JPH0211473A - Power steering used for automobile - Google Patents

Abstract

PURPOSE:To remedy a delay in the response of an automobile behavior to handle control by a method wherein based on a steering angle, opening and closing of a plurality of injection valves are controlled, and a delay-in-response correction pressure oil is selectively injected in a pair of the reaction force chambers of a control valve. CONSTITUTION:A power steering 10 is formed with a steering wheel 11, a steering shaft 12, and a power device connected to a hydraulic circuit. The power device is formed with a power cylinder 13, a control valve 14 having a pair of reaction force chambers 50 and 51, and an oil pump 15. In this case, delay-in-response correction oil pressure passages 22 and 23 are connected to the reaction force chambers 50 and 51, respectively, and electric pressure oil injection valves 24 and 25 are disposed to the passages 22 and 23, respectively. Opening and closing of the electric pressure oil injection valves 24 and 25 are controlled by a control unit 26 based on a signal from a steering angle sensor 28. This constitution causes selective injection of delay-in-response correction pressure oil to the reaction force chambers 50 and 51.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to power steering used in automobiles, and in particular to power steering that improves responsiveness.

BACKGROUND TECHNOLOGY In power steering used in automobiles, a steering force sensor is built into the steering wheel in order to reduce the response delay of the automobile's behavior to steering wheel operations and improve steering stability. Some systems use sensors to detect steering signals and use the detected steering signals to correct the delay in control valve operation and drive the booster, but in this case, the steering wheel has become structurally complex.

Objectives and Problems of the Invention The objects and problems of the present invention are to enable accurate detection of steering signals using simple means, improve response delay in vehicle behavior to steering wheel operations, improve steering stability, and achieve safer driving. The purpose of this invention is to provide power steering used in automobiles, which enables automobiles to perform the following functions.

Summary of the invention in terms of structure related to the object/problem: Contents of the claimed invention In relation to the above-mentioned object/problem, the power steering system of the present invention used in an automobile includes an oil pump and a pair of reaction force chambers. A hydraulic circuit includes a control valve operated by the steering wheel, and a power cylinder, and a response delay compensation hydraulic passage connects the reaction force chamber to the discharge side of the oil pump, and an electric A pressure oil injection valve is disposed in the response delay compensation hydraulic passage, and the steering wheel is configured to have a steering performance ratio less than or equal to that of a normal steering wheel, and a steering angle sensor connects the steering wheel. a control unit is disposed on the steering shaft and is electrically connected to the steering angle sensor and controls the current flowing to the electric oil filler valve in response to a signal from the steering angle sensor; The pressure oil injection valve is selectively opened and closed to selectively inject response delay correction pressure oil into the reaction force chamber, and by reducing the weight of the steering wheel, the steering wheel The steering angle sensor substantially detects the operating force applied to the steering angle sensor, and the electric pressure oil injection valve opens and closes in response to the signal detected by the steering force sensor to supply the response delay correction pressure oil. It is selectively injected into the reaction force chamber to reduce the delay in the response of the power cylinder to steering wheel operations, thereby improving the response delay in the behavior of the automobile.

DESCRIPTION OF EMBODIMENTS Preferred embodiments of the power steering system for use in automobiles according to the present invention will be described below with reference to the drawings.

Figures 1 and 2 show a specific example 1 of the power steering used in the automobile of the present invention, which is applied to a medium-sized truck.
0 is shown schematically.

This power steering 10 is composed of a steering wheel 1), a steering shaft 12, a power unit connected to a hydraulic circuit, and a link mechanism, and is swingable at both ends of the front axle (not shown) of the truck. A pair of front wheel shafts (not shown) connected to the front wheel shaft are steered, and a pair of front wheels (not shown) rotatably supported by the front wheel shaft are capable of power steering and manual steering.

The power plant includes a power cylinder 13, a control valve 14 with a pair of reaction chambers 50, 51, an oil pump 15, a flow control valve 16, and an oil reservoir 17 for supply and return to a hydraulic circuit. The side hydraulic passages 29 and 30 connect the two reaction force chambers 50 and 51, and the reaction force adjustment passage 18 connects the pair of reaction force chambers 50 and 51 with each other.
A reaction force adjustment valve 19 is arranged in the reaction force adjustment passage 18,
A restriction 20 is upstream of the flow control valve 16 and the supply hydraulic passage 29 connects the oil pump 15 to the control valve 14.
The response delay correction hydraulic passage 21, 22, 23 is arranged in the supply hydraulic passage 2 on the upstream side of the throttle 20.
9 and a pair of reaction chambers 50 of its control valve 14.
．． 51, a pair of electric pressure oil injection valves 24, 25,
A pair of control valves 14) I chamber 50
51, and the control unit 26 is electrically connected to the vehicle speed sensor 27 and the steering angle sensor 28, and the control unit 26 is electrically connected to the vehicle speed sensor 27 and the steering angle sensor 28. The electric current flowing through the electric actuator 83 of the reaction force regulating valve 19 is controlled according to the signal from the steering angle sensor 28, and the electric pressure oil injection valve 24, 25 is controlled according to the signal from the steering angle sensor 28.
Control the current flowing to the electric pressure oil injection valve 24゜25
It opens and closes and is configured to inject response delay correction pressure oil whose pressure is given by the throttle 20 as a function of the engine speed into the reaction force chambers 50 and 51, and in particular, the pair of front wheels can be manually steered. The steering shaft 12 is connected to the piston 44 of the power cylinder 13 so as to
It is constructed as an integral type by connecting with a ball and screw.

The link mechanism includes a pitman arm (not shown) fixed to the sector shaft 47 of the power cylinder 13, a drag link (not shown), a knuckle arm (not shown), and a It consists of tie ronds (not shown) and a pair of tie rond arms (not shown) that connect the wheel axles to each other, and of course the knuckle arms are attached to the chassis frame (not shown) of the truck. The front wheel is rotatably connected to both ends of a front axle located at the front via a knuckle (not shown) and a king pin (not shown) to rotatably support the front wheel. ing.

The steering wheel 1) is made to have a coefficient of inertia less than 2 that of a conventional steering wheel. In other words, if the inertia factor is large, there will be a large time delay before the steering wheel 1) starts to rotate due to the steering force, so the steering wheel 1)
) was manufactured with an inertia factor of 5m-kg-5''.

Ideally, however, the steering force applied to the steering wheel 1) would be directly detected.
Since it would be extremely troublesome and structurally complex to produce a means for detecting the steering force with high precision, the present invention detects the steering force by a conventional means. There is an intention behind this, and we are trying to detect it simply like that.

The steering shaft 12 connects the steering wheel 1) and, as will be explained later, the power cylinder 13 is ball screw coupled to a piston 44 and connects the steering wheel 1).
) is capable of transmitting the steering force applied to the piston 44 thereof, and the control valve 14 is as follows:
It is connected to the spool shaft 34 to enable the movement of the steering wheel to be transmitted to the spool 52 of the control valve 14.

The power cylinder 13 incorporates the control valve 14 and an oil cylinder connected to the cylinder ports 54, 55, 56 of the control valve 14.
A cylinder body 40 having a cylinder bore 41 communicating with ports 45, 46;
A pair of cylinder chambers 4 are fitted in a reciprocating manner and connected to the oil port 45° 4G.
2° 43 in its cylinder bore 41, and a sector shaft 47 meshed with the piston 44 and transmitting the force and movement of the piston 44 to its pitman arm. There is. Of course, the piston 44 is ball screw coupled to the steering shaft 12, as previously described, to enable manual steering of the front pair of wheels.

Moreover, this power cylinder 13 has its cylinder chamber 4
2 oil port 45 and its control valve 1
4 cylinder ports 54. 55, and the oil port 46 of its cylinder chamber 43 and the cylinder of its control valve 14.
A communication path 33 communicating with the port 56 is provided. Of course, the communication passages 31, 32 and 33 are switched and connected by the control valve 14 to the supply and return pressure passages 29, 30, and the power cylinder 13, the control valve 14, the oil・
Pump 15, flow control valve 16, oil reservoir 17 and its supply and return pressure passages 2 connecting the relief valve to the hydraulic circuit.
It is part of 9.30.

In a power cylinder 13 so configured, the force and movement of its piston 44 is transmitted to its sector shaft 4.
7. transmitted to the front wheel via the pitman arm, drag, link and knuckle arm, thus
Its power cylinder 13 steers its front wheels.

The control valve 14 is configured as a hydraulic reaction type spool valve, is incorporated into the cylinder body 40 of the power cylinder 13, and is connected to an input shaft (not shown) connected to the steering shaft 12. The spool 52 is connected to a fixed spool shaft 34, and the valve is switched by the steering wheel 1) fixed to the steering shaft 12, and
In the hydraulic circuit, the supply side hydraulic passage 29 connecting the oil pump 15 and the oil reservoir 17 to the power cylinder 13, the return pressure passage 30, and the communication passages 31, 32, 33 are arranged, That oil
It controls the direction of the pressure oil discharged from the pump 15 and whose flow rate is controlled by the flow control valve 16, and supplies it to the power cylinder 13, and also controls the direction of the pressure oil worked by the power cylinder 13. , the oil
Its oil reservoir 17 is the suction side of the pump 15
Return the pressure oil to.

The control valve 14 includes a valve body 48 having a valve bore 49, a valve body 48 disposed in the valve bore 49 so as to be able to reciprocate, and a pair of reaction chambers 50, 51 at both ends of the valve bore 49. It is composed of a spool 52 forming a spool 52.

The valve body 48 is connected to the power cylinder 13
The pump boat 53, cylinder boats 54, 55, 56, and tank boat 57 are installed in the cylinder body 40 of the pump, and are opened to the valve bore 49 at predetermined positions.

The pump boat 53 and tank boat 57 are
Openings in the inner peripheral surface of the valve bore 49 are formed into ring grooves 58 and 59, respectively.

The valve body 48 also has a reaction chamber 50.5.
1, and includes a pair of reaction boats 60, 61 and a pair of correction hydraulic boats 6263, which are opened in the valve body 48.

The spool 52 has bores 64.6 opened on both end faces.
5, respectively, and the volumes of the reaction force chambers 50 and 51 are increased.

In addition, when the spool 52 is placed in the neutral position, lands 66 and 67 are formed on the outer peripheral surface of both ends located outside the ring grooves 58 and 59, and between the lands 66 and 67, , the lands 68., facing the ring grooves 58.59. (39 is formed on the outer peripheral surface.

Of course, with the spool 52 placed in the neutral position,
A spool groove is formed on the outer peripheral surface of the spool 52 between the lands 66, 67 and 68, 69 so as to be located on the cylinder boats 54, 55, and 56. 0,71.72 are formed and the spool grooves 70,71,72 move the pump boat 53 into the cylinder as the spool 52 is slid back and forth into the valve bore 49.
The cylinder boats 54, 55, 56 can be switched and connected to the tank boats 57.

The spool 52 also has communication ports 73.7 that communicate with the corresponding bores 64, 65 and spool grooves 71,72.
It is equipped with 4.

The communication boat 73, 74 switches and connects the reaction chambers 50, 51 to the pump boat 53 and tank boat 57 as the spool 52 is slid back and forth into the valve bore 49. .

Further, the control valve 14 controls the power supply of the pressure oil discharged from the oil pump 15 and whose flow rate is adjusted by the flow control valve 16.
In order to supply the cylinder chamber 42,43 of the cylinder 13, the pump boat 53 has its supply hydraulic passage 29
So, the lower part of the flow control valve 16
The cylinder boats 54, 55, 56 are connected to the oil boats 45, 46 of the power cylinder 13 by their communication passages 31, 32, 33, and the tank boats 57 are connected to their return pressure passages. 30 respectively connected to its oil reservoir 17.

The oil pump 15 is driven by a diesel engine (not shown) mounted on the truck and is connected to a pump port 53 of the control valve 14 to supply pressurized oil to the power cylinder 13. It is arranged in the supply side hydraulic passage 29 of the hydraulic circuit connecting the oil reservoir 17, sucks up the oil in the oil reservoir 17, pressurizes it, and discharges pressurized oil approximately proportional to the rotation speed of the diesel engine. I'm trying to get the quantity. Of course, the oil pump 15 can be used with the existing power
Since it is manufactured to have a similar structure to the oil pump used for steering, the explanation thereof will be omitted.

The flow control valve 16 is located in the hydraulic circuit in a supply hydraulic passage 29 connecting the control valve 14 to the oil pump 15 and oil reservoir 17, and
It is connected to its return pressure passage 30 by a valve bypass 79, in particular because its restriction 20 is arranged in its supply hydraulic passage 29 between its oil pump 15 and its control valve 14. The flow control valve 16 is arranged in the supply hydraulic passage 29 downstream of the restriction 20 .

The flow control valve 16 is connected to the throttle 2
The inlet arrow connected to the exit side of 0, its control
Outlet lower 7 connected to pump port 53 of valve 14
, and a return lower 8 connected to the return pressure passage 30, and an oil return control spool (not shown) disposed within the valve casing 75 so as to be able to reciprocate. The flow rate of the pressure oil sent to the inlet aro is adjusted, a predetermined flow rate is sent to the outlet lower 7, and the excess flow of the pressure oil is sent from the return lower 8 to the oil.・Reservoir 1
7 via control valve bypass 79.

Of course, the flow control valve 16 is manufactured to have a similar structure to the flow control valve used in existing power steering systems, and a detailed explanation of its structure will be omitted.

The reaction force adjustment passage 18 is connected to the control valve 1
A pair of reaction force chambers 50 and 51 of No. 4 are connected to each other.

That is, the reaction force adjustment passage 18 is connected to one reaction force chamber 50.
One end is connected to a reaction port 60 opened to the other reaction force chamber 51, and the other end is connected to a reaction port 61 opened to the other reaction force chamber 51, so that the reaction force chambers 50 and 51 are connected to each other.

Of course, piping with a predetermined inner diameter and length is used for the reaction force adjustment passage 18, but without using such piping, the valve body 48 or cylinder
Holes may be formed in the body 40.

The reaction force regulating valve 19 includes a valve body 80 having a spool chamber (not shown) and a pair of ports (81, 82) communicating with the spool chamber, and a reciprocating slide in the spool chamber. a spool (not shown) movably arranged to change a passage cross-sectional area within its spool chamber in response to its reciprocating sliding;
It is comprised of an electric actuator 83 that slides the spool back and forth within the chamber.

Thus, as the spool is slid back and forth into the spool chamber by the electric actuator 83, the flow rate of hydraulic oil flowing between the ports 81, 82 is regulated so that the control valve 14 The pressure within the reaction force chambers 50, 51 is adjusted.

Further, the pressure regulating valve 19 has been described as a spool type, but it can have any shape as long as it regulates the flow rate of the pressure oil flowing between the ports 81 and 82.
For example, it may be configured as a rotary type.

The throttle 20 is a fixed throttle, and the oil pump 15
and its flow control valve 16 in its supply hydraulic passage 29, and its oil pump 1
The pressure oil discharged from 5 and flowing into the flow control valve 16 is throttled, and the response delay compensation hydraulic passage 2
1, 22° 23, in other words, the pressure of the response delay correction pressure oil injected into the reaction chambers 50, 51 of the control valve 14 is given as a function of the engine speed,
In particular, as the engine speed increases, the pressure of the response delay correction pressure oil is increased.

The throttle 20 includes a casing 84 having a bore (not shown) therein and inlet and outlet connection ports 85, 86 formed at opposite ends of the bore. The orifice plate (not shown) is arranged to narrow the passage cross-sectional area of the bore.

The aperture 20 manufactured in this way is a function of the engine speed which is closely related to the vehicle speed, in other words, which substantially represents the vehicle speed, so-called a function of the engine function which substantially represents the vehicle speed. The pressure of the response delay correction pressure oil is simply applied to the control valve 14, and the pressure of the response delay correction pressure oil is increased even when the truck is traveling at high speed. It is possible to increase the amount of the response delay correction pressure oil injected into 51, thereby making it possible to correct the response delay.

Further, it is preferable that the diaphragm 20, which functions in this manner, be manufactured in a structure in which the amount of diaphragm can be finely adjusted manually.

The response delay correction hydraulic pressure passages 21, 22, 23 are connected to each other, the response delay correction hydraulic pressure passage 21 is connected to the supply hydraulic passage 29 on the upstream side of the throttle 20, and the response delay correction hydraulic pressure The passage 23.23 is connected to a compensation hydraulic port 1-62.63 formed in the valve body 48 of the control valve 14.

The response delay correction hydraulic passages 21, 22, 23, which become such branch oil passages, connect the upstream side of the throttle 20 of the supply side hydraulic passage 29 to the control valve 14.
The control valve 14 is connected to a pair of reaction chambers 50.51, and its throttle 20 leads response delay correction pressure oil whose pressure is a function of the engine speed into the pair of reaction chambers 50.51 of the control valve 14. Delays in the operation of the control valve 14 are avoided, and so-called power steering response delays can be corrected.

The pair of electric pressure oil injection valves 24 and 25 are electromagnetic type two-way control valves, and are respectively arranged in the corresponding response delay correction hydraulic passages 22 and 23.

In addition, the electric pressure oil injection valve 24,25 is a solenoid.
The coils 87, 88 are connected to the output circuit of the control unit 2G, and the response delay correction pressure oil, which is driven by a current controlled by the control unit 26 and whose pressure is given as a function of the engine speed, is connected to the output circuit of the control unit 2G. Control·
It is selectively injected into the reaction force chambers 50 and 51 of the valve 14 in response to steering.

The control unit 26 has an input side electrically connected to the vehicle speed sensor 27 and a steering angle sensor 28, respectively, and an output side to the electric actuator 83 of the reaction force regulating valve 19 and the electric pressure oil injection valve 24. .25 solenoid coils 87, 88, respectively, and in response to signals from those sensors 27, 28, the electric actuator 83 and solenoid coil 87
Controls the current flowing to 88°.

That is, the control unit 26 controls the current flowing through the electric actuator 83 of the reaction force regulating valve 19 in response to signals from the vehicle speed sensor 27 and the steering angle sensor 28 to move the spool into the spool chamber. The cross-sectional area of the passage in the spool chamber is changed by sliding, and a hydraulic reaction force corresponding to the vehicle speed is generated in the reaction force chambers 50 and 51, and the supply hydraulic pressure on the upstream side of the throttle 20 is changed. In the passage 29, pressure oil whose pressure is given by the engine speed by the throttle 20, that is, response delay correction pressure oil, is obtained, so the electric pressure oil is injected according to the signal from the steering angle sensor 28. The current flowing through the solenoid coil 87.88 of the valve 24.25 is controlled to selectively open its electrostatic oil injection valve 2425, thereby selectively passing through its response delay compensation hydraulic passage 22.23. Response delay correction pressure oil is selectively injected into the reaction force chambers 50 and 51 to suppress delay in operation of the control valve 14 and avoid delay in turning the power steering 10. Of course, the control unit 26 is comprised of input and output circuits, memory circuits, arithmetic circuits, control circuits, and a power supply circuit, which also shares the battery 35 of the truck.

The vehicle speed sensor 27 detects the running speed of the truck and is arranged on the output shaft of a transmission (not shown) mounted on the truck, and the steering angle sensor 28 detects the running speed of the truck. A normal rotation sensor that detects the rotation speed, rotation direction, rotation angle, etc. of the steering shaft 1.
2 around its steering shaft 12 in predetermined positions.

Next, to describe the operation of the above-mentioned power steering 10 in relation to the running state of the trunk, since the diesel engine is being operated, the oil pump 15 is driven, and the oil pump 15 is driven. The pressure oil discharged from 15 passes through the throttle 20, the flow rate is adjusted by the flow control valve 16, and flows through the supply side hydraulic passage 29 to the control valve 14.
is sent to pump port 53 of. Of course, the aperture is 20
The flow rate of the pressure oil flowing to the inlet side of the flow control valve 16 is reduced by the throttle 20, passes through the supply side hydraulic passage 29 downstream of the throttle 20, and flows from the outlet side of the throttle 20 to the inlet of the flow control valve 16. Since it will be sent to Aro, its aperture is 20
In the supply hydraulic passage 29 on the upstream side of the engine, pressure oil whose pressure is given as a function of the engine speed, so-called response delay correction pressure oil, is obtained.

At the same time, the control unit 26 inputs signals from the vehicle speed sensor 27 and the steering angle sensor 28, and controls the electric actuator 83 of the reaction force adjustment valve 19.
, and the solenoid coils 87, 88 of the electric pressure oil injection valves 24, 25, respectively, so that a hydraulic reaction force suitable for the vehicle speed and steering is obtained in the reaction force chambers 50, 51 of the control valve 14. The hydraulic fluid is in a state where it flows into the response delay correction hydraulic pressure passages 21, 22, and 23.

In such a situation, if the steering wheel is in the neutral position, the spool 52 is also in the neutral position as shown, so that the pressure oil sent to the pump port 53 is The return pressure passage 30
from the tank port 57 to the oil reservoir 17.

Therefore, the steering force when rotating the steering wheel 1) will be described first.

Now, if the trunk is running at a low speed, the control unit 26 inputs signals from the vehicle speed sensor 27 and steering angle sensor 28, calculates based on the input signals, and adjusts the reaction force adjustment valve 19. The current flowing through the electric actuator 83 of the reaction force adjustment valve 19 is determined, and the current flowing through the electric actuator 83 of the reaction force adjustment valve 19 is controlled. The spool is slid into the chamber and the cross-sectional area of the passage within the spool chamber is widened.

In such a state, when the steering wheel 1) is rotated in either direction, the spool 52 of the control valve 14 is correspondingly slid to the left or right.

Then, depending on the sliding direction of the spool 52, the pressure oil is transferred to the cylinder chamber 42.4 of the power cylinder 13.
3 and to either the reaction force chambers 50, 51 of the control valve 14.

For example, if the spool 52 is slid to the right in the figure, the pump port 53 will connect to the cylinder port 56 via the spool groove 71 of the spool 52.
, and that tank port 57 is connected to that spool 5.
The pressure oil discharged from the oil pump 15 is sent to the cylinder chamber 43 of the power cylinder 13 through the communication passage 33, and the piston 44 is
In the figure, the power cylinder 1 is slid to the right.
The pressure oil in the cylinder chamber 42 of No. 3 is returned to its oil reservoir via the communication passage 31, 32 and the return pressure passage 30.

In this way, when pressure oil is supplied, a part of the pressure oil passes through the communication boat 73 and the bore 64 to the reaction force chamber 5.
Sent to 0.

The reaction force during such steering is given by the oil pressure in the reaction force chamber 50, but as mentioned above, during low speed driving, the passage cross-sectional area of the reaction force adjustment valve 19 is widened, so that The pressure oil in the reaction force chamber 50 is controlled by the reaction force adjustment passage 18.
, and flows to the other reaction force chamber 51 without being extremely restricted by the reaction force adjustment valve 19 .

Moreover, if the spool 52 is slid in the above-mentioned direction,
The tank port 57 is connected to the spool groove 72, and the pressure oil in the reaction chamber 51 is transferred to the bore 65, the communication port 74, the spool groove 72, the tank port 57, and the return pressure passage 30. through the oil reservoir 1
It will be returned to 7.

Therefore, the pressure drop caused by the reaction force adjustment valve 19 becomes smaller, the pressure difference between the left and right reaction force chambers 50 and 51 becomes smaller, and the pressure oil in the reaction force chamber 50 is reduced by the sliding of the spool 52. In other words, when driving at low speeds, steering is performed with a small operating force.

Also, if the spool 52 in the control valve 14 is slid to the left in the figure, the pump port 57 will be in the spool groove 70 and the tank port 57 will be in the spool groove 70. 1j1), and the pressure oil discharged from the oil pump 15 is sent to the cylinder chamber 42 of the power cylinder 13 through the communication passage 31, and the piston 44 is slid to the left in the figure. The pressure oil in the cylinder chamber 43 of the power cylinder 13 is returned to the oil reservoir 17 via the communication passage 33 and the return pressure passage 30.

Contrary to the case described above, the pressure oil in the reaction force chamber 51 passes through the reaction force adjustment passage 18 and is sent to the reaction force chamber 50 without being extremely throttled by the reaction force adjustment valve 19. The pressure oil in the reaction chamber 50 is transmitted through the bore 64, the communication port 73, the spool groove 71, the tank port 57, and the return pressure passage 30.
and is returned to its oil reservoir I7.

Therefore, as in the case described above, the pressure drop caused by the reaction force adjustment valve 19 becomes smaller, the pressure difference in the left and right reaction force chambers 50, 51 becomes smaller, and the pressure oil in the reaction force chamber 51 is reduced. There is no large resistance to sliding of the spool 52, and steering is performed with a small operating force.

Further, as described above, when the truck is parked, the traveling speed is zero, so the passage cross-sectional area of the reaction force adjustment valve 19 is expanded to the maximum, and the reaction force chamber is The pressure difference between 50 and 51 becomes extremely small, and as a result, the stationary operation is performed with extremely small operating force.

Furthermore, if the truck is driven at high speed, the control unit 26 will be activated by the vehicle speed sensor 27.
A signal is inputted from the steering sensor 28 and the current flowing through the electric actuator 83 of the reaction force adjustment valve 19 is determined by calculation based on the input signal. Because it controls
In the reaction force regulating valve 19, the spool is slid into the spool chamber by the electric actuator 83, and the passage cross-section in the spool chamber is narrowed adapted to the vehicle speed in this case. .

In such a state, when the steering wheel 1) is turned to either the left or right as in the case of low-speed driving described above, the spool 52 of the control valve 14 will be turned to the left or right in response. It is slid to either side.

Then, depending on the sliding direction of the spool 52, the pressure oil is transferred to the cylinder chamber 42, 43 of the power cylinder 13.
and the piston 44 is slid,
Also, a part of the pressure oil is sent from either of the reaction force chambers 50 and 51, but since the cross-sectional area of the passage in the spool chamber of the reaction force adjustment valve 19 is narrowed, the reaction force The pressure drop caused by the regulating valve 19 becomes large, and the pressure difference between the left and right reaction force chambers 50 and 51 becomes large. There will be great resistance against it.

In this way, a relatively large operating force is required for steering during high-speed running, and running stability is improved.

Next, correction of the response delay when the steering wheel 1) is rotated will be described. Of course, this delay correction is performed simultaneously with the reaction force adjustment described above.

If the steering wheel 1) is rotated in either the left or right direction, the control unit 26 outputs a steering signal corresponding to the left or right direction in which the steering wheel 1) is rotated. is input from the steering angle sensor 28, and calculated based on the steering signal to determine the current to flow through either one of the solenoid coils 87, 88 of the electric pressure oil injection valve 24, 25, Injection valve 24.25 solenoid coil 87.
88 to open either one of the electric pressure oil injection valves 24, 25.

As such, the electric pressure oil injection valve 2 corresponds to which side the steering wheel 1) is rotated.
4.25 is opened, the response delay correction pressure oil, whose pressure is given as a function of the engine speed corresponding to the traveling speed of the truck, will increase the supply hydraulic pressure upstream of the throttle 20. It flows from the passage 29 to the response delay correction hydraulic passage 21, and is injected into either one of the reaction force chambers 50, 51 of the control pulp 14 through either of the response delay correction hydraulic passages 22, 23. .

The steering signals detected in this way
The response delay correction pressure oil input to the unit 26 and whose pressure is given by the engine speed is applied to the reaction chamber 50, 51 of the control pulp 14 in response to the steering direction of the steering wheel 1). Since it is injected into either one, the delay in the operation of the control valve 14 is suppressed, and the responsiveness of the power cylinder 13 is improved.
The delay in the actual steering angle of the front wheels relative to the steering force of the steering wheel 1) is kept small.

Figure 2 shows the vehicle speed 10 with the trunk fully loaded.
This is data on sudden steering obtained when the vehicle was traveling at 0 km/h. In other words, the delay in actual steering angle with respect to steering force is 0.10 seconds, and the delay in yaw rate is 0.2 seconds.
It was 6 seconds.

In this way, from the data in Figure 2, the steering
The steering angle sensor 28 is arranged around the steering shaft 12 of the wheel 1) to reduce its inertia factor.
In this power steering 10, which obtains a steering signal from
An effect similar to that of power steering, where the steering signal is obtained using a steering force sensor, can be obtained.

Also, if the steering wheel 1) is rotated in the opposite direction to that described above, this power steering wheel 10
is operated substantially in the opposite direction to that described above to steer its front wheels in the opposite direction to that described above, and at this time, the delay in the actual steering angle of the front wheels relative to the steering force of the steering wheel 1) is kept small. be done.

In the power steering system 10 described above, the pair of electric pressure oil injection valves 24.25 were described as being embodied as electromagnetic type two-way control valves, but the pair of electric pressure oil injection valves 24.25 It is also possible to install the control valve in one electromagnetic type 3-position 4-way control valve.

Further, in the power steering 10 described above, the throttle 20 is arranged in the supply side hydraulic passage 29 between the oil pump 15 and the flow control pulp 16, and the response delay correction hydraulic passage 21 was described as being connected to the supply hydraulic passage 29 between the oil pump 15 and the flow control valve 16; The control valve 14 and the flow control valve 1
6 may be connected to its supply side hydraulic passage 29 between the two.

Further, in the power steering 10 described above, the aperture 20 was explained as being a fixed aperture, but the aperture 20 is a variable aperture whose aperture amount can be changed by the control unit 26 according to the vehicle speed. If it is replaced by , the response delay correction in the high-speed driving range of the trunk will be further enhanced.

Further, in the power steering system 10 described above, the control valve 14 has been described as being embodied in a spool type, but the control valve 4 can also be embodied in a rotary type.

Further, in the power steering 10 described above, the power WF
Although t has been described as being embodied as an integral type, the power plant can be embodied as either a semi-integral type or a linkage type.

Advantages and Benefits of the Invention From the foregoing, it can be seen that compared to the power steering systems used in automobiles, which have already been proposed and used, in which the reaction force is hydraulically applied and the steering delay is corrected. The power steering used in the automobile of this invention includes an oil pump, a control valve having a pair of reaction force chambers and operated by a steering wheel, and a power cylinder connected to a hydraulic circuit, which reduces response delay. A compensation hydraulic passage connects the reaction chamber to the discharge side of the oil pump, an electric pressure oil injection valve is disposed in the response delay compensation hydraulic passage, and the steering wheel is configured to
The inertia factor is 1/1 that of a normal steering wheel.
2 or less, the steering angle sensor detects that steering angle.
located on the steering shaft connecting the wheels, and a control unit electrically connected to the steering angle sensor to control the current flowing to the electric oil injection valve in response to a signal from the steering angle sensor. and selectively opens and closes the electric pressure oil injection valve to selectively inject response delay correction pressure oil into the reaction force chamber. Now, by using a simple means such as a steering wheel with a low inertia factor and a steering angle sensor, the steering signal can be detected as accurately as that obtained by the steering force sensor, and based on the steering signal, the response delay correction pressure can be calculated. Oil can be injected into the reaction force chamber, thereby suppressing the delay in the operation of the control valve, and improving the responsiveness of the power cylinder, improving the response delay in the vehicle's behavior to steering wheel operations. Accordingly, the steering stability is improved, and safer driving is ensured for the automobile, making it extremely practical and useful for the automobile.

As for the relationship between the invention and the specific examples, from the specific examples of the present invention described with reference to the drawings, various design modifications will be apparent to those who have ordinary knowledge in the technical field to which this invention pertains. Further, the contents of this invention are essential to the establishment of the invention for accomplishing the task of the invention, and are derived from the technical essence of the invention which is the nature of the invention. Then, it can be easily replaced by Gfi, which is objectively recognized as having it internally.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a specific example of power steering used in an automobile of the present invention applied to a medium-sized truck, and FIG. 2 is a characteristic diagram of the power steering shown in FIG. 1. be. 1) Steering wheel, 12 Steering shaft, 13 Power cylinder, 14
...Control valve, 15...Oil pump, 16...Flow control valve, 17.
...Oil reservoir, 18...Reaction force adjustment passage, 19
...Reaction force adjustment valve, 20... Throttle, 21, 22゜23
... Response delay correction hydraulic passage, 24.25 ... Electric pressure oil injection valve, 26 ... Control unit, 27.
...Vehicle speed sensor, 28...Steering angle sensor, 29...
Supply side hydraulic passage, 30...Return pressure passage, 31゜3
2.33...Communication path. 2 maps with 1 map

Claims (1)

[Claims] (1) In a system that uses an oil pump, a control valve having a pair of reaction chambers and is operated by a steering wheel, and a power cylinder as a hydraulic circuit to steer the vehicle, the response delay correction hydraulic passage is The reaction chamber is connected to the discharge side of the oil pump, an electric pressure oil injection valve is placed in the response delay compensation hydraulic passage, and the steering wheel has a coefficient of inertia that is lower than that of a normal steering wheel. a steering angle sensor is arranged on a steering shaft connecting the steering wheel, and a control unit is electrically connected to the steering angle sensor and receives information from the steering angle sensor. The current flowing through the electric pressure oil injection valve is controlled according to the signal of the electric pressure oil injection valve, and the electric pressure oil injection valve is selectively opened and closed to selectively inject response delay correction pressure oil into the reaction force chamber. Power steering used in automobiles with special features.