The disclosure of Japanese Patent Application No. 2018-084450 filed on Apr. 25, 2018 including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
The invention relates to a steering column device for supporting a steering shaft of a vehicle so that the steering shaft is rotatable.
A steering column device for supporting a steering shaft so that the steering shaft is rotatable is installed in a vehicle (see Japanese Patent Application Publication No. 2009-6847 (JP 2009-6847 A), for example). The steering column device has an outer tube, an inner tube, a tubular retainer, and a fastening mechanism. The inner tube is disposed in the outer tube so as to be movable in an axial direction. The retainer is held between the outer tube and the inner tube. A part of the outer tube is deformed radially inward so that the outer tube is fixed to the inner tube by the fastening mechanism.
The steering shaft is rotatably supported inside the outer tube and inside the inner tube. A steering wheel is attached to an end portion of the steering shaft. When adjusting a telescopic position of the steering wheel, the outer tube is moved in the axial direction with respect to the inner tube, after the fixation of the outer tube to the inner tube by the fastening mechanism is released.
However, with the steering column device according to the related art described above, retaining force and a contact surface tend to vary depending on the telescopic position of the steering wheel when the outer tube is fixed to the inner tube by the fastening mechanism.
An object of the invention is to provide a steering column device that is able to suppress variations in retaining force and a contact surface when regulating relative movement of an outer tube and an inner tube with a fastening mechanism.
According to an aspect of the invention, in a steering column device for supporting a steering shaft so that the steering shaft of a vehicle is rotatable, the steering column device includes: an outer tube that extends along an axial direction, in which a first part and a second part that has a lower rigidity than the first part are formed along a circumferential direction around the axial direction; an inner tube that is disposed in the outer tube and that is moveable in the axial direction with respect to the outer tube; a tubular retainer that is disposed between the outer tube and the inner tube; and a fastening mechanism for regulating relative movement of the outer tube and the inner tube in the axial direction by deforming at least the second part of the outer tube radially inward. At least three protruding portions are formed on any one of an inner peripheral surface of the outer tube, an outer peripheral surface of the retainer, an inner peripheral surface of the retainer, and an outer peripheral surface of the inner tube, the at least three protruding portions disposed at intervals in the circumferential direction and extending along the axial direction. The at least three protruding portions include: a first protruding portion and a second protruding portion that are disposed so that a midpoint between the first protruding portion and the second protruding portion in the circumferential direction is offset to the first part side from a vertical line, in a section orthogonal to the axial direction; and a third protruding portion disposed in a region of the second part.
The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:
An embodiment of a steering column device according to the invention will be described with reference to the drawings. The embodiments described below indicate examples that are inclusive or specific. Values, shapes, materials, components, layouts and connection forms of the components, steps, order of the steps etc. are exemplary and do not to limit the invention. Among the components of the following embodiment, the components that are not indicated in the independent claim that indicates the highest concept are described as optional components.
The drawings are schematic drawings subjected to emphasis, omission, and adjustment of a ratio, and thus may be different from the actual shape, positional relationship, and ratio.
The configuration of a steering column device 2 according to the embodiment will be described with reference to
The steering column device 2 is installed in a vehicle that has a telescopic mechanism and is a device for supporting a steering shaft 4 (see
As illustrated in
As illustrated in
As illustrated in
The outer tube 8 is supported so as to be movable in the axial direction with respect to the bracket 6, via the fastening mechanism 12. As illustrated in
As illustrated in
As illustrated in
As illustrated in
When the telescopic position of the steering wheel is adjusted, the steering shaft 4 moves (extends and retracts) in the axial direction with respect to the inner tube 10. Thus, the outer tube 8 moves with the steering shaft 4 in the axial direction with respect to the inner tube 10. When the steering wheel is moved to a telescopic position farthest from a driver (hereinafter also referred to as a “telescopic short position”), the outer tube 8 moves in a direction indicated by an arrow 32 in
The fastening mechanism 12 is a clamp mechanism for regulating relative movement of the outer tube 8 and the inner tube 10 in the axial direction. As illustrated in
As illustrated in
The coupling member 40 is fixed to the bracket 6. The coupling member 40 couples upper end portions of the plate members 36, 38. The support bracket 42 is fixed to an outer peripheral surface of the high rigidity portion 20 of the outer tube 8 by welding etc. and is fixed to the support member 33 by welding etc. The support bracket 44 is fixed to an outer peripheral surface of the low rigidity portion 22 of the outer tube 8 by welding etc. and is fixed to the support member 35 by welding etc.
The lever member 46 includes a screw shaft portion 56 and an operation portion 58 provided at a base end portion of the screw shaft portion 56. The screw shaft portion 56 is inserted in the through hole 48 of the plate member 36, the elongated hole 37 of the support member 33, the elongated hole 39 of the support member 35, and the through hole 50 of the plate member 38. The base end portion of the screw shaft portion 56 is inserted in the fastening member 52. The rotary cam 60 cam-engaged with the fastening member 52 is fixed to the base end portion of the screw shaft portion 56. A nut 62 is screwed to a distal end of the screw shaft portion 56. A bearing portion 64 is disposed between the nut 62 and the plate member 38 so as to support the screw shaft portion 56 so that the screw shaft portion 56 is rotatable.
When the driver manually rotates the operation portion 58 in a locking direction (direction indicated by an arrow 66 in
In contrast, when the telescopic position of the steering wheel is adjusted, the driver manually rotates the operation portion 58 in the releasing direction (direction indicated by an arrow 68 in
The retainer 14 is for suppressing backlash of the steering wheel. As illustrated in
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As illustrated in
Here, a method of setting the positions of the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 with respect to the outer tube 8 will be described. As illustrated in
Thus, in the section orthogonal to the axial direction, on a pressing side (side close to the support brackets 42, 44), force is applied from the outer tube 8 to the inner tube 10 in a prescribed region (region in
In contrast, on a receiving side (side away from the support brackets 42, 44), it is preferable that force from the outer tube 8 be received by at least two positions, taking into consideration the variation of the contact range. Thus, in the section orthogonal to the axial direction, the first protruding portion 78 and the second protruding portion 80 are disposed so that the midpoint 86 therebetween in the circumferential direction is offset to the high rigidity portion 20 side from the vertical line 30. Therefore, the force from the outer tube 8 is able to be effectively received by the first protruding portion 78 and the second protruding portion 80.
In the steering column device 2 of the embodiment, the following advantageous effects are obtained. When the telescopic position of the steering wheel is changed to the telescopic short position, the telescopic neutral position, and the telescopic long position, retaining force and the contact surface when regulating the relative movement of the outer tube 8 and the inner tube 10 in the axial direction is changed. This is because rigidity of the outer tube 8 is not constant in the axial direction. Thus, even if fastening force by the fastening mechanism 12 is constant, the amount of radially inward deformation of the outer tube 8 varies depending on the telescopic position. The contact position between the retainer 14 with respect to the inner tube 10 is thus changed. Since the high rigidity portion 20 and the low rigidity portion 22 are formed in the outer tube 8, rigidity of the outer tube 8 is not constant along the circumferential direction. If a retainer in which the protruding portion is not formed on the outer peripheral surface is used, retaining force and the contact surface vary when the relative movement of the outer tube 8 and the inner tube 10 in the axial direction is regulated by the fastening mechanism 12, depending on the telescopic position of the steering wheel.
In the steering column device 2 of the embodiment, as described above, the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 are formed on the outer peripheral surface of the retainer 14. Suppose the telescopic position of the steering wheel is changed to the telescopic short position, the telescopic neutral position, and the telescopic long position. Even in such a case, only the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 of the outer peripheral surface of the retainer 14 are constantly in contact with the inner peripheral surface of the outer tube 8, when the relative movement of the outer tube 8 and the inner tube 10 in the axial direction is regulated by the fastening mechanism 12. As described above, in the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84, the force from the outer tube 8 is able to be effectively received. Thus, it is possible to suppress variations in retaining force and the contact surface when the relative movement of the outer tube 8 and the inner tube 10 in the axial direction is regulated by the fastening mechanism 12.
Weld beads may be formed in the outer tube 8. However, when the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 are formed on the outer peripheral surface of the retainer 14, it is possible to suppress variations in retaining force and the contact surface caused by the weld beads.
Here, in order to confirm the advantageous effects described above with reference to
As the embodiment, simulation was performed to obtain the pressure on the outer peripheral surface of the inner tube 10 when the steering wheel was disposed at the telescopic short position, the telescopic neutral position, and the telescopic long position using the retainer 14 of the embodiment. Here, the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 are formed on the outer peripheral surface of the retainer 14. The axial tension was 2500 N.
As a comparative example, simulation was performed to obtain the pressure on the outer peripheral surface of the inner tube when the steering wheel was disposed at the telescopic short position, the telescopic neutral position, and the telescopic long position using a retainer in which a protruding portion is not formed on an outer peripheral surface. The axial tension was 2500 N.
The results of the simulations of the embodiment and the comparative example are as illustrated in
In contrast, as illustrated in
It should be noted that the invention is not limited to the above-described embodiment. For example, another embodiment realized by combining the components or excluding a number of the components described in the description may be applied as the embodiment of the invention. Modifications that can be made by those skilled in the art without departing from the meanings of the expressions in the claims are included in the invention.
In the embodiment, the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 are formed on the outer peripheral surface of the retainer 14. However, the configuration is not limited to this. The first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 may be formed on any one of the inner peripheral surface of the outer tube 8, the inner peripheral surface of the retainer 14, and the outer peripheral surface of the inner tube 10, for example.
In the embodiment described above, the high rigidity portion 20 and the low rigidity portion 22 are formed by forming the slit 24 in the outer tube 8. However, the configuration is not limited to this. The high rigidity portion 20 and the low rigidity portion 22 may be formed in the outer tube 8 by changing a thickness of the outer tube 8 along the circumferential direction, for example.
In the embodiment described above, the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 continuously extend along the axial direction from one end portion to the other end portion of the retainer 14. However, the configuration is not limited to this. The first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 may be disposed at intervals (intermittently) along the axial direction, for example.
In the embodiment described above, the first protruding portion 78, the second protruding portion 80, the third protruding portion 82, and the fourth protruding portion 84 are formed on the outer peripheral surface of the retainer 14. However, the fourth protruding portion 84 may be omitted. That is, at least the first protruding portion 78, the second protruding portion 80, and the third protruding portion 82 may be formed on the outer peripheral surface of the retainer 14.
The steering column device according to the invention is able to be applied to vehicles that have a telescopic mechanism, for example.
With the steering column device according to an aspect of the invention, it is possible to reduce variations in retaining force and the contact surface when the relative movement of the outer tube and the inner tube is regulated by the fastening mechanism.
Number | Date | Country | Kind |
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2018-084450 | Apr 2018 | JP | national |