JP5169154B2 - Position adjustment type steering device - Google Patents

Description

  The present invention relates to a position-adjustable steering apparatus that adjusts a tilt position and a telescopic position by an electric drive mechanism.

  For example, many electric telescopic mechanisms convert the rotary motion of an electric motor into linear motion of a rod, and the steering column is contracted using this linear motion of the rod. Generally, conversion to linear motion is performed by a bearing. This is performed by a nut member that is rotationally driven by an electric motor while being rotatably held, and a rod that is screwed to the nut member while being prevented from rotating.

In order to ensure a smooth operation between these nut members and the rod and eliminate rattling, a resin nut member is adopted for the metal rod, and the thermal expansion coefficient of both is further increased. Paying attention to the difference, there was a slit provided at both ends of the nut member or the effective diameter of the female screw changed in the axial direction so that a good screwed state could be maintained even at low temperatures (see Patent Document 1). .
JP 2001-315648 A

By the way, if the interference between the bearing and the nut member is too large, the resin-made nut member may be deformed when press-fitted. This causes a decrease in driving efficiency. A certain degree of tolerance grade is required. However, since the resin nut member is injection-molded, there is a problem that it is difficult to obtain high dimensional accuracy.
It is an object of the present invention to increase the upper dimensional tolerance required for a nut member to facilitate its molding.

A position-adjustable steering apparatus according to a first aspect of the present invention is a position-adjustable steering apparatus that adjusts the position of a steering wheel by an electric drive mechanism, and the electric drive mechanism moves the position of the steering wheel by moving back and forth in the axial direction. An advancing / retracting rod that can be adjusted, a resin nut member having an inner circumference screwed to the outer circumferential surface of the advancing / retreating rod and a gear formed at the outer circumferential axial center , and both axial ends of the outer circumference of the nut member A bearing that is rotatably held by an inner ring, and a rotational drive source that meshes with the gear of the nut member and rotationally drives the nut member, and the nut member is provided on an outer peripheral surface that is press-fitted into the bearing. non-contact surface formed of a non-contact state with the inner ring of the bearing, in Rukoto formed along the axial direction, the circumferential direction of the outer peripheral surface that is press-fitted into the bearing Only a portion is in contact with the inner ring, a circumferential direction of the at least three positions, the non-contact surface is formed, characterized in Rukoto.

Position adjustable steering device according to claim 2 of the present invention, prior Symbol nut member, at equal intervals in the circumferential direction, characterized in that the non-contact surface is formed.

  According to the present invention, the non-contact surface with respect to the bearing is formed along the axial direction on the outer peripheral surface of the nut member, so that even when the interference between the bearing and the nut member is increased, the nut is The contact portion of the member with the bearing will escape to the non-contact surface side. That is, the excess in the radial direction can be released in the circumferential direction, and the press-fit load of the nut member can be reduced (relieved). Thus, since the above dimensional tolerance can be increased with respect to the outer diameter of the nut member, the required tolerance grade is lowered and the molding becomes easy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is an overall configuration of a steering apparatus, FIG. 2 is a side view of a steering column, FIG. 3 is a cross-sectional view taken along line AA of the steering column, FIG. 4 is a cross-sectional view taken along line BB of the steering column, and FIG. FIG. 6 is a longitudinal section of the steering column, FIG. 7 is a DD section of the electric telescopic mechanism, and FIG. 8 is a schematic configuration of the nut member.

  As shown in FIG. 1, in the steering device 1, a steering wheel 2 is connected to one end of a steering shaft 3, and the steering shaft 3 is rotatably held by a steering column 4. The other end of the steering shaft 3 is connected to the upper end of the intermediate shaft 6 via the universal joint 5, and the lower end of the intermediate shaft 6 is connected to the rack and pinion type steering gear 8 via the universal joint 7. Both ends of the rack are connected to the left and right tie rods 9, respectively, and the wheels 10 are steered by pushing and pulling the tie rods 9 according to the advance and retreat of the rack. Various switches 11 such as a combination switch and operation switches of an electric tilt mechanism 40 and an electric telescopic mechanism 70 described later are disposed in the vicinity of the steering wheel 2.

  As shown in FIG. 2, the steering column 4 has a cylindrical outer column 23 that is pivotally supported by the vehicle body member 22 in a state in which one end side can be swung by a tilt pivot 21, and one end in a state in which the steering column 4 can slide in the axial direction. The inner side of the outer column 23 is configured by a cylindrical inner column 24, and a telescopic steering shaft 3 is rotatably held inside the inner column 24. The other end side of the outer column 23 is clamped from both left and right sides by a substantially rectangular frame-shaped bracket 25 fixed to the vehicle body member 22 so as to be slidable in the vertical direction.

  The steering shaft 3 includes an input shaft 3a on one end side to which the steering wheel 2 is connected, and an output shaft 3b on the other end side that is fitted in the input shaft 3a, and both of them are relatively rotated by spline or serration. Blocked and axial relative displacement is allowed (see FIG. 6). Therefore, when the inner column 24 slides with respect to the outer column 23, the input shaft 3a and the output shaft 3b are displaced relative to each other in the axial direction, whereby the steering shaft 3 expands and contracts.

With the above configuration, the tilt position (vertical position) of the steering wheel 2 is determined by the swing angle of the outer column 23 around the tilt pivot 21, and the sliding position of the inner column 24 relative to the outer column 23 is The telescopic position (front / rear position) is determined.
As shown in FIG. 3, the bracket 25 is connected to the top plate 25a, a pair of guide plates 25b and 25c suspended from the left and right sides of the top plate 25a, and the lower ends of the guide plates 25b and 25c. A bottom plate 25d, and a flange 25e (25f) that projects from the upper portion of the guide plate 25b (25c) and engages and is fixed to the upper surface of the vehicle body member 22.

  An end surface 23b facing the guide plate 25b and an end surface 23c facing the guide plate 25c are formed in the outer column 23 along the axial direction, and a backlash filling plate 26 is provided between the guide plate 25b and the end surface 23b. Is intervening. In the guide plate 25b, adjustment bolts 27 are screwed into two upper and lower through holes 25g, and the tips of the adjustment bolts 27 are engaged (contacted) with the backlashing plate 26 in a rotatable state. The adjustment bolt 27 is fastened to the guide plate 25b by a set nut 28. In addition, while forming a convex part in the front-end | tip of the adjustment bolt 27 and forming the recessed part engaged with this convex part in the backlash filling plate 26, the backlash filling plate 26 is positioned and an assembly | attachment becomes easy.

  With the above configuration, when the adjusting bolt 27 is screwed after loosening the locking nut 28, the back column plate 26 presses the outer column 23 toward the guide plate 25c. Shaking is suppressed. However, the screwing amount of the adjusting bolt 27 is adjusted so that the sliding resistance of the end surface 23b with respect to the backlash plate 26 and the sliding resistance of the end surface 23c with respect to the guide plate 25c are smaller than the driving force of the electric tilt mechanism 40 described below. And then fastened with a lock nut 28.

As shown in FIG. 2, the bracket 25 is provided with an electric tilt mechanism 40 that adjusts the tilt position by electric drive, and the outer column 23 is provided with an electric telescopic mechanism 70 that adjusts the telescopic position by electric drive.
As shown in FIGS. 4 and 5, the electric tilt mechanism 40 includes a screw shaft 41 disposed in the vertical direction along the guide plate 25 c, an electric motor 42 that rotationally drives the screw shaft 41, and a screw shaft 41. A nut 43 that is screwed and prevented from rotating and an engagement pin 44 that engages the nut 43 with the outer column 23 are provided.

  As shown in FIG. 4, the screw shaft 41 has a lower end pivotally supported by a bearing 52 in a gear housing 51 connected to the lower portion of the guide plate 25c, and an upper end fixed to a lower surface of the flange 25f. It is pivotally supported by. In the gear housing 51, a worm wheel 54 is coupled to the screw shaft 41, and a worm shaft 55 is engaged with the worm wheel 54.

As shown in FIG. 5, the worm shaft 55 is pivotally supported by bearings 56 and 57 in the gear housing 51, and is connected to the rotating shaft 42 a of the electric motor 42 through a coupling 58.
As shown in FIG. 4, the nut 43 is provided with a nut holder 61 that prevents relative displacement in the circumferential direction. The nut holder 61 is prevented from rotating by engaging with the end face of the guide plate 25c. ing. An engaging pin 44 is projected from the nut holder 61, and its tip is engaged with an elongated hole 23 d formed in the outer wall surface of the outer column 23.

The lower side of the screw shaft 41 is covered with a cylindrical cover 62 fixed to the gear housing 51. The upper surface of the cylindrical cover 62 and the lower surface of the bearing 53 are each formed of a synthetic resin such as polyurethane. A damper member 63 slidably contacting the screw shaft 41 is disposed.
With the above configuration, when the screw shaft 41 rotates in accordance with the forward rotation (or reverse rotation) of the electric motor 42, the nut 43 that is prevented from rotating rises (or descends), and the vertical movement of the nut 43 causes the engagement pin to move upward and downward. It is transmitted to the outer column 23 via 44. At this time, the engagement pin 44 draws a linear trajectory in the vertical direction, whereas the outer column 23 draws a rotation trajectory centered on the tilt pivot 21, but the engagement pin 44 extends along the long hole 23 d. By sliding, the difference between both trajectories is absorbed. Thus, the swing angle of the outer column 23 is adjusted according to the vertical movement of the nut 43.

  As shown in FIGS. 6 and 7, the electric telescopic mechanism 70 is offset and arranged in parallel with the outer column 23, and is made of a metal advance / retreat rod 71 having a male thread portion 71a formed on one end side (tilt pivot 21 side); A resin nut member 72 screwed into the male screw portion 71a and prevented from axial displacement in a rotatable state, an electric motor 73 that rotationally drives the nut member 72, and the other end side of the advance / retreat rod 71 And a connecting member 74 that connects the inner column 24 and prevents the advance / retreat rod 71 from rotating.

As shown in FIG. 6, the nut member 72 is pivotally supported by bearings 82 and 83 in a gear housing 81 fixed to the lower surface of the outer column 23, and a helical gear 72a is formed on the outer periphery thereof. The worm shaft 84 meshes with 72a.
As shown in FIG. 8, the nut member 72 has a non-contact surface 72 b which is in a non-contact state with a predetermined gap with respect to the bearings 82 and 83 on the outer peripheral surface press-fitted into the bearings 82 and 83. It is formed along the direction. That is, only a part of the outer peripheral surface in the circumferential direction is brought into contact with the bearings 82 and 83. The non-contact surface 72b is composed of a plane along a string connecting both ends of the arc, and is formed at equal intervals in four locations in the circumferential direction.

As shown in FIG. 7, the worm shaft 84 is pivotally supported by bearings 85 and 86 in the gear housing 81, and is connected to the rotating shaft 73 a of the electric motor 73 through a coupling 87.
With the above configuration, when the nut member 72 rotates according to the forward rotation (or reverse rotation) of the electric motor 73, the forward / backward rod 71 that is prevented from rotating moves forward (or reverse). Since the advance / retreat of the advance / retreat rod 71 is transmitted to the inner column 24 by the connecting member 74, the inner column 24 extends (or contracts) relative to the outer column 23. Thus, the sliding position of the inner column 24 relative to the outer column 23 is adjusted according to the advance / retreat of the advance / retreat rod 71.

Since the electric tilt mechanism 40 and the electric telescopic mechanism 70 employ a worm gear structure having irreversible characteristics, the tilt position and the telescopic position change even if a vertical load or a longitudinal load is input to the steering wheel 2. Never do.
Next, the function and effect of the embodiment will be described.
It is assumed that the outer diameter dimension of the resin nut member 72 is larger than the reference dimension and the interference between the bearings 82 and 83 is increased. However, the non-contact surface 72b with respect to the bearings 82 and 83 is formed on the outer peripheral surface of the nut member 72 along the axial direction, so that the contact portion of the nut member 72 with the bearings 82 and 83 is non-contact when press-fitted. Escape to the surface 72 side. In other words, the remainder in the radial direction can be released in the circumferential direction, and the press-fit load of the nut member 72 can be reduced (relieved). Therefore, since the radial deformation of the nut member 72 is suppressed, it is possible to maintain a good screwed state with the male screw portion 71a and prevent a decrease in driving efficiency. As described above, since the above dimensional tolerance can be increased with respect to the outer diameter of the nut member 72, the required tolerance grade is lowered and the molding becomes easy. Further, the lower dimensional tolerance can be increased for the inner diameter dimensions of the bearings 82 and 83.

Further, by forming the non-contact surfaces 72b at equal intervals in the circumferential direction of the nut member 72, the coaxiality (concentricity) between the nut member 72 and the bearings 82 and 83 can be maintained.
In the above embodiment, the non-contact surfaces 72b are formed at the four circumferential positions of the nut member 72, but the present invention is not limited to this. That is, as shown in FIG. 9, the non-contact surface 72b may be formed at three or five locations in the circumferential direction, and if formed at at least three locations in the circumferential direction in this way, the nut member 72 and the bearing 82 are formed. , 83 can be maintained. Of course, the press-fitting load of the nut member 72 can be reduced only by forming it at one place or two places in the circumferential direction.

  In the above embodiment, the non-contact surface 72b is formed along the string connecting both ends of the arc. However, the present invention is not limited to this. In short, it is only necessary to form a non-contact surface 72b that is in a non-contact state with respect to the bearings 82 and 83. Therefore, as shown in FIG. It is good also as forming along a direction and making the other outer peripheral surface (cylindrical surface) the non-contact surface 72b. In this case, since the bulging portion 72c comes into contact with the bearings 82 and 83, when press-fitted, the excess in the radial direction of the bulging portion 72c is released in the circumferential direction, and the press-fitting load of the nut member 72 is reduced. be able to.

  In the above-described embodiment, the present invention is applied to the nut member 72 included in the electric telescopic mechanism 70. However, the present invention is not limited to this. That is, even in the electric tilt mechanism 40, the present invention can be applied to this nut member as long as the forward / backward rod is advanced / retracted by the rotation of the nut member and the swing angle of the outer column 23 is adjusted thereby. it can.

It is the whole structure of a steering device. This is the side of the steering column. It is an AA cross section of a steering column. It is a BB cross section of a steering column. It is CC cross section of an electric tilt mechanism. It is a longitudinal section of a steering column. It is DD cross section of an electric telescopic mechanism. It is a schematic structure of a nut member. It is an example of formation of a non-contact surface. It is a modification of a non-contact surface.

Explanation of symbols

  2 ... steering wheel, 3 ... steering shaft, 3a ... input shaft, 3b ... output shaft, 21 ... tilt pivot, 22 ... body member, 23 ... outer column, 23d ... long hole, 24 ... inner column, 25 ... bracket, 25b ... Guide plate, 25c ... Guide plate, 25g ... Through hole, 26 ... Roughing plate, 27 ... Adjustment bolt, 28 ... Set nut, 40 ... Electric tilt mechanism, 41 ... Screw shaft, 42 ... Electric motor, 43 ... Nut, 44 ... engaging pin, 70 ... electric telescopic mechanism, 71 ... advance / retreat rod, 72 ... nut member, 72b ... non-contact surface, 72c ... bulge part, 73 ... electric motor, 74 ... connecting member, 82 ... bearing, 83 ... bearing

Claims (2)

A position-adjustable steering device that adjusts the position of a steering wheel by an electric drive mechanism,
The electric drive mechanism includes an advancing / retreating rod that can adjust the position of the steering wheel by advancing / retreating in the axial direction, and a resin nut member having an inner periphery screwed into the advancing / retracting rod and a gear formed in the axial center of the outer periphery. And a bearing that holds both axial ends of the outer periphery of the nut member in a rotatable state by an inner ring, and a rotational drive source that meshes with the gear of the nut member and rotationally drives the nut member,
The nut member has an outer peripheral surface which is press-fitted into the bearing, non-contact surface formed of a non-contact state with the inner ring of the bearing, in Rukoto formed along the axial direction, is press-fitted into the bearing only a portion of the circumferential direction of the outer peripheral surface is in contact with the inner ring, a circumferential direction of the at least three positions, the non-contact surface is formed a position adjustable steering device according to claim Rukoto.   The position adjusting type steering apparatus according to claim 1, wherein the nut member is formed with the non-contact surface at equal intervals in a circumferential direction.

Images