A measuring device for measuring the diameter and depth of microholes by using the eddy current effect

Abstract

The present invention relates to a measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect, belonging to the technical field of eddy current measurement. It includes a sliding table mechanism and a measuring mechanism; the sliding table mechanism includes a stepping motor, a ball screw and a sliding table; the output shaft of the stepping motor is connected to the input end of the ball screw; the sliding table is threadedly engaged on the ball screw to achieve position adjustment along the ball screw; the measuring mechanism includes a probe holder and an eddy current measuring probe; the eddy current measuring probe is fixedly arranged on the probe holder, and the detection part corresponds to the sliding table below. During measurement, the workpiece to be measured is fixed on the sliding table, and the sliding table driven by the stepping motor moves slowly and uniformly on the ball screw. The micro-holes on the workpiece to be measured affect the eddy current effect between the workpiece to be measured and the measuring coil on the eddy current measuring probe, resulting in a change in the inductance value of the measuring coil. By the characteristics of the change in the inductance value of the measuring coil, the measurement of the diameter and depth of the micro-holes on the workpiece to be measured is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of eddy current measurement, and particularly relates to a measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect. Background Art

[0002] With the continuous development of China's manufacturing level, the requirements for the processing quality of industrial production parts are becoming increasingly strict. Dimension measurement is the main method for evaluating processing quality, including the measurement of external dimensions and internal dimensions of parts. Among them, compared with the measurement of external dimensions, the measurement of internal dimensions has problems such as low measurement efficiency and low measurement accuracy due to measurement limitations. The measurement of the diameter and depth of micro-holes belongs to the measurement of internal dimensions. The common micro-hole measurement methods mainly include contact measurement and non-contact measurement. The invention patent CN201310352479.0 designs a measuring device for the inner hole of a bearing sleeve, and realizes the contact measurement of the inner hole of the bearing sleeve by using a detection rod; the invention patent CN201911321488.7 designs an ultra-deep hole measurement component and realizes the contact measurement of ultra-deep holes by using a coordinate measuring machine, but the contact measurement methods cannot avoid the influence of the measurement force on the measurement results. The invention patent CN201710322539.2 designs an inner hole measuring instrument, and realizes the non-contact measurement of the aperture of the inner hole by using a capacitive sensor; the invention patent CN202110285459.0 proposes a bearing inner hole measuring device and method based on a laser sensor, and realizes the non-contact measurement of the inner hole of the bearing by using a laser sensor, but these two non-contact measurement methods cannot simultaneously complete the measurement of the diameter and depth of the hole. Summary of the Invention

[0003] In order to realize the simultaneous measurement of the diameter and depth of micro-holes, the present invention proposes a measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect.

[0004] A measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect includes a sliding table mechanism and a measuring mechanism;

[0005] The sliding table mechanism includes a workbench 1, a stepping motor 2, a ball screw 3 and a sliding table 4. The stepping motor 2 is fixedly arranged on the workbench 1. The ball screw 3 is fixedly arranged on the workbench 1 through a bracket. The output shaft of the stepping motor 2 is connected to the input end of the ball screw 3. The sliding table 4 is sleeved on the ball screw 3 and is in threaded cooperation with the ball screw 3 to realize the adjustment of the position of the sliding table 4 along the ball screw 3;

[0006] The measuring mechanism includes a probe support 9 and an eddy current measuring probe 10; the probe support 9 is an L-shaped support, the end of the long side of which is fixed on the workbench 1, and the end of the short side is located above the sliding table 4; the eddy current measuring probe 10 is fixedly arranged on the short side of the probe support 9, and the detection part corresponds to the sliding table 4 below;

[0007] During measurement, the workpiece to be measured 11 is fixed on the sliding table 4 through the fixing seat 5, and the sliding table 4 driven by the stepping motor 2 moves uniformly at the working speed v on the ball screw 3, so as to realize the measurement of the diameter and depth of the micro-hole by the eddy current probe 10;

[0008] During the measurement operation, the measurement coil 6 will generate an eddy current ring 13 on the workpiece to be measured 11 under the excitation of a sinusoidal signal with a frequency of 1 MHz and an amplitude of 1 V; the eddy current ring 13 is a ring of induced current generated by an induced electromagnetic field, not a physical entity, and the eddy current ring 13 is located on the surface of the workpiece to be measured on the side with the micro-hole 12; the outer diameter of the eddy current ring 13 is d, and the outer diameter d of the eddy current ring 13 is greater than the diameter D of the micro-hole 12.

[0009] When the sliding table 4 moves uniformly at the working speed v to realize the measurement of the micro-hole by the eddy current probe 10, record the time t from the start change to the end change of the inductance value of the measurement coil 6. The relationship between the time t of the change of the inductance value of the measurement coil 6 and the diameter D of the micro-hole is: v×t = D + d, where d is the outer diameter of the eddy current ring 13.

[0010] When the sliding table 4 moves uniformly at the working speed v to realize the measurement of the micro-hole by the eddy current probe 10, record the peak inductance Lm of the measurement coil 6. The relationship between the peak inductance Lm of the measurement coil 6 and the diameter D of the micro-hole is: Lm = kD 2 + L0, where L0 is the initial inductance of the measurement coil 6, k is the slope of the linear relationship between the peak inductance Lm of the measurement coil 6 and the square of the diameter of the micro-hole to be measured, and the relationship between k and the depth h of the micro-hole is: h = m1k 2 + m2k + m3, where m1, m2, and m3 are measurement coefficients.

[0011] The further technical solution is as follows:

[0012] The measuring range of the diameter of the micro-hole measured by the measuring device is 1 mm - 5 mm, the measuring resolution of the diameter of the micro-hole is 0.01 mm, and the measuring error of the diameter of the micro-hole is less than 0.02 mm; the measuring range of the depth of the micro-hole is 0 - 0.5 mm, the measuring resolution of the depth of the micro-hole is 0.01 mm, and the measuring error of the depth of the micro-hole is less than 0.02 mm.

[0013] Guide rods are respectively arranged on the brackets on both sides of the ball screw 3 of the sliding table mechanism, and the guide rods on both sides are parallel to the ball screw 3; the sliding table 4 is sleeved on the ball screw 3 and the guide rods on both sides at the same time, and the sliding table 4 and the guide rods are in clearance fit.

[0014] An installation hole is provided on the short side of the probe support 9 of the measuring mechanism. A V-shaped groove is provided on one side hole wall of the installation hole, and the V-shaped angle of the V-shaped groove is 90°. A set screw 7 is provided on the probe support 9 opposite to the V-shaped groove. The end of the set screw 7 is connected with a pressing block 8, and the working surface of the pressing block 8 is an arc surface. The eddy current measuring probe 10 is fixedly installed in the installation hole on the short side of the probe support 9, and the eddy current measuring probe 10 is clamped through the cooperation of the working surface of the pressing block 8 and the V-shaped groove.

[0015] The eddy current measuring probe 10 is an LHP-J type probe. The outer diameter of the measuring coil 6 at the measuring end of the eddy current measuring probe 10 facing the slide 4 is 7.5 mm, and the inner diameter is 1.5 mm. The measuring coil 6 is a cylindrical coil wound with 0.05 mm enameled wire for 48 turns in a single layer.

[0016] The distance x between the measuring coil 6 on the eddy current measuring probe 10 and the vertical direction of the workpiece to be measured is 0.05 - 0.15 mm.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are reflected in the following aspects:

[0018] 1. The measuring device of the present invention utilizes the eddy current effect between the measuring coil and the workpiece to be measured to measure the diameter and depth of the micro-holes on the workpiece. During the measurement process, there is no contact between the measuring coil and the workpiece to be measured, and the measurement of the micro-holes belongs to non-contact measurement, which can effectively avoid the influence of the measuring force on the measurement result in contact measurement.

[0019] 2. The measuring device of the present invention generates an eddy current ring on the surface of the workpiece to be measured where the micro-holes are located through the eddy current effect between the measuring coil and the workpiece to be measured. During the measurement process, the change in the relative position between the eddy current ring and the micro-holes will affect the inductance value of the measuring coil. The diameter and depth of the micro-holes are measured by the change characteristics of the inductance value of the measuring coil, which is a new type of micro-hole measurement method.

[0020] 3. The measuring device of the present invention reflects the size of the micro-hole diameter through the change time t of the inductance value of the measuring coil. The measured value of the micro-hole diameter can be determined by the moving speed v of the workpiece to be measured, the change time t of the inductance value of the measuring coil, and the outer diameter d of the eddy current ring. Among them, v = 10 mm / s and d = 17 mm. The relative movement speed between the eddy current ring and the micro-holes can be reduced by reducing the moving speed v of the workpiece to be measured to increase the change time t of the inductance value of the measuring coil, thereby improving the resolution of the micro-hole diameter measurement. The measurement range of the micro-hole diameter that the measuring device of the present invention can achieve is 1 mm - 5 mm, the diameter measurement resolution can be as low as 0.01 mm, and the diameter measurement error is less than 0.02 mm.

[0021] 4. The measuring device of the present invention measures the micro-hole depth by measuring the peak value of the coil inductance. During the micro-hole measurement process, the peak value of the coil inductance is affected by both the micro-hole diameter and depth simultaneously. The present invention decouples the coupled influence of the micro-hole diameter and depth on the peak value of the coil inductance by processing the linear relationship between the peak value of the coil inductance and the square of the micro-hole diameter, and obtains the measured value of the micro-hole depth by using the slope of the linear relationship between the peak value of the coil inductance and the square of the micro-hole diameter. The measuring range of the micro-hole depth that can be achieved by the measuring device of the present invention is 0 - 0.5 mm, the measuring resolution of the micro-hole depth is 0.01 mm, and the error of the depth measurement is less than 0.02 mm.

[0022] 5. When the measuring device of the present invention measures the micro-hole, the sliding table drives the workpiece to be measured to move from left to right relative to the eddy current measuring probe. The entire measurement process only needs to be carried out once without reciprocating motion. Compared with other non-contact measurement principles, after the measurement process of the micro-hole by the measuring device of the present invention is completed, the measurement results of both the micro-hole diameter and depth can be obtained simultaneously. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the device of the present invention.

[0024] Figure 2 is a schematic diagram of the fixed structure of the V-groove eddy current measuring probe on the probe support.

[0025] Figure 3 is a schematic diagram of the measuring coil on the eddy current probe.

[0026] Figure 4 is a top view of the sliding table mechanism during operation and a schematic diagram of the positional relationship between the eddy current ring and the micro-hole on the workpiece to be measured.

[0027] Figure 5 is a schematic diagram of the device of the present invention during operation.

[0028] Figure 6 is a schematic diagram of the change in the relative positional relationship between the eddy current ring and the micro-hole during the measurement process.

[0029] Figure 7 is a schematic diagram of the change process of the inductance value of the measuring coil during the measurement process.

[0030] Figure 8 is a schematic diagram of the relationship between the peak value of the coil inductance Lm and the micro-hole diameter D.

[0031] Figure 9 is a schematic diagram of the relationship between the peak value of the coil inductance Lm and the square of the micro-hole diameter D 2 of.

[0032] Figures 1-4Serial numbers: workbench 1, stepper motor 2, ball screw 3, slide 4, fixed seat 5, measuring coil 6, set screw 7, pressing block 8, probe holder 9, eddy current measuring probe 10, workpiece to be measured 11, micro-hole 12, eddy current ring 13. Detailed implementation manners

[0033] The present invention will be further described below with reference to the accompanying drawings through embodiments.

[0034] See Figure 1 , a measuring device for measuring the diameter and depth of a micro-hole by using the eddy current effect includes a slide mechanism and a measuring mechanism.

[0035] See Figure 1 , the slide mechanism includes a workbench 1, a stepper motor 2, a ball screw 3 and a slide 4. The stepper motor 2 is fixedly installed on the workbench 1. The ball screw 3 is fixedly installed on the workbench 1 through a bracket, and the output shaft of the stepper motor 2 is connected to the input end of the ball screw 3; guide rods are respectively installed on the brackets on both sides of the ball screw 3, and the guide rods on both sides are parallel to the ball screw 3. The slide 4 is sleeved on the ball screw 3 and the guide rods on both sides at the same time, and there is a clearance fit between the slide 4 and the guide rods; the slide 4 is in threaded fit with the ball screw 3 to realize the adjustment of the position of the slide 4 along the ball screw 3.

[0036] See Figure 1 , the measuring mechanism includes a probe holder 9 and an eddy current measuring probe 10. The probe holder 9 is an L-shaped bracket, and the end of the long side is fixedly installed on the workbench 1, and the end of the short side is located above the slide 4. See Figure 2 , an installation hole is opened on the short side of the probe holder 9, a V-shaped groove is opened on one side wall of the installation hole, and the V-shaped angle of the V-shaped groove is 90°. A set screw 7 is installed on the probe holder 9 opposite to the V-shaped groove, and the end of the set screw 7 is connected to a pressing block 8, and the working surface of the pressing block 8 is an arc surface.

[0037] The model of the eddy current measuring probe 10 is LHP-J type probe. The eddy current measuring probe 10 is fixedly installed in the installation hole on the short side of the probe holder 9, and the eddy current measuring probe 10 is clamped by the working surface of the pressing block 8 and the V-shaped groove. The measuring coil 6 of the eddy current measuring probe 10 corresponds to the slide 4 below.

[0038] See Figure 3 , the outer diameter of the measuring coil 6 at the measuring end of the eddy current measuring probe 10 facing the slide 4 is 7.5 mm, the inner diameter is 1.5 mm, the measuring coil 6 is a single-layer cylindrical coil wound with 0.05 mm enameled wire for 48 turns, the excitation signal of the measuring coil 6 is a sine signal with a frequency of 1 MHz and an amplitude of 1 V, and the distance x between the measuring coil 6 and the workpiece to be measured on the slide 4 in the vertical direction is 0.05 - 0.15 mm.

[0039] The material of the component under test 11 is aluminum alloy 7075, and it is a cuboid component. The component under test 11 has a micro-hole 12 with a diameter of D and a depth of h. Refer to Figure 5 , the component under test 11 and the fixed seat 5 are fixed on the sliding table 4 by an interference fit. Refer to Figure 4 , during the measurement operation, when the measurement coil 6 is excited by a sinusoidal signal with a frequency of 1 MHz and an amplitude of 1 V, the eddy current effect between the measurement coil 6 and the component under test 11 will generate an eddy current ring 13 on the component under test 11. The eddy current ring 13 is an induced current ring, not a physical entity, and the eddy current ring 13 is located on the surface of the side of the component under test with the micro-hole 12. The outer diameter of the eddy current ring 13 is d, and the outer diameter d of the eddy current ring 13 is greater than the diameter D of the micro-hole.

[0040] During operation, the excitation signal of the measurement coil 6 is a sinusoidal signal with a frequency of 1 MHz and an amplitude of 1 V, and the distance x between the measurement coil 6 and the component under test on the sliding table 4 in the vertical direction is 0.05 - 0.15 mm.

[0041] The measurement range of the micro-hole diameter by the measurement device of the present invention is 1 mm - 5 mm, the measurement resolution of the micro-hole diameter is 0.01 mm, and the measurement error of the micro-hole diameter is less than 0.02 mm; the measurement range of the micro-hole depth is 0 - 0.5 mm, the measurement resolution of the micro-hole depth is 0.01 mm, and the measurement error of the micro-hole depth is less than 0.02 mm.

[0042] The working principle of the measurement device of the present invention for measurement is described in detail as follows:

[0043] Refer to Figure 6 and Figure 7 , the measurement process of the micro-hole by the measurement device of the present invention is described in detail: Refer to Figure 6 , during the measurement process in which the sliding table 4 drives the component under test 11 to move from left to right at a speed v, the relative positional relationship between the eddy current ring 13 on the component under test 11 and the micro-hole 12 can be divided into nine moments t1 - t9. The inductance values of the measurement coil 6 corresponding to the nine moments t1 - t9 are referred to Figure 7 .

[0044] The entire measurement process is divided into two processes: t1 - t6 and t6 - t9; when the measurement process is in the t1 - t6 process, at the moment t1, the eddy current ring 13 and the micro-hole 12 are not in contact, and the inductance value of the measurement coil 6 remains unchanged. At this time, the inductance value of the measurement coil 6 is L0, which refers to the inductance value at the moment t1 in Figure 7 ;

[0045] At the moment t2, the eddy current ring 13 and the micro-hole 12 just come into contact, and the inductance value of the measurement coil 6 begins to increase. Refer to the inductance value of the measurement coil 6 at the moment t2 in Figure 7 ;

[0046] When the measurement process transitions from time t3 to time t4, the micro-hole 12 enters the eddy current ring 13. Since the eddy current density on the eddy current ring is high, the inductance value of the measurement coil 6 keeps increasing and reaches its peak value at time t4. This peak value is denoted as the peak inductance Lm of the measurement coil. Refer to Figure 7 the inductance value of the measurement coil 6 at time t4 in

[0047] When the measurement process transitions from time t5 to time t6, the micro-hole 12 moves from the eddy current ring 13 to the middle of the eddy current ring 13. During this process, the eddy current density gradually decreases along the movement path of the micro-hole 12, and the inductance value of the measurement coil 6 also decreases accordingly. Refer to the change in the inductance value of the measurement coil 6 during the t4 - t6 process in 7.

[0048] When the measurement process is in the t6 - t9 process, due to the symmetry of the relative movement between the micro-hole 12 and the eddy current ring 13, the micro-hole 12 starts to move back from the middle of the eddy current ring 13 to the eddy current ring 13, resulting in an increase in the inductance value of the measurement coil 6 from t6 to t8. And the inductance value of the measurement coil at time t8 is equal to that at time t4, both being Lm. Refer to the change in the inductance value of the measurement coil 6 during the t6 - t8 process in 7;

[0049] At time t9, the micro-hole 12 leaves the eddy current ring 13, and the inductance value of the measurement coil 6 returns to L0 and stops changing. Refer to Figure 7 In the whole measurement process, the influence of the micro-hole 12 on the inductance value of the measurement coil 6 is distributed from time t2 to time t9, and the time during which the micro-hole 12 causes the change in the inductance value of the measurement coil 6 is t.

[0050] The relationship between the time t during which the micro-hole 12 causes the change in the inductance value of the measurement coil 6 and the micro-hole diameter D during the measurement process is v×t = D + d, where d is the outer diameter of the eddy current ring, d = 17 mm, and v is the movement speed of the test piece 6, v = 10 mm / s. Therefore, by obtaining the time t during which the micro-hole 12 causes the change in the inductance value of the measurement coil 6, the size of the micro-hole diameter D can be obtained, realizing the measurement of the micro-hole diameter by this measurement device.

[0051] Refer to Figure 8 the relationship between the peak inductance Lm of the measurement coil and the micro-hole diameter D. When the micro-hole depth h is constant, as the micro-hole diameter D increases, the peak inductance Lm of the measurement coil also increases. The peak inductance Lm of the measurement coil and the micro-hole diameter D have a quadratic function relationship. When the micro-hole diameter D is constant, as the micro-hole depth h increases, the peak inductance Lm of the measurement coil also increases.

[0052] Refer to Figure 9 the relationship between the peak inductance Lm of the measurement coil and the square of the micro-hole diameter D 2 When the micro-hole depth h is constant, the peak inductance Lm of the measurement coil and the square of the micro-hole diameter D 2It shows a linear relationship, and the expression of the linear relationship is: Lm = kD 2 + L0, where L0 is the initial inductance value of the measuring coil, D is the diameter of the micro-hole, and k is the peak inductance Lm of the measuring coil and the square D of the micro-hole diameter 2 The slope of the linear relationship; when the micro-hole diameter D is constant, as the micro-hole depth h increases, the peak inductance Lm of the measuring coil and the square D of the micro-hole diameter 2 The slope of the linear relationship increases accordingly. The relationship between the micro-hole depth h and k is: h = m 1 k 2 + m 2 k + m 3 , m 1 , m 2 . m 3 is the measurement coefficient, which is obtained through data fitting after obtaining the measurement data of all micro-holes by performing the above measurement process on micro-holes with diameters of 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm; and depths of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm respectively. Therefore, after the measurement of the micro-hole diameter D is completed, substituting Lm and the micro-hole diameter D into Lm = kD 2 + L0 can obtain the slope k of the linear relationship between Lm and the square D of the micro-hole diameter 2 Through the formula h = m 1 k 2 + m 2 k + m 3 the size of the micro-hole depth h can be obtained, realizing the measurement of the micro-hole depth by this measuring device.

[0053] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect, characterized in that: it includes a sliding table mechanism and a measuring mechanism; The sliding table mechanism includes a workbench (1), a stepping motor (2), a ball screw (3) and a sliding table (4). The stepping motor (2) is fixedly arranged on the workbench (1). The ball screw (3) is fixedly arranged on the workbench (1) through a bracket. The output shaft of the stepping motor (2) is connected to the input end of the ball screw (3). The sliding table (4) is sleeved on the ball screw (3) and is in threaded cooperation with the ball screw (3) to realize the adjustment of the position of the sliding table (4) along the ball screw (3); The measuring mechanism includes a probe holder (9) and an eddy current measuring probe (10). The probe holder (9) is an L-shaped bracket, and the end of the long side is fixed on the workbench (1), and the end of the short side is located above the sliding table (4). The eddy current measuring probe (10) is fixedly arranged on the short side of the probe holder (9), and the detection part corresponds to the sliding table (4) below; When the sliding table (4) moves at a working speed v uniformly to realize the measurement of the micro-hole by the eddy current measuring probe (10), record the time t when the inductance value of the measuring coil (6) changes from the start to the end. The relationship between the time t of the change of the inductance value of the measuring coil (6) and the diameter D of the micro-hole is: v×t = D + d, where d is the outer diameter of the eddy current ring (13); When the sliding table (4) moves at a constant working speed v to realize the measurement of the micro-hole by the eddy current measurement probe (10), the peak inductance Lm of the measurement coil (6) is recorded. The relationship between the peak inductance Lm of the measurement coil (6) and the micro-hole diameter D is: Lm = kD 2 + L0, where L0 is the initial inductance of the measurement coil (6), and k is the slope of the linear relationship between the peak inductance Lm of the measurement coil (6) and the square of the diameter of the micro-hole to be measured. The relationship between k and the micro-hole depth h is: h = m1k 2 + m2k + m3, where m1, m2, and m3 are measurement coefficients; During measurement, the workpiece to be measured (11) is fixed on the sliding table (4) through a fixing seat (5). The sliding table (4) driven by the stepping motor (2) moves uniformly on the ball screw (3) at a working speed v to realize the measurement of the diameter and depth of the micro-hole by the eddy current measuring probe (10); During the measurement work, when the measuring coil (6) is excited by a sinusoidal signal with a frequency of 1 MHz and an amplitude of 1 V, an eddy current ring (13) will be generated on the workpiece to be measured (11). The eddy current ring (13) is an induction current ring generated by the induced electromagnetic field, not a solid, and the eddy current ring (13) is located on the surface of the side of the workpiece to be measured with the micro-hole (12). The outer diameter of the eddy current ring (13) is d, and the outer diameter d of the eddy current ring (13) is larger than the diameter D of the micro-hole (12).

2. The measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect according to claim 1, characterized in that: The measuring range of the measuring device for the diameter of the micro-hole is 1 mm - 5 mm, the measuring resolution of the diameter of the micro-hole is 0.01 mm, and the measuring error of the diameter of the micro-hole is less than 0.02 mm; the measuring range of the depth of the micro-hole is 0 - 0.5 mm, the measuring resolution of the depth of the micro-hole is 0.01 mm, and the measuring error of the depth of the micro-hole is less than 0.02 mm.

3. The measuring device for measuring the diameter and depth of micro-holes by using the eddy current effect according to claim 1, characterized in that: Guide rods are respectively arranged on the brackets on both sides of the ball screw (3) of the sliding table mechanism, and the guide rods on both sides are parallel to the ball screw (3). The sliding table (4) is simultaneously sleeved on the ball screw (3) and the guide rods on both sides, and the sliding table (4) and the guide rods are in clearance fit.

4. A measuring device for measuring the diameter and depth of a micro-hole by using the eddy current effect according to claim 1, characterized in that: an installation hole is provided on the short side of the probe holder (9) in the measuring mechanism, a V-shaped groove is provided on one side hole wall of the installation hole, and the V-shaped angle of the V-shaped groove is 90°; a set screw (7) is provided on the probe holder (9) opposite to the V-shaped groove, the end of the set screw (7) is connected with a pressing block (8), and the working surface of the pressing block (8) is an arc surface; the eddy current measuring probe (10) is fixedly installed in the installation hole on the short side of the probe holder (9), and the eddy current measuring probe (10) is clamped through the cooperation of the working surface of the pressing block (8) and the V-shaped groove.

5. A measuring device for measuring the diameter and depth of a micro-hole by using the eddy current effect according to claim 1, characterized in that: the eddy current measuring probe (10) is an LHP-J type probe, the outer diameter of the measuring coil (6) at the measuring end of the eddy current measuring probe (10) facing the sliding table (4) is 7.5 mm, the inner diameter is 1.5 mm, and the measuring coil (6) is a single-layer cylindrical coil wound with 0.05 mm enameled wire for 48 turns.

6. A measuring device for measuring the diameter and depth of a micro-hole by using the eddy current effect according to claim 1, characterized in that: the distance x in the vertical direction between the measuring coil (6) on the eddy current measuring probe (10) and the workpiece to be measured (11) is 0.05 - 0.15 mm.

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