JPS63134375A - Power steering used for vehicle - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a delay in turning of a steering wheel and a delay in a steering motion, by a method wherein, according to signals from a car speed sensor, a steering sensor, and a load sensor, a current to an electric drive type control valve is controlled. CONSTITUTION:An electric drive type control valve 15 is a spool type 4-way solenoid containing a valve body 46, spool, and an electronic actuator, and in the hydraulic circuit of a power steering, it is situated in auxiliary hydraulic pipings 22 and 23. The valve 15 is electrically connected to a controller 16, and an acutuator is driven by means of 8 current controlled by the controller 16. The inlet side of the controller 16 is electrically connected to a car speed sensor 24, a steering sensor 25, and a load sensor 26, its outlet side is connected to an electromagnetic actuator, and according to a signal from each sensor, a current to an electromagnetic actuator is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to power steering used in vehicles which is speed and load sensitive and is of the steering lag corrected type.

Background Art In general, speed-sensitive power steering has become popular in automobiles, but in this type of power steering, the operating force changes depending on the load, resulting in differences in operating feel and steering stability. Moreover, regarding cutting delay correction,
At present, no special consideration has been given to this issue.

In addition, in power steering, hydraulic pumps and power cylinders are usually designed to ensure the ability to hold the station when stopped and the steering force required when driving at very low speeds, so they require large amounts of pressure oil and power cylinders. Even when driving at high speeds, where large steering forces are not required, a large load is placed on the engine, which tends to reduce fuel consumption.

Purposes and Problems of the Invention The purpose and problem of this invention is to suppress the increase in the size of the hydraulic pump and the pressure receiving area of the piston in the power cylinder, to suppress wasteful consumption of engine generated power, and to improve the fuel consumption rate of the engine. When the vehicle is running, the steering force is changed appropriately according to the load, and when the vehicle is stationary, the steering force is reduced, preventing a delay in turning the steering wheel, that is, a delay in steering operation, and reducing fatigue caused by steering. The main purpose of the company is to provide power steering for use in vehicles.

Summary of the structural invention related to the object/problem: Contents of the claimed invention In relation to the above-mentioned object/problem, the power steering used in the vehicle of this invention is swingably connected to both ends of the front axle. a main booster that steers a pair of front wheel axles;
an auxiliary booster that supplements the steering force of the main booster, a hydraulic pump, and a manual control valve disposed in the main hydraulic piping that connects the main booster to the hydraulic pump;
an electrically actuated control valve located on an auxiliary hydraulic line connecting the auxiliary booster to the hydraulic pump;
The controller includes a controller that controls the current flowing to the electrically driven control valve according to signals from the vehicle speed sensor, steering sensor, and load sensor, and controls the vehicle by the vehicle speed sensor, steering sensor, and load sensor. The controller detects the driving condition, quickly judges steering wheel operation and load increase/decrease, and controls the vehicle.
The current flowing through the valve is controlled, pressure oil is promptly supplied to the auxiliary booster, the auxiliary booster is made to supplement the steering force of the main booster, and the auxiliary booster is controlled to compensate for the switching delay of the main booster, that is, to control the operation of the auxiliary booster. Correct the delay.

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

The figure shows specific example 10 of power steering used in a vehicle of the present invention applied to a cab-over type truck.
It shows.

The power steering 10 is connected to a front axle (not shown) located forward of the chassis frame (not shown) of the truck.
A double sector shaft 35 is connected to a pair of front wheel axles 60 and 61 which are swingably connected to both ends of the wheel (not shown) via a knuckle (not shown) and a king pin (not shown).
, a front wheel 62° 63 connected via a pitman arm 57, a drag link 58 and a knuckle arm 59, and rotatably supported on its front wheel axle 60.61.
The front wheel axle 60.6
1, an auxiliary booster 12 that supplements the steering force of the main booster 11, and a hydraulic pump 13.
A manual control located on the main hydraulic line 20.21 connecting the main booster 11 to the hydraulic pump 13.
Auxiliary hydraulic piping 22 connecting the auxiliary booster 12 to the valve 14 and the hydraulic pump 13. ．． Electrically driven control valve 15 located at 23 and vehicle speed sensor 2
4. A controller 16 that controls the current flowing through the electrically driven control valve 15 in response to signals from the steering sensor 25 and the load sensor 26, a flow control valve 17, and a control valve bypass 18; The oil reservoir 19 is configured to include an oil reservoir 19.

The main booster 11 includes a steering gear box (not shown) that incorporates a manual control valve 14 that is switched and operated by a steering wheel 55 via a steering shaft 56 to enable manual steering; In addition, it is configured as a dual cylinder type that is integrated with the auxiliary booster 12, incorporates the manual control valve 14, and furthermore, the sub-cylinder body 36 of the auxiliary booster 12 is integrated.
A main cylinder body 30 that is integrally manufactured,
Cylinder bore 3 of its main cylinder body 30
1 so that it can slide back and forth, and its cylinder
A piston 34 that forms a pair of cylinder chambers 32 and 33 within the bore 31 and is engaged with the piston 34,
A double sector shaft 35 transmits the force and movement of the piston 34 to the pitman arm 57.

The main booster 11 also communicates between an oil port (not shown) of one cylinder chamber 32 and a cylinder port (not shown) of the manual control valve 14 corresponding to the oil port. (not shown) and the oil port (not shown) of the other cylinder chamber 33.
(not shown) and a cylinder port (not shown) of the manual control valve 14 corresponding to the oil port, the manual control valve 14 Accordingly, the cylinder chambers 32, 33 are configured to be switchable and connectable to the main hydraulic pipes 20, 21, that is, the supply side and return side hydraulic pipes 20,21.

In the main booster 11 so configured, the force and movement of its piston 34 is transmitted to its double sector shaft 35, pitman arm 57, drag link 58.
and via the knuckle arm 59 to the front wheels 62, 63, so that the main booster 11 steers the front wheels 62, 63.

The auxiliary booster 12 includes a sub-cylinder body 36 that is integrally manufactured with the main cylinder body 30 of the main booster 11, and a sub-cylinder body 36 that is integrally manufactured with the main cylinder body 30 of the main booster 11.
A pair of cylinder chambers 3 are fitted in the cylinder bore 37 of the cylinder bore 37 in a reciprocating manner.
8.39 and its double sector shaft 35
The piston 40 is meshed with the piston 40.

In addition, this auxiliary booster 12 has its sub-cylinder
The body 36 is provided with an oil port 41.42 which is connected to the hydraulic pump 13 and the oil reservoir 19 by the auxiliary hydraulic line 22.23. Of course, □ the auxiliary hydraulic pipe 22.23 is the supply and return hydraulic pipe 22.23, which is connected to the main hydraulic pipe 20.21, i.e. the supply and return hydraulic pipe 20.21. .

The main booster 11 and the auxiliary booster 12 are each manufactured so as to provide half the output required for stationary parking or extremely low speed running.

The hydraulic pump 13 is driven by a diesel engine (not shown) mounted on the truck and controls the manual control valve 14 to supply pressure oil to the main booster 1 and the auxiliary booster 2. located in the supply hydraulic line 20 connecting the oil reservoir 19 to the pump port 44;
The oil in the diesel engine 9 is sucked up and pressurized so that the amount of pressurized oil discharged is approximately proportional to the number of revolutions of the diesel engine. Of course, this hydraulic pump 13 is manufactured to have a similar configuration to a hydraulic pump used in existing power steering systems, so a description thereof will be omitted.

The manual control valve 14 is configured as a hydraulic reaction type spool valve, and is installed in the main cylinder body 30 of the main booster 1 and connected to the input shaft ( A spool (not shown) is connected to a spool shaft (not shown) fixed to a spool shaft (not shown), and the valves are switched by the steering wheel 55 via the steering shaft 56, and the pump Connecting the supply side and return side hydraulic piping 20.21 to the port 44 and the tank port 45, and controlling the direction of the pressure oil discharged from the hydraulic pump 13 and whose flow rate is controlled by the flow control valve 17, It supplies the main booster 11 and also controls the direction of the pressure oil worked in the main booster 11, and controls the direction of the oil that is on the suction side of the hydraulic pump 13.
The pressure oil is returned to the reservoir 19.

This manual control valve 14 includes a valve body 43 having a valve bore (not shown), a valve body 43 that is arranged to be able to slide back and forth in the valve bore, and a pair of reaction valves at both ends of the valve bore. The valve body 43 has a pump port 44 and a tank port 45 opened to the valve bore at predetermined positions. , a plurality of cylinder ports (not shown) are formed.

In addition, the valve body 43 has a reaction
A pair of reaction ports (not shown) are formed in the valve body 43 of the chamber, and the reaction ports are connected to a reaction communication passage (not shown).
A throttle (not shown) is placed in the reaction communication path.

As the spool is slid back and forth into the valve bore, the spool switches and connects the pump port 44 to the plurality of cylinder ports and the plurality of cylinder ports to the tank port 45. enable.

As the spool is slid back and forth into the valve bore, it also connects a pair of communication boats (not shown) that switch and connect the pump port 44 and tank port 45 to the reaction chamber. We are prepared.

With this manual control valve 14 having such a structure, pressure oil discharged from the hydraulic pump 13 and whose flow rate is adjusted by the flow control valve 17 is delivered to the cylinder chambers 32 and 33 of the main booster 11. For supply, the pump port 44 is connected to the outlet 53 of the flow control valve 17 in the supply hydraulic line 20 and the tank port 45 is connected to the outlet 53 of the flow control valve 17 in the return hydraulic line 21.・Reservoir 19
are connected to each.

The electrically driven control valve 15 is a valve.
body 46 and its valve bore (
A spool-type four-way solenoid valve includes a spool (not shown) disposed so as to be reciprocally slidable in a spool (not shown), and an electronic actuator (not shown), which controls the hydraulic circuit of the power steering 10. In this case, the auxiliary hydraulic piping 2
2.23, and in the electric circuit of the power steering 10, the spool is driven by an electromagnetic actuator that is electrically connected to the controller 16 and through which a current controlled by the controller 16 flows. , the pump port 47, cylinder port 48, 49 and tank port 50 opened to the valve bore are switched and connected from the hydraulic pump 13 to the auxiliary booster 12, and from the auxiliary booster 12. directional control of the flow of pressure oil from and to its oil reservoir 19.

The controller 16 has an input side connected to the vehicle speed sensor 24.
, is electrically connected to the steering sensor 25 and the load sensor 26, and the output side is electrically connected to the electromagnetic actuator of the electrically driven control valve 15, and the vehicle speed sensor 24, the steering sensor 25 and the load sensor 26 are electrically connected to the electromagnetic actuator of the electrically driven control valve 15. The electrically driven control valve 15 controls the current flowing through the electromagnetic actuator in response to a signal from the
The power steering system 10 is operated by port switching connection to provide speed-sensitive characteristics, load-sensitive characteristics, and switching delay correction characteristics to the power steering 10. The power supply circuit is the same as that of the truck.
(not shown) is shared.

The controller 16 responds to signals from the vehicle speed sensor 24 and the load sensor 26 to provide the power steering 10 with speed-sensitive characteristics such that the main booster 11 is activated at low speeds up to a predetermined speed.
is driven at full power, and at the same time its auxiliary booster 12
is driven at a relatively high power state to lighten the steering of the steering wheel 55, and when traveling at a speed exceeding a predetermined speed, the main booster is driven at full power state, At the same time, the auxiliary booster 12 is driven at a gradually lower rate of output depending on the traveling speed to make the steering of the steering wheel 15 heavier.

The controller 16 also responds to signals from the vehicle speed sensor 24 and the load sensor 26 to provide the power steering 10 with the load sensitivity characteristics.
In the event of emplacement, its main and auxiliary boosters11.12
When driving, the main booster 11 is driven to lighten the steering of the steering wheel 55.
Only the steering wheel 55 is driven, and the steering of the steering wheel 55 is prevented from becoming too light.

Further, in order to provide the power steering 10 with the turning delay correction characteristic, the controller 16 controls the turning start and turning operation of the main booster 11 in response to signals from the vehicle speed sensor 24 and the steering sensor 25. First, the auxiliary booster 12 is driven instantaneously in accordance with the direction of the steering wheel operation, in other words, the direction of rotation of the steering wheel 55, ahead of the drive of the main booster 11, and the auxiliary booster 12 is constantly driven. The cutting delay caused by the main booster 11 being driven is suppressed.

The vehicle speed sensor 24 connected to the input side of the controller 16 detects the traveling speed of the truck, and is arranged on the output shaft of a transmission (not shown) mounted on the truck, and is also used for steering the truck. sensor 25
detects the rotational direction, rotational speed, and rotational angle of the steering wheel 55, that is, the steering shaft 56, and is arranged on the steering shaft 56 at a predetermined position. is a pressure sensor, which is disposed in the supply side hydraulic piping 20 connecting the main booster 11 to the hydraulic pump 13, and senses the pressure of the pressure oil discharged from the hydraulic pump 13 that corresponds to the load. do.

The flow control valve 17 is located in the hydraulic circuit in a supply hydraulic line 20 connecting the manual control valve 14 to the hydraulic pump 13 and oil reservoir 19, and also in a control valve bypass. At 18, it is connected to the return side hydraulic piping 21.

The flow control valve 17 has an inlet 52 connected to the discharge side of the hydraulic pump 13, an outlet 53 connected to the pump port 44 of the manual control valve 14, and a return side hydraulic line 21. The configuration includes a valve casing 51 with a return port 54 connected thereto, and an oil return control spool (not shown) disposed in the valve casing 51 so as to be able to reciprocate. The flow rate of the pressure oil sent to the control valve bypass 18 is adjusted to send a predetermined flow rate to the outlet 53 thereof, and the excess flow rate of the pressure oil is sent from the return port 54 to the oil reservoir 19 of the control valve bypass 18.
Return after .

Of course, the flow control valve 17 is manufactured to have a similar structure to a flow control valve used in existing power steering systems, and a detailed explanation of its structure will be omitted.

Next, the operation of the power steering 10 described above will be described in relation to the running state of the truck. Since the diesel engine is being operated, the hydraulic pump 13 is driven, and the hydraulic pump 13 discharges air. The flow rate of the supplied pressure oil is adjusted by the flow control valve 17, and a predetermined flow rate of the pressure oil is controlled by the supply side hydraulic piping 20.
．． 22 and its control valves 14, 15
pump port 44.47.

If the steering wheel 55 is in the neutral position, the pressure oil sent to the pump port 44.47 passes through the return hydraulic piping 21.23 to the tank port 45°. 50 and returned to its oil reservoir 19.

At the same time, the controller 16 receives signals from the vehicle speed sensor 24, steering sensor 25, and pressure sensor 26, and controls the electrically driven control valve 1.
The electric current flowing through the electromagnetic actuator 5 is controlled to cause the electrically driven control valve 15 to perform a valve switching connection operation.

Now, if the trunk is fully loaded and travels on the road at a low speed up to a predetermined speed, the controller 16 inputs signals from the vehicle speed sensor 24, steering sensor 25, and pressure sensor 26, and The calculation is performed in accordance with the input signal, the output current is determined, and the output current is passed through the electromagnetic actuator of the electrically driven control valve 15, so that the electromagnetic actuator is driven and the electrically driven control valve 15 is operated. The spool is slid into the valve bore of the valve body 46 in response to the steering of the steering wheel 55, ie, the direction of rotation, the speed of rotation, and the angle of rotation.

Therefore, the main booster 11 is discharged from the hydraulic pump 13 and the flow control valve 17
At the same time, the auxiliary booster 12 is discharged from the hydraulic pump 13 and driven by the directional control valve 14 of the hydraulic oil whose flow rate is regulated by the manual control valve 14. Pressure oil whose flow rate is regulated at 17 is directionally controlled and supplied by the electrically driven control valve 15, and the front wheels 62, 63 are driven by the double sector shaft 35,
It is steered by its main booster 11 and auxiliary booster 12 via a pitman arm 57, a drag link 58 and a knuckle arm 59.

In this way, the steering force of the main booster 11 is supplemented by the auxiliary booster 12, so that steering is performed with a small operating force. Of course, the controller 16 is
According to the signals from the vehicle speed sensor 24 and the steering sensor 25, an output current for correcting the turning delay is calculated, and the output current is caused to flow through the electromagnetic actuator of the electrically driven control valve 15. 15, and advance it further than the main booster 11 at the beginning of the cutting start and the start of the cutting delay operation of the main booster 11,
Since the auxiliary booster 12 is driven instantaneously, a delay in turning the steering wheel 55, that is, a delay in steering operation is suppressed.

Additionally, if the trunk is traveling at a high speed that exceeds a predetermined speed, the controller 16 controls the vehicle speed sensor 24, steering sensor 25,
The signals from the pressure sensor 26 and the pressure sensor 26 are input, calculations are made according to the input signals, and the output current is sent to the electromagnetic actuator of the electrically driven control valve 15, so that the electromagnetic actuator is driven and the electrically driven control valve 15 is driven. - In the valve 15, the spool is slid into the valve bore of the valve body 46, connecting the pump port 47 to the tank port 50 and at the same time connecting the cylinder ports 48, 49 to each other. Connecting.

Therefore, the auxiliary booster 12 is placed in an idle state, and the main booster 11 is discharged from the hydraulic pump 13 and the pressure oil whose flow rate is regulated by the flow control valve 17 is in the manual control valve. 14
directionally controlled, supplied and driven by its front wheels 62
．． 63 is steered by its main booster 11 via its double sector shaft 35, pitman arm 57, drag link 58 and knuckle arm 59.

In this way, since steering is performed only by the main booster 11, a relatively large operating force is required for steering during high-speed running, and running stability is improved.

Even in the case of high-speed running, the controller 16 calculates an output current for steering delay correction according to the signals from the vehicle speed sensor 24 and the steering sensor 25, and applies the output current to the control valve 15. to the electromagnetic actuator to drive its control valve 15, and at the beginning of the main booster's cut-off and cut-back operations,
The auxiliary booster 12 is instantaneously driven ahead of the main booster 11 to suppress a delay in turning the steering wheel 55, that is, a delay in steering operation.

Further, when the truck is parked, the output current is calculated according to the signals from the vehicle speed sensor 24 and the pressure sensor 26, and the output current is applied to the control system.
The signal is supplied to the electromagnetic actuator of the valve 15, and the control valve 15 is switched to operate, thereby driving the auxiliary booster 12.

Therefore, both its main and auxiliary booster 11.12 are driven, its front wheels 62.63 are steered by its main and auxiliary booster 11.12, and its stationary action takes place very lightly.

Conveniences and Benefits of the Invention From the above, it can be seen that the power steering system used in the vehicle of this invention is more advantageous than the speed-sensitive power steering systems used in vehicles that have already been proposed and used. , a main booster steers a pair of front wheel axles swingably connected to both ends of the front axle, an auxiliary booster supplements the steering power of the main booster, and a manual control valve steers the main booster with a hydraulic pump. an electrically actuated control valve is located in the auxiliary hydraulic line connecting the auxiliary booster to the hydraulic pump; Since the power steering system used in the vehicle of the present invention is equipped with a configuration that controls the current flowing through the electrically driven control valve in accordance with a signal, the vehicle speed sensor, steering sensor, and load sensor are used to control the current flowing through the electrically driven control valve. Detects the driving condition,
The controller quickly judges steering wheel operation and load increase/decrease, controls the current flowing to the control valve, and drives the auxiliary booster at a relatively large output state when driving at low speeds up to a predetermined speed. The steering force of the main booster driven at full power is supplemented by the steering force of the auxiliary booster, and at the same time, the auxiliary booster is made to compensate for the turning delay caused by the main booster, and the steering force of the main booster, which is driven at full power, is compensated for by the auxiliary booster. When the vehicle exceeds the maximum output speed, the auxiliary booster is driven at a gradually decreasing rate of output depending on the traveling speed, and the slight steering force of the auxiliary booster is supplemented with the steering force of the main booster, which is driven at full output. Especially,
At high speeds, only its main booster is driven, and at the same time,
The steering delay caused by the main booster is compensated for by the auxiliary booster, and in this way, when driving at low speeds, the steering
Delay in turning the wheels, so-called delay in steering operation, is avoided, and steering is performed with a small steering force.In addition, during medium and high speed driving, delay in steering operation is similarly avoided, and relatively little effort is required for steering. Large steering forces are required, driving stability is improved, and, moreover, in the case of stationary operation, both the main and auxiliary boosters are driven, and the steering is carried out very lightly; As the auxiliary pump is driven, it is possible to suppress the increase in the size of the hydraulic pump and the pressure-receiving area of the piston in the power cylinder, suppressing wasteful consumption of engine generated power, and reducing the engine's fuel consumption rate. The steering force has been improved, and even when driving, the steering force can be changed appropriately according to the load, and for the driver,
Fatigue due to steering is reduced, and applicability to large vehicles is particularly improved, and it becomes very useful for such large vehicles.

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

[Brief explanation of the drawing]

The figure is a schematic diagram showing a specific example of a power steering system used in a vehicle according to the present invention, which is applied to a trunk. 11... Main booster, 12... Auxiliary booster, 13
... Hydraulic pump, 14 ... Manual control valve, 15 ... Electrically driven control valve, 1
6... Controller.

Claims (1)

[Claims] A main booster for steering a pair of front wheel axles swingably connected to both ends of a front axle, an auxiliary booster for supplementing the steering force of the main booster, a hydraulic pump, and a hydraulic pump for the main booster. A manual control valve located on the main hydraulic piping that connects the main booster, an electrically driven control valve located on the auxiliary hydraulic piping that connects the auxiliary booster to the hydraulic pump, a vehicle speed sensor, and a steering sensor. , and a controller for controlling current flowing through the electrically driven control valve in response to a signal from a load sensor.