JPH06333480A - Relay driving device - Google Patents

Abstract

PURPOSE:To lengthen the life of a relay by driving the relay through a D type FF with an oscillation output which is outputted from an oscillation circuit and asynchronous with a commercial power source. CONSTITUTION:An electric power from a commercial power supply 1 is supplied to a load 9 through a switch 8 and also supplied to a D.C. power supply circuit 2. By D.C. power from the circuit 2, an oscillation output which is asynchronous with the synchronization of the power supply 1 is generated, and applied to a clock terminal DK of a D type FF 11 as the clock. The temperature of the load 9 measured with a temperature sensor 4 and the temperature set with a temperature setting device 3 are compared with a comparison circuit, and the compared result is applied to a data terminal of the FF 11, and by a Q output of the FF 11, ON-OFF of a transistor is controlled, and an contact electrode of the relay 7 randomly repeats a positive electrode and a negative electrode independent of the synchronization of the commercial power supply. The contact of the relay does not generate projections and recesses, and the life of the relay is lengthened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay drive device for energizing and interrupting a load connected to a commercial power source.

[0002]

2. Description of the Related Art Conventionally, a relay has been used to energize and interrupt a load connected to a commercial power source. The conventional relay drive device will be described below.

FIG. 4 is a block diagram of a conventional relay driving device, FIG. 5 is a timing diagram of relay opening / closing of a conventional relay driving device, and FIG. 6 is a relationship between a commercial power source cycle of the conventional relay driving device and a relay opening / closing timing. It is a figure. In FIG. 4, 1 is a commercial power supply, 2 is a DC power supply circuit for making a circuit DC power supply from the commercial power supply 1, 3 is a temperature setter for setting a temperature, 4
Is a temperature sensor, 5 is a comparison circuit which compares the set value of the temperature setter 3 with the signal of the temperature sensor 4 and generates a drive signal for opening and closing the relay 7, and 6 is a relay signal by the drive signal from the comparison circuit 5. 8 is a transistor for driving
, 9 is a load such as a heat source.

In the above circuit configuration, as shown in FIG. 5, when the temperature of the load 9 is low and the signal of the temperature setter 3 is smaller than the signal of the temperature sensor 4, the output signal of H level of the comparison circuit 5 is output. As a result, the transistor 6 is turned on and the relay 7 is also turned on, so that the contact 8 of the relay 7 is closed. Therefore, the commercial power supply 1 is energized to the load 9, and if the load 9 is a heat source, the temperature rises. Next, when the temperature rises and the signal of the temperature setter 3 is larger than the signal of the temperature sensor 4, the comparison circuit 5 generates an L level output signal, the transistor 6 is turned off, and the relay 7 is also turned off. The contact 8 of 7 is open. Therefore, if the commercial power supply 2 is not energized to the load 9 and the load 9 is a heat source, the temperature drops. By the above operation, temperature control is performed so that the signal of the temperature sensor 4 has the same value as the signal of the temperature setter 3.

However, since the temperature sensor 4 and the temperature setting device 3 are connected to the DC power supply circuit 2, the signals of the temperature sensor 4 and the temperature setting device 3 are very small as shown in FIG. Includes ripple synchronized with the cycle,
Moreover, since the temperature sensor 4 generally converts a slight change in resistance value due to temperature to a voltage value as compared with the temperature setter 3, ripples are large, and the signal of the temperature sensor 4 is lowered, so that the temperature setter 3 is changed.
2 and the timing of the signal of the temperature sensor 4 increasing and intersecting with the signal of the temperature setting device 3 are always the timings synchronized with the cycle of the commercial power supply 1. Therefore, the output signal from the comparison circuit 5 is synchronized with the cycle of the commercial power supply 1, and the contact 8 of the relay 7 is also opened and closed at the timing synchronized with the cycle of the commercial power supply 1.

Next, the contact 8 of the relay 7 will be described.
FIG. 7 is a side view of a contact 8 of a general relay 7 used in a conventional relay drive device. The contact 8 of the relay 7 configured as described above generates an arc due to the action of the current continuously flowing at the time of opening / closing, and the metal material of each of the contacts 15 and 16 is ionized due to the high heat generated by the arc, and the contact is made. When 15 is a positive electrode with respect to the contact 16, the metal ion (M−) of the contact 16 is attracted to and adheres to the contact 15, which is a positive electrode, and has a convex shape. On the contrary, the contact surface of the contact 16 is concave accordingly. Becomes When the contact 8 is repeatedly opened and closed at the timing when the contact 15 is always positive with respect to the contact 16, the contact surface of the contact 16 becomes concave, and the contact surface of the contact 15 becomes convex, and the contact 8 of the relay 7 is closed. When the contact points 15 and 16 are meshed with each other, the contact points 15 and 16 do not remain engaged even if the relay 7 itself is opened, and the closed state continues and malfunction occurs. Further, even when the contact 8 is opened and closed at a timing when the contact 15 is always negative with respect to the contact 16, the contact 16 becomes convex and the contact 15 becomes concave, and similarly, the respective contacts 15 and 16 mesh with each other to cause defective operation.

However, when the electrodes of the contact points 15 and 16 repeat positive and negative electrodes randomly, the contact points 15 and 16 are contacted.
Since the metal ions of (6) repeatedly move between the contacts 15 and 16, no unevenness is generated on the contacts 15 and 16 and they do not engage with each other, so that the life of the contact 8 is extended and reliability is improved.

[0008]

However, since the contacts 8 of the relay 7 are opened and closed in synchronization with the cycle of the commercial power source 1 in the above-described conventional configuration, the contacts 1 of the relays 7 are not connected.
When the contacts 5 and 16 are opened and closed, the contacts 15 and 16 are fixed to either the positive electrode or the negative electrode.
When the concavities and convexities 5 and 16 are meshed with each other, the life of the contact 8 is shortened, and the contact 9 remains closed and does not open, the load 9 is continuously energized and the load 9 is a heat source. There was a problem in that it would lead to rising and cause a fire.

[0009]

In order to solve the above problems, the present invention comprises signal delay means for delaying a drive signal for driving a relay by a signal from an oscillating means that oscillates asynchronously with a cycle of a commercial power source. .

[0010]

According to the present invention, the drive signal of the relay can be made asynchronous with the cycle of the commercial power source, and the opening / closing timing of the relay can be made asynchronous with the cycle of the commercial power source.

[0011]

1 is a block diagram of a relay drive device according to an embodiment of the present invention. In FIG. 1, 1 is a commercial power supply, 2 is a DC power supply circuit for producing a circuit DC power supply from the commercial power supply 1, 3 is a temperature setter for setting temperature, 4 is a temperature sensor, 5 is a set value of the temperature setter 3. A comparison circuit that compares the signal of the temperature sensor 4 and generates a drive signal for opening and closing the relay 7, 6 is a transistor that drives the relay 7 by the drive signal from the comparison circuit 5, 8 is a contact of the relay 7, and 9 is A load such as a heat source, 10 is an oscillation circuit that oscillates asynchronously with the cycle of the commercial power supply 1, 11 is a delay D flip-flop IC
Is.

The operation of the relay drive device configured as described above will be described below. Here, the oscillation circuit 10
The operation other than the operation of the D flip-flop IC11 and the operation of the conventional flip-flop IC11 is the same as the operation described in the related art, and thus the description thereof is omitted. First, the output signal of the comparison circuit 5 is input to the data input terminal D of the D flip-flop IC11, and the output signal of the oscillation circuit 10 is input to the clock terminal CK of the D flip-flop IC11.
The output terminal Q of the D flip-flop IC11 is output to the transistor 6 as a relay drive signal. The D flip-flop IC11 has a data input terminal D as shown in FIG.
2 has a function of outputting from the output terminal Q at the rising timing of the signal input to the clock terminal CK, so that the comparator circuit 5 synchronizes with the cycle of the commercial power source 1 as shown in FIG. D flip-flop IC11
, The data output terminal Q of the D flip-flop IC11 does not change.

Next, when a signal from the oscillation circuit 10 is input to the clock terminal CK of the D flip-flop IC11, the signal from the comparison circuit 5 is output from the output terminal Q of the D flip-flop IC11 at the rising timing of this signal. It is output and becomes a drive signal for the relay 7.

However, since the signal from the oscillation circuit 10 is asynchronous with the cycle of the commercial power source 1, the output signal from the output terminal Q of the D flip-flop IC 11, that is, the drive signal of the relay 7 is the cycle of the commercial power source 1. Will be asynchronous to. For this reason, the operation of the relay 7 becomes asynchronous with the cycle of the commercial power supply 1, and each of the contacts 8 of the relay 7 repeats the positive and negative polarities, so that the metal ions of the contacts 8 repeatedly move between the respective contacts 8, resulting in unevenness. It does not occur and the life of the contact 8 is improved.

[0015]

As described above, the relay drive device of the present invention includes the signal delay means for delaying the drive signal for driving the relay by the signal from the oscillation means which oscillates asynchronously with the cycle of the commercial power source. The drive signal can be made asynchronous with the cycle of the commercial power source, and the opening / closing timing of the relay can be made asynchronous with the cycle of the commercial power source, so that the contact life of the relay can be improved and the reliability of the product can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a relay drive device according to an embodiment of the present invention.

FIG. 2 is a timing diagram of a D flip-flop IC used in a relay drive device according to an embodiment of the present invention.

FIG. 3 is a timing chart of opening / closing of a relay of a relay drive device according to an embodiment of the present invention.

FIG. 4 is a block diagram of a conventional relay drive device.

FIG. 5 is a timing chart of opening / closing of a relay of a conventional relay drive device.

FIG. 6 is a relationship diagram between a commercial power supply cycle of a conventional relay drive device and a relay opening / closing timing.

FIG. 7 is a side view of contacts of a general relay used in a conventional relay drive device.

[Explanation of symbols]

 1 Commercial Power Supply 2 DC Power Supply Circuit 3 Temperature Setting Device 4 Temperature Sensor 5 Comparison Circuit 6 Transistor 7 Relay 8 Contact 9 Load 10 Oscillation Circuit 11 D Flip-Flop IC

Claims (1)

[Claims] 1. A relay drive device for energizing and interrupting a load connected to a commercial power source, the drive signal output means outputting a signal for driving the relay, and oscillating asynchronously with a cycle of the commercial power source. A relay drive device comprising: an oscillating means; and a signal delay means for delaying a signal output from the drive signal output means by a signal from the oscillating means.