WO2019014946A1

WO2019014946A1 - Electrothermal door lock protection circuit, control board, door lock, door lock protection accessory, and washing machine

Info

Publication number: WO2019014946A1
Application number: PCT/CN2017/093948
Authority: WO
Inventors: 王文; 王上源
Original assignee: 深圳拓邦股份有限公司
Priority date: 2017-07-21
Filing date: 2017-07-21
Publication date: 2019-01-24

Abstract

Provided are an electrothermal door lock protection circuit, a control board, a door lock, a door lock protection accessory, and a washing machine. The door lock protection circuit comprises: a switch device, an over-current protection PTC and a load connection end which are connected in series, wherein the over-current protection PTC is a 2-pin PTC that can be onboard. By connecting the 2-pin over-current protection PTC in series between a switch device and a load connection end, when a circuit is subjected to high voltage breakdown, transient breakdown caused by internal reasons of itself and the other unknown types of breakdown, leading to a sharp increase in the current in the circuit, the resistance of the over-current protection PTC will sharply increase due to temperature increase, such that the current in the circuit is rapidly attenuated to a very small stable value, thereby avoiding damage to components in the circuit, and providing a great guarantee of the safety of the circuit.

Description

Electric door lock protection circuit, control board, door lock, door lock protection accessory and washing machine

Technical field

[0001] The utility model belongs to the field of washing machines, and particularly relates to an electric heating type door lock protection circuit, a control board, a door lock, a door lock protection accessory and a washing machine.

Background technique

[0002] The electric door lock is an essential safety protection device for the washing machine. Its mechanical protection device can prevent the user from hitting the side door during the washing process, causing the water in the washing chamber to rush out, and also preventing accidental mechanical damage. In short, work The middle door is unbeatable. Its working principle is a PTC heating element in the door lock. After the power is applied, the bimetal structure is inflated, the mechanical structure is turned on, and the latch is locked at the same time.

, to prevent accidental snoring. By controlling the PTC's power on and off, the door lock can be locked and unlocked.

[0003] In the prior art, as shown in FIGS. 1 and 2, the door lock control circuit typically uses: a relay or a thyristor to connect the main PTC (ie, the PTC heating element) to the circuit. However, in actual use, the door lock circuit may be broken down (the breakdown causes the instantaneous breakdown caused by the internal cause of the door lock itself and other unexplained breakdown), resulting in the thyristor/relay being Burnt, and even other components are burned out. Especially in India, this phenomenon is particularly noticeable due to the unstable grid voltage and the humid and rainy weather in the area, which not only increases the after-sales cost, but also greatly reduces the manufacturer's goodwill.

[0004] After field investigations and repeated experimental observations, the reason for this phenomenon is found to be: The working environment of the washing machine is relatively humid, and the door is latched in the mechanical action device, which cannot be sealed against moisture and water, and the door lock works. It is the PTC heating bimetal that drives the mechanical movement. When the PTC is hot and cold alternately, the condensation of moisture in the air will cause metal corrosion inside the door lock, and the rusted metal fragments will cause random short circuit; The washing machine, the plastic around the PTC will be carbonized due to the heating between the long turns, the humid environment is paralyzed, the short circuit breakdown short circuit is easily caused by the voltage of the grid, the relay or the thyristor is burnt, and even the circuit board is directly burned.

[0005] In the prior art, in order to prevent the line from being burned out, some washing machine electronic control board manufacturers increase the overcurrent capability of the line by widening the PCB printing line and stacking tin on the printed line to prevent the line from being damaged. Production match The parts are burned out, but other accessories may only meet the production standards, and do not have the characteristics of high temperature and high current resistance. Therefore, the above short circuit phenomenon occurs. These parts that cannot withstand high temperature and high current may be burned out, and the above cannot be fundamentally solved. problem. Therefore, it is necessary to find a simple, convenient, low-cost method to solve the problem of instantaneous short-circuit of the heated door lock, to ensure the performance of the washing machine, to avoid potential safety hazards to the user, and to avoid the increase in the after-sale cost of the manufacturer.

technical problem

The utility model provides an electric heating type door lock protection circuit, which aims to solve the problem that the door lock circuit is easily damaged by a large current impact.

Problem solution

Technical solution

[0007] The present invention is implemented in this way, an electric heating type door lock protection circuit, the protection circuit includes: [0008] a series connection of the switching device, an overcurrent protection PTC and a load connection end;

[0009] The overcurrent protection PTC is a 2-pin, onboard PTC.

[0010] Preferably, the overcurrent protection PTC is a ceramic PTC.

[0011] The utility model also provides a washing machine control board, wherein the control board has an electric heating type door lock protection circuit;

[0012] The protection circuit is as described in any one of the above.

[0013] The present invention also provides a washing machine, the washing machine comprising:

[0014] a washing machine body;

[0015] A control panel disposed in the body of the washing machine, the control panel being as described above.

[0016] The present invention also provides a washing machine electric door lock, the door lock includes:

[0017] an overcurrent protection PTC, the overcurrent protection PTC is a 2-pin onboard PTC;

[0018] The overcurrent protection PTC-terminal is connected to the main PTC, and the other end is connected to the door lock terminal.

[0019] Preferably, the overcurrent protection PTC is a ceramic PTC.

[0020] The present invention also provides a washing machine, the washing machine comprising:

[0021] a washing machine body;

[0022] A door lock mounted on the body of the washing machine, the door lock being as described in any one of the above.

[0023] The utility model also provides a door lock protection accessory, wherein the door lock protection accessory comprises: [0024] The overcurrent protection PTC is a 2-pin PTC, and the two pins of the overcurrent protection PTC are respectively connected to two terminals of the door lock protection accessory.

[0025] Preferably, the overcurrent protection PTC is a ceramic PTC.

Advantageous effects of the invention

Beneficial effect

[0026] In the electrothermal door lock protection circuit provided by the present invention, a 2-pin overcurrent protection PTC is connected in series between the switching device and the load connection end, and the circuit is subjected to a large voltage shock, thereby causing a current in the circuit. A sharp increase in 吋, overcurrent protection PTC's resistance will increase sharply due to temperature rise, the current in the circuit will quickly decay to a small stable value, to avoid damage to the components in the circuit, the safety of the circuit Provides great assurance.

Brief description of the drawing

DRAWINGS

1 is a schematic diagram of a door lock circuit provided by the prior art;

2 is a schematic diagram of another door lock circuit provided by the prior art;

3 is a circuit diagram of an electrothermal door lock protection circuit provided by an embodiment of the present invention;

4 is a circuit diagram of an electrothermal door lock protection circuit according to another embodiment of the present invention;

5 is a front view of an overcurrent protection PTC provided by the present invention;

6 is a graph showing resistance temperature characteristics of an overcurrent protection PTC according to an embodiment of the present invention.

Embodiments of the invention

[0033] In order to make the objects, technical solutions, and advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0034] In the electrothermal door lock protection circuit provided by the utility model, a two-pin overcurrent protection PTC (ie, a positive temperature coefficient thermistor) is connected in series between the switching device and the load connection end, when the current in the circuit When the 吋 is increased, the resistance of the overcurrent protection PTC will increase sharply, so that the current in the circuit is quickly attenuated to a small stable value, which ensures the safety of the circuit. [0035] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0036] In the embodiment provided by the present invention, the electrothermal door lock protection circuit includes:

[0037] A series-connected shut-off device, an overcurrent protection PTC, and a load connection; an overcurrent protection PTC is a 2-pin, on-board PTC to solder the overcurrent protection PTC to the circuit. In this embodiment, the positive temperature coefficient characteristic of the overcurrent protection PTC ensures the safety of the circuit, and the circuit is subjected to high voltage breakdown, instantaneous breakdown caused by internal internal causes or other unexplained breakdown, in the circuit. The current suddenly increases, the temperature of the overcurrent protection PTC rises very high, and the resistance of the overcurrent protection PTC also increases sharply.

[0038] In this embodiment, the overcurrent protection PTC is an onboard PTC, as shown in FIG. 5, the maximum width D is 18.5 mm, the maximum height H is 25 mm, and the lead diameter d is 0.7±0.05. Mm, the distance F between the two pins' center axis is 5.0 soil 1.Omm, and the maximum thickness h of the overcurrent protection PTC is 5 mm.

[0039] As shown in FIG. 6, after the circuit works normally, the resistance of the overcurrent protection PTC is small. If the circuit is subjected to a large voltage, the current flowing through the overcurrent protection PTC suddenly increases, and the overcurrent protection is performed. The temperature of the PTC rises rapidly, which in turn increases the resistance of the overcurrent protection PTC. That is, when the temperature of the overcurrent protection PTC rises rapidly from Tc to Tp吋, the resistance rapidly increases from Rc to Rp. The current in the circuit is quickly attenuated to a small stable value, which avoids damage to the components in the circuit and provides great guarantee for the safety of the circuit.

[0040] As shown in FIG. 3, in the present embodiment, a relay having a small influence of a surge current and a good on-off characteristic is used as a switching device, and one end of the PTC is protected by an overcurrent (one of the pins). Connected to one end of a set of common contacts of the relay, the other end of the overcurrent protection PTC (the other pin) is connected to the load (ie the main PTC in the figure), that is, the pin is connected to the load, the load The other end and the other end of the set of common contacts are respectively connected to the live and neutral lines of the mains, and the relay coil is electrically connected to the PTC access circuit. It can be understood that the positional relationship between the components can be changed as long as the load overcurrent protection PTC and the switching device are connected in series.

[0041] As shown in FIG. 4, in another embodiment provided by the present invention, a thyristor having a small volume, a fast switching speed, and a low price is used as a switching device, such as a bidirectional thyristor, etc. Circuit Connections The present invention is not described here.

[0042] In addition, in the actual test process, when the overcurrent protection PTC is a PTC吋 made of an organic polymer material, although it can also function as a protection circuit for a large current impact, the service life is not long, after passing through After 40 to 60 impact tests, the overcurrent protection PTC is damaged and does not work properly. So in order to improve In the present embodiment, the overcurrent protection PTC uses a ceramic PTC, which is based on barium titanate, and is miscellaneous with other such as 8, Si, Li, P, Cs, Nd, Al, Ti, etc. Specifically, the ceramic P TC is mainly composed of materials such as BaTi03, B203, SiO2, Li20, P205, Cs20, Nd203, A1203, Ti02, etc. In this embodiment, the resistance of the over-current protection PTC is small, Only a dozen or so ohms, working 吋, can withstand voltage surges exceeding 500V, and high current surges exceeding 40A, when the temperature is above the Curie temperature 居 (Curie temperature is 143 ° C ~ 157 ° C), resistance step Increased by more than 10,000 times, it is especially suitable for protecting the heating type door lock circuit to prevent damage to the door lock circuit caused by large current surge caused by short circuit and the like.

[0043] In the inspection process of the protection circuit using the above ceramic PTC provided by the present invention, after more than 10,000 times of instantaneous short circuit and large current impact test, the load and other components in the circuit can work normally. Therefore, the protection circuit provided by the utility model can well protect components such as loads in the circuit. In addition, during the test, the circuit is subjected to short-circuit impact test at room temperature using the mains (power supply voltage 220V). After 30 seconds of power-off, the power is turned off. The over-current protection PTC can return to the initial value within 60 seconds. The circuit can be put into use again. Therefore, when the protection type circuit provided by the embodiment is used in the door lock of the heating type washing machine, not only the safety of each device in the door lock can be protected in the short circuit, but also can be quickly put into use after the power failure maintenance.

[0044] The present invention also provides a washing machine control panel having an electric heating type door lock protection circuit; the protection circuit is as described above. In this embodiment, the control board includes a PCB board or the like. The PCB board is provided with a protection circuit as described in the above embodiment, and the main PTC of the electrothermal door lock is serially connected to the protection circuit through the wire, when the circuit suddenly increases. The temperature of the overcurrent protection PTC increases, and the resistance of the overcurrent protection PTC increases by more than 10,000 times, so that the current in the circuit is quickly attenuated to a small stable value, thereby effectively preventing the electrothermal door lock. The components and the control board inside are burned out.

[0045] The present invention also provides a washing machine, the washing machine comprising:

[0046] a washing machine body; and a control panel disposed in the washing machine body, the control panel being as described in the above embodiment.

In the embodiment, the washing machine uses the above-mentioned control board, which effectively avoids the phenomenon that the control board is easily burned in the event of a large current impact, which makes the whole washing machine more safe and reliable, and greatly reduces the after-sales maintenance frequency of the whole machine factory. Degree and maintenance costs have improved the goodwill of the whole plant.

[0047] The utility model also provides an electric heating door lock of a washing machine, the door lock comprising: [0048] Overcurrent protection PTC; overcurrent protection PTC-side is connected to the main PTC (PTC ceramic electric heating element), and the other end is connected to the door lock terminal; the overcurrent protection PTC is a 2-pin on-board PTC, so that The flow protection PTC is soldered to the board. One end of the overcurrent protection PTC (one of the pins) is connected to the main _PTC , and the other end of the overcurrent protection PTC (the other pin) is connected to the door lock terminal, that is, the overcurrent protection PTC is connected in series with the main PTC. The door lock terminal can be directly connected to the neutral line of the mains, and the other end of the main PTC can be directly connected to the live line of the mains. Since the door lock of the washing machine is a heated door lock, the main PTC for heating during use is in a working state, and the use of the long raft will cause the plastic around the main PTC to be carbonized, and the wet working environment of the washing machine is highly likely to cause Short circuit, in this embodiment, the door lock uses a protection circuit including an overcurrent protection PTC. When a short circuit occurs, the temperature of the overcurrent protection PTC rises rapidly, and the resistance value thereof also increases stepwise. The current in the circuit effectively protects the safety of the door lock.

[0049] As shown in FIG. 6, after the circuit works normally, the resistance of the overcurrent protection PTC is small, and if the circuit is subjected to a large voltage, the current flowing through the overcurrent protection PTC suddenly increases, and the overcurrent protection is performed. The temperature of the PTC rises rapidly, which in turn increases the resistance of the overcurrent protection PTC. That is, when the temperature of the overcurrent protection PTC rises rapidly from Tc to Tp吋, the resistance rapidly increases from Rc to Rp. The current in the circuit is quickly attenuated to a small stable value, avoiding damage to components in the circuit, making the entire door lock more secure and reliable.

In addition, in the embodiment, the overcurrent protection PTC adopts a ceramic PTC to improve the protection effect of the overcurrent PTC and further improve the safety performance of the door lock. Further, in the present embodiment, the size and material composition of the overcurrent protection PTC are as described in the above embodiments.

[0051] The present invention also provides a washing machine, the washing machine comprising:

[0052] a washing machine body; and a door lock mounted on the body of the washing machine, the door lock being as described in the above embodiment. The embodiment provides a washing machine, which uses the door lock described in the above embodiment, so that the whole washing machine is more safe and reliable, greatly reduces the frequency of maintenance and repair of the whole machine factory, and improves the goodwill of the manufacturer.

[0053] The utility model also provides a door lock protection accessory, the door lock protection accessory comprises: an overcurrent protection PTC, the two ends of the overcurrent protection PTC are respectively connected with two terminals of the door lock protection accessory; The PTC is a 2-pin PTC. The door lock protection accessory comprises at least two external terminals, so that the internal overcurrent protection PTC can be serially connected in the main circuit where the door lock is located, that is, the overcurrent protection PTC is connected in series with the main PTC to protect the door lock. By the door lock protection accessory, it is not realistic to return to the factory for the washing machine that has already been produced, and the door lock protection accessory provided by the embodiment can perfectly solve the problem: not only for the already produced The washing machine is over-current protected, and the cost is low. It is not necessary to make too many changes to the existing washing machine to make the washing machine safer. In the present embodiment, the overcurrent protection PTC also uses a ceramic PTC to improve the protection effect of the overcurrent PTC. Further in the present embodiment, the material composition of the overcurrent protection PTC is as described in the above embodiment.

[0054] In summary, in the overcurrent protection circuit provided by the present invention, a 2-pin overcurrent protection PTC is connected in series between the switching device and the load connection end, and the circuit is subjected to a large voltage impact, resulting in a circuit. The current in the circuit increases sharply. The resistance of the overcurrent protection PTC will increase sharply due to the temperature rise, which will quickly attenuate the current in the circuit to a small stable value, avoiding damage to components in the circuit. The safety of the circuit provides great assurance. This circuit uses only one over-current protection PTC, cleverly applies its characteristics, achieves low-cost, high-reliability protection of the door lock of the washing machine, greatly reduces the frequency of maintenance and repair of the whole machine factory, and improves the overall cost. Goodwill of the machine factory.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be It is included in the scope of protection of the present invention.

Claims

Claim

[Claim 1] An electric door lock protection circuit, wherein the protection circuit includes:

Serial connection device, overcurrent protection PTC and load connection;

The overcurrent protection PTC is a 2-pin, onboard PTC.

[Claim 2] The electrothermal door lock protection circuit according to claim 1, wherein the overcurrent protection PTC is a ceramic PTC.

[Claim 3] A washing machine control panel, wherein the control panel has a protection circuit for an electrothermal door lock;

The protection circuit is as claimed in any one of claims 1 to 2.

[Claim 4] A washing machine, comprising:

Washing machine body;

A control panel disposed in the body of the washing machine, the control panel being as claimed in claim 3.

[Claim 5] A washing machine electric door lock, characterized in that: the door lock comprises:

Overcurrent protection PTC, the overcurrent protection PTC is a 2-pin onboard PTC;

The overcurrent protection PTC-terminal is connected to the main PTC, and the other end is connected to the door lock terminal.

[Claim 6] The electric door lock of the washing machine according to claim 5, wherein the overcurrent protection P

TC is a ceramic PTC.

[Claim 7] A washing machine, comprising:

Washing machine body;

A door lock mounted on the body of the washing machine, the door lock being as claimed in any one of claims 5 to 6.

[Claim 8] A door lock protection accessory, wherein the door lock protection accessory comprises:

Overcurrent protection PTC, the overcurrent protection PTC is a 2-pin PTC, and the two pins of the overcurrent protection PTC are respectively connected to two terminals of the door lock protection accessory.

[Claim 9] The door lock protection accessory according to claim 8, wherein the overcurrent protection PTC is a ceramic PTC.