JPH01284016A - Contactless relay device - Google Patents

Abstract

PURPOSE:To obtain a contactless relay device without any malfunction due to electromagnetic noise, being easily destroyed and with high reliability by providing a thermo-sensing element whose resistance is changed suddenly at a prescribed temperature and a heat means heating the thermo-sensing element and activating the relay by the on/off of the thermo-sensing element. CONSTITUTION:A PTC or a CTR is used as a thermo-sensing element. The element is made of a composite sintered body of a transition metallic oxide, etc. A power supply VB, a CTRRC and a lamp L1 are connected in series and a heater RH is fitted around the CTRRC via an insulator 3. The heater RH is connected to the power supply VB via a switch SW and one unit 1 consists of the CTRRC and the heater RH. Since the temperature is a critical temperature T1 of the CTRRC or below with the switch SW turned off, the resistance of the CTRRC is very large and any current almost flows. With the switch SW turned on, the heater RH is energized and the temperature of the CTRRC rises and the resistance is decreased rapidly at the temperature of T1 or over, a drive current flows to the lamp L1 and the lamp is lighted up. The operation is reversed when a PTCRP is employed in place of the CTRRC.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a non-contact relay device that does not have mechanical contacts and controls a drive current supplied to a load.

[Prior Art] Conventionally, as a general relay device, for example, the one shown in FIG. 9(a)
, (b) is used. Figure (a)
When switch SW is off, relay coil R4 is not energized, so its contact is off, and the lamp L, which is the load, is off. When switch SW is on, relay coil R5 is energized and its contact is on. and lamp L,
is energized and lights up. Since this relay device has an electromagnetic relay that turns on and off mechanical contacts, it has a complicated structure and is expensive, and it also has problems with its lifespan because it involves switching the contacts.

Therefore, a non-contact relay device having no mechanical contacts is generally used as shown in FIG. 2(b). That is, in the same figure (b), if the switch SW is off, the transistor Qz is off, and the lamp I is turned off.

1 goes out, and when switch SW is turned on, base current flows through transistor Q, turning it on and lighting lamp L1. However, the transistor shown in FIG. 2B has problems such as malfunction due to noise, and if the capacitance is not large, the transistor easily breaks down and lacks reliability.

In addition, in the above-mentioned relay device, to prevent damage to the device itself or the load even if excessive current flows through the relay, protective measures such as a fuse or CB (contact breaker) are usually installed between the power supply and the device. It is inserted. If an excessive current flows during an overload, the fuse will be blown and the circuit will be cut off.Also, if a CB made of two boards with different expansion coefficients is used, the temperature rise due to the excessive current will cause the The two circuits were cut off by bending two plates.

Therefore, the main object of the present invention is to provide a highly reliable non-contact relay device that does not malfunction due to electromagnetic noise and is not easily destroyed.

Another object of the present invention is to provide a non-contact relay device that can protect itself from destruction due to overcurrent without providing additional protection means.

[Means for Solving the Problems] In order to solve the above-mentioned main problems, a non-contact relay device according to the present invention includes a temperature sensing element whose resistance value suddenly changes at a predetermined temperature, and a heating element that heats the temperature sensing element. and a means for performing a relay operation by turning on and off the temperature sensing element.

If the temperature sensing element is a PTC whose resistance value increases rapidly above a predetermined temperature, it is turned off when the heating means is turned on, turned on when the heating means is turned off, and when the temperature sensing element is at a predetermined temperature or lower, it is turned off. In the case of a CTR whose resistance value increases rapidly, it is turned on when the heating means is turned on, and turned off when the heating means is turned off.

In addition, in order to solve the other problems mentioned above, a non-contact relay device made according to the present invention includes a PTC whose resistance value increases rapidly when the temperature exceeds a first predetermined temperature, and a PTC connected in series with the PTC, a CTR whose resistance value increases rapidly when the temperature falls below a second predetermined temperature lower than the first predetermined temperature;
a heating means for heating the TC and the CTR, and when the heating means is turned on, the PTC and the CTR are heated to the first and second points.
The device is heated to a temperature between a predetermined temperature range and a current is passed through it.

[Function] In order to solve the above-mentioned main problem, the non-contact relay device made according to the present invention uses a temperature sensing element. As this temperature sensing element, PTC (Positive Te
mperature coefficient The
rmistor) or CTR (Critical T
There is something called "emperature Re5istor". These elements are made of composite sintered bodies of transition metal oxides such as Mn, Co, Ni, and Fe, and are shown in Figure 2 (a).
), as shown in (b), in the case of PTC, the temperature T2
It has a characteristic that the resistance value is small above T2, and increases rapidly when it becomes T2 or above (FIG. 2(a)). In the case of CTR, the temperature T.

It has a characteristic that the resistance value is large below T1 and rapidly decreases when it becomes T1 or more (FIG. 2(b)).

Therefore, when the heating means is turned on or off, the resistance of the temperature sensing element increases dramatically, prohibiting current from flowing, and when the heating means is turned off or on, the resistance suddenly decreases, allowing current to flow. Therefore, a relay operation can be performed, and the temperature sensing element does not malfunction due to noise, and since it is generally made of a sintered body, the structure is simple, highly reliable, and inexpensive.

In addition, in a non-contact relay device developed to solve another problem, when the heating means is off and the PTC or CTR is not heated, the temperature is below the second predetermined temperature of the CTR, and the resistance value is large. Therefore, almost no current flows through the PTC and CTR.

On the other hand, when the heating means is turned on, the temperature rises and the second
is higher than the predetermined temperature of PTC and lower than the first predetermined temperature of PTC. Therefore, its series resistance value decreases and current flows.

Further, when an excessive current flows, the temperature becomes higher than the first predetermined temperature of the PTC, the resistance value increases rapidly, and the current stops flowing. Furthermore, when this excessive current stops flowing and the temperature decreases, the temperature of the CTR rapidly decreases due to the heat dissipation means, and the PT
Before the temperature on the C side drops to the first predetermined temperature,
Since the temperature of the TR becomes equal to or lower than the second predetermined temperature and the resistance value of the CTR increases, the series resistance of the CTR and the PTC maintains an increased state.

As a result, the temperature rises due to the excessive current, and the resistance value of the PTC increases, and even after the excessive current is cut off, the temperature of the CTR rapidly decreases due to the heat dissipation means, and the resistance value of the CRT increases, so that the cut-off state can be prevented. and protect the CTR and PTC from destruction.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1(a) and 1(b) show an embodiment of a non-contact relay device according to the present invention. In the same figure (a), the power supply VB
.

CTRRC and lamp L1 are connected in series, and C
Heater R is installed around TRRc via insulator 3. The heater R is a heating coil wrapped around an insulator 3 as shown in the figure, and is connected to a power source VB via a switch SW, and the CTRRC and heater R constitute one unit 1. In other words, the equivalent circuit in figure (a) is Φ)
become that way.

In this configuration, when the switch SW is off, the temperature is below the critical temperature T1 of CTRRc, so CTRR
Since the resistance value of c is very large and almost no current flows, the lamp L1 is turned off.

On the other hand, when the switch SW is turned on, the heater RH is energized and the temperature of cTRRc rises, and when the temperature exceeds T1, its resistance value rapidly decreases. This causes the lamp to turn on, and a drive current flows through it, turning it on.

Also, in the circuit of the same figure, PTCR is used instead of CT RRc.
, in contrast to the above operation, when the switch SW is off, the critical temperature T2 or higher is reached and the lamp L is lit, and when the switch SW is turned on, the temperature is T2 or higher and the lamp L is turned off.

In the non-contact relay device using the CTR or PTC described above, a fuse, CB, etc. are required to prevent the temperature sensing element itself from being destroyed due to excessive current flowing through the CTR or PTC. For example, FIG. 1(a).

In the case of the non-contact relay device (b), a fuse FL is inserted between the power supply ■8 and c'rRRc or PTCR as shown in Figure 3, and if an excessive current flows during an overload, the fuse FL will be fused. If a CB made of two plates with different expansion coefficients is used, the temperature rises due to excessive current, and the two plates are bent to interrupt the circuit. .

FIG. 4 shows an embodiment of a non-contact relay device according to the present invention that does not require the above-mentioned fuse or CB. In the figure, CTRRc and PTCRP are connected in series, and CT
On the Rc side, a heat sink 2 made of a metal (for example, Aff) having a much smaller heat capacity than the CTR is attached around it. Further, a heater R11 for heating the C T RRc and the PTCR is provided in the vicinity of both to form one unit 1 .

FIG. 5 shows an application example of the above-mentioned non-contact relay device. In the same figure, a voltage Rv tr, a unit 1, and a lamp L1 are connected in series, and a series circuit of a heater R1+ and a switch SW is connected between a power source 8. Also, each CTRRc and PTCRP
The characteristics of each of the are shown in Figure 6 (
As shown in a) and (b), the critical temperature T2 of PTCRP is set higher than the critical temperature T of CT RRc, and the resistance values below and above each temperature are set as < R as shown in the figure.
Let z−R+□, R2+9R2□.

In the above configuration, its operation is shown in FIG.
This will be explained with reference to a series resistance value characteristic diagram of TR and PTC and a time chart shown in FIG.

First, when the switch SW is off, the heater RH is not energized, so the temperature of both CTRRc and PTCR is T.
, the resistance value of CTRRC is R, □, PT
The resistance value of CR, is RZI, and its series resistance value is (R
+ z + Rz r ), almost no current flows, and the lamp L1 is turned off. Next, at time L1, switch SW is turned on, heater R is energized, and CTRR is
When c and PTCR are heated, the temperature of each temperature sensing element becomes T,
above and below T2, and the resistance value of CTRRC is R
o. Since the resistance value of PTCRP becomes R21, the series resistance value decreases to (R+++Rz+), and a driving current flows through the lamp L1, turning it on.

Further, at time t2, when an excessive current flows due to an overload and the temperature rises, the temperature becomes equal to or higher than T2.

Therefore, the resistance value of PTCR becomes R2□, and the series resistance value increases to (Rz+Rz□), so that almost no current flows and the excessive current is cut off. Although the temperature decreases due to this interruption, the resistance value of RP maintains R2□ until the temperature of P T CRp falls to the critical temperature T2, and the series resistance value is (
Rz+Rz□), and the resistance value when the excessive current flows is maintained, so the cut-off state continues.

The temperature further decreases, and the temperature of CTRR reaches the critical temperature T1 at time L3, but at this time, the temperature of CTRRC decreases rapidly compared to the temperature of PTCR, due to the radiator 2 attached to CTRR. Therefore, the temperature of PTCRP is not lower than its critical temperature T2, and the series resistance is (R1□
+R2□), and continues to be in a cut-off state. When the temperature of PTCR, reaches T2 at time t4, its resistance value becomes RZ, but CTRR, has already reached RI.
Since it is □, the series resistance becomes (R+z+Rz+), and the cut-off state continues.

That is, from the above operation, when an excessive current flows, CTRR,
and PTCRP (the resistance value of one of them is the larger value (R5z, Rz□), so the excessive current is cut off and the unit 1 itself is protected from destruction.

In the above embodiment, a heat sink is attached to CTRRc, and a heat insulating material is attached around PTCRP to make it difficult for the temperature of PTCRP to be radiated. By preventing the temperature from easily falling below the critical temperature T2, the time from time t3 to t4 in FIG. 8 can be lengthened, and the interrupting characteristics against excessive current can be further improved.

In addition, heater R1 and switch SW are connected to the non-contact relay device.
The temperature sensor can be used as a temperature sensor, and the temperature of the CTR and PTC is heated by the external temperature to be detected, and when the temperature exceeds a predetermined temperature, the temperature sensing element is energized, and if an excessive current flows due to a short circuit, etc. Excessive current flowing through the thermal element is blocked and the equipment is protected.

〔effect〕

As described above, according to the present invention, CTR and PT
Since the energization and interruption of the current flowing through C can be controlled, a non-contact relay device can be constructed by combining it with a heating means, and due to the nature of these elements, a highly reliable device can be obtained without malfunctioning due to noise. . Moreover, P.T.
When C and CTR are used in combination, the device itself has a protection function, so there is no need to provide a separate protection device, and the circuit configuration is simplified, resulting in cost reduction and weight reduction.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the non-contact relay device according to the present invention, Fig. 2 is a graph showing the characteristics of the temperature sensing element used in the device of Fig. 1, and Fig. 3 is a diagram showing the characteristics of the temperature sensing element used in the device of Fig. 4 is a circuit diagram showing an example of using a conventional protection device; FIG. 4 is a diagram showing another embodiment of the present invention; FIG. 5 is a circuit diagram showing an example of a circuit using the device of FIG. 4; FIG. is a graph showing the resistance characteristics of the element used in the device shown in Fig. 4, Figs. 7 and 8 are operational characteristic diagrams for explaining the operation shown in Fig. 5, and Fig. 9 is a graph showing the resistance characteristics of the elements used in the device shown in Fig. 4. FIG. 2...Radiator, R6...CTR, RP...PTC
lR,...heater, SW...switch. ,,,RL (a) No. 9 (b) Fig. 3 (a) (b) Fig. 2 Fig. 4 Fig. 5 (b) (a) Fig. 6

Claims (4)

[Claims] (1) A non-contact relay comprising a temperature sensing element whose resistance value changes suddenly at a predetermined temperature and a heating means for heating the temperature sensing element, and performing a relay operation by turning on and off the heating means. Device. (2) Claim (1) characterized in that the temperature sensing element is a PTC whose resistance value increases rapidly above a predetermined temperature, and is turned off when the heating means is turned on, and turned on when the heating means is turned off. ) Non-contact relay device described in ). (3) The temperature sensing element is a CTR whose resistance value increases rapidly below a predetermined temperature, and is turned on when the heating means is turned on and turned off when the heating means is turned off. ) Non-contact relay device described in ). (4) A PTC whose resistance value increases rapidly when the temperature exceeds a first predetermined temperature, and a PTC connected in series with the PTC whose resistance value rapidly increases when the temperature falls below a second predetermined temperature lower than the first predetermined temperature. increasing CTR and turning on the heating means to increase the PTC and CTR to the first
and a second predetermined temperature so that a current flows through the contactless relay device.