Variable cross-section high-frequency induction heating coil and manufacturing method thereof

Abstract

The invention discloses a variable cross-section high-frequency induction heating coil, which comprises a heating coil main body, and a positive connection section and a negative connection section which are connected with the positive electrode and the negative electrode of a power supply at the two ends of the heating coil main body, and the heating coil main body comprises a variable-diameter coil used for the variable cross-section micro position of a workpiece. The heating coil main body is arranged to be the variable-diameter coil at the variable cross-section position of the workpiece, so that the distance between the heating coil main body and the preheating area of the workpiece is basically consistent, and the phenomenon of non-uniform heating caused by inconsistent distance between the cylindrical heating coil and the preheating area in the prior art is avoided; therefore, the heating coil main body can uniformly heat the heating area of the workpiece, and the product quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coil heating, and in particular to a variable-cross-section high-frequency induction heating coil and a manufacturing method thereof. Background Art

[0002] In the prior art, in order to ensure the performance of the assembled thermocouples for aviation, glass sintering is usually used to seal the box and fix it during the processing. High-frequency induction heating is widely used in the sintering process of assembled thermocouples due to its advantages such as fast heating speed, high efficiency and controllable heating area. The shape and size of the high-frequency induction coil directly determine the efficiency and uniformity of heating. For cylindrical or nearly cylindrical regular parts, a circular or cylindrical heating coil is usually used. However, this heating coil has a better heating effect on cylindrical or nearly cylindrical regular parts. For non-cylindrical workpieces, especially workpieces with variable cross-sections or variable diameters, if a circular or cylindrical heating coil is used, the workpiece will be heated too quickly locally, the temperature will be too high, and the workpiece will be heated unevenly or even overheated and ablated. Therefore, it is very important to design an induction heating coil for workpieces with variable cross-sections or diameters so that the workpieces are heated evenly. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a variable cross-section high-frequency induction heating coil, which includes a heating coil body and a positive connection section and a negative connection section connected to the positive and negative electrodes of the power supply at both ends of the heating coil body, and the heating coil body includes a variable diameter coil for the variable cross-section position of the workpiece preheating area. By setting the heating coil body as a variable diameter coil at the variable cross-section position of the workpiece preheating area, the distance between the heating coil body and the workpiece preheating area is basically consistent, avoiding the uneven heating phenomenon caused by the inconsistent distance from the preheating area of ​​the cylindrical heating coil in the prior art, so that the heating coil body of the present invention heats the heating area of ​​the workpiece evenly, improving the product quality.

[0004] Furthermore, the heating coil body also includes an upper annular coil and a lower annular coil connected to both ends of the variable diameter coil.

[0005] In one embodiment, the inner diameter of the coil of the heating coil body is equal to 1.5-2 times the diameter of the preheating area of ​​the workpiece.

[0006] In one embodiment, the height of the heating coil body is equal to the sum of the height of the workpiece preheating area and 4-6 times the coil turn spacing. Through this arrangement, the preheating area is fully surrounded by the heating coil body, avoiding the occurrence of uneven heating at the end of the workpiece preheating area and improving the heating effect.

[0007] In one embodiment, the turn spacing of the heating coil body is equal to 0.8-1.0 times the outer diameter of the metal tube used for the coil. By setting the above turn spacing, the heating effect is uniform, and excessive heating concentration is avoided, which causes the workpiece to be burned by the rapidly increased temperature or reduces the quality of the workpiece.

[0008] In one embodiment, the positive connection section and the negative connection section are provided with a fixing structure for fixing the heating coil. By providing the above fixing structure, the main body of the heating coil can be basically fixed in a certain position, that is, the positioning effect is achieved. As long as the workpiece is positioned in conjunction with other structures, the workpieces can be replaced, thereby improving production efficiency.

[0009] The present invention also provides a method for manufacturing the above-mentioned variable-cross-section high-frequency induction heating coil, comprising the following steps:

[0010] S1: Select a metal tube for the coil and anneal it as a whole;

[0011] S2: Design a winding mold for the heating coil body, and use a metal tube to wind the coil annealed in S1 according to the winding mold to form a heating coil.

[0012] Specifically, in S2, the diameter of the winding mold is 1.5-2 times the diameter of the workpiece heating area; the height of the winding mold is the sum of the height of the workpiece preheating area and 2-3 times the coil turn spacing at both ends, and the parts higher than the workpiece preheating area are located at both ends.

[0013] Furthermore, when the heating coil body is wound, the coil turn spacing is equal to 0.8-1.0 times the outer diameter of the coil metal tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the following briefly introduces the drawings required for use in the specific implementation modes. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 It is a structural schematic diagram of a variable cross-section high-frequency induction heating coil of the present invention;

[0016] Figure 2 It is a structural schematic diagram of a variable cross-section high-frequency induction heating coil (including a fixed structure) of the present invention;

[0017] Figure 3 It is a structural schematic diagram of a workpiece preheating area in a method for preparing a variable-cross-section high-frequency induction heating coil of the present invention;

[0018] Figure 4 It is a structural schematic diagram of a winding mold of the present invention.

[0019] The reference numerals in the figure are as follows: 1 - heating coil body; 2 - positive connecting section; 3 - negative connecting section; 4 - reducing coil; 5 - upper annular coil; 6 - lower annular coil; 7 - ceramic ring. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the content of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The embodiments in the present invention and other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Example 1

[0025] like Figure 1As shown, this embodiment discloses a variable cross-section high-frequency induction heating coil, which includes a heating coil body 1 and a positive connection section 2 and a negative connection section 3 connected to the positive and negative electrodes of the power supply at both ends of the heating coil body 1. The heating coil body 1 is a heating coil used for the preheating area of ​​the workpiece. It simulates the structure of the preheating area of ​​the workpiece and is inserted into the preheating area of ​​the workpiece for heating after combining a certain proportion, or the preheating area of ​​the workpiece is inserted into the heating coil for heating. The latter is generally selected. Specifically, in this embodiment, the heating coil body 1 includes a variable diameter coil 4 for the variable cross-section position of the preheating area of ​​the workpiece, that is, different from the prior art, by changing the existing heating coil of the same diameter, according to the different diameters of the preheating area, a variable diameter coil 4 of corresponding diameter is set at the variable cross-section position. In this implementation, the variable diameter coil 4 is a spiral coil with a gradually increasing diameter. Further, the heating coil body 4 also includes an upper annular coil 5 and a lower annular coil 6 connected to both ends of the variable diameter coil, that is, the two ends of the variable diameter coil form coils of two diameters, which are specifically related to the diameter of the workpiece. Specifically, the inner diameter of the coil of the heating coil body is equal to 1.5-2 times the diameter of the preheating area of ​​the workpiece; further, the upper annular coil 5 and the lower annular coil 6 extend beyond the end portion by at least 2-3 turns of coil turn spacing along the axial direction of the preheating area of ​​the workpiece, that is, the height of the heating coil body 1 is at least equal to the sum of the height of the area to be heated of the workpiece and 4-6 times the coil turn spacing. Further, the turn spacing of the heating coil body 1 is equal to 0.8-1.0 times the outer diameter of the metal tube for the coil. Among them, the positive connecting section 2 and the negative connecting section 3 are not heated for the preheating area of ​​the workpiece, that is, the part outside the two ends of the heating coil body 1, which can be used to connect the positive and negative poles of the power supply and fix the heating coil, and can be a metal tube for the coil, or other metal strips welded to the heating coil body 1. The specific shape is not limited and can be adjusted according to the actual tooling.

[0026] Example 2

[0027] like Figure 2 As shown, this embodiment discloses a variable cross-section high-frequency induction heating coil, which is a variation on the basis of Embodiment 1. Specifically, the positive connecting section 2 and the negative connecting section 3 are provided with a fixing structure for fixing the heating coil. The shape and setting position of the fixing structure are not specifically shown. As long as it can assist in fixing the interface on the tooling frame, specifically, the fixing structure is a ceramic ring 7 fixed on the tooling frame (not shown in the figure), and the positive connecting section 2 and the negative connecting section 3 just pass through. The positive connecting section 2 and the negative connecting section 3 can be fixed by slightly bending them. Of course, the fixing structure can also be other structures and methods that can insulate and fix the heating coil. As for the fixing methods of the ceramic ring 7 on the tooling frame, there are many, such as fixing by a clamp, which will not be repeated here.

[0028] Example 3

[0029] This embodiment discloses a method for preparing a variable cross-section high-frequency induction heating coil, which includes the following steps: S1: Select a metal tube for the coil and anneal it as a whole; S2: Design a winding mold for the main body of the heating coil, and wind the metal tube for the coil annealed in S1 according to the winding mold to form a heating coil. Specifically, in this embodiment, a copper tube with a diameter of 5 mm and a certain length is selected, and the total length is flattened. The copper tube is annealed as a whole using an acetylene flame, and the heating time is 30±5 minutes. In this embodiment, the heating time is 25 minutes; the preheated partial area of ​​the workpiece is measured. In this embodiment, the preheated partial area of ​​the workpiece is measured. Figure 3 The workpiece shown, L1, L2, L3, Φ1, Φ2 and the angle between the variable diameter area and the cylindrical area are measured, wherein L1 is the variable diameter length, L2 is the length of one side of the variable diameter area, and L3 is the preheating area; the parameters of the winding mold are calculated, wherein the length of the variable diameter part remains unchanged, and the shortest length of the winding mold is calculated by addition and subtraction to be L3 (L2+L1+the length of the other side of the variable diameter area) plus 4-6 times the coil turn spacing, wherein 2 times the turn spacing is selected at both ends, and the turn spacing is the same as the diameter of the copper tube as an example, that is, the shortest length of the winding mold is L3+20mm, wherein the diameter of the mold corresponding to the L3 part and the diameter of the extended part are equal to 1.5-2 times the diameter of the L3 part of the workpiece, preferably 2 times, i.e. 2Φ1, the angle of the variable diameter part is consistent with the angle of the workpiece variable diameter part, the length is equal to L1, and the diameter of the remaining part of the mold corresponding to the remaining part is equal to 1.5-2 times the diameter of the remaining part of the workpiece, preferably 2 times, i.e. 2Φ2. For the diameter of the variable diameter part, it can be designed according to the angle between the variable diameter area and the cylindrical area. According to the above data, the mold is processed, such as Figure 4 The winding start point and end point are set according to the length of the corresponding part, and the heating coil is wound according to the coil turn spacing, and at the same time, the positive connection section and the negative connection section are reserved.

[0030] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A variable cross-section high-frequency induction heating coil, characterized in that: It includes a heating coil body and a positive connection section and a negative connection section connected to the positive and negative poles of a power supply at both ends of the heating coil body. The heating coil body includes a variable diameter coil for a variable cross-section position in a preheating area of ​​a workpiece.

2. The variable cross-section high frequency induction heating coil according to claim 1, characterized in that: The heating coil body further includes an upper annular coil and a lower annular coil connected to both ends of the variable diameter coil.

3. The variable cross-section high-frequency induction heating coil according to claim 1, characterized in that: The inner diameter of the coil of the heating coil body is equal to 1.5-2 times the diameter of the preheating area of ​​the workpiece.

4. The variable cross-section high-frequency induction heating coil according to claim 1, characterized in that: The height of the heating coil body is equal to the sum of the height of the workpiece preheating area and 4-6 times the coil turn spacing.

5. The variable cross-section high frequency induction heating coil according to claim 1, characterized in that: The turn spacing of the heating coil body is equal to 0.8-1.0 times the outer diameter of the metal tube used for the coil.

6. The variable cross-section high frequency induction heating coil according to claim 1, characterized in that: The positive connecting section and the negative connecting section are provided with a fixing structure for fixing the heating coil.

7. A method for manufacturing a variable cross-section high-frequency induction heating coil according to claims 1-6, characterized in that: The steps include: S1: Select a metal tube for the coil and anneal it as a whole; S2: Design a winding mold for the heating coil body, and use a metal tube to wind the coil annealed in S1 according to the winding mold to form a heating coil.

8. The method for manufacturing a variable cross-section high-frequency induction heating coil according to claim 7, characterized in that: The diameter of the winding mold is 1.5-2 times the diameter of the workpiece heating area; the height of the winding mold is at least the sum of the height of the workpiece preheating area and the two ends plus 2-3 times the coil turn spacing, and the parts higher than the workpiece preheating area are located at both ends.

9. The method for manufacturing a variable cross-section high-frequency induction heating coil according to claim 7, characterized in that: When the heating coil body is wound, the coil turn spacing is equal to 0.8-1.0 times the outer diameter of the coil metal tube.

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