JPS63255172A - Power steering device - Google Patents

Abstract

PURPOSE:To restrain the lowering of a storage battery voltage and sufficiently ensure steering assisting force by cutting off the feeding of power to a vehicle loaded load having large power consumption except a steering assisting electric motor when the sudden steering of wheels is detected. CONSTITUTION:An electric motor 42 is controlled by a controller 12 into which the outputs of detecting means such as a steering sensor 1, a vehicle speed sensor 2, an engine speed detector 3, etc. are inputted to control the discharging flow rate of an oil pump 41 which is driven by the electric motor 42, thereby controlling steering assisting force. In such a power steering device, when a vehicle is judged to be in a sudden steering condition with a vehicle speed detected by the vehicle speed sensor 2 being below a defined value (approx. 10km/h) while a steering speed obtained by the output of the steering sensor 1 being above a defined value (approx. 250deg/sec), the electrification to a relay 14 is cut off. Thereby, the drive of a sub-fan 15 for cooling a radiator is stopped to enable the electric motor 42 to be driven with a large electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power steering device that performs power steering of a vehicle using an electric motor.

[Conventional technology]

In recent years, power steering devices have been used in steering devices for automobiles and the like to perform light and quick steering operations and to reduce driver fatigue.

Generally speaking, when talking about power steering devices, a power steering system is mainly used, which enables driving with an appropriate steering force by driving an oil pump using an engine as a power source. However, in such power steering systems, the energy consumption tends to increase as the engine speed increases.Recently, in order to reduce this energy consumption, an electric motor is used as the power source to drive the oil pump. An electric motor-driven pump type power steering system has been developed.

In other words, in this electric motor-driven pump type power steering system, the rotation speed of the electric motor is controlled according to the vehicle speed and the amount of steering, and the oil flow discharged from the oil pump is changed, so that a large steering force is not required. When driving at low speeds, the amount of oil discharged is increased, and when driving at high speeds, where a small steering force is required, the amount of oil discharged is decreased, allowing steering to be performed with appropriate steering force over a wide range of vehicle speeds. . Such an electric motor-driven pump type power steering system is disclosed in, for example, Japanese Patent Laid-Open No. 56-99859.

[Problem that the invention seeks to solve]

However, in such an electric motor-driven pump type power steering system, when sudden steering is performed, especially when driving at low speed, the discharge pressure of the oil pump increases. In order to maintain or increase the discharge flow rate from the oil pump, the electric motor requires a large amount of power. Therefore, there is a problem in that the total power consumption increases together with the power consumption of other auxiliary devices mounted on the vehicle, and the pantry voltage decreases. In other words, as a result of this decrease in battery voltage, the rotation speed of the electric motor decreases and the flow rate of oil discharged from the oil pump decreases, resulting in the problem that sufficient steering assist force cannot be obtained during sudden steering. there were.

[Means for solving problems]

The present invention has been made in view of these problems, and is designed to detect sudden steering in a vehicle, and to detect sudden steering in a vehicle. It is designed to cut off the power supply to the mouth.

[Effect]

Therefore, according to the present invention, the total power consumption is reduced during sudden steering.

〔Example〕

Hereinafter, the power steering device according to the present invention will be explained in detail. The figure is a system configuration diagram of an electric motor-driven pump type power steering system showing one embodiment of this power steering device. In the figure, l is a steering sensor that sends out a pulsed electrical signal according to the amount of steering, 2 is a vehicle speed sensor that sends out a pulsed electrical signal depending on the vehicle speed, and 3 is an engine rotation sensor that detects whether or not the engine is rotating. 4 is an oil pump 41 and an electric motor 4 that drives this oil pump 41.
2 is an electric motor-driven pump, 5 is a motor pump heater that increases the oil temperature in the oil pump 41;
6 is a temperature sensor arranged near the oil pump 41 to relatively detect the oil temperature in this oil pump 41; 7 is an abnormality warning lamp that warns of abnormality in this system; 8
is the battery, and 9 is the ignition switch. The electric motor 42 has one end connected to the positive polarity side of the battery 8,
The other end is connected to the collector of the power transistor 10, and the emitter of the power transistor 10 is connected to the resistor R.
It is grounded via 1. A flywheel diode 11 is connected in parallel to the electric motor 42, and the base of the power transistor 10 is connected to the P of the controller 12.
Connected to the WM terminal.

The controller 12 includes a steering sensor l, a vehicle speed sensor 2.
Signals from the engine rotation detector 3 and temperature sensor 6 are input, and when a low oil temperature state in the oil pump 41 is detected via the temperature sensor 6, the coil 131 of the relay 13 is energized. By energizing and closing the normally open contact 132, power is supplied to the motor pump heater 5. Also, by detecting the steering condition based on signals inputted through the vehicle speed sensor 2 and the steering sensor l, selecting a pulse width modulation characteristic suitable for this steering condition, and driving the power transistor lO via the PWM terminal. By changing the average voltage supplied to the electric motor 42, the flow rate of oil discharged from the oil pump 41 is controlled. That is, when the vehicle speed is determined to be less than 1Qkm/h based on the signal from the vehicle speed sensor 2, when steering is detected based on the signal from the steering sensor 1, the power transistor 10 operates at a duty ratio of 100%. As a result, the electric motor 42 is driven at maximum rotation, the flow rate of oil discharged from the oil pump 41 is maximized, and the auxiliary steering force applied to the steering wheel is maximized. On the other hand, if the vehicle speed is determined to be 10 kll/h or more based on the signal from the vehicle speed sensor 2, the pulse width modulation characteristics are set such that the drive duty ratio of the power transistor 10 becomes smaller as the vehicle speed increases. As a result, the rotational speed of the electric motor 42 is reduced, and the flow rate of oil discharged from the oil pump 41 is reduced. That is, as the vehicle speed increases, the auxiliary steering force applied to the steering wheel decreases. In addition, 14
is a relay that drives the sub-fan 15 for cooling the radiator, and when the coil 141 is energized via the controller 12, the normally open contact 142 is closed and the relay is driven.

Incidentally, in the electric motor-driven pump type power steering system configured as described above, the controller 12 has a function added to the controller 12 to cut off the power supply to the sub-fan 15 during sudden steering at a vehicle speed of IQ km/h or less. ing. That is, when the vehicle speed is determined to be 10 km/h or less based on the signal via the vehicle speed sensor 2, the vehicle speed is determined to be 250 km/h or less based on the signal via the steering sensor l.
When sudden steering of deg/sec or more is detected, the coil 141 of the relay 141 is deenergized, its normally open contact 142 is forcibly opened, and the sub fan 15
The supply of electricity to is now blocked. Detection of sudden steering in the controller 12 is performed based on the period of a pulse-like electric signal via the steering sensor 1, and blocking of power supply to the sub-fan 15 is performed when the steering state is 23 de g / s e It is designed to be restored when it becomes below c.

Therefore, when driving at low speeds of 10 km/h or less, 2
When the electric motor 42 is driven at maximum rotation due to sudden steering of 50 deg/sec or more, in other words, when the electric motor 42 is driven with a large amount of power, power is not supplied to the sub-fan 15. but its steering state is 23 d
Since it is temporarily and forcibly cut until it becomes less than e g / s e c, it does not cause an increase in the total power consumption, suppresses the drop in battery voltage, and reduces the maximum output from the oil pump 41. The discharge oil flow rate can be maintained, and sufficient steering assist force can be obtained even during sudden steering. Further, by reducing the total power consumption during such sudden steering, there is an advantage that the alternator can be made smaller.

In this embodiment, the power supply to the sub-fan 15 is cut off during sudden steering during low-speed driving, but the load for which the power supply is forcibly cut off is not limited to the sub-fan. Needless to say. For example, such loads include various in-vehicle loads such as air conditioner fans, engine cooling fans, defogger, indoor heaters, radios, stereos, cigarette lighters, rear wipers, and fog lights. By selectively blocking the light, the blocking effect can be enhanced. However, it goes without saying that care must be taken to ensure that power is continuously supplied to safety devices and the like that may interfere with driving, even during sudden steering. In addition, in this example, 250d, eg/
sec or more was determined to be a sudden steering, but this value is just a guideline, and it goes without saying that you may freely change the set value. Also, the judgment of low speed driving is lOkm.
/h or less.

〔Effect of the invention〕

As explained above, according to the power steering device according to the present invention, sudden steering in a vehicle is detected, and along with the detection of this sudden steering, at least the on-vehicle load other than the electric motor, which consumes a large amount of power, is Since the power supply is cut off, the total amount of power consumption is reduced during sudden steering, suppressing the drop in battery voltage, and ensuring sufficient steering assistance power even during sudden steering. You will be able to do this.

[Brief explanation of the drawing]

The figure is a system configuration diagram of an electric motor-driven pump type power steering system showing an embodiment of the power steering device according to the present invention. DESCRIPTION OF SYMBOLS 1... Steering sensor, 2... Vehicle speed sensor, 4... Electric motor drive pump, 41... Oil pump, 42...
...Electric motor, 12...Controller, 14...
Relay, 142... Normally open contact, 15... Sub fan.

Claims (1)

[Claims] A power steering device that performs power steering of a vehicle using an electric motor includes a sudden steering detection means for detecting sudden steering in the vehicle, and at least one other than the electric motor when the sudden steering detection means detects sudden steering. A power steering device comprising power supply cutoff means for cutting off power supply to an on-vehicle load that consumes a large amount of power.