JPS6341347B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a joint in which the rotation angle of the output shaft is varied while maintaining a constant functional relationship with respect to the rotation angle of the input shaft, and a method for steering the rear wheels together with the front wheels using the joint. The present invention relates to a steering device for a vehicle.

The present applicant has provided a steering system for a vehicle in which front wheels and rear wheels can be simultaneously steered by first steering a steering wheel.

Incidentally, it is desirable for driving operation that the rear wheels be steered while maintaining a constant functional relationship in accordance with the steered angle of the front wheels.

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide a joint that changes the rotation angle of an output shaft with respect to the rotation angle of an input shaft while maintaining a constant functional relationship.

An embodiment of the joint according to the present invention will be described below based on FIGS. 5a, b, and c.

In FIG. 5a, 12 is an input shaft, and an output shaft 14 is connected to the input shaft 12 so as to be vertically swingable.

A yoke member 15 is fitted around the outer periphery of the output shaft 14 so that the output shaft 14 can rotate freely relative to the yoke member 15, and the tip of the yoke member 15 is connected to a pivot shaft 16a relative to a fixed member (not shown) It is connected to a swinging member 16 that is pivotally supported around the periphery so as to be able to swing back and forth.

Based on the above configuration, the operation will be explained in detail as follows.
In a state where the output shaft 14 and the input shaft 12 do not form an angle, the output shaft 14 internally rotates idly with respect to the yoke member 15.

The yoke member 15 is tilted with respect to the input shaft 12 by swinging the swinging member 16 around the pivot shaft 16a,
When an angle is given to the output shaft 14 and input shaft 12, the output shaft 14 cannot rotate around the axis, and the yoke member 15 moves in the left-right direction to allow rotation of the input shaft 12, and as described later, the rear wheels are rotated. Be steered.

If the output shaft 14 is tilted downward by an angle α as shown in FIG. Ru. At this time, the relationship between the rotation angle of the output shaft 14 around the Y'-Y' axis with respect to the inclination angle α and the rotation angle θ of the input shaft 12 is expressed by the following equation.

tan=sin α·tan θ Therefore, the rotation angle of the output shaft 14 can be changed with respect to the rotation angle θ of the input shaft 12 while maintaining a constant functional relationship.

That is, by increasing the inclination angle α of the input/output shaft, the output rotation angle can be increased even for the same input rotation angle θ, and the amount of rear wheel turning can be increased as described later.

By the way, if such a joint is applied to a steering system of a vehicle that steers the front and rear wheels, and the inclination angle α of the output shaft 14 is changed according to the vehicle speed, the steering ratio of the front and rear wheels can be adjusted to the vehicle speed. The optimal one can be set according to the requirements.

Therefore, a second object of the present invention is to provide a vehicle in which the driveability of the vehicle can be further improved by using the coupling and inclining the output shaft thereof by a predetermined angle depending on the vehicle speed. to provide steering equipment.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the basic structure of a four-wheel vehicle equipped with a steering device according to the present invention, FIG. 2 is a perspective view of a variable ratio mechanism of the steering device, and FIG. 3 is a perspective view of the variable ratio mechanism of the steering device. -3 line sectional view and FIG. 4 are perspective views of the same mechanism with the housing removed.

Reference numeral 1 in FIG. 1 denotes a steering wheel operated by the driver, and its steering shaft 2 is connected to a direction change means built into a gearbox 3, and the steering wheel 1 is rotated by, for example, a rack-and-pinion system. The direction changing means converts the movement of the left and right front wheel steering tie rods 5, 5 in the width direction of the vehicle body via the connecting rod 4. The outer ends of both tie rods 5, 5 are connected to knuckle arms 7, 7 which support the front wheels 6, 6 and are rotatable in the left and right directions, and the front wheels 6, 6 are steered by the above movement of the tie rods 5, 5. ring 1
is steered in the steering direction.

The configuration of the front wheel steering means described above is the same as the known one, and by attaching a power steering device to the gearbox 3, the steering operation of the steered wheels 1 is assisted by the power steering device.

A connecting shaft 8 is connected to the internal mechanism of the gearbox 3 via an operating force transmission means suitable for the mechanism such as a rack and pinion, a bevel gear, a worm gear, etc., and an operating shaft 9 extending in the longitudinal direction of the vehicle body is connected to the connecting shaft 8. The front ends of the two are connected by a universal joint 10. A universal joint 1 is attached to the rear end of this operating shaft 9.
The front end of an input shaft 12 is connected to the input shaft 12 through a universal joint 13, and the front end of an output shaft 14 is connected to the rear end of the input shaft 12 through a universal joint 13.

As shown in FIGS. 3 and 4, a yoke member 15 is fitted around the outer periphery of the output shaft 14 so that the output shaft 14 can rotate freely relative to the yoke member 15. The front end of the yoke member 15 has a rectangular shape. Swinging member 1 which is a frame body
The tie rods 1 for steering the rear wheels are connected to the yoke member 15 so as to be swingable only in the left and right directions.
The inner ends of 7 and 17 are connected. The swing member 16 is swingably housed in a housing 19 via a pivot shaft 18 protruding from both side walls of the swing member 16. Then, the housing 1 of one rotation shaft 18
As shown in FIGS. 2 and 4, a worm gear 20 is fitted to the end portion of the worm gear 9 projecting outwardly so as to rotate together with the worm gear 20.

On the other hand, a motor 21 is fixed to the side wall of the housing 19, as shown in FIG. .

By the way, a computer 24 is installed in the vehicle, and the computer 24 receives signals from a vehicle speed sensor 25 that detects the vehicle speed and a position sensor 26 that detects the rotational position of the output shaft 14, and sends an appropriate control signal to the motor 21. Send it to control its rotation.

The outer ends of the rear wheel steering tie rods 17, 17 are connected to knuckle arms 28, 28 that support rear wheels 27, 27, as shown in FIG. 1, and each knuckle arm 28 has its upper end connected to the vehicle body. The shock absorber 29 and its inner end are suspended by lower arms 30, 30 which are vertically swingably connected to the vehicle body.

Next, the operation of the present steering system will be explained based on FIGS. 3, 4, and 5 a, b, and c. Note that FIGS. 5a, b, and c are perspective views showing the operating principle of the present steering system, and in order to clarify the operation of the mechanism shown in FIG. 4, the opposing connection points and connection members are omitted. However, the operation of each member is the same.

The swinging member 16 is connected to a housing 19 that serves as a fixed member.
The yoke member 15 swings around the Z-Z axis that coincides with the rotation axis 18 of the yoke member 15, and the yoke member 15 is swingably connected to the swing member 16 only in the left and right directions, and is rotatably fitted into the yoke member 15. The output shaft 14 can swing only in a direction perpendicular to the pivot axis 13b with respect to the input shaft 12.
Here, the universal joint 13 between the input and output shafts includes an input side member 13a, an output side member 13c, and a pivot 13b between them.
Consists of.

The left and right positions of the rear wheel steering tie rods 17, 17 are determined by the amount of rotation of the yoke member 15 around the Y-Y axis, but the output shaft 14 is positioned concentrically with the input shaft 12 as shown in FIG. Then, that is, both shafts 12,1
4 coincides with the X-X axis, even if the input shaft 12 rotates, the yoke member 15 does not rotate around the Y-Y axis. Therefore, in this case, the tie rods 17, 17 remain stationary, and the front wheels 6, Only the rear wheels 27 and 2 are steered.
7 is not steered at all like conventional cars.

By the way, when the vehicle is traveling at a low speed where the vehicle speed is less than a set value, the computer 24 receives signals from the vehicle speed sensor 25 and the position sensor 26 and makes a judgment, and controls the rotation of the motor 21 according to the vehicle speed at that time. By controlling the rotation of the motor 21, the worm 23 provided on the drive shaft 22 of the motor 21 rotates the worm gear 20 meshing with the worm 23. For example, as shown in FIG. 5b, the angle .alpha. is tilted downward. As a result, the rotation of the input shaft 12 is converted into the rotation of the yoke member 15 about the Y'-Y' axis in FIG. 5b.

In other words, the locus drawn by the yoke member 15 is a circular arc surface inclined at an inclination angle α around the Y'-Y' axis, since the yoke member 15 can only swing around the Y'-Y' axis with respect to the swinging member 16. Since the output shaft 14 can swing around the pivot 13b with respect to the input shaft 12,
It becomes a plane around the pivot 13b, and when the input shaft 12 is rotated at a rotation angle θ, it is on a straight line obtained by intersecting the plane around the axis where the pivot 13b is tilted around the X-X axis at an angle θ and the circular arc surface. An output shaft 14 and a yoke member 15 are arranged. Inclination angle α at this time
and the yoke member 15 with respect to the rotation angle θ of the input shaft 12.
The function of the rotation angle around the Y'-Y' axis is expressed by the following equation.

tan=sinα·tanθ From the above equation, by changing the inclination angle α, the relationship between the rotation angle and θ can be made variable.

That is, by increasing the inclination angle α of the input/output shaft, the output rotation angle can be increased even for the same input rotation angle θ, and the amount of rear wheel steering can be increased.

Therefore, when the yoke member 15 rotates around the Y'-Y' axis, the rear wheel steering tie rods 17, 17
It moves left and right, thereby allowing the rear wheels 27, 27 to be steered in the opposite direction to the front wheels 6, 6, and also allowing the front and rear wheel steering ratios to be changed continuously in accordance with the vehicle speed.

Next, when the vehicle speed increases beyond the set value, the computer 24 causes the motor 21 to rotate in reverse, so that the output shaft 14 and yoke member 15 move upward by an angle α relative to the input shaft 12, as shown in FIG. 5c. This causes the yoke member 15 to rotate about the Y''-Y'' axis. Then, yoke member 1
a tie rod 17 having an inner end connected to the tie rod 5;
17 moves left and right, which causes the rear wheels 27, 27
can be steered in the same direction as the front wheels 6, 6.

As described above, since the rear wheels are steered in the opposite direction to the front wheels when driving at low speeds, the turning radius of the vehicle can be significantly reduced, thereby improving the maneuverability of the steered wheels. .

In addition, when driving at high speeds, the rear wheels are steered in the same direction as the front wheels, so even immediately after the start of steering, the rear wheels generate cornering force at the same time as the front wheels, and the lateral acceleration of the vehicle reaches the intended value in a short time. It is possible to improve steering stability by improving steering response.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view showing the general basic structure of a four-wheeled vehicle equipped with a steering device according to the present invention, and FIG. 2 is a perspective view showing a variable ratio of the steering device. A perspective view of the mechanism, Figure 3 is a sectional view taken along the line 3-3 in Figure 2, Figure 4 is a perspective view of the mechanism with the housing removed, and Figures 5a, b, and c show the operating principle of the steering system. FIG. In the drawing, 1 is a steering wheel, 5 is a front wheel steering tie rod, 6 is a front wheel, 9 is an operating shaft, 12 is an input shaft, and 14
is an output shaft, 15 is a yoke member, 16 is a swinging member,
17 is a rear wheel steering tie rod, 20 is a worm gear, 21 is a motor, 23 is a worm, 24 is a computer, 25 is a vehicle speed sensor, and 26 is a position sensor.

Claims (1)

[Scope of Claims] 1. Two rotating shafts connected to each other so as to be able to swing up and down, a yoke member that is rotatably fitted to one of the two rotating shafts, and a yoke member that is pivotally supported to be able to swing left and right. A joint comprising: a swinging member; and a fixed member supporting the swinging member so as to be swingable back and forth. 2. In a vehicle steering system in which the front wheels and the rear wheels are steered by the steering operation of the steering wheels, an output shaft is connected to the rear end of an input shaft that rotates in conjunction with the steering wheels so as to be able to swing vertically, The output shaft is rotatably fitted into a yoke member to which left and right rear wheel steering tie rods are connected, the yoke member is pivotally supported on a swinging member so as to be swingable left and right, and the swinging member is placed on the vehicle body side. The motor is supported in a housing fixed to the vehicle so as to be able to swing back and forth through a rotating shaft, and between the rotating shaft and the drive shaft of a motor that is fixed to the vehicle body and whose rotation is controlled according to the vehicle speed. A vehicular steering device characterized by having a worm gear mechanism interposed therein.