Machine tool swing head axis run-out and tilt error measuring device and method

Abstract

The invention discloses a machine tool swing head axis run-out and tilt error measuring device and method, and belongs to the technical field of machine tool precision measurement. The device comprises a connecting rod and a measuring mechanism. The middle of the connecting rod is connected with one end of a cutter bar of a machine tool swing head; the two measuring mechanisms are arranged at the two ends of the side, away from the cutter bar, of the connecting rod. Each measuring mechanism comprises a fixing rod, a standard ball, a fixing seat, a displacement sensor, a support and a base. The first end of the fixing rod is arranged at one end of one side, deviating from the cutter bar, of the connecting rod; the fixed seat comprises three mounting surfaces which are perpendicular to one another, and a displacement sensor is inserted into each mounting surface; one end of the bracket is arranged on the bottom surface of the fixed seat, and the other end is arranged on the base; the base is arranged on a workbench of a machine tool. According to the invention, the problems of complex operation, long time consumption and limited measurement precision of the existing measurement means can be solved.

Description

Technical Field

[0001] This application relates to the field of precision measurement technology for machine tools, and in particular to a device and method for measuring the runout and tilt error of a machine tool swivel head axis. Background Technology

[0002] In the field of precision measurement for machine tools, the oscillating axis of a machine tool exhibits six key motion errors during machining operations. These include three runout errors (such as radial runout along the X, Y, and Z axes), two tilting errors (such as tilting around the Y and Z axes), and one rotational positioning error (such as positioning deviation around the A-axis). These errors directly lead to a decrease in the motion accuracy of the tool tip, which in turn causes machining errors, affecting the final dimensional accuracy and surface quality of the parts. Therefore, accurate measurement and compensation of these motion errors are crucial for improving the overall performance of the machine tool and ensuring machining accuracy.

[0003] Existing measurement technologies primarily focus on detecting rotational positioning errors, with mature solutions and equipment available for accurate measurement. However, for the other five motion errors of the oscillating head axis (i.e., runout and tilt errors), existing technologies largely rely on tools such as ballbars. These methods require designing multiple complex detection paths, such as repeatedly adjusting the position and angle within different planes of the machine tool (e.g., XY, YZ, or XZ planes) to capture error data.

[0004] Overall, while existing measurement methods can partially identify errors, their reliance on ballbars necessitates multi-path detection, requiring operators to repeatedly set and adjust machine tool movements, increasing the risk of human error and time costs. Furthermore, the complexity of the paths limits measurement accuracy, leading to incomplete error identification and hindering efficient and precise location of machining error sources. Therefore, existing measurement methods suffer from significant drawbacks: operational complexity, time-consuming nature, and limited measurement accuracy. These shortcomings directly impact the improvement of machining accuracy. Summary of the Invention

[0005] This application provides a device and method for measuring the runout and tilt error of a machine tool swivel head axis, which can solve the problems of existing measurement methods being complex to operate, time-consuming, and having limited measurement accuracy.

[0006] To achieve the above objectives, the technical solution of this invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide a machine tool swivel head axis runout and tilt error measuring device, including a connecting rod and a measuring mechanism;

[0008] The middle part of the connecting rod is connected to one end of the tool holder of the machine tool oscillating head;

[0009] The measuring mechanism includes two measuring mechanisms, which are disposed at both ends of the connecting rod on the side opposite to the tool bar;

[0010] Each of the aforementioned measuring mechanisms includes a fixed rod, a standard ball, a fixed seat, a displacement sensor, a bracket, and a base;

[0011] The first end of the fixing rod is located at one end of the connecting rod away from the tool bar, and the second end is provided with the standard ball;

[0012] The mounting base includes three mutually perpendicular mounting surfaces, and a displacement sensor is inserted into each mounting surface;

[0013] One end of the bracket is disposed on the bottom surface of the fixed base, and the other end is disposed on the base;

[0014] The base is mounted on the machine tool's worktable.

[0015] In conjunction with the first aspect, in one possible implementation, the fixing rod includes a first fixing sub-rod, a second fixing sub-rod, and an adjusting screw;

[0016] The first end of the first fixed sub-rod is located at one end of the connecting rod away from the tool bar, and the second end is provided with a mounting hole that is recessed inward from the end face;

[0017] The first end of the second fixing rod extends into the mounting hole, and the second end is provided with the standard ball;

[0018] There are multiple adjusting screws, which are disposed on the side wall of the mounting hole and have their front ends extending into the inner cavity of the mounting hole.

[0019] In conjunction with the first aspect, in one possible implementation, there are three adjusting screws, which are respectively located above, below and on the side of the mounting hole, and are at a 90° angle to each other.

[0020] In conjunction with the first aspect, in one possible implementation, the bottom of the base is provided with a magnetic attraction structure.

[0021] Secondly, embodiments of the present invention provide a method for measuring the runout and tilt error of a machine tool swivel head axis, based on the aforementioned machine tool swivel head axis runout and tilt error measuring device, comprising:

[0022] The middle part of the connecting rod of the device is connected to one end of the tool holder of the machine tool swivel head, and the base is set on the worktable of the machine tool;

[0023] Adjust the distance between the two standard balls and the axis of rotation of the machine tool oscillating head to be L;

[0024] The distance from the standard ball to the spindle axis of the machine tool tilting head is adjusted to M.

[0025] When the machine tool tilting head is in a horizontal position, the machine tool table moves along the X-axis so that each of the standard balls approaches the three displacement sensors at its corresponding position. The connection between the connecting rod and the tool holder is adjusted so that the connecting rod is parallel to the table to ensure that the two standard balls are at the same height in the Y direction.

[0026] Adjust the position of the base of each measuring mechanism and the height of the machine tool's worktable in the Y-axis direction so that each of the standard balls contacts the three displacement sensors at its corresponding position, so that the initial readings of the three sensors are all zero;

[0027] The machine tool is driven to perform RTCP motion, causing the rotation axis of the machine tool oscillating head to swing to an oscillation angle θ. The offset values ​​(ΔX1, ΔY1, ΔZ1) and (ΔX2, ΔY2, ΔZ2) of the standard ball corresponding to its own position, measured by the three displacement sensors of each measuring mechanism, are recorded in real time.

[0028] Based on the offset values ​​(ΔX1, ΔY1, ΔZ1) and (ΔX2, ΔY2, ΔZ2), establish a system of equations:

[0029] In the formula, ATX is the axial runout error of the rotation axis of the machine tool swivel head, ATY is the radial runout error of the axis of the machine tool swivel head along the Y-axis, ATZ is the radial runout error of the axis of the machine tool swivel head along the Z-axis, ARX is the rotational positioning error of the rotation axis of the machine tool swivel head, ARY is the tilt error of the axis of the machine tool swivel head around the Y-axis, ARZ is the tilt error of the axis of the machine tool swivel head around the Z-axis, L is the distance from the standard ball to the axis of rotation of the machine tool swivel head, θ is the swing angle, and M is the distance from the standard ball to the spindle axis of the machine tool swivel head.

[0030] Solving the system of simultaneous equations, we find the five motion errors as follows:

[0031] In conjunction with the second aspect, in one possible implementation, the extension of the standard ball is finely adjusted by multiple adjusting screws so that the distance from both standard balls to the axis of rotation of the machine tool oscillating head is L.

[0032] In conjunction with the second aspect, in one possible implementation, the distance from the standard ball to the spindle axis of the machine tool oscillating head is M by adjusting the position of the base of each of the measuring mechanisms.

[0033] In conjunction with the second aspect, in one possible implementation, the height of the standard ball along the Y-axis is adjusted by multiple adjusting screws working together.

[0034] In conjunction with the second aspect, in one possible implementation, the middle part of the connecting rod of the device is connected to one end of the tool holder of the machine tool swivel head, and the base is set in front of the machine tool's worktable. First, the rotational positioning error ARX of the rotating axis of the machine tool swivel head is measured by a laser interferometer, and the rotational positioning error ARX is compensated on the CNC system so that the rotational positioning error ARX=0.

[0035] Substituting ARX=0 into the system of equations, the five motion errors are:

[0036] In conjunction with the second aspect, in one possible implementation, the middle of the connecting rod of the device is connected to one end of the tool holder of the machine tool swivel head, the base is set in front of or behind the worktable of the machine tool, and the actual value of the rotational positioning error ARX of the machine tool swivel head is measured using a laser interferometer;

[0037] Substitute the actual values ​​into the system of equations to solve for the five motion errors.

[0038] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0039] The machine tool swivel head axis runout and tilt error measuring device provided in this application embodiment has a connecting rod fixedly connected to one end of the tool holder of the machine tool swivel head, ensuring a stable connection between the device and the machine tool swivel head. Simultaneously, a base is installed on the machine tool worktable, providing stable support. After the device is installed, two measuring mechanisms are located on the opposite sides of the tool holder at both ends of the connecting rod, and the fixed rod in each measuring mechanism positions the standard ball at a specific position. When the machine tool performs a motion (such as RTCP motion), the rotation axis (A-axis) of the swivel head swings, causing the standard ball to displace in space. Since each measuring mechanism's fixed base is equipped with three displacement sensors (corresponding to the X, Y, and Z axes respectively) on mutually perpendicular mounting surfaces, the offset values ​​of the standard ball in the three axes can be detected in real time. These displacement sensors directly collect displacement data, such as the position change of the standard ball during the swing process. Through the fixed connection of the bracket and base, a stable and reliable measurement environment is ensured. The entire process avoids external path adjustments; only one setup is required to simultaneously obtain multi-axial offset values ​​through the two measuring mechanisms, providing raw data for subsequent error calculation. By integrating two measuring mechanisms at both ends of the connecting rod with components such as a fixed base and displacement sensors, this device eliminates the need for external tools like ballbars or multiple complex detection paths. Its compact design allows for comprehensive measurement coverage after a single installation, eliminating the tedious steps of repeated manual setup and significantly reducing operational complexity. The fixed connections (connecting rod and tool bar, base and worktable) and one-time setup reduce the time spent on multiple path switching and adjustments. The real-time data acquisition capability of the displacement sensors, combined with the simultaneous operation of the two measuring mechanisms, efficiently captures error information, avoiding the delays caused by multiple motion tests in existing technologies. Regarding measurement accuracy, three mutually perpendicular displacement sensors directly measure the three-dimensional offset of the standard ball, providing accurate and reliable data. Combined with the rigid structure of the fixed base and support, environmental interference is minimized. Furthermore, the symmetrical layout of the two measuring mechanisms allows for cross-validation of data, comprehensively identifying runout and tilt errors (such as ATX, ATY, ATZ, ARY, ARZ), overcoming the incomplete identification and insufficient accuracy caused by path dependence in existing technologies. Ultimately, this application embodiment achieves rapid and accurate measurement of the five motion errors of the machine tool swivel head's axis, effectively improving machining accuracy. This application is highly operable and practical, with high detection accuracy, enabling rapid and accurate measurement of the remaining five motion errors of the machine tool swivel head's axis. This allows for accurate identification of the sources of machining errors, improving part machining accuracy. The structure is rationally designed and easy to install, making it suitable for widespread use. Furthermore, compared to existing methods that require multiple installations to measure multiple errors, this application embodiment can measure multiple errors at once, and calculations can be performed using a simple set of equations, simplifying the calculation process. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the structure of the machine tool swivel head axis runout and tilt error measuring device provided in the embodiments of this application;

[0042] Figure 2 A schematic diagram of the machine tool oscillating head axis runout and tilt error measuring device provided in this application embodiment installed on the machine tool;

[0043] Figure 3 for Figure 2 Enlarged view at point M;

[0044] Figure 4 A schematic diagram illustrating the principle of the machine tool swivel axis runout and tilt error measuring device provided in this application for measuring the error in the YZ plane on a five-axis machine tool;

[0045] Figure 5 A schematic diagram illustrating the principle of the machine tool swivel axis runout and tilt error measuring device provided in this application for measuring errors in the XY plane on a five-axis machine tool;

[0046] Figure 6 This is a schematic diagram illustrating the principle of the machine tool swivel axis runout and tilt error measuring device provided in this application for measuring the error in the XZ plane on a five-axis machine tool.

[0047] Reference numerals in the attached figures: 1-Measuring device for machine tool swivel head axis runout and tilt error; 11-Connecting rod; 12-Measuring mechanism; 121-Fixed rod; 121a-First fixed sub-rod; 121b-Second fixed sub-rod; 121c-Adjusting screw; 122-Standard ball; 123-Fixed seat; 124-Displacement sensor; 125-Bracket; 126-Base; 13-Fasting screw; 2-Machine tool swivel head; 21-Tool holder; 3-A-axis; 4-Worktable. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] In the description of the embodiments of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0050] Please refer to Figures 1-3 As shown, this application embodiment provides a machine tool oscillating head axis runout and tilt error measuring device 1, including a connecting rod 11 and a measuring mechanism 12. The middle part of the connecting rod 11 is connected to one end of the tool holder 21 of the machine tool oscillating head 2. Specifically, as shown... Figure 1 As shown, the middle part of the connecting rod 11 is fixed to one end of the tool bar 21 of the machine tool swivel head 2 by a fastening screw 13.

[0051] The measuring mechanism 12 includes two components, which are located at both ends of the connecting rod 11 on the side opposite to the tool holder 21. Each measuring mechanism 12 includes a fixed rod 121, a standard ball 122, a fixed base 123, a displacement sensor 124, a bracket 125, and a base 126. The first end of the fixed rod 121 is located at one end of the connecting rod 11 on the side opposite to the tool holder 21 (specifically, the first end of the fixed rod 121 is fixed to one end of the connecting rod 11 on the side opposite to the tool holder 21), and the second end is equipped with the standard ball 122. The fixed base 123 includes three mutually perpendicular mounting surfaces, and a displacement sensor 124 is inserted into each mounting surface. The displacement sensor 124 is a precision eddy current displacement sensor. One end of the bracket 125 is located on the bottom surface of the fixed base 123, and the other end is located on the base 126. The base 126 is located on the machine tool's worktable 4.

[0052] Optionally, the base 126 is equipped with a magnetic attraction structure at its bottom. The magnetic attraction structure uses strong magnetic attraction force to enable the base 126 to be quickly and firmly fixed to the surface of the metal worktable 4 of the machine tool, which optimizes the setup efficiency and adaptability of the device and reduces the complexity of manual operation.

[0053] The machine tool swivel head axis runout and tilt error measuring device 1 provided in this embodiment has a connecting rod 11 fixedly connected to one end of the tool holder 21 of the machine tool swivel head 2, ensuring a stable connection between the device and the machine tool swivel head 2. Simultaneously, a base 126 is mounted on the machine tool worktable 4, providing stable support. After the device is installed, two measuring mechanisms 12 are located on the opposite sides of the tool holder 21 at both ends of the connecting rod 11, and the fixed rod 121 in each measuring mechanism 12 positions the standard ball 122 at a specific position. When the machine tool performs a motion (such as RTCP motion), the rotation axis (A-axis 3) of the swivel head swings, causing the standard ball 122 to displace in space. Since the fixed base 123 of each measuring mechanism 12 is equipped with three displacement sensors 124 (corresponding to the X, Y, and Z axes respectively) on mutually perpendicular mounting surfaces, the offset values ​​of the standard ball 122 in the three axes can be detected in real time. These displacement sensors 124 directly collect displacement data, such as the position change of the standard ball 122 during its swing. The fixed connection between the bracket 125 and the base 126 ensures a stable and reliable measurement environment. The entire process avoids external path adjustments; only a single setup is needed to simultaneously acquire multi-axial offset values ​​through the two measuring mechanisms 12, providing raw data for subsequent error calculations. By setting two measuring mechanisms 12 at both ends of the connecting rod 11 and integrating components such as the fixed base 123 and displacement sensors 124, the device eliminates the need for external tools like ballbars or multiple complex detection paths. Its compact overall design covers all measurement needs after a single installation, eliminating the tedious steps of repeated manual setup and significantly reducing operational complexity. The fixed connection (connecting rod 11 to tool bar 21, base 126 to worktable 4) and one-time setup reduce the time spent on multiple path switching and adjustments. The real-time data acquisition capability of the displacement sensors 124, combined with the simultaneous operation of the two measuring mechanisms 12, efficiently captures error information, avoiding the delays caused by multiple motion tests in existing technologies. Regarding measurement accuracy, three mutually perpendicular displacement sensors 124 directly measure the three-dimensional offset value of the standard ball 122, ensuring accurate and reliable data. Combined with the rigid structure of the fixed base 123 and the bracket 125, environmental interference is minimized. Simultaneously, the symmetrical layout of the two measuring mechanisms 12 allows for cross-validation of data, comprehensively identifying runout and tilt errors (such as ATX, ATY, ATZ, ARY, and ARZ), overcoming the incomplete identification and insufficient accuracy caused by path dependence in existing technologies. Ultimately, this embodiment achieves rapid and accurate measurement of the five motion errors of the machine tool swivel head 2's axis, effectively improving machining accuracy. This application is highly operable and practical, with high detection accuracy, enabling rapid and accurate measurement of the remaining five motion errors of the machine tool swivel head 2's axis, thereby accurately identifying the source of machining errors, improving part machining accuracy, and featuring a reasonable structural design and convenient installation, making it suitable for widespread use.In addition, compared to existing methods that require multiple installations to measure multiple errors, the embodiments of this application can measure multiple errors at once, and the calculation can be achieved through a simple set of equations, simplifying the calculation process.

[0054] Further, the fixing rod 121 includes a first fixing sub-rod 121a, a second fixing sub-rod 121b, and adjusting screws 121c. The first end of the first fixing sub-rod 121a is located at the end of the connecting rod 11 opposite to the tool holder 21 (specifically, the first end of the first fixing rod 121 is fixed to the end of the connecting rod 11 opposite to the tool holder 21), and the second end has a mounting hole recessed inward from its end face. The first end of the second fixing sub-rod 121b extends into the mounting hole, and the second end has a standard ball 122. Multiple adjusting screws 121c are located on the side wall of the mounting hole, with their front ends extending into the inner cavity of the mounting hole.

[0055] The fixing rod 121 provided in this embodiment allows the operator to fine-tune the radial extension or Y-axis height of the standard ball 122 by rotating the adjusting screws 121c during the initial setup of the measuring device. This directly affects the position of the second fixing rod 121b within the mounting hole. For example, when adjusting the distance L between the two standard balls 122 and the axis of rotation (A-axis 3) of the machine tool oscillating head 2, the operator needs to coordinate the adjustment of multiple adjusting screws 121c to precisely control the radial displacement of the standard balls 122, ensuring that the distance L between the two measuring points is consistent. By screwing the adjusting screws 121c in or out, the second fixing rod 121b can make slight axial movements within the hole, compensating for mechanical deviations during installation and ensuring that the standard ball 122 is positioned to the required accuracy. This structure significantly improves the adjustment flexibility and measurement accuracy of the device. The fine-tuning mechanism effectively eliminates the problem of asymmetrical position of the standard ball 122 caused by installation errors, ensuring the symmetry of the two measuring mechanisms 12, thereby providing a reliable data basis for subsequent error calculations. At the same time, it simplifies the operation process, reduces the need for repeated manual calibration, reduces measurement uncertainty introduced by human factors, and ultimately solves the problems of complex operation and limited accuracy in existing technologies, thereby improving overall measurement efficiency.

[0056] Furthermore, there are three adjusting screws 121c, located above, below, and to the side of the mounting hole, respectively, at a 90° angle to each other. During operation, the upper adjusting screw 121c controls the vertical (Y-axis) movement of the standard ball 122, the lower adjusting screw 121c provides a reverse constraint, and the side adjusting screw 121c adjusts the horizontal (e.g., X-axis or radial) position. For example, when setting the height of the standard ball 122 in the Y-axis direction, the operator can independently adjust the Z-axis height of the standard ball 122 by coordinating the rotation of the upper and lower screws. Simultaneously, the side adjusting screw 121c is used for fine-tuning the radial position, ensuring the standard ball 122 remains stable during oscillation. In the measurement method, when the machine tool oscillating head 2 is in a horizontal position, the operator uses these adjusting screws 121c to quickly adjust the height of the standard ball 122, making the two standard balls 122 equal in height (i.e., the Y-axis displacement sensor 124 readings are consistent), and ensuring the initial position is zeroed. This adjustment process is efficient and intuitive, requiring no additional tools. The 90° symmetrical distribution of the three screws provides comprehensive position control, significantly enhancing the stability and repeatability of the device. It allows the operator to perform multi-directional fine-tuning in a single action, greatly reducing setup time and avoiding the tedious process of repeatedly adjusting the path in existing technologies. Furthermore, this design strengthens the rigidity of the fixed rod 121, reducing error drift caused by vibration or displacement during measurement, thereby improving the accuracy of data acquisition. This further optimizes the device's practicality, enabling it to quickly adapt to different working conditions in complex machine tool environments, resulting in overall improved measurement accuracy and reduced operation time.

[0057] Another embodiment of this application provides a method for measuring the runout and tilt error of a machine tool swivel head axis, based on the aforementioned machine tool swivel head axis runout and tilt error measuring device 1, comprising:

[0058] The middle part of the connecting rod 11 of the device is connected to one end of the tool holder 21 of the machine tool swivel head 2, and the base 126 is set on the worktable 4 of the machine tool. For example, the machine tool is a BXFZYA type five-axis machine tool.

[0059] The distances from the two standard balls 122 to the axis of rotation (A-axis 3) of the machine tool swivel head 2 are adjusted to L. Specifically, before measurement, the swing angle θ of the machine tool swivel head 2 is defined as -90 degrees when it is vertically downward, 0 degrees when it is horizontal, and positive when it is obliquely upward. The swing angle θ is the angle of swing of the axis of rotation (A-axis 3) of the machine tool swivel head 2 relative to the horizontal reference position (θ=0). The distance from the standard ball 122 to the axis of A-axis 3 after installation is measured by dial indicator or tool setter. The extension of the standard ball 122 is finely adjusted by multiple adjusting screws to ensure that the distances from the two standard balls 122 to the axis of rotation (A-axis 3) of the machine tool swivel head 2 are both L. This provides a stepless adjustment mechanism, significantly improving installation accuracy and flexibility, effectively compensating for mechanical assembly deviations (such as asymmetry in the position of the standard ball 122 caused by machining tolerances or installation errors), and avoiding amplification of measurement errors caused by uneven distances. At the same time, this design simplifies the adjustment process, allowing operators to quickly complete calibration without additional tools, reducing setup time and enhancing the repeatability of the device, further consolidating the accuracy advantages of the overall measurement method.

[0060] The distance from the standard ball 122 to the spindle axis of the machine tool swivel head 2 is adjusted to M. The position of the base 126 of each measuring mechanism 12 in the device is adjusted to ensure that the distance from the standard ball 122 to the spindle axis of the machine tool swivel head 2 is always M. Independent adjustment of the base 126 position enhances the symmetry and consistency of the measurement environment, eliminates systematic errors caused by differences in distance M (such as affecting the calculation of tilt errors ARY and ARZ), and improves data comparability and reliability. Combined with the stable characteristics of the magnetic structure, the method of this embodiment ensures convenient adjustment while reducing vibration interference caused by the movement of the base 126, maintaining the stability of the entire device under complex machine tool operating conditions, thereby further optimizing measurement accuracy and operational efficiency.

[0061] When the machine tool oscillating head 2 is in a horizontal position, i.e., the oscillation angle θ is 0 degrees, the machine tool's worktable 4 moves along the X-axis, causing each standard ball 122 to approach the three displacement sensors 124 at its corresponding position. The connection between the adjusting rod 11 and the tool holder is made so that the rod 11 is parallel to the worktable 4, ensuring that the two standard balls 122 are at the same height in the Y-axis. The readings of the displacement sensors 124 set along the Y-axis are then observed to ensure that the two standard balls 122 are at the same height. Specifically, multiple adjusting screws 121c work together to adjust the height of the standard balls 122 along the Y-axis, thus achieving precise and independent height adjustment and avoiding the cumbersome steps of multiple movements of the worktable 4 in existing technologies. Through the direct mechanical adjustment of the adjusting screws 121c, the operator can quickly respond to the feedback from the displacement sensors 124, ensuring the accuracy of the initialization process and reducing human calibration errors. This not only significantly shortens the setup time but also enhances the consistency of the starting point of the measurement data, laying a reliable foundation for subsequent offset value acquisition and indirectly improving the accuracy of error calculation.

[0062] Adjust the position of the base 126 of each measuring mechanism 12 and the height of the worktable 4 of the machine tool in the Y-axis direction so that each standard ball 122 contacts the three displacement sensors 124 at its corresponding position, so that the initial readings of the three displacement sensors 124 are all zero.

[0063] like Figure 4 As shown, the machine tool is driven to perform RTCP motion, causing the rotation axis (A-axis 3) of the machine tool swivel head 2 to swing to the swing angle θ. At the same time, the Y-axis and Z-axis of the machine tool swivel head 2 work together to record in real time the offset values ​​(ΔX1, ΔY1, ΔZ1) and (ΔX2, ΔY2, ΔZ2) of the standard ball 122 corresponding to its own position measured by the three displacement sensors 124 of each measuring mechanism 12 in the XYZ axes.

[0064] See Figure 5 When axis A3 swings to any angle θ, the axial error ARZ causes the two standard spheres 122 (standard sphere O1 and standard sphere O2) to have a displacement of -ARZ·L·cosθ in the X-direction within the XY plane. The displacement of standard sphere O1 in the Y-direction is ARY·M, and the displacement of standard sphere O2 in the Y-direction is -ARY·M. The displacement in the Z-direction is ATZ+ARX·L·sinθ.

[0065] See Figure 6 When axis A3 swings to any angle θ, the axial error ARY causes the two standard spheres 122 (standard sphere O1 and standard sphere O2) to have an offset of -ARY·L·cosθ in the X-direction within the XZ plane, and the offset of standard sphere 122-1 in the Z-direction is -ARY·M, and the offset of standard sphere 122-2 in the Z-direction is ARY·M. The offset in the Z-direction is ATZ+ARX·L·sinθ.

[0066] Based on the offset values ​​(ΔX1, ΔY1, ΔZ1) and (ΔX2, ΔY2, ΔZ2), establish a system of equations:

[0067] In the formula, ATX is the axial runout error of the rotation axis (A-axis 3) of the machine tool swivel head 2, ATY is the radial runout error of the axis of the machine tool swivel head 2 along the Y-axis, ATZ is the radial runout error of the axis of the machine tool swivel head 2 along the Z-axis, ARX is the rotational positioning error of the rotation axis (A-axis 3) of the machine tool swivel head 2, ARY is the tilt error of the axis of the machine tool swivel head 2 around the Y-axis, ARZ is the tilt error of the axis of the machine tool swivel head 2 around the Z-axis, L is the distance from the standard ball 122 to the axis of the rotation axis of the machine tool swivel head 2, θ is the swing angle, and M is the distance from the standard ball 122 to the spindle axis of the machine tool swivel head 2.

[0068] Solving the system of simultaneous equations, we find the five motion errors as follows: .

[0069] The machine tool oscillating head axis runout and tilt error measurement method provided in this application embodiment avoids the repeated multi-path adjustments (such as switching between XY, YZ, or XZ planes) required by prior art by setting up the device once and integrating a symmetrical layout of two measuring mechanisms 12, significantly reducing operational complexity. Simultaneously, the displacement sensor 124 collects three-dimensional offset values ​​in real time, and combined with fixed connection structures (such as connecting rod 11 and tool holder 21, base 126 and worktable 4), ensures data stability and reduces errors caused by human intervention or environmental vibration, thereby achieving high-precision identification of five motion errors (including runout and tilt errors). This not only shortens the measurement time from multiple repetitive operations in prior art to a single process, but also solves the problems of incomplete identification and insufficient accuracy by directly solving the error through a system of equations, providing a reliable basis for subsequent machining error compensation and ultimately improving the overall machining accuracy of the machine tool. Compared to existing methods that require multiple installations to measure multiple errors, this application embodiment can measure multiple errors at once, and the calculation can be achieved through a simple system of equations, simplifying the calculation process.

[0070] The middle part of the connecting rod 11 of the device is connected to one end of the tool bar 21 of the machine tool swivel head 2. The base 126 is set in front of the worktable 4 of the machine tool. The rotational positioning error ARX of the rotation axis (A axis 3) of the machine tool swivel head 2 is measured by a laser interferometer. The rotational positioning error ARX is compensated on the CNC system so that the rotational positioning error ARX=0.

[0071] Substituting ARX=0 into the system of equations, the five motion errors are:

[0072] By pre-eliminating the common error term ARX, the number of unknowns in the equation system is simplified, making the solution process more direct and efficient (e.g., reducing the number of unknowns from six to five), and avoiding interference from cross-errors. This not only reduces computational complexity and solution deviations caused by numerical instability of simultaneous equations, but also improves the overall practicality of the method (operators can reuse existing calibration tools), ensuring that while maintaining high accuracy, the overall measurement time is further reduced, demonstrating the innovation and economy of the technical solution.

[0073] Alternatively, the middle of the connecting rod 11 of the device is connected to one end of the tool bar 21 of the machine tool swivel head 2, and the base 126 is set in front of or behind the worktable 4 of the machine tool, and the actual value of the rotational positioning error ARX of the machine tool swivel head 2 is measured using a laser interferometer.

[0074] Substitute the actual value into the system of equations to solve for the five motion errors. The rotational positioning error ARX used in the calculations of ATY and ATZ is this actual value.

[0075] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0076] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A machine tool head runout and tilt error measuring device, characterized by, The connecting rod and the measuring mechanism are included. The middle part of the connecting rod is connected with one end of a tool bar of a machine tool head; The measuring mechanism includes two, and the two measuring mechanisms are arranged at two ends of a side of the connecting rod away from the tool bar; Each measuring mechanism includes a fixed rod, a standard ball, a fixed seat, a displacement sensor, a support and a base; The first end of the fixed rod is arranged at one end of the side of the connecting rod away from the tool bar, and the second end is arranged with the standard ball; The fixed seat includes three mutually perpendicular mounting surfaces, and one displacement sensor is arranged on each mounting surface; One end of the support is arranged on the bottom surface of the fixed seat, and the other end is arranged on the base; The base is arranged on a workbench of the machine tool.

2. The machine tool head runout and tilt error measuring apparatus of claim 1 wherein, The fixed rod includes a first fixed sub-rod, a second fixed sub-rod and an adjusting screw; The first end of the first fixed sub-rod is arranged at one end of the side of the connecting rod away from the tool bar, and the second end is arranged with a mounting hole recessed inward from the end face; The first end of the second fixed sub-rod is arranged in the mounting hole, and the second end is arranged with the standard ball; The adjusting screw is arranged on the side wall of the mounting hole and has a front end extending into the inner cavity of the mounting hole.

3. The machine tool head runout and tilt error measuring apparatus of claim 1 wherein, The adjusting screw is arranged above, below and on the side of the mounting hole, and the three adjusting screws are arranged at an angle of 90°.

4. The machine tool head runout and tilt error measurement apparatus of claim 1 wherein, The bottom of the base is provided with a magnetic structure.

5. A method of measuring runout and tilt errors of a headstock axis of a machine tool, characterized in that, The machine tool head axis runout and tilt error measuring device according to any one of claims 1-4, comprising: The middle part of the connecting rod of the device is connected with one end of a tool bar of a machine tool head, and the base is arranged on a workbench of the machine tool; The distance between the two standard balls and the rotation axis of the machine tool head is L; The distance between the standard balls and the spindle axis of the machine tool head is M; When the machine tool head is in a horizontal position, the workbench of the machine tool is moved along the X-axis direction to make each standard ball approach three displacement sensors at the corresponding positions, and the connection between the connecting rod and the tool handle is adjusted to make the connecting rod parallel to the workbench, so as to ensure that the two standard balls are consistent in the Y direction; The position of the base of each measuring mechanism and the Y-axis direction height of the workbench of the machine tool are adjusted, so that each standard ball contacts three displacement sensors at the corresponding positions, and the initial readings of the three sensors are all zero; The machine tool is driven to perform an RTCP motion, the rotation axis of the machine tool head is swung to a swing angle θ, and the offset values (ΔX1, ΔY1, ΔZ1) and (ΔX2, ΔY2, ΔZ2) of the standard balls corresponding to the positions of each measuring mechanism measured by the three displacement sensors of each measuring mechanism are recorded in real time; Based on the offset values (ΔX1, ΔY1, ΔZ1) and (ΔX2, ΔY2, ΔZ2), an equation group is established: ； In the formula, ATX is the axial runout error of the rotating shaft of the machine tool head, ATY is the radial runout error of the axis of the machine tool head along the Y-axis direction, ATZ is the radial runout error of the axis of the machine tool head along the Z-axis direction, ARX is the rotary positioning error of the rotating shaft of the machine tool head, ARY is the tilt error of the axis of the machine tool head around the Y-axis, ARZ is the tilt error of the axis of the machine tool head around the Z-axis, L is the distance from the standard ball to the axis of the rotating shaft of the machine tool head, θ is the swing angle, and M is the distance from the standard ball to the spindle axis of the machine tool head. The five motion errors are solved by the simultaneous equations as follows: 。 6. The machine tool head offset and tilt error measurement method of claim 5 wherein, The extension amount of the standard ball is adjusted by the multiple adjusting screws to make the distance from the two standard balls to the axis of the rotating shaft of the machine tool head both L.

7. The machine tool head offset and tilt error measurement method of claim 5 wherein, The distance from the standard ball to the spindle axis of the machine tool head is adjusted by adjusting the position of the base of each measuring mechanism of the adjusting device.

8. The machine tool head offset and tilt error measurement method of claim 5 wherein, The height of the standard ball in the Y-axis direction is adjusted by the multiple adjusting screws.

9. The machine tool head offset and tilt error measurement method of claim 5 wherein, When the middle part of the connecting rod of the device is connected to one end of the tool bar of the machine tool head and the base is arranged in front of the worktable of the machine tool, the rotary positioning error ARX of the rotating shaft of the machine tool head is measured by a laser interferometer, and the rotary positioning error ARX is compensated on the numerical control system so that the rotary positioning error ARX=0. The five motion errors are solved by substituting ARX=0 into the equations as follows: 。 10. The machine tool head offset and tilt error measurement method of claim 5 wherein, When the middle part of the connecting rod of the device is connected to one end of the tool bar of the machine tool head and the base is arranged in front of or behind the worktable of the machine tool, the actual value of the rotary positioning error ARX of the machine tool head is measured by a laser interferometer. The five motion errors are solved by substituting the actual value into the equations.

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