A high-sensitivity snap-action thermostat

Abstract

A highly sensitive snap-action thermostat, with an annular groove on the upper bottom surface of the cover, a bimetallic disc in contact with the annular groove, a gasket matching and fixedly connected with the inner side wall of the cover, the upper bottom surface and the bottom surface of the annular edge of the bimetallic disc, forming an integrated component, and the inner side wall of the cover and the bottom surface of the gasket are respectively positioned and contacted with the outer side wall and the upper top surface of the guide frame. This highly sensitive snap-action thermostat fully meets the requirement that the snap-action thermostat must perform protection within 6 seconds of overheating; at the same time, it can ensure that the center of the bimetallic disc is always on the vertical line of the center of the cover in the initial state, during the over-temperature flipping process and after the flipping, ensuring that the action rod reaches the preset stroke, and the power is cut off cleanly and neatly. This product has good quality, a high pass rate, simple assembly and high production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of sudden jump type thermostats, in particular to a high-sensitivity sudden jump type thermostat. Background Art

[0002] With the application of new technologies, high-power "quartz glass film resistors" are widely used in drinking water machines and other water heating equipment, making the heating speed faster to meet people's increasingly high requirements for life and achieve hot water in 3 seconds. Based on this, higher requirements are placed on the protection of heating components. When the heating component is dry-burned due to lack of water, the heating rate of the heating component reaches 60-70℃ / s. If the heating power cannot be quickly cut off, it will cause a very serious safety accident. Therefore, higher requirements are placed on the sudden jump thermostat used for overheating protection. At present, most regulations in the industry require that the sudden jump thermostat must be activated within 6s to protect the heating component when dry-burning occurs. There is a sudden jump thermostat, which consists of an action rod 1, a first cover 2, a guide frame 3, a long rivet 4, a fixed contact plate 5, a shell 6, a first terminal 7-1, a second terminal 7-2, a moving contact bracket 8, a short rivet 9, a bimetallic disc 10, a fixed contact 11, a moving contact 12, and a bracket pressing block 13, see Figure 1 As shown. In this kind of sudden jump thermostat, since the heating element is only in direct contact with the first cover 2 and is in indirect contact with the bimetallic disc, a considerable portion of the heat of the heating element is directly transferred to the guide frame 3 and the housing 6, rather than directly transferred to the bimetallic disc 10. Therefore, it takes a long time to wait for the sudden jump thermostat to operate. Therefore, it cannot meet the requirement that the sudden jump thermostat must operate within 6 seconds of overheating protection.

[0003] The Chinese patent has disclosed a patent number of 201822268427.6, and its name is a sudden jump thermostat for quick-heating tubes, which is used in quick-heating heating tubes. The bimetallic temperature sensor 2 is circular, and its diameter is smaller than the opening diameter of the inner wall of the cover 1 and larger than the inner diameter of the annular ring block 12. The gasket 3 adopts a flat gasket or a V-shaped elastic gasket with a thickness of 0.05 to 1.0 mm to match the bimetallic temperature sensor of any temperature specification. It can be seen that the edge of the bimetallic temperature sensor 2 has a large degree of freedom in the space formed by the gasket 3 and the cover 1, and the contact connection between the bimetallic temperature sensor 2 and the bottom surface of the annular ring block 12 of the cover 1 is realized by flat gaskets or V-shaped elastic gaskets of different thicknesses, which have no positioning function. In this way, during the assembly of the thermostat, it cannot be guaranteed that the center of the bimetallic temperature sensor 2 is located on the vertical line of the center of the empty hole of the cover 1. When the circle of the bimetallic temperature sensor 2 When the center deviates from the vertical line of the center of the cover hole, after the cover 1 and the shell 8 are rolled and sealed, since the initial state of the bimetallic temperature-sensitive sheet 2 is a spherical surface that bulges upward, the edge portion that deviates from the vertical line will be clamped by the cover 1 and the gasket 3 first, and the edge portion of the bimetallic temperature-sensitive sheet 2 that is closer to the vertical line has more freedom of movement. In this way, when the heating element reaches the preset temperature value during operation, the bimetallic temperature-sensitive sheet 2 flips (jumps). At this time, it is not the center of the bimetallic temperature-sensitive sheet 2 that touches the top surface of the ceramic rod 10, but the concave spherical surface near the center of the circle, which shortens the action stroke of the ceramic rod 10, causing the moving and fixed contacts 7 and 5 to separate slowly and cause sparks to damage the contacts. In severe cases, the moving and fixed contacts cannot be separated and fail. It can be seen that the product quality is poor, the product qualification rate is not high, and the production efficiency is low. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a high-sensitivity snap-action temperature controller, by pre-assembling a cover, a bimetallic disc, and a gasket into an integrated component, ensuring that the center of the bimetallic disc and the center of the cover are located on the same vertical line and the plane of the bimetallic disc is perpendicular to the vertical line; when the thermostat is sealed, the integrated component can be conveniently positioned by a guide frame, thereby ensuring that the heat of the heating element is directly transferred to the bimetallic disc, and that the center of the bimetallic disc touches the actuating rod first when the action is flipped, so that the moving and fixed contacts can be separated quickly and cleanly; the product has good quality, high product qualification rate, and high production efficiency.

[0005] The technical solution proposed by the present invention is as follows:

[0006] A high-sensitivity snap-action temperature controller comprises an actuating rod, a cover, a guide frame, a long rivet, a fixed contact plate, a shell, a first terminal, a second terminal, a moving contact bracket, a short rivet, a bimetallic disc, a fixed contact, a moving contact and a bracket pressing block. The circular cover has a hole in the middle and is also provided with a gasket. The upper bottom surface of the cover is provided with an annular groove, and the bimetallic disc is matched and contacted with the annular groove. The gasket is matched and fixedly connected with the inner side wall, the upper bottom surface and the bottom surface of the annular edge of the bimetallic disc to form an integrated component; the integrated component is respectively positioned and contacted with the outer side wall and the upper top surface of the guide frame through the inner side wall of the cover and the bottom surface of the gasket, and is fixedly connected with the shell by rolling through the cover.

[0007] The sealing cover is fixedly connected to the bimetallic disc and the gasket by pre-pressing or welding. The gasket is made of aluminum or copper.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. This high-sensitivity snap-action thermostat is different from the existing common snap-action thermostat (see Figure 1 Compared with the structure shown in FIG. 1 , the metal cover 22 has the following differences: ① the metal cover 22 is provided with an annular groove 22-2 on its upper bottom surface 22-1; ② a gasket 14 is provided; ③ the bimetallic disc 10 is placed in the annular groove 22-2 of the cover, and the gasket 14 matches and is fixedly connected with the inner side wall 22-3 of the cover, the upper bottom surface 22-1 and the bottom surface of the annular edge of the bimetallic disc 10 to form an integrated component; ④ the integrated component is positioned and connected with the guide frame 3. The advantages and effects of the above structure are: ① ensuring that the entire annular edge of the bimetallic disc 10 is clamped and fixed by the gasket 14 and the cover 22, so that the center of the bimetallic disc 10 is always on the vertical line of the center of the cover 22 in its initial state, during the over-temperature flipping process and after the flipping, ensuring that the action rod 1 reaches the preset stroke, and the moving and fixed contacts can be separated quickly and cleanly. ② Since the integrated components are pre-assembled separately, in the final packaging stage of the thermostat, it is only necessary to insert the integrated components into the guide frame 3 and the housing 6 and position them with the guide frame 3, and then roll-seal them to become a highly sensitive snap-type thermostat product. This structure has good product quality, high pass rate, low assembly difficulty and high production efficiency.

[0010] 2. Since the bimetallic disc 10 is in the closed space formed by the cover 22 and the gasket 14, the thermostat can ensure direct and close contact between the bimetallic disc 10, the cover 22 and the gasket 14 at any installation angle, thereby avoiding the need for the temperature of the heating element to be transferred to the bimetallic disc 10 through the guide frame 3 whose mass is much greater than the gasket 14 and the air whose thermal conductivity is much smaller than the metal gasket 14. This effectively improves the temperature sensitivity of the thermostat, allowing the thermostat to act in time in an environment with a high heating rate and cut off the power supply to achieve the purpose of protection. According to the standard of the sudden jump thermostat currently equipped with a certain customer's direct drinking machine, a product with a disconnection temperature of 160°C is manufactured and installed on the heating element for dry burning test, which has a significant gain effect, see the table below:

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The utility model is a structural schematic diagram of an existing sudden jump type temperature controller.

[0013] Figure 2 The figure is a schematic structural diagram of a high-sensitivity snap-type temperature controller according to an embodiment of the present invention.

[0014] Figure 3 yes Figure 2 The structure diagram of the bimetallic disc 10, the cover 22 and the gasket 14 forming an integrated component is shown.

[0015] Figure 4 yes Figure 2 A schematic structural diagram of the gasket 14 is shown.

[0016] Figure 5 yes Figure 2 A schematic structural diagram of the bimetallic disc 10 is shown.

[0017] Figure 6 yes Figure 2 A schematic structural diagram of the cover 22 is shown.

[0018] Explanation of the markings in the figure: 1. actuating rod; 2. first cover; 3. guide frame; 4. long rivet; 5. fixed contact plate; 6. housing; 7-1. first terminal; 7-2. second terminal; 8. moving contact bracket; 9. short rivet; 10. bimetallic disc; 11. fixed contact; 12. moving contact; 13. bracket pressure block; 14. gasket; 22. cover; 22-1. bottom surface; 22-2. annular groove; 22-3. inner wall. DETAILED DESCRIPTION

[0019] The present invention is further described in detail by the following examples.

[0020] See also Figure 2 to Figure 6As shown, a high-sensitivity snap-action thermostat includes an actuating rod 1, a cover 22, a guide frame 3, a long rivet 4, a fixed contact plate 5, a housing 6, a first terminal 7-1, a second terminal 7-2, a moving contact bracket 8, a short rivet 9, a bimetallic disc 10, a fixed contact 11, a moving contact 12 and a bracket pressing block 13. The circular cover 2 has a hole in the middle and is also provided with a gasket 14. The upper bottom surface 22-1 of the cover 22 is provided with an annular groove 22-2. The bimetallic disc 10 is matched and contacted with the annular groove 22-2, and the gasket 14 is matched and fixedly connected with the inner wall 22-3 of the cover 22, the upper bottom surface 22-1 and the bottom surface of the annular edge of the bimetallic disc 10 to form an integrated component; the integrated component is positioned and contacted with the outer wall and the upper top surface of the guide frame 3 through the inner wall 22-3 of the cover 22 and the bottom surface of the gasket 14, and is fixedly connected with the shell 6 by rolling through the cover 22.

[0021] The sealing cover 22 is fixedly connected to the bimetallic disc 10 and the gasket 14 by pre-pressing or welding. The gasket 14 is made of aluminum or copper.

Claims

1. A high-sensitivity snap-action thermostat, comprising an actuating rod (1), a cover (22), a guide frame (3), a long rivet (4), a fixed contact plate (5), a housing (6), a first terminal (7-1), a second terminal (7-2), a movable contact support (8), a short rivet (9), a bimetallic disc (10), a fixed contact (11), a movable contact (12) and a support block (13), wherein a circular cover (22) has a hole in the middle, and is characterized in that: A gasket (14) is also provided. The upper bottom surface (22-1) of the cover (22) is provided with an annular groove (22-2). The bimetallic disc (10) is matched and contacted with the annular groove (22-2). The gasket (14) is matched and fixedly connected with the inner side wall (22-3), the upper bottom surface (22-1) and the bottom surface of the annular edge of the bimetallic disc (10) respectively. The cover (22), the bimetallic disc (10) and the gasket (14) form an integrated component. The integrated component is respectively connected to the outer wall and upper surface of the guide frame (3) in a positioning contact manner through the inner side wall (22-3) of the cover (22) and the bottom surface of the gasket (14), and is fixedly connected to the shell (6) by rolling through the cover (22).

2. The high-sensitivity snap-action thermostat according to claim 1, characterized in that: The sealing cover (22), the bimetallic disc (10) and the gasket (14) are fixedly connected by a pre-pressing method or a welding method.

3. The high-sensitivity snap-action thermostat according to claim 1, characterized in that: The gasket (14) is made of aluminum or copper.

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