A servo pre-press high-precision machining equipment spindle guide module

Abstract

The present application belongs to the field of processing equipment, and proposes a follow-up pre-press high-precision processing equipment main shaft guide module, which comprises an inner guide and an outer drill sleeve. The outer drill sleeve plays a guiding role in the feeding movement, and the inner guide plays a guiding role in the rotating movement. A vibration-proof ring is arranged between the inner and outer guides to make the inner guide and the outer drill sleeve have an interference fit, eliminate the gap, have high pre-press rigidity, and make the entire main shaft guide module have no radial gap, good precision and vibration reduction performance. The inner guide structure is connected with the automatic feeding processing equipment main shaft, the rolling bearing and the bearing guide sleeve have an interference fit, the bearing inner ring and the guide shaft have an interference fit, and the vibration-proof ring on the bearing outer sleeve and the guide drill sleeve have an interference fit, so that the rigidity is high. The module cooperates with other components of the automatic feeding processing equipment to realize the guiding function during drilling processing. The module ensures the rotation accuracy of the main shaft, increases the rigidity, reduces the vibration in the tool processing process, and further ensures the accuracy of reaming and the quality of the hole wall, greatly improving the processing precision and stability.

Description

Technical Field

[0001] This invention belongs to the field of processing equipment and relates to a spindle guide module for a high-precision machining equipment with follow-up preloading. Background Technology

[0002] Aircraft assembly involves numerous assembly holes for connecting parts, with stringent precision and quality requirements. There are three main hole-making methods: manual, semi-automatic, and fully automatic. Manual hole-making uses handheld pneumatic drills, drill bushings, and cutting tools. Semi-automatic hole-making typically uses automatic feed machining equipment with matching cutting tools and guide bushings. Automatic hole-making utilizes robots, drilling and riveting machines, and other automated equipment. With the widespread use of new titanium alloys, composite materials, and high-hardness, high-strength steels in aircraft manufacturing, and the increasing demands for precision and efficiency in aircraft assembly processes, traditional manual hole-making is gradually being replaced by semi-automatic and fully automatic equipment. Automatic feed machining equipment offers advantages over robots and drilling and riveting machines, including smaller hole-making space requirements, simpler operation, and lower tooling costs, and is increasingly being adopted in aircraft assembly processes involving numerous in-situ machining and assembly scenarios.

[0003] Typically, machining equipment uses rigid spindles, and their radial runout affects hole accuracy, quality, and stability. Automatic feed machining equipment, on the other hand, uses floating spindles or low-precision, weakly rigid spindles, providing only the circumferential rotational power for the tool. The tools used differ from those used in conventional machining equipment. Automatic feed machining equipment often ensures tool position and rotation accuracy through the fit between the spindle and guide bushing. The fit between the spindle and guide bushing is a clearance fit, constantly changing with wear. Simultaneously, sliding friction and collisions occur between them, resulting in low spindle rotational and linear motion accuracy and poor stability. Therefore, automatic feed machining equipment is currently only used for processes requiring IT10-level hole accuracy and cannot achieve IT8-level final hole accuracy, still requiring subsequent processes. Thus, the accuracy and stability of the spindle during operation are key factors determining hole accuracy and efficiency.

[0004] Currently, the automatic feed machining equipment and automatic drilling technology used in China's aircraft assembly field are all imported from abroad. Domestic research on the application technology of automatic feed machining equipment and the supporting cutting tools and drill bushings that affect its drilling accuracy is limited. ADU (Automatic Ductless Drilling) application technology has long relied on foreign tool suppliers. Domestic research started relatively late. Yang Xinliang et al. of AVIC General Aircraft South China Aircraft Industry Co., Ltd. invented "A Machining Device for Aircraft Wing-Fuselage Connection Holes," patent number "ZL202223047466.6," which includes an automatic feed drill, a drill jig, and a boring bar. The two ends of the boring bar are connected to the automatic feed drill and tool guide holes, respectively. With the cooperation of the automatic feed drill and the tool guide holes, a suitable rotational speed and feed rate are selected for machining. The spindle is externally fitted with a drill bushing. During drilling, the tool runout is large, and it is easily affected by chips during operation, which is detrimental to the stable operation of the spindle. Wang Fujie and others from Dalian University of Technology invented "a modular micro-pecking device for automatic feed drilling", patent number ZL201810964769.3. The device uses standard angular contact ball bearings and spline nuts to realize the reciprocating motion of the spindle, but the overall structure has a long chain of dimensions, high assembly requirements, and is prone to low end precision.

[0005] In summary, to ensure the hole diameter accuracy of miniaturized automatic feeding machining equipment for processing various materials, it is necessary to develop a guiding module with high guiding accuracy, high rigidity, and good spindle stability to meet the high-precision and high-efficiency hole-making requirements of aerospace equipment. Summary of the Invention

[0006] This invention addresses the high-precision machining needs of miniaturized automatic feed machining equipment by developing a follow-up preload high-precision machining equipment spindle guide module. This module comprises an inner guide and an outer guide. The inner guide uses a pair of angular contact bearings to ensure spindle rotation accuracy, and the guide structure has high straightness. A preload structure on the outer side of the inner guide structure ensures high-precision fit between the inner and outer guide structures, thereby guaranteeing high-precision linear motion of the inner guide within the outer guide. During drilling, the inner guide moves synchronously with the tool, ensuring that the spindle rigidity and rotation accuracy remain unchanged with spindle movement, exhibiting high stability and achieving high-precision guidance for spindle rotation and feed motion.

[0007] The technical solution of this invention:

[0008] A spindle guide module for a high-precision machining equipment with servo preload includes an inner guide and an outer drill sleeve;

[0009] The inner guide includes a guide shaft preload nut 1, a vibration damping ring A2, a bearing outer guide sleeve 3, a rolling bearing A4, a sealing ring A5, a rolling bearing B6, a bearing outer guide sleeve retaining ring 7, a sealing ring B8, a vibration damping ring B9, a main spindle guide front end retaining ring 10, a guide shaft 11, and a drilling cylindrical head screw 12;

[0010] The outer drill sleeve includes a guide drill sleeve 13;

[0011] Rolling bearing A4 and rolling bearing B6 are respectively installed in the stepped holes on the left and right sides of the bearing outer guide sleeve 3, and are interference-fitted with the bearing outer guide sleeve 3; the bearing outer guide sleeve retaining ring 7 is close to the rolling bearing B6, separating the rolling bearing B6 from the sealing ring B8 to prevent external chips and oil from entering.

[0012] The stepped rear end face of the guide shaft 11 has an annular groove for installing the sealing ring B8, and four evenly distributed threaded holes are opened on its front end face. The main shaft guide front end retaining ring 10 also has four threaded holes, which are connected to the stepped front end face of the guide shaft 11 by four drilled cylindrical head screws 12. The stepped rear end face of the guide shaft 11 is connected to the bearing outer guide sleeve retaining ring 7. The thin end of the guide shaft 11 passes through the rolling bearing B6 and the rolling bearing A4 and extends out, and is interference-fitted with the rolling bearing B6 and the rolling bearing A4. There is an external thread at the rear end of the guide shaft 11, and the guide shaft preload nut 1 provides preload force to the shaft system by engaging with the guide shaft 11 through the external thread.

[0013] Four sealing rings A5 are installed in the outer annular groove of the bearing outer guide sleeve 3 to prevent small chips from entering, store lubricating oil, and provide a certain damping to achieve vibration reduction. Anti-vibration rings A2 and B9 are made of materials with low elastic modulus and low coefficient of friction with steel. They are installed on both sides of the bearing outer guide sleeve 3 and fixed by adhesive bonding. The outer diameter of anti-vibration rings A2 and B9 is larger than the inner diameter of the guide drill sleeve 13. They are interference-fitted with the bearing outer guide sleeve 3 and the guide drill sleeve 13, respectively, and there is a preload between them. The anti-vibration rings A2 and B9 and the bearing outer guide sleeve 3 form an integral whole and can slide freely in the inner hole of the guide drill sleeve 13, thereby ensuring the overall rigidity, improving the dynamic characteristics of the overall spindle, and avoiding severe vibration during machining.

[0014] The beneficial effects of this invention are as follows: This invention provides a spindle guide module for a high-precision machining equipment with follow-up preload. The spindle extends from the front end of the machine body to transmit rotational and feed motions. The inner guide structure is connected to the front end shaft of the machine body via threads. The inner guide structure cooperates with the outer drill sleeve to guide linear motion. The rolling bearing in the inner guide cooperates with the outer guide sleeve 3, and the inner ring of the bearing cooperates with the guide shaft 11 to achieve high precision of spindle rotation. Four sealing rings A5 are installed in the outer annular groove of the outer guide sleeve 3 to prevent small chips from entering, store lubricating oil, and provide a certain damping to achieve vibration reduction. An anti-vibration ring is provided between the outer guide sleeve 3 and the guide drill sleeve 13. The anti-vibration ring is interference-fitted with both, and there is preload between them to achieve high precision of spindle linear motion, while having good vibration reduction performance. This ensures the accuracy of the reaming and the quality of the hole wall, and greatly improves the machining accuracy and stability. Attached Figure Description

[0015] Fig. 1 This is an exploded view of the spindle guide module of a high-precision machining equipment with follow-up preloading, as described in this invention.

[0016] Fig. 2 This invention provides a cross-sectional view of the assembly of a spindle guide module for a high-precision machining equipment with servo preloading.

[0017] Fig. 3 This is an overall diagram of the present invention in conjunction with an automatic feed machining equipment, wherein (a) is a schematic diagram of the drill body structure, and (b) is a schematic diagram of the present invention in conjunction with the automatic feed machining equipment.

[0018] In the diagram: 1. Guide shaft preload nut, 2. Vibration damping ring A, 3. Bearing outer guide sleeve, 4. Rolling bearing A, 5. Sealing ring A, 6. Rolling bearing B, 7. Bearing outer guide sleeve retaining ring, 8. Sealing ring B, 9. Vibration damping ring B, 10. Spindle guide front end retaining ring, 11. Guide shaft, 12. Drilling cylindrical head screw, 13. Guide drill bushing, 14. Cutting tool, 15. Drill body. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0020] Example 1

[0021] refer to Figs. 1-3 A spindle guide module for high-precision machining equipment with follow-up preloading, comprising:

[0022] like Fig. 1 The spindle guide module of a high-precision machining equipment with follow-up preload is shown. The device includes a guide shaft preload nut 1, a vibration damping ring A2, a bearing outer guide sleeve 3, a rolling bearing A4, a sealing ring A5, a rolling bearing B6, a bearing outer guide sleeve retaining ring 7, a sealing ring B8, a vibration damping ring B9, a spindle guide front end retaining ring 10, a guide shaft 11, a drilling cylindrical head screw 12, and a guide drill sleeve 13.

[0023] In this embodiment, four sealing rings A5 are installed in the outer annular groove of the bearing outer guide sleeve 3. The outer shell of the bearing outer guide sleeve 3 has steps on both sides. Anti-vibration rings A2 and B9 are installed on both sides of the bearing outer guide sleeve and fixed with adhesive. The anti-vibration rings are interference-fitted with the guide drill sleeve 13. Rolling bearings A4 and B6 are respectively installed in the steps on the left and right sides of the inner side of the bearing outer guide sleeve and are interference-fitted with it. The bearing outer guide sleeve retaining ring 7 is tightly attached to the rolling bearing B6, separating it from the sealing ring B8. The guide shaft 11 has steps... The rear end face has an annular groove for installing the sealing ring B8, and four evenly distributed threaded holes are opened on its end face. The front retaining ring 10 of the main spindle guide also has four threaded holes. It is connected to the stepped front end face of the guide shaft 11 through four drilled cylindrical head screws 12. The stepped rear end face is connected to the bearing outer guide sleeve retaining ring 7. The thin end of the guide shaft passes through the rolling bearings B and A and extends out, and is interference-fitted with the two bearings. There is an external thread at the rear end of the guide shaft 11. The guide shaft preload nut 1 is connected to the rear end of the guide shaft through the external thread to apply preload force to the bearing. Finally, the bearing outer guide sleeve 3 is interference-fitted into the guide drill sleeve 13 to complete the assembly.

[0024] During operation, the outer bearing guide sleeve 3 is restricted from rotation, and the spindle extends from the front end of the machine body to achieve rotation and feed motion. The rear end of the guide shaft 11 is connected to the front end shaft of the machine body to achieve high-precision positioning of the guide shaft movement. The front end of the guide shaft 11 has a threaded groove to clamp different cutting tools. The front end of the guide drill sleeve 13 is installed in the auxiliary fixture, and its stepped surface controls the distance between the cutting tool and the workpiece within a suitable range. Through other modules, the guide shaft 11 is driven to rotate and feed, thereby driving the cutting tool to perform drilling on the target workpiece. This achieves the overall guiding function; the rolling bearing is interference-fitted with the outer guide sleeve 3, the inner ring of the bearing is interference-fitted with the guide shaft 11, and the anti-vibration rings A2 and B9 are interference-fitted with the outer guide sleeve 3 and the guide drill sleeve 13. There is preload between each pair. The anti-vibration rings A2 and B9 and the outer guide sleeve 3 form an integral whole and can slide freely in the inner hole of the guide drill sleeve, ensuring the accuracy and rigidity of the spindle and having good vibration reduction performance. This, in turn, ensures the accuracy of the reaming and the quality of the hole wall, greatly improving the accuracy and stability of the machining.

Claims

1. A spindle guide module for a high-precision machining equipment with follow-up preloading, characterized in that, The spindle guide module of the follow-up preload high-precision machining equipment includes an inner guide and an outer drill sleeve; The inner guide includes a guide shaft preload nut (1), anti-vibration ring A (2), bearing outer guide sleeve (3), rolling bearing A (4), sealing ring A (5), rolling bearing B (6), bearing outer guide sleeve retaining ring (7), sealing ring B (8), anti-vibration ring B (9), main spindle guide front end retaining ring (10), guide shaft (11), and drilling cylindrical head screw (12). The outer drill sleeve includes a guide drill sleeve (13); Rolling bearing A (4) and rolling bearing B (6) are respectively installed in the stepped holes on the left and right sides of the bearing outer guide sleeve (3) and are interference-fitted with the bearing outer guide sleeve (3); the bearing outer guide sleeve retaining ring (7) is close to the rolling bearing B (6) to separate the rolling bearing B (6) from the sealing ring B (8) to prevent external chips and oil from entering. The stepped rear end face of the guide shaft (11) has an annular groove for installing the sealing ring B (8), and four evenly distributed threaded holes are opened on its front end face. The main shaft guide front end retaining ring (10) also has four threaded holes. It is connected to the stepped front end face of the guide shaft (11) by four drilled cylindrical head screws (12). The stepped rear end face of the guide shaft (11) is connected to the bearing outer guide sleeve retaining ring (7). The thin end of the guide shaft (11) passes through the rolling bearing B (6) and the rolling bearing A (4) and extends out, and is interference-fitted with the rolling bearing B (6) and the rolling bearing A (4). There is an external thread at the rear end of the guide shaft (11). The guide shaft preload nut (1) is connected to the guide shaft (11) through the external thread to provide preload force for the shaft system. Four sealing rings A (5) are installed in the outer annular groove of the bearing outer guide sleeve (3) to block small chips from entering, store lubricating oil and provide a certain damping to achieve vibration reduction effect; anti-vibration rings A (2) and B (9) are made of materials with low elastic modulus and low friction coefficient with steel, and are installed on both sides of the bearing outer guide sleeve (3) and fixed by adhesive bonding; among them, the outer diameter of anti-vibration rings A (2) and B (9) is larger than the inner diameter of the guide drill sleeve (13). Anti-vibration rings A (2) and B (9) are respectively interference fit with the bearing outer guide sleeve (3) and the guide drill sleeve (13), and there is a pre-pressure between them. Anti-vibration rings A (2) and B (9) and the bearing outer guide sleeve (3) form an integral whole and can slide freely in the inner hole of the guide drill sleeve (13), thereby ensuring the overall rigidity, thereby improving the dynamic characteristics of the overall spindle and avoiding severe vibration during the machining process.

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