Inductor structure and preparation method thereof

Abstract

The invention provides an inductor structure and a preparation method thereof.The preparation method of the inductor structure comprises the steps that a leading-out wire of a coil is placed on a welding piece of an end pole piece, and the end pole piece comprises a pin piece and the welding piece which are connected with each other; the welding piece is bent, so that the outgoing line is wrapped by the welding piece; the outgoing line and the welding piece are welded together to form a first-order preformed inductor; the first-order preformed inductor is placed in a mold cavity, the mold cavity is filled with magnetic powder, and the pin piece extends out of the mold cavity; carrying out a die-casting process on the mold cavity to enable the magnetic powder to form a magnetic core entity so as to obtain a second-order preformed inductor; and the mold cavity is removed, and the pin pieces are bent and attached to the surface of the magnetic core entity, so that the inductor structure is obtained. The integrally-formed inductor solves the problems that the coil leading-out end and the end pole piece of an existing integrally-formed inductor are low in welding reliability and large in cold joint risk.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inductance, in particular to an inductance structure and a preparation method thereof. BACKGROUND

[0002] Inductance is a kind of element capable of converting electrical energy into magnetic energy for storage. Common inductors include laminated inductors, NR winding inductors and integrally formed inductors. The integrally formed inductor has excellent saturation performance and low DC resistance characteristics. With the increasing demand of customers for product current, the integrally formed inductor is more and more favored by customers.

[0003] At present, the coil lead-out end and the end pole piece of the common integrally formed inductor are directly welded together, which is easy to cause unreliable welding and false welding problems. SUMMARY

[0004] The embodiments of the present application provide an inductance structure and a preparation method thereof, which solve the problems of low welding reliability and high risk of false welding of the coil lead-out end and the end pole piece of the existing integrally formed inductor.

[0005] The present application is implemented in the following manner. A preparation method of an inductance structure comprises the following steps.

[0006] The lead-out wire of the coil is placed on the welding piece of the end pole piece, the end pole piece comprising a pin piece and a welding piece connected to each other;

[0007] The welding piece is bent so that the lead-out wire is wrapped by the welding piece;

[0008] The lead-out wire and the welding piece are welded together to form a first-stage preformed inductor;

[0009] The first-stage preformed inductor is placed in a mold cavity, and magnetic powder is filled into the mold cavity, and the pin piece extends out of the mold cavity;

[0010] The mold cavity is subjected to a die casting process so that the magnetic powder forms a magnetic core entity to obtain a second-stage preformed inductor;

[0011] The mold cavity is removed;

[0012] The pin piece is bent and attached to the surface of the magnetic core entity to obtain an inductance structure.

[0013] In one of the embodiments, the welding piece comprises a body portion and a bent portion, and a bent lead wire is formed between the body portion and the bent portion. The step of placing the lead-out wire of the coil on the welding piece of the end pole piece comprises the following steps.

[0014] The coating wrapping the outer periphery of the lead-out wire of the coil is removed;

[0015] The lead-out wire is attached to the soldering sheet by the attaching jig, and the lead-out wire covers the bent lead.

[0016] In one embodiment, the bending of the soldering sheet to wrap the lead-out wire with the soldering sheet comprises:

[0017] The bent portion is bent along the bent lead to position the lead-out wire between the bent portion and the body portion.

[0018] In one embodiment, the welding of the lead-out wire with the soldering sheet to form a first preformed inductor comprises:

[0019] The soldering sheet and the lead-out wire are subjected to a pressure welding process to weld the lead-out wire with the soldering sheet to form a first preformed inductor.

[0020] In one embodiment, the soldering sheet has a solder lug at an end away from the coil, and the bent lead is located in the middle of the solder lug; the welding of the lead-out wire with the soldering sheet to form a first preformed inductor comprises:

[0021] The soldering sheet and the lead-out wire are subjected to a pressure welding process to weld the lead-out wire with the soldering sheet;

[0022] The lead-out wire and the solder lug are subjected to a spot welding process to form a first preformed inductor.

[0023] In one embodiment, the lead-out wire protrudes from the solder lug;

[0024] The length of the lead-out wire protruding from the solder lug is half the diameter of the lead-out wire.

[0025] In one embodiment, the solder lug is arc-shaped.

[0026] The welding spot connecting the lead-out wire and the solder lug is spherical.

[0027] In one embodiment, the magnetic powder comprises alloy powder.

[0028] The alloy powder comprises FeSiCr alloy powder with a median particle size of 8-15 um, epoxy resin glue solution, and m-xylidine curing agent; the epoxy resin glue solution comprises epoxy resin and methyl isopropyl ketone, the proportion of the epoxy resin in the epoxy resin glue solution is 40%-70%, the proportion of the methyl isopropyl ketone in the epoxy resin glue solution is 20%-40%, and the ratio of the m-xylidine curing agent to the epoxy resin glue solution is 1:20-40.

[0029] In one of the embodiments, the magnetic powder comprises carbonyl iron powder.

[0030] In one of the embodiments, after the removal of the mold cavity and before the bending of the pin piece to fit the surface of the magnetic core body to obtain the inductor structure, the method further comprises:

[0031] The second-order pre-formed inductor is placed in a high-temperature oven for heating.

[0032] The application also provides an inductor structure prepared by the method of any of the above embodiments, comprising a magnetic core body, a coil and a terminal piece. The coil is arranged in the magnetic core body, and the coil has a lead-out wire. The terminal piece comprises a pin piece and a soldering piece. The soldering piece is arranged in the magnetic core body, and the soldering piece is bent to wrap the lead-out wire. The lead-out wire is welded to the soldering piece, and the pin piece is bent to fit the surface of the magnetic core body.

[0033] The inductor structure and the preparation method thereof provided by the application have the following beneficial effects. Compared with the prior art, the lead-out wire is placed on the soldering piece of the terminal piece when the lead-out wire and the terminal piece are welded. Then, the soldering piece is bent to wrap the lead-out wire, the contact area of the lead-out wire and the soldering piece is increased, and then the lead-out wire and the soldering piece are welded together by the pressure welding process. In this way, the connection between the lead-out wire and the soldering piece is more firm, the reliability is higher, and the risk of virtual welding of the lead-out wire is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flowchart of the preparation method of the inductor structure provided by the application;

[0035] Figure 1-1 is a schematic diagram of the terminal piece;

[0036] Figure 1-2 is Figure 1 is a schematic diagram of the device after the operation of step S101 in the method;

[0037] Figure 1-3 is Figure 1 is a schematic diagram of the device after the operation of step S102 in the method;

[0038] Figure 1-4 is Figure 1 is a schematic diagram of the device after the operation of step S106 in the method;

[0039] Figure 1-5 is Figure 1 is a schematic diagram of the device after the operation of step S107 in the method;

[0040] Figure 1-6 is a schematic diagram of a plurality of terminal pieces on the same material piece;

[0041] Figure 2 is another flowchart of the method for manufacturing the inductance structure provided by the embodiments of the present application;

[0042] Figure 3 is Figure 2 is a flowchart of step S204 in the method of claim 1.

[0043] Figure 3-1 is Figure 3 is a schematic diagram of the device after the operation of step S302 in the method of claim 2.

[0044] In the figure: 1, magnetic core entity; 2, coil; 20, lead-out wire; 3, end pole piece; 31, pin piece; 32, soldering piece; 321, body part; 322, bending part; 323, bending lead wire; 324, solder lug; 4, soldering point. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0046] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0047] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0048] In addition, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0049] It should be noted that the same reference signs are used to represent the same component or the same part in the embodiments of the present application. For the same parts in the embodiments of the present application, only one part or component may be marked with a reference sign in the drawings, and it should be understood that the reference sign is also applicable to other same parts or components.

[0050] The embodiments of the present application provide an inductance structure and a preparation method thereof, which solve the problem of low welding reliability and high risk of virtual welding of the coil lead-out end and the end pole piece of the existing integrally formed inductance.

[0051] Reference Figure 1 The preparation method of the inductance structure provided by the embodiments of the present application includes the following steps:

[0052] S101, the lead-out wire 20 of the coil 2 is placed on the welding piece 32 of the end pole piece 3, and the end pole piece 3 includes the pin piece 31 and the welding piece 32 connected to each other.

[0053] Reference Figure 1-1 , Figure 1-1 is a structural schematic view of the end pole piece 3; Figure 1-1 The welding piece 32 in the structural schematic view of the end pole piece 3 includes the body part 321 and the bending part 322, and the bending lead wire 323 is formed between the body part 321 and the bending part 322.

[0054] Figure 1-2 is a schematic view of the device after the operation of the above step S101.

[0055] It should be noted that the coil 2 in the embodiments of the present application can be a high-temperature self-adhesive coil, which can also be called a high-temperature self-adhesive wire. Since the coil 2 is prepared by winding copper wire multiple times and multiple layers, the high-temperature self-adhesive wire is used when manufacturing the coil 2, so that the wire can be heated while being wound. In this way, the film layer wrapped outside the wire will melt, so that the wires in contact with each other will be adhered together. When the coil 2 is prepared, the heating of the coil 2 is stopped, and the multiple layers or multiple turns of the coil 2 are adhered together, thereby facilitating the prepared coil 2 to be not loose during use and the structure to be more stable.

[0056] The end pole piece 3 in the embodiments of the present application can be made of tin-plated copper material, that is, a layer of tin film is plated on the copper sheet. In this way, the welding effect can be better and the welding efficiency can be improved when the lead-out wire 20 and the end pole piece 3 are welded.

[0057] It can be understood that the coil 2 has two lead-out wires 20, and each lead-out wire 20 is connected to an end pole piece 3.

[0058] 102, the welding piece 32 is bent so that the lead-out wire 20 is wrapped by the welding piece 32.

[0059] Reference Figure 1-3, Figure 1-3 A schematic diagram of the device after step S102.

[0060] S103, the lead-out wire 20 and the soldering sheet 32 are welded together to form a first-stage pre-formed inductor.

[0061] It should be noted that since the lead-out wire 20 is wrapped by the soldering sheet 32, the contact area of the lead-out wire 20 and the soldering sheet 32 is increased, the welding point position can be increased when the lead-out wire 20 and the soldering sheet 32 are welded, so that the welding between the lead-out wire 20 and the soldering sheet 32 is more firm, thereby the connection reliability of the lead-out wire 20 and the end pole sheet 3 is improved, and the risk of virtual welding is reduced.

[0062] S104, the first-stage pre-formed inductor is placed in the mold cavity, and the magnetic powder is filled into the mold cavity, and the pin sheet 31 extends out of the mold cavity.

[0063] It should be noted that the magnetic powder can include alloy powder, the alloy powder includes FeSiCr alloy powder with a median particle size of 8um-15um, epoxy resin glue solution, and m-xylidine curing agent, the epoxy resin glue solution includes epoxy resin and methyl isopropyl ketone, the proportion of the epoxy resin in the epoxy resin glue solution is 40%-70%, the proportion of the methyl isopropyl ketone in the epoxy resin glue solution is 20%-40%, and the proportion of the m-xylidine curing agent to the epoxy resin glue solution is 1:20-40.

[0064] In some embodiments, the magnetic powder can also include carbonyl iron powder.

[0065] The step S104 can fill the magnetic powder into the mold cavity through a servo powder feeder, which can improve the filling efficiency and make the filling effect of the magnetic powder in the mold cavity better.

[0066] S105, the mold cavity is subjected to a die casting process to form a magnetic core entity 1 from the magnetic powder, thereby obtaining a second-stage pre-formed inductor.

[0067] It should be noted that the mold cavity includes a mold base and a pressing cover arranged on the mold base, and the mold base has a receiving cavity. After the magnetic powder is filled into the receiving cavity, the pressing cover is pressed on the mold base, so that the magnetic powder is compacted in the receiving cavity. The die casting process is performed on the mold cavity, that is, the pressing cover and the mold base are subjected to pressure together, so that the magnetic powder is die cast to form the magnetic core entity 1, thereby obtaining the earphone pre-formed inductor. The magnetic core entity 1 wraps the soldering sheet 32 of the coil 2 and the end pole sheet 3, so that the connection between the lead-out wire 20 of the coil 2 and the soldering sheet 32 is more firm and has higher reliability.

[0068] S106, the mold cavity is removed.

[0069] Reference Figure 1-4 , Figure 1-4 The device schematic diagram after the step S106 is shown in FIG. 7.

[0070] S107, the pin sheet 31 is bent and attached to the surface of the magnetic core entity 1 to obtain an inductance structure.

[0071] Reference Figure 1-5 , Figure 1-5 The device schematic diagram after the step S107 is shown in FIG. 8.

[0072] Specifically, the pin sheet 31 can be automatically bent by a pin bending machine, which not only improves the bending efficiency, but also makes the bent pin sheet 31 more attached to the surface of the magnetic core entity 1.

[0073] In the embodiment of the present application, when the inductance structure is prepared, the lead-out wire 20 of the coil 2 is first welded together with the end pole sheet 3, then the magnetic core entity 1 which wraps the coil 2 and the welding sheet 32 of the end pole sheet 3 is formed, and finally the pin sheet 31 of the end pole sheet 3 is attached to the surface of the magnetic core entity 1 to obtain the inductance structure. This preparation method can integrally form the inductance, so that the performance of the inductance is better. When the lead-out wire 20 and the end pole sheet 3 are welded, the lead-out wire 20 is placed on the welding sheet 32 of the end pole sheet 3, the welding sheet 32 is then bent to wrap the lead-out wire 20, and then the lead-out wire 20 and the welding sheet 32 are welded together by pressure welding process. In this way, the connection between the lead-out wire 20 and the welding sheet 32 is more firm, the reliability is higher, and the risk of virtual welding of the lead-out wire 20 is reduced.

[0074] The above steps S101-S107 of the embodiment of the present application are used to prepare the inductance structure, which is used as an example to explain the preparation method of the inductance structure. In actual preparation of the inductance structure, multiple inductance structures can be prepared at one time.

[0075] Specifically, the first step is to refer to Figure 1-6 When the end pole sheet 3 is prepared, multiple end pole sheets 3 are made on the same material sheet. Then, the multiple coils 2 are respectively welded together with the multiple end pole sheets 3 by using the above preparation steps to obtain multiple first-order pre-formed inductances. Then, the multiple first-order pre-formed inductances are placed in multiple mold cavities respectively, and magnetic powder is filled into each mold cavity. Finally, the multiple mold cavities are subjected to pressure casting process together, and then the multiple mold cavities are removed to obtain multiple second-order pre-formed inductances. At this time, the multiple second-order pre-formed inductances are connected together through the part of the material sheet except the multiple end pole sheets 3. Therefore, the automatic bending machine is used to cut off the excess part of the material sheet except the end pole sheet 3, so that multiple independent second-order pre-formed inductances are obtained. Then, the pin sheet 31 of each second-order pre-formed inductance is bent and attached to the surface of the magnetic core entity 1 to form a surface electrode, and multiple inductance structures are obtained.

[0076] It should be noted that the above method for preparing the inductance structure is also applicable to the preparation of a winding patch power inductor similar to the end welding.

[0077] In the embodiment of the present application, the welding sheet 32 includes a body part 321 and a bending part 322, and a bending lead 323 is formed between the body part 321 and the bending part 322. On this basis, referring to Figure 2 The method for preparing the inductance structure provided in the embodiment of the present application includes the following steps:

[0078] S201, remove the coating wrapped around the outer periphery of the lead-out wire 20 of the coil 2.

[0079] S202, adhere the lead-out wire 20 to the welding sheet 32 by using an adhering jig, and the lead-out wire 20 covers the bending lead 323.

[0080] The schematic diagram after the above step S202 operation can be referred to Figure 1-2 .

[0081] It should be noted that the lead-out wire 20 can be precisely covered by the bending lead 323 by using the adhering jig to adhere the lead-out wire 20 to the welding sheet 32, so that the alignment of the lead-out wire 20 and the welding sheet 32 is more accurate, and manual operation is avoided, thereby improving the efficiency of adhering the lead-out wire 20 to the welding sheet 32.

[0082] S203, bend the bending part 322 along the bending lead 323, so that the lead-out wire 20 is located between the bending part 322 and the body part 321.

[0083] The schematic diagram after the above step S203 operation can be referred to Figure 1-3 .

[0084] It should be noted that after the step S203 operation, the lead-out wire 20 can be in contact with the bending part 322, the body part 321, and the bending lead 323. Compared with the prior art in which the lead-out wire 20 is directly in contact with the end pole sheet 3 for welding, the contact area of the lead-out wire 20 and the end pole sheet 3 is small, the welding point is less, and false welding is easy to occur, and the reliability is low. The embodiment of the present application can increase the contact area of the lead-out wire 20 and the welding sheet 32 by the step S203, and the subsequent welding points can also be increased accordingly, thereby effectively reducing the risk of false welding of the lead-out wire 20 and improving the reliability of the connection between the lead-out wire 20 and the end pole sheet 3.

[0085] It can be understood that as long as the lead-out wire 20 is attached to the body part 321 and the bent part 322 of the welding sheet 32, the contact area between the lead-out wire 20 and the welding sheet 32 can be increased, so that the welding firmness of the lead-out wire 20 and the welding sheet 32 is stronger. The contact position of the lead-out wire 20 and the welding sheet 32 is not specifically limited, and the position of the bent lead 323 on the welding sheet 32 is also not specifically limited. Therefore, the bent lead 323 can be located at the middle position of the welding sheet 32, that is, the area of the body part 321 and the bent part 322 is equal. After the bent part 322 is bent along the bent lead 323, it will overlap with the body part 321. Thus, the surfaces of the body part 321 and the bent part 322 in contact can be welded together during the pressure welding process, so that the welding firmness of the body part 321, the bent part 322 and the lead-out wire 20 is stronger.

[0086] In the actual operation of the above step S203, before the bent part 322 is folded, the lead-out wire 20 and the body part 321 need to be fixed by a jig to prevent the bent part 322 from shifting the body part 321 when bending, affecting the attachment effect of the lead-out wire 20 and the welding sheet 32, and also enabling the bent part 322 to better achieve bending.

[0087] S204, the lead-out wire 20 and the welding sheet 32 are welded together to form a first preformed inductor.

[0088] It should be noted that since the lead-out wire 20 is wrapped by the welding sheet 32, that is, the contact area between the lead-out wire 20 and the welding sheet 32 is increased, welding the lead-out wire 20 and the welding sheet 32 together can increase the number of welding points between the lead-out wire 20 and the welding sheet 32, thereby enhancing the firmness of the lead-out wire 20 and the welding sheet 32, and enhancing the reliability of the connection between the lead-out wire 20 and the end pole sheet 3, greatly reducing the risk of false welding.

[0089] The above first preformed inductor refers to the device structure after the lead-out wire 20 and the welding sheet 32 are welded together, that is, the device structure at one stage in the process of manufacturing the inductor structure, which can be referred to as Figure 1-3 The first preformed inductor needs to meet the requirement that the lead-out wire 20 does not shake, to ensure that the lead-out wire 20 and the welding sheet 32 are firmly welded without false welding.

[0090] S205, the first preformed inductor is placed in the mold cavity, and the mold cavity is filled with magnetic powder, and the pin sheet 31 extends out of the mold cavity.

[0091] It should be noted that the magnetic powder can include an alloy powder, the alloy powder includes FeSiCr alloy powder with a median particle size of 8um-15um, an epoxy resin glue solution, and a m-xylidine curing agent, the epoxy resin glue solution includes epoxy resin and methyl isopropyl ketone, the proportion of the epoxy resin in the epoxy resin glue solution is 40%-70%, the proportion of the methyl isopropyl ketone in the epoxy resin glue solution is 20%-40%, and the ratio of the m-xylidine curing agent to the epoxy resin glue solution is 1:20-40.

[0092] In some embodiments, the magnetic powder can also include carbonyl iron powder.

[0093] S206, a die cavity is subjected to a die casting process to form a magnetic core body 1 from the magnetic powder, to obtain a second-order pre-formed inductor.

[0094] S207, the die cavity is removed.

[0095] The device schematic diagram after the above step S207 operation can refer to Figure 1-4 .

[0096] S208, the second-order pre-formed inductor is placed in a high-temperature oven for heating.

[0097] It should be noted that the operation of the above step S208 can heat the second-order pre-formed inductor, which can heat the magnetic core body 1, thereby improving the strength of the magnetic core body 1.

[0098] The above high-temperature oven can be a box oven or a tunnel furnace.

[0099] S209, the pin sheet 31 is bent and attached to the surface of the magnetic core body 1 to obtain an inductor structure.

[0100] The device schematic diagram after the above step S209 operation can refer to Figure 1-5 .

[0101] In the embodiments of the present application, the specific operation mode of the above step S204 can be various.

[0102] The specific operation mode one of the above step S204 includes the following steps:

[0103] The welding sheet 32 and the lead wire 20 are subjected to a pressure welding process to weld the lead wire 20 and the welding sheet 32 together to form a first-order pre-formed inductor.

[0104] It should be noted that the lead-out wire 20 is first attached to the welding sheet 32 through step S202, and then the welding sheet 32 is bent so that the lead-out wire 20 is located between the bent portion 322 and the body portion 321 of the welding sheet 32. In this way, the lead-out wire 20 can be closely attached to the welding sheet 32, and then the welding sheet 32 and the lead-out wire 20 are welded together through the pressure welding process. This can make the welding of the lead-out wire 20 on the welding sheet 32 more secure, and greatly reduce the risk of virtual welding.

[0105] Further, with reference to Figure 1-1 , the end of the welding sheet 32 away from the coil 2 has a welding lug 324, and the bent lead wire 323 is located in the middle of the welding lug 324.

[0106] On this basis, with reference to Figure 3 , the second specific operation mode of step S204 includes the following steps:

[0107] S301, the welding sheet 32 and the lead-out wire 20 are subjected to a pressure welding process so that the lead-out wire 20 is welded together with the welding sheet 32.

[0108] The schematic diagram after step S301 operation can be referred to as Figure 1-3 .

[0109] S302, the lead-out wire 20 and the welding lug 324 are subjected to a spot welding process to form a first pre-formed inductor.

[0110] With reference to Figure 3-1 , Figure 3-1 , the device schematic diagram after step S302 operation.

[0111] Among them, the spot welding process adopts laser energy welding, and laser spot welding is performed at the contact position of the end of the lead-out wire 20 and the welding lug 324, so that the end of the lead-out wire 20 and the welding lug 324 are fused together, and the welding is more secure.

[0112] It should be noted that when welding between the lead-out wire 20 and the welding tab 32 is realized through the above steps S301-S302, the lead-out wire 20 is first attached to the welding tab 32 by using a jig, and then the welding tab 32 is bent to make the lead-out wire 20 closely attached to the welding tab 32, to complete a physical compression connection. Then, the welding tab 32 and the lead-out wire 20 are welded together through a pressure welding process, to complete a second welding. This can make the welding of the lead-out wire 20 on the welding tab 32 more firm, and greatly reduce the risk of false welding. Further, the lead-out wire 20 and the lug 324 are subjected to a spot welding process, to weld the end of the lead-out wire 20 with the welding tab 32, to complete a third welding, so that the welding firmness of the lead-out wire 20 on the welding tab 32 is further improved. The lead-out wire 20 and the welding tab 32 are subjected to a physical compression connection, a second welding and a third welding in turn, which can greatly improve the welding firmness of the lead-out wire 20 on the welding tab 32 and reduce the risk of false welding.

[0113] Further, referring to Figure 1-1 and Figure 1-2 , the lead-out wire 20 can be arranged to protrude from the lug 324, and the lug 324 is in a circular arc shape. In this way, it is more convenient to weld the end of the lead-out wire 20 with the lug 324, and the welding between the lead-out wire 20 and the welding tab 32 can be ensured to be more firm.

[0114] The length of the lead-out wire 20 protruding from the lug 324 can be set to be half of the diameter of the lead-out wire 20. In this way, the length of the lead-out wire 20 protruding from the lug 324 will not be too long, and the welding angle will not need to be constantly changed during laser welding, which increases the welding difficulty. At the same time, the length of the lead-out wire 20 protruding from the lug 324 will not be too short, and the part of the lead-out wire 20 protruding from the lug 324 can be melted during laser spot welding, to be firmly welded with the lug 324, which is conducive to further improving the welding firmness between the lead-out wire 20 and the lug 324.

[0115] When the lug 324 is in a circular arc shape, the end of the lead-out wire 20 and the lug 324 will form a spherical weld point 4 after laser spot welding, as shown in Figure 3-1 . It can also be said that the lug 324 is arranged in a circular arc shape in order to form a spherical weld point 4. Compared with other shapes of the lug 324, the weld point formed after laser spot welding will have edges and corners, which may cause a scratch line during subsequent movement. The lug 324 arranged in a circular arc shape can form a spherical weld point 4, and the surface of the weld point 4 is relatively smooth, which can avoid the scratch line during movement.

[0116] After the inductance structure is prepared by the preparation method of the embodiment of the application, the inductance structure can be tested for voltage resistance by using a Chrom19301A pulse voltage resistance tester, and then high-frequency L / Q value sorting and DCR sorting are performed. The inductance structure that passes the sorting is subjected to 265 DEG C high-temperature reflow soldering, and then sorted for electrical properties again, so as to more thoroughly exclude open-circuit / virtual-welding inductance structures.

[0117] The embodiment of the application further provides an inductance structure prepared by using the preparation method of the above-described embodiment, which can be prepared by referring to Figure 1-5 The inductance structure comprises a magnetic core entity 1, a coil 2 and a terminal sheet 3. The coil 2 is arranged in the magnetic core entity 1, and the coil 2 has a lead-out wire 20. The terminal sheet 3 comprises a pin sheet 31 and a soldering sheet 32. The soldering sheet 32 is arranged in the magnetic core entity 1, and the soldering sheet 32 is bent to wrap the lead-out wire 20. The lead-out wire 20 is welded to the soldering sheet 32, and the pin sheet 31 is bent to adhere to the surface of the magnetic core entity 1.

[0118] In the inductance structure of the embodiment of the application, the soldering sheet 32 of the terminal sheet 3 is bent to wrap the lead-out wire 20 of the coil 2, which can greatly increase the contact area of the lead-out wire 20 and the soldering sheet 32, so that the firmness of the lead-out wire 20 and the soldering sheet 32 after welding is improved, and the risk of virtual welding is greatly reduced.

[0119] The above merely describes the specific embodiments of the application, but the protection scope of the application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for preparing an inductor structure, characterized in that: include: Placing the lead wire (20) of the coil (2) on the welding piece (32) of the end piece (3), wherein the end piece (3) comprises a pin piece (31) and a welding piece (32) connected to each other; Bending the welding sheet (32) so that the lead wire (20) is wrapped by the welding sheet (32); Welding the lead wire (20) and the welding sheet (32) together to form a first-order preformed inductor; Placing the first-order preformed inductor in a mold cavity, and filling the mold cavity with magnetic powder, with the pin piece (31) extending out of the mold cavity; Performing a die-casting process on the mold cavity to form the magnetic powder into a magnetic core entity (1) to obtain a second-order preformed inductor; removing the mold cavity; The pin piece (31) is bent and attached to the surface of the magnetic core entity (1) to obtain an inductor structure.

2. The preparation method according to claim 1, characterized in that The welding piece (32) comprises a main body (321) and a bent portion (322), a bent lead (323) is formed between the main body (321) and the bent portion (322), and the lead wire (20) of the coil (2) is placed on the welding piece (32) of the end plate (3), comprising: removing the film wrapped around the outer periphery of the lead wire (20) of the coil (2); The lead wire (20) is attached to the welding sheet (32) by a bonding jig, and the lead wire (20) covers the bent lead wire (323).

3. The preparation method according to claim 2, characterized in that The step of bending the welding sheet (32) so that the lead wire (20) is wrapped by the welding sheet (32) comprises: The bent portion (322) is bent along the bent lead (323) so that the lead (20) is located between the bent portion (322) and the main body (321).

4. The preparation method according to claim 2 or 3, characterized in that The step of welding the lead wire (20) and the welding sheet (32) together to form a first-order preformed inductor comprises: A pressure welding process is performed on the welding piece (32) and the lead wire (20), so that the lead wire (20) and the welding piece (32) are welded together to form a first-order preformed inductor.

5. The preparation method according to claim 2 or 3, characterized in that The end of the welding piece (32) away from the coil (2) has a welding ear (324), and the bent lead (323) is located in the middle of the welding ear (324); the lead wire (20) and the welding piece (32) are welded together to form a first-order preformed inductor, comprising: Performing a pressure welding process on the welding piece (32) and the lead wire (20) so that the lead wire (20) and the welding piece (32) are welded together; The lead wire (20) and the welding lug (324) are spot-welded to form a first-order preformed inductor.

6. The preparation method according to claim 5, characterized in that The lead wire (20) protrudes from the soldering lug (324); The length of the lead wire (20) protruding from the soldering ear (324) is half the wire diameter of the lead wire (20).

7. The preparation method according to claim 5, characterized in that The welding ear (324) is in an arc shape; The soldering point (4) connecting the lead wire (20) and the soldering ear (324) is spherical.

8. The preparation method according to any one of claims 1-3, 6-7, characterized in that The magnetic powder includes alloy powder; The alloy powder includes FeSiCr alloy powder with a median particle size of 8um to 15um, epoxy resin glue and m-xylidine curing agent, the epoxy resin glue includes epoxy resin and methyl isopropyl ketone, the epoxy resin accounts for 40% to 70% of the epoxy resin glue, the methyl isopropyl ketone accounts for 20% to 40% of the epoxy resin glue, and the ratio of the m-xylidine curing agent to the epoxy resin glue is 1:20 to 40; Alternatively, the magnetic powder includes carbonyl iron powder.

9. The preparation method according to any one of claims 1-3, 6-7, characterized in that After removing the mold cavity and before bending the pin piece (31) and attaching it to the surface of the magnetic core entity (1) to obtain the inductor structure, the method further includes: The second-order preformed inductor is placed in a high-temperature oven for heating.

10. An inductor structure, characterized in that: The method according to any one of claims 1 to 9 is used for preparation, comprising: Magnetic core entity (1); A coil (2) is disposed in the magnetic core entity (1), and the coil (2) has a lead wire (20); The end pole piece (3) comprises a pin piece (31) and a welding piece (32), wherein the welding piece (32) is arranged in the magnetic core entity (1), the welding piece (32) is bent to wrap the lead wire (20), the lead wire (20) is welded to the welding piece (32), and the pin piece (31) is bent and adhered to the surface of the magnetic core entity (1).

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