JPS5926364A - Steering apparatus for car - Google Patents

Abstract

PURPOSE:To improve operation performance by freely fitting a joint member with which a rear-wheel tie-rod is connected onto an oscillating member driven by a motor and allowing the steering direction of rear wheels to be varied according to car speed, in an apparatus for steering rear wheels, interlocked with the steering of front wheels. CONSTITUTION:At the same time when front wheels are steered by the operation of a steering wheel, rear wheels 22 are steered through an operating shaft 9. In such a sterring apparatus, an oscillating shaft 14 is connected at the rear edge of the operating shaft 9 through a universal joint 11, input shaft 12, and a universal joint 15. A joint member 16 with which the inner edge parts of a rear-wheel steering tie-rod 25 are connected on both edge parts is freely fitted in the intermediate part of the oscillating shaft 14, and the center part of an arm member 17 which exteends in the direction of car width is fixed onto the member 16. The right edge of the arm member 17 is conected to the chassis side through a link 18 and a bracket 19, and the left edge is connected to the chassis side through links 20 and 21 and a bracket 22. The worm gear 32a on an output shaft 32 for a motor 31 is engaged with a sector gear 24 fitted onto the pivotal shaft 23 of the link member 21.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering system for a vehicle, particularly a four-wheeled vehicle, and more specifically, a steering system for a four-wheeled vehicle that controls the steering angle ratio between front wheels and rear wheels according to vehicle speed. The present invention relates to a vehicle steering system which facilitates steering and greatly reduces the minimum turning radius.

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

The present invention further improves such a steering device to control the steering angle ratio between the front wheels and the rear wheels according to the vehicle speed. The object of the present invention is to steer the rear wheels in the same direction as the front wheels when the vehicle is running at high speed, and to steer the rear wheels in the opposite direction to the front wheels when the vehicle is running at low speed. Thus, □ To provide a steering system for a vehicle that improves the controllability of the steering wheels during high-speed running and the steering wheel operability during low-speed running.

To achieve such an object, the present invention connects a swinging shaft with a universal joint to the rear end of an input shaft that rotates in conjunction with a steering wheel, and A joint member formed by connecting a rear wheel steering tie rod to the right side of the shaft is fitted in a relatively rotatable manner, and an arm member whose length direction is in the width direction of the vehicle body is fixed to the joint member. Both ends of the arm member are connected to the vehicle body via link portions, and a motor whose rotation is fully controlled in accordance with the vehicle speed is disposed at one end of the arm member.

A device is constructed by interposing a worm gear mechanism between the output shaft of the motor and the link assembly of the arm member.Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a four-wheeled vehicle equipped with a steering system according to the present invention, FIG. 2 is an enlarged perspective view of a first fixed part, and FIG. tb+, (C) is a schematic diagram showing the operating principle of the present steering system.

In FIG. 1, reference numeral 1 denotes a steering wheel operated by the driver, and its two steering shafts, 1. The steering rotation of the steered wheels 1 is controlled by the direction changing means using, for example, a rack-at-pinion system, via the connecting member 4, and the left and right front wheel steering tie rods 5, 5.
is converted into a movement in the width direction of the vehicle body. The outer ends of both tie rods 5.5 are connected to a knuckle arm 7.7 that supports a front wheel 6.6 and is rotatable in the left-right direction. The vehicle is steered in the first steering direction.

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

A connecting shaft 8 is connected to the internal mechanism of the gearbox 6 through a working force transmitting means suitable for the mechanism, such as a rack and pinion, a beher gear, and a four-wheel drive mechanism. The front end of the operating shaft 9 extending thereto is connected by a universal joint 10. The front end of an input shaft 12 is connected to the rear end of the operating shaft 9 by a universal joint 11, and the input shaft 12 is rotatably supported by a bearing bracket 13 attached to the vehicle body. Furthermore, as shown in detail in FIG. 2, the front end of a swing shaft 14 is connected to the rear end of the human power shaft 12 with a universal joint 15, and the swing shaft 1
As shown in the figure, a joint member 16 is interposed between 4 and 4 so as to be relatively rotatable. It is fixed.

Each end of the arm member 17 is connected to the vehicle body via a link part 18 and a vine bracket 19, and the left end is connected to the vehicle body via a link assembly 20, 21 and a link bracket 22. stop.

The sector gear 24 is attached to the pivot shaft 2 of the link assembly 21.
is fitted, and the hitta gear 24 is configured to rotate together with the link part 21.

Furthermore, on the left and right sides of the above-mentioned joint part [416], the inner ends of the tie rods 25 and 25 for steering the rear wheels are connected to the hole joints 26,
26, and the outer ends of both tie rods 25.25 are connected to a knuckle arm 28.28 which supports a rear wheel 27.27, as shown in FIG. Each knuckle arm 28 is suspended by a shock absorber 29 whose upper end is connected to the vehicle body and a lower arm 30, 30 whose inner end is connected to the vehicle body so as to be vertically swingable.

On the other hand, a motor 61 is disposed on the vehicle body side of the left end outer extension of the arm member 17, and an output shaft 62 of the motor 31 constitutes a worm gear 32a (-1) The worm gear 32a and the sector gear 24 are in mesh with each other as shown in the figure. are doing.

By the way, a computer 66 is installed in the vehicle, and the computer 66 has a vehicle speed sensor 64 that detects the vehicle speed and a position sensor 65 that detects the rotation (r>position) of the link part @21.
In response to the signal from the motor 31, an appropriate control signal corresponding to the medium speed is sent to the motor 31 to control its rotation.

If the pivot point p of the joint member 16 coincides with the center oK of the input shaft 12 as schematically shown in FIG. Therefore, at this time, the joint part 16 does not swing from side to side.
The tie rods 25.25 whose inner ends are connected to the joint assembly 16 are immovable, and at this time only the front wheels 6.6 are steered, and the rear wheels 27.27 are not steered at all as in conventional vehicles. .

By the way, when the vehicle speed is running at a low speed below a set value, the computer 36 receives a signal from the vehicle speed sensor 64 to determine, and controls the rotation of the motor 61 according to the vehicle speed at that time.

By controlling the rotation of the motor 61, the worm gear 32a formed on the output shaft 62 of the motor 61 rotates the sector gear 24 that meshes with the worm gear 32a, and the link portion 21 that rotates together with the sector gear 24 rotates the pivot shaft 26. As a result, the arm member 17 is tilted so that the left end is downward (tL) as shown in FIG. At this time, the input shaft 12 is rotated, for example, by an angle θ in the anti-clockwise direction. ring 2
7.27 is steered in the opposite direction to the front wheels 6, 6, and the front/rear wheel steering angle ratio at this time is continuously changed in accordance with the tonne speed.

Next, when the tonnage speed increases beyond the initial setting value, the computer controller 6 reverses the motor 31, and as a result, the arm portion U' 17 &:I is reversed from the previous one as shown in Fig. 3(c). tilt, and as a result the pivot point p is at the center of the axis. If the input shaft 12 is rotated by an angle θ in the counterclockwise direction as described above, the ter(l) knot 5.25 is the third
In Figure (c), the broken line indicates 71 Me J, and the rear wheels 27.27 are also steered in the same direction as the +'+i1 wheels 6 and 6, and the rear wheels 27. The angular ratio changes continuously depending on the vehicle speed.

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 handling ability of the steered wheels. It's coming.

In addition, when driving at high speed, 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 11th wheel (7) The lateral acceleration of the vehicle can be adjusted to the intended value in a short time. This makes it possible to improve steering response and improve steering stability.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a perspective view showing the basic structure of a four-wheeled vehicle equipped with a steering device according to the present invention, and FIG. The enlarged perspective view and FIGS. 3(a), 3(b), and 3(c) are schematic 11-plane views showing the operating principle of the present steering system. In the drawing, 1 is a steering wheel, 5 is a front wheel steering tie, 6 is a front wheel, 9 is an operating sleeve, 12 is an input shaft, 14 is a swing shaft,
16 is the gear 31 Indian section, 17 is the arm assembly, 24 is the sector gear, 25M is the L rear wheel steering tie rond, 27 is the rear wheel, 31 is the motor, 62a is the gear, 66 is the computer, 64 is the 65 is a position sensor. Patent applicant Ki11 Giken Kogyo Co., Ltd. Agent: Ben Misaki Yoichi Shimoda Patent attorney: Kunihiko Ohashi

Claims (1)

[Claims] In a vehicle steering system in which the front wheels and the rear wheels are steered by steering operation of the steering wheel, a swing shaft is connected via a universal joint to the rear end of an input shaft that rotates in conjunction with the steering wheel. A joint assembly consisting of tie rods for rear wheel steering connected to the left and right sides of the swing shaft is fitted to the relative rotation axis F, and an arm whose length direction is in the width direction of the vehicle is fitted to the joint member. The members are fixed, and both ends of the arm member are connected to the vehicle body 111 via link parts, and one end of the arm member fil! A vehicle steering device comprising: a motor whose rotation is controlled according to IK heavy speed; and a worm gear mechanism interposed between the output shaft of the motor and the link portion of the arm member. .