Method for measuring precision orifice chamfer parameters

Abstract

The present invention discloses a method for measuring the parameters of the chamfer of a precision orifice, aiming to provide a chamfer measuring device with a simple structure and high measuring efficiency. The present invention is implemented by the following technical scheme: a positioning cylindrical plug gauge that can slide into the chamfered shaft hole is prepared, extending horizontally along the shaft end of the positioning cylindrical plug gauge, and the fixed end can be rotatably connected to the connecting rod in the vertical direction of the positioning cylindrical plug gauge, as well as a dial indicator and a standard round plug gauge for alignment vertically fixed on the free end of the connecting rod, the dial indicator actuating pivot needle is downward, and slides vertically along the upper end face of the standard round plug gauge through the mounting hole of the table frame, and the dial indicator actuating pivot needle is adjusted to "0", which is defined as the starting point of the sinking of the positioning cylindrical plug gauge measuring mandrel; the positioning cylindrical plug gauge slides into the end hole of the chamfered cone surface to be measured, forming a right triangle along the axis of the measured hole and the orifice chamfer and the orifice end face, and the chamfer opening dimension chain of the measured orifice is calculated and measured, and the chamfer opening dimension chain parameters are obtained.

Description

Technical Field

[0001] The invention relates to a measuring fixture for detecting chamfers, in particular to a precise internal hole chamfer measuring fixture which can quickly and accurately measure the actual size of the chamfer for products with high hole chamfer requirements. Background Art

[0002] Chamfering is the most common processing content in mechanical processing. Chamfering can be completed by turning, boring, grinding, milling, drilling and other processes. It is usually completed after the part processing is completed and before heat treatment. Most of the ordinary chamfering will be arranged during the finishing process. If burrs will affect the quality of subsequent processing, some chamfering will be completed during the rough processing; and some important functional chamfering will also be arranged in the grinding process after heat treatment. The main functions of chamfering are: removing sharp corners and burrs, beautifying the appearance, installing guides, and facilitating assembly. This type of chamfer is generally less than 45°, mostly 20°-30° chamfers. Chamfering can prevent bumps and protect the working surface. Chamfering between processes can reduce stress concentration, such as: chamfering the orifice of the component part that bears high pressure, chamfering the orifice of the bolt connection; reducing heat treatment deformation: in order to prevent deformation and cracking caused by stress concentration after quenching, the parts must be chamfered before heat treatment; functional surface: for example, the chamfering of the lock pin hole of the lock pin type synchronizer sleeve in the automobile gearbox. The chamfering process of the hole has different requirements due to its different functions and roles. The chamfering process is often considered as an auxiliary process in process design and is ignored by process designers. This cognitive deviation has led to a long-term stagnation in the research of the chamfering process. Among the high-end products of aerospace and military industries, some precision mechanical parts have high quality requirements for chamfering, especially the chamfering quality of the shaft hole of the gear. The processing of the hole not only requires deburring, but also has high precision requirements for angles and edge widths. It even requires that the chamfering reference end face of the part must be the same as the processed or very flat, and there must be no burrs or flash between the chamfering reference end face of the part and the chamfering bevel. The requirements for dimensional accuracy, shape accuracy and position accuracy are very high. When the chamfering angle is small, a small change in the chamfering angle will cause a large change in the chamfering height size, which cannot be met by general internal hole chamfering cutters. It has always been a problem. There is a large error between the conventional machining chamfering size and the chamfering size marked in the engineering drawing, which cannot fully meet the design requirements or use requirements. With the development of production and science and technology, people have put forward higher and higher requirements for the surface quality of engineering, and the surface measurement and evaluation methods are also advancing with the times and developing continuously. In order to ensure the quality and service life of parts, some precision internal orifices with marked chamfers often appear. More and more products have made extremely strict requirements on the size difference of the chamfers at both ends of the orifices, and the chamfering and deburring of precision difficult chamfered parts. For example: aviation, military, automotive industry oil, gas, electric valves, engine cylinders, cylinders, spherical through holes, inner wall holes, bearing mounting holes are difficult to chamfer, and the orifice chamfering accuracy requirements are extremely high. The difference in the size of the chamfers at both ends must be controlled within 0.05. The internal chamfer measurement, external chamfer measurement, cross hole chamfer, end orifice chamfer, flange hole front and back chamfer, and orifice chamfer depth requirements are high, and it is not easy to clamp. Once the chamfer size is qualified, whether the various forms of chamfered workpieces are accurately and directly measured will directly affect the overall performance and service life of the product.If the same part has holes processed on different planes and these are intersecting holes, cross holes are formed. Cross holes exist in many workpieces, such as valve bodies, hydraulic pumps, filters, cylinder heads, etc. During the processing of these cross holes, burrs are easily formed at the intersection of the two holes, and these burrs exist inside the parts, making it difficult to remove the burrs. Traditional tools cannot complete the chamfering of double-sided, inner and outer hole walls of cylinders, various valve body holes, especially small hole walls, burr repair, and chamfer measurement. There is a chamfer at the end to form a circle with the inner hole. The drawing requires controlling the distance from this circle to the bottom surface, that is, to check the depth H from the circumference to the plane to control the depth of the chamfer. However, it is quite difficult to use an absolute measurement method, so a comparative measurement method is configured to indirectly obtain the H value of a special inspection tool. Common measurement methods for descending to chamfers include: visual inspection, general measuring instruments, special measuring tools, special inspection tools, etc. At present, the basic detection method is to use a projector to detect the chamfer diameter, which is also a relatively accurate method; but this method requires large investment, has low efficiency, and cannot be inspected on site; other methods are basically visual inspection and rough measurement with a caliper. Since the caliper measurement cannot be centered, the error is very large.

[0003] At present, the measurement methods of surface quality, especially surface roughness, mostly use diamond stylus for contact measurement. The inevitable wear of the stylus will affect the measurement results. For soft metal precision surfaces, information-containing surfaces, and some surfaces that are not allowed to be scratched, the stylus method cannot be used for measurement, and non-contact measurement methods must be used. Non-contact measurement methods will not cause scratches and deformations, but are greatly affected by the optical properties of the material, the installation of the workpiece, the degree of inclination, and environmental factors, and their use is also subject to certain restrictions. Although this measurement method has reliable results, low requirements for environmental conditions, and low measurement costs. However, the disadvantage of this method is that the sharp stylus used may scratch the workpiece. The tool should be flexible during use to ensure sufficient pressure during cutting, but if the processing time is too long and the material is different, it may cause the chamfer size to exceed the requirement. If the force is too large, the blade will not be able to extend into the small hole; if the pressure is too small, it cannot withstand the cutting force during chamfering and cannot complete the chamfering task. If the chamfering is done manually with a scraper or file, the aperture is small, and the chamfering operation with high precision requirements for the inner hole is difficult. Not only is the chamfering quality difficult to guarantee, but the production efficiency is also low, and the chamfering process often becomes a bottleneck affecting production. Since the design drawings often only indicate the final size of the parts or the final coating thickness, in the actual part processing process, it is necessary to calculate the intermediate size (size before electroplating) according to the actual process. In the past, we relied on experience to give the process size, and then ground it after electroplating. The final product size did not check the coating thickness, resulting in inconsistent quality and many problems. With the improvement of product quality control and the strengthening of product inspection, it was found that many products with different diameters have different coating tolerance ranges, and the coating thickness of the products does not meet the design requirements of the drawings. Usually, the chamfering of manufactured workpieces is guaranteed by rotating tools. In actual production, the chamfering angle size may cause errors due to tool setting and feed. The size of the processed workpiece is different and may not meet the requirements of the drawing. However, the size after processing cannot be inspected at all. The micrometer cannot be inspected, and the vernier caliper cannot be measured accurately. Since the caliper measurement cannot be centered, the error is very large. Replacement of dial gauge plug Because the dial gauge plug is round, the plug of the unchamfered workpiece is pointed, the highest point of the zero dial gauge circle plug may be misaligned with the top of the workpiece, causing errors. Since the generatrix of the cone is not perpendicular to the end face, the measurement of the axial dimension of the chamfer intersection line of the hole, the perpendicularity between the inner hole axis and the upper end face, and the large end aperture is much more difficult than the straight hole measurement. The ordinary measurement method is completely inaccurate, not to mention the dimensional accuracy required on the drawing. The commonly used conical hole measurement methods (four-ball method, plug block method and flip method, etc.) are relatively cumbersome, and the inspection of chamfer dimensions has always been a problem in the manufacturing industry.

[0004] At present, various measuring instruments, such as three-coordinate measuring instruments, imagers, through-and-stop plug gauges, etc., can accurately measure whether the chamfer size is qualified. However, these measuring methods cannot efficiently or accurately measure the actual value of the chamfer size. Although the three-coordinate measuring equipment can accurately measure the actual value of the chamfer size, in actual production, if each chamfer is measured using three-coordinate measuring instruments, it will occupy a large amount of three-coordinate resources and delay the inspection time of other products. At the same time, if the chamfer size difference is detected to be unqualified, the resetting performance of the re-processing is poor, and the re-alignment processing is required, which delays a lot of production time and may even cause inaccurate alignment, resulting in scrapped parts and increased production costs. The imager can also detect the actual value of the chamfer size of the hole, but when measuring, the burrs at the chamfer of the hole have a greater impact on the measurement value, resulting in inaccurate measurement results. If the burrs at the chamfer are removed before measurement, the chamfer tip will be too smooth, affecting people's visual judgment, requiring high technical requirements for measurement personnel, inaccurate measurement results, and low measurement efficiency. At the same time, as the measurement time goes by, it will cause the measurement personnel to be tired, resulting in increasing volatility in the measurement results, which may cause qualified parts to be judged as unqualified and unqualified parts to be judged as qualified, not only causing economic losses, but more seriously, it will cause product quality to be unqualified and cause safety hazards, even machine crashes and deaths. However, using the through-end plug gauge to measure can only ensure whether the chamfers at each location are qualified, but cannot measure the actual value of the chamfer size, and cannot compare the difference in the chamfer size at both ends. Although some products do not require the difference in the chamfer size at both ends, if this method is used for measurement and delivery, it may cause the asymmetry of the chamfers in actual use, causing the two ends of the part hole to be worn, affecting the product life, and causing both economic and reputation losses. This requires a set of measurement methods that can quickly and accurately measure the actual value of the hole chamfer size to meet the problem faced in production. Summary of the invention

[0005] The purpose of the present invention is to provide a chamfer measuring device with simple structure, high measuring efficiency, high measuring accuracy and easy maintenance in view of the problems of low measuring efficiency and inaccurate measuring of high-precision hole chamfer in the prior art.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows: a positioning cylindrical plug gauge 1 that can slide into the chamfered shaft hole is prepared, and a connecting rod 2 that extends horizontally along the shaft end of the positioning cylindrical plug gauge 1 and whose fixed end can be rotatably connected to the vertical direction of the positioning cylindrical plug gauge 1, a dial gauge 5 and a standard round plug gauge 4 for alignment are vertically fixed on the free end of the connecting rod 2; a step gauge ring with a diameter larger than the diameter of the hole to be measured is made on the shaft end of the positioning cylindrical plug gauge 1, the dial gauge on the free end of the connecting rod 2 is pivoted downward, and the dial gauge is rotated along the standard round plug gauge 4 through the mounting hole of the gauge frame. The upper end face of the circular plug gauge 4 slides in the vertical direction, the analog dial indicator pivot needle is aligned with the end face of the measured hole, and the dial indicator pivot needle is adjusted to "0", and the dial indicator and the connecting rod 2 are tightened and fixed with two fastening screws 3 respectively, which is defined as the starting point of the sinking of the measuring mandrel of the positioning cylindrical plug gauge 1; when measuring, the measuring mandrel of the positioning cylindrical plug gauge 1 slides along the measuring direction of the axis of the measured hole to the tip edge of the step gauge ring of the measuring mandrel, contacts the end hole of the chamfered cone surface to be measured, and forms a right triangle along the axis of the measured hole and the chamfer and end face of the hole, and calculates and measures the chamfer opening size parameters.

[0007] Compared with other current measurement technologies, the present invention has the following beneficial effects:

[0008] The operation is simple and the measuring efficiency is high. The present invention adopts a positioning cylindrical plug gauge 1 that can slide into the chamfered shaft hole, which extends horizontally along the shaft end of the positioning cylindrical plug gauge 1. The fixed end can be rotatably connected to the connecting rod 2 in the vertical direction of the positioning cylindrical plug gauge 1. The dial indicator 5 vertically fixed on the free end of the connecting rod 2 and the standard circular plug gauge 4 for alignment form a hole chamfering measuring fixture with a simple structure, few parts, and low manufacturing and cost of the measuring fixture: in this set of measuring fixtures, only the positioning part of the measuring mandrel has a matching relationship with the measured aperture, and the processing tolerances of other parts are relatively large, the manufacturing process is simple, and the processing quality and efficiency are high; the processing parameters can be adjusted according to the measurement results without the need for re-alignment. Compared with the existing three-coordinate, imager, through-stop plug gauge and the like, the cost is low, and the operation is simple and convenient, and the measuring efficiency is high.

[0009] Reliable positioning. The present invention adopts a step gauge ring with a diameter larger than the diameter of the measured hole on the shaft end of the positioning cylindrical plug gauge 1. The dial indicator on the free end of the connecting rod 2 is downwardly oriented and slides vertically along the upper end face of the standard circular plug gauge 4 through the mounting hole of the table frame. The analog dial indicator is aligned with the end face of the measured hole, and the dial indicator is adjusted to "0". The dial indicator and the connecting rod 2 are tightened and fixed with two fastening screws 3, which is defined as the starting point of the sinking of the measuring mandrel of the positioning cylindrical plug gauge 1. The positioning is reliable. The diameter change of the chamfered large end can be accurately displayed, so that the product can be easily and quickly tested.

[0010] The measurement is reliable and accurate. When the present invention is used for measurement, the measuring mandrel of the positioning cylindrical plug gauge 1 slides into the sharp edge of the step gauge ring of the measuring mandrel along the measuring direction of the axis of the measured hole, contacts the end hole of the chamfered cone surface to be measured, and forms a right triangle along the axis of the measured hole and the chamfer and end face of the hole mouth to calculate and measure the chamfer opening size. According to the simple calculation formula Dx=D+2tanα·X, after measuring X, the required chamfer hole mouth size can be directly calculated, avoiding the lack of resources of the three-coordinate system, and also avoiding the problem of inaccurate measurement caused by human energy problems in the imager during measurement.

[0011] Easy to maintain. The measuring fixture of the present invention is small and light: the measuring fixture is small, and there is no need to take the parts out of the machine tool, which is convenient for measuring the parts during the processing. Among the materials of the measuring fixture, only the measuring mandrel part is required to be wear-resistant, and there are no special requirements for other parts, and maintenance is simple. In the whole set of measuring fixtures, there is only a small fitting clearance between the measuring mandrel and the measured aperture, and the error of the measurement result can be controlled within 0.015. At the same time, the requirements for measurement personnel are also low, and there is no phenomenon of inaccurate measurement results due to lack of energy. Through this set of measuring fixtures, while ensuring the accuracy and efficiency of detection, the production resources of three-coordinate and imager are liberated, so that the three-coordinate and imager can be better invested in the measurement of other high-precision parts.

[0012] The invention can be widely used in measuring different parts, not only for measuring the chamfer dimensions of various orifices, but also for measuring the verticality between the end face and the inner hole, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a partial cross-sectional schematic diagram of the method for measuring the parameters of precision orifice chamfering.

[0014] Figure 2 yes Figure 1 Figure Schematic diagram of the survey bureau's cross section.

[0015] Figure 3 yes Figure 2 A partial enlarged schematic diagram of .

[0016] In the figure: 1 is the positioning cylindrical plug gauge, 2 is the connecting rod, 3 is the fastening screw, 4 is the standard round plug gauge, 5 is the dial indicator, and 6 is the part to be measured. DETAILED DESCRIPTION

[0017] See also Figure 1 , Figure 2. According to the present invention, a positioning cylindrical plug gauge 1 is prepared which can slide into the chamfered shaft hole, extends horizontally along the shaft end of the positioning cylindrical plug gauge 1, and the fixed end can be rotatably connected to the connecting rod 2 in the vertical direction of the positioning cylindrical plug gauge 1, as well as a dial indicator 5 and a standard round plug gauge 4 for alignment vertically fixed on the free end of the connecting rod 2. The diameter of the step gauge ring made on the shaft end of the positioning cylindrical plug gauge 1 is larger than the diameter of the measured hole. The dial indicator pivot needle on the free end of the connecting rod 2 is downward and slides vertically along the upper end face of the standard round plug gauge 4 through the mounting hole of the table frame, aligning the simulated dial indicator pivot needle with the end face of the measured hole mouth, and adjusting the dial indicator pivot needle to "0". Use two fastening screws 3 to tighten and fix the dial indicator and the connecting rod 2 respectively, which is defined as the starting point of the sinking of the measuring mandrel of the positioning cylindrical plug gauge 1; when measuring, the measuring mandrel of the positioning cylindrical plug gauge 1 slides into the measuring mandrel step gauge ring tip along the measuring direction of the measured hole axis to contact the measured chamfered cone end hole, forming a right triangle along the measured hole axis and the hole chamfer and hole end face, and calculating and measuring the hole chamfer opening dimension chain of the measured part 6. The diameter D at the tip of the step of the measuring mandrel gauge ring is used to form a right triangle dimension chain chamfer dimension chain formula Dx=D+2tanα·X, and the chamfer opening dimension chain parameters are calculated according to the angle α of the half-angle chamfer of the hole of the measured part 6 axis.

[0018] See also Figure 2 During measurement, tighten the mounting hole of the upper part of the table frame of the positioning cylindrical plug gauge 1 and the connecting rod 2 with the fastening screw 3 to ensure that the positioning cylindrical plug gauge 1 and the connecting rod 2 do not shake, and then fix the dial indicator on the connecting rod 2 with the fastening screw 3 at the other end of the connecting rod 2, so that it does not shake. The measuring direction of the dial indicator is the axis direction of the measured hole, and the needle is downward. Put the assembled measuring mandrel into the standard round plug gauge 4, align the analog dial indicator needle with the end face of the measured hole, and adjust the dial indicator needle to "0", which is defined as the starting point of the sinking of the measuring mandrel; then put the measuring mandrel of the positioning cylindrical plug gauge 1 into the measured hole, and use the characteristics that the diameter of the tip edge of the step gauge ring of the positioning cylindrical plug gauge 1 is larger than the diameter of the measured hole and smaller than the size of the chamfered hole of the hole, so that the measuring mandrel sinks along the axis direction of the hole until the tip edge of the step of the measuring mandrel gauge ring contacts the chamfered surface to be measured, and record the reading displayed on the dial indicator after the measuring mandrel sinks, which is the actual value X of the sinking of the measuring mandrel. Since the sinking path of the measuring mandrel is along the axis of the measured hole, it forms a right triangle with the chamfer and end face of the hole. According to the half-angle α of the chamfer of the hole of the measured part 6, the width L of the annular surface between the outer circle at the step of the measuring mandrel and the sharp edge of the chamfer opening can be calculated, that is: L = tanα·X, and finally the size of the chamfer opening Dx = D+2tanα·X is obtained, where D is the diameter of the sharp edge of the step of the measuring mandrel.

[0019] The specific operation can be carried out as described below: insert the dial indicator 5 onto the connecting rod 2, adjust the position of the dial indicator in the up and down direction so that the dial indicator 5 probe is lower than the step surface of the gauge ring of the positioning cylindrical plug gauge 1, and fix the dial indicator 5 and the connecting rod 2 with the fastening screws 3; then insert the connecting rod 2 into the positioning cylindrical plug gauge 1, adjust the position of the connecting rod in the left and right direction so that the dial indicator 5 probe is located outside the positioning cylindrical plug gauge 1 to prevent interference during measurement, and fix the connecting rod 2 and the positioning cylindrical plug gauge 1 with the fastening screws 3. Place the positioning cylindrical plug gauge 1 into the positioning hole of the standard circular plug gauge 4, and fit the step surface of the gauge ring of the positioning cylindrical plug gauge 1 tightly with the end face of the hole of the standard circular plug gauge 4. The pointer of the dial indicator 5 is adjusted to "0" with the end face of the hole of the standard circular plug gauge 4 as the reference, as the measurement starting point of the measuring fixture. At this time, pay attention to protect the installed measuring fixture to prevent the pointer of the dial indicator 5 from rotating due to collision, extrusion and other factors, resulting in inaccurate measurement results. Figure 1 The measuring mandrel of the positioning cylindrical plug gauge 1, which has been installed and adjusted to "0", is placed into the axial hole 5 of the measured part.

[0020] See also Figure 3 . The angle α of the half-angle chamfer of the hole of the measured part 6 and the sinking depth X of the positioning cylindrical plug gauge 1 in the measured part 6 form a right triangle calculation formula Dx=D+2tanα·X for measuring the chamfer opening size, where D is the diameter of the tip edge of the step gauge ring of the positioning cylindrical plug gauge 1. The dial indicator 5 selects the chamfered reference end face of the standard circular plug gauge 4 to fit the reference surface of the measured part 6. The positioning cylindrical plug gauge 1 measuring mandrel moves along the axis of the hole until the tip edge of the gauge ring step of the positioning cylindrical plug gauge 1 contacts the conical chamfered surface of the hole of the measured part 6, and it is determined that there is no offset between the chamfered surface of the measured hole and the inner hole wall. The measuring mandrel forms a right triangle dimension chain with the cone vertex angle formed by the chamfer of the hole and the sinking of the hole end along the axis of the measured hole. The actual value X of the data read on the dial indicator is obtained according to the sinking path of the measuring mandrel. Record the X value of the reading shown on dial indicator 5; use the right triangle dimension chain formed by the diameter D at the tip of the step of the measuring mandrel gauge ring, according to the angle α of the half-angle chamfer of the hole opening of the 6-axis of the measured part, and according to the chamfer dimension chain formula Dx=D+2tanα·X, calculate the actual value of the chamfer opening size Dx=D+2tanα·X and the width L of the annular surface between the outer circle of the step of the measuring mandrel gauge ring and the tip of the chamfer opening, that is: L=tanα·X.

[0021] This measuring tool can also be used to measure common apertures. As a further improvement to this embodiment.

[0022] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring the parameters of a precision hole chamfer, having the following technical features: preparing a positioning cylindrical plug gauge (1) that can slide into the chamfered shaft hole, and a connecting rod (2) extending horizontally along the shaft end of the positioning cylindrical plug gauge (1) and rotatably connected at the fixed end to the vertical direction of the positioning cylindrical plug gauge (1), a dial indicator (5) and a standard round plug gauge (4) for alignment are vertically fixed on the free end of the connecting rod (2); a step gauge ring having a diameter greater than the diameter of the hole to be measured is made on the shaft end of the positioning cylindrical plug gauge (1), and the dial indicator on the free end of the connecting rod (2) is pivoted downward. Slide along the upper end face of the standard round plug gauge (4) in the vertical direction through the mounting hole of the gauge frame, align the analog dial indicator's pivot needle with the end face of the hole to be measured, and adjust the dial indicator's pivot needle to "0". Use two fastening screws (3) to tighten and fix the dial indicator and the connecting rod (2) respectively, which is defined as the starting point of the sinking of the measuring mandrel of the positioning cylindrical plug gauge (1); when measuring, the measuring mandrel of the positioning cylindrical plug gauge 1 slides along the measuring direction of the axis of the hole to be measured to the sharp edge of the measuring mandrel step gauge ring, contacts the end hole of the chamfered cone surface to be measured, and forms a right triangle along the axis of the hole to be measured and the chamfer and end face of the hole to be measured, and calculates and measures the chamfer opening size parameters.

2. The method for measuring precision orifice chamfer parameters according to claim 1, characterized in that: The positioning cylindrical plug gauge (1) is placed in the positioning hole of the standard round plug gauge (4), so that the step surface of the cylindrical plug gauge 1 is closely fitted to the end face of the hole of the standard round plug gauge (4), and the pointer of the dial indicator (5) is adjusted to "0" with the end face of the hole of the standard round plug gauge (4) as the reference, which serves as the measurement starting point of the measuring fixture.

3. The method for measuring precision orifice chamfer parameters as claimed in claim 1, characterized in that: The diameter D at the tip of the step of the measuring mandrel gauge ring, the angle α of the half-angle chamfer of the axial hole of the measured part (6) and the sinking depth X of the positioning cylindrical plug gauge (1) in the measured part (6) form a right triangle calculation formula Dx=D+2tanα·X for measuring the chamfer opening size, wherein D is the diameter of the tip of the mandrel step gauge ring measured by the positioning cylindrical plug gauge.

4. The method for measuring precision orifice chamfer parameters according to claim 1, wherein: The dial indicator (5) selects the chamfered reference end face of the standard circular plug gauge (4) to fit the reference surface of the measured part (6), and the measuring mandrel of the positioning cylindrical plug gauge (1) moves along the hole axis until the tip of the gauge ring step of the positioning cylindrical plug gauge (1) contacts the conical chamfered surface of the hole mouth of the measured part (6). The measuring mandrel sinks along the axis of the measured hole and the chamfered and hole mouth end to form a right triangle dimension chain, and the actual value X of the data read on the dial indicator is obtained according to the sinking path of the measuring mandrel.

5. The method for measuring precision orifice chamfer parameters as claimed in claim 1, characterized in that: Using the right triangle dimension chain formed by the diameter D at the tip of the step of the measuring mandrel gauge ring, according to the angle α of the half-angle chamfer of the 6-axis hole of the measured part, the chamfer dimension chain formula Dx=D+2tanα·X is used to calculate the actual value of the chamfer opening size Dx=D+2tanα·X and the width L of the annular surface between the outer circle of the step of the measuring mandrel gauge ring and the tip of the chamfer opening, that is: L=tanα·X.

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