Inner diameter measuring device and measuring method

Abstract

The invention discloses an inner diameter measuring device and an inner diameter measuring method. The device comprises a measuring device main body, a vertical lifting mechanism, a rotating table and a working table, the rotating table is rotatably installed on the workbench and used for fixedly installing a to-be-tested piece so as to drive the to-be-tested piece to rotate together. The measuring device body comprises a horizontal displacement measuring head, a horizontal measuring head sealing sleeve, a shell, an air pipe, a vertical displacement measuring head and a vertical measuring head sealing sleeve. According to the method, firstly, an inner diameter measuring device is built, then a displacement measuring head measures data, then inner diameter values of all measuring positions are obtained through calculation, and the average value of the inner diameter values of all the measuring positions is adopted as the final inner diameter value of a to-be-measured piece. The three-point type inner diameter measuring device is used for measuring the inner diameter data, the elliptic equation is used for solving the inner diameter, automatic mechanical three-point type inner diameter measurement is achieved, various errors are comprehensively considered, and the measuring efficiency and the measuring precision are improved.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, in particular to an inner diameter measuring device and a measuring method. Background Art

[0002] The automotive manufacturing, aerospace and other fields all have extremely high requirements for the geometric manufacturing accuracy of parts and components. Among them, the inner diameter processing accuracy has a direct impact on the overall quality of the corresponding parts and components, and is directly related to the life, stability and safety of the entire mechanism system. Therefore, improving the inner diameter measurement accuracy is very important.

[0003] Due to the harsh on-site environment of automated production lines, high-precision inner diameter measuring devices are generally difficult to install on production lines for automated measurement, so manual inspection methods are commonly used. However, manual inspection methods are not only inefficient, but also prone to human errors. Therefore, high-precision and high-efficiency measurement of inner diameters has always been a difficult problem to solve in parts production inspection.

[0004] The current automated inner diameter measurement has the following problems: 1. Due to the limitation of mechanical structure, the existing mechanical inner diameter measuring devices used in automation are divided into one-point type and two-point type, and there is a lack of three-point inner diameter measuring devices. 2. In automated production lines, due to the existence of various errors, the conventional mechanical linkage multi-probe measuring device has the phenomenon that the probe cannot contact the workpiece to be measured, which is not suitable for automated production lines. 3. The inner diameter measurement method usually uses the method of solving the circle equation to solve the inner diameter, but due to the error, there is an angle between the inner diameter measurement plane and the plane of the workpiece to be measured, so there is a calculation error in the measurement method. Summary of the invention

[0005] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an inner diameter measuring device and a measuring method.

[0006] The technical solution of the present invention to solve the technical problem is to provide an inner diameter measuring device, characterized in that the device comprises a measuring device body, a vertical lifting mechanism, a rotating table and a workbench; the rotating table is rotatably mounted on the workbench, and is used to fix the workpiece to be measured, thereby driving the workpiece to be measured to rotate together; the measuring device body comprises a horizontal displacement probe, a horizontal probe sealing sleeve, a shell, an air pipe, a vertical displacement probe and a vertical probe sealing sleeve;

[0007] The shell is fixed on the vertical lifting mechanism, and the main body of the measuring device is located inside the workpiece to be measured during measurement; three horizontal probe sealing sleeves are evenly fixed in the shell along the same horizontal plane, and the three horizontal probe sealing sleeves are symmetrical about the vertical midline of the shell; a horizontal displacement probe is slidably installed in each of the three horizontal probe sealing sleeves, and the ends of the horizontal displacement probes are respectively connected to their respective horizontal probe sealing sleeves through springs; a vertical probe sealing sleeve is vertically fixed in the shell and is located on the vertical center axis of the shell; a vertical displacement probe is slidably installed in the vertical probe sealing sleeve, and the end of the vertical displacement probe is connected to the vertical probe sealing sleeve through a spring; the three horizontal probe sealing sleeves and one vertical probe sealing sleeve are connected to an external air pump through their respective air pipes, and the air pressure of the four probe sealing sleeves is the same; the horizontal displacement probe and the vertical displacement probe are connected to the host computer through their respective data lines.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] (1) The present invention measures the inner diameter data by means of a three-point inner diameter measuring device and solves the inner diameter using an elliptic equation, thereby realizing automated mechanical three-point inner diameter measurement, comprehensively considering various errors, and improving measurement efficiency and measurement accuracy.

[0010] (2) The present invention provides power for extending the probe by pneumatic means. There is no mechanical linkage between the probes of each displacement sensor, and the data of the workpiece to be measured can be measured separately, thereby ensuring the effective measurement of each probe. Compared with the existing one-point and two-point inner diameter measurement methods, the measurement efficiency is improved.

[0011] (3) The present invention realizes the solution of the inner diameter by the ellipse equation by adding a vertical displacement probe. Compared with the commonly used circle equation solution method, it eliminates the calculation error and takes into account multiple errors such as the axis tilt error, probe installation error and tilt error, thereby improving the measurement accuracy.

[0012] (4) The present invention measures the inner diameter by point measurement to obtain the inner diameter values ​​of multiple measurement positions of the workpiece to be measured. Compared with the commonly used continuous measurement method, the damage to the workpiece to be measured is reduced, and the corresponding measurement errors are avoided, thereby improving the measurement accuracy.

[0013] (5) The present invention obtains the inner diameter, roundness error and angle α by calculating and analyzing the measurement data. By monitoring the above results, it has the functions of measurement, analysis and alarm, realizes the monitoring of the operating status of the measuring device, avoids rework and re-inspection and even damage to parts due to untimely maintenance of the measuring device, provides a more reasonable dynamic maintenance cycle of the equipment, thereby reducing maintenance time, improving product quality and yield rate, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a three-dimensional schematic diagram of the measuring device body of the present invention;

[0015] Figure 2 It is a three-dimensional schematic diagram of the measuring device body with the shell removed according to the present invention;

[0016] Figure 3 It is a schematic diagram of the measuring device of the present invention when measuring;

[0017] Figure 4 It is a three-dimensional schematic diagram of the overall structure of the present invention;

[0018] Figure 5 A schematic diagram of a plane rectangular coordinate system established for the present invention;

[0019] Figure 6 It is the principle diagram of the measurement state of the present invention.

[0020] In the figure, there are a horizontal displacement probe 1, a horizontal probe sealing sleeve 2, a housing 3, a data cable 4, an air pipe 5, a vertical displacement probe 6, a rotating table 7, a piece to be measured 8, a suspension mechanism 9, a lifting module 10, a gantry frame 11, a workbench 12, and a vertical probe sealing sleeve 13. DETAILED DESCRIPTION

[0021] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention in detail and do not limit the protection scope of the claims of the present invention.

[0022] The present invention provides an inner diameter measuring device (hereinafter referred to as the device), characterized in that the device comprises a measuring device body, a vertical lifting mechanism, a rotating table 7 and a workbench 12; the rotating table 7 is rotatably mounted on the workbench 12, and is used to fix and mount a workpiece to be measured 8, thereby driving the workpiece to be measured 8 to rotate together; the measuring device body comprises a horizontal displacement probe 1, a horizontal probe sealing sleeve 2, a housing 3, a data line 4, an air pipe 5, a vertical displacement probe 6 and a vertical probe sealing sleeve 13;

[0023] The shell 3 is fixed on the vertical lifting mechanism, and the main body of the measuring device is located inside the workpiece 8 to be measured during measurement; three horizontal probe sealing sleeves 2 are evenly fixed in the shell 3 along the same horizontal plane, and the three horizontal probe sealing sleeves 2 are symmetrical about the vertical midline of the shell 3; a horizontal displacement probe 1 is slidably installed in each of the three horizontal probe sealing sleeves 2, and the ends of the horizontal displacement probes 1 are respectively connected to their respective horizontal probe sealing sleeves 2 through springs; a vertical probe sealing sleeve 13 is vertically fixed in the shell 3 and is located on the vertical center axis of the shell 3; a vertical displacement probe 6 is slidably installed in the vertical probe sealing sleeve 13, and the ends of the vertical displacement probe 6 are connected to the vertical probe sealing sleeve 13 through a spring; the three horizontal probe sealing sleeves 2 and one vertical probe sealing sleeve 13 are connected to an external air pump through their respective air pipes 5, and the air pressure of the four probe sealing sleeves is the same; the horizontal displacement probe 1 and the vertical displacement probe 6 are connected to the host computer through their respective data lines 4.

[0024] Preferably, the vertical lifting mechanism includes a suspension mechanism 9, a lifting module 10 and a gantry frame 11; the fixed end of the lifting module 10 is fixed to the workbench 12 through the gantry frame 11; the suspension mechanism 9 is fixed to the movable end of the lifting module 10, and the lifting module 10 drives the suspension mechanism 9 to perform vertical lifting in the vertical direction; the shell 3 is fixed on the suspension mechanism 9.

[0025] Preferably, the three horizontal displacement probes 1 are spaced at an angle of 120° from each other.

[0026] The present invention provides an inner diameter measuring method based on the inner diameter measuring device (hereinafter referred to as the method), characterized in that the method comprises the following steps:

[0027] Step 1, build the inner diameter measuring device; the device includes a measuring device body, a vertical lifting mechanism, a rotating table 7 and a workbench 12; the rotating table 7 is rotatably mounted on the workbench 12, and is used to fix the test piece 8, thereby driving the test piece 8 to rotate together; the measuring device body includes a horizontal displacement probe 1, a horizontal probe sealing sleeve 2, a housing 3, a data cable 4, an air pipe 5, a vertical displacement probe 6 and a vertical probe sealing sleeve 13;

[0028] The shell 3 is fixed on the vertical lifting mechanism, and the main body of the measuring device is located inside the workpiece 8 to be measured during measurement; three horizontal probe sealing sleeves 2 are evenly fixed in the shell 3 along the same horizontal plane, and the three horizontal probe sealing sleeves 2 are symmetrical about the vertical mid-perpendicular center of the shell 3; a horizontal displacement probe 1 is slidably installed in each of the three horizontal probe sealing sleeves 2, and the ends of the horizontal displacement probes 1 are respectively connected to their respective horizontal probe sealing sleeves 2 through springs; a vertical probe sealing sleeve 13 is vertically fixed in the shell 3 and is located on the vertical center axis of the shell 3; a vertical displacement probe 6 is slidably installed in the vertical probe sealing sleeve 13, and the ends of the vertical displacement probe 6 are connected to the vertical probe sealing sleeve 13 through a spring; the three horizontal probe sealing sleeves 2 and one vertical probe sealing sleeve 13 are connected to an external air pump through their respective air pipes 5, and the air pressure of the four probe sealing sleeves is the same; the horizontal displacement probe 1 and the vertical displacement probe 6 are connected to the host computer through their respective data lines 4;

[0029] Step 2: Displacement probe measurement data:

[0030] S2.1. Fix the test piece 8 on the rotating table 7; start the lifting module 10 to drive the measuring device body to move into the test piece 8;

[0031] S2.2, the external air pump is started, and the gas is passed into the horizontal probe sealing sleeve 2 and the vertical probe sealing sleeve 13 through the air pipe 5, and the horizontal displacement probe 1 is pushed out along the horizontal probe sealing sleeve 2 by air pressure, and the three horizontal displacement probes 1 all contact the inner wall of the workpiece 8 to be measured; the vertical displacement probe 6 is pushed out along the vertical probe sealing sleeve 13 by air pressure, and the vertical displacement probe 6 contacts the rotating table 7; then the extension length of the three horizontal displacement probes 1 and the one vertical displacement probe 6 is measured, and the data is transmitted to the host computer through the data line 4; after the measurement is completed, the air pump is turned off, and the horizontal displacement probe 1 and the vertical displacement probe 6 are recovered to the initial position under the action of the spring;

[0032] S2.3, the measuring device body does not move, the rotating table 7 rotates to drive the measured object 8 to rotate, and stops rotating after reaching the second measuring position; then repeat step S2.2 until the measurement of all measuring positions is completed;

[0033] Step 3: The host computer calculates the inner diameter values ​​of the test piece 8 at all the measurement positions according to the measurement data obtained in step 2;

[0034] Preferably, step 3 specifically includes:

[0035] S3.1. Take the intersection of the center axis of the object to be measured 8 and the plane where the central axis of the three horizontal displacement probes 1 are located as the coordinate origin, and the parallel direction of any one of the three horizontal displacement probes 1 as the x-axis to establish a plane rectangular coordinate system;

[0036] S3.2. Since there is an angle error between the central axis of the test piece 8 and the vertical center axis of the housing 3 (i.e., the tilt error between the axes), each measuring position on the test piece 8 is actually a point on an ellipse. Then, the inner diameter value of each measuring position on the test piece 8 is calculated by using the ellipse equation and taking into account the installation error and tilt error of the probe. The calculation formula is:

[0037]

[0038] In formula (1), r1, r2, and r3 are the distances from the intersection of the central axis of the three horizontal probe sealing sleeves 2 and the vertical central axis of the shell 3 to the inner wall of the test piece 8; β is the angle between the horizontal displacement probe 1 and the horizontal direction when the measuring device body is vertical, which represents the installation error and tilt error of the horizontal displacement probe 1, and is a constant after the device is installed; a is the distance from the vertical central axis of the shell 3 on the elliptical surface to the origin of the plane rectangular coordinate system constructed in step S3.1, a=L2*tanα; α is the angle between the central axis of the test piece 8 and the vertical central axis of the shell 3, and the calculation formula of the angle α is:

[0039] α=arccos[L3 / (L1cosγ+L2)] (2)

[0040] In formula (2), L1 is the distance from the intersection of the vertical center axis of the shell 3 and the plane where the center axes of the three horizontal displacement probes 1 are located to the rotating table 7; L2 is the vertical distance from the installation position of the measuring device body on the suspension mechanism 9 to the plane where the center axes of the three horizontal displacement probes 1 are located, which is a constant after the device is installed; L3 is the vertical distance from the installation position of the measuring device body on the suspension mechanism 9 to the rotating table 7; γ is the angle between the vertical displacement probe 6 and the vertical direction when the measuring device body is vertical, which represents the installation error and tilt error of the vertical displacement probe 6, and is a constant after the device is installed.

[0041] Step 4: Based on the inner diameter values ​​of the test piece 8 at each measuring position obtained in step 3, an average value of the inner diameter values ​​of the test piece 8 at all measuring positions is used as the final inner diameter value of the test piece 8.

[0042] The present invention also provides a method for equipment testing and product evaluation using the final inner diameter value of the test piece 8 obtained in step 4, which is characterized by comprising the following steps:

[0043] (1) The roundness error of the test piece 8 is obtained by subtracting the minimum inner diameter from the maximum inner diameter of the test piece 8 at all measuring positions;

[0044] (2) monitoring the roundness error and the angle α in real time through the host computer; if any one of the roundness error and the angle α exceeds its own safety value, reminding the maintenance personnel to maintain the inner diameter measuring device;

[0045] If the roundness error exceeds the roundness design error, re-measure; if it exceeds the roundness design error again, an alarm will be issued and the product will be temporarily recorded as a defective product.

[0046] Preferably, in step (2), the safety value of the roundness error is obtained by multiplying the roundness design error by the safety factor, the roundness design error is determined during product design, and the safety factor is learned from experience; the safety value of the angle α is also learned from experience.

[0047] Preferably, in step (2), after the product is temporarily recorded as defective, it is manually re-inspected by an engineer to determine the final evaluation result.

[0048] Preferably, in step (2), the monitoring system for real-time monitoring of the roundness error and the angle α by a host computer is developed using LabVIEW as the host computer software, and the host computer and the inner diameter measuring device are connected via Ethernet.

[0049] Any matters not described in the present invention are applicable to the prior art.

Claims

1. An inner diameter measuring device, It is characterized in that The device comprises a measuring device body, a vertical lifting mechanism, a rotating table (7) and a workbench (12); the rotating table (7) is rotatably mounted on the workbench (12) and is used to fix a workpiece to be measured (8), thereby driving the workpiece to be measured (8) to rotate together; the measuring device body comprises a horizontal displacement probe (1), a horizontal probe sealing sleeve (2), a housing (3), an air pipe (5), a vertical displacement probe (6) and a vertical probe sealing sleeve (13); The housing (3) is fixed on the vertical lifting mechanism, and the main body of the measuring device is located inside the workpiece (8) to be measured during measurement; three horizontal probe sealing sleeves (2) are evenly fixed in the housing (3) along the same horizontal plane, and the three horizontal probe sealing sleeves (2) are symmetrical about the vertical mid-perpendicular line of the housing (3); a horizontal displacement probe (1) is slidably mounted in each of the three horizontal probe sealing sleeves (2), and the ends of the horizontal displacement probes (1) are respectively connected to the respective horizontal probe sealing sleeves (2) via springs; a vertical probe sealing sleeve (13) is vertically fixed The invention is fixed in the housing (3) and is located on the vertical center axis of the housing (3); a vertical displacement probe (6) is slidably installed in the vertical probe sealing sleeve (13), and the end of the vertical displacement probe (6) is connected to the vertical probe sealing sleeve (13) through a spring; three horizontal probe sealing sleeves (2) and one vertical probe sealing sleeve (13) are connected to an external air pump through respective air pipes (5), and the air pressure of the four probe sealing sleeves is the same; the horizontal displacement probe (1) and the vertical displacement probe (6) are connected to a host computer through respective data lines (4).

2. The inner diameter measuring device according to claim 1, It is characterized in that The vertical lifting mechanism comprises a suspension mechanism (9), a lifting module (10) and a gantry frame (11); the fixed end of the lifting module (10) is fixed to a workbench (12) via the gantry frame (11); the suspension mechanism (9) is fixed to the movable end of the lifting module (10), and the lifting module (10) drives the suspension mechanism (9) to be lifted vertically in a vertical direction; and the housing (3) is fixed to the suspension mechanism (9).

3. The inner diameter measuring device according to claim 1, It is characterized in that The three horizontal displacement measuring heads (1) are spaced at an angle of 120° from each other.

4. A method for measuring inner diameter based on the inner diameter measuring device according to any one of claims 1 to 3, It is characterized in that The method comprises the following steps: Step 1, building the inner diameter measuring device; Step 2: Displacement probe measurement data: S2.

1. Fix the object to be tested (8) on the rotating table (7); start the vertical lifting mechanism to drive the measuring device body to move into the object to be tested (8); S2.2, the external air pump is started, and the gas is passed into the horizontal probe sealing sleeve (2) and the vertical probe sealing sleeve (13) through the air pipe (5), and the horizontal displacement probe (1) is pushed out along the horizontal probe sealing sleeve (2) by air pressure, and the three horizontal displacement probes (1) all contact the inner wall of the workpiece (8) to be measured; the vertical displacement probe (6) is pushed out along the vertical probe sealing sleeve (13) by air pressure, and the vertical displacement probe (6) contacts the rotating table (7); then the extension lengths of the three horizontal displacement probes (1) and one vertical displacement probe (6) are measured, and the data is transmitted to the host computer; after the measurement is completed, the air pump is turned off, and the horizontal displacement probe (1) and the vertical displacement probe (6) are recovered to the initial position under the action of the spring; S2.3, the measuring device body remains stationary, the rotating table (7) rotates to drive the measured object (8) to rotate, and stops rotating after reaching the second measuring position; then repeat step S2.2 until all measuring positions are measured; Step 3, the host computer calculates the inner diameter value of the test piece (8) at all measurement positions according to the measurement data obtained in step 2; Step 4: Based on the inner diameter values ​​of the test piece (8) at each measuring position obtained in step 3, the average value of the inner diameter values ​​of the test piece (8) at all measuring positions is used as the final inner diameter value of the test piece (8).

5. The inner diameter measuring method according to claim 4, It is characterized in that Step 3 specifically is: S3.

1. Establish a plane rectangular coordinate system with the intersection of the center axis of the object to be measured (8) and the plane where the central axis of the three horizontal displacement probes (1) are located as the coordinate origin and the parallel direction of any one of the three horizontal displacement probes (1) as the x-axis; S3.

2. Since there is an angle error between the central axis of the test piece (8) and the vertical center axis of the housing (3), each measuring position on the test piece (8) is actually a point on an ellipse. Then, the inner diameter value of each measuring position on the test piece (8) is calculated by using the ellipse equation and taking into account the installation error and tilt error of the probe. The calculation formula is: In formula (1), r 1 、r 2 、r 3 are the distances from the intersection of the center axis of the sealing sleeves (2) of the three horizontal probes and the vertical center axis of the shell (3) to the inner wall of the object to be measured (8); β is the angle between the horizontal displacement probe (1) and the horizontal direction when the main body of the measuring device is vertical, which represents the installation error and tilt error of the horizontal displacement probe (1) and is a constant after the device is installed; a is the distance from the vertical center axis of the shell (3) on the elliptical surface to the origin of the plane rectangular coordinate system constructed in step S3.1, a=L 2 *tanα; α is the angle between the central axis of the test piece (8) and the vertical center axis of the housing (3), which represents the tilt error between the axes. The calculation formula of the angle α is: α=arccos[L 3 / (THE 1 cosγ+L 2 )] (2) In formula (2), L 1 L is the distance from the intersection of the plane where the vertical center axis of the housing (3) and the center axes of the three horizontal displacement probes (1) are located to the rotating table (7); 2 It is the vertical distance from the installation position of the measuring device body on the vertical lifting mechanism to the plane where the central axis of the three horizontal displacement probes (1) are located, and is a fixed value after the device is installed; L 3 is the vertical distance from the installation position of the measuring device body on the vertical lifting mechanism to the rotating platform (7); γ is the angle between the vertical displacement probe (6) and the vertical direction when the measuring device body is vertical, indicating the installation error and tilt error of the vertical displacement probe (6), and is a fixed value after the device is installed.

6. A method for equipment testing and product evaluation using the final inner diameter value of the test piece obtained in claim 5, It is characterized in that The following steps are involved: (1) The roundness error of the test piece (8) is obtained by subtracting the minimum inner diameter from the maximum inner diameter of the test piece (8) at all measuring positions; (2) monitoring the roundness error and the angle α in real time through the host computer; if any one of the roundness error and the angle α exceeds its own safety value, reminding the maintenance personnel to maintain the inner diameter measuring device; If the roundness error exceeds the roundness design error, re-measure; If the roundness exceeds the design error again, an alarm will be issued and the product will be temporarily recorded as defective.

7. The method for equipment detection and product evaluation according to claim 6, It is characterized in that In step (2), the safety value of the roundness error is obtained by multiplying the roundness design error by the safety factor. The roundness design error is determined during product design, and the safety factor is learned from experience. The safety value of the angle α is also learned from experience.

8. The method for equipment detection and product evaluation according to claim 6, It is characterized in that In step (2), the product is temporarily recorded as defective and then manually re-inspected by engineers to determine the final evaluation result.

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