A method for measuring bimetal deflection

Abstract

The present invention belongs to the technical field of bimetallic performance testing, and specifically discloses a method for measuring the deflection of a bimetallic. The method for measuring the deflection of a bimetallic provided by the present invention places the bimetallic to be tested into a second heating box for heating, so that the bimetallic to be tested is bent and deformed by heat, simulating the scene when a product fails in actual application and the bimetallic to be tested is heated, and obtains the first deflection value of the bimetallic to be tested, and then applies a force to the bimetallic to be tested to obtain the second deflection value of the bimetallic to be tested, and obtains the actual deflection value of the bimetallic to be tested according to the first deflection value, the second deflection value, the first heating temperature and the weight of the measuring rod unit, so that the bimetallic to be tested is subjected to a force opposite to the direction of its bending by heat, simulating the resistance of the bimetallic to be tested in actual application, and then the accurate value of the deflection of the bimetallic to be tested can be obtained, thereby improving the accuracy of the deflection measurement of the bimetallic to be tested.

Description

Technical Field

[0001] The invention relates to the technical field of bimetallic performance testing, and in particular to a method for measuring bimetallic deflection. Background Art

[0002] Bimetallic elements are used as driving mechanisms in products such as circuit breakers, thermal overload relays, and AC motor starters to achieve the function of long-delay action protection characteristics. Bimetallic elements are made by heating and rolling two alloys with large differences in linear expansion coefficients. When heated, the bimetallic element bends from the high expansion layer (active layer) to the low expansion layer (passive layer). When the current is too large, the element moves due to "heat", pushing the product's action mechanism to switch the contact state, thereby achieving the purpose of protecting the circuit.

[0003] In actual product applications, the action mechanism in the product will exert a reaction force on the bimetal. The bending amount of the bimetal when it is bent by heat will be affected by the reaction force. Therefore, when testing the deflection of the bimetal, the bimetal to be tested needs to be subjected to a certain reaction force to simulate the actual application scenario in order to obtain the accurate value of the deflection of the bimetal to be tested. There is currently no such measurement method. Summary of the invention

[0004] The purpose of the present invention is to provide a method for measuring the deflection of a bimetal, which improves the accuracy of measuring the deflection of the bimetal to be measured and conforms to actual application scenarios.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A method for measuring bimetal deflection is applied to a bimetal deflection measuring device, the measuring device comprising a first heating box, a second heating box and a clamping device, the clamping device comprising a bimetal fixing unit, a displacement detection unit and a measuring rod unit, the bimetal fixing unit is used to fix the first end of the bimetal to be measured, the first end of the measuring rod unit is pressed against the second end of the bimetal to be measured, the displacement detection unit is connected to the second end of the measuring rod unit, the displacement detection unit is used to detect the displacement of the second end of the bimetal to be measured when it is heated and bent upward, the measuring method comprises:

[0007] S1. Put the bimetal to be tested into the first heating box, so that the bimetal to be tested is at the temperature of the product when it is working normally, and the heating temperature of the first heating box is the first heating temperature;

[0008] S2, moving the bimetal to be tested in the first heating box into the second heating box, so that the bimetal to be tested is at a temperature when a product failure occurs, the second end of the bimetal to be tested is bent upward along the first direction, and the heating temperature of the second heating box is a second heating temperature, which is greater than the first heating temperature;

[0009] S3, when the first bending change amount of the bimetal to be tested bending upward along the first direction is less than a first preset value, obtaining a first deflection value of the bimetal to be tested;

[0010] S4, applying a force downward in the first direction to the second end of the bimetal to be tested to obtain a second deflection value of the bimetal to be tested;

[0011] S5. Obtain an actual deflection value of the bimetal to be measured according to the first deflection value, the second deflection value, the second heating temperature and the weight of the measuring rod unit.

[0012] As an optional technical solution for the above-mentioned bimetal deflection measurement method, steps S1 to S5 are performed at least twice to obtain the actual deflection values ​​of at least two bimetals to be measured, and to determine whether the difference between the at least two actual deflection values ​​is within a preset range.

[0013] As an optional technical solution of the above-mentioned bimetal deflection measurement method, the actual deflection value in step S5 is obtained by the following formula:

[0014] Actual deflection value = first deflection value + first deflection compensation amount + second deflection compensation amount;

[0015] The first deflection compensation amount is obtained based on the second heating temperature and the first deflection value, and the second deflection compensation amount is obtained based on the first deflection value, the second deflection value, and the weight of the measuring rod unit.

[0016] As an optional technical solution of the above-mentioned bimetal deflection measurement method, the first deflection compensation amount is obtained according to the second heating temperature and the first deflection value and includes:

[0017] The first deflection compensation amount = the first deflection value × (the second heating temperature - 20°C) / (150°C - the second heating temperature).

[0018] As an optional technical solution of the above-mentioned bimetal deflection measurement method, the second deflection compensation amount is obtained according to the first deflection value, the second deflection value, and the weight of the measuring rod unit, including:

[0019] Obtaining, according to the weight of the measuring rod unit, a compensation displacement amount for causing the bimetal to bend downward when the measuring rod unit presses against the second end of the bimetal to be measured;

[0020] The second deflection compensation amount = ((first deflection value + compensation displacement) × 1.5 / 12 + weight of the measuring rod unit) × (first deflection value - second deflection value) / 0.98.

[0021] As an optional technical solution of the above-mentioned bimetal deflection measurement method, step S3 includes:

[0022] The first bending change amount of the bimetal to be measured is determined in each first preset time. If the first bending change amount of the bimetal to be measured is less than a first preset value, the first deflection value is obtained.

[0023] As an optional technical solution of the above-mentioned bimetal deflection measurement method, if the bimetal to be measured placed in the second heating box in step S4 is moved into the first heating box again, step S1 includes:

[0024] The bimetal to be tested is placed in the first heating box, so that the bimetal to be tested is at the temperature when the product is working normally. The second bending change of the bimetal to be tested is determined in each second preset time. If the second bending change of the bimetal to be tested is less than the second preset value, step S2 is executed.

[0025] As an optional technical solution of the above-mentioned method for measuring the deflection of the bimetal, if the bimetal to be measured is placed in the first heating box for the first time, step S1 includes:

[0026] The bimetal to be tested is placed in the first heating box and kept for a third preset time to reset the displacement detection unit to zero.

[0027] As an optional technical solution of the above-mentioned method for measuring the deflection of the bimetal, applying a force downward along the first direction to the second end of the bimetal to be measured in step S4 includes:

[0028] Applying a force to the measuring rod unit so that the measuring rod unit applies a force downward along a first direction to the second end of the bimetal to be measured.

[0029] As an optional technical solution for the above-mentioned bimetallic deflection measurement method, the first heating temperature is greater than 20°C and less than 30°C, and the second heating temperature is greater than 120°C and less than 140°C.

[0030] Beneficial effects of the present invention:

[0031] The method for measuring the deflection of a bimetal provided by the present invention comprises the following steps: placing a bimetal to be measured in a second heating box for heating, so that the bimetal to be measured is bent and deformed by heat, simulating a scenario in which a product fails in an actual application and the bimetal to be measured is heated, and obtaining a first deflection value of the bimetal to be measured, and then applying a force to the bimetal to be measured to obtain a second deflection value of the bimetal to be measured, and obtaining an actual deflection value of the bimetal to be measured according to the first deflection value, the second deflection value, the first heating temperature and the weight of a measuring rod unit, so that the bimetal to be measured is subjected to a force in a direction opposite to the bending direction thereof by heat, and the force comprises a force applied to the second end of the bimetal to be measured and a force applied to the bimetal to be measured by the measuring rod unit, simulating the resistance to which the bimetal is subjected in an actual application, and then obtaining an accurate value of the deflection of the bimetal to be measured, thereby improving the accuracy of the deflection measurement of the bimetal to be measured; in addition, the bimetal to be measured is first placed in the first heating box, simulating the temperature environment in which the bimetal to be measured is located when the product works normally in an actual application, thereby improving the accuracy of the first deflection value obtained after the bimetal to be measured is bent by heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of a bimetal deflection measuring device provided by an embodiment of the present invention;

[0033] Figure 2 It is a flow chart of a method for measuring bimetal deflection provided in an embodiment of the present invention.

[0034] In the figure:

[0035] 100. Bimetal to be tested;

[0036] 1. First heating box; 2. Second heating box; 3. Clamping device; 31. Bimetallic fixing unit; 32. Displacement detection unit; 33. Measuring rod unit. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0038] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0041] This embodiment provides a method for measuring bimetal deflection, which is applied to a device for measuring bimetal deflection. Figure 1 As shown, the measuring device includes a first heating box 1, a second heating box 2 and a clamping device 3. The clamping device 3 includes a bimetal fixing unit 31, a displacement detection unit 32 and a measuring rod unit 33. The bimetal fixing unit 31 is used to fix the first end of the bimetal 100 to be tested, the first end of the measuring rod unit 33 is pressed against the second end of the bimetal 100 to be tested, the displacement detection unit 32 is connected to the second end of the measuring rod unit 33, and the displacement detection unit 32 is used to detect the displacement of the second end of the bimetal 100 to be tested when it is heated and bent upward. The clamping device 3 can move up and down in the first direction to place the bimetal 100 to be tested in the first heating box 1 or the second heating box 2. The clamping device 3 can also move between the first heating box 1 and the second heating box 2 so that the bimetal 100 to be tested can be switched to the first heating box 1 and the second heating box 2 at different temperatures. The specific structure of the clamping device 3 and the structure for driving the clamping device 3 to move along the first direction and the second direction are not described in detail here.

[0042] like Figure 2 As shown, the method for measuring the bimetal deflection provided in this embodiment mainly includes the following steps:

[0043] S1, placing the bimetal 100 to be tested into the first heating box 1, so that the bimetal 100 to be tested is at the temperature of the product when it is working normally, and the heating temperature of the first heating box 1 is the first heating temperature;

[0044] S2, move the bimetal 100 to be tested in the first heating box 1 into the second heating box 2, so that the bimetal 100 to be tested is at a temperature when the product fails, the second end of the bimetal 100 to be tested is bent upward along the first direction, and the heating temperature of the second heating box 2 is a second heating temperature, which is greater than the first heating temperature;

[0045] S3, when the first bending change amount of the bimetal 100 to be tested bending upward along the first direction is less than a first preset value, obtaining a first deflection value of the bimetal 100 to be tested;

[0046] S4, applying a force downward in the first direction to the second end of the bimetal 100 to be tested, to obtain a second deflection value of the bimetal 100 to be tested;

[0047] S5. Obtain the actual deflection value of the bimetal 100 to be measured according to the first deflection value, the second deflection value, the second heating temperature and the weight of the measuring rod unit 33.

[0048] The bimetal deflection measurement method provided in this embodiment is to place the bimetal 100 to be tested in the second heating box 2 for heating, so that the bimetal 100 to be tested is bent and deformed by heat, simulating the scene when the product fails in actual application and the bimetal 100 to be tested is heated, and obtain the first deflection value of the bimetal 100 to be tested, and then apply force to the bimetal 100 to be tested to obtain the second deflection value of the bimetal 100 to be tested, and obtain the actual deflection value of the bimetal 100 to be tested according to the first deflection value, the second deflection value, the first heating temperature and the weight of the measuring rod unit 33, so that the bimetal 100 to be tested is subjected to the heating. The force is applied to the bimetal 100 to be tested in the opposite direction of its bending due to heat, and the force includes the force applied to the second end of the bimetal 100 to be tested and the force applied to the bimetal 100 to be tested by the measuring rod unit 33, which simulates the resistance of the bimetal 100 in actual applications, and then the accurate value of the deflection of the bimetal 100 to be tested can be obtained, thereby improving the accuracy of the deflection measurement of the bimetal 100 to be tested; in addition, the bimetal 100 to be tested is first placed in the first heating box 1 to simulate the temperature environment of the bimetal 100 to be tested when the product is working normally in actual applications, thereby improving the accuracy of the first deflection value obtained after the bimetal 100 to be tested is bent due to heat.

[0049] The product mentioned in this embodiment may be a circuit breaker, a thermal overload relay, an AC motor, etc., which is not specifically limited here.

[0050] In an practicable manner, if the bimetal 100 to be tested is sequentially placed in the first heating box 1 and the second heating box 2, the experimental measurement is terminated, and the measurement method includes the following steps:

[0051] S1. Place the bimetal 100 to be tested into the first heating box 1 for the first time and keep it for a third preset time to reset the displacement detection unit 32 to zero, implement the initialization operation, simulate the temperature environment of the bimetal 100 to be tested when the product works normally in actual applications, and improve the accuracy of obtaining the deflection value of the bimetal 100 to be tested in the next step.

[0052] S2, move the bimetal 100 to be tested in the first heating box 1 into the second heating box 2, so that the bimetal 100 to be tested is at a temperature when the product fails, the second end of the bimetal 100 to be tested is bent upward along the first direction, and the heating temperature of the second heating box 2 is a second heating temperature, which is greater than the first heating temperature;

[0053] S3, when the first bending change amount of the bimetal 100 to be tested bending upward along the first direction is less than a first preset value, obtaining a first deflection value of the bimetal 100 to be tested;

[0054] S4, applying a force downward in the first direction to the second end of the bimetal 100 to be tested, to obtain a second deflection value of the bimetal 100 to be tested;

[0055] S5. Obtain the actual deflection value of the bimetal 100 to be measured according to the first deflection value, the second deflection value, the second heating temperature and the weight of the measuring rod unit 33.

[0056] Finally, the bimetal 100 to be tested is taken out from the second heating box 2, and the experimental measurement is ended.

[0057] In another practicable manner, steps S1 to S5 are performed at least twice, the actual deflection values ​​of at least two bimetals 100 to be tested are obtained, and it is determined whether the difference between the at least two actual deflection values ​​is within a preset range, and the experimental measurement is repeated to determine the stability of the bimetal 100 to be tested, and then determine whether the bimetal 100 to be tested is qualified and meets the actual use requirements. The processing details of the bimetal 100 to be tested being placed in the first heating box 1 for the first time and entering the first heating box 1 for the second or third time are slightly different. The following is an example of performing steps S1 to S5 twice, as follows:

[0058] S1. Place the bimetal 100 to be tested into the first heating box 1 for the first time and keep it for a third preset time to reset the displacement detection unit 32 to zero, implement the initialization operation, simulate the temperature environment of the bimetal 100 to be tested when the product works normally in actual applications, and improve the accuracy of obtaining the deflection value of the bimetal 100 to be tested in the next step.

[0059] S2, move the bimetal 100 to be tested in the first heating box 1 into the second heating box 2, so that the bimetal 100 to be tested is at a temperature when the product fails, the second end of the bimetal 100 to be tested is bent upward along the first direction, and the heating temperature of the second heating box 2 is a second heating temperature, which is greater than the first heating temperature;

[0060] S3, when the first bending change amount of the bimetal 100 to be tested bending upward along the first direction is less than a first preset value, obtaining a first deflection value of the bimetal 100 to be tested;

[0061] S4, applying a force downward in the first direction to the second end of the bimetal 100 to be tested, to obtain a second deflection value of the bimetal 100 to be tested;

[0062] S5, obtaining the actual deflection value of the bimetal 100 to be measured according to the first deflection value, the second deflection value, the second heating temperature and the weight of the measuring rod unit 33;

[0063] S6, move the bimetal 100 to be tested in the second heating box 2 into the first heating box 1 again, so that the bimetal 100 to be tested is at the temperature when the product is working normally, do not apply force to the second end of the bimetal 100 to be tested, and judge the second bending change of the bimetal 100 to be tested in each second preset time. If the second bending change of the bimetal 100 to be tested is less than the second preset value, execute step S7 to restore the bimetal 100 to the initial state under the temperature environment when the product is working normally;

[0064] In this step, the second bending change amount of the bimetal 100 to be tested is determined in each second preset time. For example, the second bending change amount of the bimetal 100 to be tested is obtained in every 5 minutes. If the second bending change amount is less than 0.01 mm, step S7 is executed.

[0065] S7, moving the bimetal 100 to be tested in the first heating box 1 into the second heating box 2 again, so that the bimetal 100 to be tested is at the temperature when the product fails, the second end of the bimetal 100 to be tested is bent upward along the first direction, and the heating temperature of the second heating box 2 is the second heating temperature, which is greater than the first heating temperature;

[0066] S8, when the first bending change amount of the bimetal 100 to be tested bending upward along the first direction is less than a first preset value, obtaining a first deflection value of the bimetal 100 to be tested;

[0067] S9, applying a force downward in the first direction to the second end of the bimetal 100 to be tested, to obtain a second deflection value of the bimetal 100 to be tested;

[0068] S10 , obtaining the actual deflection value of the bimetal 100 to be measured according to the first deflection value, the second deflection value, the second heating temperature and the weight of the measuring rod unit 33 .

[0069] The two actual deflection values ​​are compared to judge the stability of the bimetal 100 to be tested, and then determine whether the bimetal 100 to be tested is qualified and meets the actual use requirements.

[0070] Optionally, the first heating temperature of the first heating box 1 is greater than 20°C and less than 30°C. Preferably, the first heating temperature may be 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C or 29°C.

[0071] The second heating temperature of the second heating box 2 is greater than 120°C and less than 140°C. Preferably, the second heating temperature may be 122°C, 125°C, 127°C, 130°C, 132°C, 135°C or 137°C.

[0072] Optionally, applying a force downward in the first direction to the second end of the bimetal 100 to be tested includes: applying a force to the measuring rod unit 33, so that the measuring rod unit 33 applies a force downward in the first direction to the second end of the bimetal 100 to be tested. The force is transmitted to the bimetal 100 to be tested by the measuring rod unit 33, so as to avoid the force directly acting on the bimetal 100 to be tested and damaging the bimetal 100 to be tested.

[0073] Optionally, in the above steps, when the first bending change amount of the bimetal 100 to be tested bending upward along the first direction is less than the first preset value, obtaining the first deflection value of the bimetal 100 to be tested specifically includes: determining the first bending change amount of the bimetal 100 to be tested in each first preset time, and if the first bending change amount of the bimetal 100 to be tested is less than the first preset value, obtaining the first deflection value to improve the accuracy of the deflection measurement of the bimetal 100 to be tested. Exemplarily, the first bending change amount of the bimetal 100 to be tested is obtained within every 5 minutes, and if the first bending change amount is less than 0.01 mm, the first deflection value is obtained.

[0074] In some embodiments, the actual deflection value of the bimetal 100 to be measured is obtained according to the first deflection value, the second deflection value, the second heating temperature and the weight of the measuring rod unit 33, and the actual deflection value = the first deflection value + the first deflection compensation amount + the second deflection compensation amount. Among them, the first deflection compensation amount is obtained according to the second heating temperature and the first deflection value, and the second deflection compensation amount is obtained according to the first deflection value, the second deflection value and the weight of the measuring rod unit 33. This calculation method offsets the influence of the second heating temperature, the measuring rod unit 33 and the applied force on the deflection measurement of the bimetal 100 to be measured, and improves the accuracy of the deflection measurement of the bimetal 100 to be measured.

[0075] Optionally, the first deflection compensation amount is obtained according to the second heating temperature and the first deflection value, including: first deflection compensation amount=first deflection value×(second heating temperature-20° C.) / (150° C.-second heating temperature).

[0076] The second deflection compensation amount is obtained according to the first deflection value, the second deflection value, and the weight of the measuring rod unit 33, including: obtaining, according to the weight of the measuring rod unit 33, a compensation displacement amount for bending the bimetal 100 to be tested downward when the measuring rod unit 33 presses against the second end of the bimetal 100 to be tested;

[0077] The second deflection compensation amount = ((first deflection value + compensation displacement) × 1.5 / 12 + weight of the measuring rod unit) × (first deflection value - second deflection value) / 0.98.

[0078] Exemplarily, the compensation displacement of the measuring rod unit 33 that causes the bimetal 100 to be bent downward is 0.55 mm, and the weight of the measuring rod unit 33 is 0.608 N. The numerical value can be substituted into the above formula for calculation.

[0079] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for measuring the deflection of a bimetal, applied to a device for measuring the deflection of a bimetal, the device comprising a first heating box (1), a second heating box (2) and a clamping device (3), the clamping device (3) comprising a bimetal fixing unit (31), a displacement detection unit (32) and a measuring rod unit (33), the bimetal fixing unit (31) being used to fix a first end of a bimetal (100) to be measured, the first end of the measuring rod unit (33) being pressed against a second end of the bimetal (100) to be measured, the displacement detection unit (32) being connected to the second end of the measuring rod unit (33), the displacement detection unit (32) being used to detect the displacement of the second end of the bimetal (100) to be measured when it is bent upward by heat, characterized in that: The measuring method comprises: S1, placing the bimetal (100) to be tested into the first heating box (1), so that the bimetal (100) to be tested is at a temperature when the product is working normally, and the heating temperature of the first heating box (1) is a first heating temperature; S2, moving the bimetal to be tested (100) in the first heating box (1) into the second heating box (2), so that the bimetal to be tested (100) is at a temperature at which a product failure occurs, the second end of the bimetal to be tested (100) is bent upward along the first direction, and the heating temperature of the second heating box (2) is a second heating temperature, which is greater than the first heating temperature; S3, when a first bending change amount of the bimetal to be tested (100) bending upward along a first direction is less than a first preset value, obtaining a first deflection value of the bimetal to be tested (100); S4, applying a force downward in a first direction to the second end of the bimetal (100) to be tested, to obtain a second deflection value of the bimetal (100) to be tested; S5. Obtaining an actual deflection value of the bimetal (100) to be measured according to the first deflection value, the second deflection value, the second heating temperature, and the weight of the measuring rod unit (33).

2. The method for measuring bimetallic deflection according to claim 1, characterized in that: Steps S1 to S5 are performed at least twice to obtain the actual deflection values ​​of at least two bimetals (100) to be tested, and to determine whether the difference between the at least two actual deflection values ​​is within a preset range.

3. The method for measuring bimetallic deflection according to claim 1, characterized in that: The actual deflection value in step S5 is obtained by the following formula: Actual deflection value = first deflection value + first deflection compensation amount + second deflection compensation amount; The first deflection compensation amount is obtained based on the second heating temperature and the first deflection value, and the second deflection compensation amount is obtained based on the first deflection value, the second deflection value, and the weight of the measuring rod unit (33).

4. The method for measuring bimetal deflection according to claim 3, characterized in that: The first deflection compensation amount is obtained according to the second heating temperature and the first deflection value and includes: The first deflection compensation amount = the first deflection value × (the second heating temperature - 20°C) / (150°C - the second heating temperature).

5. The method for measuring bimetal deflection according to claim 3, characterized in that: The second deflection compensation amount is obtained based on the first deflection value, the second deflection value, and the weight of the measuring rod unit (33), and includes: Obtaining, based on the weight of the measuring rod unit (33), a compensation displacement amount for causing the bimetal (100) to bend downward when the measuring rod unit (33) presses against the second end of the bimetal (100) to be measured; The second deflection compensation amount = ((first deflection value + compensation displacement) × 1.5 / 12 + weight of the measuring rod unit) × (first deflection value - second deflection value) / 0.

98.

6. The method for measuring bimetal deflection according to claim 1, characterized in that: Step S3 includes: The first bending change amount of the bimetal (100) to be tested is determined in each first preset time, and if the first bending change amount of the bimetal (100) to be tested is less than a first preset value, the first deflection value is obtained.

7. The method for measuring bimetal deflection according to claim 2, characterized in that: If the bimetal (100) to be tested placed in the second heating box (2) in step S4 is moved back into the first heating box (1), step S1 comprises: The bimetal to be tested (100) is placed in the first heating box (1), so that the bimetal to be tested (100) is at a temperature at which the product is operating normally, and the second bending change amount of the bimetal to be tested (100) is determined within each second preset time period; if the second bending change amount of the bimetal to be tested (100) is less than a second preset value, step S2 is executed.

8. The method for measuring bimetal deflection according to claim 1, characterized in that: If the bimetal (100) to be tested is placed in the first heating box (1) for the first time, step S1 comprises: The bimetal (100) to be tested is placed in the first heating box (1) and kept there for a third preset time, so that the displacement detection unit (32) is reset to zero.

9. The method for measuring bimetal deflection according to claim 1, characterized in that: Applying a force downward in a first direction to the second end of the bimetal (100) to be tested in step S4 comprises: A force is applied to the measuring rod unit (33), so that the measuring rod unit (33) applies a force downward along a first direction to the second end of the bimetal (100) to be measured.

10. The method for measuring bimetal deflection according to claim 1, characterized in that: The first heating temperature is greater than 20°C and less than 30°C, and the second heating temperature is greater than 120°C and less than 140°C.

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