Convenient diameter gauge

Abstract

This utility model discloses a convenient diameter measuring tool, including a dial indicator, a base, and a dial indicator adjustment mechanism. The adjustment mechanism includes a base, a lever, and a probe III that contacts the inner wall of the measured part. The probe III is fixedly installed on the bottom surface of the base, and the base is installed on the top surface of the base. The base has an internal cavity structure. The dial indicator is connected to the base, and the measuring end of the dial indicator abuts against the lever downwards. The lever includes a measuring rod and a trigger rod arranged perpendicularly to each other. The end of the measuring rod is provided with a probe II that contacts the inner wall of the measured part, and the end of the trigger rod contacts the probe I of the dial indicator. The lever and the base are connected via a rotating joint. The distance from the contact point of the probe I and the trigger rod to the center of the rotating joint is equal to the distance from the contact point of the probe II and the measured part to the center of the rotating joint. This utility model has a simple structure and low manufacturing cost; it is easy to operate, has high measurement accuracy, and high measurement efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of measuring instrument technology, specifically relating to a convenient diameter measuring instrument for measuring the diameter of the inner circular groove of ring-shaped parts of aero-engines. Background Technology

[0002] The internal dimensions of sealing rings and end caps for aero-engines require high precision. Currently, the main methods for measuring the inner diameter and length of these components are coordinate measuring machines (CMMs) or calipers. However, CMMs are costly, require computer-aided measurement, are time-consuming, and have very low efficiency, severely impacting component delivery. Calipers, on the other hand, offer lower precision and are less accurate in measuring precise dimensions. Summary of the Invention

[0003] To solve the above-mentioned technical problems, this utility model provides a convenient diameter measuring tool with simple structure, low manufacturing cost, convenient measurement, high measurement accuracy, low measurement cost, and improved measurement efficiency.

[0004] The technical solution adopted by this utility model is as follows: a convenient diameter measuring tool, including a dial indicator, a base, and a matching mechanism; the matching mechanism includes a base, a lever, and a probe III that contacts the inner wall of the measured part; the probe III is fixedly installed on the bottom surface of the base, and the base is installed on the top surface of the base; the base has an internal cavity structure, the dial indicator is connected to the base, and the measuring end of the dial indicator abuts against the lever downwards; the lever includes a measuring rod and a trigger rod arranged perpendicularly to each other, the end of the measuring rod is provided with a probe II that contacts the inner wall of the measured part, the end of the trigger rod contacts the probe I of the dial indicator, the lever and the base are connected by a rotating joint, and the distance from the contact point of the probe I and the trigger rod to the center of the rotating joint is equal to the distance from the contact point of the probe II and the measured part to the center of the rotating joint;

[0005] Furthermore, the rotating pair includes a pin, which is interference-fitted with the base and clearance-fitted with the lever, with a clearance of 0.003mm to 0.005mm; the probe I, the probe II, and the probe III are located in the same plane.

[0006] Furthermore, the base is provided with a support surface, which supports the workpiece to be tested. The flatness of the support surface is not greater than 0.005mm, and the surface roughness is not greater than Ra0.4μm.

[0007] Furthermore, the surface roughness of the side of the pin is no greater than Ra0.4μm, and the surface roughness of the pin hole of the lever is no greater than Ra0.4μm.

[0008] Furthermore, the inner cavity of the dial indicator base includes a central hole and a trigger rod rotating cavity that are interconnected. The central hole is a stepped hole, with the upper diameter larger than the middle diameter and the lower diameter larger than the middle diameter. The upper part of the central hole is interference-fitted with the steel sleeve, and the steel sleeve is clearance-fitted with the dial indicator. The sidewalls of the steel sleeve and the central hole are respectively provided with set screw hole I and set screw hole II, which are coaxial. The set screw is installed in set screw hole I and set screw hole II to tighten the dial indicator. A spring is provided between the stepped surface of the lower part of the central hole and the trigger rod, and the spring is sleeved on the measuring rod of the dial indicator.

[0009] Furthermore, the coaxiality of the inner and outer circles of the steel sleeve is no greater than 0.01 mm, and the surface roughness of the steel sleeve is no greater than Ra0.8 μm.

[0010] Furthermore, the lever is made of mold steel, and its hardness is not less than 55HRC.

[0011] Furthermore, the base is provided with screw holes, which are coaxial with the center hole. Screws are installed in the screw holes, and the top surface of the screws contacts the bottom surface of the trigger rod for adjusting and limiting the lever.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] This invention features a simple structure and low manufacturing cost. In use, the base is placed flat in the inner hole of the dial indicator by operating the lever, and the dial indicator is zeroed. Then, it is removed and placed in the inner hole of the part being measured using the same method. The dial indicator reading then accurately determines the size of the workpiece. The operation is simple, with high measurement accuracy and efficiency, and the cost is lower than that of coordinate measuring machines. Attached Figure Description

[0014] Figure 1 This is a structural diagram of the present invention.

[0015] Figure 2 This is a structural diagram of the present invention used for measuring workpieces.

[0016] Figure 3 It is a workpiece with a honeycomb structure being measured. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] like Figure 1-2As shown, this utility model includes a dial indicator 1, a base 2, and a dial indicator setting mechanism. The setting mechanism includes a dial indicator base 3, a lever 4, and a probe III 5. The base 2 is a rod-shaped structure, with the probe III 5 fixedly mounted at one end of its bottom surface. The base 2 has a support surface that supports the workpiece to be measured. The flatness of the support surface is no greater than 0.005 mm, and the surface roughness is no greater than Ra 0.4 μm, ensuring a smooth and even surface. The dial indicator base 3 is welded to the top surface of the other end of the base 2. A lever 4 is hinged to the dial indicator base 3 via a pin 6. The lever 4 includes a measuring rod 41, a trigger rod 42, and a handle rod 43, forming a Y-shaped structure. The measuring rod 41 is perpendicular to the trigger rod 42. The pin 6 is fixedly mounted on the base 3. The pin hole of the lever 4 is clearance-fitted with the pin 6, ensuring a clearance between 0.003mm and 0.005mm. The surface roughness of the side of the pin 6 is no greater than Ra0.4μm, and the surface roughness of the pin hole of the lever 4 is no greater than Ra0.4μm. This ensures a precise fit and flexible rotation. The pin 6 and the base 3 are interference-fitted. The lever 4 is made of mold steel with a hardness of no less than 55HRC, thus avoiding measurement errors caused by deformation during use. The base 2 has a measuring rod hole 21 corresponding to the measuring rod. The end of the measuring rod passes through the measuring rod hole 21. A measuring head II 44 is located on the side of the measuring rod 41 facing away from the measuring head III 5. The measuring head III 5 and the measuring head II 44 are used to contact the inner wall of the inner hole to be measured.

[0019] The gauge base 3 has an internal cavity structure, including a central hole and a trigger rod rotation cavity that are interconnected. The axis of the central hole is perpendicular to the top surface of the base 5. A dial indicator 1 is mounted on the gauge base 3. The probe I of the dial indicator 1 passes through the central hole and contacts the top surface of the end of the trigger rod 42. The distance from the pin 6 to the probe II 44 is equal to the distance from the pin 6 to the probe I. Probe I, probe II 44, and probe III 5 are located in the same plane. The central hole is a stepped hole, with the upper diameter larger than the middle diameter and the lower diameter larger than the middle diameter. The upper part of the central hole is interference-fitted with the steel sleeve 7, and the steel sleeve 7 is clearance-fitted with the dial indicator 1. The coaxiality of the inner and outer circles of the steel sleeve 7 is no greater than 0.01 mm, and the surface roughness is ≤ Ra 0.8 μm. Set screw holes I and II are respectively provided on the sidewalls of the steel sleeve 7 and the central hole, and the set screw holes I and II are coaxial. Set screw 8 is installed in set screw holes I and II, pressing against dial indicator 1 to position and fix dial indicator 1. A spring 9 is provided between the stepped surface at the lower part of the center hole and the trigger rod, and the spring 9 is sleeved on the measuring rod of dial indicator 1.

[0020] The base 2 is provided with screw holes, which are coaxial with the center hole. A screw 10 is installed in the screw hole, and the top surface of the screw 10 contacts the bottom surface of the trigger rod. The screw 10 is used to adjust and limit the lever 4.

[0021] In use, the base 2 is placed flat in the inner hole of the dial indicator 11 by operating the lever 4. First, the dial indicator 11 is measured and zeroed. Then, it is removed and placed in the inner hole of the part being measured using the same method. The dial indicator reading at this time is the difference between the inner hole size of the part being measured and the inner hole size of the dial indicator 11. The size of the workpiece being measured can be accurately obtained by adding the inner hole size of the dial indicator 11 to the dial indicator reading.

[0022] The dial indicator 11 is made of CrWMn material, with a hardness of not less than 55HRC after heat treatment, ensuring high rigidity, resistance to deformation, and wear resistance. The surface roughness of the inner hole and the support surface is not greater than Ra0.4μm, and the perpendicularity tolerance between the support surface and the inner hole is 0.005mm, reducing installation and dial indicator errors. The dial indicator 11 is used in conjunction with this invention. The inner hole diameter "D" of the dial indicator 11 is accurately measured using a precision coordinate measuring machine, and the measured value is imprinted in a conspicuous place on the dial indicator for easy viewing by the user.

[0023] The probe II44 of probe III5 and lever 4 can be designed with different shapes to meet different measurement conditions, such as when the part being measured is... Figure 3 When the honeycomb structure is shown, cylindrical probes III5 and II44 can be designed according to the width of the honeycomb to avoid the problem of excessive measurement values ​​caused by probes III5 and II44 being trapped in the honeycomb holes. The shape of probes III5 and II44 can be flexibly changed for other special structures.

[0024] Through measurement of multiple batches of parts, the error compared with the coordinate measuring machine (CMM) results is ≤0.005mm, indicating good consistency. This method enables quick and convenient part measurement, solving the problems of low waiting efficiency and CMM point fitting errors, as well as the difficulty of finding the optimal measurement point and low accuracy of caliper measurements. This invention is easy to use and disassemble. Different specifications and sizes, as well as different probe shapes (Ⅲ5 and Ⅱ44), can be designed according to the different conditions of the parts being measured, offering good versatility and consistent part quality.

Claims

1. A portable diameter gauge comprising a dial gauge, a base and a dial mechanism; characterized in that: The dial indicator mechanism includes a base, a lever, and a probe III that contacts the inner wall of the measured part. The probe III is fixedly installed on the bottom surface of the base, and the base is installed on the top surface of the base. The base has an internal cavity structure, and the dial indicator is connected to the base, with the measuring end of the dial indicator pointing downwards and abutting against the lever. The lever includes a measuring rod and a trigger rod arranged perpendicularly to each other. The end of the measuring rod is provided with a probe II that contacts the inner wall of the measured part, and the end of the trigger rod contacts the probe I of the dial indicator. The lever and the base are connected by a rotating joint, and the distance from the contact point of the probe I and the trigger rod to the center of the rotating joint is equal to the distance from the contact point of the probe II and the measured part to the center of the rotating joint.

2. The portable diameter gauge of claim 1, wherein: The rotating pair includes a pin, which is interference-fitted with the base and clearance-fitted with the lever, with a clearance of 0.003mm to 0.005mm; the probe I, the probe II, and the probe III are located in the same plane.

3. The portable diameter gauge of claim 1, wherein: The base is provided with a support surface, which supports the workpiece to be tested. The flatness of the support surface is not greater than 0.005mm and the surface roughness is not greater than Ra0.4μm.

4. The portable diameter gauge of claim 2, wherein: The surface roughness of the side of the pin is no greater than Ra0.4μm, and the surface roughness of the pin hole of the lever is no greater than Ra0.4μm.

5. The convenient diameter measuring tool according to claim 1, characterized in that: The inner cavity of the dial indicator base includes a central hole and a trigger rod rotating cavity that are interconnected. The central hole is a stepped hole, with the upper diameter larger than the middle diameter and the lower diameter larger than the middle diameter. The upper part of the central hole is interference-fitted with the steel sleeve, and the steel sleeve is clearance-fitted with the dial indicator. The sidewalls of the steel sleeve and the central hole are respectively provided with set screw hole I and set screw hole II, which are coaxial. The set screw is installed in set screw hole I and set screw hole II to tighten the dial indicator. A spring is provided between the stepped surface of the lower part of the central hole and the trigger rod, and the spring is sleeved on the measuring rod of the dial indicator.

6. The convenient diameter measuring tool according to claim 5, characterized in that: The coaxiality of the inner and outer circles of the steel sleeve is no greater than 0.01 mm, and the surface roughness of the steel sleeve is no greater than Ra0.8 μm.

7. The portable diameter gauge of claim 1, wherein: The lever is made of mold steel, and its hardness is not less than 55HRC.

8. The portable diameter gauge of claim 1, wherein: The base is provided with screw holes, which are coaxial with the center hole. Screws are installed in the screw holes, and the top surface of the screws contacts the bottom surface of the trigger rod for adjusting and limiting the lever.

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