JP2003187684A - Thermal protector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal protector which can prevent thermally-actuated element from resonance and noise generated when vibration is received. <P>SOLUTION: A fixed contact point is arranged inside a sealed case, and a movable contact point mounted to a conductive movable piece housed inside the housing is made to contact with the fixed contact point by the spring action of the movable piece. It is constructed so as to make the movable piece deform in order to disengage the movable contact point from the fixed contact point when the thermally-actuated element reversely turns at a prescribed temperature, and the thermally-actuated element is pressed down to a prescribed part of the case in a state of not blocking the reverse turn of itself. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal protector having a structure in which a movable contact is separated from a fixed contact by a reversing action when a thermoresponsive element reaches a predetermined operating temperature.

[0002]

2. Description of the Related Art This type of thermal protector is generally used as a protection component for shutting off the circuit against overcurrent and overheat of secondary batteries used in various motors and equipment. For example, thermal protectors for secondary batteries such as mobile phones and notebook computers, thermal protectors for small motors, motors for automobiles, thermal protectors for DC circuits for protecting chargers, fans for air conditioners, electric washing machines, etc. It is used as a thermal protector for AC circuits used for general purpose motor protection.

FIG. 8 is a sectional view showing one form of a conventional thermal protector, and FIG. 9 is a partially exploded perspective view of the thermal protector of FIG. A fixed contact 2a, which is connected to a terminal 20a extending outside the case 1a, is provided at one end of the inner bottom surface of the case 1a in which the main body 10 is sealed with a lid 11. A protrusion 10a is formed at a position slightly closer to the other end than the center of the inner bottom portion of the main body 10, and a pair of guide pins 10b and 10b is formed at a position further closer to the other end than the protrusion 10a. Reference numeral 30a is a strip-shaped movable piece having elasticity and conductivity. The movable piece 30a is provided so as to project into the inside from the other end side of the case 1a, and the base end side thereof is the case 1a.
A terminal 30b is formed by extending from a, and a movable contact 3a, which comes into contact with the fixed contact 2a by its elasticity, is attached to the tip end portion. U-shaped notches 30c, 30c in a plan view are formed on both sides of a required portion of the movable piece 30a, and the guide pins 10b, 10b are guided in the notches 30c, 30c, respectively.

A thermo-responsive element is formed between the inner bottom surface of the case 1a and the movable piece 30a in a substantially convex spherical shape, in which a main bimetal 4b and an auxiliary bimetal 4c having different operating temperatures are vertically stacked. 4a is accommodated.
Notches 4d, 4d and 4e, 4e having a U-shape in plan view are formed on both sides of the base bimetal 4b and the auxiliary bimetal 4c on the base end side.
Are formed respectively, and these notches 4d, 4 are formed.
The guide pins 10b and 10b are respectively guided in e. A hole 4f is formed in almost the center of the auxiliary bimetal 4c.
Is formed, and the protrusion 10a formed on the inner bottom surface of the case 1a is guided through the hole 4f. 30c
Is a downward convex portion formed on the movable piece 30a so as to correspond to both end portions of the heat responsive element 4a.

The thermal protector shown in FIGS. 8 and 9 is installed in a required part of the equipment in a state where the terminals 20a and 30b are connected to other terminals such as a battery and an electronic board (not shown). In the installed state, when the temperature in the case rises due to overcurrent or overheating, and the temperature reaches or exceeds the operating temperature of the thermal responsive element 4a, the thermal responsive element 4a
However, due to the snap action, each movable contact 3a is reversed to the state in which it separates from the corresponding fixed contact 2a, and the current is cut off at that portion.

[0006]

By the way, in the equipment using the thermal protector, it is necessary to prevent or cut noise such as vibration noise or contact noise depending on the user's needs. For example, in the conventional thermal protector, since the thermal response element 4a is housed in the case 1 without being restrained at all, when the external vibration of the case 1 causes the thermal response element 4a to resonate. However, contact noise and vibration noise were often generated.
This contact sound not only causes discomfort, but also deteriorates the characteristics due to the deterioration of the contact portion due to resonance, which may reduce the reliability of the thermal protector. An object of the present invention is to provide a thermal protector capable of preventing resonance of a heat responsive element when subjected to vibration and the like, and preventing generation of noise.

[0007]

A thermal protector according to the present invention is configured as follows to solve the above-mentioned problems. That is, the thermal protector according to claim 1 has a sealed case, a fixed contact installed in the case and connected to a terminal outside the case, a movable contact at one end, and the other end being the case. A conductive movable piece that is connected to an external terminal and is housed in the case in a state where the movable contact is brought into contact with the fixed contact with a predetermined elastic force, and when the movable contact is reversed at a predetermined operating temperature, A thermoresponsive element housed in the case in a state in which the movable piece can be deformed so as to be separated from the fixed contact, and a part of the thermoresponsive element is moved to a predetermined portion of the case without hindering the reversal. It is characterized by being held down.

The thermal protector according to claim 2 is
Each has a sealed case, two fixed contacts installed in the case apart from each other and connected to each terminal outside the case, and movable contacts corresponding to the fixed contacts at both ends. A conductive movable piece housed in the case in a state in which the movable contact corresponding to the contact is brought into contact with a predetermined elastic force, and a fixed contact corresponding to each movable contact when the operation is reversed at a predetermined operating temperature. A heat responsive element housed in the case in a state in which the movable piece can be deformed so as to be separated from the heat responsive element, and a part of the heat responsive element is pressed to a predetermined portion of the case without hindering the inversion. It is characterized by

The thermal protector according to claim 3 is
The thermal protector according to claim 1 or 2, wherein the fixed contact is installed on an inner bottom portion of the case, and the thermoresponsive element is provided between the movable piece and a portion other than the fixed contact installation portion on the inner bottom portion of the case. It is characterized in that it is housed and is pressed by a pressing piece provided on the movable piece to a convex seat formed on the inner bottom of the case.

The thermal protector according to claim 4 is
The thermal protector according to claim 1 or 2, wherein the fixed contact is installed on an inner bottom portion of the case, and the thermoresponsive element is provided between the movable piece and a portion other than the fixed contact installation portion on the inner bottom portion of the case. The thermal storage device according to claim 1 or 2, wherein the thermal storage device is housed and is pressed by a pressing piece protruding from an inner top surface of the case to a convex seat formed on an inner bottom of the case. Protector.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a thermal protector according to the present invention will be described with reference to FIGS. First Embodiment FIG. 1 is a sectional view of a thermal protector according to a first embodiment, FIG. 2 is a sectional view showing a state in which a movable contact of the thermal protector of FIG. 1 is separated from a fixed contact, and FIG. 3 is a thermal protector of FIG. It is an exploded view excluding the heat responsive element of
(A) is a plan view of the case body, (b) is a plan view of the pressing plate, (c) is a plan view of the movable piece, and (d) is a fixed contact and its terminal and a terminal on the movable piece side. It is a top view of the mounting base which did.

The thermal protector of the first embodiment corresponds to claims 1 and 3. The flat case 1 having a horizontally rectangular shape in plan view is a bag-shaped main body 1 having an opening on the right end side in the figure.
0 and a mounting base 12 that is closely inserted into the main body 10 with the bottom surface closely contacting the inner bottom surface of the main body 10, and is a hermetically sealed state in the product state. Mounting base 1
2 is a lid-shaped side wall 14 that closes the opening of the main body 10 at the right end of the figure.
A peripheral wall 15 having a height corresponding to the inner height of the main body 10 is integrally formed on a part of the peripheral edge other than the lid-shaped side wall 14. As shown in FIG. 3D, the lid-shaped side wall 1
A shallow coupling groove 140 is formed on both sides of the groove 4, and the ridges 100 formed on both sides near the opening of the main body 10 are fitted in the groove 140.

A fixed contact 2 is embedded in one end of the inner bottom portion of the mounting base 12, and the fixed contact 2 is attached to the bottom of the mounting base 12 while being inserted into the outside of the case 1. The extended terminal 20 is connected. At the other end of the inner bottom portion of the mounting base 12, one end of another terminal 31 is embedded and the one end of the terminal 31 is provided with a plate-shaped movable piece 30 having elasticity and conductivity. The base ends are connected. The movable contact 3 is attached to the tip of the movable piece 30, and the movable contact 3 is in contact with the fixed contact 2 by the spring action of the movable piece 30 in a normal state.

A circular convex seat portion 13 is formed substantially at the center of a shallow circular recess 130 on the inner bottom of the mounting base 12. Between the upper surface of the convex seat portion 13 and the movable piece 30. The plate-shaped heat responsive element 4 is housed in. The heat responsive element 4 is substantially circular in a plan view and is formed into a convex spherical shape or an arcuate cross section, and when it is inverted at a predetermined operating temperature, the outer peripheral portion warps upward (concave spherical shape). To a concave arc shape in cross section).

The movable piece 30 is cut and raised so as to incline downward from the base end side toward the tip end side.
2 is formed, and the pressing piece 32 presses the heat responsive element 4 against the upper surface of the convex seat portion 13 to stabilize the attitude of the heat responsive element 4 in the accommodated state, and to prevent other parts of equipment not shown. Even if it vibrates, the heat responsive element 4 does not resonate with them. On the lower surface of the movable piece 30, downward convex portions 33, 33 are formed at positions corresponding to the inner inner peripheral position of the thermal actuator 4.

As shown in FIG. 3 (d), the terminal 20 connected to the fixed contact 2 and the terminal 31 connected to the movable contact 3 both extend in parallel from the opening side of the main body 1 of the case 1 to the outside. There is. In this embodiment, the slight protrusion 310 formed on the upper surface of one end of the terminal 31 is closely fitted into the mounting hole 34 formed on the base end side of the movable piece 30, and the two are joined together. In addition, the pressing plate 5 fixed on the joint between the two firmly fixes the joint.

As shown in FIG. 3 (d), the mounting base 1
Positioning pins 16 and 16 are formed at both ends of the inner bottom portion of the inner bottom portion 2 on the side of the lid-shaped side wall 14 so as to penetrate the terminals 31 and 20, respectively. The movable piece 30 and the pressing plate 5 have the guide holes 35, 35, 50, 50 formed therein.
Through (Figs. (C) and (b)), the guide pins 16, 16 are configured to guide them when they are attached.

The case 1 is made of, for example, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT) or other resin. The mounting base 12 is insert-molded together with these components so that the fixed contact 2, the terminals 20, 31 and the like are embedded. The mounting base 12 molded in this manner is tightly inserted (press-fitted) into the main body 10 after the movable piece 30 having the movable contact 3 and the thermoresponsive element 4 are housed in the state shown in FIG. After insertion, they may be further fixed and sealed with epoxy resin or the like.

The material of each of the terminals 20, 31 and the movable piece 30 is preferably phosphor bronze, for example, 8% (mass
%, The same applies hereinafter) is particularly preferred. However, the materials of these parts are copper and Cu-T.
i alloy, Cu-Be alloy, nickel silver, brass, Cu-Ni-S
A conductive material such as an i alloy may be used. The fixed contact 2 and the movable contact 3 are preferably made of nickel-silver alloy,
For example, a silver alloy containing 10% nickel is particularly preferable. However, the material of these parts may be a contact material such as a copper-silver alloy, a gold-silver alloy, a carbon-silver alloy, or a tungsten-silver alloy. For the thermal response element 4, for example, Cu-Ni
A material obtained by stacking a material on the high thermal expansion side made of an —Mn alloy and a material on the low thermal expansion side made of a Ni—Fe alloy is used. The material of the pressing plate 5 is preferably brass containing 35% zinc, for example, but other copper-based materials can also be used.

In the thermal protector of the first embodiment, when the current normally flows between the contacts, the movable contact 30 is pressed against the fixed contact 2 by the elasticity of the movable piece 30 as shown in FIG. is doing. When an abnormal current flows between the contacts or the temperature in the case 1 rises due to other causes, and the temperature in the case 1 reaches the operating temperature of the heat responsive element 4 or more, the heat responsive element 4 snaps. Turn over to warp upward. By the reversing operation of the thermal response element 4, as shown in FIG.
The movable contact 3 is separated from the fixed contact 2 to interrupt the current between the contacts.

According to the thermal protector of the first embodiment, the movable piece 30 is provided with the pressing piece 32 protruding to the lower surface side, and the thermal actuator 4 is pressed to the bottom side of the case 1 by the pressing piece 32. Therefore, it is possible to stabilize the attitude of the thermoresponsive element 4 in the housed state and prevent the thermoresponsive element 4 from resonating with other parts of the equipment (not shown) even if they vibrate. Therefore, it is possible to suppress the generation of noise such as contact noise and vibration noise. Since the pressing piece 32 is provided on the movable piece 30 as described above, a special installation space for the pressing piece 32 is not required, and the pressing piece 32 can contribute to manufacturing the whole in a smaller size. Further, since the thermoresponsive element 4 is pressed by the pressing piece 32 with a predetermined elasticity, the resonance of the thermoresponsive element 4 can be better prevented. As described above, the convex seat portion 13 is formed on the inner bottom portion of the case 1, and the heat responsive element 4 is pressed against the upper surface of the convex seat portion 13 by the pressing piece 32. The attitude of the element 4 in the housed state is more stable, and the resonance of the heat responsive element 4 can be prevented even better.

Second Embodiment FIG. 4 is a sectional view of a thermal protector according to a second embodiment, which is another form corresponding to claims 1 and 3. The case 1 is composed of a tray-shaped main body 10 that is open upward and a lid 11 that seals the main body 10. Lid 1
After insert-molding the main body 10 together with the fixed contact 20 and the terminals 20 and 31, 1 is hermetically bonded to the main body 10 by ultrasonic bonding or the like. A pressing piece 32 is formed on the movable piece 30 so as to incline downward from the front end side to the rear end side. The pressing piece 32 moves the lower thermal responsive element 4 to the upper surface of the convex seat portion 13 at the inner bottom of the case. It is pressing. The other configuration of the inner bottom surface of the case 1, the arrangement of each component and their related configurations, operations, and effects are almost the same as those of the thermal protector of the first embodiment, and therefore their description is omitted.

Third Embodiment FIG. 5 is a sectional view of a thermal protector according to a third embodiment, which corresponds to claims 1 and 4. The case 1 is composed of a tray-shaped main body 10 that is opened upward and a lid 11 that seals the main body 10, and a convex seat portion 13 is formed at an approximately central portion of an inner bottom portion of the main body 10. .
A fixed contact 2 is provided at one end of the inner bottom of the main body 10,
This fixed contact 2 is a terminal 20 extending outside the case 1.
Connected with. A strip-shaped movable piece 30 having a movable contact 3 in contact with the fixed contact 2 at its tip is attached by insert molding integrally with the main body 10 so as to project from the other end of the case 1. The base end side thereof extends to the outside of the case 1 to form the terminal 31.

The thermoresponsive element 4 is housed between the movable seat 31 and the convex seat portion 13 formed on the inner bottom portion of the case 1. On the inner top surface of the case 1 (lid 11), a projection-like pressing piece 32 is formed downward to almost the central portion, and the pressing piece 32 passes through a guide hole 36 formed in the movable piece 30 and is described above. By pressing the substantially central portion of the thermoresponsive element 4 against the upper surface of the convex seat portion 13, the vibration of the thermoresponsive element 4 is prevented. This embodiment has an advantage that the lid 11 is joined to the main body 10 of the case 1 and, at the same time, a vibration preventing structure for the heat responsive element 4 is formed. Other configurations and operational effects of the thermal protector of the third embodiment are almost the same as those of the thermal protector of the first embodiment, and therefore their explanations are omitted.

Fourth Embodiment FIG. 6 is a sectional view of a thermal protector according to a fourth embodiment, which corresponds to claims 2 and 3. The case 1 is composed of a tray-shaped main body 10 that is opened upward and a lid 11 that seals the main body 10. The case 1 includes a central portion of an inner bottom portion of the main body 10 and a central portion of an inner portion of the lid body 11. ,
The convex seat portions 13 and 17 are formed respectively.

Fixed contacts 2 and 2 are provided in an embedded manner at both ends of the inner bottom of the main body 10.
Each of the terminals 2 is connected to a corresponding terminal 20 extending outside the case 1. The movable piece 30 is accommodated in the case 1 in a state of being in contact with (slightly bulging) the lower surface of the convex seat portion 17 of the lid 11. The movable piece 30 is formed so as to have a substantially convex arcuate shape in cross section.
The movable contacts 3 and 3 are attached so as to come into contact with the corresponding fixed contacts 2 by the spring action thereof. Between the inner bottom portion of the main body 10 and the movable piece 30, a thermo-responsive element 4 formed in a convex spherical shape or a convex arc shape in section is housed, and the thermo-responsive element 4 is located substantially at the center of the movable piece 30. It is pressed against the circular seat portion 13 by a pressing piece 32 which is formed in a downwardly sloping shape.

In the thermal protector of the fourth embodiment, when the temperature of the installation site rises due to overcurrent or overheating in the installed state and the temperature reaches the operating temperature of the thermal responsive element 4 or higher, the thermal responsive element 4 is Due to the snap action, it is reversed so as to warp in the opposite direction. By this inversion, the movable piece 30 is deformed into a state in which the movable contacts 3 and 3 are separated from the corresponding fixed contacts 2 and 2, so that the current between the contacts is interrupted. Other configurations and operational effects of the thermal protector of the fourth embodiment are almost the same as those of the thermal protector of the first embodiment, and therefore their description is omitted.

Fifth Embodiment FIG. 7 is a sectional view of a thermal protector according to a fifth embodiment, which corresponds to claims 2 and 4. A projecting pressing piece 32 is formed in a downward direction on a convex seat portion 17 formed substantially in the center of the inside of the lid 11 of the case 1 (the inner top surface of the case). Movable piece 3
The heat responsive element 4 passes through the guide hole 36 formed to 0.
By pressing the substantially central portion of the above on the upper surface of the convex seat portion 13, the vibration of the heat responsive element 4 is prevented. In this embodiment, by joining the lid 11 to the main body 10 of the case 1, the postures of the movable piece 30 and the thermal responsive element 4 are strongly regulated, and at the same time, a vibration prevention structure for the thermal responsive element 4 is configured. There is. Other configurations and operational effects of the thermal protector of the third embodiment are almost the same as those of the thermal protector of the first embodiment, and therefore their explanations are omitted.

Other Embodiments In each of the above-mentioned embodiments, the movable piece 30 or the pressing piece 32 provided on the inner top surface of the case 1 holds a part of the thermal responsive element 4. However, in the present invention, the thermal responsive element is used. As long as a part of the element 4 is pressed against a predetermined part of the case without hindering the reversal, the element 4 can be implemented without using the pressing piece 32. Further, if the pressing piece 32 is configured to press a part of the heat responsive element 4 to the case 1 side so as not to prevent the reversal of the heat responsive element 4, the pressing piece 32 may be provided even in another part of the case 1. it can. The pressing piece 32 provided on the movable piece 30 may be mounted by welding or screwing so that an appropriate metal plate is projected to the lower surface of the movable piece 30 and inclined downward from any direction. For example, the movable piece 30 may be formed so as to project downward by pressing a part of the movable piece 30 in a concave shape. A pressing piece 32 provided on the inner top surface of the case 1
The other member may be attached to the inner top surface of the case 1 by an appropriate means.

[0030]

According to the thermal protector of the first and second aspects of the present invention, a part of the thermoresponsive element in the case is pressed to a predetermined part in the case without hindering its reversal. It is possible to stabilize the attitude of the heat-responsive element in the accommodated state and prevent the heat-responsive element from resonating with other parts of the equipment even when they vibrate. Therefore, it is possible to suppress the generation of noise such as contact noise and vibration noise.

According to the thermal protector of the third aspect of the present invention, since the heat responsive element has a structure of being held by the holding piece provided on the movable piece, it is special for holding the heat responsive element to a predetermined portion in the case. It does not require a large space and contributes to the manufacturing of the entire device in a smaller size. Further, since the pressing piece has elasticity and presses the heat responsive element against the convex pedestal at the inner bottom portion of the case, it is possible to further prevent vibration of the heat responsive element.

In the thermal protector according to the fourth aspect of the present invention, since the heat responsive element is pressed against the convex seat portion by the pressing piece provided on the inner top surface of the case, the heat responsive element is provided at a predetermined portion in the case. It does not require a special space for holding down, and contributes to the manufacturing of the whole in a smaller size.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermal protector according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where a movable contact of the thermal protector shown in FIG. 1 is separated from a fixed contact.

FIG. 3 is an exploded view of the thermal protector of FIG. 1 excluding a heat responsive element, and FIG. 3 (a) is a plan view of a case body;
(B) is a plan view of the pressing plate, (c) is a plan view of the movable piece, and (d) is a plan view of the mounting base on which the fixed contact and its terminal and the terminal on the movable piece side are installed.

FIG. 4 is a sectional view of a thermal protector according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a thermal protector according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a thermal protector according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a thermal protector according to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing one form of a conventional thermal protector.

9 is a schematic exploded perspective view of the thermal protector of FIG.

[Explanation of symbols]

1 case 10 body 11 lid 12 mounting base 13,17 convex seat 130 recess 14 Lid-shaped side wall 15 Perimeter wall 16 guide pins 2 fixed contacts 3 movable contacts 20,31 terminal 310 Convex part 30 movable pieces 32 holding piece 33 convex 34 Mounting hole 35, 36 guide hole 4 Thermal response element 5 holding plate 50 guide holes

Continued front page    (72) Inventor Takeshi Nagai             528-5 Furukawa, Shin-Hosio-cho, Kiyotaki, Nikko, Tochigi Prefecture             Precision Metal Industry Co., Ltd. F term (reference) 5G041 AA13 AA20 BB06 BB08 BB11                       CC01 CE04 CE06 DA11 DB01

Claims (4)

[Claims] 1. A sealed case, a fixed contact installed in the case and connected to a terminal outside the case, a movable contact at one end, and the other end connected to a terminal outside the case, A conductive movable piece housed in the case in a state where the movable contact is brought into contact with the fixed contact with a predetermined elastic force, and the movable contact is separated from the fixed contact when the movable contact is reversed at a predetermined operating temperature. A heat responsive element housed in the case in a state in which the movable piece can be deformed, and a part of the heat responsive element is pressed to a predetermined portion of the case without hindering the inversion. A thermal protector characterized by that. 2. A sealed case, two fixed contacts installed in the case in a state of being separated from each other and connected to respective terminals outside the case, and movable contacts corresponding to the fixed contacts at both ends. And a movable movable piece housed in the case in a state where the movable contact corresponding to each fixed contact is brought into contact with a predetermined elastic force, and each movable contact when performing a reversing operation at a predetermined operating temperature. A thermoresponsive element housed in the case in a state in which the movable piece can be deformed so as to be separated from the corresponding fixed contact, and a part of the thermoresponsive element does not hinder the inversion. The thermal protector is characterized in that it is pressed down to a predetermined part of. 3. The fixed contact is installed on the inner bottom of the case, and the thermoresponsive element is housed between the movable piece and a part of the inner bottom of the case other than the fixed contact installation part, and The thermal protector according to claim 1 or 2, wherein a pressing piece provided on the movable piece is pressed against a convex seat portion formed on an inner bottom portion of the case. 4. The fixed contact is installed on an inner bottom portion of the case, the thermoresponsive element is housed between the movable piece and a part of the inner bottom portion of the case other than the fixed contact installation portion, and The thermal protector according to claim 1, wherein the thermal protector is pressed by a pressing piece protruding from an inner top surface of the case to a convex seat portion formed on an inner bottom portion of the case.