JPH024810B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a control device for a variable damping force hydraulic shock absorber disposed between a vehicle body such as an automobile and an axle portion. Conventionally, in order to improve the riding comfort or running stability of automobiles, etc., a motor installed inside or outside the piston rod is rotated by a predetermined angle depending on the driving conditions of the automobile, 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 rotationally controlling an adjuster, and a control device for controlling this hydraulic shock absorber are known. FIG. 1 is a block diagram of a control circuit used in such a conventional control device, 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 changeover switch for selecting one of the desired damping force setting positions (in this conventional example, each damping force setting position is divided into three categories: high, medium, and low), and 2 is a switch for selecting the desired damping force setting position. A selection reference signal generation circuit 3 receives one selection signal selected by the switch 1 and generates a selection reference signal according to the selection signal;
compares the selection reference signal output from the selection reference signal generation circuit 2 with an output signal corresponding to the rotation angle position of the motor 4 for adjusting the damping force of the hydraulic shock absorber, which will be described later, and determines these selection criteria. A signal comparison circuit 5 which determines whether a signal and an output signal do not match or match is a motor drive circuit which operates upon receiving each of the mismatch or match signals outputted from the signal comparison circuit 3. 4 is a motor driven or stopped by the motor drive circuit 5; 6 is a motor of this motor 4;
Specifically, it is a rotational angular position detector that 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. Reference numeral 7 denotes a signal conversion circuit for inputting the contact signal output from the rotation angle position detector 6 to the signal comparison circuit 3. On the other hand, T is a hydraulic shock absorber having a structure in which an adjuster 8 for adjusting damping force is rotated by the motor 4, the details of which are shown in FIGS. 2 and 3. That is, in FIG. 2, 9 is a cylinder with one end sealed filled with hydraulic fluid, and 10 is this cylinder 9.
A piston rod that extends through the piston rod with the other end sealed. A piston 11 is slidably inserted into the cylinder 9, and the 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 between the upper and lower fluid chambers 12 and 13. 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. 17 are formed respectively. Furthermore, the cylindrical wall portion 15a of the stud 15 has a third cross-sectional view taken along the - line in FIG.
As shown in the figure, orifices 18, 1 are arranged at predetermined intervals in the circumferential direction and have mutually different opening areas and communicate with the upper liquid chamber 12.
9 and 20 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, and 20 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.
is adapted to be driven by this motor drive circuit 5. Next, FIGS. 4 and 5 show a specific configuration of the rotation angle position detector 6 described above. That is, as shown in FIGS. 4 and 5, the rotational angular position detector 6 includes an insulating substrate 30, a concentric first conductive pattern 31, a second conductive pattern formed on the substrate 30, and the like. The conductive pattern 32, the common conductive pattern 33, and the first and second conductive patterns 31, 32 and the common conductive pattern 33 are slid around the center of rotation of the motor 4 (more specifically, the drive shaft 4a of the motor). It is composed of a contactor 34 in contact with the contactor 34. The first and second conductive patterns 31 and 32 are placed at the positions of the orifices 18, 19 and 20 provided in the stud 15 described above.
In order to selectively align the communicating holes 23 provided in the adjuster 8, they are formed in a predetermined shape so that different rotational position detection signals can be output. That is, the stop position of the motor 4 corresponding to the position where the communication hole 23 and each orifice 18, 19, 20 exactly match each other is determined by X, Y, and Z.
If we divide the rotation angle range of the motor 4 rotating through these positions X, Y, and Z into first, second, and third rotation angle ranges a, b, and c, then The first conductive pattern 31 corresponds to each of the first, second, third and fourth rotation angle regions a, b and c.
The first rotation angle area a is formed in an arc shape from the starting end position a ₁ to the ending position a ₂ thereof, and the second conductive pattern 32 is further away from the first conductive pattern 31 . The second rotation angle region b is also formed in an arcuate shape from the starting end position b ₁ to the final end position b ₂ at the inner position. Note that B is the first
A is the electrode of the second conductive pattern 32, C is the electrode of the common conductive pattern 33, and each of these electrodes A, B, C and the first and second
The respective conductive patterns 31, 32 and the common conductive pattern 33 are electrically connected by conductive patterns 31a, 32a, 33a whose upper portions are covered with an insulating layer. In FIG. 4, reference numeral 35 indicates a reduction gear mechanism that reduces the rotational force of the motor 4 and transmits it to the adjuster 8. However, this reduction gear mechanism 35 is not provided, and the drive shaft 4a of the motor 4 directly controls the adjuster. 8 may be rotated. Further, 37 is a harness connected to each of the electrodes A, B, and C for extracting a rotation angle position detection signal, 38 and 38 are bearings that rotatably support the drive shaft 4a, and 39 is a case. According to the configuration of the control device and hydraulic shock absorber as described above, the piston rod 10 with the piston 11
A valve plate that closes one of the through oil passages 25, 25 constituting the damping force generating means 14 provided in the piston 11 by the vertical movement of the valve plate. 26,2
The desired damping force can be ensured by displacing and flowing the working fluid between the upper and lower fluid chambers 12 and 13 while receiving resistance from the spring force of the damping member 6. On the other hand, if you select an arbitrary damping force setting position, for example, the medium damping force setting position N as shown in FIG. A selection reference signal corresponding to the signal is output from the selection reference signal generation circuit 2. This selection reference signal generation circuit 2 is connected to a signal comparison circuit 3, and this comparison circuit 3 receives, in addition to the selection reference signal, a current position of the drive shaft 4a of the motor 4 from a rotation angle position detector 6. Since the rotational position detection signal indicating the rotational angular position at is input after being converted into a digital value by the signal conversion circuit 7, these two signals are compared in this signal comparison circuit. This signal comparison circuit 3 outputs a match signal when the two signals match, and a mismatch signal when they do not match. Therefore, the motor drive circuit 5 is operated by 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 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. The orifice 19 provided in the stud 15 for setting the medium damping force selected by the changeover switch 1 in this way
Then, the communication hole 23 of the adjuster 8 is opened and communicated. For this reason, the upper and lower liquid chambers 12, 13
By bypassing a portion of the hydraulic fluid flowing through the orifice 19, the damping force obtained by the damping force generating means 14 can be adjusted to ensure a desired damping force. By the way, the contact 34 of the rotational angular position detector 6 is for detecting a rotational angle detection signal indicating the rotational angular position of the motor 4. When it is in contact with the conductive pattern 32 of No. 2, it is “1”.
If the configuration is such that a rotation angle detection signal of "0" is extracted from the electrodes A or B when the electrodes are not in contact with each other, the damping force setting position X, Y, Z of the motor 4 (5th
Table 1 shows the rotation angle detection signals obtained from each electrode A and B when the contactor 34 is located at
become that way.

[Table] In this way, different rotation angle detection signals are transmitted depending on the damping force setting positions X, Y, and Z of the contactor 34.
Since it can be detected from each electrode A, B, this rotation angle detection signal can be inputted to the signal comparison circuit 3 via the signal conversion circuit 7. Therefore, by detecting the desired rotation angle detection signal, the damping force setting position H, N,
The communicating hole 23 of the adjuster 8 can be rotated to the positions X, Y, and Z corresponding to S, so that the damping force of the hydraulic shock absorber T can be adjusted reliably and quickly. However, as described above, the rotational angle position detector 6 has a
Different rotation angle position detection signals are extracted. That is, since each conductive pattern is arranged in only one rotational angle region and there is no rotational angle region that overlaps with each other, even if the contactor 34 malfunctions, each conductive pattern 3
1 and 32 and the contactor 34 separates from these patterns 31 and 32, each rotation angle area a, b, c of the motor 4
Regardless of which region the contactor 34 is located in, signals of "0" and "0" will be taken out from each electrode A and B as a rotation angle position detection signal. Therefore, a different rotation angle position detection signal different from the regular rotation angle position detection signal is adopted as the regular rotation angle position detection signal.
This not only makes it impossible to adjust the damping force as desired, but also causes the damping force to become abnormal, resulting in unstable running of the vehicle. The present invention was proposed in view of such conventional drawbacks, and each conductive pattern is made up of two
By arranging the contacts over different rotational angle regions and having rotational angle regions that overlap with each other, it is possible to check whether the contactor is correctly contacting each conductive pattern and obtaining a regular rotational angle position detection signal. The present invention proposes a control device that can easily and reliably determine whether an abnormal rotational angle position detection signal is being obtained because the contactor is not in contact with each conductive pattern. Hereinafter, one embodiment of the present invention will be described based on the drawings. Note that the same components as those in the conventional example are given the same reference numerals, and redundant explanation thereof will be omitted. FIG. 6 shows an example of a conductive pattern of an encoder used in a rotational position detector constituting a control device according to the present invention. In this FIG. 6, 31A is an arc-shaped first conductive pattern, and at least the first conductive pattern among the first, second, and third rotation angle regions a, b, and c.
It is formed from the starting end position a ₁ of the rotation angle area a to the ending position b ₂ of the second rotation angle area b. On the other hand, 32A is an arc-shaped second conductive pattern formed at a predetermined distance from the first conductive pattern 31A, and is located at a third rotation angle from the starting end position b ₁ of the second rotation angle region b. End position c ₂ of area c
Note that 33A is a common conductive pattern, and A and B are electrodes of the first and second conductive patterns 31A and 32A. In the rotational angle position detector 6 having the conductive pattern described above, on each of the first and second conductive patterns 31A and 32A formed within the rotational angle regions a, b, c, and d of the motor 4 shown in FIG. When the contactor 34 is brought into sliding contact with the electrodes A and B, the rotation angle position detection signals obtained from each electrode A and B are as shown in Table 2.

[Table] As is clear from Table 2, the rotation angle position detection signals obtained from each electrode A and B are always signals containing "1", and therefore all bits are set to the so-called open mode. There is no such thing as
On the other hand, if a non-contact state of the contactor 34 with respect to each conductive pattern 31A, 32A occurs due to a failure of the contactor 34, the signal obtained from each electrode A, B becomes "0". ” becomes “0”. Therefore, depending on whether the signals obtained from each electrode A, B are in the so-called open mode ("0", "0"), it is possible to determine whether a failure such as poor contact of the contactor 34 has occurred. It is possible to easily and reliably determine whether the Further, since the configuration of each conductive pattern 31A, 32A is extremely simple, it is suitable for mass production. As is clear from the above description, in the present invention,
The first conductive pattern covers at least two rotation angles from the starting position of the first rotation angle area to the terminal position of the second rotation angle area among the first, second, and third rotation angle areas. formed over an area,
On the other hand, the second conductive pattern is spaced apart from the first conductive pattern by a predetermined distance, and spans two rotation angle regions from the start position of the second rotation angle region to the end position of the third rotation angle region. Moreover, since it is formed to have a rotation angle region that overlaps with the first conductive pattern, the first and second conductive patterns
When a contact is brought into sliding contact with each conductive pattern, the rotational angle position detection signal obtained from each electrode will not be detected as a so-called open mode ("0", "0"). Therefore, the so-called open mode ("0"
It can be clearly distinguished from the signal of "0"). Therefore, if the signal obtained from each electrode does not include a signal of "1" but is a signal of all "0" or "0", take appropriate measures such as immediately replacing parts such as contacts. As a result, stable running performance of the vehicle can be maintained.

[Brief explanation of drawings]

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 cross-sectional view of a main part showing the vicinity of a rotation angle position detector employed in a conventional control device, and FIG. 5 is a cross-sectional view taken along the line -- in FIG. 4. FIG. 6 is a bottom view showing an example of the conductive pattern of the rotation angle position detector used in the control device 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 detector, 8... Adjuster, 30... Insulating substrate, 31A... First conductive pattern, 32A... Second conductive pattern, S... Control circuit, T... Hydraulic pressure buffer, a... First rotation angle region,
b...Second rotation angle area, c...Third rotation angle area, _a1 , _b1 , _c1 ...Start position, _a2 , _b2 , _c2 ...Terminal position.

Claims (1)

[Claims] 1. A changeover switch for selecting a desired damping force, a selection reference signal generation circuit that receives one selection signal selected by the changeover switch and generates a selection reference signal according to the selection signal, and this selection reference signal generation circuit. The selection reference signal output from the circuit is compared with the output signal corresponding to the rotational angular position of the motor that rotationally drives the regulator for adjusting the damping force of the hydraulic shock absorber, and these selection reference signals and output signals are determined. a signal comparison circuit for determining mismatch or match; a motor drive circuit that operates in response to the mismatch or match signals output from the signal comparison circuit; and a motor driven or stopped by the motor drive circuit; Rotation drive in synchronization with the rotation of the motor on each of the arc-shaped first and second conductive patterns formed within the rotation angle region of the motor divided into three parts, first, second and third. A control device for a variable damping force type hydraulic shock absorber, comprising: a rotational angular position detector for slidingly contacting a contactor and inputting a rotational angular position signal of the contactor at a damping force setting position to the signal comparison circuit; The first conductive pattern covers two of the at least first, second, and third rotation angle regions from a starting position of the first rotation angle region to a terminal position of the second rotation angle region.
The second conductive pattern is formed over three rotation angle regions, and the second conductive pattern is spaced apart from the first conductive pattern by a predetermined distance from the starting point of the second rotation angle region to the third rotation angle region. A control device for a variable damping force type hydraulic shock absorber, characterized in that it is formed with a rotation angle region that spans two rotation angle regions up to a terminal position and overlaps with a first conductive pattern.