JP6426413B2 - Method of manufacturing sealed electric wire fuse - Google Patents

Description

  According to the present invention, the fuse element is housed in an insulating cylinder in which both end openings are sealed by the insulating cap, and both ends of the fuse element are connected to the inner end of the sleeve through which the insulating cap is inserted. In particular, the present invention relates to an improvement in the mounting structure of a sleeve in a sealed electric wire fuse in which lead wires are connected.

  For example, in Patent Document 1, a fuse tube having an inner and outer double fuse tube is provided, and a terminal metal fitting for wire connection is protruded from the outer tube both end opening through a sleeve and the both end opening is sealed with an outer cap A wire fuse is disclosed in which a fuse element is connected between these terminals in a cylinder.

  Further, also in Patent Document 2, an inner cap and an outer side thereof are covered with a protective cap at both ends of the insulating cylinder, and a terminal (sleeve) is disposed airtightly on the central line through the protective cap. A lead wire is connected to this terminal, and a wire fuse in which a fuse element provided with a low melting metal piece at the center is stretched between the terminals is disclosed.

  The configuration of connecting the fuse element and the lead wire through the sleeve is a technical means that is usually adopted in a sealed type wire fuse, but the sleeve passes through the insulating cap that seals both ends of the insulating cylinder and the outside of the insulating cylinder It is necessary to devise a device to maintain watertightness.

Here, the conventional attachment structure of the sleeve will be described.
FIG. 5 is an overall sectional view showing an example of a conventional sealed wire fuse.
In this sealed wire fuse, a sleeve 15 having a partition 15a at the axially intermediate portion is fixed to the resin insulating cap 14 for sealing the opening at both ends of the insulating cylinder 13 by connecting the inside and the outside of the insulating cylinder 13 The fuse element 16 is connected to the inner end portion of the sleeve 15 in 13, and the lead wire is connected to the outer end portion of the sleeve 15 led out to the outside of the insulating cap 14 The following measures were taken to ensure watertightness when taking out outside the

  First, as shown in FIG. 6 (B), a part in which the sleeve 15 subjected to header processing and the insulating inner cap 14a are integrated by insert molding is prepared, and as shown in FIG. 7 (A), the inner cap 14a is prepared. End faces of the cylinder and the insulating cylinder 13 are ultrasonically welded, the insulating outer cap 14b is covered from the inner cap 14a to the insulating cylinder 13, and the inner cap 14a and the outer cap 14b are integrated by ultrasonic welding .

  At this time, in order to improve the water tightness, silicon is applied to the gap between the inner cap 14a and the sleeve 15 as shown in FIG. 7B, and after leaving it to be cured, it is shown in FIG. As shown in FIG. 7E, the outer cap 14b is covered and the inside of the outer cap is filled with silicon, and then integrated by ultrasonic welding as shown in FIG. 7D. The silicon was again applied and cured as shown.

  According to such a sleeve attachment structure, the insert molding of the sleeve and the inner cap can not but be asked to a molding company, there is a disadvantage that processing cost and physical distribution cost are required, and the lead time at the time of product manufacture is prolonged. was there. Furthermore, according to insert molding, residual stress remains as it is, which causes distortion.

  In addition, the end faces of the inner cap 14a and the insulating cylinder 13 are ultrasonically welded, and the inner cap 14a and the outer cap 14b are ultrasonically welded, but ultrasonic welding is repeated a total of four times on the left and right of the insulating cylinder 13. However, there is also a problem that stress accumulation increases. Furthermore, when applying silicon, the silicon used in FIGS. 7B and 7E may be the same low-viscosity silicon, but the silicon used in FIG. 7C uses high-viscosity silicon. , Two types of silicon were required.

JP 2013-175362 Japanese Patent Application Laid-Open No. 7-182964

Therefore, an object of the present invention is to eliminate the inner cap integrated by the sleeve and the insert molding in a method of manufacturing a sealed electric wire fuse configured to connect the fuse element and the lead wire through the sleeve. In addition to reducing the number of parts and processing and distribution costs and shortening the lead time during product manufacture, the number of times of ultrasonic welding where residual stress is likely to be accumulated is kept to a minimum, and silicon application is also achieved. SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a sealed wire fuse according to an improved sleeve mounting structure in which the number of applications can be minimized with one kind of silicon.

In order to achieve the above object, in the present invention, a method of manufacturing a sealed electric wire fuse having a configuration in which the fuse element and the lead wire are connected via a sleeve, ie, fixed to an insulating cylinder and sealing both end openings of the insulating cylinder a resin insulating cap, the sleeve having a partition wall in the axially intermediate portion is fixed in communication with the inside and outside of the insulating cylinder, the fuse element is connected to the inner end of the sleeve in the insulating cylinder, they are led out to the insulating cap outside a method of manufacturing a sealed type electric wire fuse so as to connect the lead wires to the outer end of the sleeve, and which have a flange at the inner end outer periphery of the sleeve, the insulating cap, receiving the flange of the sleeve while have a stepped portion, a unitary structure covering a range extending end outer surface from the end face of the insulating cylinder, firstly, to insert the sleeve into the insulating cap Receiving a flange at the step portion, then fixing the sleeve and the insulating cap is caulked to excess thickness portion of the insulating cap in the end peripheral sleeve after heating and softening by infrared irradiation, then the insulation tube insulation cap by ultrasonic welding It is characterized in that it is a method of manufacturing a sealed type wire fuse fixed to the

  That is, instead of the insulating cap having a double structure of the inner cap and the outer cap as in the prior art, the inner cap and the outer cap are replaced with a single insulating cap, eliminating the need for insert molding of the sleeve and the inner cap In addition, the number of ultrasonic weldings is limited to a minimum of two.

  When a plurality of radial grooves are formed on the flange end surface of the inner end outer periphery of the sleeve, the sleeve and the insulation cap are fixed by caulking the excess thickness portion provided on the insulation cap after heating and softening by infrared irradiation. This is desirable because the detent effect of the sleeve can be obtained and the twisting performance is improved.

In the method of manufacturing a sealed wire fuse according to the present invention, as described above, the conventional double structure of the inner cap and the outer cap is eliminated and a sleeve having a flange at the outer periphery of the inner end is combined with the insulating cap The excess thickness provided on the insulating cap around the inner end of the sleeve is heated and softened by infrared irradiation and then crimped to fix the sleeve and the insulating cap, and the insulating cap is secured to the insulating cylinder by ultrasonic welding. There is no need to insert-mold the sleeve and inner cap by outsourcing, and it is possible to reduce the residual stress and improve the quality, reduce the number of parts, and reduce the processing cost and the distribution cost. The lead time could also be shortened.

Also, the end faces of the inner cap and the insulating cylinder are conventionally ultrasonically welded, but instead of ultrasonic welding at this stage, the sleeve and the insulation cap are fixed by caulking after heating / softening by infrared irradiation. Therefore, it also has the advantage that stress accumulation due to ultrasonic welding and the adverse effect on quality due to residual stress can be reduced as much as possible.
Further, while the number of times of application of silicon is three in the conventional structure, the number of times of application may be one, and the number of silicon used can be reduced from two to one in the prior art.

Sectional view showing a sealed type electric wire fuses that manufactured by the method according to the present invention Front view and right side view of the sleeve in the same sealed wire fuse Cross section of the insulation cap of the same sealed type wire fuse The parts assembly process in the manufacturing method of the same sealed type electric wire fuse is shown, (A) is a state before combining a sleeve and an insulation cap, (B) is a state combining both, (C) is a heating / softening state by infrared radiation. (D) is a state in which the sleeve and the insulation cap are integrated by caulking the extra thickness part of the insulation cap by pressing and compression with the punch of the tool, (E) is fixing the insulation cap and the insulation cylinder by ultrasonic welding The state of (F) shows the state of finish silicon application, respectively. Sectional view showing an example of a conventional sealed wire fuse In the component drawing used for the fuse, (A) shows an outer cap, (B) shows an inner cap and a sleeve integrated by insert molding, and (C) shows an insulating cylinder. The component assembly process in the same sealed type electric wire fuse is shown, (A) is a state where the inner cap integrated with the sleeve by insert molding is ultrasonically welded between the end faces, (B) is the inner cap and Apply silicon to the gap of the sleeve and allow it to cure. (C) Apply silicon again and cover the outer cap, fill the outer cap with silicon, (D) Apply ultrasonic weld The state in which the cap and the inner cap are integrated, (E) shows a state in which silicon is applied as a final finish and left to be cured.

First, the overall structure of a sealed wire fuse in an embodiment of a manufacturing method according to the present invention will be described according to FIG.

  The sealed electric wire fuse is formed by connecting a sleeve 4 having a partition 3 at an axially intermediate portion to an insulating cap 2 made of resin which seals openings at both ends of the insulating cylinder 1 by connecting the inside and outside of the insulating cylinder 1 The fuse element 5 is connected to the inner end of the sleeve 4 in 1 and the lead wire is connected to the outer end of the sleeve 4 led out to the outside of the insulating cap 2. Inside the glass tube 6 is disposed a rubber cap 7 at both ends.

  The fuse element 5 is composed of a fusible alloy 5a, a resistance wire 5b, and a connection terminal 5c, and has a supplementary pipe 5d for facilitating the heat transfer of the resistance wire 5b to the fusible alloy 5a. The connection between the sleeve 4 and the fuse element 5 is compression-connected by inserting the connection terminal 5 c into the sleeve 4. A sleeve cover 8 is covered from the sleeve 4 drawn out from the insulating cap 2 to the outer surface of the insulating cap 2.

A feature of this sealed wire fuse is the mounting structure of the sleeve.
In a conventional sealed electric wire fuse, a component in which a sleeve-processed sleeve and an insulating inner cap are integrated by insert molding is prepared, and the end faces of the inner cap and the insulating cylinder are ultrasonically welded to insulate them. Outer cap is covered from the inner cap to the insulating cylinder, and the inner cap and the outer cap are integrated by ultrasonic welding. In the present invention, the insulating cap has a double structure of the inner cap and the outer cap. Instead of using the inner cap and the outer cap as a single insulating cap, insert molding of the sleeve and the inner cap is not required, and the number of ultrasonic weldings is kept to a minimum.

  That is, the sleeve 4 having the flange 9 on the outer periphery of the inner end portion is combined with the insulating cap 2 received at the step portion 10, and the excess thickness portion 11 provided on the insulating cap 2 at the outer periphery of the inner end portion is crimped after heating and softening by infrared radiation. The sleeve 4 and the insulating cap 2 are fixed, and the insulating cap 2 is fixed to the insulating cylinder 1 by ultrasonic welding.

  The flange 9 of the sleeve 4 is processed into a header. At this time, if a plurality of radial grooves 9a are formed on the end face of the flange, the effect of preventing rotation of the sleeve is obtained, and the twisting performance is improved. Further, when the sleeve 4 and the insulating cap 2 are combined, if the axial dimension of the large diameter portion 9b at the lower part of the flange 9 is made substantially flush with the outer end face of the insulating cap 2, a bending load is applied to the sleeve It is desirable because the water tightness can be maintained even in the

The assembly process will be described according to FIG.
As shown in FIGS. 4A and 4B, the sleeve 4 and the insulating cap 2 are combined in the retaining state at the flange 9 and the step portion 10, and as shown in FIG. The excess thickness portion 11 provided on the cap 2 is heated and softened by infrared irradiation. Then, as shown in FIG. 4D, the excess thickness portion 11 of the insulating cap 2 is crimped by pressure and compression with a punch 12 of a tool to integrate the sleeve 4 and the insulating cap 2. After that, as shown in FIG. 4 (E), the insulating cap 2 and the insulating cylinder 1 are fixed by ultrasonic welding, and as shown in FIG. 4 (F), the finish silicon is applied and cured to complete the assembly. Do.

As described above, according to the method of manufacturing a sealed type wire fuse of the present invention, it is not necessary to insert-mold the sleeve and the inner cap by outsourcing, and the residual stress can be reduced to improve the quality. Cost and physical distribution costs can be reduced, and lead time at the time of product manufacture can be shortened, and the sleeve and the insulation cap are fixed by heating and softening due to infrared irradiation, so that the conventional method 7A has the advantage of eliminating the need for ultrasonic welding in FIG. 7A and minimizing the adverse effects of stress accumulation and residual stress on the quality. Furthermore, the number of times of application of silicon is reduced, and one type of silicon is used. It is possible to provide a method of manufacturing a sealed wire fuse which greatly reduces the productivity and quality.

DESCRIPTION OF SYMBOLS 1 insulation cylinder 2 insulation cap 3 partition 4 sleeve 5 fuse element 9 flange 10 step part 11 excess thickness part 9 a groove

Claims (2)

A resin insulating cap for sealing the openings of both ends of the insulating cylinder is secured to the insulating cylinder, the sleeve having a partition wall in the axially intermediate portion is fixed in communication with the inside and outside of the insulating cylinder, of the sleeve in the insulating cylinder In a method of manufacturing a sealed wire fuse in which a fuse element is connected to an end and a lead wire is connected to an outer end of a sleeve drawn out of an insulating cap.
Shall have a flange at the inner end outer periphery of the sleeve, the insulating caps, as well as have a stepped portion for receiving the flange of the sleeve, a unitary structure covering a range extending end outer surface from the end face of the insulating cylinder,
First, receiving the flange in the step portion by inserting the sleeve in the insulating cap, then caulked and fixed to an insulating cap sleeve Te an excess thickness portion of the insulating cap in the end peripheral sleeve after heating and softening by infrared irradiation, then A method of manufacturing a sealed wire fuse, wherein the insulating cap is fixed to the insulating cylinder by ultrasonic welding. The method of manufacturing a sealed wire fuse according to claim 1, wherein a plurality of radial grooves are formed on the flange end surface of the sleeve.

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