JPH0420828B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic sawing handling device for effectively preventing wheel skidding during steering of a vehicle.

In a typical four-wheeled vehicle, the rotation of the engine located at the front of the vehicle is transmitted to the rear wheels via a propeller shaft, and the rotation of the rear wheels enables the vehicle to move.
By decelerating the rotation of the propeller shaft and transmitting it to the rear wheels, the deceleration rate in the transmission is reduced. In addition, when the vehicle turns, the outer wheels travel a longer distance than the inner wheels, and in order to prevent the inner wheels from rotating while slipping and becoming unable to rotate smoothly, the left and right rear wheels (driving wheels) are made independent. These are connected by a differential gear so that the rotation of the propeller shaft is transmitted to the left and right rear wheels at different rates.

Although differential gears have the above-mentioned advantages, even if the wheel on the side with greater contact resistance with the road stops rotating, only the wheel on the side with lower contact resistance will rotate, or the brake may fail. When the vehicle is heaved to one side, it has the disadvantage that one wheel is rotated more than the other wheel, making it more likely to cause sideways skidding.

For this reason, conventionally, in order to minimize the side slip of the wheels when turning,
Some experienced drivers perform so-called sawing handling, in which the steering wheel is turned in small increments and then turned back and forth to restore the gripping force of the wheels to the road surface.

However, since the operation of sawing handling is technically advanced, it is extremely difficult for ordinary drivers to acquire this ability, and many of them turn the steering wheel at a predetermined steering angle all at once.
This resulted in wheel skidding, resulting in tire wear and tire squeaking. In addition, skidding caused vehicle collisions.

The present invention has been made in view of the above conventional problems, and calculates an appropriate sawing steering angle according to the running conditions and steering conditions of the vehicle, and adjusts the sawing handling during steering based on the calculation result of this sawing steering angle. It is an object of the present invention to provide an automatic sawing handling device that can perform sewing automatically.

In order to achieve this object, the present invention provides a pulsation generating valve in the power steering hydraulic circuit, which is driven by an oscillating pulse with a frequency corresponding to the vehicle speed, steering angle, and steering angular velocity. The structure is such that the displacement operation and the discontinuation of the operation are repeated.

An embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram of an automatic sawing handling device, in which 1 is an engine, 2 is a hydraulic pump for power steering driven by this engine, and 5 is a hydraulic pump connected to the hydraulic pump 2 via hydraulic circuits 3 and 4. A connected power steering actuator for steering assistance.

This power steering actuator 5 has a power steering control valve 6. This power steering control valve 6 directs oil supplied from the hydraulic pump 2 through the hydraulic circuit 3 to either one of the hydraulic chambers 9 and 10 separated from each other by a power piston 8 inside the power cylinder 7. Operates to supply selectively. Therefore, the power piston 8 moves in either direction in the axial direction within the power cylinder 7 to assist in steering the wormshaft 11 connected to the handle.
The sector gear 12 is lightly driven in the steering direction.

Further, a short circuit path 13 communicating with the hydraulic chambers 9 and 10 is provided within the wall thickness of the power cylinder 7, and a pulsation generating valve 14 is interposed in the middle of this short circuit path 13. The pulsation generating valve 14 is configured to be driven by a solenoid 15, to which a voltage pulse of a predetermined frequency is supplied from an oscillator 17 connected to a controller 16.

18 is a vehicle speed sensor, 19 is a steering angle sensor, 20
is a steering angular velocity sensor, which is attached to, for example, the output shaft and steering shaft of the transmission, and senses vehicle speed, steering angle, and steering angular velocity as electrical signals and inputs them to the controller 16.

FIG. 2 is a block connection diagram showing more specifically the hydraulic circuit and the electric circuit. In the same figure,
The power steering control valve 6 consists of a spool valve 6b provided in a cylinder 6a, and by selectively moving the spool valve 6b in the axial direction, the oil pumped by the pump 2 is transferred to the hydraulic chambers 9, 10 of the power cylinder 7. selectively supplied to either. Note that 9a and 10a are oil supply and discharge passages.

The pulsation generating valve 14 houses a spool valve 14b in a cylinder 14a, and is normally biased in the direction of closing the spool valve 14b by a spring 14c. It's starting to close.

A shaft 14d made of a magnetic material is integrally provided at the end of the spool valve 14b, and a solenoid 15 is disposed around the shaft 14d.

Note that an amplifier 21 is connected between the oscillator 17 and the solenoid 15 to obtain a desired solenoid drive output.

By the way, the sawing steering angle at which the wheels do not cause sideslip is determined by θ/n, where θ is the steering angle when the vehicle is running. It is selected to be a size that is not large. The controller 16 calculates and calculates n and θ/n, and uses the sawing steering angle data that does not cause sideslip, which has been experimentally determined in advance, as a reference signal, and uses this, the current vehicle speed,
A comparison calculation is made with each sensor output signal of the steering angle and steering angular velocity, a pulse with a frequency corresponding to the calculated output is output from the oscillator 18, the solenoid 15 is energized by the pulse, and the spool valve 14b of the pulsation generating valve 14 is activated. is periodically driven at the above frequency.

Next, the operation of this automatic sawing and handling device will be described.

Now, while the vehicle is running, if you operate the steering wheel to turn the vehicle to the right, the spool valve 6b of the power steering control valve 6 will be displaced according to the steering load, and the oil pumped by the pump 2 will be pumped. The oil in the hydraulic chamber 10 is pressurized into, for example, a hydraulic chamber 9 of the power cylinder 7, and the oil in the hydraulic chamber 10 is drained into a tank via the power steering control valve 6. Therefore, the power piston 8 is displaced to the right in FIG. 2, and as described above, the steering assistance of the worm shaft 11 is performed, and the turning steering is performed easily.

In this case, the vehicle speed sensor 18, steering angle sensor 19, and steering angular velocity sensor 20 output various data during this turn, and when the vehicle speed reaches a certain level and the steering angle and steering angular velocity reach a certain level, If the level exceeds that level, the controller 16 outputs a signal at a predetermined level to the oscillator 17 based on the output of comparison with reference data.
This output is a signal corresponding to the vehicle speed, steering angle, and steering angular velocity, and based on this signal, the oscillator outputs a pulse signal of a predetermined frequency n.

Therefore, the solenoid 15 is driven by the pulse, and the spool valve 14 of the pulsation generating valve 14
b is the short circuit path 13 according to the pulse frequency n.
The opening and closing operations will be performed. Therefore, when the power piston 8 is moving to the right in the power cylinder 7, the pulsation generating valve 14 short-circuits both the hydraulic chambers 9, 10 of the power cylinder 7 at the frequency n, so that the power piston 8 The retrograde or leftward movement of begins. In other words, since no steering change occurs during running when the power piston is stopped, the steering angle changes in the direction Q opposite to the previous steering direction P, as shown in FIG.

The left movement of the power piston 8 is fed back to the power steering control valve 6, causing the spool 6b to move to the right, and pressure oil is supplied into the power cylinder 7 through the passage 9a. Note that, at this time, the pulsation generating valve 14 is of course released from the short circuit.

By moving the power piston 8 to the right again, the steering direction is automatically corrected from the opposite direction Q caused by moving to the left to the desired steering direction P. In this way, the steering angle is alternately switched, and sawing steering is automatically performed during steering travel.
Note that a similar operation is performed when the vehicle turns left.

Furthermore, by arbitrarily setting the above-mentioned short circuit time, the distance in the steering direction P and the distance in the direction Q can be set at an arbitrary ratio, and in this case, the pulse signal can be converted into a pulse width modulated signal. This will be the case.

In this way, a pulse signal corresponding to the frequency n is output from the oscillator 17 based on the output of the controller 16, and the pulsation generating valve 14 is driven and controlled at this frequency n to control both the hydraulic chambers 9, 10 of the power cylinder 7.
By short-circuiting, it is possible to automatically obtain the optimum sawing steering angle of θ/n.

In addition, since this invention aims to automatically obtain an appropriate sawing steering angle, the pulsation generating valve 14 is arranged in the hydraulic circuits 3 and 4 between the hydraulic pump 2 and the power steering control valve. The same objective can also be achieved by controlling the supplied hydraulic pressure at the frequency n.

As explained in detail above, according to the present invention, a pulsation generating valve is provided in the hydraulic circuit of the power steering, which is driven by an oscillation pulse having a frequency corresponding to the vehicle speed, the steering angle, and the steering angular velocity. By making it possible to repeatedly activate and deactivate the displacement of the power piston in the power cylinder, the sawing handling effect is automatically obtained, so even ordinary drivers without special skills can avoid wheel slipping. The effect of stable steering driving is obtained, and it will be very beneficial if put into practical use.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the automatic sawing handling device of the present invention, FIG. 2 is a block connection diagram, and FIG. 3 is a diagram of the traveling locus of wheels by sawing steering. 1... Engine, 2... Hydraulic pump, 3, 4... Hydraulic circuit, 5... Power steering actuator, 6... Power steering control valve, 7... Power cylinder, 8... Power piston, 9, 10...Hydraulic chamber, 13...Short circuit,
14... Pulsation generating valve, 15... Solenoid,
16... Controller, 17... Pulse oscillator,
18...Vehicle speed sensor, 19...Steering angle sensor, 2
0...Steering angular velocity sensor.

Claims (1)

[Scope of Claims] 1. A pulsation generating valve is provided in the hydraulic circuit of the power cylinder and driven by an oscillation pulse with a frequency corresponding to the vehicle speed, steering angle, and steering angular velocity, and the pulsation generating valve is operated during steering. An automatic sawing handling device characterized in that the power piston in the power cylinder can be repeatedly displaced and stopped. 2. The pulsation generating valve is connected between oil supply and discharge passages leading to two hydraulic chambers separated by a power piston inside the power cylinder.
The automatic sawing and handling device described in Section. 3. The automatic sawing handling device according to claim 1, wherein the pulsation generating valve is connected to a hydraulic circuit connecting a hydraulic pump and a power steering control valve. 4. The automatic sawing handling device according to claim 1, wherein the pulsation generating valve is driven by a solenoid.