Machine tool positioning assembly and double-drive machine tool

Abstract

A machine tool positioning assembly comprises a machine tool base, a cross beam, a driving unit and a measuring assembly. The cross beam is connected to a pair of parallel sliding rails arranged on the machine tool base in a sliding mode. The two driving mechanisms are arranged at the two ends of the beam to drive the beam to slide along the sliding rails. The measuring assembly comprises a measuring head and a scale part, the measuring head is fixedly arranged in the middle of the cross beam span, and the scale part is fixedly arranged on the machine tool base and is opposite to the measuring head so that the measuring head can measure the relative position of the scale part. The machine tool positioning assembly can realize synchronism detection of a double-drive machine tool through a group of measurement assemblies, and is simple in structure, low in hardware cost and good in measurement accuracy. The utility model further provides a double-drive machine tool.

Description

Technical Field

[0001] The utility model belongs to the field of mechanical processing equipment, and specifically relates to a machine tool positioning component and a dual-drive machine tool. Background Art

[0002] High-precision CNC machine tools are an important foundation for achieving precision machining. In current conventional five-axis CNC machine tools, mechanical traditional systems such as roller screws or gear racks are increasingly unable to meet the requirements of precision machining due to problems such as unavoidable wear and tear, which results in the service life and machining accuracy of machine tools becoming increasingly difficult to meet the requirements of precision machining. Therefore, direct-drive machine tools using linear motors as power sources have been increasingly used in the design of five-axis CNC machine tools. Among them, dual-drive machine tools use two sets of parallel linear motors as power sources, which have higher power, a larger speed range, and higher reliability. They have been successfully applied in larger machine tools such as gantry machine tools. However, due to the use of two sets of linear motors for separate driving, the synchronization of the dual-drive motors is difficult to be effectively guaranteed, which restricts the technical promotion of dual-drive machine tools. Utility Model Content

[0003] The utility model aims to provide a machine tool positioning component to improve the accuracy of the synchronization measurement of the dual-drive motor. The utility model also provides a dual-drive machine tool.

[0004] According to an embodiment of one aspect of the utility model, a machine tool positioning assembly is provided, including a machine tool base, a beam, a drive unit and a measuring assembly. Among them, the machine tool base is provided with a pair of slide rails in parallel; the beam includes a sliding portion, which is provided at both ends of the beam and is in sliding connection with the slide rails; the drive unit includes two sets of driving mechanisms, which are respectively provided at both ends of the beam to drive the beam to slide along the extension direction of the slide rails; the measuring assembly includes a measuring head and a scale portion, the measuring head is fixedly provided at the middle position of the span of the beam, the scale portion is fixedly provided on the machine tool base and extends along the sliding direction of the beam, and the measuring head and the scale portion are arranged relative to each other to measure the relative position of the measuring head and the scale portion.

[0005] In the measuring assembly, the measuring head is set in the middle of the beam span and moves with the beam, and the scale part is fixedly installed on the machine tool base, so that the overall movement state of the beam can be determined by measuring the change in the relative position between the measuring head and the scale part during the movement of the beam; further, when there is an error in the synchronization of the driving mechanisms at both ends of the beam, the overall beam will be twisted relative to the extension direction of the slide rail, and then the measuring head and the scale part will rotate relative to each other, so the synchronization detection of the two driving mechanisms can be achieved through single-point measurement. The beam is supported on both sides during movement, so the deformation and error in the middle of the span during the movement of the beam are more stable. Setting the measuring head in the middle of the beam can achieve more accurate measurement.

[0006] Furthermore, in some embodiments, the length of the scale portion extending along the sliding direction of the beam is not less than the sliding stroke of the beam. The scale portion is provided with a sufficient length to achieve full-range measurement during the movement of the beam.

[0007] Furthermore, in some embodiments, the measuring head is configured as a non-contact measuring head. The non-contact measuring head has a simpler structure and avoids deformation errors caused by contact.

[0008] Furthermore, in some embodiments, the scale part is configured as a scale grating, and the measuring head is configured as a reading head. The combination of the scale grating and the reading head has a sensitive measurement accuracy and can accurately realize the synchronization detection of the double-side driving device of the crossbeam.

[0009] Furthermore, in some embodiments, the driving mechanism is configured as a linear motor. The linear motor has high power, can avoid the wear error caused by long-term operation of mechanical transmission mechanisms such as ball screws, and has higher precision.

[0010] Furthermore, the machine tool base is provided with a concave processing area, and the slide rail and the scale part are arranged outside the processing area and higher than the processing area. The measuring component is isolated from the processing area, which can avoid interference from debris or coolant generated during the operation of the machine tool.

[0011] Furthermore, the scale part is arranged in parallel with the slide rail, so as to avoid measurement errors caused by inconsistent heights.

[0012] According to another embodiment of the utility model, a machine tool is provided, including a spindle, the machine tool adopts the machine tool positioning assembly provided in any of the above embodiments, the spindle is installed on the crossbeam of the machine tool positioning assembly, and the spindle is driven by the crossbeam to move.

[0013] Furthermore, in some embodiments, the machine tool also includes a displacement module, the displacement module includes a lateral displacement module and a height displacement module, and the spindle is installed on the crossbeam through the displacement module.

[0014] Furthermore, in some embodiments, the machine tool also includes a processing table, which is configured as a cradle turntable and is disposed below the main spindle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of a machine tool in one embodiment;

[0016] Figure 2 A front view of a machine tool in one embodiment;

[0017] Figure 3Schematic diagram of the structure of a machine tool base in one embodiment.

[0018] The meaning of the numbers in the accompanying drawings: 10 - machine base; 11 - processing area; 12 - side wall; 13 - rear wall; 14 - slide rail; 20 - crossbeam; 21 - sliding part; 22 - linear motor; 23 - linear motor stator; 24 - linear motor mover; 31 - reading head; 32 - scale grating; 40 - spindle; 41 - lateral displacement module; 42 - height displacement module; 50 - processing table.

[0019] The purpose of the above drawings is to explain the utility model in detail so that those skilled in the art can understand the technical concept of the utility model, but it is not intended to limit the utility model. For the sake of simplicity, the above drawings only schematically illustrate the structure related to the technical features of the utility model, and do not strictly draw the complete structure and all details according to the actual proportion. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The phrase appearing in various locations in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments herein may be combined with other embodiments without causing structural conflicts.

[0022] In the description of this article, unless otherwise clearly specified and limited, the technical terms "installed", "connected", "connected" and the like should be understood in a broad sense, which can be a movable connection, a fixed connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0023] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to have a specific orientation, be installed or operate in a specific orientation, and should not be construed as a limitation on the embodiments in this document.

[0024] In the description of this article, the terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary and secondary relationship of the described technical features. In the description of this article, the meaning of "plurality" is at least two.

[0025] Dual-drive machine tools can provide higher drive power and speed range, but if a special measuring and positioning device is not set up, the synchronization of the dual-drive motor is difficult to ensure. If there is an error in the synchronization of both sides, the machining accuracy of the machine tool will be significantly reduced. At present, some technical solutions adopt a dual-drive dual-measurement design, that is, measuring devices are set up on both sides to control the synchronization of the dual-drive motor. However, in this technical solution, two sets of measuring devices need to be set up and the sensors need to be calibrated separately to achieve precision matching. The hardware cost is high and the calibration process is complicated; other technical solutions adopt a dual-drive single-measurement design, that is, the measuring device is set up only on one side of the dual-drive motor. Although this reduces the hardware cost and calibration workload, it leads to a decrease in measurement accuracy and is difficult to meet the requirements of precision machining.

[0026] In order to solve the above problems, the embodiment of the utility model provides a machine tool, which uses a single set of measuring devices to accurately measure the synchronization of dual-drive motors and improve the control accuracy of the machine tool. Figure 1 As shown, it includes a positioning assembly, which includes a machine tool base 10, a crossbeam 20, two groups of linear motors 22 as drive units, and a measuring assembly.

[0027] Combination Figure 3 A pair of slide rails 14 are arranged in parallel on the machine tool base 10; Figure 2 , sliding parts 21 are provided at both ends of the cross beam 20, and the sliding parts 21 are matched with the slide rail 14 to form a sliding connection, so that the cross beam 20 can slide along the extension direction of the slide rail 14. Figure 2 As shown, the linear motor 22 includes a linear motor stator 23 fixed to the machine tool base 10 and a linear motor mover 24 fixed to the crossbeam 20, and the linear motors 22 on both sides jointly provide a driving force for the crossbeam 20 to slide along the slide rail 14. Among them, the linear motor stators 23 are arranged vertically, so that the magnetic force between the linear motor stators 23 and the linear motor movers 24 is in a horizontal direction, and the linear motor stators 23 on both sides are arranged relative to each other (that is, the two linear motor stators 23 are arranged on the outside, and the two linear motor movers 24 are arranged on the inside), on the one hand, to avoid the magnetic force from increasing the load of the slide rail 14 in the vertical direction, and on the other hand, to make the magnetic forces generated by the linear motors 22 on both sides offset each other. In other embodiments, the linear motor stators 23 on both sides can also be arranged on the inside and the linear motor movers 24 on the outside, which can also achieve the effect of offsetting the magnetic forces.

[0028] The measuring assembly includes a measuring head configured as a reading head 31 and a scale part configured as a scale grating 32. The reading head 31 is arranged on the crossbeam 20, and the scale grating 32 is arranged on the machine tool base. The reading head 31 is fixedly arranged at the middle of the span of the crossbeam 20 (usually, the difference in distance from the slide rails 14 at both ends does not exceed 1mm). The scale grating 32 is arranged opposite to the reading head 31. Figure 3, the scale grating 32 extends along the sliding defense line of the beam, so that the reading head 31 can measure the relative position between itself and the scale grating 32 during the sliding process of the beam 20. Specifically, the meaning of the relative position can include the displacement distance of the reading head 31 relative to the scale grating 32 or the rotation angle of the reading head 31 relative to the scale grating 32. Here, the relatively set indicator scale grating 32 is set in the measurement area of ​​the reading head 31, so that the reading head 31 can measure the relative position between itself and the scale grating 32. Since both ends of the beam 20 are slidably connected to the slide rail 14 through the sliding part 21, once the displacement of both sides of the beam 20 is not synchronized during the movement of the beam 20, the middle position of the span of the beam 20 is the area with the most stable deformation and displacement. The reading head 31 is set in the middle of the span of the beam 20 to achieve the most accurate measurement. It should be understood that the middle position of the span of the beam 20 does not refer to the midpoint of the overall length of the beam 20, but rather the middle position with the two side rails 14 as the measuring endpoints. In some embodiments, due to differences in structural design schemes, the lengths of the beam 20 extending outward relative to the two side rails 14 are not equal.

[0029] In a preferred embodiment, the length of the scale grating 32 extending along the sliding direction of the beam 20 is not less than the sliding stroke of the beam 20, so that the reading head 31 can measure the scale grating 32 at any position during the sliding process of the beam 20. Figure 3 It should be understood that, since the mechanical structure of the machine tool occupies a certain space, in a preferred embodiment, the actual length of the scale grating 32 does not necessarily correspond to the overall length of the slide rail 14 , but should correspond to the sliding stroke of the beam 20 .

[0030] In other embodiments, the reading head 31 and the scale grating 32 may also be replaced by other devices with displacement measurement functions such as capacitive displacement sensors or angle sensors. In some embodiments, the measuring assembly may also use contact sensors such as differential transformers for measurement, but the contact sensors need to consider the actual structural limitations of the machine tool and the deformation of the sensor contact area generated during the sliding of the beam 20.

[0031] like Figure 3 As shown, a concave processing area 11 is formed on one side of the machine tool base 10, combined with Figure 1The processing area 11 is used to install a cradle-type processing table 50 and provide a working space for the machine tool spindle 40 to perform mechanical processing. Side walls 12 are respectively provided on both sides of the processing area 11, and a rear wall 13 is provided between the two side walls 12. The side walls 12 and the rear wall 13 are raised relative to the processing area 11. The slide rails 14 are respectively provided on the top of the two side walls 12, and the scale grating 32 is provided in the middle section of the rear wall 13 and extends parallel to the slide rails 14. Among them, the concave setting of the processing area 11 physically isolates the working area of ​​the mechanical processing from the working area of ​​the drive unit and the measuring component, thereby avoiding contamination caused by debris and splashes generated during the mechanical processing process. The extension of the scale grating 32 parallel to the slide rail 14 can keep the vertical distance between the reading head 31 and the scale grating 32 consistent during the sliding process of the crossbeam 20, thereby avoiding measurement errors caused by the inclination of the scale grating 32.

[0032] like Figure 1 As shown, the machine tool spindle 40 is installed on the crossbeam 20 through the machine tool positioning assembly, and the sliding of the crossbeam 20 can provide the machine tool spindle with the freedom to move along the length direction of the slide rail 14. The machine tool positioning assembly specifically includes a lateral displacement module 41 and a height displacement module 42. Among them, the lateral displacement module 41 is arranged along the length direction of the crossbeam 20, and provides the spindle 40 with the freedom to move along the length direction of the crossbeam 20; the height displacement module 42 is connected to the lateral displacement module 41, and provides the spindle 40 with the freedom to move in the vertical height direction. In this way, the crossbeam 20, the lateral displacement module 41 and the height displacement module 42 jointly provide the spindle 40 with the translational freedom in the three directions of x, y and z.

[0033] The processing table 50 is arranged in the processing area 11 below the spindle 40, and is used to carry the workpiece to be processed. In a preferred embodiment, the processing table 50 is configured as a cradle-type processing table, which can provide the workpiece to be processed with the degrees of freedom of swinging and rotating.

[0034] In a preferred embodiment, Figures 1 to 3 The working process of the machine tool shown is as follows.

[0035] The workpiece to be processed is fixed on the workbench 50, the processing parameters are input, and the machine tool is instructed to start working.

[0036] The two sets of linear motors 22 drive the crossbeam 20 to slide. During the sliding of the crossbeam 20, the reading head 31 measures the distance between the reading head 31 and the scale grating 32 in real time to determine whether the movement strokes of the linear motors 22 on both sides are synchronized.

[0037] At a certain moment, when the displacement stroke read by the reading head 31 is not equal to the displacement stroke set at that moment according to the program, or the relative angle between the reading head 31 and the scale grating 32 is offset, it means that the linear motors 22 on both sides of the beam 20 drive the displacement of the beam 20 to form an asynchronism. It is easy to understand that the reading head 31 set in the middle of the beam 20 should reflect the average value of the displacement strokes at both ends of the beam 20, and when the displacement strokes at both ends of the beam 20 are not equal, the beam 20 will deflect relative to the sliding direction. At this time, it is necessary to adjust and calibrate the linear motors 22 on both sides of the beam 20 to eliminate the stroke error of the linear motor 22, so as to avoid the machining accuracy of the machine tool being affected by the asynchronism of the linear motor 22.

[0038] When the travel data measured by the reading head 31 is consistent with the processing program setting and there is no angle deviation, it means that the machine tool is working normally. By adjusting the parameters of the beam 20, the lateral displacement module 41, the height displacement module 42 and the processing table 50, the five-axis processing of the workpiece to be processed is completed.

[0039] The purpose of the above embodiments is to further explain the present invention in detail in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, the optimization or equivalent replacement of the structure of the parts involved, and the combination of the implementation methods in different embodiments without conflict of structure and principle, all fall within the protection scope of the present invention.

Claims

1. A machine tool positioning assembly, characterized in that: include Machine base, crossbeam, drive unit and measuring components, of which: The machine tool base is provided with a pair of slide rails in parallel; The crossbeam comprises a sliding portion, which is arranged at both ends of the crossbeam and is slidably connected to the slide rail; The driving unit comprises two sets of driving mechanisms, which are respectively arranged at two ends of the crossbeam to drive the crossbeam to slide along the extension direction of the slide rail; The measuring assembly includes a measuring head and a ruler portion, wherein the measuring head is fixedly arranged at the middle position of the span of the beam, the ruler portion is fixedly arranged on the machine tool base and extends along the sliding direction of the beam, and the measuring head and the ruler portion are arranged relative to each other to measure the relative position of the measuring head and the ruler portion.

2. The machine tool positioning assembly according to claim 1, characterized in that: The length of the scale portion extending along the sliding direction of the beam is not less than the sliding stroke of the beam.

3. The machine tool positioning assembly according to claim 1 or 2, characterized in that: The measuring head is configured as a non-contact measuring head.

4. The machine tool positioning assembly according to claim 3, characterized in that: The scale part is configured as a scale grating, and the measuring head is configured as a reading head.

5. The machine tool positioning assembly according to claim 1 or 2, characterized in that: The driving mechanism is configured as a linear motor.

6. The machine tool positioning assembly according to claim 1 or 2, characterized in that: The machine tool seat is provided with a concave processing area, and the slide rail and the scale part are arranged outside the processing area and higher than the processing area.

7. The machine tool positioning assembly according to claim 1 or 2, characterized in that: The scale portion is arranged parallel to the slide rail.

8. A dual-drive machine tool, comprising a spindle, characterized in that: The machine tool comprises a machine tool positioning assembly as claimed in any one of claims 1 to 7, and the spindle is mounted on the crossbeam of the machine tool positioning assembly.

9. The dual-drive machine tool according to claim 8, characterized in that: The machine tool further comprises a displacement module, wherein the displacement module comprises a lateral displacement module and a height displacement module, and the spindle is mounted on the crossbeam via the displacement module.

10. The dual-drive machine tool according to claim 8 or 9, characterized in that: Also included is a processing table configured as a cradle turntable and disposed below the main shaft.

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