Injection mold

Abstract

The utility model provides an injection mold. The injection mold comprises a lower mold and an upper mold, wherein the upper mold comprises a cover plate and a sealing plate; the cover plate is provided with a first avoiding hole. The sealing plate comprises a base plate, the base plate is arranged on one side of the cover plate, a first protruding column is arranged on the surface, facing the cover plate, of the base plate, the first protruding column is a flexible column, the first protruding column is inserted into the first receding hole and provided with a first through hole, the first through hole is used for the wiring terminal to penetrate through, and the first protruding column is used for filling a gap between the wiring terminal and the first receding hole. By using the injection mold, the structure of the power module is simplified, and the production cost of the power module is reduced.

Description

Technical Field

[0001] The present application relates to the field of preparation of power modules, and in particular to an injection mold for a power module. Background Art

[0002] Power modules can be used in electronic devices to achieve functions such as voltage conversion, current control, reversible transformation, and temperature management. The existing power modules have connection terminals that can extend from the top, and the connection terminals are generally PIN pins. Power modules with PIN pins on the top can be divided into glue-filled and plastic-sealed types. Plastic-sealed modules usually use plastic encapsulation materials to cover the internal structure to protect internal components and provide safety protection capabilities. During plastic encapsulation, the semi-finished product of the power module needs to be placed in the injection mold, and the plastic encapsulation material is filled after the mold is closed. The power module is obtained after the plastic encapsulation material is solidified.

[0003] For power modules with PIN pins protruding from the top, the top of the PIN pin will be higher than the upper surface of the power module. In order to avoid interference between the upper cavity and the PIN pin when the mold is closed, it is necessary to dig an avoidance hole at the top of the upper cavity corresponding to the position of the PIN pin, and the part of the PIN pin higher than the upper surface of the power module enters the avoidance hole when the mold is closed. The final shape of the power module is controlled by the shape of the upper and lower mold cavities. In order to prevent high-temperature mold flow from flowing into the avoidance hole during injection molding, the avoidance hole needs to be sealed, otherwise it will cause glue overflow, making the power module unusable. At present, in the plastic sealing process of power modules with PIN pins protruding from the top, a sealing plate is usually used on the inner surface of the upper cavity to block the avoidance hole to prevent glue overflow. Specifically, the sealing plate is provided with a through hole at the position where the PIN pin is protruding from the through hole, and the PIN pin extends into the avoidance hole of the upper cavity through the through hole, and the sealing plate and the PIN pin are interference fit. After the mold is closed, the sealing plate contacts the inner surface of the upper cavity and blocks the avoidance hole, thereby preventing high-temperature mold flow from entering the avoidance hole. This method requires a separate sealing plate to be manufactured, and after plastic packaging, the sealing plate will remain in the power module due to the wrapping of the sealing material on the sealing plate, thereby increasing the structural complexity and production cost of the power module. Utility Model Content

[0004] The present application provides an injection mold to simplify the structure of a power module and reduce the cost of the power module.

[0005] In a first aspect, the present application provides an injection mold, comprising a lower mold and an upper mold that can be sealed with the lower mold, wherein the upper mold comprises a cover plate and a sealing plate. The cover plate is provided with a first avoidance hole. The sealing plate comprises a substrate, the substrate is provided on one side of the cover plate, and a first boss is provided on the surface of the substrate facing the cover plate, the first boss is a flexible column, the first boss is inserted into the first avoidance hole and the first boss is provided with a first through hole, the first through hole is used to penetrate a terminal, and the first boss is used to fill the gap between the terminal and the first avoidance hole.

[0006] When the injection mold of the present application is used for injection molding, the cover plate can be arranged toward the injection cavity of the injection mold, and the sealing plate is arranged on the side of the cover plate away from the injection cavity. The connection terminal of the power module, such as a PIN needle, can be arranged in the first through hole of the first boss. The first boss is further arranged in the avoidance hole of the cover plate. Since the first boss is a flexible column, it can be deformed in the avoidance hole, so that the first boss can be used to seal the gap between the connection terminal and the avoidance hole. When the injection mold of this structure is used for injection molding, since the sealing plate is arranged on the side away from the injection cavity, it will not directly contact the injection liquid, and will not be covered by the plastic sealing material after injection molding. Therefore, it can be separated from the power module, reducing the structural components of the power module, realizing the reuse of the sealing plate, and reducing the production cost of the power module.

[0007] A second protrusion is provided on the side of the substrate away from the first protrusion, and in the axial direction of the first protrusion, the first protrusion and the second protrusion are arranged one by one, and the first through hole passes through the second protrusion. The second protrusion can play a certain protective role on the connection terminal.

[0008] In an optional implementation, the injection mold further includes a pressing plate, the pressing plate is provided with a second avoidance hole, the second avoidance hole is provided corresponding to the second convex column, the second convex column is inserted into the second avoidance hole, and the second convex column is a flexible column. The second avoidance hole may be a through hole or a blind hole. During injection molding, the pressing plate is used to squeeze the second convex column. Since the second convex column is a flexible column, the PIN needle can be wrapped by the deformation of the second convex column, thereby preventing the injection liquid from entering the hole corresponding to the second convex column and preventing the PIN needle from being wrapped by the injection liquid.

[0009] The second protrusion is a cone structure, and the outer diameter of the second protrusion gradually decreases along the axial extension direction of the second protrusion. The second protrusion is set as a cone structure, which can facilitate the pressing block to squeeze the second protrusion, so that the second protrusion is deformed and better wraps the PIN.

[0010] In an optional implementation, the sealing plate is a flexible sealing plate. For example, the sealing plate can be a silicone plate. The sealing plate is a flexible plate as a whole, which is convenient for processing and manufacturing the sealing plate, and during the extrusion process, the sealing plate is convenient for deformation, so that the first protrusion achieves a better sealing effect.

[0011] In an optional implementation, the cover plate may be a steel plate. Optionally, the pressure plate may also be a steel plate.

[0012] In an optional implementation, the upper mold also includes an upper frame, the upper frame is provided with an opening, the cover plate is arranged at the opening and blocks the opening, the upper frame and the lower mold are covered together to form the injection cavity, and the substrate is arranged on a side of the cover plate away from the injection cavity.

[0013] The injection mold of the present application can realize the separation of the sealing plate and the plastic sealing material. By changing the opening position of the sealing layer, it can be applied to various platform-based power module products. For different power modules, only the corresponding sealing plate needs to be replaced according to the position of the PIN needle. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of a power module according to an embodiment;

[0015] Figure 2 A schematic structural diagram of an injection mold according to an embodiment;

[0016] Figure 3 is a schematic structural diagram of a sealing assembly according to an embodiment;

[0017] Figure 4 is a schematic cross-sectional structure diagram of a sealing assembly according to an embodiment;

[0018] Figure 5 It is a partial enlarged structural schematic diagram of a sealing plate of an embodiment;

[0019] Figure 6 It is a schematic diagram of an enlarged structure of the assembly of a cover plate and a sealing plate in one embodiment;

[0020] Figure 7 It is a partial enlarged structural schematic diagram of a pressing block in one embodiment;

[0021] Figure 8 A schematic diagram of the injection molding process of an embodiment.

[0022] Reference numerals:

[0023] 01-circuit board; 02-pin needle; 03-plastic sealing layer;

[0024] 10-lower mold; 11-upper mold; 12-upper frame; 121-opening;

[0025] 20-sealing assembly; 21-cover plate; 211-first avoidance hole; 22-sealing plate; 221-base plate; 222-first convex column; 223-first through hole;

[0026] 224 - second protruding column; 23 - pressing plate; 231 - second avoidance hole. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0028] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "an", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context.

[0029] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear at different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0030] A power module is an electronic device used to manage and regulate power transmission and conversion. Power modules can be used in different application scenarios such as electronic devices, electric vehicles, solar power generation systems, and industrial robots to achieve different control functions. The main functions of a power module include: 1) Voltage conversion: The power module can convert the voltage of the power supply from one level to another. This is very important for adapting the power supply to different equipment or system requirements. 2) Current control: It can control the magnitude of the current to ensure that the power supply current is within an acceptable range. This is very important to prevent overcurrent from damaging equipment or circuits. 3) Reversible conversion: Some power modules have a reverse conversion function that can convert DC power to AC power or vice versa. This is useful in various applications, such as inverters used to convert DC power generated by solar cells into AC power that can be used for home appliances. 4) Temperature management: Power modules usually include temperature sensors and heat sinks to ensure that they do not overheat during operation.

[0031] Figure 1 Schematic diagram of the structure of a power module. Figure 1 Figure (a) is a schematic diagram of the structure in the unsealed state. Figure 1 Figure (b) is a schematic diagram of the structure after plastic packaging. Figure 1As shown in Figure (a), the semi-finished power module in the un-plasticized state generally includes a circuit board 01 and a connection terminal, as well as components such as bonding wires. Among them, the connection terminal can be a PIN pin 02. The number of PIN pins 02 can be multiple. Figure 1 In the structure shown in Figure (a), the power module has a top-out PIN 02 structure. In this type of PIN 02-out power module, all PIN 02 pins are led out from the top of the power module and connected to the circuit board 01 by crimping or welding, thereby realizing the electrical function of the power module. The lower surface of the power module of this type of structure can be a heat dissipation surface, which can be connected to a radiator to dissipate the heat generated during operation in a timely manner. Figure 1 As shown in FIG. 8( b ), after the semi-finished module is plastic-sealed, the power module obtained after the plastic-sealing may further include a plastic-sealing layer 03 , and the plastic-sealing layer 03 is used to protect the circuit board 01 .

[0032] Among them, when the power module is encapsulated in plastic, an injection mold is required to achieve the encapsulation. Figure 2 FIG. 1 is a schematic diagram of the structure of an injection mold according to an embodiment of the present invention. Figure 2 As shown, the injection mold of the embodiment of the present application includes a lower mold 10 and an upper mold 11, and the lower mold 10 has a receiving cavity. The receiving cavity of the lower mold 10 can be used to place the circuit board of the power module. Figure 2 The upper mold 11 may include an upper frame 12. The upper frame 12 and the lower mold 10 are covered to form an injection cavity in the middle. The connection between the upper frame 12 and the lower mold 10 may be a detachable connection such as a snap connection or a plug connection. Figure 2 Taking the position shown as an example, an opening 121 is provided at the top of the upper frame 12. The opening 121 is connected to the injection cavity. In addition to the upper frame 12, the upper mold 11 also includes a sealing component 20 for blocking the opening 121. The sealing component 20 covers the opening 121 of the upper frame 12 and is sealed and connected to the upper frame 12.

[0033] Figure 3 Figure 1 is a schematic diagram of the structure of a sealing component. Figure 3 As shown, the sealing assembly 20 includes a cover plate 21 and a sealing plate 22. Figure 2 The cover plate 21 covers the opening 121 of the upper frame 12 and blocks the opening 121 of the upper frame 12. The cover plate 21 can be a steel cover plate 21. The connection between the cover plate 21 and the upper frame 12 can be a detachable connection method such as plug-in, clip-on or overlap. During the injection molding process, the circuit board 01 of the power module is placed in the injection molding cavity of the lower mold 10, and the PIN pin 02 as the connection terminal needs to extend from the injection molding cavity. Figure 4 FIG. 1 is a schematic cross-sectional view of a sealing assembly according to an embodiment of the present invention. Figure 4As shown, the cover plate 21 is provided with a first avoidance hole 211 for inserting the PIN needle 02. The number of the first avoidance holes 211 can be multiple. The number of the first avoidance holes 211 can be determined according to the number of the PIN needles 02. The PIN needles 02 and the first avoidance holes 211 can be arranged in a one-to-one correspondence. During the injection molding process, each PIN needle 02 can extend from a first avoidance hole 211.

[0034] Continue to refer to Figure 2 Since the cover plate 21 and the PIN needle 02 are both made of metal, if the two are connected by interference fit, it is easy to cause the PIN needle 02 to bend and damage, affecting subsequent use; if there is a gap between the two, during the injection molding process, the high-temperature injection liquid is easy to seep through the first avoidance hole 211. Therefore, the sealing assembly 20 of the present application includes a sealing plate 22 in addition to the cover plate 21.

[0035] Figure 5 FIG. 2 is a schematic diagram of a partially enlarged structure of a sealing plate 22 according to an embodiment of the present invention. Figure 5 As shown, the sealing plate 22 includes a base plate 221 and a first protruding column 222 . Figure 6 FIG. 1 is a schematic diagram of the connection structure of a substrate and a sealing plate according to an embodiment of the present invention. Figure 5 and Figure 6 , wherein the substrate 221 is arranged on the side of the cover plate 21 away from the injection cavity. The first boss 222 is arranged on the side surface of the substrate 221 facing the injection cavity. The number of the first boss 222 can be multiple, and the multiple first bosses 222 are arranged in a one-to-one correspondence with the multiple first avoidance holes 211. After assembly, each first boss 222 can be inserted into a first avoidance hole 211. Among them, each first boss 222 can be provided with a first through hole 223, and each PIN needle 02 can be self-pierced in the first through hole 223. The first boss 222 is a flexible column, which can prevent the PIN needle 02 from being worn when the PIN needle 02 is penetrated. In addition, the first boss 222 is a flexible column, which can make the first boss 222 fill the gap between the PIN needle 02 and the hole wall of the first avoidance hole 211, thereby reducing the overflow of the injection liquid.

[0036] The liquid inlet of the injection mold of the embodiment of the present application may be disposed on the side of the lower mold 10 or the side of the upper frame 12 , and the injection liquid is introduced into the injection cavity through the liquid inlet.

[0037] After injection molding using the injection mold of the embodiment of the present application, since the sealing plate 22 is disposed above the cover plate 21, rather than disposed in the injection molding cavity, the sealing plate 22 can be separated from the injection molding layer and will not be wrapped by the injection molding layer. After the injection molding is completed, the sealing plate 22 and the cover plate 21 can be disassembled in turn to achieve the recycling of the sealing plate 22 and reduce the production cost of the power module.

[0038] Continue to refer to Figure 5and Figure 6 In the sealing plate 22, a second boss 224 is provided on the other side of the substrate 221, that is, the side away from the first boss 222. The second boss 224 is arranged in a one-to-one correspondence with the first boss 222. Along the axial direction of the first boss 222, the first through hole 223 penetrates the second boss 224, so that the PIN needle 02 can be exposed from the second boss 224. The second boss 224 is a flexible column to protect the PIN needle 02. The sealing plate 22 composed of the second boss 224, the substrate 221 and the first boss 222 can be an integral structure. The sealing plate 22 as a whole can be a flexible sealing plate 22. The sealing plate 22 can be made of silicone.

[0039] Continue to refer to Figure 2 In addition to the cover plate 21 and the sealing plate 22, the upper mold of the embodiment of the present application also includes a pressing plate 23. The pressing plate 23 can be a steel plate. Figure 7 FIG. 1 is a schematic diagram of a partially enlarged structure of a pressing plate of an embodiment. Figure 2 and Figure 7 As shown, the pressing plate 23 is provided with a second avoidance hole 231, which is a through hole or a blind hole. The second avoidance hole 231 is provided corresponding to the second convex column 224. When the pressing plate 23 is used to apply pressure to the sealing plate 22, the second convex column 224 is inserted into the second avoidance hole 231 to prevent the PIN needle 02 from being bent. When the pressing plate 23 is used to apply an extrusion force to the second convex column 224, the second convex column 224 can be deformed to better wrap the PIN needle 02 to prevent the injection liquid from entering the hole corresponding to the second convex column.

[0040] Among them, refer to Figure 5 and Figure 7 The second boss 224 may be a cone structure, and the outer diameter of the second boss 224 gradually decreases along the axial extension direction of the second boss 224. Correspondingly, the shape of the second avoidance hole 231 may also be a cone. The inner diameter of the second avoidance hole 231 may be slightly smaller than the outer diameter of the second boss 224, so that the inner wall of the second avoidance hole 231 can generate a certain lateral squeezing force on the second boss 224, so that the second boss 224 is deformed to wrap the PIN needle 02.

[0041] It is understandable that the shape of the PIN needle 02 in the embodiment of the present application can be a cylinder, a rectangular prism or a square prism, and accordingly, the shape of the first through hole 223 can be a cylinder, a rectangular prism or a square prism, so that the first protrusion 222 can achieve a better covering effect on the PIN needle 02.

[0042] The structure of the injection mold of the embodiment of the present application is explained above. The injection molding packaging process of the power module will be explained below in combination with the structure of the injection mold.

[0043] Figure 8FIG. 1 is a schematic diagram of the injection molding process of a power module according to an embodiment of the present invention. Figure 8 As shown, the process of injection molding using the injection mold of the embodiment of the present application includes the following steps:

[0044] S1. Before plastic encapsulation, the circuit board 01 and PIN needle 02 of the power module are processed according to the standard process of the power module, for example, the process may include patch, reflow, wire bonding, and PIN needle 02 implantation; the semi-finished product with the circuit board, bonding wire and PIN needle is formed, such as Figure 8 As shown in Figure (a).

[0045] S2. After obtaining the semi-finished product, place the semi-finished product in the cavity of the lower seat body 11, such as Figure 8 As shown in Figure (b).

[0046] S3, close the upper frame 12, place the cover plate 21 at the opening 121 of the upper frame 12 to block the opening 121 of the upper frame 12, and place the sealing plate 22 on the upper surface of the cover plate 21, insert the first protrusion 222 of the sealing plate 22 into the first avoidance hole 211, and make the PIN pin 02 pass through the first through hole 223 of the first protrusion 222, as shown in FIG. Figure 8 As shown in Figure (c).

[0047] S4, the pressing block is pressed down to squeeze the sealing layer, causing the sealing layer to deform and tightly wrap the PIN needle 02. Figure 8 As shown in Figure (d).

[0048] S5, inject the plastic sealing liquid into the side wall of the lower seat body 11 for injection molding, and complete the plastic sealing after solidification. Figure 8 As shown in Figure (e).

[0049] S6, mold opening, separating the upper mold of the injection mold in the reverse order, first lift the pressing block, the sealing layer is deformed and restored, and then separate the sealing plate 22 and the cover plate 21, as shown in FIG. Figure 8 As shown in Figures (f) and (g).

[0050] S7, demoulding, obtaining the finished power module, such as Figure 8 As shown in Figure (h).

[0051] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An injection mold, characterized in that: It comprises a lower mold and an upper mold that can be covered with the lower mold to form an injection cavity, and the upper mold comprises a cover plate and a sealing plate; wherein, The cover plate is provided with a first avoidance hole; The sealing plate includes a substrate, which is arranged on one side of the cover plate. A first boss is provided on the surface of the substrate facing the cover plate. The first boss is a flexible boss. The first boss is inserted into the first avoidance hole and the first boss is provided with a first through hole. The first through hole is used to penetrate a terminal. The first boss is used to fill the gap between the terminal and the hole wall of the first avoidance hole.

2. The injection mold according to claim 1, characterized in that: A second protrusion is provided on a side of the substrate away from the first protrusion. In the axial direction of the first protrusion, the first protrusion and the second protrusion are arranged in one-to-one correspondence, and the first through hole passes through the second protrusion.

3. The injection mold according to claim 2, characterized in that: The injection mold further includes a pressing plate, the pressing plate is provided with a second avoidance hole, the second avoidance hole is arranged corresponding to the second convex column, the second convex column is inserted into the second avoidance hole, and the second convex column is a flexible column.

4. The injection mold according to claim 3, characterized in that: The second avoidance hole is a through hole or a blind hole.

5. The injection mold according to any one of claims 2 to 4, characterized in that: The second convex column is a cone structure, and the outer diameter of the second convex column gradually decreases along the axial extension direction of the second convex column.

6. The injection mold according to any one of claims 2 to 4, characterized in that: The sealing plate is a flexible sealing plate.

7. The injection mold according to claim 5, characterized in that: The sealing plate is a silica gel plate.

8. The injection mold according to any one of claims 1 to 4, characterized in that: The cover plate is a steel plate.

9. The injection mold according to claim 3 or 4, characterized in that: The pressing plate is a steel plate.

10. The injection mold according to any one of claims 1 to 4, characterized in that: The upper mold also includes an upper frame, which is provided with an opening. The cover plate is arranged at the opening and blocks the opening. The upper frame and the lower mold are covered to form the injection cavity. The substrate is arranged on a side of the cover plate away from the injection cavity.

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