CN114188129A

CN114188129A - Transformer and preparation method thereof

Info

Publication number: CN114188129A
Application number: CN202111368699.3A
Authority: CN
Inventors: 李炎; 马涛; 唐林江; 隋淞印; 彭聪辉; 陈广军; 孙宇; 刘金娥; 张明华; 陈雅容; 张彬彬; 王宁宁
Original assignee: Beijing Satellite Manufacturing Factory Co Ltd
Current assignee: Beijing Satellite Manufacturing Factory Co Ltd
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2022-03-15
Also published as: WO2023087838A1

Abstract

The invention relates to a transformer and a preparation method thereof, wherein the transformer comprises a frame body (1), a line type winding (2) and a magnetic core (3), the frame body (1) comprises a supporting frame (11) and a base (12), the line type winding (2) is wound on the supporting frame (11), and the transformer further comprises a sheet type winding (4), and the sheet type winding (4) is sleeved on the outer side of the line type winding (2). The invention can improve the efficiency and space utilization rate of the power supply product.

Description

Transformer and preparation method thereof

Technical Field

The invention relates to a transformer and a preparation method thereof.

Background

With the development of aerospace industry, the output requirement of load equipment on aerospace secondary power supplies in aerospace satellite and commercial satellite projects reaches 5V/20A, the efficiency requirement is up to 88%, and power supply products are further required to develop towards miniaturization. The existing power supply products mainly comprise a thick film power supply and an aerospace low-voltage large-current secondary power supply. And although thick film power supply products are small in size, the efficiency is only about 79%, and therefore the power density and the efficiency cannot meet the task requirements. Although the efficiency of the semi-synchronous rectification power supply of the aerospace low-voltage large-current secondary power supply is high (up to 85%), the aerospace low-voltage large-current secondary power supply has a large volume and cannot meet the requirement of small volume. It can be seen that from the state of the art of modular power supplies, both operating efficiency, power density and reliability are placing higher demands. In this regard, some techniques attempt to provide the power supply with a transformer to increase its power density of use. The general transformer is a plug-in transformer, so that a large amount of wiring space on the front and back surfaces of a circuit board can be occupied after the transformer is installed, and the end of a secondary enameled wire is required to be subjected to depainting, tin coating and wiring, so that the safety distance of a printed circuit board line is seriously influenced, namely the situation that the installation and connection polarity judgment is difficult exists. Moreover, the height of such transformers is much greater than other components inside the power supply, thereby reducing the power density of the power supply module.

Of course, some surface mount transformers exist in the prior art, but these transformers usually use a simple coil as a winding, and thus cannot well meet the requirement of large current. In addition, the surface-mounted transformer applied to the aerospace field is easy to lose effectiveness, and the main influencing factors comprise the physical performance of the framework, the layout of a printed circuit board assembly part, the design of a welding pad, the welding of an enameled wire and the like. Therefore, from the process point of view, if the selection of the assembly process parameters and the like is not proper, the vibration resistance of the product can be seriously weakened, and the poor phenomena of pin fracture, welding point damage, magnetic core glue failure and the like are easily generated in the process of research or environmental test of the device, so that the reliability of the whole power supply product is further influenced. Therefore, how to design a miniaturized surface-mounted transformer for a module power supply to meet the application requirement of a spacecraft becomes an urgent problem to be solved.

Disclosure of Invention

The invention aims to provide a transformer and a preparation method thereof.

In order to achieve the purpose, the invention provides a transformer and a preparation method thereof, the transformer comprises a frame body, a line type winding and a magnetic core, wherein the frame body comprises a supporting frame and a base, the line type winding is wound on the supporting frame, and the transformer further comprises a sheet type winding, and the sheet type winding is sleeved on the outer side of the line type winding.

According to one aspect of the invention, the sheet type winding is plate-shaped, the middle part of the sheet type winding is bent to form a rectangular cylinder with three side surfaces, and two ends of the sheet type winding are provided with welding feet;

the sheet winding is made of a red copper sheet, the thickness of the red copper sheet is 0.1-0.3 mm, and the surface of the red copper sheet is subjected to nickel plating treatment;

the length, the width and the height of the sheet type winding are respectively 3.6mm multiplied by 2mm multiplied by 4.9mm, and the length of the welding leg is 1.1-1.3 mm.

According to one aspect of the invention, the magnetic core is formed by bonding two core bodies, and the bonding glue is modified epoxy resin with the shear strength (room temperature)/MPa being more than or equal to 25 and the 90-degree plate peeling strength/N/cm being more than or equal to 25;

the core body opposite side is provided with connecting bulges which are arranged at intervals, the two core bodies are connected through the connecting bulges, and the middle connecting bulge is positioned on the inner side of the supporting frame.

According to one aspect of the invention, two rows of pin terminals which are arranged alternately are arranged on two sides of the base respectively, and the pin terminal interval on each side is 1.8-1.9 mm;

the pin terminal is made of phosphor bronze, and a nickel layer with the thickness of 1.2-1.3 um and a tin layer with the thickness of 4.5-5.5 um are plated on the surface of the pin terminal;

the length, width and height of the frame body are respectively 11.5mm multiplied by 10.9mm multiplied by 4.7 mm;

the end parts of the wire windings are fixedly welded with the pin terminals, and the solder is 63Sn37Pb solder wire.

According to one aspect of the invention, the magnetic core further comprises a clamp spring clamped on the outer side of the magnetic core.

According to one aspect of the invention, the device comprises three linear windings respectively wound on the supporting frame, wherein two turns of linear windings positioned at the innermost side and the outermost side are primary windings, and one turn of linear winding positioned in the middle is secondary windings;

insulating adhesive tapes are arranged among the wire type windings wound adjacently, among the sheet type windings and the wire type windings and on the sheet type windings, and two layers of insulating films with the thickness of 0.02-0.03 mm are arranged among the wire type windings wound adjacently;

the wire winding is an enameled wire consisting of a round copper wire and a double-layer polyimide thick insulating paint film wrapped on the outer side of the round copper wire;

the insulating tape and the insulating film are both made of polyimide;

the frame body is made of phenolic polyester.

According to one aspect of the invention, the transformer is provided with insulating paint, and the insulating paint is epoxy ester drying insulating paint formed by mixing epoxy resin, dry vegetable oil acid, amino resin, xylene and butanol.

A method for making a transformer, comprising the steps of:

a. winding the wire winding on the supporting frame;

b. the tail end of the wire winding is subjected to paint removal treatment and then is fixed on a pin terminal;

c. sleeving the sheet type winding outside the online winding;

d. and bonding the two core bodies to form a magnetic core, and clamping the clamp spring outside the magnetic core.

According to one aspect of the invention, in the step (a), three wire windings of the primary and the secondary are wound in a staggered manner, and one layer of insulating tape and two layers of insulating films are arranged for each wound wire winding;

in the step (b), after the three linear windings are wound, removing paint from the two linear windings, reserving a paint coating on the other linear winding, dividing the end parts of the three linear windings into two strands respectively, and winding the two strands on the pin terminal by one turn respectively along different clockwise directions;

in the step (c), firstly, insulating tapes are arranged on the wire winding and the sheet winding on the outermost side, and then the sheet winding is sleeved outside the wire winding;

in the step (d), the surface of the core body is cleaned and dried by using an absolute ethyl alcohol cotton ball, then the prepared bonding glue is uniformly coated on the bonding surface of the core body, and then the core body is bonded and assembled on the frame body to form the magnetic core.

According to an aspect of the invention, further comprising:

e. dipping paint on the transformer;

f. carrying out high and low temperature environment test and electrical property test on the transformer;

the step (e) comprises pre-baking, paint liquid preparation, vacuumizing and paint dipping, paint dripping, drying and cooling;

the pre-drying is to heat the transformer in an oven at the temperature of 70-90 ℃ for 5-7 h;

the paint liquid is prepared by uniformly mixing insulating paint and dimethylbenzene, pouring into a viscometer, and completely dripping the viscometer within 20-30 s at the temperature of 20-25 ℃;

the vacuum pumping and paint dipping comprises the steps of immersing a preheated transformer in paint liquid, then putting the transformer into a vacuum tank, pumping the transformer to 0.08-0.12 Mpa, keeping the transformer for 15-25 min, then removing the vacuum, keeping the transformer at normal pressure for 10-20 min, and then cleaning the transformer;

the paint dripping is that the transformer is placed indoors for not less than 14 hours;

the drying is that the transformers are mutually separated and lead-out wires are arranged, then the transformers are placed in the oven, and the distance between the transformers and the wall of the oven is not less than 80mm when the transformers are stacked;

after the transformer is cooled, checking the brightness degree of the surface of the transformer, the condition of existence of air bubbles and the condition of existence of paint accumulation at the end part of the outgoing line;

the high-low temperature environment test is completed at the temperature of-55-100 ℃;

the electrical property test comprises the steps of testing inductance, Q value, leakage inductance, direct current resistance, insulation resistance and medium withstand voltage of the transformer by using an LCR bridge, an insulation resistance meter, a withstand voltage tester and microohm meter equipment.

According to the invention, the aerospace surface-mounted transformer can be suitable for aerospace low-power supply modules (1W-50W), medium-power supply modules (50W-200W) and other spacecraft power supply products with high requirements on service life and reliability, and can also be applied to power supply products with miniaturization requirements in a ground environment. In addition, the transformer structure is improved, so that the problem of large volume of the magnetic ring is solved, the occupied area of the circuit board is small, and the utilization rate of the internal space is high. According to the concept of the invention, the transformer can be enabled to switch on larger current by combining the wire winding and the sheet winding.

According to one scheme of the invention, the sandwich winding and clamping winding processing method of the primary winding and the secondary winding is adopted, so that the leakage inductance problem of the aerospace surface-mounted transformer can be reduced, and the voltage pressure of the power switch tube can be reduced, thereby reducing an absorption circuit and indirectly improving the efficiency of a power supply. In addition, the invention also adopts a winding method with uniform return wire, which can solve the problem of interference between the magnetic core and the wire winding and more efficiently utilize the winding space of the frame body.

According to one scheme of the invention, a 2-turn tin-coating + 1-turn tin-coating-free end head processing method is adopted, namely, one turn of the three-turn winding is provided with the original paint coating, so that the strength of the terminal can be enhanced. And a single-column bidirectional parallel winding method is adopted during winding, so that the number of winding turns can be reduced, the height of welding points is reduced, and the risks of interference and short circuit among terminals, between the terminals and the clamp spring are solved.

According to one scheme of the invention, the transformer has higher pressure resistance and firmness by adopting the paint dipping method, and the paint dipping under vacuum can remove air in gaps of workpieces so as to enhance the fluidity, permeability and filling performance of paint liquid, and can quickly soak into all gaps of the transformer without gaps and leakage so as to achieve the aim of more compact soaking, so that the transformer has higher insulating performance and mechanical strength.

Drawings

FIG. 1 schematically illustrates a disassembled view of a transformer in accordance with an embodiment of the present invention;

FIG. 2 schematically illustrates an isometric view of a transformer in accordance with an embodiment of the present invention;

FIG. 3 schematically illustrates a front view of a transformer according to an embodiment of the present invention;

FIG. 4 is a cross-sectional view taken along line E-E of FIG. 3;

FIG. 5 schematically illustrates a side view of a transformer according to an embodiment of the present invention;

FIG. 6 is a sectional view taken in the direction F-F in FIG. 5;

FIG. 7 schematically illustrates an isometric view of a sheet winding in a transformer in accordance with an embodiment of the present invention;

FIG. 8 schematically illustrates a partial flow diagram of a method of making a transformer in accordance with an embodiment of the present invention;

FIG. 9 schematically shows an overall flow chart of a method of manufacturing a transformer according to an embodiment of the present invention;

fig. 10 schematically shows a transformer according to an embodiment of the present invention applied to a power printed board assembly.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.

The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.

Referring to fig. 1 to 6, the (aerospace surface-mount) transformer of the present invention may be applied to the field of electronic assembly, and includes a frame body 1, a wire winding 2 and a magnetic core 3, where the frame body 1 includes a supporting frame 11 and a base 12, and the wire winding 2 is wound on the supporting frame 11. In the invention, the transformer is also provided with a sheet type winding 4, and the sheet type winding 4 is sleeved outside the linear type winding 2. Thus, the transformer of the present invention is equivalent to four layers of windings, and one of the wire windings 2 is replaced by the sheet winding 4, so that higher current can be switched. Of course, too many sheet-type windings 4 are not good for insulation, and therefore only one sheet of sheet-type winding 4 may be provided.

As can be seen from fig. 7, in the present invention, the sheet winding 4 is plate-shaped, the middle portion of the plate winding is bent to form a rectangular tube with three sides, and two ends of the plate winding are provided with solder tails 41. In this way, the sheet-type winding 4 as a whole (i.e. together with the solder leg 41) forms a "zigzag", and the height of the solder leg 41 is adapted to the pin on the base 12, so that a surface-mount connection can also be realized. The sheet winding 4 is made of a red copper sheet, and the thickness of the red copper sheet is 0.1-0.3 mm. And, the surface of the sheet type winding 4 should be plated with nickel, so that the surface is smooth and has no burrs, and the subsequent welding can be smoothly carried out. The length, width and height of the sheet winding 4 are respectively 3.6mm multiplied by 2mm multiplied by 4.9mm, and the length of the welding leg 41 is 1.1-1.3 mm. So, the whole length of piece formula winding 4 together with leg 41 is 5.8 ~ 6.2mm to can match support body 1 behind the coiling line formula winding 2.

With continued reference to fig. 1, in the present invention, the magnetic core 3 is formed by bonding two

core bodies

31,32, the bonding glue is a modified epoxy resin with a shear strength (room temperature)/MPa of not less than 25 and a 90 ° plate peel strength/N/cm of not less than 25, and the material has good toughness and durability. The opposite sides of the

core bodies

31,32 are provided with connecting protrusions a arranged alternately, the two

core bodies

31,32 are connected by the connecting protrusions a, and the middle connecting protrusion a is positioned at the inner side of the supporting frame 11. Naturally, in order to reinforce the bonded magnetic core 3, the invention further provides a clamp spring 5, as shown in fig. 2, and when the magnetic core is installed, the clamp spring 5 is clamped on the outer side of the magnetic core 3.

The frame body 1 is made of phenolic polyester (namely bakelite) and can resist the high temperature of 400 ℃. Two sides of the base 12 are respectively provided with a row of pin terminals 12a arranged alternately, and the distance between the pin terminals 12a on each side is 1.8-1.9 mm. The pin terminal 12a is made of phosphor bronze, and has a nickel layer with a thickness of 1.2 to 1.3um and a tin layer with a thickness of 4.5 to 5.5um plated (electroplated) on the surface. Thus, the length, width and height of the entire frame body 1 are 11.5mm × 10.9mm × 4.7mm, respectively. The end part of the wire winding 2 is welded and fixed with the pin terminal 12a, and the solder at the welding point is 63Sn37Pb solder wire with aerospace level phi 0.8-0.82 mm.

In the present embodiment, the transformer includes three wire windings 2 wound around the support frame 11. The two turns of linear winding 2 positioned at the innermost side and the outermost side are primary windings, the one turn of linear winding 2 positioned in the middle is a secondary winding, the primary windings and the secondary windings are not essentially different in structure, and only the input and the output realize the voltage transformation function through the difference of the winding turns. In the invention, insulating tapes are arranged between the adjacent wound wire windings 2, between the sheet type winding 4 and the wire winding 2 and on the sheet type winding 4, and two layers of insulating films with the thickness of 0.02-0.03 mm are arranged between the adjacent wound wire windings 2. The wire winding 2 is an enameled wire consisting of a round copper wire and double layers of polyimide thick paint film insulating paint wrapped on the outer side of the round copper wire, and can resist the high temperature of 220 ℃. Moreover, the insulating tape and the insulating film are made of polyimide (namely polyimide pressure sensitive tape and polyimide film), and the material has the characteristics of no toxicity, high temperature resistance (reaching 220 ℃), extremely high thermal stability, extremely low temperature resistance (no brittle fracture in liquid helium at-269 ℃), high irradiation resistance and good insulating property, and can be perfectly suitable for insulation between the windings and the magnetic core 3.

The transformer also has insulating paint, the insulating paint is epoxy ester drying insulating paint prepared by mixing epoxy resin, dry vegetable oleic acid, amino resin, xylene and butanol, has excellent heat resistance and adhesive force, has better oil resistance and flexibility, can be suitable for a damp and hot environment, and has good corrosion resistance, moisture resistance and insulating effect on devices.

As shown in fig. 8 and 9, the method for manufacturing a transformer of the present invention first requires the frame body 1, the wire winding 2 (enameled wire), the magnetic core 3, the sheet winding 4, and the jump ring 5 to be inspected, thereby ensuring that all components are defect-free. Then, the winding operation can be performed, specifically, the frame body 1 is fixed on the winding machine through the tool, the pin direction is observed, then the wire winding 2 is wound on the supporting frame 11 through the winding auxiliary tool, and corresponding insulation treatment (namely, winding of an insulating tape and an insulating film) should be performed every time one turn is wound. Subsequently, the end of the wire winding 2 is subjected to a paint removal process and then fixed to the pin terminal 12 a. In the invention, uniform wiring is adopted during winding, and three primary and secondary linear windings 2 are wound in a staggered manner in a sandwich winding and clamping manner to form a winding structure of the primary linear winding 2 and the secondary linear winding 2, so that staggered winding of different windings on each layer is realized. In addition, when the winding end part is processed, the mode of processing one by one is not adopted, and the three wire-type windings 2 are uniformly processed after being wound, namely, the return wires are uniform. In this way, the winding bulge phenomenon occurring when the positions of the pin terminals 12a corresponding to the wire winding 2 are staggered can be avoided, so that the coupling can be increased, and the leakage inductance and the peak can be reduced.

After the wire winding 2 is wound in the above manner, an insulating tape matched with the width of the frame body 1 needs to be arranged on the wire winding 2 at the outermost side, and specifically, the wire winding 2 can be wound for two circles to form insulation. And then paint removal treatment can be carried out at the starting end and the tail end of the wound wire winding 2. Specifically, in the embodiment, only two wire windings 2 in three turns are subjected to paint removal treatment (i.e., the insulating layer is removed), and the other wire winding is kept with the original paint skin, i.e., 2 turns of tin coating and 1 turn of tin coating are not carried out, so that the terminal strength can be enhanced. And tin coating treatment is carried out on the paint removing part, and the length of the part is 3-5 mm.

After depainting, the end parts of the three wire windings 2 are respectively divided into two strands (the wire winding 2 can be understood as a double-wire structure), the two strands are wound on the pin terminal 12a in a double-fold mode along different hour-hand directions for one turn (namely 1N), and then a 5-series soldering iron is used for carrying out spot welding by using 63Sn37Pb soldering wires, so that the wire winding 2 can be fixed on the pin terminal 12 a. For example, in the start-end process, the end of the wire winding 2 can be directly placed on the corresponding pin terminal 12a, so that two strands of single wires are wound on the pin terminal 12a by one turn clockwise and counterclockwise, respectively, and thus this manner can be referred to as single-pole bidirectional winding, and three pin terminals 12a on each side correspond to three turns of the wire winding 2. Compared with the method of normally winding two turns, the method reduces one turn, thereby reducing the height of welding spots and increasing the safety distance between the pin terminals 12a and the clamp spring 5.

After the wire winding 2 is arranged, the sheet winding 4 is sleeved outside the wire winding 2. Of course, insulation treatment is also required between the sheet type winding 4 and the magnetic core 3. Therefore, the present invention also winds a polyimide pressure sensitive adhesive tape around the portion of the sheet type winding 4 contacting the magnetic core 3, and then mounts it on the frame body 1.

Then, the magnetic core 3 can be mounted, specifically, the surfaces of the

core bodies

31 and 32 are cleaned and dried by using an absolute ethyl alcohol cotton ball, and then whether the magnetic cores are matched or not is checked. Then, a modified epoxy resin adhesive is prepared and applied to the bonding surfaces of the two

core bodies

31 and 32. When the adhesive is applied, the adhesive is uniformly applied by using a scraping mode of a scraping blade, and then the two

core bodies

31 and 32 penetrate into the support frame 11 after winding, and the two

core bodies

31 and 32 can be adjusted to align the bonding surfaces in the process. The external tooling should then be pressed until the primary inductance is exceeded, so that the two

cores

31,32 are glued in the frame 1 to form the magnetic core 3. And finally, clamping the clamp spring 5 outside the magnetic core 3 to reinforce the magnetic core, so that the assembly of the magnetic core 3 and the bonding and curing of the adhesive are completed. Of course, after the assembly is completed, the corresponding product mark can be arranged on the clamp spring 5.

After the steps are completed, the transformer is dipped in paint in a vacuum environment, and the method comprises the steps of pre-drying, paint liquid preparation, vacuumizing and paint dipping, paint dripping, drying and cooling. In the pre-drying process, the transformer is firstly placed in an oven to be heated, the heating temperature is 70-90 ℃, and the temperature is kept for 5-7 hours. When preparing the paint liquid, the epoxy resin drying insulating paint is poured into a container, and a small amount of dimethylbenzene is poured into the container to be uniformly stirred. At this point, the bottom of the viscometer is first blocked and the paint is poured into it until it is full. The viscometer bottom should then be undone and timed using a stopwatch. The process is required to be completed at the room temperature of 20-25 ℃, and the time for completing the dropping of the viscometer is ensured to be between 20s and 30s, which can be specifically seen in the following table 1:

room temperature/. degree.C	20	21	22	23	24	25
							time/S	30	28	26	24	22	20

TABLE 1 preparation of lacquer liquid

Of course, the tolerance of ± 1s is allowed when the paint liquid is prepared, and if the prepared paint liquid cannot meet the requirement, the steps are repeated until the requirement is met. After the preparation of the paint liquid is finished, the paint liquid can be used for the subsequent paint dipping process.

When the vacuum pumping and paint dipping are carried out, the preheated transformer is immediately placed into a container with the mixed paint, the paint surface is higher than the transformer, then the transformer and the transformer are placed into a vacuum tank together to start vacuum pumping, the vacuum is released after the head pointer on the vacuum tank points to 0.08-0.12 Mpa, and the vacuum is kept for 15-25 min and kept for 10-20 min under normal pressure. The transformer can then be cleaned to remove excess insulating varnish.

And in the paint dripping process, the transformer soaked with the paint is placed indoors for paint dripping, and the process is not less than 14 hours. And then, drying can be carried out, the transformers are mutually separated before drying, and the outgoing lines are arranged so that the outgoing lines are not overlapped. And then the transformer is placed in the oven, and the distance between the stacking position and the oven wall is not less than 80 mm. And cooling the transformer after drying, wherein the surface of the transformer after paint dipping is detected to be bright and free of air bubbles, and no paint is accumulated at the end part of the outgoing line.

Therefore, the vacuum paint dipping operation can be completed, and the transformer has higher pressure resistance and firmness. And the vacuum mode is adopted in the dipping paint, so that the air in the gaps of the workpieces can be removed, the fluidity, the permeability and the filling performance of the paint are enhanced, the paint liquid permeates into each gap in the transformer, the dipping paint is ensured to be dense, and the transformer has higher insulating performance and mechanical strength.

After the vacuum painting of the whole transformer is completed as described above, the preparation of the transformer is basically completed, and then a series of detection works can be performed on the transformer. Specifically, the invention performs high and low temperature environment test and electrical property test on the transformer. The high-low temperature environment test is completed under high-low temperature circulation at minus 55-100 ℃, and the electrical property test comprises the steps of testing the inductance, the Q value, the leakage inductance, the direct current resistance, the insulation resistance and the medium voltage resistance of the transformer by using an LCR bridge, an insulation resistance meter, a voltage-resistant tester and microohm meter equipment, so that the transformer can meet various index requirements.

As shown in fig. 10, the invention reduces the size and weight of the transformer at the heavy current output end of the module power supply, thereby indirectly realizing the miniaturization of the power module product, achieving the design target of the size of the power supply product equivalent to the load, and improving the efficiency of the power supply module. In addition, the transformer adopts surface-mounted design (including pins and sheet windings) to the greatest extent, so that the reliability and the production efficiency of the transformer product are improved. In addition, the invention also adopts means such as optimized winding, pin terminal welding, vacuum paint dipping and the like, so that the transformer can resist severe environment conditions such as high and low temperature alternation, thermal vacuum, vibration, impact and the like, and effectively improves various performances of the transformer in severe environment resistance, thereby meeting the requirement of long-time use in severe environment of space navigation, being suitable for all batched, standardized and surface-mounted space navigation DC/DC power supplies and meeting the application in circuit products with high requirements on vibration resistance. In conclusion, the method for preparing the transformer has the advantages that the reliability of the assembling mode is high, the production efficiency can be improved by 7%, and the volume of the transformer is relatively reduced by 50%.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a transformer, includes support body (1), line formula winding (2) and magnetic core (3), support body (1) is including supporting frame (11) and base (12), line formula winding (2) coiling is in on supporting frame (11), its characterized in that still includes piece formula winding (4), piece formula winding (4) cover is established the outside of line formula winding (2).

2. The transformer according to claim 1, characterized in that the sheet winding (4) is plate-shaped, the middle part of which is bent to form a rectangular cylinder with three sides, and two ends of which are provided with welding feet (41);

the sheet winding (4) is made of a red copper sheet, the thickness of the red copper sheet is 0.1-0.3 mm, and the surface of the red copper sheet is subjected to nickel plating treatment;

the length, the width and the height of the sheet type winding (4) are respectively 3.6mm multiplied by 2mm multiplied by 4.9mm, and the length of the welding leg (41) is 1.1-1.3 mm.

3. The transformer according to claim 1, characterized in that the magnetic core (3) is formed by bonding two core bodies (31,32), the bonding glue is a modified epoxy resin with a shear strength (room temperature)/MPa of more than or equal to 25 and a 90 ° sheet peel strength/N/cm of more than or equal to 25;

the core body (31,32) relative one side is equipped with alternate arrangement's connecting protrusion (A), two core body (31,32) pass through connecting protrusion (A) link to each other, and middle connecting protrusion (A) is located support frame (11) are inboard.

4. The transformer according to claim 1, wherein a row of pin terminals (12a) are arranged at intervals on two sides of the base (12), and the pin terminals (12a) on each side have a pitch of 1.8-1.9 mm;

the pin terminal (12a) is made of phosphor bronze, and a nickel layer with the thickness of 1.2-1.3 um and a tin layer with the thickness of 4.5-5.5 um are plated on the surface of the pin terminal;

the length, the width and the height of the frame body (1) are respectively 11.5mm multiplied by 10.9mm multiplied by 4.7 mm;

the end part of the wire winding (2) is fixedly welded with the pin terminal (12a), and the solder is 63Sn37Pb solder wire.

5. A transformer according to claim 3, characterized by further comprising a clamping spring (5), the clamping spring (5) being clamped outside the core (3).

6. The transformer according to claim 1, characterized by comprising three wire windings (2) wound on said supporting frame (11), respectively, two turns of wire windings (2) located at the innermost and outermost sides being primary, one turn of wire winding (2) located in the middle being secondary;

insulating adhesive tapes are arranged among the wire type windings (2) wound adjacently, between the sheet type winding (4) and the wire type winding (2) and on the sheet type winding (4), and two layers of insulating films with the thickness of 0.02-0.03 mm are arranged between the wire type windings (2) wound adjacently;

the wire winding (2) is an enameled wire consisting of a round copper wire and double-layer polyimide film insulating paint wrapped on the outer side of the round copper wire;

the insulating tape and the insulating film are both made of polyimide;

the frame body (1) is made of phenolic polyester.

7. The transformer of claim 1, wherein the transformer is provided with an insulating varnish, and the insulating varnish is an epoxy ester baking insulating varnish formed by mixing epoxy resin, dry vegetable oil acid, amino resin, xylene and butanol.

8. A method for preparing a transformer according to any one of claims 1-7, comprising the steps of:

a. winding the wire winding (2) on the supporting frame (11);

b. the tail end of the wire winding (2) is subjected to paint removal treatment and then is fixed on a pin terminal (12 a);

c. sleeving the sheet type winding (4) on the outer side of the online winding (2);

d. the two core bodies (31,32) are bonded to form the magnetic core (3), and the clamp spring (5) is clamped outside the magnetic core (3).

9. The method according to claim 8, wherein in the step (a), three wire windings (2) of a primary side and a secondary side are wound in a staggered manner, and one insulating tape layer and two insulating films are arranged for each winding of one wire winding (2);

in the step (b), after the three linear windings (2) are wound, removing paint from the two linear windings (2), reserving a paint coating on the other linear winding (2), dividing the end parts of the three linear windings (2) into two strands respectively, and winding the two strands on the pin terminal (12a) by one turn respectively along different hour directions;

in the step (c), firstly, insulating adhesive tapes are arranged on the wire winding (2) on the outermost side and the sheet winding (4), and then the sheet winding (4) is sleeved on the outer side of the wire winding (2);

in the step (d), the surfaces of the core bodies (31,32) are cleaned and dried by using an absolute ethyl alcohol cotton ball, then the prepared bonding glue is uniformly coated on the bonding surfaces of the core bodies (31,32), and then the core bodies (31,32) are bonded and assembled on the frame body (1) to form the magnetic core (3).

10. The method of claim 8, further comprising:

e. dipping paint on the transformer;