JP2013199169A - Energy absorption steering column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy absorption steering column capable of easily and surely imparting frictional load to absorb energy applied to a steering shaft.SOLUTION: A first cylindrical member (upper tube 10) has an outside diameter step part 11 in a position at a predetermined distance away from a vehicle rear opening end and a second cylindrical member (lower tube 20) has an inside diameter step part 21 of an inner circumferential surface smaller than the outside diameter of a large diameter part 13 of the first cylindrical member in the vehicle rear opening end part, and into that, the first cylindrical member is press-fitted. A friction member 30 is wound around the small diameter part 12 of the first cylindrical member to have an outside diameter smaller than the large diameter part and after the large diameter part of the first cylindrical member is removed from the inside diameter step part of the second cylindrical member, the outer circumferential surface of the friction member is arranged to be abutted to the inner circumferential surface of the inside diameter step part of the second cylindrical member.

Description

  The present invention relates to an energy absorbing steering column, and more particularly to an energy absorbing steering column that absorbs energy applied to a steering shaft of a vehicle.

  Energy absorption steering columns mounted on vehicles are widely known as a means to alleviate the impact on the steering wheel by giving the steering column the characteristic of absorbing energy, and various structures are adopted. Yes. For example, in Patent Document 1 below, “a cylindrical metal first column and a cylindrical metal second column that is press-fitted into the first column, and when the steering wheel collides with the driver, In the shock absorption type steering device in which the first column and the second column are moved relative to each other in the axial direction based on the shock of the shock, the shock is absorbed. At least one of the inner periphery of the first column and the outer periphery of the second column In addition, a friction reducing material is applied in a thin film, and the friction coefficient between the friction reducing material and each column is smaller under the same measurement conditions than the friction coefficient between both columns. A second column is press-fitted through the first column ”, an impact absorbing steering device is disclosed.

  Further, in Patent Document 2 below, an annular groove is formed on either one of the inner peripheral surface of the inner diameter step portion of the second cylindrical member and the outer peripheral surface of the small diameter portion of the first cylindrical member, An annular protrusion is formed on either the outer peripheral surface or the inner peripheral surface of the collar member. When the annular protrusion engages with the annular groove, the collar member is locked to one of the second cylindrical member and the first cylindrical member. When the relative movement of the first cylindrical member relative to the second cylindrical member is performed, the outer peripheral surface of at least the outer diameter step portion of the first cylindrical member and the inner peripheral surface of the collar member are frictionally engaged. An "energy absorbing" steering column has been proposed.

JP 2002-302048 A JP 2010-221925 A

  According to the shock absorbing steering device described in Patent Document 1, “the friction coefficient between the friction reducing material and each column is smaller than the friction coefficient between both columns under the same measurement conditions. Further, only the inner diameter of the first column, the outer diameter of the second column, and the coating thickness of the friction reducing material affect the magnitude of the friction force, that is, the friction reducing material is disposed between both columns. In the configuration, the types of dimensions that affect the magnitude of the frictional force are reduced as much as possible, so that the inner diameter dimension of the first column, the outer diameter dimension of the second column, and the coating thickness dimension of the friction reducing material can be reduced. Without the management with such high accuracy, the accumulated error of the dimension can be reduced and the magnitude of the frictional force can be set within an appropriate fixed range, so that the variation in the load acting on the driver at the time of collision is reduced. " Yes. However, the cost of managing the coating thickness dimension of the friction reducing material is large, and there is a concern that the friction reducing material may be peeled off due to a high load during impact. In addition, since the load at the time of impact is not limited to the axial direction but is applied from a plurality of directions, there is a concern that a desired impact absorbing effect cannot be obtained only by the applied friction reducing material.

  On the other hand, according to the steering column described in Patent Literature 2, “the frictional force can be easily adjusted by the collar member, and a stable frictional load can be appropriately applied as the moving load. In particular, since the collar member is formed in a C shape with a synthetic resin, it can be easily assembled and can easily follow when sliding against a mounting object having a different diameter cross section. Therefore, desired energy absorption characteristics can be ensured. However, in order to absorb the energy applied to the steering shaft, a collar member having a predetermined shape and a cylindrical member having a predetermined shape related thereto are required. Basically, the first cylindrical member and the second cylinder are required. Since it is necessary to form both ends of the shaped member into a predetermined shape, a steering column that can apply a friction load more easily with a simpler configuration is desired.

  Therefore, an object of the present invention is to provide an energy absorbing steering column capable of easily and reliably applying a friction load for absorbing energy applied to a steering shaft of a vehicle.

  In order to achieve the above object, the present invention is arranged on the vehicle front side with respect to the first tubular member, which accommodates a steering shaft of the vehicle and supports the steering shaft rotatably about the shaft. A second cylindrical member that houses the first cylindrical member and normally holds the first cylindrical member in a predetermined position, and the second cylinder when a load greater than a predetermined value is applied to the steering shaft. In the energy absorption steering column configured to allow the axial movement of the first cylindrical member relative to the cylindrical member, the first cylindrical member has an outer diameter at a position spaced a predetermined distance from the opening end at the rear of the vehicle. A small-diameter portion that has a step portion and is formed with a relatively small diameter from the outer-diameter step portion toward the rear of the vehicle; adjacent to the small-diameter portion via the outer-diameter step portion; Has a large-diameter part formed to a large diameter In addition, the second cylindrical member has an inner diameter step portion of an inner peripheral surface smaller than the outer diameter of the large diameter portion of the first cylindrical member at an opening end portion at the rear of the vehicle, and the inner diameter step portion A large diameter portion of the first tubular member is press-fitted, and is wound around the small diameter portion of the first tubular member so as to have an outer diameter smaller than the large diameter portion of the first tubular member. A friction member that is locked to a small-diameter portion of one cylindrical member, and when the first cylindrical member is moved relative to the second cylindrical member, the large-diameter portion of the first cylindrical member is After detaching from the inner diameter step portion of the two cylindrical members, the outer peripheral surface of the friction member is arranged so as to contact the inner peripheral surface of the inner diameter step portion of the second cylindrical member.

  In the energy absorbing steering column, the outer peripheral surface of the vehicle front side end portion of the friction member may be formed in a tapered shape having a minimum diameter on the outer diameter step portion side of the first cylindrical member. Furthermore, it is good also as forming the inner peripheral surface of the vehicle rear side edge part in the internal diameter step part of the said 2nd cylindrical member in the taper shape which makes the end surface of the side contact | abutted to the said friction member the maximum diameter.

  In the energy absorbing steering column, the first cylindrical member includes a reduced diameter portion including the outer diameter step portion and extending in the axial direction, and the friction member is a small diameter of the first cylindrical member. It is good to provide the locking tool which locks the said friction member to the said reduced diameter part after being wound by the part. In addition, there exist a rivet and a pin as a locking tool, and it is good also as welding a friction member to a reduced diameter part.

  Furthermore, in the above energy absorbing steering column, the first cylindrical member has a reduced diameter portion including the outer diameter step portion and extending in the axial direction, and through a hole formed in the reduced diameter portion. A resin material may be injected and the friction member may be outsert-molded. In this case, a plurality of holes may be formed in the reduced diameter portion as a pin gate, or a long hole may be formed in the reduced diameter portion, and outsert molding may be performed using this as a gate.

  Since this invention is comprised as mentioned above, there exist the following effects. That is, in the energy absorbing steering column of the present invention, the first tubular member has an outer diameter step portion at a position spaced a predetermined distance from the opening end at the rear of the vehicle, and from the outer diameter step portion toward the rear of the vehicle. The second cylinder has a relatively small diameter portion, a large diameter portion that is adjacent to the small diameter portion via the outer diameter step portion, and has a relatively large diameter toward the front of the vehicle. The inner member has an inner diameter step portion on the inner peripheral surface that is smaller than the outer diameter of the larger diameter portion of the first cylindrical member at the opening end of the rear side of the vehicle, and the inner diameter step portion has a larger diameter of the first cylindrical member. The portion is press-fitted, wound around the small diameter portion of the first cylindrical member so as to have an outer diameter smaller than the large diameter portion of the first cylindrical member, and is locked to the small diameter portion of the first cylindrical member. And a large diameter portion of the first cylindrical member is located within the second cylindrical member when the first cylindrical member is moved relative to the second cylindrical member. Since the outer peripheral surface of the friction member is arranged so as to abut on the inner peripheral surface of the inner diameter step portion of the second cylindrical member after being detached from the step portion, it is wound around the first cylindrical member. A friction load can be easily and reliably applied by the friction member. In particular, the second tubular member can be manufactured easily and easily because the second tubular member can be configured to wind the friction member around the first tubular member while maintaining the conventional shape. Moreover, when the first cylindrical member is assembled to the second cylindrical member, conversely, when the second cylindrical member is assembled to the first cylindrical member, the friction member is attached even after both are assembled. It can be easily attached to the first tubular member. Alternatively, even after the first cylindrical member and the second cylindrical member are assembled to the column housing, the friction member can be mounted on the first cylindrical member, so that the degree of freedom of the assembly line is increased and the assembling property is increased. Will improve.

  For example, the outer peripheral surface of the vehicle front side end portion of the friction member is formed in a tapered shape having a minimum diameter on the outer diameter step portion side of the first cylindrical member, and further, the vehicle in the inner diameter step portion of the second cylindrical member. If the inner peripheral surface of the rear side end portion is formed in a taper shape with the end surface on the side in contact with the friction member having the maximum diameter, the first cylindrical member will be the first cylindrical member without causing so-called galling or galling. The two cylindrical members can be smoothly slid to ensure stable energy absorption characteristics.

  Further, the first cylindrical member has a reduced diameter portion including the outer diameter step portion and extending in the axial direction, and after the friction member is wound around the small diameter portion of the first cylindrical member, the friction member is If it is assumed that a locking tool for locking to the reduced diameter portion is provided, the friction member can be easily attached to the first tubular member by the locking tool. Moreover, even after the first cylindrical member and the second cylindrical member are assembled to the column housing, the friction member can be easily attached to the first cylindrical member by the locking tool.

  Alternatively, if the resin material is injected through the hole formed in the reduced diameter portion of the first cylindrical member and the friction member is outsert molded, the resin friction member can be easily formed into the first cylindrical member. Can be installed.

1 is a cross-sectional view of an energy absorption steering column according to an embodiment of the present invention. It is a longitudinal cross-sectional view which shows the connection part of the upper tube and lower tube in one Embodiment of this invention. It is a sectional side view which shows the connection part of the upper tube and lower tube in one Embodiment of this invention. It is sectional drawing which expands and shows the normal relationship of the upper tube, lower tube, and friction member in one Embodiment of this invention. It is sectional drawing which expands and shows the relationship at the time of the energy absorption operation | movement of the upper tube, lower tube, and friction member in one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the other aspect of the junction part of the lower tube and friction member in one Embodiment of this invention. It is a sectional side view which shows the other aspect of the junction part of the lower tube and friction member in one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the other aspect of the junction part of the lower tube and friction member in one Embodiment of this invention. It is a sectional side view which shows the other aspect of the junction part of the lower tube and friction member in one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the connection part of the upper tube and lower tube in other embodiment of this invention. It is a longitudinal cross-sectional view which shows the connection part of the upper tube and lower tube in other embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of an energy absorbing steering column according to an embodiment of the present invention. A steering shaft 1 includes a cylindrical upper shaft 1a having a steering wheel (not shown) connected to a rear end portion thereof, The lower shaft 1b is spline-coupled to the inner cylindrical surface of the upper shaft 1a. That is, the upper shaft 1a and the lower shaft 1b are connected so as to be relatively movable in the axial direction but not to be relatively rotatable, and the front end portion of the lower shaft 1b is connected to a steering mechanism (not shown). The steering shaft 1 is mounted on a vehicle body (not shown) by a bracket (not shown) via a column housing (also called a main housing or main tube) 2 so as to form a predetermined angle with respect to a vehicle floor (not shown). Support).

  In the column housing 2, a metal upper tube 10 is provided as a first cylindrical member that houses the steering shaft 1 and supports the steering shaft 1 so as to be rotatable about the shaft. That is, the upper shaft 1 a accommodated in the upper tube 10 is rotatably supported by the rear end portion of the upper tube 10 via the bearing 3. However, the relative movement in the axial direction between the upper shaft 1a and the upper tube 10 is restricted, and the upper shaft 1a and the upper tube 10 are configured to be able to move in the axial direction integrally. Further, the second cylindrical member is disposed on the vehicle front side (left side in FIG. 1) with respect to the first cylindrical member, and accommodates the first cylindrical member and normally holds the first cylindrical member in a predetermined position. A metal lower tube 20 is provided, and the lower tube 20 is supported by the column housing 2. And when the load more than predetermined value is applied with respect to the steering shaft 1, it is comprised so that the axial direction relative movement of the upper tube 10 with respect to the lower tube 20 (hence, the axial direction movement of the upper shaft 1a) is permitted, In the present embodiment, the upper tube 10 and the lower tube 20 function as energy absorbing means.

  The upper tube 10 of this embodiment is also called an inner tube, and as shown in FIG. 2, has an outer diameter step portion 11 at a position spaced a predetermined distance from the opening end at the rear of the vehicle. A small-diameter portion 12 formed with a relatively small diameter toward the rear, and a large-diameter portion 13 that is adjacent to the small-diameter portion via an outer-diameter step portion 11 and formed with a relatively large diameter toward the front of the vehicle. Have. The lower tube 20 is also called an outer tube, and has an inner diameter step portion 21 having an inner peripheral surface smaller than the outer diameter of the large diameter portion 13 of the upper tube 10 at an opening end at the rear of the vehicle. 21 is configured such that the large-diameter portion 13 of the upper tube 10 is press-fitted into the upper tube 10, and the upper tube 10 is in a state in which the pressing load of the inner diameter step portion 21 of the lower tube 20 is applied to the large-diameter portion 13. Held in.

  Then, the friction member 30 is wound around the small-diameter portion 12 of the upper tube 10 and is locked to the small-diameter portion 12 so that the outer diameter is smaller than that of the large-diameter portion 13 of the upper tube 10. The friction member 30 of the present embodiment is formed in a band shape with a metal material that can be elastically deformed, and the outer peripheral surface of the front end portion of the vehicle has a tapered shape with the outer diameter step portion 11 side of the upper tube 10 as the minimum diameter. (Indicated by 31 in FIG. 4). Further, the inner diameter step portion 21 of the lower tube 20 is formed such that the inner peripheral surface of the vehicle rear side end portion is tapered so that the end surface on the side in contact with the friction member 30 has the maximum diameter (22 in FIG. 4). ).

  As shown in FIGS. 2 and 3, the upper tube 10 includes a reduced diameter portion 14 including the outer diameter step portion 11 and extending in the axial direction, and the friction member 30 is wound around the small diameter portion 12 of the upper tube 10. After being mounted, it is locked to the reduced diameter portion 14 by a total of four rivets (represented by 41) as locking tools. The outer peripheral surface of the reduced diameter portion 14 is a flat surface as shown in FIGS. 2 and 3, and the upper tube 10 of the portion is formed in a substantially D-shaped cross section. Although protruding into the tube 10, its head is accommodated in the space between the lower tube 20 and the reduced diameter portion 14. In addition, there exists a pin etc. as a latching tool, and it is good also as welding joining, and these are later mentioned with reference to FIG. 6 thru | or FIG.

  As described above, since the friction member 30 is wound around the small diameter portion 12 of the upper tube 10 and is fixed to the reduced diameter portion 14 by the rivet 41, the upper tube 10 is assembled to the lower tube 20. On the other hand, when the lower tube 20 is assembled to the upper tube 10, the friction member 30 can be easily mounted even after both are assembled. Alternatively, even after the upper tube 10 and the lower tube 20 are assembled to the column housing 2, the friction member 30 can be mounted on the small-diameter portion 12 of the upper tube 10, so that the degree of freedom of the assembly line is increased and the assembling property is increased. Will improve.

  Thus, during the relative movement of the upper tube 10 with respect to the lower tube 20, the upper tube 10 moves forward and friction is applied to the large-diameter portion 13 in a state where a pressing load is applied to the inner diameter step portion 21 of the lower tube 20. When a load (press-fit load) is generated, the upper tube 10 is further driven against this friction load, and the large diameter portion 13 of the upper tube 10 is disengaged from the engagement with the inner diameter step portion 21 of the lower tube 20, the lower The inner diameter step portion 21 of the tube 20 is returned in the axial direction and comes into contact with the friction member 30. As a result, the inner peripheral surface of the inner diameter step portion 21 of the lower tube 20 and the outer peripheral surface of the friction member 30 are frictionally engaged, and a friction load is applied as the friction member 30 passes through the inner diameter step portion 21. ing.

  Explaining the operation of the energy absorbing steering column configured as described above, the large diameter portion 13 of the upper tube 10 is normally press-fitted into the inner diameter step portion 21 of the lower tube 20 in the state shown in FIGS. The upper tube 10 is held in a state of being pressed by the lower tube 20, and as shown in an enlarged view in FIG. 4, the upper tube 10 and the lower tube 20 are held in a state in which relative movement in the axial direction is prevented.

  Next, when a load of a predetermined value or more is applied to the steering shaft 1, the steering shaft 1 moves forward together with the upper tube 10, and when the large diameter portion 13 of the upper tube 10 is detached from the inner diameter step portion 21 of the lower tube 20, the upper tube 10 advances in a state where the separation speed is maintained, and the friction member 30 comes into contact with the inner diameter step portion 21 of the lower tube 20 as shown in FIG. Thereafter, the inner peripheral surface of the inner diameter step portion 21 of the lower tube 20 and the outer peripheral surface of the friction member 30 are in a frictional engagement state, whereby a friction load is applied to the upper tube 10 and moves while absorbing energy. To do.

  The friction member 30 of the present embodiment has an outer peripheral surface (31 in FIG. 4) of the vehicle front side end portion formed in a taper shape, and a vehicle rear side end portion of the inner diameter step portion 21 of the lower tube 20. Since the inner peripheral surface (22 in FIG. 4) is also formed in a tapered shape, the upper tube 10 slides smoothly in the lower tube 20 without causing so-called twisting or galling. In addition, since the friction member 30 is used in the elastic deformation region, it is possible to suppress twisting and variation in friction load due to deformation, and to stabilize the energy absorption load with little fluctuation. Thus, a desired energy absorption characteristic can be ensured by the energy absorption steering column configured as described above.

  FIG. 6 and FIG. 7 show a mode in which a total of four pins (represented by 42) are used in place of the rivet 41 as a locking tool, and the tip thereof is located in the upper tube 10. Although protruding, the head is accommodated in the space between the reduced diameter portion 14 of the upper tube 10 and the lower tube 20. 8 and 9 show a mode in which the friction member 30 is welded to the reduced diameter portion 14 of the upper tube 10 and is joined by a total of five welds (represented by 43). Among these, the welding part 43 shown on the upper right and lower sides of FIG. 8 represents the state by which the vehicle rear side edge part of the friction member 30 was weld-joined to the reduced diameter part 14 over the perimeter. In any embodiment, after the belt-shaped friction member 30 is wound around the small-diameter portion 12 of the upper tube 10, both ends thereof are brought into contact with each other with a slight gap, and the pin 42 or welding is performed. It is fixed to the reduced diameter portion 14 by (43). In addition, the other structure in the aspect shown in FIG. 6 thru | or FIG. 9 is the same as that of FIG.

  10 and 11 relate to another embodiment of the present invention, and show the configuration of a friction member 30x formed of a resin material, and the other configuration is the same as that of FIG. In the embodiment shown in FIG. 10, a plurality of holes (typically indicated by 15) are formed as pin gates in the reduced diameter portion 14 of the upper tube 10, and the resin material is injected through these holes 15. Then, the friction member 30x is outsert-molded. In this case, after the friction member 30x is formed, injection molding is performed from the inside of the upper tube 10 through the hole 15 so that a gate mark does not remain on the outer peripheral surface.

  In the embodiment shown in FIG. 11, a long hole 16 is formed in the reduced diameter portion 14 of the upper tube 10, a resin material is injected using this as a gate, and the friction member 30x is outsert molded. Thereby, since it becomes a key-shaped gate, compared with embodiment shown in FIG. 10, a section modulus improves and the shear stress at the time of generating a missing load is strengthened.

1 Steering shaft 1a Upper shaft 1b Lower shaft 10 Upper tube (first tubular member)
20 Lower tube (second cylindrical member)
11 Outer diameter step portion 12 Small diameter portion 13 Large diameter portion 14 Reduced diameter portion 21 Inner diameter step portion 30, 30x Friction member

Claims (5)

  A first cylindrical member that receives a steering shaft of a vehicle and supports the vehicle so as to be rotatable around an axis, and is disposed on the vehicle front side with respect to the first cylindrical member, and stores the first cylindrical member at all times. A second cylindrical member that holds the first cylindrical member in a predetermined position, and an axial direction of the first cylindrical member with respect to the second cylindrical member when a load greater than a predetermined value is applied to the steering shaft. In the energy absorbing steering column configured to allow relative movement, the first tubular member has an outer diameter step portion at a position spaced a predetermined distance from the opening end at the rear of the vehicle, and the outer diameter step portion A small-diameter portion that is relatively small in diameter toward the rear of the vehicle, and a large-diameter portion that is adjacent to the small-diameter portion via the outer diameter step portion and that has a relatively large diameter toward the front of the vehicle. And the second cylindrical member Has an inner diameter step portion having an inner peripheral surface smaller than the outer diameter of the large diameter portion of the first cylindrical member, and the large diameter portion of the first cylindrical member is press-fitted into the inner diameter step portion. And is wound around the small-diameter portion of the first cylindrical member so as to have an outer diameter smaller than the large-diameter portion of the first cylindrical member, and is locked to the small-diameter portion of the first cylindrical member. A friction member, and when the first tubular member is moved relative to the second tubular member, the large-diameter portion of the first tubular member is separated from the inner-diameter step portion of the second tubular member. An energy absorbing steering column, wherein the outer peripheral surface of the friction member is disposed so as to contact the inner peripheral surface of the inner diameter step portion of the second cylindrical member.   2. The energy absorption according to claim 1, wherein an outer peripheral surface of a vehicle front side end portion of the friction member is formed in a taper shape having a minimum diameter on an outer diameter step portion side of the first cylindrical member. Steering column.   The inner peripheral surface of the vehicle rear side end portion of the inner diameter step portion of the second cylindrical member is formed in a taper shape having an end surface on the side in contact with the friction member as a maximum diameter. 2. The energy absorbing steering column according to 2.   The first cylindrical member has a reduced diameter portion including the outer diameter step portion and extending in the axial direction, and the friction member is wound around the small diameter portion of the first cylindrical member, and then the friction The energy absorbing steering column according to any one of claims 1 to 3, further comprising a locking member that locks a member to the reduced diameter portion.   The first cylindrical member includes a reduced diameter portion including the outer diameter step portion and extending in the axial direction, and a resin material is injected through a hole formed in the reduced diameter portion, and the friction member is out. The energy absorbing steering column according to any one of claims 1 to 3, wherein the energy absorbing steering column is formed by sart molding.

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