JPH07230748A - Resistance thermal fuse - Google Patents

Abstract

PURPOSE:To perform an operation with no difference of a thermal fuse element based on heating each film resistor by providing the thermal fuse element in the center of an insulating base, and providing the film resistors of different resistance value in the right/left so as to interpose this thermal fuse element. CONSTITUTION:A thermal fuse element 14 is provided in the center of one surface of a heat conductive insulating base 11, and two film resistors 17 of different resistance value are provided in the other surface in a manner wherein the thermal fuse element 14 is interposed, to constitute a resistance thermal fuse main unit 1 by respectively connecting lead wires 13, 19. A case 2 comprising a right/left asymmetrical plate part 21, having a bulging part 20 in an intermediate part, and a frame edge is provided covering in a closely fitted condition in the resistance thermal fuse main unit 1 so as to receive the fuse element in the bulging part 20, and an insulating material 3 is injected into the case 2 and solidified. In this way, an operation of the thermal fuse element 14, based on heating each film resistor 17, is performed with no time difference, to surely protect a circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance / temperature fuse in which a resistor is incorporated in a substrate type alloy type temperature fuse.

[0002]

2. Description of the Related Art In a resistance / temperature fuse, an alloy type temperature fuse element and a resistor are integrated in close proximity, and the temperature fuse element is melted by heat generated due to overcurrent in the resistor. To shut off the overcurrent.

Conventionally, as a substrate type resistance / temperature fuse,
The double-sided type shown in FIGS. 6A to 6D is known. Figure 6 (a) shows this double-sided board type resistor.
6B is a plan view of the temperature fuse, FIG. 6B is a bottom view of the same, and FIG. 6C is a view of FIG. 6A.
C is a cross-sectional view, and (d) of FIG. 6 is a cross section in (b) of FIG.
D cross-sectional views are shown, respectively, and a pair of temperature fuse membrane electrodes 12 'and 12' are printed on one surface of the heat conductive insulating substrate 11 'so as to coincide with the vertical center line aa, and between the electrodes. A low melting point metal piece 14 'serving as a temperature fuse element is bridged, a flux 15' is applied to the low melting point metal piece 14 ', and a vertical center line a- is formed on the other surface of the insulating substrate 11'. a
2 pairs of resistor film electrodes 16'-1 symmetrically with respect to
6 ', 16'-16' are printed, and a film resistor 17 'is bridged between these respective counter electrodes by baking onto the insulating substrate 11' (18 'is a protective layer of the film resistor), and each electrode 12 '(1
6 ') is connected to a lead wire 13' (19 '), and a curable resin layer 3'such as an epoxy resin is coated on the entire surface of the insulating substrate 11' by a dip coating method.

In this resistance / temperature fuse, one film resistor is inserted in one part of the circuit and the other film resistor is inserted in another part of the circuit for the electric circuit to be protected. It is used by inserting and connecting a fuse element to the input end of the circuit, and when an overcurrent flows through one of the membrane resistors and the membrane resistor generates heat, the generated heat causes the temperature fuse element to melt. Then, the power supply to the circuit is cut off.

[0005]

SUMMARY OF THE INVENTION The above resistance / temperature fuse
In this case, the resistance value of the film resistor may differ due to the restriction of the circuit impedance of each circuit portion in which each film resistor is inserted and connected. Therefore, if the heat transfer path of the medium from each film resistor to the temperature fuse element is completely symmetrical, even if an overcurrent of the same value flows to each resistor, the resistance of the film resistor having a small resistance value The operating time of the temperature fuse element based on the heat generation is longer than the operating time of the temperature fuse element based on the heat generation of the membrane resistor having a large resistance value, and the imbalance of the operating time cannot be avoided.

Such an imbalance is caused by the heat transfer between the film resistor having a small resistance value and the temperature fuse element, and the heat transfer between the film resistor having a large resistance value and the temperature fuse element. It can be eliminated by adjusting it to be higher than the sex. Therefore, the heat transfer property varies depending on the volume of the heat transfer medium existing between the film resistor and the temperature fuse element, and as a means for eliminating this imbalance, a film resistor having a small resistance value is used. Adjusting the heat transfer property by making the volume of the heat transfer medium between the temperature fuse element and the membrane resistor having a large resistance value smaller than the volume of the heat transfer medium between the temperature fuse element and the temperature fuse element. However, it is difficult to carry out the above-mentioned resistance / temperature fuse which uses a dip coating method in which it is difficult to form a fixed insulating coating.

An object of the present invention is to provide a resistance / temperature fuse in which a temperature fuse element is provided in the center of an insulating substrate and a film resistor having different resistance values is provided on the left and right sides of the temperature fuse element. In the above, the operation of the temperature fuse element based on the heat generation of each film resistor is performed without any substantial difference.

[0008]

In a resistance / temperature fuse according to the present invention, a temperature fuse element and two film resistors having different resistance values are provided on a heat conductive insulating substrate. The main body of the resistance / temperature fuse thus formed is covered with a heat transfer adjusting case, and an insulating material is injected and solidified in the case, so that the resistance of each film resistor can be improved under the same overcurrent. The operating time of the temperature fuse element based on heat generation is made substantially equal, and more specifically, the temperature fuse element is provided at the center of one surface of the heat conductive insulating substrate. A resistance / temperature fuse main body, in which a film resistor having different resistance values is provided symmetrically with respect to the temperature fuse element on the other surface of the substrate, has a frame edge around the plate portion. A transmission adjustment case is installed on the plate of the temperature fuse Be decorated by placement into cement side, 該Ke -
The insulating material is injected and solidified in the case, and the plate portion of the case is controlled so that the operating time of the temperature fuse element based on the heat generation of each film resistor under the same overcurrent is almost equal. A structure characterized by being asymmetrical, or a temperature fuse element is provided on one side of the heat conductive insulating substrate, and two different temperature fuse elements are placed on the other side of the substrate to have different resistance values. A resistance / temperature fuse main body provided with a film resistor is covered with a heat transfer adjusting case, an insulating material is injected and solidified in the case, and under the same overcurrent. The structure is characterized in that the distance between each film resistor and the temperature fuse element is different so that the operating time of the temperature fuse element based on the heat generation of each film resistor is made substantially equal. Even in the concrete configuration of, the left and right parts of the plate part of the case Resistance Temperature fuse - brought close to one side of's body of the insulating substrate, the temperature fuse in the intermediate bulge portion of the balance - it is preferable to accommodate the's elements.

The structure of the present invention will be described below with reference to the drawings. 1A is a plan view of the resistance / temperature fuse main body used in the present invention, FIG. 1B is a bottom view of the same, and FIG. 1C is similar to FIG. 1A. 1 is a sectional view taken along the line of FIG. 1, and FIG. 1D is a sectional view taken along the line of FIG.

In FIGS. 1A to 1D,
Reference numeral 11 denotes a heat conductive insulating substrate, and a ceramic substrate is suitable. Reference numerals 12 and 12 denote a pair of membrane electrodes provided at a central position on one surface of the insulating substrate 11, and the lead wire mounting portion 1
21 and a temperature fuse element mounting portion 122,
Membrane electrodes symmetrically arranged with respect to the vertical centerline aa are arranged vertically symmetrically with respect to the horizontal centerline bb. The membrane electrode 12 can be used by a printing method, for example, a screen printing of a conductive paint and baking it. Reference numeral 13 is a lead wire welded or brazed to each membrane electrode 12. 14
Is a temperature fuse element bridged along the longitudinal centerline aa by welding between the membrane electrodes, and is a low melting point fusible alloy of round wire or square wire (for example, flattened round wire). Wires are used. 15 is a temperature fuse element 1
No. 4, which has a rosin as a main component.

Reference numerals 16, 16, 16 and 16 denote two pairs of membrane electrodes, which are symmetrically provided with respect to the longitudinal centerline aa on the left and right portions of the other surface of the insulating substrate 11, and have a lead at one end. The strip-shaped films 162 having the wire attachment portions 161 are vertically symmetrical with respect to the lateral center line, and the lead wire attachment portions 161 are located on the left and right ends of the insulating substrate 11. The membrane electrode 16 is also formed by the printing method described above. Reference numeral 17 denotes a film resistor that is burned on the other surface of the insulating substrate 11 across the pair of film electrodes 16 and 16 and is made of a resistive paint (resistive particles and binder).
A powder of a metal oxide or a powder of a high resistance metal such as nickel or iron can be used as the resistance particles, and a glass frit can be used as the binder). This film resistor is symmetrical about the temperature fuse element, and its resistance value is made different by trimming with different cutting distances. 1
Reference numeral 8 denotes a protective film provided so as to cover both the film resistors 17, and a glass frit having a melting point lower than that of the glass frit is used, and a film frit of the film resistor when adjusting the resistance value of the film resistor by trimming It is effective in preventing the occurrence of cracks. Reference numeral 19 is a lead wire connected to the membrane electrode 16 by welding or brazing.

FIG. 2A is a sectional view showing an example of the resistance / temperature fuse according to the present invention, and FIG. 2B is a sectional view taken along the line RO in FIG. In (a) of FIG. 2 and (b) of FIG. 2, 1 is the main body of the resistance / temperature fuse described above. 2 is the case (also shown in FIG. 3)
In addition, a frame edge 22 is provided around a plate portion 21 having a laterally asymmetrical shape (a roll is a center line) in which a middle portion is bulged, and
The temperature fuse element 1 is applied to the temperature fuse element 1, and the temperature fuse element 14 side of the resistance / temperature fuse element 1 is exposed to the plate portion 21 of the case 2.
4 is housed in the bulging portion 20, and the left and right portions 211 and 212 of the plate portion 21 are close to one surface of the insulating substrate 11. Further, the lead wires 13 and 19 are drawn out from the respective V notches 221 provided on the frame edge 22.

The inner edge of the frame edge 22 of the case 2 is set so that the outer edge of the insulating substrate 11 of the resistance / temperature fuse main body 1 can be fitted tightly without leaving a gap substantially.
The vertical dimension and the horizontal dimension of the inner contour are 1.1 times or less, preferably 1.07 times or less, of the vertical dimension and the horizontal dimension of the insulating substrate, respectively. An insulating material 3 is injected and solidified into the case 2. The case 2 is filled with an epoxy resin liquid having a viscosity of about 20,000 to 200,000 cps.
Weighed and dropped into it and cured.

In FIG. 2A, if the resistance value (R ₁ ) of the film resistor 17 on the left side is larger than the resistance value (R ₂ ) of the film resistor 17 on the right side, for example, Heat transfer Z from the membrane resistor to the temperature fuse element 14
₁ (where r is the heat resistance of the heat transfer medium path from the film resistor to the temperature fuse element and c is the heat capacity, heat is transferred faster as r is lower and c is smaller, and the heat transferability is rc.
To be lower than the heat transferability Z ₂ from the membrane resistor on the right side to the temperature fuse element 14 (to be R ₁ Z ₁ = Z ₂ R ₂ ). -G part 2
The central position p of the bulging portion 20 of 1 is shifted to the side of the high-resistance film resistor so that the plate portion 1 is left-right asymmetric with respect to the central line.

In the above configuration example, the bulging portion is formed so as to be displaced with respect to the left and right center point of the case to make the case bilaterally asymmetrical, but the bilaterally asymmetrical configuration is limited to this. Not a thing. In the above configuration example, the thickness of the film resistor 17 including the protective layer 18 is smaller than the diameter d of the lead wire 19, and the flux application temperature fuse element 14 is used.
Is larger than the diameter d of the lead wire 13, the required insulation thickness on the lead wire 19 of the membrane resistor 17 is t, the thickness of the insulating substrate 11 is e, and the thickness of the membrane electrode is If it is e ',
Height T ₁ of the swell 2 up to the upper surface inside the bulging portion 20 (FIG. 3)
Is slightly larger than T in the following equation: T = t + h + d + e The height T ₂ of the left and right parts in the case (FIG. 3) is T ′ in the following equation.
It is set slightly larger than. T '= t + d + e + e'

FIG. 4 is a sectional view showing a constitutional example of a resistance / temperature fuse according to the invention of claim 4. In this configuration example, for example, in FIG.
The resistance value (R ₁₎ is the resistance value of the right-film resistor 17 (R ₂₎
Is said to be larger than. Therefore, in order to operate the temperature fuse element 14 without imbalance against the heat generation of the left and right membrane resistors under the use of the symmetrical flat case 2, the left membrane resistor 17 is operated. The distance L ₁ to the temperature fuse element 14 is made larger than the distance L ₂ to the temperature fuse element 14 from the membrane resistor 17 on the right side so that the heat from the membrane resistor on the left side to the temperature fuse element is increased. The transferability Z ₁ and the heat transferability Z ₂ from the membrane resistor on the right side to the temperature fuse element are adjusted so as to satisfy the relationship of Z ₁ / Z ₂ = R ₂ / R ₁ as much as possible. There is.

In FIG. 4, (a) and (b) of FIG.
, The same reference numerals indicate the same components. 11 is a thermally conductive insulating substrate, and 14 is a temperature fuse.
Element, 15 is a flux, 17 is a membrane resistor, 18 is a protective layer, 19 is a lead wire of the membrane resistor.
Indicates an insulating material injected into the case 2 and solidified therein, for example, an epoxy resin, and a lead of the temperature fuse element.
Lines do not appear in the figure.

Also in this configuration example, the thickness of the film resistor 17 including the protective layer 18 is smaller than the diameter d of the lead wire 19, and the height h of the flux applying temperature fuse element 14 is the temperature. It is larger than the lead wire diameter d of the fuse element, the required insulation thickness on the lead wire 19 of the membrane resistor 17 is t, the thickness of the insulating substrate 11 is e, and the thickness of the membrane electrode is e. Then, the height T _{3 of the case} 2 is set to T ₃ ≧ t + h + d + e + e '.

As shown in FIG. 5, the left and right portions of the plate portion 21 are brought close to the insulating substrate 11 of the main body 1 and the intermediate portion 20 is swollen, instead of the symmetrical flat case. Use case 2 (center line is c-c line) and use flux 1
The temperature fuse element 14 coated with No. 5 may be housed in the intermediate bulging portion 20.

In any of the above-mentioned constitutional examples, a press-molded product of a metal such as aluminum or stainless steel can be used as the case in addition to the electric insulator, but the V notch and the relieve of the case frame edge can be used. -From the viewpoint of ensuring insulation from the wire, electrical insulation, especially plastic, such as thermosetting resins such as epoxy resin, unsaturated polyester, vinyl ester resin, phenol resin, polyvinyl chloride, chlorinated Such as polyvinyl chloride, polyethylene, polypropylene, acrylonitrile-butadiene-styrene copolymer, polystyrene, polycarbonate, polyamide, polyvinylidene fluoride, polyphenylene sulfide, polysulfone, and thermoplastic resins such as polyether ether ketone. It is preferred to use injection molded articles.

The dimensions of each part of the resistance / temperature fuse are usually set as follows. That is, the length of the insulating substrate (direction of the temperature fuse element): 5 to 12 m
m, horizontal dimension: 6-18 mm, thickness 0.5-1.5 m
m, thickness of membrane electrode: 10 to 80 μm, thickness of membrane resistor:
10 to 35 μm, thickness of protective layer: 20 to 200 μm, diameter of temperature fuse element: 0.3 to 1.0 mm, coating thickness of flux from substrate on temperature fuse element: 0.4 to 2 mm, Lead wire diameter: 0.3-1.
3 mm, thickness of the insulation material of the membrane resistor lead wire (t in FIGS. 2 and 5): 0.1 to 2 mm, inner case: 1.005 to 1.1 times the outer dimension of the substrate, Case thickness: 0.1
~ 1.6 mm, the height in the case is the above,
Set by expression. In the present invention, the temperature fuse element and two film resistors having different resistance values may be provided on the same surface of the heat conductive insulating substrate. Further, the case may be covered with the plate portion facing up or down.

Thus, (1) a temperature fuse element is provided at the center of one surface of the heat conductive insulating substrate, and film resistors having different resistance values symmetrically with respect to the temperature fuse element are provided on the same surface. The resistance / temperature fuse main body to be provided is covered with a heat transfer adjusting case having a frame edge around the plate portion, and an insulating material is injected and solidified in the case to form a case. Pre-
The asymmetrical shape of the heat conducting element so that the operating time of the temperature fuse elements based on the heat generation of each film resistor under the same overcurrent is almost equal. A temperature-fuse element on one side, and two film resistors with different resistance values sandwiching the same-temperature fuse element on the same side, and a heat transfer adjustment case on the main body of the resistance / temperature fuse. And inject and solidify an insulating material into the case, so that the operating time of the temperature fuse elements based on the heat generation of each film resistor under the same overcurrent is made substantially equal. It is also possible to make the distance between the body and the temperature fuse element different.

In the present invention, the space between the plate portion of the case and the insulating substrate of the main body of the resistance / temperature fuse is usually filled with the above-mentioned insulating material, but it is also possible to form a gap. Is.

In the resistance / temperature fuse according to the present invention,
For the electrical circuit to be protected, one membrane resistor is inserted and connected to one part of the circuit, and the other membrane resistor is inserted and connected to the other part of the circuit, and the temperature fuse element is inserted and connected to the input end of the circuit. Used by.

When the resistance values of the respective film resistors are R ₁ and R ₂ ,
The heat generated by each film resistor due to the same overcurrent i is R ₁ i ² , R ₂
i ² and R ₁ i ^{2 where} Z ₁ and Z ₂ are the heat transfer properties of the heat transfer path from each film resistor to the temperature fuse element.
When Z ₁ = R ₂ i ² · Z ₂ is satisfied, the temperature fuse elements can raise the temperature almost the same despite the difference in the amount of heat generated by each film resistor, and despite the difference in resistance value. No
The operating time of the temperature fuse elements based on the heat generation of each film resistor under the same overcurrent can be made almost equal.

Although the heat transfer property of the heat transfer path from the film resistor to the temperature fuse element can be adjusted by the distance between them and the amount of the heat transfer medium, the resistance / temperature fuse main body is immersed. When coating with a coating method, it is difficult to keep the volume of the coating layer constant, and the temperature of each film resistor is
It is extremely difficult to make adjustments with sufficient accuracy for the heat transfer properties of the heat transfer path to the element.

However, in the resistance / temperature fuse of the present invention, the case where the regularity can be well ensured by injection molding or the like.
Since it is possible to cover the resistance and temperature fuse body with the main body and inject and solidify the insulating material by metering and dropping it into the case, the heat transfer can be adjusted with high accuracy and the same. The operating time of the temperature fuse elements based on the heat generation of each film resistor under an overcurrent can be made sufficiently equal.

According to the third and fifth aspects of the invention, the flux coating fuse element having a large thickness on one side of the insulating substrate is housed in the bulging portion of the case, and one side of the substrate is provided. Since the remaining portion of the above is close to the inner surface of the case, the amount of the medium therebetween can be remarkably reduced, and the heat capacity c can be reduced to improve the quickness of operation as a whole.

[0028]

【Example】

Example 1 The configurations shown in (a) of FIG. 2 and (b) of FIG. 2 were used, and the configurations shown in (a) to (d) of FIG. 1 were used for the main body of the resistance / temperature fuse. . The thermal conductive insulating substrate
A ceramic substrate having a thickness of 0.6 mm, a length of 9 mm, and a width of 14 mm was used, and all the membrane electrodes were formed by printing and baking silver paste, and the electrode thickness was set to 25 μm. The temperature fuse element has a diameter of 0.5 mm and a liquidus temperature of 96 ° C.
The low melting point fusible alloy wire was used and the coating thickness of the flux (having a softening point lower than the melting point of the fuse element) was 1.2 mm. The film resistor has a thickness of a metal oxide resistance paint (a mixture of metal oxide powder and glass frit) of 2
By printing and baking 0 μm, the protective film is formed by baking low melting point glass frit with a thickness of 80 μm, and the distance from the temperature fuse element to each film resistor is 0.5 mm. The resistance value of 1 was set to 1 kΩ and 950Ω by trimming. A copper wire having a diameter of 0.6 mm was used for all the lead wires.

The case is an injection-molded product of phenol resin, and in FIG. 3, the internal height T ₁ to the bulge portion is 2.7.
mm, each internal height T _{2 of} the left and right parts is 1.5 mm, the width w _{0 of the} bulging part is 6.3 mm, and the widths w ₁ and w _{2 of} the left and right parts are 3.5 m
m and 5.1 mm, the inner vertical length is 9.7 mm, and the thickness is 0.
An epoxy resin solution for dip coating was used as the curable insulating material.

Of the 40 products of these examples, for 20 of them, a film resistor having a resistance value of Ω and a temperature fuse element were connected in series, and a current 94 equivalent to 9 times the rated power (1 W) was obtained. When the operating time (time from the start of energization to the time when the energization is cut off) was measured by flowing 0.4 mA,
It was 20 to 23 seconds. Further, for the remaining 20 pieces, a membrane resistor having a resistance value of 950Ω and a temperature fuse element were connected in series, and the operating time was measured in the same manner under the same current as above. It was 2 seconds to 23 seconds, and the operating time of the temperature fuse elements based on the heat generation of each film resistor under the same overcurrent could be made substantially equal.

Comparative Example 1 Using the same resistance / temperature fuse main body as in Example 1, the epoxy resin used in Example 1 was dip coated on the insulating substrate. When the operating time of the temperature fuse element for each film resistor was measured in the same manner as in Example 1, the operating time was 19 seconds to 29 seconds and 22 seconds to 32 seconds, and the operating time was about 3 seconds. There was a difference.

Example 2 Using the configuration shown in FIG. 5, with respect to the resistance / temperature fuse main body used in Example 1, the distance between the membrane resistor having a resistance value of 1 kΩ and the temperature fuse element was only 1 mm. The resistance / temperature fuse main body was used in the same manner as in Example 1 except that the width of the insulating substrate was increased correspondingly by shifting in the separating direction. The case is made of symmetrical phenol with the center part bulged, and the height T ₃ to the inner surface of the bulge part is 2.7 mm, the height T ₂ inside the left and right parts is 1.5 mm, The width w ₀ inside the projection is 6.
3 mm, the inner width w ₃ of the right and left portions using 4.3 mm, those vertical length of the inner contour is 9 mm, a thickness of 0.6 mm, Example 1
Similarly to, the epoxy resin liquid was injected and solidified by the dropping method.

For each of the 40 products of this embodiment, as in the case of the first embodiment, each film resistor and the temperature fuse element are connected in series, and the operation is performed under a current of 94.4 mA. When the time was measured, it was 20 seconds to 24 seconds for all the film resistors, and the variation in the operating time was negligible as in Example 1.

[0034]

The resistance / temperature fuse of the present invention has the structure as described above, and the temperature fuse element is provided at the center of the insulating substrate, and the resistance value is different between the right and left sides of the temperature fuse element. In a resistance / temperature fuse provided with each film resistor, a temperature fuse based on heat generation of each film resistor
It is possible to guarantee that the element operation is performed without a substantial time difference, and the circuit can be reliably protected even if an overcurrent flows through any of the membrane resistors.

[Brief description of drawings]

FIG. 1A shows a resistor used in the present invention.
A plan view showing an example of the temperature fuse main body, (b) of FIG. 1 is a bottom view of the same, (c) of FIG. 1 is a sectional view taken along the line of (a) of FIG. 1, and (d) of FIG. 1 in (b) of FIG.
FIG.

FIG. 2A is a sectional view showing a configuration example of the present invention according to claim 3, and FIG. 2B is a sectional view taken along line A-B in FIG.

FIG. 3 is an explanatory diagram showing a case in the configuration example of FIG.

FIG. 4 is a cross-sectional view showing a configuration example of the present invention according to claim 4.

FIG. 5 is a sectional view showing a configuration example of the present invention according to claim 5.

6 (a) is an explanatory plan view showing a conventional example, and FIG.
Similarly, (B) is a bottom view, (C) of FIG. 6 is a sectional view taken along the line of (A) of FIG. 6, and (D) of FIG. 6 is a sectional view of the line of (B) of FIG. is there.

[Explanation of symbols]

 11 Insulating Substrate 12 Membrane Electrode 13 Lead Wire 14 Temperature Fuse Element 15 Flux 16 Membrane Electrode 17 Membrane Resistor 19 Lead Wire 1 Resistance / Temperature Fuse Main Body 2 Case 20 Bulging Part 21 Pre- Toe 22 Frame edge 3 Curable insulating material

Claims (5)

[Claims] 1. A resistance / temperature fuse main body comprising a thermal fuse insulating substrate and a temperature fuse element and two film resistors having different resistance values sandwiching the element, and a heat transfer adjusting case for the main body of the resistor / temperature fuse. -When the case is covered, the insulating material is injected and solidified in the case, and the operating time of the temperature fuse elements based on the heat generation of each film resistor under the same overcurrent is made substantially equal. Resistance and temperature fuse characterized by 2. A thermal fuse element is provided at the center of one surface of a heat conductive insulating substrate, and a film resistor having different resistance values symmetrically with respect to the temperature fuse element is provided on the other surface of the substrate. The resistance / temperature fuse
A heat transfer adjusting case having a frame edge around the outer periphery of the housing is applied with its plate disposed on the temperature fuse element side, and an insulating material is injected and solidified in the housing, It is characterized in that the plate portion of the case is left-right asymmetric so that the operating time of the temperature fuse element based on the heat generation of each film resistor under the same overcurrent is made substantially equal. resistance·
Temperature fuse. 3. The left and right portions of the plate portion of the case are close to one surface of the insulating substrate of the resistance / temperature fuse main body, and the temperature fuse element is accommodated in the remaining intermediate bulge portion. The resistance / temperature fuse according to claim 2. 4. A thermal fuse insulating substrate is provided with a temperature fuse element on one surface thereof, and two film resistors having different resistance values are provided on the other surface of the substrate with the temperature fuse element interposed therebetween. The resistance / temperature fuse main body is covered with a symmetrical heat transfer adjusting case, and an insulating material is injected and solidified in the case.
The distance between each film resistor and the temperature fuse element should be different so that the operating time of the temperature fuse element based on the heat generation of each film resistor under the same overcurrent is almost equal. Characteristic resistance and temperature fuse. 5. The left and right portions of the plate portion of the case are close to one surface of the insulating substrate of the resistance / temperature fuse main body, and the temperature fuse element is accommodated in the remaining intermediate bulging portion. The resistance / temperature fuse according to claim 4.