JPS607413B2 - Return delay device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reset delay device, which detects the magnitude of the power supply voltage when the relay is activated, and shortens the relay reset delay time as the power supply voltage is higher. The purpose of the present invention is to provide a delay device whose purpose is to increase the delay time upon return as the value decreases.

Conventionally, in electric drive devices used in automobile wipers, headlight lifting devices, etc., when the motor drive relay is simply opened and closed using an operation switch and a limit switch for stopping the stereotactic layer, the relay is driven by the opening and closing of the relay contact. The motor stops operating, but since the rotational speed during operation varies depending on the power supply voltage, the time and distance from when the limit switch for stereotactic layer stop is activated until it completely stops varies, and the motor may not be in the exact same position. An inconvenience occurred where the machine would not stop.

FIG. 1 illustrates the relationship between the rotational speed S of the electric motor and the wiper position P in a conventional wiper drive device.

In Figure 1, point A on the position axis is the starting point, point B is the stop limit switch operating point, EL is the final stopping point when the voltage is low, EH is the final stopping point when the voltage is high, and the curve SL is the voltage. SH is the speed change curve when the voltage is low, SH is the speed change curve when the voltage is high, and PL and PH' are the braking distance when the voltage is low and when the voltage is high, respectively.

In Fig. 1, the higher the power supply voltage, the higher the motor rotation speed at limit switch operating point B, and the higher the control distance P.
H is longer than PL.

Therefore, the stop position changes due to the influence of the voltage, and the wiper has a problem in that the position of the blade changes when the wiper is stopped. For example, other than wiper
The same problem occurs in drive devices that use electric motors to stop at a fixed position, such as headlight lifting devices, and devices that use DC motors are particularly susceptible to power supply voltage fluctuations. The present invention has been made in view of the above-mentioned drawbacks of the prior art.Examples of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 shows a wiper drive circuit showing an embodiment of the present invention. SW is a running switch, LS is a stop limit switch contact, RY is a relay coil, RYa is a normally open contact of relay RY, and RYb is a relay RY. , M is the armature of the DC motor, Q is the PNP transistor "Q2,
Q is a voltage comparator circuit element, R, ~R7 are resistors "C,,C
2 is a capacitor, and D is a constant voltage diode. Next, to explain the specific circuit configuration, the emitter and collector output circuit of the transistor Q are connected in series to the parallel circuit of the operation switch SW and the stop limit switch LS, and the emitter and collector output circuit of the transistor Q are connected in series. Connected between DC power supplies P and N.

Further, a series circuit of relay contact RYa and electric motor M is also connected to a DC power supply, and relay contact RYb is connected to electric motor M in parallel. In addition, the limit switch consists of a series circuit of resistors R2 and R3, and a series circuit of resistors R2 and R3 between the connection point P between the emitter of transistor Q and the emitter of transistor Q, and the power supply N.
Seven series circuits are connected to each other. Further, a resistor R, is connected between the base of the transistor Q, and the output terminal of the first voltage comparator circuit Q2, and the inverting input terminal of the first voltage comparator circuit Q2 is connected to the connection point of the resistors R2 and R3. A resistor R4 and a series circuit of a capacitor C and a resistor R5 are connected between the non-inverting input terminal of the first voltage comparison circuit Q2 and the connection point P, and a constant voltage is connected in parallel to the capacitor C. A diode D is connected in the direction shown, the non-inverting force terminal of the first voltage comparator circuit Q2 and the output terminal of the second voltage comparator circuit Q3 are connected, and the inverting input terminal of the second voltage comparator circuit Q3 is connected. and the capacitor C2 and the resistor R
7 is connected to the subsequent point, and the capacitor C2 is connected to the resistor R6.
are connected in parallel, and the non-inverting input terminal of Q3 is connected to the power supply terminal N.
It is connected to the. In addition, in FIG. 3, power supply terminal P is positive, N is negative, and voltage comparison circuits Q2, Q
The output circuit is assumed to be an emitter-grounded open collector transistor output terminal, and the input state is such that the minus sign is an inverting input terminal and the plus sign is a non-inverting input terminal. Figure 3 shows the changes in each signal when the circuit shown in Figure 2 is operated, SW is the operation switch signal, LS is the stop limit switch contact signal, and RY (H) is the power supply voltage. When the power supply voltage is low, the operating state of the coil is RY (L), and when the power supply voltage is low, the operating state of the coil is VC2.
(H), VC2 (L) are voltage change curves of capacitor C2 when the voltage is high and low, respectively, VC is a voltage change curve of capacitor C, VR2 (H), VR2 (L)
are the voltage across resistor R2 when the voltage is high and low, respectively, and the change curves VR7 (H) and VR7 (L) are the voltage change curves across resistor R7 when the voltage is high and low, respectively, SH and SL show the motor rotation speed change curves when the voltage is high and low, respectively, A is the starting point, B is the operating point of the stop limit switch, and CH and CL are the IJ Ray OFF points when the voltage is high and low, respectively. ,
E indicates the final stopping point.

The operation will be explained with reference to FIGS. 2 and 3.

Now, when the operation switch SW is closed, the capacitor C2 is charged through the resistor R7, and current flows through the resistor R7 through the resistor R6. A positive voltage is applied to the terminal and a negative voltage is applied to the non-inverting input terminal.

As a result, the output terminal of the voltage comparator circuit Q3 is turned on, and the capacitor C is charged via the resistor R5.
The charging voltage at this time is limited by the constant voltage diode D, and is kept at a constant voltage regardless of the power supply voltage. The power supply voltage is connected to the inverting input terminal of the voltage comparison circuit Q2 through the resistor R2.
The voltage is divided by R3 and applied, and although it varies depending on the power supply voltage, at least a positive voltage is applied. Voltage comparison circuit Q2
Since the output terminal of the voltage comparator circuit Q is connected to the non-inverting input terminal of , it is brought close to the negative potential.
As a result, the output terminal of the voltage comparator circuit Q2 is turned on, and the output terminal of the voltage comparator circuit Q2 is turned on, and the output terminal of the voltage comparator circuit Q2 is turned on. A base current is applied to the transistor Q, the output terminal of the transistor Q becomes ○N, and the relay coil RY is energized. When relay coil RY is energized, contact RYb opens, RYa closes, and motor M is operated. Next, even if the operation switch SW is opened, all the circuits continue to operate as long as the stop limit switch LS is closed. When the contact of the limit switch LS opens at the limit switch operating point, the power to the entire relay circuit is cut off, but while the charge charged in the capacitor C2 is discharged, the output of the transistor Q is closed is applied to the relay coil via resistor R7. Capacitor C
When the discharge of 2 starts, the discharge current flows through the transistor Q,
Current flows through the series circuit of the output circuit, relay coil RY, and resistor R7, the direction of the current in resistor R7 is reversed, and the voltage across both terminals VR7 is reversed. As a result, the voltage to both input terminals of voltage comparator circuit Q3 is The non-inverting input terminal has a more positive potential than the inverting input terminal, and the output of the voltage comparison circuit is turned off.

When the output circuit of the voltage comparison circuit Q3 is turned off, the electric charge charged in the capacitor C is discharged via the resistor R5 and the resistor R4. If resistor R5 is set to a lower resistance value than resistor R4, the voltage of capacitor C is almost applied to resistor R4, and the discharge time constant is determined by capacitor C and resistor R4. . The discharge curve of capacitor C, is shown by VC, (dotted line), which does not change depending on the power supply voltage. On the other hand, when the capacitor C2 is discharged, the circuit of the resistors R2 and R3 is also energized, and the voltage shown by the curve VR2 is applied to the resistor R2. This curve VR2 changes depending on the power supply voltage and is indicated by VR2(H) and V2(L), respectively. A resistor R is connected between the input terminals of the voltage comparison circuit Q2.
Immediately after the capacitor C2 starts discharging, the voltage difference between the voltage applied to the capacitor C2 and the voltage applied to the resistor R4 becomes negative, and the output terminal of the voltage comparator circuit Q2 remains in the ON state, and the voltage of the resistor R , the base current flows through the transistor Q, and the relay coil RY continues to be energized.
In order to energize relay RY, capacitor C2 is discharged,
The pressure gradually decreases, but the discharge time of capacitor C,
If you set it shorter than the discharge time constant of capacitor C2,
As the discharge of the capacitor C rapidly progresses, the voltage across the resistor R4 suddenly drops, and the voltage sacrifice applied to the input terminal of the voltage comparison circuit Q2 is reversed after a certain period of time. When the voltage applied to the input terminal of Q2 is reversed and the non-inverting input terminal side becomes a higher potential than the inverting input terminal, the output terminal of Q2 becomes FF,
Transistor Q loses base current and becomes FF, cutting off current to relay coil RY. When the relay coil RY is de-energized, the contact RYa is cut off and the contact RYb is closed, causing the motor M to suddenly stop. Here, since the charging voltage to capacitor C is a constant value regardless of the power supply voltage, and the charging voltage to capacitor C2 is proportional to the power supply voltage, the voltage of resistor R2 when the L power supply voltage is high is The relationship between the voltage across both ends, the voltage across the capacitor C when it is low, and the voltage across the capacitor C changes as shown in the curves VR2(H), VR2(L), and VC in Figure 3, and when the power supply voltage is high, Signal inversion occurs early and occurs later when the power supply voltage is low. When each signal is reversed at this time, the relay is OFF.
In FIG. 3, this corresponds to the CH point and the CL point. The motor M starts to stop abruptly from the positions of the CH point and the CL point according to the power supply voltage, and completely stops at the final stopping point E. Here, it is possible to make the final stopping points coincide by appropriately setting the discharge time constant of the capacitor C and appropriately selecting the stopping delay time, which varies depending on the power supply voltage. As is clear from the above description, according to the present invention, when the power is applied, the relay operates immediately, and when the power is cut off, the relay maintains zero operation by discharging the capacitor, and the charging and tumultuous pressure proportional to the power supply voltage is maintained. By comparing the divided voltage and constant voltage value, the relay returns after a relatively short time when the power supply voltage is high, and returns after a long time when the power supply voltage is low. For example, when used in a drive device with an electric motor,
Differences in braking distance of the electric drive device due to fluctuations in power supply voltage can be corrected, which has the effect of improving stopping position accuracy.

In addition, in the description of the embodiment, the switch element connected in series with the relay is described as a transistor, but the effect is the same even if the second relay is used.

Although the voltage comparator is shown as an example of an integrated circuit, it may be a combination of other semiconductors, and although the output of the voltage comparator has been described as a grounded-emitter, open-collector transistor, it may be a combination of other elements. Furthermore, the connection polarity within the circuit does not necessarily have to match that shown in FIG. 2, and may be connected to other polarities that provide the same operation.

[Brief explanation of the drawing]

FIG. 1 is a speed change curve diagram of an electric motor in a conventional wiper drive device, FIG. 2 is an electric circuit diagram of a wiper drive circuit according to an embodiment of the present invention, and FIG. 3 is a diagram of each signal change curve in an embodiment of the present invention. It is a diagram. Mountain...Limit switch for fixed position stop, SW...
・Motor operation switch, RY...Relay coil, RYa...Relay normally open contact, RYb...
... Normally closed contact of relay, M ... Motor, Q
．． ...Transistor, Q2, Q3...
Voltage comparison circuit, C,, C2... Capacitor, D...
... Constant voltage diode, R, ~R7...Resistor, S
H, SL... Motor rotation speed change curve. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A series circuit of a second capacitor and a seventh resistor is connected in parallel to the series circuit of the output terminal of the switch element and the relay coil, and a sixth resistor is connected in parallel to the second capacitor, A series circuit of a first capacitor, a fifth resistor, and an output switch terminal of a second voltage comparator is connected in parallel to the series circuit of the output terminal of the switch element and the relay coil. A constant voltage diode is connected in parallel to the capacitor with a polarity that limits the charging voltage of the capacitor, and an inverting input terminal and a non-inverting input terminal of the second voltage comparator are connected to both ends of the seventh resistor. When charging the second capacitor, the output switch terminal is connected to the closed polarity, a fourth resistor is connected in parallel to the series circuit of the first capacitor and the fifth resistor, and the output terminal of the switch element is connected to the polarity that closes the output switch terminal. A series circuit of a second resistor and a third resistor is connected in parallel to the series circuit of the switch element and the relay coil, and a series circuit is formed between the input terminal of the switch element, the output terminal of the switch element, and the relay coil. is connected to one side terminal of the first voltage comparator via a first resistor and an output switch terminal of the first voltage comparator to a polarity in which a switch element closes when the output switch of the first voltage comparator is closed; The inverting input terminal and the non-inverting input terminal of the first voltage comparator are connected to the connection point between the second resistor and the third resistor, and the output switch terminal of the second voltage comparator and the fifth resistor are connected to each other. A return time delay device characterized in that the output switch terminal of the first voltage comparator is connected to the connection point with the voltage comparator so that the output switch terminal of the first voltage comparator is closed when the output switch terminal of the second voltage comparator is closed.