KR20030006345A - Power Steering for automobile - Google Patents

Abstract

PURPOSE: A power steering system for a vehicle is provided to prevent the deviation of the rotational center of inner and outer wheels corresponding to the change of the vehicle speed by independently controlling the steering angles of the inner and outer wheels. CONSTITUTION: A rack(7) is movably installed in a cylindrical housing(4). Tie bars(8) are placed in both sides of the rack. The housing embeds a torque sensor(5) and a first electric motor(6) for operating the rack. A vehicle speed sensor(9) is installed in the speedometer in an instrument panel. A first cylinder(11) and a second cylinder(12) for correcting the steering angle via the rack are installed in both sides of the housing.

Description

Power steering device for automobiles {Power Steering for automobile}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering apparatus for automobiles, and more particularly, to a power steering apparatus for automobiles in which the turning centers of the inner and outer rings coincide.

As is well known, the steering device of the vehicle is a device for allowing the driver to arbitrarily manipulate the driving direction of the vehicle, and the power steering device uses a power booster to lighten the steering wheel operation, particularly at low speeds. It is possible to control the direction of movement of the vehicle with little force.

These power steering devices can be roughly classified into hydraulic power steering devices and electric power steering devices. The hydraulic power steering devices operate a hydraulic pump by the power of the engine and reduce the driver's steering force by using the hydraulic power of the hydraulic pump. The electric power steering device is to be controlled electronically to solve the problem of reducing the steering force during high-speed driving, which is a disadvantage of the conventional hydraulic power steering device.

That is, when the vehicle is driving at high speed, the traction with the road surface decreases. The electric power steering system senses the driving speed of the vehicle, and at the low speed, the steering wheel of the steering wheel is moderately lightened and the steering wheel is heavy when driving at high speed. Prevent accidents caused by operation.

1 and 2 of the accompanying drawings shows the configuration of a rack assist type electric power steering device, when the driver operates the steering wheel (1) the torque sensor (5) to the rotation of the steering wheel (1) Detects the torque applied to the shaft 3 and transmits the torque to the electronic control unit (ECU) (not shown), and the electronic control unit (ECU) detects the traveling speed of the vehicle and the torque sensor (not shown). By operating the electric motor 6 in accordance with the amount of steering wheel rotation input from 5) to operate the rack 7 by the required amount to assist the steering force.

However, the conventional power steering devices as described above typically follow the Ackerman-jantaud type steering principle as shown in FIG. 3, and the steering angle of the inner and outer wheels shown in actual vehicle driving is shown in FIG. As shown in the figure, as the driving speed increases, the difference between the Ackerman-Soil theoretical steering angle is different.

Therefore, the linkage type steering angle control makes it difficult to attain the ideal center of rotation of the inner and outer wheels when turning the vehicle at varying vehicle speeds. It will cause various problems.

Accordingly, the present invention has been made to solve the above problems, to provide a power steering apparatus for an automobile to prevent the turning center is shifted according to the change in vehicle speed by independently controlling the steering angle of the inner and outer wheels in front of the vehicle. The purpose is.

1 is a view showing the configuration of a conventional electric power steering apparatus

FIG. 2 is a view illustrating a gear assembly structure of the electric power steering apparatus of FIG. 1. FIG.

3 is a diagram showing the relationship between the inner and outer wheel steering angle of the vehicle by a conventional electric power steering device.

4 is a graph showing the steering angle relationship of FIG.

5 is a configuration diagram showing the configuration of the electric-hydraulic power steering apparatus according to the present invention

* Description of reference numerals in the main parts of the drawings *

1-Steering Wheel 3-Axis

4-Housing 5-Torque Sensor

6-First Motor 7-Rack

8-tie bar 9-vehicle speed sensor

11-1st cylinder 12-2nd cylinder

15-2nd Motor P-Pump

R-Oil Storage ECU-Electronic Control Unit

In order to achieve the above object, the present invention provides a hollow cylindrical housing, a rack that is internally movable to the housing and is coupled to tie bars respectively coupled to tires on both sides of the vehicle, and detects a traveling speed of the vehicle. A vehicle speed sensor to be transmitted to a control unit (ECU), a torque sensor installed at one side of the housing so as to be connected to a steering wheel, and detecting a torque according to a driver's steering wheel operation to be transmitted to the electronic control unit (ECU); A first electric motor having a pinion engaged with the rack and operating according to the control value of the electronic control unit according to the vehicle speed and torque input from the vehicle speed sensor and the torque sensor and moving the rack; It provides a power steering device for a vehicle is provided with a steering angle correction means for correcting the inner and outer ring steering angle by moving the tie bars independently. .

Here, the steering angle correction means, a pair of cylinders installed to be coupled to both ends of the rack and each tie bar at both ends of the housing, a pump for supplying oil to the cylinder, and an oil reservoir for supplying oil to the pump And a second electric motor connected to the electronic control unit (ECU) and the pump to control the operation of the pump according to the control of the electronic control unit.

In addition, according to the present invention, the electronic control unit by the operation of the second electric motor stops the operation of the second electric motor when the abnormality occurs in the main control system for operating the first electric motor to operate the steering manually when an abnormality occurs in the main control system This is made possible.

Hereinafter, preferred embodiments of the power steering apparatus according to the present invention will be described in detail with reference to the accompanying drawings, and in the following description, the same or similar components as those of the conventional power steering apparatus will be given the same reference numerals and will be described in detail. Description is omitted.

5 is a configuration diagram showing the configuration and operation of the electric-hydraulic power steering apparatus according to the present invention, wherein the rack 7 is installed in the elongated cylindrical housing 4 of the power steering apparatus so as to be movable left and right, At both ends of the rack 7 are tie bars 8 which are respectively coupled with tires (not shown) on both sides of the front of the vehicle.

The housing 4 has a torque sensor 5 for detecting torque transmitted to the shaft 3 as the driver operates the steering wheel 1 (see FIG. 1), and a pinion engaged with the rack 7 (not shown). And a first electric motor 6 which is driven by the control of the electronic control unit ECU of the vehicle and which operates the rack 7 left and right.

The speedometer in the instrument panel of the vehicle is provided with a vehicle speed sensor 9 which detects the traveling speed of the vehicle and transmits it to the electronic control unit ECU.

On the other hand, both ends of the housing (4) to control to adjust the steering angle by the rack (7) by independently operating each tie bar (8) according to the driving speed of the vehicle and the steering wheel (1) operating force of the driver, etc. As the steering angle correction means, a first cylinder 11 and a second cylinder 12 are provided, respectively.

Each of the first cylinder 11 and the second cylinder 12 is connected to a pump P to receive a predetermined oil by the operation of a flow control valve (not shown) in the pump P, and the pump P ) Is connected to and operated by a second electric motor 15 controlled by an electronic control unit (ECU). Unexplained symbol R represents an oil reservoir.

The power steering device configured as described above is controlled by the main control system in which the steering angle is controlled by the first electric motor 6 and the hydraulic system of the second electric motor 15 and the pump P, and the auxiliary control corrects the steering angle. Can be distinguished by lineage.

In the main control system, information such as the vehicle traveling speed detected by the vehicle speed sensor 9 and the torque applied according to the driver's steering wheel 1 detected by the torque sensor 5 during the progress of the vehicle are electronic. When delivered to the control unit ECU, the electronic control unit ECU operates the first electric motor 6 according to a preset control value.

Accordingly, the pinion (not shown) of the first electric motor 6 controls the steering angle by moving the tie bar 8 by moving the rack 7 in the housing 4 in a desired direction.

At this time, the auxiliary control system matches the turning center by controlling the actual steering angle to approximate the theoretical steering angle according to the ackerman-jantoud type steering principle described in the prior art.

Specifically, the steering angle control by the main control system is performed as described above, and the electronic control unit ECU controls the operation of the second electric motor 15 according to the detected vehicle traveling speed and torque. By controlling the operation of the pump P, the flow control valve (not shown) of the pump P supplies an appropriate amount of oil to each of the first cylinder 11 and / or the second cylinder 12 so that Fine adjustment of the tie bar 8 controls the steering angle.

On the other hand, when an abnormality occurs in the main control system operated by the first electric motor 6 while the vehicle is running, the electronic control unit ECU stops the operation of the second electric motor 15 so that the pump P ) And manually switch the steering angle control by deactivating the hydraulic system.

As described above, according to the present invention, since the inner and outer rings of the vehicle can be independently controlled by the hydraulic steering system of the auxiliary control system together with the electric steering system of the main control system of the power steering system, even if the traveling speed of the vehicle changes. As the turning centers of the inner and outer rings of the vehicle coincide, the tire wear is reduced, the service life is increased, and the turning stability is improved.

Claims (3)

A hollow cylindrical housing, a rack which is movably installed in the housing, a rack coupled to tie bars respectively coupled to both tires of the vehicle, and a vehicle speed that senses the traveling speed of the vehicle and transmits it to the electronic control unit (ECU). It is provided with a sensor, a torque sensor installed on one side of the housing so as to be connected to the steering wheel of the vehicle, detects the torque according to the steering wheel operation of the driver and transmits it to the electronic control unit (ECU), and a pinion engaged with the rack of the housing. A first electric motor that operates under the control of the electronic control unit according to the vehicle speed and torque input from the vehicle speed sensor and the torque sensor and moves the rack, and is respectively coupled to both ends of the rack to independently move the tie bars. An automotive power steering apparatus comprising a steering angle correction means for correcting the inner and outer wheel steering angles. 2. The steering angle correction means according to claim 1, wherein the steering angle correction means includes a pair of cylinders installed at both ends of the housing and coupled to both ends of the rack and respective tie bars, a pump for supplying oil to the cylinder, and a supply of oil to the pump. And a second electric motor connected to an oil storage unit, an electronic control unit (ECU) and a pump to control the operation of the pump according to the control of the electronic control unit. 3. The motorized power steering of claim 2, wherein the electronic control unit stops the pump operation by stopping the operation of the second electric motor when an abnormality occurs in the main control system for operating the first electric motor. Device.