Steering column and steering device

Abstract

To provide a steering column making it easy to ensure the flexural rigidity of an inter column without imposing an adverse effect on an impact absorption characteristic at a time when a secondary collision occurs.SOLUTION: A steering column 3 includes: an outer column 6 having a front small-diameter cylindrical section 8 that is a slide contact cylindrical part; and an inner column 7 having a portion in an axial direction incorporated in the front small-diameter cylindrical section 8. The inner column 7 includes: first projections 15 that project outward in a radial direction and extend in an axial direction from a plurality of points which are mutually separated in a circumferential direction of an outer peripheral surface; and second projections 16 that project outward in the radial direction and extend in the axial direction from points separated from the first projections 15 on the outer peripheral surface. The outer peripheral surface of the inner column 7 comes into contact with an inner peripheral surface of the front small-diameter cylindrical section 8 with an interference only at respective apices of the first projections 15. The second projections 16 do not come into contact with the inner peripheral surface of the front small-diameter cylindrical section 8 with the interference.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a steering column having a function of absorbing an impact load during a secondary collision, and a steering device including the steering column. [Background technology]

[0002] FIG. 29 shows an example of a steering device for an automobile. In the steering device 100, a steering wheel 101 operated by a driver is attached to the rear end of a steering shaft 102. The steering shaft 102 is rotatably supported inside a cylindrical steering column 103 supported on a vehicle body. The rotational motion of the steering wheel 101 is transmitted to a pinion shaft 107 constituting a steering gear unit 106 via the steering shaft 102, a universal joint 104a, an intermediate shaft 105, and another universal joint 104b. The rotational motion of the pinion shaft 107 is converted into a linear motion of a rack shaft (not shown) constituting the steering gear unit 106. As a result, a pair of tie rods 108 are pushed and pulled, and a steering angle according to the amount of operation of the steering wheel 101 is applied to a pair of left and right steered wheels.

[0003] It should be noted that the front-rear direction, width direction, and up-down direction of the steering device refer to the front-rear direction, width direction, and up-down direction of the vehicle body to which the steering device is attached.

[0004] 30 to 32 show a more specific structure of the steering device described in JP 2013-136385 A. The steering device 100a has a function of absorbing an impact load at the time of a secondary collision accompanying a vehicle collision accident.

[0005] The steering column 103a includes a cylindrical inner column 109 disposed on the front side, and a cylindrical outer column 110 disposed on the rear side. The rear side of the inner column 109 is press-fitted into the front side of the outer column 110, i.e., by interference fitting. The inner column 109 has protrusions 111 that protrude radially outward and extend in the axial direction at four equally spaced locations on the outer circumferential surface of the rear side. The outer circumferential surface of the inner column 109 is in contact with the inner circumferential surface of the outer column 110 only at the tops of the protrusions 111 with a tightening margin. The inner column 109 and the outer column 110 have the same thickness dimension, and each has sufficiently high rigidity.

[0006] The inner column 109 is supported so as not to be displaced forward relative to the vehicle body not only under normal circumstances but also in the event of a secondary collision. For this reason, the front end of the inner column 109 is coupled and fixed to the rear end of a gear housing 113 constituting an electric assist device 112 supported on the vehicle body. The axially intermediate portion of the outer column 110 is supported via a vehicle body side bracket 114 attached to the vehicle body or the like so as to be capable of being displaced forward due to the impact of a secondary collision.

[0007] In the event of a collision accident, the impact load at the time of the secondary collision displaces the steering wheel 101 (see FIG. 29), the rear shaft that constitutes the rear part of the steering shaft 102a, and the outer column 110 forward relative to the inner column 109. Then, at this time, the impact load at the time of the secondary collision is absorbed based on the outer circumferential surface of the inner column 109 and the inner circumferential surface of the outer column 110 sliding in the axial direction.

[0008] In particular, in the above-described steering device 100a, the points of contact of the outer circumferential surface of the inner column 109 with the inner circumferential surface of the outer column 110 are limited to the respective apexes of the protrusions 111. That is to say, during a secondary collision, of the outer circumferential surface of the inner column 109, only the respective apexes of the protrusions 111 slide in the axial direction against the inner circumferential surface of the outer column 110. For this reason, during a secondary collision, the outer circumferential surface of the inner column 109 and the inner circumferential surface of the outer column 110 can be caused to slide stably in the axial direction, and the impact load absorption performance can be stabilized. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2013-136385 A Summary of the Invention [Problem to be solved by the invention]

[0010] The conventional structure shown in FIGS. 30 to 32 has room for improvement in the following respects.

[0011] That is, when a secondary collision occurs, the direction of the impact load applied to the steering wheel by the driver M may not coincide with the axial direction of the steering column (see FIG. 1 described later). In such a case, in the above-mentioned conventional structure, a large bending load acts on the inner column 109, based on the positional relationship between the location where the impact load is applied to the steering wheel 101 by the driver M and the fixed location of the steering device 100a to the vehicle body, and the outer column 110 is displaced axially forward. At this time, it is undesirable for bending deformation to occur in the inner column 109.

[0012] In this regard, the protrusions 111 provided on the inner column 109 also function as reinforcing ribs that improve the bending rigidity of the inner column 109. For this reason, it is conceivable to increase the number and range of formation of the protrusions 111 in order to prevent bending deformation of the inner column 109 when the outer column 110 is displaced axially forward.

[0013] However, in order to obtain a desired shock absorbing characteristic in the event of a secondary collision, there are cases in which the formation range and number of the protrusions 111 cannot be changed.

[0014] An object of the present invention is to provide a steering column and a steering device that can easily ensure the bending rigidity of the inner column without affecting the impact absorption characteristics in the event of a secondary collision. [Means for solving the problem]

[0015] A steering column according to one aspect of the present invention includes an outer column having a sliding contact cylindrical portion, and an inner column having an axial portion disposed inside the sliding contact cylindrical portion. The inner column has first protrusions that protrude radially outward and extend in the axial direction at multiple circumferentially spaced locations on the outer circumferential surface, and second protrusions that protrude radially outward and extend in the axial direction at locations on the outer circumferential surface separated from the first protrusions. The outer peripheral surface of the inner column comes into contact with the inner peripheral surface of the sliding cylindrical portion only at the tops of the first protrusions, with a tightening margin, and the second protrusions do not come into contact with the inner peripheral surface of the sliding cylindrical portion with a tightening margin. In other words, the second protrusions do not come into contact with the inner peripheral surface of the sliding cylindrical portion, regardless of whether a secondary collision occurs before or after, or even if they come into contact with the inner peripheral surface of the sliding cylindrical portion, they do so without a tightening margin.

[0016] In a steering column according to one aspect of the present invention, the second protrusion is disposed at a position protruding in the axial direction from the inside of the outer column.

[0017] In a steering column according to one embodiment of the present invention, the location deviated from the first protrusion is the same circumferential location as the first protrusion, and is a location deviated from the first protrusion in the axial direction.

[0018] In a steering column according to one aspect of the present invention, the portion deviated from the first protrusion is a portion deviated from the first protrusion in the circumferential direction.

[0019] In a steering column according to one aspect of the present invention, the rigidity in the radial direction of the sliding contact cylindrical portion is lower than the rigidity in the radial direction of a portion of the inner column that is disposed inside the sliding contact cylindrical portion.

[0020] In a steering column according to one aspect of the present invention, the thickness dimension of the sliding contact cylindrical portion is smaller than the thickness dimension of the portion of the inner column that is disposed inside the sliding contact cylindrical portion.

[0021] In a steering column according to one aspect of the present invention, the sliding contact tube portion is formed in a cylindrical shape.

[0022] A steering device of one embodiment of the present invention includes a steering column, which is the steering column of the present invention, and the inner column is disposed in front of the outer column and is prevented from displacing forward relative to the vehicle body. Effect of the Invention

[0023] According to the steering column and steering device of the present invention, it is easy to ensure the bending rigidity of the inner column without affecting the impact absorption characteristics in the event of a secondary collision. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a side view of a steering device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, with some parts omitted. [Diagram 3]FIG. 3 is a perspective view of the steering column of the first example as viewed from above. [Figure 4] FIG. 4 is a side view of the steering column of the first example. [Diagram 5] FIG. 5 is a view seen from the right side of FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line BB of FIG. [Figure 7] 7 is a cross-sectional view similar to FIG. 6, showing a state in which the outer column has been displaced slightly forward relative to the inner column from the state shown in FIG. [Figure 8] FIG. 8(a) is a cross-sectional view taken along line CC in FIG. 6 and a cross-sectional view taken along line DD in FIG. 7 relating to the outer column and the inner column, and FIG. 8(b) is an enlarged view of a portion E in FIG. 8(a). [Figure 9] FIG. 9(a) is a cross-sectional view taken along line FF in FIG. 7 relating to the outer column and the inner column, and FIG. 9(b) is an enlarged view of part G in FIG. 9(a). [Figure 10] FIG. 10 is a cross-sectional view taken along line HH of FIG. [Figure 11] FIG. 11 is an enlarged view of part I in FIG. [Figure 12] FIG. 12 is a perspective view of the inner column of the first example as viewed from above. [Figure 13] FIG. 13 is a diagram showing the correlation between the interference λ of the first protrusion with respect to the inner circumferential surface of the outer column and the sliding resistance (press-fit load F) of the inner column with respect to the outer column, for the structure of the first example and the structure of the comparative example. [Figure 14] FIG. 14 is a diagram corresponding to FIG. 4 and related to a second embodiment of the present invention. [Figure 15] FIG. 15 is a view corresponding to FIG. 6 and related to the second example. [Figure 16] FIG. 16 is a diagram corresponding to FIG. 12 and related to the second example. [Figure 17] FIG. 17 is a diagram corresponding to FIG. 4 and related to a third embodiment of the present invention. [Figure 18] FIG. 18 is a diagram corresponding to FIG. 6 and related to the third example. [Figure 19] FIG. 19 is a cross-sectional view taken along line JJ of FIG. [Figure 20] FIG. 20 is a diagram corresponding to FIG. 12 and related to the third example. [Figure 21] FIG. 21 is a diagram corresponding to FIG. 4 and related to a fourth embodiment of the present invention. [Figure 22] FIG. 22 is a diagram corresponding to FIG. 6 and related to the fourth example. [Figure 23] FIG. 23 is a cross-sectional view taken along line KK of FIG. [Figure 24] FIG. 24 is a diagram corresponding to FIG. 12 and related to the fourth example. [Diagram 25] FIG. 25 is a view corresponding to FIG. 6 and relating to a first reference example related to the present invention. [Figure 26] FIG. 26 is a diagram relating to the first reference example and corresponds to FIG. [Figure 27] FIG. 27 is a view corresponding to FIG. 6 and relating to a second reference example related to the present invention. [Figure 28] FIG. 28 is a diagram relating to the second reference example and corresponds to FIG. [Figure 29] FIG. 29 is a perspective view showing an example of a conventional structure of a steering device. [Diagram 30] FIG. 30 is a side view showing an example of a more specific structure of the steering device. [Diagram 31] FIG. 31 is a cross-sectional view taken along the line LL in FIG. 30, with some parts omitted. [Diagram 32] FIG. 32 is a cross-sectional view similar to FIG. 31, showing only the inner column and the outer column. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] [First Example of Implementation] A first embodiment of the present invention will be described with reference to FIGS. 1 to 13. FIG.

[0026] As shown in FIGS. 1 and 2, a steering device 1 of this embodiment includes a steering shaft 2, a steering column 3, a vehicle body side bracket 4, and a clamp mechanism 5.

[0027] The front-rear direction, width direction, and up-down direction of the steering device 1 are the front-rear direction, width direction, and up-down direction of the vehicle body to which the steering device is attached. The front side of the steering device 1 is the left side in FIG. 1, and the rear side is the right side in FIG. 1.

[0028] The steering shaft 2 is supported rotatably inside the steering column 3. A steering wheel 44 operated by the driver M is attached to the rear end of the steering shaft 2. The vehicle body bracket 4 supports an axially intermediate portion of the steering column 3 relative to the vehicle body when attached to the vehicle body. In order to make it possible to adjust the height position of the steering wheel 44, the clamp mechanism 5 is switchable between an unlocked state that allows the steering column 3 to be displaced up and down relative to the vehicle body bracket 4, and a locked state that prevents the steering column 3 from being displaced up and down relative to the vehicle body bracket 4.

[0029] The steering column 3 includes an outer column 6 having a sliding cylindrical portion, and an inner column 7, part of which is axially disposed inside the sliding cylindrical portion. In this example, the inner column 7 is disposed in front of the outer column 6, and is prevented from displacing forward with respect to the vehicle body. However, when implementing the present invention, a configuration can also be employed in which the outer column is disposed in front of the inner column, and the outer column is prevented from displacing forward with respect to the vehicle body.

[0030] In this example, each of the outer column 6 and the inner column 7 is a substantially cylindrical member made of a metal such as steel or an aluminum alloy. In this example, each of the outer column 6 and the inner column 7 is manufactured by a predetermined manufacturing method including a process of changing the inner diameter and the outer diameter of a portion of the axial direction of a blank tube such as a drawn tube by performing plastic processing such as hydroforming or drawing on the blank tube, which is an intermediate material. Note that when carrying out the present invention, each of the outer column 6 and the inner column 7 can also be manufactured by other manufacturing methods such as casting. In this example, the thickness dimension of the outer column 6 is generally constant except for the rear end portion (bearing holding portion 13), and the thickness dimension of the inner column 7 is generally constant.

[0031] The sliding contact cylindrical portion of the outer column 6 is a cylindrical portion on the inside of which a portion of the inner column 7 in the axial direction is disposed, and on whose inner circumferential surface the apex of a first protrusion 15 provided on a portion of the inner column 7 in the axial direction comes into contact with a state of interference. In this example, the outer column 6 is equipped with a front small diameter cylindrical portion 8, a large diameter cylindrical portion 9, a rear small diameter cylindrical portion 10, a front connecting portion 11, and a rear connecting portion 12, which are sliding contact cylindrical portions, each of which is disposed coaxially. The front small diameter cylindrical portion 8 is configured in a cylindrical shape. The large diameter cylindrical portion 9 is configured in a cylindrical shape, and is located rearward of the front small diameter cylindrical portion 8. The rear small diameter cylindrical portion 10 is configured in a cylindrical shape, and is located rearward of the large diameter cylindrical portion 9. The inner diameter of the large diameter cylindrical portion 9 is larger than the inner diameters of the front small diameter cylindrical portion 8 and the rear small diameter cylindrical portion 10. The front connecting portion 11 connects the front end of the large diameter cylindrical portion 9 and the rear end of the front small diameter cylindrical portion 8, and is configured in a conical cylindrical shape with an inner diameter that decreases toward the front. The rear connecting portion 12 connects the rear end of the large diameter cylindrical portion 9 and the front end of the rear small diameter cylindrical portion 10, and is configured in a conical cylindrical shape with an inner diameter that decreases toward the rear.

[0032] The rear small diameter cylindrical portion 10 has a bearing holder 13 in its rear half. The inner diameter of the bearing holder 13 is larger than the inner diameter of the front half of the rear small diameter cylindrical portion 10. Therefore, the thickness of the bearing holder 13 is smaller than the thickness of the front half of the rear small diameter cylindrical portion 10.

[0033] The large diameter cylindrical portion 9 has a key lock hole 14 for inserting a lock pin of a steering lock mechanism at one circumferential location in an axially intermediate portion.

[0034] In this example, the inner column 7 includes a large diameter cylindrical portion 17, a small diameter cylindrical portion 18, and a connecting portion 19, which are arranged coaxially. The large diameter cylindrical portion 17 is configured in a cylindrical shape. The small diameter cylindrical portion 18 is configured in a cylindrical shape and is located forward of the large diameter cylindrical portion 17. The outer diameter of the small diameter cylindrical portion 18 is smaller than the outer diameter of the large diameter cylindrical portion 17. The connecting portion 19 connects the front end portion of the large diameter cylindrical portion 17 and the rear end portion of the small diameter cylindrical portion 18, and is configured in a conical cylindrical shape whose outer diameter decreases toward the front.

[0035] The inner column 7 has first protrusions 15 that protrude radially outward and extend in the axial direction at multiple circumferentially spaced locations on the outer circumferential surface. Here, the multiple circumferentially spaced locations are at least three locations in the circumferential direction, and do not have to be equally spaced in the circumferential direction. The range of axial extension is the maximum extension range of the outer column 6 of the inner column 7 in the assembled state of the steering column 3 before the occurrence of a secondary collision. Sliding contact It is sufficient that the range includes at least a part of the axial range disposed inside the cylindrical portion (front small diameter cylindrical portion 8).

[0036] In this example, the first ridges 15 are disposed at four locations that are equally spaced circumferentially on the outer circumferential surface of the large diameter cylindrical portion 17. More specifically, each of the first ridges 15 exists in a continuous axial range that corresponds to the entire length of the axial range of the large diameter cylindrical portion 17 that fits with the front small diameter cylindrical portion 8 of the outer column 6, specifically, the rear end and middle portion of the large diameter cylindrical portion 17 in the axial direction, in the assembled state of the steering column 3 before the occurrence of a secondary collision.

[0037] In this example, the circumferential positions of the first protrusions 15 in the used state are set to a total of four positions, including two positions shifted 45° on both circumferential sides from the upper end and two positions shifted 45° on both circumferential sides from the lower end, as shown in Figures 2, 5, and 8. The circumferential positions of the first protrusions 15 in the used state may be different from the illustrated example. For example, the circumferential positions of the first protrusions 15 in the used state may be set to a total of four positions, including two positions rotated 45° from the circumferential positions in this example, i.e., two positions at the upper end and lower end, and two positions at both widthwise ends.

[0038] In this example, each of the first ridges 15 is formed by plastically deforming a part of the large diameter cylindrical portion 17 radially outward. Therefore, a concave groove extending in the axial direction is present on the back surface of each of the first ridges 15. The radially outer surface of the first ridges 15 has a convex arc-shaped cross section as shown in Figures 8(a) and 8(b). In a free state, the diameter of a circumscribing circle of the first ridges 15 centered on the central axis of the large diameter cylindrical portion 17 is slightly larger than the inner diameter of the front small diameter cylindrical portion 8.

[0039] The inner column 7 has a second ridge 16 that protrudes radially outward and extends in the axial direction at a location on the outer circumferential surface that is separated from the first ridge 15. Here, the location that is separated from the first ridge 15 is a location that is separated from the first ridge 15 in the axial and / or circumferential directions. The range that extends in the axial direction refers to only at least a part of the axial range of the inner column 7 that is located inside the fitting cylindrical portion (front small diameter cylindrical portion 8) of the outer column 6 in the assembled state of the steering column 3 before the occurrence of a secondary collision, or only the part of the axial range that protrudes in the axial direction from the inside of the fitting cylindrical portion. (exposure) The number of second ridges 16 may be at least a part of the axial ranges mentioned above, or may be an axial range spanning these axial ranges. The number of second ridges 16 can be determined arbitrarily, and may be one or more. When adopting a configuration in which second ridges 16 are provided at multiple locations spaced apart in the circumferential direction, the multiple locations spaced apart in the circumferential direction do not have to be equally spaced apart in the circumferential direction.

[0040] In this example, the second ribs 16 are provided in the same number as the first ribs 15, that is, four. Each of the second ribs 16 is disposed in the same circumferential position as the first ribs 15, but is disposed in a position offset in the axial direction from the first ribs 15. Specifically, each of the second ribs 16 is disposed in a position adjacent to the front side of the first ribs 15. Each of the second ribs 16 is present in an axial range of the large diameter cylindrical portion 17 that protrudes forward from the front small diameter cylindrical portion 8, specifically, in an axial range corresponding to the front end portion of the large diameter cylindrical portion 17 in the axial direction, in the assembled state of the steering column 3 before the occurrence of a secondary collision.

[0041] In this example, each of the second ridges 16 is formed by plastically deforming a part of the large-diameter cylindrical portion 17 radially outward. Therefore, a concave groove extending in the axial direction is present on the back surface of each of the second ridges 16. The radially outer surface of the second ridges 16 has a convex arc-shaped cross section as shown in Figs. 9(a) and 9(b). In the free state, the radial height of the second ridges 16 is smaller than the radial height of the first ridges 15. In the free state, the diameter of a circumscribing circle of the second ridges 16 centered on the central axis of the large-diameter cylindrical portion 17 is slightly smaller than the inner diameter of the front small-diameter cylindrical portion 8.

[0042] The outer peripheral surface of the inner column 7 comes into contact with the inner peripheral surface of the front small diameter cylindrical portion 8, which is the sliding cylindrical portion of the outer column 6, only at the tops of the first protrusions 15, with an interference therebetween.

[0043] 6, 10, and 11, in this example, the axial intermediate portion and rear portion of the large diameter cylindrical portion 17 that is the rear portion of the inner column 7 are disposed inside the front small diameter cylindrical portion 8 that is the front portion of the outer column 6, and specifically, are fitted within by press fitting. In this state, only the tops of the first protrusions 15 of the outer peripheral surface of the large diameter cylindrical portion 17 contact the inner peripheral surface of the front small diameter cylindrical portion 8 with a tightening margin.

[0044] Furthermore, in this state, the axially front portion of the large diameter cylindrical portion 17 having the second protrusion 16 protrudes forward of the front small diameter cylindrical portion 8, as shown in Figures 3, 4, 6, 10, and 11. Even if the outer column 6 is displaced forward relative to the inner column 7 during a secondary collision and the axially front portion of the large diameter cylindrical portion 17 having the second protrusion 16 enters the inside of the front small diameter cylindrical portion 8 as shown in Figure 7, the tops of the second protrusions 16 do not come into contact with the inner circumferential surface of the front small diameter cylindrical portion 8, as shown in Figures 9(a) and 9(b).

[0045] In this example, the radial rigidity of the front small diameter cylindrical portion 8, which is the sliding cylindrical portion, is lower than the radial rigidity of the large diameter cylindrical portion 17, which is the portion of the inner column 7 that is positioned inside the front small diameter cylindrical portion 8, i.e., the portion that is fitted into the front small diameter cylindrical portion 8.

[0046] For this reason, in this embodiment, the thickness dimension T out The thickness dimension T of the large diameter cylindrical portion 17 in It is smaller than (T out <T in When the present invention is implemented, the thickness dimension T of the front small diameter cylindrical portion 8 is out is the thickness dimension T of the large diameter cylindrical portion 17 in It is preferable that the thickness dimension T of the large diameter cylindrical portion 17 is 50% or less of 90%. in It is more preferable that the range is 60% or more and 80% or less of the above.

[0047] When implementing the present invention, in order to make the radial rigidity of the sliding contact cylindrical portion lower than the radial rigidity of the portion of the inner column that is disposed inside the sliding contact cylindrical portion, it is possible to use a material for the outer column that has a lower radial rigidity than the material of the inner column, or to configure the sliding contact cylindrical portion in a non-circular cylindrical shape, such as a rectangular cylindrical shape. However, in the structure of this example, because the front small diameter cylindrical portion 8, which is the sliding contact cylindrical portion, is configured in a cylindrical shape, the inner column can be manufactured more easily compared to when the sliding contact cylindrical portion is configured in a non-circular cylindrical shape, such as a rectangular cylindrical shape.

[0048] When implementing the present invention, the radial rigidity of the sliding tubular portion can be made equal to the radial rigidity of the portion of the inner column that is disposed inside the sliding tubular portion, or the radial rigidity of the sliding tubular portion can be made higher than the radial rigidity of the portion of the inner column that is disposed inside the sliding tubular portion. out and thickness dimension T in and the structure (T out =T in ) and thickness dimension T out is the thickness dimension T in A structure larger than (T out >T in ) can also be adopted.

[0049] The inner column 7 is supported so as not to be displaced forward relative to the vehicle body not only under normal circumstances but also during a secondary collision. For this purpose, the front end of the inner column 7 is coupled and fixed to the rear end of a gear housing 21 constituting an electric assist device 20 supported on the vehicle body. The electric assist device 20 reduces the force required for the driver M to operate the steering wheel 44 by applying auxiliary power generated by an electric motor 22 as a power source to a steering force transmission path connecting the steering wheel 44 to the steered wheels. In this example, in order to make the height position of the steering wheel 44 adjustable, the gear housing 21 is supported so as to be capable of swinging and displacing about a tilt shaft 23 relative to the vehicle body.

[0050] In this example, the steering column 3 further includes a mounting plate 24 for connecting and fixing the front end of the inner column 7 to the rear end of the gear housing 21. The mounting plate 24 is an annular flat plate member, and is fitted and fixed to the front end of the small diameter cylindrical portion 18 of the inner column 7. The mounting plate 24 has mounting holes 25 at multiple locations (three locations in the illustrated example) spaced apart in the circumferential direction. Meanwhile, the gear housing 21 has screw holes (not shown) at locations of its rear end that match with the respective mounting holes 25 of the mounting plate 24. The front end of the inner column 7 is connected and fixed to the rear end of the gear housing 21 by screwing bolts (not shown) inserted from the rear side into the respective mounting holes 25 of the mounting plate 24 into the screw holes of the gear housing 21.

[0051] In this example, the phase of the circumferential arrangement of the mounting holes 25 provided in the mounting plate 24 is regulated so that the circumferential positions of the multiple first protrusions 15 with respect to the gear housing 21, i.e., the circumferential positions of the multiple first protrusions 15 in an in-use state, are regulated uniquely with the front end of the inner column 7 coupled and fixed to the rear end of the gear housing 21. Specifically, the mounting holes 25 are arranged at uneven intervals in the circumferential direction.

[0052] In this example, the steering column 3 further includes a column-side bracket 26 that is joined and fixed to the outer column 6. The column-side bracket 26 is made of a metal such as steel and has a U-shape. That is, the column-side bracket 26 includes a pair of side plate portions 27 that are arranged parallel to each other and spaced apart in the width direction, and a connecting plate portion 28 that connects the lower ends of the pair of side plate portions 27 to each other. Each of the side plate portions 27 has a circular through hole 29 at a position where the side plate portions 27 are aligned with each other in the width direction. The column-side bracket 26 is joined and fixed to the outer column 6 by welding the upper ends of each of the pair of side plate portions 27 to both sides in the width direction of the front small diameter cylindrical portion 8 of the outer column 6. In this state, the width direction outer side surfaces of each of the pair of side plate portions 27 protrude outward in the width direction beyond the outer circumferential surface of the front small diameter cylindrical portion 8.

[0053] As shown in FIG. 1, the steering shaft 2 includes a front shaft 30 disposed on the front side and a rear shaft 31 disposed on the rear side. The front shaft 30 and the rear shaft 31 are spline-fitted to enable torque transmission and relative displacement in the axial direction.

[0054] The rear shaft 31 is supported by a rolling bearing (not shown) that is fitted and held inside the bearing holding portion 13 with respect to the outer column 6 so as to be rotatable only. At a position on the rear shaft 31 that aligns with the key lock hole 14 of the outer column 6 in the axial direction, a key lock collar (not shown) of the steering lock mechanism is externally fitted and fixed. The rear end portion of the rear shaft 31 protrudes axially from the inside of the outer column 6. The steering wheel 44 is attached to the rear end portion of the rear shaft 31.

[0055] The front shaft 30 is supported by a rolling bearing (not shown) so as to be rotatable only with respect to the inner column 7 and the gear housing 21. The front end portion of the front shaft 30 protrudes axially from the inside of the inner column 7 and is inserted into the inside of the gear housing 21.

[0056] The vehicle body side bracket 4 is made of metal such as steel and includes a mounting plate portion 32 and a pair of support plate portions 33. The mounting plate portion 32 constitutes the upper portion of the vehicle body side bracket 4 and is arranged in the width direction. The mounting plate portion 32 is supported with respect to the vehicle body so as to be able to move forward due to the impact during a secondary collision. The pair of support plate portions 33 are arranged substantially parallel to each other at positions sandwiching the column side bracket 26 from both sides in the width direction. Each of the support plate portions 33 has an upper end portion coupled and fixed to the middle portion in the width direction of the mounting plate portion 32. Each of the support plate portions 33 has a tilt long hole 34 extending in the vertical direction at a position that aligns with each other in the width direction and aligns with the through hole 29 of the column side bracket 26. Each of the tilt long holes 34 has an arc shape centered on the tilt axis 23.

[0057] As shown in FIG. 2, the clamp mechanism 5 includes an adjustment rod 35, an adjustment nut 36, a cam device 37, an adjustment lever 38, and a thrust bearing 39.

[0058] The adjustment rod 35 is inserted through the pair of tilt long holes 34 and the pair of through holes 29 in the width direction. The adjustment rod 35 has a head 40 at its base end (left end in FIG. 2) and a male screw portion 41 at its tip end (right end in FIG. 2). The adjustment nut 36 is screwed onto the male screw portion 41. The cam device 37 is disposed between the head 40 and one of the support plate parts 33 (left side in FIG. 2). The cam device 37 has a driving side cam 42 located on the outside in the width direction and a driven side cam 43 located on the inside in the width direction. The adjustment lever 38 has a base end fixed to the driving side cam 42. The driven side cam 43 is engaged with the tilt long hole 34 of one of the support plate parts 33 so as not to rotate relative to it. When the adjustment lever 38 is swung around the adjustment rod 35 to rotate the driving cam 42 and the driven cam 43 relative to each other, the axial dimension of the cam device 37 increases or decreases based on the mutual pressing of the opposing side surfaces (cam faces) of the driving cam 42 and the driven cam 43. In this example, when the adjustment lever 38 is swung in a predetermined direction, the axial dimension of the cam device 37 decreases, and when the adjustment lever 38 is swung in the opposite direction to the predetermined direction, the axial dimension of the cam device 37 increases. The thrust bearing 39 is disposed between the adjustment nut 36 and the other (right side in FIG. 2) support plate portion 33.

[0059] When adjusting the height position of the steering wheel 44, the clamp mechanism 5 is put into an unlocked state by swinging the adjustment lever 38 in a predetermined direction. That is, when the adjustment lever 38 is swung in a predetermined direction (for example, downward), the axial dimension of the cam device 37 is reduced, and the distance between the driven-side cam 43 and the thrust bearing 39 is increased. As a result, the frictional force acting between the widthwise inner surfaces of the pair of support plate parts 33 and the widthwise outer surfaces of the pair of side plate parts 27 is reduced or lost, resulting in an unlocked state in which the column-side bracket 26 can be displaced relative to the vehicle-body-side bracket 4. In this unlocked state, the height position of the steering wheel 44 can be adjusted within the range in which the adjustment rod 35 can move inside the pair of tilt long holes 34 by swinging and displacing the steering column 3a around the tilt shaft 23.

[0060] After adjusting the height position of the steering wheel 44, the clamp mechanism 5 is locked by swinging the adjustment lever 38 in the opposite direction to the predetermined direction (e.g., upward). That is, when the adjustment lever 38 is swung in the opposite direction to the predetermined direction, the axial dimension of the cam device 37 increases, and the distance between the driven-side cam 43 and the thrust bearing 39 decreases. As a result, the frictional force acting between the widthwise inner surfaces of the pair of support plate portions 33 and the widthwise outer surfaces of the pair of side plate portions 27 increases, resulting in a locked state in which the column-side bracket 26 cannot be displaced relative to the vehicle-body-side bracket 4. By achieving this locked state, the steering wheel 44 is held at the adjusted height position.

[0061] When a car crashes and a secondary collision occurs in which the body of the driver M hits the steering wheel 44, a forward impact load is applied from the steering wheel 44 via the rear shaft 31 to the outer column 6 and the vehicle body side bracket 4. This impact load causes the vehicle body side bracket 4 to separate forward from the vehicle body, and the outer column 6, the rear shaft 31, and the steering wheel 44 are displaced forward relative to the inner column 7 and the front shaft 30. At this time, the impact load at the time of the secondary collision is absorbed based on the axial sliding between the outer peripheral surface of the large diameter cylindrical portion 17 of the inner column 7 and the inner peripheral surface of the front small diameter cylindrical portion 8 of the outer column 6.

[0062] In particular, in this example, the points of contact of the outer circumferential surface of the large diameter cylindrical portion 17 of the inner column 7 with the inner circumferential surface of the front small diameter cylindrical portion 8 of the outer column 6 are limited to the respective apexes of the first protrusions 15. In other words, during a secondary collision, of the outer circumferential surface of the large diameter cylindrical portion 17 of the inner column 7, only the respective apexes of the first protrusions 15 slide in the axial direction against the inner circumferential surface of the front small diameter cylindrical portion 8 of the outer column 6. For this reason, during a secondary collision, the outer circumferential surface of the large diameter cylindrical portion 17 of the inner column 7 and the inner circumferential surface of the front small diameter cylindrical portion 8 of the outer column 6 can be caused to slide stably in the axial direction, and the impact load absorption performance can be stabilized.

[0063] 1, when a secondary collision occurs, the direction of the impact load applied from the driver M to the steering wheel 44 may not coincide with the axial direction of the steering column 3. In such a case, a large bending load acts on the inner column 7, and the outer column 6 is displaced axially forward, based on the positional relationship between the location where the impact load is applied from the driver M to the steering wheel 44 and the fixed location of the steering device 1 with respect to the vehicle body.

[0064] In this regard, in the structure of this example, the first ridge 15 provided on the large diameter cylindrical portion 17 of the inner column 7 also functions as a reinforcing rib for the large diameter cylindrical portion 17. For this reason, it is easy to ensure the bending rigidity of the axial range of the large diameter cylindrical portion 17 in which the first ridge 15 exists, i.e., the rear end and middle portion of the large diameter cylindrical portion 17 in the axial direction.

[0065] Furthermore, the large diameter cylindrical portion 17 of the inner column 7 is provided with a second ridge 16 in addition to the first ridge 15. The second ridge 16 functions as a reinforcing rib for the large diameter cylindrical portion 17. For this reason, in the structure of the present example, compared to a structure provided with only the first ridge 15 of the first and second ridges 15 and 16, it is easier to ensure the bending rigidity of the axial range of the large diameter cylindrical portion 17 in which the second ridge 16 exists, i.e., the axial front end portion of the large diameter cylindrical portion 17. Therefore, according to the structure of the present example, bending deformation of the large diameter cylindrical portion 17 of the inner column 7 can be effectively prevented, and the outer column 6 can be normally displaced axially forward.

[0066] It should be noted that a structure may be considered in which the first rib protrusion 15 is formed at the axial front end of the large diameter cylindrical portion 17 instead of the second rib protrusion 16. In such a structure, the first rib protrusion 15 makes it easier to ensure the bending rigidity of the axial front end of the large diameter cylindrical portion 17. However, in order to obtain the desired shock absorbing characteristics when a secondary collision occurs, there are cases in which the formation range of the first rib protrusion 15 cannot be changed. In such a case, by forming a rib that does not come into contact with the inner circumferential surface of the front small diameter cylindrical portion 8, which is the sliding cylindrical portion, in a state of having a tightening margin, i.e., the second rib protrusion 16, as in the structure of this example, it becomes easy to ensure the bending rigidity of the inner column 7 without affecting the shock absorbing characteristics when a secondary collision occurs.

[0067] Furthermore, in the structure of this example, the thickness dimension T in The thickness dimension T of the front small diameter cylindrical portion 8 of the outer column 6 out Since it is larger than (T in >T out), it is easy to ensure the bending rigidity of the large diameter cylindrical portion 17. Therefore, from this perspective as well, bending deformation of the large diameter cylindrical portion 17 of the inner column 7 can be effectively prevented, allowing the outer column 6 to be normally displaced axially forward.

[0068] Because the steering device 1 of this example absorbs the impact load during a secondary collision based on the axial sliding between the outer peripheral surface of the inner column 7 and the inner peripheral surface of the outer column 6, it is important from the standpoint of adequately protecting the driver M to keep the axial sliding resistance between the inner column 7 and the outer column 6, i.e., the press-fit load F of the outer peripheral surface of the inner column 7 against the inner peripheral surface of the outer column 6, within an appropriate range. In this regard, with the steering device 1 of this example, it is easy to keep the press-fit load F of the outer peripheral surface of the inner column 7 against the inner peripheral surface of the outer column 6 within an appropriate range. The reason for this will be explained below.

[0069] In this example, the rigidity in the radial direction of the front small diameter cylindrical portion 8 of the outer column 6 is intentionally made lower than the rigidity in the radial direction of the large diameter cylindrical portion 17 of the inner column 7. To this end, specifically, the thickness dimension T out The thickness dimension T of the large diameter cylindrical portion 17 in It is smaller than (T out <T in ) In this way, a difference in radial rigidity (spring constant) is intentionally created between the front small diameter cylindrical portion 8 and the large diameter cylindrical portion 17, which fit together, so that the radial rigidity of the front small diameter cylindrical portion 8 is intentionally made lower than the radial rigidity of the large diameter cylindrical portion 17.

[0070] Therefore, in the structure of this embodiment, the thickness dimension T of the front small diameter cylindrical portion 8 is the same as that of the conventional embodiment. out and the thickness dimension T of the large diameter cylindrical portion 17 in The comparative example structure (T in =T out), radial deflection is more likely to occur in the front small diameter cylindrical portion 8 when the outer circumferential surface of the large diameter cylindrical portion 17 is press-fitted into the inner circumferential surface of the front small diameter cylindrical portion 8. As a result, in the structure of this example, with regard to the correlation between the interference λ of the fitting portion between the large diameter cylindrical portion 17 and the front small diameter cylindrical portion 8 and the press-fit load F of the outer circumferential surface of the large diameter cylindrical portion 17 against the inner circumferential surface of the front small diameter cylindrical portion 8, the variation in the press-fit load F relative to the variation in the interference λ can be made smaller than in the structure of the comparative example.

[0071] Fig. 13 is an image diagram that visualizes this point, specifically, a graph showing the correlation between the interference λ of the fitting portion between the front small diameter cylindrical portion 8 and the large diameter cylindrical portion 17 and the press-fit load F of the outer peripheral surface of the large diameter cylindrical portion 17 relative to the inner peripheral surface of the front small diameter cylindrical portion 8. As shown in the graph in Fig. 13, in the structure of this example (solid line α), the press-fit load F changes more gradually with respect to the change in interference λ, compared to the structure of the comparative example (dashed line β). In other words, in the structure of this example, the allowable range of interference λ for keeping the press-fit load F within an appropriate range is wider than in the structure of the comparative example.

[0072] Therefore, in the structure of this example, compared to the structure of the comparative example, there is no need to increase the precision of the outer column 6 and the inner column 7 in order to keep the press-fit load F within the appropriate range. Also, the work of selectively combining the inner column 7 and the outer column 6 in order to keep the press-fit load F within the appropriate range is not necessary, or even if this work becomes necessary, the time required for this work can be shortened. In other words, in the structure of this example, it is easy to keep the press-fit load F within the appropriate range. Therefore, the manufacturing costs of the steering device 1 can be kept low.

[0073] [Second Example of the Implementation Form] A second embodiment of the present invention will be described with reference to FIGS.

[0074] This example is a modification of the first example of the embodiment. In this example, the inner column 7a that constitutes the steering column 3a has a cylindrical shape with a constant diameter over its entire length except for the locations where the first ridge 15 and the second ridge 16 are formed. Accordingly, in this example, each of the second ridges 16 extends to a position closer to the front edge of the inner column 7a than in the case of the first example of the embodiment.

[0075] In the structure of this example, since the diameter dimension of the front portion in the axial direction of the inner column 7a can be made larger than in the case of the first example of the embodiment, the bending rigidity of the front portion can be improved. Since each of the second ridges 16 extends to a position closer to the front edge of the inner column 7a, the bending rigidity of the front portion in the axial direction of the inner column 7a can also be improved in this aspect. Other configurations and effects are the same as those of the first example of the embodiment.

[0076] [Third Example of the Embodiment] The third example of the embodiment of the present invention will be described with reference to FIGS. 17 to 20.

[0077] This example is a modification of the first example of the embodiment. In this example, the second ridge 16 provided on the inner column 7b that constitutes the steering column 3b is arranged at a location circumferentially offset from the first ridge 15. When implementing the present invention, when the second ridge 16 is arranged at a location circumferentially offset from the first ridge 15 as in this example, the number of the second ridges 16, the circumferential position of the second ridges 16 in the range circumferentially offset from the first ridge 15, and the axial range in which the second ridges 16 exist can all be arbitrarily determined. For example, the axial range in which the second ridges 16 exist can be a different axial range in relation to the axial range in which the first ridge 15 exists, or can be at least partially the same axial range.

[0078] In this example, the second ridges 16 are provided in the same number as the first ridges 15, i.e., four. The first ridges 15 and the second ridges 16 are arranged alternately and at equal pitches in the circumferential direction. Each of the second ridges 16 exists in a continuous axial range from the rear edge in the axial direction to a position close to the front edge on the outer circumferential surface of the large diameter cylindrical portion 17. Specifically, the rear end and middle portion of each of the second ridges 16 exist in the same axial range as the first ridges 15, and the front end of each of the second ridges 16 exists in an axial range forward of the first ridges 15. The steering column 3 before the secondary collision occurs b In the assembled state shown in FIG. 1, the front end portion in the axial direction of each of the second protrusions 16 is disposed in a portion protruding forward from the inside of the front small diameter cylindrical portion 8 of the outer column 6. The other configurations and effects are similar to those of the first embodiment.

[0079] [Fourth Example of the Implementation Form] A fourth embodiment of the present invention will be described with reference to FIGS.

[0080] This example is a modified example of the second example of the embodiment. In this example, the second ridges 16 provided on the inner column 7c constituting the steering column 3c are arranged at a position deviated from the first ridges 15 in the circumferential direction. Specifically, the second ridges 16 are provided in the same number as the first ridges 15, that is, four. The first ridges 15 and the second ridges 16 are arranged alternately and at equal pitches in the circumferential direction. Each of the second ridges 16 exists in a continuous axial range from the axial front edge to the intermediate portion on the outer circumferential surface of the inner column 7c. Specifically, the axial front end and intermediate portion of each of the second ridges 16 exist in an axial range forward of the first ridges 15, and the axial rear end exists in the same axial range as the axial front end of the first ridges 15. The steering column 3 before the secondary collision occurs c In the assembled state shown in FIG. 1, the front end portion and the middle portion of each of the second protrusions 16 in the axial direction are disposed in a portion protruding forward from the inside of the front small diameter cylindrical portion 8 of the outer column 6. The other configurations and effects are similar to those of the first and second embodiments.

[0081] [Reference Example 1] A first reference example related to the present invention will be described with reference to Figures 25 and 26. This reference example is a modified example of the first embodiment, and differs from the first example only in that the large diameter cylindrical portion 17 of the inner column 7z1 constituting the steering column 3z1 does not have a second protrusion at the axial front end portion. In the structure of this reference example, the rigidity of the axial front end portion of the large diameter cylindrical portion 17 is reduced by the amount that the second protrusion is not provided, but other functions and effects are similar to those of the first example.

[0082] [Reference Example 2] A second reference example related to the present invention will be described with reference to Figures 27 and 28. This reference example is a modification of the second embodiment, and differs from the second example only in that the second protrusion is not provided on the axial front side of the inner column 7z2 constituting the steering column 3z2, and instead the first protrusion 15 is formed to extend to a position close to the front edge of the inner column 7z2. Other functions and effects are similar to those of the second example.

[0083] In addition, when implementing the present invention, the structures of the above-mentioned embodiments can be appropriately combined within a range that does not cause contradictions. For example, in the structures of the first and second embodiments, a structure in which a second ridge is further added at a position offset from the first ridge 15 in the circumferential direction can be adopted.

[0084] The steering device of the present invention does not include a mechanism for adjusting the height position of the steering wheel. I It can also be applied to a tearing device. [Explanation of symbols]

[0085] 1 Steering device 2 Steering shaft 3, 3a, 3b, 3c, 3z1, 3z2 Steering column 4 Vehicle side bracket 5 Clamping mechanism 6 Outer column 7, 7a, 7b, 7c, 7z1, 7z2 Inner column 8 Front small diameter cylinder 9 Large diameter cylinder 10 Rear small diameter cylinder part 11 Front connection part 12 Rear connection part 13 Bearing holder 14 Key lock hole 15 First ridge 16 Second ridge 17 Large diameter cylinder 18 Small diameter cylinder part 19 Connecting part 20 Electrically assisted device 21 Gear housing 22 Electric motor 23 Tilt axis 24 Mounting plate 25 Mounting hole 26 Column side bracket 27 Side plate part 28 Connecting plate part 29 Through hole 30 Front shaft 31 Rear shaft 32 Mounting plate 33 Support plate part 34 Tilt slot 35 Adjustment rod 36 Adjustment nut 37 Cam device 38 Adjustment lever 39 Thrust bearing 40 head 41 Male thread 42 Drive side cam 43 Driven side cam 44 Steering Wheel 100 Steering device 101 Steering Wheel 102, 102a steering shaft 103, 103a Steering column 104a, 104b Universal joint 105 Intermediate shaft 106 Steering gear unit 107 Pinion shaft 108 Tie rod 109 Innacolumn 110 Outer Column 111 Projection 112 Electrically assisted device 113 Gear housing 114 Body side bracket

Claims

1. an outer column having a sliding contact cylindrical portion; an inner column, a portion of which in the axial direction is disposed inside the sliding contact cylindrical portion, the inner column has a plurality of first protrusions at a plurality of circumferentially separated locations on an outer circumferential surface, each protruding radially outward and extending in an axial direction, and has a second protrusion at a location on the outer circumferential surface separated from the first protrusions, the second protrusion protruding radially outward and extending in the axial direction, an outer circumferential surface of the inner column contacts with an inner circumferential surface of the sliding contact cylindrical portion only at the tops of the first protrusions, and the second protrusions do not contact with the inner circumferential surface of the sliding contact cylindrical portion with an interference, a location where the second protrusion is arranged includes a location that is exposed in the axial direction from an inner side of the outer column and is offset in the axial direction from the first protrusion; Steering column.

2. an outer column having a sliding contact cylindrical portion; an inner column, a portion of which in the axial direction is disposed inside the sliding contact cylindrical portion, the inner column has a plurality of first protrusions at a plurality of circumferentially separated locations on an outer circumferential surface, each protruding radially outward and extending in an axial direction, and has a second protrusion at a location on the outer circumferential surface separated from the first protrusions, the second protrusion protruding radially outward and extending in the axial direction, an outer circumferential surface of the inner column contacts with an inner circumferential surface of the sliding contact cylindrical portion only at the tops of the first protrusions, and the second protrusions do not contact with the inner circumferential surface of the sliding contact cylindrical portion with an interference, the location deviated from the first protrusion is the same circumferential location as the first protrusion and is deviated from the first protrusion in the axial direction; Steering column.

3. an outer column having a sliding contact cylindrical portion; an inner column, a portion of which in the axial direction is disposed inside the sliding contact cylindrical portion, the inner column has a plurality of first protrusions at a plurality of circumferentially separated locations on an outer circumferential surface, each protruding radially outward and extending in an axial direction, and has a second protrusion at a location on the outer circumferential surface separated from the first protrusions, the second protrusion protruding radially outward and extending in the axial direction, an outer circumferential surface of the inner column contacts with an inner circumferential surface of the sliding contact cylindrical portion only at the tops of the first protrusions, and the second protrusions do not contact with the inner circumferential surface of the sliding contact cylindrical portion with an interference, the rigidity in the radial direction of the sliding contact cylindrical portion is lower than the rigidity in the radial direction of a portion of the inner column that is disposed inside the sliding contact cylindrical portion; Steering column.

4. an outer column having a sliding contact cylindrical portion; an inner column, a portion of which in the axial direction is disposed inside the sliding contact cylindrical portion, the inner column has a plurality of first protrusions at a plurality of circumferentially separated locations on an outer circumferential surface, each protruding radially outward and extending in an axial direction, and has a second protrusion at a location on the outer circumferential surface separated from the first protrusions, the second protrusion protruding radially outward and extending in the axial direction, an outer circumferential surface of the inner column contacts with an inner circumferential surface of the sliding contact cylindrical portion only at the tops of the first protrusions, and the second protrusions do not contact with the inner circumferential surface of the sliding contact cylindrical portion with an interference, a thickness dimension of the sliding contact cylindrical portion is smaller than a thickness dimension of a portion of the inner column that is disposed inside the sliding contact cylindrical portion; Steering column.

5. The portion deviated from the first protrusion is a portion deviated from the first protrusion in a circumferential direction. A steering column according to any one of claims 1, 3 and 4.

6. The sliding contact tube portion is configured in a cylindrical shape. A steering column according to any one of claims 1 to 5.

7. A steering device having a steering column, The steering column is a steering column according to any one of claims 1 to 6, The inner column is disposed in front of the outer column and is prevented from being displaced forward with respect to the vehicle body. Steering gear.

Images