JPS6047763A - Power steering device - Google Patents

Abstract

PURPOSE:To enable correlation between speed and steering force to be freely selected as an operator desires by enabling the mode of steering force to be selected in accordance with car speed. CONSTITUTION:The tank port 2 of a control valve V is connected to the in-port 17 of a pressure control valve S, and a control circuit L controls the pressure control valve S. A comparing solenoid 24 can reduce the opening area of a variable orifice in accordance with an electric current from the control circuit L. The changeover switch 28 of the control circuit L is provided in the driver seat, enabling a driver to operate it desirably, and permitting changeover in several stages from an off condition to mode1-moden conditions. This switching in modes causes a gain circuit G to operate, to adjust the degree of amplification of a first amplifier A1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device that changes steering force depending on vehicle speed.

(Conventional Device) Power steering devices known so far always maintain a constant correlation between vehicle speed and steering force, and cannot convert their modes. In other words, when the speed is determined, the steering force is also determined accordingly, and the driver cannot arbitrarily select the relative relationship between the speed and the steering force.

For this reason, the conventional device described above has the disadvantage that it is not possible to control the steering condition according to the preference of the cart wheeler.

(Objective of the Present Invention) The present invention provides a power steering device in which the relative relationship between speed and steering force can be arbitrarily selected according to the driver's preference.

(Embodiment of the present invention) The steering device shown in FIG. 1 has a control valve V, a pressure control valve S, and an electric control circuit for controlling the pressure control valve S as main elements.

In other words, the control valve V has a spool hole 4 formed in a main body 3 in which a pump port 1 and a tank port 2 are formed, and a spool 5 is slidably provided in the spool hole 4.

The spool 5 constructed in this way has both ends connected to the reaction force chambers 6 and 7.
The spring 8 is placed in the reaction chamber 6.7.
．． 9 is provided, and normally, due to the action of this spring 8.9,
The spool 5 is held in the neutral position shown.

The spool 5 is formed with annular grooves 1o and 11, and an annular recess 1 is formed on the inner peripheral surface of the spool hole 4.
2.13 is formed.

In the control valve v thus constructed, the annular grooves 1o, 11 of the spool 5 are different from the annular recesses 12, 13 of the spool hole 4 when the spool 5 is in the illustrated neutral position. In this neutral position, a slight gap is created between the annular groove 10, the annular recess 13, and the annular groove 11, so that the pump port 1 and the pump ports 1 and 2 communicate with each other through this gap. I have to.

When the spool 5 is switched from the neutral position to the left or right, the oil discharged from the pump P is supplied to one chamber of the actuator a, and the return oil from the other chamber of the actuator a is supplied. It is designed to flow out from tank port 2.

The control valve (2) is a known one used in rack-and-pinion type power steering, and the spool 5 is switched in the following manner.

In other words, input rotation from the handle causes the pinion wheel 14
transmitted to. As a result, the yoke 15 connected to the pinion 61114 swings, and the drive lever 1B moves left and right along with this drive.

Since the drive lever 1G is connected to the spool 5, the spool 5 is switched as the drive lever 16 reciprocates.

Tank port 2 of control valve V in this way
is in communication with the import 17 of the pressure control valve S, and the configuration of this pressure control valve S is as follows.

That is, this pressure control valve S has the inboard 17 formed in its main body 18, and an output port 19 that communicates with the reaction chamber 6.7 of the control valve (2).
and a return port 20 communicating with the tank T.

Furthermore, this pressure +ljJ control valve S has poppet 2.
1 is installed internally, and a control hole 22 is formed at a position 1δ opposite to this pope, yl-21.

The pope, ) 21 is normally held at the position shown in the figure by the action of the compression spring 23, but when the proportional solenoid 24 is energized, it moves against the spring 23. However, the amount of movement is the proportional solenoid 2
It is proportional to the amount of current applied to 4.

The pressure control valve S constructed in this manner is the above-mentioned imported l-
17 and the output port 18 are always in communication, but the return port 20 is configured to communicate with the inboard 17 and the output port 19 via the control hole 22.

Therefore, when current is applied to the proportional solenoid 24, the poppet 21 moves against the spring 23. Then, according to the amount of movement of this poppet 21, the flilJ hole 22
The amount of thrust of the tip of the poppet 21 will differ,
The larger the amount of intrusion, the smaller the opening area of this M hole 22. In other words, the poppet 21 and the control hole 22 together constitute a variable orifice.

Therefore, when the poppet 21 is in the state shown at 12, the control hole 22 is fully opened. When the control hole 22 is fully open, the oil flowing from the inboard 17 returns to the tank T via the control hole 22 and the return port 20, and the pressure in the reaction chamber 6.7 also becomes tank pressure.

In this way, when the reaction force chamber 6.7 reaches the tank pressure, only the spring force of the spring 8.9 acts on both ends of the spool 5.

When only the spring force of the spring 8.9 is acting on both ends of the spool 5, the spool moves with a force that resists the spring.

Then, the proportional solenoid 24 is energized, and the poppet 21
When the control hole 22 is moved against the spring 23, the opening area of the control hole 22 becomes smaller. Therefore, a differential pressure is generated before and after the control hole 22, and the pre-pressure flows into the reaction chamber 6.7 via the output port 18.

When pressure flows into the reaction chamber 6.7, this pressure acts as a resistance to the movement of the spool 5. Therefore, the steering reaction force increases by the pressure within the reaction force chamber 6.7.

When the opening area of the variable orifice constituted by the poppet 21 and the control hole 22 becomes the minimum, the reaction force chamber 6.7
The internal pressure also reaches its maximum. When the pressure in the reaction chamber 6.7 reaches a maximum in this way, the spool 5 is locked from both sides, and the spool 5 does not move even when the handle is turned, but maintains the neutral position shown in the figure. Therefore, the power assist is stopped and the manual steering mode yn1 is established.

In the proportional solenoid 24 configured as described above, the opening area of the variable orifice is determined according to the current from the control circuit, and the configuration of the control circuit is as follows.

That is, a vehicle speed sensor 26 is connected to the crankshaft or drive shaft of the engine 25, and this vehicle speed sensor 26 is also connected to the first amplifier A1 via a rectifier 27. This first amplifier A connected to the vehicle speed sensor 26
1 is connected to a gain circuit G that operates when the changeover switch 28 is turned on and off. And this first amplifier A,
is connected to the proportional solenoid 24 via the second amplifier A2.

The changeover switch 28 for the control circuit is provided at the driver's seat so that the driver or the like can freely operate it. Moreover, this changeover switch 28 allows switching from the OFF state to modes 1 to n in several stages. By this mode switching, the gain circuit G is operated to adjust the degree of amplification of the first amplifier A1.

However, when the Mihara changeover switch 28 is turned off, the gain circuit G does not operate, so even if the vehicle speed signal is input to the first amplifier A1, the proportional solenoid 24 is not excited.

Therefore, in this state, the proportional solenoid 24 remains de-energized regardless of the vehicle speed, so it is always in a full power state as shown by curve v0 in FIG.

Then, set the Mihara selector switch 28 to, for example, mode 1.
When the state is switched to mode 1, the gain circuit G operates accordingly and adjusts the degree of amplification of the 17th amplifier A to correspond to mode 1. Also, set the selector switch 28 to mode 2.
If the mode is switched to mode 2, the first amplifier A1 exhibits the amplification function corresponding to mode 2.

Therefore, the relative relationship between the steering force and the actuator output can be adjusted according to each mode, as shown in FIG. 3. For example, in the case of mode 1, the steering force changes in stages of V and -Vn depending on the vehicle speed. In addition, in the case of mode 2, it changes from 1' to Vn'.

(Thursday R: light configuration) The configuration of this invention is that both ends of the spool provided in the control valve face the reaction force chamber, and the pressure in the reaction force chamber is controlled by a pressure control valve controlled by a proportional solenoid. On the other hand, in a power steering device configured to adjust the energization amount of the proportional solenoid according to the vehicle speed signal and obtain a steering force according to the vehicle speed, the relative relationship between the vehicle speed signal and the energization amount to the proportional solenoid can be arbitrarily switched. n
l) It is characterized in that it is equipped with an electrical control circuit for controlling the steering force, allowing the driver etc. to freely select the mode of the steering force.

(Effects of the Present Invention) Since the present invention is configured as described by Mihara, the driver etc. can select the steering force according to his/her preference.

Furthermore, as a matter of course, the steering force can be adjusted depending on the driver's driving skills, so the steering wheel can be operated in accordance with the driver's driving skills, improving safety.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a circuit diagram showing a control valve and a specific sectional view of the control valve, FIG. 2 is a block diagram of a circuit including the control circuit, and FIG. Figure 3 is a graph showing the relationship between the steering force and the output of the actuator.V... Core 1-roll pulp, S
-...Pressure control pulp, L...control circuit, 5.6.1
Opposite chamber, 24 lives...proportional solenoid. Representative Patent Attorney Yoshiyuki Shizu

Claims (1)

[Claims] Both ends of the spool provided in the control pulp face the reaction force chamber, and the pressure in the reaction force chamber is controlled by a pressure control valve controlled by a proportional solenoid.
In the power steering device 'δ, which adjusts the amount of electricity supplied to the proportional solenoid according to the vehicle speed signal and obtains a steering force according to the vehicle speed, the relative relationship between the vehicle speed signal and the amount of electricity applied to the proportional solenoid is arbitrarily switched and controlled. This power steering device is equipped with an electrical control circuit that allows the driver to freely select one mode of steering force.