JP6423376B2 - Thermal protector with instantaneous interruption protection circuit and instantaneous interruption protection device - Google Patents

Description

  The present invention relates to an instantaneous interruption protection circuit for a thermal protector having a current interruption mechanism using inversion of a thermally responsive element and a thermal protector with an instantaneous interruption protection device.

  2. Description of the Related Art Thermal protectors that use bimetal have been conventionally used in power circuit protection devices such as electric motors and secondary batteries. For such a protection device, a contact open / close type thermal protector is used because of the advantages that high-precision operation setting is possible, the operation temperature can be set relatively freely, and the return operation can be repeatedly performed. As a basic configuration of the thermal protector, a first lead terminal having a fixed contact, a movable contact, a movable arm that presses the movable contact against the fixed contact, and a second electrically connected to the movable arm. Lead terminals, a bimetal that operates the movable arm so as to open and close the fixed contact and the movable contact in accordance with a temperature change, and a housing that houses these members. In recent years, as in the case of the thermal protector described in Patent Document 1, in addition to the basic configuration described above, PTC (positive characteristic circuit) is used as a heater that is energized when the movable contact and the fixed contact are separated and controls the return operation of the bimetal. Some are equipped with Mr. The thermal protector may be mounted in a narrow space such as a power supply unit of various electronic devices, and it is desirable that the thermal protector be as small and thin as possible. In particular, in recent years, there has been a demand for a compact and thin size of the thermal protector package size that is close to the limit in response to portable electronic devices that have been further miniaturized.

  For example, Patent Document 1 discloses that in a thermal protector (breaker 1) in which a fixed piece 3, a movable piece 2, an inversion-type thermal response element 4, and a PTC element (positive characteristic thermistor 5) are accommodated in a flat case 6. The characteristic thermistor 5 and the thermal responsive element 4 are sandwiched between the fixed piece 3 and the movable piece 2, the thermal responsive element 4 covers the upper surface 53 of the positive characteristic thermistor 5, and one side of the thermal responsive element 4 is reversed. There is disclosed a technique for realizing miniaturization by arranging each member in a stacked manner in a state where it contacts the positive characteristic thermistor 5 and the other surface contacts the movable piece 2.

JP 2005-129471 A

  The thermal protector has a movable contact in a casing container provided with a first lead having a fixed contact, a movable arm that presses the movable contact against the fixed contact, and a first electrically connected to the movable arm. Two leads, a thermally responsive element such as a bimetal that operates the movable arm so as to open and close the fixed contact and the movable contact with temperature change, and the second when connected to the first lead and the movable contact and the fixed contact are separated. A heating element such as a PTC element that is energized in contact with the lead to control the return operation of the thermally responsive element is accommodated, and the opening of the housing container is sealed with a lid. However, when a device equipped with a thermal protector falls during operation, the impact force when the bimetal or PTC element collides with the movable arm due to the impact of the fall, and the impact force of the movable arm is the elastic force of the movable arm. There was a fear of instantaneous interruption that the contact point was instantaneously released when the value exceeded the value, and the power supply from the power source was cut off for a very short time (several microseconds to several hundred microseconds). For example, in a small PC or a smart phone, an instantaneous power failure is likely to occur due to an impact when it is dropped during use. Instantaneous interruptions have the following adverse effects on portable devices such as small PCs and smart phones. For example, a program running on a computer holds data in a volatile memory that keeps storing only during energization. Therefore, there is a possibility that data may be lost if a power interruption occurs. In addition, although hard disks are non-volatile auxiliary storage devices, they are made precisely so if a momentary interruption occurs during reading or writing, there is a possibility that the recording medium may be damaged due to the arm contacting the recording medium. is there. In the case of a momentary interruption during communication, the connection between the two points at that time is disconnected, and it is often necessary to restart the connection from the handshake procedure in order to resume communication. In the case of a system that does not automatically perform such reconnection processing, the connection is disconnected at the time of the momentary disconnection, and reconnection is not performed, which greatly affects data exchange and the like.

  The present invention has been proposed in order to solve the above-described problems. In a thermal protector having a current interrupting mechanism by reversing a thermal responsive element, a contact is momentarily opened by receiving an external force such as a drop impact. Another object of the present invention is to provide an instantaneous interruption protection circuit for preventing a protected device of the thermal protector from instantaneously interrupting, and a thermal protector with an instantaneous interruption protection device.

  According to the present invention, a thermal protector that opens and closes a contact using a thermally responsive element and controls a return operation of the thermally responsive element using an attached first PTC (positive characteristic thermistor) element, and the thermal protector And a second PTC (positive characteristic thermistor) element electrically connected in parallel with each other. Even if the second PTC element constituting the instantaneous interruption protection circuit is mounted on an external substrate such as a printed wiring board on which the thermal protector is mounted,

  According to another aspect of the present invention, a package, a first electrode having a fixed contact provided in the package, a movable arm having a movable contact and pressing the movable contact against the fixed contact, A second electrode electrically connected to the movable arm, a thermally responsive element that operates the movable arm so as to open and close the fixed contact and the movable contact with temperature change, and the fixed contact and the movable contact connected to the first electrode are separated. A first PTC (positive characteristic thermistor) element that contacts the second electrode and is energized to control the return operation of the thermally responsive element, and in parallel with the contact pair consisting of the fixed contact and the movable contact A thermal protector with a momentary break protection device including a second PTC (positive temperature coefficient thermistor) element electrically connected is provided.

  In the thermal protector with a momentary break protection circuit and a momentary break protection device according to the present invention, the first PTC element is energized when the contact pair composed of the movable contact and the fixed contact is disconnected due to a temperature abnormality, and the abnormality is resolved. Until then, it has a function of controlling the return operation of the thermally responsive element using resistance heating. On the other hand, the second PTC element is used for energization compensation when a momentary interruption occurs in the contact pair of the thermal protector due to a drop impact of the apparatus. By providing the second PTC element in parallel with the contact pair composed of the movable contact and the fixed contact, even if the contact pair is instantaneously opened due to an impact such as dropping of the protected device, Since the PTC element forms a bypass path, energization of the protected device is maintained.

  A thermal protector with a momentary break protection circuit and a momentary break protection device according to the present invention includes a second PTC element connected in parallel to a contact pair of a fixed contact and a movable contact of the thermal protector, so that an impact at the time of dropping, etc. Even if the contact pair of the thermal protector is temporarily separated by this, the second PTC element forms a bypass path during that time, so that the energization can be maintained without impairing the protection function of the thermal protector and instantaneous interruption is prevented. To do. In addition, since the bypass path is composed of the PTC element, the function as a protection element of the thermal protector is not affected.

The circuit diagram of the instantaneous interruption protection circuit 10 which concerns on this invention is shown, (a) represents a circuit at normal time, (b) is the circuit of the state where the contact was instantaneously opened by receiving external force such as a drop impact. (C) represents a circuit in which the thermal protector is in a protective operation, and the thermal protector detects a temperature abnormality, and the thermally responsive element opens the contact pair and the first PTC element is energized to generate heat. Show. 1 shows a thermal protector 20 with a momentary break protection device according to the present invention, (a) shows a front cross-sectional view, and (b) shows a cover 21 of (a), a movable arm 25 and a thermal responsive element 27 removed. An overhead plan view is shown. 1 shows a thermal protector 30 with a momentary break protection device according to the present invention, (a) shows a front cross-sectional view, and (b) shows a cover 31 of (a), a movable arm 35, and a thermally responsive element 37 removed. An overhead plan view is shown. 1 shows a thermal protector 40 with a momentary break protection device according to the present invention, (a) shows a front sectional view, (b) shows a cover 41 of (a), a movable arm 45 and a thermally responsive element 47 removed. An overhead plan view is shown.

  As shown in FIG. 1, the instantaneous interruption protection circuit 10 according to the present invention includes a thermal protector having a thermal responsive element that opens and closes a contact and a first PTC element 11 that controls a return operation of the thermal responsive element. 12 and a second PTC element 13 electrically connected in parallel with the thermal protector 12. The thermally responsive element of the instantaneous interruption protection circuit 10 may be deformed or displaced at a predetermined temperature so that the contact can be opened and closed. For example, a bimetal, a shape memory alloy, or the like can be suitably used. Further, the mounting form of the second PTC element 13 according to the present invention is not limited as long as the parallel circuit shown in FIG. 1 can be configured. For example, the second PTC element 13 may be mounted in parallel on a substrate such as a printed wiring board. It may be incorporated in a part and incorporated.

  The thermal protector 20 with a momentary break protection device according to the present invention includes a package 21, a first electrode 23 having a fixed contact 22 provided on the package 21, and a movable contact 24, as shown in FIG. A movable arm 25 that presses and contacts the movable contact 24 against the fixed contact 22, a second electrode 26 that is electrically connected to the movable arm 25, and a movable contact 24 that opens and closes as the temperature changes. A heat-responsive element 27 such as a bimetal or a shape memory alloy that operates the arm 25, and a second electrode 26 that is connected to the first electrode 23 and is energized when the fixed contact 22 and the movable contact 24 are separated. 27 and a first PTC element 28 for controlling the return operation of the contact 27, and further electrically connected in parallel with a contact pair consisting of the fixed contact 22 and the movable contact 24 Comprising a second PTC element 29. In addition, the thermal protector with a momentary-break protection device of this invention should just be a protection element provided with the momentary-break protection circuit which concerns on this invention, The shape is arbitrary.

  The second PTC element 12 of the thermal protector with a momentary break protection circuit and a momentary break protection device according to the present invention may be anything as long as it does not hinder the trip operation and heat generation control of the first PTC element. For example, the room temperature resistance R2 of the second PTC element is preferably equal to or smaller than the room temperature resistance R1 of the first PTC element. Further, the trip temperature T2 of the second PTC element is preferably equal to or lower than the trip temperature T1 of the first PTC element. The room temperature resistance of the PTC element means an electric resistance value at 25 ° C.

  As shown in FIG. 1, the instantaneous interruption protection circuit 10 according to the first embodiment of the present invention includes a high thermal expansion metal material of Ni—Cr—Fe alloy and a low thermal expansion metal of Ni—Fe alloy for opening and closing contacts of an Ag alloy. A thermoresponsive element made of a bimetal laminated with a material, a first PTC element 11 having a room temperature resistance (R1) of 12Ω ± 30% and a trip temperature (T1) of 85 ° C. for controlling the return operation of the thermoresponsive element. And a second PTC element 13 having a room temperature resistance (R2) of 2.2Ω ± 20% and a trip temperature (T2) of 85 ° C. electrically connected in parallel with the thermal protector 12.

  The thermal protector 20 with the instantaneous interruption protection device according to the second embodiment of the present invention is a thermal protector in which the instantaneous interruption protection circuit 10 according to the first embodiment is mounted. As shown in FIG. A package 21 made of a lid that covers and seals, a Cu alloy first lead 23 having a fixed contact 22 made of Ag alloy, and a movable contact 24 made of Ag alloy. A movable arm 25 made of a resilient Cu alloy that presses and contacts the fixed contact 22, a Cu alloy second lead 26 electrically connected to the movable arm 25, and the fixed contact 22 and the movable contact as the temperature changes. A bar in which a high thermal expansion metal material of Ni—Cr—Fe alloy and a low thermal expansion metal material of Ni—Fe alloy that actuate the movable arm 25 to open and close 24 are laminated. A heat-responsive element 27 made of metal is connected to the first lead 23, and when the fixed contact 22 and the movable contact 24 are separated, the second lead 26 is contacted and energized to control the return operation of the heat-responsive element 27. And a second PTC element 29 electrically connected in parallel with the contact pair composed of the fixed contact 22 and the movable contact 24.

  Here, in order to compare the thermal protector with a momentary protection device of the present invention and the conventional thermal protector with the momentary protection, 20 smart phones mounted with the thermal protector 20 with the momentary protection device of Example 2 Prepare 20 smart phones equipped with a conventional thermal protector, charge each one, and with the power on, drop it once from the height of 1 meter from the 6th and 4 corners of the main unit to turn off the power. The number of occurrences of (momentary interruption) was counted. As a result, in the smart phone using the conventional thermal protector, instantaneous interruption occurred in 8 out of 20 units due to the drop impact. On the other hand, in the smart phone using the thermal protector 20 with the instantaneous interruption protection device of Example 2, no instantaneous interruption occurred.

  The present invention is not limited to the above-described embodiments, and various other modifications can be made without departing from the spirit of the present invention. For example, the thermal protector with a momentary break protection device according to the present invention, like the thermal protector 30 with the momentary break protection device in FIG. 3, the second PTC element 39 is connected to the second lead 36 and the lower side of the second lead 36. You may attach between the 1st lead | read | reed 33 extended | stretched. Moreover, you may accommodate the 2nd PTC element 49 in the package 41 like the thermal protector 40 with a momentary break protection apparatus of FIG.

  The instantaneous interruption protection circuit and the thermal protector with an instantaneous interruption protection device of the present invention can be used for protection devices for various power sources, for example, protection devices for secondary batteries such as power supply devices and battery packs.

10 ... Shutdown protection circuit,
11... First PTC element,
12 .... Thermal protector,
13. Second PTC element,
20, 30, 40... Thermal protector with momentary protection device,
21, 31, 41... Package,
22, 32, 42... Fixed contact,
23, 33, 43... First electrode (first lead),
24, 34, 44... Movable contacts,
25, 35, 45... Movable arm,
26, 36, 46... Second electrode (second lead),
27, 37, 47... Thermally responsive element,
28, 38, 48... First PTC element,
29, 39, 49... Second PTC element,
R1... Room temperature resistance value of the first PTC element,
R2... Room temperature resistance value of the second PTC element,
T1... Trip temperature of the first PTC element,
T2 .... Trip temperature of the second PTC element.

Claims (3)

  A package, a first electrode having a fixed contact provided on the package, a movable arm having a movable contact and pressing the movable contact against the fixed contact, and a second electrode electrically connected to the movable arm; A thermally responsive element that operates the movable arm to open and close the fixed contact and the movable contact in accordance with a temperature change, and the first contact when the fixed contact and the movable contact are separated from each other. A second PTC that is electrically connected in parallel with a contact pair that includes the fixed contact and the movable contact, and includes a first PTC element that is in contact with the two electrodes and is energized to control the return operation of the thermally responsive element. Thermal protector with momentary break protection device, characterized by having an element. The room temperature resistance of the second PTC element, room-temperature resistance and equal to or of the first PTC element, the instantaneous interruption protection device with Thermal protector according to claim 1, characterized in that it has a smaller electric resistance. The trip temperature of the second PTC element, wherein the first trip temperature and equal to or of the PTC element, instantaneous protection device with Thermal according to claim 1 or claim 2, characterized in that a lower temperature protector.

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