JPH0224371Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is based on the normal state of the correspondence relationship between the steering wheel steering angle and the state of the steering actuator, that is, the deviation between the steering wheel steering angle and the actual steering angle of the wheels in a fully hydraulic power steering system. The present invention relates to a correction device for detecting and correcting misalignment between a handle and an actuator, and more particularly to a misalignment correction device for detecting misalignment between corresponding predetermined positions of a handle and an actuator and aligning the predetermined positions of both.

Fully hydraulic power steering systems have been known that eliminate the need for a mechanical link between the steering wheel and the actuator. This caused a deviation in the actual steering angle, making it practically impossible to use it as it was except for special vehicles. Therefore, it is conceivable to add and use a device for correcting the above-mentioned deviation, but depending on the correction method, the entire structure becomes complicated and expensive, which is impractical. In addition, many of them can only be used with limited types of all-hydraulic power steering devices.

Therefore, the present invention provides a modification that detects the misalignment between the corresponding predetermined positions of the handle and the actuator using two sensors, and based on this detects the misalignment between the handle and the actuator, and controls the actuator using a simple control means to eliminate the misalignment. The purpose is to provide equipment.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a directional control valve 3 and a metering unit, ie, a hydraulic motor 4, are operated by rotation of a steering shaft 2 caused by a steering operation of a handle 1. As shown in FIG. The valve 3 is a 6-port 3-position switching valve, and one of the two ports that is open at the intermediate position in FIG. It is connected to the reservoir 8 via 7. Two of the four ports are closed in the intermediate position.
They are connected to the left and right ports of the metering unit 4 via oil passages 9 and 10, respectively, and the other two are connected to the left and right ports of the metering unit 4, respectively.
It is connected to left and right chambers 14 and 15 of a cylinder 13, which is an actuator for front wheel steering, via oil passages 11 and 12. In the left position in FIG. 1, the valve 3 communicates between the oil passage 5 and the oil passage 9, the oil passage 7 and the oil passage 11, and the oil passage 10 and the oil passage 12, and in the right position, the oil passage 5 and the oil passage 10, oil passage 7 and oil passage 12, oil passage 9 and oil passage 11
communicate with each other.

On the other hand, the steering shaft 2 is provided with a switch 17 that is turned on and off when the steering wheel 1 is at a neutral position where it is not turned to the right or left, and the piston rod 18 is provided with a switch 17 that is turned on or off when the steering wheel 1 is in a neutral position where the steering wheel 1 is not turned to the right or left. Correspondingly, a switch 20 is provided which is turned on and off from a neutral position where the piston portion 19 of the piston rod 18 takes a central position within the cylinder 13.

Signals from both switches 17 and 20 are sent to the control circuit 2.
1 is input. The control circuit 21 controls the correction solenoid valve 22 based on this input signal. The valve 22 is a 3-port, 3-position switching valve that forms part of a control means for changing the control state of the cylinder 13 by the handle 1. In the intermediate position, all three ports are closed and the upper solenoid 23
In the lower position taken when is in the excited state, the oil passage 11
An oil passage 25 branching from the oil passage 25 and an oil passage 26 branching from the oil passage 5 are connected to the throttle 27 and the check valve 28.
In the upper position taken when the lower solenoid 24 is in the excited state, the oil passage 29 branched from the oil passage 12 and the oil passage 2
6 communicate with each other via the throttle 27 and check valve 28 to form a bypass circuit. That is, the misalignment correcting solenoid valve 22 is provided between the left and right ports of the cylinder 13.

The manner in which the solenoid valve 22 is controlled by the control circuit 21 is as follows.

When the neutral positions of the handle 1 and the cylinder 13 are not shifted, turning the handle 1 to the left or right turns both switches 17 and 20 simultaneously OFF or ON, and in this case, the control circuit 21 switches both solenoids 23, 24 in a demagnetized state. Therefore, the valve 22 assumes an intermediate position and the oil metered by the metering unit 4 is completely transferred to the oil line 2.
Valve 3, oil passage 11, without escaping via 5, 29.
12 into the cylinder chambers 14, 15, and the control state of the cylinder 13 by the handle 1 is maintained in the normal state.

When the handle 1 is shifted to the left relative to the cylinder 13, by turning the handle 1 to the right, the switch 20 on the cylinder 13 side will turn from OFF to ON before the switch 17 on the handle 1 side when passing the neutral position. At this time, the control circuit 21 processes this signal using a simple logic circuit and uses a timer circuit to turn on the upper solenoid 23 for a certain period of time, for example, 0.5 seconds. Then, oil passage 2 branched from oil passage 11.
5. A bypass circuit is established through the check valve 28, the throttle 27, and the oil passage 26 branched from the oil passage 5. Therefore, at this time, when the handle 1 is turned to the right and the valve 3 is in the position on the right side in Figure 1, the oil is flowing in the direction of the solid line arrow in Figure 1, but it is flowing through the valve 3. A portion of the metered oil in the passage 11 escapes to the supply oil passage 5 via the conductive bypass circuit, and the remainder enters the left cylinder chamber 14 via the oil passage 11. In other words, this produces the same effect as if the internal leakage of the metering section was increased, and the handle 1 is removed from the cylinder 13.
With respect to the amount of rightward movement of the inner piston portion 19, the handle 1 is rotated to the right by a larger angle than in the normal state, and control is performed in a direction in which the above-mentioned leftward deviation of the handle 1 is eliminated.

On the other hand, when the handle 1 is shifted to the right relative to the cylinder 13, when the handle 1 is turned to the left, the switch 20 is switched to the switch 17 when passing the neutral position.
The control circuit 21, which was previously turned from ON to OFF and input this signal, turns on the lower solenoid 24 for a certain period of time. Then, the oil passage 29 branched from the oil passage 12, the check valve 28, and the throttle 2
7 is connected, and part of the metered oil in the oil passage 12, which is flowing in the direction of the dashed arrow in FIG. Control is performed in such a direction that the amount of leftward rotation of the handle 1 becomes larger than the normal state with respect to the amount of leftward movement of the piston portion 19, and the rightward deviation is eliminated.

As is clear from the above operation description, the oil passage through which the oil escapes is the supply oil passage 5 of the pump 6, and the oil only flows out from the left and right oil passages 11 and 12 of the cylinder 13, so there is only one check valve. The direction of flow of oil that can be easily escaped by simply providing it is unidirectional.

By repeating such minute corrections, the alignment of the neutral position between the handle 1 and the cylinder 13 is maintained, and the correspondence between the handle 1 and the cylinder 13 is controlled so as not to deviate from the normal state.

Note that even if the handle 1 is suddenly turned in the opposite direction after the correction valve 22 is opened in the upper or lower position, the check valve 28 remains in the bypass circuit.
Since it is equipped with a , oil will not flow in the opposite direction through the bypass circuit and no problems will occur.

Also: Even if a failure occurs in the electrical system, if a centering spring is inserted into the valve 22, the correction valve 22 will return to the intermediate position and be locked here. Therefore, even if the valve 22 is turned to the upper or lower position, the internal leakage will only increase a little due to the presence of the throttle 27, and there will be no problem with vehicle operation. Even if it disappears, it will only cause a deviation due to a somewhat large internal leakage, and there will be no problem with emergency steering.
Safety is also ensured in the event of a failure.

Next, another example of the vehicle steering angle sensor will be explained with reference to FIGS. 2 to 6.

FIG. 2 shows the link layout of the steering wheel 31, with a photoelectric sensor 3 at the end of the cylinder 13.
2 is installed. As shown in the enlarged view of FIG. 3, the rod 18 has a matte mark 33 formed by chemical conversion treatment or the like, and only a small amount of light emitted from a light emitting element 34 such as an LED is reflected on this mark 33. Therefore, the input of light to the photoelectric element 35 becomes smaller, and the future output current decreases.
This allows the center position of the rod 18 to be detected.

4th view around the kingpin seen from in front of the steering wheel 31
The figure shows a rotary sensor 37 mounted coaxially with the king pin 36. One of these structures is shown in FIGS. 5 and 6, respectively.
In the one shown in FIG. 5, a conductor 38 is pasted on a rotating disk 60 of a rotary sensor 37, and the neutral position of the wheel 31 is determined by turning ON and OFF by contacting and non-contacting the conductor 38 and the brush 39. To detect. In the one shown in FIG. 6, a slit 41 is provided in a rotating disk 40, and a light emitting element such as an LDD and a light receiving element are installed on the front and back sides of the disk 40, respectively, and when the slit 41 passes between the two elements, A light receiving element receives light from a light emitting element and detects a neutral position.

By the way, in the above embodiment, the predetermined position for correcting the deviation is the neutral position, but it is preferable to use the neutral position because the passage frequency increases and the opportunity for deviation correction increases accordingly, but the predetermined position may be any position.

As described above, according to the present invention, the first and second sensors are used to detect the predetermined positions of each of the handle and the actuator, and then the control means compares the detection results to detect the position of the handle. The all-hydraulic power rudder has a relatively simple configuration in which the deviation between the steering angle and the actual turning angle of the wheels is detected, and if a deviation is detected, the control means controls the hydraulic motor appropriately. It is possible to achieve a misalignment correction device for the taking device. Furthermore, the bypass circuit in the control means is also branched from the respective oil passages that connect to the left and right ports that communicate with the left and right chambers of the actuator, making it easy to manage the bypass circuit in a fully hydraulic power steering system. A deviation correction device can be realized.

[Brief explanation of the drawing]

Fig. 1 is a structural explanatory diagram of an embodiment of the present invention, Fig. 2 is a diagram illustrating a modification of the wheel steering angle sensor, Fig. 3 is a partially enlarged view of Fig. 2, and Fig. 4 is a wheel steering angle sensor. FIG. 5 is a partially enlarged view of one type of modification of FIG. 4, and FIG. 6 is a diagram explaining another modification of FIG. 4.
FIG. 7 is a partially enlarged view of another type of modification of the figure. Explanation of symbols of main parts, power cylinder...1
3. Handle...1, Sensor...17,20,3
2, 37, control means...22, power cylinder oil line...11, 12, high pressure oil line...5.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. By sending oil in an amount proportional to the rotation angle of a handle rotating around a steering shaft from a hydraulic motor to a wheel steering actuator via a switching valve to operate the actuator. , a fully hydraulic power steering device for steering a vehicle, comprising: a first sensor that detects a predetermined position of a handle with respect to the steering shaft; and an actuator that corresponds to the predetermined position detected by the first sensor. a second sensor for detecting a predetermined position in the operating direction; detecting a deviation between these predetermined positions based on each predetermined position detected by the first and second sensors; A control means for correcting the deviation by controlling oil supply from the hydraulic motor to the actuator in accordance with the changeover in a fully hydraulic power steering system, wherein the control means corrects the deviation by controlling oil supply from the hydraulic motor to the actuator according to the switching a bypass circuit branching from each oil passage connecting the valve and the left and right ports of the actuator; a correction valve connected to the bypass circuit; a return circuit connected to the correction valve; and a second sensor,
A control circuit for controlling the correction valve in response to detection of a deviation between each of the predetermined positions. A deviation correction device in a fully hydraulic power steering system. 2. The device according to claim 1, wherein the return circuit is connected to a high-pressure oil line that sends oil from a hydraulic pump to the hydraulic motor. 3. The actuator includes a cylinder portion having left and right chambers connected to the left and right ports, and a piston portion movable in the cylinder portion in the operating direction, and the predetermined position detected by the first sensor is: A neutral position of the steering wheel corresponding to a state where the rotation angle about the steering shaft is zero, and a predetermined position detected by the second sensor is a position corresponding to a state where the actual steering angle of the wheel is zero. Further, the piston portion is in a neutral position at a center position within the cylinder portion, and the control means operates the correction valve to conduct the bypass circuit when the control circuit detects a deviation. The apparatus according to claim 2, wherein the hydraulic motor is controlled so that the handle can rotate toward a neutral position without operating the actuator. .