Ultra-large numerical control forming gear grinding machine

Abstract

The invention relates to an ultra-large numerical control forming gear grinding machine which comprises a lathe bed, a finishing mechanism, a grinding head system, a workpiece rotary table and other kinematic chain assemblies. The degree of freedom of motion of the formed grinding wheel is restrained by linear axes X, Y and Z and rotating axes A, B and C2; and the corner positions of the diamond roller and the cylindrical gear depend on the rotating shaft B2 and the rotating shaft C. The bracket tool has the following advantages that (1) the bracket tool has the function of machining large-specification outer straight tooth and outer helical tooth cylindrical gears, and grinding of outer gear rings in different diameter ranges can be met by adjusting the radial distribution of the bracket tool; 2) whether the rotary table participates in linkage or not can complete the helical gear tooth groove machining process, and when helical motion of a machine tool is completely put on one side of a grinding head, the requirement of gear grinding reciprocating motion on high-precision dynamic response of the rotary table can be effectively reduced; and (3) the whole machine is compact in structure, the gear grinding precision can be guaranteed, and cost reduction and efficiency improvement are realized to a great extent.

Description

Technical Field

[0001] The present invention belongs to the field of advanced manufacturing technology, and particularly relates to an ultra-large numerical control form grinding machine applied to the precision manufacturing of large-sized external gear rings. Background Art

[0002] In the process of form grinding of involute helical cylindrical gears, the path planning between the form grinding wheel and the cylindrical gear blank is realized through the machine tool kinematic chain. As the core functional carrier of the numerical control gear grinding machine, the vibration and rigidity of the grinding system will significantly affect the reliability of the machine tool cutting process; at the same time, the manufacturing error of large gears largely depends on the geometric motion accuracy of the grinding head drive mechanism and the workpiece indexing turntable system.

[0003] When grinding cylindrical gears over 10 meters long, the total weight of the rotating parts, including the turntable table body, auxiliary faceplate, bracket tooling, and the gear itself, reaches more than 300 tons. Under such a large moment of inertia working condition, it is a very big challenge to require the turntable to perform high-precision reciprocating motion, and it is difficult to meet the requirements of the dynamic characteristics of the turntable for the synchronous spiral motion of the Z and C axes during the traditional helical gear form grinding process. At this time, it is not suitable to use the torque motor direct drive turntable commonly used in medium and small-sized gear manufacturing machine tools for the workbench drive of ultra-large gear grinding machines, and the transmission chain is long, and the motion error transmission path is more complex.

[0004] Publication No. CN102151909B proposes a 6-axis 5-linkage large numerical control gear processing machine tool, which can improve the machining accuracy and efficiency of large gears. However, its disadvantage is that the linear axis X is located below the workpiece turntable, and the conventional guide rail pairs corresponding to the bed body, such as hard rails, linear rails, inlaid steel rails, or hydrostatic guide rails, are often nearly 10 meters long. Some must adopt the segmented splicing combination process. The double-nut ball screw is long in size and heavy in weight. In the manual assembly process, it is more difficult to adjust the geometric positioning accuracy such as the straightness and parallelism of the two side guide rail surfaces and the axial clearance of the ball screw pair, and the debugging is more time-consuming and laborious. Moreover, higher configuration requirements are imposed on aspects such as the large torque and high power of the servo motor, which will greatly increase the procurement and subsequent maintenance costs of the whole machine and its components. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies existing in the prior art, and provide an ultra-large numerical control form grinding machine tool to meet the requirements of reducing the dynamic characteristics of the turntable for the reciprocating motion during gear grinding of ultra-large gear grinding machines, so as to solve the problem of high-efficiency and high-precision machining of large cylindrical gears.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A super-large CNC form grinding machine, comprising a machine bed (1), a dressing mechanism (8), a grinding head system (13) and a workpiece turntable (14); the degrees of freedom of movement of the form grinding wheel are constrained by linear axes X, Y and Z and rotary axes A, B and C2; the angular positions of the diamond roll and the cylindrical gear respectively depend on rotary axes B2 and C; the mutual positional relationship between all the linear axes and the rotary axes and the positive directions of movement along each axial direction all follow the determination principle of the right-handed Cartesian coordinate system.

[0008] The movement chain sequence of form grinding of the super-large CNC form grinding machine is: form grinding wheel → B axis → A axis → C2 axis

[0009] → Y axis → Z axis → X axis → machine bed → C axis → cylindrical gear. Similarly, the movement chain sequence of grinding wheel dressing is: diamond roll → B2 axis → X axis → Z axis → Y axis → C2 axis → A axis → B axis → form grinding wheel.

[0010] The dressing mechanism (8) consists of two B2-axis dressing motor spindles (9) and diamond rolls (10) of the same specification arranged horizontally and symmetrically along the Y-axis direction, and the base of the dressing motor spindle (9) is installed on a dressing bracket fixedly connected to the top of the X-axis column (2). During the dressing of the grinding wheel, the dressing motor spindle (9) drives the diamond roll (10) to rotate at a constant high speed around the B2 axis.

[0011] The grinding head system (13) consists of a B-axis grinding motor spindle (7) and a form grinding wheel (11), and its linear reciprocating movements relative to the workpiece in the radial, tangential and axial directions are respectively realized by the feed systems of linear axes X, Y and Z, and the yaw is driven by rotary axes A and C2. Each linear axis adopts a double-nut ball screw pair, and a linear grating scale is equipped for the guide rail, and a circular grating is installed for the rotary shaft. Each numerical control axis is a fully closed-loop control. When grinding a gear, the grinding motor spindle (7) drives the form grinding wheel (11) to rotate at a uniform high speed around the B axis.

[0012] The driving device for the radial movement of the X-axis column (2) is: the X-axis servo motor Mx is installed on one side of the input shaft of the planetary reducer, and both are in a horizontally suspended state; two coaxial bearing seats are installed in the middle of the transverse guide rails on both sides of the machine bed (1) along the X-axis direction, which are respectively the fixed end and the supporting end of the ball screw, and the left end face of the fixed-end bearing seat is rigidly connected to one side of the output shaft of the planetary reducer, and drives the screw to rotate through an intermediate coupling; a transition plate is arranged between the X-axis column (2) and the screw nut seat and fastened with inner hexagon socket head cap screws; the transverse guide rail for the X-axis to move forward and backward is usually a linear guide rail or a hydrostatic guide rail;

[0013] The driving device for the axial movement of the Z-axis slide (3) is as follows: The Z-axis servo motor Mz is installed on one side of the input shaft of the right-angle reducer, both in a suspended state, and the right-angle reducer is a hypoid gear pair; the bearing seats at both ends of the ball screw along the Z-axis direction are located in the middle of the vertical guide rails on both sides of the X-axis column (2), and the left end face of the fixed-end bearing seat is connected to one side of the output shaft of the right-angle reducer, driving the screw to rotate through an intermediate coupling; a transition plate is provided between the Z-axis slide (3) and the screw nut seat; the vertical guide rails for the Z-axis lifting mainly adopt linear guide rails or hydrostatic guide rails.

[0014] The driving device for the tangential movement of the Y-axis carriage (4) is similar to that of the X-axis column (2), the difference being that the bearing seats at both ends of the ball screw are installed in the middle of the longitudinal guide rails on both sides of the Z-axis slide (3), and there is no need for a transition plate between the Y-axis carriage (4) and the screw nut seat; the longitudinal guide rails for the Y-axis reciprocation are linear guide rails.

[0015] If the linear axis X is a hydrostatic guide rail, the hole centers of the bearing seats at both ends of the ball screw and the screw nut seat need to be accurately adjusted to "three holes concentric". The following two axial centering installation methods can be adopted:

[0016] (3) Turn on the hydrostatic mode. After the X-axis column (2) floats evenly, the oil film thickness is a fixed value. Adjust the axial heights of the screw nut seat and the bearing seats at both ends to be the same by tightening or loosening the adjusting screws multiple times respectively.

[0017] (4) Symmetrically arrange multiple support cylinders at equal intervals on both sides of the X-axis column (2) so that the gap between the lower bottom surface of the column and the guide rail surface of the bed (1) is about 0.02 - 0.06 mm, which is numerically equal to the thickness of the hydraulic oil film during hydrostatic operation.

[0018] With the lower bottom surface of the column in a suspended state, adjust the screw nut seat and the bearing seats at both ends to be at the same height, and make the axis of the screw parallel to the guide rail; when starting up, wait for the hydrostatic oil film thickness to stabilize and then lower the support; before shutting down, first jack up the cylinder.

[0019] Then turn off the hydrostatic mode, thereby realizing the equivalent substitution of mechanical support and hydrostatic oil film.

[0020] The ultra-large CNC form grinding machine also includes a C2-axis rotation mechanism (5) and an A-axis rotation mechanism (6); one side of the coupling is connected to the output shaft of the planetary reducer, and the other side is connected to the worm shaft. The worm drives the worm wheel to realize the forward and reverse indexing motion. The C2-axis rotation mechanism (5) is installed on the bracket of the Y-axis carriage (4), and the rotating shaft of the C2 axis is parallel to the Z axis. The A-axis rotation mechanism (6) is located on the right side of the C2-axis rotation mechanism (5), and the rotating shaft of the A axis is parallel to the X axis. The rotating shafts C2 and A can respectively drive the form grinding wheel (11) to deflect a certain angle around its axis. During the form grinding of helical gears, usually the rotation angles of the A axis and the C2 axis respectively depend on the helix angle and the up-and-down movement amount along the tooth width.

[0021] The workpiece turntable (14) is a hydrostatic turntable. Compared with the transmission device of the C2 axis, the workpiece turntable (14) is fixedly connected to the machine body (1). The double worm gear and double worm pair are used as the end transmission components. The indexing worm is connected to the planetary reducer by a servo motor and is coaxial with the coupling. At the same time, a pair of spur cylindrical gear pairs with equal number of teeth in mesh must be set. The side driven by the passive gear is the damping worm. By adjusting the piston movement direction of the backlash elimination cylinder through the hydraulic system, the axial backlash of the worm can be accurately and adaptively distributed in real time for backlash compensation, and the synchronous motion transmission between the two worms with equal and opposite helix angles can be realized, thereby controlling the precise indexing rotary motion of the worm wheel located at the turntable spindle.

[0022] Above the C-axis turntable (14), a concentric auxiliary faceplate (15) is provided. On the upper end face of the auxiliary faceplate (15), a plurality of equal-specification bracket toolings (16) are evenly arranged in a circumferential array for supporting the cylindrical gear (12) to be machined. By adjusting the distribution diameter of the bracket toolings (16), the clamping of large-sized external gear rings with different diameters can be realized. Usually, a number of support cylinders of the same type are evenly arranged on the outer ring of the auxiliary faceplate (15).

[0023] When grinding the straight-tooth external gear ring, after the C-axis of the turntable indexes in place, control the Z-axis to move up and down to grind the tooth groove; when grinding the helical-tooth external gear ring, after the C-axis of the turntable indexes in place, the tool rest A-axis tilts in place according to the helix angle of the helical gear, and control the C2-axis, X-axis, Y-axis and Z-axis to move synchronously to grind the tooth groove, ensuring that the center of the form grinding wheel moves in a helical motion relative to the helical gear.

[0024] A super-large CNC form grinding machine of the present invention, when grinding the straight external gear ring, after the indexing of the rotary table C-axis is in place, the Z-axis is controlled to move up and down to grind the tooth groove; when grinding the helical external gear ring, after the indexing of the rotary table C-axis is in place, the tool rest A-axis tilts in place according to the helix angle of the helical gear, and the C2-axis, X-axis, Y-axis and Z-axis are controlled to move synchronously in linkage to grind the tooth groove, ensuring that the center of the form grinding wheel moves in a spiral relative to the helical gear. Since the rotary table does not need to participate in the linkage when grinding the helical cylindrical gear, the relative spiral movement of the grinding wheel and the gear is all completed on the grinding wheel side. The mass of the moving parts on the grinding wheel side is relatively low, and it is easier to control compared to the rotary table side.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1) It has the function of processing large-sized external straight teeth and external helical cylindrical gears. By adjusting the radial distribution of the bracket tooling, grinding of external gear rings with different diameter ranges can be satisfied;

[0027] 2) The processing process of the helical gear tooth groove can be completed whether the rotary table participates in the linkage or not. When all the spiral movements of the machine tool are placed on the grinding head side, the requirements for the high-precision dynamic response of the rotary table caused by the reciprocating movement of gear grinding can be effectively reduced;

[0028] 3) The overall structure of the machine is compact, which is beneficial to ensuring the gear grinding accuracy and achieving cost reduction and efficiency increase to a great extent. Description of the Drawings

[0029] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0030] Figure 1 It is a schematic diagram of the overall structure of the machine.

[0031] Figure 2 It is a motion chain diagram of the gear grinding machine.

[0032] Figure 3 It is a topological structure diagram of the gear grinding machine.

[0033] Figure 4 It is a diagram of the overall transmission system of the machine.

[0034] In the figure: 1. Bed; 2. X-axis column; 3. Z-axis slide; 4. Y-axis carriage; 5. C2-axis rotating mechanism; 6. A-axis rotating mechanism; 7. B-axis grinding electric spindle; 8. Dressing mechanism; 9. B2-axis dressing electric spindle; 10. Diamond roller; 11. Form grinding wheel; 12. Cylindrical gear; 13. Grinding head system; 14. C-axis rotary table; 15. Auxiliary faceplate; 16. Bracket tooling. Specific Embodiments

[0035] The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that these descriptions are only descriptive and exemplary, and should not be construed as limiting the scope of protection of the present invention.

[0036] As Figures 1 to 4 , a super-large CNC form grinding machine includes a machine body 1, a dressing mechanism 8, a grinding head system 13, a workpiece turntable 14, and other kinematic chain components. The degrees of freedom of movement of the form grinding wheel are constrained by the linear axes X, Y, and Z and the rotary axes A, B, and C2; the angular positions of the diamond roll and the cylindrical gear respectively depend on the rotary axes B2 and C. The mutual positional relationship of all linear axes and rotary axes and the positive directions of movement along each axial direction all follow the determination principle of the right-handed Cartesian coordinate system.

[0037] The kinematic chain sequence of form grinding can be simplified as: form grinding wheel → B axis → A axis → C2 axis → Y axis → Z axis → X axis → machine body → C axis → cylindrical gear. Similarly, the kinematic chain sequence of grinding wheel dressing is: diamond roll → B2 axis → X axis → Z axis → Y axis → C2 axis → A axis → B axis → form grinding wheel.

[0038] The dressing mechanism 8 is composed of two B2-axis dressing electric spindles 9 and diamond rolls 10 of the same specification that are horizontally symmetrically arranged along the Y-axis direction, and the base of the dressing electric spindle 9 is installed on a dressing bracket fixedly connected to the top of the X-axis column 2. During the dressing process of the grinding wheel, the dressing electric spindle 9 drives the diamond roll 10 to rotate around the B2 axis at a constant high speed.

[0039] The grinding head system 13 is composed of a B-axis grinding electric spindle 7 and a form grinding wheel 11. Its linear reciprocating motions in the radial, tangential, and axial directions relative to the workpiece are respectively realized by the feed systems of the linear axes X, Y, and Z, and the yaw is driven by the rotary axes A and C2. Each linear axis adopts a double-nut ball screw pair, and a linear grating scale is equipped for the guide rail. The rotary axis is installed with a circular grating, and each numerical control axis is controlled in a full-closed loop manner to improve the positioning accuracy. When grinding a gear, the grinding electric spindle 7 drives the form grinding wheel 11 to rotate around the B axis at a uniform high speed.

[0040] The driving device for the radial movement of the X-axis column 2 is: the X-axis servo motor Mx is installed on one side of the input shaft of the planetary reducer, both in a horizontally suspended state; two coaxial bearing seats are installed in the middle of the transverse guide rails on both sides of the machine body 1 along the X-axis direction, which are respectively the fixed end and the support end of the ball screw, and the left end face of the fixed-end bearing seat is rigidly connected to one side of the output shaft of the planetary reducer, and drives the screw to rotate through an intermediate coupling; a transition plate is arranged between the X-axis column 2 and the screw nut seat and fastened with inner hexagon socket head cap screws; the transverse guide rail for the X-axis to move forward and backward is usually a linear guide rail or a hydrostatic guide rail.

[0041] The driving device for the axial movement of the Z-axis slide 3 is as follows: The Z-axis servo motor Mz is installed on one side of the input shaft of the right-angle reducer, both in a suspended state, and the right-angle reducer is a hypoid gear pair; the bearing seats at both ends of the ball screw along the Z-axis direction are located in the middle of the vertical guide rails on both sides of the X-axis column 2, and the left end face of the fixed-end bearing seat is connected to one side of the output shaft of the right-angle reducer, driving the screw to rotate through an intermediate coupling; a transition plate is provided between the Z-axis slide 3 and the screw nut seat; the vertical guide rails for the Z-axis lifting mainly adopt linear guide rails or hydrostatic guide rails.

[0042] The driving device for the tangential movement of the Y-axis carriage 4 is similar to that of the X-axis column 2, the difference being that the bearing seats at both ends of the ball screw are installed in the middle of the longitudinal guide rails on both sides of the Z-axis slide 3, and there is no need for a transition plate between the Y-axis carriage 4 and the screw nut seat; the longitudinal guide rails for the Y-axis reciprocation are linear guide rails.

[0043] If the linear axis X selects a hydrostatic guide rail, the hole centers of the bearing seats at both ends of the ball screw and the screw nut seat need to be accurately adjusted to "three holes concentric". The following two axial centering installation methods can be adopted:

[0044] Turn on the hydrostatic mode. After the X-axis column 2 floats evenly, the oil film thickness is a fixed value. Adjust the axial center height of the screw nut seat and the bearing seats at both ends to be the same by tightening or loosening the adjusting screws multiple times respectively.

[0045] A plurality of support oil cylinders are symmetrically arranged at equal intervals on both sides of the X-axis column 2, so that the gap between the lower bottom surface of the column and the guide rail surface of the bed 1 is about 0.02 - 0.06 mm, which is numerically equal to the thickness of the hydraulic oil film during hydrostatic operation. With the lower bottom surface of the column in a suspended state, adjust the screw nut seat and the bearing seats at both ends to be at the same height, and the axis of the screw is parallel to the guide rail. When starting up, after the hydrostatic oil film thickness is stable, lower the support; before shutting down, first jack up the oil cylinder and then turn off the hydrostatic mode, thus realizing the equivalent substitution of mechanical support and hydrostatic oil film.

[0046] The driving devices of the C2-axis rotating mechanism 5 and the A-axis rotating mechanism 6 are similar. The servo motor is installed on one side of the input shaft of the planetary reducer and is placed in a suspended state; one side of the coupling is connected to the output shaft of the planetary reducer, and the other side is connected to the worm shaft, and the worm drives the worm wheel to achieve positive and negative rotation indexing motion. The C2-axis rotating mechanism 5 is installed on the bracket of the Y-axis carriage 4, and the rotating shaft of the C2-axis is parallel to the Z-axis. The A-axis rotating mechanism 6 is located on the right side of the C2-axis rotating mechanism 5, and the rotating shaft of the A-axis is parallel to the X-axis. The rotating shafts C2 and A can respectively drive the form grinding wheel 11 to deflect a certain angle around its axis. During the helical gear form grinding process, usually the rotation angles of the A-axis and the C2-axis respectively depend on the helix angle and the up and down movement amount along the tooth width.

[0047] The workpiece turntable 14 is a hydrostatic turntable. Compared with the transmission device of the C2 axis, the workpiece turntable 14 is fixedly connected to the machine body 1. It uses a double-worm and double-worm gear pair as the end transmission component, and has the motion characteristics of low speed, large torque, no backlash, and high precision. Among them, the indexing worm is connected by a servo motor to a planetary reducer and is coaxial with the coupling. At the same time, a pair of spur gear pairs with equal number of teeth meshing must be set, and the side driven by the passive gear is the damping worm. By adjusting the piston movement direction of the backlash elimination cylinder through the hydraulic system, the axial runout amount of the worm can be accurately and adaptively allocated in real time for backlash compensation, and the synchronous motion transmission between the two worms with equal and opposite helix angles can be realized, thereby controlling the precise indexing rotation motion of the worm gear located at the turntable spindle.

[0048] Above the C-axis turntable 14, a coaxial auxiliary faceplate 15 is provided. On the upper end face of the auxiliary faceplate 15, a plurality of bull-leg workpieces 16 of the same specification are evenly arranged in a circumferential array for supporting the cylindrical gear 12 to be machined. By adjusting the distribution diameter of the bull-leg workpieces 16, clamping of large-sized external gear rings with different diameters can be realized. Usually, several support cylinders of the same type are evenly arranged on the outer ring of the auxiliary faceplate 15 to reduce the load and driving torque of the rotary table.

[0049] For a super-large CNC form grinding machine of the present invention, when grinding a straight-tooth external gear ring, after the C-axis of the turntable is indexed in place, the Z-axis is controlled to move up and down to grind the tooth groove; when grinding an inclined-tooth external gear ring, after the C-axis of the turntable is indexed in place, the tool rest A-axis is tilted in place according to the helix angle of the helical gear, and the C2-axis, X-axis, Y-axis, and Z-axis are controlled to move synchronously to grind the tooth groove, ensuring that the center of the form grinding wheel moves in a helical motion relative to the helical gear. Since the turntable does not need to participate in the linkage when grinding a helical cylindrical gear, the relative helical motion of the grinding wheel and the gear is all completed on the grinding wheel side. The mass of the moving parts on the grinding wheel side is relatively low, and it is easier to control compared to the turntable side.

[0050] The above embodiments only describe the preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims

1. An ultra-large CNC profile gear grinding machine, characterized in that: The invention comprises a bed (1), a dressing mechanism (8), a grinding head system (13) and a workpiece turntable (14); the freedom of motion of the forming grinding wheel is constrained by linear axes X, Y and Z and rotation axes A, B and C2; the angular positions of the diamond roller and the cylindrical gear depend on the rotation axes B2 and C respectively; the relative positional relationship between all linear axes and the rotation axes and the positive direction of motion along each axial direction all follow the determination principle of the right-handed Cartesian coordinate system.

2. The super large CNC profile gear grinding machine according to claim 1, characterized in that: The kinematic chain sequence of the super large CNC profile gear grinding machine is: profile grinding wheel → B axis → A axis → C2 axis → Y axis → Z axis → X axis → bed → C axis → cylindrical gear. Similarly, the kinematic chain sequence of the grinding wheel dressing is: diamond roller → B2 axis → X axis → Z axis → Y axis → C2 axis → A axis → B axis → profile grinding wheel.

3. The super large CNC profile gear grinding machine according to claim 1, characterized in that: The dressing mechanism (8) is composed of two B2-axis dressing electric spindles (9) and diamond rollers (10) of equal specifications arranged horizontally and symmetrically along the Y-axis direction, and the base of the dressing electric spindle (9) is installed on a dressing bracket fixedly connected to the top of the X-axis column (2). During the grinding wheel dressing process, the dressing electric spindle (9) drives the diamond roller (10) to rotate around the B2 axis at a constant high speed.

4. The super large CNC profile gear grinding machine according to claim 1, characterized in that: The grinding head system (13) is composed of a B-axis grinding electric spindle (7) and a forming grinding wheel (11). Its linear reciprocating motion relative to the workpiece in radial, tangential and axial directions is achieved by the feed systems of the linear axes X, Y and Z respectively, and the yaw is driven by the rotating axes A and C2. Each linear axis adopts a double-nut ball screw pair, and the guide rail is equipped with a linear grating ruler, and the rotary axis is equipped with a circular grating. Each CNC axis is fully closed-loop controlled. When grinding gears, the grinding electric spindle (7) drives the forming grinding wheel (11) to rotate uniformly and at high speed around the B axis.

5. The super large CNC profile gear grinding machine according to claim 4, characterized in that: The driving device for the radial movement of the X-axis column (2) is as follows: an X-axis servo motor Mx is installed on one side of the input shaft of the planetary reducer, both of which are in a horizontal suspended state; two coaxial bearing seats are installed in the middle of the transverse guide rails on both sides of the bed (1) along the X-axis direction, which are the fixed end and the supporting end of the ball screw respectively, and the left end surface of the fixed end bearing seat is rigidly connected to one side of the output shaft of the planetary reducer, and drives the screw to rotate through the intermediate coupling; a transition plate is arranged between the X-axis column (2) and the screw nut seat, and is fastened with a hexagon socket head screw; the transverse guide rail for the advance and retreat of the X-axis is usually a linear guide rail or a hydrostatic guide rail; The driving device for the axial movement of the Z-axis slide (3) is as follows: the Z-axis servo motor Mz is installed on one side of the input shaft of the right-angle reducer, both of which are in a suspended state, and the right-angle reducer is a hypoid gear pair; the bearing seats at both ends of the ball screw along the Z-axis direction are located in the middle of the vertical guide rails on both sides of the X-axis column (2), and the left end surface of the fixed end bearing seat is connected to one side of the output shaft of the right-angle reducer, and the screw is driven to rotate through an intermediate coupling; a transition plate is arranged between the Z-axis slide (3) and the screw nut seat; the vertical guide rail for Z-axis lifting mainly adopts a linear guide rail or a hydrostatic guide rail; The driving device for the tangential motion of the Y-axis carriage (4) is similar to that of the X-axis column (2), except that the bearing seats at both ends of the ball screw are installed in the middle of the longitudinal guide rails on both sides of the Z-axis slide (3), and no transition plate is required between the Y-axis carriage (4) and the screw nut seat; the longitudinal guide rail for the Y-axis to and fro is a linear rail.

6. The super large CNC profile gear grinding machine according to claim 5, characterized in that: If the linear axis X is a hydrostatic guide rail, the hole centers of the bearing seats at both ends of the ball screw and the screw nut seat must be accurately adjusted to "three holes concentric", and the following two axial centering installation methods can be used: (1) Turn on the static pressure mode, and after the X-axis column (2) floats evenly and the oil film thickness is constant, tighten or loosen the adjusting screws several times to adjust the axial heights of the screw nut seat and the bearing seats at both ends to be the same; (2) multiple supporting cylinders are symmetrically arranged at equal intervals on both sides of the X-axis column (2) so that the gap between the bottom surface of the column and the guide surface of the bed (1) is about 0.02 to 0.06 mm, which is numerically equal to the thickness of the hydraulic oil film during static pressure operation; When the bottom surface of the column is suspended, adjust the screw nut seat and the bearing seats at both ends to the same height, and the screw axis is parallel to the guide rail; when starting the machine, wait until the static pressure oil film thickness is stable, then put down the support; before shutting down the machine, first lift the oil cylinder, Then turn off the static pressure mode, thereby achieving equivalent replacement of mechanical support and static pressure oil film.

7. The super large CNC profile gear grinding machine according to claim 1, characterized in that: The yaw structure of the grinding head system (13) includes a C2-axis rotating mechanism (5) and an A-axis rotating mechanism (6); one side of the coupling is connected to the output shaft of the planetary reducer, and the other side is connected to the worm shaft, and the worm drives the worm wheel to realize forward and reverse indexing motion. The C2-axis rotating mechanism (5) is installed on the bracket of the Y-axis carriage (4), and the rotating axis of the C2 axis is parallel to the Z axis. The A-axis rotating mechanism (6) is located on the right side of the C2-axis rotating mechanism (5), and the rotating axis of the A axis is parallel to the X axis. The rotating axes C2 and A can respectively drive the forming grinding wheel (11) to deflect a certain angle around its axis. In the process of forming the helical gear, the rotation angles of the A axis and the C2 axis usually depend on the helix angle and the amount of up and down movement along the tooth width, respectively.

8. The super large CNC profile gear grinding machine according to claim 1, characterized in that: The workpiece turntable (14) is a hydrostatic turntable. Compared with the transmission device of the C2 axis, the workpiece turntable (14) and the bed (1) are fixedly connected. A double worm gear and double worm pair are used as the terminal transmission assembly. The servo motor is connected to the planetary reducer and the indexing worm is coaxial with the coupling. At the same time, a pair of spur gear pairs with equal teeth meshing must be set, and the side driven by the passive wheel is a damping worm. The piston movement direction of the anti-backlash cylinder is adjusted by the hydraulic system, and the axial movement of the worm can be accurately distributed in real time to compensate for the backlash, and the synchronous motion transmission between the two worms with equal and opposite helical angles can be realized, thereby controlling the precise indexing rotation motion of the worm wheel located at the turntable core shaft. A coaxial auxiliary faceplate (15) is arranged above the C-axis turntable (14), and a plurality of bracket fixtures (16) of the same specification are evenly arranged in a circumferential array on the upper end surface of the auxiliary faceplate (15) to support the cylindrical gear (12) to be processed. The large-size external gear rings of different diameters can be clamped by adjusting the distribution diameter of the bracket fixtures (16). Usually, a plurality of support cylinders of the same model are evenly arranged on the outer ring of the auxiliary faceplate (15).

9. The super large CNC profile gear grinding machine according to claim 1, characterized in that: When grinding a spur gear external ring, after the C-axis of the turntable is indexed into place, the Z-axis is controlled to move up and down to grind the tooth groove; when grinding a helical gear external ring, after the C-axis of the turntable is indexed into place, the A-axis of the tool holder is tilted into place according to the helix angle of the helical gear, and the C2 axis, X axis, Y axis and Z axis are controlled to grind the tooth groove synchronously to ensure that the center of the forming grinding wheel moves in a spiral motion relative to the helical gear.

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