Cylinder diameter measuring method

Abstract

The invention relates to the technical field of size measurement, in particular to a cylinder diameter measuring method. The cylinder diameter measuring method comprises the following steps: enabling a distance sensor to move around a cylinder around a set rotating center, taking the distance between the distance sensor and the rotating center as a set value R, representing the rotating angle of the distance sensor relative to an initial position in the circular motion process by P, representing the distance between the distance sensor and a corresponding measuring point on the peripheral surface of the cylinder by L, and calculating the diameter of the cylinder; the method comprises the following steps: acquiring L values corresponding to a plurality of angles P by using a distance sensor, establishing a coordinate system by taking a rotation center as an original point, acquiring coordinates of a plurality of measuring points, fitting the radius of a section circle where each measuring point of a cylinder is located through a least square method, and taking two times of the radius as the diameter of the cylinder. According to the measurement method, large errors caused by manual misoperation can be avoided, and the measurement precision can be controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of dimension measurement, and in particular to a method for measuring the diameter of a cylinder. Background Art

[0002] Rolling elements in bearings are typically manufactured from long cylindrical bar stock. The weight of the required segments is calculated using the consumption quotas required for rolling element production, and a circular saw is used to cut the bar stock into short segments. During the initial process, the weight of the segments required for this cut is determined, and the bar stock diameter is measured. A conveyor is first used to move the bar stock, placed on its support, to the pre-cutting position. The end of the bar stock is positioned using a baffle. Before cutting, the length of the segment to be cut by the circular saw is calculated based on the measured bar stock diameter and the set required segment weight. The conveyor then feeds the bar stock into the circular saw for cutting, one segment at a time, according to the calculated length. The weight of the segment cut is considered the set required segment weight.

[0003] At present, the commonly used detection tools for measuring the diameter of cylindrical bars are calipers or diameter micrometers. However, the diameter measured by this measurement method depends on the proficiency of the operator and is prone to the risk of deviation, resulting in inaccurate diameter measurement. Moreover, in actual processing, the consistency of the diameter, cylindricity, taper, etc. of bars of the same specification also varies, affecting the weight of the actual cut material segment. The actual weight of the material segment is likely to deviate significantly from the set standard weight, affecting subsequent processing and even causing the material segment to be scrapped. Summary of the Invention

[0004] The object of the present invention is to provide a method for measuring the diameter of a cylinder to solve the problem that the current manual measurement method using a caliper tool is prone to large deviations.

[0005] The technical solution of the cylindrical diameter measuring method of the present invention is: A method for measuring the diameter of a cylinder includes: causing a distance sensor to move around the cylinder with a set rotation center, using the distance between the distance sensor and the rotation center as a set value R, representing the angle rotated by the distance sensor relative to a starting position during the circular motion as P, representing the distance between the distance sensor and a corresponding measuring point on the outer peripheral surface of the cylinder as L, wherein the measuring point, the distance sensor, and the rotation center are collinear, using the distance sensor to obtain L values corresponding to multiple angles P, establishing a coordinate system with the rotation center as the origin, wherein the X-axis direction of the coordinate system is the direction of a line connecting the distance sensor at the starting position and the rotation center, the Y-axis is perpendicular to the X-axis and is located at the cross section of the cylinder where each measuring point is located, the abscissa X=(RL)cosP, and the ordinate Y=(RL)sinP of the measuring point, obtaining the coordinates of multiple measuring points, then fitting the radius of the cross-sectional circle where each measuring point is located on the cylinder using the least squares method, and taking twice the radius as the diameter of the cylinder.

[0006] Beneficial effect: The present invention pioneers a method for accurately measuring the diameter of a cylinder. The distance sensor moves along a set circle. The center of the trajectory circle of the distance sensor is the rotation center, and the radius is the set value of the distance between the distance sensor and the rotation center. In the process of the distance sensor moving around the cylinder, the distance sensor is used to measure the distance between multiple distance sensors and corresponding measuring points on the outer peripheral surface of the cylinder. Each measuring point corresponds to a distance, and each measuring point corresponds to an angle. A plane rectangular coordinate system is established using the starting position of the distance sensor and the rotation center. Each angle of the distance sensor has a corresponding distance value. The coordinates of the measuring point can be obtained using the relationship between the angle and the distance. Using a set of multiple measuring point coordinates, the radius of the cross-section circle where each measuring point of the cylinder is located is fitted by the least squares method, and then the diameter of the cylinder is obtained. This measurement method can avoid large errors caused by improper human operation, is conducive to controlling measurement accuracy, and achieves accurate measurement.

[0007] Furthermore, the distance sensor moves around the cylinder once, and each quadrant of the coordinate system has corresponding measuring point coordinates.

[0008] Furthermore, the interval angles of the various measuring points relative to the rotation center are the same.

[0009] Furthermore, the distance sensor measures the L value once every time it rotates by an angle α, and the number of measurements is k; P=nα, n=1, 2, 3, ..., k; each P value corresponds to an L value.

[0010] Furthermore, the cylindrical bar material to be segmented is measured, and the diameter of each segment is measured before cutting.

[0011] Furthermore, the distance sensor is fixedly mounted on the outer ring of the bearing, the outer ring of the bearing is connected to the motor so as to drive the outer ring of the bearing to rotate through the motor, and the inner ring of the bearing is fixedly mounted on the mounting ring of the base, and the space inside the mounting ring is for the cylinder to pass through.

[0012] Furthermore, the outer ring of the bearing is a gear structure, and a driving gear meshing with the outer ring of the bearing is installed on the output shaft of the motor to drive the outer ring of the bearing to rotate.

[0013] Furthermore, the distance sensor is positioned and mounted on the outer ring of the bearing and faces the center of the bearing.

[0014] Furthermore, the bar material to be segmented is measured. The section of the bar material to be cut is a cylinder. The bar material to be segmented is transported by a conveying device. The distance sensor measures the distance between it and the section of the bar material to be cut on the bar material support seat of the conveying device to realize the diameter measurement of the section to be cut.

[0015] Furthermore, the supporting seat of the conveying device has a front support and a rear support spaced apart along the bar conveying direction, and the space between the front support and the rear support forms a space for the distance sensor to rotate around the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of a measuring device used in a method for measuring the diameter of a cylinder according to an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the measurement components in; Figure 3 for Figure 2 Schematic diagram of the base in; Figure 4 for Figure 2 Schematic diagram of the bearing in; Figure 5 Schematic diagram of the cylinder diameter measurement principle of the present invention.

[0017] In the figure: 100, cylinder; 1, support seat; 2, base; 21, mounting ring; 3, motor; 4, driving gear; 5, transmission bearing; 51, outer ring; 52, inner ring; 53, fixing hole; 6, distance sensor. DETAILED DESCRIPTION

[0018] The basic concept of the cylinder diameter measurement method of the present invention is to use a distance sensor that moves around the cylinder to measure the distance from it to the corresponding measuring point on the cylinder, and determine the coordinates of the measuring point in combination with the rotation angle. Using a set of multiple measuring point coordinates, the radius of the cross-sectional circle where each measuring point of the cylinder is located is fitted by the least squares method, and then the cylinder diameter is obtained, which is conducive to controlling the measurement accuracy and achieving accurate measurement.

[0019] The present invention is described in detail below with reference to the embodiments.

[0020] Embodiment of the method for measuring the diameter of a cylinder of the present invention: The cylindrical diameter measurement method in this embodiment is used to measure bar stock. The bar stock is then cut into segments, which are used to manufacture rolling elements in bearing products. Each segment has a set weight. The diameter of the corresponding segment to be cut is measured, and the length of the segment to be cut by a circular saw is calculated based on the measured segment diameter and the set required segment weight. Before cutting, a conveyor feeds the bar stock into the circular saw in sections of the calculated length for cutting. The weight of the cut segments is considered the set required segment weight.

[0021] In order to ensure that the weight of the cut material section meets the requirements, its diameter measurement should be accurate. The cylinder diameter measurement method in this embodiment can achieve accurate measurement. For ease of understanding, the cylinder diameter measurement device used to implement the cylinder diameter measurement method is first introduced. Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the cylindrical diameter measuring device includes a conveying mechanism and a measuring assembly. The conveying mechanism is used to move the bar material, namely the cylinder 100. The conveying mechanism includes a support seat 1 for supporting the cylinder 100. The cylinder 100 is placed in the V-shaped groove of the support seat 1 to position and guide the bar material. The conveying mechanism also includes a pushing device that pushes the bar material along the support seat 1 to drive the bar material to the corresponding cutting position. The principle of bar material conveyance is well known and will not be described in detail here. The detection assembly includes a base 2, a drive mechanism, a distance sensor 6, an angle sensor, and a host computer. The host computer includes a processor and a memory, and the host computer is equipped with a program for implementing the cylindrical diameter measurement method.

[0022] Distance sensor 6 has a set center of rotation. A drive mechanism, comprising a transmission bearing 5, a motor 3, and a driving gear 4, is used to drive distance sensor 6 around cylinder 100. An angle sensor measures the rotation angle of distance sensor 6. Distance sensor 6 is oriented toward the center of rotation, and the distance between distance sensor 6 and the center of rotation is a set value. Motor 3 is a servo motor equipped with an encoder, which forms the angle sensor. Distance sensor 6, angle sensor, and motor 3 are connected to the host computer signal to control the corresponding actuators.

[0023] Combine Figure 5 The method for measuring the diameter of a cylinder includes: causing the distance sensor 6 to move around the cylinder 100 with a set rotation center, setting the distance between the distance sensor 6 and the rotation center as a set value R, denoting the angle rotated by the distance sensor 6 relative to the starting position during the circular motion by P, denoting the distance between the distance sensor 6 and the corresponding measuring point A on the outer circumference of the cylinder 100 by L, wherein the measuring point A, the distance sensor 6, and the rotation center are collinear, obtaining L values corresponding to multiple angles P using the distance sensor 6, establishing a coordinate system with the rotation center as the origin, wherein the X-axis direction of the coordinate system is the direction of the line connecting the distance sensor 6 at the starting position and the rotation center, the Y-axis is perpendicular to the X-axis and is located at the cross section of the cylinder 100 where each measuring point A is located, the abscissa X=(RL)cosP, and the ordinate Y=(RL)sinP of the measuring point A, obtaining the coordinates of multiple measuring points, then fitting the radius of the cross section circle where each measuring point of the cylinder 100 is located by the least squares method, and taking twice the radius as the diameter of the cylinder 100.

[0024] The distance sensor 6 moves along a set circle. The center of the trajectory circle S of the distance sensor 6 is the rotation center, and the radius is the set distance R between the distance sensor 6 and the rotation center. As the distance sensor 6 moves around the cylinder 100, the distance sensor 6 measures the distances between multiple corresponding measuring points A on the outer circumference of the cylinder 100. Each measuring point A corresponds to a distance L, and each measuring point A corresponds to an angle P. A plane rectangular coordinate system is established using the starting position of the distance sensor 6 and the rotation center. Each angle P of the distance sensor 6 has a corresponding distance L, and each angle corresponds to a measuring point. The difference between R and L is the distance M from the measuring point A to the rotation center. The relationship between angle P and distance L can be used to determine the coordinates of the measuring point A. Using the coordinates of the multiple measuring points, the radius of the cross-section circle of the cylinder 100 at each measuring point is fitted using the least squares method, thereby determining the diameter of the cylinder 100. This measurement method can avoid large errors caused by improper operation, facilitates control of measurement accuracy, and achieves precise measurement.

[0025] During measurement, the distance sensor 6 is moved around the cylinder 100 for one full revolution, with each measuring point distributed at different locations along the same circumference. Each quadrant of the coordinate system has corresponding measuring point coordinates. The angles between each measuring point and the center of rotation are the same, and the angles between each measuring point and the line connecting the measuring point and the center of rotation are the same. The measuring points cover the entire circumference as much as possible, which facilitates the accuracy of the calculation results. In other embodiments, the distance sensor can be moved for less than one revolution, such as half a revolution. When there are a sufficient number of measuring point coordinates, the accuracy of the calculation results can be guaranteed. In other embodiments, the angles between each measuring point and the line connecting the measuring point and the center of rotation can also vary; it is sufficient to record the angle P and distance L corresponding to the measuring point.

[0026] Distance sensor 6 measures L once every rotation angle α, with a number of measurements k, where P = nα, n = 1, 2, 3, ..., k; each P value corresponds to an L value. Distance sensor 6 measures once every angle α, facilitating control. In other embodiments, the distance sensor can be configured to continuously measure during rotation, with a certain number of measurement points selected from all measured data for calculation.

[0027] In this embodiment, the bar stock to be segmented is measured, and the diameter of each segment is measured before cutting to determine the length of the segment to be cut and ensure that the weight of the segment meets the production requirements of the bearing rolling elements. In other embodiments, the diameter measurement of other cylindrical workpieces or products can also be used.

[0028] Regarding the mounting structure of the detection assembly, the base 2 is provided with a mounting ring 21 through which the cylinder 100 passes. The inner ring 52 of the transmission bearing 5 is fixedly mounted on the mounting ring 21. The outer ring 51 of the transmission bearing 5 is in driving connection with the motor 3, which drives the outer ring 51 to rotate. The distance sensor 6 is fixedly mounted on the outer ring 51. The transmission bearing 5 is the bearing of the drive mechanism. The outer ring 51 of the bearing is a gear structure, and the output shaft of the motor 3 is mounted with a driving gear 4 that meshes with the outer ring 51 of the bearing. The support base 1 includes a front support and a rear support spaced apart along the direction of bar material transport. The gap between the front and rear supports forms a space for the distance sensor 6 to rotate one revolution around the cylinder 100. The base 2 and motor 3 are mounted in the gap between the front and rear supports. The gap between the V-grooves on the front and rear supports is suitable for accommodating the transmission bearing 5 and the mounting ring 21. The transmission bearing 5 and the mounting ring 21 are coaxial. The center hole of the mounting ring 21 covers the V-grooves of the support base 1, allowing the bar material in the supporting groove to pass through the mounting ring 21 and span across the front and rear supports. The distance sensor 6 can rotate one revolution to measure the portion of the bar material suspended between the front and rear supports. In other embodiments, a rotating ring can also be provided, which is rotatably mounted on the mounting ring via a bearing, and the distance sensor is fixed to the rotating ring.

[0029] The outer ring 51 of the bearing is provided with two fixing holes 53, which are used to securely mount a distance sensor 6. These holes are positioned so that, once secured, the sensor 6's probe faces the center of rotation, which is also the center of the bearing. Distance sensor 6 measures the distance between itself and the section of bar stock to be cut on the support 1, enabling the cylindrical diameter measuring device to measure the diameter of the section.

[0030] In this embodiment, the angle is recorded by the encoder of the servo motor. In other embodiments, the rotation angle of the outer ring of the bearing can also be directly measured. The base 2 is an L-shaped structure, including a vertical plate and a bottom plate, and a reinforcing rib is provided between the vertical plate and the bottom plate. A mounting ring 21 is provided on the top of the vertical plate, and a circular step is provided on the outer wall of the mounting ring 21. The transmission bearing 5 can be installed and fixed on the step. The transmission bearing 5 is a cylindrical roller bearing with an outer gear ring, which is the outer ring 51. The end face of the outer ring gear is provided with a fixing hole 53 for fixing the distance sensor 6. The center line of the two fixing holes 53 passes through the center of the bearing. Driven by the driving gear 4, the outer ring gear can be accurately rotated and positioned.

[0031] Before measurement, the bar is conveyed by the conveyor. When passing through the detection assembly, the conveyor is paused and the diameter of the bar's current cross-sectional circle is measured. The current cross-sectional circle is located on the portion of the bar suspended between the front and rear supports and corresponds to distance sensor 6. Trigonometric calculations are used to obtain the coordinate points of the bar's cross-sectional outer circle in the coordinate system. The radius of the measured bar's cross-sectional circle is then fitted using the least squares method to obtain the bar's diameter.

[0032] Motor 3 is a high-precision motor, and driving gear 4 is a high-precision gear. Component manufacturing and processing accuracy are guaranteed, as is the installation accuracy of distance sensor 6, which maintains its probe perpendicular to the bearing axis. Motor 3 controls precise angular rotation, driving driving gear 4 for high-precision angular rotation. This in turn drives the outer ring gear on which distance sensor 6 is mounted, ensuring high-precision angular positioning of the distance sensor during measurement and ensuring accurate measurement results.

[0033] As for the distance R between the distance sensor 6 and the center of rotation, the detection component can be calibrated in advance. Using a standard cylinder with a known diameter, a three-coordinate measuring instrument can be used to make the transmission bearing 5 coaxial with the standard cylinder. The standard cylinder is inserted into the mounting ring 21. The distance sensor 6 measures the distance between its probe and the corresponding point on the standard cylinder. The sum of this distance value and the known diameter value of the standard cylinder is the distance R between the distance sensor 6 and the center of rotation. After the position calibration of the distance sensor 6 is completed, the detection component can be installed on the bar conveyor line.

[0034] During measurement, the bar to be measured is first placed in the V-groove of the conveyor. The bar is then conveyed to the position before cutting. The end face of the bar is positioned by a baffle. The bar passes through the detection assembly and the conveyor is paused. The outer ring 51 drives the distance sensor 6 to rotate counterclockwise. The detection direction of the distance sensor 6 always points to the rotation center, which is also the center of the outer ring 51. The distance sensor 6 performs a rotational scanning measurement along a trajectory circle S with a radius R. The starting position of the distance sensor 6 is 0°. Every time the distance sensor 6 rotates by an angle α, the distance sensor 6 measures the distance to the outer circle of the cross section of the cylinder 100. The current distance L from the measuring point A on the outer surface of the cylinder 100 to the distance sensor 6 can be obtained. α can be any angle value. The number of measurements of the same cross section of the cylinder 100 is k, where k = (360° / α). Then, a data set of distance L (L1, L2, ..., Ln, L k ), n=1, 2, ..., k. In this embodiment, α is set to 10°, then k is 36, and 36 L values are obtained. When measuring the 36th time, the distance sensor 6 rotates 360° and returns to the starting point; Establish a plane rectangular coordinate system. The angle between the line connecting the measuring point A of the distance sensor on the measured section and the rotation center and the positive direction of the X axis is P. The X axis, Y axis, trajectory circle S, and the cross-section circle where the measuring point A is located are located in the same plane. The coordinates of each point A can be obtained by trigonometric calculation. The specific values are the horizontal coordinate x n =(R–Ln)cos(nα); ordinate y n=(R–Ln)sin(nα);n=1,2,…,k,that is, there are k coordinate points. According to each coordinate point, the radius of the cross-section circle of the measured bar can be fitted by the least squares method, and then the bar diameter, that is, the diameter of the cylinder, can be obtained.

[0035] The above data calculation and processing process can be performed through the mathematical calculation model imported into the host, the distance sensor and angle sensor provide input, and the host outputs the calculation results and displays them on the corresponding screen.

[0036] It can realize continuous and accurate measurement of the diameter of the cylinder and perform real-time detection of the diameter of the bar, which is conducive to accurately controlling the length of the section to be cut, and then accurately controlling the weight of the cut section of the bar, reducing the waste of raw materials and the processing time of subsequent processes, and achieving the goal of reducing costs and increasing efficiency.

[0037] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments without inventive effort, or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for measuring the diameter of a cylinder, characterized in that: The distance sensor is made to move around the cylinder with a set rotation center. The distance between the distance sensor and the rotation center is set as the set value R. P represents the angle rotated by the distance sensor relative to the starting position during the circular motion. L represents the distance between the distance sensor and the corresponding measuring point on the outer circumference of the cylinder. The measuring point, the distance sensor and the rotation center are collinear. The distance sensor is used to obtain the L values corresponding to multiple angles P. A coordinate system is established with the rotation center as the origin. The X-axis direction of the coordinate system is the direction of the line connecting the distance sensor at the starting position and the rotation center. The Y-axis is perpendicular to the X-axis and is located at the cross section of the cylinder where each measuring point is located. The horizontal coordinate X=(RL)cosP and the vertical coordinate Y=(RL)sinP of the measuring point are obtained. The coordinates of multiple measuring points are then fitted using the least squares method to obtain the radius of the cross-sectional circle where each measuring point of the cylinder is located. Double the radius is used as the diameter of the cylinder.

2. The method for measuring the diameter of a cylinder according to claim 1, wherein: The distance sensor moves around the cylinder once, and each quadrant of the coordinate system has corresponding measuring point coordinates.

3. The method for measuring the diameter of a cylinder according to claim 2, wherein: The angles between the measuring points and the rotation center are the same.

4. The method for measuring the diameter of a cylinder according to claim 1, 2 or 3, wherein: The distance sensor measures the L value once every rotation angle α, and the number of measurements is k; P = nα, n = 1, 2, 3, ..., k; each P value corresponds to an L value.

5. The method for measuring the diameter of a cylinder according to claim 1, 2 or 3, wherein: Measure the cylindrical bar that needs to be segmented, and measure the diameter of each segment before cutting.

6. The method for measuring the diameter of a cylinder according to claim 1, 2 or 3, wherein: The distance sensor is fixedly mounted on the outer ring of the bearing, which is connected to the motor so as to drive the outer ring of the bearing to rotate. The inner ring of the bearing is fixedly mounted on the mounting ring of the base, and the space inside the mounting ring is for the cylinder to pass through.

7. The method for measuring the diameter of a cylinder according to claim 6, wherein: The outer ring of the bearing is a gear structure, and a driving gear meshing with the outer ring of the bearing is installed on the output shaft of the motor to drive the outer ring of the bearing to rotate.

8. The method for measuring the diameter of a cylinder according to claim 6, wherein: The distance sensor is positioned and installed on the outer ring of the bearing and faces the center of the bearing.

9. The method for measuring the diameter of a cylinder according to claim 1, 2 or 3, wherein: The bar material to be segmented is measured. The section to be cut of the bar material is a cylinder. The bar material to be segmented is conveyed by a conveyor. The distance sensor measures the distance between it and the section to be cut of the bar material on the bar material support seat of the conveyor to realize the diameter measurement of the section to be cut.

10. The method for measuring the diameter of a cylinder according to claim 9, wherein: The supporting seat of the conveying device has a front support and a rear support spaced apart along the bar material conveying direction, and a space is formed between the front support and the rear support for the distance sensor to rotate around the cylinder for one circle.

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