JPH07110616B2 - Power steering used in automobiles - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to power steering used in motor vehicles, and in particular to a cut-off correction type power steering where the pressure of the cut-off correction pressure oil is given as a function of vehicle speed. Regarding steering.

BACKGROUND ART Generally, in an automobile, a power cylinder, a control valve having a pair of reaction chambers, an oil pump, and a flow control valve are configured in a hydraulic circuit, and the flow control valve is Regulates the flow rate of pressure oil sent from the oil pump, and its control valve operates the power cylinder by controlling the direction of pressure oil sent from the flow control valve to the power cylinder. However, a power steering system has been proposed and used in which a suitable reaction force is obtained, and at the same time, a correction pressure oil is injected into the reaction force chamber of the control valve to correct the cutting delay.

However, in this type of power steering, the pressure of the corrected pressure oil is irrelevant to the vehicle speed.
There was difficulty in responsiveness.

An object of the present invention is to suppress the operation delay of the device over the entire traveling speed of the automobile, improve the responsiveness, improve steering stability accordingly, and enable safer traveling of the automobile. The purpose is to provide power steering used in automobiles.

SUMMARY OF THE INVENTION AND CONTENTS OF CLAIMED INVENTION ACCORDING TO THE PROBLEM In connection with the above-mentioned problems, the power steering used in the automobile of the present invention is a power cylinder, a control valve having a pair of reaction force chambers, and an oil. ·pump,
And a flow control valve, and a cut-off compensation pressure setting throttle is arranged in the supply hydraulic passage connecting the oil pump to the control valve, and the cut-delay compensation passage is connected to the supply hydraulic pressure. The upstream side of the cut-delay correction pressure setting throttle of the passage is connected to the pair of reaction force chambers of the control valve, and the pair of cut-delay correction valves correspond to the pair of reaction force chambers of the control valve. The control unit is arranged in the cut-off correction passage, and the control unit is electrically connected to the vehicle speed sensor and the steering sensor, and controls a current flowing through the cut-delay correction pressure setting throttle according to a signal from the vehicle speed sensor. The throttle delay correction pressure setting throttle is adjusted so that the throttle ratio becomes smaller as the vehicle speed increases, and the pressure of the throttle delay correction pressure oil injected into the reaction force chamber is adjusted by the vehicle. Of the steering delay sensor, and controls the current flowing through the delay delay correction valve according to the signal from the steering sensor to open and close the delay delay correction valve to inject the delay delay correction pressure oil into the reaction force chamber. Is configured where
The control unit adjusts the throttle delay correction pressure setting throttle so that the throttle ratio becomes smaller as the vehicle speed increases, and the pressure of the throttle delay correction pressure oil injected into the reaction chamber is a function of the vehicle speed. Then, even in the high-speed driving range of the vehicle, the amount of pressure-lag correction pressure oil is increased.

Description of Specific Examples Specific specific examples of the power steering used in the vehicle of the present invention will be described below with reference to the drawings.

The figure schematically shows a power steering embodiment 10 for use in a motor vehicle of the invention applied to a truck.

The power steering 10 is composed of a steering wheel (not shown), a steering shaft 32, a power unit connected to a hydraulic circuit, and a link mechanism, and is provided at both ends of a front axle (not shown) of the truck. Steering a pair of front wheel shafts (not shown) that are swingably connected,
A pair of front wheels (not shown) rotatably supported by the front wheel shaft enables power steering and manual steering.

The power unit is a power cylinder 11 and a pair of reaction chambers 5.
Control valve 12 with 0,51, oil pump
13, flow control valve 14, and oil
Reservoir 15 in hydraulic circuit Supply side and return side hydraulic passage 2
7, 28, and the reaction force adjusting passage 16 connects the pair of reaction force chambers 50, 51 to each other, and the reaction force adjusting valve 17 is arranged in the reaction force adjusting passage 16 to correct the cut delay. Pressure setting throttle 18
The oil pump 13 to the control valve
The cut-off delay correction passages 19, 20 and 21 arranged in the supply-side hydraulic passage 27 connected to the control valve 12 are connected to the supply-side hydraulic passage 27 upstream of the cut-delay correction pressure setting throttle 18. Connected to the pair of reaction force chambers 50 and 51, a pair of cut-and-delay correction valves 22 and 23 are provided in the cut-and-delay correction passages 20 and 21 corresponding to the pair of reaction force chambers 50 and 51 of the control valve 12. And the control unit 24 is electrically connected to the vehicle speed sensor 25 and the steering sensor 26, and in response to signals from the vehicle speed sensor 25 and the steering sensor 26,
It controls the current flowing through the electric actuator 83 of the reaction force adjusting valve 17 and, in response to the signal from the vehicle speed sensor 25, the electric actuator 87 of the cut delay correction pressure setting throttle 18.
Control the current that flows through the solenoid valve, and further, in accordance with the signal from the steering sensor 26,
A structure for controlling the current flowing through the coils 89, 90 is provided, and in particular, the piston 44 of the power cylinder 11 is provided with the steering wheel so that the pair of front wheels can be manually steered.
The shaft 32 is ball-screw coupled to form an integral type.

The link mechanism is the sector of the power cylinder 11.
A pitman arm (not shown) fixed to the shaft 47, a drag link (not shown), a knuckle arm (not shown), and a tie rod (not shown) connecting the front wheel shafts to each other. ) And a pair of tie rod arms (not shown) which, of course, are knuckle arms at the ends of a front axle located in front of the chassis frame (not shown) of the truck. (Not shown) and a king pin (not shown) so as to be swingably connected to the front wheel shaft where the front wheels are rotatably supported.

The power cylinder 11 is the control valve
Cylinder body incorporating 12 and forming a cylinder bore 41 communicating with oil ports 45,46 connected to the cylinder ports 54,55,56 of the control valve 12
40, and a pair of cylinder chambers 42, 43 fitted in the cylinder bore 41 so as to be reciprocally slidable and connected corresponding to the oil ports 45, 46, are formed in the cylinder bore 41. It is composed of a piston 44 and a sector shaft 47 which is meshed with the piston 44 and transmits the force and movement of the piston 44 to the pitman arm. Of course, the Pitosun 44 is ball screwed to the steering shaft 32, as previously described, to allow manual steering of the pair of front wheels.

Further, the power cylinder 11 has communication passages 29 and 30 for connecting the oil port 45 of the cylinder chamber 42 and the cylinder ports 54 and 55 of the control valve 12, and
A communication passage connecting the oil port 46 of the cylinder chamber 43 and the cylinder port 56 of the control valve 12
Equipped with 31. Of course, the communication passages 29, 30 and 31 are
By its control valve 12, it is switched and connected to its supply and return hydraulic passages 27, 28 and also its power cylinder 11, control valve 12, oil pump 13, flow control valve 14, oil. The reservoir 15 and its supply and return hydraulic passages 27,2 connecting the relief valve to the hydraulic circuit
Part of 8.

In a power cylinder 11 so configured, the force and movement of its piston 44 causes its sector shaft 47, pitman arm, drag link and knuckle
It is transmitted to the front wheels via the arms and, as such, its power cylinder 11 steers the front wheels.

The control valve 12 is configured as a hydraulic reaction force type spool valve, and is incorporated in the cylinder body 40 of the power cylinder 11, and the steering shaft
A spool 52 is coupled to a spool shaft 33 fixed to an input shaft (not shown) connected to 32, and a steering wheel (not shown) fixed to the steering shaft 32 is operated to switch valves, In the hydraulic circuit, the power cylinder 11 connects the oil pump 13 and the oil reservoir 15 to the supply hydraulic passage 27, the return hydraulic passage 28, and the communication passages 29, 30, 31.
The pressure oil discharged from the oil pump 13 and flow-controlled by the flow control valve 14 is directionally controlled and supplied to the power cylinder 11, and the power cylinder 11 also works. The direction of the pressure oil is controlled, and the pressure oil is returned to the oil reservoir 15 on the suction side of the oil pump 13.

The control valve 12 is disposed in a valve body 48 having a valve bore 49, and reciprocally slidable in the valve bore 49. A pair of reaction force chambers 50, 51 are provided at both ends of the valve bore 49. And a spool 52 that forms the

The valve body 48 is incorporated into the cylinder body 40 of the power cylinder 11 and, in position, the pump port 53 and the cylinder ports 54, 55, 56 opened into the valve bore 49. And tank port
Equipped with 57.

The pump port 53 and the tank port 57 are provided with ring grooves 58, 59 for opening the inner peripheral surface of the valve bore 49.
Are formed respectively.

Further, the valve boy 48 is located in the reaction force chambers 50 and 51, and has a pair of reaction ports 60 and 61 and a pair of correction hydraulic ports 6 that are opened in the valve body 48.
It has 2,63.

The spool 52 is formed in bores 64 and 65 opened at both end faces, respectively, to increase the volume of the reaction force chambers 50 and 51.

Also, the spool 52 is in a neutral position,
Lands 66 and 67 are formed on the outer peripheral surfaces of both ends located outside the ring grooves 58 and 59, respectively, and the lands 6 and 67 are arranged between the lands 66 and 67 so as to face the ring grooves 58 and 59.
8,69 are formed on the outer peripheral surface.

Of course, on the outer peripheral surface of the spool 52 between the lands 66, 67, 68, 69 so that the spool 52 is positioned in the cylinder port 54, 55, 56 in the neutral position. Spool groove 70,71,72 is formed, those spool groove 70,7
1,72 includes its pump port 53 in its cylinder port 54,55,56 and its cylinder port as the spool 52 slides back and forth in its valve bore 49.
54,55,56 can be switched and connected to the tank port 57.

Further, the spool 52 has communication ports 73 and 74 for communicating with the corresponding bores 64 and 65 and the spool grooves 71 and 72.

The communication ports 73, 74 are connected to the reaction chambers 50, 5 as the spool 52 slides back and forth in the valve bore 49.
Switch and connect 1 to its pump port 53 and tank port 57.

Further, in this control valve 12, in order to supply the pressure oil discharged from the oil pump 13 and having the flow rate adjusted by the flow control valve 14, to the cylinder chambers 42, 43 of the power cylinder 11, The pump port 53 is connected to the supply hydraulic passage 27,
At the outlet 77 of the control valve 14, its cylinder port 54,55,56 is at its communication passage 29,30,31 its power
The cylinder 11 is connected to the oil ports 45 and 46, and the tank port 57 is connected to its oil reservoir 15 by its return hydraulic passage 28.

The oil pump 13 is driven by a diesel engine (not shown) mounted on the truck, and is connected to the pump port 53 of the control valve 12 to supply pressure oil to the power cylinder 11. It is arranged in the supply side hydraulic passage 27 of the hydraulic circuit that connects the oil reservoir 15, sucks up and pressurizes the oil in the oil reservoir 15, and discharges the pressure oil that is almost proportional to the rotation speed of the diesel engine. I try to get the amount. Of course, the oil pump 13 is manufactured in the same structure as the oil pump used for the existing power steering, and therefore the description thereof will be omitted.

The flow control valve 14 is arranged in the hydraulic circuit in a supply hydraulic passage 27 connecting the control valve 12 to the oil pump 13 and the oil reservoir 15 and also to the control valve bypass 79. Is connected to the return hydraulic passage 28.

The flow control valve 14 is
An inlet 76 connected to the discharge side of the pump 13, an outlet 77 connected to the pump port 53 of its control valve 12,
And a valve casing 75 having a return port 78 connected to the return-side hydraulic passage 28, and the valve casing.
A configuration including an oil return control spool (not shown) that is reciprocally slidably disposed within 75, adjusts the flow rate of the pressure oil sent to the inlet 76 thereof, and adjusts the predetermined flow rate to that. It also sends it to outlet 77 and returns the excess flow of pressure oil from its return port 78 to its oil reservoir 15 via a control valve bypass 79.

Of course, the flow control valve 14 is manufactured in the same structure as the flow control valve used in the existing power steering, and the detailed description of the structure will be omitted.

The reaction passage 16 is the control valve
Twelve pairs of reaction force chambers 50 and 51 are connected to each other.

That is, the reaction passage 16 has one reaction chamber 50.
One end is connected to the reaction port 60 opened to the other side, and the other end is connected to the reaction port 61 opened to the other reaction force chamber 51, and the reaction force chambers 50 and 51 are connected to each other.

Of course, the reaction passage 16 uses a pipe having a predetermined inner diameter and length, but without using such a pipe, the valve body 48 or the cylinder
The body 40 may be perforated.

The reaction force adjusting valve 17 includes a spool chamber (not shown), a valve body 80 having a pair of ports 81 and 82 communicating with the spool chamber, and a reciprocating slide in the spool chamber. A spool (not shown) that is movably arranged and that changes the passage cross-sectional area in the spool chamber according to the reciprocal sliding, and an electric actuator 83 that reciprocally slides the spool in the spool chamber. Has been done.

Therefore, as the spool is reciprocally slid in the spool chamber by the electric actuator 83, the flow rate of the pressure oil flowing between the ports 81 and 82 is adjusted, and as a result, the control valve is adjusted. 12 reaction chambers 5
The pressure in 0,51 is adjusted.

Further, the pressure adjusting valve 17 has been described as a spool type, but the form is arbitrary as long as it regulates the flow rate of the pressure oil flowing between the ports 81 and 82, and for example, a rotary type. May be configured as.

The delay adjustment pressure setting throttle 18 is
It is manufactured in a rotary valve type where it is driven by a current controlled by the unit 24, it is discharged from the oil pump 13, and the pressure oil flowing to the control valve 12 via the flow control valve 14 is squeezed, The pressure oil flowing in the cut-off correction passages 19, 20, 21 is, in other words, the pressure of the cut-delay correction pressure oil injected into the pressure chambers 50, 51 of the control valve 12 is given as a function of the vehicle speed. , As the vehicle speed increases, the pressure of the delay compensation pressure oil increases.
So-called increase.

This cut-delay compensating pressure setting restrictor 18 includes a valve bore (not shown), a valve body 84 with inlet and outlet ports 85, 86 communicating with the valve bore, and a through-hole (not shown). ), And a rotary valve (not shown) rotatably fitted in the valve bore and an electric actuator 87 for rotating the rotary valve in the valve bore. Since the unit 24 controls the electric current flowing through its electric actuator 87 in response to the vehicle speed, the electric actuator 87 is driven by the controlled electric current, which causes the rotary valve to rotate in its valve bore. The passage cross-sectional area of the through-hole is changed according to the rotation, and specifically, the passage cross-sectional area of the through-hole is changed small as the vehicle speed increases. So, the so-called applying pressure switching delay correction pressure oil flowing through the switching delay correction path 19 by changing small diaphragm diameter as a function of vehicle speed.

The electric actuator 87 is a servo motor, which connects a motor shaft 88 to the rotary valve and also a coil (not shown) to the control unit.
Control unit 24 by connecting to 24 output circuits
Driven by an electric current controlled by, the rotary valve rotates into the valve bore and changes the passage cross-sectional area of the through-hole.

The cut-off delay correction pressure setting throttle 18 is configured as a rotary valve type, but this can reduce the flow rate of the pressure oil flowing from its inlet port 85 to its outlet port 86, that is, it can change the so-called throttle diameter. As long as it is one, the form is arbitrary, and for example, it can be configured as a needle valve type or a spool valve type.

Further, the electric actuator 87 was a servo motor, but this can be appropriately changed as the cut-delay correction pressure setting throttle 18 is embodied as a rotary valve type, a needle valve type, a spool valve type or the like. , A step motor or an electromagnetic coil can be used.

The cut-delay correction passages 19, 20, 21 are connected to each other, and the cut-delay correction passage 19 is connected to the supply-side hydraulic passage 27 upstream of the cut-delay correction pressure setting throttle 18 and the cut-off correction passage 19 is connected to the supply-side hydraulic passage 27. The delay correction passages 20 and 21 are
It is connected to compensating hydraulic ports 62, 63 formed in the valve body 48 of the valve 12.

The delay delay correction passage where such a branch oil passage is formed
19, 20 and 21 are connected to the pair of reaction force chambers 50 and 51 of the control valve 12 on the upstream side of the cut-off delay correction pressure setting throttle 18 of the supply side hydraulic passage 27, and the control unit 24 The cut-delay correction pressure setting throttle 18 which is driven by a controlled electric current guides the cut-delay correction pressure oil which gives a pressure as a function of vehicle speed to a pair of reaction force chambers 50 and 51 of the control valve 12, and The operation delay of the control valve 12 is avoided, and the so-called delay of the power steering 10 can be corrected.

The pair of cut-off correction valves 22 and 23 are electromagnetic two-way control valves and are arranged in the corresponding cut-delay correction passages 20 and 21, respectively.

Further, the cut-off delay correction valves 22 and 23 are connected to the solenoid coil 8
The 9,90 is connected to the output circuit of the control unit 24, and the control unit 24 drives the controlled current to control the cut-off delay pressure oil whose pressure is given as a function of vehicle speed. Reaction chamber 50,51 of valve 12
Inject selectively depending on the steering.

The control unit 24 electrically connects the input side to the vehicle speed sensor 25 and the steering sensor 26,
Further, the output side is electrically connected to the reaction force adjusting valve 17 and the electric actuators 83 and 87 of the cut-delay correction pressure setting throttle 18 and the solenoid coils 89 and 90 of the cut-delay correction valves 22 and 23, respectively. In response to signals from the sensors 25, 26, their electric actuators 83, 87 and solenoids
It controls the current flowing through the coils 89 and 90.

That is, the control unit 24 controls the current flowing through the electric actuator 83 of the reaction force adjusting valve 17 in accordance with the signals from the vehicle speed sensor 25 and the steering sensor 26 to slide the spool into the spool chamber. The spool chamber is moved to change the passage cross-sectional area, the reaction force chambers 50 and 51 generate a hydraulic reaction force according to the vehicle speed, and the reaction force is switched off according to a signal from the vehicle speed sensor 25. The electric current flowing through the electric actuator 87 of the delay correction pressure setting throttle 18 is controlled to change the rotary valve to that valve.
The pressure oil which is rotated in the bore, changes the passage cross-sectional area of the through-hole formed in the rotary valve, and is located upstream of the cut-off delay correction pressure setting throttle 18 of the supply-side hydraulic passage 27, Pressure is applied to the delay-giving correction pressure oil flowing in the delay-giving correction passage 19 as a function of vehicle speed, and the steering sensor
The current flowing through the solenoid coils 89, 90 of the cut-delay correction valves 2, 23 is controlled according to the signal from the switch 26, and the cut-delay correction valves 22, 23 are selectively opened. After selectively passing through the correction passages 20 and 21, the cut-off delay correction pressure oil is selectively injected into the reaction chambers 50 and 51, and the control
It is configured to suppress the operation delay of the valve 12 and avoid the delay of the power steering 10 thereof. Of course, the control unit 24 is composed of input and output circuits, a memory circuit, an arithmetic circuit, a control circuit and a power supply circuit, and the power supply circuit also shares the battery 34 of the truck.

The vehicle speed sensor 25 detects the traveling speed of the truck and is arranged on the output shaft of a transmission (not shown) mounted on the truck, and the steering sensor 26 detects the steering shaft 32 of the steering shaft 32. Rotational speed,
A rotation sensor that detects a rotation direction and a rotation angle, and is arranged around the steering shaft 32 at a predetermined position of the steering shaft 32. Of course, as the steering sensor 26, it is also possible to use a built-in type steering wheel.

Next, the operation of the above-described power steering 10 will be described with reference to the running state of the truck.
The pump 13 is driven, and the flow rate of the pressure oil discharged from the oil pump 13 is adjusted by the flow control valve 14, flows through the supply side hydraulic passage 27, and the inlet of the cut-delay correction pressure setting throttle 18 Sent to port 85.

At the same time, the control unit 24 inputs signals from the vehicle speed sensor 25 and the steering sensor 26,
The electric current flowing through the electric actuator 83 of the reaction force adjusting valve 17, the electric actuator 87 of the cut-delay correction pressure setting throttle 18, and the solenoid coils 89, 90 of the cut-delay correction valves 22, 23 is controlled to control the vehicle speed and steering. A suitable hydraulic reaction force is obtained in the reaction force chambers 50, 51 of the control valve 12, and the cut-delay correction pressure oil whose pressure is given as a function of vehicle speed is the upstream of the cut-delay correction pressure setting throttle 18. On the supply side hydraulic passage 27, and is ready to flow to the cut-off delay correction passages 19, 20, 21.

Then, at that time, the pressure oil that has passed through the cut-delay correction pressure setting throttle 18 flows through the supply-side hydraulic passage 27 on the downstream side of the cut-delay correction pressure setting throttle 18, and the pump port 53 of the control valve 12 is provided. If the steering wheel is in the neutral position, as shown, then the spool 52 is also placed in the neutral position,
The pressure oil sent to the pump port 53 is returned to the oil reservoir 15 from the tank port 57 via the return hydraulic passage 28.

Therefore, the steering force when turning the steering wheel will be described.

Now, if the truck is traveling at a low speed, the control unit 24 inputs signals from the vehicle speed sensor 25 and the steering sensor 26, calculates based on the input signals, and calculates the reaction force of the reaction force adjusting valve 17. Determines the current flowing through the electric actuator 83, and the electric actuator of the reaction force adjusting valve 17
In the reaction force regulating valve 17, the spool is slid into the spool chamber by the electric actuator 83, and the passage cross-sectional area in the spool chamber is widened because the current flowing in the spool chamber 83 is controlled. .

In such a state, when the steering wheel is turned to either one, correspondingly, the spool 52 of the control valve 12 is slid to either the left or the right.

Then, depending on the sliding direction of the spool 52, the pressure oil is either left or right of the cylinder chambers 42, 43 of the power cylinder 11 and the reaction force chambers 50, 51 of the control valve 12. Sent to either one of

For example, if the spool 52 is slid to the right in the figure, the pump port 53
To the cylinder port 56 via the spool groove 71, and the tank port 57 to the cylinder port 55 via the spool groove 72 of the spool 52,
The pressure oil discharged from the oil pump 13 is sent to the cylinder chamber 43 of the power cylinder 11 through the communication passage 31, and the piston 44 is slid to the right side in the drawing, and the power cylinder 11 The pressure oil in the cylinder chamber 42 is returned to the oil reservoir 15 via the communication passages 29, 30 and the return hydraulic passage 28.

As such, when the pressure oil is supplied, a part of the pressure oil is sent to the reaction force chamber 50 via the communication port 73 and the bore 64.

The reaction force at the time of such steering is given by the hydraulic pressure in the reaction force chamber 50, but as described above, during low speed traveling,
Since the passage sectional area of the reaction force adjusting valve 17 is wide,
The pressure oil in the reaction force chamber 50 passes through the reaction passage 16 and flows into the other reaction force chamber 51 without being extremely throttled by the reaction force adjusting valve 17.

Further, when 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 force chamber 51 passes through the return hydraulic passage 28 and Returned to oil reservoir 15.

Therefore, the pressure drop by the reaction force adjusting valve 17 becomes small, the pressure difference between the left and right reaction force chambers 50, 51 becomes small, and the pressure oil in the reaction force chamber 50 slides on the spool 52. On the other hand, the resistance does not become large, in other words, the steering at low speed traveling is performed with a small operation force.

Also, if the spool 52 of the control valve 12 is slid to the left side in the figure, the pump port 53 is inserted into the spool groove 70 of the tank port.
57 is connected to the spool groove 71, respectively, and the pressure oil discharged from the oil pump 13 is sent to the cylinder chamber 42 of the power cylinder 11 via the communication passage 29, and the piston 44 thereof is on the left side in the figure. Sliding on its power
The pressure oil in the cylinder chamber 43 of the cylinder 11 is returned to the oil reservoir 15 via the communication passage 31 and the return hydraulic passage 28.

Contrary to the case described above, the pressure oil in the reaction force chamber 51 passes through the reaction passage 16 and is sent to the reaction force chamber 50 without being extremely throttled by the reaction force adjustment valve 17, and the reaction The pressure oil in the force chamber 50 is returned to the oil reservoir 15 via the bore 64, the communication port 73, the spool groove 71, the tank port 57 and the return hydraulic passage 28.

Therefore, as in the case described above, the pressure drop by the reaction force adjusting valve 17 becomes small, the pressure difference between the left and right reaction force chambers 50, 51 becomes small, and the pressure oil in the reaction force chamber 51 becomes spool
There is no great resistance to the sliding of 52, and steering is performed with a small operating force.

Also, as in the above case, when the truck is stationary, the traveling speed is zero, so the reaction force adjustment valve
At 17, the passage cross-sectional area is maximized, and the pressure difference between the reaction force chambers 50 and 51 becomes extremely small, so that the stationary cutting is performed with an extremely small operating force.

Further, if the truck is traveling at high speed, the control unit 24 inputs signals from the vehicle speed sensor 25 and the steering sensor 26, calculates based on the input signals, and calculates the reaction force of the reaction force adjusting valve 17. Since the current flowing through the electric actuator 83 is determined and the current flowing through the electric actuator 83 of the reaction force adjusting valve 17 is controlled, the reaction force adjusting valve 17
In, the spool is the electric actuator
It is slid into the spool chamber by 83 and the passage cross-section in the spool chamber is narrowed to suit the vehicle speed in this case.

In such a state, when the steering wheel is turned to the left or right, as in the case of the low speed running described above, the spool 52 of the control valve 12 is turned to the left or right correspondingly. It is slid on one side.

Then, depending on the sliding direction of the spool 52, the pressure oil is sent to one of the cylinder chambers 42, 43 of the power cylinder 11, the piston 44 is slid, and the pressure oil A part of it is sent to either one of the reaction force chambers 50 and 51, but since the spool of the reaction force adjusting valve 17 and the passage sectional area in the chamber are narrowed, the pressure drop by the reaction force adjusting valve 17 is reduced. Becomes larger, the pressure difference between the left and right reaction force chambers 50, 51 becomes larger, and as a result, one of the pressure oils in the reaction force chambers 50, 51 becomes a large resistance against sliding of the spool 52. .

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

Next, the turning delay correction when the steering wheel is turned will be described. Of course, this cut-off delay correction is performed simultaneously with the reaction force adjustment described above.

The control unit 24 inputs a signal indicating the traveling speed of the truck from the vehicle speed sensor 25, calculates based on the input signal, and supplies a current to the electric actuator 87 of the cut-delay correction pressure setting throttle 18. And the electric current flowing through the electric actuator 87 of the cut-delay correction pressure setting throttle 18 is controlled, the rotary valve in the cut-delay correction pressure setting throttle 18 is controlled by the electric actuator 87. The passage cross-sectional area of the through hole formed in the rotary valve is changed by rotating the inside of the rotary valve, and the pressure in the supply hydraulic passage 27 upstream of the cut-delay correction pressure setting throttle 18 is always a function of the vehicle speed. The delay delay correction pressure oil given by is obtained.

In this way, the cut delay correction pressure oil at the pressure given as a function of the vehicle speed is changed to the cut delay correction pressure setting throttle 18
Since it is obtained in the supply side hydraulic passage 27 on the upstream side of the control unit, if the steering wheel is turned in either the left or right direction, the control unit
The reference numeral 24 designates a signal in either the left or right direction when the steering wheel is turned off, which is inputted from the steering sensor 26, and is operated on the basis of the input signal to calculate the solenoid of the turn-off delay correction valves 22 and 23.・ Determine the current flowing through either coil 89 or 90 and control the current flowing through either solenoid coil 89 or 90 of that delay delay correction valve 22,23 to control that delay delay valve 22,23. Open either one of.

As such, the steering delay correction valve 22,2 is provided in correspondence with either the left or right direction in which the steering wheel is turned.
When any one of 3 is opened, the cut delay correction pressure oil that has flowed from the supply hydraulic passage 27 upstream of the cut delay correction pressure setting throttle 18 to the cut delay correction passage 19 has its cut delay correction passage. It is injected into either one of the reaction force chambers 50 and 51 of the control valve 12 through either one of 20 and 21.

In this way, the cut-off delay correction pressure oil whose pressure is given as a function of vehicle speed is injected into one of the reaction force chambers 50 and 51 of the control valve 12 in accordance with the steering direction of the steering wheel. Therefore, the operation delay of the control valve 12 is suppressed, the responsiveness of the power cylinder 11 is improved, and the delay of the front wheels due to the steering of the steering wheel is prevented.

In particular, the pressure of the cut-off delay correction pressure oil is given as a function of the vehicle speed, that is, as the traveling speed of the truck is increased, the rotary valve of the rotary valve is reduced in the direction of decreasing the passage cross-sectional area of the passage. So that the throttle ratio is reduced by rotating the control unit into the valve bore to reduce the throttle ratio.
Since it is adjusted by 24, the pressure of the cut-off delay correction pressure oil is gradually increased with the increase of the traveling speed of the truck, that is, with the increase of the so-called vehicle speed, and when the truck travels at high speed. In addition, the amount of the cut delay correction pressure oil that is injected into the reaction force chambers 50 and 51 of the control valve 12 is increased, and the effect of the cut delay correction is sufficiently obtained even in the high-speed traveling range of the truck. To be

Also, if the steering wheel is turned in the opposite direction to that described above, the power steering 10 is operated in substantially the opposite manner to steer its front wheels in the opposite direction to that described above. In addition, the delay of the front wheels due to the steering of the steering wheel is prevented.

In the power steering 10 described above, the control valve 12 is described as being embodied as the spool type, but the control valve 12 can be embodied as the rotary type.

Further, in the power steering 10 described above, the power unit was described as being embodied as an integral type, but the power unit is also a semi-integral type.
It is also possible to embody the linkage type.

As will be apparent from the specific embodiments of the present invention described above with reference to the drawings, those having ordinary skill in the art to which the present invention pertains,
The subject matter of this invention is readily embodied in alternative forms which are derived from the nature and substance of the invention and which are objectively admitted to incorporate them. Of course, the contents of the present invention are commensurate with the subject of the invention and are essential to the establishment of the invention.

Benefits of the Invention As can be seen from the above, the power steering used in the motor vehicle of the present invention includes a power cylinder, a control valve having a pair of reaction chambers, an oil pump, a flow control valve, and a switching valve. Includes a lag compensation pressure setting throttle, a lag compensation passage, a pair of lag compensation valves, and a control unit, where the lag compensation pressure setting throttle connects the oil pump to its control valve. The feed delay hydraulic passage connects the upstream side of the feed delay hydraulic pressure setting throttle of the feed hydraulic passage to the pair of reaction force chambers of the control valve. A lag compensation valve is located in the lag compensation passage corresponding to the pair of reaction chambers of the control valve, and the control valve is The roll unit is electrically connected to the vehicle speed sensor and the steering sensor, controls the current flowing through the throttle delay correction pressure setting throttle according to the signal from the vehicle speed sensor, and reduces the throttle ratio as the vehicle speed increases. To adjust the cut-delay correction pressure setting throttle to give the pressure of the cut-delay correction pressure oil injected into the reaction chamber as a function of vehicle speed, and
The current flowing through the cut-delay correction valve is controlled according to the signal from the steering sensor, the cut-delay correction valve is opened and closed to inject the cut-delay correction pressure oil into the reaction force chamber. In the power steering used for, the control unit responds to the signal from the vehicle speed sensor, and adjusts the throttle delay correction pressure setting throttle so that the throttle ratio becomes smaller as the vehicle speed becomes the signal. The delay adjustment pressure oil is adjusted, and accordingly, the delay adjustment pressure oil in the supply-side hydraulic passage upstream of the cut delay correction pressure setting throttle is given a pressure as a function of vehicle speed, that is, gradually increases as the vehicle speed increases. It is provided with increased pressure and its control unit responds to the signal from its steering sensor, i.e. in response to the steering direction of the steering wheel, with its delay compensation. By opening and closing the valve, the delay delay correction pressure oil is selectively injected into a pair of reaction force chambers of the control valve to suppress the operation delay of the control valve and improve the responsiveness of the power cylinder. And, the delay of the front wheels against the steering of the steering wheel is prevented, and especially when the car is traveling at high speed, the pressure of the delay delay correction pressure oil is increased corresponding to the high speed to control it. The amount of the cut-off correction pressure oil injected into the reaction chamber of the valve is increased, and the cut-off of the front wheels due to steering of the steering wheel is sufficiently prevented even in the high-speed driving range of the automobile. In this way, the operation delay of the device is suppressed over the entire traveling speed of the vehicle, the response is improved, the steering stability is improved accordingly, and the automatic Safer driving is secured to a result, it is very useful and practical for automobiles.

[Brief description of drawings]

The figure is a schematic diagram showing a specific example of the power steering used in the automobile of the present invention applied to a truck. 11 …… power cylinder, 12 …… control valve, 13 …… oil pump, 14 …… flow control valve, 15 …… oil reservoir, 16 …… reaction force adjusting passageway, 17 …… reaction force Adjusting valve, 18 …… Delay delay compensation pressure setting throttle, 19,20,21 …… Delay delay compensation passage, 22,23 …… Delay delay compensation valve, 24 …… Control unit, 27 …… Supply side hydraulic passage, 28 …… Return side hydraulic passage, 29,30,31 …… Communication passage.

Claims (1)

[Claims] 1. A steering comprising a power cylinder, a control valve having a pair of reaction chambers, an oil pump, and a flow control valve, wherein the cut-off delay correction pressure setting throttle restricts the oil pump. Located in the supply-side hydraulic passage connected to the control valve, the cut-off delay passage connects the upstream side of the supply-side hydraulic passage to the cut-off correction pressure setting throttle to the pair of reaction chambers of the control valve. Then, a pair of cut-delay correction valves are arranged in the cut-delay correction passage corresponding to the pair of reaction force chambers of the control valve,
The control unit is electrically connected to the vehicle speed sensor and the steering sensor, controls the current flowing through the throttle delay correction pressure setting throttle according to the signal from the vehicle speed sensor, and increases the throttle ratio as the vehicle speed increases. The cut-off delay correction pressure setting throttle is adjusted so as to reduce, and the pressure of the cut-off delay correction pressure oil injected into the reaction force chamber is given as a function of the vehicle speed.
In automobiles that are characterized by controlling the current flowing through the dead-lag correction valve according to the signal from the steering sensor, opening and closing the dead-lag correction valve, and injecting the dead-lag correction pressure oil into the reaction force chamber. Power steering used.