JPS59195468A - Power steering device - Google Patents

Abstract

PURPOSE:To adjust a steering characteristic right according to the fondness of a driver, by compensating the power assist force varied with a car speed with a technique of manual adjustment. CONSTITUTION:A first rheostat 39 is connected to an amplifier 35, which is connected to a car speed sensor 27, via an FV converter 34. And, a second rheostat 40 is connected to the coupling wiring between a steering sensor 28 and an operating amplifier 36 whereby a manual adjusting device 30 is formed up through both rheostats 39 and 40. On the basis of output signals out of the car speed sensor 27 and the steering sensor 28, a transistor 38 is controlled for drive motion via the operating amplifier 36 and a volt-ampere converter 37. With control of this transistor 38, the amount of continuous rating current to the coil of a flow control valve is controlled. Also with the manual adjusting device 30 operated in a proper manner, each output signal out of both sensors 27 and 28 is compensated whereby the amount of continuous rating current to a coil 25 is adjusted so as to become the power assist force that corresponds to the fondness of a driver.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a power steering device.

(Prior art) As described in Utility Model Application Publication No. 1/1/63/
In vehicle speed-sensitive power steering devices, the amount of pressure oil supplied to the power cylinder is reduced in response to an increase in vehicle speed, reducing power assist.The vehicle speed-sensitive characteristics can be manually adjusted, allowing the driver to adjust the steering output characteristics as desired. However, with such vehicle speed-sensitive types, the amount of pressurized oil supplied decreases as the vehicle speed increases.
When the steering speed is increased, there is a delay in the supply of this pressure oil, resulting in high steering resistance and difficulty in turning the steering wheel.

Japanese Unexamined Patent Publication No. 57-6-07/1987 describes a system in which the amount of pressure oil supplied to a power steering device is controlled by vehicle speed, steering speed, and lateral acceleration. In this case, the problem caused by the delay in the supply of pressure oil is solved to a certain extent, but simply changing the amount of pressure oil supply based on the steering speed causes the following problems. In other words, there are various types of drivers, such as those who prefer a large power assist force and those who prefer a small power assist force, but if the pressure oil supply amount is increased at a predetermined ratio according to the steering speed, it will be possible to increase the pressure when the steering speed is high. Those who prefer a large power assist force will feel that the steering wheel is heavy, while those who prefer a small power assist force will feel that the steering wheel is light, which will have a negative impact on drivability, such as making it difficult to turn the steering wheel.

(Object of the Invention) In view of the above, the present invention corrects the amount of pressure oil supplied to the power cylinder, that is, the power assist force, to decrease as the t-speed increases, and to increase the amount as the steering speed increases. In addition, both of these correction amounts can be changed by manual adjustment, and the manual adjustment provides steering characteristics that match the driver's preference.

(Structure of the Invention) The power steering device according to the present invention includes: ■ A power cylinder that assists the steering force; ■ An oil pump that supplies pressure oil to the power cylinder; ■ A flow control means that controls the amount of pressure oil supplied; ■ Traveling of the vehicle. A driving state sensor that detects the state ■ A steering sensor that detects the steering speed of the steering wheel ■ A controller that receives signals from the traveling state sensor and the steering sensor and issues a control signal to the flow rate control means ■ Changes the control speed of the controller Equipped with manual adjustment means, the controller changes the signal from the driving condition sensor to the first signal processing characteristic, that is, the signal processing characteristic that corrects the pressure oil supply amount in the direction of decreasing in response to the transition to high-speed driving condition. and means for processing the signal from the steering sensor according to a second signal processing characteristic, that is, a signal processing characteristic that corrects the pressure oil supply 11 in the direction of increasing the pressure oil supply 11 as the steering speed increases. and sends a control signal to the flow control means based on the signal processing, and the manual adjustment means changes both the first signal processing characteristic and the second signal processing characteristic.

(Example) In the power steering device 1 shown in FIG. 7, 2 is a steering wheel, 6 is a left and right wheel that constitutes the front wheels of a car, and 4 is a steering wheel that changes the wheels 3 and 6 in the left and right directions according to the rotational steering of the steering wheel 2. This is the steering linkage that directs the vehicle.

In this steering linkage 4, 5 is a steering shaft whose upper end is connected to the steering wheel 2, 6 is an intermediate shaft, and 7 is a lower shaft that is connected to a lower shaft.
Rack 10 of pinion 8 at the lower end of shaft 9
Both ends of the rack lift 9 are connected via tie rods 11 to knuckle arms 12 that support cars 1l-1i.

1. A power cylinder 16 that assists the steering force of the steering wheel 2 is attached to the rack shaft 9.

The power cylinder 1 is divided into a first chamber 15 and a second chamber 16 by a piston 14 fixed to the Ranokushi 4/F 1-9. The first chamber 15 and the second chamber 16 communicate with a gear control valve 17 which is connected to the lower shaft 7 at holes 18 and 19.

A gear control valve 1; is a pressure oil supply path 2 for an oil pump 21 driven by an engine 20.
2, and in response to the rotation of the steering link 2, pressurized oil is selectively supplied to the first chamber 15 and the second chamber 16 of the power cylinder 16. Further, a return passage 2 extends from the gear control knob 17.

-11 The pressure supply path 22 has a flow 't8 for controlling the amount of pressure oil supplied from the oil pump 21 to the power cylinder 13:
A control means 24 is also provided. This flow rate control means 24
is of an electromagnetic type, and the spool 26 is moved forward and backward as the coil 25 is energized, and the amount of pressurized oil supplied decreases as the amount of energization to the coil 25 increases. The coil 25 is energized by the controller 29 in response to signals from a running state sensor 27 that detects the vehicle running state (vehicle speed) and a steering sensor 28 that detects the steering speed of the steering wheel 2 attached to the lower shaft 7. It's about to be controlled. Further, a changeover switch 61 constituting the manual adjustment means 6o is connected to the controller 29,
This allows the control mode of the controller 29 to be switched between 11 (heavy) and S (soft).

In FIG. 1, the filter 2 is a regulating valve that drains a portion of the pressure oil according to the pressure difference between the upstream side and the downstream side of the flow rate control means 24. Also, 3ro is 8tteri.

The specific structure of the controller 29 and manual adjustment means 60 is shown in FIG. That is, in the same figure, 64 is a running shape jj-f.

Pulse signal from sensor (for example, vehicle speed sensor) 27 1. .

An F converter converts the signal into a voltage, filter 5 is an amplifier that amplifies the output voltage from the F'V converter 64, and filter 6 is an amplifier that amplifies the voltage output from the driving condition sensor 27 side and the steering sensor 28 side. The operational amplifier 7 is a voltage-current converter that converts the output voltage of the operational amplifier 66 into a current and transmits it to the transistor 8. The coil 25 of the flow control means 24 is connected to the collector side of the transistor 68. A first variable resistor 69 is also connected to the amplifier 65,
In addition, a second
A variable resistor 40 is provided, and both of these variable resistors 39
．． 40 constitutes a manual adjustment means 60. Both variable resistor filters 9 and 40 are interlocked, and in this example,
When the changeover switch 61 is switched from II to 5, the first
The variable resistor 39 is connected from the high resistance side to the low resistance side, and also from the second resistance side to the low resistance side.
The variable resistor 4o switches from the low resistance side to the high resistance side.

-1- In the circuit configuration described above, from the running state sensor 27 to the F
■Converter 64. The voltage input to the operational amplifier 66 via the amplifier filter 5 is eo, and the voltage input from the steering sensor 28 to the operational amplifier 6 is
Let e be the voltage input to the operational amplifier 6, and let e be the output voltage of the operational amplifier 3, then e, = K (eo-%).

Note that I( is a constant.The current i flowing through the coil 25 is proportional to the output voltage e1 of the operational amplifier 36, and the larger the current i, the higher the current i ?l1lJ The spool 26 in the control means 24 moves upward in FIG. 2 becomes large, and the pressure oil supply amount Q decreases.

Therefore, "1 voltage e. The higher the vehicle speed is, the higher the output voltage e1 of the operational amplifier 66 becomes, the more electricity is applied to the coil 25, and the pressure oil supply iQ decreases. On the other hand, the higher the voltage % is, that is, the higher the steering speed i is, the smaller the output voltage e1 of the operational amplifier 6 becomes, and the amount of current applied to the coil 25 decreases, and the pressure oil supply meter 9 increases.

Here, select switch RO 1 or H of manual adjustment means 6o.
, and when the steering speed θ is constant, as the vehicle speed V increases, the voltage e0 (increases according to the characteristics shown in FIG. 3, and becomes saturated when it reaches the battery voltage. Therefore, For example, when the steering speed θ is low and tj = 61, as the vehicle speed \l increases, the pressure oil supply amount Q slightly reaches the saturation voltage (bacterial voltage) as shown by the solid line in Fig. At this point, the pressure oil supply ff1Q is at its lowest level.In other words, the signal from the running state sensor 27 is processed in accordance with the processing characteristics indicated by the solid line θ1 in FIG.

On the other hand, looking at the relationship between the steering speed i and the pressure oil supply amount Q, when the vehicle speed V is constant, as the steering speed i increases, the pressure 1t-b supply phrase Q becomes linear as shown by the solid line in FIG. increases to In other words, the signal from the steering sensor 28 is processed according to the second signal processing characteristic shown by the solid line in FIG.

However, manual adjustment means 0 switching switch.

When the switch 31 is switched to S, the first variable resistor 69 switches from the high resistance side to the low resistance side, so that the input voltage e to the operational amplifier 6. becomes lower and the pressure supply amount Q increases, and the signal processing characteristics shift to the right as shown by the chain line i1 in FIG. Since the input voltage ey to the operational amplifier 66 becomes high (and the pressure oil supply (ffi Q) increases. In other words, the processing characteristics are as shown by the chain line in FIG. (The slope is larger than that of a solid line.

Therefore, the selector switch 61 of the manual adjustment means 60 is set to E.
When set to 1, as shown in FIG.

Comparing the increases H and B when Chiro 1 is set to S,
5th than when set to S or l].
Corresponding to the slope of the characteristic shown in the figure, it becomes thicker (becomes thicker).Here, if we look at the relationship between the steering torque T of the steering wheel and the steering speed i when the vehicle speed V=a, the relationship between the steering torque T and the steering speed i is as shown in FIG. 1-1
When set to S, the amount of increase in the pressure oil supply amount Q due to an increase in the steering speed i is small, so the steering torque T of the steering wheel tends to increase as the steering speed θ increases. At this time, the amount of increase in the pressure oil supply amount Q is large, so the steering torque T of the steering wheel remains constant.

As described above, in the case of the example, the first signal processing characteristic and the second
The signal processing characteristics are changed by switching from tl to S by the manual adjustment means 30, so that as the pressure oil supply fflQ increases and the power assist force becomes larger, the increase correction amount of the pressure oil supply (iQ) increases. Therefore, for example, if the changeover switch 1 is set to II, the power assist force will be small even when the vehicle speed is relatively low, and the amount of increase in the power assist force as the steering speed i increases will also be small. On the other hand, when the steering torque is set to S, the vehicle speed becomes higher than when set to H (the power assist force starts to decrease and the steering speed i increases). As a result, the amount of increase in power assist force increases, resulting in driving with a low steering torque as a whole.

In addition, in the embodiment described in -, the first . The second signal processing characteristic may be changed in two steps, three steps, or without steps.

In addition, in the embodiment described in section 1, the signal from the running state sensor 27 and the signal from the steering sensor 28 are combined to control the seven flow rate control means 24, but in response to the signal from the running state sensor 27, A first flow control means that responds to the signal from the steering sensor 28 and a second flow control means that responds to the signal from the steering sensor 28 are connected in parallel to the pressure oil supply path 22, and each flow control means is individually controlled by the vehicle speed signal and the steering speed signal. You can do it like this. In this case, since the second flow rate control means is directly controlled by the signal from the steering sensor 28, the pressure oil supply amount is immediately increased in response to an increase in the steering speed, improving responsiveness and steering control. Kara (Naru)

Further, as the driving state sensor, an engine rotation sensor, a transmission gear position sensor, or the like may be used in addition to the vehicle speed sensor of the above embodiment.

(Effects of the Invention) The present invention corrects the pressure oil supply amount to decrease as the vehicle speed increases, and to increase the amount as the steering speed increases, by manually adjusting the correct amount of oil on both sides. Therefore, the power steering characteristics can be set according to the driver's preference.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 7 is an overall configuration diagram of a power steering device, FIG. 2 is a control circuit diagram, and FIG.
The figure shows vehicle speed V and input voltage e to the operational amplifier. FIG. 7 is a graph showing the processing characteristics of the first signal 14,
Figure 5 is! FIG. 4, a graph showing the signal processing characteristics, is a graph showing the relationship between the steering speed δ and the steering torque T.

Claims (2)

[Claims] (1) A power cylinder that assists the steering force, an oil pump that supplies pressure oil to the power cylinder, a flow control means that controls the amount of pressure oil supplied from the oil pump to the power cylinder, and a vehicle. A driving state sensor detects the driving state of the vehicle, and a steering sensor detects the steering speed of the steering wheel.The signals from the driving state sensor are processed according to a first signal processing characteristic, and the signals from the driving state sensor are processed according to a first signal processing characteristic, and the signals from the driving state sensor are processed according to a first signal processing characteristic. A control signal is sent to the flow control means to reduce the pressure oil supply amount, process the signal from the steering sensor according to the second signal processing characteristic, and increase the pressure oil supply amount according to the increase in steering speed. A power steering device comprising: a controller that emits a signal; and manual adjustment means that changes both first and second signal processing characteristics of the controller. (2) The controller is configured to change the first/second signal processing characteristics so that the amount of incremental correction increases as the power assist force becomes relatively high, based on the belief of the manual adjustment means. A power steering device according to claim 1.