JPH0456412B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention detects an abnormality such as excessive temperature rise during use of industrial equipment and household electrical appliances, and interrupts the electric circuit to prevent equipment damage accidents. , relates to the manufacture of cases used in temperature fuses for the prevention of fire. [Prior art] The configuration of a conventional temperature fuse is shown in Figures 5 and 6.
As shown in the figure, reference numeral 1 denotes a case, which has a U-shaped cylinder shape with an opening on the input side and a bottom surface on the output side. A temperature-sensitive pellet 2 is housed on the output side of the case 1, and an insulating bushing 3 is housed on the input side. Further, a lead terminal 4 is crimped to the bottom surface of the case 1, and a lead terminal 5 is inserted inward through an insulating bushing 3 from the opening, and the opening is sealed with a sealing resin 6. It's blocked. Furthermore, a strong compression spring 10 held between the pressure plates 8 and 9 on the output side and a weak compression spring 11 on the input side are interposed between the temperature-sensitive pellet 2 and the insulating bushing 3. is housed so as to be in contact with a fixed contact 12 provided at the tip of the lead terminal 5. Conventionally, in the case of this type of temperature fuse, as shown in FIG. As shown in FIGS. 4B and D, a second lower mold 35 and a second upper mold 36 are attached to the plate material 31.
The hollow hole 37 is formed by drawing, and then the first pin 38 is inserted into the bottom surface of the hollow hole 37 to form a through hole 39, and the case 1 having a predetermined shape is formed by drawing. . [Problems to be Solved by the Invention] However, in the case of the press-formed case 1, the degree of processing deformation of the case 1, that is, the wall thickness (hereinafter referred to as wall thickness) is not constant and uneven when the case 1 is drawn. This caused a difference in hardness depending on the part of the case 1 due to the unevenness. This is clear from the following findings as a result of experiments. That is, the through hole 39 of case 1
The hardness around the opening of the case 1 was Hv91, and the hardness around the opening of the case 1 was Hv122.As a result, the hardness around the through hole 30, which is the part where the lead terminal 4 is caulked and fixed, was lower than other parts. In addition, since the press working method is used, the surface roughness of the inner circumferential surface of case 1 decreases, causing roughness on the inner circumferential surface of case 1. The movable contact piece 7 may get caught and movement of the movable contact piece 7 may be blocked, causing problems such as a decrease in the operating accuracy of the temperature fuse. [Means for Solving the Problems] The present invention was invented for the purpose of solving these problems and providing a product with stable performance. 14, the second die 16, the first punch 15, and the second punch 17 cut the material 1 made of a wire rod.
A blank 18 is manufactured by pressing the ends of both sides of the blank 18, and then a recessed hole 22 having a diameter slightly larger than the hollow hole 21 described later is formed on the front end surface of the blank 18 using a third die 19 and a first pin 23. And furthermore, the fourth
A hollow hole 21 is formed from the bottom of the recessed hole 22 using a die 24 and a second pin 26, and finally a through hole 30 is formed at the bottom of the hollow hole 21 using a fifth die 27 and a third pin 29. be. [Function] In the case 1 which has been forged in this way, the wall thickness becomes uniform when the case 1 is formed, and there is no difference in hardness depending on the parts of the case 1. This is clear from the following findings as a result of experiments. That is, the hardness around the through hole 30 of case 1 is Hv128, and the hardness around the opening of case 1 is Hv129, and as a result, the hardness of the caulked and fixed portion of the lead terminal 4 is almost equal to the hardness around the opening. . In addition, since the forging method is adopted, the surface roughness of the inner circumferential surface of the case 1 is improved, the inner circumferential surface of the case 1 is free from roughness, and the movable contact piece 7 of the case 1 when the temperature fuse is operated is The inner peripheral surface of the fuse can now be moved easily, improving the operating accuracy of the temperature fuse. [Examples] Examples of the present invention will be described below based on the drawings.
In FIGS. 2 and 3, reference numeral 1 denotes a case, which has a U-shaped cylinder shape with an opening on the input side and a bottom surface on the output side. A temperature-sensitive pellet 2 is housed on the output side of the case 1, and an insulating bushing 3 is housed on the input side. Further, a lead terminal 4 is crimped on the bottom surface of the case 1, while a lead terminal 5 is inserted from the opening.
is inserted into the insulating bushing 3 inwardly,
The opening is closed with sealing resin 6.
Furthermore, a strong compression spring 10 held between the pressure plates 8 and 9 on the output side and a weak compression spring 11 on the input side are interposed between the temperature-sensitive pellet 2 and the insulating bushing 3. is housed so as to be in contact with a fixed contact 12 provided at the tip of the lead terminal 5. The normal current path of the temperature fuse configured as described above is as shown in FIG.
The input side is as follows. Lead terminal 5 → Movable contact piece 7 → Case 1 → Lead terminal 4 The current connection between lead terminal 5 and case 1 is as follows:
The movable contact piece 7 is pressed against the fixed contact 12 of the lead terminal 5 by the pressure of the strong compression spring 10, and
This is achieved by the outer edge of the movable contact piece 7 always being in contact with the inner surface of the case 1 under the action of a spring. On the other hand, the current path in the event of an abnormality is as shown in FIG. 3. When the temperature reaches the rated temperature, the temperature-sensitive pellet 2 melts, the strong compression spring 10 is released, and the weak compression spring 11 that was maintaining equilibrium is thereby is released, the movable contact piece 7 moves toward the strong compression spring 10, and as a result,
The lead terminal 5 is no longer in contact with the fixed contact 12, and the electrical path with the case 1 is cut off. Next, a method of manufacturing the case 1, which is the main part of the present invention, will be explained. In a multi-stage heading machine, the wire rod is cut into predetermined dimensions as shown in Fig. 1A, and
As shown in FIG. 1C, the cut material 13 obtained by cutting the wire into a predetermined size is pushed into the first die 14 by the first punch 15, and at the same time, the front end surface of the cut material 13 is pressed. , the cut material 13 is reversed, and the cut material 13 is again pushed into the second die 16 with the second punch 17, and at the same time, the rear end surface of the cut material 13 is pressed and surface pressed to form a blank 18. Manufacture. Next, as shown in FIG. 1D, the blank 1
8 into the third die 19 using the first sleeve 20, at the same time, a recessed hole 22 having a slightly larger diameter than the hollow hole 21 described later is formed in the front end surface of the blank 18 using the first pin 23, As shown in FIG. As shown, the blank 18 is passed through the fifth die 27 into the third sleeve 2.
At the same time, the third pin 29 is inserted into the bottom surface of the hollow hole 21 in the blank 18 to form a through hole 30 in the bottom surface of the hollow hole 21.
Complete Case 1 as shown in . In the case 1 that was forged as described above, the wall thickness became uniform when the case 1 was formed, and there was no difference in hardness depending on the parts of the case 1. This is clear from the following findings as a result of experiments. That is, the through hole 23 of the case 1
The hardness around the opening of the case 1 was Hv128, and the hardness around the opening of the case 1 was Hv129.As a result, the hardness of the caulked and fixed portion of the lead terminal 4 became almost uniform with the hardness around the opening. In addition, since the forging method is adopted, the surface roughness of the inner circumferential surface of the case 1 is improved, the inner circumferential surface of the case 1 is free from roughness, and the movable contact piece 7 of the case 1 when the temperature fuse is operated is The inner peripheral surface of the fuse can now be moved easily, improving the operating accuracy of the temperature fuse. [Effects of the Invention] As explained above, the present invention provides a multi-stage heading machine that presses both ends of a cut material made of a wire rod by a first die, a second die, a first punch, and a second punch. A blank is manufactured, and then a recessed hole having a diameter slightly larger than the hollow hole described later is formed on the front end surface of the blank using a third die and a first pin, and a recessed hole having a diameter slightly larger than the hollow hole described later is formed on the bottom surface of the recessed hole using a fourth die and a second pin. A hollow hole is formed, and finally, a through hole is formed in the bottom of the hollow hole using a fifth die and a third pin, so in a case that is forged, the wall thickness will be uniform when the case is formed. There is no longer a difference in hardness depending on the part of the case. This is clear from the following findings as a result of experiments. That is, the hardness around the through hole 30 of the case was Hv128, and the hardness around the opening of the case was Hv129, and as a result, the hardness of the caulked and fixed portion of the lead terminal became almost uniform with the hardness around the opening. In addition, because the forging method is adopted, the surface roughness of the inner circumferential surface of the case is improved, and there is no roughness on the inner circumferential surface of the case, and the movable contact piece when operating the temperature fuse is The temperature fuse can now be moved more easily, improving the accuracy of the temperature fuse operation. As a result, it is possible to mass-produce cases with stable performance.

[Brief explanation of the drawing]

FIGS. 1A, B, C, D, E, F, and G are process diagrams showing a method of manufacturing a temperature fuse case according to the present invention, and FIG. 2 is a cross-sectional view of the temperature fuse according to the present invention, FIG. 3 is a sectional view showing the state after the operation of FIG. 2, FIGS. 4A and B are process diagrams showing a conventional method of manufacturing a temperature fuse case, and FIGS. 4C and D are , FIG. 4 is a top view of FIGS. 4A and 4B, FIG. 5 is a sectional view of a conventional thermal fuse, and FIG. 6 is a sectional view showing the state after operation of FIG. 5. 1... Case, 2... Temperature-sensitive pellet, 3... Insulating bushing, 4... Lead terminal, 5... Lead terminal, 6...
Sealing resin, 7... Movable contact piece, 8, 9... Pressing plate, 10
... Strong compression spring, 11... Weak compression spring, 12... Fixed contact, 13... Cutting material, 14... First die, 15...
1st punch, 16...2nd die, 17...2nd punch, 18...blank, 19...3rd die, 20...
First sleeve, 21...Hollow hole, 22...Concave hole, 23
...First pin, 24...Fourth die, 25...Second sleeve, 26...Second pin, 27...Fifth die, 28
...Third sleeve, 29...Third pin, 30...Through hole, 31...Plate material, 32...First lower die, 33...First upper die, 34...Concave hole, 35...Second lower die, 36...Second Upper mold, 37...Hollow hole, 38...First pin, 39...Through hole.

Claims (1)

[Scope of Claims] 1 In a multi-stage heading machine, a wire rod is cut into a predetermined size, and a cut material 1 obtained by cutting the wire rod into a predetermined size.
3 into the first die 14 with the first punch 15, and at the same time presses the front end surface of the cut material 13.Furthermore, the cut material 13 is reversed, and the cut material 13 is pushed into the second die 16 again. At the same time as pressing with two punches 17, the rear end surface of the cut material 13 is pressed and surface pressed to produce a blank 18, and then the blank 18 is pushed into a third die 19 with a first sleeve 20. At the same time, a recessed hole 22 having a diameter slightly larger than the hollow hole 21 described later is formed in the front end surface of the blank 18 using the first pin 23, and at the same time, the blank 18 is pushed into the fourth die 24 using the second sleeve 25. , a hollow hole 21 is formed from the bottom surface of the blank 18 by a second pin 26, and finally, the blank 18 is pushed into the fifth die 27 by a third sleeve 28, and at the same time, a third hole 21 is formed from the bottom surface of the hollow hole 21 in the blank 18. A method for manufacturing a case for a temperature fuse, characterized in that a through hole 30 is formed at the bottom of a hollow hole 21 through which a pin 29 is inserted.