CN204596712U - A kind of initiatively heating type overtemperature protection system - Google Patents

Abstract

The utility model discloses an active heating type overheat protection device composed of a heating sheet 2, a pin 1 and a bimetallic sheet 7. The bimetallic sheet 7 is closely attached to the heating sheet 2, and the pin 1 and the heating resistor inside the heating sheet 2 3. The bimetal strips 7 are connected in series in sequence. When in use, they need to be connected in series with the controlled appliance so that the current passing through the heating resistor 3 is consistent with the current of the controlled appliance. When the current of the controlled appliance increases abnormally, the heating resistor 3 will automatically The heating causes the bimetal strip 7 to act quickly to cut off the circuit, so as to avoid the overheating failure of the controlled appliance. When the temperature of the controlled appliance and the heating resistor 3 drops, the bimetal strip 7 resets and connects the circuit, and the controlled appliance can resume normal operation. The utility model It fully protects the safe operation of the controlled appliance and prolongs the service life of the controlled appliance.

Description

An active heating type overheating protection device

technical field

The utility model relates to an active heating type overheat protection device, which belongs to the technical field of overheat protection devices.

Background technique

Household appliance motors and electrical equipment, such as washing machine motors, air-conditioning fan motors, transformers, ballasts, electric heating appliances, etc., all need to be installed with overheating protectors. Controller, when the electrical appliance is working normally, the bimetal is in a free state, and the contacts are in the closed/open state. When the temperature rises to the action temperature value, the bimetal element is heated to generate internal stress and quickly moves to open/close the contacts. , Cut off/on the circuit, thus play a thermal protection role, when the temperature drops to the set temperature, the contact will automatically close/open, and return to normal working condition. At present, this kind of overheating protector adopts direct contact temperature sensing method or indirect contact temperature sensing method. The direct contact temperature sensing method should make the product close to the installation surface of the controlled appliance, and the abnormal temperature rise of the controlled appliance will directly transfer heat to both sides. The metal element makes the bimetal element heated to generate internal stress and quickly moves to open/close the contact; the indirect contact temperature sensing method, the product does not need to be close to the controlled appliance, it has a heat conduction between the controlled appliance and the bimetal element Components, the abnormal temperature rise of the controlled appliance transfers heat to the bimetallic element through the heat conduction element, so that the bimetallic element is heated to generate internal stress and act quickly to open/close the contact. Using such a contact temperature sensing method, in order to quickly sense the temperature change of the controlled appliance, it is necessary to install the overheat protector close to the installation surface of the controlled appliance, or install the heat conduction element close to the installation surface of the controlled appliance, sometimes It will be difficult or even impossible to install due to space constraints, and the overheated heat inside the controlled appliance is conducted to the surface, and sometimes it needs to be conducted to the bimetallic element through the heat conduction element. It has often caused internal overheating, affecting the safety of electricity use, and has a greater impact on the life of the controlled appliance.

Utility model content

The purpose of the utility model is to provide an active heating type overheating protection device, which has the advantages of rapid overheating protection action, safe operation and convenient installation.

In order to achieve the above purpose, the technical solution adopted by the utility model is: an active heating type overheating protection device, which is composed of a heating sheet, a pin, and a bimetal sheet. There is a heating resistor in the heating sheet, and the pin and the static contact are respectively connected to the The heating resistor is electrically connected, the bimetal sheet is close to the surface of the heating sheet, and one end of the bimetal sheet is connected to the moving contact. The moving contact is opposite to the static contact and can be contacted or disconnected with the action of the bimetal sheet. It is an insulating material, and the pins, static contacts, moving contacts, and bimetals are all conductive materials, and the pins, heating resistors in the heating sheet, static contacts, moving contacts, and bimetals are connected in series.

With such a structure, it is necessary to connect the active heating type overheat protection device of the utility model in series with the controlled appliance during use. When the controlled appliance is working normally, the current value in the circuit is normal, the heating sheet does not generate heat, the moving contact contacts the static contact, the circuit is turned on, and the controlled appliance works normally; when the controlled appliance increases due to abnormal current, The current passing through the heating resistor in the heating sheet also increases, and the heating sheet generates heat, causing the bimetal sheet to generate internal stress and act quickly, disconnecting the connection between the moving contact and the static contact, cutting off the circuit, and the controlled appliance has no current passing through. Therefore, it is protected to avoid overheating faults; since the circuit is cut off, no current passes through the heating resistor, the heating resistor does not heat up, the heating piece cools down, and the bimetallic piece also resets with the temperature drop, so that the moving contact contacts the static contact. When the circuit is turned on, the current recovers, and the controlled appliance can resume normal operation.

Since the bimetal strip does not passively rely on the heat generated by the controlled appliance to generate heat, but uses the heat generated by the heating sheet connected in series with the controlled appliance to actively generate heat, taking advantage of the increase in current that occurs when the controlled appliance is working abnormally, Make the heating element and the controlled appliance heat at the same time. After the heating element heats up, the bimetallic sheet is heated to generate internal stress and quickly cuts off the circuit. The overheating protection device has already activated when the current of the appliance is abnormal but the temperature rise has not reached the abnormal temperature, which is equivalent to intelligently predicting the potential overheating and preventing it in advance, which fully protects the safe operation of the controlled appliance and prolongs the time spent on the charged appliance. The useful life of the appliance. At the same time, the heating sheet is only electrically connected to the controlled appliance, and does not need to be installed close to the surface of the controlled appliance, so it can be installed at any position, and the installation position can even be far away from the controlled appliance, so it is not limited by the space of the controlled appliance. Very convenient.

Description of drawings

Fig. 1 is a front sectional view of an active heating type overheat protection device of the present invention.

Fig. 2 is a top view of the bimetal sheet driving the contacts in Fig. 1 .

Fig. 3 is a top view of the heating sheet with pins, pressing pieces and static contacts in Fig. 1 .

Fig. 4 is a schematic diagram of the utility model installed on a PCB.

In the attached picture:

1 pin; 2 heating piece; 3 heating resistor;

4 pressure pieces; 5 static contacts; 6 moving contacts;

7 bimetallic sheet; 8 PCB board.

Detailed ways

Fig. 1 to Fig. 3 have provided the concrete embodiment of a kind of active heating type overheat protection device of the present invention, and it is made up of heating piece 2, pin 1, pressing piece 4, bimetallic piece 7, and heating piece 2 has heating Resistor 3, pin 1 and pressing piece 4 are respectively located at both ends of heating piece 2, pin 1 is electrically connected to heating resistance 3, static contact 5 is located on pressing piece 4 and is electrically connected to heating resistance 3 through pressing piece 4, A part of the bimetal 7 is close to the surface of the heating sheet 2, and the end corresponding to the position of the bimetal 7 and the static contact 5 has a moving contact 6, and the moving contact 6 is opposite to the position of the static contact 5 and can be moved with the bimetal. 7 action to contact or disconnect, thereby closing or disconnecting the circuit, wherein the heating sheet 2 is ceramic insulating material, pin 1 and pressing sheet 4 are metal conductive materials, static contact 5 and moving contact 6 are silver contacts Point, the pin 1, the heating resistor 3 in the heating sheet 2, the pressing sheet 4, the static contact 5, the moving contact 6, and the bimetal sheet 7 are connected in series.

Fig. 4 is a schematic diagram of the active heating type overheating protection device of the present invention installed on the PCB board 8. During use, the active heating type overheating protection device of the present invention is generally welded on the PCB board 8 by using the pin 1 and the pressure piece 4, And connected in series with the accused appliance. When the controlled appliance is working normally, the current value in the circuit is normal, the heating sheet 2 basically does not generate heat, and the moving contact 6 and the static contact 5 are in the contact position. At this time, the circuit is conducting, and the current passes through pins 1, The heating resistor 3, the pressing sheet 4, the static contact 5, the moving contact 6, and the bimetal sheet 7 in the heating sheet 2 reach the controlled appliance, and the controlled appliance works normally. The overheating of the controlled appliance is generally caused by excessive current. For example, when the motor is blocked, the current will increase sharply. The current of 3 also increases accordingly, causing the heating sheet 2 to generate heat. Since a part of the bimetal sheet 7 is close to the surface of the heating sheet 2, the bimetal sheet 7 is heated to generate internal stress and act quickly, disconnecting the movable contact 6 and The connection of the static contact 5 cuts off the circuit, and the controlled appliance is protected by no current passing through to avoid overheating faults; since the circuit is cut off, no current passes through the heating resistor 3 at this time, the heating resistor 3 does not generate heat, and the heating sheet 2 cools down. The bimetal strip 7 also starts to reset as the temperature decreases. When the heating sheet 2 cools down to the set temperature, the bimetal strip 7 also resets thereupon, so that the movable contact 6 contacts the static contact 5. At this time, the circuit is turned on. When the current is restored, the controlled appliance can resume normal operation.

Described heating resistance 3, can adopt common resistance wire, also can adopt semiconductor resistance, PTC or ceramic PTC, when adopting PTC or ceramic PTC, because PTC thermistor is a kind of semiconductor resistance with temperature sensitivity, more than When the temperature is low, its resistance value increases stepwise with the increase of temperature. Therefore, when the heating resistor 3 adopts PTC, it can not only make the bimetal strip 7 heat and cut off the circuit, but also greatly increase the resistance in the circuit. Value, play the role of current limiting, which has a double protection.

In this specific embodiment, the static contact 5 is located on the pressure sheet 4 and is electrically connected to the heating resistor 3 through the pressure sheet 4 . In fact, the static contact 5 can be directly electrically connected to the heating resistor 3 .

The pressing sheet 4 is not necessary, because the pressing sheet 4 only plays the role of fixing the heating sheet 2, and the heating sheet 2 can be fixed by other fixing methods.

The above is only a specific embodiment of the utility model, and is not a limitation to the scope of protection of the utility model. Those skilled in the art will not depart from the spirit and scope of the utility model defined by the claims, in terms of form and Various changes made to the utility model in detail all fall into the protection scope of the utility model.

Claims (5)

1. An active heating type overheating protection device, including a pin (1), a static contact (5), a moving contact (6), and a bimetallic sheet (7), characterized in that it also contains a heating sheet (2 ), there is a heating resistor (3) inside the heating sheet (2), the pin (1) and the static contact (5) are respectively electrically connected to the heating resistor (3), and the bimetallic sheet (7) is close to the heating sheet (2) The surface of the bimetal (7) is connected to the movable contact (6), and the movable contact (6) is opposite to the static contact (5) and can be contacted or disconnected with the action of the bimetal (7). The heating sheet (2) is an insulating material, the pin (1), the static contact (5), the moving contact (6), and the bimetal sheet (7) are all conductive materials, the pin (1), the heating sheet (2 ), the heating resistor (3), the static contact (5), the moving contact (6), and the bimetal sheet (7) in the ) are connected in series. 2. An active heating type overheating protection device according to claim 1, characterized in that it also includes a pressing piece (4), and the static contact (5) is located on the pressing piece (4) and passes through the pressing piece (4). The sheet (4) is electrically connected to the heating resistor (3), and the pressing sheet (4) is a metal conductive material. 3. An active heating type overheat protection device according to claim 1 or 2, characterized in that the heating resistor (3) is a PTC. 4. An active heating type overheat protection device according to claim 1 or 2, characterized in that: the heating resistor (3) is a ceramic PTC. 5. An active heating type overheat protection device according to claim 1 or 2, characterized in that: the static contact (5) and the movable contact (6) are both silver contacts.