Steering device

Abstract

In the present invention, a dust seal has a first portion attached to the inner peripheral surface of a lower column and extending in the axial direction, a second portion extending toward the inner peripheral side from a portion of the first portion on the other side in the axial direction, and a third portion extending toward one side in the axial direction from an inner-peripheral-side portion of the second portion. An upper column is positioned between the first portion and the third portion in the radial direction of the center axis.

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, fitted 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 on the steering wheel side of the torque sensor. The dust seal radially seals the gap between the output shaft and the upper column.

[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 strikes the steering wheel, absorbing the collision energy. In Patent Document 1, the front end of the upper column overlaps with the dust seal when viewed axially.

[0005] Therefore, when the upper column moves toward the front of the vehicle during a secondary collision, the front end of the upper column may come into contact with the dust seal, restricting the movement of the upper column and reducing the amount of collision energy absorbed.

[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 object, a steering device according to one aspect of the present invention includes 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 periphery 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 sensor device for detecting the sensor. and a dust seal that is arranged on one side in the axial direction with respect to the device and extends annularly along the circumferential direction of the central axis, the dust seal having a first portion attached to the inner peripheral surface of the lower column and extending in the axial direction, a second portion that extends inward from a portion of the first portion on the other side in the axial direction and has a first end that is an end on one side in the axial direction, and a third portion that is provided on the inner peripheral side of the second portion and has a second end that is an end on one side in the axial direction, the second end being located on one side of the first end in the axial direction, and the upper column being located between the first portion and the third portion in the radial direction of the central axis.

[0008] As described above, in Patent Document 1, the front end of the upper column overlaps with the dust seal when viewed from the axial direction. Therefore, when the upper column moves toward the front of the vehicle during a secondary collision, the front end of the upper column may come into contact with the dust seal, restricting the movement of the upper column and potentially reducing the amount of collision energy absorbed.

[0009] In contrast, in the present disclosure, the dust seal has a U-shaped cross-sectional shape that is convex toward the front of the vehicle, formed by the first portion, the second portion, and the third portion. The upper column is located between the first portion and the third portion in the radial direction. Furthermore, the output shaft is capable of axial movement relative to the input shaft. Therefore, when the upper column moves toward the front of the vehicle during a secondary collision, the tip of the upper column is able to pass between the first portion and the third portion and move to the second portion without hitting the first portion and the third portion. Thus, according to the present disclosure, the amount of axial movement of the upper column can be increased during a secondary collision, thereby increasing the amount of collision energy absorbed.

[0010] In another aspect of the steering device, the third portion of the dust seal extends from an inner peripheral portion of the second portion toward one side in the axial direction, thereby allowing the axial length of the third portion to be set longer, thereby improving the sealing performance of the dust seal.

[0011] In another aspect of the steering device, the dust seal has a reinforcing member, which allows the dust seal to be attached to the lower column more firmly.

[0012] In another aspect of the steering device, the first portion of the dust seal has a convex portion that protrudes toward the outer periphery, and a concave portion that fits into the convex portion is provided on the inner circumferential surface of the lower column. This makes it possible to suppress axial positional deviation of the dust seal with respect to the lower column after the dust seal is assembled to the lower column.

[0013] In another aspect of the steering device, an annular key lock collar is fitted to the outer circumferential surface of the output shaft, and the third portion abuts against the key lock collar. In this way, the key lock collar also serves to protect the torque sensor from dust, and therefore, for example, the length of the third portion of the dust seal can be set short.

[0014] In another aspect of the steering device, an annular key lock collar is fitted to the outer peripheral surface of the output shaft, a first annular member is fitted to the outer peripheral surface of the output shaft at a position between the key lock collar and the dust seal in the axial direction, and the third portion abuts against the first annular member. In this way, the first annular member also provides dust protection for the torque sensor, so that the length of the third portion can be set shorter, for example.

[0015] In another aspect of the steering device, a second annular member is fitted to the outer peripheral surface of the output shaft, and the third portion of the dust seal has an inclined portion extending from an inner portion of the second portion to the inner peripheral side and to one side in the axial direction, and a lip portion provided on the inner peripheral side of the inclined portion, and the lip portion abuts against the outer peripheral surface of the second annular member.

[0016] According to this, the third section has an inclined portion that extends inward from an inner peripheral portion of the second section and toward one side in the axial direction. Therefore, during a secondary collision, the tip of the upper column can move toward the other side in the axial direction, passing between the first section and the third section and moving to the vicinity of the second section. In this way, during a secondary collision, the amount of axial movement of the upper column can be increased, thereby increasing the amount of collision energy absorbed. Furthermore, the second annular member is fitted onto the outer periphery of the first output shaft, and the lip portion abuts against the outer periphery of the second annular member. Therefore, the length of the lip portion can be set shorter than in an embodiment in which the second annular member is not provided.

[0017] In another aspect of the steering device, the second annular member is made of metal, a first annular resin ring is fitted to the outer periphery of the second annular member, the outer periphery of the first resin ring is a cylindrical surface extending in a direction around the central axis, and the lip portion abuts against the cylindrical surface of the first resin ring.

[0018] The second annular member is made of metal and rotates integrally with the output shaft. The dust seal does not rotate and has a lip portion. Therefore, if the lip portion abuts against the second annular member, the relative rotation between the lip portion and the second annular member may cause abnormal noise. Therefore, a first resin ring is fitted onto the outer periphery of the second annular member so that the lip portion abuts against the first resin ring. This reduces the sliding resistance between the lip portion and the first resin ring compared to the sliding resistance between the lip portion and the second annular member, thereby suppressing abnormal noise when the output shaft is rotated.

[0019] In another aspect of the steering device, a second annular resin ring is fitted to the outer periphery of the second annular member, and in a cross section including the central axis, the outer periphery of the second resin ring is provided with a recessed groove that is recessed toward the inner periphery and is capable of storing grease, and the lip portion abuts against the outer periphery of the second resin ring.

[0020] The lip portion and the second resin ring rotate relative to each other, causing the tip of the lip portion to slide against the outer circumferential surface of the second resin ring. Grease accumulates in the groove, reducing the sliding resistance between the lip portion and the second resin ring and suppressing noise.

[0021] 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.

[0022] 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 input shaft has moved axially in FIG. 3. FIG. 5 is a cross-sectional view of a portion of a steering device according to a second embodiment. FIG. 6A is a cross-sectional view of a portion of a steering device according to a third embodiment. FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A. FIG. 7 is a cross-sectional view showing a state after the input shaft has moved axially in FIG. 6A. FIG. 8 is a schematic diagram showing a procedure for inserting a lower column equipped with a dust seal onto an output shaft in the third embodiment. FIG. 9 is a cross-sectional view of a portion of a steering device according to a fourth embodiment. FIG. 10 is a cross-sectional view of a portion of a steering device according to a fifth embodiment. FIG. 11 is a cross-sectional view of a portion of a steering device according to a sixth embodiment. FIG. 12 is a cross-sectional view showing a state after the input shaft has moved axially in FIG. 11. FIG. 13A is an exploded perspective view of a steering device according to a sixth embodiment. FIG. 13B is a perspective view of the steering device according to the sixth embodiment after assembly has been completed. Fig. 14 is a cross-sectional view of a part of a steering device according to a seventh embodiment, Fig. 15 is a cross-sectional view of a part of a steering device according to an eighth embodiment, and Fig. 16 is a cross-sectional view of a steering device according to a ninth embodiment.

[0023] 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.

[0024] First Embodiment First, a first embodiment will be described. Fig. 1 is a schematic diagram of a steering device in the first embodiment.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 an attachment portion 52c. A dust seal 1 is attached to the inner circumferential surface of the attachment portion 52c. 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 attachment 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 attachment member 60 and the vehicle body support portion 61. The lower column 52 rotatably supports the output shaft 22 via bearings 64 and 65. A worm wheel 62 is located between the bearings 64 and 65 in the axial direction.

[0039] Next, the configurations of the dust seal 1 and 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 input shaft in Figure 3 has moved in the axial direction.

[0040] As shown in FIG. 3 , 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. As shown in FIG. 3 , 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 face each other in the radial direction. In this way, the magnet 41 and the stator 42 are separately attached to the first output shaft 221 and the second output shaft 222, respectively. By arranging the magnet 41 and the stator 42 in this positional relationship, torque is transmitted between the first output shaft 221 and the second output shaft 222 via the torsion bar 223, and when 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 the magnetic flux acting from the magnet 41 to the stator 42 changes.

[0041] As shown in FIG. 3 , the dust seal 1 extends annularly along 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 13, a third portion 12, and a reinforcing member 14. The first portion 11, the second portion 13, and the third portion 12 form the dust seal 1 in a cross section including the central axis AX in a U-shape that is convex toward the X2 side. The first portion 11, the second portion 13, and the third portion 12 are, for example, integrally molded. The first portion 11, the second portion 13, and the third portion 12 are, for example, formed of an elastic material such as resin or rubber.

[0042] The first portion 11 is attached to the inner circumferential surface of the mounting portion 52c of the lower column 52 and extends in the axial direction. Specifically, the first portion 11 extends from end 11a to end 11b. The second portion 13 extends from an X2-side portion of the first portion 11 toward the inner circumferential side. Specifically, the second portion 13 extends from end 11b to the bent portion 12a. The second portion 13 extends in a radial direction perpendicular to the central axis AX. The second portion 13 has a first end 13a, which is an end on the X1 side (one side in the axial direction). The first end 13a extends in a direction perpendicular to the central axis AX. In other words, the first end 13a is the X1-side side surface of the second portion 13. The third portion 12 extends from an inner circumferential side portion of the second portion 13 toward the X1 side. Specifically, the third portion 12 bends at a bent portion 12a and extends to its tip. The third portion 12 extends obliquely with respect to the central axis AX, specifically, extending inward toward the X1 side. The third portion 12 has a lip portion 12c that abuts against the outer circumferential surface of the large diameter portion 221h of the output shaft 22. The inner circumferential tip of the lip portion 12c is an end 12b, which abuts against the outer circumferential surface of the large diameter portion 221h. The outer circumferential tip of the lip portion 12c is a second end 12d, which is the end of the third portion 12 on the X1 side (one side in the axial direction). Here, the second end 12d is located closer to the X1 side than the first end 13a.

[0043] The dust seal 1 also includes a reinforcing member 14 embedded in the first portion 11 and the second portion 13. The reinforcing member 14 is, for example, a core bar extending annularly in the circumferential direction of the central axis AX. 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. The cylindrical portion 14a is embedded in the first portion 11. The annular portion 14b is embedded in the second portion 13. The reinforcing member 14 may not be embedded, but may be attached to the inner circumferential surface of the first portion 11, for example.

[0044] As shown in FIG. 2 , the distance between the center axis AX and the outer peripheral surface of the upper column 51 is a first distance D1. The distance between the center axis AX and the inner peripheral surface of the first portion 11 of the dust seal 1 is a second distance D2. The first distance D1 is smaller than the second distance D2. The distance between the center axis AX and the inner peripheral surface of the upper column 51 is a third distance D3. The distance between the center axis AX and the bent portion 12a is a fourth distance D4. The third distance D3 is larger than the fourth distance D4. Therefore, as shown in FIG. 4 , when the upper column 51 moves toward the X2 side, the X2-side tip 51a of the upper column 51 can move between the first portion 11 and the third portion 12 to a position close to the second portion 13 or a position in contact with the second portion 13.

[0045] 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 that fits into the upper column 51, the torque sensor (sensor device) 4 that is arranged between the output shaft 22 and the lower column 52, and the dust seal 1 that is arranged on the X1 side of the torque sensor 4 and extends annularly along the circumferential direction. The dust seal 1 has: a first portion 11 that is attached to the inner peripheral surface of the lower column 52 and extends in the axial direction; a second portion 13 that extends inward from a portion of the first portion 11 on the X2 side and has a first end 13a that is an end on the X1 side; and a third portion 12 that is provided on the inner peripheral side of the second portion 13 and has a second end 12d that is an end on the X1 side, with the second end 12d being located on the X1 side of the first end 13a. The upper column 51 is located between the first portion 11 and the third portion 12 in the radial direction of the central axis AX.

[0046] As described above, in Patent Document 1, the front end of the upper column overlaps with the dust seal when viewed from the axial direction. Therefore, when the upper column moves toward the front of the vehicle during a secondary collision, the front end of the upper column may come into contact with the dust seal, restricting the movement of the upper column and potentially reducing the amount of collision energy absorbed.

[0047] In contrast, in this embodiment, the dust seal 1 has a U-shaped cross section that is convex toward the X2 side (the front side of the vehicle) and is made up of the first portion 11, the second portion 13, and the third portion 12. In addition, the upper column 51 is located between the first portion 11 and the third portion 12 in the radial direction.

[0048] Therefore, when the upper column 51 moves toward the X2 side (toward the front of the vehicle) during a secondary collision, the tip 51 a of the upper column 51 is able to pass between the first portion 11 and the third portion 12 and move to the second portion 13 without hitting the first portion 11 or the third portion 12. In this way, according to this embodiment, the amount of axial movement of the upper column 51 can be increased during a secondary collision, and the amount of collision energy absorbed can be increased.

[0049] The dust seal 1 also has a first portion 11, a second portion 13 extending inward from a portion of the first portion 11 on the X2 side, and a third portion 12 extending and bending toward the X1 side from a bent portion 12a (an inner portion) on the inner side of the second portion 13. The upper column 51 is located between the first portion 11 and the third portion 12 in the radial direction of the central axis AX.

[0050] In this way, the third section 12 extends from the bent portion 12 a (the section on the inner periphery) toward the X1 side, which allows the axial length of the third section 12 to be set longer, thereby improving the sealing performance of the dust seal 1.

[0051] In particular, the upper column 51 being located between the first portion 11 and the third portion 12 in the radial direction means that the following condition is satisfied: a first distance D1 between the central axis AX and the outer peripheral surface of the upper column 51 is smaller than a second distance D2 between the central axis AX and the inner peripheral surface of the first portion 11 of the dust seal 1, and a third distance D3 between the central axis AX and the inner peripheral surface of the upper column 51 is larger than a fourth distance D4 between the central axis AX and the bent portion 12 a of the second portion 13.

[0052] The dust seal 1 has a reinforcing member 14. Specifically, the reinforcing member 14 is embedded in the first portion 11. Therefore, the dust seal 1 can be attached to the inner peripheral surface of the lower column 52 more firmly.

[0053] Second Embodiment Next, a second embodiment will be described. Fig. 5 is a cross-sectional view of a part of a steering device according to the second embodiment. A dust seal 1A according to the second embodiment includes a protrusion 15. This will be described in detail below.

[0054] As shown in Figure 5, a recess 52d is provided on the inner peripheral surface of the mounting portion 52c of the lower column 52. The recess 52d is recessed toward the outer periphery and has a rectangular cross section. The dust seal 1A has a protrusion 15 on the outer periphery surface of the first portion 11. The protrusion 15 protrudes toward the outer periphery and has a rectangular cross section. The protrusion 15 of the dust seal 1A fits into the recess 52d of the lower column 52. In this way, the first portion 11 of the dust seal 1A is attached to the lower column 52.

[0055] As explained above, in the dust seal 1A according to the second embodiment, the first portion 11 has the convex portion 15 that protrudes toward the outer periphery, and the inner circumferential surface of the lower column 52 is provided with the concave portion 52d that fits into the convex portion 15. Therefore, after the dust seal 1A is assembled to the lower column 52, axial positional deviation of the dust seal 1A with respect to the lower column 52 is suppressed.

[0056] [Third Embodiment] Next, a third embodiment will be described. Fig. 6A is a cross-sectional view of a portion of a steering device according to the third embodiment. Fig. 6B is a cross-sectional view taken along line VIB-VIB in Fig. 6A. Fig. 7 is a cross-sectional view showing a state after the input shaft has moved axially in Fig. 6A. Fig. 8 is a schematic view showing a procedure for inserting a lower column equipped with a dust seal onto an output shaft 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.

[0057] As shown in FIGS. 6A and 6B , 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 radially 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.

[0058] 6A, an end 12b of the third portion 12 of the dust seal 1B according to the third embodiment abuts against the X2-side side surface 33 of the key lock collar 3. More specifically, the end 12b of the third portion 12 abuts against the radially outer end of the side surface 33. Note that, also in the third embodiment, as shown in FIG. 7, when the upper column 51 moves toward the X2 side, the tip 51a on the X2 side of the upper column 51 can move past the inner circumferential side of the first portion 11 to a position close to the second portion 13.

[0059] The procedure for assembling a steering device 80B according to the third embodiment will be briefly described below. As shown in Figure 8, first, the key lock collar 3 is fitted onto the outer peripheral surface of the output shaft 22. Next, the dust seal 1B is fitted onto the inner peripheral surface of the lower column 52. Then, the lower column 52 fitted with the dust seal 1B is positioned on the outer peripheral side of the output shaft 22 fitted with the key lock collar 3, and moved downward in Figure 8. This causes the third portion 12 of the dust seal 1B to move downward while sliding on the outer peripheral surface of the key lock collar 3, resulting in the state shown in Figure 6A.

[0060] As described above, in the third embodiment, the annular key lock collar 3 is fitted onto the outer peripheral surface of the output shaft 22, and the lip portion 12c abuts against the key lock collar 3. In this way, the key lock collar 3 also serves to protect the torque sensor 4 from dust, etc., and therefore, for example, the length of the third portion 12 can be set to be short.

[0061] [Fourth embodiment] Next, a fourth embodiment will be described. Fig. 9 is a cross-sectional view of a portion of a steering device according to the fourth embodiment. A steering device 80C according to the fourth embodiment differs from the steering device 80B according to the third embodiment in that a dust seal 1C is provided. This will be described in detail below.

[0062] 5, the dust seal 1C has a protrusion 15 that fits into a recess 52d of the lower column 52. An end 12b of the third portion 12 of the dust seal 1C abuts against the side surface 33 of the key lock collar 3 on the X2 side.

[0063] As described above, in the fourth embodiment, the annular key lock collar 3 is fitted onto the outer peripheral surface of the output shaft 22, and the lip portion 12c abuts against the key lock collar 3. As a result, even in the case of a dust seal 1C in which the protrusion 15 is fitted into the recess 52d of the lower column 52, it is possible to make the third portion 12 of the dust seal 1C abut against the key lock collar 3.

[0064] Fifth Embodiment Next, a fifth embodiment will be described. Fig. 10 is a cross-sectional view of a portion of a steering device according to the fifth embodiment. A steering device 80D according to the fifth embodiment differs from the steering device 80B according to the third embodiment in the first annular member 66 and the dust seal 1D. This will be described in detail below.

[0065] As shown in FIG. 10 , the inner peripheral surface 66a of the first annular member 66 is fitted and fixed to the outer peripheral surface of the large-diameter portion 221h of the output shaft 22. The first annular member 66 extends annularly in the circumferential direction of the central axis AX. The first annular member 66 has a rectangular cross section. The first annular member 66 is located axially between the dust seal 1D and the key lock collar 3. That is, the first annular member 66 is located on the X2 side of the key lock collar 3. The axial length of the third portion 12D of the dust seal 1D is shorter than the axial length of the third portion 12 of the dust seal 1C shown in FIG. 9 . The end 12b of the third portion 12D of the dust seal 1D abuts against the X2-side surface 66b of the first annular member 66. Note that the inner periphery of the end 12Dd of the third portion 12D of the dust seal 1D may abut against the outer peripheral surface 66c of the first annular member 66. The outer peripheral surface 66c is an outer peripheral surface around the central axis AX (see FIGS. 2 and 3).

[0066] As described above, in the fifth embodiment, the first annular member 66 is fitted to the outer peripheral surface of the output shaft 22 at a position between the key lock collar 3 and the dust seal 1D in the axial direction. The lip portion 12c abuts against the first annular member 66. This allows the first annular member 66 to also provide dust protection and other functions for the torque sensor 4, so that, for example, the length of the third section 12 can be set shorter.

[0067] Sixth Embodiment Next, a sixth embodiment will be described. Fig. 11 is a cross-sectional view of a portion of a steering device according to the sixth embodiment. In the sixth embodiment, the shape of a third portion of a dust seal 1E differs from the shapes of the third portion of the dust seals according to the first to fifth embodiments. This will be described in detail below.

[0068] As shown in FIG. 11 , a dust seal 1E provided in a steering device 80E according to the sixth embodiment has a first portion 11, a second portion 13, and a third portion 12E. The second portion 13 has a first end 13a on the X1 side (one axial side). The first end 13a extends in a direction perpendicular to the central axis AX. In other words, the first end 13a is the X1-side side of the second portion 13. The third portion 12E has an inclined portion 12Ea and a lip portion 12Eb. The inclined portion 12Ea extends from an inner peripheral portion of the second portion 13 toward the X1 side. The lip portion 12Eb is provided on the inner peripheral side of the inclined portion 12Ea. For example, the lip portion 12Eb extends obliquely toward the inner peripheral side and the X2 side from an inner peripheral end portion 12Ec of the inclined portion 12Ea. The inner end 12Ec of the inclined portion 12Ea is a second end 12Ed, which is the end on the X1 side (one side in the axial direction) of the third section 12E. The lip portion 12Eb may have a shape that extends toward the inner side in a direction perpendicular to the central axis AX. Here, the second end 12Ed is located closer to the X1 side than the first end 13a. While FIG. 11 shows a reinforcing member 14 provided on the dust seal 1E, the reinforcing member 14 may be omitted.

[0069] The second annular member 67 extends annularly in a direction around the central axis AX (see, for example, FIG. 1 ). The second annular member 67 is fitted to the large diameter portion 221h of the first output shaft 221. The second annular member 67 is located axially between the torque sensor 4 and the key lock collar 3. When viewed radially, the second annular member 67 overlaps the dust seal 1E. The second annular member 67 has an inner circumferential surface 67a, an outer circumferential surface 67c, and end faces 67b and 67d. In a cross section including the central axis AX, the second annular member 67 is rectangular. The second annular member 67 is made of metal, such as iron or aluminum. The lip portion 12Eb of the dust seal 1E abuts against the outer circumferential surface 67c of the second annular member 67.

[0070] If the distance between the outer periphery of the key lock collar 3 and the central axis AX is defined as a fifth distance D5, the distance between the outer periphery of the second annular member 67 and the central axis AX is defined as a sixth distance D6, and the distance between the outer periphery of the magnet 41 and the central axis AX is defined as a seventh distance D7, the following dimensional relationship is established. The seventh distance D7 is equal to or less than the sixth distance D6. The fifth distance D5 is greater than the sixth distance D6 and the seventh distance D7.

[0071] Figure 12 is a cross-sectional view showing a state after the input shaft has moved axially in Figure 11. As shown in Figure 12, when the upper column 51 moves to the X2 side, the tip of the upper column 51 on the X2 side can move between the first portion 11 and the third portion 12E to a position close to the second portion 13 or to a position in contact with the second portion 13E.

[0072] Next, an assembly procedure for a steering device 80E according to the sixth embodiment will be described. Fig. 13A is an exploded perspective view of the steering device according to the sixth embodiment. Fig. 13B is a perspective view of the steering device according to the sixth embodiment after assembly is completed.

[0073] The shaft assembly 110 is disposed on the X1 side in FIG. 13A, the housing 100 is disposed on the X2 side in FIG. 13A, and the lower column 52 is disposed on the central side.

[0074] 13A , the shaft assembly 110 includes the output shaft 22, a torsion bar 223, a key lock collar 3, a second annular member 67, and a magnet 41. The lower column 52 is provided with an insertion opening 101 on the X1 side and an insertion opening 102 on the X2 side. The housing 100 has the stator 42 attached to the X1 side and the second output shaft 222 attached to the X2 side.

[0075] First, the lower column 52 is assembled to the housing 100. More specifically, the lower column 52 is moved to the X2 side as shown by the arrow, and the stator 42 of the housing 100 is inserted into the insertion opening 102 of the lower column 52.

[0076] Next, the lower column 52 and the shaft assembly 110 are assembled. In detail, the shaft assembly 110 is moved toward the X2 side as shown by the arrow, and the portion of the shaft assembly 110 from the torsion bar 223 to the key lock collar 3 is inserted into the insertion opening 101 of the lower column 52. This insertion positions the magnet 41 on the inner circumferential side of the stator 42, and positions the second annular member 67 on the inner circumferential side of the dust seal 1E.

[0077] Here, the seventh distance D7 is equal to or less than the sixth distance D6 and smaller than the fifth distance D5. This dimension allows the magnet 41 to easily pass through the lip portion 12Eb of the dust seal 1E during assembly. However, if the sixth distance D6 is too large, the magnet 41 will come into contact with the jig used for magnetizing the magnet. Therefore, it is preferable to set D6 ≧ D7 so that the magnet does not come into contact with the jig. Furthermore, because the third portion of the dust seal 1E has a generally U-shaped configuration with a convex shape toward the X1 side, the shaft assembly 110 can be smoothly inserted into the insertion opening 101 of the lower column 52 toward the X2 side. In other words, if the sixth distance D6 and the seventh distance D7 were larger than the fifth distance D5, the magnet 41 and the second annular member 67 would interfere with the dust seal 1E, preventing smooth assembly of the shaft assembly 110 to the lower column 52.

[0078] 13B, the X2 side end of the torsion bar 223 is connected to the X2 side end of the second output shaft 222 via the pin 224. This completes the assembly of the steering device 80E.

[0079] As described above, in the steering device 80E according to the sixth embodiment, the third portion 12E of the dust seal 1E has the inclined portion 12Ea extending from the inner peripheral portion of the second portion 13 toward the inner peripheral side and the X1 side, and the lip portion 12Eb provided on the inner peripheral side of the inclined portion 12Ea. The lip portion 12Eb abuts against the outer peripheral surface 67c of the second annular member 67.

[0080] According to this, the third section 12E has an inclined section 12Ea that extends inward and toward the X1 side from an inner peripheral portion of the second section 13. Therefore, also in the sixth embodiment, during a secondary collision, the tip end 51a of the upper column 51 can move toward the X2 side, pass between the first section 11 and the third section 12, and move to the vicinity of the second section 13. In this way, according to this embodiment, during a secondary collision, the amount of axial movement of the upper column 51 can be increased, and the amount of collision energy absorbed can be increased.

[0081] Furthermore, the second annular member 67 is fitted onto the outer periphery of the first output shaft 221, and the lip portion 12Eb abuts against the outer periphery 67c of the second annular member 67. Therefore, compared to an embodiment in which the second annular member 67 is not provided, the length of the lip portion 12Eb can be set shorter.

[0082] [Seventh embodiment] Next, a seventh embodiment will be described. Fig. 14 is a cross-sectional view of a portion of a steering device according to the seventh embodiment. A steering device 80F according to the seventh embodiment differs from the steering device 80E according to the sixth embodiment in that a first resin ring 71 is provided. This will be described in detail below.

[0083] The second annular member 67 is fitted to the large diameter portion 221h of the first output shaft 221. A first resin ring 71 is press-fitted onto the outer periphery of the second annular member 67. The first resin ring 71 extends annularly in a direction circumferential to the central axis AX (see FIG. 1, for example). The first resin ring 71 is rectangular in a cross section including the central axis AX. That is, the first resin ring 71 has an inner circumferential surface 71a, an end face 71b, an outer circumferential surface 71c, and an end face 71d. The inner circumferential surface 71a is fitted to (abuts against) the outer circumferential surface 67c of the second annular member 67. The outer circumferential surface 71c is a cylindrical surface extending in a direction circumferential to the central axis AX. In a cross section including the central axis AX, the axial center of the first resin ring 71 and the axial center of the second annular member 67 substantially coincide with each other. The lip portion 12Eb of the dust seal 1E abuts against the outer circumferential surface 71c of the first resin ring 71.

[0084] As described above, in the steering device 80F according to the seventh embodiment, the annular first resin ring 71 is fitted onto the outer periphery of the second annular member 67 made of metal, and the lip portion 12Eb abuts against the outer periphery 71c of the first resin ring 71.

[0085] The second annular member 67 is made of metal and rotates integrally with the output shaft 22. The dust seal 1E does not rotate and has a lip portion 12Eb. Therefore, if the lip portion 12Eb abuts against the second annular member 67, the relative rotation between the lip portion 12Eb and the second annular member 67 may generate abnormal noise. Therefore, a first resin ring 71 is fitted to the outer periphery of the second annular member 67 so that the lip portion 12Eb abuts against the first resin ring 71. This reduces the sliding resistance between the lip portion 12Eb and the first resin ring 71 compared to the sliding resistance between the lip portion 12Eb and the second annular member 67, thereby suppressing abnormal noise when the output shaft 22 rotates. Note that instead of fitting the first resin ring 71, the outer periphery of the second annular member 67 may be resin-coated.

[0086] Eighth Embodiment Next, an eighth embodiment will be described. Fig. 15 is a cross-sectional view of a portion of a steering device according to the eighth embodiment. A steering device 80G according to the eighth embodiment differs from the steering device 80E according to the sixth embodiment in that a second resin ring 72 is provided. This will be described in detail below.

[0087] A second annular member 67 is fitted onto the large diameter portion 221h of the first output shaft 221. A second resin ring 72 is press-fit onto the outer periphery of the second annular member 67. The second resin ring 72 extends annularly in a direction circumferentially about the central axis AX (see FIG. 1, for example). The second resin ring 72 has a substantially rectangular shape in a cross section including the central axis AX. That is, the second resin ring 72 has an inner circumferential surface 72a, an end face 72b, an outer circumferential surface 72c, and an end face 72d. The inner circumferential surface 72a is fitted onto (contacts) the outer circumferential surface 67c of the second annular member 67.

[0088] Here, the outer peripheral surface 72c of the second resin ring 72 is provided with a V-shaped groove 72e recessed toward the inner peripheral side in a cross section including the central axis AX, and the grooves 72e are arranged in multiple axial directions. The grooves 72e extend in the direction around the central axis AX. The grooves 72e are capable of storing grease. Note that the cross-sectional shape of the grooves 72e is not limited to a V-shape, and various shapes such as an arc shape or a U-shape can be used.

[0089] As described above, in the steering device 80G according to the eighth embodiment, the annular second resin ring 72 is fitted onto the outer periphery of the second annular metal member 67, and the lip portion 12Eb abuts against the outer periphery 72c of the second resin ring 72. A V-shaped groove 72e recessed toward the inner periphery is provided on the outer periphery 72c of the second resin ring 72 in a cross section including the central axis AX.

[0090] Due to the relative rotation between the lip portion 12Eb and the second resin ring 72, the tip of the lip portion 12Eb slides in contact with the outer circumferential surface 72c of the second resin ring 72. Here, grease accumulates in the recessed groove 72e, reducing the sliding resistance between the lip portion 12Eb and the second resin ring 72 and suppressing abnormal noise.

[0091] Ninth Embodiment Next, a ninth embodiment will be described. Fig. 16 is a cross-sectional view of a steering device according to the ninth embodiment. A steering device 80E according to the ninth embodiment differs from the steering device 80 according to the first embodiment in that it has a steering shaft 2E. This will be described in detail below.

[0092] 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.

[0093] In contrast, in the ninth embodiment, the steering shaft 2E includes an input shaft 21E and an output shaft 22E. The input shaft 21E is solid, and the output shaft 22E is cylindrical. The X1 side end of the output shaft 22E is inserted into the inner peripheral side of the X2 side end of the input shaft 21E and spline-fitted.

[0094] As described above, in the ninth embodiment, it is also possible to adopt a mode in which the input shaft 21E is solid and the output shaft 22E is cylindrical.

[0095] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1E Dust seal 11 First portion 11a End 11b End 12, 12D, 12E Third portion 12Dd End 12Ea Inclined portion 12Eb Lip portion 12Ec End 12Ed Second end 12a Bent portion (inner peripheral portion) 12b End 12c Lip portion 12d Second end 13 Second portion 13a First end 14 Reinforcing member 14a Cylindrical portion 14b Annular portion 15 Convex portion 2, 2E Steering shaft 21, 21E Input shaft 21a End 21b End 21c Spline portion 21d Tip 22, 22E Output shaft 221 First output shaft 221a End 221b End 221c DESCRIPTION OF SYMBOLS Outer circumferential surface 221d Radial wall portion 221e Spline portion 221f Medium diameter portion 221g Small diameter portion 221h Large diameter 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 Tip 52 Lower column 52a Fitting portion 52b Opening 52c Mounting portion 52d Recessed portion 60 Vehicle body mounting member 61 Vehicle body support portion 62 Worm wheel 63, 64, 65 Bearing 66 First annular member 66a Inner circumferential surface 66b Surface 66c Outer circumferential surface 67 Second annular member 67a Inner peripheral surface 67b End surface 67c Outer peripheral surface 67d End surface 71 First resin ring 71a Inner peripheral surface 71b End surface 71c Outer peripheral surface 71d End surface 72 Second resin ring 72a Inner peripheral surface 72b End surface 72c Outer peripheral surface 72d End surface 72e Groove 80, 80B, 80C, 80D, 80E, 80F 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 Housing 101, 102 Insertion port 110 Shaft assembly AX Center axis BL Bolt

Claims

1. An engine 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, fitted 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 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 is a first section attached to an inner peripheral surface of the lower column and extending in the axial direction; a second section extending inward from a section of the first section on the other side in the axial direction and having a first end that is an end on one side in the axial direction; and a third section provided on the inner peripheral side of the second section and having a second end that is an end on one side in the axial direction, the second end being located on one side in the axial direction of the first section; 2. A steering device according to claim 1, wherein the third portion of the dust seal extends from an inner peripheral portion of the second portion toward one side in the axial direction.

3. The steering device according to claim 2, wherein the dust seal has a reinforcing member.

4. A steering device as set forth in claim 2 or 3, wherein the first portion of the dust seal has a convex portion that protrudes outward, and the inner peripheral surface of the lower column is provided with a concave portion that fits into the convex portion.

5. A steering device according to claim 2 or 3, wherein an annular key lock collar is fitted onto the outer peripheral surface of the output shaft, and the third portion abuts against the key lock collar.

6. A steering device as set forth in claim 2 or 3, wherein an annular key lock collar is fitted onto the outer peripheral surface of the output shaft, a first annular member is fitted onto the outer peripheral surface of the output shaft at a position between the key lock collar and the dust seal in the axial direction, and the third portion abuts against the first annular member.

7. A steering device as described in claim 1, wherein a second annular member is fitted onto the outer peripheral surface of the output shaft, and the third portion of the dust seal has an inclined portion extending from an inner peripheral portion of the second portion toward the inner peripheral side and to one side in the axial direction, and a lip portion provided on the inner peripheral side of the inclined portion, and the lip portion abuts against the outer peripheral surface of the second annular member.

8. A steering device as set forth in claim 7, wherein the second annular member is made of metal, a first annular resin ring is fitted onto the outer periphery of the second annular member, the outer periphery of the first resin ring is a cylindrical surface extending in a direction around the central axis, and the lip portion abuts against the cylindrical surface of the first resin ring.

9. A steering device as described in claim 7, wherein an annular second resin ring is fitted onto the outer periphery of the second annular member, and in a cross section including the central axis, the outer periphery of the second resin ring is provided with a recessed groove that is recessed towards the inner periphery and is capable of storing grease, and the lip portion abuts against the outer periphery of the second resin ring.

Images