JPH0679908B2 - Rear wheel steering mechanism - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rear wheel steering mechanism of a vehicle.

(Prior Art) In the Japanese Patent Application No. 61-79567 (see Japanese Patent Application Laid-Open No. 62-238170), the present applicant has proposed an input shaft in the front-rear direction in which the rotation extracted from the front wheel steering mechanism is input, and a parallel input shaft. A main shaft for transmitting rotation, a diametrical arm provided at a rear end of the main shaft, a left and right movable output member arranged behind the diametrical arm, and a vertical direction provided on the output member. And a slide member which is interposed between the guide and the arm and which is slidable in the vertical direction with respect to the guide and is slidable in the diameter direction of the main shaft with respect to the arm. A rear wheel steering mechanism for a vehicle has been proposed in which the rotation of the main shaft is converted into the left-right movement of the output member by moving the drive device in the vertical direction to steer the rear wheels.

According to this, since the slide member is only moved up and down without moving the output member itself up and down, a small driving force is required to adjust the steering angle of the rear wheels.

(Problems to be Solved by the Invention) In such a rear-wheel steering mechanism, if the rotation extracted from the front-wheel steering mechanism is directly input to the main shaft, the influence of backlash and torsional rigidity in the transmission path of the rotation from the front-wheel steering mechanism is affected. Is directly transmitted to the spindle, so it is necessary to greatly reduce the rotation speed before the spindle. Therefore, it suffices to arrange the rotary input shaft parallel to the main shaft and provide a speed reduction mechanism between the two, but in order to eliminate the effects of backlash and torsional rigidity on the main shaft and ensure the rear wheel steering mechanism, a large reduction ratio is required. Therefore, when the external gears are meshed with each other, the distance between the shafts is reduced and the reduction gear mechanism is increased in size, so that the rear wheel steering mechanism cannot be made compact.

Then, in order to accurately transmit the rotation from the front wheel steering mechanism to the main shaft through the reduction gear train from the input shaft, it is necessary to remove the play between the reduction gears and adjust the mesh.

Therefore, an object of the present invention is to greatly reduce the rotation between the rotary input shaft and the main shaft to remove the influence of backlash and torsional rigidity from the front wheel steering mechanism, to ensure the rear wheel steering mechanism, and to secure the shaft between the input shaft and the main shaft. This contributes to downsizing of the reduction mechanism by reducing the distance between them, realizing a compact mechanism as a whole, and eliminating rattling between the input shaft and the main shaft so that rotation can be accurately transmitted to the main shaft. A rear wheel steering mechanism for a vehicle is provided.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a pinion (12) and a main shaft (21) provided at a rear end of an input shaft (11) in a rear wheel steering mechanism of the type described above. A cylindrical member (15) that rotatably supports the input shaft (11) in the front part of the gear box (81) by meshing with the internal gear (22) provided on the cylindrical member. Screw holes (83) and (83) that open to the left and right of (15) are formed, and a pair of left and right adjustment screws (17) and (17) that rotate by contacting the tubular member (15) are provided in the screw holes (83). ), (83).

(Operation) Rotation entering the input shaft (11) is greatly reduced by the pair of pinions (12) and internal gear (22) and transmitted to the main shaft (21). The influence of backlash and torsional rigidity in the rotation transmission path from the steering mechanism is greatly reduced to 1 / k on the main shaft (21). Moreover, since the gear on the main shaft (21) side is the internal gear (22),
The distance between the input shaft (11) and the main shaft (21) is reduced, and the reduction mechanism can be downsized.

When the pair of left and right adjusting screws (17) and (17) are adjusted, the tubular member (15) is rotationally adjusted, and the tubular member (15) eccentrically supports the input shaft (11). The play between the pinion (12) and the internal gear (22) can be removed to adjust the meshing.

(Examples) Examples will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view of a front and rear wheel steering device. The front wheel steering mechanism includes a steering wheel (1), a rotation input pinion shaft (2), a rack shaft (3), left and right tie rods (4) and a knuckle arm (5). ) Etc., (6) is a front wheel steering gear box, (7) is left and right front wheels, and the gear box (6) has a rotary take-out pinion shaft (8) meshing with the rack shaft (5).
Is projected and installed in the rear. A linkage shaft (9) is connected to the rotary take-out pinion shaft (8), and a rotation input shaft (11) of a rear wheel steering mechanism is connected to the linkage shaft (9).

The main part of the rear wheel steering mechanism is as shown in FIG. 2, and comprises a rotary input shaft (11), a main shaft (21), an output member (41), a slide member (51) and a drive device (71). Details are shown in FIGS. 4 to 7, and in FIG. 1, (81) is a rear wheel steering gear box, (91) is an ECU as a control device, (92) is a vehicle speed sensor, and (94) is a tie rod. , (95) is a knuckle arm, and (97) is a rear wheel.

As shown in the figure, a pinion (12) is formed at the rear end of the rotary input shaft (11) facing the front-rear direction, and the main shaft (21) is arranged in parallel directly above the input shaft (11). ) A fan-shaped internal gear (22) that meshes with the pinion (12) from below is vertically provided integrally with the rear portion of the internal gear (22), and a diametrical arm (21) of the main shaft (21) is provided on the rear surface of the internal gear (22). twenty three)
Are integrally formed. The internal gear (22) and the arm (23) are maintained in the vertical state at the steering neutral position of the rear wheel (87).

The rotary input shaft (11) is rotatably incorporated into the tubular member (15) via the front and rear ball bearings (13) and needle bearings (14), and the tubular member (15) has an input shaft (as shown in FIG. 5). 11) is eccentrically supported. The tubular member (15) is rotatably incorporated into the front portion (82) of the rear wheel steering gear box (81), and a pair of left and right concave stepped portions (1
6) and (16) are formed. A pair of left and right screw holes (83) and (83) are formed on the left and right of the gear box front part (82) and open to the side of the concave step parts (16) and (16).
A pair of left and right adjusting screws (17) and (17) whose tips are respectively in contact with the concave stepped portions (16) and (16) are screwed into the insides of (3) and (83).

In addition, the main shaft (21) has front and rear ball bearings (24), (2
5) It is rotatably installed in the front part (82) of the gear box, and the collar (26) and the flange (27) at the rear end are installed between the outer rings of both bearings (24) and (25). . Here, the inner ring of the front bearing (24) and the main shaft (21) are fitted so as to be movable in the axial direction, and the outer ring of this bearing (24) and the outer ring of the rear bearing (25) and the front part of the gear box ( Both of them are fitted so that they can move in the axial direction. A screw hole (84) opening forward of the main shaft (21) is concentrically formed on the front surface of the gear box front part (82), and an adjusting screw (28) is screwed into the screw hole (84). A cap (29) is provided between the adjusting screw (28) and the outer ring of the front bearing (24). Further, a coil spring (32) is contracted between the retainer (31) fixed to the front end of the main shaft (21) and the inner ring of the front bearing (24), and between the collar (26) and the flange (27). The disc spring (33) is also compacted.

An output member (41) is arranged behind the arm (23) so as to be separated therefrom. The output member (41) is a shaft-like object which is horizontally arranged so as to be oriented in the left-right direction, and the output member (41) is arranged in the vertical direction at the center thereof. The guide (42) is fixed by bolts (43) and (43). The output member (41) is movably incorporated in the left and right directions of the gear box rear part (85) via the metal bearings (44) and (44), and is a slide member between the guide (42) and the arm (23). (51) is installed.

The slide member (51) is tapered from the rear with respect to the arm (23) and is slidable in the diametrical direction of the main shaft (21), and the guide (42) is tapered from the front. A second slide piece (53) fitted and slidable in the vertical direction, and a center piece (54) interposed between the slide pieces (52) and (53) and rotatably fitted to each other.
And a horizontal support shaft (61) for movably supporting the center piece (54).

Needle bearings (55) and (55) are provided on the left and right of the tapered fitting portion between the first slide piece (52) and the arm (23), and the second slide piece (53) and the guide (42) are connected to each other. Needle bearings (56) on the left and right of the taper fitting,
(56) is interposed. Further, a ball bearing (57) is interposed in the fitting portion between the first slide piece (52) and the front portion of the center piece (54), and the fitting between the second slide piece (53) and the rear portion of the center piece (54). A ball bearing (58) is also installed at the joint. Further, the center piece (54) is mounted on the support shaft (61) via the slide bearing (59).

The support shaft (61) is divided into left and right cylinder shafts (62) and rod shafts (64).
The rod shaft (64) is slidably assembled in the cylinder shaft (62), and the coil spring (66) is contracted between the two, and the outer ends of the cylinder shaft (62) and the bar shaft (64) are Are engagement protrusions (63), (65) that are wide in the front-rear direction and have an arc-shaped front section.
Is formed in.

A drive device (71) for vertically moving the support shaft (61).
Is provided.

The drive device (71) includes a motor (72) with an encoder that monitors the number of rotations and a rotation angle, four gears (73), (74), (74), and (75) that are arranged side by side in the left-right direction. It is composed of a pair of vertical feed screws (76) and (76) and a pair of left and right nut members (77) and (77). The motor (72) is fixedly installed on one side of the rear part (85) of the gear box and has a drive gear (73) at the upper end thereof, and a pair of left and right feed screws (76), (7
6) is vertically rotatably installed in the rear part (85) of the gear box and is located on both sides of the slide member (51).
The driven gear (74) is fixed to both upper ends of 6). An intermediate gear (75) is interposed between the left and right driven gears (74), (74), and the above four gears (73), (74), (74), (7)
5) projects above the rear portion (85) of the gear box and is covered by the gear cover (86). Also the feed screw (76),
The inner ends of the nut members (77) and (77) that are respectively screwed into the (76) are formed in engaging recesses (78) and (78) having a circular arc-shaped cross section. ), (78), engaging projections (63), (65) at the end of the support shaft (61) are engaged, respectively.

Thus, between the left and right nut members (77) and (77), the support shaft (6
1) is erected.

The basic principle of the main part of the rear wheel steering mechanism is as shown in FIG. 3, and the slide member (51) is represented as one sphere.

Here, the rotation speed and rotation angle information of the motor with encoder (72) are input to the ECU (91) and compared with the vehicle speed information from the vehicle speed sensor (92) to determine the optimum front-rear wheel steering angle ratio according to the vehicle speed. Is determined and the operation of the motor (72) is always confirmed.

Next, the operation will be described, but since the operation of the front wheel steering mechanism is known, only the operation of the main part of the rear wheel steering mechanism will be described.

First, when the rotation extracted from the front wheel steering mechanism is input to the input shaft (11), the pinion (22) and the internal gear (22)
The rotation reduced by the reduction ratio k is transmitted to the main shaft (21).

On the other hand, the rotation of the motor (72) according to the vehicle speed information causes the gear (7
3), (74), (75), (74), left and right lead screw (7
6), (76), the lead screw (76), (76)
The left and right nut members (77), (77) move up and down by the rotation of
The center piece (54) moves up and down in parallel through the support shaft (61) installed between the first slide piece (52).
Slides along the arm (23) in the diameter direction of the main shaft (21), and the second slide piece (53) slides vertically along the guide (42).

Since the arm (23) rotates integrally with the main shaft (21), the first slide piece (52) fitted to the arm (23)
Rotates with respect to the main shaft (21), and this crank rotation is converted into lateral movement of the center piece (54). The second slide piece (53) horizontally moves integrally with the center piece (54), and the output member (41) integrated with the guide (42) fitted to the second slide piece (53) also horizontally moves. .

Thus, the front wheels (7), (7) and the rear wheels (97), (9
The steering angle ratio in 7) is adjusted to the optimum value according to the vehicle speed.

By the way, a motor (7) provided with a drive gear (73 ') meshing with the other driven gear (74) as shown in phantom in FIG.
2 ') may be added.

In the above, the internal gear (22) that meshes with the pinion (12) of the input shaft (11) from below is provided on the main shaft (21) to greatly reduce the speed and transmit the rotation. The influence of backlash and torsional rigidity in the rotation transmission path can be greatly reduced to 1 / k before the main shaft (21) and removed. Also, the adoption of the internal gear (22) reduces the axial distance between the input shaft (11) and the main shaft (21), so the reduction gear mechanism can be downsized and the rear wheel steering mechanism can be made compact as a whole. Will also contribute.

Then, a pair of left and right adjusting screws (17), (1
7) If one is screwed in, the adjusting screw (17) pushes in one concave step (16) and the tubular member (15) rotates, so that the tubular member (15) is supported eccentrically. Input shaft (11)
The play between the pinion (12) and the internal gear (22) can be removed, and the meshing can be adjusted.

As described above, since the rotation from the front wheel steering mechanism can be greatly reduced and the backlash can be removed and transmitted to the main shaft (21) with high accuracy, the rear wheel steering mechanism can be guaranteed.

Incidentally, if a spring member is interposed between the tubular member (15) and the front portion (81) of the gear box to preload the tubular member (15), the meshing adjustment can be automatically performed.

(Effect of the Invention) As described above, according to the present invention, a large reduction ratio is obtained between the rotary input shaft and the main shaft to eliminate the influence of backlash and torsional rigidity from the front wheel steering mechanism, and the reduction mechanism is made compact. Therefore, it is possible to achieve the downsizing of the entire mechanism while ensuring the rear wheel steering function, and it is also possible to remove the play between the input shaft and the main shaft, so that the rotation can be accurately transmitted to the main shaft.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a front and rear wheel steering device, FIG. 2 is a perspective view of a rear wheel steering mechanism, FIG. 3 is a basic principle diagram thereof, and FIG. 4 is a sectional view taken along line IV-IV of FIG. 5 is a sectional view taken along line VV of FIG. 4, and FIGS. 6 and 7 are taken along line VI-VI and VII-VII of FIG.
It is each sectional drawing of a line. In the drawings, (8) is a rotary extraction pinion shaft, (9) is a linkage shaft, (11) is an input shaft, (12) is a pinion,
(13), (14) are bearings, (15) are tubular members, (16)
Is a concave step, (17) is an adjusting screw, (21) is a main shaft, (22) is an internal gear, (23) is an arm, (41) is an output member, (42) is a guide, and (51) is a slide. Material, (52),
(53) is a slide piece, (54) is a center piece,
(61) is a spindle, (71) is a drive unit, (72) is a motor,
(72), (74) and (75) are gears, (76) is a lead screw,
(77) is a nut member, (81) is a gear box, (83) is a screw hole, (86) is a gear cover, (91) is a control device, (9)
2) is a vehicle speed sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Abe 1-4-1 Chuo Wako, Saitama Prefecture Honda R & D Co., Ltd. (72) Inventor Yasuharu Oyama 1-4-1 Chuo Wako, Saitama (56) References JP 62-238170 (JP, A) JP 61-9378 (JP, A)

Claims (1)

[Claims] 1. A front-rear input shaft for inputting a rotation extracted from a front wheel steering mechanism, a main shaft arranged in parallel with the input shaft for transmitting rotation, and a diametrical direction provided at a rear end of the main shaft. An arm, an output member that is spaced apart from the rear of the arm and is movable in the left-right direction, a vertical guide provided on the output member, and an intervening member between the guide and the arm. A sliding member that is slidable in the vertical direction and slidable in the diameter direction of the spindle with respect to the arm is built in the gear box, and the spindle is rotated by moving the sliding member in the vertical direction by a drive device. In a rear wheel steering mechanism of a vehicle for converting rearward movement of the output member to steer the rear wheels, wherein a pinion is provided at a rear end of the input shaft while the main shaft meshes with the pinion. Internal gear installed Further, a cylindrical member that eccentrically supports the input shaft and is rotatably supported is rotatably assembled in the front portion of the gear box, and screw holes that open laterally of the cylindrical member are provided on the left and right of the front portion of the gear box. And a pair of left and right adjusting screws for abutting and rotating the tubular member are screwed into the screw hole.