JPH0587428B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to power steering systems used in vehicles, particularly speed and road friction sensitive systems used in vehicles with computer-controlled anti-skid brakes. Regarding type power steering.

BACKGROUND TECHNOLOGY In general, speed-sensitive power steering has become popular in automobiles, but with this type of power steering, the road surface tends to become slippery at curved parts of the road, such as when the road is icy. When the car entered the slippery road, the driver turned the steering wheel too much, risking the car spinning out and overturning.

Furthermore, when speed-sensitive power steering of this kind is used in trucks, buses, etc., the steering force changes depending on the loaded weight, resulting in differences in operational feel, maneuverability, and stability.

Further, Japanese Patent Application Laid-open No. 118574/1983 discloses a power steering system for use in vehicles, which consists of a pair of auxiliary reaction chambers separated from a pair of reaction chambers, and a control chamber.・A throttle disposed upstream of the valve, an auxiliary reaction force control passage connecting the upstream side of the throttle to the pair of auxiliary reaction force chambers, and an auxiliary reaction force control valve disposed in the auxiliary reaction force control passage. and adjusting the amount of pressure oil sent to the pair of auxiliary reaction chambers with the auxiliary reaction force control valve to prevent delay in operation, and
This is where we try to obtain the appropriate reaction force.

However, since the pressure oil supplied to the pair of auxiliary reaction force chambers is guided from the upstream side of the restriction, there is a possibility that the pressure fluctuations in the pressure oil may prevent the delay in the power steering operation from being properly avoided. There is. In addition, since the pair of auxiliary reaction force chambers are separated from the pair of reaction force chambers, the control and
The valve structure becomes complicated.

Purpose/Problem of the Invention Purpose of this invention. The challenge is to obtain an optimal steering force that corresponds to the road friction value (road surface sliding friction coefficient μ) during braking without being affected by the loaded weight, that is, to obtain an antiskid that has road friction sensitivity characteristics and load sensitivity characteristics. - Provides power steering used in vehicles equipped with brakes.

Summary of the invention related to the purpose/problem: Contents of the claimed invention The above-mentioned purpose. In relation to the problem, the power steering used in the vehicle of the present invention includes a hydraulic circuit including a power cylinder having a pair of cylinder chambers, an oil pump, and a control valve having a pair of reaction force chambers. , which steers a pair of front wheel axles swingably connected to both ends of the front axle of a vehicle equipped with anti-skid brakes, and the compensating hydraulic piping controls and controls the pair of front wheel axles.
On the upstream side of the valve, it is branched from the supply side hydraulic piping of the hydraulic circuit, an accumulator is connected to the compensation hydraulic piping, and the compensation pressure control valve can reciprocate in the valve body and the spool bore of the valve body. and a back pressure chamber that causes pressure oil led from the accumulator to act on the spool against the pressure setting spring; - downstream of the branch point of the compensating hydraulic line, so as to supply and store a portion of the pressure oil flowing from the pump to the control valve in the accumulator and to maintain the pressure in the accumulator at the set value; A pair of reaction force compensation pipes are disposed upstream of the accumulator across the supply side hydraulic piping and the compensation hydraulic piping, and a pair of reaction force compensation piping is connected between the reaction chamber of the control valve and the accumulator. A compensation valve is placed in the reaction force compensation piping, and the controller inputs rotation difference information between the driving wheel and driven wheel during normal driving and tire slip rate information during braking from the computer of the anti-skid brake. Then, based on that information, a road surface friction value is calculated, and according to the calculated value and a signal from a pair of pressure sensors connected correspondingly to the steering amount sensor or the reaction force chamber of the control valve, The reaction force compensation valve is configured to selectively open and close, and when braking, the reaction force compensation valve is selectively opened and closed with an output current determined according to the calculated value, and the reaction force chamber is Pressure oil is selectively supplied to the accumulator to obtain the optimum steering force corresponding to the road friction value.

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

The figure shows an anti-skid brake (not shown)
10 schematically shows ten specific examples of power steering used in a vehicle according to the present invention, which is applied to a truck equipped with a power steering system according to the present invention.

This power steering 10 is used to steer a pair of front wheel axles that are swingably connected to both ends of the front axle of the truck, and to steer front wheels that are each rotatably supported by the front wheel axles. , embodied in a linkage type, including a knuckle arm (not shown), a drag link (not shown),
link lever (not shown), compensating rod (not shown), pitman arm (not shown), steering gear box (not shown), steering shaft (not shown),
Power cylinder 1 with a steering wheel (not shown) and a pair of cylinder chambers 34, 35
1, oil pump 12, pair of reaction chambers 46, 4
Control valve 13 with 7, flow
Control valve 14, oil reservoir 1
5. Reaction force adjustment passage 1 that communicates the pair of reaction force chambers 46 and 47 of the control valve 13 with each other.
6, a counter-adjustment valve 17 that adjusts the reaction pressure in the reaction chambers 46, 47, a compensation hydraulic piping 18, an accumulator 19, a compensation pressure control valve 20, a pair of reaction force compensation piping 21, 22, a pair of reaction force compensation Valves 23 and 24, a pair of pressure sensors 25 and 26, and their anti-skid
The controller 27 includes a controller 27, a vehicle speed sensor 28, and a steering amount sensor 29 that also communicate data with the brake computer 100. tire·
Slip rate information is input from the computer of the anti-skid brake, a road friction value is calculated based on the information, and when braking, the output current determined by the calculated value is applied to the reaction force compensation valves 23 and 24.
The reaction force compensation valves 23 and 24 are selectively opened and closed, and the pressure oil of the accumulator 19 is selectively supplied to the reaction force chambers 46 and 47 according to the signal from the steering amount sensor 29. The optimum steering force corresponding to the road friction value can be obtained. It is equipped with so-called road surface friction sensitivity characteristics and load sensitivity characteristics,
In addition, during normal driving, the controller 27 generates a reaction force corresponding to the sliding friction coefficient μ of the road surface and corresponding to the steering load (steering resistance) determined by the product of the sliding friction coefficient μ of the road surface and the load. The pressure sensors 25, 26 sense the oil pressure in the chambers 46, 47 and also sense the oil pressure in the reaction chambers 46, 47 corresponding to the loaded weight associated with the steering load (steering resistance), and the pressure sensors 25, 26 sense the vehicle speed. The vehicle speed sensor 28 detects the vehicle speed, and the pressure sensor 2 detects the oil pressure in the reaction force chambers 46 and 47 corresponding to the lateral acceleration.
5, 26, calculates based on the input signal, determines the output current flowing to the reaction force adjustment valve 17 and the reaction force compensation valve 23, 24, and uses the output current to adjust the reaction force adjustment valve 17. The output current is selectively applied to the reaction force compensation valves 23 and 24 according to the signal from the steering amount sensor 29, and the reaction force compensation valves 23 and 24 are selectively opened and closed. , the pressure oil of the accumulator 19 is selectively supplied to the reaction force chambers 46 and 47, and the optimum steering force corresponding to the sliding friction coefficient μ of the road surface, the loaded weight, the vehicle speed, and the lateral acceleration can be obtained. So-called road surface friction sensitivity characteristics, load sensitivity characteristics, lateral acceleration sensitivity characteristics,
and speed-sensitive characteristics.

As such, its power steering 10
The power cylinder 11 consists of a link mechanism and a hydraulic circuit.The hydraulic circuit consists of a part composed of a link mechanism and a hydraulic circuit. A power cylinder body incorporating 13 valve bodies 38 and forming a cylinder bore 31 communicating with oil ports 36, 37 connected to power cylinder ports 43, 44, 45 of the control valve 13. 30, and a pair of cylinder chambers 34, 35 are formed in the cylinder bore 31, and a pair of cylinder chambers 34, 35 are fitted in the cylinder bore 31 so as to be reciprocally slidable and are connected to the oil ports 36, 37 correspondingly. A power piston 32 and a piston whose one end is fixed to the power piston 32 and which extends outside the power cylinder body 30 so that the other end can be taken in and out.
The power cylinder body 30 is connected to the link lever and the piston is connected to the power cylinder body 30. Rods 33 are each rotatably connected to a chassis frame (not shown).

The power cylinder 11 also has an oil port 36 in its cylinder chamber 34 and a power cylinder port 4 in its control valve 13.
3 and 45, and a communication passage 66 that communicates between the oil port 37 of the cylinder chamber 35 and the power cylinder port 44 of the control valve 13.

Further, the power cylinder 11 is provided with correction hydraulic ports 38, 39 opened corresponding to the cylinder chambers 34, 35.

In the power cylinder 11 configured in this way, the movement of the power piston 32 becomes the movement of the power cylinder body 30 and piston rod 33, and the link lever,
It is transmitted via the drag link and the knuckle arm to the front wheels, so that the power cylinder 11 steers the front wheels.

The oil pump 12 is driven by an internal combustion engine (not shown) mounted on the truck and is connected to a pump port 41 of the control valve 13 to supply pressurized oil to the power cylinder 11. It is arranged in the supply hydraulic pipe 62 of the hydraulic circuit that connects the oil reservoir 15 to the oil reservoir 15, and sucks up the oil in the oil reservoir 15, pressurizes it, and generates a pressure oil approximately proportional to the rotational speed of the internal combustion engine. This ensures that the discharge amount can be obtained.
Of course, the oil pump 12 is manufactured to have a similar structure to the oil pump used in existing power steering systems, and its explanation will be omitted.

The control valve 13 is configured as a hydraulic reaction type spool valve, and its power
It is incorporated into the power cylinder body 30 of the cylinder 11 and connects the spool shaft 92 to its compensating rod, its pitman arm, steering gear box,
and via the steering shaft, the valve is operated by the steering wheel, and
In the hydraulic circuit, piping connecting the oil pump 12 and oil reservoir 15 to the power cylinder 11, that is, the supply hydraulic piping 62, the return hydraulic piping 63, and the communication passages 64, 65, 66 directionally controlling the pressure oil discharged from the oil pump 12 arranged and supplied to the power cylinder 11, and directionally controlling the pressure oil worked in the power cylinder 11,
The pressure oil is returned to the oil reservoir 15 on the suction side of the oil pump 12.

The control valve 13 includes a valve body 38 and a control valve spool 40 slidably disposed in a spool bore 41 of the valve body 38, the control valve spool 40 being reciprocally slidable in a spool bore 41 of the valve body 38. Its spool shaft 92, compensating rod, pittman arm, steering gear
box, and its spool at its steering wheel via the steering shaft.
The pressure oil that slides reciprocatingly within the bore 39 and flows into the pair of cylinder chambers 34 and 35 of the power cylinder 11 is switched, and along with the switching operation, the oil is transferred from the cylinder chambers 34 and 35 to the oil reservoir 1.
Control the direction of the pressure oil that is returned to 5.

The valve body 38 has a spool bore 39 formed therein having a predetermined inner diameter and length, and a spool bore 39 formed therein at a predetermined distance on one side (the upper side in the figure). three power cylinders connected to the spool bore 39 thereof, forming a pump port 41 and a tank port 42 connected to the spool bore 39 of the - Ports 43, 44, 45 are formed.

The pump port 41 is connected to the supply hydraulic piping 6
2 to the discharge side of the oil pump 12, and the tank port 42 is connected to the oil reservoir 15 via the return hydraulic line 63, and the power The cylinder ports 43, 44, 45 are connected to the communication path 6.
4, 65, and 66 to the cylinder chambers 34, 35 of the power cylinder 11.

Additionally, the valve body 38 has a control valve within the spool bore 39.
A pair of reaction ports 48, 49 are formed which are used to communicate reaction chambers 46, 47 formed on opposite sides of the valve spool 40, respectively.

This control valve spool 40 is
It is provided with bores 50 and 51 opened on both end faces, and is arranged to be able to reciprocate and slide in the spool bore 39,
As such, when fitted into the spool bore 39, the bores 50, 51 define a pair of reaction chambers formed within the spool bore 39 on opposite sides of the control valve spool 40. Increase the volumes of 46 and 47.

Also, this control valve spool 4
0 reciprocates within its spool bore 39, depending on its sliding direction, its reaction chambers 46, 4
7 is provided with a pair of reaction force communication ports 52 and 53 for supplying pressure oil.

In particular, its control valve spool 4
0 regarding its reaction force communication ports 52 and 53,
Spool grooves 54, 5 spaced apart from each other in the axial direction
5 and 56 are formed on the outer peripheral surface.

Of course, the spool grooves 55, 56 have reaction force communication ports 52, which communicate with the reaction force chambers 46, 47.
53 are correspondingly opened so that the reaction communication ports 52, 53 are connected to the spool grooves 55, 53 in the spool bore 39 as the control valve spool 40 moves.
56 connects the power cylinder ports 44, 45 to its reaction chambers 46, 47, and its spool groove 54 connects the pump ports 41, 45 to its reaction chambers 46, 47.
to power cylinder port 43.

Further, the control valve spool 40 extends through the valve body 38 to be slid back and forth into the spool bore 39 in response to steering operation.
Spool shaft 92 extended into bore 39
Approximately the center of the spool (spool center) is connected to the tip of the spool. Of course, the spool shaft 92 has its rear end connected to its compensating
Connected to rod.

So configured, the supply side hydraulic piping 62, the return side hydraulic piping 63, and the communication path 6
Its controls located at 4, 65, and 66
The valve 13 also has compensating hydraulic ports 57, 58 opened in its valve body 38 corresponding to the reaction chambers 46, 47 thereof.

The flow control valve 14 provides control and control to the oil pump 12 and oil reservoir 15 in the hydraulic circuit.
It is arranged in the hydraulic piping that connects the valve 13, that is, the supply hydraulic piping 62 and the return hydraulic piping 63.

The flow control valve 14 is connected to a pump port 59 connected to the discharge side of the oil pump 12, and the control valve 13
a casing having a control valve port 60 connected to the pump port 43 side of the oil pump 12 and a return port 61 connected to the suction side of the oil pump 12; oil return
The flow rate of the pressure oil sent to the pump port 59 is adjusted to a predetermined flow rate by controlling the control valve and the control spool.
The excess flow of pressure oil is returned to the oil reservoir 15 from the return port 61 via the control valve bypass 67.

Of course, the flow control valve 14
The valve is manufactured to have a similar structure to the flow control valve used in existing power steering systems, so a detailed explanation of its structure will be omitted.

The reaction force adjustment passage 16 has one end connected to the reaction force port 4.
8, connect the other end to the reaction force port 49,
The reaction force chambers 46 and 47 are connected to each other, and the control valve 13 is connected to the reaction force chambers 46 and 47.
In response to the movement of the valve spool 40, the reaction force chamber 4
6, 47 to allow pressure oil to move.

The reaction force adjustment valve 17 is connected to the reaction force adjustment passage 16.
The amount of pressure oil flowing between the reaction force chambers 46 and 47 is adjusted, and the pressure within these reaction force chambers 46 and 47 is adjusted.

The reaction force regulating valve 17 has a valve body 68 having a spool chamber (not shown) and a pair of ports 69, 70 in communication with the spool chamber, and slides reciprocally within the spool chamber. The spool is arranged such that the spool is movably arranged and changes the cross-sectional area of the passage within the spool chamber in response to the reciprocating movement of the spool.

Therefore, the flow rate of the pressure oil flowing between the ports 69 and 70 is adjusted according to the reciprocating movement of the spool. In other words, the pressure in the reaction chambers 46 and 47 of the control valve 14 is adjusted. Adjustments are made.

Of course, the reaction force adjustment valve 17 can have any shape as long as it can adjust the flow rate of the pressure oil flowing between the pair of ports 69 and 70. For example, it can be configured as a rotary type. be.

The reaction force adjustment valve 17 is operated by an electric actuator 7
It is opened and closed by 1. That is, the electric actuator 71 is a servo motor that reciprocates the spool of the reaction force regulating valve 17 to change the cross-sectional area of the passage within the spool chamber.
connected to that spool.

Of course, the electric actuator 71 can have any form as long as it is electrically connected to a controller 27, which will be described later, and causes the spool to reciprocate by the output current from the controller 27. For example, It is also possible to use a stepping motor or an electromagnetic coil as the electric actuator 71.

The compensation hydraulic line 18 is branched from the hydraulic line, ie, the supply hydraulic line 62, between the flow control valve 14 and the control valve 13 in the hydraulic circuit.

The accumulator 19 is connected to the compensating hydraulic line 18 and discharged from the oil pump 12 and the flow control valve 14
A portion of the pressure oil flowing into the supply side hydraulic piping 62 is stored. The pressure of the stored pressure oil is 15
It is set at ~20Kgf/ ^cm2 .

The compensation pressure control valve 20 has a valve body 7
2. Spool bore 7 of the valve body 72
3, and a pressure setting spring 75 acting on the spool 74.
Pressure oil led from 9 is connected to the pressure setting spring 7
5 and a back pressure chamber 76 acting on the spool 74 against the flow control valve 14, and a portion of the pressure oil discharged from the oil pump 12 and flowing through the flow control valve 14 to the control valve 13. is supplied to the accumulator 19 for storage, and the accumulator 1 is also connected downstream of the branch point of the compensating hydraulic piping 18 so as to maintain the pressure of the accumulator 19 at the set value.
It is disposed upstream of the supply hydraulic pipe 62 and the compensation hydraulic pipe 18 upstream of the hydraulic pressure pipe 9 .

Of course, the compensating pressure control valve 20 depends on the pressure of the accumulator 19 and the pressure setting spring 7.
The spool valve is embodied in a spool valve which is operated in a switched manner in force balance and unbalance with 5.

The compensation pressure control valve 20 so configured
Now, the valve body 72 has a spool bore 73 formed therein, and one end of the spool bore 73 is provided with a spool 74 that is reciprocally slidably fitted into the spool bore 73. A back pressure chamber 76 and a spring chamber 77 are formed at the other end of the spool bore 73, respectively.

Further, the valve body 72 is arranged at a predetermined distance on one side (the upper side in the figure).
The main pump connected to that spool bore 73
A port 78 and an auxiliary pump port 79 are formed, with a control valve port 80 and an accumulator port 81 on the other side (lower side in the figure) corresponding to the main and auxiliary pump ports 78, 79. a backpressure lead port 8 formed therein and further communicated with the backpressure chamber 76;
2 is formed.

Its main pump port 78 and control valve port 80 connect its supply hydraulic line 6
2 and its auxiliary pump port 7
9 and the accumulator port 81 are connected to its compensation hydraulic line 18.

The back pressure lead port 82 is connected to the compensating hydraulic pressure pipe 18 on the side of the accumulator 19 through a back pressure lead pipe 83, so that the pressure oil of the accumulator 19 can be led to the back pressure chamber 76.

Further, the valve body 72 has predetermined lands 85, 86 formed on the spool 74,
87, at its main pump port 78 and control valve port 80;
A ring groove 84 is formed on the inner peripheral surface of the spool bore 73.
is formed.

The spool 74 forms lands 85 , 86 , 87 , 88 at predetermined intervals in the axial direction, and the pressure in the back pressure chamber 76 and the force of the pressure setting spring 75 are balanced and unbalanced. spool·
It is slid back and forth within bore 73 to open and close its compensation pump port 79 and accumulator port 81.

The pressure setting spring 75 is connected to the valve.
The spool 74 is located in a spring chamber 77 formed in the body 72, and when the pressure in the back pressure chamber 76 is lower than a set value, the spool 74 to open its auxiliary pump port 79 and accumulator port 81.

A pair of reaction force compensation piping 21, 22 connects the accumulator 19 to compensation hydraulic ports 57, 58 formed in the valve body 38 of the control valve 13, and connects the reaction force chamber 46, 47 as its accumulator 1
9 so that the pressure oil stored in the accumulator 19 can be directly supplied to the reaction chambers 46 and 47.

In this way, the reaction force compensation pipes 21 and 22 are
Since the reaction force chambers 46 and 47 of the control valve 13 are connected to the accumulator 19, the accumulator 19 is made small.

The pair of reaction force compensation valves 23 and 24 are electromagnetic two-way control valves that are disposed in the corresponding reaction force compensation piping 21 and 22, and are opened and closed by output current from a controller 27, which will be described in detail later. from the reaction force chamber 46 of the control valve 13,
Controls the amount of pressure oil directly supplied to 47.

The pair of pressure sensors 25 and 26 have a structure that converts pressure into an electrical signal as usual, and the reaction force chamber 4 of the control valve 13
6, 47, arranged in the reaction force adjustment passage 16 on both sides of the reaction force adjustment valve 17,
When the truck runs normally, the oil pressure in the reaction chambers 46 and 47 corresponds to the sliding friction coefficient μ of the road surface and corresponds to the steering load (steering resistance) determined by the product of the sliding friction coefficient μ of the road surface and the load. The hydraulic pressure in the reaction force chambers 46, 47 corresponding to the loaded weight related to the steering load (steering resistance), and the hydraulic pressure in the reaction force chambers 46, 47 corresponding to the lateral acceleration of the truck is sensed. is converted into an electric signal and given to the controller 27 to enable the controller 27 to control the current flowing through the reaction force adjustment valve 17 and the reaction force compensation valves 23 and 24. The hydraulic pressure in the reaction force chambers 46 and 47 adjusted by the reaction force adjustment valve 17 is sensed, converted into an electric signal, and applied to the controller 27.
The controller 27 controls the reaction force adjustment valve 17 and feeds the oil pressure in the reaction force chambers 46 and 47.
Enable back control. Of course, that pressure sensor 2
5, 26 may be arranged directly in the corresponding reaction force chambers 46, 47.

The controller 27 controls the pressure sensor 2
5, 26, vehicle speed sensor 28, steering amount sensor 29,
The input side is electrically connected to the computer 30 of the anti-skid brake of the truck, and the electric actuator 71 and solenoid coils 90, 91 of the reaction force adjustment valve 17 and reaction force compensation valves 23, 24 are electrically connected. The output sides are electrically connected, the output current for the reaction force adjustment valve 17 and the reaction force compensation valves 23 and 24 is determined, and the output current is applied to the electric actuator 71.
and the solenoid coils 90 and 91 to open and close the reaction force adjustment valve 17, that is, change the passage cross-sectional area of the reaction force adjustment valve 17, and selectively open and close the reaction force compensation valves 23 and 24. Open and close. Of course, the controller 27 is comprised of an input and output circuit, a memory circuit, an arithmetic circuit, a control circuit, and a power supply circuit, and the power supply circuit shares the battery (not shown) of the truck.

More specifically, for that track during braking, the controller 27 determines, in relation to that track, an optimum power cylinder pressure corresponding to the road friction value (road surface sliding friction coefficient μ) during braking. A braking pattern with set values has been input in advance,
and electrically connected to the anti-skid brake computer 100 of the truck,
The computer 100 is enabled for data communication, inputs rotation difference information between the driving wheel and driven wheel during normal driving and tire slip rate information during braking from the computer 100, and calculates a road surface friction value.
The calculated value and the braking pattern are compared to determine the output current flowing to the reaction force compensation valves 23 and 24, and at the same time, the reaction force is compensated according to the signal from the steering amount sensor 29. Opening and closing of the valves 23 and 24 are selected, and the output current is selectively passed through the solenoid coils 90 and 91, and the reaction force compensation valve 2 is
3 and 24 are selectively opened and closed to selectively supply pressure oil from the accumulator 19 to the reaction force chambers 46 and 47 of the control valve 13, thereby increasing the steering force when braking is performed on a road surface with a small friction value. Make it heavier and prevent the truck from spinning. A steering force related to the so-called road friction value can be obtained, and safety during braking can be ensured. Of course, the reaction force compensation valve 23,
24, it is also possible to use the signals from the pressure sensors 25 and 26 instead of the signal from the steering amount sensor 29.

Also, for the track during normal driving,
First, the controller 27 has input in advance the optimum value of the power cylinder pressure corresponding to the vehicle speed and the amount of steering (steering wheel angle) in relation to the truck, and the optimum value of the power cylinder pressure corresponding to the power cylinder pressure is inputted in advance. Reaction force chamber 4 of its control valve 13
The pressure sensor 25 detects the oil pressure of 6,47,
The solenoid coils 90 and 91 of the reaction force compensation valves 23 and 24 are calculated based on the signals from the vehicle speed sensor 26 and the steering amount sensor 29, and the calculated value and the optimum value are compared. The reaction force compensating valves 23 and 24 are selectively opened and closed so that the oil pressure in the reaction chambers 46 and 47 matches the optimal value inputted in advance, and the pressure oil in the accumulator 19 is The reaction force chambers 46 and 47 of the control valve 13 are selectively supplied with the reaction force, thereby making it possible to respond to changes in the lateral acceleration of the truck.

The controller 27 also has the ideal value of reaction pressure corresponding to the vehicle speed and steering amount (steering wheel angle) inputted in advance in relation to the truck, and the pressure sensors 25, 26, the vehicle speed sensor 28, and the steering Calculate based on the signal from the amount sensor 29,
The calculated value and the ideal value are compared, and the output current flowing through the reaction force adjustment valve 17 is controlled so that the reaction pressure in the reaction force chambers 46 and 47 matches the ideal value input in advance. The opening degree of the reaction force adjustment valve 17 is adjusted to correspond to the vehicle speed and the amount of steering.

Further, the controller 27 has previously input an ideal value of reaction pressure corresponding to the steering load (steering resistance) determined by the product of the road surface sliding friction coefficient μ and the load in relation to the truck. It calculates based on the signals from the sensors 25, 26 and the vehicle speed sensor 28, compares the calculated value with its ideal value, determines the output current flowing to the reaction force compensation valves 23, 24, and simultaneously , the reaction force compensation valve 2 according to the signal from the steering amount sensor 29.
3 and 24, selectively sends the output current to the solenoid coils 90 and 91, selectively opens and closes the reaction force compensation valves 23 and 24, and controls the pressure oil of the accumulator 19.・
The steering force is selectively supplied to the reaction force chambers 46 and 47 of the valve 13, and the steering force can be increased or decreased according to changes in the sliding friction coefficient μ of the road surface, thereby making it possible to improve the operational feel and steering stability. There is.

Similarly, this controller 27 also determines, in relation to the truck, the ideal value of the reaction pressure corresponding to the loaded weight associated with the steering load (steering resistance) determined by the product of the road surface sliding friction coefficient μ and the load. is input in advance, and is calculated based on the signals from the pressure sensors 25, 26 and the vehicle speed sensor 28,
The calculated value and the ideal value are compared to determine the output current flowing through the reaction force adjustment valve 17, and the output current is passed through the electric actuator 71, so that the reaction pressure in the reaction chambers 46 and 47 is adjusted in advance. The opening degree of the reaction force adjustment valve 17 is adjusted so as to match the input ideal value, so that a steering force suitable for the loaded weight can be obtained.

Furthermore, this controller 27 is inputted with a predetermined steering pattern regarding the relationship between the steering wheel angle and the generated oil pressure, and the steering wheel rotation angle until the oil pressure is generated, and the pressure sensors 25, 26 , calculates based on the signals from the vehicle speed sensor 28 and the steering amount sensor 29, and compares the calculated value with the previously input steering pattern,
The output current for the reaction force compensation valves 23, 24 is determined, and the determined output current is applied to the solenoid coils 90, 91 of the reaction force compensation valves 23, 24, and the sensors 25, 26, 28, 29
For example, if there is play in the steering wheel, the play is the rotation angle of the steering wheel until oil pressure is generated, and the pressure sensor 25, 26 and the steering amount Since it is calculated based on the electric signal given from the sensor 29, the play is memorized, the play is taken into consideration, the next steering operation is predicted, and the solenoid coils 90 of the reaction force compensation valves 23, 24 are activated.
An output current is applied to the rotor 91 to reduce the play and prevent delay in operation, thereby making it possible to correct the cutting delay due to the play.

In this way, the controller 27 allows the power steering 10 to obtain a steering force adapted to the road friction value without being affected by changes in the load weight during braking, and that during normal driving, the controller 27 The sliding friction coefficient of the road surface μ,
A steering force adapted to the lateral acceleration, vehicle speed, and steering amount is obtained in the power steering 10, and further, in the power steering 10,
Control is performed so that the cutting delay is corrected.

The vehicle speed sensor 28 detects the traveling speed of the truck and is disposed on the output shaft of a transmission (not shown) mounted on the truck.

The steering amount sensor 29 is connected to the steering amount sensor 29.
A rotation sensor that detects the rotation speed, rotation direction, and rotation angle of the shaft, and is arranged around the steering shaft at a predetermined position on the steering shaft.

The pressure sensors 25, 26, vehicle speed sensor 28, and steering amount sensor 29 described above are of course electrically connected to the input circuit of the controller 27, and the output circuit of the controller 27 is connected to the reaction force adjustment. Electric actuator 7 of valve 17
1, and the solenoid of the reaction force compensation valves 23 and 24.
It is electrically connected to coils 90 and 91.

Therefore, the reaction force adjustment valve 17 and the reaction force compensation valves 23 and 24 are controlled by the controller 27 to disconnect the passage in response to signals from the pressure sensors 25 and 26, the vehicle speed sensor 28, and the steering amount sensor 29. Its area can be changed and it can be selectively opened and closed.

Next, the operation of the power steering 10 described above will be described in relation to the running state of the truck.Since the internal combustion engine is being operated, the oil pump 12 is driven, and the oil pump 12 is The flow rate of the discharged pressure oil is adjusted by the flow control valve 14, and a predetermined flow rate of the pressure oil flows into the supply side hydraulic piping 62, and the flow rate is adjusted by the flow control valve 14.
sent to.

If the spool 40 is placed in the neutral position as shown in the figure, the pressure oil sent to the pump port 41 passes through the return side hydraulic piping 63 and from the tank port 42. It is returned to its oil reservoir 15.

When pressure oil is thus discharged from the oil pump 12, the compensating pressure control valve 20 causes the pressure oil to be delivered to the accumulator 1 at a set pressure.
It is stored in 9.

At the same time, the controller 27 receives signals from the pressure sensors 25, 26, vehicle speed sensor 28, and steering amount sensor 29, and also receives rotation difference information and tire slip rate information from the anti-skid brake computer 30. is input, the output current flowing through the electric actuator 71 of the reaction force adjustment valve 17 and the solenoid coils 90, 92 of the reaction force compensation valves 23, 24 is controlled, and the reaction force chamber 4 of the control valve 13 is controlled.
Adjust the oil pressure in 6 and 47, and adjust the steering
It is prepared to obtain hydraulic reaction force suitable for wheel operation, that is, road surface friction value, braking related to the road surface friction value, lateral acceleration, vehicle speed, steering amount, and loaded weight, and also makes it possible to correct turning delay. I'm ready.

Now, if the truck is fully loaded with cargo and traveling at low speed on a straight paved road, the controller 27 inputs signals from the pressure sensors 25, 26, the vehicle speed sensor 28, and the steering amount sensor 29. It is calculated according to the input signal and compared with the optimal value of the power cylinder pressure and the ideal value of the reaction force pressure inputted in advance, and output signals for the reaction force adjustment valve 17 and the reaction force compensation valves 23 and 24, i.e. , determine the output current.

Since the road is paved and straight, the steering load (steering resistance), which is determined by the product of the road surface's sliding friction coefficient μ and the load, corresponds to the vehicle speed, the amount of steering, and the sliding friction coefficient μ of the road surface. An output current corresponding to the associated load weight flows from the controller 27 to the electric actuator 71 of the reaction force regulating valve 17, and the electric actuator 71 is driven. , the spool is slid into the spool chamber, and the cross-sectional area of the passage within the spool chamber is widened in accordance with the vehicle speed, steering amount and payload.

Therefore, if the truck is driven from a straight point to a curved point on the road, the steering wheel is turned either left or right depending on the curved point, and the control valve 13 is controlled. - If the valve spool 40 is slid in either direction by its steering, the pressure oil will flow into either the cylinder chamber 34 or 35 of the power cylinder 11 depending on the sliding direction of the spool 40. and one of the reaction force chambers 46 and 47 of the control valve 13.

For example, if the spool 40 is slid to the right in the figure, the pump port 41
is connected to the cylinder port 44 through the spool groove 55 of the spool 40, and then to the tank port 44.
The port 42 is connected to the spool groove 56 of the spool 40.
The pressure oil discharged from the oil pump 12 is sent to the cylinder chamber 35 of the power cylinder 11 through the communication passage 66, and the piston 32 is connected to the cylinder port 45 in the figure. , the pressure oil in the cylinder chamber 34 of the power cylinder 11 is slid to the right.
The oil is returned to the oil reservoir 15 via communication passages 64, 65 and return hydraulic piping 63.

As such, when pressure oil is supplied, a portion of the pressure oil is directed to the reaction chamber 46 via the reaction communication port 52 and the bore 50.

The reaction force during such steering is caused by the reaction force chamber 46.
During this low-speed running, the reaction force adjusting valve 17 is applied according to the loaded weight.
Since the passage cross-sectional area of the reaction force chamber 46 is widened, the pressure oil in the reaction force chamber 46 passes through the reaction force port 48 and is not excessively throttled by the reaction force adjustment valve 17, but instead flows into the other reaction force. It flows into the force chamber 47.

Furthermore, when the spool 40 is slid in the above-mentioned direction, the tank port 42 is connected to the spool groove 56, and the pressure oil in the reaction chamber 47 is
The oil is returned to the oil reservoir 15 via the return hydraulic line 63.

Therefore, the pressure drop caused by the reaction force adjustment valve 17 becomes smaller, the pressure difference between the left and right reaction force chambers 46 and 47 becomes smaller, and the pressure oil in the reaction force chamber 46 is reduced due to the sliding of the spool 40. In other words, when driving at low speeds with a full load, steering is performed with a small amount of operating force.

Also, if the steering wheel is turned in accordance with a curve in the road and the spool 40 in the control valve 13 is slid to the left in the figure, the pump port 41 will be inserted into the spool groove 54. In that tank
The ports 42 are respectively connected to the spool grooves 55, and the pressure oil discharged from the oil pump 12 is sent to the cylinder chamber 34 of the power cylinder 11 through the communication passage 64, and the piston 32 is shown in the figure. , the pressure oil in the cylinder chamber 35 of the power cylinder 11 is slid to the left.
The oil is returned to the oil reservoir 15 via the communication passage 66 and the return hydraulic piping 63.

Contrary to the case described above, the pressure oil in the reaction force chamber 47 passes through the reaction force port 49 and is not extremely throttled by the reaction force adjustment valve 17.
The pressure oil in the reaction chamber 46 is sent to the bore 5.
0, is returned to its oil reservoir 15 via the reaction force communication port 52, spool groove 55, tank port 42, and return side hydraulic piping 63.

Therefore, as in the case described above, the pressure drop caused by the reaction force adjustment valve 17 becomes smaller, the pressure difference between the left and right reaction force chambers 46 and 47 becomes smaller, and the pressure oil in the reaction force chamber 47 becomes smaller. , there is no large resistance to the sliding of the spool 40, and steering is performed with a small operating force.

Even during this low-speed driving that was explained as such,
The pressure sensors 25 and 26 are the control
The hydraulic pressure in the reaction chambers 46 and 47 of the valve 13 is sensed, converted into an electric signal, and given to its controller 27, which also receives input from its vehicle speed sensor 28 and steering amount sensor 29. The electrical signals from the pressure sensors 25 and 26 are calculated in relation to the electrical signals, and the output current is determined by comparing it with the optimal value of the power cylinder pressure and the ideal value of the reaction force pressure input in advance. controls the reaction force adjustment valve 17, and controls the reaction force chambers 46, 4.
Since the hydraulic pressure at 7 is controlled in a feedback manner, this power cylinder 10 can obtain a steering force suitable for the weight of the cargo loaded on the truck, and the operational feel and steering stability can be maintained constant.

Furthermore, during this low-speed driving, if the truck enters a curved area on the road where the road surface is frozen, the pressure sensors 25 and 26 correspond to the sliding friction coefficient μ of the road surface, and The oil pressure changed in the reaction force chambers 46 and 47, which corresponds to changes in the steering load (steering resistance) and lateral acceleration determined by the product of the friction coefficient μ and the load, is sensed, converted into an electric signal, and then controller 2
7, the controller 27 calculates according to the input electric signal, compares the calculated value with the optimal value of the power cylinder pressure input in advance, and adjusts the reaction force compensation valves 23 and 24. Determine the output signal, i.e., the output current, for

An output current corresponding to the steering load (steering resistance) and lateral acceleration determined by the product of the sliding friction coefficient μ of the road surface and the load is transmitted from the controller 27 to the solenoid coils 9 of the reaction force compensation valves 23 and 24.
0,91.

Therefore, one of the reaction force compensation valves 23 and 24 is opened, and the pressure oil stored in the accumulator 19 flows through one of the reaction force compensation pipes 21 and 22.
Reaction chambers 46, 4 of the control valve 13
directly and rapidly supplied to one side of 7,
The steering wheel is instantly weighted to prevent the steering wheel from turning too far, thereby preventing the truck from spinning or overturning.

Further, if the anti-skid brake is operated immediately after the truck enters a curve on the road where the road surface is frozen, the controller 27 receives the rotation difference from the anti-skid brake computer 100. information and tire slip rate information are input, a road surface friction value is calculated based on the information, the calculated value is compared with a braking pattern input in advance, and the output current for the reaction force compensation valves 23 and 24 is calculated. At the same time, the opening and closing of the reaction force compensation valves 23 and 24 are selected according to the signal from the steering amount sensor 29, and the output current is applied to the solenoid coil 9.
0,91, and the reaction force compensation valve 23,
24 is selectively opened and closed.

In this way, the reaction force compensation valves 23 and 24 are selectively opened and closed, in other words, one of the reaction force compensation valves 23 and 24 corresponding to the steering direction is opened, so that the accumulator 19 The stored pressure oil flows into one of the reaction force compensating pipes 21 and 22, and is directly and rapidly supplied to one of the reaction force chambers 46 and 47 of the control valve 13, and is then supplied to the steering wheel. Its steering is instantly weighted more precisely.
Overturning of the wheel is prevented more quickly, and the truck is accordingly placed in a position to reliably avoid spins and rollovers at an earlier stage.

Furthermore, if the truck enters a straight section of the road where the road surface is frozen, rather than a curved section where the road surface is frozen, the pressure sensors 25 and 26 will detect the sliding friction coefficient μ of the road surface. Detects the changed oil pressure in the reaction force chambers 46 and 47 corresponding to the change in the steering load (steering resistance) determined by the product of the changed road surface sliding friction coefficient μ and the load. The controller 27 calculates the calculated value according to the input electric signal and compares the calculated value with the optimal value of the power cylinder pressure input in advance. The output signal for the reaction force regulating valve 17, that is,
Determine the output current.

An output current corresponding to the changed steering load (steering resistance), that is, the changed road surface sliding friction coefficient μ, flows from the controller 27 to the electric actuator 71 of the reaction force regulating valve 17.

Therefore, the electric actuator 71 is driven with the output current, and in the reaction force regulating valve 17 the spool is slid into the spool chamber, the passage cross section in the spool chamber is narrowed, and the As a result, the steering wheel is instantly weighted, preventing the steering wheel from turning too far, thereby preventing the truck from spinning or overturning.

Also, if the anti-skid brakes are activated immediately after the truck enters a straight section of the road with such ice,
The controller 27 controls the anti-skid
Rotation difference information and tire slip rate information are input from the brake computer 100, a road surface friction value is calculated based on the information, the calculated value is compared with a braking pattern input in advance, and the reaction force compensation valve 23 . I'm in a position to get it.

Therefore, if the steering wheel is turned, its output current flows to one of its solenoid coils 90, 91 corresponding to the steering direction;
Then, since one of the reaction force compensation valves 23 and 24 is opened, the pressure oil stored in the accumulator 19 flows into one of the reaction force compensation pipes 21 and 22, and the reaction force of the control valve 13 is reduced. room 4
6, 47 directly and rapidly, the steering wheel instantly
Being weighted more precisely, overturning of the steering wheel is prevented more quickly and the truck is accordingly placed in a position to ensure avoidance of a spin or rollover sooner.

Further, a case similar to such low-speed traveling is when the truck is abandoned. Since the running speed is zero during this stationary station, the passage cross-sectional area of the reaction force adjustment valve 17 is expanded to the maximum by the output current from the controller 27, and the mutual interaction between the reaction force chambers 46 and 47 is The pressure difference becomes very small, so that the stationary operation takes place with very little operating force.

Next, if the truck travels at high speed on a straight section of a paved road, the controller 27 inputs signals from the pressure sensors 25, 26, the vehicle speed sensor 28, and the steering amount sensor 29, Calculations are made based on these input signals, and the output current for the reaction force adjustment valve 17 and reaction force compensation valves 23 and 24 is compared with the optimal value of the power cylinder pressure and the ideal value of the reaction force pressure input in advance. Determine.

Now, since the truck is traveling at high speed on a straight section of a paved road, the output current corresponding to the vehicle speed, amount of steering, and loaded weight is transmitted from the controller 27 to the reaction force regulating valve 17. The electric actuator 71 is driven, and accordingly, in the reaction force regulating valve 17, the spool is slid into the spool chamber, and the passage cross-sectional area in the spool chamber is The vehicle speed and steering amount,
The width is further narrowed in accordance with the sliding friction coefficient μ of the road surface, and is adapted to the loaded weight related to the steering load (steering resistance) determined by the product of the sliding friction coefficient μ of the road surface and the load.

Next, if the road changes from a straight section to a curved section, and the truck attempts to travel on the curved section of the road, the control valve 13 of the control valve 13 When the spool 40 is slid in either direction by the steering operation, the pressure oil is transferred to the cylinder chamber 34 of the power cylinder 11, depending on the sliding direction of the spool 40.
A part of the pressure oil is sent to either one of the reaction chambers 46, 47 of the control valve 13, and the piston 32 slides. In the force adjustment valve 17, since the cross-sectional area of the passage inside the spool chamber is narrowed by the spool, the pressure drop due to the reaction force adjustment valve 17 increases, and accordingly, the left and right reaction force chambers 46, The pressure difference within 47 increases. As a result, the pressure oil in one of the reaction force chambers 46 and 47 becomes a large resistance to the sliding movement of the spool 40.

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

Even during this high-speed running, the pressure sensor 25,
26 is the reaction force chamber 4 of the control valve 13
6, 47, converts it into an electrical signal, and sends it to its controller 27, which in turn converts the pressure sensor 25 into an electrical signal input from the vehicle speed sensor 28 and steering amount sensor 29. . This power steering 1
At 0, a steering force suitable for the weight of the cargo loaded on the truck is obtained, and the operational feel and steering stability are constant.

Also, if the truck is driven into a straight or curved section of the road when the road surface is frozen during high-speed driving, the power steering 1
0 is operated, but in this case, in the reaction force regulating valve 17, the passage cross-sectional area in the spool chamber is narrowed by the spool. Therefore, if the truck is on the road,
When the truck enters a straight or curved section of icy road, the steering wheel is instantly made heavier, preventing the steering wheel from turning too far and preventing the truck from spinning out or overturning. .

In particular, even if the anti-skid brake is activated immediately after the truck enters a straight or curved area on an icy road, the controller 27 receives rotation difference information from the anti-skid brake computer 100. and tire slip rate information, calculate the road friction value based on this information, compare the calculated value with the braking pattern input in advance, and calculate the output current for the reaction force compensation valves 23 and 24. In response to the signal from the steering amount sensor 29,
At any time, the output current is transferred to the reaction force compensation valve 23,
24 solenoid coils 90, 91, and when the steering wheel is steered, the steering wheel is instantly weighted more accurately and the steering wheel is not turned too far. be stopped more quickly,
Correspondingly, the truck is placed in a state where it can reliably avoid a spin or capsize at an earlier stage.

Next, to explain the steering delay correction operation of the power steering 10, if there is any play in the link mechanism of the power steering 10, the controller 27 will adjust the input signal from the vehicle speed sensor 28. Relatedly, the reaction force compensation valve 2 is calculated based on the input signals from the pressure sensors 25 and 26 and the steering amount sensor 29, and the calculated value is compared with a steering pattern input in advance.
3 and 24, and selectively send the output current to the solenoid coils 90 and 91 of the reaction force compensation valves 23 and 24 to selectively open and close the reaction force compensation valves 23 and 24. do.

When one of the reaction force compensation valves 23, 24 is opened, the pressure oil stored in the accumulator 19 flows into one of the reaction force compensation pipes 21, 22, and the reaction force chambers 46, 47 of the control valve 13 are opened. , the control valve spool 40 is rapidly slid, the oil is discharged from the oil pump 12, the flow is controlled by the flow control valve 14, and the compensating pressure control valve 20 is discharged. The pressure oil that has passed through this process controls the
The direction is controlled by a valve 13, and the power is supplied to one of the cylinder chambers 34, 35 of the power cylinder 11.

Since the power cylinder 11 is driven in this manner, play, or in other words, a delay in turning, occurring in the link mechanism of the power cylinder 10 is quickly avoided.

More specifically, in the power steering 10, an operating force transmission mechanism connecting the steering wheel and the control valve spool 40 of the control valve 13, such as a spline connection of the steering shaft, is used. If the steering wheel has a large play due to rattling, the control valve spool 40 of the control valve 13 will not move within the range of the play even if the steering wheel is rotated. Not sliding, its power cylinder 11
The pressures in the cylinder chambers 34 and 35 are kept substantially equal.

When the steering wheel is rotated in such a state, the controller 27 receives signals from the pressure sensors 25 and 26, the vehicle speed sensor 28, and the steering amount sensor 29, so The calculated value is compared with a steering pattern input in advance, and the solenoid coil 9 of the reaction force compensation valve 23, 24 is
Determine the output current flowing to one of 0 and 91.

The output current is the solenoid coil 90,
91, the reaction force compensating valve 23,
24 is opened, the pressure oil in the accumulator 19 flows into one of the reaction force compensation pipes 21 and 22, and the reaction force chamber 4 of the control valve 13 is opened.
6, 47, and at its control valve 13, its control valve 13
Valve spool 40 is quickly slid. With the rapid sliding of the control valve spool 40, oil is discharged from the oil pump 12 into one of the cylinder chambers 34, 35 of the power cylinder 11, and the flow control valve 14 controls the flow rate. Pressure oil is immediately supplied through the compensated pressure control valve 20 so that the power piston 32 is injected into the cylinder chambers 34, 35.
quickly moved to the other side. Of course, the selection of one of the cylinder chambers 34, 35 and the amount of pressure oil supplied correspond to the selection of one of the reaction chambers 46, 47 in the control valve 13 and the amount of pressure oil supplied. It is determined by the controller 27 according to the signal from the steering amount sensor 29, that is, the rotation speed, rotation direction, and rotation angle of the steering shaft.

For example, if the steering wheel is rotated clockwise and there is play in the spline joint of the steering shaft, the controller 27 calculates based on the input signal from the steering amount sensor 29 and The input steering pattern and its calculated value are compared to determine the output current, and the output current is applied to the solenoid coil 9.
0, and the reaction force compensation valve 23 is opened.

In this way, when the reaction force compensation valve 23 is opened, the high pressure oil stored in the accumulator 19 flows into the reaction force compensation pipe 21 and is supplied to the reaction force chamber 46 of the control valve 13. be done.

Since high pressure oil is supplied to the reaction force chamber 46, the control valve spool 40
is slid to the left in the figure, and the pump port 41 is the power cylinder. The port 43 is communicated via a ring groove 54, and the tank port 42 is communicated with the power cylinder port 44 via a ring groove 55.

As such, when the pump port 41 is connected to the power cylinder port 43 and the tank port 42 is connected to the power cylinder port 44, the oil pump 12
On the way, the pressure oil supplied from the flow control valve 14 and the compensation pressure control valve 20
The power flows through the supply side hydraulic piping 62, further flows into the communication passage 64, and flows into the cylinder chamber 34 of the power cylinder 11.
As the piston 32 is slid to the left in the figure, the pressure oil in the cylinder chamber 35 of the power cylinder 11 flows into the communication passage 66 and the return hydraulic piping 63 and returns to the oil reservoir 15. and in that way the power cylinder 11 is operated in the retracting direction.

Therefore, in the power steering 10, rattling occurs in the spline connection portion of the steering shaft in the operating force transmission mechanism that connects the steering wheel and the control valve spool of the control valve 13. Even if the so-called steering wheel has a large play, the steering wheel
If the wheel is rotated, even within its play, the power cylinder 11 operates properly and the power steering 10 steers the front wheel. Of course, in order to enable such operation, the controller 27 inputs signals from its pressure sensors 25, 26 and steering amount sensor 29, and controls its reaction force compensation valves 23,
The controller 27 determines the output current flowing through the solenoid coils 90 and 91 of 24.
determines the output current flowing through the solenoid coils 90, 91 of the reaction force compensation valves 23, 24 such that the relationship between the respective signals from the sensors 25, 26, 29 remains substantially constant. . As a result, by selectively opening and closing the reaction force compensation valves 23 and 24 under the control of the controller 27, the relationship between the amount of operation of the steering wheel and the pressure inside the power cylinder 11 is adjusted to a predetermined value. It is kept in the relationship and its increased play is avoided.

Furthermore, once the play is memorized, the controller 27 takes that play into account and predicts the next steering play, and the reaction force compensation valve 23,
By changing the output current flowing through 24 and repeating such an operation, it operates to prevent the increase in play in advance.

Also, if the steering wheel is rotated in the opposite direction as described above, the power steering 10 is operated substantially in the opposite direction as described above. That is, by the controller 27,
Since the output current flows through the solenoid coil 91 of the reaction force compensation valve 24, the reaction force compensation valve 24 is opened, and the high pressure oil stored in the accumulator 19 flows into the reaction force compensation piping 22. The reaction force chamber 47 of the control valve 13 is supplied with the control valve spool 40.
is slid to the right in the figure, the pump port 41 communicates with the power cylinder port 44 via a ring groove 55, and the tank port 42 communicates with the power cylinder port 45 via a ring groove 56. be contacted via.

As such, when the pump port 41 is connected to the power cylinder port 44 and the tank port 42 is connected to the power cylinder port 45, the oil pump 12
On the way, the pressure oil supplied from the flow control valve 14 and the compensation pressure control valve 20
The power is then passed through the supply side hydraulic piping 62, and further into the communication passage 66.
flows into the cylinder chamber 35 of the cylinder 11, causing its power piston 32 to slide to the right in the figure;
Accordingly, the pressure oil in the cylinder chamber 34 of the power cylinder 11 flows into the communication passages 64, 65 and the return side hydraulic piping 63 and is returned to the oil reservoir 15, and in this way, the power
The cylinder 11 is operated in the extension direction.

This power steering 10 therefore steers its front wheels in the opposite direction to that described above.

Next, if there is a delay in turning the front wheels when the steering wheel is operated,
The controller 27 includes the steering amount sensor 29
The operating speed of the steering wheel sensed by the steering wheel is inputted and compared with the stored steering pattern to determine the output current, and the output current is applied to the solenoid coils 90,
Selectively stream to 91.

That is, as in the case of play described above, the controller 27 selectively operates the reaction force compensating valves 23 and 24 to transfer the high pressure oil stored in the accumulator 19 to the control valve 13.
selectively feeding the reaction chambers 46, 47 of the control valve spool 40 to quickly slide the control valve 13, thereby causing the control valve 13 to perform a rapid valve switching operation to control the power cylinder. 11 is quickly driven.

At that time, the controller 27 memorizes the degree of steering delay, takes this steering delay into account, predicts the steering delay of the next steering, and controls the steering amount sensor 27 so that the steering delay is reduced. An output current that has been compared and calculated based on the signals sensed by the solenoid coils 90 and 91 is selectively applied to the solenoid coils 90 and 91, and the reaction force compensation valves 23 and 24 are selectively opened.

As a result, a delay in turning the front wheels relative to the operation of the steering wheel is prevented, and a change in the feeling of operating the steering wheel due to the delay in turning is prevented.

The power steering 10 described above is
Although it was described as steering the front wheels of a truck with anti-skid brakes, if the rear axle of a vehicle with anti-skid brakes is configured to steer, the power
The steering 10 is then pivotally connected to both ends of the axle and is also applicable to rotatably directed rear wheel steering.

As is clear from the specific embodiments of the invention described above with reference to the drawings,
For those with ordinary knowledge in the technical field to which this invention pertains, the content of this invention can be objectively understood to derive from and incorporate the nature and substance of the invention. Other aspects may be readily embodied.
Of course, the content of this invention is essential for the realization of the invention, depending on the problem of the invention.

Advantages and Benefits of the Invention As 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, and a control cylinder having a pair of reaction force chambers.
The valve is configured in a hydraulic circuit to steer a pair of front wheel axles swingably connected to both ends of the front axle of a vehicle equipped with an anti-skid brake, and the compensation hydraulic piping is configured on the upstream side of the control valve. , the hydraulic circuit is branched from the supply side hydraulic piping, the accumulator is connected to the compensation hydraulic piping, and the compensation pressure control valve is arranged in the valve body and the spool bore of the valve body so as to be able to reciprocate and slide. a back pressure chamber assembled with a spool and a pressure setting spring acting on the spool and causing pressure oil directed from the accumulator to act on the spool against the pressure setting spring; A portion of the pressure oil flowing to the control valve is supplied to and stored in the accumulator, and the pressure in the accumulator is maintained at the set value downstream of the branch point of the compensating hydraulic line and upstream of the accumulator. located across its supply side hydraulic piping and compensation hydraulic piping,
A pair of reaction force compensation piping is connected between the reaction force chamber of the control valve and the accumulator, the pair of reaction force compensation valves are disposed in the reaction force compensation piping, and the controller is connected between the reaction force chamber of the control valve and the accumulator. Information on the rotation difference between the driving wheel and the driven wheel and tire slip rate information during braking are input from the anti-skid brake computer,
In addition, signals are input from a pair of pressure sensors connected corresponding to the reaction force chamber of the control valve, and based on that information and input signals, a road surface friction value is calculated, and the calculated value and the steering amount sensor The power steering system used in the vehicle of the present invention avoids complicating the structure of the control valve. Pressurized oil maintained at a set pressure value is available for reaction force compensation, and even if the anti-skid brake is activated immediately after entering a frozen or slippery surface. , the controller calculates a road surface friction value based on the rotation difference information and tire slip rate information given from the anti-skid brake computer, and uses the calculated value and the steering amount sensor as a signal or a signal from the pressure sensor. Accordingly, the reaction force compensation valve is selectively opened and closed, and the accumulator's pressure oil is selectively supplied to the pair of reaction chambers of the control valve, so that the steering wheel is instantly and highly accurately controlled. This ensures that the steering wheel is not overturned very quickly, ensuring that the vehicle spins out or rolls over at a very early stage, improving driving stability and adapting the road friction values. In this way, road friction sensitivity characteristics and load sensitivity characteristics can be obtained, and even when driving normally,
The coefficient of sliding friction μ of the road surface, that is, the steering load (steering resistance) determined by the product of the sliding friction coefficient μ of the road surface and the load, the loaded weight, lateral acceleration, vehicle speed, and steering related to the steering load (steering resistance). A steering force is obtained which is adapted to the quantity, in particular to the sliding friction coefficient μ of the road surface, in other words:
Depending on the steering load (steering resistance), the steering wheel is made heavier or lighter, preventing the steering wheel from turning too much, and preventing the vehicle from spinning due to turning the steering wheel too much. Overturning is prevented, and in this way, excellent road friction sensitivity characteristics,
Load-sensitive characteristics, lateral acceleration-sensitive characteristics, and speed-sensitive characteristics can be obtained, and in addition, it is possible to appropriately compensate for switching delay, and the operating feel and steering stability can be maintained constant regardless of whether the vehicle is empty or loaded. This relieves the driver from the physical and mental fatigue caused by steering, and is very useful for vehicles equipped with anti-skid brakes.

[Brief explanation of the drawing]

The figure is a schematic diagram showing a specific example of the power steering used in the vehicle of the present invention applied to a truck equipped with anti-skid brakes. 11...Power cylinder, 12...Oil.
Pump, 13... Control valve, 14...
...Flow control valve, 15...Oil reservoir, 16...Reaction force adjustment passage, 17...
Reaction force adjustment valve, 18...compensation hydraulic piping, 19...accumulator, 20...compensation pressure control valve, 21,
22...Pair of reaction force compensation piping, 23, 24...Pair of reaction force compensation valves, 25, 26...Pressure sensor, 2
7... Controller, 28... Vehicle speed sensor, 29
...Steering amount sensor, 62 ... Supply side hydraulic piping, 6
3...Return side hydraulic piping, 64, 65, 66...Communication path, 100...Anti-skid brake computer.

Claims (1)

[Claims] 1. A power cylinder having a pair of cylinder chambers, an oil pump, and a control valve having a pair of reaction force chambers are configured in a hydraulic circuit, and both ends of a front axle of a vehicle equipped with an anti-skid brake are provided. In a device that steers a pair of front wheel axles that are swingably connected to the control valve, the compensation hydraulic piping is branched from the supply side hydraulic piping of the hydraulic circuit upstream of the control valve, and the accumulator is connected to the compensation hydraulic piping. a compensating pressure control valve connected to and assembled with a valve body, a spool reciprocally slidably disposed in a spool bore of the valve body, and a pressure setting spring acting on the spool and directed from the accumulator. a back pressure chamber for applying pressure oil to the spool against the pressure setting spring; and supplying and storing a portion of the pressure oil flowing from the oil pump to the control valve to the accumulator; , located downstream of the branch point of the compensating hydraulic piping and upstream of the accumulator astride the supply hydraulic piping and the compensating hydraulic piping, so as to maintain the pressure of the accumulator at the set value. A force compensation pipe is connected between the reaction force chamber of the control valve and the accumulator, a pair of reaction force compensation valves are disposed in the reaction force compensation pipe, and the controller is connected to the drive wheel during normal running. The information on the rotation difference between the driven wheels and the tire slip rate during braking is input from the computer of the anti-skid brake, and based on that information, the road surface friction value is calculated, and then the calculated value and the steering amount sensor are input. or, depending on the signal of
A power source used in a vehicle that is characterized by selectively opening and closing the reaction force compensation valve in response to the signals of a pair of pressure sensors connected to the reaction chambers of the control valve and their calculated values.・Steering.