A planar small curvature measuring instrument and method of use thereof

Abstract

A kind of plane small curvature measuring instrument and its using method belong to the technical field of ultra-precision measuring instrument.The torsion spring gauge is inserted in the middle of cross bridge, the outer side is sleeved with slider two and slider one, slider two and slider one are symmetrically arranged on the two sides of torsion spring gauge, slider two is contacted with contact three and contact two, and slider one is contacted with contact one.The method is as follows: three contacts are placed on the standard surface to calibrate the reference surface;the present application is placed at any angle, the torsion spring gauge probe is contacted with the measured plane area, the torsion spring reading is read, the plane curvature is calculated;the above step is repeated after changing the angle of measuring instrument multiple times;contact deformation compensation calculation is carried out to realize accurate measurement.The present application detects the small curvature of the measured surface by using torsion spring gauge, can realize in-situ measurement, can directly measure in the working site such as grinding machine, avoids positioning reference error caused by offline detection, is closer to actual processing condition, and small size measuring instrument can improve measuring speed.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of plane small curvature measuring instrument and its use method, belong to ultra-precision measuring instrument technical field. BACKGROUND

[0002] In addition to the traditional grinding and polishing, the processing method of ultra-precision machining manufacturing technology is derived from emerging processing methods such as plasma processing, water jet polishing and magnetorheological polishing, and the demand in the field of national defense technology makes the material exploration of ultra-precision machining possible. The requirements for processing structure are more diversified and complex, and the precision requirement can reach nanometer level, so in the field of ultra-precision machining manufacturing technology, ultra-precision machining technology and detection technology are equally important.

[0003] Convenient and accurate measurement technology can fully and accurately measure and characterize the processed surface, reflect the topography and geometric characteristics of the processed surface, and is the key to promoting the perfection of ultra-precision machining manufacturing process.

[0004] Among them, the widely used ultra-precision measuring instrument such as white light interferometer has large measurement range, high efficiency, convenient use and high precision, but the instrument has high cost and cannot be measured in place. The measured workpiece needs to be moved, and the offline detection will introduce positioning reference error, which has limitations in the range of use environment, and as an optical measurement method, it will be limited by diffraction, reflection, dispersion and other optical principles. SUMMARY

[0005] To solve the problems in the background art, the present application provides a kind of plane small curvature measuring instrument and its use method.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: a kind of plane small curvature measuring instrument, including cross bridge, sliding block two, torsion spring table and sliding block one;The middle part of the cross bridge is inserted with the torsion spring table, and the outer side of the cross bridge is slidably sleeved with the sliding block two and the sliding block one, the sliding block two and the sliding block one are symmetrically arranged on both sides of the torsion spring table, the lower surface of the sliding block two is provided with contact three and contact two, the lower surface of the sliding block one is provided with contact one, and the contact head of the contact one, the contact three and the contact two is located in the same plane.

[0007] The use method of the plane small curvature measuring instrument of the present application, the method comprises the following steps:

[0008] S1: the contact one, the contact three and the contact two of the present application are placed on the standard surface to calibrate the reference surface;

[0009] S2: select any angle of the curved surface to place the present application, read the torsion spring table as x after the measuring head of the torsion spring table contacts the measured curved surface area, and calculate the plane curvature of the angle surface.

[0010] S3: change the angle of the measuring instrument, repeat S2;

[0011] S4: repeat S3 multiple times, and fit to obtain the plane curvature;

[0012] S5: perform Hertz contact deformation compensation calculation to realize accurate measurement.

[0013] Compared with the prior art, the beneficial effects of the present application are:

[0014] The present application has the advantages of simple structure, low cost, simple maintenance, use of the existing high-precision torsion spring table to detect the small curvature of the measured surface, precision up to 1 / 3 of the graduation value, and the ability to realize in-situ measurement, direct measurement on the working site such as a grinding machine, avoidance of positioning reference error caused by offline detection, closer to the actual processing situation, and small size of the measuring instrument to improve the measurement speed. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural schematic diagram of the present application;

[0016] Figure 2 is a structural schematic diagram of the present application when calibrated on a standard surface;

[0017] Figure 3 is an effect schematic diagram of the present application when measured on a measured plane;

[0018] Figure 4 is an effect schematic diagram of the present application when measured on a measured plane to generate contact deformation;

[0019] Figure 5 is a structural schematic diagram of local contact deformation of the contact point one and the measured surface. DETAILED DESCRIPTION

[0020] The technical solutions in the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] A small curvature measuring instrument for a plane includes a cross bridge 1, a slider two 2, a torsion spring table 3, and a slider one 4.

[0022] The middle part of the cross bridge 1 is inserted with the torsion spring table 3,

[0023] Specifically,

[0024] The horizontal bridge 1 is a columnar structure, a through hole is formed in the upper end of the middle part of the outer wall of the horizontal bridge 1, the torsion spring watch 3 is installed in the through hole formed in the middle part of the horizontal bridge 1, and the lower end of the torsion spring watch 3 is fixed on the horizontal bridge 1 by screwing.

[0025] The outer side of the horizontal bridge 1 is sleeved with the sliding block two 2 and the sliding block one 4, the sliding block two 2 and the sliding block one 4 are symmetrically arranged on the two sides of the torsion spring watch 3,

[0026] Specifically,

[0027] The sliding block one 4 is sleeved on the horizontal bridge 1 and located at the left side of the torsion spring watch 3, a threaded hole one is formed in one side of the outer wall of the sliding block one 4, and the sliding block one 4 is screwed on the horizontal bridge 1 by the threaded hole one through a bolt one;

[0028] The sliding block two 2 is sleeved on the horizontal bridge 1 and located at the right side of the torsion spring watch 3, a threaded hole two is formed in one side of the outer wall of the sliding block two 2, and the sliding block two 2 is screwed on the horizontal bridge 1 by the threaded hole two through a bolt two.

[0029] The lower surface of the sliding block two 2 is provided with a contact three 5 and a contact two 6, the lower surface of the sliding block one 4 is provided with a contact one 8, and the contact heads of the contact one 8, the contact three 5 and the contact two 6 are located in the same plane.

[0030] A measuring plane is determined by the contact one 8, the contact two 6 and the contact three 5 on the sliding block one 4 and the sliding block two 2, and the position of the sliding block one 4 and the sliding block two 2 on the horizontal bridge 1 can be flexibly changed according to different measuring environments and measuring requirements.

[0031] The torsion spring watch 3 is a measuring instrument capable of converting the axial linear displacement of the measuring head 7 into the torsional displacement of the pointer, and the linear displacement of the straight line motion is proportional to the angular displacement of the pointer.

[0032] The measuring head 7 of the torsion spring watch 3 produces axial movement on the measured surface, is conducted to the three-legged stand through the amount lever supported by the circular elastic sheet and the square elastic sheet in the torsion spring watch 3, the rotation of the three-legged stand produces linear torsion on the torsion spring wire to drive the linear rotation of the pointer, and the angular displacement of the pointer is displayed on the scale disc. The measured surface is calculated by orthogonally placing the measuring instrument.

[0033] The torsion spring watch 3 has high precision and can reach micron level, and the torsion spring watch 3 is zeroed on the plane determined by the contact one 8, the contact two 6 and the contact three 5 on the standard surface 9.

[0034] The use method of the plane small curvature measuring instrument includes the following steps:

[0035] S1: The contact one 8, the contact three 5 and the contact two 6 of the present application are placed on the standard surface 9 to calibrate the reference surface, and a plane is determined by the three contact balls.

[0036] S2: The present application is placed at any angle of the curved surface, the reading of the torsion spring gauge 3 is x after the probe 7 of the torsion spring gauge 3 contacts the region of the curved surface to be measured, and the plane curvature of the angle surface is calculated;

[0037] S201: Definition: the distance between the center of the probe 7 and the center of the contact point one 8 is a;

[0038] S202: The angle surface to be measured is determined according to the intersection of the line connecting the contact point two 6 and the contact point three 5 and the plane determined by the contact point one 8 and the probe 7, and the distance between the center of the angle surface and the probe 7 is defined as the radius of curvature p;

[0039] S203: The radius of curvature p is calculated from the geometric condition

[0040] S204: The plane curvature is obtained

[0041] S3: Change the angle of the measuring instrument, and repeat S2;

[0042] S4: Repeat S3 multiple times, and fit to obtain the plane curvature;

[0043] S5: Considering that the measured material has an elastic modulus, the self-weight of the present application causes the three contact point balls to contact the measured surface, which causes Hertz contact, and then causes the deformation of the measured surface, so it is necessary to perform Hertz contact deformation compensation calculation to realize accurate measurement.

[0044] S501: Definition: the local elastic deformation caused by the Hertz contact between the contact point one 8 and the measured surface is d1, the local elastic deformation caused by the Hertz contact between the contact point two 6 and the measured surface is d2, and the local elastic deformation caused by the Hertz contact between the contact point three 5 and the measured surface is d3;

[0045] S502: The local elastic deformation d1 caused by the Hertz contact between the contact point one 8 and the measured surface is calculated according to the Palmgren formula:

[0046]

[0047] Wherein:

[0048] F is the self-weight of the present application;

[0049] l is the effective length when the contact point one 8 contacts the measured surface;

[0050] υ1 is the Poisson's ratio of the contact point one 8;

[0051] υ2 is the Poisson's ratio of the measured surface;

[0052] E1 is the elastic modulus of the contact one 8;

[0053] E2 is the elastic modulus of the measured surface;

[0054] S503: Since the contact two 6 and the contact three 5 are both made of the same material as the contact one 8, δ1 = δ2 = δ3;

[0055] S504: Through the relationship between the link error and the system comprehensive error The comprehensive contact deformation is calculated

[0056] S505: Displacement compensation is performed on the torsion spring table reading to obtain the final measurement result.

[0057] S50501: The curvature when there is no Hertz contact deformation is obtained according to S204

[0058]

[0059] S50502: Combined with the comprehensive contact deformation δ, the compensated curvature radius is calculated

[0060]

[0061] S50403: The final curvature is obtained

[0062] When the measurement result precision has higher requirements, an inductance micrometer with a measurement range of 1mm and a precision better than 100nm can be used, which has the same shape as a common small instrument and is suitable for installation on the existing cross bridge. The principle is that the displacement of the measuring rod drives the armature on the measuring rod to move, so that the mutual inductance coefficient of the coil changes, the output voltage signal changes correspondingly, and the PC end is displayed through the A / D conversion module.

[0063] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0064] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature or implementation described herein. The specification can include implicit combinations of explicitly mentioned features and / or implicit combinations of implicitly mentioned features. Such combinations are also expressly included within the scope of the specification and an embodiment.

Claims

1. A method for using a planar small curvature measuring instrument, the method is based on the completion of the measuring instrument, the measuring instrument comprising a cross bridge (1), a slider two (2), a torsion spring meter (3) and a slider one (4); the middle part of the cross bridge (1) is inserted with the torsion spring meter (3), the outer side of the cross bridge (1) is slidably sleeved with the slider two (2) and the slider one (4), the slider two (2) and the slider one (4) are symmetrically arranged on both sides of the torsion spring meter (3), the lower surface of the slider two (2) is provided with a contact three (5) and a contact two (6), the lower surface of the slider one (4) is provided with a contact one (8), the contact heads of the contact one (8), the contact three (5) and the contact two (6) are located in the same plane; characterized in that: The method comprises the following steps: S1: placing the contact one (8), the contact three (5) and the contact two (6) of the measuring instrument on the standard surface (9) for reference surface calibration; S2: placing the measuring instrument at any angle of the curved surface, reading the indication of the torsion spring gauge (3) as x after the measuring head (7) of the torsion spring gauge (3) contacts the curved surface region to be measured, and calculating the plane curvature of the angle surface; S201: defining that the distance between the center of the measuring head (7) and the center of the contact one (8) is a; S202: determining the angle surface to be measured according to the contact point of the contact one (8) and the measured surface, the contact point of the measuring head (7) and the measured surface, and the intersection of the line connecting the contact two (6) and the contact three (5) and the plane determined by the contact one (8) and the measuring head (7), and defining that the distance between the center of the angle surface and the measuring head (7) is the radius of curvature p; S203: Calculate the radius of curvature ; S204: Obtain planar curvature ; S3: changing the angle of the measuring instrument and repeating S2; S4: repeatedly performing S3 for multiple times to fit the plane curvature; S5: performing Hertz contact deformation compensation calculation to realize accurate measurement; S501: Definition: The local elastic deformation caused by the Hertz contact between the first contact point (8) and the measured surface is , the local elastic deformation caused by the Hertz contact between the second contact point (6) and the measured surface is , and the local elastic deformation caused by the Hertz contact between the third contact point (5) and the measured surface is ; S502: Calculate the local elastic deformation due to Hertzian contact between the first contact (8) and the surface under test according to the Palmgren formula : Wherein: F is the weight of the measuring instrument; l is the effective length when the contact one (8) contacts the measured surface; The Poisson's ratio of contact point one (8); Poisson's ratio of the surface being measured; The elastic modulus of contact point 1 (8); E is the modulus of elasticity of the surface being measured; S503: Since the contact two (6) and the contact three (5) are both made of the same material as the contact one (8), therefore ; S504: Relationship between link error and system integrated error Calculated integrated contact deformation ; S505: displacement compensation is performed on the reading of the torsion spring gauge to obtain the final measurement result; The displacement compensation of S505 comprises the following steps: S50501: The curvature at the time of non-Hertzian contact deformation obtained from S204 is ; S50502: combined with the comprehensive contact deformation , the radius of curvature after compensation is calculated ; S50403: Obtain final curvature .

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