Temperature characteristic detection method of thermal switch

Abstract

The present invention discloses a method for detecting the temperature characteristics of a thermal switch. The method comprises providing five oil tanks, namely, upper and lower limit oil tanks for operation, upper and lower limit oil tanks for reset, and a detection oil tank. The oil temperature in the detection oil tank is 15 to 25°C lower than the lower limit temperature for operation. The thermal switch is placed in the lower limit oil tank and held at a constant temperature for 5 to 8 minutes. The thermal switch is placed in the detection oil tank. If a test contact is disconnected, the first batch of qualified thermal switches are placed in the upper limit oil tank and held at a constant temperature for 5 to 8 minutes. The qualified thermal switches are removed and placed in the upper limit oil tank and held at a constant temperature for 5 to 8 minutes. The thermal switch is removed and placed in the detection oil tank. If a test contact is disconnected, the second batch of qualified thermal switches are placed in the lower limit oil tank and held at a constant temperature for 5 to 8 minutes. A conductive probe is then used to touch two terminals of the thermal switch. If the test contact is closed, the temperature characteristics test is passed; if the contact is disconnected, the temperature characteristics test is failed. The method has high detection reliability and low labor intensity for operators.

Description

Technical Field

[0001] The present invention relates to a method for detecting the product quality of a thermal switch, in particular to a method for detecting the temperature characteristics of a thermal switch. Background Art

[0002] A thermal switch consists of an open-bottomed housing, a baseplate mounted on the bottom of the housing, and a bimetallic strip mounted within the sealed chamber formed by the housing and baseplate. The baseplate typically has two terminals. When power is applied to the thermal switch through the terminals, overcurrent or overtemperature conditions trigger the thermal switch to open its contacts, disconnecting the power supply. Once the current and temperature return to normal, the thermal switch resets, closing the contacts and reconnecting the power supply. Thermal switches have an operating temperature range, such as 100°C to 120°C, with 100°C being the lower operating limit and 120°C being the upper operating limit. They also have a reset temperature range, such as 60°C to 70°C, with 60°C being the lower reset limit and 70°C being the upper reset limit. The thermal switch disconnects the power supply at operating temperatures between 100°C and 120°C, disconnecting the power supply at reset temperatures between 60°C and 70°C. Thermal switches are often installed inside electrical equipment, such as compressors, to protect the equipment.

[0003] As an electrical accessory with overtemperature protection and automatic reset upon cooling, thermal switches possess these essential features. Screening for these features is crucial during the manufacturing process. Existing methods for testing the temperature characteristics of thermal switches involve installing four oil tanks: a lower limit oil tank for operation, an upper limit oil tank for operation, a lower limit oil tank for reset, and an upper limit oil tank for reset. A conductive probe is then placed in each tank to touch the two terminals of the thermal switch. The on / off state of the terminals is then measured to determine if the thermal switch meets the requirements. This testing method suffers from two drawbacks: First, because each time the conductive probe is tested in each tank, the thermal switch is exposed to an environment close to or equal to its operating or reset temperature. Any slight contact with the conductive probe could cause the switch to prematurely operate or reset, leading to misjudgments and significantly reducing test reliability. Second, because four tests are performed in four tanks, not only is the operator's workload high, but the number of conductive probe touches is also high, further reducing test reliability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for detecting the temperature characteristics of a thermal switch which can not only reduce the labor intensity of operators but also greatly improve the detection reliability.

[0005] To solve the above technical problems, the present invention adopts a method for detecting the temperature characteristics of a thermal switch, wherein a plurality of thermal switches are detected simultaneously, comprising the following steps:

[0006] Step 1: Set up five oil tanks, namely, an action lower limit oil tank, an action upper limit oil tank, a reset lower limit oil tank, a reset upper limit oil tank, and a detection oil tank. The oil temperature in the action lower limit oil tank is equal to the action lower limit temperature of the thermal switch, the oil temperature in the action upper limit oil tank is equal to the action upper limit temperature of the thermal switch, the oil temperature in the reset lower limit oil tank is equal to the reset lower limit temperature of the thermal switch, the oil temperature in the reset upper limit oil tank is equal to the reset upper limit temperature of the thermal switch, and the oil temperature in the detection oil tank is 15-25°C lower than the action lower limit temperature of the thermal switch and higher than the reset upper limit temperature of the thermal switch.

[0007] Step 2: Place all thermal switches into the oil tank with lower action limit and keep the temperature constant for 5 to 8 minutes;

[0008] Step 3: Take out the thermal switches after constant temperature in the lower limit oil tank, put them into the test oil tank, use a conductive probe to touch the two terminals of each thermal switch, and test the thermal switches. If the contacts are open, they are qualified thermal switches in the first batch, and if the contacts are closed, they are unqualified thermal switches.

[0009] Step 4: Place the first batch of qualified thermal switches obtained in step 3 into the upper limit oil tank and keep the temperature constant for 5 to 8 minutes;

[0010] Step 5: Take out the first batch of qualified thermal switches after constant temperature in the action upper limit oil tank, and directly put them into the reset upper limit oil tank, and keep constant temperature for 5 to 8 minutes;

[0011] Step 6: After resetting the constant temperature in the upper limit oil tank, take out the first batch of qualified thermal switches and place them in the test oil tank. Use a conductive probe to touch the two terminals of each thermal switch. If the contacts of the thermal switches are closed, they are qualified thermal switches of the second batch. If the contacts are open, they are unqualified thermal switches.

[0012] Step 7: Place the second batch of qualified thermal switches obtained in step 6 into the reset lower limit oil tank. After maintaining the temperature for 5 to 8 minutes, use a conductive probe to touch the two terminals of each thermal switch to test the temperature characteristics. If the thermal switch contacts are closed, it means all the thermal switches have passed the temperature characteristic test. If the contacts are open, it means the thermal switches are unqualified.

[0013] As a preferred embodiment of the present invention, the oil in the oil tank is silicone oil, and the temperature of the oil in the detection oil tank is 20° C. lower than the lower limit temperature of the thermal switch.

[0014] After adopting the above method, the present invention has the following beneficial effects:

[0015] The oil temperature in the detection oil tank of the present invention is much lower than the lower limit temperature of the thermal switch, and at the same time higher than the upper limit temperature of the reset of the thermal switch. When the thermal switch is touched by the conductive probe in this detection oil tank environment, it will not misjudge the action or reset, thereby greatly reducing the misjudgment rate and significantly improving the reliability of product detection.

[0016] The present invention adopts only three detections, abandoning the four detections adopted in the prior art, reducing the number of detections, which not only reduces the labor intensity of the operator, but also reduces the number of detection touches between the conductive probe and the thermal switch, further improving the detection reliability of the product.

[0017] The present invention is provided with a detection oil tank, which makes the temperature characteristic detection environment of the thermal switch more reasonable, avoiding the problem that any slight touch of the conductive probe may cause the switch to operate or reset prematurely due to the thermal switch being in an environment close to its action or reset temperature, thereby causing misjudgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0019] Figure 1 This is a structural schematic diagram of the five oil tanks in the present invention.

[0020] Figure 2 for Figure 1 Schematic top view of .

[0021] Figure 3 This is a structural diagram of the thermal switch in the present invention. DETAILED DESCRIPTION

[0022] See also Figures 1 to 3 In order to improve the reliability of temperature characteristic detection of thermal switch A, the present invention adopts a temperature characteristic detection method of thermal switch A. A plurality of thermal switches A, for example 100, are detected simultaneously. Specifically, the method includes the following steps:

[0023] Step 1: Set up five oil tanks, namely, action lower limit oil tank 1, action upper limit oil tank 2, reset lower limit oil tank 3, reset upper limit oil tank 4 and detection oil tank 5. In the present invention, the oil in the oil tank is preferably silicone oil. The oil temperature in the action lower limit oil tank 1 is equal to the action lower limit temperature of the thermal switch, the oil temperature in the action upper limit oil tank 2 is equal to the action upper limit temperature of the thermal switch, the oil temperature in the reset lower limit oil tank 3 is equal to the reset lower limit temperature of the thermal switch, the oil temperature in the reset upper limit oil tank 4 is equal to the reset upper limit temperature of the thermal switch, and the oil temperature in the detection oil tank 5 is 15-25°C lower than the action lower limit temperature of the thermal switch. Preferably, the oil temperature in the detection oil tank 5 is 20°C lower than the action lower limit temperature of the thermal switch and higher than the reset upper limit temperature of the thermal switch.

[0024] Step 2: Place all thermal switches A into the lower limit oil tank 1, without testing, and keep the temperature constant for 5 to 8 minutes;

[0025] Step 3: Take out the thermal switches A after constant temperature in the lower limit oil tank 1 and place them in the test oil tank 5. Use a conductive probe to touch the two terminals of each thermal switch A. Test the thermal switches. If the contacts are open, they are the first batch of qualified thermal switches, i.e., the thermal switches with qualified lower limit temperature. If the contacts are closed, they are unqualified.

[0026] Step 4: Place the first batch of qualified thermal switches obtained in step 3 into the upper limit oil tank 2 without testing and keep the temperature constant for 5 to 8 minutes;

[0027] Step 5: Take out the first batch of qualified thermal switches after constant temperature in the action upper limit oil tank 2, and directly put them into the reset upper limit oil tank 4 without testing, and keep the temperature constant for 5 to 8 minutes;

[0028] Step 6: After the thermostat is set in the reset upper limit oil tank 4, the first batch of qualified thermal switches are taken out and placed in the test oil tank 5. A conductive probe is used to touch the two terminals of each thermal switch A. The test thermal switches are closed if the contacts are closed, which are qualified thermal switches in the second batch. The thermal switches are open if the contacts are unqualified. This step detects the thermal switches with unqualified action upper limit temperature and unqualified reset upper limit temperature at one time.

[0029] Step 7: Place the second batch of qualified thermal switches obtained in Step 6 into the reset lower limit oil tank 3. After maintaining the temperature for 5 to 8 minutes, use a conductive probe to touch the two terminals of each thermal switch A to test the temperature characteristics. If the thermal switches are closed, they are qualified thermal switches. If the contacts are open, they are unqualified thermal switches.

[0030] After trial use, the temperature characteristic detection method of the present invention has high detection reliability of the thermal switch. Compared with the existing technology, the present invention greatly reduces the misjudgment rate, and the labor intensity of the operator is low, achieving good results.

Claims

1. A method for detecting the temperature characteristics of a thermal switch, wherein a plurality of thermal switches are detected simultaneously, characterized in that: The following steps are involved: The first step is to set five oil tanks, namely, an action lower limit oil tank (1), an action upper limit oil tank (2), a reset lower limit oil tank (3), a reset upper limit oil tank (4) and a detection oil tank (5). The oil temperature in the action lower limit oil tank (1) is equal to the action lower limit temperature of the thermal switch, the oil temperature in the action upper limit oil tank (2) is equal to the action upper limit temperature of the thermal switch, the oil temperature in the reset lower limit oil tank (3) is equal to the reset lower limit temperature of the thermal switch, the oil temperature in the reset upper limit oil tank (4) is equal to the reset upper limit temperature of the thermal switch, and the oil temperature in the detection oil tank (5) is 15 to 25°C lower than the action lower limit temperature of the thermal switch and higher than the reset upper limit temperature of the thermal switch. Step 2: Place all thermal switches into the lower limit oil tank (1) and keep the temperature constant for 5 to 8 minutes; Step 3: Take out the thermosensitive switches after constant temperature in the action lower limit oil tank (1) and put them into the detection oil tank (5). Use a conductive probe to touch the two terminals of each thermosensitive switch. Test the thermosensitive switches. The thermosensitive switches with open contacts are qualified in the first batch, and the thermosensitive switches with closed contacts are unqualified. Step 4: Place the first batch of qualified thermal switches obtained in step 3 into the upper limit oil tank (2) and keep the temperature constant for 5 to 8 minutes; Step 5: Take out the first batch of qualified thermal switches after constant temperature in the action upper limit oil tank (2), and directly put them into the reset upper limit oil tank (4) and keep constant temperature for 5 to 8 minutes; Step 6: Take out the first batch of qualified thermal switches after the temperature in the reset upper limit oil tank (4) is constant, and put them into the test oil tank (5). Use a conductive probe to touch the two terminals of each thermal switch. Test the thermal switches. If the contacts are closed, they are qualified thermal switches of the second batch. If the contacts are open, they are unqualified thermal switches. Step 7: Place the second batch of qualified thermal switches obtained in step 6 into the reset lower limit oil tank (3). After maintaining the temperature for 5 to 8 minutes, use a conductive probe to touch the two terminals of each thermal switch to test the temperature characteristics. If the thermal switch contacts are closed, all the thermal switches are qualified. If the contacts are open, they are unqualified.

2. The method for detecting the temperature characteristics of a thermal switch according to claim 1, wherein: The oil in the oil tank is silicone oil, and the oil temperature in the detection oil tank (5) is 20°C lower than the lower limit temperature of the thermal switch.

Images