JP6317248B2 - Electric power steering device - Google Patents

Description

  The present invention relates to an electric power steering apparatus.

  In general, the electric power steering apparatus includes an impact absorption mechanism that performs energy absorption (EA (Energy Absorption)) at the time of the secondary collision in order to protect the driver due to the secondary collision.

  Patent Document 1 discloses a column assist type electric power steering apparatus having an impact absorbing mechanism. This electric power steering apparatus includes a tilt mechanism having a tilt spring that urges the steering column upward, and the upper tube moves relative to (shrinks) the inner tube at the time of a secondary collision, and absorbs shock. It has a mechanism. In addition, the electric power steering apparatus includes a power assist unit that applies assist force to a lower portion of the steering shaft, and a motor, a speed reducer, and a torque sensor that constitute the power assist unit are housed in a housing.

JP2013-1243A

  By the way, in Patent Document 1, when the upper tube moves (contracts) relative to the inner tube at the time of a secondary collision, a housing or the like that houses the power assist unit may interfere with the tilt spring. In this case, a large impact load may occur when the tilt spring and the housing interfere with each other.

  An object of the present invention is to provide an electric power steering apparatus capable of reducing an impact load when an interference object collides with a tilt spring in a secondary collision.

  In order to solve the above-described problems, the present invention provides a tilt mechanism including a tilt spring coupled to a vehicle side bracket and a steering column biased upward by the tilt spring, and an upper tube of the steering column is a lower tube. An impact absorbing mechanism that is fitted so as to be relatively slidable in the axial direction, and that absorbs the impact of the upper tube together with the vehicle side bracket along with the relative movement with respect to the lower tube during a secondary collision; In the electric power steering apparatus provided with a power assist portion provided at a lower portion of the steering column for applying an assist force, the tilt spring has an upper portion coupled to the vehicle side bracket and a lower portion extended forward of the vehicle. It is connected to the upper spring part and the lower part of the upper spring part and is folded back toward the rear of the vehicle. A bent portion, and a lower spring portion disposed from the bent portion to the lower side of the steering column and extending rearward of the vehicle, wherein the bent portion has a taper that extends in a tapered shape toward the front of the vehicle when viewed from above the vehicle. The tapered portion is in initial contact with the power assist portion when the upper tube moves relative to the lower tube.

With this configuration, during the secondary collision, the interference object initially collides with the tilt spring, and the taper portion moves in a direction to avoid the interference, thereby reducing the collision load.
The upper spring portion, the bent portion, and the lower spring portion each include a pair, and each of the pair of portions is disposed symmetrically with respect to the steering column, and the lower spring portion is connected. It is preferable that it is connected via the part.

  With this configuration, during a secondary collision, the interference object initially collides with the tilt spring, and the pair of tapered portions move in a direction to avoid the interference, thereby reducing the collision load.

  According to the present invention, it is possible to reduce the impact load when the interference object collides with the tilt spring in the secondary collision.

The top view which looked at the steering device in one embodiment from the top. Sectional drawing along the axial direction of the steering column of a steering device in one Embodiment. The principal part side view of a steering device. The principal part cross-sectional view of a steering device. The principal part expanded horizontal sectional view of a steering device. The disassembled perspective view of suspension mechanism T1, T2 of a steering device. The perspective view of a tilt spring. The top view of a tilt spring. Explanatory drawing which shows the effect | action of a tilt spring. The characteristic view which shows the relationship between EA stroke at the time of impact absorption, and impact load.

Hereinafter, an embodiment of an electric power steering apparatus 1 (hereinafter referred to as a steering apparatus) embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the steering device 1 includes a steering shaft 3 to which a steering wheel (not shown) is fixed at an end portion on the vehicle rear side (right end portion in FIG. 1). The steering shaft 3 is rotatably supported in the steering column 6 by being supported by a bearing 5. An end portion (left end portion in FIG. 1) on the front side of the vehicle in the steering shaft 3 is coupled to an intermediate shaft (not shown) through a universal joint. Therefore, the rotation and steering torque accompanying the steering operation are transmitted to a steering mechanism that changes the steering angle of a steered wheel (not shown) such as a rack and pinion mechanism. The steering shaft 3 is mounted on the vehicle in an inclined state so that the end portion on the front side of the vehicle is positioned on the lower side in the vertical direction than the end portion on the rear side of the vehicle.

  The steering device 1 also includes a tilt mechanism that enables adjustment of the position of the steering wheel (steering position) in the vertical direction. The steering device 1 also includes a telescopic mechanism that enables adjustment of the steering position in the axial direction of the steering shaft 3.

  As shown in FIG. 2, the steering shaft 3 includes a hollow upper shaft 11 to which a steering wheel (not shown) is fixed, and a lower shaft 12 accommodated in the upper shaft 11. A spline fitting portion 11 a is formed on the inner periphery of the upper shaft 11, and a spline fitting portion 12 a is formed on the outer periphery from the upper portion to the center portion of the lower shaft 12. Further, a lower diameter portion 12b having a diameter larger than that of the upper portion and the intermediate portion is provided at the lower portion of the lower shaft 12. The upper shaft 11 and the lower shaft 12 are configured to be slidable relative to each other in the axial direction when the spline fitting portions 11a and 12a are spline-fitted, and to be integrally rotatable.

  Further, the steering column 6 includes an upper tube 13 (also referred to as an upper jacket) that accommodates and supports the upper shaft 11 via a bearing 5 and a lower tube 14 (also referred to as a lower jacket) that accommodates the lower shaft 12. Yes. The upper tube 13 is fitted to the lower tube 14 so as to be relatively slidable in the axial direction. The relative sliding in the axial direction enables telescopic adjustment described later.

  As shown in FIG. 2, the other end (front end) of the lower tube 14 is disposed around the output shaft 16 and the output shaft 16 of the power assist portion PA that applies assist force for assisting the steering operation to the steering system. A housing 17 is provided in which the torque sensor S is accommodated. As shown in FIG. 2, in the housing 17, the part which accommodates the torque sensor S is formed in a small diameter compared with the part which accommodates the worm wheel 22 mentioned later.

  One end of the output shaft 16 is spline-fitted and connected to the other end of the lower shaft 12, and is supported rotatably with respect to the housing via bearings 19-21. The output shaft 16 constitutes the steering shaft 3 together with the upper shaft 11 and the lower shaft 12.

  A worm wheel 22 accommodated in the housing 17 is fixed to the output shaft 16. Rotation of the motor M supported by the housing 17 is transmitted to the output shaft 16 via a reduction mechanism RG composed of a worm wheel 22 and a worm gear (not shown), thereby applying assist force to the steering system. It is possible. The motor M, the speed reduction mechanism RG, the torque sensor S, and the like constitute a power assist portion PA that applies assist force to the lower portion of the steering column 6.

  As shown in FIG. 2, the steering column 6 (that is, the steering device 1) can tilt around a tilt center axis O provided in the housing 17 with respect to a lower bracket (not shown) provided on a vehicle-side member (not shown). It is supported by.

  By rotating the steering shaft 3 and the steering column 6 around the tilt center axis O, the height position of a steering wheel (not shown) can be adjusted (so-called tilt adjustment). Further, the front-rear direction position of a steering wheel (not shown) can be adjusted (so-called telescopic adjustment) by expanding and contracting the steering shaft 3 and the steering column 6 in the column movement direction X1 (that is, the axial direction).

  As shown in FIGS. 4 and 5, the steering column 6 (that is, the steering device 1) is supported on the vehicle side via an upper bracket 23 on the rear side of the lower bracket (not shown). The upper bracket 23 corresponds to a vehicle side bracket.

  The upper bracket 23 includes a fixed bracket 24 fixed to the vehicle side, a clamp bracket 25 suspended from the fixed bracket 24 via a pair of suspension mechanisms T1 and T2, and a column bracket 26 supported by the clamp bracket 25. Including.

  The fixed bracket 24 and the clamp bracket 25 are made of sheet metal, and are connected and detached, which will be described later, for separating the clamp bracket 25 from a predetermined position (position shown in FIGS. 1 and 3) toward the column moving direction X1 at the time of a secondary collision. A mechanism R is provided.

  The fixing bracket 24 is fixed to a vehicle side member (not shown). The clamp bracket 25 is suspended and supported by the fixed bracket 24 via a suspension bolt 27 as a suspension shaft of the suspension mechanisms T1 and T2. On the other hand, as shown in FIG. 4, a column bracket 26 is fixed to the upper tube 13 (upper jacket) of the steering column 6.

  As shown in FIGS. 4 and 6, the clamp bracket 25 includes a pair of side plates 29 extending downward and a connecting plate 31 that connects the upper ends of the pair of side plates 29, and is substantially in an axial view. It is formed in a U shape. Each side plate 29 has a spring mounting plate 33 formed by being bent in the vehicle width direction. The spring mounting plate 33 has a fixed recess 33a that is recessed downward at the upper end, and a locking groove 33b that is recessed in a lateral L shape at the side end opposite to the side plate 29.

  As shown in FIG. 4, the column bracket 26 includes a pair of side plates 30 respectively facing the pair of side plates 29 of the clamp bracket 25 and a connecting plate 32 that connects the lower ends of the pair of side plates 30. It has a shape.

(Lock mechanism 35)
As shown in FIG. 4, the clamping bracket 25 and the column bracket 26 pass through a fastening shaft 28 made of a bolt. That is, the side plate 30 of the column bracket 26 is formed with a long hole 30a (see FIG. 3) extending in the column moving direction X1 (the direction orthogonal to the paper surface), and the fastening shaft 28 is penetrated. An arc-shaped elongated hole 29a (see FIG. 6) is formed in the side plate 29 of the clamp bracket 25 so as to follow an arc locus centering on the tilt center axis O, and the fastening shaft 28 is penetrated. ing.

  As shown in FIG. 4, a nut 34 is screwed onto the tip of the fastening shaft 28, and a lock mechanism 35 is provided on the head side of the fastening shaft 28. The lock mechanism 35 is composed of a cam mechanism (not shown), for example, and is rotated between the head of the tightening shaft 28 (bolt) and the nut 34 by rotating the cam mechanism by rotating the operation lever 36. 25 is tightened and the column bracket 26 is locked. As a result, the position of a steering wheel (not shown) after tilt adjustment or telescopic adjustment is locked to achieve tilt lock and telescopic lock.

  The lock mechanism 35 has a function of suppressing rattling between the telescopically-locked tubes 13 and 14. Specifically, the lock mechanism 35 includes a cylindrical sleeve 37 that rotates integrally with the tightening shaft 28 as the operation lever 36 rotates, and a cam that is provided on the outer periphery of the sleeve 37 so as to be integrally rotatable. And a pressing portion 38 made of a protrusion. When the sleeve 37 is rotated by the operation of the operation lever 36, the pressing portion 38 pushes up the lower tube 14, and the lower tube 14 is pressed against the upper tube 13 in the radial direction, whereby the lower tube 14 is moved relative to the upper tube 13. Radial backlash is suppressed.

(Tilt spring 40)
As shown in FIGS. 2 and 4, a tilt spring 40, which has end portions hooked on a pair of spring mounting plates 33, is in contact with the lower surface of the sleeve 37 from below, and the biasing force (elasticity) of the tilt spring 40 is retained. The sleeve 37 is biased upward by the force). The tilt spring 40 is a double torsion spring formed from a wire. The front-rear direction of the tilt spring 40 coincides with the front of the vehicle and the rear of the vehicle when mounted on the spring mounting plate 33.

  As shown in FIGS. 7 and 8, the tilt spring 40 includes a connecting portion 42, a pair of pressing action portions 44, a pair of taper portions 46, a pair of torsion portions 48, a pair of extending portions 50, a pair of falling portions 52, and A pair of latching portions 54 are provided.

  The connecting portion 42 extends in the direction Y1 (that is, the vehicle width direction) orthogonal to the column movement direction X1. Further, when assuming a plane that bisects the Y1 direction of the connecting portion 42, in the tilt spring 40, each of the pair of portions is provided to be plane-symmetric with respect to the plane. This can be said to be plane symmetric with respect to the steering column 6 and the steering shaft 3.

  As shown in FIGS. 3 and 4, the tilt spring 40 includes a latching portion 54, a falling portion 52, and an extending portion 50 that are continuously formed from the upper portion, and extends from the latching portion 54 to the extending portion 50. When viewed from the side, it is substantially S-shaped (see FIG. 3). The hook portion 55 that is the tip of the latching portion 54 is positioned on the rear surface side (rear side of the vehicle) of the spring mounting plate 33, and the upper end of the latching portion 54 is engaged with the fixed recess 33a and the lower end is engaged with the locking groove 33b. By being locked, the latching portion 54 is disposed along the front surface of the spring mounting plate 33, and the falling portion 52 is disposed along the rear surface.

  The extending portion 50 connected to the lower end of each falling portion 52 extends forward of the vehicle through the lower side of the spring mounting plate 33 (see FIG. 3), and the torsion portion 48 and the tapered portion 46 are continuously formed. ing. From the extended portion 50 to the tapered portion 46, when viewed from the upper side of the vehicle, the U-shaped portion is folded backward (see FIG. 6).

  The tapered portions 46 connected to the ends of the torsion portions 48 facing each other are arranged so as to be separated from each other toward the front end. In the present embodiment, as shown in FIG. 2, the tapered portion 46 extends obliquely toward the rear upper side as shown in FIG. The torsion part 48 and the taper part 46 correspond to a bent part.

  Further, at the rear end of the taper portion 46, the pressing action portions 44 extend in parallel to each other toward the rear of the vehicle. The rear ends of the pressing portions 44 are integrally connected to each other at the connecting portion 42. The pressing action part 44 corresponds to a lower spring part. Moreover, when it has the connection part 42 like this embodiment, a connection part is also corresponded to a lower spring part.

  Here, the extending part 50, the falling part 52, and the latching part 54 correspond to an upper spring part. The latching portion 54 corresponds to the upper portion of the upper spring portion. The extending part 50 corresponds to the upper part of the upper spring part.

  As shown in FIG. 2, the tilting action of the tilt spring 40 is in contact with the lower surface of the sleeve 37. The tilt spring 40 applies elastic force (biasing force) of the pressing action portion 44, the taper portion 46, the torsion portion 48, the extension portion 50, and the like to the steering column 6 via the sleeve 37.

  As shown in FIG. 2, the tapered portion 46 is disposed so as to face the housing 17. When the steering column 6 contracts during the secondary collision and the tilt spring 40 and the housing 17 collide with each other, both the taper portions 46 expand and absorb the impact.

  In the present embodiment, a tilt mechanism is constituted by the tilt central axis O, the clamp bracket 25 having the long hole 29a, the column bracket 26, the steering column 6, the tilt spring 40, and the like.

(Connecting / disengaging mechanism R)
Next, the connecting / disconnecting mechanism R will be described.
As shown in FIGS. 4 and 5, each suspension mechanism T <b> 1, T <b> 2 includes a suspension bolt 27, a leaf spring 60 made of a disc spring, a nut 62, and the like.

  As shown in FIGS. 4 to 6, the connecting / disconnecting mechanism R includes a resin pin 64 that shears at the time of a secondary collision, and a cylindrical collar 66 that is fitted to a part of the resin pin 64 in the axial direction. Yes. The collar 66 is formed of a material having a higher hardness than the resin forming the resin pin 64 (for example, a metal such as iron or aluminum, a high-hardness resin, ceramic, or the like).

  As shown in FIG. 6, the fixed bracket 24 of the upper bracket 23 includes a pair of side plates 68 extending downward from a pair of side edges of the flat plate portion 67, and an outer side in the vehicle width direction from the pair of side plates 68. And a pair of mounting plates 70 extending to the front. Each mounting plate 70 is provided with an insertion hole 70a (see FIGS. 4 and 6), and is fixed to the vehicle-side member (not shown) by a fixing bolt (not shown) inserted through the insertion hole 70a.

  The flat plate portion 67 of the fixed bracket 24 is provided with a pair of long holes 71. The pair of suspension bolts 27 are inserted through the long holes 71, respectively. The pair of long holes 71 extend in parallel to the column movement direction X1 at the time of the secondary collision, and are separated in a direction Y1 orthogonal to the column movement direction X1.

As shown in FIG. 6, the coupling plate 31 of the clamp bracket 25 is formed with a pair of round holes 72 for the suspension mechanisms T <b> 1 and T <b> 2 that face a part of each long hole 71.
As shown in FIGS. 5 and 6, each suspension bolt 27 includes a leaf spring 60, a corresponding insertion hole 74 of the first interposed plate 73, a corresponding long hole 71 of the flat plate portion 67, and the connecting plate 31. The nuts 62 are fastened with the corresponding round holes 72 sequentially inserted. Thereby, the clamp bracket 25 is supported by being suspended from the fixed bracket 24 via the suspension bolt 27.

  As shown in FIG. 6, the first intervening plate 73 is a long plate extending in the direction Y1 orthogonal to the column moving direction X1, and as shown in FIG. Is intervening. At least the surface on the flat plate portion 67 side of the first interposed plate 73 is made of a low friction material such as a fluororesin. That is, the entire first interposed plate 73 may be made of a low friction material, or the surface of the first interposed plate 73 on the flat plate portion 67 side may be covered with the low friction material.

  Between the flat plate portion 67 and the connecting plate 31, a second interposed plate that functions to reduce sliding resistance when the connecting plate 31 moves in the column moving direction X1 with respect to the flat plate portion 67 at the time of a secondary collision. 75 and a third intervening plate 76 are interposed.

  The second interposed plate 75 constitutes a groove-shaped unit 75U that is locked to the end of the connecting plate 31 on the column moving direction X1 side. As shown in FIG. 6, the unit 75 </ b> U includes a second interposed plate 75 along the upper surface of the connecting plate 31 and the lower surface of the flat plate portion 67, and a counter plate 77 facing the second interposed plate 75 and along the lower surface of the connecting plate 31. And a connecting plate 78 that connects the second interposed plate 75 and the opposing plate 77 and abuts the edge of the connecting plate 31 on the column moving direction X1 side.

  At least the surface on the flat plate portion 67 side of the second interposed plate 75 is made of a low friction material such as a fluororesin. That is, the second interposed plate 75 to unit 75U may be made of a low friction material, or the surface of the second interposed plate 75 on the flat plate portion 67 side may be covered with the low friction material. The third intervening plate 76 constitutes a unit 76U that is locked to the end of the flat plate portion 67 opposite to the column moving direction X1 and the end of the connecting plate 31 opposite to the column moving direction X1. . That is, the unit 76 </ b> U includes a third interposed plate 76 that extends along the upper surface of the connecting plate 31 and the lower surface of the flat plate portion 67, and a counter plate 79 that faces the third interposed plate 76 and extends along the upper surface of the flat plate portion 67. . Further, the unit 76U connects the third interposed plate 76 and the counter plate 79 and contacts the edge of the flat plate portion 67 opposite to the column moving direction X1, and the column moving direction of the connecting plate 31. For example, a hook-shaped hook 81 is hooked and locked to the end opposite to X1. At least the surface of the third interposed plate 76 on the side of the connecting plate 31 is made of a low friction material such as a fluororesin. That is, the third interposed plate 76 to the unit 76U may be made of a low friction material, or the surface of the third interposed plate 76 on the connecting plate 31 side may be covered with the low friction material.

  As shown in FIGS. 4 and 5, each suspension bolt 27 includes a head 82, a large diameter portion 83 that is continuous with the head 82 and has a smaller diameter than the head 82, and a large diameter portion 83 that is continuous with the large diameter portion 83. And a small-diameter screw portion 84. The head portion 82 is provided with a tool engaging portion having a hexagonal hole shape, for example.

  As shown in FIG. 5, the large-diameter portion 83 passes through the annular leaf spring 60, the insertion hole 74 of the first interposed plate 73, and the long hole 71 of the flat plate portion 67. A step portion between the large diameter portion 83 and the screw portion 84 abuts on the upper surface of the connecting plate 31 and is received by the upper surface. The connecting plate 31 is sandwiched between the stepped portion and the nut 62, and the suspension bolt 27 and the connecting plate 31 are fixed.

  The distance between the head portion 82 and the stepped portion (that is, the axial length of the large diameter portion 83) is the thickness of the second interposed plate 75 (or thru | or between the flat plate portion 67 and the connecting plate 31). (Thickness of the third interposed plate 76), the plate thickness of the flat plate portion 67, the plate thickness of the first interposed plate 73 along the upper surface of the flat plate portion 67, and the plate thickness of the leaf spring 60 at the time of maximum compression. Has also been enlarged.

Accordingly, the plate spring 60 elastically biases the flat plate portion 67 toward the connecting plate 31 via the first interposed plate 73.
The resin pin 64 of the connecting / disconnecting mechanism R includes, for example, a head portion 86 having a circular cross section and a shaft portion 87 that is a cylindrical portion having a smaller diameter than the head portion 86.

  The collar 66 is fitted to the outer periphery of the shaft portion 87, and the outer diameter thereof is equal to the outer diameter of the head portion 86 of the resin pin 64. The upper end of the collar 66 in the axial direction is in contact with the head 86 of the resin pin 64, and the lower end of the collar 66 is received by the upper surface of the connecting plate 31. Thereby, the resin pin 64 and the collar 66 are prevented from dropping below the connecting plate 31. Moreover, the 1st interposition board 73 is arrange | positioned so that the upper direction of the head 86 of the resin pin 64 may be covered, and, thereby, the fall of the resin pin 64 upward is prevented.

As shown in FIG. 6, a long hole 88 extending in the direction Y1 perpendicular to the column moving direction X1 is penetrated in a portion closer to the side opposite to the X1 direction in the center between the long holes 71 of the flat plate portion 67.
As shown in FIG. 5, the long hole 88 is for the connecting / disconnecting mechanism R of the flat plate portion 67 of the fixing bracket 24, and the head 86 of the resin pin 64 and most of the collar 66 are the same long hole 88. Is inserted. A part of the collar 66 protrudes from the long hole 88.

  As shown in FIG. 6, the lower portion of the shaft portion 87 of the resin pin 64 that protrudes downward from the collar 66 has a circular cross-section through hole 89 for the connecting / disconnecting mechanism R in the connecting plate 31 of the clamp bracket 25. Thus, it is inserted in the center in the direction Y1 orthogonal to the column moving direction X1. The through hole 89 has an inner diameter that is the same as or slightly larger than the outer diameter of the shaft portion 87.

  At the time of the secondary collision, as the fixed bracket 24 and the clamp bracket 25 move relative to each other, the portion corresponding to the boundary between the collar 66 and the connecting plate 31 can be sheared in the shaft portion 87. The lower part protruding downward from 66 is separated from the remaining part other than the lower part.

  The first absorbing plate 73, the second interposed plate 75, the third interposed plate 76, the fixing bracket 24 having the long hole 71, the clamp bracket 25, the suspension mechanisms T1, T2, the connecting / disengaging mechanism R, etc. It is configured.

(About column shrinkage)
As shown in FIG. 2, the steering device 1 of the present embodiment has a length of A to G before the column contraction.

A is a length until the end surface of the lower tube 14 on the side opposite to the housing 17 contacts the bearing 5 or the like.
B is a length until the end surface of the upper tube 13 on the housing 17 side hits a portion of the housing 17 where the torque sensor S is accommodated.

C is the length until the end surface of the lower shaft 12 on the side opposite to the housing 17 contacts the upper shaft 11.
D is a length until the end surface of the upper shaft 11 on the housing 17 side hits the enlarged diameter portion 12 b of the end portion of the lower shaft 12.

  E is a bracket that first hits when the suspension mechanisms T1 and T2 move in the column moving direction X1 among the brackets that constitute the torque sensor S of the housing 17 and the upper bracket 23. Is the length.

Which of A to E is the shortest depends on the specification of the steering device 1. In the example of FIG. 2, the length D is the shortest among A to E.
Here, when the suspension mechanisms T1 and T2 move within the range of the column contraction amount (EA stroke) described above, the taper portion 46 of the tilt spring 40 abuts on a portion of the housing 17 that houses the torque sensor S. Is arranged.

Note that F is a fitting length between the upper tube 13 and the lower tube 14, and G is a fitting length between the upper shaft 11 and the lower shaft 12.
(Operation of the embodiment)
Next, the steering device 1 configured as described above has an end portion in the axial direction of the collar 66 having a hardness (for example, metal) higher than that of the resin pin 64 and a metal clamp such as iron in a secondary collision. The peripheral edge of the through hole 89 of the bracket 25 functions as a pair of shearing blades to shear the resin pin 64 (shaft portion 87).

  As a result, the suspension mechanisms T1 and T2 move together with the clamp bracket 25 and the upper tube 13 in the column movement direction X1 (see FIGS. 1 to 3; the direction orthogonal to the paper surface in FIG. 4). During this movement, shock absorption is performed by friction between the first interposed plate 73 and the fixed bracket 24, friction between the second interposed plate 75 and the fixed bracket 24, and the like. Further, as a result of this movement, as shown in FIG. 2, the tapered portion 46 is disposed so as to face the housing 17, and therefore, when the steering column 6 contracts at the time of the secondary collision, the torque sensor of the tilt spring 40 and the housing 17 is provided. When the portion storing S is in initial contact (initial collision), both tapered portions 46 are expanded to absorb the impact.

  FIG. 9 is an explanatory diagram of a case where the part that houses the torque sensor S of the housing 17 is viewed as the interference object 100 with respect to the taper portion 46 of the tilt spring 40 when the steering column 6 contracts during a secondary collision. is there. As shown in the figure, when the interference object 100 collides with both tapered portions 46 of the tilt spring 40, both tapered portions 46 open in the vehicle width direction as shown by arrows in FIG. . Further, since the tapered portion 46 is tapered, both the tapered portions 46 can be easily opened in the vehicle width direction. For this reason, it is possible to prevent an impact load from standing (peaking) as compared with the case where the tilt spring 40 does not have the tapered portion 46.

  FIG. 10 is a characteristic diagram of shock absorption of the present embodiment when the horizontal axis is a stroke and the vertical axis is a load. The stroke is a stroke in which the steering wheel is displaced forward at the time of a secondary collision, and the load is a load required to displace the steering wheel in the forward direction.

  As shown in the figure, when the resin pin 64 is sheared in the necessary range of the EA stroke (that is, the length (distance) in which the column contraction amount is the shortest among A to E), In the end region in the range where the peak occurs and the interference object 100 collides with the taper portion 46, the load slightly increases to the right. The reason why the peak does not occur in the terminal region is that both the tapered portions 46 are opened, and the load can be dispersed, so that the load is smaller than that during shearing.

This embodiment has the following features.
(1) The tilt spring 40 of the steering device 1 of the present embodiment has an upper spring portion (a latching portion 54, a falling edge) in which the upper portion is connected to the upper bracket 23 (vehicle side bracket) and the lower portion extends forward of the vehicle. Part 52 and extension part 50). Further, the tilt spring 40 is connected to the lower part of the upper spring part and is bent to the rear of the vehicle (torsion part 48, taper part 46), and from the bending part (torsion part 48, taper part 46) to the steering column 6 below. And a lower spring portion (pressing action portion 44) that is disposed on the side and extends rearward of the vehicle. Further, the bent portion is provided with a tapered portion 46 that is tapered toward the front of the vehicle as viewed from above the vehicle, and the tapered portion 46 is used when the upper tube 13 moves relative to the lower tube 14. In addition, initial contact is made with the power assist unit.

  With this configuration, since the tapered portion 46 is tapered, it can be easily opened in the vehicle width direction, and an impact load can be prevented from standing compared to the case where the tilt spring 40 does not have the tapered portion 46. .

  (2) In this embodiment, the upper spring part, the bent part, and the lower spring part (pressing action part 44) are provided in pairs, and each of the pair of parts is arranged symmetrically with the lower spring part ( The pressing action part 44) is connected via a connecting part 42. As a result, at the time of the secondary collision, the interference object makes initial contact with the tilt spring, and the pair of taper portions 46 move in a direction to avoid the interference, so that the collision load can be reduced.

In addition, embodiment of this invention is not limited to the said embodiment, You may change as follows.
In the above-described embodiment, the steering device has a telescopic adjustment function. However, the steering device may be applied to an electric power steering device that does not have a telescopic adjustment function and has only a tilt adjustment function.

The shape of the tilt spring 40 is not limited as long as it has the tapered portion 46.
-The shape of the taper part 46 may correspond to the shape of the interference. It is possible to control the EA load by variously changing the shape of the interference. That is, in the present embodiment, the tapered portion 46 of the tilt spring 40 is made to correspond to the portion of the housing 17 that houses the torque sensor S. If the object that collides with the tilt spring 40 is other than the part that houses the torque sensor S of the housing 17, a tapered portion may be formed in accordance with the object.

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 3 ... Steering shaft, 5 ... Bearing,
6 ... Steering column, 11 ... Upper shaft, 11a ... Spline fitting part,
12 ... Lower shaft, 12a ... Spline fitting part, 12b ... Expanded part,
13 ... Upper tube (upper jacket),
14 ... Lower tube (lower jacket), 16 ... Output shaft, 17 ... Housing,
19, 20, 21 ... bearings, 22 ... worm wheel,
23 ... Upper bracket (vehicle side bracket), 24 ... Fixing bracket,
25 ... Clamp bracket,
26 ... Column bracket, 27 ... Hanging bolt, 28 ... Fastening shaft, 29 ... Side plate,
30 ... side plate, 31 ... connecting plate, 32 ... connecting plate, 33 ... spring mounting plate, 33a ... fixed recess,
33b ... Locking groove, 34 ... Nut, 35 ... Lock mechanism, 36 ... Operation lever 37 ... Sleeve, 38 ... Pressing part, 40 ... Tilt spring, 42 ... Connecting part,
44 ... Pressing action part (lower spring part), 46 ... Taper part (bending part),
48 ... Torsion part (bent part), 50 ... Extension part (upper spring part),
52 ... Falling part (upper spring part), 54 ... Hook part (upper spring part),
55 ... hook part, 60 ... leaf spring, 62 ... nut, 64 ... resin pin, 66 ... collar,
67 ... Flat plate portion, 68 ... Side plate, 70 ... Mounting plate, 71 ... Long hole, 72 ... Round hole,
73 ... 1st interposed plate, 74 ... Insertion hole, 75 ... 2nd interposed plate, 76 ... 3rd interposed plate,
77 ... Counter plate, 78 ... Connecting plate, 79 ... Counter plate, 80 ... Connecting plate, 81 ... Locking part,
82 ... head, 83 ... large diameter part, 84 ... screw part, 86 ... head, 87 ... shaft part,
100: Interfering object, A to F: Length, M: Motor, O ... Tilt center axis,
T1, T2 ... Hanging mechanism, R ... Connecting / disengaging mechanism.

Claims (2)

A tilt mechanism including a tilt spring coupled to a vehicle-side bracket and a steering column biased upward by the tilt spring;
The upper tube of the steering column is fitted so as to be slidable in the axial direction relative to the lower tube, and the upper tube together with the vehicle side bracket is moved relative to the lower tube at the time of a secondary collision. In an electric power steering apparatus including an impact absorbing mechanism that performs impact absorption and a power assist unit that is provided at a lower portion of the steering column and applies an assist force,
The tilt spring is
An upper spring portion having an upper portion coupled to the vehicle side bracket and a lower portion extending forward of the vehicle;
A bent portion connected to the lower portion of the upper spring portion and folded back toward the vehicle;
A lower spring portion disposed from the bent portion to the lower side of the steering column and extending rearward of the vehicle,
The bent portion includes a tapered portion that extends in a tapered shape toward the front of the vehicle as viewed from above the vehicle,
The taper portion is an electric power steering device that initially contacts the power assist portion when the upper tube moves relative to the lower tube.   The upper spring part, the bent part, and the lower spring part each include a pair, and the pair of parts are arranged symmetrically with respect to the steering column, and the lower spring part includes a connecting part. The electric power steering apparatus according to claim 1, wherein the electric power steering apparatus is connected via a via.