Kelvin clamp for testing axial two-stage lead device

Abstract

The utility model provides a Kelvin clamp for testing an axial two-stage lead device. The Kelvin clamp comprises an insulating bottom plate, a square mounting table is arranged in the middle of the insulating bottom plate; a through hole is formed in the side surface of the square mounting table; a lead groove is formed in the top of the conductive seat plate, a mounting hole is machined in the side wall, perpendicular to the lead groove, of the conductive seat plate, and a binding post is arranged on any side wall, parallel to the lead groove, of the conductive seat plate; two through holes are formed in the center line of the probe seat, and guide sleeves are mounted in the through holes; according to the utility model, no friction exists between the diode and the clamp in the testing process, so that the diode is prevented from being scratched; and in the clamping process, only the probe seat needs to do vertical movement, so that the control is simple.

Description

Technical Field

[0001] The utility model relates to a Kelvin fixture used for testing axial two-stage lead devices. Background Art

[0002] The Kelvin fixture is a device used to measure large currents and small resistances using the Kelvin bridge method. Its working principle is to separate the current lead and the measuring lead to prevent the current from being transferred to the resistance on the measuring lead, causing measurement errors. The Kelvin fixture is designed to eliminate the resistance of the resistor wire leads to ensure accurate measurement results, and is mainly used in high-precision measurement scenarios. In the measurement of axial two-stage lead devices, the main structure of the currently common Kelvin fixture is a metal spring with left and right poles installed on an insulating base. During work, the fixture is usually fixed on the test seat, and the device is placed on the fixture by a person to complete the test. As described above, the use of the fixture is static, and during the test process, there is friction between the device leads and the metal springs, which scratches the device leads and does not meet the requirements of automated testing. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a Kelvin fixture for testing axial two-stage lead devices.

[0004] The utility model is realized through the following technical solutions.

[0005] The utility model provides a Kelvin fixture for testing axial two-stage lead devices, comprising an insulating base plate; a square mounting platform is arranged in the middle of the insulating base plate, and a through hole is processed on the side of the square mounting platform; a conductive base plate, a lead groove is arranged on the top of the conductive base plate, a mounting hole is processed on the side wall of the conductive base plate perpendicular to the lead groove, and a terminal is arranged on any side wall parallel to the lead groove; a probe base, two through holes are processed on the center line of the probe base, and a guide sleeve is installed in the through hole;

[0006] The two conductive base plates are respectively installed on both sides of the square mounting platform, and the center lines of the mounting holes and the through holes on the insulating bottom plate are in the same straight line;

[0007] A probe is installed in the guide sleeve, the top of the probe is movably installed in the guide sleeve, a pressure head is provided at the bottom of the probe, and a spring is installed on the probe between the pressure head and the probe.

[0008] The wire guide groove is a square groove, and oval grooves are processed on both sides of the wire guide groove.

[0009] The spacing between the elliptical grooves on both sides of the lead groove is greater than the diameter of the pressure head.

[0010] The tops of both sides of the lead groove are processed with inner chamfers.

[0011] The tops of the two side surfaces of the conductive seat plate parallel to the lead groove are processed with external chamfers, and the end of the probe seat that contacts the spring is processed with a limiting groove, and the center line of the limiting groove and the lead groove are on the same plane; the width of the limiting groove is greater than the width of the top of the probe seat and less than the width of the middle of the probe seat.

[0012] The edge of the insulating bottom plate is also processed with a plurality of positioning holes and countersunk holes.

[0013] There are at least two mounting holes on the conductive base plate.

[0014] The distance between the top of the square mounting platform and the lead groove is greater than the diameter of the diode to be tested.

[0015] The utility model has the beneficial effects of: no friction between the diode and the fixture during the test process, thus preventing the diode from being scratched; and the clamping process only requires the probe seat to move vertically, which is simple to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the device of the utility model;

[0017] Figure 2 This is a front view structural diagram of the device of the utility model;

[0018] Figure 3 It is a side structural schematic diagram of the device of the utility model;

[0019] In the figure: 1-insulating base plate, 11-square mounting table, 12-positioning hole, 13-countersunk hole, 2-conductive seat plate, 21-mounting hole, 22-elliptical groove, 23-binding post, 24-product receiving groove, 25-guide sleeve, 26-external chamfer, 27-inner chamfer, 28-lead groove, 3-probe seat, 31-limiting groove, 4-probe, 41-spring, 42-pressure head, 5-diode lead. DETAILED DESCRIPTION

[0020] The technical solution of the utility model is further described below, but the scope of protection required is not limited to the description.

[0021] A Kelvin fixture for testing axial two-stage lead devices, comprising an insulating base plate 1; a square mounting platform 11 is provided in the middle of the insulating base plate 1, and a through hole is processed on the side of the square mounting platform 11; a conductive base plate 2, a lead groove 28 is provided on the top of the conductive base plate 2, a mounting hole 21 is processed on the side wall of the conductive base plate 2 perpendicular to the lead groove 28, and a terminal 23 is provided on any side wall parallel to the lead groove 28; a probe base 3, two through holes are processed on the center line of the probe base 3, and a guide sleeve 25 is installed in the through hole;

[0022] The two conductive base plates 2 are respectively mounted on both sides of the square mounting platform 11, and the center lines of the mounting holes 21 and the through holes on the insulating base plate 1 are in the same straight line;

[0023] Furthermore, a probe 4 is installed in the guide sleeve 25 , the top of the probe 4 is movably installed in the guide sleeve 25 , a pressure head 42 is provided at the bottom of the probe 4 , and a spring 41 is installed on the probe 4 between the pressure head 42 and the probe 4 .

[0024] Furthermore, the lead groove 28 is a square groove, and oval grooves 22 are processed on both sides of the lead groove 28 .

[0025] Furthermore, the distance between the elliptical grooves 22 on both sides of the lead groove 28 is greater than the diameter of the pressure head 42 .

[0026] Furthermore, inner chamfers 27 are formed on the tops of both sides of the lead groove 28 .

[0027] Furthermore, the tops of the two side surfaces of the conductive seat plate 2 parallel to the lead groove 28 are processed with external chamfers 26, and the end of the probe seat 3 in contact with the spring 41 is processed with a limiting groove 31, and the limiting groove 31 and the center line of the lead groove 28 are on the same plane; the width of the limiting groove 31 is greater than the width of the top of the probe seat 3 and less than the width of the middle of the probe seat 3.

[0028] Furthermore, a plurality of positioning holes 12 and countersunk holes 13 are processed on the edge of the insulating base plate 1 .

[0029] Furthermore, there are at least two mounting holes 21 on the conductive base plate 2 .

[0030] Furthermore, the distance between the top of the square mounting platform 11 and the lead groove 28 is greater than the diameter of the diode to be tested.

[0031] The spring on the probe is mainly used for bipolar voltage loading of axial bipolar lead devices. The probe diameter is usually determined with reference to the diameter of the device under test. To ensure effective contact with the device, the probe diameter is larger than the diameter of the device under test. According to the lead length of the device under test, a more suitable installation position is selected and installed on the probe seat;

[0032] The conductive base plate 2 is composed of two metal blocks, which are mainly used for positioning the device and two-level current loading. This structure can withstand relatively large currents. A lead groove 28 larger than the lead diameter of the device under test is opened at the top of the conductive base plate 2 according to the lead diameter of the device under test, which is used for positioning the device under test to ensure that the position of each incoming material is fixed. An elliptical groove 22 larger than the probe diameter is opened according to the probe diameter to correct and constrain the probe test point.

[0033] The base 1 is made of insulating material and has an inverted T-shaped structure. It is used to fix the device locator and is installed horizontally at the test work point when in use. The probe seat 3 is made of insulating high-voltage resistant material to ensure that the leakage current is below the pA level during high-voltage testing. The fixture can be used on axial bipolar lead device automated testing and sorting equipment. In automated testing, the test data of the test fixture is stable and reliable, meeting the requirements of large current, high voltage four-wire Kelvin testing.

[0034] In the embodiment, the fixture is used in the test process of the automated test sorting equipment. The fixture described in this patent has been applied in the axial diode automatic sorting machine used by our company. The auxiliary action structure is used to realize the up and down movement of the fixture to automatically locate the device under test and pick it up. After the test, the upper and lower parts are automatically separated to start the next round of testing. This reciprocating process realizes automated testing.

Claims

1. A Kelvin fixture for testing axial two-stage lead devices, comprising an insulating base plate (1), characterized in that: A square mounting platform (11) is provided in the middle of the insulating base plate (1), and a through hole is processed on the side of the square mounting platform (11); a conductive base plate (2), a lead groove (28) is provided on the top of the conductive base plate (2), a mounting hole (21) is processed on the side wall of the conductive base plate (2) perpendicular to the lead groove (28), and a terminal (23) is provided on any side wall parallel to the lead groove (28); a probe base (3), two through holes are processed on the center line of the probe base (3), and a guide sleeve (25) is installed in the through hole; The two conductive seat plates (2) are respectively mounted on two sides of the square mounting platform (11), and the center lines of the mounting holes (21) and the through holes on the insulating bottom plate (1) are on the same straight line; A probe (4) is installed in the guide sleeve (25), the top end of the probe (4) is movably installed in the guide sleeve (25), a pressure head (42) is provided at the bottom of the probe (4), and a spring (41) is installed on the probe (4) between the pressure head (42) and the probe (4).

2. The Kelvin fixture for testing axial two-stage lead devices according to claim 1, characterized in that: The wire guide groove (28) is a square groove, and oval grooves (22) are processed on both sides of the wire guide groove (28).

3. The Kelvin fixture for testing axial two-stage lead devices as claimed in claim 2, characterized in that: The spacing between the elliptical grooves (22) on both sides of the wire guide groove (28) is greater than the diameter of the pressure head (42).

4. The Kelvin fixture for testing axial two-stage lead devices as claimed in claim 2, characterized in that: The tops of both sides of the lead groove (28) are processed with inner chamfers (27).

5. The Kelvin fixture for testing axial two-stage lead devices according to claim 1, characterized in that: The tops of the two side surfaces of the conductive seat plate (2) parallel to the lead groove (28) are processed with external chamfers (26); the end of the probe seat (3) in contact with the spring (41) is processed with a limiting groove (31); the limiting groove (31) and the center line of the lead groove (28) are on the same plane; the width of the limiting groove (31) is greater than the width of the top of the probe seat (3) and less than the width of the middle of the probe seat (3).

6. The Kelvin fixture for testing axial two-stage lead devices according to claim 1, characterized in that: The edge of the insulating bottom plate (1) is also processed with a plurality of positioning holes (12) and countersunk holes (13).

7. The Kelvin fixture for testing axial two-stage lead devices according to claim 1, characterized in that: There are at least two mounting holes (21) on the conductive base plate (2).

8. The Kelvin fixture for testing axial two-stage lead devices according to claim 1, characterized in that: The distance between the top of the square mounting platform (11) and the lead groove (28) is greater than the diameter of the diode to be tested.

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