21. A portion of the output shaft 22 is spline-fitted to the inner peripheral side of an end 21b on the X2 side (the other side in the axial direction) of the input shaft 21.

[0029] The output shaft 22 is located on the X2 side with respect to the input shaft 21. The output shaft 22 has a first output shaft 221, a second output shaft 222, and a torsion bar 223.

[0030] The first output shaft 221 includes a medium diameter portion 221f, a small diameter portion 221g, and a large diameter portion 221h. The medium diameter portion 221f is the X1 side portion of the first output shaft 221, the small diameter portion 221g is adjacent to the medium diameter portion 221f on the X2 side, and the large diameter portion 221h is adjacent to the small diameter portion 221g on the X2 side. The diameter of the medium diameter portion 221f is larger than the diameter of the small diameter portion 221g, and the diameter of the large diameter portion 221h is larger than the diameter of the medium diameter portion 221f. The medium diameter portion 221f is cylindrical, and the small diameter portion 221g and the large diameter portion 221h are solid. The X1 side end portion 221a of the first output shaft 221 is spline-fitted to the inner peripheral side of end portion 221b. That is, a spline portion 221e is provided on the outer peripheral surface of the end portion 221a, and a spline portion 21c is provided on the inner peripheral surface of the end portion 21b, and the spline portion 221e and the spline portion 21c are spline-fitted together. As a result, the output shaft 22 rotates together with the input shaft 21, and the input shaft 21 is capable of sliding axially relative to the output shaft 22. A radial wall portion 221d is provided at the boundary between the small diameter portion 221g and the large diameter portion 221h. In a cross section including the central axis AX, the outer peripheral surface 221c of the small diameter portion 221g and the radial wall portion 221d are perpendicular to each other. The tip end 21d of the input shaft 21 can abut against the radial wall portion 221d. When the input shaft 21 moves toward the X2 side and the tip end 21d abuts against the radial wall portion 221d, the axial movement of the input shaft 21 and the upper column 51 toward the X2 side is stopped.

[0031] The second output shaft 222 is adjacent to the first output shaft 221 on the X2 side. The second output shaft 222 is connected to the first output shaft 221 via a torsion bar 223. Specifically, an X2-side end 221b of the first output shaft 221 is provided with a recess that recesses toward the X1 side, and the X1-side end of the torsion bar 223 fits into this recess. The X2-side end of the torsion bar 223 is connected to the X2-side end of the second output shaft 222 via a pin 224.

[0032] The steering column 5 has an upper column 51 and a lower column 52. The upper column 51 is cylindrical and is disposed on the outer peripheral side of the input shaft 21. The upper column 51 rotatably supports the input shaft 21 via a bearing 63. The bearing 63 is disposed between the inner peripheral surface of the end of the upper column 51 on the X1 side and the outer peripheral surface of the input shaft 21.

[0033] The lower column 52 is located on the X2 side relative to the upper column 51. A fitting portion 52a is provided at the X1 side end of the lower column 52. The inner circumferential surface of the fitting portion 52a fits into the outer circumferential surface of the upper column 51, and when the upper column 51 moves toward the X2 side, frictional resistance is generated between the inner circumferential surface of the fitting portion 52a and the outer circumferential surface of the upper column 51. This frictional resistance absorbs collision energy during a secondary collision, for example, when an occupant strikes the steering wheel 81 and the upper column 51 moves axially. The lower column 52 has a vehicle body support portion 61 to which the lower column 52 is attached via bolts BL. A vehicle body mounting member 60 is provided at the X1 side end of the lower column 52. A steering device 80 is attached to the vehicle body via the vehicle body mounting member 60 and the vehicle body support portion 61. The lower column 52 rotatably supports the output shaft 22 via bearings 64 and 65. The worm wheel 62 is located between the bearing 64 and the bearing 65 in the axial direction.

[0034] The configuration of the torque sensor (sensor device) 4 will be described with reference to Figures 3 and 4. Figure 3 is an enlarged view of a portion of Figure 2. Figure 4 is a cross-sectional view showing a state after the upper column has moved axially in Figure 3. As shown in Figures 3 and 4, the torque sensor (sensor device) 4 is capable of detecting the torque acting between the first output shaft 221 and the second output shaft 222 by detecting the angle of relative rotation between the first output shaft 221 and the second output shaft 222. The torque sensor 4 is disposed between the output shaft 22 and the lower column 52. A specific description will be given below.

[0035] As shown in FIGS. 3 and 4 , the torque sensor 4 includes a magnet 41 and a stator 42. The magnet 41 is fixed to the large-diameter portion 221h of the first output shaft 221. The stator 42 is fixed to the second output shaft 222. The magnet 41 and the stator 42 are radially opposed to each other. In this manner, the magnet 41 and the stator 42 are separately attached to the first output shaft 221 and the second output shaft 222, respectively. The magnet 41 and the stator 42 are arranged in this positional relationship. When torque is transmitted between the first output shaft 221 and the second output shaft 222 via the torsion bar 223 and the first output shaft 221 and the second output shaft 222 rotate slightly relative to each other, the relative positional relationship between the magnet 41 and the stator 42 changes, and accordingly, the magnetic flux acting from the magnet 41 on the stator 42 changes.

[0036] Next, the configuration of the dust seal will be described with reference to Figures 3, 5, and 6. Figure 5 is a perspective view of the dust seal according to the first embodiment. Figure 6 is a cross-sectional view taken along line VI-VI in Figure 5.

[0037] As shown in Figures 3, 5, and 6, the dust seal 1 extends annularly in the circumferential direction of the central axis AX. The dust seal 1 has a dustproof effect that prevents dirt, dust, and the like from adhering to the torque sensor 4. The dust seal 1 is disposed close to the X1 side of the torque sensor 4. The dust seal 1 includes a first portion 11, a second portion 12, and a reinforcing member 14. The first portion 11 and the second portion 12 are, for example, integrally molded. The first portion 11 and the second portion 12 are, for example, formed of an elastic material such as resin or rubber.

[0038] The first section 11 is attached to the outer circumferential surface of the output shaft 22 and extends in the axial direction. Specifically, the first section 11 is attached to the outer circumferential surface 221i of the large diameter portion 221h of the first output shaft 221. The first section 11 extends from the end 11a to the bent portion 11b.

[0039] The second portion 12 extends radially outward from the bent portion 11b. The bent portion 11b is the end portion of the first portion 11 on the X1 side. A lip portion 12a is provided at the end portion on the radially outward side of the second portion 12. A tip end 12b of the lip portion 12a abuts against the inner circumferential surface of the abutment portion 52c of the lower column 52.

[0040] The dust seal 1 also includes a reinforcing member 14 embedded in the first portion 11 and the second portion 12 by, for example, insert molding. The reinforcing member 14 is, for example, a core metal extending annularly along the circumferential direction of the central axis AX. The core metal is formed of metal. The core metal has higher strength than the first portion 11 and the second portion 12. The reinforcing member 14 has an L-shaped cross section. The reinforcing member 14 includes a cylindrical portion 14a and an annular portion 14b. The cylindrical portion 14a and the annular portion 14b are connected. For example, by insert molding, the cylindrical portion 14a is embedded in the first portion 11, and the annular portion 14b is embedded in the second portion 12. The reinforcing member 14 may not be embedded, but may instead be attached to, for example, the inner circumferential surface of the first portion 11.

[0041] 3 and 6, the portion of the second section 12 that is more radially outward than the annular section 14b of the reinforcing member 14 is a flexible section 12c that has flexibility. That is, when an axial force is applied to the flexible section 12c, it elastically deforms in the axial direction. When viewed from the axial direction, the upper column 51 overlaps with the second section 12. More specifically, when viewed from the axial direction, the upper column 51 overlaps with the flexible section 12c in the second section 12. This will be explained in detail below.

[0042] As shown in FIG. 1 , the distance between the central axis AX and the outer peripheral surface of the upper column 51 is a first distance D1. The distance between the central axis AX and the inner peripheral surface of the upper column 51 is a second distance D2. As shown in FIG. 3 , the distance between the central axis AX and the outer peripheral end of the flexible portion 12c of the dust seal 1 (the tip 12b of the lip portion) is a third distance D3. The distance between the central axis AX and the inner peripheral end of the flexible portion 12c of the dust seal 1 (the outer peripheral end of the annular portion 14b of the reinforcing member 14) is a fourth distance D4. The first distance D1 is smaller than the third distance D3. The second distance D2 is larger than the fourth distance D4. From the above, when viewed in the axial direction, the upper column 51 overlaps with the flexible portion 12c in the second section 12.

[0043] Therefore, as shown in Figure 4, when the upper column 51 moves toward the X2 side, the front end 51a on the X2 side of the upper column 51 comes into contact with the flexible portion 12c of the dust seal 1, causing the flexible portion 12c to elastically deform and bend toward the X2 side, and the upper column 51 can move to a position closer to the X2 side than the dust seal 1.

[0044] As described above, the steering device 80 according to the first embodiment includes the input shaft 21, the output shaft 22, the cylindrical upper column 51, the cylindrical lower column 52, the torque sensor (sensor device) 4, and the dust seal 1. The dust seal 1 has a first section 11 attached to the outer circumferential surface 221i of the first output shaft 221, and a flexible second section 12 extending outward from the first section 11. When viewed in the axial direction, the upper column 51 overlaps with the second section 12.

[0045] As described above, the mounting portion and vertical wall portion of the dust seal described in Patent Document 1 have high rigidity due to the core metal. Therefore, if the front end of the upper column hits the mounting portion and vertical wall portion of the dust seal when the upper column moves toward the front of the vehicle during a secondary collision, the movement of the upper column may be restricted, and the amount of collision energy absorbed may decrease.

[0046] In contrast, in this embodiment, when viewed from the axial direction, the upper column 51 overlaps with the flexible second portion 12. Therefore, when the upper column 51 moves toward the front of the vehicle during a secondary collision, the front end 51 a of the upper column 51 first hits the second portion 12 of the dust seal 1, and the front end 51 a of the upper column 51 tilts and elastically deforms the second portion 12. This allows the front end 51 a of the upper column 51 to move toward the front of the vehicle beyond the position of the second portion 12. In this way, the moving distance of the upper column 51 is longer, and the amount of collision energy absorbed is also greater.

[0047] The first portion 11 of the dust seal 1 has a reinforcing member 14 .

[0048] The first section 11 is attached to the outer peripheral surface of the output shaft 22 and extends in the axial direction. Therefore, by providing the first section 11 with a reinforcing member 14, the attachment strength of the first section 11 to the output shaft 22 is improved. As a result, even if the front end 51 a of the upper column 51 hits hard against the second section 12 of the dust seal 1, the entire dust seal 1 is less likely to shift in position in the axial direction, and problems such as the dust seal 1 interfering with the torque sensor 4 are less likely to occur.

[0049] [Second embodiment] Next, a second embodiment will be described. Fig. 7 is a cross-sectional view of a portion of a steering device according to the second embodiment. Fig. 8 is a perspective view of a dust seal according to the second embodiment. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. A dust seal 1A according to the second embodiment includes a recess 11d. This will be described in detail below.

[0050] As shown in Figures 7 to 9, the dust seal 1A according to the second embodiment includes a first section 11A and a second section 12A. A recess 11d recessed toward the outer periphery is provided on the inner circumferential surface 11c of the first section 11A. A protrusion 221j protruding toward the outer periphery is provided on the outer circumferential surface of the output shaft 22 (specifically, the outer circumferential surface 221i of the first output shaft 221). The protrusion 221j fits into the recess 11d. This allows the first section 11 of the dust seal 1A to be attached to the output shaft 22.

[0051] As described above, in the dust seal 1A of the steering device 80A according to the second embodiment, a convex portion 221j that protrudes radially outward is provided on the outer peripheral surface of the output shaft 22 (the outer peripheral surface 221i of the first output shaft 221), and a concave portion 11d that fits into the convex portion 221j is provided on the inner peripheral surface 11c of the first part 11.

[0052] This makes it difficult for the dust seal 1A to be displaced in the axial direction, and makes it difficult for problems such as the dust seal 1A interfering with the torque sensor 4 to occur.

[0053] In this embodiment, a convex portion 221j is provided on the output shaft 22 and a concave portion 11d is provided on the inner surface 11c of the first portion 11, but conversely, a concave portion may be provided on the output shaft 22 and a convex portion may be provided on the inner surface 11c of the first portion 11.

[0054] [Third Embodiment] Next, a third embodiment will be described. Fig. 10A is a cross-sectional view of a portion of a steering device according to the third embodiment. Fig. 10B is a cross-sectional view taken along line XB-XB in Fig. 10A. Fig. 11A is a schematic diagram showing the procedure for inserting an output shaft equipped with a dust seal into a lower column in the third embodiment. Fig. 11B is a schematic diagram showing the procedure for inserting a lower column equipped with a dust seal into an output shaft in a comparative example. Fig. 12 is a schematic diagram showing the procedure for inserting an output shaft equipped with a dust seal and a magnet into a magnetizing device in the third embodiment. A steering device 80B according to the third embodiment is provided with a key lock collar 3. This will be described in detail below.

[0055] As shown in FIGS. 10A and 10B , a key lock collar 3 is fitted and fixed to the outer peripheral surface 221i of the large diameter portion 221h of the output shaft 22. The key lock collar 3 extends annularly in the circumferential direction of the central axis AX. The outer periphery of the key lock collar 3 is provided with a plurality of convex portions 31 that protrude radially outward. The convex portions 31 are arranged at equal intervals along the circumferential direction on the outer periphery of the key lock collar 3. Grooves 31a are provided between adjacent convex portions 31 in the circumferential direction. An opening 52b is provided in the lower column 52. The opening 52b is located at a portion of the lower column 52 that faces the key lock collar 3 in the radial direction. The opening 52b penetrates the lower column 52 in the radial direction. A lock pin 32 that is movable in the radial direction is provided. The lock pin 32 can move radially inward and be inserted into and fitted into the grooves 31a between the convex portions 31 of the key lock collar 3. The lock pin 32 can pass through the opening 52b. When the lock pin 32 is fitted into the groove 31a of the key lock collar 3, the steering wheel 81 (see FIG. 2) cannot be rotated. This prevents the vehicle from being stolen. Also, as shown in FIG. 10A, in the third embodiment, a dust seal 1 is disposed axially between the torque sensor 4 and the opening 52b.

[0056] The procedure for assembling the steering device 80B according to the third embodiment will be briefly described below. As shown in Figure 11A, first, the key lock collar 3 and the dust seal 1 are fitted to the outer peripheral surface of the output shaft 22. Next, the lower column 52 is placed on the outer peripheral side of the output shaft 22 to which the key lock collar 3 and the dust seal 1 are fitted, and is moved downward (towards X2) in Figure 11A. As a result, the inner peripheral surface of the lower column 52 slides against the tip of the second portion 12 of the dust seal 1 while moving downward, resulting in the state shown in Figure 11A.

[0057] In contrast, as shown in Fig. 11B, the dust seal 1C according to the comparative example is formed with an L-shaped cross section. Specifically, the dust seal 1C includes a cylindrical portion 1Ca and an annular portion 1Cb. The cylindrical portion 1Ca is attached to the inner circumferential surface of the lower column 52 and extends in the axial direction. The annular portion 1Cb extends radially inward from the X1-side end of the cylindrical portion 1Ca. In this way, the dust seal 1C is formed with an L-shaped cross section by the cylindrical portion 1Ca and the annular portion 1Cb.

[0058] Furthermore, in assembling the steering device 80C, first, the output shaft 22 with the key lock collar 3 fitted thereto is placed on the inner periphery of the lower column 52 to which the dust seal 1C is attached. Then, the lower column 52 and dust seal 1C are moved downward (toward X2) in Figure 11B. This causes the annular portion 1Cb of the dust seal 1C to interfere with the side surface 33 of the key lock collar 3, making it difficult to assemble the steering device 80C in the comparative example.

[0059] Next, a brief description will be given of the magnetization process for the magnet 41 provided on the output shaft 22 according to the third embodiment. The magnetizer 100 shown in FIG. 12 has a through-hole 110 extending vertically in FIG. 12 . The magnet 41 is positioned on the X2 side relative to the dust seal 1. The second portion 12 of the dust seal 1 extends radially outward from the X1-side end of the first portion. Therefore, when magnetizing the magnet 41 provided on the output shaft 22, the magnet 41 is first positioned on the lower side (X2 side) of FIG. 12 , and the dust seal 1 is positioned on the upper side (X1 side) of FIG. 12 relative to the magnet 41. Then, the magnet 41 is inserted into the through-hole 110. This allows the second portion 12 of the dust seal 1 to be positioned close to the upper surface 120 of the magnetizer 100 without interfering with the upper surface 120. In this way, the dust seal 1 does not interfere with the magnetization process for the magnet 41.

[0060] As described above, in the steering device 80D according to the third embodiment, the annular key lock collar 3 is fitted onto the outer peripheral surface of the output shaft 22 (the outer peripheral surface 221i of the first output shaft 221). An opening 52b through which the lock pin 32 can pass is provided in a portion of the lower column 52 that faces radially opposite the key lock collar 3. A dust seal 1 is disposed between the torque sensor 4 and the opening 52b in the axial direction.

[0061] If the opening 52b is provided in the lower column 52, dirt, dust, etc. can easily enter the space between the lower column 52 and the output shaft 22 through the opening 52b. Therefore, by disposing the dust seal 1 between the torque sensor 4 and the opening 52b, it is possible to prevent dirt, dust, etc. from adhering to the torque sensor 4.

[0062] [Fourth embodiment] Next, a fourth embodiment will be described. Fig. 13 is a cross-sectional view of a steering device according to the fourth embodiment. A steering device 80D according to the fourth embodiment differs from the steering device 80 according to the first embodiment in that it has a steering shaft 2D. This will be described in detail below.

[0063] In the first embodiment, the steering shaft 2 has an input shaft 21 and an output shaft 22. The input shaft 21 has a cylindrical shape, and the output shaft 22 is solid.

[0064] In contrast, in the fourth embodiment, the steering shaft 2D includes an input shaft 21D and an output shaft 22D. The input shaft 21D is solid, and the output shaft 22D is cylindrical. The X1 side end of the output shaft 22D is inserted into the inner peripheral side of the X2 side end of the input shaft 21D and spline-fitted.

[0065] As described above, in the fourth embodiment, it is also possible to adopt a mode in which the input shaft 21D is solid and the output shaft 22D is cylindrical.

[0066] DESCRIPTION OF SYMBOLS 1, 1A, 1C Dust seal 1Ca Cylindrical portion 1Cb Annular portion 11, 11A First portion 11a End 11b Bent portion 11c Inner peripheral surface 11d Recess 12, 12A Second portion 12a Lip portion 12b Tip 12c Flexible portion 14 Reinforcing member 14a Cylindrical portion 14b Annular portion 2, 2D Steering shaft 21, 21D Input shaft 21a End 21b End 21c Spline portion 21d Tip 22, 22D Output shaft 221 First output shaft 221a End 221b End 221c Outer peripheral surface 221d Radial wall portion 221e Spline portion 221f Medium diameter portion 221g Small diameter portion 221h Large diameter portion 221i Outer circumferential surface 221j Convex portion 222 Second output shaft 223 Torsion bar 224 Pin 3 Key lock collar 31 Convex portion 31a Groove portion 32 Lock pin 33 Side surface 4 Torque sensor (sensor device) 41 Magnet 42 Stator 5 Steering column 51 Upper column 51a Front end 52 Lower column 52a Fitting portion 52b Opening 52c Contact portion 60 Vehicle body mounting member 61 Vehicle body support portion 62 Worm wheel 63, 64, 65 Bearings 80, 80A, 80B, 80C, 80D Steering device 81 Steering wheel 83 Steering force assist mechanism 84 Universal joint 85 Intermediate shaft 86 Universal joint 87 Pinion shaft 88 Steering gear 88a Pinion 88b Rack 89 Tie rod 90 ECU 92 Reduction device 93 Electric motor 95 Vehicle speed sensor 98 Ignition switch 99 Power supply device 100 Magnetizing device 110 Through hole 120 Upper surface AX Central axis BL Bolt

Claims

1. A steering device comprising: an input shaft extending in the axial direction of a central axis and connected to a steering wheel at one side in the axial direction; an output shaft located on the other side of the input shaft in the axial direction, mating with the input shaft and movable in the axial direction relative to the input shaft; a cylindrical upper column located on the outer periphery of the input shaft and rotatably supporting the input shaft; a cylindrical lower column mating with the upper column, movable in the axial direction relative to the upper column and rotatably supporting the output shaft; a sensor device located between the output shaft and the lower column; and a dust seal located on one side of the sensor device in the axial direction and extending annularly along the circumferential direction of the central axis, wherein the dust seal has a first portion attached to the outer periphery of the output shaft and extending in the axial direction, and a flexible second portion extending radially outward from the first portion, and wherein the upper column overlaps with the second portion when viewed in the axial direction.

2. A steering device according to claim 1, wherein the first portion of the dust seal has a reinforcing member.

3. A steering device as set forth in claim 1 or 2, wherein one of the outer peripheral surface of the output shaft and the inner peripheral surface of the first section is provided with a convex portion that protrudes toward the other, and the other is provided with a concave portion that fits into the convex portion.

4. A steering device as described in claim 1 or 2, wherein an annular key lock collar having a plurality of protrusions is fitted onto the outer peripheral surface of the output shaft, a lock pin that moves radially can be inserted into a groove between the protrusions, an opening through which the lock pin can pass is provided in a portion of the lower column that faces radially opposite the key lock collar, and the dust seal is arranged between the sensor device and the opening in the axial direction.

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