A special inspection tool and inspection method for depth micrometer

Abstract

A special inspection tool and method for calibrating a depth micrometer includes a rectangular measuring block and a standard steel ball. The rectangular measuring block has several groups of circular grooves of different sizes on its outer surface, each with a spherical arc bottom. Several groups of standard steel balls are provided, each with a diameter corresponding to the circular grooves of different sizes. The roughness Ra of the outer surface of the rectangular measuring block, the bottom of the circular grooves, and the surface of the standard steel balls is less than 0.1 mm. By designing the combined structure of the standard measuring block and standard steel balls and innovating a method for testing the parallelism between the measuring surface of the depth micrometer base plate and the measuring surface of the measuring rod, the present invention achieves the goals of ensuring the accuracy of test results and improving work efficiency.

Description

Technical Field

[0001] The present invention relates to a checking tool and a calibration method, in particular to a special checking tool and a calibration method for detecting the parallelism between a measuring rod measuring surface and a bottom plate measuring surface during the calibration process of a depth micrometer. Background Art

[0002] As attached Figure 1 As shown, a depth micrometer 1 utilizes the principle of a screw pair to measure the distance between the measuring surface of a base plate and the measuring surface of a measuring rod. It consists of a differential cylinder 1-1, a fixed sleeve 1-2, a measuring rod 1-3, a base plate 1-4, and a locking device 1-5. It is primarily used to measure the depth, steps, and other dimensions of precision workpieces during machining. For depth micrometers with a flat measuring surface of the measuring rod 1-3, the parallelism between the measuring surfaces of the base plate 1-4 and the measuring rod 1-3 significantly affects the accuracy of the measurement results. Therefore, in the national standard verification procedures for depth micrometers, parallelism between the measuring surfaces of the measuring rod and base plate is a mandatory inspection item and a verification veto. That is, if this item fails verification, the entire micrometer is scrapped.

[0003] In the national standard verification procedure, the parallelism test between the measuring surface of the measuring rod and the measuring surface of the base plate adopts the standard steel ball detection method. By changing the position of the steel ball 3, different position points of the measuring surface of the measuring rod 1-1 in the depth micrometer 1 are brought into contact with the standard steel ball 3, thereby obtaining a set of measurement data. The measurement data is compared with the diameter size of the standard steel ball 3 to obtain the parallelism deviation between the measuring surface of the measuring rod 1-1 of the depth micrometer and the measuring surface of the base plate 1-2. Since the steel ball 3 is directly placed on the platform 4 during the detection process, it is very easy to roll back and forth. Not only is the position of the steel ball 3 difficult to control, the work efficiency is low, but it is also easy to scratch the platform 4. The standard detection procedure has very high requirements for the roughness of the surface of the platform 4. If the platform 4 is scratched, the measurement standard will be inaccurate, resulting in poor accuracy of the detection results. Summary of the Invention

[0004] The present invention provides a special inspection tool and inspection method for calibrating a depth micrometer. The invention aims to achieve the purpose of ensuring the accuracy of the inspection results and improving work efficiency by designing a combined structure of a standard measuring block and a standard steel ball and innovating a method for inspecting the parallelism between the measuring surface of the depth micrometer base plate and the measuring surface of the measuring rod.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A special gauge for calibrating depth micrometers comprises a rectangular measuring block and a standard steel ball. The rectangular measuring block is provided with a plurality of groups of circular grooves of different sizes on its outer surface, and the bottom surfaces of the circular grooves are spherical arc surfaces. The standard steel balls are provided in a plurality of groups, and their diameters correspond to the circular grooves of different sizes. The roughness Ra of the outer surface of the rectangular measuring block, the bottom surfaces of the circular grooves, and the surface of the standard steel balls is less than 0.1 mm.

[0007] The above-mentioned special inspection tool for depth micrometer calibration is provided with an anti-slip structure on the side surface of the rectangular measuring block.

[0008] The above-mentioned special inspection tool for depth micrometer calibration has the anti-skid structure consisting of long anti-skid grooves running through the upper end surface and the bottom surface, and the number of the long anti-skid grooves is no less than two groups.

[0009] The anti-slip structure of the above-mentioned special gauge for calibrating depth micrometers is a group of circular grooves arranged in a straight line along the vertical axis.

[0010] A depth micrometer calibration method, using the above-mentioned special inspection tool to complete the parallelism inspection of the measuring surface of the depth micrometer's measuring rod and the measuring surface of the base plate, includes the following steps:

[0011] a. Positioning the depth micrometer: First, select two gauge blocks whose dimensions match the range of the depth micrometer to be calibrated. Place the two gauge blocks parallel to each other on a flat plate. Then, place the base plate of the depth micrometer to be calibrated on the two gauge blocks, so that the measuring surface of the base plate of the depth micrometer fits in contact with the upper end faces of the two gauge blocks.

[0012] b. Select the circular groove and standard steel ball on the rectangular measuring block. According to the measuring range of the depth micrometer to be calibrated, select a circular groove and standard steel ball of a certain size on the rectangular measuring block;

[0013] c. Place the rectangular measuring block with the circular groove of the selected size upward, place the selected standard steel ball in the circular groove of the selected size, and then place the rectangular measuring block and the standard steel ball between the two gauge blocks on the flat plate;

[0014] d. Move the rectangular measuring block so that the standard steel ball contacts four points on the front, back, left, and right of the measuring surface of the depth micrometer being calibrated, and read the readings at the four measuring points respectively.

[0015] e. Calculate the difference between the maximum and minimum readings at the four measurement points;

[0016] f. Repeat steps d and e to calculate the average of the differences between the maximum and minimum values, and correct the average to obtain the parallelism value between the measuring surface of the depth micrometer rod and the measuring surface of the base plate;

[0017] g. Compare the parallelism value between the measuring surface of the depth micrometer rod and the measuring surface of the base plate with the standard setting value to determine whether the depth micrometer being tested is qualified, thus completing the depth micrometer calibration process.

[0018] In the above-mentioned depth micrometer calibration method, the ambient temperature when testing the parallelism between the measuring surface of the depth micrometer's measuring rod and the measuring surface of the base plate is 20±5°C.

[0019] In the above-mentioned depth micrometer calibration method, in step a, the two gauge blocks are located 3-5 mm away from the edge of the bottom plate measuring surface of the depth micrometer being calibrated.

[0020] In the above-mentioned depth micrometer calibration method, in step f, the measurement is repeated ten times.

[0021] The present invention provides a special inspection tool and inspection method for depth micrometer calibration. In the special inspection tool for depth micrometer calibration, the diameter of the circular groove provided on the outer surface of the rectangular measuring block is slightly larger than the diameter of the standard steel ball of the corresponding diameter size, so that the standard steel ball can rotate in the circular groove and realize the self-centering effect of the standard steel ball, thereby ensuring the consistency of the height of the contact point between the standard steel ball and the measuring surface of the depth micrometer measuring rod during the measurement process, thereby ensuring the accuracy of the measurement result; the roughness Ra of the outer surface of the rectangular measuring block, the bottom surface of the groove and the surface of the standard steel ball of the special inspection tool for depth micrometer calibration of the present invention is less than 0.1mm, so when measuring the measuring surface of the depth micrometer measuring rod and the bottom surface, the standard steel ball is aligned with the standard steel ball. When testing the parallelism of the plate measuring surface, the special inspection tool can be placed between the flat plate and the measuring surface of the measuring rod, which can not only limit the position of the standard steel ball, but also enable the operator to complete the inspection project independently, avoiding the measurement error caused by the steel ball sliding on the flat plate; in addition, an anti-slip structure is set on the side elevation of the rectangular measuring block in the special inspection tool for depth micrometer calibration described in the present invention, avoiding the problem of the rectangular measuring block falling and scratching the flat plate when placed due to the operator's hand slipping, ensuring the flatness of the measurement reference, and especially adopting a group of circular grooves arranged in a straight line as the anti-slip structure, so that it not only has an anti-slip function, but can also be used for positioning standard steel balls of certain diameter sizes, thereby enhancing its universal performance. In summary, the present invention has achieved the purpose of ensuring the accuracy of the test results and improving work efficiency by designing the combined structure of the standard measuring block and the standard steel ball and innovating a method for detecting the parallelism between the measuring surface of the bottom plate of the depth micrometer and the measuring surface of the measuring rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the standard verification procedure for depth micrometers;

[0023] Figure 2 This is a schematic diagram of the structure of the special inspection tool for depth micrometer calibration described in the present invention;

[0024] Figure 3 yes Figure 2 Schematic diagram of the explosion structure;

[0025] Figure 4 This is a schematic diagram of the cross-sectional structure of a special gauge for depth micrometer calibration;

[0026] Figure 5 yes Figure 2 K-direction view;

[0027] Figure 6 It is a schematic diagram of the working state of the special inspection tool for depth micrometer verification described in the present invention.

[0028] The list of reference numbers in the figure is:

[0029] 1. Depth micrometer, 1-1. Differential cylinder, 1-2. Fixed sleeve, 1-3. Measuring rod, 1-4. Base plate, 1-5. Locking device;

[0030] 2. Gauge block;

[0031] 3. Standard steel ball;

[0032] 4. Tablet;

[0033] 5. Rectangular measuring block, 5-1. Circular groove, 5-2. Anti-slip long groove. DETAILED DESCRIPTION

[0034] The present invention provides a special inspection tool and inspection method for calibrating a depth micrometer, and in particular, provides a special inspection tool and inspection method for detecting the parallelism between the measuring surface of a measuring rod and the measuring surface of a base plate during the calibration process of the depth micrometer. The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0035] See Figure 2. Figure 3 、 Figure 4 、 Figure 5 The special inspection tool for depth micrometer calibration described in the present invention includes a rectangular measuring block 5 and a standard steel ball 3; the rectangular measuring block 5 is provided with a plurality of groups of circular grooves 5-1 of different sizes on its outer surface, and the bottom surface of the circular grooves 5-1 is a spherical arc surface; the standard steel balls 3 are arranged in a plurality of groups, and their diameters correspond to the circular grooves 5-1 of different sizes; the roughness Ra of the outer surface of the rectangular measuring block 5, the bottom surface of the circular grooves 5-1 and the surface of the standard steel balls 3 is less than 0.1mm.

[0036] See Figure 2. Figure 3 The special inspection tool for depth micrometer calibration described in the present invention is provided with an anti-slip structure on the side surface of the rectangular measuring block 5; a first preferred embodiment of the anti-slip structure is an anti-slip long groove 5-2 running through the upper end surface and the bottom surface, and the number of the anti-slip long grooves 5-2 is not less than two groups.

[0037] See Figure 2 、 Figure 5 The second preferred embodiment of the anti-slip structure of the special inspection tool for depth micrometer calibration described in the present invention is a group of circular grooves arranged in a straight line along the vertical axis.

[0038] See Figure 1 In the national standard verification procedure for depth micrometers, the parallelism test between the measuring surface of the measuring rod and the measuring surface of the base plate adopts the standard steel ball detection method, that is, by changing the position of the steel ball 3, different position points of the measuring surface of the measuring rod 1-1 in the depth micrometer 1 are made to contact the standard steel ball 3, thereby obtaining a set of measurement data. The measurement data is compared with the diameter size of the standard steel ball 3 to obtain the parallelism deviation between the measuring surface of the measuring rod 1-1 of the depth micrometer and the measuring surface of the base plate 1-2. Since the steel ball 3 is directly placed on the platform 4 during the detection process, it is very easy to roll back and forth. Not only is the position of the steel ball 3 difficult to control, the work efficiency is low, but it is also easy to scratch the platform 4. The standard detection procedure has very high requirements for the roughness of the surface of the platform 4. Once the platform 4 is scratched, the measurement standard will be inaccurate, resulting in poor accuracy of the detection results.

[0039] See Figure 6 The depth micrometer calibration method of the present invention uses the above-mentioned special depth micrometer calibration fixture to complete the parallelism test of the measuring surface of the measuring rod 1-3 of the depth micrometer 1 and the measuring surface of the base plate 1-4. The ambient temperature during the parallelism test of the measuring surface of the measuring rod 1-3 of the depth micrometer and the measuring surface of the base plate is controlled at 20±5°C. The specific operating steps are as follows:

[0040] a. Positioning the depth micrometer: First, select two gauge blocks 2 whose dimensions match the range of the depth micrometer being calibrated. Place the two gauge blocks 2 parallel to each other on the flat plate 4. Then, place the base plate 1-4 of the depth micrometer being calibrated on the two gauge blocks 2, ensuring that the measuring surface of the base plate 1-4 of the depth micrometer 1 is aligned with the upper end surfaces of the two gauge blocks 2. The two gauge blocks 2 are positioned 3-5 mm from the edge of the measuring surface of the base plate 1-4 of the depth micrometer being calibrated.

[0041] b. Select the circular groove 5-1 and the standard steel ball 3 on the rectangular measuring block 5. According to the measuring range of the depth micrometer 1 to be calibrated, select the circular groove 5-1 and the standard steel ball 3 of a certain size on the rectangular measuring block 5;

[0042] c. Place the rectangular measuring block 5 with the circular groove of the selected size facing upwards, place the selected standard steel ball 3 in the circular groove 5-1 of the selected size, and then place the rectangular measuring block 5 and the standard steel ball 3 between the two gauge blocks 2 on the flat plate 4;

[0043] d. Move the rectangular measuring block 5 so that the standard steel ball 3 contacts four points on the front, back, left, and right sides of the measuring surface of the measuring rod 1-3 of the depth micrometer 1 to be calibrated, and read the readings at the four measuring points respectively;

[0044] e. Calculate the difference between the maximum and minimum readings at the four measurement points;

[0045] f. Repeat steps d and e ten times, calculate the average of the difference between the maximum and minimum values, and correct the average to obtain the parallelism value between the measuring surface of the depth micrometer rod and the measuring surface of the base plate;

[0046] g. Compare the parallelism value between the measuring surface of the depth micrometer rod and the measuring surface of the base plate to the standard setting value to determine whether the depth micrometer 1 is qualified, thus completing the verification process of the depth micrometer.

Claims

1. A special inspection tool for depth micrometer calibration, characterized by: It comprises a rectangular measuring block (5) and a standard steel ball (3); the rectangular measuring block (5) is provided with a plurality of groups of circular grooves (5-1) of different sizes on its outer surface, and the bottom surface of the circular groove (5-1) is a spherical arc surface; the standard steel ball (3) is configured in a plurality of groups, the diameter of the circular groove (5-1) provided on the outer surface of the rectangular measuring block (5) is slightly larger than the diameter of the standard steel ball (3) of the corresponding diameter size, and the standard steel ball (3) can rotate in the circular groove (5-1), and the roughness Ra of the outer surface of the rectangular measuring block (5), the bottom surface of the circular groove (5-1) and the surface of the standard steel ball (3) is less than 0.1 mm.

2. The special gauge for depth micrometer calibration according to claim 1 is characterized in that: An anti-slip structure is provided on the side elevation of the rectangular measuring block (5).

3. The special gauge for calibrating a depth micrometer according to claim 2, characterized in that: The anti-skid structure is an anti-skid long groove (5-2) that passes through the upper end surface and the bottom surface, and the number of the anti-skid long grooves (5-2) is no less than two groups.

4. The special gauge for calibrating a depth micrometer according to claim 2, characterized in that: The anti-slip structure is a group of circular grooves arranged in a straight line along the vertical axis.

5. A method for calibrating a depth micrometer, comprising the steps of: detecting the parallelism between the measuring surface of a measuring rod (1-3) of a depth micrometer and the measuring surface of a base plate (1-4) using a special calibrating tool for calibrating a depth micrometer as claimed in any one of claims 1 to 4; and comprising the steps of: a. Positioning the depth micrometer: First, select two gauge blocks (2) whose size specifications match the range of the depth micrometer to be calibrated, place the two gauge blocks (2) in parallel on the flat plate (4), and then place the base plate (1-4) of the depth micrometer (1) to be calibrated on the two gauge blocks (2) so that the measuring surface of the base plate (1-4) of the depth micrometer (1) fits in with the upper end surfaces of the two gauge blocks (2); b. Select the circular groove (5-1) and the standard steel ball (3) on the rectangular measuring block (5). According to the measuring range of the depth micrometer (1) to be calibrated, select the circular groove (5-1) and the standard steel ball (3) of a certain size on the rectangular measuring block (5); c. With the side of the rectangular measuring block (5) provided with the circular groove of the selected size and specification facing upward, and after placing the selected standard steel ball (3) in the circular groove (5-1) of the selected size and specification, the rectangular measuring block (5) and the standard steel ball (3) are placed between the two gauge blocks (2) on the flat plate (4); d. Move the rectangular measuring block (5) so that the standard steel ball (3) contacts the four points at the front, rear, left and right of the measuring surface of the measuring rod (1-3) of the depth micrometer (1) to be calibrated, and read the readings of the four measuring points respectively; e. Calculate the difference between the maximum and minimum readings at the four measurement points; f. Repeat steps d and e to calculate the average of the differences between the maximum and minimum values, and correct the average to obtain the parallelism value between the measuring surface of the depth micrometer rod and the measuring surface of the base plate; g. Compare the parallelism value between the measuring surface of the depth micrometer rod and the measuring surface of the base plate to be calibrated with the standard setting value to determine whether the depth micrometer (1) to be tested is qualified, and complete the calibration process of the depth micrometer.

6. The depth micrometer calibration method according to claim 5, characterized in that: The ambient temperature when testing the parallelism between the measuring surface of the depth micrometer's measuring rod and the measuring surface of the base plate is 20±5℃.

7. The depth micrometer calibration method according to claim 6, wherein In step a, the two gauge blocks (2) are located 3-5 mm away from the edge of the measuring surface of the bottom plate (1-4) of the depth micrometer (1) to be calibrated.

8. The depth micrometer calibration method according to claim 6, wherein: In the step f, the measurement is repeated ten times.

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