An on-line secondary non-interpolation machining device and method for a spherical segment on a rotary shaft

Abstract

The application discloses an on-line secondary non-interpolation machining device and method for a spherical segment on a rotary shaft, comprising a cutter rotary radius measurement calibration device and a trimming device, wherein the trimming radius of the trimming cutter is accurately calibrated through the cutter rotary radius measurement calibration device, then the trimming radius of the cutter is adjusted to the radius to be machined of a workpiece, the trimming motor is rotated to drive the trimming cutter to move along the tangent direction of the circumference of the radius to be machined, so that the on-line secondary non-interpolation trimming of the workpiece is realized. The application has the advantages of simple structure and strong stability, can solve the problems of corrugation of a machining surface caused by interpolation movement of a lathe and offline machining, and can be applied to on-line secondary non-interpolation machining of parts including but not limited to a ball, a spherical segment, a spherical crown and the like.

Description

Technical Field

[0001] This invention relates to the field of precision and ultra-precision machining technology, and in particular to an online secondary non-interpolation machining apparatus and method for spherical segments on rotary shafts. Background Technology

[0002] Rotary shafts and their ball joints are common mechanical parts. After a certain period of operation, these parts may experience wear on the ball joints, requiring secondary processing to restore their roundness. For example, polishing rotary shafts and polishing balls in polishing equipment; during the polishing process, the polishing balls continuously wear down; when the wear reaches a certain level, they need to be reprocessed to regain their good sphericity.

[0003] The common method for reprocessing is to remove the ball notch from the shaft, or to remove the ball notch and the rotating shaft together from the equipment, clamp the disassembled workpiece on a lathe, and use lathe interpolation to process the ball notch.

[0004] Chinese patent application CN108296929A discloses a synchronous online inspection and processing device and method for ceramic ball heads in artificial hip joints. This method enables simultaneous grinding and ball head inspection, simplifying the processing flow and saving processing costs. Chinese patent application CN101612721A discloses a device for surface machining of spherical bushings on workpieces with ball caps. This device utilizes ultra-precision machining methods to process discontinuous surfaces, especially those interrupted circumferentially. However, both of these methods require removing the workpiece from the original device and mounting it on a lathe for machining, resulting in low processing efficiency. Furthermore, resetting and adjustment are often required when reinstalling the workpiece.

[0005] The paper "Practice and Research on CNC Machining of Ball End Joints" proposes a machining process and programming method for ball end joints, which improves the accuracy of the machined ball end parts. This method considers that the cutting tool tip is not a sharp angle but has a rounded corner. During turning, the arc of the tool tip forms an envelope, leading to overcutting or undercutting, and deviations between the actual machined contour and the theoretical contour. However, this method does not consider that the lathe uses interpolation feed, and the tool feed trajectory is not the theoretically spherical or circular shape, but rather uses multi-terminal minute linear motion to approximate a sphere or circle. This results in microscopic differences between the machined ball end joint and the ideal ball end joint, affecting the final surface smoothness.

[0006] The papers "Surface quality of silicon wafer improved by hydrodynamic effect polishing" and "Research on key technologies for ultra-smooth surface processing based on material elastic domain removal" employ a spherical segment polishing wheel for polishing. The spherical segment polishing wheel used in this device is machined on a lathe, and its surface exhibits noticeable ripples. This is due to the periodic turning marks in the circumferential direction caused by the use of single-point diamond machining technology.

[0007] Therefore, in summary, the current secondary machining of ball joints on rotary shafts has the following two shortcomings:

[0008] 1. Offline machining: The ball notch to be machined needs to be disassembled from the original device and then clamped on the machine tool; the machining efficiency is low, and resetting and adjustment are often required when reinstalling it back to the original device.

[0009] 2. Machining spheres using interpolation feed: The feed path of the machining tool is not a theoretical sphere or circle, but uses multiple small linear movements to approximate a sphere or circle. The machined spherical defect has microscopic differences from the ideal spherical defect, which affects the final surface smoothness. Summary of the Invention

[0010] To address the problem of inability to perform online secondary machining and non-interpolation machining in the prior art, this invention proposes an online secondary non-interpolation machining device and method for spherical segments on a rotary shaft. The device accurately calibrates the trimming radius of the trimming tool using a tool rotation radius measurement and calibration device. Then, the trimming radius is adjusted to the radius to be machined on the workpiece. A trimming motor rotates, driving the trimming tool along a path tangent to the circumference of the radius to be machined, thus achieving online secondary non-interpolation trimming of the workpiece. This invention has a simple structure and high stability, solving the problems of surface ripples caused by interpolation motion on lathes and the need for offline machining. It is applicable to online secondary non-interpolation machining of parts including, but not limited to, spheres, spherical segments, and spherical crown-shaped wheels.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] An online secondary non-interpolation machining device for spherical segments on a rotary shaft includes a trimming device and a tool rotation radius measurement and calibration device. A trimming frame is mounted at the bottom of the trimming device. A trimming motor is fixedly connected to the trimming frame. A trimming rotary spindle is fixedly connected to the trimming motor. A trimming linear motion platform is fixedly connected to the trimming rotary spindle. A trimming fixed frame is fixedly connected to the trimming linear motion platform. During trimming operations, a trimming tool is fixedly connected to the trimming fixed frame, and the trimming tool is used for online trimming of the workpiece.

[0013] The tool rotation radius measurement and calibration device is equipped with a calibration support frame at its bottom; a translational motion platform is fixedly connected to the calibration support frame; a standard bar is fixedly connected to the translational motion platform, and the standard bar has high cylindricity and radius dimensional accuracy for precise tool setting of the tool radius calibration device; when performing tool rotation radius measurement and calibration, a distance sensor is fixedly connected to the trimming fixing frame.

[0014] This invention also provides an online secondary non-interpolation machining method for spherical segments on a rotary shaft. The method is implemented using the aforementioned online secondary non-interpolation machining device for spherical segments on a rotary shaft, and includes the following steps:

[0015] Step a: Calibrate the length L of the trimming tool, the radius R of the standard bar, and the length S between the bottom of the distance sensor and the zero point of the measurement reference;

[0016] Step b: Align the rotation axis of the trimming spindle with the axis of the standard bar to achieve a certain degree of coaxiality. At this point, use the trimming motor to rotate the trimming spindle, which in turn drives the distance sensor to rotate around the standard bar. Since the axes of the two are not completely coincident, the reading of the distance sensor will be within a certain range.

[0017] Step c: Use a translational motion platform to adjust the position of the standard bar and the fine-tuning calibration support frame to precisely align the axes of the trimming rotary spindle and the standard bar. Use the trimming motor to rotate the trimming rotary spindle, which in turn drives the distance sensor to rotate around the standard bar. When the distance sensor reading no longer fluctuates, stop the fine alignment adjustment and record the distance sensor reading as A. At this point, it is determined that the rotation axis of the trimming rotary spindle is coaxial with the axis of the standard bar.

[0018] Step d: Remove the distance sensor and install the trimming tool on the trimming holder;

[0019] Step e: Based on the dimensions calibrated in step a and the readings of the distance sensor in step c, calculate the trimming radius of the trimming tool, i.e., R1, where R1 = R + A + SL;

[0020] Step f: Adjust the trimming radius according to the workpiece's radius of radius R2: When R2 < R1, adjust the trimming linear motion platform so that the cutting edge of the trimming tool moves X towards the rotation axis of the trimming spindle, and R2 = R1 - X; when R2 ≥ R1, adjust the trimming linear motion platform so that the cutting edge of the trimming tool moves Y away from the rotation axis of the trimming spindle, and R2 = R1 + Y; at this time, the radius of radius to be processed by the trimming tool is R2.

[0021] Step g: Set the trimming tool and the workpiece for pre-machining. After setting the tool, rotate the workpiece. Start the trimming motor. The cutting edge of the trimming tool will move along the tangent direction of the circumference of the radius to be processed R2 to feed the workpiece, realizing non-interpolation machining of the radius to be processed R2.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. It can be processed online directly at the workpiece station, avoiding the need for disassembly and resetting of the workpiece from the original device, thus improving processing efficiency.

[0024] 2. The cutting edge feed trajectory of the trimming tool is an arc of the target radius, which avoids the theoretical error caused by interpolation and improves the forming accuracy. Attached Figure Description

[0025] Figure 1 This is a three-dimensional schematic diagram of the tool rotation radius measurement and calibration device of the present invention;

[0026] Figure 2 This is an embodiment diagram of the trimming device of the present invention;

[0027] Figure 3 This is a schematic diagram of the size transfer chain between the standard rod and the distance sensor of the present invention;

[0028] Figure 4 This is a schematic diagram showing the tool setting between the trimming tool and the workpiece in this invention.

[0029] In the diagram: 1-1, trimming frame; 1-2, trimming motor; 1-3, trimming rotary spindle; 1-4, trimming linear motion platform; 1-5, trimming fixing frame; 1-6, trimming cutter;

[0030] 2-1. Calibration support frame; 2-2. Translational motion platform; 2-3. Standard bar; 2-4. Distance sensor;

[0031] 3-1. Processed parts. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] like Figures 1 to 4 As shown, this embodiment of the invention provides an online secondary non-interpolation machining device for spherical segments on a rotary shaft, including a trimming device and a tool rotation radius measurement and calibration device.

[0034] The bottom of the trimming device is provided with a trimming frame 1-1; a trimming motor 1-2 is fixedly connected to the trimming frame 1-1; a trimming rotary spindle 1-3 is fixedly connected to the trimming motor 1-2; the trimming rotary spindle 1-3 is rotatably connected within the trimming frame 1-1; a trimming linear motion platform 1-4 is fixedly connected to the other end of the trimming rotary spindle 1-3; a trimming fixing frame 1-5 is fixedly connected to the trimming linear motion platform 1-4; during trimming work, a trimming tool 1-6 is fixedly connected to the trimming fixing frame 1-5, and the trimming tool 1-6 is used for online trimming of the workpiece 3-1.

[0035] The bottom of the tool rotation radius measurement and calibration device is provided with a calibration support frame 2-1; a translational motion platform 2-2 is fixedly connected to the calibration support frame 2-1; a standard rod 2-3 is fixedly connected to the translational motion platform 2-2. The standard rod 2-3 has a cylindricity of 0-3 and a radius dimension accuracy of less than or equal to IT7, which is used for precise tool setting of the tool radius calibration device; when performing tool rotation radius measurement and calibration, a distance sensor 2-4 is fixedly connected to the trimming fixing frame 1-5.

[0036] The present invention also provides an online secondary non-interpolation machining method for a spherical segment on a rotary shaft. In one specific embodiment, the online secondary non-interpolation machining method for a spherical segment on a rotary shaft includes the following steps:

[0037] Step a: Use a coordinate measuring machine to calibrate the length L of the trimming tool 1-6, the radius R of the standard bar 2-3, and the length S between the bottom of the distance sensor 2-4 and the zero point of the measurement reference, denoted as L = 40mm, R = 50mm, and S = 30mm respectively. Figure 3 As shown;

[0038] Step b: Align the rotation axis of the trimming rotating spindle 1-3 with the axis of the standard bar 2-3 to ensure they have a certain degree of coaxiality; at this time, use the trimming motor 1-2 to rotate the trimming rotating spindle 1-3, which in turn drives the distance sensor 2-4 to rotate around the standard bar 2-3. Since the axes of the two are not completely coincident, the reading of the distance sensor 2-4 will fluctuate within a certain range.

[0039] Step c: Use the translation platform 2-2 to adjust the position of the standard rod 2-3, and fine-tune the position of the calibration support 2-1 to precisely align the axes of the trimming rotating spindle 1-3 and the standard rod 2-3. Use the trimming motor 1-2 to rotate the trimming rotating spindle 1-3, which in turn rotates the distance sensor 2-4 around the standard rod 2-3. When the reading of the distance sensor 2-4 no longer fluctuates, stop the fine alignment adjustment. Record the reading of the distance sensor 2-4 at this time as A, where A = 15mm. Figure 3 As shown; at this time, it is determined that the rotation axis of the trimming rotating spindle 1-3 is coaxial with the axis of the standard bar 2-3;

[0040] Step d: Remove distance sensor 2-4 and install trimming tool 1-6 on trimming fixture 1-5;

[0041] Step e: Based on the dimensions calibrated in step a and the readings of distance sensors 2-4 in step c, calculate the trimming radius R1 of trimming tools 1-6, where R1 = R + A + SL = 55 mm;

[0042] Step f: Adjust the trimming radius according to the machining radius R2 of workpiece 3-1. At this time, R2 = 53mm, that is, R2 = 53mm < R1 = 55mm. Adjust the trimming linear motion platform 1-4 so that the cutting edge of the trimming tool 1-6 moves 2mm closer to the rotation axis of the trimming rotary spindle 1-3, and makes R2 = R1 - X = 53mm. At this time, the machining radius of the trimming tool 1-6 is R2 = 53mm.

[0043] Step g: Perform pre-machining tool setting between the trimming tool 1-6 and the workpiece 3-1. After tool setting, rotate the workpiece 3-1 at an angular velocity of ω. Start the trimming motor 1-2. The cutting edge of the trimming tool 1-6 will feed into the workpiece 3-1 along the tangent direction of the circumference of the radius to be processed R2 = 53mm, thereby achieving non-interpolation machining of the radius to be processed R2.

[0044] The present invention provides an online secondary deterministic non-interpolation machining device and method for spherical segments on rotary shafts, which can be used for online trimming and machining of parts including but not limited to spheres, spherical segments, and spherical crown wheels.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An on-line secondary non-interpolation machining device for a spherical segment on a rotary shaft, characterized by: The utility model relates to a kind of cutting device and tool rotation radius measurement calibration device;The cutting device bottom is provided with cutting frame (1-1);The cutting frame (1-1) is fixedly connected with cutting motor (1-2);The cutting motor (1-2) is fixedly connected with cutting rotary main shaft (1-3);The cutting rotary main shaft (1-3) is fixedly connected with cutting linear motion platform (1-4);The cutting linear motion platform (1-4) is fixedly connected with cutting fixed frame (1-5);When cutting work is carried out, cutting tool (1-6) is fixedly connected on the cutting fixed frame (1-5), and the cutting tool (1-6) is used to cut online workpiece (3-1); The tool rotation radius measurement calibration device bottom is provided with calibration support frame (2-1);The calibration support frame (2-1) is fixedly connected with translation motion platform (2-2);The translation motion platform (2-2) is fixedly connected with standard bar (2-3);When tool rotation radius measurement calibration is carried out, distance sensor (2-4) is fixedly connected on the cutting fixed frame (1-5).

2. A method of machining according to claim 1, characterized in that, It comprises the following steps: Step a: the length L of cutting tool (1-6), the radius R of standard bar (2-3) and the length S of the bottom of distance sensor (2-4) and measurement reference zero point are calibrated; Step b: the rotation axis of cutting rotary main shaft (1-3) is aligned with the axis of standard bar (2-3), so that they have a certain coaxiality;At this time, cutting motor (1-2) is rotated to drive cutting rotary main shaft (1-3) to rotate, and then drive distance sensor (2-4) to rotate around standard bar (2-3), because the axis of the two does not completely coincide, the indication of distance sensor (2-4) will fluctuate within a certain range; Step c: the position of standard bar (2-3) is adjusted by translation motion platform (2-2), and the position of calibration support frame (2-1) is fine adjusted to accurately align the axis of cutting rotary main shaft (1-3) and standard bar (2-3), cutting motor (1-2) is rotated to drive cutting rotary main shaft (1-3) to rotate, and then drive distance sensor (2-4) to rotate around standard bar (2-3);When the indication of distance sensor (2-4) no longer fluctuates, stop fine adjustment, and record the indication of distance sensor (2-4) as A;At this time, it is determined that the rotation axis of cutting rotary main shaft (1-3) is coaxial with the axis of standard bar (2-3); Step d: distance sensor (2-4) is removed, and cutting tool (1-6) is installed on cutting fixed frame (1-5); Step e: according to the size calibrated in step a and the indication A of distance sensor (2-4) in step c, the cutting radius R1 of cutting tool (1-6) is calculated, R1=R+A+S-L. Step f: adjust the trimming radius according to the to-be-processed radius R2 of the workpiece (3-1): when R2 < R1, adjust the trimming linear motion platform (1-4) so that the cutting edge of the trimming cutter (1-6) moves X towards the direction close to the rotation axis of the trimming rotary main shaft (1-3), and R2 = R1-X; when R2 ≥ R1, adjust the trimming linear motion platform (1-4) so that the cutting edge of the trimming cutter (1-6) moves Y away from the rotation axis of the trimming rotary main shaft (1-3), and R2 = R1+Y; at this time, the to-be-processed radius of the trimming cutter (1-6) is R2; Step g: perform tool setting before the trimming cutter (1-6) processes the workpiece (3-1), and after the tool setting is completed, rotate the workpiece (3-1); start the trimming motor (1-2), and the cutting edge of the trimming cutter (1-6) will move along the direction of the circumference tangent of the to-be-processed radius R2 to process the workpiece (3-1), so as to realize online non-interpolation processing of the to-be-processed radius R2.

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