CN201204105Y - Explosion-proof resistor - Google Patents

Abstract

An explosion-proof resistor includes a ceramic body, two metal wires, a metal winding and a protective sleeve. The ceramic body includes a rod body and two end caps, the two ends of the rod body are connected to each end cap; one end of each metal wire is electrically connected to each end cap; the metal winding is wound around the rod body, and the two ends of the metal winding are electrically connected to each end cap; the completed body is sealed in the protective sleeve with non-flammable resin. When the overload current passes through the explosion-proof resistor and exceeds the critical value, the metal winding will be fused to block the load current from passing through, and pass through the protective sleeve to provide a safe protection effect.

Description

Explosion-proof resistance

Technical field

The utility model is about a kind of resistance, particularly a kind of have prevent at the moment high current loads, produce the explosion-proof resistance of explosion or meltdown when resistive element is overheated.

Background technology

Resistance is one of basic application element thereof common on electronic installation or the circuit board, be mainly used to regulate or distributor circuit on curtage.When electric current passes through resistance, can be because impedance conversion be a heat energy.Though can developing according to design requirement or material difference, resistance various dissimilar resistance (formula of for example boring a hole or surface adhesive type), but the curtage that general resistance can bear all has its limiting value, if provide to the curtage of resistance has surpassed this limiting value, produce a large amount of heat energy with making power that resistance produced rise and being accompanied by, it is overheated and damage to be easy to regard to causing resistance, even burns circuit board or electronic installation.For example, when opening and closing electronic device power or thunderbolt, the surging (surge) that resistance produced is influenced, or make resistance be in the situation of continuous load, may make that all resistance damages because of overheated.In order to improve this type of situation, many dealers are improved at the small size electric resistance structure that circuit board is used.

With the wire resistor is example; the design that can fuse when utilizing resistance overheated and wind the line; make electric current can't continue by to reduce the risk that it may cause; but common wire resistor only applies one deck insulating protective layer from the teeth outwards and is solidificated in its surface; with the influence of isolated outer bound pair resistance, this protective layer only provides small protection effect, in case excessive by the electric current of element; resistance may burn or explosion because of overheated moment, will cause circuit board short circuit or infringement or thereby cause fire.

Also have the dealer to design the resistance of film-type in addition to replace coiling, though this quasi-resistance needn't be worried the problem of explosion when electric current is excessive, but because of the materials limitations of film itself, make that resistance that this quasi-resistance provided is the highest and only reach 1 ohm, bigger resistance value can't be provided; And when the load current that flows through resistance was excessive, its protection mechanism can't be blocked the electric current by resistance fully, therefore will make the overheated possibility that meltdown is arranged of resistance will cause local fire what is more under the condition that long-time electric current passes through.

Therefore, in order to solve above-mentioned prior art problem, and produce conception of the present utility model.

Summary of the invention

Main purpose of the present utility model is providing a kind of explosion-proof resistance that produces explosion or meltdown when preventing that resistance is overheated that has.

For reaching above-mentioned purpose, explosion-proof resistance of the present utility model comprises body, two plain conductors, metal coiling and protection tubes.Body comprises the body of rod and two end caps, and the two ends of the body of rod are connected with each end cap; One end of each plain conductor electrically connects with each end cap respectively; The metal coiling is wound in the body of rod, and the two ends of metal coiling electrically connect with each end cap respectively; Body is sealed in the protection tube.When load current by explosion-proof resistance, and when surpassing critical value, metal coiling meeting is fused to be passed through with the blocking-up load current, and by protection tube so that protection effect to be provided.Design whereby to improve the safety in utilization of explosion-proof resistance of the present utility model.

In the above-mentioned explosion-proof resistance, this body can be sealed in this protection tube by encapsulating material.

In the above-mentioned explosion-proof resistance, this encapsulating material can be the fire-retardant type thermosets.

In the above-mentioned explosion-proof resistance, this protection tube or this body useful ceramics material are made.

In the above-mentioned explosion-proof resistance, the square root of the resistivity of this metal coiling can be inversely proportional to this load current.

In the above-mentioned explosion-proof resistance, the line footpath of this metal coiling can be directly proportional with this load current.

In the above-mentioned explosion-proof resistance, the square root of the line length of this metal coiling can be inversely proportional to this load current.

The beneficial effects of the utility model are: by coiling of the metal of fusible and protection tube seal body, so that the security protection of explosion-proof resistance of the present utility model when load current is excessive to be provided, and can to block load current fully and pass through after metal coiling fusing.

Description of drawings

Fig. 1 is the stereogram of explosion-proof resistance of the present utility model.

Fig. 2 is the cutaway view of explosion-proof resistance of the present utility model.

Fig. 3 is the manufacture method flow chart of explosion-proof resistance of the present utility model.

Wherein, description of reference numerals is as follows:

Explosion-proof resistance 1

Body 10 bodies of rod 12

End cap 14 plain conductors 20

Metal 30 hollow sleeves 40 that wind the line

Encapsulating material 50

Circuit board 100

Embodiment

For allowing above-mentioned and other purposes, feature and advantage of the present utility model become apparent, below especially exemplified by going out specific embodiment of the utility model, and conjunction with figs. is carried out following detailed description.

Please refer to Fig. 1, this figure is the stereogram of explosion-proof resistance of the present utility model.As shown in Figure 1, explosion-proof resistance 1 of the present utility model comprises body 10, two plain conductors 20, metal coiling 30 and protection tubes 40.Body 10 can adopt ceramic material to make.Body 10 comprises the body of rod 12 and two end caps 14, and the two ends of the body of rod 12 are connected with each end cap 14.One end of each lead 20 electrically connects with each end cap 14 respectively.Metal coiling 30 is wound in the body of rod 12, and the two ends of metal coiling 30 electrically connect with each end cap 14 respectively.Body 10 is sealed in the protection tube 40.Each end cap 14 can be as electrode, and is electrically connected to each other to form the load current paths by explosion-proof resistance 1 by plain conductor 20, end cap 14 and metal coiling 30.

One of them flows into explosion-proof resistance 1 from two plain conductors when load current, and when surpassing critical value by explosion-proof resistance 1, and metal coiling 30 can be passed through with the blocking-up load current by fusing, and by protection tube 40 so that protection effect to be provided.Design whereby, can improve explosion-proof resistance 1 of the present utility model fail safe in the use, if the situation of super-high-current by explosion-proof resistance 1 takes place, metal coiling 30 will and can utilize protection tube 40 that explosion-proof isolated effect is provided by fusing, and can circuit board or other electronic components not caused damage; This kind design simultaneously is applicable to the resistance of small size, to save usage space and to help being arranged on the circuit board.Protection tube 40 is made with ceramic material, the protection effect when using its resistant to elevated temperatures characteristic and crossing thermal spalling so that explosion-proof resistance 1 to be provided, but protection tube 40 also can use other heat proof materials to replace, and the utility model is not as limit.

Please refer to Fig. 2, this figure is the cutaway view of explosion-proof resistance of the present utility model.As shown in Figure 2, explosion-proof resistance 1 of the present utility model can be used and be arranged on the circuit board 100, makes explosion-proof resistance 1 and circuit board 100 electrically connect by plain conductor 20.The body 10 of explosion-proof resistance 1 is sealed to be placed in the protection tube 40 of hollow, and by encapsulating material 50 body 10 is sealed in the protection tube 40.In the present embodiment, encapsulating material can adopt the fire-retardant type thermosets, make explosion-proof resistance 1 of the present utility model under the situation of overheated generation high temperature, keep the sealing state of protection tube 40 by the characteristic of fire-retardant type thermosets, thereby improve the fail safe in the use of explosion-proof resistance 1.

The parameter correlation of explosion-proof resistance 1 allowed load current that passes through of the present utility model and metal coiling 30.Explosion-proof resistance 1 of the present utility model is gone up the environment that exchanges surging (AC surge) and direct current constant load (DC constant load) applicable to producing in design, derivation by mathematical formulae, can obtain under the situation that exchanges surging and direct current constant load, the parameter of the load current of the explosion-proof resistance 1 of flowing through and metal coiling 30 has the corresponding relation of following formula:

$I_0{e}^{-t/\mathrm{RC}}+I_0\sin \mathrm{\&omega;t}=0.886D\&CenterDot;{\mathrm{\&Delta;<figure-callout\; id="1"\; label="T"\; filenames="Y200820116166E00081.png"\; state="\{\{state\}\}">T</figure-callout>}}^{1/2}\&CenterDot;{R_T}^{-1/2}\&CenterDot;{\left({\mathrm{\&rho;}}_{R}L\right)}^{-1/2}$

In the above-mentioned relation formula, I ₀Be the momentary load electric current, D is the line footpath of metal coiling 30, ρ _RBe the resistivity (impedance factor) of metal coiling 30, L is the line length of metal coiling 30, R _TBe system's thermal resistance of element, △ T is the molten solubility temperature of resistive conductor.Hence one can see that, moment maximum load current directly be directly proportional with the line of metal coiling 30, and the wind the line square root of 30 resistivity or the square root of line length of load current and metal is inversely proportional to; When unlike material is selected in metal coiling 30 for use, have different resistivity, different molten solubility temperatures is promptly arranged,, will produce change to the resistance of explosion-proof resistance 1, thereby influence the load current value that explosion-proof resistance 1 is passed through in length that changes metal coiling 30 or line footpath.In other words, explosion-proof resistance 1 of the present utility model can be adjusted length, material or the line footpath of metal coiling 30, to obtain best resistance usefulness according to different electric current demands.

Please refer to Fig. 3, this figure is the manufacture method flow chart of explosion-proof resistance 1 of the present utility model.As shown in Figure 3, the manufacture method of explosion-proof resistance of the present utility model may further comprise the steps:

Step 110: the body of rod and two end caps are provided, the two ends of the body of rod are connected each end cap respectively to form body.As shown in Figure 1, the body of rod 12 can utilize modes such as gummed or welding to combine with 14 of end caps, with the body 10 that forms explosion-proof resistance 1 of the present utility model.

Step 120: two plain conductors are provided, an end of each plain conductor is electrically connected each end cap respectively.As shown in Figures 1 and 2, an end of each plain conductor 20 is connected on each end cap 14, makes that plain conductor 20 and end cap 14 can keep electrically connecting.Each plain conductor 20 can be connected in each end cap 14 by welding manner, and the other end of each plain conductor 20 can be incorporated on the circuit board 100 according to circuit design.

Step 130: the metal coiling is provided, the metal coiling is wound in the body of rod, and the two ends of metal coiling are electrically connected with each end cap respectively.As shown in Figure 1, metal 30 ring-types that wind the line are wound on the body of rod 12, and the two ends of metal coiling 30 are connected with each end cap 14, make metal coiling 30 and end cap 14 can keep electrically connecting, wind the line 30 to form load current path by explosion-proof resistance 1 by plain conductor 20, end cap 14 and metal.Metal coiling 30 by the material that changes metal coiling 30, line footpath or line length, can produce different resistances for the main resistance source of explosion-proof resistance 1 is provided, therefore can be according to different electric current demands, to adjust the resistance usefulness of explosion-proof resistance 1.

At last, carry out step 140: protection tube is provided, body is sealed in the protection tube.As shown in Figures 1 and 2, will embed in the protection tube 40 of hollows, again protection tube 40 be sealed action, and make body 10 be sealed in the protection tube 40, to promote the protection effect of explosion-proof resistance 1 through the body after the abovementioned steps combination 10.This step can be sealed by the protection tube 40 both ends open places of encapsulating material 50 at ccontaining body 10, and with the seal of maintenance protection tube 40 inside, but each plain conductor 20 passes encapsulating material 50 and stretches out.Encapsulating material 50 can be the fire-retardant type thermosets.Overheated and the situation of explosion may occur the time, coverage can be confined to protection tube 40 inside when explosion-proof resistance 1 whereby, can not cause damage to circuit board 100 or electronic installation itself.

In sum, no matter the utility model all shows it totally different in the feature of prior art with regard to purpose, means and effect.But must notice that the foregoing description only is used for principle of the present utility model and effect thereof are described illustratively, but not is used to limit scope of the present utility model.Any those skilled in the art all can be under know-why of the present utility model and spirit, and embodiment is made an amendment and changes.Rights protection scope of the present utility model should be as described in claims.

Claims (7)

1. An explosion-proof resistor, characterized in that it comprises: The body includes a rod body and two end caps, and the two ends of the rod body are connected to the end caps; two metal wires, one end of each of the metal wires is electrically connected to each of the end caps; a metal winding wire wound around the rod body, the two ends of the metal winding wire are respectively electrically connected to the end caps; and a protective sleeve, the body is sealed in the protective sleeve; When the load current flows into the explosion-proof resistor from one of the two metal wires, and when passing through the explosion-proof resistor exceeds the critical value, the metal winding will be fused to block the load current from passing through, and pass through the protective sleeve to Provides protection. 2. The explosion-proof resistor according to claim 1, characterized in that: the body is sealed in the protective sleeve by means of a packaging material. 3. The explosion-proof resistor according to claim 2, characterized in that: the packaging material is a non-combustible thermosetting material. 4. The explosion-proof resistor according to claim 1, characterized in that: the protective sleeve or the body is made of ceramic material. 5. The explosion-proof resistor as claimed in claim 1, wherein the square root of the resistivity of the metal winding is inversely proportional to the load current. 6. The explosion-proof resistor as claimed in claim 1, characterized in that: the wire diameter of the metal winding is proportional to the load current. 7. The explosion-proof resistor as claimed in claim 1, wherein the square root of the wire length of the metal winding is inversely proportional to the load current.

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