JP3395429B2 - Shock absorbing steering device - Google Patents

Abstract

PURPOSE: To surely protect a driver and to stabilize the attitude of a steering wheel by simultaneously and surely contracting a steering column and a steering shaft in the case of collision accident. CONSTITUTION: The front end of a steering shaft 2 is detachably supported on the second bearing 4 in the front end part of a steering column 1. A holding tube 17 to hold the second bearing 4 is firmly supportingly fixed to the front end of the steering column 1. A retaining ring 18 supported on the steering shaft 2 and the holding tube 17 are mutually butted, and the steering shaft 2 is also contracted in the case of the contraction of the steering column 1.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock-absorbing steering device which is incorporated in a steering device of an automobile to transmit the movement of a steering wheel to a steering gear. Further, in the event of a collision, it functions to reduce the overall length while absorbing the impact energy generated at the time of the collision, thereby preventing the steering wheel from applying a large impact to the driver's body. 2. Description of the Related Art In a vehicle steering system, it is necessary to transmit the movement of a steering wheel operated by a driver to a steering gear. Also, in the event of a collision, a so-called secondary collision occurs in which the driver's body collides with the steering wheel, following a so-called primary collision in which the vehicle collides with another vehicle or the like. During a primary collision, the front of the collapsed vehicle pushes the steering components backwards. For this reason, if no countermeasures are taken, the steering wheel may protrude backward toward the driver, possibly causing serious harm to the driver's body. Also, at the time of the secondary collision, the driver's body vigorously hits the steering wheel. For this reason, in order to reduce the impact applied to the driver's body at the time of the secondary collision, it is necessary to gradually displace the steering wheel forward. For such a purpose, a shock absorbing steering apparatus having a structure as shown in FIGS. 5A and 6 has been widely used. This shock absorbing type steering apparatus has a cylindrical steering column 1, which is inserted into the inside of the steering column 1, and whose front and rear ends (left and right ends in FIG. 5) are axially moved from an end opening of the steering column 1. (A left-right direction in FIG. 5). A portion near the rear end (right end in FIG. 5) of the steering shaft 2 is provided on the inner peripheral surface of the rear end (right end in FIG. 5) of the steering column 1 as a first bearing 3 which is a deep groove ball bearing. With this, only the rotation is supported freely. A second bearing, which is a needle bearing, is provided with a portion near the front end (left end in FIGS. 5 and 6) of the steering shaft 2 on the inner peripheral surface of the front end (left end in FIGS. 5 and 6) of the steering column 1. 4 supports the shaft so as to be freely rotated and displaced in the axial direction. A sleeve 6 made of an elastic material such as hard rubber or synthetic resin is provided around a metal cylindrical race 5 constituting the second bearing 4, and this sleeve 6 is attached to the front end of the steering column 1. Pressed into the part. Press-fit strength is, for example, 100kg
f is regulated. Further, a positive radial gap is provided in the second bearing 4 so that the rotation and the axial displacement can be smoothly performed. The sleeve 6
Has also a function as a race for preventing foreign matter from entering the second bearing 4. Further, the steering column 1 and the steering shaft 2 each have an impact absorbing structure for shortening the entire length thereof under a strong compressive load. First, the steering column 1 is formed by combining a cylindrical outer column 7 and an inner column 8 each made of metal in a telescopic manner. The inner peripheral surface of the front end of the outer column 7 and the outer peripheral surface of the rear end of the inner column 8 are fitted with sufficiently large strength. Therefore, the steering column 1 has a sufficiently large bending strength, but when a strong compressive load (impact load) is applied in the axial direction, the fitting portion slides to shorten the overall length. [0005] The steering shaft 2 has a front end inner peripheral surface of a tubular outer shaft 9 and a rear end outer peripheral surface of a cylindrical inner shaft 10 which are each formed in an oval section having two parallel planes. The entire length is made flexible by being formed into a shape and fitted together. Through holes 11 and 11 formed in the front end of the outer shaft 9 and the recess 1 formed in the outer peripheral surface of the rear end of the inner shaft 10
2 and 12 are filled with synthetic resins 13 and 13, respectively. Therefore, the entire length of the steering shaft 2 is not inadvertently reduced, and the joint between the two shafts 9, 10 does not rattle. When a strong compressive load (impact load) is applied in the axial direction, the synthetic resin 13, 13 is torn at the boundary between the through holes 11, 11 and the recesses 12, 12, and the steering shaft 2 Allow the overall length of the to shrink. A shock absorbing type steering device including the above-described steering column 1 and the above-described steering shaft 2 supports an intermediate portion of the outer column 7 on a vehicle body under a dashboard or the like. Then, the front end of the inner column 8 is supported on the vehicle body at a more front side portion. For this purpose, a rear support bracket 14 is fixed to the middle portion of the outer column 7 by welding or the like, and a front support bracket 15 is fixed to the front end of the inner column 8 by welding or the like. The front support bracket 15 is fixed to the vehicle body with a bolt or the like (not shown). On the other hand, the rear support bracket 14 also supports the vehicle body with bolts (not shown). However, when a strong forward (leftward in FIG. 5) force is applied, the rear support bracket 14 loses the support force on the vehicle body and moves forward. It is displaced. The shock absorbing steering apparatus constructed as described above reduces the overall length of the steering column 1 and the steering shaft 2 in the event of a collision, thereby reducing the impact applied to the driver's body. First, when the front portion of the vehicle body is crushed by the primary collision and a strong rearward force acts on the front ends of the steering column 1 and the steering shaft 2, the entire length of the steering column 1 and the steering shaft 2 absorbs the energy of the collision. This prevents the steering wheel fixed to the rear end of the steering shaft 2 from protruding toward the driver's body. Further, when the driver's body collides with the steering wheel due to inertia (secondary collision occurs), the total length of the steering column 1 and the steering shaft 2 also shortens the total length while absorbing the energy of the collision. Then, the steering wheel is displaced forward to reduce the impact applied to the driver's body. [0008] In the case of the shock absorbing type steering apparatus constructed and operated as described above, it is desired to improve the following points. That is, there is no particular problem if it is a collision accident that occurs normally.However, such as an accident in which a passenger car collided with a large vehicle such as a truck, only the front upper part of the vehicle body is collapsed in the primary collision, and the front lower part is not collapsed In certain special accidents, the protection of the driver may be uncertain. For this reason, FIG. 5 (A) and FIG.
This will be described with reference to FIG. In the case of a special accident as described above, only the inner column 8 is pushed rearward via the front support bracket 15 without the front end of the steering shaft 2 being pushed backward. As a result, as shown in FIGS. 5B and 7, only the entire length of the steering column 1 is reduced without reducing the entire length of the steering shaft 2, and the front end of the steering shaft 2 protrudes greatly forward of the steering column 1. . In a subsequent secondary collision, the rear support bracket 1
4 is disengaged from the vehicle body, and further displaces the steering wheel supported and fixed to the rear end of the steering shaft 2 forward while reducing the overall length of the steering column 1 and the overall length of the steering shaft 2. Although the impact energy of a collision accident is absorbed in this way, in the case of the above-described special accident, the total length of the steering shaft 2 is not reduced and only the entire length of the steering column 1 is reduced in the case of a primary collision. Therefore, the entire length of the steering column 1 is reduced by a relatively light compressive load,
The impact energy of the primary collision is insufficiently absorbed, and the overall length of the steering column 1 is excessively reduced. Then, the contraction amount L to be secured for absorbing the shock at the time of the subsequent secondary collision
(FIG. 5B) may be insufficient. [0011] Furthermore, if a secondary collision occurs in a special different form of accident in which the front portion of the vehicle is not much collapsed at the time of the primary collision and the position of the front support bracket 15 is not moved, FIG. As shown in FIG. 8C and FIG. 8, there is a possibility that the front end of the steering shaft 2 protrudes greatly from the front end opening of the steering column 1 forward. That is, even in this case, if there is a large resistance to the front end of the steering shaft 2 being displaced forward, the overall length of the steering shaft 2 is reduced, and the front end of the steering shaft 2 is opened at the front end opening of the steering column 1. Does not protrude significantly from However, due to a special accident such as falling rock or hitting a curbstone, in the event of a primary collision, the universal joint and intermediate shaft provided between the steering shaft 2 and the steering gear are damaged, and the upper part is damaged. If not, the steering shaft 2 is displaced forward without reducing the overall length, and the front end of the steering shaft 2 is connected to the steering column 1 as described above.
May protrude greatly from the front end opening. In this state, the front end of the steering shaft 2 receives a load in the radial direction or swings due to the front end of the steering shaft 2 interfering with some member, and is provided at the rear end of the steering shaft 2. The direction of the steering wheel may change. Although the direction change of the steering wheel is slight, it is not preferable because the direction of the airbag or the like is deviated from the normal direction. As a method for addressing the above-mentioned problem,
As the second bearing, one that prevents displacement in the axial direction, such as a deep groove ball bearing, or a stopper that abuts with the second bearing 4 may be provided at the front end of the inner shaft 10. Can be considered. However, if a second bearing that prevents displacement in the axial direction is used, not only is the assembly of the constituent members troublesome, but also dimensional errors and assembly errors, and furthermore, the steering column 1 and the steering column due to temperature changes. Since the dimensional change with the shaft 2 cannot be absorbed, it cannot be actually used. Further, even if a stopper is provided at the front end of the inner shaft 10 for abutment with the second bearing 4, the second bearing 4 may come off from the front end of the steering column 1. No effect. That is, as described above, the fitting strength of the second bearing 4 to the steering column 1 is about 100 kgf, but the compression load applied to the steering shaft 2 due to the secondary collision is often larger than this, and The load required to reduce the overall length of the shaft 2 is often 100 kgf or more. For this reason, the second bearing 4 is simply attached to the front end of the inner shaft 10.
Even if a stopper is provided to collide with the steering shaft, the overall length of the steering shaft 2 cannot be reliably reduced in the event of a collision.
The shock absorbing steering device of the present invention has been invented in view of such circumstances. [0014] The shock absorbing steering device of the present invention, like the aforementioned conventional shock absorbing steering device, is inserted into a cylindrical steering column and inside the steering column. A steering shaft having both front and rear ends projecting in the axial direction from an end opening of the steering column, and a portion of the steering shaft near the rear end on the inner peripheral surface of the rear end of the steering column, which can rotate only freely. A first bearing for supporting the steering shaft; and a second bearing for supporting a portion of the steering shaft near the front end on the inner peripheral surface of the front end of the steering column so as to be rotatable and axially displaceable.
The steering column and the steering shaft each have an impact absorbing structure for shortening the entire length based on a strong compressive load. [0015] In particular, in the shock absorbing steering device of the present invention, the second bearing is a sleeve made of an elastic material.
Of the steering shaft and the middle of the steering shaft
It is a needle bearing provided between the outer peripheral surface of the portion.
The sleeve is made of a metal plate having an L-shaped cross section.
It is held inside a cylindrical holding cylinder. or,
The inner diameter of the ring formed at the axial end of the holding cylinder is
The circumscribed circles of the needles that compose the needle bearing
Smaller than the diameter. Further, the holding cylinder is firmly held inside the front end of the steering column. In the middle portion of the steering shaft, which is slightly intermediate from the second bearing, the sleeve
A stopper surface is provided which is free to abut against the end face of the holding cylinder or the annular portion of the holding cylinder . According to the shock absorbing steering apparatus of the present invention constructed as described above, not only the entire length of the steering column but also the entire length of the steering shaft can be reliably reduced in the event of a collision. That is, even if only the entire length of the steering column starts to shrink, the stopper surface provided on the steering shaft and the end surface of the sleeve or the circle of the holding cylinder may be used.
The compression load applied to the steering column is also transmitted to the steering shaft based on the collision with the limb. S
Since the holding cylinder holding the second bearing via the leave is held firmly to the steering column, the transmission of the compressive load from the steering column to the steering shaft is reliably performed. Therefore, in any of the primary collision and the secondary collision, the energy associated with the collision is efficiently absorbed, and the driver facing the steering wheel can be sufficiently protected. 1 and 2 show a first embodiment of the present invention. The feature of the present invention lies in a structure for preventing the appearance of a state in which only the steering column 1 shrinks and the steering shaft 2 does not shrink in a collision accident. Since the configuration and operation of the other parts are the same as those of the conventional structure described above, the illustration and description of the equivalent parts will be omitted or simplified, and the following description will focus on the characteristic parts of the present invention. At the front end (left end in FIGS. 1 and 2) of the inner column 8 constituting the steering column 1, a thin portion 16 having an inner diameter larger than other portions is formed. The sleeve 6 for holding the second bearing 4 is fitted via a holding cylinder 17 which is also a member for holding the second bearing 4. The holding cylinder 17 is formed by forming a metal plate into a cylindrical shape with an L-shaped cross section, and has a length slightly smaller than the entire length of the thin portion 16. Therefore, in a state where the holding cylinder 17 is pushed to the inside of the thin portion 16, the edge portion of the thin portion 16 (FIGS.
The left edge protrudes from the edge of the holding cylinder 17 (the left edge in FIGS. 1 and 2). Thus, the protruding edge portion is bent all the way or partially inward in the diametrical direction to suppress the edge of the holding cylinder 17. As a result, the holding cylinder 17
The second bearing 4 held inside the holding cylinder 17 via the sleeve 6 is firmly held inside the front end of the inner column 8. In the middle part of the inner shaft 10 constituting the steering shaft 2, a part slightly closer to the middle than the second bearing 4 (toward the right in FIGS. 1 and 2) has a ring shape. The retaining ring 18 is locked, and one side surface (the left side surface in FIGS. 1 and 2) of the retaining ring 18 is provided on the holding cylinder 17.
The stopper surface is configured to be able to abut against the circular ring portion 19 . This circle
The inner diameter R ₁₉ of the loop 19 constitutes the needle bearing 4.
It is smaller than the diameter D ₄ of the circumscribed circle of the plurality of needles (R ₁₉
<D ₄ ). According to the shock absorbing steering apparatus of the present invention configured as described above, not only the entire length of the steering column 1 but also the entire length of the steering shaft 2 can be reliably reduced in the event of a collision. That is, even if only the entire length of the steering column 1 starts to contract due to the special collision accident as described above, the abutment between the one side surface of the retaining ring 18 locked at the intermediate portion of the steering shaft 2 and the circular ring portion 19 is performed. , The compressive load applied to the steering column 1 is also transmitted to the steering shaft 2. That is,
Normally, as shown in FIG.
Are slightly separated from each other. In such a normal state, the gap 20 between the retaining ring 18 and the circular ring portion 19 exists in order to compensate for dimensional errors and assembly errors of the constituent members. When a collision accident occurs and the total length of the steering column 1 is reduced by the dimension δ of the gap 20,
As shown in FIG. 2, one side surface of the retaining ring 18 and the above-mentioned annular portion 19 abut against each other, and the compressive load applied to the steering column 1 is also transmitted to the steering shaft 2. As described above, since the holding cylinder 17 including the annular portion 19 is firmly held at the front end of the steering column 1, the transmission of the compressive load from the steering column 1 to the steering shaft 2 is reliably performed. . Therefore, in any of the primary collision and the secondary collision, the energy associated with the collision is efficiently absorbed, and the driver facing the steering wheel can be sufficiently protected. Further, since the front end of the steering shaft 2 does not greatly protrude from the front end opening of the steering column 1, the steering shaft 2 is not displaced in the swing direction inside the steering column 1. Therefore, the attitude of the steering wheel supported and fixed to the rear end of the steering shaft 1 does not change. FIG. 3 shows a second embodiment of the present invention. In the case of the present embodiment, the step portion 21 is provided at a middle portion of the inner shaft 10 constituting the steering shaft 2, which is slightly closer to the middle than the second bearing 4 (toward the right in FIG. 3). The stepped portion 21 is formed as a stopper surface which can abut against the ring portion 19 . Other configurations and operations are the same as those of the above-described first embodiment. FIG. 4 shows a third embodiment of the present invention. In the case of the present embodiment, the ring portion 19 of the holding cylinder 17 is provided on the front side (left side in FIG. 4). When the retaining ring 18 abuts on the sleeve 6 in the event of a collision, the annular portion 19 receives a load via the second bearing 4. In this embodiment, the reason why the length of the holding cylinder 17 is smaller than the length of the sleeve 6 is to make it easier to insert the race 5 into the sleeve 6 during the assembling operation. The shock absorbing steering apparatus of the present invention is constructed and operates as described above, so that the steering column and the steering shaft can be contracted almost simultaneously and reliably in the event of a collision. it can. For this reason, it is possible to reliably protect the driver in the event of a collision, including a special accident. In addition, since a change in the attitude of the steering wheel can be prevented, the effect of the airbag device can be reliably obtained, and the protection of the driver in the event of a collision can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a first embodiment of the invention in a normal state, FIG.
The figure corresponding to the left end part of (A). FIG. 2 is a view similar to FIG. 1, showing a state after the collision. FIG. 3 is a view similar to FIG. 1, showing a second embodiment of the present invention. FIG. 4 is a view showing the third embodiment and corresponding to the left part of FIG. 1; FIG. 5 is a longitudinal sectional side view showing a conventional structure in a normal state and in a state of each of primary and secondary collisions. FIG. 6 is a diagram corresponding to the left end of FIG. FIG. 7 is a view corresponding to the left end of FIG. 5 (B). FIG. 8 is a view corresponding to the left end of FIG. [Description of Signs] 1 Steering column 2 Steering shaft 3 First bearing 4 Second bearing 5 Race 6 Sleeve 7 Outer column 8 Inner column 9 Outer shaft 10 Inner shaft 11 Through hole 12 Depression 13 Synthetic resin 14 Rear support bracket 15 Front support bracket 16 Thin section 17 Holding cylinder 18 Retaining ring 19 Ring section 20 Gap 21 Step

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 1/19

Claims (1)

(57) [Claim 1] A cylindrical steering column, and a steering wheel which is inserted inside the steering column and whose front and rear ends project axially from an end opening of the steering column. A first bearing for rotatably supporting a portion of the steering shaft near the rear end on the inner peripheral surface of the rear end of the steering column;
A second bearing for supporting a portion of the steering shaft near the middle front end on the inner peripheral surface of the front end of the steering column so as to be freely rotatable and displaceable in the axial direction. The steering column and the steering shaft are each strongly compressed. In the shock-absorbing steering device having a shock-absorbing structure that shortens the entire length based on a load, the second bearing includes an inner peripheral surface of an elastic sleeve.
Outer periphery of the middle part of the steering shaft near the front end
Needle bearing provided between the three
The metal plate is a metal plate with an L-shaped cross section and a cylindrical shape.
It is held inside the holding cylinder, and the axial end of the holding cylinder
The inner diameter of the ring formed in the above constitutes the needle bearing
Smaller than the circumscribed circle diameter of multiple needles, holding above
Cylinder is firmly held to the front end portion inner side of the steering column, above the second portion closer to the middle slightly than the bearing at the intermediate portion of the steering shaft, the
A shock-absorbing steering device, wherein a stopper surface is provided which is capable of abutting against an end surface of a sleeve or a circular portion of the holding cylinder .