JPS6344562B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a control circuit for a variable damping force hydraulic shock absorber disposed between a vehicle body and an axle of an automobile, and more particularly to a circuit system that prevents complicated operations near damping force switching. . Conventionally, in order to improve the riding comfort or running stability of automobiles, etc., a motor inside or outside the piston rod is rotated by a predetermined angle depending on the driving conditions of the automobile, etc., and this rotational force is used to adjust the damping force. A variable damping force type hydraulic shock absorber that can perform desired damping force adjustment by controlling the rotation of the adjuster, and a control circuit for controlling this hydraulic pressure shock absorber (hereinafter referred to as "control circuit") ) is known. FIG. 1 is a block diagram showing an outline of such a conventional control circuit, and FIG. 2 is a sectional view showing the configuration of a hydraulic shock absorber controlled by this control circuit. Therefore, an overview of a conventional control circuit and a hydraulic shock absorber will be explained based on FIGS. 1 and 2. In FIG. 1, 1 is a switch (in this conventional example) for selecting one of the desired damping force setting positions (in this conventional example, the damping force setting positions are divided into three categories: hard, normal, and soft). 2, a switch circuit equipped with a rotary type changeover switch 1a; 2 a selection reference signal that receives one selection signal selected by the changeover switch 1 and generates a digitized selection reference circuit in accordance with the selection signal; Generation circuit 3 is this selection reference signal generation circuit 2
5 is a signal comparison circuit that compares the selection reference signal outputted from the motor 4 with an output signal corresponding to the rotation angle position of the motor 4 to be described later, and determines whether or not these selection reference signals and the output signal match. This is a motor drive circuit that is operated in response to each mismatch or match signal output from the circuit 3. 4 is a motor driven or stopped by the motor drive circuit 5; 6 detects the rotational angular position of the drive shaft 4a of the motor 4 and inputs an output signal corresponding to the rotational angular position to the signal comparison circuit 3; This is a rotation angle position detection circuit. In addition, 7 is for converting the contact signal outputted from this detection circuit 6 into a digital signal and outputting the output signal to the signal comparison circuit 3 when the rotational angle position detection circuit 6 is composed of a predetermined encoder. This is a signal conversion circuit, and is provided between the rotation angle position detection circuit 6 and the signal comparison circuit 3. The motor 4 constituting the control circuit S configured as described above operates the hydraulic shock absorber T shown in FIG.
An adjuster 8 provided at the center is rotatably driven. That is, in FIG. 2, 9 is a cylinder filled with hydraulic fluid, and 10 is a piston rod that extends through the cylinder 9, which is sealed at one end and is sealed against liquid at the other end. 11 is a piston that is slidably inserted into the cylinder 9;
1, the inside of the cylinder 9 is divided into two chambers, an upper liquid chamber 13 and a lower liquid chamber 13. This piston 11 includes the upper and lower liquid chambers 12,
A damping force generating means 14 is provided for generating flow resistance in the hydraulic fluid displacing between the damping force 13 and the hydraulic fluid displacing the hydraulic fluid. 15 is the piston rod 10 and piston 11;
This stud 15 has a generally cylindrical stud that connects the regulator accommodating section 16 and the lower liquid chamber 13. are formed respectively. Moreover, the cylindrical wall portion 15a of this stud 15
As shown in FIG. 3, orifices 18, 19, and 20, which are in open communication with the upper liquid chamber 12 and have different opening areas and are arranged at predetermined intervals in the circumferential direction, are bored. It is set up. Inside the adjuster accommodating portion 16 of the stud 15,
An adjuster 8 rotatably driven by a motor 4 housed in the hollow portion of the piston rod 10 is rotatably housed in the adjuster 8. A through hole 22 and a communicating hole 23 that can selectively communicate with any one of the orifices 18, 19 provided in the stud 15 are formed. The input end of the motor 4 is connected to a motor drive circuit 5 as shown in FIG. 1 via a predetermined number of harnesses 24, 24, . . .
It is designed to be driven by this motor drive circuit 5. According to the configuration of the control circuit S and the hydraulic shock absorber T as described above, the vertical movement of the piston rod 10 accompanied by the piston 11 causes the through oil passages 25, 25 that constitute the damping force generating means 14 provided in the piston 11 to be A valve plate 26 that closes one open end of each of these through-oil passages 25, 25,
The upper part, while being resisted by the spring force of 26;
A desired damping force can be ensured by displacing and flowing the working fluid between the lower fluid chambers 12 and 13. On the other hand, if an arbitrary damping force setting position, for example, the medium damping force setting position as shown in this example is selected depending on the driving condition of the automobile, etc., and the selector switch 1a is switched, the selection signal from the selector switch 1a is A corresponding selection reference signal is output from the selection reference signal generation circuit 2. This selection reference signal is connected to a signal comparison circuit 3, and this comparison circuit 3 includes:
In addition to the selection reference signal, a drive shaft 4a provided in the motor 4 is sent from the rotation angle position detection circuit 6.
Since the rotational position detection signal indicating the current rotational angular position is converted into a digital value by the signal conversion circuit 7 and input, these two signals are compared in the signal comparison circuit 3. In this signal comparison circuit 3, if the two signals match, a match signal is output, and if they do not match, a mismatch signal is output. Therefore,
The motor drive circuit 5 is operated by each of these signals. That is, when the match signal is input to the motor drive circuit 5, the supply of drive current from the motor drive circuit 5 to the motor 4 is stopped, and therefore the rotation of the motor 4 is stopped. . On the other hand, when a mismatch signal is input to the motor drive circuit 5, a drive current is supplied from the motor drive circuit 5 to the motor 4 in accordance with this mismatch signal, and therefore, the signal comparison circuit 3
The motor 4 continues to rotate until the output signal from the motor 4 becomes a match signal. In this way, the communication hole 23 of the adjuster 8 comes into open communication with the orifice 19 provided in the stud 15 for setting the medium damping force selected by the changeover switch 1. For this reason,
Adjusting the damping force obtained by the damping force generating means 14 by bypassing a part of the working fluid flowing between the upper and lower liquid chambers 12 and 13 through the orifice 19, A desired damping force can be ensured. In the case of the above configuration, the operating state of the control circuit S is changed by the switching operation of the changeover switch 1a that determines the damping force, but other factors that determine the damping force can be considered to be vehicle speed and vehicle height displacement. . In other words, when driving at high speeds, it is necessary to lower the vehicle height and increase the damping force of the hydraulic shock absorber to increase vehicle stability.On the other hand, when driving on rough roads and raise the vehicle height, the hydraulic shock absorber must be increased. It is required to reduce the damping force of the shock absorber. A circuit means has also been considered in which the vehicle speed and vehicle height displacement are sensed by a vehicle speed sensor and a vehicle height displacement sensor, respectively, and added to the selection reference signal generation circuit 2 to determine the damping force. For example, the factors that determine the damping force are a selector switch that selects one of three damping force setting positions: high, medium, and low, a vehicle speed signal obtained by a vehicle speed sensor, and a vehicle height displacement sensor. The damping force adjustment motor is driven by variations in each factor, which complicates the operation and causes malfunctions.
That is, if the above factors fluctuate significantly, the motor 4, which is the actuator for adjusting the damping force,
The operation becomes unstable, and malfunctions are likely to occur especially near the damping force changeover, and the changeover switch must be operated frequently in accordance with the state of the vehicle. The present invention has been made in view of the above, and includes:
The purpose of this invention is to provide a device that eliminates the various drawbacks of conventional devices, eliminates the complicated operation of the damping force changeover switch, and eliminates malfunctions near the damping force changeover, and its gist is as follows: To obtain an electronic control device for a variable damping force type hydraulic shock absorber, which is provided with a troublesome signal prevention circuit such that a switching signal is not output unless the switching signal is input for a certain period of time or more. Embodiments of the present invention will be described below with reference to FIGS. 4 and 5. First, FIG. 4 shows the entire control circuit S, and 31 is a changeover switch for the user to arbitrarily select the damping force, and this switching state is displayed on the damping force indicator light 32. . The damping force indicator light 32 is also designed to flash in order to detect failures, as will be described later. 33 is a vehicle speed sensor, 34 is a vehicle height displacement sensor, and their respective signal outputs are sent to the complicated signal cancel circuit 3 along with the output of the damping force changeover switch 31.
Enter 5. The troublesome signal cancel circuit 35 is a stage preceding the damping force selection signal generation circuit, and its structure and operation are shown in FIG. 5, and detailed explanation will be given later. 36 is a damping force selection signal generating circuit which receives the signal output from the damping force changeover switch 1, converts it into a signal corresponding to the damping force, and outputs it in 2 bits. Table 1 shows an example of the output signal.

[Table] H stands for HARD, N stands for NORMAL, and S stands for SOFT. 37 is an input signal comparison circuit, which includes a damping force selection signal generation circuit 36 and a signal level conversion circuit 38 corresponding to the rotation angle position of the motor 4, which will be described later.
Receives a signal from the device, calculates whether the latter signal matches the former signal, and outputs an “H” signal if they match, and an “L” signal if they do not match. do. 39 is a motor drive circuit;
In response to a signal from the input signal comparison circuit 37, output control is performed to drive and stop the motor 4.
It also has a function of receiving a signal from the failure detection circuit 40 and turning off the drive output to the motor 4. Reference numeral 41 denotes a damping force switching signal generation circuit, which receives the signal from the failure detection circuit 40 and operates to separate the signal from the damping force selection signal generation circuit 36. That is, when receiving a "High" signal from the failure detection circuit 40, the damping force changeover switch 31 is disconnected.
Instructs and controls the damping force to be set to the “NORMAL” position. The failure detection circuit 40 is a circuit that monitors the output signal levels of the damping force selection signal generation circuit 36 and the input signal comparison circuit 37 by time management, and when the output signal level is "High", it is stable in a steady state. “Low”
means that the switch is being changed or the motor 4 is being driven, and is in a state of being controlled toward the target value. Therefore, the "Low" time is monitored, and if it does not become "High" within a certain period of time, for example, after 3 to 4 seconds, a signal is issued as a system abnormality, and the operator turns off the ignition switch. It operates to maintain that state until Reference numeral 42 denotes an indicator light drive circuit which receives a signal from the failure detection circuit 40 and causes the damping force indicator light 32 to blink. At this time, indicator lights other than the indicator light displaying the selected damping force are made to blink. 43 is a current limiter circuit, which continuously monitors the output current of the motor drive circuit 39 for each output and prevents the output current from exceeding a certain value, for example, 300 mA,
This is to protect the drive circuit and harness in the event of an output short circuit. On the other hand, a valve position sensor 44 is attached to the motor 4, which detects the rotation angle position of the drive shaft 4a of the motor 4 and sends a 2-bit "ON-OFF" signal to the signal level conversion circuit 38.
Output as a contact signal. 45 is a valve unit that opens and closes within the variable damping force type hydraulic shock absorber. In the above circuit configuration, the troublesome signal cancel circuit 35, which is a main component of the present application, will be explained based on FIG. 5. That is, the troublesome signal cancel circuit 35 is inserted between the damping force selection switch 31 and the damping force selection signal generation circuit 36,
The circuit configuration is a gate circuit 46, a signal storage circuit 4
7, a level sense circuit 48 and a timer circuit 49. The individual circuit functions will be described below. That is, the gate circuit 46 receives the input signal from the damping force changeover switch 31, the vehicle speed signal input 33', and the vehicle height displacement signal input 34', and then outputs the signal to the signal storage circuit 47.
The purpose is to supply the respective input signals to the
The gate is turned on or off depending on the output signal of a timer circuit 49, which will be described later. The gate circuit 4
When the gate No. 6 opens, the output of the timer circuit 49 is "High". The signal storage circuit 47 reads the signal output when the gate circuit 46 is open, and transmits the signal to the damping force selection signal generation circuit 3.
6, and operates to maintain the initial signal until the gate circuit is closed and then reopened to output a new signal. The level sense circuit 48 detects the signal levels of the damping force changeover switch 31, the vehicle speed signal input 33', and the vehicle height displacement signal input 34'.For example, if the damping force changeover switch 31 is HARD,
When the damping force selector switch 31 is in the NORMAL and SOFT positions, a "Low" signal is output to the timer circuit 49, and when the damping force changeover switch 31 is in the middle of switching the above-mentioned signals, a "High" signal is output to the timer circuit 49 as well. Output. The timer circuit 49 is configured to count when the output of the level sense circuit 48 is "Low" and reset the count when the output is "High". Therefore, if the above "Low" signal output is not continuous for a certain period of time, the gate circuit 4
6, the signal for opening this will not be output. Vehicle speed signal input 3 which is another input signal
3', the same goes for the vehicle height displacement signal input 34', and the timer circuit 49 counts while the signal input maintaining a constant level continues, and if the level is fluctuating, the count is reset. Therefore, the opening and closing of the gate circuit 46 is controlled in the same manner as in the case of the damping force changeover switch 1. According to the complicated operation prevention circuit of the variable damping force type hydraulic shock absorber control device of the present invention described in detail above,
Its structural feature is that a troublesome signal cancel circuit is inserted between the signal terminal for changing the damping force of a damping force changeover switch, etc. and the damping force selection signal generation circuit, and the troublesome signal cancel circuit is fixed at a certain level. Since the circuit is configured to output only the signal that has been continuously input for a period of time or more, the following operational effects can be achieved. In other words, when a factor that changes the damping force of the hydraulic shock absorber occurs, such as when the vehicle speed fluctuates depending on the driving condition of the vehicle or due to fluctuations in the vehicle height, the damping force changeover switch is set in advance. In normal cases, the operation based on the above factors is added to the position, making the operation extremely complicated, and there is a risk that the actuator for adjusting the damping force will not be able to follow it and malfunction, or the damping force will change. Contrary to the disadvantages of having to operate the changeover switch in a complicated manner, in the case of the present invention, the changeover signal is not output unless the signal to change the damping force is continuously input for a certain period of time or more. This configuration has the great advantage that the signal to the actuator is stabilized, there is no risk of malfunction, and there is no need to perform complicated operations on the damping force changeover switch. The damping force fluctuation factors such as the vehicle speed signal or the vehicle height signal have a so-called dead zone in the middle of switching and do not operate the timer circuit, so the switching operation is stable and reliable. It is highly effective when adopted in a control device for a vehicle equipped with a variable hydraulic shock absorber.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional control circuit for a variable damping force type hydraulic shock absorber, Fig. 2 is a sectional view of main parts showing the structure of the hydraulic shock absorber, and Fig. 3 is a diagram taken along the - line in Fig. 2. 4 is a block diagram showing an embodiment of the control circuit according to the present invention, and FIG.
FIG. 3 is a block diagram showing details of the complicated signal cancel circuit shown in the figure. 31... Damping force selection switch, 33... Vehicle speed sensor, 34... Vehicle height displacement sensor, 35... Complicated signal cancel circuit, 36... Damping force selection signal generation circuit, 37... Input signal comparison circuit, 38... ...Signal level conversion circuit, 39...Motor drive circuit, 4
0... Failure detection circuit, 41... Damping force switching signal generation circuit, 43... Current limiter circuit, 44... Valve position sensor, 45... Valve unit, 46
...Gate circuit, 47...Signal storage circuit, 48...
...Level sense circuit, 49...Timer circuit.

Claims (1)

[Scope of Claims] 1. A damping force selection signal generation circuit to which a changeover switch for selecting a desired damping force is connected, and to which a vehicle speed signal and a vehicle height displacement signal are respectively input; and the damping force selection signal generation circuit. A control device that compares the selection reference signal outputted from the damping force variable hydraulic shock absorber with a rotational angle position detection signal of a damping force adjustment motor of the variable damping force type hydraulic shock absorber, and drives the motor until it reaches a predetermined damping force adjustment position. In the step before the damping force selection signal generation circuit, the damping force selection signal generating circuit receives the signal input from the changeover switch, the vehicle speed signal input, and the vehicle height displacement signal input, and is continuously input for a certain period of time or more. 1. A complicated operation prevention circuit for a control device for a variable damping force hydraulic shock absorber, characterized in that a complicated signal canceling circuit is provided to output only a signal that has been applied. 2. The troublesome signal cancel circuit includes a gate circuit that supplies the signal input from the damping force changeover switch, the vehicle speed signal input, and the vehicle height displacement signal input to the signal storage circuit, and reads the output of the gate circuit. a signal storage circuit that maintains the signal at a certain level; a level sense circuit that detects the signal levels of the damping force changeover switch, vehicle speed signal, and vehicle height displacement signal; and a level sense circuit that receives and counts the output signals of the level sense circuit, and A control device for a variable damping force hydraulic shock absorber according to claim 1, comprising a timer circuit that outputs only a count signal continuously outputted over time to the gate circuit as an opening/closing signal for the gate circuit. circuit to prevent complicated operations.