Surface mounting fuse protector and manufacturing approach thereof
Technical field
The present invention relates to a kind of surface mounting fuse protector and manufacturing approach thereof, relate in particular to small-sized surface mounting fuse protector of a kind of unsettled lead-type and manufacturing approach thereof.
Background technology
Current, how printed circuit board (PCB) is is applied in the various electric and electronic equipments.The circuit that on these printed circuit board (PCB)s, forms generally all needs overcurrent protection.One of mode that this overcurrent protection is provided is to use the small-sized surface mounting fuse protector that is fixed on the printed circuit board (PCB).
Present small-sized surface mounting fuse protector mainly contains two major types.One type is solid state device type (Solid Body), and another kind of is unsettled lead-type (Wire-In-Air).
The characteristics of the fuse of solid state device type are that fuse (fuse element) is embedded in support on every side or the arc quenching material to form solid structure.In the United States Patent (USP) of listing below, couple description of the fuse of solid state device type: US 5,228,188,5,296,833,5,726 is arranged, 621,5,432,378,5,943,764,5,440,802,6,002,322,6,034,589,7,268,661.The fuse of this type can be done very for a short time, can on big plate base, process the matrix of a plurality of fuses simultaneously, has higher production efficiency.But because fuse is higher to the rate of heat transfer of the periphery material of being close to, under the requirement of certain blowout current, fuse will have bigger resistance could produce enough heats with fuse failure.
U.S. Pat 6,002,322 have disclosed a kind of structure and production method thereof of typical solid device type surface mounting fuse protector.This method is made the matrix of a plurality of fuses on the macromolecule sheet material of monolithic, and then cuts into single fuse.This method production efficiency is higher, but can only produce the surface mounting fuse protector of solid state device type, and its fuse is close on the substrate, and rate of heat transfer is higher, and the bigger energy of needs could be with fuse failure.
The caloric value of the fuse of fuse can be expressed with following equation:
Q=I
2Rt
Wherein Q is a caloric value, and I is an electric current, and R is a resistance, and t is the time.The fuse of specific protective current has certain regulation to electric current I and fusing time t.When the fusing heat Q of needs was big more, resistance R was just big more.Can only make fuse through this method and be close to the fuse on the substrate, higher rate of heat transfer causes the increase of required heat energy and resistance.
The fuse that resistance is bigger can consume bigger electric energy on electronic circuit.In adopting battery powered electrical equipment, use the bigger fuse of resistance that reduced the service time of battery.
The midget fuse of unsettled lead-type is that fuse (lead) is suspended in the shell of hollow.The two ends of fuse are fixing in a different manner with the termination electrode.Because the thermal transmission coefficient of air is much littler than most solid, therefore the less energy of the fuse of unsettled lead-type needs just can be with fuse failure, and its resistance can also be less.The fuse of this type has detailed explanation: US 5,617,069,5,648,750,5,214,406,5,926,084,6,147,585,6,903,649,4,920,327,4,467,308,3,460,086,6,798,330 in following United States Patent (USP).These patents of invention have described how fuse is fixed on the distinct methods in the cavity, and its purpose is to avoid contacting of fuse stage casing and chamber wall more, to the stress that fuse applied, increase reliability that fuse is connected with the termination etc. when reducing to install.The fuse of this type adopts earthenware and metal cap parts to assemble one by one at present, and production efficiency is lower.
U.S. Pat 5,214,406 have disclosed a kind of structure of typical unsettled lead-type surface mounting fuse protector.This fuse comprises the shell of circle foreign side in, two termination metal caps, and two ends are welded on the fuse on the two ends metal cap.This fuse has the characteristics of unsettled lead-type fuse, because the peritropous rate of heat transfer of unsettled lead (fuse) is lower, required fusing heat is less, so its resistance also can be done lessly.
But said as above-mentioned document US 5,214,406, the fuse of many unsettled lead-type fuses is tiny easily broken, and certain difficulty is arranged when mounted.For guarantee fuse except that two ends not with the influence of housing contacts to avoid conducting heat to operating chacteristics, have to again the bending two ends of fuse is fixed on the end face at two diagonal angles.When being pressed into two ends copper cap, the friction between copper cap and fuse can produce tension force to fuse.These bendings and tension force all possibly make tiny easily broken fuse produce distortion or fracture.There are the shell of constant slope, the tension force that when being pressed into to reduce the copper cap fuse is produced in the improvement design employing two ends of this prior art.But copper cap and housing contacts will have enough friction can not come off when installing and use to guarantee the copper cap.This just must make the inside dimension of copper cap be less than the external dimensions with the housing contacts place.The design of this fuse can reduce but can not eliminate the tension force that when being pressed into two ends copper cap, fuse is produced.And the minimizing of this tension force that fuse is produced is to be cost with the minimizing of copper cap and the friction of housing contacts and the reliability that is connected.Improvement design in the above-mentioned document is with scolding tin the fuse two ends to be welded on two terminations.But this improvement design also can not be eliminated because of the fuse bending two ends and cause the injury possible to fuse.And scolding tin when fusion can with fuse materials commonly used, like copper, form low-melting alloy.The formation of this low-melting alloy can reduce the consistency of fuse blows characteristic.In addition, this fuse need adopt the method for assembling one by one to be assembled, and production efficiency is lower.
Summary of the invention
The small-sized surface mounting fuse protector and the manufacturing approach thereof that the purpose of this invention is to provide a kind of unsettled lead-type; Thereby when keeping advantages such as unsettled lead-type fuse is little with respect to solid state device type resistive fuse, power consumption is low; Eliminate when making the bending of fuse and the tension force that is produced; And avoid producing low-melting alloy, improve reliability of products and consistency.In addition, can produce above-mentioned fuse fast, in large quantities through corresponding method of manufacture.
First aspect of the present invention relates to a kind of surface mounting fuse protector, and this surface mounting fuse protector comprises: upper substrate, and an end in this upper substrate outside is provided with first termination electrode, and the other end is provided with second termination electrode, and the inboard middle part of this upper substrate is provided with first cavity; Infrabasal plate; One end in this infrabasal plate outside is provided with and the corresponding three-end electrode of said first termination electrode; The other end is provided with four termination electrode corresponding with said second termination electrode; The inboard middle part of this infrabasal plate is provided with and corresponding second cavity of said first cavity, and the common cavity that forms of said first and second cavity; Fuse, this fuse clip are located between the said upper and lower substrate, the part of this fuse is suspended in the said cavity; One end of said first termination electrode, three-end electrode and said fuse is electrically connected, and the other end of said second termination electrode, the 4th termination electrode and said fuse is electrically connected.
This surface mounting fuse protector can guarantee that metal fuse is fixed on the middle part of cavity, has reduced its rate of heat transfer to periphery, thereby reduces required fusing energy and resistance.
The surface mounting fuse protector of above-mentioned first aspect according to the present invention; Also can preferably be set to: the said fuse said cavity of process also suspends in said cavity; And the both ends of said fuse extend to the side, two ends that is provided with first and second termination electrode of said surface mounting fuse protector respectively, and the respective end portions of said first and second termination electrode and said fuse is electrically connected through the plating belt that is located at the respective ends side respectively.
The metal that said plating belt fusing point capable of using is higher than scolding tin forms through chemical plating or plating.
According to above-mentioned preferred version, the two ends of fuse make it form reliable the connection with four termination electrodes at fuse two ends with the method for plating, and the fusing point of metal lining is higher than the fusing point of fuse, can prevent to produce low-melting alloy.
Second aspect of the present invention relates to a kind of method of making the surface mounting fuse protector of first aspect present invention, and this method comprises the steps:
(i) prepare upper and lower substrate and fuse, be equipped with termination electrode at the two ends in the said upper and lower substrate outside;
(ii) respectively at the corresponding cavity of the inboard formation of said upper and lower substrate;
(iii) said fuse is placed said upper substrate or said infrabasal plate inboard, the part of this fuse is suspended in this cavity;
Inboard that (iv) will this upper and lower substrate aligns applying, and said fuse is suspended in by in the formed cavity of the cavity of this upper and lower substrate, and the respective ends lateral ends that is positioned at of the upper and lower substrate outside corresponding termination electrode in two ends and said fuse is electrically connected.
When utilizing above-mentioned manufacturing approach to produce surface mounting fuse protector of the present invention, fuse is not carried out bending, the tension force that acts on the fuse is also very little, can effectively keep its intensity, prevents fracture.
The third aspect of the invention relates to a kind of method of making the surface mounting fuse protector of a plurality of first aspect present invention, and this method comprises the steps:
(a) preparation is provided with first and second baseplate material plate and fuse of electrode material on a side;
(b) electrode material on first and second baseplate material plate is processed to form the termination electrode pattern;
(c) opposite side at first and second baseplate material plate is provided with cavity array and intercommunicating pore array; Make each said intercommunicating pore all pass the electrode material of said termination electrode pattern; And each said cavity be equipped with said intercommunicating pore with the corresponding two ends of said termination electrode pattern, thereby said cavity and said intercommunicating pore arrange in a row;
(d) lateral root that is provided with the cavity array of a baseplate material plate is provided with fuse according to said cavity and the said intercommunicating pore of arranging of embarking on journey therein, makes each said fuse pass through in the said cavity array the said intercommunicating pore of cavity and said cavity two ends accordingly respectively;
(e) side that is provided with the cavity array with the said first and second baseplate material plates aligns applying; Make the corresponding common respectively cavity that forms of cavity on each cavity and the said second baseplate material plate on the said first baseplate material plate; Said fuse is through settings that suspend of the part of each said cavity, and makes in the said first and second baseplate material plates that intercommunicating pore is communicated with respectively accordingly;
(f) said intercommunicating pore being carried out plating handles; This plating is handled the intercommunicating pore that in step (c), is directed against said first and second baseplate material plate and is carried out respectively; Perhaps in step (e), said first and second baseplate material plate aligned and carry out to the said intercommunicating pore that is communicated with respectively after fitting, thereby make the electrode material and form on the said first and second baseplate material plates that align applying be electrically connected through the said fuse of said intercommunicating pore;
(g) correspondingly cut according to said cavity array and said intercommunicating pore array for the said first and second baseplate material buttresses, thereby form a plurality of said surface mounting fuse protectors.
This method can be made a plurality of fuses simultaneously on two bigger polymeric substrates, through being cut into single fuse separately, production method is simple, improves the production efficiency of having produced small-sized unsettled lead-type surface mounting fuse protector, the corresponding cost that reduced.
The method of the above-mentioned third aspect according to the present invention; Also can be preferably before in said step (g); Plate the nickel dam and the soldering-tin layer of protection on the surface of the coating that after said plating is handled, forms and the surface of termination electrode pattern successively, to guarantee the reliability and the solderability of termination electrode.
Description of drawings
Fig. 1 is that surface mounting fuse protector of the present invention is welded in the stereogram on the circuit pattern of circuit board;
Fig. 2 is the stereogram of surface mounting fuse protector of the present invention;
Fig. 3 is the sectional block diagram of surface mounting fuse protector of the present invention;
Fig. 4 is the longitudinal sectional view of surface mounting fuse protector of the present invention;
Fig. 5 is the key diagram of manufacturing terminal electrode pattern when making surface mounting fuse protector of the present invention;
Fig. 6 is the partial enlarged drawing of Fig. 5;
Fig. 7 is a key diagram of making intercommunicating pore array and cavity array when making surface mounting fuse protector of the present invention;
Fig. 8 is the partial enlarged drawing of Fig. 7;
Fig. 9 is a key diagram of making the groove of sunkening cord when making surface mounting fuse protector of the present invention;
Figure 10 is the partial enlarged drawing of Fig. 9;
Figure 11 aligns the local longitudinal sectional view after fitting together with two baseplate materials and fuse when making surface mounting fuse protector of the present invention;
Figure 12 is the transverse cut of expression when cutting for fuse array when making surface mounting fuse protector of the present invention and the vertical key diagram of line of cut;
Figure 13 is the operating chacteristics curve chart of an instance of surface mounting fuse protector of the present invention;
Figure 14 is the operating chacteristics curve chart of another instance of surface mounting fuse protector of the present invention.
Embodiment
Below, with reference to accompanying drawing 1-14 the concrete structure and the manufacturing approach of surface mounting fuse protector of the present invention are elaborated.
The concrete structure of surface mounting fuse protector of the present invention
Referring to Fig. 1-4, surface mounting fuse protector 1 of the present invention comprises the upper and lower substrate 100,200 that constitutes its shell and unsettled fuse 1000 between these two substrates.The two ends in upper and lower substrate 100,200 outsides are respectively equipped with termination electrode 300,500,400,600; Wherein two of infrabasal plate 200 termination electrodes 400,600 for example are fixed on the circuit pattern that separates 3 on the circuit board 2 through welding respectively, and the circuit pattern 3 that separates is electrically connected through the fuse 1000 of fuse 1.Reach predetermined value like electric current, fuse 1000 disconnection that will fuse, thus to the circuit on the circuit board 2 overcurrent protection is provided.
The monnolithic case of upper and lower substrate 100,200 is basic identical, all is roughly parallelepiped shape, and the length and width size is basic identical.Be located at respectively upper and lower substrate 100,200 substantially the termination electrode 300,500,400,600 at smooth lateral surface two ends can process by metal such as copper or other electric conducting material.
The medial surface of upper and lower substrate 100,200 can through mill, machine-tooled method such as punching press forms cavity 901,902 respectively.After upper and lower substrate 100,200 was assembled together, corresponding cavity 901,902 can constitute cavity 900, was used for the unsettled fuse 1000 that is provided with.
Two ends at the cavity 902 of infrabasal plate 200 are respectively equipped with the groove 1001 of sunkening cord, and are used to locate fuse 1000.The groove 1001 of sunkening cord extends outwardly into infrabasal plate 200 corresponding end side surface from the end of cavity 902.Certainly, this groove 1001 of sunkening cord also can be located on the relevant position of upper substrate 100, or upper and lower substrate 100,200 all correspondingly is provided with the groove 1001 of sunkening cord.
Fuse 1000 unsettled being arranged in the cavity 900, and place the groove 1001 of sunkening cord at cavity 900 two ends, and extend to the corresponding end side surface of upper and lower substrate 100,200 always.The part that the medial surface of upper and lower substrate 100,200 is fitted each other be applied with adhesive 1100 and the groove 1001 of sunkening cord in be applied with adhesive 150; Fixing so that upper and lower substrate 100,200 connects reliably, and make fuse 1000 reliably be positioned to sunken cord in the groove 1001.
Certainly, the groove 1001 of sunkening cord can be set according to circumstances yet, but fuse 1000 direct folders be established the medial surface that is fixed on two substrates 100,200 and it is suspended in the cavity 900 through adhesive 1100.
Also be respectively equipped with plating belt 700,800 in the side, two ends of upper and lower substrate 100,200, thereby the both ends that extend to the fuse 1000 of two substrates 100,200 respective ends sides respectively with the termination electrode 300,500,400,600 at upper and lower substrate 100,200 two ends and via the groove 1001 of sunkening cord are electrically connected.Like this; When this fuse 1 for example is fixed on 2 last times of circuit board through two end electrodes 400,600 is welded on the circuit pattern 3 separately, two circuit patterns that separate 3 form via two end electrodes 400,600, plating belt 700,800 and fuse 1000 and are electrically connected.
Plating belt 700,800 can use copper and/or nickel to form through chemical plating or electric plating method, can certainly adopt other metal depositions.Metal lining has the fusing point higher than scolding tin, thereby forms the connection that better heat resistance is arranged than scolding tin.In addition, adopt metal deposition to connect and also avoided forming the possible of low-melting alloy, thereby make the operating chacteristics of fuse more consistent through being welded to connect the scolding tin and the fuse that cause.Can certainly adopt other electric connection mode commonly used except that plating.
In order to guarantee the solderability of termination electrode, cover soldering-tin layer on the surface of the termination electrode on the circuit pattern that separates 3 that will be welded on the circuit board 2 with plating or plating and wave-soldering at least, on the surface of plating belt 700,800, also soldering-tin layer can be set.If termination electrode 300,500,400,600 and plating belt 700,800 are for example formed by copper, directly the covering soldering-tin layer can produce low-melting alloy and copper is melted on the surface of copper, thereby influences the performance of fuse.In this case, need before covering soldering-tin layer, plate the nickel that one deck shields on the surface of copper through electroplating.
Introduce two embodiment of the method for producing surface mounting fuse protector 1 of the present invention below.
Embodiment 1
The fuse 1 of making the invention described above can comprise the steps.
Prepare two insulation boards (macromolecular material plates such as thermoplasticity or thermoset plastics) as upper and lower substrate 100,200, and adhere to Copper Foil to form termination electrode 300,500,400,600 at the two ends of the one side of substrate 100,200.Also can prepare the substrate that one side is stained with Copper Foil, then adopt the method for electrochemical corrosion or machining to remove the part Copper Foil and process the termination electrode 300,500,400,600 of the separation at two ends.Certainly, termination electrode 300,500,400,600 also can be formed by other electric conducting material.
At the opposite side that does not form termination electrode of upper and lower substrate 100,200, use mechanical means, as mill, punching press etc. processes corresponding cavity 901,902.
In the one side that is formed with cavity of one of them substrate of upper and lower substrate 100,200, use mechanical means, process the groove 1001 of sunkening cord that is positioned at the cavity midline position as sawing, mill etc.The groove 1001 of sunkening cord extends to the end side surface of substrate correspondence respectively from the two ends of cavity.In the groove 1001 of sunkening cord, imbed fuse 1000, and make fuse 1000 extend to the side, two ends of upper and lower substrate 100,200.Fuse 1000 is processed with metal, alloy, composition metal or metal and nonmetal recombination line.
Coating binder 1100 on the surface that is formed with cavity 901,902 of upper and lower substrate 100,200 also scribble adhesive 150 in the fuse 1000 and groove 1001 contact portions of sunkening cord, and in the cavity part, fuse 1000 keeps unsettled.Align upper and lower substrate 100,200 bonding.Fuse 1000 can not receive bending and extruding in installation process.
Certainly, the groove 1001 of sunkening cord can be set according to circumstances yet, but fuse 1000 direct folders be established the medial surface that is fixed on two substrates 100,200 and it is suspended in the cavity 900 that is made up of cavity 901,902 through adhesive 1100.
Make fuse 1000 be electrically connected then with the termination electrode 300,500,400,600 at fuse two ends about in the of 1.For example can be with the presumptive area activation of the side, two ends of upper and lower substrate 100,200, realize being electrically connected with chemical plating or electric plating method plated with copper and/or nickel.Other metal depositions can also adopt, and metal lining has the fusing point higher than scolding tin, thereby form the connection that better heat resistance is arranged than scolding tin.In addition, adopt metal deposition to connect and also avoided forming the possible of low-melting alloy, thereby make the operating chacteristics of fuse more consistent through being welded to connect the scolding tin and the fuse that cause.
As stated, can be on termination electrode and plating belt surface with soldering-tin layer in plating or plating and the wave-soldering covering, with the solderability of assurance electrode.Under the situation that termination electrode and plating belt are for example formed by copper, also can between soldering-tin layer and copper, plate the nickel that one deck shields.
Embodiment 2
Referring to Fig. 5-12, can process a plurality of above-mentioned fuses 1 through two blocks of larger substrate materials are disposable.
Baseplate material can adopt wide material sources and lower-cost single side printed wiring board base material.This base material is coated with one deck Copper Foil on macromolecular material.Certainly, two-sided printed substrate also can use behind the Copper Foil of removing one side.Other surfaces are stained with the thermoplasticity or the heat cured plastics of Copper Foil or other conductive material layer, also are included in the adoptable baseplate material.
Referring to Fig. 5,6, the Copper Foil 10 that adopts the method for electrochemical corrosion or machining will cover on the macromolecular material 11 of baseplate material is processed the termination electrode pattern corresponding with termination electrode.This termination electrode pattern for example can be parallel strip like Fig. 5, shown in 6, also can be other suitable shape as required.After the cutting action of mentioning in the back, this termination electrode pattern will form the termination electrode 300,500,400,600 of each fuse 1.
Referring to Fig. 7,8; Use mechanical means; On baseplate material, process intercommunicating pore 801 arrays like brill, punching press; And use mechanical means in a side (inboard) opposite of baseplate material with above-mentioned termination electrode pattern, as mill, punching press etc. is processed into cavity 901 arrays that are complementary with the intercommunicating pore array, thereby makes the two ends of each cavity 901 be equipped with corresponding intercommunicating pore.The cavity 901 and the intercommunicating pore 801 of space are aligned, and each row of intercommunicating pore 801 arrays are corresponding with each bar of Fig. 5, the parallel strip termination electrode pattern shown in 6.And if adopt other termination electrode pattern, then intercommunicating pore 801 arrays also should be correspondingly corresponding with this termination electrode pattern, thereby make each intercommunicating pore 801 all pass Copper Foil 10.
Certainly, intercommunicating pore 801 arrays of two baseplate materials also can align two baseplate materials disposable the processing in back.
Referring to Fig. 9,10, a side of cavity 901 arrays of a baseplate material is used mechanical means therein, processes the groove 1001 of sunkening cord that is positioned at cavity 901 midline positions as sawing, mill etc.In the groove 1001 of sunkening cord, imbed fuse 1000, fuse 1000 is processed with metal, alloy, composition metal or metal and nonmetal recombination line.
At the inner surface coating binder 1100 of two baseplate materials, scribble adhesive 150 in the contact portion of fuse 1000 and the groove 1001 of sunkening cord, and keep unsettled at cavity 901 part fuses 1000.Fuse 1000 can not receive bending and extruding in installation process.
Referring to Figure 11; After fuse 1000 is bumped into the groove 1001 of sunkening cord; Align two baseplate materials bonding; Make each corresponding intercommunicating pore 801 of two baseplate materials communicate respectively, the corresponding cavity 901,902 of each of two baseplate materials forms cavity 900 respectively, fuse 1000 suspension arrangement in these cavitys 900.
Certainly, the groove 1001 of sunkening cord can be set according to circumstances yet, but fuse 1000 direct folders be established the medial surface that is fixed on two baseplate materials and it is suspended in the cavity 900 through adhesive 1100.
Then with intercommunicating pore 801 inner wall surface activation,, form being electrically connected of termination electrode pattern outside fuse 1000 and two baseplate materials with chemical plating or electric plating method plated with copper and/or nickel.Other metal depositions can also adopt, and metal lining has the fusing point higher than scolding tin, thereby form the connection that better heat resistance is arranged than scolding tin.In addition, adopt metal deposition to connect and also avoided forming the possible of low-melting alloy, thereby make the operating chacteristics of fuse more consistent through being welded to connect the scolding tin and the fuse that cause.
Above-mentioned plating carries out respectively for two baseplate materials after handling and also can on two baseplate materials, processing intercommunicating pore 801 arrays.And then the operations such as bonding that align of fuse 1000 and two baseplate materials are set, thereby form being electrically connected of termination electrode pattern outside fuse 1000 and two baseplate materials.
Similar with the foregoing description 1, can handle on the surface of the coating that the back forms with soldering-tin layer in plating or plating and the wave-soldering covering, with the solderability of assurance electrode at termination electrode pattern and plating.Under the situation that termination electrode pattern and coating are formed by copper, can between soldering-tin layer and copper, plate the nickel that one deck shields.
Like this, processed the array of the fuse 1 of a plurality of unsettled lead-types through two baseplate materials.
At last, referring to Figure 12, this fuse 1 array is carried out horizontal and vertical cutting and forms each single fuse 1 along transverse cut 1200 and vertical line of cut 1300.
In each fuse 1, fuse 1000 can be fixed in the middle of the cavity 900, reduces its rate of heat transfer to periphery, thereby reduces required fusing energy and resistance.In this way, can on two substrates, assemble a plurality of fuses 1 simultaneously.Production efficiency is higher than the conventional method that employing is assembled one by one.
Figure 13 shows the operating chacteristics curve of 1 ampere of 125VAC fuse with fuse structure of the present invention, and Figure 14 shows the operating chacteristics curve of 5 amperes of 125VAC fuses with fuse structure of the present invention.The Fabrication parameter of each parts of two instance fuses is as shown in table 1:
Table 1
Parameter |
1 ampere of 125VAC fuse |
5 amperes of 125VAC fuses |
Upper substrate is thick |
0.7mm |
0.7mm |
Infrabasal plate is thick |
1mm |
1mm |
The intercommunicating pore diameter |
1.2mm |
1.2mm |
Cavity semicircle diameter |
1.2mm |
1.2mm |
The semicircle center of circle, cavity two ends pitch |
2.8mm |
2.8mm |
The electrode copper thickness |
0.035mm |
0.035mm |
The groove depth of sunkening cord |
0.127mm |
0.127mm |
The well width of sunkening cord |
0.3mm |
0.3mm |
Fuse (copper covered steel) line footpath |
0.06mm |
0.1mm |
Average resistance |
0.0736Ω |
0.012Ω |