JP2704163B2 - Fuse resistor and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuse resistor that automatically shuts off current when an abnormal current flows in an electric circuit and the resistor is overloaded, and its manufacture. About the method.

[Related Art] In recent years, a large-sized display formed by arranging a large number of fluorescent tubes vertically and horizontally has been installed in a baseball field or the like. here,
When the life of the fluorescent tube expires, the degree of vacuum in the tube decreases and an excessive current flows in the circuit. Therefore, the circuit is interrupted by a breaker to protect the circuit.

A conventional fuse resistor is disclosed in Japanese Utility Model Laid-Open No. 57-197605, which uses a low melting point solder to function as a fuse, and is disclosed in JP-A-55-48902. As described above, there is a type in which a fuse acting body is attached to the surface of a film resistor, and this portion is cut when an abnormal load is applied by the fuse acting body.

[Problems to be Solved by the Invention] In the above-mentioned conventional display, even if only one fluorescent tube is gradually reduced in vacuum degree and short-circuited, the breaker of the entire display falls and the entire screen disappears. was there. Moreover, once the screen disappears, it is extremely difficult to find out where the fluorescent tube has been cut, and much time has been spent replacing the fluorescent tube. Therefore, it is conceivable to attach a fuse resistor to each fluorescent tube. However, if the above-described conventional fuse resistor is used for such a fluorescent tube, the variation in the power value at which the fuse blows is large, and the time until the fuse blows is long. There was a disadvantage that it was long, and it was not practical because it did not protect the circuit. Especially,
The one with the fuse acting will leak in this part under the condition where high voltage is applied even if it blows,
It cannot be used as a fuse for a fluorescent tube as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a fuse resistor that functions accurately even at a predetermined power value, especially a low power value, and that is instantaneously blown and easy to manufacture. The aim is to provide a method.

[Means for Solving the Problems] According to the present invention, a groove is formed in a circumferential direction on a side peripheral surface of a fixed resistor, one end is connected to one end of a spring, and the other end of the spring is connected to one electrode member. The fixed resistor and the spring are connected in series and inserted into the cover, the other end of the fixed resistor is connected to the other electrode member, and the pair of electrode members apply a certain force to the spring. The fuse resistors are respectively fixed to the cover or the substrate or the like in a state where tension is applied in a longitudinal direction of the fixed resistor.

Further, the present invention provides a resin-coated surface on a side peripheral surface of a fixed resistor to form a groove in a circumferential direction, and connects a spring to one end of the fixed resistor and the other end of the fixed resistor. Is connected to one electrode member, a drawing jig is hung on the other end of the spring, the fixed resistor and the spring are inserted into the cover along the drawing jig, and the drawing jig is connected to the other electrode member. And connecting the other end of the spring to the other electrode member and fixing the other end of the spring.

[Function] The fuse resistor according to the present invention is such that the fixed resistor itself is easily and surely broken by an abnormal current, and the pieces of the fixed resistor are largely separated from each other by the spring at the same time as the breakage. It is.

Further, the method of manufacturing a fuse resistor according to the present invention is such that a predetermined groove is accurately formed on the surface of the fixed resistor by laser light, and a spring and a fixed resistor are easily tensioned between a pair of electrode members. These can be fixed to the above.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 7 show a first embodiment of the present invention. The fuse resistor of this embodiment uses a fixed resistor 1 of a carbon-resin solid resistor, and has a side peripheral surface thereof. 100 in the circumferential direction for resin coating of
A groove 2 of about μ is formed. Here, the resin on the surface is a thermosetting resin. Terminals 3 and 4 provided at both ends of the fixed resistor 1 are bent into a U-shape and a U-shape, and the terminal 3 is provided with a locking portion 6 at one end of a metal coil spring 5.
Is engaged. Further, the locking portion 7 at the other end of the coil spring 5
Is formed in a U-shape, is inserted into the elongated hole 9 of the bottom surface of the cap-shaped electrode member 8, and the U-shaped tip is a small hole 10 of the electrode member.
Is inserted. Further, the terminal 4 of the fixed resistor 1 is inserted through the elongated hole 9 of the bottom surface of the other cap-shaped electrode member 8 in the same manner as described above, and the U-shaped tip is inserted through the small hole 10 of the electrode member 8. . The outer side of the bottom surface of each electrode member 8 is covered with the terminal 4 and the locking portion 7 by soldering or welding to form a smooth surface.

The fixed resistor 1 and the coil spring 5 are inserted into a transparent cylindrical glass cover 11, and a pair of cap-shaped electrode members 8 are attached so as to cover both ends of the cover 11, and the coil spring 5 is fixed. It is inserted into the cover 11 while being stretched by tension.

Next, a method of manufacturing the fuse resistor of this embodiment will be described with reference to FIG. First, as shown in FIG. 7A, a groove 2 is formed on the surface of the fixed resistor 1 by a YAG laser 20. The groove 2 is formed in a spiral shape by moving the fixed resistor 1 to one side while rotating.
Next, as shown in FIG. 7 (B), the terminals of the fixed resistor 1
Each of 3 and 4 is bent into a U-shape and a U-shape with predetermined jigs. Then, as shown in FIG. 7 (C), the engaging portion 6 of the coil spring 5 is engaged with the terminal 3, and this engaging portion is soldered. Thereafter, as shown in FIG. 7 (D), the terminal 4 is inserted into the elongated hole 9 of the electrode member 8 and rotated by 90 degrees to insert the U-shaped tip into the small hole 10. Then, soldering or welding is performed on the outer bottom surface of the electrode member 8 to smooth the terminal 4 so that the terminal 4 cannot be seen. Next, as shown in FIG. 7 (E), the hook portion 22 of the J-shaped drawing jig 21 is hooked on the engaging portion 7 of the coil spring 5, and the cover 11 is inserted through the drawing jig 21, and further drawn. Connect the end of the jig 21 to the other electrode member 8
Through the long hole 9. Then, the pulling jig 21 is pulled to insert the locking portion 7 into the elongated hole 9 of the electrode member 8, and is rotated 90 degrees to insert the U-shaped tip into the small hole 10. Finally, the outer bottom surface of the other electrode member 8 is also subjected to soldering or welding,
Smooth the locking part 7 so that it cannot be seen.

Here, the steps shown in FIGS. 7 (C) and 7 (D) may be reversed, and the soldering or the like of the outer bottom surface of the electrode member may be performed on both end surfaces last.

The fuse resistor of this embodiment normally functions as a normal resistor, and is attached to, for example, each fluorescent tube or a few fluorescent tubes of a large-screen display formed by arranging a large number of fluorescent tubes vertically and horizontally. Then, when the degree of vacuum of one of the fluorescent tubes of the display is gradually reduced and short-circuited, the fuse resistor connected thereto is blown to prevent an excessive voltage from being applied to the circuit.

When an excessive pressure is applied to the fuse resistor, the fixed resistor 1 breaks at a central portion of the groove 2, and one piece of the fixed resistor 1 is separated by the coil spring 5 as shown in FIG. It is drawn toward one electrode member 8. As a result, the intervals between the fragments of the fixed resistor 1 are widened so that no electric discharge occurs between them. The mechanism by which the fixed resistor 1 breaks is that when an excessive voltage is applied, the resistor is overheated and a difference in the coefficient of thermal expansion between the carbon and the resin coating causes the groove 2 at the center to be broken.
The stress concentration is generated in the fixed resistor 1, the crack is formed therein, the crack is broken, and the pieces of the fixed resistor 1 are separated from each other at a stretch by the tension of the coil spring 5. This rupture is likely to occur almost at the center of the fixed resistor 1 because the temperature is highest at the center.

According to the fuse resistor of this embodiment, the resistor 1 itself breaks at the groove 2 to cut off the circuit, and the coil springs 5 instantaneously separate the fragments from each other. And leakage of current due to discharge between the electrodes can be prevented. Then, even if one of the fluorescent tubes of the large-screen display is short-circuited, the fuse screen connected to the fluorescent tube is only cut and the entire screen is not erased.

Further, since the fixed resistor 1 of this embodiment is a solid resistor made of carbon, it is broken accurately at a relatively low voltage.

Further, in this embodiment, since the end surfaces of the electrode members 8 are covered with solder and the terminals 4 and the like are U-shaped and the tips are inserted into the inside of the electrode members, the terminals 4 and the like can be connected even if a high voltage is applied. There is no spark coming out of the tip.

Further, according to the method of manufacturing the fuse resistor of this embodiment, the thin groove 2 can be accurately formed in the small resistor by the laser beam. In addition, the coil spring 5 can be easily and reliably stretched.

Next, a second embodiment of the present invention will be described with reference to FIGS. Here, the same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the fuse resistor of this embodiment, electrode members 31 are fixed to both ends of a substrate 30 such as a ceramic or a synthetic resin.
As shown in FIG. 9, the electrode member 31 has a long hole 32 and a small hole 33, and the terminal 4 and the locking portion 7 are engaged in the same manner as in the above embodiment. Then, a terminal portion 34 extends from one end of the electrode member 31. Further, a box-shaped cover 35 is provided on the substrate 30,
The locking piece 36 is engaged with the substrate 30 and covered.

The fuse resistor of this embodiment has a terminal portion on a circuit board or the like.
34 is inserted and fixed. As a result, the device can be directly attached to the circuit board, space can be effectively used, and the device can be downsized.

The fixed resistor used in the fuse resistor of the present invention may have one groove 2 formed in a ring shape or a plurality of grooves as shown in FIG. Also,
It goes without saying that a carbon film resistor, a metal film resistor, a metal glaze resistor, and the like, other than the solid resistor, can be appropriately selected and used according to the voltage value and the application.

Further, the spring used in the present invention may be a spring in which a spiral spring or a leaf spring is bent in addition to the coil spring, and may be a spring that applies tension in the longitudinal direction of the fixed resistor. The position of the fixed resistor may be between the springs, or may be mounted on both sides of the spring.

Further, the cover may be made of plastic or the like other than glass, and may not be transparent.

[Effects of the Invention] The fuse resistor of the present invention pulls the fixed resistor in the longitudinal direction with a spring, so that the fixed resistor itself breaks when excessive power is applied. Can be shut off. In addition, since the groove is formed on the peripheral surface of the fixed resistor, the fixed resistor is broken very accurately with a predetermined power. The fixed resistor and spring are
Since it is covered with the cover, the fragments are not scattered even when broken, and the safety is high.

Further, since the electrodes are locked or fixed near both ends of the cover, it can be easily replaced like a normal fuse.

Further, in the method of manufacturing a fuse resistor according to the present invention, since the groove is formed by the laser beam, a narrow groove can be accurately formed in a small resistor. Further, since the spring is pulled to the electrode member by the pulling jig, the spring can be easily fixed to the electrode member.

[Brief description of the drawings]

1 is a sectional view of a first embodiment of a fuse resistor according to the present invention, FIG. 2 is a front view of a fixed resistor of this embodiment, FIG. 3 is a front view of an electrode member of this embodiment, FIG. The figure is A in FIG.
FIG. 5 is a front view of the fixed resistor of this embodiment in a state where the terminals of the fixed resistor are bent, FIG. 6 is a cross-sectional view of the fixed resistor of this embodiment in a state where the fuse resistor is cut, and FIG. ) Or (E)
FIG. 8 is a process diagram showing a method for manufacturing the fuse resistor of this embodiment, FIG. 8 is a sectional view of a second embodiment of the fixed resistor of the present invention, FIG. 9 is a front view of an electrode member of the second embodiment, FIG. 10 is a front view showing an embodiment of a groove formed in the fixed resistor according to the present invention. 1 ... fixed resistor, 2 ... groove, 3, 4 ... terminal, 5 ... coil spring, 6, 7 ... locking part, 8,31 ... electrode member, 9, 32 ... ... elongated hole, 10 , 33 …… Small hole, 11,35 …… Cover, 21 …… Drawing jig

Claims (5)

(57) [Claims] A groove is formed in a circumferential direction in a resin coating on a side peripheral surface of a fixed resistor, and one end of a spring is connected to one end of the fixed resistor, and the other end of the spring is connected to one electrode. Connected to the member, the fixed resistor is connected in series with the spring in the longitudinal direction thereof and inserted into the cover, the other end of the fixed resistor is connected to the other electrode member, and a pair of electrode members A fuse resistor fixed in a state in which a fixed force is applied to a spring to apply tension in a longitudinal direction of the fixed resistor. 2. The fixed resistor is a solid resistor made of a carbon rod. One of terminals at both ends is connected in series to a coil spring made of metal, and the other terminal is soldered to one electrode member. The fixed resistor and the coil spring are inserted into the cylindrical cover, and the other end of the coil spring is soldered to the other electrode member, and the pair of electrode members apply a fixed force to the spring to fix the fixed resistor. 2. A fuse resistor according to claim 1, wherein said fuse resistor is engaged with both ends of said cover while tension is applied in a longitudinal direction of said fuse. 3. The fuse resistor according to claim 1, wherein said pair of electrode members are fixed to an insulating substrate, and said cover is attached to said substrate by covering a fixed resistor and a coil spring. vessel. 4. A step of irradiating the resin coating on the side peripheral surface of the fixed resistor with a laser beam to form a groove in the circumferential direction, and connecting a spring to one end of the fixed resistor and the other end of the fixed resistor. A step of connecting a pulling jig to the other end of the spring, a step of inserting the fixed resistor and the spring through the cover along the drawing jig, and further including the drawing jig. Pulling in the direction of the other electrode member to apply tension to the spring, and connecting and fixing the other end of the spring to the other electrode member. 5. The pulling jig has a hook portion engageable with a locking portion at the other end of the spring, and the hook portion is passed through an elongated hole formed in the electrode member to allow the spring member to receive the spring. The spring is drawn to the electrode member by engaging with the locking portion and pulling the pulling jig, and the locking portion of the spring is engaged with a long hole to a small hole of the electrode member. Item 5. A method for manufacturing a fuse resistor according to Item 4.