JPH0710997Y2 - Electric tilt steering device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric tilt steering device for an automobile or the like.

In the electric tilt steering device of this type, a tilt bracket is swingably attached to a fixed bracket fixed to a vehicle body, and the tilt bracket is attached by rotation of a tilt motor attached to the fixed bracket side. Is to be swung. The fixed bracket supports the lower steering shaft via the lower column, and the tilt bracket supports the upper steering shaft via the upper column. The lower steering shaft and the upper steering shaft are connected by a universal joint, and the center of the universal joint is on the swing center line of the tilt bracket. A steering wheel is attached to the upper end of the upper steering shaft. Then, the position of the steering wheel can be changed by driving the electric motor to swing the tilt bracket.

As such a tilt steering device, the applicant of the present invention has found that a screw shaft mounted on the fixed bracket side and rotated by an electric motor, a screw nut engaged with the screw shaft, and an eccentricity that swingably connects the screw nut and the tilt bracket. We have proposed a device with a member (see Japanese Patent Application No. 62-156632). A part of the screw nut is divided into two by a slit, and the preload with the screw shaft is adjusted by tightening this part with a bolt and a nut. Pins are integrally formed on both sides of the screw nut on an axis substantially orthogonal to the axis of the screw shaft,
An eccentric member is rotatably attached to these pins via needle roller bearings. The eccentric member is rotatably attached to the tilt bracket via a ball bearing.

However, this tilt steering device has the following problems.

That is, as described above, the preload with the screw shaft is adjusted by adjusting the clearance of the slit part divided into two of the screw nuts, but by this, it is integrally formed on both sides of the screw nut. The fallen pin will fall. Since the needle roller bearing cannot be assembled as it is, conventionally, after adjusting the clearance of the slit portion of the screw nut, the pin portion is ground to correct the fall. Therefore, the number of assembling and processing steps is increased, and the cost is increased.

If pins are formed on both sides of the screw nut on the opposite side of the slit with respect to the axis of the screw shaft, it is possible to prevent the pins from falling over even if the clearance of the slit is adjusted. it can. However, in this case, the axis line of the screw shaft for driving the screw nut and the axis line of the pin connected to the tilt bracket are separated from each other, and therefore, when the screw shaft is driven by rotating the screw shaft. However, there is a problem that the screw nut is tilted, and the movement of the screw nut, that is, the tilting operation is not smooth. Therefore, as described above, the pins are formed on both sides of the screw nut on the axis substantially orthogonal to the axis of the screw shaft, and the pins are connected to the tilt bracket on the axis substantially orthogonal to the axis of the screw shaft. Drives the screw nuts smoothly.

An object of the present invention is to provide an electric tilt steering device that solves the above problems.

Means for Solving the Problems An electric tilt steering device according to the present invention includes a fixed bracket that is fixed to a vehicle body and supports a lower steering shaft through a lower column, and a lower steering shaft that is swingably attached to the fixed bracket by a universal joint. A tilt bracket for supporting the upper steering shaft connected to the upper bracket via the upper column, a tilt motor mounted on the fixed bracket side, and a conversion means for converting the rotation of the motor into the swing of the tilt bracket. In the tilt steering apparatus, the conversion means includes a screw shaft attached to the fixed bracket side and connected to the electric motor, a screw nut engaged with the screw shaft, and an eccentric member for swingably connecting the screw nut and the tilt bracket. The screw nut is divided into two parts by the slit, and the preload with the screw shaft is adjusted by tightening this part, and it is almost orthogonal to the axis of the screw shaft on both sides of the screw nut. Pins are integrally formed on the shaft, the eccentric member is rotatably attached to these pins via a spherical bush, and the eccentric member is rotatably attached to the tilt bracket side. is there.

The eccentric member may be attached to the tilt bracket side via a rolling bearing.

Action Since pins are formed on both sides of the screw nut on an axis that is substantially orthogonal to the axis of the screw shaft,
The pin is connected to the tilt bracket on an axis that is substantially orthogonal to the axis of the screw shaft, so that the screw nut can be driven smoothly by the screw shaft.

Even if the pin is tilted by adjusting the clearance of the slit portion of the screw nut, the tilt is absorbed by the spherical bush. Therefore, the pin can be polished before the above adjustment.

Embodiments Embodiments in which the present invention is applied to an electric tilt steering device of a vehicle will be described below with reference to the drawings. In the following description, the left side of FIGS. 1 and 2 is the front, the right side is the rear, the lower side of FIG. 1 is the left side, and the upper side is the right side.
The top and bottom of FIG. 2 are referred to as the top and bottom.

1 to 8 show the first embodiment.

A fixed bracket (1) is fixed to a vehicle body (not shown) of an automobile. The fixing bracket (1) has a substantially U shape with an open rear when viewed from above, and a lower column (2) is provided at the front end thereof.
Is fixed. The front end portion of the lower column (2) is also fixed to the application portion of the vehicle body by the fixing member (3).
A lower steering shaft (lower shaft) (4) is rotatably supported in the lower column (2). Although illustration is omitted, the front end of the lower shaft (4) is connected to the steering gear.

The rear portion of the tilt bracket (5) is swingably attached to the rear portion of the fixed bracket (1) by two connecting pins (special bolts) (6) extending left and right. The tilt bracket (5) has a substantially U shape with its front part opened when viewed from above, and the left side portion (5a) is outside (left side) the left side portion (1a) of the fixed bracket (1) and the right side portion (5b). Are arranged inside (left side) of the right side portion (1b) of the fixed bracket (1). An upper column (7) is fixed to the rear end of the tilt bracket (5), and an upper steering shaft (upper shaft) (8) is rotatably supported in the upper column (7). At the rear end of the upper shaft (8), there is a steering wheel (9).
Is installed. The front end of the upper shaft (8) is connected to the rear end of the lower shaft (4) via a universal joint (10), and the center of this universal joint (10) is the swing center of the tilt bracket (5). That is, it is on the center line (6c) of the connecting pin (6). Further, a tension coil spring (11) for biasing the tilt bracket (5) in an upward swinging direction is mounted between the front portion of the upper surface of the fixed bracket (1) and the rear portion of the upper surface of the tilt bracket (5). There is. Although illustration is omitted, if necessary, the upper column (7) is provided with a telescope driving unit for expanding and contracting the upper shaft (8).

A housing (12) is fixedly provided on the outer surface of the left side portion (1a) of the fixed bracket (1). Both ends of a screw shaft (13), which extends approximately in the vertical direction, are rotatably supported at the rear of the housing (12) via ball bearings (14) (15). On the upper surface of the front wall of the housing (12), the tilting motor (16) is fitted with a screw shaft (1
It is fixed downwards so that it is parallel to 3).
The motor shaft (17) penetrates the wall of the housing (12) and projects downward, and the small pulley (18) is fixed to this portion. A large pulley (27) and a small pulley (28) are integrally connected by a collar (19) and a pin (not shown) to a portion of the housing (12) between the screw shaft (13) and the electric motor (16). An intermediate pulley assembly (60) is rotatably attached to a base plate (22) by a bolt (20) and a nut (21), and the base plate (22) is attached by a bolt (23) to an elongated hole (25). ) Utilizing housing (12)
The position is fixed so that it can be adjusted. A large pulley (29) is fixed to the lower part of the screw shaft (13). Small pulley (18) and intermediate pulley assembly (60) for electric motor (16)
The timing belt (30) is hung on the large pulley (27), and the timing belt (31) is hung on the small pulley (28) of the intermediate pulley assembly (60) and the large pulley (29) of the screw shaft (13). ing.

Screw shaft (13) with screw nut (32)
Are intermeshed. The screw nut (32) has a substantially rectangular parallelepiped shape, the rear part of which is divided into two by the slit (61). By tightening this part with the bolt (33) and the nut (34), preload with the screw shaft (13) is performed. Has been adjusted. The front end of the left side portion (5a) of the tilt bracket (5) is located immediately to the right of the screw nut (32). On the outer surface of the left side portion (5a) of the tilt bracket (5) near the front end, a cylindrical spacer (3
The arm (37) is fixed at a distance by means of the bolt (36) and the bolt (5), and this arm (37) is located immediately to the left of the screw nut (32). Pins (38) are integrally formed on the left and right sides of the screw nut (32) on the left and right axes substantially orthogonal to the axis of the screw shaft (13), and the spherical bushes (39) are inserted into these pins (38). The eccentric disc (40) is rotatably attached.
Ball bearings (41) are attached to the eccentric disc (40), and these ball bearings (41) are provided with holes (62) () formed in the left part (5a) of the tilt bracket (5) and the arm (37). 63)
It is fitted inside the. As will be described later, the eccentric disc (40) has linear movement of the screw nut (32) and the left side portion (5a) of the tilt bracket (5) and the arm (3).
This is to absorb the difference of the locus with the circular motion of 7).

The limit switch (LS) actuation plate (42) is fixed to the front end of the right side portion (5b) of the tilt bracket (5), and the position sensor actuation piece (43) is fixed near the pin (6) so that the position can be adjusted. ing. On the inner surface of the right side portion (1b) of the fixed bracket (1), a pair of stoppers (44) (45) for the right side portion (5b) of the tilt bracket (5) and a pair of corresponding LS actuating plates (42). The position sensor (48) corresponding to the LS (46) (47) and the position sensor actuating piece (43) is fixed. The stoppers (44) (45) are rubber (49) with washers (50) and deformation bolts (51) fixed on both sides.
The upper stopper (44) regulates the tilt upper end position of the tilt bracket (5), and the lower stopper (45) regulates the tilt lower end position of the tilt bracket (5). The upper LS (46) detects the upper end position of the tilt bracket (5), and the lower LS (47) detects the lower end position of the tilt bracket (5). The position sensor (48) is, for example, a potentiometer that converts the movement of the actuator (52) in pressure contact with the actuating piece (43) into an electric signal, and detects the tilt angle of the tilt bracket (5). The output signal of the position sensor (48) is used when, for example, the normal use position of the steering wheel (9) is stored and the control is automatically set to this position.

In the above tilt steering device, the electric motor (16)
The rotation of the timing belt (30) (31) and pulley (1
8) (27) (28) (29) is decelerated and transmitted to the screw shaft (13), whereby the screw nut (32) moves up and down along the screw shaft (13). Then, the vertical movement of the screw nut (32) is converted into swing of the tilt bracket (5) via the eccentric disc (40), and the steering wheel (9) tilts vertically. As shown in FIG. 8, the vertical movement of the screw nut (32) is a linear motion, and the swinging of the tilt bracket (5) is a circular motion centered on the center line (6c) of the connecting pin (6). However, as the screw nut (32) moves, the center line (40c) of the eccentric disc (40) comes in an arc shape centered on the center line (6c) of the connecting pin (6). By rotating the (40) around the center line (38c) of the pin (38), the difference between these trajectories is absorbed,
The linear movement of the screw nut (32) is converted into the swing of the tilt bracket (5). At this time, the tilt angle of the tilt bracket (5) is detected by the position sensor (48), and the LS (46) (47) is operated,
The tilt bracket (5) is stopped at the upper end position or the lower end position. And position sensor (48) and LS (4
6) Even if the tilt bracket (5) cannot be accurately stopped at the upper end position and the lower end position due to damage to the tilt bracket (5), the tilt bracket (5) will not stop.
4) Stop at (45). For this reason, the screw nut (32) does not have a problem such as being caught in the screw end portion of the screw shaft (13). Further, since the rotation of the electric motor (16) is converted into the swing of the tilt bracket (5) by the screw shaft (13) and the screw nut (32), the lead angle α of the screw of the screw shaft (13) and the screw meshing portion. If the friction coefficient μ is designed so that tan α <μ, the screw shaft (13) will not reverse even if a vertical load is applied to the steering wheel (9). In addition, the electric motor (1
Since the rotation of 6) is transmitted to the screw shaft (13) by the belts (30) and (31), the operating noise is low, and the accuracy of the distance between the pulley axes may be relatively poor, enabling mass production. The cost can be reduced.

As described above, by moving the screw nut (32),
Eccentric disc (40) is screw nut (32) pin (38)
Rotate around. Screw nut (32) pin (3
8) is tilted in the direction shown by the arrow (A) in FIG. 7 when the bolt (33) and nut (34) are tightened as described above, and they fall and become out of alignment. However, even in such a case, the fall is spherical bush (39)
Absorbed by. Therefore, the pin (38) can be polished before the above adjustment.

FIG. 9 shows a second embodiment.

In this case, the disc (66) having spherical concentric holes is directly attached to the left side portion (5a) of the tilt bracket (5) and the holes (62) (63) of the arm (37) without using the rolling bearing. There is. The spherical bush (65) having the eccentric hole is fitted in the inner diameter of the disc (66), and the pin (38) is fitted in the eccentric hole of the spherical bush (65).

Since the rotation of the spherical bush (65) with respect to the tilt bracket (5) due to the movement of the screw nut (32) is slight, this does not cause any problem.

Others are the same as in the case of the first embodiment, and the same parts are denoted by the same reference numerals.

Effect of the Invention According to the electric tilt steering device of the present invention, as described above, the screw nut is smoothly driven by the screw shaft, and moreover, the pin falls down due to the adjustment of the clearance of the slit portion of the screw nut. However, since it is absorbed by the spherical bushing, the pin can be ground before the above adjustment. Therefore, the tilting operation is smooth, and the man-hours for assembling and processing are reduced, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of an essential portion of an electric tilt steering device showing a first embodiment of the present invention, FIG. 2 is a side view of the partially cutout, and FIG. 3 is a line III-III of FIG. Enlarged sectional view, FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 2, FIG. 5 is a sectional view taken along line VV in FIG. 3, and FIG. 6 is an enlarged sectional view taken along line VI-VI in FIG. FIG. 7 is an enlarged sectional view taken along line VII-VII of FIG. 5, FIG. 8 is a side view for explaining the operation of the eccentric disc, and FIG. 9 is a drawing corresponding to FIG. 7 showing the second embodiment. (1) …… Fixing bracket, (2) …… Lower column,
(4) …… Lower steering shaft, (5) …… Tilt bracket, (7) …… Upper column, (8) …… Upper steering shaft, (10) …… Universal joint, (1
3) …… Screw shaft, (16) …… Tilt motor, (32) …… Screw nut, (38) …… Pin,
(39) …… Spherical bush, (40) …… Eccentric disc, (41)…
… Ball bearings (61) …… Slits.

Claims (2)

[Scope of utility model registration request] 1. A fixed bracket fixed to a vehicle body to support a lower steering shaft via a lower column, and an upper steering shaft swingably mounted on the fixed bracket and connected to the lower steering shaft by a universal joint via the upper column. In the electric tilt steering device including a tilt bracket for supporting the tilt bracket, a tilting electric motor mounted on the fixed bracket side, and a converting means for converting the rotation of the electric motor into the swinging of the tilt bracket, the converting means is fixed. It is equipped with a screw shaft attached to the bracket side and connected to the electric motor, a screw nut that meshes with the screw shaft, and an eccentric member that swingably connects the screw nut and the tilt bracket. Divided into two The preload with the screw shaft is adjusted by breaking this part and tightening this part, and pins are integrally formed on both sides of the screw nut on the axis substantially orthogonal to the axis of the screw shaft. An electric tilt steering device, wherein an eccentric member is rotatably attached via a spherical bush, and the eccentric member is rotatably attached to the tilt bracket side. 2. The electric tilt steering device according to claim 1, wherein the eccentric member is attached to the tilt bracket side via a rolling bearing.