JP2006168559A - Vehicular variable steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular variable steering device capable of increasing the turning angle when the steering angle is increased without using any rack of irregular pitch. <P>SOLUTION: The vehicular variable steering device to perform the steering by changing the direction of wheels by operating a tie rod and to increase the turning angle when the steering angle is increased comprises rack shafts 202, 212 provided with a helical rack and linked to a tie rod, helical pinions 301, 311, 361 which are engaged with the helical rack, and supported movably in the axial direction, and provided with the steering rotational force to move the rack shafts in the axial direction, and pinion guide mechanisms 304-307 operated to move the helical pinion in the axial direction according to the rotation of the helical pinion. The rack-pinion system may be changed to the worm-worm wheel system, or the screwed rack system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle steering apparatus, and more particularly to a variable steering apparatus in which a turning angle increases in a region where a steering angle is large.

  In general, the steering of the vehicle is configured such that the turning angle changes in proportion to the operation angle to change the direction of the vehicle. For example, when the steering wheel rotates once compared to when it rotates halfway, the steering angle, that is, the angle at which the direction actually changes, is doubled.

  9 and 10 show a conventional rack and pinion type and worm and worm wheel type steering mechanism. In the rack and pinion system shown in FIG. 9, the direction of the wheel is changed by moving the rack 2a connected to the wheel 1 in the axial direction by the pinion 3a connected to a steering hole (not shown). ing. The worm and pinion system shown in FIG. 10 has a mechanism for changing the direction of the wheels in the same manner, although the rack 2 in FIG. 9 is replaced with the worm 2b and the pinion 3a is replaced with the worm wheel 3b.

  Here, since the steering angle is increased when the direction of the vehicle is suddenly changed, the operational feeling can be improved if the turning angle can be made larger than the operation angle. In addition, the driver's fatigue is reduced, and safe and comfortable driving, particularly high-speed driving is possible.

Such a steering device can be realized by using a variable gear ratio mechanism as disclosed in Patent Document 1.
Japanese Patent Publication No. 4-3356

  However, since the variable gear ratio mechanism uses racks with unequal pitches, the production thereof is complicated and the cost is increased. As a result, it is in a situation where it is implemented only in some car models.

  The present invention has been made in consideration of the above-described points, and an object of the present invention is to provide a variable steering device for a vehicle in which the turning angle increases as the steering angle increases without using an unequal pitch rack. To do.

In order to achieve the above object, in the present invention,
A variable steering apparatus for a vehicle that steers by changing the direction of a wheel by operating a tie rod, wherein a helical rack is provided in the variable steering apparatus in which a turning angle increases when a steering angle increases. A linked rack shaft, a helical pinion that engages with the helical rack and is supported so as to be movable in the axial direction, and is provided with a steering rotational force to move the rack shaft in the axial direction, and to rotate the helical pinion And a pinion guide mechanism for operating the helical pinion to move in the axial direction according to the variable steering device for a vehicle,
A variable steering device for a vehicle that steers by changing the direction of a wheel by operating a tie rod, wherein the steering angle increases when the steering angle increases. A worm shaft that is rotatably linked to the worm, a worm wheel that engages with the worm and is operated to rotate and axially move the worm shaft by applying a steering operation force; and an axial direction of the worm A variable steering device for a vehicle characterized by having a worm shaft guide mechanism for applying a rotational force to the worm shaft as it moves, and a vehicle for steering by changing the direction of wheels by operating a tie rod In a variable steering device in which the turning angle increases as the steering angle increases, A screw shaft linked to the tie rod, a rack formed on at least a part of the outer periphery, a movable body with a rack screwed to the screw shaft, and a movable body with the rack supported to prevent rotation And a guide mechanism that engages with the follower and regulates rotation of the screw shaft as the follower moves in the axial direction. Variable steering device for vehicle,
Is to provide.

  As described above, according to the present invention, when the steering rotational force is transmitted to the wheels, the turning angle is increased in a range where the steering angle is large, so that the direction of the vehicle can be changed more quickly and the operability can be improved. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 (a) is a perspective view showing a main part of one embodiment of the present invention, showing only a part by a rack and pinion system, and omitting a part connected to a wheel.

  That is, a rack shaft 202 having a helical rack 201 with an equal pitch connected to a tie rod (not shown) and supported so as to be movable in the left-right direction is moved to the support member 101 fixed to the vehicle, and the helical rack 201 is moved in the axial direction. A pinion shaft 302 having a helical pinion 301 at the lower end in the figure is supported so as to be rotatable and axially movable.

  The pinion shaft 302 is connected to the steering shaft 303 via an intermediate member, and rotates in accordance with a rotation operation of a steering wheel (not shown) and moves in the axial direction.

  The intermediate member includes a spline joint 304, a spline 305 fixed to the upper end of the pinion shaft 302 in the figure, a rotation guide 306, and a guide member 307. The spline joint 304 is fixed to the lower end of the steering shaft 303 in the figure, and meshes with the spline 305 fixed to the upper end of the pinion shaft 302 in the figure. The rotation guide 306 is fixed at an intermediate position of the pinion shaft 302, the guide member 307 is fixed at the upper end of the support member 101 in the figure, and the rotation guide 306 is provided on the guide member 307. It moves along the groove and functions as a cam mechanism.

  The combination of the spline joint 304 and the spline 305 allows the pinion shaft 302 to rotate and move in the axial direction, and the rotation guide 306 and the guide member 307 form both the movement in the axial direction associated with the rotation and rotation.

  FIG. 1B shows the front shape of the rotation guide 307. A spiral groove is formed in the rotation guide 307, and the rotation guide 306 fixed to the pinion shaft 302 moves along this groove. As a result, the pinion shaft 302 moves in the axial direction as it rotates.

  In this configuration, when a steering wheel (not shown) is rotated, a rotational force is transmitted to the rotation guide 306 via the steering shaft 303, the spline joint 304, the spline 305, and the pinion shaft 302.

  Thereby, the rotation guide 306 moves along the spiral groove provided in the guide member 307. At this time, the pinion shaft 302 to which the rotation guide 306 is fixed receives the rotational force and the axial movement force, and transmits both to the helical pinion 301.

  The rotational force and axial movement force of the helical pinion 301 are transmitted to the helical rack 201, and the helical rack 201 is moved in the left-right direction (axial direction) in the figure according to the rotational force, and the helical pinion 301 is moved by the axial movement force. Since the different positions of the teeth in the axial direction mesh with the teeth of the helical rack 201, the meshing positional relationship between them is changed.

  This meshing positional relationship can be selected as appropriate according to the design of the teeth of the helical pinion 301 and the helical rack 201, and the meshing relationship can be changed either large or small depending on the size of the helical state. Then, assuming that the rack shaft 202 is moved in one of the horizontal directions in the figure, for example, when the helical pinion 302 is moved in the right direction in the figure, the helical pinion 301 is rotated counterclockwise (θ1 direction).

  At this time, the rotation guide 306 moves in the counterclockwise direction (θ2 direction) in the left direction in the figure through the spiral groove of the guide member 307. Therefore, the pinion shaft 302 is pulled upward in the figure, and the lower part of the helical pinion 301 is engaged with the helical rack 201.

  The inclination of the spiral groove of the guide member 307 determines the change in meshing between the helical pinion 301 and the helical rack 201. That is, the degree of change in the amount of movement of the rack shaft 202 varies depending on the degree of inclination of the spiral groove of the guide member 307.

  Therefore, the change degree of the turning angle can be determined by appropriately determining the degree of inclination of the spiral groove of the guide member 307. If the inclination of the spiral groove is designed linearly, the turning angle changes in proportion to the rotational operation angle of the steering wheel, and if it is made non-linear, the turning angle is non-linear with respect to the rotational operation angle. Will change.

  FIG. 2 shows a mechanism portion in the second embodiment of the present invention. In this embodiment, a cylindrical rack 316 is used instead of the rotation guide 306 and the guide member 307 which are the turning angle changing mechanism in the embodiment of FIG. The cylindrical rack 316 is provided with a moving force in the axial direction by a combination of the gear 318a and the motor 318b, and moves the pinion shaft 311 in the axial direction.

  Accordingly, when the steering wheel operating angle exceeds a predetermined value, the motor 318b is driven to move the cylindrical rack 316 in the axial direction so that the helical rack 211 can be engaged with the pinion 311 at different positions.

  FIG. 3 (a) shows a mechanism portion in the third embodiment of the present invention. In this embodiment, instead of the rack and pinion mechanism in the first and second embodiments, a worm / worm wheel mechanism using a worm connected to a tie rod and a worm wheel connected to a steering wheel is used. A turning angle changing mechanism is provided on the worm side.

  In order to connect the worm 221 to the tie rod, a pair of left and right ball joints 222 is provided, and a rotation guide 223 that functions as a cam mechanism is provided in the vicinity of one of the ball joints 222, at a position facing the rotation guide 223. Guide pins 224 are arranged. In the following embodiments, different reference numerals are given, but the mechanism for connecting to the tie rod has the same configuration.

  The worm 221, the worm wheel 321 that engages with the worm 221 and the guide pin 224 are supported by the support member 121, the worm 221 and the worm wheel 321 are rotatably supported, and the guide pin 224 is fixedly installed.

  3B shows the structure of the rotation guide 223 of the guide shaft, and FIG. 3C shows the structure of the guide member 224 as perspective views from different angles.

  In this case, the rotation angle of the worm wheel 321 and the rotation angle of the worm 221 are in a proportional relationship, and the worm wheel 321 rotates according to the rotation operation angle of the steering wheel in the θ1 direction and meshes with the worm wheel 321. The worm 221 moves in the axial direction, for example, in the left direction in the figure.

  As a result, the rotation guide 223 of the guide shaft also moves in the left direction in the figure, and when the variable guide surface of the rotation guide 223 is slid while being regulated by the guide member 224, a rotational force in the φ1 direction acts on the rotation guide 223. This is the action of rotating the worm 221 in the φ1 direction, and therefore promotes the rotation of the steering wheel in the θ1 direction. That is, the steering operation according to the operation of the steering wheel is increased, and the steering effect with respect to the steering operation is enhanced.

  The same applies to the case where the steering wheel is rotated in the θ2 direction, and the reverse direction, that is, the rotation guide 223 is rotated in the φ2 direction.

  4A to 4F show rotating guides 223a to 223f having various guide surfaces and various guide members 224a to 224f corresponding thereto.

  4 (a) and 4 (b) have a structure that is basically the same as that shown in FIG. 3. FIG. 4 (c) shows a rotation guide 223c whose cross section is flat and parallel, and the flatness of the rotation guide 223c. A guide member 224c having a guide surface that abuts against the parallel surface is shown.

  Subsequently, FIG. 4 (d) shows a case where a pin having a ring-shaped roller provided at the tip of the rotating guide 223d is projected to form a guide member, and the roller is rolled along the groove-shaped fixed guide surface. The rotary guide 223d is rotated.

  FIG. 4 (e) is configured as a rotation guide 223e and a guide member 224e configured to be opposite to those in FIG. 4 (a), and FIG. 4 (f) is a cross-sectional view of the rotation guide 223f. A fan-shaped guide groove is provided, and a guide roller 224f provided on the fixed side is engaged with the guide groove.

  As described above, various relationships between the rotation guide 223 and the guide member 224 can be selected. When the rotary guide 223 moves in the axial direction while being engaged with the guide member 224, it is common in that a twisting operation is added to perform a rotating action.

  5 (a) to 5 (c) show a fourth embodiment of the present invention. This example is basically similar to the structure shown in FIGS. 4A, 4B, and 4E, and a pin with a roller protrudes from the rotation guide 223, and this pin serves as a guide member 234. The guide groove is engaged.

  6 (a) and 6 (b) show a fifth embodiment of the present invention. This example has a structure common to that of FIG. 4 (f). In FIG. 4 (f), the engagement between the concave surface and the convex surface is changed to the engagement between the flat surfaces.

  Then, the tooth surface of the worm 241 corresponding to the guide member is wound around the circumferential surface, in other words, it is scraped off into a spirally twisted flat surface to form a guide surface, and the fixed-side guide surface is also planar. Is formed.

  FIG. 7 shows a sixth embodiment of the present invention. As in the second embodiment, this embodiment does not mechanically generate a twisting action, but rotates the gear 253a provided on the guide shaft by the gear 253a driven by the motor M on the fixed side. The guide shaft is rotated, and the worm 251 is rotated.

  FIG. 8 shows a seventh embodiment of the present invention in which the worm in the embodiment shown in FIG. 5 is replaced with a rack mechanism with a screw. That is, the steering force of the steering wheel is transmitted to the pinion 361, and the rack 261a meshing with the pinion 361 is moved in the left-right direction in the figure. The rack 261a meshes with a screw 261b provided on the screw shaft and is supported on the guide shaft, and is supported rotatably around the screw shaft.

  As a result, when a rotational force is applied to the screw shaft by the cooperation of the screw shaft 263 and the guide member 264, the screw 261b rotates to move the rack 261a in the axial direction.

The perspective view which shows the structure of the 1st Example of this invention. The perspective view which shows the structure of the 2nd Example of this invention. 3A is a perspective view showing a mechanism portion in the third embodiment of the present invention, FIG. 3B is a view showing the structure of the rotation guide 223, and FIG. 3C is a view showing the structure of the guide member 224 at different angles. FIG. FIGS. 4A to 4F are explanatory views showing rotation guides 223a to 223f having various guide surfaces and various guide members 224a to 224f corresponding thereto. FIG. 5A is a perspective view showing the fourth embodiment of the present invention, FIG. 5B is a perspective view showing the rotation guide 233a and its support member 233b, and FIG. 5C is a perspective view showing the guide member 234. Figure. FIG. 6A is a perspective view showing the rotation guide 243 in the fifth embodiment of the present invention, and FIG. 6B is an explanatory view showing an engagement state between the rotation guide 243 and the guide member 244. The perspective view which shows the 6th Example of this invention. The perspective view which shows the 7th Example of this invention. The perspective view which shows the steering mechanism of the conventional rack and pinion system. The perspective view which shows the steering mechanism of the conventional worm and worm wheel system.

Explanation of symbols

1 Wheel 101, 111, 121, 131, 151, 161 Support 2a, 201, 211, 261a Rack 202, 212 Rack shaft 2b, 221, 231, 241 Worm 3a, 301, 311, 361 Pinion 261b Screw 302 Pinion shaft 3b , 331, 351 Worm wheel 303, 313, 323 Steering shaft 304, 314 Spline joint 305, 315 Spline 306, 223, 233a, 243, 253a, 263 Rotating guide 307, 224, 234, 264 Guide member 316 Cylindrical rack 318a, 253b Gear 318b, 253c Motor 222, 232, 252, 262 Ball joint θ Steering direction φ Warm rotation direction

Claims (8)

A variable steering device for a vehicle that steers by changing the direction of a wheel by operating a tie rod, wherein the steering angle increases when the steering angle increases.
A rack rack provided with a helical rack and linked to the tie rod;
A helical pinion that engages with the helical rack and is supported so as to be axially movable, and is provided with a steering rotational force to move the rack shaft in the axial direction;
And a pinion guide mechanism for operating the helical pinion to move in the axial direction in accordance with the rotation of the helical pinion. The variable steering apparatus for a vehicle according to claim 1,
The pinion guide mechanism includes a follower that rotates following the rotation of the helical pinion;
And a cam member having a groove for restricting the operation of the follower. The variable steering apparatus for a vehicle according to claim 1,
The pinion guide mechanism includes a cylindrical rack provided on the helical pinion shaft,
A variable steering apparatus for a vehicle having a gear that engages with the cylindrical rack and drives the helical pinion in an axial direction in accordance with an operation force. A variable steering device for a vehicle that steers by changing the direction of a wheel by operating a tie rod, wherein the steering angle increases when the steering angle increases.
A worm shaft having a worm and linked to the tie rod for rotation about an axis;
A worm wheel that engages with the worm and is operated to rotate and axially move the worm shaft by being given a steering operation force;
A variable steering apparatus for a vehicle, comprising: a worm shaft guide mechanism that applies a rotational force to the worm shaft as the worm moves in the axial direction. The variable steering apparatus for a vehicle according to claim 4,
The worm shaft guide mechanism includes a follower provided so as to be wound around the worm shaft with a degree of twist that is gentler than the screw groove of the worm,
A variable steering device for a vehicle, comprising: a cam that restricts rotation of the follower. The variable steering apparatus for a vehicle according to claim 4,
The worm has a guide surface that is cut so that a circumferential surface thereof is wound around a rotation axis, and the variable steering device for a vehicle is configured such that rotation is regulated using the guide surface. The variable steering apparatus for a vehicle according to claim 4,
A long gear having an axially long groove provided on the worm shaft;
A short gear that meshes with this long gear,
A variable steering apparatus for a vehicle, comprising: a motor that drives the short gear. A variable steering device for a vehicle that steers by changing the direction of a wheel by operating a tie rod, wherein the steering angle increases when the steering angle increases.
A screw shaft having a helical screw and linked to the tie rod;
A rack is formed on at least a part of the outer periphery, and the movable body with a rack screwed to the screw shaft;
A guide member that supports the movable body with a rack so as not to rotate;
A follower provided on the screw shaft;
A variable steering apparatus for a vehicle, comprising: a guide mechanism that engages with the follower and restricts the rotation of the screw shaft as the follower moves in the axial direction.

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