JP2014151714A - Impact-absorbing steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact-absorbing steering system capable of suppressing a peak load by securing sufficient impact-absorbing energy.SOLUTION: At a secondary collision, impact-absorbing energy generated by frictional slide between impact-absorbing protrusions 22, 23 and an inner jacket 12 is obtained. A first seal member retained on an inner circumference 11a of an outer jacket 11 seals between both of the jackets 11, 12. A second seal member 26 on an outer circumference 12a of the inner jacket 12 is inserted into the outer jacket 11 in the middle of contraction of a steering column 8 to seal between both of the jackets 11, 12. A sealed space S formed between both of the seal members 24, 26 is contracted accompanying contraction of the steering column 8 to increase inner pressure (air pressure), thereby generating reactive force R against the contraction.

Description

  The present invention relates to an impact absorbing steering apparatus.

  There has been proposed an impact absorbing steering device in which an inner column is composed of an inner cylinder and an outer cylinder, and a sealed space between the inner cylinder and the outer cylinder is filled with a viscous fluid (see, for example, Patent Document 1). ). In Patent Document 1, when a secondary collision occurs, a thin plate (seal part) that closes the discharge port at one end of the sealed space is broken by the rise in pressure of the fluid in the sealed space, so that the fluid is discharged to the outside through the discharge port. The Shock absorption energy is generated by the discharge resistance of the fluid passing through the discharge port.

  On the other hand, an impact-absorbing steering device has been proposed that absorbs an impact by sliding a friction piece provided on the upper column while rubbing against the lower column during a secondary collision (see, for example, Patent Document 2).

JP 2010-12831 A Japanese Patent Laid-Open No. 10-258745

In Patent Document 1, there is a possibility that the shock absorption energy varies due to variations in fluid viscosity caused by temperature changes or the like. In Patent Document 2, there is a possibility that the impact absorption energy varies due to variations in the frictional load of the friction pieces. If the shock absorption energy is insufficient, bottoming may occur and the peak load may be excessive.
Accordingly, an object of the present invention is to provide an impact-absorbing steering device that can secure sufficient impact-absorbing energy and suppress a peak load.

  In order to achieve the above-mentioned object, the invention of claim 1 is directed to an outer jacket (11) and an inner jacket (fittingly supported by a steering shaft (4) so as to be rotatable relative to each other in the axial direction (X). 12) and is provided on the inner periphery (11a) of the outer jacket and pressed against the outer periphery (12a) of the inner jacket. The shock absorbing projections (22, 23) are interposed between the inner circumference of the outer jacket and the outer circumference of the inner jacket, and are held by the first holding portion (25) on the inner circumference of the outer jacket. An annular first seal member (24) sealing between the inner periphery of the outer jacket and the outer periphery of the inner jacket, and the inner jacket An annular second seal that is inserted into the outer jacket during the contraction of the steering column and seals between the inner circumference of the outer jacket and the outer circumference of the inner jacket. A sealed space (S) formed between the first seal member and the second seal member inserted into the outer jacket when the steering column is contracted. Provided is an impact-absorbing steering device (1; 1P) configured to be contracted as the steering column contracts.

According to a second aspect of the present invention, the second seal member includes an elastic member, and an outer diameter (D1; D11) of the second seal member before being inserted into the outer jacket is an inner diameter of the outer jacket. It may be made larger than (D2).
Further, as in claim 3, the outer jacket is provided on the inner periphery of the end (11U) on the sliding direction (X1) side, and the diameter is increased toward the sliding direction. Part (111) may be included.

According to a fourth aspect of the present invention, the second seal member is provided on the outer periphery of the end portion (261) on the insertion direction (X2) side into the outer jacket, and the diameter thereof is reduced toward the insertion direction. The diameter-reduced portion (263) may be included.
Further, as in claim 5, at least one of the shock absorbing projections (22) may have an end (22a) on the sliding direction (X1) side close to the first seal member. .

  According to a sixth aspect of the present invention, the outer periphery of the inner jacket has an enlarged diameter portion (120) close to the end portion (11U) on the sliding direction (X1) side of the outer jacket at the end of the shock absorbing stroke. And the second seal member (260) is disposed on the opposite side of the first end portion and the first end portion (261) as the end portion on the insertion direction (X2) side to the outer jacket. A second end portion (262) proximate to the enlarged diameter portion of the inner jacket.

  According to the first aspect of the present invention, shock absorption energy is obtained by frictional sliding between the shock absorbing protrusion and the inner jacket in the entire region of the shock absorbing stroke. Further, when the second seal member is inserted into the outer jacket and seals between the jackets during the contraction of the steering column when absorbing the shock, the gap between the first and second seal members is between the jackets. A sealed space is formed. The sealed space is contracted with the contraction of the steering column, the internal pressure (air pressure) of the sealed space is increased, and a reaction force against the contraction of the steering column is generated. Thereby, since the shock absorption energy due to the increase in internal pressure is added to the shock absorption energy due to frictional sliding, a sufficient amount of shock absorption energy as a whole can be obtained. In addition, as the end of the shock absorbing stroke is approached, the internal pressure can be increased and the shock absorbing energy can be progressively increased, so that the bottom load can be suppressed and the peak load can be suppressed.

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
According to the invention of claim 2, since the second seal member inserted into the outer jacket slides relative to the inner jacket in a state of being elastically compressed in the radial direction, It can contribute to improvement.

According to the invention of claim 3, when the steering column is contracted, the second seal member is guided by the enlarged diameter portion of the end portion of the outer jacket, and the second seal member is smoothly inserted into the outer jacket. Can do.
According to the invention of claim 4, when the steering column is contracted, the second seal member is smoothly inserted into the outer jacket from the reduced diameter side.

According to the invention of claim 5, when the steering column is contracted, it is possible to suppress the detachment of the first seal member from the first holding portion of the outer jacket. Thereby, the internal pressure rise of sealed space can be achieved reliably.
According to the invention of claim 6, since the second seal member continues to increase the amount of insertion into the outer jacket until just before the end of the shock absorbing stroke, the shock absorbing energy can be improved.

It is a mimetic diagram showing a schematic structure of an impact absorption steering device of one embodiment of the present invention. It is a schematic sectional drawing of the principal part of the shock absorption steering apparatus at the normal time. It is sectional drawing of the principal part of the initial shock absorption steering apparatus at the time of a secondary collision. It is sectional drawing of the principal part of an impact-absorbing steering device in a state where the outer jacket has reached the end position of the impact-absorbing stroke. It is sectional drawing of the principal part of the impact-absorbing steering apparatus of another embodiment of this invention, and has shown the normal time. FIG. 6 is a cross-sectional view of the shock absorbing steering device of FIG. 5, showing a state just before the end of the shock absorbing stroke. FIG. 6 is a cross-sectional view of the shock absorbing steering device of FIG. 5 and shows a state at the end of the shock absorbing stroke.

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an impact absorbing steering apparatus 1 according to an embodiment of the present invention. Referring to FIG. 1, an impact absorbing steering device 1 includes a steering member 2 such as a steering wheel, and a steering mechanism 3 that steers steered wheels (not shown) in conjunction with the steering of the steering member 2. Yes. As the steering mechanism 3, for example, a rack and pinion mechanism is used.

  The steering member 2 and the steering mechanism 3 are mechanically connected via a steering shaft 4, an intermediate shaft 5, and the like. The rotation of the steering member 2 is transmitted to the steering mechanism 3 via the steering shaft 4 and the intermediate shaft 5. Further, the rotation transmitted to the steering mechanism 3 is converted into an axial movement of a rack shaft (not shown). Thereby, a steered wheel is steered.

  The steering shaft 4 includes a cylindrical upper shaft 6 and a lower shaft 7 which are fitted so as to be relatively slidable by, for example, spline fitting or serration fitting, and can be expanded and contracted in the axial direction X. The steering member 2 is connected to the upper end portion of the upper shaft 6 in the axial direction. The steering shaft 4 is inserted through a cylindrical steering column 8 and is rotatably supported by the steering column 8 via a plurality of bearings 9 and 10.

The steering column 8 includes an outer jacket 11 as a cylindrical upper jacket and an inner jacket 12 as a lower jacket that are fitted so as to be slidable relative to each other in the axial direction X. The steering column 8 can be expanded and contracted in the axial direction X.
The outer jacket 11 supports the upper shaft 6 via a bearing 9 so as to be rotatable. The outer jacket 11 is connected to the upper shaft 6 via a bearing 9 so as to be able to move in the axial direction X of the steering shaft 4.

  Further, on the outer periphery of the inner jacket 12, a lower-side column bracket 16 that is rotatably supported via a tilt support shaft 15 is fixed to a lower-side fixing bracket 14 that is fixed to the vehicle body-side member 13A. ing. The steering column 8 and the steering shaft 4 are rotatable about a tilting support shaft 15 as a fulcrum. The height of the steering member 2 can be adjusted (so-called tilt adjustment) by rotating the steering shaft 4 and the steering column 8 with the tilting support shaft 15 as a fulcrum.

  The inner jacket 12 forms an enlarged diameter portion 120 in a region from a position spaced a predetermined distance from the lower end 11U as an end in the axial direction X of the outer jacket 11 to a lower end 12U as one end in the axial direction X. With respect to the axial direction X, the end 121 of the enlarged diameter portion 120 facing the lower end 11U of the outer jacket 11 in the axial direction X is formed in a tapered shape, for example.

  An upper side column bracket 17 is fixed to the outer jacket 11, and the column bracket 17 and an upper side fixed bracket 18 fixed to the vehicle body side member 13B are connected by a lock mechanism 19, whereby a steering column. The position of 8 is fixed to the vehicle body side member 13B, and the position of the steering member 2 is fixed. The lock mechanism 19 includes a lock shaft 21 that passes through the column bracket 17 and the fixed bracket 18 and tightens them together with the rotation operation of the operation lever 20.

  Referring to FIG. 1 and FIG. 2 which is an enlarged cross-sectional view, a plurality of first shock absorbing projections 22 and a plurality of second impacts are pressed on the inner periphery 11 a of the outer jacket 11 and are pressed against the outer periphery 12 a of the inner jacket 12. Absorption protrusions 23 are provided. Specifically, each of the shock absorbing protrusions 22 and 23 is formed in a bulge on the inner periphery 11 a of the outer jacket 11 by forming a recess on the outer periphery of the outer jacket 11, and is caulked on the outer periphery 12 a of the inner jacket 12. It is a caulking projection that is attached. When the steering column 8 contracts during a secondary collision, as shown in FIG. 3 (starting state of shock absorbing stroke) and FIG. 4 (ending state of shock absorbing stroke), the shock absorbing protrusions 22 and 23 are Friction sliding on the outer periphery 12a of the jacket 12 generates shock absorbing energy.

  Although not shown, each of the first shock absorbing projections 22 and the second shock absorbing projections 23 is arranged at regular intervals in the circumferential direction of the inner periphery 11 a of the outer jacket 11. The first shock absorbing protrusions 22 and the second shock absorbing protrusions 23 are spaced apart in the axial direction X. The first shock absorbing protrusion 22 is disposed closer to the steering member 2 than the second shock absorbing protrusion 23.

  Between the inner periphery 11a of the outer jacket 11 and the outer periphery 12a of the inner jacket 12, an annular made of an elastic member such as rubber that seals between the inner periphery 11a of the outer jacket 11 and the outer periphery 12a of the inner jacket 12 is used. The first seal member 24 is interposed. Although not shown, the first seal member 24 may have an annular seal lip that fits to the outer periphery 12 a of the inner jacket 12. The first seal member 24 is disposed in the vicinity of the end 22a on the sliding direction side (first direction X1 side) of the first shock absorbing projection 22.

  A part of the first seal member 24 is accommodated and held in a first holding portion 25 formed of a circumferential groove provided on the inner circumference 11 a of the outer jacket 11. Therefore, when the steering column 8 contracts during the secondary collision, and the outer jacket 11 moves in the first direction X1 which is the contraction side in the axial direction X and is the sliding direction with respect to the inner jackt 12, the first The seal member 24 moves along with the outer jacket 11.

  An annular second seal member 26 made of an O-ring made of an elastic member such as rubber is held on the outer periphery 12a of the inner jacket 12 at a position closer to the first direction X1 than the lower end 11U of the outer jacket 11. . A part of the second seal member 26 is housed and held in a second holding portion 27 formed of a circumferential groove provided on the outer periphery 12 a of the inner jacket 12. The outer diameter D1 of the second seal member 26 is larger than the inner diameter D2 of the outer jacket 11 (D1> D2).

  At the time of the secondary collision, the second seal member 26 is inserted into the outer jacket 11 in the middle of contraction of the steering column 8, and the second seal member 26 after insertion is inserted between the inner circumference 11 a of the outer jacket 11 and the inner jacket 12. The space between the outer periphery 12a is sealed. Thereby, a sealed space S is formed between the jackets 11 and 12 by the first seal member 24 and the second seal member 26, and the sealed space S is contracted as the steering column 8 contracts.

  According to the present embodiment, the impact due to the frictional sliding between the shock absorbing projections 22 and 23 and the inner jacket 12 in the entire region of the shock absorbing stroke ST (the region from the state of FIG. 2 to the state of FIG. 4). Obtain absorbed energy. Further, when the second seal member 26 is inserted into the outer jacket 11 and seals between the jackets 11 and 12 during the contraction of the steering column 8 during shock absorption (see FIG. 3), both the jackets 11 and 12 are sealed. A sealed space S is formed between the first seal member 24 and the second seal member 26.

  As shown in FIGS. 3 and 4, the sealed space S is contracted with the contraction of the steering column 8, and the internal pressure (air pressure) of the sealed space S increases, and the reaction force R resists the contraction of the steering column 8. Is generated. Thereby, since the shock absorption energy due to the increase in internal pressure is added to the shock absorption energy due to frictional sliding, a sufficient amount of shock absorption energy as a whole can be obtained. In addition, as the end of the shock absorbing stroke ST is approached, the internal pressure can be increased and the shock absorbing energy can be progressively increased, so that the occurrence of bottoming can be suppressed and the peak load can be suppressed.

As shown in FIG. 2, the outer diameter D1 of the second seal member 26 before insertion is made larger than the inner diameter D2 of the outer jacket 11. Therefore, the second seal member 26 inserted into the outer jacket 11 slides relative to the inner jacket 12 in a state of being elastically compressed in the radial direction, which contributes to an improvement in impact absorption energy. it can.
Further, since the first shock absorbing projection 22 has its end 22a on the sliding direction side close to the first seal member 24, the steering column 8 is contracted (see FIGS. 3 and 4). The detachment of the first seal member 24 from the first holding portion 25 of the outer jacket 11 can be suppressed. Thereby, the internal pressure rise of sealed space S can be achieved reliably.

  Further, as shown in FIG. 2, the second seal member 26 is made of, for example, an O-ring, and the end of the second seal member 26 on the insertion direction side (first direction X1 side) into the outer jacket 11. The outer periphery of each comprises a reduced diameter portion 26a that is reduced in diameter in the insertion direction (first direction X1). Therefore, when the steering column 8 is contracted, the second seal member 26 is smoothly inserted into the outer jacket 11 from the reduced diameter portion 26a side.

Although not shown, the outer jacket 11 is provided on the inner circumference of the end (lower end 11U) on the sliding direction (first direction X1) side, and the diameter is increased toward the sliding direction. An enlarged diameter part may be included. Also in this case, the second seal member 26 can be smoothly inserted into the outer jacket 11.
Next, FIG. 5 shows an enlarged cross-sectional view of a main part of an impact absorbing steering apparatus 1P according to another embodiment of the present invention. This embodiment is mainly different from the embodiment of FIG. That is, in the present embodiment, the second seal member 260 has a cylindrical shape and extends in the axial direction X. The second seal member 260 is accommodated and held in a second holding portion 270 formed of a circumferential groove provided on the outer periphery 12 a of the inner jacket 12. The outer diameter D11 of the second seal member 260 is larger than the inner diameter D2 of the outer jacket 11 (D11> D2).

The second seal member 260 is disposed in the vicinity of the lower end 11U in the axial direction X of the outer jacket 11, and has a first end 261 as an end on the insertion direction (second direction X2) side to the outer jacket 11; And a second end portion 262 which is disposed on the opposite side of the first end portion 261 and is close to the enlarged diameter portion 120 (the end portion 121 thereof) of the inner jacket 12.
On the outer periphery of the first end 261 that is the end of the second seal member 260 on the insertion direction (second direction X2) side, a taper-shaped contraction that is reduced in diameter toward the insertion direction (second direction X2). A diameter portion 263 is provided.

  The outer jacket 11 is provided on the inner periphery 11a of the end (lower end 11U) on the sliding direction (first direction X1) side, and the diameter is increased toward the sliding direction (first direction X1). The taper-shaped enlarged diameter portion 111 is included. In the constituent elements of this embodiment, the same constituent elements as those of the embodiment of FIG. 2 are denoted by the same reference numerals as those of the embodiment of FIG.

  According to the present embodiment, as in the embodiment of FIG. 2, a sufficient amount of shock absorption energy can be obtained, and the peak load can be suppressed. Further, when the steering column 8 is contracted, the second seal member 260 is guided by the enlarged diameter portion 111 at the lower end 11 in the axial direction X of the outer jacket 11, and the second seal member 260 is smoothly inserted into the outer jacket 11. be able to.

In addition, since the second seal member 260 has the reduced diameter portion 263, the second seal member 260 is smoothly inserted into the outer jacket 11 from the reduced diameter portion 263 side when the steering column 8 is contracted.
Further, since the second end portion 262 of the second seal member 260 is close to the enlarged-diameter portion 120 (the end portion 121) of the inner jacket 12, it is just before the end of the shock absorbing stroke shown in FIG. Until the state (see FIG. 6), a new portion of the second seal member 260 is inserted into the outer jacket 11, and the amount of insertion of the second seal member 260 into the outer jacket 11 continues to increase. Therefore, impact absorption energy can be improved.

  As shown in FIG. 5, the outer diameter D11 of the second seal member 260 before insertion is made larger than the inner diameter D2 of the outer jacket 11. Therefore, since the second seal member 260 inserted into the outer jacket 11 slides relative to the inner jacket 12 in a state of being elastically compressed in the radial direction, it contributes to an improvement in impact absorption energy. it can.

In the present embodiment, the second seal member 260 may eliminate either the reduced diameter portion 263 or the increased diameter portion 111 of the outer jacket 11.
The present invention is not limited to the above embodiment, and the outer jacket 11 may be a lower jacket and the inner jacket 12 may be an upper jacket. Further, an O-ring may be used as the first seal member 24. In addition, various modifications can be made within the scope of the claims of the present invention.

  DESCRIPTION OF SYMBOLS 1; 1P ... Shock absorption steering device, 2 ... Steering member, 3 ... Steering mechanism, 4 ... Steering shaft, 6 ... Upper shaft, 7 ... Lower shaft, 8 ... Steering column, 11 ... Outer jacket, 11a ... Inner circumference, 11U ... lower end in the axial direction (end on the insertion direction side), 12 ... inner jacket, 12a ... outer periphery, 22 ... first shock absorbing projection, 22a ... sliding side end, 23 ... second shock absorbing projection 24 ... 1st seal member, 25 ... 1st holding part, 26 ... 2nd seal member, 26a ... Diameter reduction part, 27 ... 2nd holding part, 111 ... Diameter expansion part, 120 ... Diameter expansion part, 121 ... End 260, second seal member, 261, first end (end on the insertion direction side), 262, second end, 263, reduced diameter portion, D1, outer diameter (of the second seal member), D2 ... (Inner diameter of outer jacket , S ... closed space, ST ... shock absorbing stroke, X ... axial direction, X1 ... first direction (sliding direction of the outer jacket), X2 ... second direction (insertion direction of the second seal member)

Claims (6)

A steering column that includes an outer jacket and an inner jacket that are rotatably supported and rotatably supported by a steering shaft, and that contracts with a predetermined shock absorption stroke at the time of a secondary collision;
A shock-absorbing protrusion provided on the inner periphery of the outer jacket and pressed against the outer periphery of the inner jacket;
It is interposed between the inner circumference of the outer jacket and the outer circumference of the inner jacket, and is held by the first holding portion on the inner circumference of the outer jacket so that it is between the inner circumference of the outer jacket and the outer circumference of the inner jacket. A sealed annular first seal member;
An annular shape that is held by a second holding portion on the outer periphery of the inner jacket and is inserted into the outer jacket during the contraction of the steering column and seals between the inner periphery of the outer jacket and the outer periphery of the inner jacket. A second seal member,
A sealed space formed between the first seal member and the second seal member inserted into the outer jacket when the steering column is contracted is contracted as the steering column contracts. Shock absorbing steering device. In Claim 1, the 2nd seal member contains an elastic member,
A steering column device, wherein an outer diameter of the second seal member before being inserted into the outer jacket is larger than an inner diameter of the outer jacket.   3. The shock absorbing steering apparatus according to claim 2, wherein the outer jacket is provided on an inner periphery of an end portion on a sliding direction side thereof and includes a diameter-expanded portion that is enlarged in diameter toward the sliding direction.   4. The shock absorbing structure according to claim 2, wherein the second seal member is provided on an outer periphery of an end portion on an insertion direction side into the outer jacket and includes a reduced diameter portion that is reduced in diameter toward the insertion direction. Steering device.   5. The shock absorbing steering device according to claim 1, wherein at least one of the shock absorbing protrusions has an end portion on a sliding direction side in proximity to the first seal member. 6. In any one of Claims 1-5, the outer periphery of the said inner jacket contains the diameter expansion part which adjoins the edge part of the sliding direction side of the said outer jacket at the terminal of an impact absorption stroke,
The second seal member is disposed on the opposite side of the first end portion as an end portion on the insertion direction side of the outer jacket, and is close to the enlarged diameter portion of the inner jacket. And a second end portion.

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