Vertical fuse

Abstract

An upper end cap and a lower end cap are installed at the upper end and the lower end of a vertical tube body respectively, the upper end cap comprises a cap body connected to the upper end of the tube body in a sleeving mode, a connecting piece is integrally formed on the cap body and supported on the outer side of the tube body, and flat pins used for being connected and welded to a PCB in an inserted mode are arranged at the bottom of the connecting piece. The pins are provided with at least one protruding part, and when the pins are inserted into the insertion holes in the PCB, interference fit is achieved through the protruding parts and the insertion holes. According to the utility model, the structure is simple, the heat dissipation capability is good, and the fuse can be stably welded on the PCB in a standing manner.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, and more specifically to a vertical fuse structure. Background Technology

[0002] A fuse is an electrical device that breaks the circuit by melting its fusible element when the current exceeds a specified value, thus protecting the circuit. Due to limitations, to save installation space on a PCB, fuses are often installed vertically, using fuses designed for vertical mounting. However, existing vertical fuses have the following disadvantages:

[0003] 1. In a vertical fuse, the fuse also includes end caps (usually copper caps) fixed at both ends of an insulating tube. The fusible element is placed in an insulating container, with both ends of the fusible element fixed to the end caps. During installation, the insulating tube is arranged vertically, with the end caps forming an upper cap and a lower cap respectively. The lower cap is connected to the PCB board, and then riveted to the upper cap via a tail wire. The tail wire extends upward from the top of the upper cap, bends to form an inverted U-shaped lead, and then extends vertically downward to the PCB board. In the above structure, because the bend of the tail wire is close to the riveting point, the riveting point is very easy to loosen.

[0004] 2. In the above-mentioned vertical fuse, since the tail wire is connected to the fuse by riveting, the diameter of the tail wire is limited by the riveting point. When the current specification of the fuse is large, the diameter of the tail wire cannot be increased, resulting in insufficient heat dissipation area of ​​the tail wire. This causes the highest temperature of the fuse to accumulate at the upper cap position. The solder inside the upper cap is prone to forming an M-effect point with the fusible element, causing the fuse to melt prematurely.

[0005] 3. Because the fuse is installed vertically, its horizontal width is relatively narrow. For example, the tail wire in the vertical fuse mentioned above has a small contact area between its bottom end and the PCB board, making it difficult to stand firmly on the PCB board and affecting the stability of the soldering.

[0006] 4. In order to ensure that the fuse can be stably soldered onto the PCB board, the existing vertical fuses are equipped with a base. The vertical fuse needs to be connected to the base and then placed on the PCB board. However, setting up the base not only increases the production cost, but also makes the structure of the vertical fuse more complicated. Utility Model Content

[0007] The purpose of this utility model is to provide a vertical fuse, which has a simple structure, good heat dissipation capacity, and can make the fuse stand firmly and be soldered on the PCB board.

[0008] To achieve the above objectives, the solution of this utility model is:

[0009] A vertical fuse includes an upper cap and a lower cap installed at the upper and lower ends of a vertical tube. The upper cap includes a cap body fitted onto the upper end of the tube body. A connecting piece is integrally formed on the cap body and supports the outside of the tube body. The bottom of the connecting piece is provided with a flat pin for insertion and soldering onto a PCB board. The pin is provided with at least one protrusion. When the pin is inserted into a socket on the PCB board, an interference fit is achieved between the protrusion and the socket.

[0010] Furthermore, the connecting piece includes a transverse piece extending outward from the outer wall of the cap body, the outer end of the transverse piece extending vertically downward to form an upright support piece, and the pins located at the bottom of the support piece.

[0011] Furthermore, the horizontal plate extends horizontally outward from the outer wall of the cap body by a certain distance, and the support plate is parallel to the outside of the vertical tube body, and the length of the support plate corresponds to the pin being able to be inserted into the plug hole.

[0012] Furthermore, both the transverse sheet and the support sheet are flat sheets with width.

[0013] Furthermore, the width of the pins is smaller than the width of the support plate.

[0014] Furthermore, the protrusion is located on the side wall of the pin, and the protrusion is a long strip-shaped ridge.

[0015] Furthermore, the surface of the protrusion abuts against the inner wall of the insertion hole.

[0016] Furthermore, the cap body of the upper end and the cap of the lower end are respectively fitted onto the two ends of the tube body by an interference fit.

[0017] Furthermore, the bottom of the lower cap extends downwards with connection pins that can be plugged into and soldered onto the PCB board.

[0018] By adopting the above solution, this utility model has at least the following technical effects:

[0019] 1. The cap body and connecting piece in the upper cap are integrally molded, ensuring a stable connection and eliminating the risk of the connecting piece coming loose.

[0020] 2. The connecting piece is a piece with width. Compared with the tail wire with a smaller diameter in the prior art, the connecting piece in this utility model can be modified according to the actual specifications of the fuse during production, and the heat dissipation effect is better.

[0021] 3. Through the interference fit between the protrusion and the PCB board, the vertical fuse can stand stably on the PCB board, improving the welding stability.

[0022] 4. Based on point 3, the vertical fuse of this utility model does not require a base to maintain stability when soldered onto the PCB board, making the overall structure simpler. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of the vertical fuse of this utility model;

[0024] Figure 2 This is a schematic diagram of the structure of the upper cap of this utility model;

[0025] Figure 3 This is a schematic diagram of the vertical fuse of this utility model mounted on a PCB board;

[0026] Figure 4 for Figure 3 A magnified view of a section at point A in the middle;

[0027] Figure 5 for Figure 3 A sectional view.

[0028] Explanation of icon numbers:

[0029] 1. Tube body; 2. Upper cap; 21. Cap body; 22. Connecting piece; 221. Horizontal piece body; 222. Support piece body; 23. Pin; 231. Protrusion; 3. Lower cap; 31. Connecting pin; 4. PCB board. Detailed Implementation

[0030] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0031] Combination Figures 1 to 3 As shown, this utility model discloses a vertical fuse, which includes an upper cap 2 and a lower cap 3 installed at the upper and lower ends of a vertical tube 1, respectively. The upper cap 2 includes a cap body 21 fitted onto the upper end of the tube 1. A connecting piece 22 is integrally formed on the cap body 21 and supports the outside of the tube 1. The bottom of the connecting piece 22 is provided with a flat pin 23 for insertion and soldering onto a PCB board 4. The pin 23 is provided with at least one protrusion 231. When the pin 23 is inserted into the insertion hole (not shown in the figure) on the PCB board 4, the protrusion 231 and the insertion hole 41 achieve an interference fit.

[0032] The tube body 1 is an insulated tube with open ends. A fusible element (not shown in the figure) is placed inside the tube body 1. The two ends of the fusible element can be fixed to the cap body 21 of the upper cap 2 and the cap 3 of the lower cap 3 by soldering. The cap body 21 of the upper cap 2 and the cap 3 of the lower cap 3 can be fixed to the two ends of the tube body 1 by interference fit. In this utility model, the tube body 1 is vertical on the PCB board, and the lower cap 3 is located above the PCB board 4. The bottom of the lower cap 3 extends downward with a connecting pin 31 that can be plugged into and soldered to the PCB board 4. The lower cap 3 can be directly soldered to the PCB board 4.

[0033] In this embodiment, the connecting piece 22 forms an L-shaped piece. The connecting piece 22 includes a transverse piece 221 extending outward from the outer wall of the cap body. The outer end of the transverse piece 221 extends vertically downward to form an upright support piece 222. The pin 23 is located at the bottom of the support piece 222. In this embodiment, the cap body forms a circular cap body with an open bottom. The transverse piece 221 extends horizontally outward from the outer wall of the cap body 21 at intervals. The support piece 22 is parallel to the outside of the vertical tube 1, forming a relatively stable support and facilitating heat dissipation of the connecting piece. The length of the support piece 22 is designed according to the overall height of the fuse, corresponding to the requirement that the pin 23 can be inserted into the insertion hole.

[0034] Furthermore, both the transverse plate 221 and the support plate 222 can be flat plates with a certain width, and the width of the pin 23 is smaller than the width of the support plate 222. In this embodiment, both the transverse plate 221 and the support plate 222 are thin, elongated, flat cuboids, and the cross-sectional area of ​​the connecting piece (the width of the transverse plate 221 and the support plate 222) can be increased according to the specific fuse current specification to achieve better heat dissipation, ensuring that the highest temperature point of the fuse during operation is in the middle of the tube, rather than concentrated at the upper cap, causing the solder inside the upper cap to form an M-effect point and melt prematurely. Moreover, the connecting piece 22 does not need to be bent and riveted to the upper cap, eliminating the risk of loosening. In addition, if the tail wire is connected to the upper end cap by riveting, in order to ensure the stability of the riveting point, the bent part of the tail wire extending upward and then bending downward from the riveting point (the inverted U-shaped connecting section) needs to be at least 3mm away from the riveting point. Therefore, the tail wire also needs to be at least 3mm higher than the upper end cap. However, in this embodiment, since the connecting piece 22 is not connected to the upper end cap by riveting, the horizontal piece 221 extends directly outward from the cap body 21, and does not need to be at least 3mm higher than the upper end cap. This can save the height after the fuse is soldered to the PCB board.

[0035] Further reading Figures 3 to 5 As shown, when pin 23 is inserted into the insertion hole of PCB board 4, the protrusion 231 and the insertion hole in PCB board 4 are interference-fitted, which allows the connecting piece 22 to be firmly locked onto PCB board 4. In this embodiment, the protrusion 231 is provided on the side wall of pin 23. The protrusion 231 can be provided on one side wall of pin 23, or it can be provided on both side walls of pin 23. The protrusion 231 forms an elongated ridge, and the surface of the protrusion 231 abuts against the inner wall of the insertion hole. The elongated design allows for a larger area of ​​contact between the surface of the protrusion 231 and the inner wall of the insertion hole, resulting in a more secure insertion and increased stability during soldering.

[0036] With the above structure, in the vertical fuse of this invention, the upper cap 2 is fixed to the upper end of the tube body by a cap body 21. A connecting piece extends integrally from the outer side of the cap body, supporting the PCB board. The lower end of the connecting piece is directly inserted into the insertion hole of the PCB board 4 through a pin 23. The protrusion 231 on the pin 23 can be locked onto the PCB board 4 to achieve an interference fit, thereby achieving stable standing on the PCB board 4 and improving the welding stability between the vertical fuse and the PCB board 4. Compared with the prior art, this invention not only solves the defects of vertical fuses with narrow horizontal widths being prone to instability and unstable welding on the PCB board, but also eliminates the need for additional bases or other structures to maintain stability, and the structure is relatively simple.

[0037] The above is merely one embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A vertical fuse, comprising an upper cap and a lower cap respectively installed at the upper and lower ends of a vertical tube, characterized in that: The upper cap includes a cap body that is attached to the upper end of the tube body. A connecting piece is integrally formed on the cap body and supports the outside of the tube body. The bottom of the connecting piece is provided with a flat pin for insertion and soldering onto the PCB board. The pin is provided with at least one protrusion. When the pin is inserted into the insertion hole on the PCB board, the protrusion and the insertion hole achieve an interference fit. The protrusion is located on the side wall of the pin, and the protrusion is a long strip-shaped ridge; The surface of the protrusion abuts against the inner wall of the insertion hole; The bottom of the lower cap extends downwards with connection pins that can be plugged into and soldered onto the PCB board. The lower cap is directly soldered onto the PCB board.

2. A vertical fuse according to claim 1, characterized in that: The connecting piece includes a transverse piece extending outward from the outer wall of the cap body, with the outer end of the transverse piece extending vertically downward to form an upright support piece, and the pins located at the bottom of the support piece.

3. A vertical fuse according to claim 2, characterized in that: The horizontal plate extends horizontally outward from the outer wall of the cap body by a certain distance, and the support plate is parallel to the outside of the vertical tube body, and the length of the support plate corresponds to the pin that can be inserted into the plug hole.

4. A vertical fuse according to claim 2 or 3, characterized in that: Both the transverse sheet and the support sheet are flat sheets with width.

5. A vertical fuse according to claim 4, characterized in that: The width of the pin is smaller than the width of the support plate.

6. A vertical fuse according to claim 1 or 2, characterized in that: The cap body at the top and the cap at the bottom are respectively fitted onto the two ends of the tube body by an interference fit.

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