CN202434327U - PCB (Printed Circuit Board) coil for squirrel-cage tubular current mutual inductor - Google Patents

Abstract

The utility model provides a PCB (Printed Circuit Board) coil for a squirrel-cage tubular current mutual inductor. The PCB coil for the squirrel-cage tubular current mutual inductor comprises a PCB, a pad arranged on the PCB and a printed coil arranged on the PCB. The printed coil is single-layered, double-layered or multi-layered. Adjacent printed coils of adjacent layers are connected electrically through vias. The PCB coil has the advantages of high machining precision, good consistency, high mechanical strength, high reliability and high temperature resistance and the like, and is a main component of the squirrel-cage tubular current mutual inductor.

Description

The pcb board formula coil that is used for the squirrel-cage air-core current transformer

Technical field

The utility model relates to a kind of pcb board formula coil that is used for the squirrel-cage air-core current transformer.This pcb board formula coil is a kind of coil based on the PCB printed conductor, can be individual layer, bilayer or multi-layer PCB structure.Squirrel-cage air-core current transformer wherein is based on electromagnetic induction principle and a current measurement instrument transformer that designs; Measuring range is wide, measurement electric current big (from several amperes to hundreds thousand of amperes), is mainly used in the measurement of the short net of high-power smelting equipment such as the hot stove in (but being not limited to) ore deposit, converter electric current.

Background technology

The soft Luo-coil of available technology adopting has been shown among Fig. 1; It is that enamelled wire is wound on the skeleton of soft nonmagnetic substance; Let high-current conductor to be measured pass its geometric center and carry out current measurement; Because do not comprise magnetic core, do not have the magnetic saturation problem, so measuring range is wide, the linearity is good.Processing with use in require loop density constant (axial distribution is even), coil section is long-pending and shape is consistent, coil section is vertical with center line as far as possible.Owing to be soft coil, have very strong construction convenience, therefore extensively adopted.

But, many shortcomings below the soft Luo-coil among Fig. 1 also exists:

When producing Luo-coil, as adopt craft or semi-hand technique for coiling, be difficult to guarantee that the sectional area of coiling is identical and along the uniformity of skeleton axial distribution, this will bring measure error;

When adopting high-precision numerical control winding apparatus to reel, can guarantee the accuracy of winding process itself preferably, but soft skeleton easy deformation, the coil section shape of twining on it changes easily, and this causes measure error;

Be easy to generate wriggling between coil and skeleton, the tractive and the bending of coil can cause the coil relative position to change in installing and the use, have destroyed uniform coil distribution property, and this has increased measure error;

Mechanical strength is low, and in installing and the use, extruding can cause coil section even coil rack distortion, usually causes permanent deformation even damage, and this increases measure error and has reduced reliability;

Soft skeleton and outer layer protection are relatively poor with the temperature characterisitic of soft rubber, easy ageing, and sensor reliability reduces; Coil section is little, and induced electricity forces down, output signal a little less than, anti-electromagnetic interference capability is poor;

Opening is bigger, causes coil distribution uneven, exists systematic eccentric error to realize the technological means relative complex of electromagnetic shielding; Coil almost can't be repaired after damaging, and application cost is high, and processing request is high, and production cost is high.

In addition, also have a kind of hard PCB formula coil in the prior art, it adopts two-sided PCB based on method for designing and the accurate processing technology of PCB, and the wiring on the two sides is connected in series with via hole, thereby generates the equivalent coil based on printed conductor.As shown in Figure 2, solid line and dotted line are represented top layer and the bottom of PCB respectively among the figure.

Hard PCB formula coil has been abandoned many inherent defects of soft Luo-coil on the basis that has kept the essential advantage that soft Luo-coil measuring range is wide, height is linear, be applied in some occasions.But still there is following weak point in it:

The thickness deviation of same batch PCB base material seldom can accomplish below 1%, and is high even can reach 10%; In uneven thickness with a slice PCB; There is discreteness in the PCB thickness of different batches; More than three kinds of in esse situations cause coil section long-pending inequality, the mutual inductance parameter is inconsistent, accurately measuring must be to different that individual coil is carried out the systematicness adjustment or the demarcation of otherness;

The PCB base material is acted upon by temperature changes and shows that mainly base material thickness changes, and this causes the mutual inductance parameter to change equally;

Need high-density wiring in order to increase coil turn, so the quantity of PCB via hole is big, via size is little, this has increased the failure rate of transducer; Same problem because of number of vias and via size, this structure is difficult to realize multiple-plate application;

Receive the influence of wire pitch, there is the non-uniform phenomenon of opening part loop density in the application of pincerlike connecting method, influences certainty of measurement;

Receive the influence of sheet metal thickness, the area of single turn necklace is difficult to do greatly, is unfavorable for improving the sensitivity of measurement;

Electric or mechanical damage causes scrapping of whole sensor easily, and the technical difficulty of maintenance is higher.

In sum, be necessary to develop a kind of novel current transformer and the pcb board formula coil that is used for the squirrel-cage air-core current transformer, overcome the said problem that exists in the prior art.

The utility model content

In order to overcome at least one deficiency or defective in the prior art, a purpose of the utility model provides a kind of pcb board formula coil that is used for the squirrel-cage air-core current transformer.Particularly; Realize through following technical scheme: a kind of pcb board formula coil that is used for the squirrel-cage air-core current transformer; It is characterized in that comprising pcb board, be arranged on the pad on the pcb board and be arranged on the printed coil on the pcb board, wherein said printed coil is an individual layer; Perhaps said printed coil is two-layer or multilayer more, and the printed coil of adjacent layer is electrically connected through via hole.

According to the utility model on the other hand, said printed coil is round rectangle coil, circular coil, oval coil or involute shape coil.

The utility model compared with prior art has one or more following advantage:

The loop density that density unevenness when having abandoned soft Luo-coil coiling has caused when having spared, having avoided coil and skeleton to produce wriggling is inhomogeneous, has overcome that coil is pulled or pushes the distortion that causes, the distortion of having avoided non magnetic skeleton causes the long-pending variation of coil section;

The via hole of PCB has only one, and mechanical strength is higher, reliability is more guaranteed, and variations in temperature is littler to the influence of the actual induction area of coil, and can adopt the multi-layer PCB structure easily, realizes the adjusting on a large scale of coefficient of mutual inductance (or sensitivity);

Number of plies of the density of the shape of the size of regulating winding, coil, coil, coil etc. easily; The error that exists opening to introduce hardly under the semicircle splicing application mode, certainty of measurement height, stable performance, life-span be long, be easy to safeguard, cost is low, be fit to batch process.

Description of drawings

Fig. 1 is the structural principle sketch map of a kind of soft Luo-coil of the prior art.

Fig. 2 is the structural representation of a kind of hard PCB formula coil of the prior art.

Fig. 3 is a kind of squirrel-cage air-core current transformer sketch map according to the utility model preferred embodiment.

Fig. 4 is the another kind of squirrel-cage air-core current transformer sketch map according to the utility model preferred embodiment.

Fig. 5 is a kind of pcb board formula technical front sketch map according to the squirrel-cage air-core current transformer of the utility model preferred embodiment.

Fig. 6 is a kind of pcb board formula coil schematic rear view (perspective) according to the squirrel-cage air-core current transformer of the utility model preferred embodiment.

Embodiment

Below in conjunction with accompanying drawing; The preferred forms of the utility model is described through preferred embodiment; The embodiment here is at length to explain the utility model, and should not be construed as the restriction to the utility model, under the situation of spirit that does not break away from the utility model and essential scope; Can make various distortion and modification, these all should be included within the protection range of the utility model.

The squirrel-cage air-core current transformer adopts based on the method for designing of PCB and accurate processing technology, with the PCB welding one of the different functions of multi-disc, forms the electric current detecting coil of an equivalence.

Referring to Fig. 3; Wherein show a kind of squirrel-cage air-core current transformer; Comprise the upper strata arc pcb board 2 and lower floor's arc pcb board 3 and a plurality of compartment of terrain along the circumferential direction and equally distributed pcb board formula coil 1 that laterally arrange; Wherein, said pcb board formula coil 1 is arranged between said upper strata arc pcb board 2 and the lower floor's arc pcb board 3, and vertical with lower floor arc pcb board 3 with said upper strata arc pcb board 2; The top and bottom of pcb board formula coil 1 are fixedly connected with lower floor arc pcb board 3 with said upper strata arc pcb board 2 respectively, and wherein said a plurality of pcb board formula coils 1 electrically are connected in series through said upper strata arc pcb board 2 or lower floor's arc pcb board 3.

Preferably, referring to Fig. 5-6, said pcb board formula coil 1 is rectangular pcb board formula coil.

Preferably, said pcb board formula coil 1 comprises a plurality of round rectangle coils 6, circular coil, oval coil or the involute shape coil that is provided with on the pcb board.Alternatively, pcb board formula coil 1 can adopt two-sided PCB structure, also can adopt the multi-layer PCB structure.Coil shape can be the round rectangle among the figure, also can be various ways such as circle, ellipse, involute property, and the shape and size of coil and the line of printed conductor footpath all can be regulated, thereby have great flexibility.

Preferably, said pcb board formula coil 1 comprises two-layer or lattice coil 6 more.Printed conductor (coil) two-layer or multilayer for example links to each other through the via hole 5 of middle upside among the figure, forms the complete coil that two pads 4 with pcb board formula coil 1 upper end are drawn end points.Two pads 4 of pcb board formula coil 1 lower end only fix or locate usefulness, and when otherwise realizing the location, it also can omit.

Preferably, said pcb board formula coil 1 comprises the pad 4 that is used to be electrically connected said upper strata arc pcb board 2 and lower floor's arc pcb board 3.

Preferably, said pcb board formula coil 1 comprises the via hole 5 that is used to be electrically connected two-layer or lattice coil 6 on this pcb board formula coil.

Preferably, referring to Fig. 4, said upper strata arc pcb board 2 is the semi-round ring shape pcb board with lower floor's arc pcb board 3.Shown in Fig. 4 is the two semicircular structure instrument transformers of a kind of opening mode, and two semi-round ring shape structural parameters are identical, all comprise up and down two be used to connect and fixing semi-round ring shape PCB and some along the equally distributed pcb board formula of semi-circumference coil.During use two members are stuck on the carrying object to be detected, with miniature connector two are carried out seamless splicedly, form a complete coil, signal is drawn from preset coil end.This structure is applicable to the directly carrying object current detecting occasion of suit of inconvenience.

Preferably, referring to Fig. 3, said upper strata arc pcb board 2 is the annular pcb board with lower floor's arc pcb board 3.Closed circular shown in Fig. 3 annular structure instrument transformer, comprise up and down two and be used to connect/fixedly usefulness annular PCB with several along the equally distributed PCB formula of circumference coil, signal is drawn from the coil end of presetting.This structure is applicable to the carrying object current detecting occasion of convenient direct suit.

Preferably, said pcb board formula coil 1 can comprise pcb board 1, is arranged on the pad 4 on the pcb board 1 and is arranged on the printed coil 6 on the pcb board 1 that wherein said printed coil 6 is an individual layer; Perhaps said printed coil 6 is two-layer or multilayer more, and the printed coil 6 of adjacent layer is electrically connected through via hole 5.It is understandable that for example when printed coil 6 was multilayer, the via hole 5 between the printed coil of an adjacent layer and another via hole 5 between another adjacent layer can be overlapping, also can misplace.Said printed coil 6 can be round rectangle coil, circular coil, oval coil or involute shape coil or the like.Referring to Fig. 3-4, the direction that the upper end of this pcb board formula coil 1, lower end are fixed is all overlapping with the radial direction of annular/semi-round ring shape pcb board.

The utility model compared with prior art has one or more following advantage:

The loop density that density unevenness when this design has been abandoned soft Luo-coil coiling has caused when having spared, having avoided coil and skeleton to produce wriggling is inhomogeneous, has overcome that coil is pulled or pushes the distortion that causes, the distortion of having avoided non magnetic skeleton causes the long-pending variation of coil section;

This design is compared with PCB formula coil shown in Figure 2; The via hole of PCB has only one; Mechanical strength is higher, reliability is more guaranteed; Variations in temperature is littler to the influence of the actual induction area of coil, and can adopt the multi-layer PCB structure easily, realizes the adjusting on a large scale of coefficient of mutual inductance (or sensitivity);

This design is the size, the shape of coil, the density of coil, the number of plies of coil etc. of regulating winding easily; The error that exists opening to introduce hardly under the semicircle splicing application mode, certainty of measurement height, stable performance, life-span be long, be easy to safeguard, cost is low, be fit to batch process.

The above only is the preferred embodiment of the utility model, be not the utility model is done any pro forma restriction, though the utility model disclose as above with preferred embodiment, yet be not in order to limit the utility model.Those of ordinary skills, in not breaking away from the utility model technical scheme scope, the technology contents of above-mentioned announcement capable of using is made amendment and is changed.It is pointed out that technical spirit according to the utility model to any simple modification, equivalent variations and modification that above embodiment did, all still belongs in the scope of the utility model technical scheme.The protection range of the utility model is defined by the following claims.

Claims (2)

1. a pcb board formula coil that is used for the squirrel-cage air-core current transformer is characterized in that comprising pcb board, is arranged on the pad on the pcb board and is arranged on the printed coil on the pcb board, and wherein said printed coil is an individual layer; Perhaps said printed coil is two-layer or multilayer more, and the printed coil of adjacent layer is electrically connected through via hole.

2. the pcb board formula coil that is used for the squirrel-cage air-core current transformer according to claim 1 is characterized in that, said printed coil is round rectangle coil, circular coil, oval coil or involute shape coil.

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