A high-precision depth dimension measuring device and method

Abstract

The present invention relates to a high-precision depth dimension measuring device and method. The measuring device comprises a housing (1), a nut (2), a liquid (5), a large piston (6), a large spring (8), a small spring (12), a small piston (13) and a reading area (14). The measuring method derives from the incompressibility of the liquid that the volume reduction of the step-type through hole (4) is equal to the volume increase of the blind hole (11), i.e., V1=V2. It can be deduced that the displacement of the piston is inversely proportional to the square of the radius of the piston cross section. The depth dimension change is amplified by the radius difference between the measuring end and the reading end, which is convenient for reading. The measuring accuracy can reach μ level. Compared with a general depth gauge or caliper, the device has higher accuracy. Compared with a general lever gauge, the part structure has stronger adaptability, lower cost, and more convenient use and maintenance. It can greatly save production time for mass production.

Description

Technical Field

[0001] The invention relates to the field of dimension measuring instruments, in particular to a high-precision depth dimension measuring device and method. Background Art

[0002] As an important part of the engine combustion chamber, the dimensional accuracy of the nozzle parts directly affects the assembly effect and test performance. Its high quality and stable and reliable performance are of great significance to aircraft engines, and its working performance directly affects the power, fuel economy and reliability of the engine. The existing direct depth dimension measurement tools are generally calipers, depth gauges or depth micrometers. Due to the size limitation of the measuring tool, the depth dimension of the small hole feature cannot be measured or is inaccurate, making it difficult to control the consistency of the depth dimension of the processed parts. It depends largely on the machine tool program guarantee, which prolongs the part selection process and increases the difficulty of debugging in the later test and debugging stages. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high-precision depth dimension measuring device and method. According to the incompressibility of the liquid, the reduction in the volume of the liquid in the step-type through hole is equal to the increase in the volume of the liquid in the blind hole, that is, V1=V2. It can be inferred that the displacement of the piston is inversely proportional to the cross-sectional area of ​​the piston. The depth dimension change is amplified by the ratio of the cross-sectional area of ​​the measuring end and the reading end, which is easy to read.

[0004] The purpose of the present invention is achieved through the following technical solutions: a high-precision depth dimension measuring device and method, the measuring device includes a shell, a nut, a large piston, a large piston probe and a large spring, a threaded hole is opened in the nut, the threaded hole passes through the upper end surface of the nut, the inner ring of the nut is connected to the outer ring of the bottom of the shell through a thread, the lower end of the shell has a stepped through hole processed to the inside of the shell, the stepped through hole is filled with liquid and a large piston, the large piston is arranged at the lower end of the stepped through hole, the large piston diameter There are several spring grooves on the outer end surface. The large spring is evenly arranged between the large aperture part of the stepped through hole and the spring groove. A through hole is opened at the lower end of the nut. The large piston probe extends to the outside of the shell through the through hole. A blind hole is also opened inside the shell. The lower end of the blind hole passes through the stepped through hole, and the upper end of the blind hole is terminated inside the shell. A small spring and a small piston are arranged in the blind hole. The small spring is arranged on the upper part of the small piston. A reading area is arranged next to the blind hole. A sealing ring is arranged on the large piston on the upper part of the large spring. The small piston used for indication is reset by the elastic force of the small spring. The large piston used for measurement is pre-tightened by the elastic force of the large spring and the end face of the nut. Appropriate pre-tightening is used to eliminate the transmission error caused by the gap when the large piston is measured. The shell and the large piston are sealed by a sealing ring to prevent liquid leakage.

[0005] A high-precision depth dimension measuring device and method, the measuring method comprises the following steps:

[0006] Use a standard gauge block to measure and calibrate the length H0 of the large piston probe, and record the indication in the reading area;

[0007] During measurement, the large piston probe contacts the step surface where the measured depth dimension ends, and the measuring device is moved to make the starting step surface of the measured depth dimension fit with the step surface of the nut, and the piston displacement change △H2 in the reading area is recorded;

[0008] The measured depth dimension H=H0-△H2 / γ, where γ is the ratio of the cross-sectional area of ​​the small inner diameter portion of the step-type via hole to the cross-sectional area of ​​the blind hole.

[0009] Preferably, the reading area is a groove processed on the shell, and a sealed perspective device is provided between the reading area and the blind hole.

[0010] Preferably, the number of the spring slot is at least one.

[0011] Preferably, the number of the large springs is consistent with the number of the spring slots.

[0012] Preferably, the through hole diameter is smaller than the inner diameter of the bottom of the large piston.

[0013] Preferably, the optimal shape of the stepped via hole and the blind hole is cylindrical.

[0014] Preferably, the radius of the small inner diameter part of the stepped via is R1, the radius of the blind hole is R2, the preferred value of R2:R1 is 10, the change in liquid level in the stepped via is △H1, the displacement of the piston in the blind hole is △H2, the reduction in liquid volume in the stepped via is equal to the increase in liquid volume in the blind hole, that is, R1²△H1=R2²△H2, and γ=△H2 / △H1=R1² / R2², and the preferred value of γ is 1 / 100.

[0015] The present invention has the following advantages:

[0016] According to the incompressibility of liquid, the present invention designs a high-precision depth dimension measurement device and method. The volume reduction of the liquid in the stepped through hole is equal to the volume increase of the liquid in the blind hole, that is, V1=V2. It can be deduced that the displacement of the piston is inversely proportional to the square of the radius of the piston cross section. The depth dimension change is amplified by the radius difference between the measuring end and the reading end, which is easy to read and the measurement accuracy can reach μ level. Compared with general depth gauges or calipers, the device has higher accuracy. Compared with general lever meters, the part structure has stronger adaptability, lower cost, and more convenient use and maintenance. It can greatly save production time for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 is a flow chart of the measuring method of the present invention;

[0019] In the figure: 1-housing, 2-nut, 3-threaded hole, 4-step-type through hole, 5-liquid, 6-large piston, 7-spring groove, 8-large spring, 9-through hole, 10-large piston probe, 11-blind hole, 12-small spring, 13-small piston, 14-reading area, 15-sealing ring. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0021] like Figure 1 As shown, a high-precision depth dimension measuring device and method, the measuring device includes a shell 1, a nut 2, a large piston 6, a large piston probe 10 and a large spring 8, a threaded hole 3 is opened in the nut 2, the threaded hole 3 passes through the upper end surface of the nut 2, the inner ring of the nut 2 is connected to the outer ring of the bottom of the shell 1 through a thread, the lower end of the shell 1 has a stepped through hole 4 processed to the inside of the shell, the stepped through hole 4 is filled with liquid 5 and a large piston 6, the large piston 6 is arranged at the lower end of the stepped through hole 4, the radial outer end surface of the large piston 6 is opened with a plurality of spring grooves 7, the number of the spring grooves 7 is at least 1, the large spring 8 is evenly arranged between the large aperture part of the stepped through hole 4 and the spring groove 7, the The number of large springs 8 is consistent with the number of spring grooves 7. A sealing ring 15 is provided on the large piston 6 on the upper part of the large spring 8. A through hole 9 is opened at the lower end of the nut 2. The large piston probe 10 extends to the outside of the shell 1 through the through hole. The aperture of the through hole 9 is smaller than the inner diameter of the bottom of the large piston 6. A blind hole 11 is also opened inside the shell 1. The lower end of the blind hole 11 passes through the stepped conductive hole 4, and the upper end of the blind hole 11 is terminated inside the shell 1. A small spring 12 and a small piston 13 are arranged in the blind hole 11. The small spring 12 is arranged on the upper part of the small piston 13. A reading area 14 is arranged next to the blind hole 11. The reading area 14 is a groove processed on the shell 1, and a sealed perspective device is arranged between the reading area 14 and the blind hole 11.

[0022] like Figure 2 As shown, the working process of the present invention is as follows:

[0023] Use a standard gauge block to measure and calibrate the length H0 of the large piston probe 10, and record the initial value of the reading area 14;

[0024] During measurement, the large piston probe 10 contacts the step surface where the measured depth dimension ends, and the measuring device is moved so that the starting step surface of the measured depth dimension fits the step surface of the nut 2, and the piston displacement change △H2 in the reading area 14 is recorded;

[0025] The measured depth dimension H=H0-△H2 / γ.

[0026] The cross-sectional area of ​​the small inner diameter part of the stepped conducting hole 4 is A1, the cross-sectional area of ​​the blind hole 11 is A2, the liquid level change of the stepped conducting hole 4 is △H1, and the displacement of the piston in the blind hole 11 is △H2, wherein A1, A2 and △H2 are all calculable values, the reduction in liquid volume of the stepped conducting hole 4 is equal to the increase in liquid volume of the blind hole 11, that is, A1△H1=A2△H2, and γ=△H2 / △H1=A1 / A2.

[0027] When the stepped via hole 4 and the blind hole 11 are cylindrical, the radius of the small inner diameter part of the stepped via hole 4 is R1, the radius of the blind hole 11 is R2, the preferred value of R2:R1 is 10, the liquid level change in the stepped via hole 4 is △H1, the displacement of the piston in the blind hole 11 is △H2, the reduction in the liquid volume of the stepped via hole 4 is equal to the increase in the liquid volume of the blind hole 11, that is, R1²△H1=R2²△H2, the γ=△H2 / △H1=R1² / R2², and the preferred value of γ is 1 / 100.

Claims

1. A high-precision depth dimension measuring device, characterized in that: The invention comprises a housing (1), a nut (2), a large piston (6), a large piston probe (10) and a large spring (8), wherein a threaded hole (3) is formed in the nut (2), the inner ring of the nut (2) is connected to the outer ring of the bottom of the housing (1) by a thread, the lower end of the housing (1) has a stepped through hole (4) machined into the interior of the housing, the stepped through hole (4) is filled with a liquid (5) and a large piston (6), the large piston (6) is arranged at the lower end of the stepped through hole (4), the radial outer end surface of the large piston (6) is formed with a plurality of spring grooves (7), and the large spring (8) is evenly arranged in the stepped through hole (4). A through hole (9) is formed at the lower end of the nut (2) between the large aperture portion and the spring groove (7), and the large piston probe (10) extends through the through hole to the outside of the housing (1). A blind hole (11) is also formed inside the housing (1), and the lower end of the blind hole (11) passes through the stepped conductive hole (4), and the upper end of the blind hole (11) is terminated inside the housing (1). A small spring (12) and a small piston (13) are arranged in the blind hole (11), and the small spring (12) is arranged on the upper part of the small piston (13). A reading area (14) is arranged on the housing (1), and the reading area (14) is located on one side of the blind hole (11); A sealing ring (15) is provided on the large piston (6) on the upper part of the large spring (8), the reading area (14) is a groove machined on the housing (1), and a sealed perspective device is provided between the reading area (14) and the blind hole (11).

2. A high-precision depth dimension measuring device according to claim 1, characterized in that: The number of the spring groove (7) is at least one.

3. A high-precision depth dimension measuring device according to claim 2, characterized in that: The number of the large springs (8) is consistent with the number of the spring slots (7).

4. A high-precision depth dimension measuring device according to claim 1, characterized in that: The diameter of the through hole (9) is smaller than the inner diameter of the bottom of the large piston (6).

5. A high-precision depth dimension measurement method, implemented based on a high-precision depth dimension measurement device according to any one of claims 1 to 4, characterized in that: The steps include: Use a standard gauge block to measure and calibrate the length H0 of the large piston probe (10), and record the indication in the reading area (14); During measurement, the large piston probe (10) contacts the step surface where the depth dimension to be measured ends, and the measuring device is moved so that the starting step surface of the depth dimension to be measured fits the step surface of the nut (2), and the piston displacement change △H2 in the reading area (14) is recorded; The measured depth dimension H=H0-△H2 / γ, where γ is the ratio of the cross-sectional area of ​​the small inner diameter portion of the step-type through hole (4) to the cross-sectional area of ​​the blind hole (11).

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