JPS5997339A - Control circuit for hydraulic buffer of variable damping force - Google Patents

Abstract

PURPOSE:To enable checks about snapping and a short circuit, by improving a switch circuit for selecting a desired damping force, to convert a switch signal into an electric analogue quantity so that only three electric wires are needed for a motor regardless of the number of selectable damping forces. CONSTITUTION:When a changeover switch 1a is connected to an input terminal 32b, a contact signal is changed into a signal of a voltage determined by the ratio of the sum of resistances 31a, 31b to the resultant value of resistances 33b, 31c. The signal of the voltage is applied to a signal comparison circuit 3, which also receives an analogue signal corresponding to the present position of driving oil 4a. The circuit 3 compares both the signals with each other. If the circuit 3 is sending out an uncoincidentness signal, a driving current is supplied from a motor driving circuit 5 to a motor 4 until the compared signals coincide with each other. At that time, an adjuster provided for a hydraulic buffer T is turned to obtain a desired damping force. According to this constitution, only three electric wires for power supply, common terminal and control signal, respectively, are needed regardless of the number of selectable damping forces.

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 such as an automobile and an axle.

Conventionally, in order to improve the ride comfort or running stability of automobiles, etc., a motor inside or outside the histone rod is rotated by a predetermined angle in response to the driving conditions of the automobile, etc., and this rotational force is used to train the damping force. A variable damping force type hydraulic shock absorber capable of adjusting the desired damping force A by controlling the rotation of the adjusting A armature, and a control circuit for controlling the hydraulic shock absorber (hereinafter referred to as ""controlcircuit") is known. FIG. 1 is a block diagram showing an overview 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.

Next, the conventional control circuit and the operation of the hydraulic pressure reducing WJ device will be explained based on FIGS. 1 and 2.

In FIG. 1, 1 is a switch (in this conventional example) for selecting all of the desired damping force setting positions (in this conventional example, each damping force setting position divided into three categories: high, medium, and low). In the following, a switch circuit equipped with a rotary one-way type changeover switch 1a, 2 receives a selection signal of the circuit selected by this changeover switch 1 and generates a digitized selection reference signal in accordance with the selection signal. A selection reference signal generation circuit 3 compares the selection reference signal outputted from the selection reference signal generation circuit 2 with an output signal corresponding to the rotation angle position of the motor 4, which will be described later, and determines the selection reference signal and output. A signal comparison circuit 5 which determines whether the signals match or match is a motor drive circuit that is operated in response to each signal that is output from the signal comparison circuit 3 and indicates a match or match.

Reference numeral 4 denotes a motor that is driven, excited or stopped by the motor drive circuit 5, and 6 detects the rotational angular position of the drive shaft 4a of this motor 4 and supplies an output signal corresponding to the rotational angular position to the signal comparison circuit 3. This is a rotational angle position detection circuit that inputs In addition, 7 is for converting the contact No. 1d outputted from this detection circuit 6 into a digital signal and outputting the output signal to the signal comparison circuit 3 when the rotation angle position detection circuit 6 is composed of a predetermined encoder. This signal conversion circuit is provided between the rotation angle position detection circuit 6 and the signal comparison circuit 3.

A regulator 8 provided in a hydraulic shock absorber T shown in FIG. 2 is rotatably driven by the motor 4 constituting the control circuit s having the above-described configuration.

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 has one end sealed and the other end of which is sealed against liquid. Reference numeral 11 denotes a piston that is slidably inserted into the cylinder/cylinder 9, and the interior of the cylinder 9 is divided into two parts: an upper liquid chamber 12 and a lower liquid chamber 13. There is. This piston IIJC has the upper and lower liquid chambers 1
A damping force generating means 14 is provided for applying flow resistance to the hydraulic fluid displacing between 2 and 13.

Reference numeral 15 denotes a generally cylindrical stud that connects the piston condo 1o and the tobiston 11, and this stud 15
Inside, there is an A adjuster accommodating section 16 and an adjuster accommodating section 16.
an axial through hole 17 that communicates between the inside and the lower liquid chamber 13;
are formed respectively. Further, as shown in FIG.
Orifices 18 are arranged at predetermined intervals in the circumferential direction and have mutually different opening areas and are in communication with each other.
, 19 and 20 are drilled.

An adjuster 8 is rotatably accommodated in the adjuster accommodating portion 16 of the stud 15 and is rotatably driven by a motor 4 housed in a hollow portion of the piston rod tO. , an axial through hole 22 that opens and communicates with the lower liquid chamber 13, and one of the through hole 22 and the valley orifices 18, 19 provided in the stud 15 is selectively selected. A communication hole that allows communication is formed respectively.

The input end of the motor 4 is connected to a number of harnesses 24,
As shown in FIG. 1, the motor 4 is connected to a motor drive circuit 5 via 24, and is 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 1° accompanied by the piston 11 causes the One of the passages 25, 25 is closed at one open end of each of the through oil passages 25, 25, and the upper and lower portions are subjected to resistance due to the spring force of the pulp plates 26, 26. A desired damping force can be ensured by displacing and flowing the working fluid between the respective fluid chambers 12 and 13.

On the other hand, depending on the driving conditions of the vehicle, etc., the damping force can be set at any arbitrary damping force setting position, for example, the medium damping force setting position lIt as shown in this example.
When the selector switch 1 is selected, a selection reference signal corresponding to the selection signal from the selector switch 1 is outputted from the selection reference signal generation circuit 2. This selection criterion signal is
It is connected to the signal comparison circuit 3, and this comparison circuit 3
In addition to the selection reference signal, a rotational position detection signal indicating the current rotational angular position of the drive shaft 4a provided in the motor 4 is digitalized by the signal conversion circuit 7 from the rotational angle hidden position detection circuit 6. Since the signals are converted into values and inputted, 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 exactly match, a mismatch signal is output. Therefore, the motor drive circuit 5 is activated by each of these signals. That is, when the coincidence 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,
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 5
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 is brought into open communication with the orifice 19 provided in the stud 15 for the medium damping force setting selected by the switching switch 1. For this reason, each of the upper and lower liquid formations 12,
By bypassing a portion of the hydraulic fluid flowing through the orifice 13, the damping force obtained by the damping force generating means 14 can be adjusted to a desired damping force. can be secured.

By the way, as mentioned above, the regulator 8 provided in the hydraulic buffer 4T is rotationally driven by the motor 4 that constitutes the control circuit, but the origin of the rotation control of the motor 4 is The number of no-nes between a certain switch circuit 1 and the selection reference signal generation circuit 2, and between the rotational angle position detection circuit 6 that detects the rotational position of the motor 4 and the selection reference signal generation circuit 2 are as follows. Since the signal transmitted between the two is a digital signal, in the past, the number of harnesses for which damping force can be set (in the conventional example shown in Fig. 1, a total of three harnesses, cylinder, middle, and low) is used. Including the harness for the common line, four harnesses were required. Therefore, when increasing the number of fixed parts for which damping force can be set, the number of harnesses 24, 24, etc. It is necessary to increase the number of wires, which increases the size of the entire device, and has the drawback that inspection for disconnections or short circuits in each harness 24, 24, etc. cannot be easily and quickly performed.

The present invention has been made in view of these conventional drawbacks, and improves the switch circuit that selects the desired damping force 1 to convert the voltage of the switch -+S into an analog electrical quantity. As a result, the number of harness wires to the motor can be reduced to three, regardless of the number of damping forces that can be set, and therefore inspection of harness @ wires and short circuits can be done easily and quickly. It is something.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Components that are the same as those of the prior art example described above are given the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 4 shows an embodiment of the control circuit according to the present invention.

As shown in FIG. 4, on the input side of the signal comparison circuit 3,
A switch circuit 1 and a rotation angle position detection circuit 6 are connected, and the output end of the signal comparison circuit 3 is connected to a motor 4 via a motor drive circuit 5.

The switch circuit 1 includes a switch 1a that selects a desired damping force, and a "rolling pressure level" that converts a plurality of contact signals selected by the changeover switch 1a into different voltage level signals and outputs them to a signal comparison circuit 3. It consists of a converting section after which a voltage level signal corresponding to the selected position of the changeover switch 1a can be obtained. The voltage level converter 28 includes a plurality of first, second, third, . . . resistors 31 a , 31 b , 310 connected in series between a power supply terminal 29 and a common terminal 30 of the power supply section.
. . . and each of these first, second, third, etc. resistors 31
Connection point P between a, 31 b, 31 c...
The first, second,
Each of the third input terminals 32a, 3211.32
It is composed of c...

The input terminals 32a, 32b, 32c...
. and each of the connection points Pl m "2 e PS . . . as shown in this embodiment, 1st, 2nd, .

33 Q... is placed. Therefore, the changeover switch 1a is sequentially connected to the second and third input terminals starting from the first input terminal 32a.
When switching to each input terminal 32b, 32c,..., the first, second,... with respect to the resistance value of the first resistor 31a
Each of the resistors 33a, 33b-... and the first and second resistors 33a, 33b-...
, third . . . each resistor 31a.

Since the voltage value obtained from the connection point P is determined by the ratio of the combined resistance value obtained from the resistance values of 31 b and 31 (!...), as shown in FIG. It is possible to stamp voltages having different voltage values in stages to the output terminal 34 in accordance with the selection switching position to the terminals 32a, 32b, . . . .

In this embodiment, in order to perform analog control, the rotational angle position detection circuit 6 is configured with an analog sensor such as an a-difference resistance element 5, and the analog signal output from this detection circuit 6 is directly input to the signal comparison circuit 3. It is entered at the end.

Next, the operation of the control circuit according to the present invention having the above configuration will be explained.

First, one input terminal corresponding to a predetermined damping force setting position (for example, the second input terminal as shown in FIG.
When connected to the input terminal 32b), a contact signal obtained by the connection is transmitted to each of the first and second resistors 31a, 3 connected in series between the power supply terminal 29 and the connection point P2.
11), the resistance value of the resistance 331) between the connection point P and the second input terminal 32b, and the resistance of the resistance 31Q... between the connection point P and the common terminal 30. It is converted into a voltage level signal with a voltage value determined by the ratio of the combined resistance value obtained by the value, and is sent to the signal comparison circuit 3 via the output terminal 34.
(Outputted to Utl. The current position of one sounding shaft 4a of the motor 4 is detected by the rotational angle position detection circuit 6, and an analog signal corresponding to that position is input to this signal comparison circuit 3. Therefore, both signals are compared in the signal comparison circuit 3.

In the signal comparison circuit 3, as a result of comparing both signals, if the two signals do not match, and therefore, a mismatch signal is output from the signal comparison circuit 3, the motor is operated until both signals match. A motor drive magnetic current is supplied from the -1 drive circuit 5 to the motor, and the motor 4 is rotationally driven. [7] Therefore, the damping element provided in the hydraulic shock absorber T is rotationally driven in a predetermined direction, and desired damping force adjustment is performed.

Next, set the changeover switch 1a to the freeze 3 input terminal 32C, for example.
Similarly to the above case, selector switch 1
The damping force can be adjusted in accordance with the selected position a.

However, in this case, unlike the case where the changeover switch 1a is switched to the second input terminal 32b, as shown in FIG. Since a voltage level signal with a voltage value lower than the hydraulic pressure value of the direct pressure level signal is output from the switch circuit 1, the rotation angle position detection circuit 6 outputs a voltage level signal with a voltage value lower than the hydraulic pressure value of the direct pressure level signal. The motor 4 is driven to rotate until the hydraulic pressure values of the analog signals match. Therefore, the depletion force can be adjusted in accordance with the voltage level signal output from the switch circuit 1.

As described above, according to this embodiment, when the changeover switch la is selected, a voltage level signal corresponding to the selected state of the switch la can be outputted from the voltage level converter 28, which is different from the conventional voltage level converter 28. As shown in Figure 1, in addition to the harness for the common Wli°A child, a harness with adjustable damping force (in the conventional example shown in Figure 1, there are three: high, medium, and low) is required. , the number of harnesses wired from the switch circuit 1 and the rotational angle position detection circuit 6 to the signal comparison circuit 3 is determined by ``for the tunnel, for the common terminal, and for the common terminal. Only three lines can be used for control signals.

In the embodiment shown in FIG. 4, a case is described in which a digital switch (for example, a rotary switch) is used as the changeover switch 1a, but the present invention is not limited to this, and each input terminal 32 & , 321).

Turn each transistor on and off as a switch
It is also possible to have the user create one.

As is clear from the above description, the present invention includes a switch circuit that includes a switch that selects a desired damping force f, and a contact signal obtained by this switch that is converted into a voltage level signal and selectively output to a signal comparison circuit. The damping force can be set by adjusting the number of wires in the harness between the switch circuit and the signal comparison circuit, and between the comparison circuit and the rotational position detection circuit. Na1
Regardless of the number of wires, only three wires can be used: one for the bowl source, one for the common terminal, and one for the control signal. Therefore,
In addition to being able to reduce the size of the entire device, there is an advantage that inspection for disconnections and short circuits in the harnesses between the respective circuits can be easily and quickly performed.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the control circuit for a conventional variable damping force type hydraulic shock absorber, and Fig. 2 is a block diagram showing the entire configuration of the hydraulic shock absorber.
The top view, Figure 3 is a sectional view taken along the ■-IN line in Figure 2, and Figure 4 is
The figure is a block diagram of a concrete electric circuit configuration showing one fourteenth embodiment of the output circuit according to the present invention, and FIG. 5 is a diagram showing the voltage value when the switch is changed. DESCRIPTION OF SYMBOLS 1...Switch circuit, 1a...Switch, 2...Selection reference signal generation circuit, 3...Signal comparison circuit, 4...
Motor, 5... Motor drive circuit, 6... Rotation angle position detection circuit, 8... Adjuster, 9... Cylinder,
10... Piston rod, 11... Piston, 12
... Upper i-chamber, 13... Lower liquid chamber, 14... Damping force generating means, 15... Stud, 28... Voltage level converter.

Claims (1)

[Claims] (1) A switch for selecting a desired damping force, one selection signal selected by this switch, and an output signal corresponding to the rotational angular position of the motor are compared, and a discrepancy between these selection signals and output signals is determined. Or a signal comparison circuit that determines a match, and each mismatch or match signal output from this signal comparison circuit? a motor drive circuit that is operated in response to the
It consists of a motor that is driven or stopped by this motor drive circuit, and a rotational angular position detection circuit that detects the rotational angular position of this motor and inputs an output signal corresponding to the rotational angular position to the signal comparison circuit. , actuation''
ti, a cylindrical shape that interconnects a removable piston rod that extends through one end of a fully filled cylinder under liquid-tight sealing and a piston that is separated from each other in each of the liquid chambers in the upper and lower parts of the cylinder; An OJ provided in the piston between the upper and lower valley traps by rotating an adjuster rotatably housed inside the stud with the motor;
In a control circuit for a variable damping force hydraulic shock absorber configured to adjust the flow amount of hydraulic fluid displacing through a clamping force generating means, the switch circuit is configured to include a switch for selecting a desired damping force; A voltage level converter converts the contact signal obtained by this switch into a voltage level signal and selectively outputs it to the signal comparison circuit. A control circuit for a variable damping force type hydraulic shock absorber.