A fully sealed waterproof structure of a sudden jump thermostat

Abstract

A fully sealed waterproof structure of a snap-action thermostat, with a convex ring, the first and second concave ring grooves on the outer wall of the positioning cylinder, a vertical groove and a plurality of evenly distributed positioning columns on the inner wall, a silicone sealing ring sleeved at a right angle in the first concave ring groove, the positioning cylinder seal is pressed into the metal outer cover, the snap-action thermostat is positioned at the central position in the positioning cylinder by a plurality of evenly distributed positioning columns, and its cover is closely connected with the long concave arc surface at the bottom of the metal outer cover in line and surface contact, and the inner cavity formed between the metal outer cover and the cover plate is filled with epoxy resin sealant. The fully sealed waterproof structure of the snap-action thermostat enables the snap-action thermostat to pass the rigorous cold and hot shock test, thereby ensuring that it can work long-term, reliably and stably in a harsh cold and hot cycle environment.

Description

Technical Field

[0001] The invention relates to the technical field of thermostat waterproof structures, and in particular to a fully sealed waterproof structure of a sudden jump type thermostat. Background Art

[0002] A fully enclosed snap-action thermostat is currently used in air-cooled frost-free refrigerators or air conditioner outdoor units as a heating compensation switch or automatic defrost control switch, and works in indoor and outdoor environments with frost, snow, and rain. It consists of a snap-action thermostat 1 with wires 1-3, a straight cylindrical positioning ring 3, a metal outer cover 2, a cover ring 4, and is sealed with epoxy resin sealant 7. Figure 1 The epoxy resin sealant is directly filled into the inner cavity formed between the inner wall of the metal cover 2 and the cover ring 4 through a plurality of vertically penetrating grooves arranged on the outer wall of the straight cylindrical positioning ring 3. After curing, the epoxy resin sealant adheres to the inner wall of the metal cover 2, the cover ring 4, part of the wire 1-3 and the metal cover 1-1 and the shell 1-2 of the jump-type thermostat 1, playing a sealing role. Figure 1 The structure of the snap-action thermostat is shown. Since the metal cover 2 and the metal cover 1-1 in the fully enclosed snap-action thermostat are made of steel, aluminum or copper, the thermal expansion coefficient is about (14-16)×10 -6 / ℃, the thermal expansion coefficient of the straight-tube positioning ring 3, the cover ring 4, the housing 1-2, and the outer jacket of the wire 1-3 made of plastic or rubber is about (60~90)×10 -6 / ℃, the thermal expansion coefficient of epoxy resin sealant 7 is about (55~70)×10 -6 / ℃, which overlaps or is very close to the thermal expansion coefficient of plastics, but differs by more than 4 times from the thermal expansion coefficient of metals such as steel and copper. Therefore, the above-mentioned fully enclosed snap-action thermostat cannot pass the thermal shock test, the test conditions of which are: 500 thermal shock tests are performed on the sample, the thermal cycle temperature range is -40℉~+200℉, and then immersed in water at room temperature for 7 days. The hot and cold shock test creates gaps between the metal outer cover 2 and the metal cover 1-1 and the epoxy resin sealant 7. In order to improve the sensitivity of the snap-action thermostat, an outer convex line is provided in the center of the outer surface of the copper cover 1-1, which is connected to the center of the arc-shaped bottom of the metal outer cover 2 in line-surface contact. Since the thermal expansion coefficients of the two materials differ by more than 4 times, a gap through which water can seep is created between the metal cover 1-1 and the epoxy resin sealant 7. Water can enter the inner cavity of the snap-action thermostat 1 along the gap between the inner wall of the metal outer cover 2 and the epoxy resin sealant 7, the gap between the outer surface of the metal cover 1-1 and the epoxy resin sealant 7, and the gap between the inner wall of the cover 1-1 and the plastic shell 1-2, until the moving and static contacts are short-circuited and fail. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a fully sealed waterproof structure of a snap-action thermostat, which can enable the snap-action thermostat to pass severe hot and cold shock tests. The test conditions are: subjecting the sample to 500 hot and cold shock tests, with a hot and cold cycle temperature range of -40℉ to +200℉, and then immersing it in water at room temperature for 7 days.

[0004] The technical solution proposed by the present invention is as follows:

[0005] A fully sealed and waterproof structure of a snap-action thermostat comprises a snap-action thermostat, a metal outer cover, a cover plate, a positioning cylinder and a silicone seal ring. A convex ring is provided in the middle of the outer wall of the positioning cylinder to form a first concave ring groove and a second concave ring groove. The inner wall of the positioning cylinder is symmetrically provided with two vertically penetrating grooves and a plurality of vertical positioning columns are evenly distributed at the lower part of the inner wall. The silicone seal ring is sleeved in the first concave ring groove of the positioning cylinder. The snap-action thermostat 1 is placed in the positioning cylinder. A metal outer cover is sleeved on the outside of the positioning cylinder so that the cover of the snap-action thermostat is closely connected with the long concave arc surface at the bottom of the metal outer cover in line and surface contact. The silicone seal ring is sealed and connected with the inner wall of the metal outer cover. A cover plate is provided at the opening of the metal outer cover. The inner cavity formed between the metal outer cover and the cover plate is filled with epoxy resin sealant.

[0006] The outer diameter of the silicone seal ring is greater than or equal to the inner diameter of the metal cover by 1 to 3 mm, and the inner diameter of the silicone seal ring is less than or equal to the bottom diameter of the first concave ring groove of the positioning cylinder by 2 to 5 mm. The jump-type thermostat is positioned by three or four positioning columns evenly distributed in the positioning cylinder and is connected to the center of the bottom of the metal cover for positioning contact. The outer wall of the metal cover is provided with a circle of evenly distributed concave points at the intersection of the convex ring corresponding to the positioning cylinder and the second concave ring groove. The metal cover is made of copper or steel, the cover is made of aluminum alloy or copper or steel, and the positioning cylinder, cover plate, and the jump-type thermostat shell are made of plastic.

[0007] Compared with the prior art, the present invention has the following significant effects:

[0008] Since the thermal expansion coefficient of epoxy resin sealant is roughly consistent with that of plastic and rubber, and differs from that of aluminum alloy, steel and copper by more than four times, when this product has undergone hot and cold shock tests, gaps through which water can seep will appear between the metal cover and the convex ring of the positioning cylinder, between the epoxy resin sealant, between the metal cover and the epoxy resin sealant, and between the metal cover and the plastic shell of the thermostat. Water from outside can enter the inner cavity of the shell along the junction of the metal cover and the cover plate → the inner wall of the metal cover → the surface of the cover → the junction of the cover and the plastic shell, thereby rendering the jump-type thermostat ineffective.

[0009] For this purpose, a silicone seal ring is provided between the metal cover and the first concave ring groove of the positioning cylinder. The outer diameter of the silicone seal ring is 1-3mm larger than the inner diameter of the metal cover, and its inner diameter is 2-5mm smaller than the bottom diameter of the first concave ring groove of the positioning cylinder. This is enough to block the path of water that may penetrate into the inner cavity of the thermostat after the thermal shock test, ensuring that it can work long-term, reliably and stably in such a harsh thermal cycle environment. Three or four vertical positioning columns are evenly arranged inside the positioning cylinder to position the jump-type thermostat and make the outer plane of the cover closely contact and connect with the long concave arc surface at the bottom of the metal cover, thereby improving the sensitivity of the jump-type thermostat. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The utility model is a structural schematic diagram of an existing fully enclosed sudden jump type temperature controller.

[0011] Figure 2 The utility model is a schematic diagram of a front and cross-sectional view of a fully sealed and waterproof structure of a sudden jump type thermostat of the present invention.

[0012] Figure 3 yes Figure 2 A schematic front view of the positioning cylinder shown.

[0013] Figure 4 yes Figure 3 Schematic top view of .

[0014] Explanation of the markings in the figure: 1. Snap-action thermostat; 1-1. Cover; 1-2 Shell; 1-3. Wire; 2. Metal cover; 2-1. Concave arc surface; 2-2. Concave point; 3. Straight cylindrical positioning ring; 4. Cover ring; 5. Positioning cylinder; 5-1. 1st concave ring groove; 5-2. 2nd concave ring groove; 5-3. Convex ring; 5-4. Groove; 5-5. Positioning column; 6. Silicone sealing ring; 7. Epoxy resin sealant; 8. Cover plate. DETAILED DESCRIPTION

[0015] The present invention is further described in detail by the following examples.

[0016] See also Figure 2 , Figure 3 , Figure 4As shown, a fully sealed waterproof structure of a snap-action thermostat comprises a snap-action thermostat 1, a metal cover 2, a cover plate 8, a positioning cylinder 5 and a silicone seal ring 6. A convex ring 5-3 is provided in the middle of the outer wall of the positioning cylinder 5, and a first concave ring groove 5-1 and a second concave ring groove 5-2 are formed. The inner wall of the positioning cylinder 5 is symmetrically provided with two vertically penetrating grooves 5-4 and a plurality of vertical positioning columns 5-5 are evenly distributed at the lower part of the inner wall. The silicone seal ring 6 is placed on the inner wall of the positioning cylinder 5. The first concave annular groove 5-1 of the positioning cylinder 5; the snap-action thermostat 1 is placed in the positioning cylinder 5, the positioning cylinder 5 is covered with a metal outer cover 2, and the cover 1-1 of the snap-action thermostat 1 is closely connected with the long concave arc surface 2-1 at the bottom of the metal outer cover 2 in line and surface contact, the silicone sealing ring 6 is sealed and connected with the inner wall of the metal outer cover 2, and a cover plate 8 is covered at the opening of the metal outer cover 2, and the inner cavity formed between the metal outer cover 2 and the cover plate 8 is filled with epoxy resin sealant 7.

[0017] The outer diameter of the silicone seal ring 6 is greater than or equal to the inner diameter of the metal cover 2 by 1 to 3 mm, and the inner diameter of the silicone seal ring 6 is less than or equal to the bottom diameter of the first concave ring groove 5-1 of the positioning cylinder 5 by 2 to 5 mm. The snap-action thermostat 1 is positioned by three or four positioning columns 5-5 evenly distributed in the positioning cylinder 5 and is connected to the center of the bottom of the metal cover 2 for positioning contact. The outer wall of the metal cover 2 is provided with a circle of evenly distributed concave points 2-2 at the intersection of the convex ring 5-3 and the second concave ring groove 5-2 corresponding to the positioning cylinder 5. The metal cover 2 is made of copper or steel, the cover 1-1 is made of aluminum alloy or copper or steel, and the positioning cylinder 5, the cover plate 8, and the snap-action thermostat housing 1-2 are made of plastic.

[0018] The convex ring 5-3 in the positioning cylinder 5 has two functions. One is to serve as a positioning device for the metal outer cover 2 to position the positioning cylinder 5. The other is to form a first concave annular groove 5-1 on the outside of the positioning cylinder 5, and to put a silicone sealing ring 6 at a right angle to the first groove 5-1 to ensure that the water seepage gap between the metal outer cover 2 from the middle of the inner wall to the bottom and the adjacent epoxy resin sealant 7 due to the harsh high and low temperature cycle environment is reliably blocked and sealed, so that the outside water cannot penetrate into the inner cavity of the jump type thermostat 1, thereby ensuring its long-term and reliable normal operation.

[0019] The two vertical grooves 5 - 4 arranged on the inner wall of the positioning cylinder 5 are used to allow the epoxy resin sealant 7 to be quickly and smoothly filled into the cavity from the middle to the bottom of the metal outer cover 2 when the epoxy resin sealant 7 is poured.

[0020] A circle of evenly distributed concave points 2-2 provided on the outer wall of the metal outer cover 2 at the intersection of the convex ring 5-3 of the positioning cylinder 5 and the second concave ring groove 5-2 is obtained by a dotting or rolling sealing process, and its function is to fix the positioning cylinder 5, the jump-type thermostat 1 and the metal outer cover 2 together, and to make the cover 1-1 of the jump-type thermostat 1 and the long concave arc surface 2-1 at the bottom of the metal outer cover 2 in close line and surface contact.

Claims

1. A fully sealed waterproof structure of a snap-action thermostat, comprising a snap-action thermostat (1), a metal cover (2), and a cover plate (8), characterized in that: A positioning cylinder (5) and a silicone seal ring (6) are also provided. A convex ring (5-3) is provided in the middle of the outer wall of the positioning cylinder (5), and a first concave ring groove (5-1) and a second concave ring groove (5-2) are formed. The inner wall of the positioning cylinder (5) is symmetrically provided with two vertically penetrating grooves (5-4) and a plurality of vertical positioning columns (5-5) are evenly distributed at the lower part of the inner wall. The silicone seal ring (6) is sleeved in the first concave ring groove (5-1) of the positioning cylinder (5); a sudden jump type temperature controller ( 1) is placed in a positioning cylinder (5), the positioning cylinder (5) is covered with a metal cover (2) and the cover (1-1) of the snap-action thermostat (1) is closely connected to the long strip concave arc surface (2-1) at the bottom of the metal cover (2) in line and surface contact, the silicone seal ring (6) is sealed to the inner wall of the metal cover (2), the opening of the metal cover (2) is covered with a cover plate (8), and the inner cavity formed between the metal cover (2) and the cover plate (8) is filled with epoxy resin sealant (7).

2. The fully sealed waterproof structure of the sudden jump thermostat according to claim 1, characterized in that: The outer diameter of the silicone seal ring (6) is 1 to 3 mm larger than the inner diameter of the metal cover (2), and the inner diameter of the silicone seal ring (6) is 2 to 5 mm smaller than the bottom diameter of the first concave annular groove (5-1) of the positioning cylinder (5).

3. The fully sealed waterproof structure of the sudden jump thermostat according to claim 1, characterized in that: The snap-action temperature controller (1) is positioned by three or four positioning columns (5-5) evenly distributed in the positioning cylinder (5) and is connected to the center of the bottom of the metal outer cover (2) in a positioning contact manner.

4. The fully sealed waterproof structure of the snap-action thermostat according to claim 1, characterized in that: The outer wall of the metal outer cover (2) is provided with a circle of evenly distributed concave points (2-2) at the intersection of the convex circular ring (5-3) corresponding to the positioning cylinder (5) and the second concave circular groove (5-2).

5. The fully sealed waterproof structure of the sudden jump thermostat according to claim 1, characterized in that: The metal outer cover (2) is made of copper or steel, the sealing cover (1-1) is made of aluminum alloy, copper or steel, and the positioning cylinder (5), the cover plate (8) and the shell (1-2) of the sudden temperature controller are made of plastic.

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