Compensation device for thermal expansion error of machine tool screw rod

Abstract

The invention provides a machine tool X-axis lead screw thermal expansion error compensation device which comprises a driving end bearing seat, a tail end bearing seat, a lead screw and a nut, one end of the lead screw is located in the tail end bearing seat, the nut is arranged on the lead screw in a threaded mode, a front end temperature sensor is arranged in the driving end bearing seat, and a rear end temperature sensor is arranged on the tail end bearing seat. The front-end temperature sensor, the rear-end temperature sensor, the nut temperature sensor and the computer numerical control (CNC) system are arranged on the machine tool, a nut temperature sensor is arranged on the nut, and temperature data collected by the front-end temperature sensor, the rear-end temperature sensor, the nut temperature sensor and the environment temperature sensor are transmitted to the thermal expansion error resolving device in real time. And the thermal expansion error resolving device establishes real-time communication with the machine tool CNC system through a standard data interface. According to the compensation device for the thermal expansion error of the machine tool lead screw, the feeding instruction is corrected and compensated in real time, so that the positioning error caused by thermal elongation is effectively counteracted, and finally the machining precision of equipment is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of machine tool equipment technology and relates to a compensation device for thermal expansion error of machine tool lead screw. Background Technology

[0002] When a machine tool is working, the machine tool control system needs to calculate the position coordinates of the spindle bottom center and the worktable at every moment. For machine tools driven by lead screws and nuts, the X-axis slide, Y-axis slide, and Z-axis spindle box are all fixed to the nut. The servo motor drives the lead screw to rotate and push the nut. The nut drives the X-axis slide, Y-axis slide, and Z-axis spindle box to move. The servo motor records the number of rotations of the corresponding lead screw at each moment and sends the value of the number of rotations to the machine tool control system. The machine tool control system can accurately calculate the position coordinates of the X-axis slide, Y-axis slide, and Z-axis spindle box according to the lead screw pitch and initial coordinate information. The initial coordinate information of each axis slide of the lathe is set after the lathe is completed. After that, the machine tool control system can determine the position coordinates of the worktable and the spindle bottom center according to the number of rotations of the lead screw. When a machine tool is working, the lead screw and nut need to drive the axis slide to move, generating a lot of frictional heat. This causes a temperature difference between the lead screw and the axis slide / or axis slide seat, resulting in thermal expansion and contraction of the lead screw. This changes its effective length and pitch, reducing the positioning accuracy of the feed motion. Consequently, the coordinate values ​​of the worktable and the bottom center position of the spindle calculated by the machine tool control system will deviate. The dimensions of the workpiece being machined will also be incorrect due to the thermal expansion of the lead screw, reducing the accuracy of the machine tool during actual operation. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned problems in the prior art by providing a compensation device for thermal expansion error of machine tool lead screws.

[0004] The objective of this invention can be achieved through the following technical solution: A compensation device for thermal expansion error of a machine tool lead screw, comprising a drive end bearing housing, a tail end bearing housing, a lead screw, and a nut. One end of the lead screw is located inside the tail end bearing housing, and the other end of the lead screw passes through the drive end bearing housing and is connected to a drive motor. The nut is threaded onto the lead screw. A front end temperature sensor is provided inside the drive end bearing housing, a rear end temperature sensor is provided on the tail end bearing housing, and a nut temperature sensor is provided on the nut. The device also includes an ambient temperature sensor, a thermal expansion error calculation device, and a machine tool CNC system. The temperature data collected by the front end temperature sensor, the rear end temperature sensor, the nut temperature sensor, and the ambient temperature sensor are transmitted in real time to the thermal expansion error calculation device. The thermal expansion error calculation device establishes real-time communication with the machine tool CNC system through a standard data interface.

[0005] In the aforementioned compensation device for thermal expansion error of the machine tool lead screw, the front-end temperature sensor is pre-embedded in the drive-end bearing housing, and the rear-end temperature sensor is pre-embedded in the tail-end bearing housing.

[0006] In the aforementioned compensation device for thermal expansion error of machine tool lead screw, both the drive end bearing housing and the tail end bearing housing are provided with mounting grooves. The front end temperature sensor is embedded in the mounting groove on the drive end bearing housing, and the rear end temperature sensor is embedded in the mounting groove on the tail end bearing housing.

[0007] Compared with existing technologies, the thermal expansion error compensation device for this machine tool's lead screw transmits temperature data collected by the front-end temperature sensor, rear-end temperature sensor, nut temperature sensor, and ambient temperature sensor in real time to the thermal expansion error calculation device. The thermal expansion error calculation device establishes real-time communication with the machine tool's CNC system through a standard data interface, uploads the calculated thermal expansion error value in real time, and integrates it into the position control loop. This allows for real-time correction and compensation of feed commands, effectively offsetting the positioning error caused by thermal expansion and ultimately significantly improving the machining accuracy of the equipment. The front-end and rear-end temperature sensors are pre-embedded, closer to the heat source, ensuring accurate temperature measurement, reliable compensation, and high precision. Furthermore, the pre-embedded installation reduces the complexity and risk of damage from external wiring, simplifying assembly. The independent thermal expansion error calculation device reduces dependence on the machine tool's CNC system, offering strong compatibility, high flexibility, and ease of modification and adaptation to different machine tool models. Attached Figure Description

[0008] Figure 1 This is a three-dimensional structural diagram of the compensation device for thermal expansion error of the lead screw of this machine tool.

[0009] Figure 2 This is a three-dimensional structural diagram of a portion of the compensation device for thermal expansion error of the lead screw of this machine tool.

[0010] In the diagram, 1 is the lead screw; 2 is the nut; 21 is the nut temperature sensor; 3 is the drive end bearing housing; 31 is the front end temperature sensor; 4 is the tail end bearing housing; 41 is the rear end temperature sensor; and 5 is the drive motor. Detailed Implementation

[0011] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0012] like Figure 1 and Figure 2As shown, the compensation device for thermal expansion error of the lead screw of this machine tool includes a drive-end bearing housing 3, a tail-end bearing housing 4, a lead screw 1, and a nut 2. One end of the lead screw 1 is located inside the tail-end bearing housing 4, and the other end of the lead screw 1 passes through the drive-end bearing housing 3 and is connected to the drive motor 5. The nut 2 is threaded onto the lead screw 1. A front-end temperature sensor 31 is provided inside the drive-end bearing housing 3, a rear-end temperature sensor 41 is provided on the tail-end bearing housing 4, and a nut temperature sensor 21 is provided on the nut 2. An ambient temperature sensor is also included to collect temperature data of the lead screw assembly itself and its surrounding environment in real time and accurately. It also includes a thermal expansion error calculation device and a machine tool CNC system. Temperature data collected by the front-end temperature sensor 31, the rear-end temperature sensor 41, the nut temperature sensor 21, and the ambient temperature sensor are transmitted to the thermal expansion error calculation device in real time. The thermal expansion error calculation device establishes real-time communication with the machine tool CNC system through a standard data interface, uploads the calculated thermal expansion error value ΔX in real time and integrates it into the position control loop, and corrects and compensates the feed command in real time, thereby effectively offsetting the positioning error caused by thermal expansion and ultimately significantly improving the machining accuracy of the equipment.

[0013] In the above technical solution: the front-end temperature sensor 31 is pre-embedded in the drive-end bearing housing 3, and the rear-end temperature sensor 41 is pre-embedded in the tail-end bearing housing 4, achieving accurate temperature acquisition. Specifically, both the drive-end bearing housing 3 and the tail-end bearing housing 4 have mounting grooves. The front-end temperature sensor 31 is embedded in the mounting groove on the drive-end bearing housing 3, and the rear-end temperature sensor 41 is embedded in the mounting groove on the tail-end bearing housing 4, completing the pre-embedded installation. The pre-embedded installation of the front-end temperature sensor 31 and the rear-end temperature sensor 41 brings them closer to the heat source, resulting in accurate temperature measurement, reliable compensation, and high precision. Simultaneously, the pre-embedded installation allows the front-end temperature sensor 31 and the rear-end temperature sensor 41 to be internally mounted, reducing the complexity and risk of damage from external wiring, and simplifying assembly.

[0014] In the above technical solution, the formula for calculating the thermal expansion error value ΔX used in the thermal expansion error calculation device is as follows:

[0015] in: α is the coefficient of thermal expansion, which depends on the material; the default value is... L represents the length of the lead screw (in meters). xm Location (unit: m) In this embodiment, the bearing deformation coefficient k1 is taken as 0.003. In this embodiment, the deformation coefficient of the disc spring, k2, is taken as 1233.7392. In this embodiment, the elastic modulus is taken as 210 GPa. A. Cross-sectional area of ​​the lead screw (unit: m²) 2 ) In the compensation device for thermal expansion error of the machine tool's lead screw, the temperature data collected by the front-end temperature sensor 31, the rear-end temperature sensor 41, the nut temperature sensor 21, and the ambient temperature sensor are transmitted in real time to the thermal expansion error calculation device. The thermal expansion error calculation device establishes real-time communication with the machine tool's CNC system through a standard data interface, uploads the calculated thermal expansion error value ΔX in real time, and integrates it into the position control loop. This allows for real-time correction and compensation of feed commands, effectively offsetting the positioning error caused by thermal expansion and ultimately significantly improving the machining accuracy of the equipment. The front-end temperature sensor 31 and the rear-end temperature sensor 41 are pre-embedded, closer to the heat source, ensuring accurate temperature measurement, reliable compensation, and high precision. The pre-embedded installation also allows for the built-in installation of the front-end temperature sensor 31 and the rear-end temperature sensor 41, reducing the complexity and risk of damage from external wiring and simplifying assembly. The independent thermal expansion error calculation device reduces dependence on the machine tool's CNC system, offering strong compatibility, high flexibility, and ease of modification and adaptation to different machine tool models.

[0016] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

[0017] Although this document frequently uses terms such as lead screw 1, nut 2, nut temperature sensor 21, drive end bearing housing 3, front end temperature sensor 31, tail end bearing housing 4, rear end temperature sensor 41, and drive motor 5, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

[0018] Contents not described in detail herein are existing technologies known to those skilled in the art. The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A compensation device for thermal expansion error of a machine tool lead screw, comprising a drive end bearing housing (3), a tail end bearing housing (4), a lead screw (1), and a nut (2), wherein one end of the lead screw (1) is located inside the tail end bearing housing (4), and the other end of the lead screw (1) passes through the drive end bearing housing (3) and is connected to a drive motor (5), and the nut (2) is threaded onto the lead screw (1), characterized in that... The drive end bearing housing (3) is provided with a front end temperature sensor (31), the tail end bearing housing (4) is provided with a rear end temperature sensor (41), and the nut (2) is provided with a nut temperature sensor (21). It also includes an ambient temperature sensor, a thermal expansion error calculation device and a machine tool CNC system. The temperature data collected by the front end temperature sensor (31), the rear end temperature sensor (41), the nut temperature sensor (21) and the ambient temperature sensor are transmitted to the thermal expansion error calculation device in real time. The thermal expansion error calculation device establishes real-time communication with the machine tool CNC system through a standard data interface.

2. The compensation device for thermal expansion error of a machine tool lead screw according to claim 1, characterized in that... The front-end temperature sensor (31) is pre-embedded in the drive end bearing housing (3), and the rear-end temperature sensor (41) is pre-embedded in the tail end bearing housing (4).

3. The compensation device for thermal expansion error of a machine tool lead screw according to claim 2, characterized in that... Both the drive end bearing housing (3) and the tail end bearing housing (4) have mounting grooves. The front end temperature sensor (31) is embedded in the mounting groove on the drive end bearing housing (3), and the rear end temperature sensor (41) is embedded in the mounting groove on the tail end bearing housing (4).

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