A special fixture for turning of a thin-walled part of a heterogeneous gyratory body and a precision machining method

Abstract

The application discloses a special fixture for turning of a heterogeneous rotary body thin-wall part and a precision machining method, relates to the technical field of special fixtures for turning of rotary bodies, and comprises a conical two-stage telescopic servo hydraulic system, an inner supporting module and an outer clamping module. The conical two-stage telescopic servo hydraulic system is of Morse taper structure, is connected with a machine tool through a left end pull rod, is internally provided with a first-stage chamber and a second-stage chamber, and is provided with an inner cylinder and a piston rod which are respectively installed in sliding fashions along an axial direction. The inner supporting module comprises an inner wall supporting mechanism and a selectable rib plate supporting mechanism. The special fixture for turning of the heterogeneous rotary body thin-wall part is compact in structure, can adopt outer clamping, inner supporting and rib plate limiting to realize multifunctional positioning and clamping of the thin-wall part, is convenient to mount and dismount, is stable in clamping, and is high in clamping efficiency. The precision machining method improves the machining precision and surface quality of the thin-wall part, effectively controls clamping and machining deformation, reduces product rejection rate, improves machining efficiency, and reduces machining cost.

Description

Technical Field

[0001] This invention belongs to the technical field of special fixtures for turning rotating bodies, specifically relating to a special fixture for turning thin-walled parts of heterogeneous rotating bodies and a precision machining method. Background Technology

[0002] In recent years, heterogeneous thin-walled rotating parts have been increasingly widely used in the field of mechanical manufacturing. Their main structural feature is the addition of thin-walled transverse ribs perpendicular to the axis of rotation within a thin-walled rotating body. This requires precision machining of the inner and outer walls of the thin-walled rotating body, as well as precision machining of the rib surfaces and drilling of the rib bosses parallel to the axis of rotation. Due to the low stiffness at the thin-walled sections and ribs, the workpiece is prone to deformation during clamping and cutting, affecting machining accuracy and quality. The materials used for thin-walled parts are generally difficult-to-machine materials such as high-strength steel, high-hardness steel, and heat-resistant alloys. These materials are characterized by high strength, high hardness, and low thermal conductivity, resulting in high cutting forces, ineffective heat dissipation, and severe tool wear during machining, leading to significant machining deformation. Furthermore, these workpieces require high machining accuracy and surface quality, generally requiring an accuracy grade of IT7 or higher. Key accuracy indicators include:

[0003] 1) Surface roughness requirement is higher than Ra 0.8 μm;

[0004] 2) Roundness and cylindricity of the outer and inner walls of the workpiece;

[0005] 3) Coaxiality of the inner and outer axis of the workpiece;

[0006] 4) Perpendicularity of the workpiece end face, transverse rib plate, and outer wall axis;

[0007] 5) Coaxiality between the axis of the transverse rib plate hole and the axis of the outer wall.

[0008] Existing clamping methods and machining technologies are insufficient to meet the requirements for product size and shape accuracy. Furthermore, the clamping and machining processes are complex, resulting in low efficiency and high costs, making them unsuitable for mass production. This paper proposes clamping schemes and precision machining methods for heterogeneous rotating thin-walled parts made of difficult-to-machine materials, adapting to the mass production needs of high-tech products and solving common problems in advanced manufacturing. Summary of the Invention

[0009] The purpose of this invention is to provide a special turning fixture and precision machining method for heterogeneous rotating thin-walled parts, in order to solve the technical problems of existing fixtures for rotating thin-walled parts, such as large clamping deformation, unstable clamping, difficulty in disassembling thin-walled parts, unsuitability for mass production, and easy deformation and vibration during the cutting process.

[0010] The specialized fixture features a compact structure with multi-functional positioning and clamping capabilities including external clamping, internal support, and rib plate support. The simultaneous clamping of internal and external jaws effectively solves the problem of large clamping deformation. It ensures no deformation during clamping while significantly increasing clamping force and guaranteeing clamping stability. The two-stage hydraulic servo drive system provides graded control, facilitating the loading and unloading of thin-walled parts and improving clamping efficiency. Precise selection of cutting parameters reduces cutting force, delays tool wear, and suppresses vibration, resolving issues such as deformation and vibration during the machining of thin-walled parts, thus improving surface quality and machining accuracy. The cutting speed is three to four times higher than conventional cutting, further enhancing machining efficiency.

[0011] To achieve the above objectives, the first aspect of the present invention provides a special turning fixture for heterogeneous rotating thin-walled parts, comprising:

[0012] A conical two-stage telescopic servo hydraulic system includes a conical hydraulic cylinder. The conical hydraulic cylinder has a primary chamber, and an inner cylinder is slidably installed along the axial direction of the primary chamber. The inner cylinder has a secondary chamber, and a piston rod is slidably installed along the axial direction of the secondary chamber. A front cylinder cover is installed at the right open end of the inner cylinder, and a central through hole is opened along the axial direction of the front cylinder cover. The right end of the piston rod extends out through the central through hole.

[0013] An internal support module, the internal support module including an inner wall support mechanism and a rib support mechanism;

[0014] The inner wall support mechanism is located at the right protruding end of the inner cylinder. The inner wall support mechanism includes three inner support claws, which are equidistantly distributed along the circumferential direction of the inner wall of the workpiece to support the inner wall of the workpiece.

[0015] The rib support mechanism is located at the right end of the piston rod. The rib support mechanism includes a support plate, which abuts against the rib of the workpiece to support the rib of the workpiece.

[0016] The external clamping module includes a three-jaw chuck and three external jaws equidistantly distributed along the circumference of the three-jaw chuck. The three external jaws apply a centripetal clamping force to the outer wall of the workpiece to clamp the outer wall of the workpiece.

[0017] According to the present invention, a special fixture for turning thin-walled heterogeneous rotating parts is provided, wherein the conical hydraulic cylinder includes a conical outer cylinder with a Morse taper structure, which is transitionally fitted with the inner hole of the machine tool spindle and connected to the machine tool tie rod through the left end tie rod connecting hole.

[0018] According to the present invention, the three outer jaws of the special turning fixture for thin-walled heterogeneous rotating parts correspond to the positions of the three inner support jaws.

[0019] According to the present invention, a special fixture for turning thin-walled parts of heterogeneous rotating bodies is provided, wherein a guide sleeve is interference-fitted to the right protruding end of the inner cylinder, and the guide sleeve is fixedly connected to the conical hydraulic cylinder by bolts, and a part of the guide sleeve extends into the conical hydraulic cylinder; a circular array of annular splines is provided in the middle of the inner cylinder, and a spline keyway that is clearance-fitted with the annular splines is provided on the inner wall of the conical hydraulic cylinder, wherein the axial length of the spline keyway is greater than the axial length of the annular splines.

[0020] According to the present invention, a special fixture for turning thin-walled parts of heterogeneous rotating bodies is provided, wherein a rear cylinder cover is provided on the left side of the conical hydraulic cylinder, and an oil inlet / outlet b and an oil inlet / outlet a are provided on the rear cylinder cover;

[0021] The inner cylinder has a piston structure on the left side, and the primary chamber is divided into a primary left chamber and a primary right chamber by the piston structure of the inner cylinder.

[0022] The piston rod has a piston structure on its left side, and the secondary chamber is divided into a secondary left chamber and a secondary right chamber by the piston structure of the piston rod;

[0023] The inner wall of the inner cylinder is provided with a first oil passage on the left side. One end of the first oil passage is connected to the oil inlet / outlet b through a first-stage left chamber. A first-stage servo reversing valve is provided at the connection between the first oil passage and the first-stage left chamber. The other end of the first oil passage is connected to the second-stage left chamber.

[0024] A second oil passage is provided on the left side of the inner wall of the conical hydraulic cylinder. One end of the second oil passage is connected to the inlet / outlet a, and the other end of the second oil passage is connected to the first-stage right chamber.

[0025] A third oil passage is provided on the right side of the inner wall of the conical hydraulic cylinder. One end of the third oil passage is connected to the first-stage right chamber, and a second-stage servo directional valve is provided at the connection between the third oil passage and the first-stage right chamber. The other end of the third oil passage is connected to the second-stage right chamber.

[0026] Loading process: Oil is supplied through inlet / outlet b, oil inlet / outlet a is opened, the first-stage servo directional valve and the second-stage servo directional valve are closed, oil enters the left chamber of the first-stage chamber and exits the right chamber, the inner cylinder moves to the right, after the inner support claw is in place, the first-stage directional valve is opened, at this time oil inlet / outlet b continues to supply oil, the oil enters the left chamber of the second-stage chamber from the left chamber of the first-stage chamber, the piston rod moves to the right, the oil from the right chamber of the second-stage chamber flows into the right chamber of the first-stage chamber and then flows out from inlet / outlet a.

[0027] Unloading process: Oil is introduced through inlet / outlet a, and inlet / outlet b is opened. Similarly, the inner cylinder retracts first, and the piston rod retracts after the secondary servo reversing valve is opened.

[0028] According to the present invention, a special fixture for turning thin-walled parts of heterogeneous rotating bodies is provided. The inner wall support mechanism includes a connecting rod disk, which is disposed on the right side of the front cylinder head. The connecting rod disk has a central hole for the piston rod to extend out. At least three connecting rod seats are equidistantly arranged circumferentially on the right end face of the connecting rod disk. One end of two parallel connecting rods is hinged and fixed on each connecting rod seat. An inner support slider is hinged and fixed to the other end of every two connecting rods. Each inner support slider is connected to a corresponding inner support claw. A clamping force is applied to the inner wall of the workpiece through the three inner support claws.

[0029] According to the special turning fixture for heterogeneous rotating thin-walled parts provided by the present invention, an outer cover is installed on the right side of the conical hydraulic cylinder, and at least three slider grooves are formed on the right side surface of the outer cover in the radial direction, and the inner support slider is slidably connected to the slider grooves.

[0030] According to the present invention, a special fixture for turning thin-walled parts of heterogeneous rotating bodies is provided, wherein the rib support mechanism includes a support disk, one end face of the support disk abuts against the rib of the workpiece, and the other end face of the support disk is provided with a support shaft in the vertical direction. One end of the support shaft is connected to the support disk, and the other end of the support shaft is connected to the piston rod, and the central axes of the support shaft and the piston rod are on the same straight line.

[0031] A second aspect of the present invention provides a precision machining method for turning a heterogeneous thin-walled part of rotation, using the aforementioned special turning fixture for the heterogeneous thin-walled part of rotation, comprising the following steps:

[0032] Step 1: Rough machining preparation. Determine the cutting parameters and tools based on the material properties, and determine the number of passes based on the machining allowance.

[0033] Step 2: Clamp the workpiece at end B. Select a circular support plate. Extend the inner cylinder to open the inner support claws and clamp the inner wall of end B of the workpiece. Extend the piston rod to make the circular plate contact the workpiece rib and provide support force. Then use a constant torque wrench to move the outer jaws of the three-jaw chuck towards the center to clamp the outer wall of end B of the workpiece.

[0034] Step 3: Semi-finish machining of end A, with a cutting speed of 100m / min to 150m / min, a feed rate of 0.1mm / r to 0.15mm / r, a cutting depth of 0.1mm to 0.2mm, and a allowance of less than 0.2mm. Use a 0.4mm carbide coated tool to machine the outer wall and end face, and use a 0.8mm carbide coated tool to machine the inner wall and ribs.

[0035] Step 4: Finish machining end A. The cutting speed is 150m / min to 200m / min, the feed rate is no more than 0.1mm / r, the cutting depth is 0.05 to 0.1mm, and the cutting is done in multiple passes. Use a R0.4mm or R0.8mm carbide coated tool to machine the outer wall and end face, and use a R0.4mm or R0.8mm carbide coated tool to machine the inner wall and ribs.

[0036] Step 5: Inspect and compensate for the finishing of the outer and inner walls of end A. The cutting speed is 200m / min~300m / min, the feed rate is no more than 0.05mm / r, the cutting depth is less than 0.05mm, and a R0.8mm carbide coated tool is used.

[0037] Step 6: Disassemble the workpiece, clamp the workpiece at end A, select the irregular-shaped disk according to the processing requirements, and the clamping operation steps are the same as in Step 2;

[0038] Step 7: Semi-finish workpiece B end, select a cutting speed of 100m / min~150m / min, a feed rate of 0.1mm / r~0.15mm / r, a cutting depth of 0.1~0.2mm, leaving a allowance of less than 0.2mm, use an R0.8mm carbide coated tool to machine the end face and outer wall, and use an R0.4mm carbide coated tool to machine the inner wall and rib plate;

[0039] Step 8: Finish machining end B of the workpiece. Select a cutting speed of 150m / min to 200m / min, a feed rate of no more than 0.1mm / r, a cutting depth of 0.05 to 0.1mm, and perform multiple passes. Use a R0.4mm or R0.8mm carbide coated tool to machine the end face and outer wall, and use a R0.4mm or R0.8mm carbide coated tool to machine the inner wall and ribs.

[0040] Step 9: Inspect and compensate for the finishing of the outer and inner walls of end B. The cutting speed is 200m / min~300m / min, the feed rate is no more than 0.05mm / r, the depth of cut is less than 0.05mm, and a R0.8mm carbide coated tool is used.

[0041] Step 10: The spindle speed is 1000-8000 r / min, and the feed rate is no more than 0.15 mm / r. Use an alloy drill bit to complete the machining of the center hole, eccentric hole, and chamfer. At this point, the precision turning of the thin-walled workpiece of the heterogeneous rotating body is completed.

[0042] According to the precision machining method for turning thin-walled heterogeneous rotating parts provided by the present invention, the clamping force at the outer jaw and the inner support jaw is: Q for:

[0043]

[0044] In the formula, This is the clamping coefficient. K2 is the tool wear coefficient, selected based on the tool wear condition; K2 is the clamping power stability coefficient, used during external clamping. When internal support ; The coefficient of friction is used during semi-finish turning and finish turning. ; For axial cutting force, For tool material parameters, during semi-finish turning When precision turning ; The main cutting force, For tool material parameters, during semi-finish turning When precision turning .

[0045] The advantages and effects of this invention are:

[0046] 1. The special fixture for turning thin-walled parts of heterogeneous rotating bodies provided by the present invention adopts external clamping, internal support and rib plate limiting to support the thin-walled parts in four directions, reduce clamping and processing deformation, improve the dimensional accuracy and positional accuracy of the thin-walled parts, improve the dimensional consistency after processing, reduce the scrap rate of products and reduce processing costs.

[0047] 2. This invention enables multi-functional integrated fixture clamping, ensuring that the position of thin-walled parts is fixed during turning and greatly reducing clamping deformation, thus reducing machine tool vibration and tool deflection, and reducing the surface roughness of the machined parts.

[0048] 3. The inner and outer jaws and support discs involved in this invention can be changed and replaced according to the material and shape of the thin-walled parts. The clamping interchangeability is high and it can be applied to the clamping of different types of rotating thin-walled parts, effectively improving the efficiency of parts loading and unloading.

[0049] 4. The machining method provided by this invention is suitable for mass production. By reasonably matching the cutting speed, feed rate and depth of cut, the machining efficiency and machining accuracy are greatly improved. Attached Figure Description

[0050] Figure 1 This is a cross-sectional view of the turning fixture for a heterogeneous rotating thin-walled part according to an embodiment of the present invention;

[0051] Figure 2 This is a cross-sectional view of a conical two-stage telescopic hydraulic cylinder according to an embodiment of the present invention;

[0052] Figure 3 (1) is a right view of the annular three-claw inner support portion of an embodiment of the present invention. Figure 3 (2) is a cross-sectional view of AA;

[0053] Figure 4(1) It is a flexible support structure. Figure 4 (2) is the rigid support structure of the present invention;

[0054] Figure 5 This is a schematic diagram of the support plate according to an embodiment of the present invention. Figure 5 (1) is a circular disk, Figure 5 (2) It is an irregularly shaped disk;

[0055] Figure 6 This is a cross-sectional view of the workpiece according to an embodiment of the present invention;

[0056] Wherein: 1-Inner support claw; 2-Inner support slider; 3-Outer gripper; 4-Three-jaw chuck; 5-Chuck flange; 6-Conical hydraulic cylinder; 6-1-Slider groove; 6-2-Outer cover; 6-3-Conical outer cylinder barrel; 6-4-Tie rod connecting hole; 6-5-Annular spline; 7-Rear cylinder head; 8-Inner cylinder barrel; 9-Piston rod; 10-Guide sleeve; 11-Front cylinder head; 12-Connecting rod disc; 13-Connecting rod seat; 14-Connecting rod; 15-Support shaft; 16-Support disc; 17-Flexible support structure; 18-First-stage servo directional valve; 19-Second-stage servo directional valve; 20-First oil circuit; 21-Second oil circuit; 22-Third oil circuit. Detailed Implementation

[0057] To better understand the purpose, structure, and function of this invention, the following is combined with... Figures 1-6 The technical solution provided by this invention will be described in more detail below.

[0058] See Figures 1 to 6 The special turning fixture for heterogeneous rotating thin-walled parts provided in this embodiment of the invention adopts an inner wall positioning and a clamping method with joint support from the inner and outer walls and ribs, including a conical two-stage telescopic servo hydraulic system and an inner support module;

[0059] The conical two-stage telescopic servo hydraulic system includes a conical hydraulic cylinder 6. The conical hydraulic cylinder 6 has a primary chamber inside, and an inner cylinder 8 is slidably installed along the axial direction of the primary chamber. The inner cylinder 8 has a secondary chamber inside, and a piston rod 9 is slidably installed along the axial direction of the secondary chamber. A front cylinder cover 11 is installed at the right open end of the inner cylinder 8, and a central through hole is opened along the axial direction of the front cylinder cover 11. The right end of the piston rod 9 extends out through the central through hole.

[0060] The internal support module includes an internal wall support mechanism and a rib plate support mechanism;

[0061] The inner wall support mechanism is located at the right protruding end of the inner cylinder 8. The inner wall support mechanism includes three inner support claws 1, which are equidistantly distributed along the circumferential direction of the inner wall of the workpiece to support the inner wall of the workpiece.

[0062] The rib support mechanism is located at the right end of the piston rod 9. The rib support mechanism includes a support plate 16, which abuts against the rib of the workpiece to support the rib of the workpiece.

[0063] It also includes an external clamping module, which includes a three-jaw chuck 4 and three external jaws 3 equidistantly distributed along the circumference of the three-jaw chuck 4. The three external jaws 3 apply a centripetal clamping force to the outer wall of the workpiece to clamp the outer wall of the workpiece.

[0064] This invention achieves graded control under hydraulic drive through a two-stage telescopic servo hydraulic cylinder drive system, enabling simultaneous external clamping and internal support. This greatly reduces clamping deformation and cutting vibration, ensuring clamping stability and reliability while improving machining accuracy, making it suitable for high-speed cutting. The three modules—external clamping, internal wall support, and rib support—are independent of each other, resulting in a compact structure. The support force is easily controlled, and the disassembly of thin-walled parts is convenient and efficient, saving a significant amount of loading and unloading time for the mass production of thin-walled parts, effectively saving costs and improving equipment utilization.

[0065] in,

[0066] Please see the appendix Figure 1 In this embodiment of the invention, the conical two-stage telescopic servo hydraulic system includes a conical hydraulic cylinder 6, the conical hydraulic cylinder 6 having a primary chamber, and an inner cylinder 8 being slidably installed along the axial direction of the primary chamber;

[0067] Specifically, the external part of the conical two-stage telescopic servo hydraulic system is a conical hydraulic cylinder 6, which includes a conical outer cylinder 6-3. The conical outer cylinder 6-3 has a Morse taper structure and transitions to the inner hole of the machine tool spindle. It is connected to the pull rod through the left end pull rod connection hole 6-4 and extends out of the left end of the machine tool spindle for fixation. The right end is connected and fixed to other components on the right side through circumferential array bolts. The inner cylinder 8 is slidably installed inside the conical hydraulic cylinder 6. The left end of the inner cylinder 8 is a piston structure with multiple sealing rings.

[0068] It should be noted that the axial direction of the primary chamber is the left-right direction of the conical hydraulic cylinder 6;

[0069] Please continue reading the appendix. Figure 1 In this embodiment of the invention, the inner cylinder 8 has a secondary chamber, and a piston rod 9 is slidably installed along the axial direction of the secondary chamber. A front cylinder head 11 is installed at the right open end of the inner cylinder 8, and a central through hole is opened along the axial direction of the front cylinder head 11. The right end of the piston rod 9 extends out through the central through hole.

[0070] Specifically, the piston rod 9 is slidably installed inside the inner cylinder 8. The left end of the piston rod 9 is a piston structure with multiple sealing rings. The right end of the piston rod 9 extends through the middle through hole of the front cover 11. The right end of the inner cylinder 8 is fixedly connected to the front cylinder cover 11 by threads. The front cover 11 and the piston rod 9 are transitionally fitted, and multiple sealing rings are provided at the connection to prevent oil leakage.

[0071] It should be noted that the axial direction of the secondary chamber is the left-right direction of the inner cylinder 8.

[0072] The internal support module includes an internal wall support mechanism and a rib plate support mechanism; wherein...

[0073] Please see the appendix Figure 3 In this embodiment of the invention, in order to support the inner wall of the workpiece, the inner wall support mechanism is provided at the right protruding end of the inner cylinder 8. The inner wall support mechanism includes three inner support claws 1, and the three inner support claws 1 are equidistantly distributed along the circumferential direction of the inner wall of the workpiece to support the inner wall of the workpiece.

[0074] Please continue reading the appendix. Figure 1 The rib support mechanism is located at the right end of the piston rod 9. The rib support mechanism includes a support plate 16, which abuts against the rib of the workpiece to support the rib of the workpiece.

[0075] In some embodiments, the support disk 16 may be a circular disk or an irregularly shaped disk.

[0076] In some embodiments, please refer to the appendix. Figure 4 According to the clamping and processing requirements, it can be replaced with a flexible support structure 17, which is a universal joint. The purpose of this setting is that when the plane of the rib plate is not flat or the verticality is insufficient, the angle and position of the support plate can be adjusted by the universal joint so that the support plate and the rib plate can be in full contact to provide support for the rib plate.

[0077] Please continue reading the appendix. Figure 1 In this embodiment of the invention, in order to clamp the outer wall of the workpiece, an external clamping module is also included. The external clamping module includes a three-jaw chuck 4 and three external jaws 3 that are equidistantly distributed along the circumference of the three-jaw chuck 4. The three external jaws 3 apply a centripetal clamping force to the outer wall of the workpiece to clamp the outer wall of the workpiece. The three-jaw chuck 4 is bolted to the machine tool flange through the chuck flange 5, and the three-jaw chuck 4 rotates synchronously with the machine tool spindle.

[0078] According to the clamping requirements, use a constant force wrench to apply a centripetal clamping force to the outer jaw 3, and manually apply an external clamping force to the outer wall of the workpiece.

[0079] In this embodiment of the invention, the three outer grippers 3 are positioned corresponding to the three inner support grippers 1. With this arrangement, the outer grippers 3 and the inner support grippers 1 apply forces in opposite directions on both sides of the thin-walled part, thereby eliminating the function of clamping deformation.

[0080] Please see the appendix Figure 1 In this embodiment of the invention, in order to limit the axial position of the inner cylinder 8 and prevent the inner cylinder 8 from separating from the conical hydraulic cylinder 6, the protruding end of the inner cylinder 8 is interference-fitted with a guide sleeve 10, and the guide sleeve 10 is fixedly connected to the conical hydraulic cylinder 6 by bolts. A part of the guide sleeve 10 extends into the conical hydraulic cylinder 6. Specifically, the inner cylinder 8 is slidably installed inside the conical hydraulic cylinder 6, and the left end of the inner cylinder 8 is a piston structure with multiple sealing rings.

[0081] More specifically, a guide sleeve 10 is provided on the right side of the inner cylinder 8 and is fixed with an interference fit to the guide sleeve 10. At the same time, the guide sleeve 10 is fixedly connected to the right end of the conical hydraulic cylinder 6 by bolts, and the right end of the inner cylinder 8 is fixedly connected to the front cylinder head 11 by threads.

[0082] Please continue reading the appendix. Figure 1-2 In this embodiment of the invention, the inner cylinder 8 is provided with a circumferential array of annular splines 6-5 in the middle, and the inner wall of the conical hydraulic cylinder 6 is provided with a spline keyway that is clearance-fitted with the annular splines 6-5. The axial length of the spline keyway is greater than the axial length of the annular splines 6-5. This arrangement allows the conical hydraulic cylinder 6 and the inner cylinder 8 to rotate synchronously, while the inner cylinder 8 can move axially within the cavity of the conical hydraulic cylinder 6. The axial dimensions of the spline keyway and the annular splines 6-5 are different; the annular splines 6-5 are shorter, and the spline keyway is longer. The annular splines 6-5 are integral with the inner cylinder. The annular splines 6-5 are designed to allow the inner cylinder 8 to rotate with the outside while moving left and right within the primary chamber.

[0083] Please continue reading the appendix. Figure 1 In this embodiment of the invention, a rear cylinder cover 7 is provided at the end of the conical hydraulic cylinder 6 opposite to the guide sleeve 10, and the rear cylinder cover 7 is provided with an oil inlet / outlet port b and an oil inlet / outlet port a. Specifically, the left end of the conical hydraulic cylinder 6 is provided with a rear cylinder cover 7, which is connected and fixed to the conical hydraulic cylinder 6 by threads, and the rear cylinder cover 7 is provided with an oil inlet / outlet port a and an oil inlet / outlet port b.

[0084] It should be noted that the space inside the conical outer cylinder 6-3 is a primary chamber, and the left end of the inner cylinder 8 is a piston structure with multiple sealing rings, which divides the primary chamber into left and right chambers.

[0085] It should also be noted that the hollow structure on the right side of the inner cylinder 8 is a two-stage chamber, and the piston structure with multiple sealing rings at the left end of the piston rod 9 divides the two-stage chamber into left and right chambers.

[0086] The inner cylinder 8 has a piston structure on the left side, and the first-stage chamber is divided into a first-stage left chamber and a first-stage right chamber by the piston structure of the inner cylinder 8.

[0087] The piston rod 9 has a piston structure on its left side, and the secondary chamber is divided into a secondary left chamber and a secondary right chamber by the piston structure of the piston rod 9;

[0088] The inner wall of the inner cylinder 8 is provided with a first oil passage on the left side. One end of the first oil passage 20 is connected to the inlet / outlet b through a first-stage left chamber. A first-stage servo reversing valve 18 is provided at the connection between the first oil passage 20 and the first-stage left chamber. The other end of the first oil passage 20 is connected to the second-stage left chamber.

[0089] The inner wall of the conical hydraulic cylinder 6 is provided with a second oil passage 21 on the left side. One end of the second oil passage 21 is connected to the inlet / outlet a, and the other end of the second oil passage 21 is connected to the first-stage right chamber.

[0090] A third oil passage is provided on the right side of the inner wall of the conical hydraulic cylinder 6. One end of the third oil passage 22 is connected to the first-stage right chamber, and a second-stage servo reversing valve 19 is provided at the connection between the third oil passage 22 and the first-stage right chamber. The other end of the third oil passage 22 is connected to the second-stage right chamber.

[0091] Loading process: Oil is supplied through inlet / outlet b, and inlet / outlet a is opened. The first-stage servo directional valve 18 and the second-stage servo directional valve 19 are closed. Oil enters the left chamber of the first-stage chamber and exits the right chamber. The inner cylinder moves to the right. After the inner support claw is in place, the first-stage servo directional valve 18 is opened. At this time, inlet / outlet b continues to supply oil. The oil enters the left chamber of the second-stage chamber from the left chamber of the first-stage chamber. The piston rod moves to the right. The oil from the right chamber of the second-stage chamber flows into the right chamber of the first-stage chamber and then flows out from inlet / outlet a.

[0092] Unloading process: Oil is introduced through oil inlet / outlet a, oil inlet / outlet b is opened, and similarly, the inner cylinder retracts first, and after the secondary servo reversing valve 19 is opened, the piston rod 9 retracts.

[0093] Please see the appendix Figure 3 In this embodiment of the invention, in order to support the inner wall of the workpiece, the inner wall support mechanism includes a connecting rod disk 12, which is disposed on the right side of the front cylinder head 11. The connecting rod disk 12 has a central hole through which the piston rod 9 can extend. At least three connecting rod seats 13 are equidistantly arranged circumferentially on the right end face of the connecting rod disk 12. One end of two parallel connecting rods 14 is hinged and fixed on each connecting rod seat 13. An inner support slider 2 is hinged and fixed to the other end of every two connecting rods 14. Each inner support slider 2 is connected to a corresponding inner support claw 1. The clamping force is applied to the inner wall of the workpiece through the three inner support claws 3.

[0094] Specifically, the right end face of the front cover 11 is provided with a circumferential array of bolts to be connected and fixed to the connecting rod disk 12. Three connecting rod seats 13 are welded and fixed to the right end face of the connecting rod disk 12. The left ends of two parallel connecting rods 14 are hinged and fixed to each connecting rod seat 13. An inner support slider 2 is hinged and fixed to the right end of every two connecting rods 14. The inner support slider 2 is welded and connected to the rear end of the corresponding inner support claw 1. The clamping force is applied to the inner wall of the workpiece through the three inner support claws 1.

[0095] See appendix for further details. Figure 3 In this embodiment of the invention, to improve the stability of the inner support slider 2 during sliding, an outer cover 6-2 is installed on the right side of the conical hydraulic cylinder 6. At least three slider grooves 6-1 are formed radially on the right side of the outer cover 6-2, and the inner support slider 2 is slidably connected to the slider grooves 6-1. The outer end of the inner support slider 2 is slidably installed in the connecting rod slider groove 6-1 at the right end of the outer cover, allowing the inner support slider 2 to perform radial linear reciprocating motion within the connecting rod slider groove 6-1.

[0096] Understandably, when the spindle rotates, the two-stage telescopic servo hydraulic system, the inner support module, and the outer clamping module drive the workpiece to rotate together. The inner cylinder 8 and piston rod 9 in the two-stage telescopic servo hydraulic system can achieve axial left and right telescopic movement, which in turn drives the front cylinder head 11, connecting rod disc 12, and connecting rod seat 13 to achieve axial left and right movement. By driving the left end of the connecting rod 14 to move axially left and right, the right end of the connecting rod 14 achieves centrifugal and centripetal movement, which further drives the inner support slider 2 to achieve centrifugal and centripetal movement in the slider groove 6-1, and further drives the inner support slider 2 to achieve loading and unloading of the inner wall of the workpiece.

[0097] Furthermore, pressure sensors are installed at the contact positions between the inner support claw 1 and the support plate 16 and the workpiece. According to the clamping force requirements, during the loading stage, the oil inlet / outlet port b set on the rear cylinder cover 7 is the oil inlet. The first-stage servo reversing valve 18 is opened, and the oil enters the left chamber of the conical hydraulic cylinder 6, giving pressure to the left end face of the piston of the inner cylinder 8, pushing the inner cylinder 8 to move to the right along the axis, and then pushing the connecting rod plate 12 and the connecting rod 13 to move to the right. Under the action of the thrust, the right end of the connecting rod 14 opens, causing the inner support slider 2 to make centrifugal motion in the slider groove 6-1 until the target clamping force is reached at the inner support claw 1. The signal is fed back to the servo hydraulic system connected to the servo hydraulic drive system to stop the oil supply and close the first-stage servo reversing valve 18 to complete the clamping and positioning of the inner wall of the workpiece.

[0098] See appendix for further details. Figure 1In this embodiment of the invention, to support the ribs of the workpiece, the rib support mechanism includes a support disk 16. One end face of the support disk 16 abuts against the ribs of the workpiece, and a support shaft 15 is provided on the other end face of the support disk 16 in a vertical direction. One end of the support shaft 15 is connected to the support disk 16, and the other end of the support shaft 15 is connected to the piston rod 9. The central axes of the support shaft 15 and the piston rod 9 are on the same straight line. Specifically, the right end of the piston rod 9 is fixedly connected to the left end of the support shaft 15 by a thread, and the right end of the support shaft 15 is fixedly connected to the support disk 16 by a thread to achieve rib support for the workpiece.

[0099] In this embodiment of the invention, when supporting the workpiece rib, the secondary servo reversing valve 19 is opened, and oil enters the left chamber of the inner cylinder 8, applying pressure to the left end face of the piston rod 9, pushing the piston rod 9 to drive the support rod 15 to move to the right along the axial direction, thereby driving the support plate 16 to move to the right until the support plate 16 contacts the workpiece rib, thus realizing the support and clamping of the thin-walled part rib.

[0100] In some embodiments, due to the special characteristics of thin-walled parts with ribs, a support plate 16 is provided for rib support. When the support force requirement is large, the support plate 16 can be set as an electromagnet to achieve magnetic attraction and magnetic push, thereby achieving effective support.

[0101] This invention employs a four-in-one fixture to minimize clamping deformation, thereby reducing machining errors caused by such deformation. High-speed cutting technology enables efficient and high-precision cutting of heterogeneous rotating thin-walled parts. This reduces cutting forces and machining deformation, while the chips carry away a significant amount of cutting heat, resulting in a low workpiece temperature rise and suppressing thermal deformation. This effectively controls deformation and improves machining accuracy. It adapts to the requirements of mass production, reduces scrap rates, improves precision to meet machining requirements, increases clamping and machining efficiency, and reduces time costs, tool wear costs, cutting fluid usage and disposal costs, and scrap generation costs.

[0102] This invention also provides a precision machining method for turning heterogeneous thin-walled rotating parts. Using the aforementioned special turning fixture for heterogeneous thin-walled rotating parts, taking the turning of a heterogeneous thin-walled rotating part made of high-hardness, high-strength, low-thermal-conductivity, and difficult-to-machine material as an example, such as... Figures 4-6 As shown, it includes the following steps:

[0103] Step 1: Rough machining preparation. Determine the cutting parameters and tools based on the material properties, and determine the number of passes based on the machining allowance, as shown in Table 1.

[0104] Increasing the cutting speed can effectively reduce the cutting force, thereby reducing machining deformation. At the same time, it can allow the cutting heat to be carried away by the chips, greatly reducing the workpiece temperature and thus reducing thermal deformation. However, excessively high cutting speeds will accelerate tool wear, making it impossible to guarantee the workpiece's machining accuracy and surface quality, while increasing machining costs and reducing machining efficiency.

[0105] The cutting speed is 100m / min to 250m / min, the feed rate is no more than 0.15mm / r, and the cutting depth is 0.1 to 0.3mm. This ensures that the cutting deformation is within the required range and allows for long-term stable cutting, guaranteeing the machining accuracy and surface roughness requirements.

[0106]

[0107] Step 2: Clamp the workpiece at end B. Select a circular support plate 16. Extend the inner cylinder 8 to open the inner support claw 1 and clamp the inner wall of end B of the workpiece. Extend the piston rod 9 to make the support plate 16 contact the workpiece rib and provide support force. Then use a constant torque wrench to move the outer claw 3 of the three-jaw chuck 4 toward the center to clamp the outer wall of end B of the workpiece.

[0108] The specific steps are as follows:

[0109] Step 21: The two-stage telescopic servo hydraulic drive system is working. The front end of the inner cylinder 8 extends out and, through the joint action of the connecting rod disc 12 and the connecting rod 14, pushes the inner support slider 2 and the inner support claw 1 to move away from the center until the force between the inner support claw 1 and the inner wall of the workpiece B end reaches the set target value. This target value must be greater than the optimal inner support clamping force. The set target value is determined by clamping force calculation.

[0110] Step 22: The piston rod 9 pushes the support plate 16 to move towards the rib side of the workpiece, contacting the workpiece rib and providing support force; the specific clamping force parameters are accurately calculated according to the clamping requirements using the clamping force calculation formulas at the support plate 16 and the inner support claw 1; the support plate 16 is a circular plate, and when the pressure sensor at the support plate 16 and the inner support claw 1 detects the target pressure, the secondary servo reversing valve 19 closes and stops oil supply;

[0111] Step 23: Use a constant torque wrench to move the outer jaw 3 of the three-jaw chuck 4 toward the center to clamp the outer wall of workpiece B.

[0112] Step 3: Semi-finish machining of end A, with a cutting speed of 100m / min to 150m / min, a feed rate of 0.1mm / r to 0.15mm / r, a cutting depth of 0.1mm to 0.2mm, and a allowance of less than 0.2mm. Use a 0.4mm carbide coated tool to machine the outer wall and end face, and use a 0.8mm carbide coated tool to machine the inner wall and ribs.

[0113] Step 4: Finish machining end A. The cutting speed is 150m / min to 200m / min, the feed rate is no more than 0.1mm / r, the cutting depth is 0.05 to 0.1mm, and the cutting is done in multiple passes. Use a R0.4mm or R0.8mm carbide coated tool to machine the outer wall and end face, and use a R0.4mm or R0.8mm carbide coated tool to machine the inner wall and ribs.

[0114] Step 5: Inspect and compensate for the finishing of the outer and inner walls of end A. The cutting speed is 200m / min~300m / min, the feed rate is no more than 0.05mm / r, the cutting depth is less than 0.05mm, and a R0.8mm carbide coated tool is used.

[0115] Step 6: Disassemble the workpiece, clamp the workpiece at end A, select the irregular-shaped disk for support disk 16 according to the processing requirements, and the clamping operation steps are the same as in step 2.

[0116] Step 7: Semi-finish workpiece B end, select a cutting speed of 100m / min~150m / min, a feed rate of 0.1mm / r~0.15mm / r, a cutting depth of 0.1~0.2mm, leaving a allowance of less than 0.2mm, use an R0.8mm carbide coated tool to machine the end face and outer wall, and use an R0.4mm carbide coated tool to machine the inner wall and rib plate;

[0117] Step 8: Finish machining end B of the workpiece. Select a cutting speed of 150m / min to 200m / min, a feed rate of no more than 0.1mm / r, a cutting depth of 0.05 to 0.1mm, and perform multiple passes. Use a R0.4mm or R0.8mm carbide coated tool to machine the end face and outer wall, and use a R0.4mm or R0.8mm carbide coated tool to machine the inner wall and ribs.

[0118] Step 9: Inspect and compensate for the finishing of the outer and inner walls of end B. The cutting speed is 200m / min~300m / min, the feed rate is no more than 0.05mm / r, the depth of cut is less than 0.05mm, and a R0.8mm carbide coated tool is used.

[0119] Step 10: Disassemble the workpiece. The support plate 16 is a non-circular plate. The workpiece B end is clamped. The spindle speed is 1000-8000 r / min and the feed rate is no more than 0.15 mm / r. The center hole, eccentric hole and chamfer are processed by using an alloy drill bit. At this point, the precision turning of the non-circular rotating thin-walled workpiece is completed.

[0120] According to the experimental results, the clamping support force P at the 16 points of the support plate is 300~600N.

[0121] The clamping force at the outer gripper 3 and the inner support gripper 1. Q for:

[0122]

[0123] In the formula, This is the clamping coefficient. K2 is the tool wear coefficient, selected based on the tool wear condition; K2 is the clamping power stability coefficient, used during external clamping. When internal support ; The coefficient of friction is used during semi-finish turning and finish turning. ; For axial cutting force, For tool material parameters, during semi-finish turning When precision turning ; The main cutting force, For tool material parameters, during semi-finish turning When precision turning .

[0124] The above description is only a partial embodiment of the present invention, not all embodiments. Any equivalent changes to the technical solutions of the present invention made by those skilled in the art through reading the present invention specification are covered by the claims of the present invention.

Claims

1. A special turning fixture for heterogeneous rotating thin-walled parts, characterized in that, include: A conical two-stage telescopic servo hydraulic system includes a conical hydraulic cylinder. The conical hydraulic cylinder has a primary chamber, and an inner cylinder is slidably installed along the axial direction of the primary chamber. The inner cylinder has a secondary chamber, and a piston rod is slidably installed along the axial direction of the secondary chamber. A front cylinder cover is installed at the right open end of the inner cylinder, and a central through hole is opened along the axial direction of the front cylinder cover. The right end of the piston rod extends out through the central through hole. An internal support module, the internal support module including an inner wall support mechanism and a rib support mechanism; The inner wall support mechanism is located at the right protruding end of the inner cylinder. The inner wall support mechanism includes three inner support claws, which are equidistantly distributed along the circumferential direction of the inner wall of the workpiece to support the inner wall of the workpiece. The rib support mechanism is located at the right end of the piston rod. The rib support mechanism includes a support plate, which abuts against the rib of the workpiece to support the rib of the workpiece. An external clamping module includes a three-jaw chuck and three external jaws equidistantly distributed along the circumference of the three-jaw chuck. The three external jaws apply a centripetal clamping force to the outer wall of the workpiece to clamp the outer wall of the workpiece. The inner wall support mechanism includes a connecting rod disc, which is located on the right side of the front cylinder head. The connecting rod disc has a central hole through which the piston rod can extend. At least three connecting rod seats are equidistantly arranged on the right end face of the connecting rod disc in the circumferential direction. One end of two parallel connecting rods is hinged and fixed on each connecting rod seat. An inner support slider is hinged and fixed on the other end of every two connecting rods. Each inner support slider is connected to a corresponding inner support claw. A clamping force is applied to the inner wall of the workpiece through the three inner support claws. The conical hydraulic cylinder is equipped with an outer cover on its right side. At least three connecting rod slider grooves are formed on the right side of the outer cover in the radial direction. The inner support slider is slidably connected to the connecting rod slider groove.

2. The special turning fixture for heterogeneous rotating thin-walled parts according to claim 1, characterized in that: The conical hydraulic cylinder includes a conical outer cylinder with a Morse taper structure, which transitions into the inner bore of the machine tool spindle and is connected to the machine tool tie rod through the left end tie rod connection hole.

3. The special turning fixture for heterogeneous rotating thin-walled parts according to claim 1, characterized in that: The three outer grippers correspond to the three inner support grippers in position.

4. The special turning fixture for heterogeneous rotating thin-walled parts according to claim 1, characterized in that: The right protruding end of the inner cylinder is interference-fitted with a guide sleeve, and the guide sleeve is fixedly connected to the conical hydraulic cylinder by bolts, with a portion of the guide sleeve extending into the conical hydraulic cylinder; The inner cylinder is provided with a circumferential array of annular splines in the middle, and the inner wall of the conical hydraulic cylinder is provided with a spline keyway that is clearance-fitted with the annular splines. The axial length of the spline keyway is greater than the axial length of the annular splines.

5. The special turning fixture for heterogeneous rotating thin-walled parts according to claim 4, characterized in that: The conical hydraulic cylinder is provided with a rear cylinder cover on the left side, and the rear cylinder cover is provided with an oil inlet / outlet b and an oil inlet / outlet a; The inner cylinder has a piston structure on the left side, and the primary chamber is divided into a primary left chamber and a primary right chamber by the piston structure of the inner cylinder. The piston rod has a piston structure on its left side, and the secondary chamber is divided into a secondary left chamber and a secondary right chamber by the piston structure of the piston rod; The inner wall of the inner cylinder is provided with a first oil passage on the left side. One end of the first oil passage is connected to the oil inlet / outlet b through a first-stage left chamber. A first-stage servo reversing valve is provided at the connection between the first oil passage and the first-stage left chamber. The other end of the first oil passage is connected to the second-stage left chamber. A second oil passage is provided on the left side of the inner wall of the conical hydraulic cylinder. One end of the second oil passage is connected to the inlet / outlet a, and the other end of the second oil passage is connected to the first-stage right chamber. A third oil passage is provided on the right side of the inner wall of the conical hydraulic cylinder. One end of the third oil passage is connected to the first-stage right chamber, and a second-stage servo directional valve is provided at the connection between the third oil passage and the first-stage right chamber. The other end of the third oil passage is connected to the second-stage right chamber. Loading process: Oil is supplied through inlet / outlet b, oil inlet / outlet a is opened, the first-stage servo directional valve and the second-stage servo directional valve are closed, oil enters the left chamber of the first-stage chamber and exits the right chamber, the inner cylinder moves to the right, after the inner support claw is in place, the first-stage servo directional valve is opened, at this time oil supply continues through inlet / outlet b, oil enters the left chamber of the second-stage chamber from the left chamber of the first-stage chamber, the piston rod moves to the right, oil exits the right chamber of the second-stage chamber and flows into the right chamber of the first-stage chamber and then flows out through inlet / outlet a; Unloading process: Oil is introduced through inlet / outlet a, and inlet / outlet b is opened. Similarly, the inner cylinder retracts first, and the piston rod retracts after the secondary servo reversing valve is opened.

6. The special turning fixture for heterogeneous rotating thin-walled parts according to claim 1, characterized in that: The rib support mechanism includes a support plate, one end face of which abuts against the rib of the workpiece, and the other end face of the support plate is provided with a support shaft in a vertical direction. One end of the support shaft is connected to the support plate, and the other end of the support shaft is connected to the piston rod. The central axes of the support shaft and the piston rod are on the same straight line.

7. A precision machining method for turning a heterogeneous rotating thin-walled part, using a special turning fixture for heterogeneous rotating thin-walled parts as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Rough machining preparation. Determine the cutting parameters and tools based on the material properties, and determine the number of passes based on the machining allowance. Step 2: Clamp the workpiece at end B. Select a circular support plate. Extend the inner cylinder to open the inner support claws and clamp the inner wall of end A of the workpiece. Extend the piston rod to make the circular plate contact the workpiece rib and provide support force. Then use a constant torque wrench to move the outer jaws of the three-jaw chuck towards the center to clamp the outer wall of end B of the workpiece. Step 3: Semi-finish machining of end A, with a cutting speed of 100m / min to 150m / min, a feed rate of 0.1mm / r to 0.15mm / r, a cutting depth of 0.1mm to 0.2mm, and a allowance of less than 0.2mm. Use a 0.4mm carbide coated tool to machine the outer wall and end face, and use a 0.8mm carbide coated tool to machine the inner wall and ribs. Step 4: Finish machining end A. The cutting speed is 150m / min to 200m / min, the feed rate is no more than 0.1mm / r, the cutting depth is 0.05 to 0.1mm, and the cutting is done in multiple passes. Use a R0.4mm or R0.8mm carbide coated tool to machine the outer wall and end face, and use a R0.4mm or R0.8mm carbide coated tool to machine the inner wall and ribs. Step 5: Inspect and compensate for the finishing of the outer and inner walls of end A. The cutting speed is 200m / min~300m / min, the feed rate is no more than 0.05mm / r, the cutting depth is less than 0.05mm, and a R0.8mm carbide coated tool is used. Step 6: Disassemble the workpiece, clamp the workpiece at end A, select the irregular-shaped disk according to the processing requirements, and the clamping operation steps are the same as in Step 2; Step 7: Semi-finish workpiece B end, select a cutting speed of 100m / min~150m / min, a feed rate of 0.1mm / r~0.15mm / r, a cutting depth of 0.1~0.2mm, leaving a allowance of less than 0.2mm, use an R0.8mm carbide coated tool to machine the end face and outer wall, and use an R0.4mm carbide coated tool to machine the inner wall and rib plate; Step 8: Finish machining end B of the workpiece. Select a cutting speed of 150m / min to 200m / min, a feed rate of no more than 0.1mm / r, a cutting depth of 0.05 to 0.1mm, and perform multiple passes. Use a R0.4mm or R0.8mm carbide coated tool to machine the end face and outer wall, and use a R0.4mm or R0.8mm carbide coated tool to machine the inner wall and ribs. Step 9: Inspect and compensate for the finishing of the outer and inner walls of end B. The cutting speed is 200m / min~300m / min, the feed rate is no more than 0.05mm / r, the depth of cut is less than 0.05mm, and a R0.8mm carbide coated tool is used. Step 10: The spindle speed is 1000-8000 r / min, and the feed rate is no more than 0.15 mm / r. Use an alloy drill bit to complete the machining of the center hole, eccentric hole, and chamfer. At this point, the precision turning of the thin-walled workpiece of the heterogeneous rotating body is completed.

8. The precision machining method for turning thin-walled heterogeneous rotating bodies according to claim 7, characterized in that: The clamping force at the outer gripper and inner support gripper Q for: In the formula, This is the clamping coefficient. This is the tool wear coefficient, which is selected based on the tool wear condition. To ensure the clamping dynamic stability coefficient, external clamping is required. When internal support ; The coefficient of friction is used during semi-finish turning and finish turning. ; For axial cutting force, For tool material parameters, during semi-finish turning When precision turning ; The main cutting force, For tool material parameters, during semi-finish turning When precision turning .

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