JPH04340321A - Fail safe circuit of actuator - Google Patents

Abstract

PURPOSE:To stop the power supply to an actuator in the case that a large current flows to an actuator, that the actuator does not rotate, or that the rotation of the actuator does not end within a predetermined time. CONSTITUTION:This is constituted so as to stop power supply 800 in the case that an overcurrent flows to an actuator, or in the case that rotation fat occurs in the actuator by providing it with a current detector 300, which detects the current flowing to the actuator, an overcurrent detector 400, and a rotation fault detector 500.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a fail-safe circuit for an actuator that stops power supply when an abnormality occurs in the actuator. For example, if an abnormality occurs in an actuator that changes the suspension hardness of a vehicle, it is necessary to immediately stop the supply of power.

0003

2. Description of the Related Art Here, as an example of an actuator, an actuator for a variable characteristic suspension for a vehicle is shown.

[0004] Depending on the driving conditions of the vehicle and the condition of the road surface,
Dual-mode suspensions that change the stiffness of the suspension have been proposed. Such a suspension includes a cylinder having an upper piston chamber and a lower piston chamber therein, a piston rod that is slidably movable within the cylinder and has a communication passage that communicates the upper piston chamber and the lower piston chamber. The rotary valve is configured to change the cross-sectional area of the communication passage by changing the rotation angle of a control rod inserted into the piston rod using an actuator.

[0005] Therefore, when the actuator changeover switch is switched, the rotary valve rotates and the amount of oil flowing through the communication passage in the cylinder changes, thereby changing the characteristics of the suspension.

A conventional example will be explained with reference to FIGS. 6 to 8. FIG. 6 is a longitudinal cross-sectional view of the actuator, FIG. 7 is a cross-sectional view of the actuator, and FIG. 8 is a schematic explanatory diagram of the actuator and the variable characteristic suspension. 6 is a sectional view taken along the line XX' shown in FIG. 7, and FIG. 7 is a sectional view taken along the line Y-Y' shown in FIG. 6.

In FIGS. 6 and 7, a flat motor 2 is fixed inside a case 1 with a rotation stopper pin 3. As shown in FIG. The output shaft 4 of the flat motor 2 is connected to a planetary gear reduction mechanism 5. The planetary gear reduction mechanism 5 includes upper planetary gears 5-, which are connected to each other at the central axis.
1, a lower planetary gear 5-2, a fixed internal gear 6, and a rotating internal gear 9. Further, the fixed internal gear 6 is fixed to the boss of the case 1 with a fixing screw 8. Therefore, the rotation of the motor output shaft 4 is transmitted to the plurality of upper planetary gears 5-1, so that the rotation of the motor output shaft 4 is transmitted to the upper planetary gears 5-1.
1 revolves around the fixed internal gear 6 while rotating. The rotational motion of the lower planetary gear 5-2, which is rotating together with the rotation of the upper planetary gear 5-1, is transmitted to the rotating internal gear 9. In this way, the rotation of the flat motor 2 is decelerated by the rotation and revolution of the planetary gear, and is transmitted to the actuator output shaft 10 connected to the rotary internal gear 9.

[0008] Also, on the rotating peripheral side of the rotating internal gear 9, there is a
A light reflecting plate 11 is provided, and this light reflecting plate 11
Light emitting and receiving devices 14 for detecting the rotational position are arranged on the fixed side opposite to, for example, at 90 degree intervals. The light emitting and receiving device 14 includes a light emitting element and a light receiving element (not shown). Furthermore, the light emitting/receiving device 14 is shown in FIG.
As shown in the figure, it is attached to a base plate 13 provided in a slit 12 between the case 1 and the fixed internal gear 6.

Actuator 15 configured in this way
The output shaft 10 of the suspension 1 is connected to the suspension 1 as shown in FIG.
6 control rod 17.

Now, if it is desired to switch the stiffness mode of the suspension 16, the mode of a mode indicating device (not shown) is switched to the desired mode, for example, from hard mode to soft mode. As a result, the flat motor 2 rotates, and the rotating internal gear 9 on which the light reflecting plate 11 is provided
At the position rotated by 90 degrees, the light emitting and receiving device 14 and the light reflecting plate 11 face each other, so that the light emitted from the light emitting and receiving device 14 hits the light reflecting plate 11, and the reflected light is transmitted to the light emitting and receiving device 1.
The light is received by the No. 4 light receiving element. The detection signal detected by the light receiving element causes the flat motor 2 to stop at this position. The rotation of the flat motor 2 during this time is transmitted to the planetary gear reduction mechanism 5 and further transmitted from the actuator output shaft 10 to the control rod 17 (see FIG. 8). Accordingly, a rotary valve (not shown) fixed to control rod 17 is rotated through an angle of 90 degrees and stopped, changing the oil pressure within suspension 16 and changing the stiffness characteristics of suspension 16. Furthermore, if an instruction is given to switch the mode, a 90 degree rotation will occur and the device will stop.

In the above description, the reference numeral 11 is a light reflecting plate and the reference numeral 14 is a light projecting/receiving device. However, the reference numeral 11 may be a magnet and the reference numeral 14 may be a Hall effect element. In this case, when the rotary internal gear 9 rotates and the magnet 11 reaches the position where the Hall effect element 14 is present, the Hall effect element will generate a detection output.

0012

For example, if an abnormality occurs in the above-mentioned variable characteristic suspension actuator for a vehicle, there is a risk that the suspension characteristics may change during driving.

The present invention is applicable when a large current flows through the actuator due to a short circuit, when the actuator does not rotate even if a rotation command is given, and within a predetermined time from the time when the rotation command is given. The purpose of this invention is to promptly stop the power supply to the actuator when the rotation of the actuator does not end within a certain period of time.

[0014]

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention.

In the figure, 100 is a DC power supply, 200 is an actuator control circuit, 300 is a current detection section, and 400 is a current detection section.
is an overcurrent detection section, 500 is a rotation failure detection section, 600
is a rotation start detection unit, 700 is a rotation end detection unit, 80
0 represents a power supply stop section.

The current detection section 300 detects the current flowing through the actuator and outputs a voltage corresponding to the magnitude of the current.

The overcurrent detection section 400 detects and outputs whether the output of the current detection section 300 is equal to or greater than a predetermined value V1.

The rotation failure detection unit 500 detects a change in the output of the current detection unit 300 from a value larger than a predetermined value V2 to a value equal to or less than the value V2 within a predetermined time after a rotation command signal is generated for the actuator. It detects whether or not there is a change, and outputs a signal indicating an abnormality when there is no change.

The rotation start detection unit 600 detects a change in the output of the current detection unit from a value smaller than a predetermined value V3 to a value equal to or higher than the value V3 within a predetermined period T1 after the rotation command signal for the actuator is generated. It detects whether or not there is a change, and outputs a signal indicating an abnormality when there is no change.

[0020] The rotation end detection unit 700 detects when the output of the current detection unit 300 changes from a value smaller than a predetermined value V3 to a value equal to or higher than the predetermined value V3, and before a predetermined time T2 has elapsed from that point. , detects whether the output of the current detection section 300 changes to the value V3 or less, and outputs a signal indicating an abnormality when there is no change.

The power supply stop section 800 is configured so that the overcurrent detection section detects that the output of the current detection section is at a predetermined value V1.
When the above is output, or when the rotation failure detection section 500, rotation start detection section 600, or rotation end detection section 700 outputs a signal indicating an abnormality, the power supply to the actuator is stopped.

[0022]

[Operation] When an overcurrent flows through the actuator, the overcurrent detection section 400 detects it and outputs a notification to that effect to the power supply stop section 800. Then, the power supply stop section 80
0 stops power supply to the actuator.

[0023] When the actuator does not start rotating within a predetermined time T1 after receiving the rotation command signal,
Since the output of the current detection section 300 does not increase, the rotation start detection section 600 outputs a signal indicating an abnormality to the power supply stop section 800.

When the actuator does not end its rotation within a predetermined time T2 after it starts rotating, the rotation end detection section 700 detects this and outputs a signal indicating an abnormality to the power supply stop section 800. .

[0025] Furthermore, there are cases in which the actuator does not start rotating within a predetermined time T1 after receiving the rotation command signal, and cases in which the actuator does not finish rotating within a predetermined time T2 after starting rotation. In either case, the rotation failure detection section 500 outputs a signal indicating an abnormality to the power supply stop section 800. This is because in any of the above cases, the output of the current detection section 300 does not change from a value larger than the predetermined value V2 to a value equal to or less than the predetermined value V2.

Therefore, when an abnormality occurs in the rotation of the actuator, a signal indicating the abnormality is output from the rotation start detection section 600, the rotation end detection section 700, or the rotation failure detection section 500, and the power supply stop section 800 receives this signal. to stop power supply to the actuator.

Furthermore, a combination of the rotation start detection section 600 and the rotation end detection section 700 and the rotation failure detection section 500
have the same function, so you only need to have one or the other.

[0028]

Embodiment FIG. 2 shows a first embodiment of the present invention, and FIG. 3 shows a time chart of the first embodiment. In FIG. 2, 100, 200,
300, 400, 500, and 800 correspond to FIG.

In the current detection section 300, a current flowing through the actuator control circuit is detected by a detection resistor r1, and the voltage appearing at the detection resistor r1 is amplified by an operational amplifier A1 and output.

In the overcurrent detection section 400, the output of the current detection section 300 is compared with a reference voltage V1 by an operational amplifier A3, and when the output is higher than the reference voltage V1, a logic value "1" is output.

In the rotation failure detection section 500, the operational amplifier A2 detects whether the output of the current detection section 300 is higher or lower than the reference voltage V2, and when the output is higher or lower than the reference voltage V2, a logic value "1" is set at point b, and when it is low, the logic value is set to "0". appears. Also, b
When the value of the point changes from "1" to "0", the value "1" is added to point d.
” appears. The rotation command signal is a one-shot multivibrator 51 and R-S flip-flops F, F1 52
is input. One shot multi vibrator 51
The output -Q is a predetermined time T3 from the rotation command signal.
It remains "0" until the above-mentioned time T3 has elapsed, and becomes "1" when the above-mentioned time T3 has passed. Further, the output Q of the R-S flip-flop becomes "1" in response to the rotation command signal, and becomes "0" when the reset input is input. The output -Q of the one-shot multivibrator 51 and the output Q of the R-S flip-flop 52 are connected to a power supply stop section 80 via an AND circuit 53.
Therefore, if the reset signal is not input to the R-S flip-flop 52 while the output -Q of the one-shot multivibrator 51 is "0", the rotation failure detection unit 500 outputs "1". Output.

In the power supply stop section 800, when there is an input from the overcurrent detection section 400 or the rotation failure detection section 500 to the reset R-S flip-flop 81, the transistor 82 is turned off and the electromagnetic switch 83 is turned off.
to open.

FIG. 3 shows a time chart of the first embodiment. Figure 3a is normal, Figure 3b is when a large current flows, Figure 3c is
FIG. 3d shows a case where the rotation does not end even if a rotation command is given, and FIG. 3d shows a case where the rotation does not end within a certain period of time.

■ is the rotation command signal, ■ is the potential at point a, ■ is the potential at point b, and ■ is the set input of the flip-flop 52.
■ is the reset input of the flip-flop 52, ■ is the Q output of the flip-flop 52, ■ is the output of the one-shot multivibrator, ■ is the set input of the flip-flop 81, ■ is the -Q output of the flip-flop 81, (10) is It shows the potential at point c.

Normally, when a rotation command is issued, the actuator starts operating, so the potential at point a rises and the value at point b becomes "1". Also flip flop 5
The Q output of the one-shot multivibrator 51 also becomes "1", and the -Q output of the one-shot multivibrator 51 becomes "0". After a while, the operation of the actuator is completed, the values at points a and b decrease, a reset input is input to the flip-flop 52, and the Q output of the flip-flop 52 becomes "0". Furthermore, when the predetermined time T3 has elapsed, the -Q output of the one-shot multivibrator 51 becomes "1", but at this time, the output Q of the flip-flop 52 is "0", so the set input of the flip-flop 81 There isn't. Therefore, the -Q output of the flip-flop 81 remains at "1".

When a large current flows through the actuator that has started operating in response to a rotation command, the potential at point a becomes higher than the reference voltage V1, and c
The value of the point becomes "1" and power supply is stopped. If the rotation command does not occur even if a rotation command is given, the potential at point a does not rise, so naturally the value at point b remains "0". Therefore, the reset input of the flip-flop 52 caused by the change of the value at point b from "0" to "1" is not input, so the Q output of the flip-flop 52 is "1".
It remains as it is. Therefore, when the time T3 has elapsed, the -Q output of the one-shot multivibrator 51 changes from "0" to "1", the set input of the flip-flop 81 is input, and the power supply is stopped.

[0037] If the rotation does not end within the fixed time T3, the value at point b remains "1" even after the time T3 has elapsed.
Therefore, the output of the flip-flop 52, which became "1" due to the rotation command, also remains "1". Then, since the -Q output of the one-shot multivibrator 51 changes from "0" to "1", the set input of the flip-flop 81 is input, the power supply is stopped, and the actuator is stopped.

FIG. 4 shows Example 2 of the present invention, and FIG. 5 shows Example 2.
The time chart is shown below.

In FIG. 4, 100, 200, 300,
400, 600, 700, and 800 correspond to FIG. Current detection section 300, overcurrent detection section 400
The operation is similar to that in FIG.

The operation of the rotation start detection section 600 will be explained. In the operational amplifier A2, the potential at point a is the reference voltage V
2. It detects whether it is higher or lower than 2, and outputs a logic value "1" to point b when it is high, and "0" when it is low. The one-shot multivibrator 61 changes the output from -Q to "0" only during a certain period of time T1 after the rotation command signal is input.
Output. In the R-S flip-flop 62, the rotation command signal causes the output Q to become "1", and the reset signal from the operational amplifier A2 causes the output Q to become "0". Therefore, if the reset signal is not generated within a certain period T1 from the rotation command signal, both inputs of the AND circuit 63 become "1", and the rotation start detection section 600 outputs "1".

The operation of the rotation end detection section 700 will be explained. In the D flip-flop 71, the value of the input D is "
1", the value of clock input CK is output as output Q. In the counter 72, a reset signal is input to the reset terminal R as the potential at point b falls, and after input of the reset signal, the number of pulses input to the clock input CK is greater than a predetermined number n. When it becomes larger, "1" is output from the output Qn.

FIG. 5 shows a time chart of the second embodiment. Figure 5a is normal, Figure 5b is when a large current flows, Figure 5c is
5d shows a case where the rotation does not end even if a rotation command is given, and FIG. 5d shows a case where the rotation does not end within a certain period of time. ■ is the rotation command signal, ■ is the potential at point a, ■ is the potential at point b, ■ is the input of flip-flop 62, and ■ is the flip-flop 62
The output, ■ is the - of the one-shot multivibrator 61
Q output, ■ is the clock pulse, ■ is the Q output of the D flip-flop 71, ■ is the Qn output of the counter 72, (10)
is the reset input of the counter 72, (11) is the set input of the flip-flop 81, (12) is the Q output of the flip-flop 81, and (13) is the potential at point c.

Normally, when a rotation command is issued, the actuator starts operating, so the potential at point a rises and the value at point b becomes "1". Further, the Q output of the flip-flop 62 becomes "1" by the rotation command signal and becomes "0" by the reset signal from point b. The -Q output of the one-shot multivibrator 61 becomes "0" only for a predetermined time Tn from the rotation command signal, and returns to "1" after the elapse of the predetermined time. Therefore, if the output of the flip-flop 62 and the output of the one-shot multivibrator 61 become "1" at the same time, the output of the rotation start detection section 600 becomes "1".
do not become. The output Q of the D flip-flop 71 outputs the value of the clock input when the potential at point b is "1", and if the number of output pulses is within a predetermined number, the output of the counter 72 is "1". '', the counter 72 is reset by the potential drop at point b.

When a large current flows, the potential at point a becomes the reference voltage V1 and "1" is output at point c, so the output of the flip-flop 81 becomes "1" and goes to the actuator control circuit 200. power supply will be stopped.

[0045] If it does not rotate even if a rotation command is given,
The output of the flip-flop 62 is maintained for a certain period of time T from the rotation command.
Even after n passes, the output of the one-shot multivibrator 61 does not return from "1" to "0", so the output of the one-shot multivibrator 61 changes from "0" to "1".
'', a set signal is input to the flip-flop 81, and the power supply is stopped.

[0046] If the rotation does not end within a certain time,
Since the count value of the counter 72 exceeds a predetermined value and the Qn output of the counter 72 becomes "1", the power supply is stopped.

[0047]

As described above, according to the present invention, when the actuator does not operate normally, the power supply to the actuator can be immediately stopped to prevent accidents due to malfunction of the actuator.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle configuration of the present invention.

FIG. 2 is a diagram showing Example 1 of the present invention.

FIG. 3a is a diagram showing a time chart (normal time) of the first embodiment.

FIG. 3b is a diagram showing a time chart of Example 1 (when a large current flows).

FIG. 3c is a diagram showing a time chart of Example 1 (when the rotation is not performed even if a rotation command is given);

FIG. 3d is a diagram showing a time chart of Example 1 (when rotation does not end within a certain period of time).

FIG. 4 is a diagram showing Example 2 of the present invention.

FIG. 5a is a diagram showing a time chart (normal time) of Example 2;

FIG. 5b is a diagram showing a time chart of Example 2 (when a large current flows).

FIG. 5c is a diagram illustrating a time chart of Example 2 (when rotation does not occur even if a rotation command is given);

FIG. 5d is a diagram showing a time chart of Example 2 (when rotation does not end within a certain period of time).

FIG. 6 is a longitudinal cross-sectional view of the actuator.

FIG. 7 is a cross-sectional view of the actuator.

FIG. 8 is a schematic illustration of an actuator and a variable characteristic suspension.

[Explanation of symbols]

100 DC power supply 200 Actuator control circuit 300 Current detection section 400 Overcurrent detection section 500 Malfunction detection part 600 Rotation start detection part 700 Rotation end detection part 800 Power supply stop part

Claims (2)

[Claims] 1. In a fail-safe circuit for an actuator that stops power supply when an abnormality occurs in the actuator, a current detection unit that detects a current flowing through the actuator and outputs a voltage corresponding to the magnitude of the current; An overcurrent detection section detects and outputs whether the output of the current detection section is equal to or greater than a predetermined value V1, and when a rotation command signal to the actuator is generated, within a predetermined period T3 from that time. After the output of the current detection section reaches a value larger than a predetermined value V2, it is detected whether or not there is a change from the value V2 to a value equal to or less than the value V2, and when there is no change, a signal indicating an abnormality is generated. It includes a rotation failure detection section that outputs an output, and a power supply stop section, and when the overcurrent detection section outputs that the output of the current detection section is greater than or equal to a predetermined value, Alternatively, a fail-safe circuit for an actuator is characterized in that the power supply to the actuator is stopped when the rotation failure detection section outputs a signal indicating an abnormality. 2. In a fail-safe circuit for an actuator that stops power supply when an abnormality occurs in the actuator, a current detection unit that detects a current flowing through the actuator and outputs a voltage corresponding to the magnitude of the current; An overcurrent detection section detects and outputs whether the output of the current detection section is equal to or higher than a predetermined value V1, and current detection is performed within a predetermined period T1 after the rotation command signal to the actuator is generated. a rotation start detection section that detects whether or not there is a change in the output of the section from a value smaller than a predetermined value V3 to the value V3 or more, and outputs a signal indicating an abnormality when there is no change; When the output of the detection section changes from a value smaller than a predetermined value V3 to the value V3 or more, the output of the current detection section decreases to below the value V3 before a predetermined time T2 elapses from that point. Detect whether there has been a change,
It includes a rotation end detection section that outputs a signal indicating an abnormality when there is no such change, and a power supply stop section, and the power supply stop section is configured such that the overcurrent detection section detects that the output of the current detection section is predetermined. When outputting that the value is greater than or equal to the value V1,
Alternatively, a fail-safe circuit for an actuator is characterized in that the power supply to the actuator is stopped when the rotation start detection section or the rotation end detection section outputs a signal indicating an abnormality.