JPH0995245A - Impact absorption type steering column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently and appropriately absorb the impact energy at the time of collision of a vehicle, and to securely prevent the apply of an excessive load to a driver by using a spacer made of the synthetic resin in an impact absorption type steering column. SOLUTION: A cylindrical second column 2b is pressed into a cylindrical first column 2a through a spacer 3. As a material of the spacer 3, the ultrahigh molecular weight polyethylene at 500,000-6,000,000, desirably at 3,000,000-4,500,000 of molecular weight is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing steering column used for absorbing a shock applied to a driver in a vehicle collision.

[0002]

2. Description of the Related Art An impact absorption type steering column in which a tubular second column is press-fitted into a tubular first column via a tubular spacer so as to absorb impact energy by the relative movement of both columns in the axial direction. Proposed (Actual Kaihei 1-
172965). The spacer prevents both columns from twisting each other, and smoothly moves both columns in the axial direction.

[0003]

It has been proposed to use a synthetic resin as a material for the spacer. However, a synthetic resin material having a normal molecular weight is easily softened at a high temperature and has a low strength such as tensile strength and a low hardness. , When it is press-fitted into the first column via the spacer of the second column, it is easily plastically deformed, and the shrinkage becomes large at low temperature. Therefore, the press-fitting load becomes too small, and the impact energy cannot be sufficiently absorbed. On the other hand, if the toughness of the synthetic resin material used as the material of the spacer is low, it tends to be broken during impact action and impairs the impact absorbing function. Further, if the synthetic resin material has a large friction coefficient, the spacer impedes the relative movement of the first column and the second column in the axial direction at the time of impact, and an excessive load acts on the driver at the time of absorbing the impact. Therefore, a spacer made of synthetic resin cannot be put to practical use as a spacer in the shock absorbing steering column.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shock absorbing type steering column which can solve the above-mentioned problems of the prior art.

[0005]

According to the present invention, in a shock absorbing steering column in which a tubular second column is press-fitted into a tubular first column via a tubular spacer, the material of the spacer is molecular weight. Is more than 500000 and 60000
It is characterized in that it is an ultra high molecular weight polyethylene of 00 or less. It is preferable that the molecular weight of the ultra high molecular weight polyethylene used as the material of the spacer is 3,000,000 or more and 45,000,000 or less.

When the spacer is made of ultra-high molecular weight polyethylene having a molecular weight of 500,000 or more, it is less likely to be softened at high temperatures and has a higher tensile strength than that made of a normal thermoplastic synthetic resin having a molecular weight of about 100,000. And the like, the second column is press-fitted into the first column via a spacer, and is not easily plastically deformed. Further, the second column is less likely to shrink at low temperatures. As a result, the press-fitting load can be prevented from becoming too small, and the impact energy can be sufficiently absorbed. The ultra high molecular weight polyethylene has toughness and an appropriate hardness (Shore hardness D67-7).
Since it has 0), it is hard to crack when an impact is applied, and
When the second column is press-fitted into the column via the spacer, it is not easily plastically deformed, so that impact energy can be sufficiently absorbed. Further, since the ultra high molecular weight polyethylene has a small coefficient of friction, it does not hinder the relative movement of the first column and the second column in the axial direction during impact,
It is possible to prevent an excessive load from acting on the driver during shock absorption. The molecular weight of the ultra high molecular weight polyethylene is 60
When it is 00000 or less, the moldability in molding the spacer can be improved, so that the dimensional accuracy can be improved, the press-fitting load can be accurately managed, and the impact energy can be appropriately absorbed. The effect at the time of impact absorption by increasing the molecular weight of the ultra high molecular weight polyethylene is improved as the molecular weight increases up to 3,000,000, and the effect at the time of impact absorption is reduced even when the molecular weight exceeds 3,000,000. There is no such thing. Therefore, its molecular weight is preferably 3,000,000 or more. Also,
By setting the molecular weight to 45,000,000 or less, the moldability in molding the spacer can be further improved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The shock absorbing steering column 1 shown in FIG. 1 comprises a cylindrical first metallic column 2a and a second metallic column 2b press-fitted into the first column 2a via a cylindrical spacer 3. Prepare

The first column 2a supports a cylindrical first handle shaft 5 via a bearing 4. The first
A steering wheel (not shown) is connected to one end of the handle shaft 5, one end of the second handle shaft 7 is inserted into the other end, and the second handle shaft 7 is supported by the second column 2b via a bearing 6. The bearing 4 that supports the first handle shaft 5 is
Due to the step formed on the inner circumference of the column 2a and the retaining ring 12 mounted on the outer circumference of the first handle shaft 5, relative movement in the axial direction with respect to the first column 2a and the first handle shaft 5 is restricted.

An upper bracket 11 is welded to the first column 2a, and the first column 2a is supported by the vehicle body via the upper bracket 11 and a shock absorbing mechanism described later.

A lower bracket 10 is attached to the second column 2b.
Are welded, and the second column 2b is supported by the vehicle body via the lower bracket 10.

As shown in FIG. 2, a pair of peripheral grooves 8 are formed on the outer periphery of the second handle shaft 7, and a through hole 9 communicating with the peripheral groove 8 is formed in the first handle shaft 5, and the through hole is formed. 9 and the circumferential groove 8 are filled with the resin 60. When an impact is applied, the resin 60 is broken, and the first handle shaft 5 and the second handle shaft 7 move relatively in the axial direction. The inner peripheral shape of the first handle shaft 5 and the outer peripheral shape of the second handle shaft 7 are non-circular, so that the first
The handle shaft 5 and the second handle shaft 7 are connected so that rotation can be transmitted.

As shown in FIG. 3, FIG. 4 and FIG. 5 (1), the upper bracket 11 has a pair of support portions 11a extending outward in the radial direction of the first column 2a and the support portions 11a. A side wall portion 11d extending from one end in a direction perpendicular to the axial direction of the first column 2a, and a protrusion 1 extending from one end of each side wall portion 11d in parallel to the axial direction of the first column 2a.
1e and a ring 11h integrated with each protrusion 11e. A notch 11b that opens on the steering wheel side is formed in each support portion 11a, and each notch 11b is formed.
The connecting member 20 is inserted in the.

As shown in FIG. 5B, each connecting member 2
0 has an upper part 20a which enters the inner surface of each notch 11b, and a lower part 20b along the lower surface around each notch 11b.
A plurality of through-holes 11g are formed in portions of each support portion 11a along the periphery of the notch 11b. A through hole 20c communicating with each through hole 11g is formed in a lower portion 20b of each connecting member 20.
A synthetic resin pin 61 is inserted into the through holes 11g and 20c. Each pin 61 is integrated with a holding member 61 'along the upper surface around each notch 11b. Each connecting member 20
And a shock absorbing member 6 made of sheet metal on the upper surface of each holding member 61 '.
3 is moved along. Bolt through holes 63 ′, 20 ′ formed in one end of each shock absorbing member 63 and each connecting member 20.
Then, the screw shaft 40 implanted in the vehicle body side member 45 is inserted. The nut 41 screwed to the screw shaft 40 and the vehicle body side member 45 form the shock absorbing member 63 and the holding member 6.
1 ', the support portion 11a and the connecting member 20 are sandwiched.
Thereby, one end side of the shock absorbing member 63 is connected so as to move with the vehicle body. In addition, each bolt through hole 63 ',
Reference numeral 20 'designates a long hole in the column axis direction in the longitudinal direction, which can cope with positional deviation between members due to manufacturing errors. When an impact is applied, the pins 61 are sheared, the upper bracket 11 thereof accompanies the first column 2a, and the vehicle body and the second column 2b are axially aligned with the first column 2a.
The shock absorbing member 63, the holding member 61 ′, and the connecting member 20 move relative to each other.

As shown in FIG. 6, each shock absorbing member 63
Is a first portion 63a extending in the axial direction of the first column 2a from one end to the other end, and the first portion 63a.
a second portion 63b extending from a along a direction perpendicular to the axial direction of the first column 2a, and a second portion 63b thereof.
Has a third portion 63c extending in the axial direction of the first column 2a from the other end to the other end, and the other end is a free end. The first portion 63a of each shock absorbing member 63 is sandwiched between the holding member 61 'and the vehicle body-side member 45 and connected to the vehicle body as described above. The second portion 63b of each shock absorbing member 63 corresponds to each supporting portion 11a of the upper bracket 11.
It is inserted into the opening 11f formed in. The third portion 63c of each shock absorbing member 63 is inserted into a ring 11h integrated with each protrusion 11e of the upper bracket 11.

As shown in FIG. 7A, the opening 11
One side of the peripheral edge portion of f is a first pressing portion 11j, which faces the second portion 63b on one end side of the shock absorbing member 63 with a space δ. The first pressing portion 11j has a convex curved surface. At a position away from the first pressing portion 11j in a direction perpendicular to the axial direction of the first column 2a, the boundary portion between the side wall portion 11d of the upper bracket 11 and the protruding portion 11e constitutes the second pressing portion 11k. . The second pressing portion 11k has the second portion 63
It faces b on the other end side of the shock absorbing member 63. The second pressing portion 11k has a convex curved surface. The inner surface of the ring 11h is a guide portion 11h 'capable of restricting relative movement of the third portion 63c in a direction intersecting the axial direction of the first column 2a.

As shown in (1) and (2) of FIG. 8 and FIG. 9, the spacer 3 has a cylindrical shape, and has a split groove 3a along the axial direction so that it can be elastically deformed in the radial direction. ing. The spacer 3 is molded from an ultrahigh molecular weight polyethylene material by injection molding or the like, and the molecular weight of the ultrahigh molecular weight polyethylene is 5,000,000 or more and 6,000,000.
It is set as follows, preferably 3,000,000 or more and 45,000
00 or less.

An inwardly projecting flange 3b is formed at one end of the spacer 3, and the flange 3b contacts the end surface of the second column 2b. The spacer 3 has a plurality of ridges 3d formed along the axial direction in a plurality of regions on the outer circumference thereof which are spaced in the circumferential direction. The outer peripheral region 3e where the protrusion 3d is not formed is a flat cylindrical surface. As a result, the inner peripheral surface of the first column 2a is provided with the protrusions 3d.
To contact the spacer 3 through. As shown in (3) of FIG. 9, the height dimension h of the protrusion 3d of the spacer 3 in the state of being press-fitted between the columns 2a and 2b is the thickness dimension of the portion 3f where the protrusion 3d is not formed. It is smaller than D3.

As shown in FIG. 10, the total thickness dimension D2 of the spacer 3 before press-fitting is larger than the gap dimension D1 between both columns 2a and 2b, and the spacer 3 projects from the total thickness dimension 2 of the spacer 3 before press-fitting. The dimension D3 obtained by subtracting the height H of the strip is made smaller than the gap dimension D1 between the columns 2a and 2b. The spacer 3 before press-fitting is fitted to the outer periphery of the second column 2b, and the flange 3b at one end thereof is the second column 2b.
Abut on the end face of The first column 2a is press-fitted into the outer periphery of the spacer 3, and the protrusions 3d are compressed and deformed during the press-fitting. The total thickness dimension D2 of the spacer 3 before press fitting
, D2>D1> D
3 is established, the total thickness dimension D2 of the spacer 3 before press-fitting and the height dimension H of the protrusion 3d are set.

In the above structure, when a shock is applied by the collision of the vehicle, the shock is first absorbed by shearing the resin 60 and the pin 61.

Next, the first column 2a moves relative to the vehicle body and the second column 2b, so that both columns 2a, 2b are moved.
The shock is absorbed according to the press-fitting load of the spacer 3 press-fitted in between. The total thickness dimension D2 of the spacer 3 before press fitting is larger than the gap dimension D1 between the columns 2a and 2b,
From the total thickness dimension D2 of the spacer 3 before press-fitting to the protrusion 3d
The dimension D3 less the height dimension H of the two columns 2a, 2
Since it is smaller than the gap dimension D1 between b, the amount of compressive deformation when the spacer 3 is press-fitted is smaller than that when the inner and outer peripheries of the spacer are flat cylindrical surfaces. As a result, even if the gap dimension D1 between the columns 2a and 2b and the total thickness dimension D2 of the spacer 3 before press-fitting vary depending on the working tolerance, the variation of the compression deformation amount at the press-fitting of the spacer 3 due to the variation. The load can be reduced, and the variation in the load required for the axial relative movement of both columns 2a, 2b corresponding to the press-fit load can be reduced. A two-dot chain line in FIG. 11 indicates a gap dimension D between the columns 2a and 2b when the total thickness dimension D2 of the spacer 3 before press fitting is constant.
The relation between the variation from the set value of 1 and the load required for the relative movement in the axial direction is shown. It can be confirmed that it is smaller than the variation. Thereby, the load required for the axial relative movement of both columns 2a, 2b can be set within an appropriate range, and the impact energy can be properly absorbed. Also, both columns 2a, 2
By making the height dimension h of the protrusion 3d of the spacer 3 in the state of being press-fitted between b smaller than the thickness dimension D3 of the portion 3f where the protrusion 3d is not formed, the spacer 3
Is made of ultra-high molecular weight polyethylene and is more easily deformed than metal or the like, the relative inclination of both columns 2a, 2b due to the deformation of the protrusion 3d at the time of impact is reduced, and the protrusion 3d is also reduced. Part 3 that is not formed and is difficult to deform
Since both columns 2a and 2b can be guided by f to be relatively moved in the axial direction, both columns 2a and 2b can be smoothly moved in the axial direction to appropriately absorb the impact energy.

After the first column 2a moves relative to the vehicle body by the distance δ between the second portion 63b of the shock absorbing member 63 and the first pressing portion 11j of the upper bracket 11, the shock absorbing member 63 is moved. The plastic deformation causes the shock to be absorbed. That is, as shown in (2) of FIG. 7, when the first column 2a moves relative to the vehicle body by the distance δ, the second portion 63b thereof is pressed against the first pressing portion 11j. Further, when the first column 2a moves relative to the vehicle body, the boundary portion between the first portion 63a and the second portion 63b of the shock absorbing member 63 is plastically deformed. Due to the plastic deformation, the second portion 63b is pressed against the second pressing portion 11k as shown in (3) of FIG. When the first column 2a further moves relative to the vehicle body, as shown in FIG. 12, the first pressing portion 11j and the second pressing portion 11k plastically deform the shock absorbing member 63 with the relative movement.

As a result, as shown in FIG. 13, the relationship between the relative movement stroke of the first column 2a with respect to the vehicle body and the load acting on the driver can be made small in the initial stage of shock absorption, and the large load on the driver can be obtained. The shock can be effectively absorbed without acting on.

According to the above construction, the spacer 3 is made of ultra-high molecular weight polyethylene having a molecular weight of 500,000 or more, so that it is softened at a high temperature as compared with a usual thermoplastic synthetic resin having a molecular weight of about 100,000. It becomes difficult, the strength such as tensile strength is improved, and when the second column 2b is press-fitted into the first column 2a via the spacer 3, it is not easily plastically deformed, and it is difficult to shrink at low temperature.
As a result, the press-fitting load can be prevented from becoming too small, and the impact energy can be sufficiently absorbed. Further, since the ultra-high molecular weight polyethylene has toughness and an appropriate hardness (Shore hardness D67 to 70), it is hard to be cracked at the time of impact action, and the second column 2b is press-fitted into the first column 2a through the spacer 3. Since it does not easily plastically deform when it is subjected to impact, it can absorb impact energy sufficiently. Further, since the ultra high molecular weight polyethylene has a small friction coefficient, it does not hinder the relative movement of the first column 2a and the second column 2b in the axial direction at the time of impact action, and an excessive load acts on the driver at the time of impact absorption. Can be prevented. By setting the molecular weight of the ultra high molecular weight polyethylene to 6,000,000 or less, the moldability of the spacer 3 can be improved, so that the dimensional accuracy can be improved, the press-fitting load can be accurately controlled, and the impact energy can be properly absorbed. it can. When the molecular weight of the ultra high molecular weight polyethylene is 3,000,000 or more, the effect at the time of impact absorption is further improved,
Moldability can be improved more by setting it as 0000 or less.

The present invention is not limited to the above embodiment. For example, the shape of the spacer is not particularly limited as long as it is cylindrical, and the protruding shape as described above is not essential. Further, the structure of the shock absorbing mechanism is not particularly limited.

[0026]

According to the impact absorption type steering column of the present invention, the impact energy is sufficiently and properly absorbed at the time of the collision of the vehicle by using the spacer made of the synthetic resin, and the excessive load acts on the driver. It can be surely prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view of a steering column according to an embodiment of the present invention.

FIG. 2 is a partial side sectional view of a steering column according to an embodiment of the present invention.

FIG. 3 is a partial side view of the steering column according to the embodiment of the present invention.

FIG. 4 is a partial plan view of the steering column according to the embodiment of the present invention.

5 is a sectional view of the steering column of the embodiment of the present invention taken along the line VV in FIG. 3, and (2) is a perspective view of a holding member and a connecting member.

FIG. 6 is a perspective view of an upper bracket and a shock absorbing member of the steering column according to the embodiment of the present invention.

FIG. 7 is a sectional view of an upper bracket and an impact absorbing member of a steering column according to an embodiment of the present invention before impact, (2) is a sectional view after relative movement of δ after impact, and (3) ) Is a cross-sectional view during shock absorption

FIG. 8 is a perspective view of a spacer of the steering column according to the embodiment of the present invention.

FIG. 9 is a vertical sectional view of the spacer according to the embodiment of the present invention, (2) is a horizontal sectional view, and (3) is a partial sectional view in a press-fitted state between both columns.

FIG. 10 is an explanatory diagram of a dimensional relationship of spacers according to the embodiment of the present invention.

FIG. 11 is a diagram showing the relationship between the variation in the gap between both columns and the load required to relatively move both columns in the axial direction.

FIG. 12 is a partial side view of the steering column after an impact action.

FIG. 13 is a diagram showing the relationship between the relative movement stroke of the first column of the steering column and the vehicle body and the load acting on the driver.

[Explanation of symbols]

 1 Steering column 2a 1st column 2b 2nd column 3 Spacer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuzo Hirukushi 3-5-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka Koyo Seiko Co., Ltd. (72) Hiromi Isogawa 3-5, Minamisenba, Chuo-ku, Osaka-shi, Osaka No. 8 Within Koyo Seiko Co., Ltd. (72) Inventor Susumu Imagaki 3-5-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka Within Koyo Seiko Co., Ltd. (72) Inventor Akio Matsuda 1-5 Tosabori, Nishi-ku, Osaka-shi, Osaka 11 Tosabori IN Building 8F Sumitomo Electric Hybrid Stock Company In-house (72) Inventor Yoshihisa Amano 7-22-8 Fukushima, Fukushima-ku, Osaka City, Osaka Prefecture Sumitomo Corporation

Claims (2)

[Claims] 1. In an impact absorption type steering column in which a tubular second column is press-fitted into a tubular first column through a tubular spacer, the spacer material is made of ultrahigh molecular weight of 500,000 to 6,000,000. A shock absorption type steering column characterized by being made of molecular weight polyethylene. 2. The ultrahigh molecular weight polyethylene used as the material for the spacer has a molecular weight of 3,000,000 or more and 450,000.
The shock absorbing steering column according to claim 1, wherein the steering column is 0 or less.