JPH0345254B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a variable damping force hydraulic shock absorber, which is disposed between a vehicle body such as an automobile and an axle. Prior Art Conventionally, in order to improve the riding comfort or running stability of automobiles, etc., a motor provided inside or outside the piston rod is rotated by a predetermined angle depending on the driving conditions of the automobile, etc. 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 an adjuster, and a control device for controlling this hydraulic shock absorber (hereinafter referred to as "control device") ) is known.
FIG. 1 is a block diagram showing an outline of such a conventional control device, and FIG. 2 is a sectional view showing the configuration of a hydraulic shock absorber controlled by this control device. Therefore, an overview of a conventional control device and a hydraulic shock absorber will be explained based on FIGS. 1 and 2. In Fig. 1, 1 indicates a predetermined damping force (in this conventional example, high damping force H) and a lower damping force (in this conventional example, medium damping force N and low damping force S).
2 is a selection reference signal generation circuit that receives one selection signal selected by the selection switch 1 and generates a selection reference signal according to the selection signal; A signal comparison circuit that compares the selection reference signal output from the selection reference signal generation circuit 2 with an output signal corresponding to the rotational angular position of the motor 4, which will be described later, and determines whether or not the selection reference signal and the output signal match. , 5 is a motor drive circuit that is operated in response to the mismatch or match signals output from the signal comparison circuit 3. Further, 4 is a motor driven or stopped by the motor drive circuit 5, and 6 is a motor that detects the rotational angular position of the drive shaft 4a of the motor 4 and outputs the rotational angular position of the motor 4 to the signal comparison circuit 3. This is a rotation angle position detection circuit that inputs an output signal corresponding to the rotation angle position. 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 this 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 device C having the above-described structure. That is, in FIG. 2, 9 is a cylinder filled with hydraulic fluid, and 10 is a piston rod that penetrates one end of the cylinder 9 in a sealed state and projects to the other end of the cylinder 9. 11 is a piston slidably inserted into the cylinder 9;
This piston 11 separates the inside of the cylinder 9 into two chambers, an upper liquid chamber 12 and a lower liquid chamber 13. This piston 11 is equipped with a damping force generating means 14 that generates a flow resistance to the hydraulic fluid displacing and flowing between the upper and lower liquid chambers 12 and 13. On the other hand, 15 is a generally cylindrical stud that connects the piston rod 10 and the piston 11. Inside this stud 15, there is an adjuster accommodating part 16 that accommodates the adjuster 8 for adjusting the damping force, and Through holes 17 in the axial direction are formed to communicate the interior of the adjuster accommodating portion 16 and the lower liquid chamber 13, respectively. Further, as shown in FIG. 3, in the cylindrical wall portion 15a of the stud 15, there are provided openings communicating with the upper liquid chamber 12, having mutually different opening areas and being spaced at predetermined intervals in the circumferential direction. Each orifice 1
8 and 19 are drilled. 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. Through hole 2
2, and a communication hole 23 that can selectively communicate with any one of the orifices 18, 19, . . . provided in the stud 15 is formed. The input end of the motor 4 is connected to a motor drive circuit 5 as shown in FIG. 1 via predetermined harnesses 24, 24, . It's becoming like that. According to the configuration of the control device C 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 2 that closes one open end of each of these through oil passages 25, 25.
A desired damping force can be ensured by displacing and flowing the working fluid between the upper and lower fluid chambers 12 and 13 while being subjected to resistance due to the elastic forces of the dampers 6 and 26. On the other hand, if you select an arbitrary damping force setting position, for example, the medium damping force setting position as shown in this example, and switch the changeover switch 1 depending on the driving condition of the car, etc., the selection signal from the changeover switch 1 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 in addition to the selection reference signal, this comparison circuit 3 also includes a rotation angle position detection circuit 6.
Since the rotational position detection signal indicating the current rotational angular position of the drive shaft 4a provided in the motor 4 is converted into a digital value by the signal conversion circuit 7 and inputted, these two signals are converted into this signal. The comparison circuit 3 compares the signals. 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 output from the signal comparison circuit 3 is The motor 4 continues to rotate until the signal becomes a match signal. In this way, the communication hole 23 of the adjuster 8 opens and communicates with the position of the orifice 19 provided in the stud 15 for setting the medium damping force selected by the changeover switch 1. Therefore, by bypassing a portion of the working fluid flowing between the upper and lower liquid chambers 12 and 13 through the orifice 19, the damping force generating means 14
The damping force obtained in is adjusted, and thus a medium damping force N can be obtained. Similarly, by controlling the rotation of the motor 4 and aligning the communication hole 23 provided in the adjuster 8 with the position of the orifice 18 for setting a low damping force, a low damping force can be obtained. In 3 diagrams
If the communication hole 23 is located within the region indicated by H _A , a high damping force can be obtained. By the way, the conventional control device C with such a configuration
In this case, in order to adjust the damping force of the hydraulic shock absorber T, the motor 4 that rotationally drives the regulator 8 is rotationally driven by the motor drive current supplied from the motor drive circuit 5. , change the damping force from "high" to "medium" or "low," or vice versa.
Or, even when selecting from "low" to "high", the same motor drive voltage value (for example 12V)
The motor 4 is then rotated to position the communication hole 23 provided therein at a desired orifice 18 position. However, in this type of control device,
In all cases, instead of driving and controlling the adjuster 8 at the same rotational speed and aligning the communicating hole 23 and the orifice 18 provided therewith, the adjustment Adjuster 8 (motor 4) depending on the degree of alignment accuracy required.
It is preferable to change the rotation speed of. For example, when changing the damping force from "low" or "medium" to "high" (for example, when the vehicle turns,
When you want to change the damping force of a hydraulic shock absorber installed on the opposite side of the turning direction from "low" or "medium" to "high"), and conversely, when you want to change the damping force from "high" to "medium". ” or “Low”, in the former case, the adjuster 8 (motor 4) is rotated at high speed to achieve high damping force in order to improve steering stability. Although it is necessary to quickly secure the communication hole 23 at a predetermined position in order to obtain the high damping force, in this case, the communication hole 23 is During ~
High damping force can be obtained by positioning it at any position within the area indicated by H _A , so the communication hole 2
There is no need to accurately set the position where 3 is stopped. On the other hand, in the latter case, although it is not necessary to rotate the adjuster 8 at high speed, in order to obtain a low or medium damping force, it is necessary to Since it is required to set the alignment accuracy with 18 and 19 to be high, it is necessary to rotate the adjuster 8 slowly. Purpose of the Invention The present invention has been made in view of such conventional demands, and when it is desired to set the alignment between the communication hole provided in the adjuster and the orifice with high precision, it is possible to The purpose of this invention is to propose a control device that can perform alignment with high precision, while also being able to quickly obtain a predetermined damping force when it is desired to obtain that damping force as quickly as possible. . Structure of the Invention The present invention has been made to achieve the above object. That is, in the present invention, when a high damping force value is selected, the orifice is blocked with a regulator to prevent the flow of hydraulic fluid, while when other damping force values are selected, the orifice and the communication hole of the regulator are aligned to prevent the flow of hydraulic fluid. The variable damping force type hydraulic shock absorber is equipped with a damping force variable means for adjusting the damping force by limiting the flow rate, and the damping force adjustment signal selected by the changeover switch and the rotation angle of the damping force adjustment motor that operates the regulator are provided. The damping force variable hydraulic shock absorber control device drives the motor until the adjuster reaches a predetermined damping force adjustment position by comparing the position detection signal with the damping force selected by the changeover switch. The present invention is characterized in that it includes a motor driving force conversion circuit that changes the driving voltage value of the motor to a voltage value that is larger when the damping force value is a high damping force value than when another damping force value is selected. Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. Components that are the same as those of the conventional example described above are given the same reference numerals, and redundant explanation thereof will be omitted. FIG. 4 is a block diagram including an electrical circuit, showing one embodiment of the control device according to the present invention. In Fig. 4, 1 is a damping force changeover switch, 2
is a selection reference signal generation circuit, and the output stage of this selection reference signal generation circuit 2 includes a damping force switching signal generation circuit 27 that outputs a signal for switching the damping force setting position to the intermediate damping force position when an abnormality occurs in the control circuit. It is provided. The selection reference signal generation circuit 2 operates at each of the "high", "medium" and "low" damping force setting positions H of the selector switch 1,
A low level is given to the selected input among the N and S terminals 1a, 1b, and 1c inputs, and these inputs are connected to the anti-circuit diodes D ₃ , D ₁ , D ₂ and the CR circuit for noise removal. The gates are input to one side of the NOR circuit G ₁ and the OR circuits G ₂ and G ₃ through the gates, respectively. In addition, diodes D ₄ and D ₅ are provided in the forward direction from the input end of the setting position N to the input ends of the setting positions H and S, and the contact abnormality of the changeover switch 1, which generally occurs in the open mode, can be detected by the above-mentioned It can be detected as a low level output of the circuit _G1 , and the output of the NOR circuit _G1 is input to a failure detection circuit (not shown). As the gate input on the other side of the OR circuits G ₂ and G ₃ , the output of the failure detection circuit (not shown) is given as a low level (hereinafter referred to as "0") during normal operation. Therefore, when the changeover switch 1 is set to the medium damping force setting position N, the outputs of the OR circuits G ₂ and G ₃ become high level, and each outputs a signal of "1". The B terminal has “1,
1" is input and switch 1 is set to high damping force setting position H, the output of OR circuit G ₂ becomes low level and outputs a signal "0", and the output of OR circuit G ₃ becomes high level. As a result, a signal of "1" is output, so "0, 1" are input to the A and B terminals, and when the selector switch 1 is set to the low damping force setting position S, the output of the OR circuit _G2 is It becomes high level, outputs a signal of "1", and OR circuit G ₃
Since the output becomes low level and outputs a signal of "0", "1, 0" is input to the A and B terminals. Table 1 shows these conditions as follows.

[Table] A motor drive circuit 5 is provided at the output stage of the selection reference signal generation circuit 2. This motor drive circuit 5 has a base terminal connected to the output side of the signal comparison circuit 3 via a knot circuit 30 and a first resistor _R1 , and a collector terminal connected to the power supply section 31 side via a third resistor _R3 . and a first transistor TR ₁ with its emitter terminal connected to the ground terminal 32 side, and this first transistor
A second transistor TR ₂ is connected to the collector terminal of TR 1 via the third resistor R ₃ and has an emitter terminal connected to the power supply section 31 side, and an emitter terminal is connected to the base terminal of this second transistor TR _{2 .} and connect the third resistor R ₃ and the second transistor
A third transistor TR ₃ whose base terminal is connected to the contact point with the collector terminal of TR ₂ , and whose base terminal is connected to the collector terminal of this third transistor TR ₃ via a fourth resistor R ₄ , are connected to the power supply section. 5th on the 31st side
Connect the collector terminal through the resistor R ₅ , and
The fourth motor has an emitter terminal connected to the input side of motor 4.
It consists of transistor _TR4 . Further, a motor drive force conversion circuit 33 is provided between the selection reference signal generation circuit 2 and the motor drive circuit 5.
is provided. This motor driving force conversion circuit 3
3 does not operate when the changeover switch 1 is at a predetermined damping force position (in this example, the high damping force H position), but when the changeover switch 1 is moved from the predetermined damping force position to another damping force position ( In this embodiment, when the damping force is switched to the position (medium damping force N or low damping force S), the motor drive current supplied to the motor 4 from the motor drive circuit 5 is reduced, and the motor drive current applied to the motor 4 is reduced. The voltage applied to the motor is changed (reduced from 12V to 8V, for example).The motor driving force conversion circuit 33 is connected to the terminal 1a side of the high damping force setting position H via the knot circuit 34 to the gate input on one side. Connect the terminals and set terminal 1 at low damping force setting position S.
A NAND circuit 35 with the other side gate input terminal connected to the c side, and a sixth NAND circuit 35 on the output side of this NAND circuit 35
a sixth transistor TR ₆ whose base terminal is connected to the ground terminal 36 via _the resistor R ₆ and whose emitter terminal is connected to the ground terminal ₃₆ ; and a Zener diode Z interposed between the contact point of the base terminal of the transistor _TR4 and the contact point of the base terminal of the transistor TR4. Furthermore, when a coincidence signal (a "1" signal) is output from the signal comparison circuit 3, an inertia force is generated between the output terminal of the signal comparison circuit 3 and the input terminal of the motor 4. A motor braking circuit 38 is provided which applies braking force to the motor 4 by supplying all electric power to the ground terminal 37. This motor braking circuit 38 has a not circuit 3 connected to the output side of the signal comparison circuit 3.
9 and a seventh resistor _R7, and a seventh transistor _TR7 whose emitter terminal is connected to the ground terminal 37, and whose base terminal is connected to the collector terminal of this seventh transistor _TR7 . , and an eighth transistor TR8 whose collector terminal is connected to the ground terminal 37 and the contact point of the emitter terminal of the seventh transistor _TR7 , and whose emitter terminal is connected to the input side of the motor ₄ . Next, the operation of the control device according to the present invention having the above configuration will be explained. First, when the changeover switch 1 is switched to the terminal 1a side indicating the high damping force setting position H, the selection reference signal "0, 1" corresponding to one selection signal selected by the changeover switch 1 is changed to the selection reference signal. The signal is outputted from the generation circuit 2 and inputted to the signal comparison circuit 3, and the current position of the drive shaft 4a of the motor 4 is detected by the rotation angle position detection circuit 6, and the signal comparison circuit 3 receives the current position of the drive shaft 4a of the motor 4. Since the 2-bit output signal corresponding to the signal is inputted via the signal conversion circuit 7, both signals are compared in the signal comparison circuit 3. As a result of comparing both signals in this signal comparison circuit 3, the two signals do not match, and therefore, when the output voltage from the signal comparison circuit 3 becomes low level,
This signal comparison circuit 3 outputs a signal of "0" as a motor drive signal. Therefore, since a signal of "1" is output from the NOT circuit 30 connected to the output side of the signal comparison circuit 3, the first transistor connected via the first resistor _R1 The base current of TR ₁ becomes high, and this first transistor TR ₁ is turned on. Therefore, the motor drive current from the power supply section 31 is supplied to the base terminal of the third transistor TR3 via the fifth resistor _R5 , and the motor drive current from the power supply section ₃₁ is supplied to the base terminal of the third transistor TR3.
TR ₃ is in the ON state. Therefore, the motor drive current is transferred from the power supply section 31 to this third transistor.
It passes between the emitter and collector of TR ₃ , and then the fourth
is supplied to the base terminal of _{a fourth transistor TR 4 through} a resistor R ₄ of
It becomes ON state. Therefore, the motor drive current is
The driving current is supplied to the input end of the motor ₄ through the fifth resistor R 5 and the collector-emitter of the fourth transistor TR ₄ , and the motor 4 is rotated at a constant speed with this drive current. Note that at this time, a high voltage (for example, 12V) is applied to the motor 4 as a motor drive voltage. For this reason, the drive shaft 4 of the motor 4
By a, the adjuster is rotated within the adjuster accommodating portion. The adjuster is rotated until the output signal outputted from the rotation angle position detection circuit 6 is selected by the changeover switch 1 and matches a predetermined selection reference signal by the selection reference signal generation circuit 2. When those signals match, the signal comparison circuit 3
When the output voltage from the transistor becomes high level and a signal of "1" is output from there as a motor drive signal, a motor drive signal of "0" is output from the knot circuit 30, so that the first transistor _TR1 The base current of transistor TR1 becomes low, and this first transistor _TR1 becomes OFF. Therefore, the third transistor TR ₃ and the fourth transistor TR ₄ are
It becomes OFF state. Therefore, the supply of motor drive current from the power supply unit 31 to the motor 4 is stopped,
The motor 4 stops rotating. Note that since the drive shaft 4a of the motor 4 has an inertial force, the motor 4 will continue to rotate due to the inertial force, and an electromotive force will be generated in the motor 4 due to this rotation. However, in this embodiment, a motor braking circuit 38 is provided on the input end side of the motor 4, and as a result of outputting a match signal, that is, a signal of "1" from the signal comparison circuit 3, 7th by two knot circuits 30, 39;
When the eighth transistors TR ₇ and TR ₈ are both turned on, all of the electromotive force generated in the motor 4 flows to the ground terminal 37 via the motor braking circuit 38 and is consumed there. Braking force is applied to the motor 4. Therefore, the moment the match signal "1" is output from the signal comparison circuit 3,
Rotation of the motor 4 is stopped. Therefore, the position where high damping force can be obtained (position within the area H _A in Figure 3)
Additionally, the communication hole provided in the adjuster can be stopped. Next, a case will be described in which a lower damping force S is selected from a higher damping force H. That is, when the high damping force H is selected by the changeover switch 1, the OR circuit is activated as described above.
The output signal of G ₂ is "0", the output signal of OR circuit G ₃ is "1", and the output signal of the OR circuit G ₂ becomes an output signal of "1" at the NOT circuit 34. Therefore, from the NAND circuit 35, "0"
Since the mode signal is output, the sixth transistor _TR6 is turned off. Therefore, the motor drive current from the power supply section 31 is supplied to the motor 4 through the fifth resistor R ₅ and the fourth transistor TR ₄ , so that a predetermined high voltage (for example, 12V) is applied to the motor 4. This applied voltage causes the motor 4 to rotate. On the other hand, the high damping force H is set by the changeover switch 1.
If you select low damping force S from
The output signal of G ₂ is "1", the output signal of OR circuit G ₃ is "0", and the output signal "1" of the OR circuit G ₂ is converted into an output signal of "0" by the NOT circuit 34. Become. Therefore, from the NAND circuit 35,
Since the mode signal "1" is output, the sixth transistor TR ₆ is turned on. By the way, at the initial stage when the low damping force S is selected by the changeover switch 1, the mismatch signal "0" is output from the signal comparison circuit 3.
is output as a motor drive signal, and therefore,
The first, third and fourth transistors TR ₁ , TR ₃ and TR ₄ are in the ON state. Therefore, the motor drive current from the power supply section 31 is transmitted to the fourth resistor.
The collector terminal of the sixth transistor TR _{6 is connected to the fourth resistor R 4 and the fourth transistor} through a Zener diode Z, although the base terminal of the fourth transistor TR ₄ is supplied through Since it is connected to the contact point with the base terminal of the transistor TR ₄ , the voltage between the resistor R ₄ and the base terminal of the fourth transistor TR ₄ is a predetermined value (8V in this example).
In this case, part of the motor drive current flows to the ground terminal 36 through the Zener diode Z and between the collector and emitter of the sixth transistor _TR6 . Therefore, the base voltage of the fourth resistor R ₄ to the fourth transistor TR ₄ is determined by the breakdown voltage of the Zener diode Z, and the voltage value thereof is a low voltage (for example, 8V). Therefore, motor 4
A low voltage (for example, about 8V) is applied to the input terminal of. Therefore, the motor 4 is rotated with the motor drive voltage value of 8V, so the adjuster is rotated at a lower rotational speed than when the high damping force H is selected. Therefore, the communicating hole provided in the adjuster can be aligned with the orifice position for setting a low damping force with high precision. Contrary to this case, when the selector switch 1 selects the high damping force H from the low damping force S, the mode signal output from the NAND circuit 35 is "0", and the sixth transistor TR ₆ is Since it is in the OFF state, the motor 4 is rotated even with a voltage value of 12V. Therefore, the communication hole provided in the adjuster can be quickly located at a position within the region where high damping force can be obtained (position H _A in Figure 3), so high damping force can be obtained as quickly as possible. I can do it. Effects of the Invention As is clear from the above explanation, in the present invention, when the damping force value selected by the changeover switch is a high damping force value, the drive voltage value of the motor is changed to another damping force value. Equipped with a motor drive force conversion circuit that changes the voltage value to a larger value than when it is selected, the motor rotation speed can be changed according to the damping force value, and when a high damping force value is selected, the motor rotates at high speed. This allows you to quickly close the orifice with the adjuster to ensure vehicle maneuverability.
When selecting other damping force values, the motor rotates at low speed,
The orifice and the communication hole of the adjuster can be matched more accurately, allowing highly accurate damping force adjustment.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a control circuit used in a conventional variable damping force type hydraulic shock absorber control device; Fig. 2 is a partially cutaway sectional view showing the configuration of a conventional variable damping force type hydraulic shock absorber; 3 is a sectional view taken along the line -- in FIG. 2, and FIG. 4 is a block diagram including an electrical configuration showing an embodiment of a control circuit used in a control device for a variable damping force type hydraulic shock absorber according to the present invention. . DESCRIPTION OF SYMBOLS 1... Selector 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, 33... Motor drive force conversion circuit, C... Control device for a variable damping force type hydraulic shock absorber, T... Hydraulic pressure shock absorber.

Claims (1)

[Claims] 1. When selecting a high damping force value, the orifice is blocked with a regulator to prevent the flow of hydraulic fluid, while when selecting another damping force value, the orifice and the communicating hole of the regulator are aligned to prevent the hydraulic fluid from flowing. The variable damping force type hydraulic shock absorber is equipped with a damping force variable means for adjusting the damping force by limiting the flow rate of the damping force, and the damping force adjustment signal selected by the changeover switch and the rotation of the damping force adjustment motor that operates the regulator are provided. In a control device for a variable damping force hydraulic shock absorber, which drives the motor until the adjuster reaches a predetermined damping force adjustment position by comparing the angular position detection signal with the damping force value selected by the changeover switch. Variable damping force characterized by comprising a motor driving force conversion circuit that changes the driving voltage value of the motor to a voltage value larger than when another damping force value is selected when is a high damping force value. Control device for type hydraulic shock absorber.