Double-protection thermal protector

Abstract

The utility model relates to a double-protection thermal protector, which comprises a shell with an opening and a temperature control structure, the temperature control structure is embedded in the shell through the opening, and two electrode ends of the temperature control structure are connected with connecting wires extending outwards from the opening. The temperature control structure comprises a movable contact assembly, a static contact assembly and a bimetal temperature sensing piece arranged between the movable contact assembly and the static contact assembly, the bimetal temperature sensing piece enables the movable contact assembly and the static contact assembly to be in contact or separated, and one electrode end of the movable contact assembly and one electrode end of the static contact assembly are directly and electrically connected with one connecting wire. The other electrode end of the moving contact assembly and the other electrode end of the static contact assembly are electrically connected with the other connecting wire through a low-melting-point electric conductor. According to the thermal protector, an automatic reset protector and a disposable protector are combined together, the production cost can be reduced, and the thermal protector has the advantages of being convenient to install, wide in application range and the like.

Description

Technical Field

[0001] The utility model relates to the field of thermal protectors, in particular to a thermal protector with double protection. Background Art

[0002] Thermal protectors are widely used in the automatic protection of household appliances, motors and electrical equipment, such as washing machine motors, air conditioner fan motors, transformers, ballasts, electric heating appliances, etc. Current thermal protectors use bimetallic strips as temperature sensing elements. When the appliance is working normally, the bimetallic strips are in a free state and the contacts are in a closed or disconnected state. When the temperature rises to the operating temperature value, the bimetallic strips are heated to produce internal stress and quickly operate, opening or closing the contacts, cutting off or connecting the circuit, thereby playing a role in thermal protection. When the temperature drops to the nominal temperature value, the contacts automatically close or disconnect and resume normal working state. However, as a disconnection mechanism, the bimetallic strips may fail and lack secondary protection. Therefore, it is necessary to improve and perfect the current thermal protectors to meet safety requirements. Summary of the invention

[0003] The utility model aims to provide a double-protection thermal protector with simple and reasonable structure, convenient installation and stable structure.

[0004] A double-protection thermal protector comprises a shell with an opening and a temperature control structure, wherein the temperature control structure is embedded in the shell through the opening, and two electrode ends of the temperature control structure are connected to connecting wires extending from the opening to the outside, the temperature control structure comprises a moving contact component, a stationary contact component and a bimetallic temperature-sensing piece arranged between the moving contact component and the stationary contact component, the bimetallic temperature-sensing piece causes the moving contact component to contact or separate from the stationary contact component, one electrode end of the moving contact component and the stationary contact component is directly electrically connected to one of the connecting wires, and the other electrode end of the moving contact component and the stationary contact component is electrically connected to the other connecting wire through a low-melting-point conductor.

[0005] The purpose of the utility model can also be solved by the following technical measures:

[0006] As a more specific solution, the moving contact assembly includes a metal base and a moving contact piece arranged above the metal base, the bimetallic temperature sensing piece is placed between the moving contact piece and the metal base, and the fixed ends of the bimetallic temperature sensing piece and the moving contact piece are riveted to one end of the metal base, and the other end of the metal base is provided with an electrode end.

[0007] As a further solution, the static contact assembly includes an insulating seat and a static contact piece, the insulating seat is connected to one end of the metal base close to the opening, the static contact piece is connected to the insulating seat, and one end of the static contact piece is elastically in contact with the movable end of the moving contact piece, and the other end of the static contact piece is electrically connected to the low-melting-point conductor through the electrode end.

[0008] As a further solution, the end of the metal base away from the opening is bent to form a folded edge, the fixed ends of the bimetallic temperature sensor and the moving contact piece are stacked in sequence and riveted on the folded edge, and the metal base is provided with a conical boss stretched upward, the height of the conical boss is equal to or close to the height of the folded edge, and the conical boss is held in the middle position of the bimetallic temperature sensor.

[0009] As a further solution, the length of the moving contact piece is greater than that of the bimetallic temperature sensor, and a downwardly stretched conical bulge is provided in the middle of the moving contact piece. The movable end of the bimetallic temperature sensor is pushed against the bottom of the conical bulge after being deformed by overheating.

[0010] As a further solution, a metal sheet is connected to the insulating seat by integral injection molding, one end of the metal sheet is exposed on the surface of the insulating seat to form a static contact sheet, and the other end of the metal sheet extends out of the insulating seat to form an electrode terminal.

[0011] As a further solution, the insulating seat is placed on top of the metal base, and a pair of pressing ears arranged on the left and right sides of the insulating seat are integrally extended from the metal base. The pressing ears are riveted to the upper surface of the insulating seat to connect the metal base and the insulating seat.

[0012] As a further solution, the insulating seat is provided with an insulating partition wall extending along the opening direction of the shell, at least one side of the insulating partition wall is in close contact with the inner wall of the shell, the insulating partition wall blocks between the two electrode ends, and the low-melting-point conductor is arranged on one side of the insulating partition wall.

[0013] As a further solution, a wire lead-out cavity is formed between the insulating partition wall and the shell, and the wire lead-out cavity is encapsulated with epoxy resin at least at an opening end close to the shell.

[0014] As a further solution, the low melting point conductor is coated with a layer of co-solvent.

[0015] The beneficial effects of the utility model are as follows:

[0016] The utility model discloses a double-protection thermal protector, which combines an automatic reset device with a disposable protector, can reduce production costs, and has the advantages of being easy to install and having a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the sectional structure of an embodiment of the utility model.

[0018] Figure 2 This is a schematic diagram of the cross-sectional structure of the thermal protector in the utility model.

[0019] Figure 3 It is a schematic diagram of the decomposed structure of the temperature control structure in the utility model.

[0020] Figure 4 It is a schematic diagram of the insulating seat structure in the utility model.

[0021] Figure 5 It is a schematic diagram of the cross-sectional structure of the low melting point conductor in the utility model. DETAILED DESCRIPTION

[0022] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0023] like Figures 1 to 5 As shown, a dual-protection thermal protector comprises a shell 1 with an opening and a temperature control structure 2, wherein the temperature control structure 2 is embedded in the shell 1 through the opening, and two electrode ends 201 of the temperature control structure 2 are connected with connecting wires 3 extending from the opening to the outside, the temperature control structure 2 comprises a moving contact component 4, a stationary contact component 5 and a bimetallic temperature-sensing piece 6 disposed between the moving contact component 4 and the stationary contact component 5, the bimetallic temperature-sensing piece 6 causes the moving contact component 4 to contact or separate from the stationary contact component 5, one electrode end 201 in the moving contact component 4 and the stationary contact component 5 is directly electrically connected to one of the connecting wires 3, and the other electrode end 201 in the moving contact component 4 and the stationary contact component 5 is electrically connected to the other connecting wire 3 through a low-melting-point conductor 7; this thermal protector combines automatic reset and disposable protectors together, can reduce production costs, and has the advantages of easy installation and a wide range of applications.

[0024] Specifically, the moving contact assembly 4 includes a metal base 41 and a moving contact piece 42 arranged above the metal base 41, the moving end of the moving contact piece 42 is provided with a moving contact 421, the bimetallic temperature-sensing piece 6 is placed between the moving contact piece 42 and the metal base 41, and the fixed ends of the bimetallic temperature-sensing piece 6 and the moving contact piece 42 are riveted to one end of the metal base 41, and the other end of the metal base 41 is provided with an electrode end 201.

[0025] The static contact assembly 5 includes an insulating seat 51 and a static contact piece 52. The insulating seat 51 is connected to one end of the metal base 41 that is close to the opening. The static contact piece 52 is connected to the insulating seat 51, and one end of the static contact piece 52 is elastically in contact with the movable end of the dynamic contact piece 42. The other end of the static contact piece 52 is electrically connected to the low-melting-point conductor 7 through the electrode end 201.

[0026] In normal use, the moving contact 421 of the moving contact piece 42 abuts against the stationary contact piece 52. When the product protected by the thermal protector exceeds the limit temperature, the automatically reset bimetallic temperature-sensing piece 6 starts to work, and the internal stress generated by the heat causes it to move quickly. The active end of the bimetallic temperature-sensing piece 6 bounces upward to push the moving contact piece 42 away from the stationary contact piece 52 to disconnect the circuit.

[0027] However, when the product protected by the thermal protector exceeds the limit temperature, the bimetallic temperature sensor 6 has an abnormal condition, resulting in circuit failure, and the low-melting-point conductor 7 of the secondary protection starts to work and melts due to the temperature, causing the circuit to be disconnected;

[0028] The end of the metal base 41 away from the opening is bent to form a folded edge 411, the fixed ends of the bimetallic temperature sensing piece 6 and the moving contact piece 42 are sequentially stacked and riveted on the folded edge 411, and the metal base 41 is provided with a tapered boss 412 stretched upward, the height of the tapered boss 412 is equal to or close to the height of the folded edge 411, and the tapered boss 412 is held against the middle position of the bimetallic temperature sensing piece 6;

[0029] The raised folded edge 411 sets the bimetallic temperature sensor 6 apart from the metal base 41 to prevent the heat of the metal base 41 from directly contacting and transferring to the bimetallic temperature sensor 6. In addition, the conical boss 412 supports the bimetallic temperature sensor 6 to prevent the bimetallic temperature sensor 6 from over-resetting.

[0030] The length of the moving contact piece 42 is greater than that of the bimetallic temperature-sensing piece 6, so that a distance is maintained between the bimetallic temperature-sensing piece 6 and the stationary contact piece 52, and a downwardly stretched conical convex bump 422 is provided in the middle of the moving contact piece 42, and the movable end of the bimetallic temperature-sensing piece 6 is pushed against the bottom of the conical convex bump 422 after being deformed by overheating; when the bimetallic temperature-sensing piece 6 generates internal stress due to heat, the conical convex bump 422 helps the bimetallic temperature-sensing piece 6 to push the movable end of the contact piece 42 to move.

[0031] A metal sheet is connected to the insulating seat 51 through integral injection molding, one end of the metal sheet is exposed on the surface of the insulating seat 51 to form a static contact sheet 52, and the other end of the metal sheet extends out of the insulating seat 51 to form an electrode end 201, so that the internal structure of the thermal protector is more compact, the static contact sheet 52 can be firmly connected to the insulating seat 51, and it plays an isolation role to prevent the static contact sheet 52 from approaching the metal base 41 or the housing 1 and causing creepage.

[0032] The insulating seat 51 mainly includes a rear seat 511 tightly matched with the shell 1 and a front seat 512 connected to the metal base 41. An island platform 513 is provided in the middle of the front seat 512. The static contact piece 52 is integrally arranged on the upper surface of the island platform 513, and a creepage groove 514 is provided between the island platform 513 and the front seat 512. The creepage groove 514 can increase the creepage distance of the static contact piece 52 and improve the safety of the thermal protector.

[0033] The insulating seat 51 is placed on top of the metal base 41. A pair of pressing ears 413 arranged on the left and right sides of the insulating seat 51 are integrally extended from the metal base 41. The pressing ears 413 are riveted to the upper surface of the insulating seat 51 to connect the metal base 41 and the insulating seat 51 to each other. The structure is simple, the connection is firm and stable, and it is easy to assemble and disassemble. It is suitable for use on an automated production line, so that structures made of two different materials can be connected.

[0034] The insulating seat 51 is provided with an insulating partition wall 515 extending along the opening direction of the outer shell 1. At least one side of the insulating partition wall 515 is in close contact with the inner wall of the outer shell 1. The insulating partition wall 515 blocks the two electrode ends 201. The low-melting-point conductor 7 is arranged on one side of the insulating partition wall 515, and the low-melting-point conductor 7 is arranged in the outer shell 1; the insulating partition wall 515 can increase the creepage distance between the two electrode ends 201 and improve the safety of the thermal protector.

[0035] A wire lead-out cavity 101 is formed between the insulating partition wall 515 and the shell 1 , and the wire lead-out cavity 101 is encapsulated with epoxy resin 8 at least at the opening end close to the shell 1 ; the opening of the shell 1 can be encapsulated to prevent liquid or foreign matter from entering the shell 1 .

[0036] The low melting point conductor 7 is wrapped with a layer of solvent 9, and the solvent 9 can be rosin.

[0037] The low melting point conductor 7 includes a diode, a tin alloy material or a copper alloy material. The above materials are prone to melting under relatively low temperature conditions. In this embodiment, the low melting point conductor 7 is preferably made of a tin alloy material;

[0038] The housing 1 is a hollow long flat structure and is made of plastic, ceramic or metal in one piece.

[0039] The above is a preferred embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. The utility model may have various changes and improvements without departing from the spirit and scope of the utility model, and these changes and improvements fall within the scope of the utility model to be protected, and the scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A dual-protection thermal protector, comprising a housing with an opening and a temperature control structure, wherein the temperature control structure is embedded in the housing through the opening, and two electrode ends of the temperature control structure are connected with connecting wires extending from the opening to the outside, characterized in that: The temperature control structure includes a moving contact component, a stationary contact component, and a bimetallic temperature-sensing piece placed between the moving contact component and the stationary contact component. The bimetallic temperature-sensing piece causes the moving contact component to contact or separate from the stationary contact component. One electrode end of the moving contact component and the stationary contact component is directly electrically connected to one of the connecting wires, and the other electrode end of the moving contact component and the stationary contact component is electrically connected to the other connecting wire through a low-melting-point conductor.

2. A dual protection thermal protector according to claim 1, characterized in that The moving contact assembly includes a metal base and a moving contact piece arranged above the metal base, the bimetallic temperature sensing piece is placed between the moving contact piece and the metal base, and the fixed ends of the bimetallic temperature sensing piece and the moving contact piece are riveted to one end of the metal base, and the other end of the metal base is provided with an electrode end.

3. A dual protection thermal protector according to claim 2, characterized in that The stationary contact assembly includes an insulating seat and a stationary contact piece. The insulating seat is connected to one end of the metal base close to the opening. The stationary contact piece is connected to the insulating seat, and one end of the stationary contact piece is elastically in contact with the movable end of the moving contact piece. The other end of the stationary contact piece is electrically connected to the low-melting-point conductor through the electrode end.

4. A dual protection thermal protector according to claim 2, characterized in that : The end of the metal base away from the opening is bent to form a folded edge, the fixed ends of the bimetallic temperature sensing piece and the moving contact piece are stacked in sequence and riveted on the folded edge, and the metal base is provided with a conical boss stretched upward, the height of the conical boss is equal to or close to the height of the folded edge, and the conical boss is held in the middle position of the bimetallic temperature sensing piece.

5. A dual protection thermal protector according to claim 2, characterized in that The moving contact piece is longer than the bimetallic temperature-sensing piece, and a conical convex bump stretched downward is provided in the middle of the moving contact piece. The movable end of the bimetallic temperature-sensing piece is pushed against the bottom of the conical convex bump after being deformed by overheating.

6. A dual protection thermal protector according to claim 3, characterized in that A metal sheet is connected to the insulating seat by integral injection molding, one end of the metal sheet is exposed on the surface of the insulating seat to form a static contact sheet, and the other end of the metal sheet extends out of the insulating seat to form an electrode terminal.

7. A dual protection thermal protector according to claim 3, characterized in that The insulating seat is placed on top of the metal base, and a pair of pressing ears are integrally extended from the metal base and arranged on the left and right sides of the insulating seat. The pressing ears are riveted to the upper surface of the insulating seat to connect the metal base and the insulating seat.

8. A dual protection thermal protector according to claim 3, characterized in that The insulating seat is provided with an insulating partition wall extending along the opening direction of the shell, at least one side of the insulating partition wall is in close contact with the inner wall of the shell, the insulating partition wall blocks between the two electrode ends, and the low-melting-point conductor is arranged on one side of the insulating partition wall.

9. A dual protection thermal protector according to claim 8, characterized in that A wire lead-out cavity is formed between the insulating partition wall and the shell, and the wire lead-out cavity is encapsulated with epoxy resin at least at the opening end close to the shell.

10. A dual protection thermal protector according to claim 1, characterized in that The low melting point conductor is coated with a layer of flux.

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