KR20090006525A - Electronically Controlled Hydraulic Power Steering - Google Patents

Abstract

The present invention relates to an electronically controlled power steering apparatus (ECPS).

The present invention provides a vehicle speed sensor for detecting a vehicle speed, an electronic control unit (ECU) for generating a control voltage corresponding to the vehicle speed, and a hydraulic steering auxiliary actuator for providing an auxiliary steering force by adjusting a flow rate according to the control voltage. In the electronically controlled hydraulic power steering apparatus including, the electronic control unit, when the condition that the steering control function is cut off, the lamp so that the control voltage output to the hydraulic control means may be gradually down (Down) Provided is an electronically controlled hydraulic power steering apparatus characterized by performing a ramp down function.

According to the present invention, it is possible to prevent a sudden change in the hydraulic pressure when a condition that the steering control function is cut off, it is possible to provide an improved steering feeling and to prevent the occurrence of abnormal noise of the vehicle.

Description

Electronically Controllable Power Steering Apparatus

The present invention relates to an electronically controlled power steering apparatus (ECPS). More specifically, the control voltage output from the electronic control unit to the hydraulic auxiliary steering means when the condition that the steering control function is cut off in the electronic control unit (ECU) provided in the electronically controlled hydraulic power steering device The present invention relates to an electronically controlled hydraulic power steering device for preventing sudden changes in hydraulic pressure by allowing it to be gradually down.

The power assist steering device for assisting the driver's steering wheel operation is largely classified into a hydraulic power assist steering device (HPS) and an electric power steering apparatus (EPS).

The hydraulic power assisted steering system provides the operator with a hydraulic pump connected to the rotating shaft of the engine to supply hydraulic fluid to the working cylinder connected to the rack bar. It is a device that enables steering operation with a small force. On the other hand, the electric power assist steering device includes a motor and an electronic control unit in a rack bar or column instead of a hydraulic pump and a working cylinder to assist the operation force by the power of the motor.

If the vehicle is traveling at low speed or at a standstill, a large auxiliary steering force is required because of the high frictional resistance between the tire and the road, but a large auxiliary steering force is required because the friction resistance between the tire and the road surface is small when the car is traveling at high speeds. It doesn't work. However, since the general hydraulic power assist steering device supplies the same auxiliary steering force in a low speed or high speed vehicle, the steering wheel becomes lighter than necessary in the case of the high speed, resulting in a poor steering stability.

In order to solve this problem, recently, an electronically controlled hydraulic power steering device has been introduced, which maintains steering stability at high speed by adjusting the auxiliary steering force according to the driving speed of the vehicle.

1 is a block diagram of a conventional electronically controlled hydraulic power steering apparatus.

In the electronically controlled hydraulic power steering device, when the steering shaft 104 rotates according to the driver's steering wheel 102 operation, the input shaft 108 connected by the universal joint 106 causes relative displacement with the pinion shaft (not shown). And a hydraulic power assist steering device in which hydraulic oil is selectively supplied to the left and right pressure chambers 122a and 122b of the operating cylinder 122 through the oil pump 120 to apply the auxiliary steering force to the rack bar 150. The basic principle of operation is the same.

 However, the electronically controlled hydraulic power steering device changes its operating state according to the speed of the vehicle, which is made by an electronic control unit (ECU) 140 and a hydraulic steering auxiliary actuator 110.

The vehicle speed detected by the vehicle speed sensor 130 is transmitted to the electronic control unit 140, and the electronic control unit 140 outputs a control voltage corresponding to the vehicle speed to the hydraulic steering auxiliary actuator 110.

The hydraulic steering assist actuator 110 is composed of a solenoid valve 112 and a flow path switching valve 114.

The solenoid valve 112 adjusts the flow rate of the working oil supplied from the working cylinder 122 to the flow path switching valve 114 by the control voltage transmitted from the electronic control unit 140.

When the hydraulic fluid is supplied to the hydraulic reaction force (not shown) in the flow path switching valve 114, the reaction force plunger (not shown) is brought into close contact with the input shaft 108 by hydraulic pressure, and thus the input shaft 108 is Rotation is regulated by the reaction force plunger.

The internal configuration of the hydraulic steering assist actuator 110 is a known configuration described in the Patent No. 723730, and further detailed description thereof will be omitted.

In the conventional electronically controlled hydraulic power steering apparatus having such a configuration, when the vehicle travels at a high speed, the solenoid valve 112 supplies hydraulic oil to the flow path switching valve 114 under the control of the electronic control unit, thereby providing a steering wheel ( 102) provides a stable steering feel at high speed.

In the conventional electronically controlled hydraulic power steering device, when a fail is detected by a vehicle speed sensor or a torque sensor, an error occurs in steering control, and thus the electronic control unit temporarily blocks the steering control function.

As a result, the control voltage output to the solenoid valve is drastically reduced, so that the solenoid valve is actuated rapidly and the flow rate supplied to the flow path switching valve is changed rapidly.

As a result, the weight of the steering wheel that the driver feels is changed drastically, resulting in a drop in the steering feeling or an abnormal noise.

This problem occurs even when the vehicle is turned off. For example, when the driver turns off the vehicle while the steering wheel is turned on, the steering control function of the electronic control unit is cut off and the weight of the steering wheel is lost. This drastically changes, which causes the steering wheel to bounce abruptly.

In order to solve this problem, the present invention provides a case in which a steering control function is blocked in an electronic control unit (ECU) provided in an electronic control power steering device (ECPS). It is an object of the present invention to provide an electronically controlled hydraulic power steering device for preventing a sudden change in the hydraulic pressure by allowing the control voltage output from the electronic control unit to the hydraulic auxiliary steering means to be gradually down.

In order to achieve the above object, the present invention provides a vehicle steering sensor for detecting a vehicle speed, an electronic control unit for generating a control voltage corresponding to the vehicle speed, and a hydraulic steering assist actuator for providing an auxiliary steering force by adjusting a flow rate according to the control voltage. In the electronically controlled hydraulic power steering apparatus comprising a, wherein the electronic control unit, when the condition that the steering control function is cut off, so that the control voltage output to the hydraulic control means can be gradually down (Down) Provided is an electronically controlled hydraulic power steering apparatus characterized by performing a ramp down function.

In addition, an electronically controlled hydraulic power steering apparatus including a vehicle speed sensor for detecting a vehicle speed, an electronic control unit for generating a control voltage corresponding to the vehicle speed, and a hydraulic steering auxiliary actuator for providing an auxiliary steering force by adjusting a flow rate according to the control voltage. The electronic control unit may include: a micro controller unit (MCU) for generating the control voltage; An output port for outputting the control voltage to the hydraulic steering assist actuator; And a capacitor connected between the control means and the output port so that the control voltage outputted to the hydraulic control means may be gradually down when a condition that steering control function is cut off occurs. It provides an electronically controlled hydraulic power steering apparatus comprising a.

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 the detailed description of the related well-known configuration or function is obvious to those skilled in the art or may obscure the gist of the present invention, the detailed description thereof will be omitted.

2 is a block diagram of an electronically controlled hydraulic power steering apparatus according to a first embodiment of the present invention.

The electronically controlled hydraulic power steering apparatus according to the first preferred embodiment of the present invention includes a torque sensor 210, a vehicle speed sensor 220, an electronic control unit 230, and a hydraulic steering auxiliary actuator 240.

The torque sensor 210 detects torque generated according to the driver's steering wheel operation, and the vehicle speed sensor 220 detects the vehicle speed.

The torque and the vehicle speed sensed by the torque sensor 210 and the vehicle speed sensor 220 are output to the electronic control unit 230, and the electronic control unit 230 generates a control voltage corresponding to the torque and the vehicle speed to generate a hydraulic steering auxiliary actuator. Transfer to the air 240.

The hydraulic steering auxiliary actuator 240 adjusts the hydraulic pressure according to the control voltage to provide the auxiliary steering force, the operation principle and configuration of which are described above.

In particular, the electronically controlled hydraulic power steering apparatus according to the first embodiment of the present invention is equipped with a program for performing a ramp down function in the electronic control unit 230.

The electronic control unit 230 causes the control voltage transmitted to the hydraulic steering auxiliary actuator 240 to gradually decrease gradually without executing a program when the condition that the steering control function is cut off occurs.

Here, the condition in which the steering control function is cut off includes a case in which a failure occurs in the vehicle speed sensor 210 or the torque sensor 220, a case in which starting is turned off, and whether or not a failure occurs is an electronic control unit. In operation 230, it is determined by comparing whether the vehicle speed and torque are outside the normal range, which is a function generally mounted in the electronic control unit 230, and thus, detailed description thereof will be omitted.

3 is a block diagram of an electronically controlled hydraulic power steering apparatus according to a second embodiment of the present invention.

The electronically controlled hydraulic power steering apparatus according to the first embodiment of the present invention is configured to gradually reduce the control voltage output to the hydraulic steering auxiliary actuator by mounting a program to perform a ramp down function in the electronic control unit 230. The second embodiment is distinguished from the first embodiment in that it is configured to use a capacitor which serves to charge and discharge electrical energy.

In the second embodiment of the present invention, since the torque sensor 310, the vehicle speed sensor 320, and the hydraulic steering assist actuator 340 have the same function and configuration as the first embodiment, the electronic control unit 330 will be described below. The configuration will be described.

The electronic control unit 330 includes a micro controller unit (MCU) 332, a capacitor 334, and an output port 336.

The microcontroller unit 332 performs a steering control function by generating and outputting a control voltage corresponding to the torque transmitted from the torque sensor 310 and the vehicle speed sensor 320 and the vehicle speed, and the output port 336 is a microcontroller unit. The control voltage generated by 332 is transmitted to the hydraulic steering assist actuator 340.

The capacitor 334 is connected between the microcontroller unit 332 and the output port 336, and when the condition that the steering control function is cut off in the microcontroller unit 332 occurs, during the period during which steering control is being performed. By discharging the charged electrical energy, the control voltage transmitted to the hydraulic steering assist actuator 340 gradually decreases.

According to the preferred embodiment of the present invention described above, even when a vehicle fails, such as a vehicle speed sensor or a torque sensor, or when starting is turned off, the control voltage output from the electronic control unit to the hydraulic steering assist actuator gradually decreases, It is possible to prevent sudden changes in the weight of the steering wheel by preventing a sudden change in the hydraulic pressure that provides the auxiliary steering force, which not only provides the driver with improved steering feeling, but also occurs due to a sudden change in the hydraulic pressure. There is an effect that can prevent the abnormal noise.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes 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.

1 is a configuration diagram of a conventional electronically controlled hydraulic power steering device

Figure 2 is a block diagram of an electronically controlled hydraulic power steering apparatus according to a first embodiment of the present invention

3 is a block diagram of an electronically controlled hydraulic power steering apparatus according to a second embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

210, 310: torque sensor 220, 320: vehicle speed sensor

230, 330: electronic control unit 240, 340: hydraulic steering auxiliary actuator

332: microcontroller unit 334: capacitor

336: output port

Claims (4)

Electronic including a vehicle speed sensor for detecting a vehicle speed, an electronic control unit (ECU) for generating a control voltage corresponding to the vehicle speed, and a hydraulic steering auxiliary actuator for providing an auxiliary steering force by adjusting a flow rate according to the control voltage. In controlled hydraulic power steering (ECPS: Electronic Control Power Steering Apparatus), The electronic control unit performs a ramp down function so that the control voltage outputted to the hydraulic control means may be gradually down when a condition that steering control function is cut off occurs. An electronically controlled hydraulic power steering device. Electronic including a vehicle speed sensor for detecting a vehicle speed, an electronic control unit (ECU) for generating a control voltage corresponding to the vehicle speed, and a hydraulic steering auxiliary actuator for providing an auxiliary steering force by adjusting a flow rate according to the control voltage. In controlled hydraulic power steering (ECPS: Electronic Control Power Steering Apparatus), The electronic control unit, A micro controller unit (MCU) for generating the control voltage; An output port for outputting the control voltage to the hydraulic steering assist actuator; And Capacitor connected between the control means and the output port to allow the control voltage outputted to the hydraulic control means to be gradually down when a condition that steering control function is cut off occurs. Electronically controlled hydraulic power steering, comprising a. The method according to claim 1 or 2, The condition that the steering control function is cut off is an electronically controlled hydraulic power steering apparatus, characterized in that when the vehicle (fail) occurs. The method according to claim 1 or 2, The condition that the steering control function is cut off is an electronically controlled hydraulic power steering apparatus, characterized in that the case that the start of the vehicle is off (OFF).

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