KR101104512B1 - Method and Device for Controlling Rackbar Stroke with Detecting Switch of Snowchain and ECU Therefor - Google Patents

Abstract

The present invention relates to a method for adjusting the stroke of a rack bar using a snow chain detection switch, an apparatus, and an electronic control apparatus therefor.

The present invention provides an electric power assisted steering apparatus for a vehicle including a steering shaft and a motor, the gearbox including a rack bar provided at a lower end of the steering shaft and performing a linear movement according to a rotational movement by a steering operation of a driver ( GearBox); And a snow chain detection switch that controls the motor, detects whether the snow chain is mounted, and turns on / off the snow chain.If the snow chain detection switch is operated by mounting the snow chain, the steering angle of the driver's steering operation is greater than the set value If the steering angle is determined to be greater than or equal to the set value, the electric power assist steering device to adjust the stroke of the rack bar by using a snow chain detection switch comprising an electronic control device for controlling the current delivered to the motor to adjust the stroke of the rack bar To provide.

According to the present invention, the stroke adjusting device of the rack bar can control the stroke of the rack bar during steering depending on whether the snow chain is mounted, so that the vehicle is operated by securing the maximum steering angle without the snow chain mounted, but the snow chain is mounted. Only by reducing the maximum steering angle is effective to ensure stability.

 Electronic Controls, Rack Bars, Snow Chain Sense Switches, Steering

Description

METHOD AND DEVICE FOR CONTROLLING Rackbar Stroke with Detecting Switch of Snowchain and ECU Therefor}

1 is a configuration diagram of an electric power assist steering device of a vehicle according to the prior art,

2 is a block diagram of an electronic control apparatus according to a preferred embodiment of the present invention;

3 is a flow chart of a stroke adjustment method of a rack bar using a snow chain detection switch according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100: steering system 102: steering wheel

104: Steering 108: Tie Rod

112: wheel 118: rack bar

120: electronic control device 122: vehicle speed sensor

124: steering angle sensor 126: torque sensor

130: motor 140: transmission

210: calculation means 212: control means

220: snow chain detection switch

The present invention relates to a method for adjusting the stroke of a rack bar using a snow chain detection switch, an apparatus, and an electronic control apparatus therefor. More specifically, the electronic control device for adjusting the steering angle without changing the structure of the electric power assist steering device by adding a snow chain detection switch and logic to the electric power assist steering device to adjust the rack bar stroke. will be.

Steering system of a vehicle is a device for the driver to freely change the driving direction of the vehicle by turning the steering wheel. Therefore, the steering system is closely related to the front axle or the front wheel alignment, and it is a very important device for driving safety together with the brake system. In general, the steering system should be small so as to have a turning radius, the vehicle's turning should be stable at high speeds, and the steering operation should be light and free.

As automobiles become more advanced, low-pressure tires are used, and the ground resistance of the front wheels increases due to the automation of large vehicles, and the steering force of steering wheels is required, and power assisted steering assisting steering wheel steering power by installing a power source in the steering system. A device (Power Steering Appratus) has emerged.

As a power assisted steering device of a vehicle, a hydraulic power steering device using a hydraulic pressure of a hydraulic pump is generally used.However, since the 1990s, an electric power steering device using an electric motor has been used. It is becoming more and more common.

Conventional hydraulic power assisted steering system consumes energy regardless of whether the steering wheel is rotated by the hydraulic pump driven by the engine, which is the power source to assist the power, whereas the electric power assisted steering system rotates the steering wheel to increase torque. When generated, a motor driven by electrical energy provides steering assistance. Therefore, when the electric power assisted steering device is used, energy efficiency can be improved compared to the hydraulic power assisted steering device.

1 is a block diagram of an electric power assist steering device of a vehicle according to the prior art.

As shown in FIG. 1, an electric power assisted steering device generally includes a steering system 100 that extends from the steering wheel 102 to both wheels 112 and an auxiliary power mechanism that provides steering assistance power to the steering system. .

The steering system 100 comprises a steering shaft 104, one side of which is connected to the steering wheel 102 to rotate with the steering wheel 102 and the other side of which is connected to the pinion shaft 106. In addition, the pinion shaft 106 is connected to the rack bar 118 through the rack-pinion mechanism part, and both ends of the rack bar 118 are connected to both wheels 112 of the vehicle through the tie rod 108 and the knuckle arm 110. )

Since the rack-pinion mechanism part is formed by engaging the pinion gear part 114 formed on the pinion shaft 106 and the rack gear part 115 formed on one side of the outer circumferential surface of the rack bar 118 with each other, the driver rotates the steering wheel 102. ), The torque is generated in the steering system 100, and the wheel is steered through the rack-pinion mechanism part and the tie rod 108 by the generated torque.

The auxiliary power mechanism includes a vehicle speed sensor 122 that detects a vehicle speed and outputs an electrical signal proportional to the detected vehicle speed, a steering angle sensor 124 that detects a steering angle and outputs an electrical signal proportional to the detected steering angle, and a driver steer wheel Torque sensor 126 that senses torque applied to 102 and outputs an electrical signal proportional to the sensed torque, and each electrical signal sensed by vehicle speed sensor 122, steering angle sensor 124, and torque sensor 126. An electronic control unit (ECU) 120 that generates a control signal based on the control signal generated by the electronic control unit (ECU) 120, a motor 130 that generates auxiliary power by a control signal transmitted from the electronic control device 120, and It comprises a transmission 140 for transmitting the auxiliary power to the rack bar 118.

Therefore, in the electric power assist steering device of the vehicle, the torque generated by the rotation of the steering wheel 102 is transmitted to the rack bar 118 via the rack-pinion mechanism part, and the assist power generated by the motor in accordance with the torque is ball screwed by the transmission. It is formed to be delivered to the rack bar 118 via the portion 150. That is, the torque generated from the steering system 100 and the auxiliary power generated from the motor 130 are combined to move the rack bar 118 in the axial direction.

Referring to the operation principle of the electric power assisted steering device, the motor control current is calculated by the electronic control device 120 from the torque of the steering wheel 102, the vehicle speed, and the steering angle information detected by the sensor, and the motor 130 is actually The current value of the current is detected, the calculated motor control current is compared with the actual current of the motor, and the current corresponding to the difference is transmitted to the motor 130 to drive the motor 130 to assist the driver's steering operation. As the driver applies torque to the steering wheel 102, the current delivered to the motor 130 increases to assist the driver's steering operation.

The steering mode of the vehicle may be classified into a normal steering mode and a maximum steering mode according to the driver's steering operation. In general, the steering device of a vehicle is set to be capable of steering operation within a certain range. In the general steering mode, the driver operates the steering device within the steering limit of the steering device. (Full turn) means steering operation.

Steering angle in maximum steering mode is directly related to the radius of rotation of the vehicle when the driver makes a U-turn or parks. That is, the larger the maximum steering angle formed when the steering wheel is operated in the full steering mode with the Fulton, the greater the angle between the front wheels of the vehicle and the smaller the radius of rotation of the vehicle. Therefore, the maneuverability of the vehicle operation increases as the steering angle in the maximum steering mode increases.

Steering operation in the maximum steering mode is generally controlled so that the maximum steering angle with the snow chain attached to the tire in winter is smaller than the maximum steering angle without the snow chain for reasons of interference or stability with other parts. to be.

If the maximum steering angle is maintained in the normal state when the snow chain is mounted in winter, interference between the tire and other parts may occur due to the thickness (height) of the snow chain, and the friction force between the tire and the ground may be caused by the snow chain. Therefore, when a large steering angle is generated, the load applied to the entire vehicle and the steering apparatus is excessively increased, which may cause a breakdown. Therefore, it is necessary to set smaller than the maximum steering angle in a normal state.

On the other hand, if the maximum steering angle is set low throughout the year in preparation for the winter snow chain, this may reduce the running performance in the normal state. In other words, considering that the maximum steering angle control according to snow chain installation is limited to temporary deterioration of road conditions due to snow and ice in winter, the vehicle is operated by unnecessarily limiting the maximum steering angle. There are disadvantages.

Therefore, it is necessary to reduce the maximum steering angle by limiting the stroke of the rack bar by the thickness of the snow chain only when the snow chain is mounted. For this purpose, the gear bar is conventionally adjusted to add a gear to change the length between the stoppers. . In this case, a work requiring a structural change of the direct steering device is caused, and a problem arises in that the stroke of the rack bar is adjusted by operating a gear every time the snow chain is installed.

In addition, the prior art is to improve the maneuverability of the driver by increasing the steering angle with a VRS (Variable Rack Stroke) system. The VRS system reduces the minimum turning radius of the front wheels by changing the stroke of the steering wheel rack bar depending on whether or not snow chains are installed by utilizing the space secured inside the front wheels of four-wheel drive vehicles for winter tire chains. Works. Such a VRS system has a problem of expensive installation cost.

In order to solve this problem, the present invention, by adding only the snow chain detection switch and logic to the electric power assist steering device to adjust the stroke of the rack bar, to adjust the size of the steering angle without changing the structure of the electric power assist steering device. Its main purpose is to provide an electronic control device.

In order to achieve the above object, the present invention provides an electric power assisted steering apparatus for a vehicle including a steering shaft and a motor, the rack bar being provided at a lower end of the steering shaft and performing a linear movement according to a rotational movement by a driver's steering operation. Gearbox including; And a snow chain detection switch that controls the motor, detects whether the snow chain is mounted, and turns on / off the snow chain.If the snow chain detection switch is operated by mounting the snow chain, the steering angle of the driver's steering operation is greater than the set value If the steering angle is determined to be greater than or equal to the set value, the electric power assist steering device to adjust the stroke of the rack bar by using a snow chain detection switch comprising an electronic control device for controlling the current delivered to the motor to adjust the stroke of the rack bar To provide.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

2 is a block diagram of an electronic control apparatus according to a preferred embodiment of the present invention.

The electronic control device 120 generates a control signal based on the electrical signal transmitted from each sensor and the switch, and controls the motor 130 to assist the steering force. The vehicle speed sensor 122, the steering angle sensor 124, and the torque sensor 126 illustrated in FIG. 2 respectively detect the vehicle speed, the steering angle, and detect the torque applied to the steering wheel by the electronic controller 120. Send the relevant information. When the snow chain detection switch 220 recognizes the mounting of the snow chain and operates on, the electronic control device 120 determines whether the steering angle by the steering operation of the driver is greater than or equal to a predetermined value, If the steering angle is greater than or equal to the set value, the electronic control device controls the steering force assist function of the motor 130 to be blocked or reduced.

The electronic control device 120 may be configured to compare the steering angle information by the plurality of sensors with the set value when the snow chain detection switch 220 is operated, and to the motor 130 when the steering angle information is determined to be greater than or equal to the set value. Control means 212 for reducing, interrupting or applying reverse current.

The snow chain detection switch 220 can be set using logic without any structural change or input of equipment.

Although the snow chain detection switch 220 detects the mounting of the snow chain, a mechanical switch method is generally used, but the present invention is not limited thereto. However, the height of the tire is changed or the weight is changed according to the snow chain. Various methods may be used, such as a method of detecting noise.

In general, the steering device of a vehicle sets the steering angle of the front wheel in consideration of the installation of the snow chain, in the case of having a snow chain detection switch 220, usually off the snow chain detection switch 220 to turn off the snow chain To increase the stroke of the rack bar that transmits the driver's steering operation as much as possible, and to operate the vehicle by limiting the steering angle range by operating the snow chain detection switch 220 only when the snow chain is mounted in winter. do.

According to a preferred embodiment of the present invention, when the snow chain switch 220 is off, the steering angle range of -600 degrees to +600 degrees by the driver's steering wheel operation is possible, and the snow chain is mounted to detect the snow chain. When the switch 220 is turned on, the steering angle range is limited to -540 degrees to +540 degrees. When the steering angle is out of the set value ± 540 degrees by the steering wheel operation of the driver, the electronic control device 120 cuts off the steering force assist function of the motor 130. Here, the maximum steering angle of -600 degrees to +600 degrees when the snow chain is not mounted, or the maximum steering angle of -540 degrees to +540 degrees which is the control reference when the snow chain is mounted is just one example and may be set to other angles. will be.

3 is a flow chart of a stroke adjustment method of a rack bar using a snow chain detection switch according to the present invention.

The snow chain detection switch detects whether the snow chain is mounted on the tire (S310). Unlike setting the maximum steering angle of a general vehicle, in order to set the maximum steering angle based on a state where a snow chain is not mounted on a tire, it detects whether the snow chain is mounted.

In addition, to prevent the operation failure by limiting the stroke of the rack bar in the state in which the snow chain is mounted on the tire to prevent interference with other parts according to the thickness of the snow chain.

If the snow chain is not mounted, the snow chain detection switch is turned off (S320), and the maximum steering angle is steered by the driver without restriction of the set value (S330).

If the snow chain is not mounted, the maximum steering angle that the vehicle can have decreases the radius of rotation of the vehicle, thereby increasing the maneuverability of the vehicle. In other words, the larger the maximum steering angle in the maximum steering mode, the greater the angle between the front wheels of the vehicle, thereby reducing the radius of rotation of the vehicle required when the driver makes a U-turn or parking.

When the snow chain is mounted and the snow chain detection switch is turned on (S340), the electronic controller determines whether the steering angle by the steering operation of the driver detected by the steering angle sensor is greater than or equal to the set value (S350).

If the steering angle by the driver's steering wheel operation is determined to be equal to or greater than the set value, the electronic control device blocks the steering assistance function of the motor (S360).

Here, the blocking of the steering assistance function of the motor reduces or cuts off the current applied to the motor for steering assistance, as well as a reverse current value proportional to the excess steering angle or the excess torque for the steering operation exceeding the set value. It is a concept that includes the configuration to force the steering wheel to stop by applying.

When the snow chain is mounted on the tire, when the driver operates the steering wheel in the maximum steering mode, the stroke of the rack bar may cause interference with other parts depending on the thickness of the snow chain, which is prevented by the control of the electronic controller. . If the steering angle is determined to be greater than or equal to the set value, the electronic control unit blocks the steering force assist function of the motor to prevent malfunction due to interference with other components.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, the stroke adjusting device of the rack bar can control the stroke of the rack bar at the time of steering depending on whether the snow chain is mounted, thereby driving the vehicle by securing the maximum steering angle without the snow chain mounted. However, only by mounting the snow chain has the effect of ensuring the stability by reducing the maximum steering angle.

In addition, it is possible to operate the rack bar stroke control at a lower cost than making structural changes directly to the vehicle using only snow chain detection switches and logic.

Claims (2)

In the electric power assisted steering apparatus of a vehicle including a steering shaft and a motor, A gear box provided at a lower end of the steering shaft and including a rack bar configured to perform a linear motion according to a rotational motion by a driver's steering operation; And And a snow chain detection switch that controls the motor and detects whether the snow chain is mounted, and is on / off. When the snow chain detection switch is operated by the mounting of the snow chain, the steering angle is set by the driver's steering operation. An electronic controller for controlling the stroke of the rack bar by determining whether the steering angle is equal to or greater than a value and controlling the current transmitted to the motor when the steering angle is determined to be equal to or greater than a predetermined value; The electronic control apparatus includes a first method of reducing a steering auxiliary current value when the steering angle is determined to be equal to or greater than a set value, a second method of blocking a steering auxiliary current value, a steering angle or steering torque exceeding a set value. And controlling the current delivered to the motor in accordance with at least one of the third schemes of applying a reverse current proportional to. delete

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