JPS61278470A - Controller for power steering device - Google Patents

Abstract

PURPOSE:To make oil flow rate control characteristics selectable according to driver's preference, by installing a selecting device varying the circuit constant of a control circuit which performs such control as lessening an oil flow rate with increment of a car speed. CONSTITUTION:At the time of car driving, a car speed signal out of a car speed sensor 1 is fed to a solenoid drive circuit 4 via a voltage conversion circuit 2 and a smoothing amplification circuit 3. At this time, size of DC voltage to be secured out of the voltage conversion circuit 2 is the smaller, the larger in a car speed, while an oil flow rate to be fed to a power steering via a solenoid valve to be connected to output terminals SOL 1 and 2 is controlled to be large at low speed but small at high speed, respectively. The said oil flow rate is made being constant till it reaches the specified car speed V1, but this specified car speed V1 is made settable optionally by selecting a circuit constant of the voltage conversion circuit2, and selected with a characteristic select switch 9 turned on or off as well as a transistor 2q turned on or off.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a power steering device that controls oil flow rate in accordance with vehicle speed.

[Conventional technology]

Conventionally, a power steering device includes a vehicle speed sensor that generates a vehicle speed signal corresponding to the vehicle speed, and a control circuit that controls oil flow based on the vehicle speed signal generated by the vehicle speed sensor.
Control is performed so that the oil flow rate decreases as the vehicle speed increases.

That is, the oil flow rate is increased at low speeds when a large steering force is required, and is decreased at high speeds when the steering force is small, so that steering can be performed with an appropriate steering force over a wide vehicle speed range.

In this case, the oil flow rate is controlled by inserting an electromagnetic pulp into the oil passage, and decreasing the value of the output current supplied to the electromagnetic pulp as the vehicle speed increases, as shown in Figure 9, to control the opening of the electromagnetic pulp. This narrows the oil flow rate as the vehicle speed increases.

[Problem that the invention seeks to solve]

However, in such conventional control devices,
As shown in Figure 9, the output current supplied to the electromagnetic pulp changes in a one-to-one correspondence with changes in vehicle speed, so it is possible to produce only uniform changes in the vehicle speed-steering force characteristic. there were. Furthermore, this vehicle speed-steering force characteristic is fixed to a predetermined characteristic, making it difficult to respond to the driver's preferences.

[Means for solving problems]

The present invention has been made in view of the above-mentioned problems, and it is possible to change the oil flow rate control characteristics by changing the circuit constants of the control circuit.

[Effect]

Therefore, according to this device, it is possible to switch the oil flow rate control characteristics according to the driver's preference.

〔Example〕

Hereinafter, a control device for a power steering device according to the present invention will be explained in detail. FIG. 1 is a circuit diagram showing one embodiment of this device. In the figure, 1 is a vehicle speed sensor that generates a number of pulsed electric signals corresponding to the vehicle speed as a vehicle speed signal, 2 is a voltage conversion circuit that converts this vehicle speed signal into a DC voltage, 3 is a smoothing amplifier circuit, and 4 is a solenoid drive circuit, 5 is vehicle speed sensor 1
A first abnormality detection circuit 6 detects this short circuit, which detects this short circuit and the excessive current flowing to a solenoid valve (not shown) connected between the output terminals 5OLI and 5QL2 of the solenoid drive circuit 4. 8 is a second abnormality detection circuit that detects a disconnection in the solenoid pulse, T is a third abnormality detection circuit that detects a disconnection in the solenoid pulse, This is a solenoid drive stop circuit that cuts off the supply of power to the drive circuit 4.

The voltage conversion circuit 2 includes a resistor 2&~2g and a capacitor 2h~
2, diodes 2t to 211. )Ran resistor 2P+2
Consisting of q, output terminal 11L of vehicle speed sensor 1
The vehicle speed signal inputted through the motor generates a DC voltage whose voltage decreases as the vehicle speed reaches a high speed state. Further, the transistor 2q has its pace connected to a characteristic changeover switch 9, and this characteristic changeover switch 9
When the transistor 2q is turned on, the transistor 2q is turned off.

The smoothing amplifier circuit 3 includes resistors 31 to 3f and a capacitor 3g.

3h, thermistor 31. It is composed of an operational amplifier (hereinafter referred to as an operational amplifier) 3j, and is configured to perform non-inverting amplification and smoothing of the output signal of the voltage conversion circuit 2.

The solenoid drive circuit 4 is composed of resistors 4a to 4p%, capacitors 49 to 4t, diodes 4H to 4u, comparators 4M, and transistors 4V and 4X. Generates a pulse signal with a smaller ratio.1st
The abnormality detection circuit 5 includes resistors 5"a','5e~
5, capacitor s t + S g , diode 5
h1-comparator 51. The second current status detection circuit 6 includes a wax resistance am, 5b, and capacitors 6b to 6.
, a diode 6f, a comparator et. The third abnormality detection circuit T includes resistors 7 to 7f,
Capacitor Tw-7, diode Tj.

7, a comparator γt is also constructed. The solenoid drive stop circuit 8 includes a resistor 81 to 8g, a capacitor ah to 8j1, a transistor λ' and a diode 8t1.
It consists of a varistor 8m, a relay 8n1, and a contact 8p of the relay 8n.゛.

When the duty ratio of the current supplied increases, the opening degree of the valve increases and a structure is used that acts to increase the oil flow rate.Also, when no current is supplied to that point, the power steering The oil supply to the device is reduced.Incidentally, 10 is an abnormality warning lamp.

Next, the operation of the circuit configured as described above will be explained. When the automobile starts running, a pulsed vehicle speed signal generated from the vehicle speed sensor 1 is converted into a DC voltage by the voltage conversion circuit 2. Then, this DC voltage is smoothed and amplified by the slip-width circuit 3, and the larger the deviation, the smaller the voltage becomes. It generates a pulse signal. In other words, the current value supplied to the solenoid valve decreases as the vehicle speed increases, and the oil flow rate supplied to the power steering device via the solenoid valve is large at low speeds and small at high speeds. w, 1m. - Generally speaking, operational amplifiers have a dead zone in their output voltage relative to the power supply voltage. FIG. 2 shows the input/output characteristics of the operational amplifier 3j. In the figure, the horizontal axis is the input voltage, and the vertical axis is the output voltage υ, and the output voltage of the operational amplifier 3j changes linearly from the point when the input voltage drops by a predetermined voltage V relative to the power supply voltage Vcc supplied to the operational amplifier. . In other words, the output voltage is constant from the input voltage vCc to vac-v, i. In this embodiment, the connection point A in the voltage conversion circuit 2 is set to the same potential as the power supply potential of the operational amplifier, and the dead zone of the operational amplifier 3j is actively utilized. By doing this, the vehicle speed-output voltage characteristic of the operational amplifier 3j becomes as shown in FIG.

That is, the output voltage remains constant until the vehicle speed reaches the predetermined vehicle speed M1, and after reaching the predetermined vehicle speed M1, the output voltage decreases as the vehicle speed increases. As a result, the output current supplied to the solenoid valve via the solenoid drive circuit 4 has the same characteristics as shown in FIG. After the vehicle speed reaches , it decreases as the vehicle speed increases. In this embodiment, this predetermined vehicle speed V is set to 1
It was set at 0 to i5 remuneration/h. This is a beta car.

The steering wheel can be operated with the minimum steering force from the time the vehicle starts running until it reaches speeds of 10 to 15/h.
After reaching O-15rs+/Th, the steering force is adjusted in accordance with the vehicle speed in the same manner as before. 5 This vehicle speed 1
1 can be set arbitrarily by appropriately selecting the circuit constants of the voltage conversion circuit 20.The characteristic changeover switch 9 is turned on, the transistor 2q is turned off, and the resistor 2e is connected in parallel to the resistor 2d. By switching to the circuit state, the vehicle speed-output voltage characteristic of the voltage conversion circuit 2 becomes a gentle slope with Vce as the fulcrum, as shown by the dotted line in FIG.

Therefore, the insensitive vehicle speed range in the operational amplifier 3 is widened, and the output current supplied to the solenoid valve is as shown by the dotted line in FIG. 6. Virtual output current value I corresponding to Vce of
It begins to decrease with ce as a virtual fulcrum. Tsutb
By switching the characteristic changeover switch 9 from the off state to the on state or from the on state to the off state, the circuit constants in the voltage conversion circuit 2 are changed, and the control characteristics of the oil flow rate supplied to the power steering device are changed. It can be switched depending on the user's preference, driving conditions, etc. In this embodiment, the characteristic changeover switch 9 is connected between the base of the transistor 2q and the ground, but it may be connected between the base and the power supply potential.

Furthermore, in this embodiment, the oil flow rate control characteristics are switched by turning on and off the transistor 2q, but it does not necessarily have to be done by the transistor, and as shown in FIG. Connect the relay 11 to the connected characteristic changeover switch 9, and
The normally open contact 11a1 may be connected in series with the resistor 2e, and the oil flow rate control characteristics may be switched by turning the normally open contact 11a1 on and off. In this case, the reverse current blocking diode 2n of the voltage conversion circuit 2 in FIG. 1 can be omitted. Furthermore, the second normally open contact 11a of the relay 11 is connected to the resistor 3 of the smoothing amplifier circuit 3! By connecting resistor 12 in parallel via It changes by switching the circuit constants of the amplifier circuit 30. That is, by turning on the characteristic changeover switch 9, the normally open contacts 11&l and 11&! of the relay 11 are turned on. is closed, and the vehicle speed-output current characteristic (dotted line in FIG. 8) that is about to be supplied to the solenoid valve only by closing the normally open point 11as changes as the amplification factor of the operational amplifier 3j changes. As shown by the solid line in Figure 8, the value of the virtual output current value Ice is decreasing, and its slope is also at a predetermined point)
It becomes gentle with P as the fulcrum. Therefore, the insensitive vehicle speed range in the operational amplifier 3j is small, and the output current supplied to the solenoid valve has a characteristic that it gradually decreases from the time when the vehicle speed reaches V. This predetermined point) P can be determined by a feedback resistor that determines the amplification factor of the operational amplifier 3j, and can be set arbitrarily.

That is, by simultaneously switching the circuit constants of the voltage conversion circuit 2 and the amplifier circuit 30 by turning on and off the characteristic changeover switch 9, it is possible to obtain oil flow control characteristics that cannot be achieved by simply switching the circuit constants of the voltage conversion circuit 2. You will be able to do this. Note that in this embodiment, the voltage conversion circuit 2
Although the circuit constants of the smoothing amplifier circuit 3 are simultaneously switched using one characteristic changeover switch 9, the circuit constants of each circuit may of course be switched using independent switches. By doing so, four types of oil flow control characteristics can be obtained. Further, the number is not limited to four types, and it is possible to obtain a plurality of types of oil flow control characteristics. By doing this, the driver can freely select the oil flow control characteristics, that is, the steering force characteristics, according to his or her preferences and driving conditions, and the power steering system always meets the driver's wishes. can be provided.

In addition, in order to change the circuit constant, the normally open contact 11 of the relay 11
Although m1.11ax is used, it goes without saying that the normally closed contact of the relay 11 may also be used.

The above is the operation of the characteristic portion of the present invention, and the J%f detection circuit 5 to
Let me briefly explain the operation of T. That is, if the vehicle speed sensor 1 is short-circuited to the power supply while driving, the comparator 51
The output becomes the %HI level. As a result, the transistor 8k of the solenoid drive stop circuit 8 is turned on, the relay 8n is operated, and the contact 8p of the relay 8n is switched. Due to this switching operation, the power supplied to the solenoid drive circuit 4 is cut off, and the resistor lid
A power supply voltage is supplied to the base of the transistor 8 through the transistor 8, and this state is held. At the same time, the power supply voltage is also supplied to the abnormality warning lamp 10 and it lights up.

On the other hand, since the power is cut off, the solenoid drive circuit 4 no longer generates a pulse signal, so that no current is supplied to the solenoid valves connected to the output terminals 80L1 and 80L2. Therefore, since the amount of oil supplied from the solenoid valve to the power steering device decreases, the required steering force changes in the direction of increasing, and even if this abnormality occurs during high-speed driving, safety is maintained.

Abnormality detection circuit 6. Similarly, when an abnormality is detected at T, the output of comparator 8 gs T L becomes %H level, relay 8n operates, and safety during driving is maintained.

〔Effect of the invention〕

As explained above, according to the control device for the power steering device according to the present invention, the circuit constants of the control circuit can be changed to change the oil flow control characteristics, so that the oil flow rate can be changed as appropriate according to the driver's preference. The flow rate control characteristics can be switched, and a vehicle speed-steering force characteristic that meets the driver's needs can be obtained with a simple circuit configuration.

[Brief explanation of the drawing]

Figure 1 shows the vehicle speed vs. output current characteristics supplied to the solenoid valve of the power steering device control device according to the present invention, and Figure 6 shows the vehicle speed vs. output current supplied to the solenoid valve when the circuit constants of the voltage conversion circuit are changed. Fig. 7 is a circuit diagram showing another embodiment of the control device for this power steering device; Fig. 8 is a diagram showing changes in characteristics; Fig. 8 is a circuit diagram showing another embodiment of the control device for this power steering device; and Fig. 8 is a diagram showing the change in the power supply to the solenoid valve when the circuit constant of the amplifier circuit of this control device is changed. The changes in the vehicle speed vs. output current characteristics. 111-- Vehicle speed sensor, 2... Voltage conversion circuit, 3
...Smoothing amplifier circuit, 3j ... Φ operational amplifier,
4...Solenoid drive circuit, 9...1 characteristic changeover switch, 11th race...relay, 11at, 111!・・・
...Normally open contact.

Claims (1)

[Claims] A control device for a power steering system, comprising a vehicle speed sensor that generates a vehicle speed signal according to the vehicle speed, and a control circuit that controls oil flow rate to decrease as the vehicle speed increases, based on the vehicle speed signal generated by the vehicle speed sensor. A control device for a power steering device according to the invention, further comprising a switching means for changing a circuit constant of the control circuit to switch an oil flow control characteristic of the control circuit.