JPH07296713A - Chip type fuse holder - Google Patents

Abstract

PURPOSE:To make inserting and pulling out of a fuse having a base board lead wire easy by selecting a chip type fuse holder having a special structure. CONSTITUTION:A chip type fuse holder is selected, wherein a base seat 3 made of a heat-proof insulated body having an U-shaped penetrating hole 3a and a groove 3b structured by forming by which a part of the end wall in an outer direction is exposed outward is provided on both ends of a rectangular parallelpiped form, a cubic terminal metal fitting 2 internally having a small hole 2a with its specified diameter and depth in a central part fittable into the penetrating hole 3a of the base seat 3 and a drilled hole 2b having its diameter and depth larger than this is provided, and further an excellent conductive body elastic metal thin plate is punched in the drilled hole 2b of the terminal metal fitting 2 and then round-processed in a bottle form, a contact spring 1 having a contact sandwiching part G surrounded by tip narrow parts 1a, 1b and 1c and the outer diameter of a columnar part 1d on a rear end is pressure-inserted into the diameter of the drilled hole 2b of the terminal metal fitting 2 from the outer diameter of the columnar part 1d through the tip and further, the terminal metal fitting 2 is pressure-inserted into the U shaped penetrating hole 3a on both ends of the base seat 3, fitted and fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type fuse holder mounted on a conductive land on a printed circuit board which does not have a through hole, and is mainly used to directly connect a lead wire of a fuse with a lead wire (including a microminiature type). The present invention relates to a chip type fuse holder that can be mounted from the surface without soldering to a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, for mounting a small-sized fuse with a lead wire for mounting on a board, a tip of a lead wire bent into an L shape is inserted into a through hole previously formed on the board.
It is a so-called through-hole mounting method in which it is soldered and fixed on the conductive pattern on the back side, and fuses may be replaced due to fusing on the board. At present, the fuse blown from the through hole is removed with a soldering iron, and a new non-defective fuse is reattached by soldering, and the fuse with the lead wire for the board can be attached with one touch without soldering. There was no disclosure of a fuse holder dedicated to a substrate as a means.

[0003]

Therefore, since the general method for mounting the above-mentioned fuse with lead wire to the substrate is to solder the back surface of the through hole of the substrate, the fixing method will be described below. Had some problems like: (B) Since the lead wire of the fuse is fixed by soldering from the back side of the board during installation, the fuse wire stretched inside the fuse with lead wire is affected by the heating of the soldering iron and the performance is improved. However, some of them are prone to deterioration. Therefore, it is necessary to manage the regulations (for example, the temperature of the soldering iron, the heating time, etc.) in mounting and manufacturing, which is extremely troublesome in terms of work. (B) When a disconnection occurs on the board, the solder must be removed or new soldering must be performed to replace it, which is very time-consuming and urgent. (C) Since the fuse itself becomes a heating element, it is necessary to clearly specify the distance from the substrate in consideration of the heat radiation state according to the magnitude of the rated current value. (D) Since the main body of the board-attached fuse with the board and the board are mounted with a gap so as not to be in close contact with each other, mechanical stress such as vibration and shock is easily applied, and the lead wire is easily deformed or broken. (E) After being mounted on the board, it is often placed together with resistors and other heat-generating components within a limited range due to high-density mounting, which causes the temperature rise of the board body and the conductive pattern. The temperature of conductive heat is apt to be increased, and the performance of the fuse is deteriorated and the life is shortened. (F) The current capacity of the conductive pattern of the substrate is 5A in terms of capacity.
Since the maximum is the maximum, it is disadvantageous in terms of circuit design because it is necessary to consider means for increasing the number of conductive patterns (for example, addition of spacers having conductive patterns) when a current larger than this is applied.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to round the bottle into a bottle shape in advance and to form a constricted portion at the tip of the contact holding portion. The contact spring is pressed into a cubical terminal fitting with a small hole and a counterbore in the center, and this terminal fitting is fitted into the U-shaped through holes at both ends of the pedestal made of heat-resistant insulation by press fitting. After forming a fixed chip-type fuse holder and placing it on the land of the board, fix it with cream solder to a part of the exposed part of the side surface of this terminal fitting, and with a single touch the lead wire fuse for the board. (EN) Provided is a surface mount chip type fuse holder which can be freely inserted and removed.

[0005]

In order to achieve the above object, the chip-type fuse holder of the present invention partially exposes a U-shaped through hole 3a and an outer edge wall at both ends of a rectangular parallelepiped shape. A pedestal 3 made of a heat-resistant insulating molded body having a groove 3b formed as described above, and a small hole having a predetermined diameter D ₁ and depth L ₁ in the central portion, which can be fitted into the through hole 3a of the pedestal 3. 2a and a cubic shaped terminal fitting 2 having a counterbore 2b having a diameter D ₂ and a depth L ₂ larger than the opening 2a therein, and further, after punching a good conductor elastic metal thin plate into the counterbore 2b of the terminal fitting 2, The contact spring 1 is rounded into a bottle shape and has the contact gripping portion G surrounded by the constricted portions 1a, 1b, 1c at the tip and the outer diameter D ₃ of the columnar portion 1d at the rear end and the total height L _3. from the tip to the diameter D ₂ of the probing hole 2b of the terminal fitting 2 the rear end of the The outer diameter D ₃ of the columnar portion 1d is press-fitted, and the terminal fitting 2 is further press-fitted into the U-shaped through holes 3a at both ends of the pedestal 3 so as to be fixed.

[0006]

[Function] Since the terminal fittings that are fitted and press-fitted into the U-shaped through holes at both ends of the pedestal are partially exposed on their side surfaces, this portion and the conductive pattern of the board are removed from the board surface by cream solder. Since they can be fixed together, it is not necessary to prepare a separate soldering terminal.

By using the chip type fuse holder, since the fuse wire does not conduct heat from a soldering iron or the like at all, a fuse with a lead wire for a substrate is used, which has the performance and characteristics of the manufactured state. it can.

Since all of the assembling steps are press-fitting methods, there is no need to perform machining and bonding, and therefore the manufacturing process is easy.

The contact spring that is press-fitted into the countersink hole in the terminal metal fitting must be adjusted to the portion of the bottle shape corresponding to the wire diameter (0.5 to 1.2 mm in diameter) of the lead wire of the board lead wire-attached fuse. Since it is easy, the wire diameters of various lead wires can be reliably clamped, and a constant insertion / removal force can always be obtained.

The contact sandwiching portion of the space surrounded by the constriction at the tip of the contact spring is formed by stamping out a good conductor elastic metal thin plate and setting its outer diameter to D ₃ , which has the outer diameter D ₂ of the terminal fitting. Since the lead wire is press-fitted into the counterbore hole, the lead wire can be securely clamped and contacted by the elastic resistance of only the elastic metal thin plate according to the wire diameter of the lead wire, so that stable electrical contact can be obtained.

[0011]

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a chip-type fuse holder according to an embodiment of the present invention. The contact spring 1 is formed by stamping out a good conductor elastic metal thin plate such as phosphor bronze for spring or beryllium copper (not shown). And rounded into a bottle shape,
The space G surrounded by the constricted portions 1a, 1b, 1c at three points at the tip is used as a contact holding portion, and the outer diameter D of the cylindrical portion 1d at the rear end is used.
₃ and an overall height L ₃ . The terminal fitting 2 is made of a good conductor such as brass or copper and has a cubic shape. A small hole 2a having a predetermined diameter D ₁ and a depth L ₁ at the center of the upper surface and a larger diameter D ₂ and depth L 1 are provided. Counterbore ₂ with 2
b is opened. The pedestal 3 is a molded body made of a heat-resistant insulating material such as a ferrule resin or a urea resin, and its shape is a rectangular parallelepiped. Groove 3b that is partially exposed
To have. Then, the following conditions should be fitted into the counterbore 2b of the terminal fitting 2 and the contact spring 1, that is, the diameter D ₂ (depth L ₂ ) of the counterbore 2b and the outer diameter of the cylindrical portion 1d of the contact spring 1. D ₃ (height L ₃ ) is D ₂ <D ₃ , (L ₂ >).
L ₃ ), so that it can be press-fitted and fixed.

FIG. 2 is a perspective view of a finished product of the chip type fuse holder of the present invention. In this figure, the terminal fitting 2 into which the contact spring 1 is press-fitted has a cubic shape, so that it is a pedestal. The U-shaped through-hole 3a of 3 can be press-fitted into the through-hole 3a from any of the upper and lower sides to be fitted and fixed. Further, at the time of press-fitting, smooth press-fitting and fixing can be obtained by the elastic effect generated in the gap between the U-shaped through holes 3a at both ends of the pedestal 3 and the groove 3b provided so as to partially expose the outer edge wall.
Moreover, since the assembly process is simple, it is easily manufactured and the workability and productivity are extremely good.

FIG. 3 is a sectional view taken along the line XX 'of FIG. 2, in which the terminal fittings 2 and the terminal fittings 2 press-fitted into the U-shaped through holes 3a at both ends of the pedestal 3 are shown. Since the inner contact spring 1 is positioned at a predetermined mounting interval, the lead wire F _{1 of the} fuse F with a lead wire for a substrate is aligned with this.
All you have to do is to form, insert and remove. Further, the contact holding portion G surrounded by the constricted portions 1a, 1b, 1c at the tip of the contact spring 1 has a lead wire F of the fuse F with a board lead wire.
_When the wire diameter G _{1 of No. 1} is inserted, the counterbore hole 2b of the terminal fitting 2
The contact is maintained in the sandwiched state due to the elastic sandwiching effect of the round metal of the thin sheet metal, and the cylindrical portion 1d at the rear end is engaged with the inner wall of the counterbore hole 2b by the elastic force to expand outward. Because it is stopped, it has a structure that does not move or slip out. Further, since the pedestal 3, the terminal fitting 2 and the contact spring 1 are respectively fixed by press-fitting and no mechanical joining or a method using an adhesive is used, the assembling process becomes extremely simple.

FIG. 4 is an explanatory view showing a state in which the chip-type fuse holder of the present invention is attached to a printed circuit board. The chip-type fuse holder mounted on the conductive land R of the printed circuit board P has its left and right terminals. The cream solder 10 is pre-applied to the side surface of the terminal fitting 2 which is in contact with the surface of the through hole 3a having a character shape and the groove 3b formed so as to partially expose the outer edge wall, and the soldering iron or the like heats up. The board conductive land R
Can be easily fixed by joining.

[0015]

As described above, since the chip type fuse holder of the present invention is used by being directly soldered and fixed to the land on the printed circuit board, it has the following effects and is industrially useful. Is. (B) Since there is no direct heating of the fuse with the lead wire for the substrate to be attached to the fuse wire, there is no influence on the performance at all, and it can be used for a long period of time. (B) Since it is easy to insert and remove the fuse with lead wire for the substrate, it is urgent to melt the fuse suddenly. (C) Since the pedestal has a large thickness, the fuse body to be mounted is fixed in a state of being lifted from the board by the thickness of the pedestal. This acts as a kind of heat dissipation spacer and suppresses the thermal influence conducted from the board to an extremely low level. It (D) Since the pedestal also functions as a spacer for fixing the main body of the board-use lead wire fuse, it is possible to absorb mechanical stress such as vibration and shock, so that disconnection is also prevented. (E) Since the terminal metal fittings and the contact springs have no electrical problem even if a current of about 10 amperes of the fuse with lead wire is applied, judging from the conductor capacitance, contact resistance, etc., the rated current is 10 It is possible to manufacture more than ampere. (F) Since a fuse with a lead wire using a glass tube can be used, the inside can be seen through, which is extremely convenient for a substrate that needs to be inspected for the presence or absence of disconnection of the fusible element and the fusing condition. (G) By pre-applying the adhesive 20 to the central portion of the back surface of the pedestal, the terminal metal fittings can be temporarily fixed while being placed between the conductive lands on the board, so that self-soldering by cream soldering is facilitated and large-scale mass production is possible. Can be measured.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a chip fuse holder of the present invention.

FIG. 2 is a perspective view showing a finished product of the chip type fuse holder of the present invention.

3 is a sectional view taken along line XX ′ in FIG.

FIG. 4 is an explanatory diagram of how the chip fuse holder of the present invention is mounted on a substrate.

[Explanation of symbols]

 1 Contact Spring 2 Terminal Metal 3 Pedestal 10 Cream Solder 20 Adhesive F Fuse with Lead Wire for PCB P Printed Circuit Board R Conductive Land

Claims (1)

[Claims] 1. A pedestal 3 made of a heat-resistant insulating molding having a U-shaped through hole 3a at both ends of a rectangular parallelepiped and a groove 3b formed so as to partially expose an outer edge wall, and this pedestal 3. A predetermined diameter D _{1 is provided at the} center part so that it can be fitted into the through hole 3a.
And a small hole 2a having a depth L ₁ and a larger diameter D ₂
DOO depth L explores hole 2b of the post counterbored hole 2b in good conductor elastic metal thin plate shape vent internal Furthermore the terminal fitting 2 of apertures the cubic shape to the terminal fitting 2 with _2, and rounding processing in liquor bottle shape, the tip A contact spring 1 having a contact pinching portion G surrounded by the constricted portions 1a, 1b, 1c, an outer diameter D ₃ of the cylindrical portion 1d at the rear end, and an overall height L ₃ is formed in the counterbore 2 of the terminal fitting 2.
The outer diameter D of the cylindrical portion 1d at the rear end from the front end of the diameter D ₂ of b
_3. A chip type fuse holder characterized in that ₃ is press-fitted, and the terminal fitting 2 is press-fitted into the U-shaped through holes 3a at both ends of the pedestal 3.