Steering column device

Abstract

The present invention relates to a steering column device (1), which includes a cylindrical inner tube (17) and a cylindrical outer tube (16), the outer tube being fixed to the inner tube (17) by being externally fitted to slide along the axial direction of the inner tube (17) and being elastically reduced in diameter, wherein the outer tube (16) is configured to have a first slit (71) and a second slit (72) to be reduced in diameter. A stress relief portion (72a) is provided at the second slit (72). The contour shape of the stress relief portion (72a) is set to include an elliptical arc-shaped portion, the major axis direction of the elliptical arc-shaped portion being a direction intersecting with the second slit (72).

Description

Technical Field

[0001] The invention relates to a steering column arrangement. Background Art

[0002] Conventionally, there is a steering column that supports the steering shaft of a vehicle in a rotatable manner. For example, the steering column of Japanese Unexamined Patent Application Publication No. 2009-6847 (JP 2009-6847A) has a double-tube structure including an inner column and an outer column. A first slit extending along the axis of the outer column and a second slit continuous with the first slit and extending in the circumferential direction of the outer column are provided in the outer column. In addition, a pair of clamping portions facing each other are provided on the outer column, wherein the first slit is disposed between the pair of clamping portions. These clamping portions are clamped by a column bracket fixed to the vehicle body. The inner column is tightened in the following manner: the diameter of the outer column is reduced due to elastic deformation of the clamping portions in a direction in which the clamping portions approach each other by operation of a clamping device provided on the column bracket. Therefore, the relative movement between the inner column and the outer column in the axial direction is restricted. Summary of the invention

[0003] According to the steering column of JP 2009-6847A, the rigidity when the diameter of the outer column is reduced is reduced by providing the first slit and the second slit in the outer column. The force required to reduce the diameter of the outer column can be reduced by the amount by which the rigidity of the outer column is reduced, and thus the force to operate the clamping device can be reduced by the amount by which the rigidity of the outer column is reduced. Therefore, the operability of the clamping device is ensured.

[0004] However, when the diameter of the outer column is reduced, stress is concentrated on the distal end portion of the second slit. In order to alleviate the stress concentration at the distal end portion, a stress concentration relief portion is provided at the distal end portion of the second slit. The stress concentration relief portion is open in a circular shape having a diameter greater than the width of the portion of the second slit up to the distal end portion. The curvature of the distal end portion of the second slit is made smaller by setting the diameter of the stress concentration relief portion to a value greater than the width of the portion of the second slit up to the distal end portion. Therefore, when the diameter of the outer column is reduced, the stress concentration on the distal end portion of the second slit is relieved.

[0005] However, in the steering column of JP 2009-6847A, the following situation may occur. For example, when the steering wheel is operated while the rotation of the steering shaft is restricted by the steering lock device, a torsional force around the axis of the steering wheel is applied to the outer column. In this case, stress may still be concentrated on the distal end portion of the second slit including the circular stress concentration mitigation portion.

[0006] The present invention provides a steering column device capable of more appropriately relaxing stress concentration when torsional force is applied to an outer tube.

[0007] The steering column device according to the first aspect of the present invention is a steering column device that supports a steering shaft in a rotatable manner. The steering column device includes a cylindrical inner tube and a cylindrical outer tube, and the outer tube is fixed to the inner tube by being fitted externally to slide in the axial direction of the inner tube and being elastically reduced in diameter. The outer tube is configured to have a first slit and a second slit to be reduced in diameter, the first slit extending in the axial direction of the outer tube, and the second slit is continuous with the first slit and extends in a direction intersecting with the first slit. A stress relief portion is provided at the end portion of the second slit located on the side opposite to the first slit, and the stress relief portion is opened to have a width longer than the width of the second slit up to the end portion. The contour shape of the stress relief portion is set to include an elliptical arc-shaped portion, and the major axis direction of the elliptical arc-shaped portion is the direction intersecting with the second slit.

[0008] With this configuration, the curvature of the end portion of the second slit can be made smaller in a limited space by setting the contour shape of the end portion of the second slit to include an elliptical arc-shaped portion whose major axis direction is a direction intersecting the second slit. Therefore, when a torsional force is applied to the outer tube for some reason, stress concentration on the end portion of the second slit in the outer tube can be more appropriately suppressed.

[0009] In this aspect, an opening portion for inserting the additional component is provided in the outer tube, the opening portion is located at a distance from the stress relaxation portion in the axial direction of the outer tube, and the stress relaxation portion can extend toward the side opposite to the opening portion along the axial direction of the outer tube.

[0010] With this configuration, compared with the case where the stress relaxation portion extends toward the opening portion side in the axial direction of the outer tube, the rigidity between the second slit of the outer tube and the opening portion can be easily ensured.

[0011] In this regard, the additional component may be a locking member that engages with a portion of the steering shaft and restricts rotation of the steering shaft.

[0012] With this configuration, when torque is applied to the steering shaft while rotation of the steering shaft is restricted by the locking member, torsional force is applied to the outer tube. By providing the stress relaxation portion at the end portion of the second slit, stress concentration on the end portion of the second slit can be appropriately suppressed.

[0013] In this regard, the stress relaxation portion may extend toward both sides of the portion of the second slit up to the stress relaxation portion in the width direction. This configuration may be adopted in the case where there is no opening portion near the second slit in the outer tube.

[0014] In this regard, the stress relaxation portion and the portion of the second slit up to the stress relaxation portion can be smoothly continuous. With this configuration, stress concentration on the peripheral portion of the second slit in the outer tube is suppressed.

[0015] In this regard, the contour shape of the stress relief portion may be an ellipse. It is conceivable that the contour shape of the end portion of the second slit is set to a circular shape, and when it is assumed that the stress relief portion is provided in an area having the same size, the curvature of the elliptical arc in the major axis direction is smaller than the curvature of the arc. Therefore, by adopting an elliptical shape as the contour shape of the stress relief portion, the curvature of the end portion of the second slit can be further reduced within a limited space.

[0016] According to the steering column device of the present invention, it is possible to more appropriately alleviate stress concentration when torsional force is applied to the outer tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which:

[0018] Figure 1 is a schematic diagram showing a schematic configuration of an embodiment of a steering column device;

[0019] Figure 2 It is along Figure 1 A schematic cross-sectional view taken along line II-II in FIG.

[0020] Figure 3 is a front view of the outer tube according to the embodiment when viewed from the side opposite to the fixed portion of the vehicle body;

[0021] Figure 4 is a cross-sectional view of a main portion of a steering column device according to an embodiment, taken along a plane coplanar / parallel to a main symmetry axis of the steering column, i.e., a longitudinal axis thereof;

[0022] Figure 5 is a side view showing the vicinity of the distal end of the slit of the outer tube according to the embodiment;

[0023] Figure 6 is a side view showing the shape of a distal end portion of a slit of an outer tube according to a comparative example;

[0024] Figure 7 is a side view showing the shape of the distal end portion of the slit of the outer tube according to the embodiment;

[0025] Figure 8 is a side view of a main part showing the shape of a distal end portion of a slit of an outer tube according to another embodiment; and

[0026] Fig. 9 is a side view of a main part showing the shape of a distal end portion of a slit of an outer tube according to another embodiment. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the steering column device will be described. Figure 1 As shown in FIG, a steering column device 1 rotatably supports a steering shaft 2. A first end portion of the steering shaft 2 is connected to a steering wheel 3. A second end portion of the steering shaft 2 is engaged with a rack shaft extending in the left-right direction of the vehicle body via an intermediate shaft and a pinion shaft. Both end portions of the rack shaft are connected to a left steering wheel and a right steering wheel via tie rods. The direction of the steering wheel changes according to the operation of the steering wheel 3.

[0028] The steering shaft 2 has an outer shaft 11 and an inner shaft 12. The outer shaft 11 and the inner shaft 12 are connected to each other by, for example, a spline connection. The outer shaft 11 and the inner shaft 12 can rotate integrally and can move relatively in the axial direction of each other. The steering shaft 2 is arranged obliquely with respect to the front-rear direction X1 of the vehicle so that the steering wheel 3 is positioned on the upper side.

[0029] The steering column device 1 has a steering column 15 fixed to a fixed portion 13 such as a frame of a vehicle body. The steering shaft 2 is inserted through the steering column 15. The steering shaft 2 is rotatably supported by the steering column 15 via a fulcrum member.

[0030] The steering column 15 has an outer tube 16 and an inner tube 17. Each of the outer tube 16 and the inner tube 17 has a tubular shape. The outer tube 16 and the inner tube 17 are fitted to each other so as to be movable relative to each other in the axial direction of the steering shaft 2. The inner tube 17 is inserted into the outer tube 16 from the side opposite to the steering wheel 3. The outer tube 16 is fixed to the fixing portion 13 on the vehicle body side via a column bracket 21.

[0031] like Figure 2 As shown in FIG. 1 , the column bracket 21 has an upper bracket 22, a tilt bracket 23, and two clamp brackets 24a and 24b. The upper bracket 22 has a left-right direction ( Figure 2 The upper bracket 22 has a flat plate shape extending in the left-right direction. Mounting seats 22a are provided at both ends of the upper bracket 22. The upper bracket 22 is fixed to the fixing portion 13 of the vehicle body through the mounting seats 22a and 22a. Specifically, it is described as follows.

[0032] In other words, two bolts 31 and 31 are provided on the fixing portion 13 to protrude from the fixing portion 13. The bolts 31 and 31 extend so that the axial direction Z1 of the bolts 31 and 31 intersects with the vertical direction. The bolts 31 and 31 are provided one after another on the left and right sides of the vehicle body relative to the steering shaft 2 when viewed in the axial direction of the steering shaft 2. The bolt 31 is a stud bolt having external threads on both ends of the bolt 31. The first end portion of the bolt 31 is screwed into the fixing portion 13. The second end portion of the bolt 31 passes through the mounting seat 22a. The mounting seat 22a is fixed to the fixing portion 13 by tightening the nut 32 on the second end portion of the bolt 31. A washer 33 is disposed between the nut 32 and the mounting seat 22a.

[0033] The tilt bracket 23 is fixed to the upper bracket 22. The tilt bracket 23 has a square U-shape that is open toward the side opposite to the upper bracket 22. The tilt bracket 23 has a connecting plate 41 and two side plates 42a and 42b. The connecting plate 41 is fixed to the surface of the upper bracket 22 opposite to the fixing portion 13 of the vehicle body ( Figure 2 The two side plates 42a and 42b are connected to the two side edges of the connecting plate 41 in the left-right direction of the vehicle body when viewed in the axial direction of the steering shaft 2. The two side plates 42a and 42b extend toward the side opposite to the fixing portion 13 of the vehicle body (at Figure 2 Long holes extending along the axial direction Z1 of the bolt 31 are provided in the two side plates 42a, 42b.

[0034] The two clamping brackets 24a and 24b are formed by bending a metal plate into a square U-shape. The two clamping brackets 24a and 24b are fixed to the outer peripheral surface of the outer tube 16. The two clamping brackets 24a and 24b extend toward the side opposite to the fixing portion 13 of the vehicle body (at Figure 2 The two clamping brackets 24a and 24b are located inside the two side plates 42a and 42b of the tilt bracket 23 in the left-right direction of the vehicle body when viewed in the axial direction of the steering shaft 2, and are held in a state where the two clamping brackets 24a and 24b are in contact with the two side plates 42a and 42b. The two clamping brackets 24a and 24b are provided with long holes extending in the axial direction of the steering shaft 2.

[0035] The tilt bracket 23 and the two clamp brackets 24a and 24b are connected via a tightening shaft 51 constructed by bolts. The two clamp brackets 24a and 24b are supported by the tightening shaft 51 so that the positions of the two clamp brackets 24a and 24b can be adjusted relative to the tilt bracket 23. The tightening shaft 51 is arranged in a direction intersecting with the axial direction of the steering shaft 2 ( Figure 2The tightening shaft 51 passes through the long holes of the side plates 42a and 42b of the tilt bracket 23 and the long holes of the two clamping brackets 24a and 24b. The nut 53 is screwed into the tip end portion of the tightening shaft 51 that has passed through, and the tip end portion is the end portion located on the side opposite to the head portion 52. On the tightening shaft 51, the rod 54 is rotatably supported between the head portion 52 and one clamping bracket 24a ( Figure 2 Between the left clamping bracket 24a).

[0036] A first cam 55 is integrally provided on the side surface of the base end portion of the rod 54 located on the clamping bracket 24a side. In addition, a second cam 56 is provided between the first cam 55 and one side plate 42a of the tilt bracket 23. The second cam 56 is provided in a state where the relative rotation relative to the side plate 42a is restricted. A plurality of protrusions are provided at intervals on the peripheral portion of the side surface of the first cam 55 located on the second cam 56 side. In addition, a plurality of protrusions are provided at intervals on the peripheral portion of the side surface of the second cam 56 located on the first cam 55 side. The rotation position of the first cam 55 is switched between the first rotation position and the second rotation position by the rotation operation of the rod 54. The first rotation position is a position where the protrusion of the first cam 55 is engaged between the protrusions of the second cam 56. The second rotation position is a position where the protrusion of the first cam 55 is mounted on the protrusion of the second cam 56.

[0037] When the rotation position of the first cam 55 is switched from the first rotation position to the second rotation position by the rotation operation of the rod 54, the first cam 55 rotates relatively with respect to the second cam 56, and the protruding portion of the first cam 55 is mounted on the protruding portion of the second cam 56 in accordance with the rotation. Since the movement of the rod 54 in the direction along the tightening shaft 51 is restricted, the second cam 56 attempts to move toward the nut 53 side by an amount that causes the protruding portion of the first cam 55 to be mounted on the protruding portion of the second cam. Accordingly, the two side plates 42a and 42b of the tilt bracket 23 are elastically deformed in a direction approaching each other, and thus the two clamping brackets 24a and 24b are pressed between the second cam 56 and the nut 53. Therefore, the relative movement of the two clamping brackets 24a and 24b with respect to the tilt bracket 23 is restricted.

[0038] In addition, the two clamping brackets 24a and 24b are elastically deformed in a direction approaching each other via the two side plates 42a and 42b of the inclined bracket 23. Here, a slit 61 is provided in a portion of the outer tube 16 located between the two clamping brackets 24a and 24b. The slit 61 has a portion extending from the first end to the second end in the axial direction of the outer tube 16. Therefore, the outer tube 16 is elastically deformed in such a manner that the gap between the slits 61 is narrowed by narrowing the gap between the two clamping brackets 24a and 24b. In other words, the outer tube 16 is elastically deformed so that the inner diameter of the outer tube 16 becomes smaller, and thus the outer peripheral surface of the inner tube 17 is tightened. Therefore, the relative movement of the outer tube 16 relative to the inner tube 17 in the axial direction is restricted.

[0039] When the position of the steering wheel 3 is changed, the rotation position of the first cam 55 can be switched from the second rotation position to the first rotation position by the rotation operation of the rod 54. By fitting the protruding portion of the first cam 55 between the protruding portions of the second cam 56, the tightening of the two side plates 42a and 42b of the tilt bracket 23 in the direction of approaching each other and the tightening of the two clamping brackets 24a and 24b in the direction of approaching each other are released. By elastically returning the two side plates 42a and 42b of the tilt bracket 23 and the two clamping brackets 24a and 24b to their original positions, the distance between the two side plates 42a and 42b and the distance between the two clamping brackets 24a, 24b are increased respectively.

[0040] Therefore, the force of the two side plates 42a and 42b of the tilt bracket 23 clamping the two clamping brackets 24a and 24b is weakened. Therefore, the outer tube 16 to which the two clamping brackets 24a and 24b are fixed can move relative to the tilt bracket 23 in the vertical direction. The position of the steering wheel 3 in the vertical direction can be adjusted by moving the steering wheel 3 in the vertical direction. In addition, by releasing the tightening of the inner tube 17 by the outer tube 16, the outer tube 16 can move relative to the inner tube 17 in the axial direction. The position of the steering wheel 3 in the axial direction can be adjusted by moving the steering wheel 3 in the axial direction.

[0041] Next, the outer tube 16 will be described in detail. Figure 3 As shown in FIG. 1 , a slit 61 and a rectangular opening portion 62 are provided in the peripheral wall of the outer tube 16. The opening portion 62 is located between the slit 61 and the end portion of the outer tube 16 located on the steering wheel 3 side in the axial direction ( Figure 3 between the right end portion in ).

[0042] like Figure 4As shown in FIG. 1 , a locking recessed portion 63 is provided in the peripheral wall of the outer shaft 11. The locking recessed portion 63 extends in the axial direction of the outer shaft 11. The position of the locking recessed portion 63 of the outer shaft 11 and the position of the opening portion 62 of the outer tube 16 are aligned in the axial direction of the outer shaft 11. Therefore, during one rotation of the outer shaft 11, a locked state in which the locking recessed portion 63 and the opening portion 62 are aligned with each other in the rotation direction of the outer shaft 11 is formed.

[0043] In a state where the locking recessed portion 63 of the outer shaft 11 and the opening portion 62 of the outer tube 16 are aligned with each other in the rotation direction of the outer shaft 11, the locking member 64 of the steering lock device is inserted into the locking recessed portion 63 through the opening portion 62. The locking member 64 moves between a locking position and an unlocking position in conjunction with, for example, the operation of an ignition key. The locking position is a position where the tip end of the locking member 64 is inserted into the locking recessed portion 63 of the outer shaft 11 through the opening portion 62 of the outer tube 16. The unlocking position is a position where the tip end of the locking member 64 is pulled out of the locking recessed portion 63 or the opening portion 62.

[0044] When the ignition key is turned from the "on" position of the vehicle power supply to the locked position, the locking member 64 moves from the unlocked position to the locked position. When the steering shaft 2 is about to rotate by the operation of the steering wheel 3, the inner surface of the locking recessed portion 63 of the outer shaft 11 engages with the locking member 64. Therefore, the rotation of the steering shaft 2 is restricted, and thus the steering wheel 3 is restricted. On the other hand, when the ignition key is turned from the locked position of the power supply to the "on" position, the locking member 64 moves from the locked position to the unlocked position. Therefore, the rotation of the steering wheel 3 is allowed.

[0045] like Figure 3 As shown in FIG. 1 , the slit 61 has a first slit 71 and a second slit 72. The first slit 71 and the second slit 72 are continuous with each other and have an L-shape as a whole.

[0046] The first slit 71 extends in the axial direction of the outer tube 16. The first slit 71 is provided at an end portion ( Figure 3 The first slit 71 is formed in a range from the left end portion of the first slit 71 on the steering wheel 3 side to the vicinity of the center of the outer tube 16 in the axial direction. The end portion of the first slit 71 opposite to the steering wheel 3 is open. The second slit 72 is formed from the end portion of the first slit 71 on the steering wheel 3 side ( Figure 3 The second slit 72 and the opening portion 62 are adjacent to each other in the axial direction of the outer tube 16 with a predetermined interval therebetween.

[0047] like Figure 5As shown in FIG. 1 , a stress relief portion 72a is provided at an end portion of the second slit 72. The end portion of the second slit 72 is an end portion of the second slit 72 located on the side opposite to the first slit 71. The stress relief portion 72a opens in an elliptical shape whose major axis is greater than the width of the portion of the second slit 72 up to the stress relief portion 72a. The stress relief portion 72a is directed toward the side opposite to the opening portion 62 in the axial direction of the outer tube 16 ( Figure 5 In other words, the stress relief portion 72a is not provided so that the portion up to the stress relief portion 72a based on the second slit 72 extends toward the opening portion 62 side ( Figure 5 The stress relaxation portion 72a and the portion of the second slit 72 up to the stress relaxation portion 72a are continuous with each other via a smooth curved surface.

[0048] Now, after the adjustment of the position of the steering wheel 3 is completed, the rotation position of the first cam 55 is switched from the first rotation position to the second rotation position by the rotation operation of the lever 54. According to this operation, the two side plates 42a and 42b of the tilt bracket 23 are tightened in the direction in which the two side plates 42a and 42b approach each other, so the relative movement of the two clamping brackets 24a and 24b with respect to the tilt bracket 23 is restricted. In addition, the diameter of the portion of the outer tube 16 provided with the slit 61 is reduced to tighten the outer peripheral surface of the inner tube 17. Therefore, the relative movement of the outer tube 16 with respect to the inner tube 17 in the axial direction is restricted.

[0049] Here, the slit 61 provided in the outer tube 16 between the two clamp brackets 24a and 24b has not only the first slit 71 extending in the axial direction of the outer tube 16 but also the second slit 72 extending in the circumferential direction of the outer tube 16. Therefore, the rigidity becomes lower than the rigidity of the other parts in the case where the diameter of the portion of the outer tube 16 provided with the slit 61 is reduced. Since the operating force on the rod 54 required to reduce the diameter of the outer tube 16 becomes smaller, the operability of the rod 54 is improved.

[0050] Next, the operation of the stress relief portion 72a will be described. When the ignition key is operated from the "on" position of the vehicle power source to the lock position, the lock member 64 is inserted into the lock recessed portion 63 of the outer shaft 11 through the opening portion 62 of the outer tube 16, and thus the rotation of the steering shaft 2 is restricted. In this state, for example, when the steering wheel 3 is to be operated, a torsional force is applied to the outer tube 16 via the portion where the opening portion 62 is provided. The torsional force is transmitted to the slit 61 as a torque around the axis of the outer tube 16. At this time, stress may be concentrated on the tip end portion of the second slit 72, which is the portion of the outer tube 16 that is closest to the opening portion 62 in the slit 61 and extends in the circumferential direction of the outer tube 16.

[0051] In this regard, an elliptical stress relief portion 72a is provided at the end portion of the second slit 72, and the major axis of the elliptical stress relief portion 72a is larger than the width up to the end portion. In other words, by setting the contour shape of the end portion of the second slit 72 to include an elliptical arc-shaped portion, in which the direction intersecting the second slit 72 is the direction of the major axis of the elliptical arc-shaped portion, the curvature of the end portion of the second slit 72 can be further reduced in a limited space. Therefore, when a torsional force is applied to the outer tube 16, it becomes difficult for stress to be concentrated on the end portion of the second slit 72 including the stress relief portion 72a. Incidentally, when the curvature of the elliptical arc as the contour shape of the end portion of the second slit 72 becomes smaller, in other words, when the curvature radius of the elliptical arc becomes larger, the stress concentration at the end portion of the second end portion 72 is further relieved.

[0052] like Figure 6 As shown in the comparative example in, it is also conceivable to set the contour shape of the end portion of the second slit 72, that is, the stress relief portion 72a, to, for example, a circular shape whose diameter is larger than the width of the portion of the second slit 72 up to the stress relief portion 72a.

[0053] However, when it is assumed that the circular stress relief portion 72a and the elliptical stress relief portion 72a are provided in a region having the same size, for example, the curvature of the arc becomes greater than the curvature of the elliptical arc in the major axis direction. Therefore, although the situation differs depending on the diameter of the circular stress relief portion 72a, when torsion is applied to the outer tube 16, stress is concentrated on the end portion of the second slit 72 including the circular stress relief portion 72a.

[0054] In order to further relieve stress concentration at the end portion of the second slit 72, the diameter of the circular stress relief portion 72a may be set to a larger value. However, when the diameter of the stress relief portion 72a is set to a larger value, the opening area of ​​the stress relief portion 72a becomes larger, so the rigidity of the portion of the outer tube 16 provided with the slit 61 decreases. In addition, due to space limitations on the outer peripheral surface of the outer tube 16, there is a limit to the increase in the size of the stress relief portion 72a.

[0055] In this regard, by setting the contour shape of the stress relieving portion 72a to an elliptical shape, the curvature of the end portion of the second slit 72 can be set smaller in a limited space while suppressing an increase in the opening area of ​​the stress relieving portion 72a.

[0056] like Figure 7As shown by the double dotted line in , when a circular shape is adopted as the contour shape of the stress relief portion 72a, when a curvature similar to the curvature obtained when an elliptical shape is adopted as the contour shape of the stress relief portion 72a at the end portion of the second slit 72 is to be obtained, the opening area of ​​the circular stress relief portion 72a is larger than the opening area of ​​the elliptical stress relief portion 72a.

[0057] Therefore, by adopting an elliptical shape as the contour shape of the stress relaxing portion 72 a , it is possible to more effectively relax stress concentration at the end portion of the second slit 72 while suppressing an increase in the opening area of ​​the stress relaxing portion 72 a .

[0058] In addition, the stress relief portion 72a extends toward the side opposite to the opening portion 62 in the axial direction of the outer tube 16. Therefore, compared with the case where the stress relief portion 72a extends toward the opening portion 62 side, the rigidity of the portion of the outer tube 16 between the second slit 72 and the opening portion 62 is ensured.

[0059] Therefore, according to the embodiment, the following effects can be obtained. By setting the contour shape of the end portion of the second slit 72 to include an elliptical arc-shaped portion having a direction intersecting the second slit 72 as a major axis direction, the curvature of the end portion of the second slit 72 can be further reduced in a limited space. Therefore, when a torsional force is applied to the outer tube 16, stress concentration on the end portion of the second slit 72 in the outer tube 16 can be more appropriately suppressed.

[0060] Specifically, an elliptical shape is adopted as the contour shape of the stress relief portion 72a provided at the end portion of the second slit 72. It is conceivable that the contour shape of the end portion of the second slit 72 is set to a circular shape, and for example, when it is assumed that the circular stress relief portion 72a and the elliptical stress relief portion 72a are provided in an area having the same size, the curvature of the elliptical arc in the major axis direction is smaller than the curvature of the arc. Therefore, by adopting an elliptical shape as the contour shape of the stress relief portion 72a, the curvature of the end portion of the second slit 72 can be further reduced within a limited space. Therefore, when a torsional force is applied to the outer tube 16, the stress concentration on the end portion of the second slit 72 can be more effectively relieved.

[0061] The stress relaxation portion 72a extends toward the side opposite to the opening portion 62 in the axial direction of the outer tube 16. Therefore, the rigidity of the portion of the outer tube 16 between the second slit 72 and the opening portion 62 can be ensured. The supporting rigidity of the steering shaft 2 in the outer tube 16 is also ensured.

[0062] The stress relieving portion 72a and the portion of the second slit 72 up to the stress relieving portion 72a are continuous via a smooth curved surface. Therefore, it is possible to suppress stress concentration on the peripheral portion of the end portion of the second slit 72.

[0063] The embodiment may be modified as follows. A plurality of locking recessed portions 63 may be provided in the outer shaft 11 at predetermined intervals along the circumferential direction of the outer shaft 11. By inserting the locking member 64 of the steering lock device through the opening portion 62 of the outer tube 16 into any of the locking recessed portions 63, the rotation of the steering shaft 2 is restricted.

[0064] As a portion into which the locking member 64 of the steering lock device is inserted, a hole passing through the peripheral wall of the outer shaft 11 may be adopted instead of the locking recessed portion 63. In the embodiment, although the slit 72 extends in the circumferential direction of the outer tube 16 to be orthogonal to the first slit 71, the second slit 72 may be provided to intersect the first slit 71 at a predetermined acute angle or obtuse angle.

[0065] Depending on the use of the product, etc., the steering lock device may not be provided at the outer tube 16. In this case, a configuration in which the opening portion 62 is omitted may be adopted as the outer tube 16. Even when this configuration is adopted, a torsional force may be applied to the outer tube 16 for some reason. In addition, in the case where a configuration in which the opening portion 62 is omitted is adopted as the outer tube 16, as Figure 8 As shown in , the elliptical stress relief portion 72a may be provided to protrude to both sides of the portion of the second slit 72 up to the stress relief portion 72a. In this case, as Fig. 9 As shown in , the elliptical stress relaxation portion 72a and the main portion of the second slit 72 may be continuous with a smooth curve. Even in this case, the same effects as those of the above-described embodiment can be obtained.

[0066] An opening portion for inserting another additional member such as a wire harness may be provided at a position in the outer tube 16 near the second slit 72 instead of the opening portion 62 for inserting the locking member 64 .

[0067] The contour shape of the stress relaxation portion 72 a is not limited to the elliptical shape. The contour shape of the stress relaxation portion 72 a may be set to include an elliptical arc-shaped portion whose major axis direction is a direction intersecting with the second slit 72 .

Claims

1. A steering column device (1), the steering column device (1) rotatably supporting a steering shaft (2), the steering column device (1) comprising: a cylindrical inner tube (17); and a cylindrical outer tube (16) fixed to the inner tube (17) by being externally fitted to slide in the axial direction of the inner tube (17) and elastically reduced in diameter, The outer tube (16) is configured to have a first slit (71) and a second slit (72) to reduce the diameter, the first slit (71) extending in the axial direction of the outer tube (16), the second slit (72) being continuous with the first slit (71) and extending in a direction intersecting with the first slit (71), A stress relief portion (72a) is provided at an end portion of the second slit (72) on the side opposite to the first slit (71), the stress relief portion (72a) opening to have a width longer than a width of the second slit (72) up to the end portion, and The contour shape of the stress relaxation portion (72a) is set to include an elliptical arc portion, the major axis direction of the elliptical arc portion is a direction intersecting with the second slit (72), An opening portion (62) for inserting an additional component is provided in the outer tube (16), the opening portion (62) being located at a distance from the stress relaxation portion (72a) in the axial direction of the outer tube (16), and the opening portion (62) is configured to be separated from the second slit (72) and overlap with the second slit (72) in the axial direction of the outer tube (16), The stress relaxation portion (72a) extends in the axial direction of the outer tube (16) toward a side opposite to the opening portion (62).

2. The steering column device (1) according to claim 1, characterized in that The additional component is a locking member that engages with a portion of the steering shaft (2) and restricts rotation of the steering shaft (2).

3. The steering column device (1) according to claim 1 or 2, characterized in that The stress relaxation portion (72a) and a portion of the second slit (72) up to the stress relaxation portion (72a) are smoothly continuous.

4. The steering column device (1) according to claim 1 or 2, characterized in that: The outline shape of the stress relaxation portion (72a) is elliptical.

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