Center pillar vertical turning and milling composite machine tool suitable for inner hole machining

Abstract

The invention discloses a center pillar vertical turning and milling composite machine tool suitable for inner hole machining, and relates to the technical field of numerical control machine tool equipment, the center pillar vertical turning and milling composite machine tool comprises a base, a rotary table body is rotatably mounted at the top of the base, and a composite guide rail is arranged between the rotary table body and the base; the rotary table body is fixedly provided with a driving gear ring, and the driving gear ring is in transmission connection with an even number of driving gears; each driving gear is in transmission connection with a motor through a speed reducing mechanism; a stand column is further arranged on the base, and a tool feeding mechanism is arranged on the stand column. Therefore, the stand column is additionally arranged on the base, and the cutter feeding mechanism is arranged, so that the inner hole of the large-sized workpiece is machined, the purchase cost of large-sized equipment is reduced, accumulation of original errors is reduced, and higher-precision machining of the large-sized workpiece is achieved.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool technology, specifically to a vertical turning and milling composite machine tool with a central column suitable for internal hole machining. Background Technology

[0002] To adapt to the development of large-scale mechanical equipment, the development trend of CNC machine tools and machine tool rotary tables is also towards large and heavy-duty designs. For complex parts in certain specific fields, such as the cylinders of large steam turbines used in thermal power generation and nuclear power plants, due to their large size (greater than 8M), a generally economical machining method is to first machine one end face and inner surface of the cylinder, then turn the workpiece around and machine the other end face and inner surface, and finally use a large boring machine for precision boring to ensure machining accuracy and coaxiality. In existing technology, to achieve the machining of ultra-large internal holes, there is a publication with publication number CN207189187U, entitled "An Adjustable Support Device for Improving the Stability of Deep Hole Machining." This document describes a method that adjusts the longitudinal movement of support one, support two, and support three by setting a longitudinal fine-tuning mechanism to ensure stability during deep hole machining.

[0003] The following problems may also occur during the above processing:

[0004] 1. Due to the limited size of the workpiece and processing equipment, in addition to using a variety of processing tools, multiple clamping is required. Each clamping and positioning will have installation errors. The accumulation of multiple installation errors will produce large processing errors. Moreover, the entire installation process is not only extremely cumbersome, but also affects the processing speed and processing quality of the workpiece.

[0005] 2. Although the boring bar of a boring machine has high rigidity, the hole to be machined is relatively deep, especially in horizontal boring machines. After the boring bar extends a long distance at high speed, it will sag due to the influence of gravity and centrifugal force. This results in a certain taper on the inner wall of the machined hole, which affects the subsequent assembly of parts. Even if, as mentioned in the above patent documents, some manufacturers compensate for the sag by adding boring bar support or by using program algorithms, the machining accuracy is still difficult to achieve the design accuracy.

[0006] To overcome the inherent defects of boring machines, some manufacturers use gantry-type composite machine tools. Gantry-type composite machine tools are large in size and span, and can process almost all types of workpieces. However, ultra-large gantry-type composite machine tools that can process cylinders generally can only be imported. They are extremely large, have extremely high purchase prices (generally exceeding ten million), and have high subsequent installation and maintenance costs. They are mostly used in the military industry. Summary of the Invention

[0007] To overcome the above-mentioned defects, the purpose of this invention is to provide a column-type vertical turning and milling composite machine tool suitable for internal hole machining. By adding a column to the base and setting a tool feed mechanism, it can machine the internal holes of large workpieces, reduce the procurement cost of large equipment, reduce the accumulation of original errors, and achieve higher precision machining of large workpieces.

[0008] To achieve the above objectives, the present invention provides a column-type vertical turning and milling composite machine tool suitable for internal hole machining, comprising a base, a rotary table body rotatably mounted on the top of the base, and a composite guide rail between the rotary table body and the base; a drive gear ring fixedly mounted on the rotary table body, the drive gear ring being drivenly connected to an even number of drive gears; each drive gear being drivenly connected to a motor through a reduction mechanism; a column is also provided on the base, the column being coaxially arranged with the axis of the rotary table body; and a tool feed mechanism is provided on the column.

[0009] Preferably, the tool feed mechanism includes a longitudinal feed unit and a transverse feed unit.

[0010] Preferably, the longitudinal feed unit includes a lifting motor and a lifting arm. The lifting motor is located at the top of the column, and the lifting arm is slidably connected to the column. The lifting arm is driven by the lifting motor through a lifting screw. The transverse feed unit is disposed on the lifting arm and includes a feed motor and a feed screw. The machining tool is any one of a lathe tool, an electric tool holder, or a milling power head. The tool holder of the machining tool is driven by the feed screw.

[0011] Preferably, the composite guide rail includes a hydrostatic guide rail and a rolling bearing. The hydrostatic guide rail is disposed between a pair of upper and lower surfaces of the rotary table body and the base. The hydrostatic guide rail is located on the outside and close to the drive gear. The rolling bearing is disposed between a pair of inner and outer peripheral surfaces of the rotary table body and the base, and the outer peripheral surface of the column abuts against the inner ring of the rolling bearing.

[0012] Preferably, the rolling bearing is a crossed roller bearing, and the hydrostatic guide rail is a circumferentially distributed hydrostatic cavity sliding track.

[0013] Preferably, the deceleration mechanism is located on the inner side and is a planetary deceleration mechanism.

[0014] Preferably, the planetary reduction mechanism includes a housing, a sun gear, a planetary carrier, planetary gears, and a planetary carrier output shaft. The housing is fixedly connected to the base, and the housing is provided with an internal gear ring. The sun gear is driven by the motor shaft, and the planetary gears are rotatably mounted on the planetary carrier. The sun gear meshes with the internal gear ring through the planetary gears. The planetary carrier output shaft is fixedly connected to the planetary carrier and is driven by the drive gear.

[0015] Preferably, a two-stage reduction gear is provided between the sun gear and the motor.

[0016] Preferably, the secondary reduction mechanism includes a housing, in which a main power input shaft, an intermediate shaft, and a main power output shaft are rotatably mounted. The main power output shaft is coaxially arranged with the main power input shaft, and the output end of the main power output shaft is connected to the sun gear drive.

[0017] The main power input shaft is connected to the motor drive. The main power input shaft is provided with a main power gear. The intermediate shaft is provided with an intermediate shaft pinion and an intermediate shaft large gear. The main power output shaft is slidably provided with a two-axis transmission gear. The two-axis transmission gear can selectively mesh with the main power gear or the intermediate shaft pinion.

[0018] Preferably, the reduction mechanism is located on the outside and is a gear reducer. The power output shaft of the gear reducer is connected to the drive gear through a bevel gear pair.

[0019] Preferably, a rotation speed measuring device is provided between the rotary table body and the base, and the rotation speed measuring device is a circular magnetic encoder.

[0020] Preferably, the circular magnetic encoder includes at least one circular magnetic grid, each circular magnetic grid includes at least two reading heads, the reading heads are fixedly connected to the base by a reading head bracket, the circular magnetic grid corresponds to the height of the reading head and is circumferentially arranged on the side of the rotary table body.

[0021] The beneficial technical effects achieved by the present invention after adopting the above technical solution are as follows:

[0022] 1. A column, collinear with the axis of the rotary table body, is installed on the base, and a tool feed mechanism for machining the workpiece is mounted on the column. The column remains stationary. Once the workpiece is fixed to the rotary table body by chucks, the tool feed mechanism on the column can machine the inner hole of the workpiece as the rotary table body rotates at high speed. When the tool feed mechanism is a turning tool assembly, it can achieve turning of the inner hole of large workpieces, with significantly higher machining accuracy than boring. Moreover, the machining distance and range are only limited by the height of the column, allowing for the machining of even the inner holes of ultra-long and ultra-large workpieces (such as large steam turbine casings). Throughout the machining process, because it involves one clamping and one positioning, it greatly reduces the initial installation error caused by multiple workpiece movements. This not only shortens the transfer time but also ensures machining accuracy by reducing clamping time, making it particularly suitable for machining steam turbine casings and wind turbine casings. Furthermore, the machined workpiece has high coaxiality, which is beneficial for subsequent assembly.

[0023] 2. By replacing the traditional roller bearings or hydrostatic guideways in machine tool rotary tables with a combination of relatively small-diameter crossed roller bearings and large-diameter, wide-surface hydrostatic guideways, heavy-duty requirements are met, and the problem of rotational eccentricity caused by unstable hydraulic pressure during hydrostatic guideway rotation is overcome. Simultaneously, the low coefficient of friction and good vibration absorption performance of hydrostatic guideways meet the high-speed rotation requirements of CNC machine tool rotary tables. Throughout the machining process, the movement is smoother and machining accuracy is more easily maintained, making it particularly suitable for unmanned CNC machine tools. Both crossed roller bearings and hydrostatic guideways can be purchased according to specific models, resulting in lower installation and maintenance costs.

[0024] 3. Utilizing the principle of backlash elimination with dual motors, multiple rotary drive units are set up, working in conjunction with several motors. This ensures that during the operation of the rotary table, at least one drive gear generates tension with the rotary table's drive ring gear, guaranteeing that the motor output torque will never be zero simultaneously. Under this torque, motion backlash is impossible, thus ensuring output stability. In particular, fixing the motors and reduction mechanisms to the base creates an integrated backlash-free transmission structure composed of several motors, planetary reduction mechanisms, drive gears, and a large ring gear. This direct-drive power transmission unit offers advantages such as a short transmission chain, high output rigidity, energy saving, and high rotational accuracy.

[0025] 4. Because a circular magnetic encoder is installed between the rotary table body and the base, multiple circular magnetic grids are arranged circumferentially on the side of the rotary table body, and the data of the circular magnetic grids is received by the reading head. This arrangement makes full use of the circumference of the entire rotary table body. Compared with the traditional circular magnetic encoder, the detection accuracy is higher, especially ensuring the indexing accuracy of large rotary table bodies. It is also easier to install and maintain, and the signal reception is more stable. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the installation structure in which the motor and planetary reduction gear are placed inside the base;

[0027] Figure 2 This is a schematic diagram of the installation structure of the reduction mechanism using a single-stage gear reducer direct drive;

[0028] Figure 3 This is a schematic diagram of the installation structure of the reduction mechanism using a two-stage gear reducer direct drive;

[0029] Figure 4 This is a schematic diagram of the explosion state of the planetary deceleration mechanism in this invention;

[0030] Figure 5 This is an internal schematic diagram of the two-stage reduction mechanism in this invention;

[0031] Figure 6 This is a reference diagram showing the usage state of the present invention combined with a composite drilling machine;

[0032] Figure 7 This is a reference diagram showing the combination of the present invention with the moving column vertical carriage and the position of the circular magnetic grating encoder;

[0033] In the diagram,

[0034] 1. Base; 11. Hydrostatic guide rail; 12. Crossed roller bearing; 13. Bevel gear pair; 14. Gear reducer; 15. Column; 16. Reading head bracket; 17. Reading head;

[0035] 2. Rotary table body; 21. Drive gear ring; 22. Circular magnetic encoder; 221. Circular magnetic encoder; 23. Drive gear;

[0036] 3. Planetary reduction mechanism; 31. Motor shaft; 311. Sun gear; 32. Planetary support; 321. Planetary support output shaft; 322. Planetary gear; 33. Intermediate shaft; 331. Intermediate shaft pinion; 332. Intermediate shaft gear; 34. Main power output shaft; 341. Secondary shaft transmission gear; 35. Housing; 351. Internal gear ring; 36. Housing; 37. Main power input shaft; 371. Main power gear;

[0037] 4. Electric motor;

[0038] 5. Tool feed mechanism; 51. Lifting motor; 52. Lifting arm; 521. Feed motor; 522. Feed screw; 53. Lifting screw

[0039] 6. Workpiece;

[0040] 7. Peripheral machining unit. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the invention and are not intended to limit the invention.

[0042] See Figures 1-7 This invention provides a central column vertical milling and turning composite machine tool suitable for internal hole machining, including a base 1, a rotary table body 2 rotatably mounted on the top of the base 1, and a composite guide rail between the rotary table body 2 and the base 1; a drive gear ring 21 is fixedly mounted on the rotary table body 2, and the drive gear ring 21 is driven by an even number of drive gears 23; each drive gear 23 is driven by a motor 4 through a reduction mechanism; a column 15 is also provided on the base 1, and the column 15 is coaxially arranged with the axis of the rotary table body 2; a tool feed mechanism is provided on the column 15, and the column 15 has high rigidity to support the tool feed mechanism 5, realizing the machining of the internal hole of the workpiece 6. The base 1 is used to support the rotary table body 2, and the coaxially arranged column 15 is installed in the middle of the base 1 to ensure the machining accuracy during rotary machining. The column 15 has high rigidity, and its diameter should be adapted to the workpiece 6 to be machined.

[0043] In this invention, direct-drive motors are used throughout, meaning the motor 4 is directly connected to the drive gear 23. The entire motor 4 can be housed inside the base 1, and the rotational speed of the rotary table body 2 is controlled by controlling the rotational speed of the motor 4. However, housing the motor 4 internally makes the installation process relatively complex and increases processing and maintenance costs. Compared to... Figure 1 The motor 4 can be installed vertically in the vertical carriage, or horizontally in the vertical carriage. See [reference needed]. Figure 2 and Figure 3 In this invention, the power output direction is adjusted using a bevel gear pair 13. This is achieved by installing the bevel gear pair 13 in an angle reducer, changing the angle of power transmission, while still maintaining the power transmission using direct-drive motor technology. External installation is the most common method, offering greater convenience for installation and maintenance. Based on the mechanical principles of backlash elimination with dual motors, this invention typically uses an even number of drive gears 23 meshing with the drive gear ring 21, preferably 2, 4, 6, or 8 drive gears 23.

[0044] The tool feed mechanism 5 includes a longitudinal feed unit and a transverse feed unit. For machining straight holes, only the longitudinal feed unit can be used. However, since most parts are complex, the longitudinal and transverse feed units are generally used together to machine the workpiece 6. The longitudinal feed unit includes a lifting motor 51 and a lifting arm 52. The lifting motor 51 is located at the top of the column 15, and the lifting arm 52 is slidably connected to the column 15. The lifting arm 52 is connected to the lifting motor 51 via a lifting screw 53. The transverse feed unit is located on the lifting arm 52 and includes a feed motor 521 and a feed screw 522. Taking a turning tool as an example, the tool holder is connected to the feed screw 522, and under the power drive of the lifting motor 51 and the feed motor 521, the tool in the tool feed mechanism on the lifting arm 52 performs turning on the workpiece 6. The tool feed mechanism 5 is a mature existing technology with many applications in the machine tool field. It mainly drives the feed motion of the tool holder through a screw. It can be purchased directly according to the required size and model. In addition to using a lathe tool, an electric tool post or milling power head can also be used. By changing different milling power heads, different machining processes can be achieved.

[0045] The composite guide rail of this invention includes a hydrostatic guide rail 11 and a rolling bearing. The hydrostatic guide rail 11 is disposed between a pair of upper and lower surfaces of the rotary table body 2 and the base 1, located externally and close to the drive gear 23. The rolling bearing is disposed between a pair of inner and outer circumferential surfaces of the rotary table body 2 and the base 1, with the outer circumferential surface of the column 15 abutting against the inner ring of the rolling bearing. The rolling bearing of this invention is a crossed roller bearing 12, and the hydrostatic guide rail 11 is a circumferentially distributed hydrostatic cavity sliding track. To meet the usage requirements of ultra-large rotary tables, some manufacturers use a combination of hydrostatic guide rail 11 and cylindrical roller bearings, utilizing a hydraulic system to achieve heavy loads, and adjusting the oil supply pressure according to the weight of the workpiece 6. See patent publication number CN110091186B, entitled: An Embedded Direct Drive Rotary Table Using Hydrostatic Guide Rails. This patent document contains a more detailed description. The hydrostatic guide rail 11 is a mature existing technology, and its oil film can greatly reduce friction. The use of rigid rolling bearings ensures minimal errors during operation. A hydrostatic guide rail 11 and rolling bearings are respectively installed between the rotary table body 2 and the base 1. The hydrostatic guide rail 11 is located on the outside between a pair of upper and lower surfaces of the rotary table body 2 and the base 1, while the rolling bearings are located between a pair of inner and outer circumferential surfaces of the rotary table body 2 and the base 1. Utilizing the heavy-duty characteristics of the hydrostatic guide rail 11, combined with the rigidity of the crossed roller bearings 12, the rotary table body 2 is suitable for heavy loads while maintaining good machining accuracy.

[0046] A speed measuring device is installed between the rotary table body 2 and the base 1. The speed measuring device is generally purchased directly according to the model, and there are mainly two types. One is a circular magnetic encoder 22 (see Figure 5The circular magnetic encoder 22 is generally a disc-shaped device, located at the bottom of the drive gear 23. It measures the rotational speed of the drive gear 23, and then uses the system's algorithm to determine the rotational speed of the rotary table body 2. However, its accuracy is limited by the size of the disc. Another speed measurement device uses a strip-shaped circular magnetic encoder 22 (see...). Figure 6 To ensure uninterrupted signal transmission, two circular magnetic gratings 221 are typically installed. Each circular magnetic grating 221 is equipped with two reading heads 17 for receiving data. The circular magnetic gratings 221 are circumferentially and fixedly installed on the side of the rotary table body 2. The reading heads 17 are fixedly connected to the base 1 via reading head brackets 16. The distance between the two is generally 2-5mm. This is used to collect and feedback the rotation speed signal. Since gaps may easily appear between the circular magnetic gratings 221 after they are fixed, at least two reading heads 17 are typically installed to achieve the adjustment of the rotation speed and precise indexing of the rotary table body 2. Figure 6 The image shows only the mounting positions of one circular magnetic grating 221 and two reading heads 17.

[0047] The reduction mechanism of this invention is a planetary reduction mechanism 3. The planetary reduction mechanism 3 is a relatively mature existing technology, and using it can achieve smooth output power. When multiple drive gears 23 drive the same gear ring, not only can transmission backlash be eliminated, but also a larger output torque can be obtained, making it suitable for large rotary table bodies 2. The reduction mechanism of this invention can also be replaced by a single gear, which is cheaper, but the precision is relatively lower, and it is only suitable for rough machining of some workpieces. Because the planetary reduction mechanism 3 has a compact structure, a wider reduction ratio range, and high precision, it is preferred, as it can further shorten the transmission chain and improve the direct drive effect.

[0048] The planetary reduction mechanism 3 of the present invention includes a housing 35, a sun gear 311, a planetary carrier 32, planetary gears 322, and a planetary carrier output shaft 321. The housing 35 is fixedly connected to the base 1. The housing 35 is provided with an internal gear ring 351. The sun gear 311 is drivenly connected to the motor shaft 31. The planetary gears 322 are rotatably mounted on the planetary carrier 32, and the sun gear 311 meshes with the internal gear ring 351 through the planetary gears 322. The planetary carrier output shaft 321 is fixedly connected to the planetary carrier 32, or it can be integrally formed. The planetary carrier output shaft 321 is fixedly connected to the drive gear 23. The sun gear 311 is directly connected to the motor shaft 31 of the motor 4. Multiple planetary gears 322 rotate around the sun gear 311 and transmit power to the planetary carrier output shaft 321 through the planetary carrier 32. The drive gear 23 is drivenly connected to the drive gear ring 21, thereby transmitting the power of the motor 4 to the drive gear ring 21. The drive gear ring 21 can be an internal gear ring 351 or an external gear ring. Both types can use a planetary reduction mechanism 3 to achieve power transmission.

[0049] See Figure 2In this invention, a two-stage reduction mechanism is provided between the sun gear 311 and the motor 4. The two-stage reduction mechanism includes a housing 36, within which a main force input shaft 37, an intermediate shaft 33, and a main force output shaft 34 are rotatably mounted. The main force output shaft 34 is coaxially arranged with the main force input shaft 37, and its output end is drive-connected to the sun gear 311. The main force input shaft 37 is drive-connected to the motor shaft 31. The main force input shaft 37 is equipped with a main force gear 371. The intermediate shaft 33 is equipped with an intermediate shaft pinion 331 and an intermediate shaft large gear 332. A second-axis transmission gear 341 is slidably arranged on the main force output shaft 34, and the second-axis transmission gear 341 can selectively mesh with either the main force gear 371 or the intermediate shaft pinion 331. The two-stage reduction mechanism is based on a single-stage planetary reduction gear, with a gearbox added to the output end of the motor 4 to achieve gear shifting, thereby increasing the output torque. A dual-shaft transmission gear 341 slides on the main power output shaft 34. The dual-shaft transmission gear 341 is typically connected to a shifting mechanism. It can be directly connected to the main power input shaft 37, or the input speed of the main power input shaft 37 can be reduced by a gearbox, passing through a small gear 331 and a large gear 332 on an intermediate shaft before being output to the sun gear 311. There can be multiple intermediate shafts 33 in the housing 36, but two are generally preferred and symmetrically installed. The module of the small gear within the housing 36 is generally small; multi-gear drive is used to output greater torque.

[0050] The reduction mechanism of this invention is located on the outside and is a gear reducer 14. The power output shaft of the gear reducer 14 is connected to the drive gear 23 via a bevel gear pair 13. The gear reducer 14 is existing technology, and the transmission ratio can be set according to the transmission requirements. Figure 3 The one shown is a single-stage gearbox, but a two-stage or three-stage gearbox can also be selected.

[0051] Because the turbine casing involves numerous machining processes, this invention generally requires the use of an external machining unit 7. The external machining unit 7 can be any one of a moving-column vertical lathe, a fixed-column vertical lathe, a composite drilling machine, or a gantry milling and turning machine. The external machining unit 7 is primarily used for machining the outer surface of the workpiece, such as turning, milling, grinding, and drilling, aiming to complete the machining of the entire workpiece 6 in a single setup whenever possible.

Claims

1. A vertical turning and milling machine tool with a central column suitable for internal hole machining, comprising: The base is characterized in that a rotary table body is rotatably mounted on the top of the base, and a composite guide rail is provided between the rotary table body and the base; The rotary table body is fixedly provided with a drive gear ring, and the drive gear ring is driven by an even number of drive gears; each of the drive gears is driven by a motor through a reduction mechanism. The base is also provided with a column, and the column is coaxial with the axis of the rotary table body; the column is provided with a tool feed mechanism.

2. The vertical turning and milling compound machine tool with a central column according to claim 1, characterized in that, The tool feed mechanism includes a longitudinal feed unit and a transverse feed unit.

3. The vertical turning and milling compound machine tool with a central column according to claim 2, characterized in that, The longitudinal feed unit includes a lifting motor and a lifting arm. The lifting motor is located at the top of the column, and the lifting arm is slidably connected to the column. The lifting arm is connected to the lifting motor via a lifting screw. The transverse feed unit is located on the lifting arm and includes a feed motor and a feed screw. The machining tool is any one of a lathe tool, an electric tool holder, or a milling power head. The tool holder of the machining tool is connected to the feed screw.

4. The vertical turning and milling compound machine tool with a central column according to claim 1, characterized in that, The composite guide rail includes a hydrostatic guide rail and a rolling bearing. The hydrostatic guide rail is disposed between a pair of upper and lower surfaces of the rotary table body and the base. The hydrostatic guide rail is located on the outside and close to the drive gear. The rolling bearing is disposed between a pair of inner and outer circumferential surfaces of the rotary table body and the base, and the outer circumferential surface of the column abuts against the inner ring of the rolling bearing.

5. The vertical turning and milling compound machine tool with a central column according to claim 4, characterized in that, The rolling bearing is a crossed roller bearing, and the hydrostatic guide rail is a circumferentially distributed hydrostatic cavity sliding track.

6. The vertical turning and milling compound machine tool with a central column according to claim 1, characterized in that, The deceleration mechanism is located on the inner side and is a planetary deceleration mechanism.

7. The vertical turning and milling compound machine tool with a central column according to claim 6, characterized in that, The planetary reduction mechanism includes a housing, a sun gear, a planetary carrier, planetary gears, and a planetary carrier output shaft. The housing is fixedly connected to the base. The housing is provided with an internal gear ring. The sun gear is driven by the motor shaft. The planetary gears are rotatably mounted on the planetary carrier. The sun gear meshes with the internal gear ring through the planetary gears. The planetary carrier output shaft is fixedly connected to the planetary carrier and is driven by the drive gear.

8. The vertical turning and milling compound machine tool with a central column according to claim 7, characterized in that, A two-stage reduction mechanism is provided between the sun gear and the motor; The secondary reduction mechanism includes a housing, in which a main force input shaft, an intermediate shaft, and a main force output shaft are rotatably mounted. The main force output shaft is coaxially arranged with the main force input shaft, and the output end of the main force output shaft is connected to the sun gear drive. The main power input shaft is connected to the motor drive. The main power input shaft is provided with a main power gear. The intermediate shaft is provided with an intermediate shaft pinion and an intermediate shaft large gear. The main power output shaft is slidably provided with a two-axis transmission gear. The two-axis transmission gear can selectively mesh with the main power gear or the intermediate shaft pinion.

9. The vertical turning and milling compound machine tool with a central column according to claim 1, characterized in that, A rotation speed measuring device is provided between the rotary table body and the base, and the rotation speed measuring device is a circular magnetic encoder.

10. The vertical turning and milling compound machine tool with a central column according to claim 9, characterized in that, The circular magnetic encoder includes at least one circular magnetic grid, each of which contains at least two reading heads. The reading heads are fixedly connected to the base via a reading head bracket. The circular magnetic grid corresponds to the height of the reading head and is circumferentially arranged on the side of the rotary table body.

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