KR20070103868A - Manual four wheel steering system - Google Patents

Abstract

A mechanical four-wheel steering system is provided to offer weighty control stability during turning, and to have fast response regarding turning operation and small rotation radius during U-turn by allowing a connecting shaft to be selectively engaged with a first rack gear of a rear wheel or a second rack gear of the rear wheel according to a steering angle. A mechanical four-wheel steering system comprises a steering shaft(50), a rack gear(60) of a front wheel(F), a connecting shaft(70), a first rack gear(80) of a rear wheel(R), a second rack gear(90) of the rear wheel and a control unit. The steering shaft includes a steering handle(53) mounted on an upper end, a bevel gear of the steering shaft in one side of a lower end and a pinion gear of the steering shaft in the other side of the lower end. The rack gear of the front wheel has both ends connected to a front wheel, and engaged with the pinion gear of the steering shaft. The connecting shaft includes the bevel gear of the steering shaft in an upper end, a first pinion gear of the connecting shaft in one side of a lower end and a second pinion gear of the connecting shaft in the side of the lower end. The first rack gear of the rear wheel has both ends connected to a rear wheel, and engaged with the first pinion gear of the connecting shaft. The second rack gear of the rear wheel has both ends connected to the rear wheel, and engaged with the second pinion gear of the connecting shaft. The control unit selectively controls engagement of the first pinion gear of the connecting shaft with the first rack gear of the rear wheel, and the engagement of the second pinion gear of the connecting shaft with the second rack gear of the rear wheel.

Description

Manual four wheel steering system

1 is a configuration diagram showing a mechanical four-wheel steering apparatus according to the present invention,

2 is a perspective view of a steering shaft of a mechanical four-wheel steering apparatus according to the present invention;

Figure 3 is a side view of the connecting shaft of the mechanical four-wheel steering apparatus according to the present invention,

4 is a perspective view showing a rear wheel connecting shaft and a control unit of the mechanical four-wheel steering apparatus according to the present invention;

5 is an enlarged configuration diagram of part C of FIG. 1;

FIG. 6 is an enlarged side view of part 1D of FIG.

7 is an operation state diagram schematically showing the operation of the mechanical four-wheel steering apparatus according to the present invention.

<Explanation of symbols on main parts of the drawings>

50: steering shaft 51: steering shaft bevel gear

52: steering shaft pinion gear 53: steering wheel

60: front wheel gear 70: connecting shaft

70a: front wheel connecting shaft 70b: rear wheel connecting shaft

71: First connecting shaft pinion gear 72: Second connecting shaft pinion gear

73: connecting shaft bevel gear 74: coupling pin

80: first rear wheel rack gear 81: first rear wheel knuckle arm

90: second rear wheel rack gear 91: second rear wheel knuckle arm

100: drive unit 101: rack

102: pinion 103: motor

B: Bearing F: Front Wheel

R: Rear wheel h1: Long hole

h2: Through hole S: Fixed protrusion

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical four wheel steering apparatus, and more particularly, to a four wheel steering apparatus capable of simultaneously steering the front and rear wheels of an automobile by a mechanical method.

In general, a steering system refers to a device for changing a driving direction of a vehicle as required by a driver by turning a steering wheel, which is an important mechanism together with a brake system for safety of driving a vehicle.

The steering apparatus according to the prior art is composed of three mechanisms: an operation mechanism, a steering gear apparatus, and a link mechanism.

The manipulation mechanism includes a steering wheel, a steering shaft, a column, and the like, and the driver directly manipulates the steering wheel to transmit the manipulation force to the steering gear device and the link mechanism.

The steering gear device is a part for reducing the rotation of the steering shaft to about 20: 1 to increase the operating force and at the same time changing the direction of movement of the operating mechanism to the link mechanism.

The steering gear device is largely classified into a ball nut type and a rack pinion type, and a rack pinion type is mainly used in a small vehicle.

The rack and pinion steering gear is provided with a pinion at the end of the steering shaft.

The link mechanism includes a rack that is engaged with the pinion so that the operation of the steering gear device can be transmitted to the front wheel, tie rods installed at both ends of the rack, and a knuckle arm coupled to the end of the tie rod. Arm) and the like.

The knuckle arm is installed to be connected to the steering knuckle which is the center of the wheel.

Therefore, when the driver manipulates the steering wheel and the operating force is transmitted to the steering gear device, the pinion of the steering gear gear is rotated and the rack of the link mechanism engaged with the steering gear moves laterally.

Thus, tie rods connected at both ends of the rack move the knuckle arm so that the direction of the wheel is diverted through the knuckle connected to the knuckle arm.

However, the steering apparatus according to the related art configured as described above has a poor steering response because the steering wheel controls only the front wheels of the vehicle, and thus the lane change is not effective. There is a problem.

The present invention has been made to solve the above problems of the prior art, and by adjusting the front and rear wheels of the vehicle at the same time by a mechanical simple method, by effectively using the grips of the tires of the front and rear wheels, the heavy adjustment stability when turning The purpose of the present invention is to provide a mechanical four-wheel steering device with rapid response to turning operation and a small turning radius at U turn.

Mechanical four-wheel steering device according to the present invention for solving the above problems is equipped with a steering wheel at the top and a steering shaft bevel gear is provided on one side, the steering shaft is provided with a steering shaft pinion gear on the other side; A front wheel rack gear connected to the front wheel at both ends thereof and engaged with the steering shaft pinion gear; A connecting shaft bevel gear meshed with the steering shaft bevel gear at an upper end thereof, a first connecting shaft pinion gear provided at one lower end thereof, and a connecting shaft having a second connecting shaft pinion gear provided at the other end thereof; A first rear wheel rack gear connected to the rear wheel at both ends thereof and engaged with the first connecting shaft pinion gear; A second rear wheel rack gear connected to the rear wheel at both ends thereof and engaged with the second connecting shaft pinion gear; And a control unit for selectively controlling the engagement of the first connecting shaft pinion gear and the first rear wheel rack gear and the engagement of the second connecting shaft gear and the second rear wheel rack gear.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram showing a mechanical four-wheel steering apparatus according to the present invention, Figure 2 is a perspective view of a steering shaft of the mechanical four-wheel steering apparatus according to the present invention, Figure 3 is a side view of a connecting shaft of the mechanical four-wheel steering apparatus according to the present invention. 4 is a perspective view illustrating a rear wheel connecting shaft and a control unit of the mechanical four-wheel steering apparatus according to the present invention, FIG. 5 is an enlarged configuration diagram of part C of FIG. 1, and FIG. 6 is an enlarged view of part D of FIG. 1. 7 is a side view, and FIG. 7 is an operation state diagram schematically showing the operation of the mechanical four-wheel steering apparatus according to the present invention.

The mechanical four-wheel steering apparatus according to the present invention is provided with a steering handle 53 at the top and a steering shaft bevel gear 51 at the lower side, and a steering shaft 50 provided with the steering shaft pinion gear 52 at the lower side. )and; A front wheel rack gear 60 having both ends connected to the front wheel F and engaged with the steering shaft pinion gear 52; A connecting shaft bevel gear 73 meshed with the steering shaft bevel gear 51 is provided at an upper end thereof, and a first connecting shaft pinion gear 71 is provided at one lower end side thereof, and a second connecting shaft pinion gear at the other end side thereof. A connecting shaft 70 provided with 72; A first rear wheel rack gear 80 having both ends connected to the rear wheel R and engaged with the first connecting shaft pinion gear 71; A second rear wheel rack gear 90 having both ends connected to the rear wheel R and engaged with the second connecting shaft pinion gear 72; A control unit for selectively controlling the engagement of the first connecting shaft pinion gear 71 and the first rear wheel rack gear 80 and the engagement of the second connecting shaft gear 72 and the second rear wheel rack gear 90; It is configured to include.

A steering handle 53 of the steering shaft 50 is provided in the vehicle compartment, and a steering shaft bevel gear 51 is provided at a lower end of the steering shaft 50, and above the steering shaft bevel gear 51. A steering shaft pinion gear 52 is provided.

A tie rod (not shown) is mounted at both ends of the front wheel rack gear 60, and a front wheel knuckle arm 61 for adjusting a turning angle of the front wheel F is connected to an end of the tie rod.

The connecting shaft 70 has a front wheel connecting shaft 70a having the connecting shaft bevel gear 73 at one end, and the first connecting shaft pinion gear 71 and the second connecting shaft pinion gear 72 at one end. The rear wheel connecting shaft 70b and the rear wheel connecting shaft 70b are rotated by being constrained by the rotation of the front wheel connecting shaft 70a and the rear wheel connecting shaft 70b is movable in the axial direction. Composed of a coupling unit for coupling the shaft (70a) and the rear wheel connecting shaft (70b).

The other end of the front wheel connecting shaft 70a is hollowed so that the rear wheel connecting shaft 70b can move in the axial direction along the inner surface of the front wheel connecting shaft 70a.

 A pair of first long hole h is formed at the other end of the front wheel connecting shaft 70a, and a second long hole h2 is formed at the other end of the rear wheel connecting shaft 70 that coincides with the first long hole h1. do.

Of course, in the present embodiment, the rear wheel connecting shaft (70b) is configured to move in the axial direction along the inner surface of the front wheel connecting shaft (70a), the rear wheel connecting shaft (70b) of the front wheel connecting shaft (70a) It may also be configured to move axially along the outer surface.

In the center of the rear wheel connecting shaft (70b) is provided with a fixing projection (S) so that the insertion groove is formed, the bearing for supporting the rear wheel connecting shaft (70b) rotatably in the insertion groove between the coupling projection (S) ( B) is installed.

The coupling unit includes a coupling pin 74 inserted into the long hole hole h1 of the front wheel connection shaft 70a and the through hole h2 of the rear wheel connection shaft 70b.

The first connecting shaft pinion gear 71 and the second connecting shaft pinion gear 72 are selectively engaged with the first connecting shaft pinion gear 71 and the second connecting shaft pinion gear 72, and the rear wheel F The diameter of the second connecting shaft pinion gear 72 is larger than the diameter of the first connecting shaft pinion gear 71 in order to change the rotational speed of.

A tie rod (not shown) is mounted at both ends of the first rear wheel rack gear 80, and a first rear wheel knuckle arm 81 for adjusting a turning angle of the rear wheel R is connected to an end of the tie rod. .

A tie rod (not shown) is mounted at both ends of the second rear wheel rack gear 90, and a second rear wheel knuckle arm 91 for adjusting a turning angle of the rear wheel R is connected to an end of the tie rod. do.

The second rear wheel gear 90 is provided to be spaced apart from the first rear wheel gear 80 by a predetermined interval, and the first rear wheel gear 8 and the second rear wheel gear 90 are separated from each other. The first connecting shaft pinion gear 71 and the second connecting shaft pinion gear 72 are disposed therebetween.

The control unit is connected to the sensing unit (not shown) for detecting the amount of rotation of the steering wheel 53, and the driving unit 100 is connected to the rear wheel connecting shaft 70b to move the rear wheel connecting shaft 70b in the axial direction. It is composed of

The detector is configured to send a signal when the steering wheel 53 is rotated more than a predetermined angle.

The drive unit 100 includes a rack 101 connected to a bearing B of the rear wheel connecting shaft 70b, a pinion 102 engaged with the rack 101, and a motor for rotating the pinion 102 ( 103).

In addition, the driving unit may be composed of a hydraulic cylinder, such as a piston connected to the bearing (B) of the rear wheel connecting shaft (70b).

Looking at the operation of the present invention configured as described above are as follows.

First, when driving in a straight line, as shown in (a) of FIG. 7, the first connecting shaft pinion gear 71 of the connecting shaft 70 and the first rear wheel steering shaft gear 80 are engaged with each other. do.

Next, when the driver turns the steering wheel 53 counterclockwise during the general turning (when the steering angle is less than a certain range), the steering shaft 50, the steering shaft pinion gear 52, and the steering shaft bevel gear 51 are the same. Is rotated in the direction.

Thus, as shown in Fig. 7 (b), the front wheel rack gear 60 is moved to the right by the steering shaft pinion gear 52 so that the front wheel F is turned counterclockwise.

Since the steering shaft bevel gear 51 and the connecting shaft bevel gear 73 are bitten, the connecting shaft bevel gear 73 rotates in the clockwise direction.

Since the first connecting shaft pinion gear 71 and the first rear wheel steering shaft gear 80 are bitten, the first rear wheel steering shaft gear 80 moves to the left, and the rear wheel R moves counterclockwise.

Next, when the driver further turns the steering wheel 53 counterclockwise to the U-turn (when the steering angle is greater than or equal to a predetermined range), the driver knows that the steering unit that has been checking the steering angle exceeds a predetermined range and sends a signal.

The motor 103 is operated by the signal of the sensing unit and the pinion 102 connected to the motor 103 rotates to move the rack 101.

The rack 101 is connected to the bearing B of the rear wheel connecting shaft 70b to move the rear wheel connecting shaft 70b in the axial direction.

Therefore, as shown in FIG. 7C, the rear wheel connecting shaft 70b is moved toward the front wheel F, so that the first connecting shaft pinion gear 71 and the first rear wheel steering shaft rack 80 are rotated. Is engaged, and the second connecting shaft pinion gear 72 and the second rear wheel steering shaft gear 90 are engaged with each other.

When the second connecting shaft pinion gear 72 and the second rear wheel steering shaft gear 90 are engaged with each other, the steering angle further rotated by the driver as shown in FIG. 7 (d) is the second rear wheel steering shaft gear. Since the 90 moves to the right, the rear wheel R is turned clockwise as opposed to the front wheel F. As shown in FIG.

Of course, since the diameter of the second connecting shaft pinion gear 72 is larger than the diameter of the first connecting shaft pinion gear 71, the clockwise direction of the rear wheel R, which is already turned counterclockwise, is quickly compensated. Is turning into.

Therefore, when a large steering angle, such as U turn, is large, the turning directions of the front wheels F and the rear wheels R are reversed, thereby reducing the turning radius of the vehicle.

When the driver starts to loosen the steering wheel 53, the steering is reversed.

In the mechanical four-wheel steering apparatus according to the present invention configured as described above, the front and rear wheels may be simultaneously steered by a connecting shaft connected to a steering shaft, and the connecting shaft is selectively connected to the first rear wheel steering shaft gear or the second according to the steering angle. By being engaged with the rear wheel steering shaft gear, the grip of the tires of the front wheel and the rear wheel can be effectively used to provide a heavy adjustment stability during the turning, and the quick response to the turning operation and the rotation radius at the U turn are small.

Claims (7)

A steering shaft mounted at an upper end of the steering wheel and having a steering shaft bevel gear at a lower side thereof, and having a steering shaft pinion gear at the lower end of the steering shaft; A front wheel rack gear connected to the front wheel at both ends thereof and engaged with the steering shaft pinion gear; A connecting shaft bevel gear meshed with the steering shaft bevel gear at an upper end thereof, a first connecting shaft pinion gear provided at one lower end thereof, and a connecting shaft having a second connecting shaft pinion gear provided at the other end thereof; A first rear wheel rack gear connected to the rear wheel at both ends thereof and engaged with the first connecting shaft pinion gear; A second rear wheel rack gear connected to the rear wheel at both ends thereof and engaged with the second connecting shaft pinion gear; And a control unit configured to selectively control the engagement of the first connecting shaft pinion gear and the first rear wheel rack gear and the engagement of the second connecting shaft gear and the second rear wheel rack gear. . The method according to claim 1, The connecting shaft and the front wheel connecting shaft having the connecting shaft bevel gear at one end; A rear wheel connecting shaft having one end of the first connecting shaft pinion gear and the second connecting shaft pinion gear; The rear wheel connecting shaft is constrained to rotate by the rotation of the front wheel connecting shaft, mechanical four-wheel steering device comprising a coupling unit for coupling the front wheel connecting shaft and the rear wheel connecting shaft so that the rear wheel connecting shaft is movable in the axial direction. . The method according to claim 2, A first long hole is formed at the other end of the front wheel connecting shaft, and a second long hole is formed at the other end of the rear wheel connecting shaft, the second long hole matching with the first long hole, and the other end of the front wheel connecting shaft and the other end of the rear wheel connecting shaft. One end of the other end of the connecting shaft and the other end of the rear wheel connecting shaft is formed to be inserted into the other side; The coupling unit is a mechanical four-wheel steering device, characterized in that consisting of the coupling pin is inserted into the first long hole of the front wheel connecting shaft and the second long hole of the rear wheel connecting shaft. The method according to claim 1, And a mechanical rear wheel steering apparatus disposed between the first rear wheel rack gear and the second rear wheel rack gear at a lower end of the connecting shaft. The method according to claim 1, Mechanical four-wheel steering device, characterized in that the diameter of the second connecting shaft pinion gear is larger than the diameter of the first connecting shaft pinion gear. The method according to claim 2, The control unit includes a sensing unit for sensing the amount of rotation of the steering wheel; And a driving unit connected to the rear wheel connecting shaft and configured to move the rear wheel connecting shaft in an axial direction. The method according to claim 6, The drive unit and the rack connected to the rear wheel connecting shaft; A pinion engaged with the rack; Mechanical four-wheel steering device, characterized in that consisting of a motor for rotating the pinion.

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