JPH0220413A - Control circuit for variable damping force type liquid-operated shock absorber - Google Patents

Abstract

PURPOSE:To precisely changeover damping forces by instituting the stop angle positions of a motor shaft indicated by the indicating means of damping force at the predetermined angles avoiding a dead band in a variable resistance type detecting means of rotational angle. CONSTITUTION:Output of a rotational angle detector 15 and an output signal from an indicating means of damping force 31 are input to a comparing means of rotational angle 30. By this comparing means 30, comparison between the target stop angle position and the actual rotational angle position is performed and a control signal is judged by a judging means of damping force changeover signal 32 based on the result. Hereby, a motor electric source supply circuit 22, a driving motor circuit 23, and a braking circuit 24 for controlled. In this case, by instituting the dead band of the variable resistance type rotational angle detector 15 in the range during changeover from a large damping force to a small damping force, accuracy of the motor stop position is improved without loss of responsibility of changeover control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application 1] The present invention relates to a control circuit for a variable damping force type hydraulic shock absorber disposed between a vehicle body and an axle of an automobile or the like.

"Prior Art" It has been known for a long time that a damping force variable hydraulic shock absorber is disposed between the body of an automobile or the like and the axle.For example,
Japanese Unexamined Patent Publication No. 59-99139 discloses that a piston rod is inserted through one end of a cylinder filled with hydraulic fluid.
A piston fixed to the piston rod separates the inside of the cylinder into both a base part and a lower liquid chamber, and the through-oil passage provided in the piston and the opening of the oil passage are closed. In order to secure the desired damping force by the action of the plate, the oil passage 1-2 is bypassed between the liquid chamber inside the piston rod that connects to the lower liquid chamber of the cylinder and the upper liquid chamber of the cylinder. , ``C'' describes a structure in which a plurality of communicating orifices with different opening areas are provided and the damping force is adjusted in multiple stages by controlling the rotation of the adjuster and opening any of the orifices. Similar damping force variable hydraulic shock absorbers are also available in Japanese Patent Application Laid-Open No. 1983
It is also described in JP-A-12325 and the like. The control circuit of the conventional variable damping force hydraulic shock absorber described in these publications includes a motor that rotationally drives the regulator, a motor drive circuit, a changeover switch that selects a desired damping force, and a motor that responds to a selection signal. It consists of a comparison means for comparing the stopped angular position and the actual rotational angular position of the motor, and a control signal based on the output of the comparison means operates the motor drive circuit j2 to rotationally drive the adjuster. In addition, the control circuit described in the above-mentioned Japanese Patent Application Laid-Open No. 59-99139 has the following characteristics:
Consumes power1. A brake circuit is provided for reliably stopping the motor at a predetermined rotational angle position by moving the motor once.

In the conventional control circuit for a variable damping force type hydraulic shock absorber, a device for detecting the rotation angle position of the damping force switching motor and a t7
encoders are commonly used.

This encoder is usually a combination of a plurality of conductive patterns provided concentrically on an insulating substrate, and a contact element that slides into contact with these conductive patterns and moves according to the rotation of the contact 1. If the shapes of the conductive patterns are different, 1. By default, the state of contact between the conductive pattern and the contactor is set to vary by 4 degrees depending on the circuit angle of the motor. Then, each drive position and stop position of the motor are set using a combination of contact and non-contact obtained from the signal line led out from the contactor.

FIG. 9 is an example of a detection signal of the motor rotation angle when an encoder is used. The horizontal axis M is the motor rotation angle, and the vertical axis is the detected value. The damping force is determined by the motor rotation angle [soft-j (S), r normal J (N) and [hard Jl
) are divided into three areas.

[Problem to be solved by the invention] In this case, since the detection value changes step by step for the three regions, for example, if the detection signal "indicates hard 1".
However, it is difficult to distinguish whether the rotation angle is at position A, position B, or position C in the figure. In this way, when an encoder is used, 1. For example, even if the desired stop position is [position 3] in the figure, there is a problem that it is not possible to confirm whether the motor is actually stopped at position 13 +hL. there were. The resolution of the encoder can be lowered by increasing the number of bits, but increasing the number of bits increases the number of encoder output lines, which increases the wiring from the suspension to the control circuit. The big problem is raw 4
It's true. It is also conceivable to use a variable resistor instead of an encoder; in this case, the resolution of motor rotation angle position detection will decrease 1, and less wiring will be required, but in general, variable resistors There is a problem in that it is not possible to continuously detect more than 360 degrees due to limitations. In addition, the rotation range of the motor is limited according to the effective angle of the variable resistor, and the motor is rotated only within a predetermined angle. If this is done, the problem arises that the motor control circuit becomes complicated.

The present invention has been made in order to solve the above-mentioned problems.The present invention improves the accuracy of detecting the rotation angle during adjustment of the damping force of a variable damping force type hydraulic shock absorber, and also improves the accuracy of detecting the rotation angle of the damping force variable hydraulic shock absorber. The aim is to improve the accuracy of

Another object of the present invention is to realize accurate detection of the rotation angle position of the rotor by using a variable resistor without using a complicated control circuit. ing.

Another object of the present invention is to obtain a control circuit for a variable damping force hydraulic shock absorber that can easily detect an abnormal state.

A further object of the present invention is to provide a control circuit for a variable damping force hydraulic shock absorber that can improve the stopping position accuracy without impairing responsiveness.

"Means for Solving the Problems" In order to achieve the above object, a control circuit for a variable damping force hydraulic shock absorber of the present invention has a rotating shaft coupled to a regulator of a variable damping force hydraulic shock absorber. a motor that adjusts the damping force of the shock absorber by driving the adjuster, a motor drive circuit that rotates the rotating shaft of the motor in only one direction, and a brake circuit that stops the rotation of the rotating shaft; damping force indicating means for selecting a damping force in the shock absorber and generating an output signal corresponding to the selected damping force; detecting a rotational angular position of the motor rotating shaft; outputting a saw according to the rotational angular position; variable resistance rotation angle detection means for generating a signal;
Comparing means compares the output signal of the rotation angle detecting means with the output signal of the damping force indicating means, and operates the motor drive circuit and the brake circuit based on the output signal of the comparison means; and a control circuit for moving the rotational angular position to a desired position. Each motor stop angle position indicated by the damping force indicating means is set to a respective rotation angle that avoids the dead zone of the variable resistor type rotation angle detecting means.

[Function] The detected value of the variable resistor type rotation angle detection means is, for example, the second
As shown in the figure, the motor rotation angle changes continuously j2 between dead zones over a wide range of 360 degrees.

For example, each motor/evening stop angle position corresponding to three levels of damping force (soft, normal, hard) is set to a predetermined rotation angle that avoids the dead zone, as shown in the figure, and rotates the motor in only one direction. Even when it is driven, the stop angle position can be detected regardless of the dead zone, and the accuracy is increased by narrowing the setting area of the valley stop angle position.

"Example] Examples will be described below based on the drawings.

FIG. 11 is an overall configuration diagram of an embodiment of a variable damping force type hydraulic shock absorber dexterity control circuit according to the present invention. As is clear from FIG. 1, this embodiment includes a motor 14 that drives the adjuster of the variable damping force type hydraulic shock absorber l to adjust the damping force, and a motor 14 that rotates in only one direction. Motor drive circuit 2
3, a brake circuit 24 for braking the motor, a motor power supply circuit 22 for supplying motor drive power to the motor drive circuit, and a damping force for the hydraulic shock absorber 1, and the damping force is applied to the selected damping force. damping force indicating means 31 for indicating the corresponding motor stop angular position; variable resistor type rotation angle detecting means 15 for detecting the rotation angular position of the motor 14;
rotation angle comparison means 30 for comparing the output signal of the rotation angle detection means 15 with the signal output from the damping force indicating means; and a control signal for controlling rotation/stopping of the motor 14 based on the output of the comparison means. a motor operation signal generation means 33 that generates and outputs it to the motor drive circuit 23; a brake operation signal generation means 34 that generates a control signal that controls activation/deactivation of the brake circuit 24; a motor supply power signal generating means 35 for generating a control signal for controlling the M source supply and outputting it to the motor power supply circuit 22;
damping force switching signal determining means 32 for determining control signals generated by each of the signal generating means 33 to 35 based on the 0 output;
and a failure detection means 36 for detecting a failure by comparing the target stop position and the detected stop position.

Further, the motor stop angle positions at which the damping force indicating means can indicate 1 hour are set at respective predetermined rotation angles that avoid the dead zone of the variable resistor type rotation angle detection means.

FIG. 3 shows the structure of the variable damping force type hydraulic shock absorber in the same embodiment. FIG. 4 is a sectional view along line AA in FIG. 3.

In this embodiment, the cylinder 2 of the hydraulic shock absorber 1 includes:
The piston rod 3 is inserted through the sealing part (not shown) on the upper line side, and the cylinder 2 is attached to the tip of the piston rod 3.
A piston 4, which is slidably inserted into the piston 4, is fixed. The inside of the cylinder 2 is divided by the piston 4 into an upper liquid chamber 5 and a lower liquid chamber 6. Further, a plurality of through passages 7 and 8 are installed in the piston 4 to connect the upper liquid chamber 5 and the lower liquid chamber 6. One of the through passages 7 has an opening on the upper liquid chamber 5 side, and an opening on the upper liquid chamber 5 side. The through passage 8 has an opening on the lower liquid chamber 6 side.
They are each elastically sealed from one direction by valve plates 1-9 and 10. These through passages 7.8 and valve bulb 1 note 9. IO+! It constitutes a damping force generating means and resists 1.5 elastic force when the piston rod 3 moves downward. The piston rod 3 functions to ensure a desired damping force by displacing and flowing the hydraulic fluid. is attached so that it can slide and rotate freely. Rotary valve! 2 is connected to two control rods 137, and is rotationally driven by the motor 14 disposed at the top. Also,
A variable resistor type rotation angle detector I5 is disposed at the connection between the rotation shaft of the motor 14 and the control [Irad 13].

Three communication holes 1617 and 18 are provided in the piston rod 3 at predetermined intervals in the circumferential direction to communicate the internal through hole 11 and the two-part liquid chamber 5 of the cylinder 2. The passage area of each communication hole 16 to 18 is equal to 1. The first communication hole 16 and the second communication hole 17 are arranged at symmetrical positions with respect to the central axis, and the third communication hole 18 is arranged in a symmetrical position with respect to the central axis. It is located between the second communication holes 16 and 17 and closer to the first communication hole 16 . Furthermore, a pair of orifices 19 and 20 are formed in the cylindrical wall of the rotary valve 12 at symmetrical positions with respect to the central axis. The rotary valve 12 is rotated by the motor I4 by one rotation and stopped at the position shown in FIG. The upper liquid chamber 5 and the internal liquid chamber 2N of the piston rod 3 are communicated through these two orifices 19 and 20. Also,
One of the two orifices 19.20 is the third communication hole 18.
Motor at the position where it opens! 4 is stopped, the F part liquid chamber 5 and the internal liquid chamber 2! are communicated by the orifice. Therefore, in this embodiment, motor 1
4 rotates 180 degrees, -L liquid chamber 5 and internal liquid chamber 2
! There are three stages of communication: communication through two orifices, communication through one orifice, and no communication through an orifice. This changes the flow rate setting of the hydraulic fluid that bypasses the through passage 7.8 of the piston 4 and switches to the required damping force.

A control circuit for controlling the rotation of the motor 14 has a configuration as shown in FIG.

In FIG. 5, 22 is a motor source supply circuit, 23 is a motor drive circuit, and 24 is a brake circuit. Motor 1
The power supply circuit 22 supplies motor drive power to the motor drive circuit 23. The motor drive circuit 23 and the brake circuit 24 are each connected to the motor 14, the motor drive circuit 23 drives the motor 14 to rotate only in one direction according to the drive signal 17, and the brake circuit 24 rotates the motor 14 by the motor inertia force. The motor is braked by consuming the electromotive force generated by the motor. Moreover, the motor 141. Second, a variable resistor type rotation angle comparing means 5 is connected. The rotation angle detector 15 is the sixth
As shown in the figure, it is composed of a positive terminal 25, negative terminals 1 and 6, a resistor 27 connected between them, a brush 28 that rotates in conjunction with the motor 14, and an output terminal 29. It is configured to be rotatable over many degrees. The variable resistor type rotation angle detector 15, in which the output voltage at the output terminal 29 changes according to the rotation of the brush 28 that is linked to the motor 14, has a dead zone every 360 cycles depending on whether the motor 14 has a large damping force or not. , it is set to be in a range between the rotational position corresponding to the small damping force and the rotational position corresponding to the small damping force. The output of the rotation angle detector 15 is input to the rotation angle comparison means 30. @The rotation angle comparison means 30 includes:
Further, the output signal of the damping force indicating means 31 is inputted. The damping force instructing means selects and instructs a target motor stop angle position according to a changeover switch for selecting a damping force and vehicle running conditions. In step 1-, the rotation angle comparison means 30 compares the target stop angle position and the actual rotation angle position, and the damping force switching signal determination means 32 determines the control signal based on the comparison result. Thereby, the motor power supply circuit 22. The motor drive circuit 23 and brake circuit 24 are also controlled. As shown in FIG. 7, when switching the damping force, the motor power supply is continuously energized until a predetermined angle before the target stop position, and the motor drive circuit is activated. and,
Continuous energization is switched to intermittent energization a predetermined angle before the target stop position. Further, the predetermined angle rotation 1
At 7, the brake circuit is activated. The timing of switching the motor power source to intermittent energization and the activation timing of the brake circuit are corrected according to the power supply voltage of the motor. In other words,
When the power supply voltage is high, the energization switching timing and the blownogi activation timing are advanced. In addition, the stop position is detected for each control, and correction is performed based on it.

The rotation angle of the motor 14 is detected at any time and compared with the target stop position. This facilitates failure detection.

Next, a flowchart for executing control in this embodiment will be explained with reference to FIG. In addition, 5110~S2!0
represents each step 1-, .

After starting, first, use 5IIO to set the target stop position of the motor according to the changeover switch and vehicle running conditions.

Next, at 5120, the supply voltage of the motor is detected;
5130, settings are made such as the range in which the power supply voltage of the motor is switched from continuous energization to intermittent energization, the range in which the power is cut off, and the range in which the switch is applied. Here, an appropriate range is determined by adding corrections based on the stop position detected for each control and the magnitude of the power supply voltage.

Next, at 5140, the rotation angle of the motor is detected, and at 5140, the rotation angle of the motor is detected.
50 to 5170, the damping force switching signal is determined.

First, in 5150, a determination is made to stop the motor.

Then, if the motor does not stop, go to 5I60,
Determine whether or not the motor is within the range where the brake is applied.

Within the range of applying the brakes (if 4, then 5170
Go to and determine whether the motor power supply is within the range of intermittent energization. If it is not within the range for intermittent energization, go to step 5180 to set the motor power supply to continuous energization and also to disable the drive circuit and brake circuit. If YES at 5170, the process goes to 5190, where the motor power supply is turned on intermittently, and the drive circuit is activated and the circuit is deactivated.

If YES at 6160 (the brake is within the range), the process goes to 5200 to cut off the motor power, stop the operation of the drive circuit, and activate the brake circuit.

Also, when it is determined in 5150 that the motor has stopped, 52
10, cut off the motor power supply j7, stop the drive circuit, and stop the operation of the main circuit.

According to this embodiment, even if the stopping position of the motor changes due to changes in the motor power supply or load, the motor power supply can be switched on and off (lower 1.< means voltage limit) and the brake circuit operation can be controlled by R. By controlling the damping force appropriately, the responsiveness and accuracy of damping force switching can be further improved.

In addition, by setting the dead zone of the variable resistor type rotation angle detection means to be in the range between switching from a large damping force to a small damping force, the motor stop position can be adjusted without impairing the responsiveness of switching control. Accuracy can be improved.

In the above embodiment, a case has been described in which the damping force is switched in three stages, but the damping force may be switched in more stages, or the spring constant of the damping force generating means may be changed at the same time. You should try to do that.

In addition, in the above embodiment, the low F of the average voltage due to intermittent energization is used to reduce the voltage applied to the motor. However, it goes without saying that similar effects can be obtained by using a circuit that linearly controls the voltage.

It is also possible to configure the motor to monitor its stop position and rotational speed at any time, and in this way abnormal conditions can be easily detected.

The present invention can be implemented in various other ways.

[Effect of the invention 1] Since the present invention is configured as described below, the rotation angle of a motor rotating in one direction can be detected accurately by using a variable resistor while avoiding a dead zone. In addition, in combination with intermittent energization (or voltage limitation) of the motor power source and control of the brake circuit, highly accurate damping force switching can be performed.

[Brief explanation of the drawing]

FIG. 1 is an overall diagram of an embodiment of a control circuit for a variable damping force type hydraulic iron according to the present invention, FIG. 2 is a characteristic diagram for explaining the present invention in detail, and FIG. 4 is a cross-sectional view of main parts showing the structure of the pressure buffer, FIG. 4 is a sectional view taken along line A-A in FIG. 3, FIG. 5 is a control circuit diagram of the same embodiment, and FIG. 6 is a rotation angle detector in the same embodiment. 7 is an explanatory diagram illustrating the control of the embodiment, FIG. 8 is a flowchart for executing the control of the embodiment, and FIG. 9 is a characteristic diagram of the prior art. l: Hydraulic shock absorber,! 4: motor, 15: variable resistor type rotation angle detector, 22 motor 1 source supply circuit, 23: motor drive circuit, 24 nib brake circuit, 30: rotation angle comparison means, 31: damping force indicating means, 32: Damping force switching signal determination means.

Claims (1)

[Claims] (1) A motor that has a rotating shaft coupled to an adjuster of a variable damping force hydraulic shock absorber, and adjusts the damping force of the shock absorber by driving the adjuster; a motor drive circuit that rotates only in the direction; a brake circuit that stops the rotation of the rotating shaft; a damping force indicating means that selects a damping force in the shock absorber and generates an output signal corresponding to the selected damping force; variable resistance type rotation angle detection means for detecting the rotation angle position of the motor rotation shaft and generating an output signal according to the rotation angle position; an output signal of the rotation angle detection means and an output signal of the damping force indicating means; a control circuit that operates the motor drive circuit and the brake circuit based on the output signal of the comparison means to move the rotational angular position of the motor rotation shaft to a desired position, A control for a variable damping force type hydraulic shock absorber, characterized in that the stop angle position of the motor rotating shaft indicated by the means is set at a respective predetermined rotation angle that avoids a dead zone of the variable resistor type rotation angle detection means. circuit.