JP2528276B2 - Power steering used in vehicles - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a power steering used in a vehicle,
In particular, it relates to a power steering for compensating for delay.

BACKGROUND ART In general, speed-sensitive power steering has become widespread in automobiles, but this type of power steering reduces response delay and increases maneuverability when sensitivity is increased. Increased turn angle and yaw rate, increased steering sensitivity, reduced maneuverability and safety.

An object of the present invention is to reduce the response delay of the vehicle behavior with respect to the steering wheel operation without making the steering wheel hypersensitive and suppress the increase of the tire turning angle and the yaw rate with respect to the steering wheel angle to improve the maneuverability and safety. It is to provide a power steering used in a vehicle having a speed sensitive characteristic.

Summary of the Invention Corresponding to the Problem and Content of the Claimed Invention In relation to the above-mentioned problem, a power steering used in a vehicle of the present invention is a power cylinder having a pair of cylinder chambers, an oil pump, and a pair of cylinders. In a control valve having a reaction chamber, a flow control valve, and an oil reservoir configured and steered in a hydraulic circuit, the throttle restricts the flow control valve to the control valve in the hydraulic circuit. The delay delay compensating hydraulic pipe is arranged in the supply side hydraulic pipe to communicate with, and the upstream side of the throttle of the supply side hydraulic pipe is connected to the pair of reaction force chambers of the control valve or the pair of cylinder chambers of the power cylinder. In contact with the control valve, a pair of cut-and-delay compensating valves Corresponding to a pair of cylinder chambers of a cylinder, it is arranged in the cut-off delay compensating hydraulic pipe, and the compensating pressure oil can be injected into the reaction force chamber or the cylinder chamber, and the controller injects the compensating pressure oil. The energization pattern that determines the energization time of the valve delay compensation valve corresponding to the time is input in advance, a signal is input from the steering amount sensor, the energization time is determined in comparison with the energization pattern, and the steering wheel is turned off. First, a current is passed through the solenoid coil of the cut-delay correction valve in the cutting direction for the determined energization time to open the cut-delay correction valve in the cutting direction, and the correction pressure oil is controlled to control it.
It is injected into the reaction chamber in the valve cutting direction or into the cylinder chamber in the cutting direction of the power cylinder, and at the beginning of the handle return, a current is supplied for the determined energizing time for the solenoid valve of the cut delay compensation valve in the returning direction. Flowing in a coil to open the return delay delay compensating valve, and injecting compensating pressure oil into the return reaction chamber of the control valve or the return cylinder chamber of the power cylinder, and It reduces the response delay of the vehicle behavior to the steering wheel operation without damaging the shock of the correction pressure oil injection and making the steering wheel hypersensitive, suppressing the increase of the tire angle and the yaw rate relative to the steering wheel angle, and the steering wheel return. improves.

The power steering used in the vehicle of the present invention is a power cylinder having a pair of cylinder chambers,
Oil pump, control with a pair of reaction chambers
Valves, flow control valves, and oil reservoirs that are configured in a hydraulic circuit for steering, in which the throttle is connected to the supply hydraulic line that connects the flow control valve to the control valve in the hydraulic circuit. A delay delay compensating hydraulic pipe is arranged to connect the upstream side of the throttle of the supply side hydraulic pipe to the pair of reaction force chambers of the control valve or the pair of cylinder chambers of the power cylinder to provide a pair of delay delays. A compensating valve is arranged in the delay delay compensating hydraulic pipe corresponding to the pair of reaction chambers of the control valve or the pair of cylinder chambers of the power cylinder, and the compensating pressure oil is arranged in the reaction chamber or the compensating chamber. Allows injection into the cylinder chamber,
Then, the controller previously inputs an energization pattern that determines the energization time of the cut-off delay correction valve corresponding to the injection time of the correction pressure oil, and inputs a signal from the steering amount sensor, and compares it with the energization pattern. To determine the energizing time,
Then, at the beginning of turning the steering wheel, a current is applied to the solenoid coil of the cut-delay correction valve in the cutting direction for the determined energization time to open the cut-delay correction valve in the cutting direction, and the correction pressure oil is controlled.・ Injection into the reaction chamber in the valve cutting direction or the cylinder chamber in the cutting direction of the power cylinder, and to return the handle,
The current is passed through the solenoid coil of the return-direction delay-and-delay compensation valve for the determined energizing time corresponding to the time when the handle is substantially returned, and the return-direction-and-delay-compensation valve is opened, and the compensation pressure is adjusted. Oil is injected into the reaction force chamber of the control valve in the return direction or the cylinder chamber in the return direction of the power cylinder, and the injection of the correction pressure oil is mitigated to handle the steering wheel without desensitizing the steering wheel. It reduces the response delay of the vehicle behavior, suppresses the increase in the tire turning angle and the yaw rate with respect to the steering wheel angle, and improves the steering wheel return.

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.

FIG. 1 schematically shows an embodiment 10 of the power steering used in the vehicle of the present invention applied to a truck.

This power steering 10 is a linkage type embodiment for steering the front wheels.
Arm (not shown), drag link (not shown),
Link lever (not shown), conventing
Rod (not shown), pitman arm (not shown), steering gear box (not shown), handle shaft (steering shaft,
(Not shown), a handle (a steering wheel, not shown), a power cylinder 11 having a pair of cylinder chambers 34, 35, an oil pump 12, a pair of reaction chambers 46, 4
7, a control valve 13, a flow control valve 14, an oil reservoir 15, a reaction force adjusting passage 16 for connecting a pair of reaction force chambers 46, 47 of the control valve 13 to each other, and a reaction force chamber 46, The reaction force adjusting valve 17 arranged in the reaction force adjusting passage 16 for 47, its control
A throttle 18 arranged in the supply hydraulic pipe 62 of the hydraulic circuit between the valve 13 and its flow control valve 14, connecting the supply hydraulic pipe 62 to one end on the upstream side of the throttle 18, and A cut delay that branches the other end into a pair of cut delay correction hydraulic branch pipes 20 and 21, and connects the cut delay correction hydraulic branch pipes 20 and 21 corresponding to the reaction force chambers 46 and 47 of the control valve 13. Compensation hydraulic pipe 19, a pair of delay delay compensation valves 22 and 2 arranged corresponding to the delay delay compensation hydraulic branch pipes 20 and 21.
3, a controller 24, a vehicle speed sensor 25, and a steering amount sensor 26 are provided, and a hydraulic reaction force adapted to the vehicle speed is obtained therein, and a steering delay, in other words, a response delay to steering is provided. Is reduced to suppress an increase in the tire cutting angle and yaw rate with respect to the steering wheel angle.

As such, the power steer rig 10 is composed of a part configured in the link mechanism and a part configured in the hydraulic circuit.・ Cylinder 11 incorporates valve body 38 of its control valve 13 and power cylinder port 4 of its control valve 13
Power cylinder body 30 with cylinder bore 31 communicating with oil ports 36,37 connected to 3,44,45
And a power for forming a pair of cylinder chambers 34, 35 fitted in the cylinder bore 31 in a reciprocating sliding manner and connected corresponding to the oil ports 36, 37 in the cylinder bore 31. The power cylinder 32 is composed of a piston 32 and a piston rod 33 having one end fixed to the power piston 32 and the other end extending to and from the outside of the power cylinder body 30. Body 30
Is rotatably connected to its link lever and its piston rod 33 to a chassis frame (not shown).

In addition, the power cylinder 11 has a cylinder chamber 34
Oil passage 36 connecting the oil port 36 of the control valve 13 with the power cylinder port 44 of the control valve 13, and the oil port 37 of the cylinder chamber 35 and the power cylinder ports 43, 45 of the control valve 13 It is provided with communication passages 65 and 66 for communicating with.

With its power cylinder 11 so configured,
The movement of the power piston 32 becomes the movement of the power cylinder body 30 and the piston rod 33 and is transmitted to the front wheels via the link lever, the drag link, and the knuckle arm, and so on. The power cylinder 11 steers its front wheels.

The oil pump 12 is driven by an internal combustion engine (not shown) mounted on the truck,
In order to supply pressure oil to the cylinder 11, it is arranged in the supply side hydraulic pipe 62 of the hydraulic circuit where the oil reservoir 15 is connected to the pump port 41 of the control valve 13, Is sucked up and pressurized to obtain a discharge amount of the pressure oil which is almost proportional to the rotation speed of the internal combustion engine. Of course, the oil pump 12 is manufactured in the same structure as the oil pump used for the existing power steering, and the description thereof will be omitted.

The control valve 13 is configured as a hydraulic reaction type spool valve and is incorporated in the power cylinder body 30 of the power cylinder 11, and connects the spool shaft 80 to the convening rod. , Its pitman arm, steering gear box, and steering shaft are valved by its steering wheel and, in its hydraulic circuit, its oil pump 12 and oil by its power cylinder 11. -Pipes for connecting the reservoir 15, namely, the supply-side hydraulic pipe 62, the return-side hydraulic pipe 63,
And the oil pump located in the communication passages 64, 65, 66
The pressure oil discharged from 12 is directionally controlled and supplied to the power cylinder 11, and the pressure oil worked in the power cylinder 11 is directionally controlled, and the oil is the suction side of the oil pump 12. -Return the pressure oil to the reservoir 15.

The control valve 13 has a valve body 38.
And a control valve spool 40 that is reciprocally slidably arranged in the spool bore 39 of the valve body 38.
Including its control valve spool 40 with its spool shaft 80, conventing rod, pitman arm, steering gear box, and steering shaft via its steering wheel through its spool bore. The power cylinder 11 slides back and forth in a pair of cylinder chambers 34, 3
Switch the pressure oil flowing to 5, and along with the switching operation,
The pressure oil returned from the cylinder chambers 34, 35 to the oil reservoir 15 is directionally controlled.

The valve body 38 has a spool bore 39 having a predetermined inner diameter and a predetermined length formed therein, and the spool body 39 has a predetermined spacing on one side (upper side in FIG. 1). A pump port 41 and a tank port 42 connected to the bore 39 are formed, and the other side (in the figure,
(The lower side) at approximately equal intervals and their spool bore
3 power cylinder ports 43,44 connected to 39
Forming 45.

The pump port 41 is connected to the discharge side of the oil pump 12 via a supply side hydraulic pipe 62, and
The tank port 42 is connected to the oil reservoir 15 via the return hydraulic line 63, and the power cylinder ports 44, 43, 45 are connected to the communication passages 64, 65, 66.
Is connected to the cylinder chambers 34 and 35 of the power cylinder 11 via.

In addition, the valve body 38 has its control valve spool in its spool bore 39.
It forms a pair of reaction force ports 48, 49 which are used to connect the reaction force chambers 46, 47 formed on both sides of 40 to each other.

The control valve spool 40 is provided with bores 50, 51 opened at both end faces thereof, and is reciprocally slidably disposed in the spool bore 39.
When fitted in the bore 39, the bores 50, 51 are
In the spool bore 39, the control
A pair of reaction chambers 4 formed on both sides of the valve spool 40.
Increase the volume of 6,47.

Further, when the control valve spool 40 slides back and forth in the spool bore 39, it supplies pressure oil to one of the reaction force chambers 46 and 47 depending on the sliding direction of the control valve spool 40. A pair of reaction force communication ports 52 and 53 are provided.

In particular, the control valve spool 40 has spool grooves 54, 55, 56 formed on the outer peripheral surface thereof at predetermined axial intervals with respect to the reaction force communication ports 52, 53.

Of course, in the spool grooves 55, 56, reaction force communication ports 52, 53 communicating with the reaction force chambers 46, 47 are opened correspondingly, and as a result, the reaction force communication ports 52, 53 are The position of the spool grooves 55, 56 within the spool bore 39 associated with the movement of the control valve spool 40 causes the power cylinder ports 44, 45 to move into the reaction chamber 46,
47, and its spool groove 54 connects pump port 41 to power cylinder port 43.

Furthermore, the control valve spool 40 is
In response to the steering operation, the spool body extended through the valve body 38 so as to be reciprocally slid in the spool bore 39.
The center of the spool (spool center) is connected to the tip of the shaft 80. Of course, the spool shaft
The 80 has its rear end connected to its convening rod.

So configured, and its supply side hydraulic piping 6
2, the return side hydraulic pipe 63, and its control valve 13 arranged in the communication passages 64, 65, 66,
It has its valve body 38 with compensating hydraulic ports 57, 58 opened corresponding to 46, 47.

The flow control valve 14 is a hydraulic pipe that connects the control valve 13 to the oil pump 12 and the oil reservoir 15 in the hydraulic circuit, that is, the supply side hydraulic pipe 62 and the return side hydraulic pipe.
It is located at 63.

The flow control valve 14 includes a pump port 59 connected to the discharge side of the oil pump 12, a control valve port 60 connected to the pump port 59 side of the control valve 13, and A casing having a return port 61 connected to the suction side of the oil pump 12, and an oil return control unit arranged in the casing so as to be able to slide back and forth.
With a configuration including a spool, the flow rate of the pressure oil sent to the pump port 59 side is adjusted, a predetermined flow rate is sent to the control valve port 60 side, and the surplus flow rate of the pressure oil is The return port 61 returns to the oil reservoir 15 via a control valve bypass 67.

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 is omitted.

The reaction force adjusting passage 16 has one end connected to the reaction force port 48 and the other end connected to the reaction force port 49, and these reaction force chambers 46, 47 are connected.
To communicate with each other, and enable the movement of pressure oil between the reaction force chambers 46 and 47 according to the movement of the control valve spool 40 in the control valve 13.

The reaction force adjusting valve 17 is arranged in the reaction force adjusting passage 16, adjusts the amount of pressure oil flowing between the reaction force chambers 46, 47, and adjusts the pressure in the reaction force chambers 46, 47.

The reaction force adjusting valve 17 includes a spool chamber (not shown), a valve body 68 having a pair of ports 69 and 70 connected to the spool chamber, and a reciprocating sliding movement in the spool chamber. And a spool that is movably disposed and that changes its passage cross-section within its spool chamber in response to its reciprocating sliding movement.

Therefore, the flow rate of the pressure oil flowing between the ports 69 and 70 is adjusted in accordance with the reciprocal sliding movement of the spool, in other words, the adjustment of the pressure in the reaction force chambers 46 and 47 of the control valve 13. Is done.

Of course, the reaction force adjusting valve 17 has a pair of ports 69, 70.
The form is arbitrary as long as the flow rate of the pressure oil flowing between them can be adjusted, and for example, a rotary type can also be used.

The reaction force adjusting valve 17 is opened and closed by the electric actuator 71. That is, the electric actuator 71 is
The spool of the reaction force adjusting valve 17 is reciprocally slid by a servo motor, and is connected to the spool so as to change the passage cross-sectional area in the spool chamber.

Of course, the electric actuator 71 is electrically connected to the controller 24 described later, and the form thereof is arbitrary as long as it can reciprocally slide the spool by the output current from the controller 24. It is also possible to use a motor or an electromagnetic coil as the electric actuator 71.

The throttle 18 is manufactured as a fixed throttle having a passage cross-sectional area narrower than that of the supply-side hydraulic pipe 62, and keeps the hydraulic pressure in the supply-side hydraulic pipe 62 on the upstream side at a high pressure equal to or higher than a predetermined value. High pressure oil can be taken out from the supply side hydraulic pipe 62 on the upstream side.

As described above, the cut delay correction hydraulic pipe 19 branches the other end into the cut delay correction hydraulic branch pipes 20 and 21, and the branch pipes 20 and 21 are corrected hydraulic ports 57, 21 of the control valve 13. It is connected corresponding to 58, and it is possible to directly supply the high-pressure pressure oil flowing through the supply-side hydraulic pipe 62 upstream of the throttle 18 to the reaction force chambers 46 and 47 of the control valve 13. .

The pair of cut-delay correction valves 22 and 23 are electromagnetic two-way control valves, which are arranged in the corresponding cut-delay correction hydraulic branch pipes 20 and 21, respectively, and are driven by an output current from a controller 24 described in detail later. , From the supply-side hydraulic pipe 62 upstream of the throttle 18 to the reaction force chambers 46, 47 of the control valve 13.
Controls the amount of pressure oil supplied directly to.

The controller 24 electrically connects the input side to the vehicle speed sensor 25 and the steering amount sensor 26, respectively, and further, the electric actuator 71 and the solenoid coil 72, of the reaction force adjusting valve 17 and the cut-off correction valves 22 and 23 thereof. The output side is electrically connected to 73, respectively, and the output currents for the reaction force adjusting valve 17 and the cut-delay correction valves 22 and 23 are determined according to the signals from the vehicle speed sensor 25 and the steering amount sensor 26. , Its output current to its electric actuator 71 and solenoid
The reaction force adjusting valve 17 is caused to flow through the coils 72, 73 to open and close, and at that time, the reaction force adjusting valve 17 changes the passage cross-sectional area and selectively cuts the delay adjustment valves 22, 23. The opening and closing correction valves 22 and 23 at that time are opened for a time determined according to the steering amount, that is, the rotation speed, the rotation direction and the rotation angle of the steering wheel.

Of course, the controller 24 has input and output circuits,
It is composed of a memory circuit, an arithmetic circuit, a control circuit and a power supply circuit, and the power supply circuit shares a battery (not shown) of the truck.

In particular, this controller 24 is associated with the truck by its control valve, which corresponds to the optimum value of the power cylinder pressure corresponding to the vehicle speed and the steering amount.
The ideal value of the reaction force pressure of 13 is input in advance, and it is calculated based on the signals from the vehicle speed sensor 25 and the steering amount sensor 26, and the calculated value and its optimum value are compared, and the reaction force adjustment valve Controls the output current flowing through the control valve 13, and adjusts the passage cross-sectional area of the reaction force adjusting valve 17 so that the reaction force pressure of the reaction force chambers 46 and 47 of the control valve 13 matches the ideal value that was input in advance. The power steering 10 can respond to the vehicle speed and the steering amount, and the controller 24 is associated with the truck and responds to the steering amount by reversing the control valve 13 thereof. When applying the correction hydraulic pressure to the force chambers 46, 47, an energization pattern for determining the energization time of the cut-off delay correction valves 22, 23 corresponding to the injection time of the correction oil pressure is input in advance. In response to the signal from the steering amount sensor 26, Stop delay compensation valve 2
At the same time as determining the output current that selectively flows in 2, 23, the energization time of the output current that flows in the cut-off correction valves 22 and 23 was determined in comparison with the energization pattern, and the energization time was determined in this way. However, the output current of the cut-off correction valve
This power steering for steering is made to selectively flow to the solenoid coils 72 and 73 of 22,23 and selectively open the cut-off correction valves 22 and 23 for the determined energization time.
10 reduces the response delay, suppresses the increase in the tire cutting angle and the yaw rate, and improves the maneuverability and stability.

As such, the controller 24 controls the power steering 10 so that the steering force adapted to the vehicle speed and the steering amount is obtained, and the cut-off delay is corrected.

The vehicle speed sensor 25 detects the truck and the traveling speed, and is arranged on the output shaft of a transmission (not shown) mounted on the truck.

The steering amount sensor 26 is a rotation sensor that detects the steering amount of the steering wheel, that is, the rotation speed, the rotation direction, and the rotation angle of the steering shaft. It is arranged around the shaft.

The vehicle speed sensor 25 and the steering amount sensor 26 described above.
Is, of course, electrically connected to the input circuit of the controller 24, and the output circuit of the controller 24 includes an electric actuator 71 of the reaction force adjusting valve 17 and solenoids of the cut-off correction valves 22 and 23. It is electrically connected to the coils 72 and 73.

Therefore, the reaction force control valve 17 and the cut-off delay correction valves 22 and 23 are
In accordance with signals from the vehicle speed sensor 25 and the steering amount sensor 26, the controller 24 changes the passage cross-sectional area, and the opening time is determined to selectively open and close the passage.

Next, the operation of the power steering 10 described above will be described with reference to the running state of the truck. Since the internal combustion engine is operating, the oil pump 12 is driven and The pressure oil discharged is
The flow control valve 14 adjusts the flow rate,
If the flow rate of the predetermined pressure oil is the same, it flows into the supply-side hydraulic pipe 62 and is sent to the pump port 41 of the control valve 13.

The pressure oil sent to the pump port 41 passes through the return-side hydraulic pipe 63 when the spool 40 is in the neutral position as shown in FIG. It is returned from 42 to its oil reservoir 15.

Also, at the same time, the controller 24 controls the vehicle speed sensor 25.
And a signal from the output amount sensor 26 to control the output current flowing through the electric actuator 71 of the reaction force adjusting valve 17 and to control the reaction force chamber of the control valve 13 according to the vehicle speed.
Adjusting the hydraulic pressure of 46, 47 to obtain a hydraulic reaction force that matches the vehicle speed, and the output current that selectively flows through the cut-off correction valves 22 and 23 are determined, and at the same time the energizing time of the output current is set. The correction pressure oil is selectively injected into the reaction force chambers 46 and 47 of the control valve 13 according to the steering operation.In other words, the correction pressure oil in the cutting direction is controlled when the steering wheel is turned. In addition to the valve 13, when the steering wheel is returned, a correction pressure oil in the returning direction is added to the control valve 13 to reduce the steering delay for steering, that is, the response delay for steering.

Therefore, a description will be given of the operation of correcting the delay time of the power steering 10 when the truck travels while being steered. By the way, as you can easily understand,
As shown in the steering force diagram of FIG. 2, the steering wheel operation is
Steered, that is, the steering wheel is continuously right-turned, then backed, then left-turned
Then, the case where the truck is driven on the road after being returned, subsequently right-turned, and steered to be returned will be described as an example.

First, when the steering wheel starts to cut to the right from the neutral state of the steering force line in FIG. 2,
The right turn steering is sensed by the steering amount sensor 26, converted into an electric signal by the steering amount sensor 26, and given to the controller 24.
The output current flowing through the cut-off correction valve 23 is determined in accordance with the electric signal, and at the same time, the energization time of the output current is determined in comparison with the energization pattern previously input, and the determined energization time is determined. The output current is passed through the solenoid coil 73 of the cut-off correction valve 23, and the cut-off correction valve 23 is opened.

Therefore, the high-pressure correction pressure oil is supplied from the supply-side hydraulic pipe 62 on the upstream side of the throttle 18 to the reaction force chamber 47 in the cutting direction of the control valve 13, and thus, at the start of turning the handle, A correction pressure oil in the cutting direction is added to the control valve 13, in other words,
At the beginning of turning the steering wheel, the correction hydraulic pressure in the cutting direction is applied to the control valve 13, so that the spool 40
1 is quickly slid to the right from the neutral position in FIG. 1 and its pump port 41 is
Is connected to its cylinder port 44 via the spool groove 55 of the spool 40, and its tank port 42 is connected to its cylinder port 45 via the spool groove 56 of the spool 40, and is discharged from the oil pump 12. The pressure oil is
It is sent to the cylinder chamber 34 of the power cylinder 11 via the communication passage 64, and the power cylinder body 30 starts to be moved to the right side in FIG. 1, and at the same time,
The pressure oil in the cylinder chamber 35 of the power cylinder 11 passes through the communication passage 66 and the return side hydraulic pipe 63, and
It begins to be returned to the reservoir 15. Of course, when the pressure oil is supplied in such a manner, a part of the pressure oil is also sent to the reaction force chamber 46 through the reaction force communication port 52 and the bore 50.

Moreover, even when the correction pressure oil is applied to the reaction force chamber 47 in the cutting direction of the control valve 13 as described above,
The steering wheel is further cut to the right, so the control valve 13 control
The valve spool 40 continues to be slid further to the right by a spool shaft 80 driven by its steering wheel through its steering shaft, steering gear box, pitman arm, and convening rod, The pump port 41 and the cylinder port 44 are communicated with each other via the spool groove 55 of its spool 40, opening the port opening progressively wider and, at the same time, its tank port 42.
And the cylinder port 45, which are communicated with each other through the spool groove 56 of the spool 40 while opening the port opening so as to gradually widen, and the pressure oil discharged from the oil pump 12 passes through the communication passage 64 thereof to Power cylinder
A large amount of power is being supplied to the cylinder chamber 34 of 11
The cylinder body 30 is further moved to the right side in FIG. 1, and at the same time, the pressure oil in the cylinder chamber 35 of the power cylinder 11 is transferred to the communication passage 66 and the return side hydraulic pipe.
A large amount of oil is returned to the oil reservoir 15 via 63.

When the energization time has passed, the cut-off correction valve 23 is closed by the controller 24, and the supply-side hydraulic pipe 62 upstream of the throttle 18 via the cut-delay correction hydraulic pipe 19 is provided.
The reaction chamber in the cutting direction of the control valve 13
Since the correction pressure oil supplied to 47 is stopped, its control valve spool 40 is shown in FIG.
The steering shaft, steering gear box, pitman arm, and spool shaft 80 driven by the steering wheel via the convening rod are moved in the direction to be subsequently slid to the right, With the movement of the spool 40, the power cylinder body of the power cylinder 11
30 is also expelled from the oil pump 12 and by the pressure oil supplied to the cylinder chamber 34, the first
In the figure, moved further to the right, its power cylinder 11 is contracted as a whole, and its front wheel axle (not shown) is connected to the king pin (not shown) via its link lever, drag link and knuckle arm. A front wheel, which is rotated around (not shown) and is rotatably supported on its front wheel shaft, is steered to the right.

As such, when its front wheels are steered to the right, its valve body 38 will move to its power cylinder body 30.
It is moved to the right along with the so-called movement
Backed up, the pump port 41 and cylinder port 44 are disconnected from each other.

Then, when the steering wheel is started to be returned toward the neutral position, the return steering is sensed by the steering amount sensor 26, which converts it into an electric signal and transmits it to the controller 24. Therefore, the controller 24 determines the output current flowing through the cut-off correction valve 22 according to the electric signal, and at the same time, determines the energization time of the output current by comparing with the energization pattern input in advance. The output current is passed through the solenoid coil 72 of the cut-off correction valve 22 for the determined energization time, and the cut-off correction valve 22 is opened.

Therefore, the high-pressure correction pressure oil is supplied from the supply-side hydraulic pipe 62 on the upstream side of the throttle to the reaction force chamber 46 in the return direction of the control valve 13, and in this way, from the start of the handle return to the return direction. The correction pressure oil is applied to the control valve 13, in other words, since the correction oil pressure in the returning direction is applied to the control valve 13 from the beginning of the handle return, the spool 40 is right-turned as described above. 1 from the position toward the neutral position of FIG. 1, the pump port 41 and the cylinder port 43 of the spool 40 are opened so as to gradually widen the port openings, and the spool port 55 and the cylinder port 43 of the cylinder port 43 are opened through the spool groove 55 of the spool 40. The tank port 42 and the cylinder
At the same time, the port 44 is opened so as to gradually widen the port opening and communicated with each other through the spool groove 56 of the spool 40, and the pressure oil discharged from the oil pump 12 is connected to the communication passages 65, 66. Is started to be sent to the cylinder chamber 35 of the power cylinder 11, and at the same time, the pressure oil in the cylinder chamber 34 of the power cylinder 11 passes through the communication passage 64 and the return side hydraulic pipe 63 to the oil reservoir. 15 and the power cylinder body 30 in its power cylinder 11 begins to be moved to the left in FIG.

Further, even when the correction pressure oil is added to the pressure chamber 46 in the return direction of the control valve 13 as described above, the steering wheel is further returned,
The control valve of that control valve 13
Spool 40 has its steering shaft, steering gear box, Pitman arm, and convening rod through its steering shaft.
Continued to slide further to the left on the wheel-driven spool shaft 30, its pump port 41 and cylinder port 43 open to each other through progressively widening port openings and through spool groove 54 of its spool 40 to each other. At the same time, the tank port 42 and the cylinder port 44 are communicated with each other through the spool groove 55 of the spool 40, with the port opening gradually widening, and discharged from the oil pump 12. The pressure oil that has flowed through the communication passages 65 and 66 passes through the power cylinder 1
A large amount of oil is supplied to the cylinder chamber 35 of the power cylinder 11, and its power cylinder body 30 is further moved to the left side in FIG. 1, and at the same time, the pressure oil in the cylinder chamber 34 of the power cylinder 11 is started. Starts to be returned to the oil reservoir 15 in a large amount via the communication passage 64 and the return hydraulic pipe 63.

The energization time at the time of returning the handle is set longer than that at the time of starting the turning of the handle, and after the passing of the energizing time, the delay delay correction valve 22 is closed by the controller 24 and the turning off correction valve 22 is turned off. Delay compensation hydraulic piping 1
The supply side hydraulic pipe 62 upstream of the throttle 18 via 9,20
Since the correction pressure oil supplied to the reaction force chamber 46 of the control valve 13 from the
The valve spool 40 is its steering shaft,
Steering gear box, pitman arm,
And a spool shaft 80 driven by its steering wheel through a convening rod
In other words, in other words, with only the steering force given by the steering wheel, it is further moved in the direction to be slid to the left and kept returned, and the power cylinder 11 is moved along with the movement of the spool 40. The power cylinder body 30 of is also exhaled from its oil pump 12,
Then, the pressure oil supplied to the cylinder chamber 35 moves the power cylinder 11 further to the left, the power cylinder 11 is extended, and the front wheel of the power cylinder 11 passes through the king lever through the link lever, the drag link, and the knuckle arm. The front wheel, which is rotated about the pin and is rotatably supported on its front wheel shaft, is returned to its straight-ahead condition.

At that time, since the steering wheel is also returned to the neutral position, the control valve 13
Is returned to the state shown in FIG. 1 and the supply and discharge of pressure oil to the power cylinder 11 is stopped.

Then, when the steering wheel so returned is continuously turned to the left from the neutral state of the steering force line of FIG. 2, in this case, since the steering direction is the same, the steering amount sensor The controller 24 receiving the electric signal from 26 does not apply the output current to the solenoid coils 72, 73 of the cut-off correction valves 22, 23.

Therefore, when the steering wheel is steered to the left, the cut-off delay correction valves 22 and 23 are closed, and the high-pressure correction pressure oil is supplied to the supply-side hydraulic pipe 62 upstream of the throttle 18. Neither the reaction force chambers 46, 47 of the control valve 13 is supplied from the control valve 13, and the control valve 13, that is, the control valve spool 40 is exclusively used for the steering shaft, the steering gear box, and the pitman. The arm and its steering through the convening rod
It is slid to the left only by the spool shaft 80 driven by the wheel, i.e., only by the steering force provided by its steering wheel, and as the spool 40 moves, its pump port 41 and cylinder port 43.
Are opened so as to gradually widen the port opening, and are communicated with each other through the spool groove 54 of the spool 40.
At the same time, its tank port 42 and cylinder port
The pressure oil discharged from the oil pump 12 is connected to each other through the spool groove 55 of the spool 40 by opening 44 so that the port opening gradually widens.
5, 66 are started to be sent to the cylinder chamber 35 of the power cylinder 11, and at the same time, the pressure oil in the cylinder chamber 34 of the power cylinder 11 is transferred to the communication passage 64 and the return side hydraulic pipe 63. Begins to be returned to the oil reservoir 15 via
Along with that, the power cylinder body 30 of the power cylinder 11 starts sliding to the left side in FIG. 1, and the power cylinder 11 starts to further extend.

As such, as the power cylinder 11 begins to extend further, the front wheel axle, via its link lever, drag link, and knuckle arm, begins to rotate counterclockwise about the king pin, The front wheel rotatably supported above begins to steer to the left.

Further, when the pressure oil discharged from the oil pump 12 starts to be supplied to the cylinder chamber 35 of the power cylinder 11, a part of the pressure oil is connected to the communication passages 64 and 65, the spool groove 56,
It is also sent to the reaction force chamber 47 via the reaction force communication port 53 and the bore 51.

Further, when the steering wheel is steered to the left, the spool 40 in the control valve 13 is further slid to the left side by the steering force given by the steering wheel, and the spool 40 moves with the movement of the spool 40. Its pump port 41 and cylinder
The ports 43 communicate with each other through their spool grooves 54, allowing the port openings to open wider, and
At the same time, its tank port 42 and cylinder port 44 allow the port opening to open wider,
The pressure oils communicated with each other through the spool groove 55 and discharged from the oil pump 12 are transferred to the communication passages 65, 66.
A large amount of oil is sent to the cylinder chamber 35 of the power cylinder 11 via the hydraulic cylinder, and at the same time, the pressure oil in the cylinder chamber 34 of the power cylinder 11 is transferred to the communication passage 64 and the return side hydraulic pipe.
A large amount is returned to the oil reservoir 15 via 63.

Accordingly, the power cylinder body 30 of the power cylinder 11 is moved further to the left in FIG. 1, that is, the power cylinder 11 is further extended as a whole, so that The front wheel axle is further rotated leftward about its king pin via its link lever, drag link, knuckle arm, and its front wheel rotatably supported on its front wheel axle is left. It is steered greatly in the direction.

Subsequently, when the steering wheel so steered to the left begins to be returned towards the neutral position, in other words when it is turned towards the neutral state of the steering force line of FIG. The steering is sensed by the steering amount sensor 26, converted into an electric signal by the steering amount sensor 26, and given to the controller 24, so that the controller 24 responds to the electric signal by the cut-delay correction valve. At the same time as determining the output current flowing through 23
The energization time of the output current is determined in comparison with the energization pattern input in advance, and the output current is passed through the solenoid coil 73 of the cut-off correction valve 23 for the determined energization time, and the cut-delay correction valve Open 23

Therefore, the high-pressure correction pressure oil is supplied from the supply-side hydraulic pipe 62 upstream of the throttle 18 to the control valve thereof.
13 is supplied to the reaction force chamber 47, and in this way, the correction pressure oil in the return direction is controlled from the beginning of the handle return.
Since the correction hydraulic pressure in the return direction is applied to the control valve 13 from the beginning of the handle return, the spool 40 is quickly slid to the right from the state shown in FIG. The pump
At the same time, the port 41 is connected to the cylinder port 44 via the spool groove 55 of the spool 40, and the tank port 42 is connected to the cylinder port 44 via the spool groove 56 of the spool 40.
The pressure oil discharged from the oil pump 12 to each of the ports 45 is sent to the cylinder chamber 34 of the power cylinder 11 via the communication passage 64, and the power cylinder body 30 is The pressure oil in the cylinder chamber 35 of the power cylinder 11 begins to be moved to the right in the direction viewed from the figure, and at the same time, the pressure oil in the cylinder chamber 35 of the power cylinder 11 passes through the communication passage 66 and the return side hydraulic pipe 63 of the oil reservoir 15 thereof. Began to be returned to
The power cylinder body 30 of the power cylinder 11 starts to move toward the state shown in FIG. 1, and the power cylinder 11 starts to contract as a whole.

And so, the correction pressure oil is
While being added to the reaction force chamber 47 of the valve 13, the steering wheel is further returned, so that the control valve spool 4 of the control valve 13 has its steering shaft, steering gear, Continued to slide further to the right with a spool shaft 80 driven by its steering wheel through a box, pitman, arm, and conventing rod, its pump port 41 and cylinder port 44 progressively opening the port opening. While opening to spread, they are communicated with each other through the spool groove 55 of the spool 40,
At the same time, the tank port 42 and the cylinder port 45 are communicated with each other through the spool groove 56 of the spool 40 while being opened so as to gradually widen the port opening, and discharged from the oil pump 12. The pressure oil is
A large amount starts to be supplied to the cylinder chamber 34 of the power cylinder 11 via the communication passage 64, and the power cylinder body 30 is further slid to the right side in FIG. A large amount of the pressure oil in the cylinder chamber 35 of the cylinder 11 is returned to the oil reservoir 15 via the communication passage 66 and the return hydraulic pipe 63. As such, since the pressure oil is supplied to and discharged from the power cylinder 11,
The power cylinder body 30 is moved so that it is closer to the state shown in FIG. 1, and the power cylinder 11 is generally contracted.

The energization time at the time of returning the steering wheel corresponds to the energization time at the time of returning the steering wheel described above, and when the energization time elapses, the cutoff delay correction valve 23 is closed by the controller 24, and the cutoff delay correction hydraulic pressure. The correction pressure oil supplied to the reaction force chamber 47 of the control valve 13 from the supply side hydraulic pipe 62 upstream of the throttle 18 via the pipes 19 and 21 is stopped, so that the control valve spool 40 Is its steering shaft, steering
Only the spool shaft 80 driven by the steering wheel via the gear box, the pitman arm and the conveniging rod, in other words, only the steering force provided by the steering wheel, , Is slidably returned to the neutral position shown in FIG. 1, and as the spool 40 moves, the pressure oil discharged from the oil pump 12 in the power cylinder 11 is supplied to the supply side hydraulic pressure. Piping 62 and communication passage
It is supplied to the cylinder chamber 34 via 64, and at the same time, the pressure oil in the cylinder chamber 35 is returned to the oil reservoir 15 via the communication passage 66 and the return side hydraulic pipe 63, so that the power cylinder 11 as a whole. 1 to the state shown in FIG. 1, and its front wheel axle is further rotated about its king pin via its link lever, drag link, knuckle arm, The front wheel rotatably supported on the front wheel shaft is returned to the straight traveling state.

In that case, the valve of the control valve 13
The body 38 is moved to the right along with the power cylinder body 30 of its power cylinder 11, so-called movement is fed back and its pump port 41 is disconnected from its cylinder port 44, and The supply and discharge of pressure oil to the power cylinder 11 is stopped.

During the subsequent steering, when the steering wheel is returned as described above, the correction pressure oil in the returning direction is applied to the control valve 13
Is added to

Therefore, this power steering shown in FIG.
10 yaw rate characteristic lines f ₁ and normal speed-sensitive power
Comparing with the steering yaw rate characteristic line f ₀ ,
In this power steering 10, the yaw rate amplitude is smaller than that of normal power steering, and the delay time l ₁ of this power steering 10 is smaller than that of normal power steering l _0. Becomes
As a result, it is understood that the turning delay is improved, the increase in the tire turning angle is suppressed, and the steerability and stability are improved.

Further, in the power steering 10, the correction pressure oil is injected into the reaction force chambers 46 and 47, so that the injection shock of the correction pressure oil is alleviated and the steering wheel becomes less sensitive.

Next, the operation of the power steering 10 according to the vehicle speed of the truck will be described.When the truck is running at a low speed now, the controller 24 inputs a signal from the vehicle speed sensor 25, Calculate according to the input signal, compare with the ideal pressure value of the reaction force input in advance,
The output signal, that is, the output current is determined, and the output current is passed to the electric actuator 71 of the reaction force adjusting valve 17, so that the electric actuator 71 is driven, and in the reaction force adjusting valve 17, the spool is Sliding into the spool chamber to widen the passage cross sectional area of the spool chamber.

Therefore, when the control valve spool 40 of the control valve 13 is slid to either one by steering, the pressure oil discharged from the oil pump 12 is moved according to the sliding direction of the spool 40. Is its power
Either one of the cylinder chambers 34, 35 of the cylinder 11, and
It is sent to either one of the reaction force chambers 46 and 47 of the control valve 13.

For example, when the spool 40 is slid to the right in FIG.
To the cylinder port 44, and its tank
Cylinder port with port 42 through its spool groove 56
The pressure oil discharged to each of the oil pumps 12 from each of the oil pumps 12 is sent to the cylinder chamber 34 of the power cylinder 11 through the communication passage 64, and the power cylinder body 30 of FIG. , The pressure oil in the cylinder chamber 35 of the power cylinder 11 is moved to the right,
And the oil reservoir 15 via the return hydraulic line 63.
Is returned to.

As such, when the pressure oil is supplied and discharged, a part of the pressure oil passes through the reaction force communication port 52 and the bore 50, and then the reaction force chamber.
Sent to 46.

The reaction force at the time of such steering is given by the hydraulic pressure in the reaction force chamber 46, but as described above, at the time of low speed traveling, since the passage cross-sectional area of the reaction force adjustment valve 17 is wide, The pressure oil in the reaction force chamber 46 passes through the reaction force adjusting passage 16 and flows into the other reaction force chamber 47 without being extremely throttled by the reaction force adjusting valve 17.

When the spool 40 is slid in the above-mentioned direction, the tank port 42 is communicated with the spool groove 56, and the pressure oil in the reaction force chamber 47 passes through the return side hydraulic pipe 63. It is returned to the oil reservoir 15.

Therefore, the pressure drop due to the reaction force adjusting valve 17 becomes small, the pressure difference between the left and right reaction force chambers 46, 47 becomes small, and the pressure oil in the reaction force chamber 46 is great for the sliding of the spool 40. It does not cause resistance, in other words, steering at low speed traveling is performed with a small operating force.

When the spool 40 of the control valve 13 is slid to the left side in FIG. 1, the pump port 41 is in the spool groove 54 and the tank
The pressure oil discharged from the oil pump 12 is connected to the spool grooves 55 of the ports 42, and the communication passages 65, 6
6 is sent to the cylinder chamber 35 of the power cylinder 11, the power cylinder body 30 is slid to the left side in FIG. 1, and the pressure oil in the cylinder chamber 34 of the power cylinder 11 is The oil is returned to the oil reservoir 15 via the communication passage 64 and the return hydraulic pipe 63.

Contrary to the above case, the pressure oil in the reaction force chamber 47 passes through the reaction force adjustment passage 16 and is sent to the reaction force chamber 46 without being extremely narrowed down by the reaction force adjustment valve 17. , The pressure oil in the reaction force chamber 46 is the bore 50, the reaction force communication port 52, the spool groove 55,
It is returned to the oil reservoir 15 via the tank port 42 and the return hydraulic line 63.

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 46, 47 becomes small, and the pressure oil in the reaction force chamber 47 becomes There is no great resistance to the sliding of the spool 40, and steering is performed with a small operating force.

Further, when the truck travels at high speed, the controller 24 inputs a signal from the vehicle speed sensor 25, calculates according to the input signal, and compares it with an ideal pressure value of a reaction force input in advance, The output current is determined, and the output current is passed through the electric actuator 71 of the reaction force adjusting valve 17.

Therefore, the electric actuator 71 is driven by the output current, and in the reaction force adjusting valve 17, the spool is slid into the spool chamber and the spool
The passage cross-sectional area of the chamber is adapted to the vehicle speed and narrowed.

As with the low-speed driving described above,
When the control valve spool 40 of the valve 13 is steered to slide on either side, the pressure oil is transferred to the power cylinder 11 according to the sliding direction of the spool 40.
Is sent to either one of the cylinder chambers 34, 35 of the cylinder, the piston 32 is slid, and part of the pressure oil is part of the pressure chamber.
Although it is sent to either one of 46 and 47, since the passage sectional area in the spool chamber of the reaction force adjusting valve 17 is narrowed,
The pressure drop due to the reaction force adjusting valve 17 becomes large, and the pressure difference between the left and right reaction force chambers 46, 47 becomes large. As a result, one of the pressure oils in the reaction force chambers 46, 47 becomes Great resistance to sliding.

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

Further, when the truck is stationary, the traveling speed is zero, so that the reaction force adjusting valve 17 widens the passage cross-sectional area to the maximum and the pressure difference between the reaction chambers 46 and 47 is increased. Becomes extremely small, and as a result, the stationary cutting is performed with a very small operating force.

Of course, the operation of the power steering 10 with respect to the vehicle speed described above is performed at the same time as the correction operation of the delay of the power steering 10 described above.

FIG. 3 shows correction pressure oil and yaw rate characteristics with respect to the steering force of another specific example of the power steering used in the vehicle of the present invention.

As can be understood from FIG. 3, this power steering is different from the power steering 10 in that the injection time of the correction pressure oil in the returning direction, which is added to the control valve when the steering wheel is returned. Changing. In other words, in this power steering, the controller inputs a signal from the steering amount sensor, determines the energizing time corresponding to the energizing pattern until the steering wheel is substantially returned, and the steering wheel returning is determined. The current is passed through the solenoid coil of the cut-off correction valve in the return direction for the duration of energization to open the cut-off correction valve in the return direction.
Then, the correction pressure oil is injected into the reaction force chamber in the return direction of the control valve. As such, in this power steering, the return pressure compensation oil is applied to the steering wheel return until the steering wheel is substantially returned, specifically, until the steering wheel is returned to the neutral position. Added to the valve.

As a result, as can be understood from the yaw rate characteristic line f _{2 of} FIG. 3, the yaw rate amplitude of this power steering and the cut-off delay l ₂ are
10 and those of normal power steering are smaller than f ₁ , f ₀ and l ₁ , l ₀ , the cut-off delay is improved,
The increase in the tire turning angle is further suppressed, and the steerability and stability are further improved.

Also, in this case, the correction pressure oil in the return direction is added to the control valve until the handle is returned from the position steered to the right to the neutral position, but in the return direction. Compensation pressure oil can also be added to the control valve until the beginning of its left steering, provided that the handle is returned to the neutral position and continuously steered to the left, in which case The steering will be smoother. Further, even in this power steering, the correction pressure oil is injected into the reaction force chamber of the control valve, so that the injection shock of the correction pressure oil is alleviated and the steering sensitivity is suppressed.

The power steering 10 previously described has been described as having a corrected pressure oil applied to its control valve 13, but the corrected pressure oil is applied to the power cylinder 11 thereof.
Can be added directly to. Then, in that case, compared with the case where the correction pressure oil is applied to the control valve 13, the injection shock of the correction pressure oil is further alleviated and the steering sensitivity is further suppressed.

Also, the power steering 10 described above was described as steering the front wheels of the truck,
If the rear axle is steered in the vehicle,
The power steering 10 is also applicable to the steering of the rear wheels that are swingably connected to both ends of the axle thereafter.
In this case, it is desirable to set the power steering for steering the front wheels so that they are synchronized in the opposite phase during low speed traveling and in the same phase during high speed traveling.

As is apparent from the specific embodiments of the present invention described above with reference to the drawings, those skilled in the art to which the present invention pertains have ordinary knowledge in that It is readily embodied in another embodiment that derives from the nature and substance of the invention and is objectively admitted to incorporate them. Of course, the subject matter of the present invention is commensurate with the subject of the invention and is essential for the establishment of the invention.

Benefits of the Invention As will be understood from the above, the power steering used in the vehicle of the present invention includes a power cylinder having a pair of cylinder chambers, an oil pump, a control valve having a pair of reaction chambers, and a flow. ·Control·
In a configuration in which a valve and an oil reservoir are configured in a hydraulic circuit for steering, a throttle is arranged in the hydraulic circuit on the supply side that connects the flow control valve to the control valve in the hydraulic circuit, and the delay adjustment is performed. The hydraulic pipe connects the upstream side of the throttle of the supply side hydraulic pipe to the pair of reaction force chambers of the control valve or the pair of cylinder chambers of the power cylinder, and the pair of cut-and-delay correction valves control the control. -A pair of reaction chambers of the valve or a pair of cylinder chambers of its power cylinder are arranged in the cut-off delay hydraulic pipe to correspond to them.
Then, the correction pressure oil can be injected into the reaction force chamber or the cylinder chamber, and the controller previously inputs the energization pattern that determines the energization time of the cut-off correction valve corresponding to the injection time of the correction pressure oil. Then, by inputting a signal from the steering amount sensor, the energization time is determined in comparison with the energization pattern, and at the beginning of turning the steering wheel, the current is supplied only for the determined energization time in the cutting delay correction valve in the cutting direction. Flow through the solenoid coil of the control valve to open the cut-off delay correction valve in the cutting direction, and the correction pressure oil is applied to the reaction force chamber in the cutting direction of the control valve or its power
It is injected into the cylinder chamber in the cutting direction of the cylinder, and at the beginning of the handle return, a current is passed through the solenoid coil of the return delay stop delay compensation valve for the determined energizing time, and the return delay stop delay compensation valve is supplied. Is opened and the correction pressure oil is injected into the reaction force chamber in the return direction of the control valve or the cylinder chamber in the return direction of the power cylinder. Therefore, the power steering used in the vehicle of the present invention is also , A power cylinder having a pair of cylinder chambers, an oil pump, a control valve having a pair of reaction chambers, a flow control valve,
And a configuration in which an oil reservoir is configured in a hydraulic circuit for steering, a throttle is arranged in the hydraulic circuit on the supply side that connects the flow control valve to the control valve in the hydraulic circuit, and the delay delay correction hydraulic pipe is provided. Connects the upstream side of the throttle of the supply side hydraulic pipe to the pair of reaction force chambers of the control valve or the pair of cylinder chambers of the power cylinder, and the pair of cut-and-delay correction valves are connected to the control valve. Corresponding to the pair of reaction chambers of the power cylinder or the pair of cylinder chambers of the power cylinder, and arranged in the cut-off delay hydraulic pipe, and
The correction pressure oil can be injected into the reaction force chamber or the cylinder chamber, and the controller previously inputs an energization pattern that determines the energization time of the cut-off correction valve corresponding to the injection time of the correction pressure oil, Then, by inputting a signal from the steering amount sensor, the energization time is determined in comparison with the energization pattern, and at the beginning of turning the steering wheel, the current is supplied for the determined energization time to the solenoid of the cut-delay correction valve in the cutting direction. Flowing through a coil to open the cut-delay correction valve in the cutting direction, and injecting the correction pressure oil into the reaction force chamber in the cutting direction of the control valve or the cylinder chamber in the cutting direction of the power cylinder, and When the handle is returned, the solenoid of the cut-off correction valve in the return direction is supplied with current for the determined energizing time corresponding to the time when the handle is substantially returned. The present invention is adapted to flow through the coil to open the return delay compensating valve and inject the correction pressure oil into the reaction chamber of the control valve in the returning direction or the cylinder chamber of the power cylinder in the returning direction. In the power steering used in other vehicles, the shock of injection of correction pressure oil is mitigated to prevent the steering wheel from becoming hypersensitive, and the response delay of the vehicle behavior to the steering wheel operation is reduced, and the steering angle to the steering wheel angle is reduced. A speed-sensitive characteristic is obtained in which an increase in tire turning angle and yaw rate is suppressed and maneuverability and stability are improved, and as a result, it is very useful and practical for a vehicle.

[Brief description of drawings]

FIG. 1 is a schematic view showing a specific example of power steering used in a vehicle of the present invention applied to a truck,
FIG. 2 is a characteristic diagram of corrected pressure oil and yaw rate with respect to the steering force of the power steering shown in FIG. 1, and FIG. 3 is another specific example of the power steering used in the vehicle of the present invention. FIG. 6 is a characteristic diagram of corrected pressure oil and yaw rate with respect to the steering force of FIG. 11 …… power cylinder, 12 …… oil pump, 13…
… Control valve, 14 …… Free control valve, 15 …… Oil reservoir, 16 …… Reaction force adjusting passageway, 17 …… Reaction force adjusting valve, 18 …… Throttle, 19 …… Delay delay compensation hydraulic piping , 22,23 …… Delay delay correction valve, 24 …… Controller, 25 …… Vehicle speed sensor, 26 …… Steering amount sensor, 62 …… Supply side hydraulic piping, 63 …… Return side hydraulic piping.

Claims (2)

(57) [Claims] 1. A power cylinder having a pair of cylinder chambers, an oil pump, a control valve having a pair of reaction chambers, a flow control valve, and an oil reservoir which are configured in a hydraulic circuit for steering. In the hydraulic circuit, the throttle is arranged in the supply side hydraulic pipe connecting the flow control valve to the control valve, and the cut-off delay correction hydraulic pipe is arranged in the upstream side of the throttle of the supply side hydraulic pipe. The pair of reaction delay chambers of the control valve or the pair of reaction chambers of the power cylinder are connected to the pair of reaction chambers of the control valve or the pair of cylinder chambers of the power cylinder. Corresponding to the cylinder chamber, it is arranged in the delay delay compensating hydraulic pipe, and the compensating pressure oil is fed to the reaction chamber. Alternatively, the controller can pre-enter an energization pattern that determines the energization time of the cut-off delay correction valve corresponding to the injection time of the correction pressure oil, and the signal from the steering amount sensor. Enter, determine the energization time in comparison with the energization pattern, and
At the beginning of turning the steering wheel, a current is passed through the solenoid coil of the cut-delay compensation valve in the cutting direction for the determined energization time to open the cut-delay compensation valve in the cutting direction, and the compensation pressure oil is supplied to the control valve. Is injected into the reaction force chamber in the cutting direction or the cylinder chamber in the cutting direction of the power cylinder, and at the beginning of the handle return, current is supplied for the determined energizing time for the solenoid coil of the cut-delay compensation valve in the returning direction. A vehicle characterized by flowing into the return direction of the control valve to open the cut-off delay valve, and then injecting the corrected pressure oil into the reaction force chamber of the control valve in the return direction or into the cylinder chamber of the power cylinder in the return direction. Power steering used for. 2. A hydraulic circuit comprising a power cylinder having a pair of cylinder chambers, an oil pump, a control valve having a pair of reaction force chambers, a flow control valve, and an oil reservoir for steering. In the hydraulic circuit, the throttle is arranged in the supply side hydraulic pipe connecting the flow control valve to the control valve, and the cut-off delay correction hydraulic pipe is arranged in the upstream side of the throttle of the supply side hydraulic pipe. The pair of reaction delay chambers of the control valve or the pair of reaction chambers of the power cylinder are connected to the pair of reaction chambers of the control valve or the pair of cylinder chambers of the power cylinder. Reacted by the cylinder chamber, it is placed in the delay delay compensating hydraulic pipe, and the compensating pressure oil is fed into the reaction force chamber. Alternatively, the controller can pre-enter an energization pattern that determines the energization time of the cut-off delay correction valve corresponding to the injection time of the correction pressure oil, and the signal from the steering amount sensor. Enter, determine the energization time in comparison with the energization pattern, and
At the beginning of turning the steering wheel, a current is passed through the solenoid coil of the cut-delay compensation valve in the cutting direction for the determined energization time to open the cut-delay compensation valve in the cutting direction, and the compensation pressure oil is supplied to the control valve. Injection into the reaction chamber in the cutting direction or the cylinder chamber in the cutting direction of the power cylinder, and when returning the handle, the current is returned for the determined energizing time corresponding to substantially returning the handle. Flow to the solenoid coil of the valve in the direction of opening and closing to open the valve in the direction of returning to open the valve, and to apply the correction pressure oil to the reaction chamber in the returning direction of the control valve or in the returning direction of the power cylinder. Power steering used in vehicles characterized by injecting into the cylinder chamber.