A drift-free eddy current sensor for microscale measurements

Abstract

This invention discloses an anti-drift eddy current sensor for microscale measurement, belonging to the field of high-precision measuring instrument technology. The instrument includes a glass substrate, which is divided into symmetrical elastic clamping arms and a fixed clamping base by an arc-shaped dividing groove. Each of the two has a clamping part of equal radius arc, forming a three-point positioning clamping station. An arc-shaped hinge end is provided at the end of the dividing groove, and parameters such as the substrate thickness, clamping angle, and the size and position of the hinge end are precisely quantified and defined. This invention eliminates electromagnetic interference and ensures structural deformation resistance using a glass substrate. It achieves precise cooperation with the sensor through three-point positioning. By optimizing structural parameters to balance substrate stiffness and fracture risk, the sensor is subjected to uniform force and accurate concentric positioning. At the same time, the instrument has no additional driving / locking components, avoiding error accumulation. It is easy to operate, highly stable, and suitable for industrial applications of precision testing.

Description

Technical Field

[0001] This invention relates to the field of high-precision measuring instrument technology, specifically to an anti-drift eddy current sensor for microscale measurement. Background Technology

[0002] In the production and testing of precision sensors, a specialized clamping device is required for precise positioning and fixation of the sensor. This is then combined with inductive measuring equipment to complete dimensional measurements. The positioning accuracy, material properties, and force uniformity of the clamping device directly affect the accuracy of the measurement results. In existing technologies, the fixture substrates used for sensor clamping and measurement are mostly made of metal or ordinary plastic. Metal substrates are prone to electromagnetic interference, interfering with inductive measurement signals and leading to decreased measurement accuracy. Ordinary plastic substrates lack rigidity and are prone to plastic deformation over long-term use, causing clamping and positioning deviations. Furthermore, they have poor wear resistance and a short service life.

[0003] Meanwhile, the clamping logic and clamping methods of traditional clamping devices mostly involve driving and locking components. In the field of precision measurement, the cooperation of different components is not only structurally complex and costly, but more importantly, it is easy to accumulate errors, making it difficult to guarantee detection accuracy. The accumulated errors are more obvious under the influence of temperature and humidity, sensor drift is not easy to control, and it is also difficult to achieve precise matching with the sensor diameter. Summary of the Invention

[0004] The purpose of this invention is to provide an anti-drift eddy current sensor for microscale measurements, so as to solve the problems mentioned in the background art.

[0005] An anti-drift eddy current sensor for microscale measurement includes a substrate, which is mounted on an external detection frame via a connecting part. The substrate is made of glass, utilizing the properties of glass—no electromagnetic interference, high rigidity, low coefficient of expansion, low creep, and low stress relaxation—to eliminate electromagnetic interference in the measurement signal at its source. Simultaneously, it ensures the deformation resistance of the clamping structure, suppresses long-term clamping position drift, and ensures the relative position stability of the sensor. The substrate is divided by a slot into a pair of symmetrically arranged clamping arms and a clamping base. The clamping arms are elastic clamping arms capable of controllable elastic deformation, while the clamping base is a fixed base providing stable support for the overall clamping. The clamping arms have a first clamping part, and the clamping base has a second clamping part. The two first clamping parts and the second clamping part together constitute a clamping station, achieving precise positioning of the target sensor based on the three-point positioning principle, and ensuring a precise fit between the clamping station and the diameter of the target sensor.

[0006] As a further aspect of the present invention, the side of the dividing groove furthest from the clamping station is close to the sidewall of the substrate, and the end of the dividing groove furthest from the clamping station is a hinge end. This hinge end serves as the core area for the elastic deformation of the clamping arm, making the deformation of the clamping arm more concentrated and controllable, thus improving the accuracy of deformation adjustment. The thickness of the substrate corresponding to the clamping station is not less than two-thirds of the length of the target sensor, thereby ensuring the rigidity of the substrate at the clamping station and preventing deformation of the station area due to force during clamping, ensuring the stability of the clamping positioning accuracy.

[0007] As a further aspect of the present invention, the clamping angle between the second clamping part and the adjacent first clamping part is between 110 and 130 degrees. This angle is adapted to the structure of the elastic clamping arm and the fixed clamping seat, so that the target sensor is subjected to uniform force within the clamping station, and the force directions applied by each clamping part to the sensor intersect at one point, effectively preventing uncertain deformation of the sensor housing and avoiding positioning deviation caused by housing deformation. Both the first clamping part and the second clamping part are arc structures with equal radii, ensuring the fit with the arc-shaped outer contour sensor, increasing the force-bearing area of ​​the clamping contact, and avoiding stress concentration at the contact point between the clamping part and the sensor; and the curvature of the second clamping part is greater than that of a single first clamping part, using the second clamping part as the main force-bearing point and positioning reference, which facilitates the control of the clamping centroid of the clamping station and further improves the anti-displacement effect of the sensor. In the non-clamping state, the centers of the two clamping parts are located below the center of the clamping part. In the clamping state, the three centers coincide, thereby achieving concentric positioning of the target sensor and improving clamping positioning accuracy. At the same time, the clamping force value that the clamping structure can provide to the target sensor in the clamping state can be determined by the preset center deviation, ensuring the controllability of the clamping force.

[0008] As a further aspect of the present invention, the dividing groove is arc-shaped and convex towards the sidewall of the substrate. On the one hand, this reduces the overall weight of the clamping arm, and reduces the required opening force when the clamping arm is opened to place the target sensor, improving operational convenience. On the other hand, it avoids stress concentration in the substrate during deformation, preventing cracking damage due to stress concentration. The hinge end is arc-shaped, and the closest distance between the hinge end and the sidewall of the substrate is between the radius and diameter of the hinge end itself. This ensures that the hinge end has sufficient deformation space while preventing insufficient strength of the substrate sidewall due to the hinge end being too close, thus ensuring the overall structural stability of the substrate. The radius of the hinge end is less than one-fifth of the radius of the dividing groove, causing the deformation of the clamping arm to be concentrated at the hinge end, further improving the controllability of deformation. Moreover, the arc curvature of the hinge end can match and fit the arc of the dividing groove, preventing breakage at the junction of the hinge end and the dividing groove when the clamping arm is opened. This achieves an optimal balance between substrate stiffness and fracture risk while ensuring the elastic deformation capability of the clamping arm.

[0009] As a further aspect of the present invention, the instrument relies on the elastic deformation of the glass substrate itself to clamp and reset the sensor, eliminating the need for additional driving and locking components. This simplifies the overall structure, reduces manufacturing costs, avoids error accumulation caused by the cooperation of multiple components, and is less affected by temperature and humidity environmental factors, effectively ensuring the stability of detection accuracy.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] To eliminate electromagnetic interference and ensure long-term stability of the clamping structure, the substrate is made of glass, which eliminates the electromagnetic interference generated by traditional metal substrates on the inductive measurement signal from the root, greatly improving measurement accuracy. At the same time, glass has the characteristics of high rigidity, low coefficient of expansion, low creep and low stress relaxation. It will not undergo plastic deformation after long-term use, which can suppress long-term drift of the clamping position, ensure the relative position stability of the target sensor, and effectively extend the service life of the instrument.

[0012] Achieving precise clamping bypasses the need for multiple parts to work together, ensuring accurate positioning without deviation. The clamping station is designed based on the three-point positioning principle, and the three-circle center coincidence design in the clamping state enables concentric and precise positioning of the sensor. Furthermore, the clamping angle of 110 to 130 degrees ensures uniform force on the sensor, and the force directions of each clamping part intersect at a single point, preventing uncertain deformation of the sensor housing and completely avoiding measurement errors caused by clamping deviation. Attached Figure Description

[0013] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0014] Figure 2 shows the present invention. Figure 1 A top-down view from a specific perspective;

[0015] Figure 3 is a schematic diagram of a partial structure of the clamping station of the present invention;

[0016] Figure 4 is a schematic diagram of the dimensions and structure of the dividing groove and the hinge end (clamping arm connection) of the present invention;

[0017] Figure 5 is a schematic diagram showing the matching of the thickness of the clamping station substrate and the length of the target sensor in this invention.

[0018] Figure 6 is a schematic diagram of the center position of the clamping part of the present invention;

[0019] Figure 7 is a schematic diagram of the force applied to the clamping part of the present invention and its interaction with the sensor.

[0020] The attached figures are labeled as follows:

[0021] 1 - Base, 1-1 - Clamping arm, 1-1-1 - Clamping part one, 1-2 - Clamping seat, 1-2-1 - Clamping part two, 1-3 - Dividing groove, 1-3-1 - Hinge end, 1-4 - Connecting part, 2 - Target sensor, 3 - Target plate; r1 - Radius of the arc of the clamping part, r2 - Radius of the dividing groove, r3 - Radius of the hinge end, a1 - Radius of clamping part one, a2 - Radius of clamping part two, L - Distance between the hinge end and the side wall, L1 - Thickness of the base body at the clamping station, L2 - Target sensor length, O1 - center of the circle corresponding to clamping part one (left side), O2 - center of the circle corresponding to clamping part one (right side), O - center of the circle corresponding to clamping part two, f1 - force direction corresponding to clamping part one (left side), f2 - force direction corresponding to clamping part one (right side), f3 - force direction corresponding to clamping part two. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figures 1-7 This invention provides a technical solution: an anti-drift eddy current sensor for microscale measurement, comprising a substrate 1, wherein a connecting part 1-4 is provided at the end of the substrate 1, and the substrate 1 is fixedly connected to an external detection frame through the connecting part 1-4; the substrate 1 is made of glass, which eliminates electromagnetic interference at the source, and at the same time, the low creep and low stress relaxation of the glass material suppress long-term drift, thereby ensuring the relative position stability of the target sensor 2; the substrate 1 is provided with a dividing groove, which divides the substrate 1 into a pair of symmetrically arranged clamping arms 1-1 and a clamping seat 1-2; the clamping arms 1-1 are elastic clamping arms that can generate controllable elastic deformation; the clamping seat 1-2 is a fixed base that provides stable support for clamping.

[0024] The clamping arm 1-1 has a clamping part 1-1-1 on the side facing the clamping seat 1-2, and the clamping seat 1-2 has a clamping part 1-2-1 on the side facing the clamping arm 1-1. The two clamping parts 1-1-1 and the one clamping part 1-2-1 are arranged together to form a clamping station based on the three-point positioning principle. The clamping station is precisely matched with the diameter of the target sensor 2, and the physical properties of glass are used to prevent the sensor from drifting, so as to achieve accurate positioning of the target sensor 2.

[0025] The dividing groove, on the side away from the clamping station, approaches the sidewall of the base 1, and the end of the dividing groove away from the clamping station is the hinge end 1-3-1. Utilizing the elastic deformation of the glass body, the clamping arm 1-1 can rotate slightly, ensuring stable clamping. Simultaneously, the hinge end 1-3-1's proximity to the sidewall ensures both the elastic deformation capability of the clamping arm 1-1 and prevents breakage at the connection due to excessive stress. The thickness of the base 1 corresponding to the clamping station is not less than 2 / 3 of the length of the target sensor 2 to ensure the rigidity of the base 1 at the clamping station and prevent deformation of the station area due to clamping force.

[0026] The clamping angle between clamping part 2 1-2-1 and the adjacent clamping part 1 1-1-1 is 110°-130°. This angle design is compatible with the combined structure of the elastic clamping arm and the fixed base, ensuring that the target sensor 2 is evenly distributed in the clamping position. See [reference needed]. Figure 7 At the same time, the directions of force (f1, f2, and f3 refer to the directions of force applied by the three clamping parts to the target sensor 2) intersect at a point; this can effectively prevent the housing of the target sensor 2 from undergoing uncertain deformation, thereby ensuring that the target sensor 2 avoids displacement or damage.

[0027] Both clamping part 1-1-1 and clamping part 2-2-1 are arc structures, and the arc radii of clamping part 1-1-1 and clamping part 2-2-1 are equal. The arc curvature of clamping part 2-2-1 is greater than that of a single clamping part 1-1-1 (i.e., a2 is greater than a1 as shown in 3). Clamping part 2-2-1 serves as the main force-bearing point and positioning reference, located on clamping seat 1-2, which facilitates control of the clamping centroid of the clamping station and improves the anti-deviation effect. The arc structure is not a critical constraint, but is mainly used to optimize the stress distribution of the substrate 1, increase the force-bearing area of ​​the target sensor 2 shell, and prevent stress concentration at the contact points between clamping part 1-1-1 / clamping part 2-2-1 and the target sensor 2. It also adapts to the miniaturized design of the instrument. In the non-clamping state, the two clamping parts 1-1-1... The corresponding centers are all located below the corresponding center of clamping part 1-2-1. In the clamping state, the centers of the two clamping parts 1-1-1 coincide with the center of clamping part 1-2-1 (i.e., Figure 6 (The centers O1, O2, and O of the clamping parts 1 and 2 coincide), achieving concentric positioning of the target sensor 2 and further improving clamping accuracy; see [link to relevant documentation]. Figure 6 By using the preset center deviation, the value of the clamping force that clamping part one / clamping part two can provide to the target sensor 2 under the clamping state is determined (where the magnitude of the clamping force is mainly determined by the deformation L3 of clamping part one under the clamping state), thereby ensuring that the clamping force is controllable.

[0028] The dividing grooves 1-3 are all arc-shaped structures, and each of them protrudes towards the sidewall of the base 1. This reduces the weight of the clamping arm, resulting in a smaller opening force when the clamping arm 1-1 is opened to place the target sensor 2. Secondly, it avoids stress concentration when the base 1 deforms. Furthermore, it works in conjunction with the arc-shaped structure of the hinge end 1-3-1 to optimize overall stress. As shown in Figure 3, the curvature of the hinge end 1-3-1 matches the dividing grooves 1-3, preventing breakage at the junction of the hinge end 1-3-1 and the dividing grooves 1-3 when the clamping arm 1-1 is opened. The hinge end 1-3-1 is arc-shaped, and the closest distance between the hinge end 1-3-1 and the sidewall of the base 1 is between the radius and diameter of the arc of the hinge end 1-3-1. This ensures sufficient deformation space for the hinge end 1-3-1 while preventing insufficient strength of the sidewall of the base 1. The radius of the arc is less than 1 / 5 of the radius of the arc of the dividing groove, so that the deformation of the clamping arm 1-1 is concentrated at the hinge end 1-3-1, which improves the controllability of deformation and further balances stiffness and fracture risk.

[0029] During clamping: First, use a tool to spread the clamping arms 1-1 to both sides, so that after the clamping arms 1-1 are opened, the center height of clamping part one 1-1-1 is higher than the height of clamping part two 1-2-1; thus forming an installation space slightly larger than the diameter of the target sensor 2; place the target sensor 2 into the installation space and adjust the orientation of the target sensor 2; then release the clamping arms 1-1, which will hold the target sensor 2 in the clamping position, forming... Figure 1 and Figure 6 The installation status on the right is used to detect the target board 3.

[0030] Taking quartz glass as an example:

[0031] Where: r1=1.5mm; r2=12.8mm; r3=4mm; L=2.2mm; L1=12mm; L2=9mm; a1=76.17°; a2=137.91°

[0032] After 1000 hours of continuous monitoring under constant temperature (20℃) conditions, the sensor attitude deviation is ≤0.1μm.

[0033] After a 10~2000Hz sweep frequency vibration, the zero-point drift is ≤0.01% FS.

[0034] After cycling from -40℃ to 85℃, the sensitivity drift is ≤0.05% FS.

Claims

1. A drift-proof eddy current sensor for micro-scale measurements, comprising a base body (1) which is arranged on an externally attached detection frame by a connection (1-4), characterized in that: The substrate (1) is made of glass. The substrate (1) is divided into a pair of symmetrically arranged clamping arms (1-1) and clamping seats (1-2) by a dividing groove. The clamping arms (1-1) are provided with a clamping part one (1-1-1), and the clamping seats (1-2) are provided with a clamping part two (1-2-1). The two clamping parts one (1-1-1) and one clamping part two (1-2-1) together constitute a clamping station with three-point positioning. The clamping arm (1-1) is an elastic clamping arm, and the clamping base (1-2) is a fixed base; The side of the dividing groove away from the clamping station is close to the side wall of the base (1), and the end of the dividing groove away from the clamping station is a hinged end (1-3-1).

2. The anti-drift eddy current sensor for microscale measurement according to claim 1, characterized in that: The thickness of the substrate (1) corresponding to the clamping station is not less than 2 / 3 of the length of the target sensor (2).

3. The anti-drift eddy current sensor for microscale measurement according to claim 1, characterized in that: The clamping angle between the second clamping part (1-2-1) and the adjacent first clamping part (1-1-1) is between 110° and 130°.

4. The anti-drift eddy current sensor for microscale measurement according to claim 1, characterized in that: Both clamping part one (1-1-1) and clamping part two (1-2-1) are circular arcs with equal radii; and the arc of clamping part two (1-2-1) is greater than the arc of clamping part one (1-1-1).

5. The anti-drift eddy current sensor for microscale measurement according to claim 4, characterized in that: In the non-clamping state, the centers of the two clamping parts (1-1-1) are located below the center of the clamping part (1-2-1). In the clamping state, the three centers coincide.

6. The anti-drift eddy current sensor for microscale measurement according to claim 1, characterized in that: The dividing grooves (1-3) are all arc-shaped and protrude towards the side wall of the substrate (1).

7. The anti-drift eddy current sensor for microscale measurement according to claim 2, characterized in that: The hinge end (1-3-1) is arc-shaped; and the closest distance between the hinge end (1-3-1) and the side wall of the base (1) is between the radius and diameter of the hinge end (1-3-1).

8. The anti-drift eddy current sensor for microscale measurement according to claim 7, characterized in that: The radius of the hinge end (1-3-1) is less than 1 / 5 of the radius of the dividing groove.

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