JPH0421211B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rotation angle position control device for a motor for a variable damping force type 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, etc., and this rotational force is used to adjust the damping force. By controlling the rotation of the adjuster,
2. Description of the Related Art Variable damping force hydraulic shock absorbers capable of adjusting desired damping force and control devices for controlling the hydraulic shock absorbers 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, the damping force setting positions are divided into three categories: high, medium, and low), and 2 is this changeover switch. A selection reference signal generation circuit receives one selection signal selected by 1 and generates a selection reference signal in accordance with the selection signal; 3 represents a selection reference signal output from the selection reference signal generation circuit 2 and a motor to be described later. A signal comparison circuit 5 compares the output signals corresponding to the rotation angle positions of 4 and determines whether these selection reference signals and output signals match or match; This is a motor drive circuit that operates in response to signals. 4 is a motor that is driven or stopped by the motor drive circuit 5; 6 is a motor that detects the rotational angular position of the drive shaft 4a of the motor 4, and the signal comparison circuit 3 corresponds to the rotational angular position of the motor 4; This is a rotation angle position detection circuit that inputs the output signal. In addition, when this rotational angle position detection circuit 6 is constituted by a predetermined encoder, a signal conversion circuit 7 is provided for converting the contact signal outputted from this detection circuit 6 into a digital signal and inputting it to the signal comparison circuit 3. must be provided between the rotation angle position detection circuit 6 and the signal comparison circuit 3. T is a hydraulic shock absorber having a structure in which an adjuster 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 filled with hydraulic fluid and sealed at one end, and 10 is a piston rod that extends through the cylinder 9 in a sealed state at the other end. 1
1 is a piston that is slidably inserted into the cylinder 9, and this piston 11 allows the inside of the cylinder 9 to be divided into an upper liquid chamber 12 and a lower liquid chamber 1.
It is divided into two rooms, 3 and 3. This piston 11
is equipped with a damping force generating means 14 for creating a flow resistance in the hydraulic fluid displacing between the upper and lower fluid chambers 12 and 13. 15 is the piston rod 10 and piston 11;
The stud 15 has a cylindrical shape as a whole and connects the adjuster accommodating section 1.
6 and an axial through hole 17 that communicates the interior of the adjuster accommodating portion 16 and the lower liquid chamber 13 are formed, respectively. Further, the cylindrical wall portion 15a of the stud 15 has a second
As shown in FIG. 3, which is a cross-sectional view taken along the - line in the figure, the tubes are arranged at predetermined intervals in the circumferential direction and have mutually different opening areas and communicate with the upper liquid chamber 12. Each orifice 18, 19, 20
is 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, and the adjuster 8 has an axial passage that opens and communicates with the lower liquid chamber 13. Hole 22
A communication hole 23 is formed which can selectively communicate with this through hole 22 and any one of the orifices 18, 19, and 20 provided in the stud 15. The input end of the motor 4 is connected to a predetermined harness 2.
As shown in FIG. 1, the motor 4 is connected to a motor drive circuit 5 via terminals 4 and 24, and the motor 4 is driven by the motor drive circuit 5.
14 is a damping force generating means, and the damping force generating means 14 closes oil passages 25, 25 that communicate the upper liquid chamber 12 and the lower liquid chamber 13, and the upper and lower opening ends of these oil passages 25, 25. Valve plates 26, 26,
The valve seat 3 is arranged on the stud 15 at the upper and lower parts of the valve plates 26, 26.
0, 31, and a washer 3 inserted between the valve seats 30, 31 and the valve plates 26, 26.
2,33. According to the configuration of the control circuit 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, when an arbitrary damping force setting position, for example, the medium damping force setting position as shown in FIG. A selection reference signal corresponding to the selection reference signal generation circuit 2 is outputted 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 receives the current rotational angular position of the drive shaft 4a of the motor 4 from a rotational angular position detection circuit 6. Since the rotational position detection signal shown in FIG. 1 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, so that the output signals from the signal comparison circuit 3 match. The motor 4 continues to rotate until the signal is received. In this way, the communication hole 23 of the adjuster 8 opens and communicates with 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 hydraulic fluid flowing between the upper and lower liquid chambers 12 and 13 through the orifice 19, the damping force obtained by the damping force generating means 14 is adjusted. A desired damping force can be ensured. A specific example of the rotational angle position detection circuit 6 forming a part of the control circuit having the above configuration will be described with reference to FIG. In other words, the figure shows an example of a conductive pattern constituting a normal encoder.
A conductive pattern 31, a second conductive pattern 32, and a common conductive pattern 33 are formed concentrically, and a contact 34 extends from the center point 0 to cover each of the patterns. The contactor 34 rotates while sliding on each pattern by the rotational driving force of the motor 4 with the rotation center at . A is an electrode of the first conductive pattern 31, B is an electrode of the second conductive pattern 32, and C is an electrode of the common conductive pattern 33. Now, adjust the rotation area of the contact to a, according to the shape of each conductive pattern.
Consider dividing it into four areas b, c, and d. Table 1 shows the signals obtained at electrodes A and B when the contactor 34 is in contact with the first or second conductive pattern as "1" and the non-contact is as "0". .

[Table] That is, by using the signal obtained based on Table 1 above as the rotation angle detection signal of the motor 4, the damping force of the hydraulic shock absorber can be adjusted. However, when using an encoder with the above configuration, it is configured to extract different signals depending on the contact or non-contact state of each conductive pattern and the contact, so if the brush attached to the contact does not malfunction. If the contact condition with the conductive pattern becomes poor due to the fault, or if a disconnection or short circuit occurs in the harness, the signals obtained from electrodes A and B will no longer be normal signals, and this signal may be affected by the fault. It has the disadvantage that it is difficult to determine whether the signal was generated by an accident or is an original normal signal. Therefore, since the signal generated due to the failure is used as is as a normal signal, there is a problem in that the damping force adjustment becomes abnormal and the vehicle running performance deteriorates. The present invention has been proposed in view of the above-mentioned conventional drawbacks, and provides a rotational angular position of the motor that can detect a failure mode of disconnection or short circuit based on the above-mentioned reasons when the slider and the conductive pattern are in contact with each other. The purpose is to provide a control device, and its gist is that, as a rotational angle position detection device, a contactor that rotates in synchronization with the rotation of an adjuster, and a concentric ring that is in contact with the contactor are used. a first conductive pattern and a second conductive pattern formed in the contactor, a means for supplying power to the contact, a slit-shaped cutting portion provided at a plurality of locations in the first conductive pattern and the second conductive pattern, and the slit a fixed resistor provided to connect a selected arbitrary cut part in the shaped cut part;
It is characterized by consisting of a pair of output terminals derived from arbitrary parts of the first conductive pattern and the second conductive pattern, and resistors having the same standard value, one of which is connected to the output terminal, and the other of which is grounded. An object of the present invention is to obtain a rotation angle position control device for a motor for a variable damping force type hydraulic shock absorber. Embodiments of the present invention will be described in detail below with reference to the drawings.
FIG. 5 shows an example of a conductive pattern of an encoder used in a rotation angle position control device according to the present invention, and FIG. 6 is a side sectional view of a device including the same pattern. That is, a first conductive pattern 42 and a second conductive pattern 43 are formed concentrically on an insulating substrate 41, and a power supply pattern 44 is similarly formed concentrically inside the first and second conductive patterns 42, 43. be done. The first conductive pattern 42 is provided with a plurality of slit-like cut portions 42a, 42b, and the second conductive pattern 43 is similarly provided with a plurality of slit-like cut portions 43a, 43b. A fixed resistor R is attached to connect the cut portions of portions 42b and 43b. A is first
B is an electrode of the conductive pattern 42, B is an electrode of the second conductive pattern 43, and C is an electrode of the power supply pattern 44. 45 is a contact which is fixed to the drive shaft 4a of the motor 4 and rotates in synchronization with the rotation of the drive shaft to connect the conductive patterns 42, 43, 4.
4. Slide and move on the top. 46 is a gearbox that transmits the rotational force of the motor 4, 47 is a signal output harness for the encoder, 48 is a bearing for the drive shaft 4a, and 49 is a case. FIG. 7 shows a rotational angular position detection circuit including the encoder. In the same figure, 50 is shown in FIG.
The main body of the encoder explained in FIG. 6,
Connect the power supply +E to electrode C, and connect electrode A and electrode B.
A pair of output terminals a and b are derived from this.
Ra and Rb are resistors, one of which is connected to output terminals a and b, and the other of which is grounded.
Low antibodies with the same standard values for Ra and Rb are used. Reference numerals 51 and 52 indicate terminals connected to a controller not shown. In the above configuration, A, B, and B shown in FIG.
Table 2 shows the potentials obtained at the output terminals a and b when the contactor 45 is located in each of the four regions C and D.

[Table] That is, the power source E, the potential, and the potential determined by the fixed resistor R and the resistors R _a and R _b are output to the output terminals a and b. Moreover, by setting the resistance R _a = R _b , E・R _a /(R+R _a )=E・R _b /(R
+R _b ), Table 2 can be displayed using only two types of signals after all. Therefore, assuming that the contact 45 rotates counterclockwise, as the rotation range of the contact 45 changes from A, B, C, and D, the output terminals a and b will have the values shown in Table 2. Since two types of signals are generated sequentially, these signals can be used as the rotation angle detection signal of the motor 4. The control circuit for using the above detection signal as a signal for adjusting the damping force of the hydraulic shock absorber and the configuration of the hydraulic shock absorber controlled by this control circuit are shown in FIGS. 1 and 2. Since it is the same as the conventional configuration example, duplication of explanation will be avoided. The encoder configuration of the above embodiment does not have a so-called open mode, in which the conductive pattern and the contact are always in contact and dissociate, so there is no possibility that the conductive pattern and the contact will be disconnected due to unforeseen circumstances such as wire breakage. When a contact state occurs, a signal completely different from the signal value shown in Table 2 will be generated, and a situation such as a failure can be easily detected. Furthermore, as an example of a rotation angle position detection circuit using the above encoder, as shown in FIG. 7, a configuration is provided in which electrodes A and B and terminals a and b are connected to ground via resistors R _a and R _b , respectively. Therefore, when an abnormal signal occurs due to a short circuit between conductive patterns, an excessive current flows through the resistors R _a and R _b , and a signal completely different from the signal value shown in Table 2 is generated. Failures such as short circuits can be easily detected. Note that the power supply pattern 44 is not limited to that illustrated, and other power supply means may be used as long as it is capable of applying a power supply potential to the contactor 45. In the present invention described above, the conductive patterns constituting the encoder are improved, and the first conductive pattern and the second conductive pattern are formed concentrically so as to be in contact with a rotating contactor that is synchronized with the rotation of the regulator. a conductive pattern, a means for supplying power to the contact, a slit-shaped cut section provided at a plurality of locations in the first conductive pattern and the second conductive pattern, and an arbitrary cut selected in the slit-shaped cut section. The main component is a fixed resistor provided to connect the parts, and when such an encoder is combined with a rotary drive device for the adjuster, various practical effects described below can be achieved. In other words, when an abnormal signal occurs due to disconnection or short circuit of the harness during use, it is difficult to determine whether the signal obtained from each electrode is due to a failure of the brush attached to the contactor, or whether it is an original normal signal. It is possible to clarify whether there is Therefore, there is no risk that a signal generated due to a failure will be directly adopted as a normal signal, and it is possible to prevent the damping force adjustment from becoming defective. Furthermore, if an abnormal signal occurs, appropriate measures such as parts replacement or repair can be taken immediately, which is extremely effective in ensuring vehicle running performance. It is effective when adopted as a rotation angle position control device for a shock absorber motor.

[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 plan view of a conductive pattern showing an example of an encoder of a rotational angular position control device employed in a conventional device, and FIG. 5 is a conductive pattern showing an example of a rotational angular position detection device according to the present invention. A plan view, FIG. 6 is a side sectional view showing a part of the device, and FIG. 7 shows an example of a detection circuit for the rotational angular position. 41... Insulating substrate, 42... First conductive pattern, 43... Second conductive pattern, 42a, 42
b, 43a, 43b...slit-shaped cut portion, 44
...Power supply pattern, 45...Contact, R...Fixed resistance, a, b...Output terminal, Ra, Rb...Resistor (same standard).

Claims (1)

[Scope of Claims] 1. A method for moving any one of a plurality of orifices having different diameters to a predetermined rotational angle position, which are rotatably arranged in a passage communicating between liquid chambers separated inside the hydraulic shock absorber. a rotary angular position detection device that outputs an output signal corresponding to the rotary angular position of the adjuster; a selection reference signal corresponding to the selected damping force mode; A rotary angular position control device for a motor for a variable damping force hydraulic shock absorber, comprising a rotary drive device that is driven or stopped depending on a discrepancy or coincidence with an output signal of a rotary angular position detection device and rotationally drives the adjuster. The rotation angle position detection device includes a contact that rotates in synchronization with the rotation of the adjuster, a first conductive pattern and a second conductive pattern that are formed concentrically so as to be in contact with the contact, and Connecting means for supplying power to the contact, slit-like cut portions provided at a plurality of locations in the first conductive pattern and the second conductive pattern, and selected arbitrary cut portions in the slit-like cut portions. a fixed resistor provided in the first conductive pattern and a pair of output terminals derived from arbitrary parts of the first conductive pattern and the second conductive pattern, each having the same standard value, one of which is connected to the output terminal and the other of which is grounded. 1. A rotation angle position control device for a motor for a variable damping force hydraulic shock absorber, comprising a resistor.