Thin film capacitor

Abstract

The utility model discloses a film capacitor, which is characterized in that a middle outlet hole is arranged at the circle center of a top cover, and a lead terminal is hermetically connected in the middle outlet hole, so that a first lead passes through a central through hole of a core rod and is electrically connected with a metal spraying layer at the bottom end of a film roll, and a second lead is directly electrically connected with a metal spraying layer at the top end of the film roll, thereby reducing the wiring length and improving the wiring efficiency. The core is positioned and fixed by arranging the positioning mechanism which is in interference fit with the central through hole of the core rod at the bottom of the shell, deviation of the mounting position of the core is avoided, it is guaranteed that the core is centrally mounted at the central position of the shell, and the mounting efficiency and the mounting effect are remarkably improved; the first lead penetrating through the central through hole of the core rod can be accommodated in the lead groove in a matched mode, and it is effectively avoided that a gap is formed between the positioning mechanism and the core rod, and the positioning precision is affected.

Description

Technical Field

[0001] The utility model belongs to the technical field of electrical instruments and relates to a capacitor, in particular to a middle-hole type film capacitor. Background Art

[0002] Capacitors are one of the electronic components used in large quantities in electronic devices. They are widely used in circuits for DC isolation, AC passing, coupling, bypassing, filtering, tuning circuits, energy conversion, and control. Capacitors come in many types depending on the dielectric, such as electrolyte capacitors, paper capacitors, film capacitors, ceramic capacitors, mica capacitors, and air capacitors. Among them, film capacitors use metal foil as electrodes, overlap it with plastic films such as polyethylene, polypropylene, polystyrene, or polycarbonate, and wind it into a cylindrical structure to form a capacitor. With the development of technology, the replacement cycle of electronics, home appliances, communications, and other industries is getting shorter and shorter, and film capacitors have become an indispensable electronic component for promoting the replacement of the above industries with their good electrical performance and high reliability.

[0003] Existing film capacitors usually use metallized film, which is made by vacuum evaporating a thin layer of metal on a plastic film as an electrode, and then winding the metallized film on a core rod to make a core. In the process of making film capacitors, in order to fix the core and ensure complete insulation between the core and the shell, epoxy resin encapsulation is generally used. The epoxy resin used for encapsulation not only has excellent insulation properties, but also adds fillers such as alumina to make it have excellent thermal conductivity. During the epoxy resin encapsulation process, since there is no positioning device on the capacitor shell, the staff needs to manually measure the installation position of the core, and the capacitor core is easy to float when filling the epoxy resin, resulting in deviations in the installation position of the core, and it is impossible to ensure that the core is installed in the center of the shell, resulting in low installation efficiency and poor effect. Utility Model Content

[0004] In order to solve the technical problems existing in the background technology, the utility model proposes a film capacitor, which positions the core by setting a positioning mechanism that can adapt to accommodate the bottom lead of the core, and fixes the core on the basis of optimal wiring, which significantly improves the installation efficiency and installation effect.

[0005] The purpose of the utility model can be achieved through the following technical solutions:

[0006] A film capacitor comprises a shell, a core installed in the shell, a top cover sealed on the shell and a lead terminal passing through the top cover, wherein the core is composed of a hollow core rod and a film roll wound on the core rod, both ends of the film roll are provided with a gold spray layer, the lead terminal has a first lead and a second lead, the lead terminal is sealed and connected to a center hole at the center of the top cover, the first lead passes through the central through hole of the core rod and is electrically connected to the gold spray layer at the bottom end of the film roll, the second lead is electrically connected to the gold spray layer at the top end of the film roll, a positioning mechanism is provided at the center of the bottom of the shell, the positioning mechanism has a lead groove adapted to the first lead, so that when the core is installed in the shell, the positioning mechanism is inserted into the central through hole of the core rod for interference fit, and the first lead is adapted to be accommodated in the lead groove.

[0007] Furthermore, the positioning mechanism includes a positioning column and a supporting column. The positioning column is inserted into the central through hole of the core rod with interference fit, and the supporting column is fixedly connected to the bottom of the shell to support the bottom surface of the core.

[0008] Furthermore, the lead groove is opened along the side surface of the positioning column and the top surface of the supporting column, and is bent at the connection between the positioning column and the supporting column, so that the first lead wire passes through the top surface of the positioning column and passes through the side surface of the supporting column.

[0009] Furthermore, a first arc-shaped portion is provided at the connection between the positioning column and the supporting column so that the lead-wire groove is bent in an arc shape, and a second arc-shaped portion is provided at the bottom end of the core rod to match the first arc-shaped portion.

[0010] Furthermore, there are a plurality of lead grooves, which are evenly distributed along the circumferential direction of the positioning column and the supporting column.

[0011] Furthermore, a plurality of pressure columns are evenly distributed on the bottom of the top cover, so that when the top cover is sealed and installed above the core, the plurality of pressure columns respectively abut against the top surface of the core.

[0012] Furthermore, the film roll is formed by winding two stacked layers of metallized films, and a plurality of metal-plated areas are arranged side by side on the metallized film, and a screen band area is provided between two adjacent metal-plated areas, so that when the two layers of metallized films are stacked together, two adjacent metal-plated areas on the first metallized film are connected to each other through a metal-plated area of ​​the second metallized film, and the metal-plated areas at both ends of the first metallized film are electrically connected to the gold-sprayed layer respectively.

[0013] Furthermore, a plurality of metal blocks are arranged at intervals in the metal plating area, and two adjacent metal blocks are connected by a fuse.

[0014] Furthermore, the gold-sprayed layer is a zinc layer, the conductive metal wires of the first lead and the second lead are zinc wires, and the first lead and the second lead are respectively welded to the gold-sprayed layer at both ends of the film roll by zinc-spraying.

[0015] The beneficial effects of the utility model: the center-hole type film capacitor provided by the present application, by setting the center-hole at the center of the top cover, the lead terminal is sealed and connected in the center-hole, so that the first lead passes through the center through hole of the core rod and is electrically connected to the gold-sprayed layer at the bottom end of the film roll, and the second lead is directly electrically connected to the gold-sprayed layer at the top end of the film roll, thereby reducing the wiring length, and by setting a positioning mechanism at the bottom of the shell that is interference fit with the center through hole of the core rod to position and fix the core, avoiding deviation of the core installation position, ensuring that the core is centered in the center position of the shell, significantly improving the installation efficiency and installation effect, and the positioning mechanism has a lead groove that is compatible with the first lead, and the first lead passing through the center through hole of the core rod can be adapted and accommodated in the lead groove, effectively avoiding the formation of a gap between the positioning mechanism and the core rod, affecting the positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] Figure 2 It is a top view of the utility model.

[0018] Figure 3 for Figure 1 A local enlarged schematic diagram of point A in the middle.

[0019] Figure 4 It is a structural schematic diagram of the positioning mechanism of the utility model. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] like Figure 1-2As shown, the utility model provides a film capacitor, including a shell 1, a core 2 installed in the shell 1, a top cover 3 sealed on the shell 1, and a lead terminal 4 passing through the top cover 3, the core 2 is composed of a hollow core rod 21 and a film roll 22 wound on the core rod 21, both ends of the film roll 22 are provided with a gold spraying layer 23, the lead terminal 4 has a first lead 41 and a second lead 42, the lead terminal 4 is sealed and connected to the center hole at the center of the top cover 3, the first lead 41 passes through the central through hole of the core rod 21 and the gold spraying layer 23 at the bottom of the film roll 22 3 is electrically connected, the second lead 42 is electrically connected to the gold-sprayed layer 23 at the top of the film roll 22, and a positioning mechanism 5 is provided at the bottom center of the shell 1. The positioning mechanism 5 has a lead groove 51 adapted to the first lead 41, so that when the core 2 is installed in the shell 1, the positioning mechanism 5 is inserted into the central through hole of the core rod 21 for interference fit, so as to position and fix the core 2 and limit the displacement of the core 2 in the horizontal direction. At this time, the first lead 41 is adapted to be received in the lead groove 51, so as to avoid the formation of a gap between the positioning mechanism 5 and the core rod 21, thereby affecting the positioning accuracy.

[0022] like Figure 3-4 As shown, the positioning mechanism 5 includes a positioning column 52 and a support column 53. The positioning column 52 is inserted into the central through hole of the core rod 21 with an interference fit, and the support column 53 is fixedly connected to the bottom of the shell 1 to support the bottom surface of the core 2. The lead groove 51 is opened along the side of the positioning column 52 and the top surface of the support column 53, and is bent at the connection between the positioning column 52 and the support column 53, so that the first lead 41 passes through the top surface of the positioning column 52 and passes out from the side of the support column 53. The connection between the positioning column 52 and the support column 53 has a first arc portion 54, so that the lead groove 51 is bent in an arc shape, which is convenient for the routing of the first lead 41. The bottom end of the core rod 21 has a second arc portion 24 adapted to the first arc portion 54. There are multiple lead grooves 51, which are evenly distributed along the circumferential direction of the positioning column 52 and the support column 53. When the first lead 41 is arranged, it can pass through any lead groove 51, which further facilitates the routing of the first lead 41.

[0023] A plurality of pressure columns 31 are evenly distributed at the bottom of the top cover 3, so that when the top cover 3 is sealed and installed above the core 2, the plurality of pressure columns 31 respectively abut against the top surface of the core 2, further limiting the vertical displacement of the core 2. The pressure columns 31 are made of heat-conducting material to conduct heat from the core 2 for heat dissipation.

[0024] The film roll 22 is formed by winding two stacked layers of metallized films, and a plurality of metal-plated areas are arranged side by side on the metallized film, and a screen area is provided between two adjacent metal-plated areas, so that when the two layers of metallized films are stacked together, two adjacent metal-plated areas on the first metallized film are connected to each other through a metal-plated area of ​​the second metallized film, and the metal-plated areas at both ends of the first metallized film are electrically connected to the gold-sprayed layer 23 respectively. With such arrangement, the first metallized film is divided into a plurality of non-conductive parts through the screen band area, which is equivalent to forming a plurality of capacitor cores. After being laminated with the second metallized film, the metal-plated area on the second metallized film covers the screen band area of ​​the first metallized film, thereby connecting the parts of the first metallized film in series to form an internal series structure of the metallized film, which is equivalent to forming an internal series capacitor core. In this way, according to the voltage-dividing principle of the series circuit, the voltage is shared by the capacitor cores in series, and the load voltage of each capacitor core is reduced. The low voltage difference makes the capacitor more stable, which can effectively suppress the capacity attenuation of the product and extend the service life of the product.

[0025] Multiple metal blocks are arranged at intervals in the metal plating area, and two adjacent metal blocks are connected by fuses. The fuses are located on the edges of the metal blocks. By arranging fuses on both layers of metallized films, local fuses can be continuously blown to form isolation, which can effectively reduce product energy and achieve explosion-proof effects, thereby meeting both explosion-proof and life standards.

[0026] The gold-sprayed layer 23 is a zinc layer, and the conductive metal wires of the first lead 41 and the second lead 42 are zinc wires. The first lead 41 and the second lead 42 are respectively welded to the gold-sprayed layer 23 at both ends of the film roll 22 by spraying zinc. Since the materials used for the first lead 41, the second lead 42 and the gold-sprayed layer 23 are all pure zinc, the bonding degree between zinc and zinc is stronger than the bonding degree between zinc and tin. When the lead is welded by spraying pure zinc, the lead is embedded in the pure zinc environment and combined with the core 2, thereby improving the pulling force between the core 2 and the lead. Among them, spraying pure zinc is to short-circuit the two zinc wires of the lead with positive and negative charges, and blast the zinc into fine particles under a strong current, and spray it on the place where the lead contacts the zinc layer. No zinc spraying is required at other places, that is, a spraying point is formed.

[0027] The center-hole type film capacitor provided by the present application is characterized in that a center-hole is provided at the center of the top cover, and the lead terminal is sealed and connected in the center-hole, so that the first lead wire passes through the center through hole of the core rod and is electrically connected to the gold-sprayed layer at the bottom end of the film roll, while the second lead wire is directly electrically connected to the gold-sprayed layer at the top end of the film roll, thereby reducing the wiring length, and the core is positioned and fixed by providing a positioning mechanism that is interference-fitted with the center through hole of the core rod at the bottom of the shell, thereby avoiding deviation of the core installation position and ensuring that the core is centered in the center position of the shell, thereby significantly improving the installation efficiency and installation effect, and the positioning mechanism has a lead groove that is compatible with the first lead wire, and the first lead wire that passes through the center through hole of the core rod can be adapted and accommodated in the lead groove, thereby effectively avoiding the formation of a gap between the positioning mechanism and the core rod, thereby affecting the positioning accuracy.

[0028] The above contents are merely examples and explanations of the structure of the utility model. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the utility model or exceed the scope defined in the claims, they should all fall within the protection scope of the utility model.

Claims

1. A film capacitor, comprising a housing (1), a core (2) installed in the housing (1), a top cover (3) sealed on the housing (1), and a lead terminal (4) penetrating the top cover (3), wherein the core (2) is composed of a hollow core rod (21) and a film roll (22) wound on the core rod (21), both ends of the film roll (22) are provided with a gold spraying layer (23), and the lead terminal (4) has a first lead wire (41) and a second lead wire (42), characterized in that: The lead terminal (4) is sealed and connected to the center hole at the center of the top cover (3); the first lead (41) passes through the central through hole of the core rod (21) and is electrically connected to the gold-sprayed layer (23) at the bottom end of the film roll (22); the second lead (42) is electrically connected to the gold-sprayed layer (23) at the top end of the film roll (22); a positioning mechanism (5) is provided at the center of the bottom of the shell (1); the positioning mechanism (5) has a lead groove (51) adapted to the first lead (41), so that when the core (2) is installed in the shell (1), the positioning mechanism (5) is inserted into the central through hole of the core rod (21) for interference fit, and the first lead (41) is adapted to be received in the lead groove (51).

2. The film capacitor according to claim 1, characterized in that: The positioning mechanism (5) comprises a positioning column (52) and a support column (53). The positioning column (52) is inserted into the central through hole of the core rod (21) with interference fit, and the support column (53) is fixedly connected to the bottom of the shell (1) to support the bottom surface of the core (2).

3. The film capacitor according to claim 2, characterized in that: The lead groove (51) is opened along the side surface of the positioning column (52) and the top surface of the supporting column (53), and is bent at the connection between the positioning column (52) and the supporting column (53), so that the first lead (41) passes through the top surface of the positioning column (52) and passes out from the side surface of the supporting column (53).

4. The film capacitor according to claim 3, characterized in that: A first arc-shaped portion (54) is provided at the connection between the positioning column (52) and the supporting column (53) so as to make the lead wire groove (51) bend in an arc shape, and a second arc-shaped portion (24) matching the first arc-shaped portion (54) is provided at the bottom end of the core rod (21).

5. The film capacitor according to claim 4, characterized in that: There are a plurality of lead wire grooves (51) which are evenly distributed along the circumferential direction of the positioning column (52) and the supporting column (53).

6. The film capacitor according to claim 1, characterized in that: A plurality of pressure columns (31) are evenly distributed on the bottom of the top cover (3), so that when the top cover (3) is sealed and installed above the core (2), the plurality of pressure columns (31) respectively abut against the top surface of the core (2).

7. The film capacitor according to claim 1, characterized in that: The film roll (22) is wound by two stacked metallized films, with a plurality of metal-plated areas arranged side by side on the metallized films, and a screen area is provided between two adjacent metal-plated areas, so that when the two metallized films are stacked together, two adjacent metal-plated areas on the first metallized film are connected to each other through a metal-plated area of ​​the second metallized film, and the metal-plated areas at both ends of the first metallized film are electrically connected to the gold-sprayed layer (23) respectively.

8. The film capacitor according to claim 7, characterized in that: A plurality of metal blocks are arranged at intervals in the metal plating area, and two adjacent metal blocks are connected by fuses.

9. The film capacitor according to claim 1, characterized in that: The gold-sprayed layer (23) is a zinc layer, the conductive metal wires of the first lead (41) and the second lead (42) are zinc wires, and the first lead (41) and the second lead (42) are respectively welded to the gold-sprayed layer (23) at both ends of the film roll (22) by zinc-spraying.

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