JPH0322351B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a steering force control device for a power steering device used in automobiles, etc., and particularly to a steering force control device for a power steering device used in an automobile, etc. The present invention relates to a control device.

[Prior art]

The above-mentioned steering force control device, as shown in FIG.
The steering hydraulic pressure (PC) supplied to the power cylinder 3 via the power steering and control valve 2 is taken out by the pump 1, and a pulse corresponding to the vehicle speed signal from the vehicle speed sensor 8 is sent via the electrical system control device 7. By controlling the proportional solenoid 6, the hydraulic pressure control valve 5 is controlled to control the hydraulic pressure (PC), and this controlled hydraulic pressure (PR) is transferred to the reaction force chamber 4 provided in the control valve 2.
and generates a steering force on the steering wheel according to the steering load and vehicle speed.

However, in the process of manufacturing a vehicle equipped with the above-mentioned steering force control device or when maintaining it at a service shop in the market, it is necessary to check each vehicle to confirm that the steering force increases as the vehicle speed increases. It is often difficult to run. In addition, checking the steering force at high speed using a special and difficult-to-handle measuring device such as an oscillator, especially at a service shop in the market, has the disadvantage of increasing the burden on the maintenance engineer.

[Summary of the invention]

This invention solves the above-mentioned drawbacks and provides electrical system control that allows the steering force at high speed to be checked while the vehicle is stopped by simply providing a check terminal and connecting a variable or fixed resistor between the terminal and ground. It provides equipment.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. In FIG. 2, 6 is a proportional solenoid, 8 is a vehicle speed sensor, 9 is a key switch, 10 is a battery mounted on the vehicle, 11 is a switch or connector connected to a check terminal, and 12 is a high speed state check resistor. Reference numeral 7 denotes an electrical control device which uses a battery 10 as a power source, receives a signal from a vehicle speed sensor 8, outputs a current inversely proportional to the vehicle speed, and drives the proportional solenoid 6, and has the following internal configuration. 701 is a one-shot multivibrator which outputs a constant width pulse (FIG. 3b) by inputting a pulse frequency (FIG. 3a) corresponding to the vehicle speed of the vehicle speed sensor 8, and 702 is the output of the one-shot multivibrator 701. Turn on/off by receiving
NPN type transistor, 703 is a charging resistor,
704 is a discharge resistor, 713 is a charge/discharge resistor,
705 is a capacitor that forms a charging/discharging circuit with resistors 703, 704, and 713, and outputs a voltage inversely proportional to the pulse frequency of the vehicle speed sensor 8 (Fig. 3 c) to point c in Fig. 2; 706 is a capacitor at both ends of the capacitor 705; This is an error amplification circuit that operates using a voltage, that is, an F/V conversion voltage of the vehicle speed as a reference voltage.

707 PWMs the output waveform to solenoid 6
(Pulse Width Modulation) The fundamental frequency (500
This is a triangular wave (or sawtooth wave) oscillation circuit (~1000Hz). 708 is a PWM circuit that compares the output voltage of the error amplification circuit 706 and the output voltage of the triangular wave oscillation circuit 707, and outputs a PWM wave having a pulse frequency of the oscillation circuit 707 with a pulse width proportional to the output voltage of the error amplification circuit 706. , 709 is a proportional solenoid drive circuit that can flow a drive current to the proportional solenoid 6, 710 is a shunt resistor inserted in series between the proportional solenoid 6 and the ground to detect the drive current, and 711 is a shunt resistor of the shunt resistor 710. Error amplification circuit 70 detects and amplifies the voltage drop occurring across both ends.
712 is a constant voltage circuit that supplies a stabilized power source (5 to 8 V) to each circuit except the proportional solenoid drive circuit 709.

The operation of the apparatus of the present invention configured as above will be explained. First, when the key switch 9 is turned on while the car is stopped (switch 11 is off), that is, when the car is idling, power is directly supplied from the battery 10 to the proportional solenoid drive circuit 709 via the key switch 9, and other circuits are supplied to the constant voltage circuit 712. A regulated power source is supplied via the .

Therefore, a stabilized voltage is also applied to the resistors 703, 713, and 704, so the point c is applied to the resistors 703, 704, and
A voltage divided by 713 and 704 is applied. This voltage becomes the reference voltage of the error amplification circuit 706, and the maximum current (approximately 1A) is applied to the proportional solenoid 6.
is commanded, and equilibrium is achieved at the point where the output voltage of the solenoid current detection circuit 711 matches the reference voltage, that is, the point where the current flowing through the solenoid 6 becomes approximately 1A.
Therefore, the hydraulic reaction force becomes minimum and the steering force becomes small. Next, when the car starts running and the vehicle speed sensor 8 starts outputting a vehicle speed pulse, a vehicle speed pulse having a waveform as shown in FIG. 3a is applied to point a. In response to this signal, the one-shot multivibrator 701 outputs a constant width pulse having a waveform as shown in FIG. 3b at point b. Therefore, for each pulse, the transistor 702 becomes conductive for a certain period of time, and the capacitor 70
The charges stored in capacitor 5 are discharged via resistor 713 and transistor 702, and the average potential across capacitor 705 decreases. That is, the error amplification circuit 706
Since the reference voltage of solenoid 6 decreases, the energizing current of solenoid 6 also decreases and becomes balanced, and the hydraulic reaction force increases in accordance with the vehicle speed, making it possible to obtain stable steering force even though the steering wheel is heavy. ing.

Therefore, when performing a steering force confirmation test under high-speed running conditions on a vehicle equipped with a power steering system that has characteristics such that the steering reaction force gradually increases with respect to vehicle speed as detailed above, When the vehicle is stopped and the switch 11 is turned on and the variable resistor 12 is decreased, the vehicle speed characteristic at point c will be as shown by the broken line B in Figure 3c, and the solenoid current will be lower than the solid line A when the switch 11 is off. decreases, and a reference voltage equivalent to that in the high-speed state is output to the error amplification circuit 706.
The current flowing through the proportional solenoid 6 is reduced, the hydraulic reaction force is increased, and a state of heavy steering force corresponding to a high-speed driving state can be realized.

In this embodiment, a variable resistor is connected to the check terminal via a switch 11 so that the high-speed state can be changed as appropriate. By incorporating a fixed resistor corresponding to the high-speed state inside and grounding one end of the above connector,
Although it is a single point in a high-speed state, it can be realized with a simpler configuration.

Further, although the discharge switching element transistor 702 is used, the same effect can be obtained by using a comparator instead.

〔Effect of the invention〕

As described above, the present invention has the advantage that it is possible to carry out a steering force check in a high-speed running state while the vehicle is stationary with a simple configuration and the addition of very inexpensive parts.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a steering force control device to which this invention is applied, FIG. 2 is a block diagram of an electrical system control device of the steering force control device of this invention, and FIG. 3 is a block diagram of each part of the device according to this invention. FIG. 3 is a characteristic diagram showing characteristics. In the figure, 6 is a proportional solenoid, 7 is an electric control device, 8 is a vehicle speed sensor, 9 is a key switch, 10 is a battery, 11 is a switch, 12 is a variable resistor,
701 is a one-shot multivibrator, 7
02 is a transistor, 703, 704, 713 are resistors, 705 is a capacitor, 706 is an error amplifier circuit, 707 is a triangular wave oscillation circuit, 708 is a PWM circuit, 709 is a proportional solenoid drive circuit, 710 is a shunt resistor, 711 is a solenoid current detection The circuit 712 is a constant voltage circuit.

Claims (1)

[Claims] 1. A control signal corresponding to the vehicle speed is applied to the proportional solenoid, and the energizing current flowing through the coil of the proportional solenoid is adjusted to control the hydraulic control valve to obtain an appropriate steering reaction force hydraulic pressure. In such a power steering system, an F/V conversion circuit inputs a vehicle speed signal from a vehicle speed sensor and outputs an output voltage inversely proportional to the vehicle speed, and an F/V conversion circuit that corresponds to the output of this F/V conversion circuit and the current flowing through the proportional solenoid. An error amplifier circuit that compares the feedback voltage with the feedback voltage and amplifies the difference, a proportional solenoid drive circuit that controls the proportional solenoid based on the output of this error amplifier circuit, a terminal that draws the output of the F/V conversion circuit to the outside, and this terminal. A high-speed running state setting resistor and a switch means are provided, and the switch means connects the resistor to reduce the output voltage of the F/V conversion circuit, so that there is no vehicle speed signal from the vehicle speed sensor. A steering force control device for a power steering system that can obtain a steering reaction force similar to that in high-speed driving conditions. 2. A steering force control device for a power steering device according to claim 1, wherein the resistance is a variable resistance so that the high speed state can be varied in various ways.