Method and device for automatically measuring inner taper hole

Abstract

The invention relates to an automatic measurement method and device for an inner taper hole, and relates to the technical field of measurement, and the device comprises a base, a supporting unit, an axial feeding unit, a size measurement unit, a positioning and clamping unit and a position detection unit. The supporting units are distributed and installed on the base in the circumferential direction, the axial feeding unit is installed on the supporting units, the size measuring unit and the positioning and clamping unit are installed on a spline shaft of the axial feeding unit, and the position detecting unit is installed on the supporting units. According to the invention, an integrated structural design is adopted, positioning and clamping of an inner taper hole part, section dimension measurement and an axial moving structure are integrated, the structural design is ingenious, the size is small, and the device can be used in various complex environments; the stepping motor is matched with the ball screw to achieve axial feeding of the size measuring unit, circumferential movement of the size measuring unit is limited through the spline shaft, and the size measuring device has the advantages of being high in movement precision, flexible in movement, compact in structure and the like.

Description

Technical Field

[0001] This invention belongs to the field of measurement, specifically relating to an automatic measurement method and apparatus for internal conical holes. Background Technology

[0002] Internal tapered hole parts are widely used in critical connections in the machining field, serving functions such as high-precision fitting, rapid positioning and installation, and bearing large loads. The dimensional accuracy of the internal tapered hole is crucial to ensuring the normal operation of equipment; therefore, accurate measurement of internal tapered holes of different sizes is essential in numerous machining and manufacturing processes. Currently, the measurement of internal tapered holes typically employs traditional measuring tools such as vernier calipers and micrometers for contact measurement. These tools have significant limitations in measuring complex parameters such as roundness, external angles, and internal angles of internal tapered holes, leading to large errors in the measurement results. Furthermore, for internal tapered hole parts made of special materials, such as high-temperature alloys or ceramics, traditional contact measuring instruments may damage the workpiece surface, affecting the surface quality of the product. Summary of the Invention

[0003] This invention provides an automatic measurement method and device for internal conical holes, which overcomes the shortcomings of the prior art and enables accurate measurement of important dimensional parameters such as roundness, external angle, and internal angle of internal conical holes without contact.

[0004] To solve the above technical problems, the present invention provides an automatic measuring device for internal conical holes, characterized in that it comprises:

[0005] Base (2);

[0006] The support units are circumferentially distributed and installed on the base (2);

[0007] An axial feed unit is mounted on the support unit;

[0008] A dimension measuring unit is installed at the end of the splined shaft (10) of the axial feed unit;

[0009] The positioning and clamping unit is installed on the inner tapered hole part (22) and is used to position the spline shaft (10).

[0010] A position detection unit is used to detect the axial position of the dimension measuring unit;

[0011] The axial feed unit drives the ball screw (9) via a stepper motor (1) to move the spline shaft (10) axially along the inner conical hole. The dimension measuring unit drives the laser sensor (16) to rotate via a rotary motor (15) to measure the inner conical hole.

[0012] The axial feed unit includes:

[0013] A stepper motor (1) is mounted on a base and connected to a ball screw (9) via a coupling (3);

[0014] The slider (7) is engaged with the ball screw (9);

[0015] One end of the spline shaft (10) is connected to the slider (7) through the shaft clamp (20), and the other end passes through the positioning clamping unit and is connected to the dimension measuring unit.

[0016] The dimension measuring unit includes:

[0017] The motor mounting bracket (14) is connected to the splined shaft (10);

[0018] A rotary motor (15) is mounted on the motor mounting bracket (14);

[0019] The probe holder (18) is connected to the output shaft of the rotary motor (15);

[0020] At least one laser sensor (16) is circumferentially mounted on the probe holder (18) via a sensor mounting plate (17).

[0021] The number of laser sensors (16) is three, which are evenly distributed around the perimeter.

[0022] The positioning and clamping unit includes:

[0023] The positioning end cap (12) is used to cooperate with the inner hole of the inner tapered hole part (22) to achieve radial positioning;

[0024] At least one clamping mechanism clamps the part by means of a disc nut (13).

[0025] The clamping mechanism consists of three parts, which are evenly distributed around the circumference.

[0026] The position detection unit includes:

[0027] A grating ruler (8) is mounted on the support unit;

[0028] The grating ruler reading head (6) is connected to the slider (7) via the connecting block (5).

[0029] The positioning and clamping unit is equipped with a splined shaft flange, which mates with the splined shaft.

[0030] An automatic measurement method for an internal conical hole, characterized by comprising the following steps:

[0031] The inner tapered hole part (22) is docked with and clamped to the positioning and clamping unit, and the position detection unit is located in the inner tapered hole of the inner tapered hole part (22);

[0032] The stepper motor (1) drives the spline shaft (10) to move the dimension measuring unit axially to the section to be measured;

[0033] A rotary motor (15) drives a laser sensor (16) to rotate, measuring the cross-sectional dimensions of the inner conical hole;

[0034] Repeat the above steps to complete the measurement of multiple cross sections;

[0035] Calculate the inner diameter, roundness, external angle, and internal angle of the inner conical hole based on the measurement data.

[0036] The inner diameter and roundness of the inner conical hole section are calculated by fitting using a numerical algorithm.

[0037] The formulas for calculating the positive and negative angles are as follows:

[0038] α = π + arctan[(D1 - D2) / L]

[0039] β=π-arctan[(D1-D2) / L]

[0040] Where D1 and D2 are the inner diameters of the two sections, and L is the axial distance between the two sections.

[0041] Beneficial effects:

[0042] 1. This invention adopts an integrated structural design, which integrates the positioning and clamping of the inner tapered hole part, the measurement of cross-sectional dimensions, and the axial movement structure. The structure is ingeniously designed and has a small size, making it suitable for use in various complex environments.

[0043] 2. This invention uses a stepper motor in conjunction with a ball screw to achieve the axial feed of the dimension measuring unit, and restricts the circumferential movement of the dimension measuring unit through a spline shaft, which has the characteristics of high motion accuracy, flexible movement, and compact structure.

[0044] 3. This invention uses a rotary motor to drive the laser sensor to rotate, enabling multiple measurements of the same cross section, eliminating data errors caused by chatter and cantilever, and ensuring that the device has higher measurement accuracy;

[0045] 4. This invention solves the problems of low measurement accuracy, low efficiency, and damage to the surface of internal conical hole parts caused by traditional contact measurement. Attached Figure Description

[0046] Figure 1 An isometric view of the device of the present invention in its installed state.

[0047] Figure 2 Axial cross-sectional view measured by the device of the present invention.

[0048] Figure 3 This is a schematic diagram of the working state of the device of the present invention.

[0049] Figure 4 Schematic diagram of the measurement process for internal tapered hole parts

[0050] In the diagram: 1. Stepper motor, 2. Base, 3. Coupling, 4. Lead screw fixing seat, 5. Connecting block, 6. Grating ruler reading head, 7. Slider, 8. Grating ruler, 9. Ball screw, 10. Splined shaft, 11. Splined shaft flange, 12. Positioning end cover, 13. Disc nut, 14. Motor mounting bracket, 15. Rotary motor, 16. Laser sensor, 17. Sensor mounting plate, 18. Probe holder, 19. Aluminum profile, 20. Shaft clamp, 21. Probe protective cover, 22. Inner tapered hole part. Detailed Implementation

[0051] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below.

[0052] The present invention proposes an automatic measuring device for an internal conical hole, comprising a base 2, a support unit, an axial feed unit, a dimension measuring unit, a positioning and clamping unit, and a position detection unit. The support unit is circumferentially distributed and installed on the base 2. The axial feed unit is installed on the support unit. The dimension measuring unit and the positioning and clamping unit are installed on the splined shaft of the axial feed unit. The position detection unit is installed on the support unit. The stepper motor 1 of the axial feed unit drives the ball screw 9 to move the splined shaft 10 along the axial direction of the internal conical hole. At the same time, the end of the splined shaft 10 drives the dimension measuring unit to move along the axis of the internal conical hole. The dimension measuring unit drives the laser sensor 16 to rotate through the rotary motor 15. The position detection unit records and feeds back the position of the dimension measuring unit in real time.

[0053] The base 2 is a disc-shaped structure with mounting holes for the support unit machined around its circumference; a motor mounting hole and a positioning hole for fixing the stepper motor 1 of the axial feed unit are machined at the eccentric position of the base 2.

[0054] The support unit is fixed on the base, and the other end is connected to the positioning and clamping unit;

[0055] The axial feed unit includes a stepper motor 1, a coupling 3, a ball screw 9, a screw fixing seat 4, a slider 7, a shaft clamp 20, a splined shaft 10, and a splined shaft flange 11.

[0056] The stepper motor 1 is fixed on the base 2 and connected to the ball screw 9 through the coupling 3; the ball screw 9 is mounted on the screw fixing seat 4 and is driven by the stepper motor 1 to move the slider 7 on the ball screw 9.

[0057] The left end of the spline shaft 10 is connected to the slider 7 via the shaft clamp 20 and moves with the slider 7, while the right end is connected to the dimension measuring unit; the spline shaft flange 11 is connected to the positioning and clamping unit and cooperates with the spline shaft 10.

[0058] The dimensional measurement unit includes a motor mounting bracket 14, a rotary motor 15, a probe holder 18, a sensor mounting plate 17, a laser sensor 16, and a probe protective cover 21. The left end of the motor mounting bracket 14 is fixedly connected to the spline shaft 10, and the right end is connected to the rotary motor 15. The rotary motor 15 is connected to the probe holder 18. Three laser sensors 16 are circumferentially fixed on the probe holder 18 through the sensor mounting plate. The rotary motor 15 drives the probe holder 18 to move the laser sensors 16 to measure the dimensions of the inner tapered hole part 22. The probe protective cover 21 is fixed on the probe holder 18 to protect the laser sensors 16.

[0059] The positioning and clamping unit includes a positioning end cover 12 and three clamping mechanisms. The positioning end cover 12 is connected to the splined shaft flange 11 and is used to position the inner hole of the inner tapered hole part 22. The three clamping mechanisms are evenly distributed on the edge of the positioning end cover 12, and have wire grooves at corresponding positions. The inner tapered hole part 22 is fixed to the positioning and clamping unit by the disc nut 13.

[0060] The position detection unit includes a connecting block 5, a grating ruler reading head 6, and a grating ruler 8; the connecting block 5 connects the slider 7 and the grating ruler reading head 6; the grating ruler 8 is mounted on the aluminum profile 19 of the support unit.

[0061] An automatic measurement method for internal conical holes includes the following steps:

[0062] A. Connect the inner conical hole part 22 with the inner conical hole automatic measuring device. The radial positioning of the part is achieved by the positioning end cap 12 of the positioning clamping unit cooperating with the inner hole of the inner conical hole part 22. The end face of the positioning end cap 12 contacts the end face of the inner conical hole part to ensure the axial positioning of the entire device and the inner conical hole part 22.

[0063] B. Tighten the three clamping disc nuts 13 to clamp the inner conical hole part 22 by deforming the outer edge of the positioning clamping unit.

[0064] C. When measuring the dimensions of the inner tapered hole part 22, the stepper motor 1 drives the ball screw 9 to rotate. The ball screw 9 is connected to the spline shaft 10 through the slider 7 and the shaft clamp 20, driving the spline shaft 10 to move along the axis of the inner tapered hole. The grating ruler 8 records the axial position of the spline shaft 10. The rotary motor 15 inside the dimension measurement unit drives the laser sensor 16 to rotate to measure the roundness, external angle, and internal angle parameters of the inner tapered hole. The specific steps are as follows:

[0065] C1. The ball screw 9 drives the spline shaft 10 to move, and the spline shaft 10 drives the dimensional measuring unit to the measured section position of the inner conical hole part 22. The rotary motor 15 drives the probe holder 18 to rotate. Three laser sensors 16 measure the dimensions of the inner conical hole, record multiple sets of dimensional data, and transmit them to the computer through optical fiber. Numerical algorithms are used for fitting, and the center x0, y0 and radius R of the circle that best fits these data points are found by minimizing the sum of squares Q using the following formula. Then the diameter D = 2R, and the roundness is the distance d from each data point to the center of the fitted circle. i The difference between the extreme values, where This yields the outer diameter and roundness of the inner conical hole:

[0066]

[0067] Where n is the number of measurement points, that is, the number of sets of dimensional data obtained by the three laser sensors from the cross section of the inner conical hole to be measured;

[0068] X i ,Y i The coordinates of the i-th measurement point are obtained by processing the data measured by the laser sensor and transmitted to the computer.

[0069] x0 and y0 are unknown parameters that need to be solved by minimizing Q, representing the position of the center of the inner cone hole section;

[0070] a, b, and c are intermediate parameters introduced to simplify calculations;

[0071] C2. After the measurement of the section to be measured is completed, the stepper motor 1 drives the spline shaft 10 to move the dimension measurement unit to the next measurement section, and repeat the measurement in step C1. Repeat steps C1 and C2 for all sections of the inner tapered hole until all sections are measured.

[0072] C3. Using the inner diameters D1 and D2 of different sections of the inner conical hole obtained from measurements and data fitting, and the distance L between the two sections obtained by the grating ruler, calculate the positive and negative angles of the inner conical hole using the following formula:

[0073] α = π + arctan[(D1 - D2) / L]

[0074] β=π-arctan[(D1-D2) / L].

[0075] This invention solves a long-standing technical problem by combining laser measurement, ball screw, and grating ruler in a specific way to solve the problem of automated measurement of the special structure of the inner conical hole, and to achieve accurate measurement of the inside and outside corners. This combination produces a synergistic effect of "1+1>2".

[0076] Meanwhile, this invention cleverly combines "multiple laser sensors evenly distributed around the circumference" with "rotation measurement," which not only increases the amount of data and reliability of a single sampling through multiple sensors, but also further eliminates sensor-related and installation errors through rotation, thus greatly improving measurement accuracy.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An automatic measuring device for an internal conical hole, characterized in that, include: Base (2); The support units are circumferentially distributed and installed on the base (2); An axial feed unit is mounted on the support unit; A dimension measuring unit is installed at the end of the splined shaft (10) of the axial feed unit; The positioning and clamping unit is installed on the inner tapered hole part (22) and is used to position the spline shaft (10). A position detection unit is used to detect the axial position of the dimension measuring unit; The axial feed unit drives the ball screw (9) via a stepper motor (1) to move the spline shaft (10) axially along the inner conical hole. The dimension measuring unit drives the laser sensor (16) to rotate via a rotary motor (15) to measure the inner conical hole.

2. The automatic measuring device for internal conical holes according to claim 1, characterized in that, The axial feed unit includes: A stepper motor (1) is mounted on a base and connected to a ball screw (9) via a coupling (3); The slider (7) is engaged with the ball screw (9); One end of the spline shaft (10) is connected to the slider (7) through the shaft clamp (20), and the other end passes through the positioning clamping unit and is connected to the dimension measuring unit.

3. The automatic measuring device for internal conical holes according to claim 2, characterized in that, The dimension measuring unit includes: The motor mounting bracket (14) is connected to the splined shaft (10); A rotary motor (15) is mounted on the motor mounting bracket (14); The probe holder (18) is connected to the output shaft of the rotary motor (15); At least one laser sensor (16) is circumferentially mounted on the probe holder (18) via a sensor mounting plate (17).

4. The automatic measuring device for internal conical holes according to claim 3, characterized in that, The number of laser sensors (16) is three, which are evenly distributed around the perimeter.

5. The automatic measuring device for internal conical holes according to claim 1, characterized in that, The positioning and clamping unit includes: The positioning end cap (12) is used to cooperate with the inner hole of the inner tapered hole part (22) to achieve radial positioning; At least one clamping mechanism clamps the part by means of a disc nut (13).

6. The automatic measuring device for internal conical holes according to claim 5, characterized in that, The clamping mechanism consists of three parts, which are evenly distributed around the circumference.

7. The automatic measuring device for internal conical holes according to claim 1, characterized in that, The position detection unit includes: A grating ruler (8) is mounted on the support unit; The grating ruler reading head (6) is connected to the slider (7) via the connecting block (5).

8. The automatic measuring device for internal conical holes according to claim 1, characterized in that, The positioning and clamping unit is equipped with a splined shaft flange, which mates with the splined shaft.

9. An automatic measurement method for an internal conical hole, employing the apparatus as described in any one of claims 1-8, characterized in that, Includes the following steps: The inner tapered hole part (22) is docked with and clamped to the positioning and clamping unit, and the position detection unit is located in the inner tapered hole of the inner tapered hole part (22); The stepper motor (1) drives the spline shaft (10) to move the dimension measuring unit axially to the section to be measured; A rotary motor (15) drives a laser sensor (16) to rotate, measuring the cross-sectional dimensions of the inner conical hole; Repeat the above steps to complete the measurement of multiple cross sections; Calculate the inner diameter, roundness, external angle, and internal angle of the inner conical hole based on the measurement data.

10. The automatic measurement method for internal conical holes according to claim 9, characterized in that, The inner diameter and roundness of the inner conical hole section are calculated by fitting using a numerical algorithm. The formulas for calculating the positive and negative angles are as follows: α = π + arctan[(D1 - D2) / L] β=π-arctan[(D1-D2) / L] Where D1 and D2 are the inner diameters of the two sections, and L is the axial distance between the two sections.

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