High-efficiency clamping tool for resistance test of lead-type PTC (Positive Temperature Coefficient) thermistor
By designing a pressure clamping device to quickly clamp multiple leaded PTC thermistors, the problems of low efficiency and mechanical damage in traditional testing methods are solved, and efficient and uniform resistance testing is achieved.
Patent Information
- Application Number
- CN202422763691.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-11-13
AI Technical Summary
Traditional leaded PTC thermistor resistance testing methods are inefficient and can easily cause mechanical damage to the leads.
A pressure clamping device comprising a clamping base plate, a clamping top plate, and a metal sheet is designed. By rotating the clamping base plate, the leads of multiple leaded PTC thermistors are pressed into the groove of the metal sheet and fixed with clamping screws, achieving fast and efficient clamping and avoiding mechanical damage.
It enables rapid and efficient clamping of multiple leaded PTC thermistors, ensuring uniform heating, protecting the product appearance, and improving testing efficiency.
Smart Images
Figure CN223551795U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a fixture for testing the resistance of PTC thermistors, and more particularly to a high-efficiency clamping fixture for testing the resistance of leaded PTC thermistors. Background Technology
[0002] PTC (Positive Temperature Coefficient) thermistors are a type of temperature-sensitive semiconductor resistor. Above a certain temperature, their resistance increases in a stepwise manner with increasing temperature. They are commonly used in electronic circuits for temperature measurement, temperature control, temperature compensation, surge suppression, and heating, and their applications cover aerospace, aviation, satellite, electronics, and weaponry.
[0003] A leaded PTC thermistor is a PTC thermistor with two electrodes led out through leads at both ends. It mainly consists of leads, a chip, and a glass shell. Its structural features are: 1. Fully sealed structure with glass encapsulation, resulting in high resistance stability; 2. Fast thermal response; 3. Small size and light weight; 4. High temperature measurement accuracy.
[0004] After production or testing, PTC thermistors require resistance testing. By comparing and calculating the resistance values under different temperature conditions, the performance of the resistor can be determined. Because PTC thermistors have very high sensitivity, the stability of the ambient temperature is strictly required when testing their resistance. The required temperature deviation is ±0.01℃, and the medium used to maintain this temperature environment is special silicone oil.
[0005] The traditional method for testing the resistance of leaded PTC thermistors involves clamping multiple PTC thermistors one by one onto a test fixture using leads. The fixture is then placed at the opening of an oil bath filled with silicone oil. The oil level is adjusted so that the PTC thermistors are submerged to a certain depth. This is maintained in the silicone oil at a specific temperature for 10-20 minutes, after which the resistance of each thermistor is measured sequentially. This traditional method has the following drawbacks: because the test fixture needs to clamp each PTC thermistor individually, the clamping speed is slow and inefficient, and it is prone to mechanical damage to the PTC thermistor leads. Utility Model Content
[0006] The purpose of this invention is to provide a high-efficiency clamping fixture for testing the resistance value of leaded PTC thermistors, which can quickly press-fit and install multiple leaded PTC thermistors, in order to solve the above-mentioned problems.
[0007] This utility model achieves the above objectives through the following technical solutions:
[0008] A high-efficiency clamping fixture for resistance testing of leaded PTC thermistors includes a horizontal fixture base plate and a horizontal fixture top plate. The horizontal dimension of the fixture base plate is smaller than that of the fixture top plate. The lower ends of multiple vertical columns are connected to the fixture base plate, and the upper ends of the multiple vertical columns are connected to the fixture top plate. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors also includes a pressure clamping device, which includes a clamping base plate, a clamping top plate, and a metal sheet. The horizontal clamping top plate is mounted on the fixture base plate. Below the clamping top plate, one end of the clamping bottom plate is rotatably connected to one end of the clamping top plate. Both the clamping bottom plate and the clamping top plate have vertically corresponding and through-holes. On the underside of the clamping top plate, on opposite sides of its through-holes, are multiple upwardly recessed upper strip-shaped grooves. Each upper strip-shaped groove contains a metal sheet of a corresponding shape. The other end of the clamping bottom plate is connected to the other end of the clamping top plate by a clamping screw. All the metal sheets are led to the tooling top plate via wires. Preferably, the upper strip-shaped groove is an arc-shaped groove with a radial arc cross-section. This ensures the metal sheet is strip-shaped with an arc-shaped radial cross-section, allowing for a tight fit with the upper strip-shaped groove and facilitating the placement of the leads of the leaded PTC thermistor.
[0009] Preferably, to facilitate quick electrical connection with the testing instrument, an upper electrical connector is provided on the top plate of the fixture, and all the metal plates are connected to the upper electrical connector via wires. This upper electrical connector can be a plug or a socket, as can the lower electrical connector described below. Alternatively, the testing instrument can be directly mounted on the top plate of the fixture, in which case all wires are connected to the corresponding testing instrument wires.
[0010] Preferably, for ease of processing, assembly and electrical connection, a lower electrical connector is provided on the upper part of the tooling base plate, and all the metal pieces are respectively connected to the lower electrical connector, which is connected to the upper electrical connector through wires.
[0011] Preferably, in order to perform resistance tests on more PTC thermistors at once, the pressure clamping device, the lower electrical connector, and the upper electrical connector are all in multiple one-to-one correspondences, and the multiple lower electrical connectors and the multiple upper electrical connectors are connected to each other by wires.
[0012] Preferably, in order to facilitate the installation of metal sheets, achieve reliable electrical connections, and reduce the number of wires, the fixture base plate is a printed circuit board. Each of the upper strip grooves has a vertical groove through hole in the center of the groove bottom. Each of the metal sheets has an integrally formed vertical metal pin on the upper outer wall of the middle part. The upper end of each metal pin passes through the corresponding groove through hole and is welded to the corresponding printed line endpoint on the fixture base plate. The printed line is connected to the corresponding lower electrical connector.
[0013] Preferably, in order to better place the tooling in the opening of the oil tank and achieve reliable positioning, the tooling top plate is provided with a downwardly protruding top plate boss. The lateral dimension of the top plate boss is equal to or greater than the lateral dimension of the tooling bottom plate, and the top plate boss is located directly above the tooling bottom plate.
[0014] Preferably, in order to achieve a more reliable clamping function, the upper surface of the clamping base plate is provided with a lower strip groove at the position corresponding to all the metal sheets.
[0015] The beneficial effects of this utility model are as follows:
[0016] This invention utilizes a pressure clamping device, comprising a clamping base plate, a clamping top plate, and metal sheets, mounted on a tooling base plate. During clamping, the entire device is first flipped over, and the leads of multiple leaded PTC thermistors are placed into the corresponding slots of the metal sheets. The clamping base plate is then rotated to press down on all the leads, and the clamping screws are installed. This allows for rapid and efficient clamping of multiple leaded PTC thermistors. The entire device can then be flipped over and placed in an oil bath for heating. The pressure clamping method between the clamping base plate and the clamping top plate prevents mechanical damage to the leads, better protecting the product's appearance. Furthermore, the strip-shaped through holes on the clamping base plate and the clamping top plate ensure that all leaded PTC thermistors are immersed in silicone oil after the clamping base plate is placed in the oil bath, achieving uniform heating. Attached Figure Description
[0017] Figure 1 This is a front view of the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors described in this utility model.
[0018] Figure 2 This is a left view of the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors described in this utility model.
[0019] Figure 3 This is a top view of the high-efficiency clamping fixture for testing the resistance of leaded PTC thermistors described in this utility model.
[0020] Figure 4This is a bottom view of the high-efficiency clamping fixture for testing the resistance of leaded PTC thermistors described in this utility model.
[0021] Figure 5 This is one of the bottom perspective views of the pressure clamping device of the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors described in this utility model before assembly, and the figure shows the leaded PTC thermistor.
[0022] Figure 6 This is the second bottom perspective view of the pressure clamping device of the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors described in this utility model before assembly, showing the leaded PTC thermistor.
[0023] Figure 7 This is a front view of the assembled pressure clamping device of the high-efficiency clamping fixture for testing the resistance of leaded PTC thermistors described in this utility model.
[0024] Figure 8 This is a bottom view of the assembled pressure clamping device of the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors described in this utility model. The figure shows the leaded PTC thermistor.
[0025] Figure 9 This is a top view of the assembled pressure clamping device of the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors described in this utility model, showing the leaded PTC thermistor. Detailed Implementation
[0026] The present invention will be further described below with reference to the accompanying drawings:
[0027] like Figures 1-9As shown, the high-efficiency clamping fixture for resistance testing of leaded PTC thermistors of this invention includes a horizontal fixture base plate 4, a horizontal fixture top plate 1, and a pressure clamping device 8. The horizontal dimension of the fixture base plate 4 is smaller than that of the fixture top plate 1. The lower ends of multiple vertical columns 3 are connected to the fixture base plate 4, and the upper ends of multiple vertical columns 3 are connected to the fixture top plate 1. The pressure clamping device 8 includes a clamping base plate 81, a clamping top plate 80, and a metal sheet 85. The horizontal clamping top plate 80 is installed below the fixture base plate 4, and the clamping base plate 85 is located below the clamping top plate 80. One end of plate 81 is rotatably connected to one end of clamping top plate 80 via a pin. The middle of clamping bottom plate 81 and clamping top plate 80 are respectively provided with vertically corresponding and vertically penetrating strip-shaped through holes 87. On the underside of clamping top plate 80, located on opposite sides of its strip-shaped through holes 87, are provided multiple upwardly recessed upper strip-shaped grooves 82. Each upper strip-shaped groove 82 contains a metal sheet 85 of a corresponding shape. The other end of clamping bottom plate 81 is connected to the other end of clamping top plate 80 via a clamping screw 86. All metal sheets 85 are led to tooling top plate 1 via wires 6. The upper strip-shaped groove 82 is preferably an arc-shaped groove with a radial arc cross-section. Therefore, the metal sheet 85 is strip-shaped with an arc-shaped radial cross-section, which allows for a tight fit with the upper strip-shaped groove 82 and facilitates the placement of the leads of the leaded PTC thermistor.
[0028] like Figures 1-9 As shown, this utility model also discloses the following more optimized specific structures:
[0029] To facilitate quick electrical connection with the testing instrument, an upper electrical connector 5 is provided on the top plate 1 of the fixture. All metal plates 85 are connected to the upper electrical connector 5 via wires 6. The upper electrical connector 5 can be a plug or a socket as needed, as can the lower electrical connector 7 described below. In addition to this structure, the testing instrument can also be directly mounted on the top plate 1 of the fixture, in which case all wires 6 are connected to the corresponding testing instrument.
[0030] To facilitate processing, assembly, and electrical connection, a lower electrical connector 7 is provided on the upper part of the tooling base plate 4. All the metal pieces 85 are connected to the lower electrical connector 7 respectively. The lower electrical connector 7 is connected to the upper electrical connector 5 through the wire 6.
[0031] In order to perform resistance tests on more PTC thermistors at once, the pressure clamping device 8, the lower electrical connector 7 and the upper electrical connector 5 are all in one-to-one correspondence, and the multiple lower electrical connectors 7 and multiple upper electrical connectors 5 are connected to each other by wires 6.
[0032] To facilitate the installation of the metal sheet 85, achieve reliable electrical connection, and reduce the number of wires, the fixture base plate 4 is a printed circuit board. Each upper strip groove 82 has a vertical groove through hole 83 in the middle of its groove bottom. Each metal sheet 85 has an integrally formed vertical metal pin 84 on the upper outer wall of its middle part. The upper end of each metal pin 84 passes through the corresponding groove through hole 83 and is soldered to the end of the corresponding printed line (not visible in the figure) on the fixture base plate 4. The printed line is connected to the corresponding lower electrical connector 7.
[0033] In order to enable this tooling to be better placed in the groove of the oil tank (not shown in the figure) and to achieve reliable positioning, a downward protruding top plate boss 2 is provided under the top plate 1 of the tooling. The lateral dimension of the top plate boss 2 is equal to or slightly larger than the lateral dimension of the bottom plate 4 of the tooling, and the top plate boss 2 is located directly above the bottom plate 4 of the tooling.
[0034] To achieve a more reliable clamping function, the upper part of the clamping base plate 81 is provided with a lower strip groove (not visible in the figure) at the position corresponding to all the metal pieces 85.
[0035] like Figures 1-9 As shown, before testing, first flip the fixture (i.e., rotate it vertically 180°), then remove the clamping screw 86, and hold the base plate 81 upwards ( Figure 5 and Figure 6 Because it is not flipped, it is facing downwards. Then, the leads of multiple leaded PTC thermistors 9 are placed in the corresponding slots of the metal plates 85, and then the base plate 81 is held downwards by hand. Figure 5 and Figure 6 Rotate the fixture (upwards, as it is not flipped) until the clamping base plate 81 and clamping top plate 80 fit tightly together, pressing the leads of the lead-type PTC thermistors 9 firmly. Then install and lock the clamping screws 86. Flip the fixture over to complete the clamping of multiple lead-type PTC thermistors 9. Then control the temperature of the silicone oil in the oil tank to reach the preset temperature and maintain it at a constant temperature. Place the entire fixture into the oil tank (not shown in the figure) from top to bottom through the opening. Use the fixture top plate 1 for support, the top plate boss 2 and the opening of the oil tank for lateral positioning, and the strip through hole 87 to immerse all lead-type PTC thermistors 9 in silicone oil. Then connect the upper electrical connector 5 to the testing instrument (not shown in the figure) and keep it for 10 to 20 minutes to allow all lead-type PTC thermistors 9 to reach the set temperature. Then the resistance value of each lead-type PTC thermistor 9 can be tested by the testing instrument.
[0036] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.
Claims
1. A high-efficiency clamping fixture for resistance testing of leaded PTC thermistors, comprising a horizontal fixture base plate and a horizontal fixture top plate, wherein the horizontal dimension of the fixture base plate is smaller than the horizontal dimension of the fixture top plate, the lower ends of a plurality of vertical columns are respectively connected to the fixture base plate, and the upper ends of the plurality of vertical columns are respectively connected to the fixture top plate, characterized in that: The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors further includes a pressure clamping device, which includes a clamping base plate, a clamping top plate, and metal sheets. The horizontally oriented clamping top plate is installed below the fixture base plate. One end of the clamping base plate, located below the clamping top plate, is rotatably connected to one end of the clamping top plate. The clamping base plate and the clamping top plate are respectively provided with vertically corresponding and vertically penetrating strip-shaped through holes. The bottom of the clamping top plate is provided with multiple upwardly recessed upper strip-shaped grooves located on opposite sides of its strip-shaped through holes. Each upper strip-shaped groove is fitted with a metal sheet of a corresponding shape. The other end of the clamping base plate is connected to the other end of the clamping top plate by a clamping screw. All the metal sheets are led to the fixture top plate by wires.
2. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors according to claim 1, characterized in that: The tooling top plate is equipped with an upper electrical connector, and all the metal pieces are connected to the upper electrical connector by wires.
3. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors according to claim 2, characterized in that: The tooling base plate is provided with a lower electrical connector, and all the metal pieces are respectively connected to the lower electrical connector. The lower electrical connector is connected to the upper electrical connector through wires.
4. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors according to claim 3, characterized in that: The pressure clamping device, the lower electrical connector, and the upper electrical connector are all in one-to-one correspondence, and the multiple lower electrical connectors and the multiple upper electrical connectors are connected to each other by wires.
5. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors according to claim 3, characterized in that: The tooling base plate is a printed circuit board. Each of the upper strip grooves has a vertical groove through hole in the middle of the groove bottom. Each metal sheet has an integrally formed vertical metal pin on the upper outer wall of the middle part. The upper end of each metal pin passes through the corresponding groove through hole and is welded to the corresponding printed line endpoint on the tooling base plate. The printed line is connected to the corresponding lower electrical connector.
6. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors according to any one of claims 1-5, characterized in that: The tooling top plate has a downward protruding top plate boss on its underside. The lateral dimension of the top plate boss is equal to or greater than the lateral dimension of the tooling bottom plate, and the top plate boss is located directly above the tooling bottom plate.
7. The high-efficiency clamping fixture for resistance testing of leaded PTC thermistors according to any one of claims 1-5, characterized in that: The clamping base plate has a lower strip groove at the position corresponding to all the metal sheets on its upper surface.