CN114871822A

CN114871822A - Centrifugal force-free cutting device

Info

Publication number: CN114871822A
Application number: CN202210462551.4A
Authority: CN
Inventors: 唐伟; 赖颂文; 梁潮淋; 肖耘亚; 林梓灿; 郭朝浩; 林永浩; 张楷铎; 神翠楠; 唐溢成; 叶木强; 温汝良; 古伟; 叶际英
Original assignee: Shaoguan University
Current assignee: Shaoguan University
Priority date: 2022-04-28
Filing date: 2022-04-28
Publication date: 2022-08-09
Anticipated expiration: 2042-04-28
Also published as: DE102023110674A1; CN114871822B

Abstract

The invention provides a centrifugal force-free cutting device, belongs to the technical field of machining, and is mainly used for turning a shaft with weak rigidity, namely a slender shaft. The cutting device is arranged on the rack and comprises a main shaft, a cutting mechanism positioned at the front end of the main shaft and a driving mechanism positioned at the rear end of the main shaft and used for driving the main shaft to rotate; the main shaft comprises an inner shaft and an outer shaft which are rotationally connected and respectively driven by an inner shaft motor and an outer shaft motor; the cutting structure is driven by an outer shaft to perform circumferential cutting, and the relative differential motion of the inner shaft and the outer shaft is synthesized to realize the radial feed of the cutter. The centrifugal force-free cutting device provided by the invention can reduce the processing deformation of the weak rigidity shaft, reduce the influence of the centrifugal force on the processing process, and simultaneously improve the processing quality and the processing efficiency of the weak rigidity shaft; the processing of the weak rigidity shaft is more intelligent and flexible, the operation difficulty of the processing of the weak rigidity shaft is reduced, the technical requirements on operators are reduced, and the processing level of shaft parts is improved.

Description

Centrifugal force-free cutting device

Technical Field

The invention relates to the technical field of machining, in particular to a centrifugal force-free cutting device for a weak-rigidity shaft.

Background

In machining, turning machines are the most widely used, accounting for about 50% of the total number of the machine tools, and shaft parts are the most common type in turning. The weak-rigidity shaft is one of common shaft parts, such as a screw rod, a transmission shaft and the like, and belongs to shaft parts difficult to machine. The elongated shaft is a typical weak stiffness shaft, and the definition of the elongated shaft is as follows: the ratio of the length to the diameter of the shaft is greater than 25 (i.e., L/D > 25). The slender shaft is usually processed by turning an outer circle, turning a step, turning a thread and the like. In the processing of the slender shaft, the instability caused by the centrifugal force can deform and vibrate a workpiece, and the processing precision and the surface quality of the workpiece are reduced, so that the assembly precision and the use precision of the whole machine are reduced.

The traditional slender shaft processing method generally adopts a lathe to process the slender shaft by clamping and jacking the slender shaft and matching with a center frame or a follow rest. The method using the center frame has the defects of increased processing times, high difficulty in controlling the clamping force, incapability of neglecting the centrifugal force and low processing efficiency. And the follow rest is used for processing the slender shaft, the follow rest is easy to contact with the excircle of the shaft too tightly or too loosely, the phenomenon of tool vibration occurs, and the processing quality is influenced due to the defects of bamboo joint shape, multi-prism shape and the like.

In order to solve the above problems, some scholars have improved the slender shaft process. On the basis of traditional numerical control machining, linear interpolation and circular interpolation are combined to eliminate defects of conical shapes and drum shapes, and machining quality is improved. However, the method is only suitable for numerical control machines, and interpolation functions of numerical control machines of different brands are different, so that the application range is narrow. Li dawn boat etc. have designed a magnetic force follow rest, have solved the not enough problem of traditional follow rest contact, and this magnetic force follow rest can effectively reduce work piece processing vibration through the experiment. But this magnetic force follower rest can't avoid the problem that follower rest machining efficiency is low. The method for reversely turning the slender shaft based on the pull-clamping method is deeply researched by Wannan and the like, and the simulation analysis method is adopted to verify the method, so that the bending deformation and the vibration of the slender shaft can be effectively reduced. But the method cannot avoid the influence caused by the defects of the traditional single-tool turning. The technical key points of thread rolling processing are summarized by the Huochun products, threads are pressed on a workpiece by using a thread forming hob, the thread forming hob needs large power, is slow in rotating speed and long in contact length, radial deformation and vibration of processing are effectively reduced, efficiency is high, but friction force of pressing threads is large, thermal deformation is large, and a large amount of lubricating oil is needed for maintaining processing. A double-cutter turning method is researched by wearing harbors and the like, two turning tools are used for simultaneously cutting two sides of a follow rest, the processing precision and efficiency are effectively improved, and the unit energy consumption is reduced. The machine tool adopts a clamping scheme that a pulling and clamping method replaces the traditional jacking method and a follow tool manipulator replaces a follow tool rest, and adopts a method of simultaneously turning two sides, so that the machining rigidity and the machining efficiency of the slender shaft are improved. The researches of Daihougang, Huang Xiao Dong and the like only improve the traditional machine tool machining method and the traditional machine tool, and do not solve the problem that the centrifugal force causes vibration to workpieces. Wanpeng and the like design a special machine tool for machining the variable-diameter slender shaft, and can effectively improve the machining precision and quality of the variable-diameter slender shaft. The machine tool still cannot get rid of the defects of single-tool machining and workpiece rotation. Liu shun Hua outlines the principle of whirling and the application in the thread cutting, whirling is the more advanced processing mode of modern times, and the principle of whirling the screw thread is through milling cutter blade disc eccentric slope unilateral high-speed rotation cutting work piece, and cooperation feed amount control makes the screw thread shaping. The cyclone milling has the disadvantage that the unilateral cutting of the milling cutter head can deform the workpiece in a one-way stressed mode. A three-cutter turning scheme with 120-degree difference in plane roundness is researched by a seaport and the like, the scheme is subjected to stress analysis, ANASYS software is adopted for simulation analysis, and the conclusion that the bending deformation of a turned workpiece in the scheme is far smaller than the machining deformation of a traditional lathe is obtained. The scheme is only studied theoretically and does not actually verify the authenticity of the theory. The majiang peak and the like design a double-cutter cyclone cutter head and a centering chuck which can be installed on a CA6140 lathe, the machining mode of rotary cutting of a cutter and feeding of a workpiece can be realized, the double-cutter machining reduces machining deformation in principle, and the machining precision is effectively improved. However, the double-cutter cyclone cutter head can only be used for processing slender shafts with single diameter, and the processing is not flexible enough.

In addition, some foreign scholars have also studied the above-mentioned problems. Wu Mingming and the like research the turning process of the slender shaft by adopting a finite element analysis method, and the research shows that the reverse turning method can improve the processing precision of the slender shaft. In order to reduce the trial and error times of selecting the best technological parameters for machining the slender shaft, the Milad Azvar and the like establish a parallel turning chatter stability multidimensional analysis model, and the method can quickly determine the cutting conditions without chatter and with high productivity, and improve the productivity and the machining precision of the slender shaft. Tie Link Wang et al analyzed the effects of different clamping modes on the machining deformation and natural frequency of the slender shaft by using Pro/ENGINEER and Pro/MECHANICA software, and analyzed and obtained a process scheme for reducing the machining deformation and vibration. Ding Pengfei and the like establish a reliability parameter optimization model by considering diameter errors aiming at the problem that diameter errors of any slender shaft can cause cutter abrasion and machining precision deterioration, and the model can well improve the reliability of selecting cutting parameters and improve the machining precision of the slender shaft. The Hong Wang et al mechanically analyzes the application of the reverse turning technology to slender shaft machining, establishes a mathematical model, and researches show that the bending deformation and the machining error under the reverse turning condition are far smaller than those of normal turning. The study of the students such as Wu Mingming, Milad Azvar, Tie Link Wang and the like is that from the perspective of cutting parameters, an error analysis is carried out by adopting a simulation method, the turning processing of a slender shaft is optimized, the improvement of the processing precision is limited, and the processing problem of a workpiece caused by centrifugal force cannot be solved. Lian Qing Chen and the like research an error compensation method based on a PID controller, which is used for compensating the machining error of the slender shaft. Guo Jianlianlianliang aims at the problem of diameter error caused by dynamic response during slender shaft machining, numerical simulation is carried out on the turning process by adopting Rayleigh beam theory, and the method for measuring the diameter error caused by vibration of a rotating workpiece is obtained. The research of Lian Qing Chen, Guo Jianlian and the like provides a solution in the aspect of actual error measurement, but the problem that centrifugal force influences machining is not solved substantially, and the improved machining precision is limited. Kai Bo Lu and the like research the dynamic process of turning the slender shaft by the double main shafts, analyze the dynamic response of a rotating workpiece, discuss the influence of cutting parameters on the shafting response and the natural frequency, and finally provide a method for improving the machining precision. But the method only stays in the theoretical analysis stage. Jin Chun Feng and the like research a processing method for turning trapezoidal threads on a slender shaft, explain a method and a way for processing trapezoidal threads on the slender shaft, and provide experience for high-precision processing of a slender screw rod. But still cannot get rid of the defects of the traditional processing. Yang Lin and the like research the machining process of the reducing slender shaft, and design a machine tool adopting a flexible hydraulic driven part and an elastic tailstock, thereby effectively improving the machining precision and the machining quality. But the defects of the rotating machining of the workpiece still exist.

In summary, the above researches partially solve the defects occurring in the machining of the slender shaft, but most of the researches do not relate to the cutting machining researches of multi-cutter symmetric circumferential and radial cutting and workpiece feeding.

Disclosure of Invention

In order to solve the technical problems, the invention provides a centrifugal force-free cutting device which converts the rotation of a workpiece into the rotation cutting of a symmetrical cutter, converts the axial feeding of the cutter into the tension feeding, ensures that the workpiece is hardly influenced by a centrifugal force, reduces the vibration when the workpiece is processed, avoids the stress on one side of the workpiece, reduces the deformation of the workpiece and can achieve the aims of improving the processing precision, the processing quality and the processing efficiency.

The technical scheme of the invention is realized as follows:

a centrifugal force-free cutting device is arranged on a frame and comprises a main shaft, a cutting mechanism positioned at the front end of the main shaft and a driving mechanism positioned at the rear end of the main shaft and used for driving the main shaft to rotate; the main shaft comprises an inner shaft and an outer shaft which are rotationally connected and respectively driven by an inner shaft motor and an outer shaft motor; the cutting structure is driven by an outer shaft to perform circumferential cutting, and the relative rotating speeds of the inner shaft and the outer shaft are synthesized to realize radial feeding of the cutter.

Furthermore, the cutting mechanism comprises a base frame arranged at the front end of the outer shaft, a sliding block which is connected with the base frame in a sliding mode and provided with arc teeth is arranged on the base frame, and a cutter is fixed on the sliding block; the front end of the inner shaft is provided with a wire coil; the arc teeth on the sliding block are meshed with the wire coil, and the feeding or retracting of the cutter is controlled by the synthesis through the rotating speed difference between the outer shaft and the inner shaft.

Furthermore, a first clamp and a second clamp for clamping the workpiece are respectively arranged at two axial ends of the cutting mechanism.

Furthermore, the second clamp is fixed at the front end of the inner shaft and synchronously rotates with the inner shaft, and the second clamp drives the wire coiling to rotate through static connection during rotation.

Furthermore, No. two anchor clamps include No. two bases and the activity clamping jaw tightly with base elasticity top, are equipped with the ball on the clamping jaw head and contact with the work piece.

Furthermore, the first clamp is arranged on the first base and is a three-jaw chuck with elastically telescopic clamping jaws, and the end parts of the clamping jaws are provided with rollers; or, alternatively, the first clamp is arranged on the first base and comprises a movable clamping jaw which is elastically pressed against the first base, and a ball is arranged on the head of the clamping jaw and is contacted with the workpiece.

Furthermore, the second base is a jaw clutch, and the front end of the inner shaft drives the wire to rotate through the static connection of the jaw clutch.

Furthermore, a workpiece feeding structure is further arranged on the rack, the workpiece feeding structure is a self-centering clamp, and the workpiece is clamped and pulled to move along the axial direction, so that the workpiece feeding is realized.

Further, the cutters are arranged in pairs, and the turning positions of each pair of cutters are symmetrical.

Further, the inner shaft and the outer shaft are connected through a sliding bearing, and the outer shaft is supported on the machine frame through a bearing.

The invention has the following beneficial effects:

1. the cutting mechanism can be detached and installed on the main shaft head, and the cutting mechanism can rotate along with the main shaft to cut a workpiece. The inner shaft and the outer shaft are driven to rotate through respective driving motors and speed reducing mechanisms, when the excircle of the shaft with the fixed diameter is cut, the wire coil and the base frame rotate at the same speed, the relative speed is zero, a cutter does not feed, and the equal-diameter cutting is realized; when cutting a stepped shaft, a conical surface and the like, the rotating speed of the disc wire is higher (or lower) than that of the base frame, and a certain rotating speed difference exists between the disc wire and the base frame, so that the diameter-variable cutting is realized. When the rotating speeds of the inner shaft and the outer shaft generate speed difference, a synthesis mechanism (a wire coil and a slide block with arc teeth) synthesizes the movement of the main shaft and the radial feed movement, and the synthesis mechanism is embodied as the feeding (or retracting) of a cutter.

2. Even number of symmetrical forces of the cutter are mutually offset in the cutting process, the stress stability of the workpiece is ensured in the machining process, and the deformation is avoided.

3. The fixture is fixedly arranged on the right of the cutting mechanism at a certain distance, the fixture is arranged on the left of the main shaft or the cutting mechanism, the clamping jaws of the fixture and the fixture are designed to be clamping jaws with balls or rollers, axial feeding of a workpiece can be radially clamped without being influenced, and the problem that the clamping jaws feed the workpiece due to the fact that the surfaces of the workpiece are uneven when the workpiece is axially fed is overcome.

4. The axial workpiece feeding mechanism adopts a pull clamp mode to feed the workpiece from left to right so as to ensure the rigidity of the shaft during machining.

Drawings

FIG. 1 is a diagrammatic view of the principles of motion of the present invention;

FIG. 2 is a diagrammatic illustration of the transmission principle of the present invention;

FIG. 3 is a schematic view of the spindle mechanism of the present invention;

FIG. 4 is a sectional view of the structure of example 1 of the present invention;

FIG. 5 is a sectional view of the structure of example 2 of the present invention;

FIG. 6 is a cross-sectional view of a second clamp of the present invention;

FIG. 7 is a perspective view of the second clamp of the present invention.

In the figure: 1-spindle, 101-inner shaft, 102-outer shaft, 2-cutting mechanism, 201-base frame, 202 slider, 203-cutter, 204 wire coil, 3-driving mechanism, 301-inner shaft motor, 302-outer shaft motor, 4-first clamp, 401-clamping jaw, 402-roller, 5-second clamp, 501-second base, 502-movable clamping jaw, 503-ball, 504-spring, 5' -first clamp, 501 ' -first base, 502 ' -movable clamping jaw, 503 ' -ball, 504 ' -spring, 6-self-centering clamp and 7-workpiece.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1-4, a centrifugal force-free cutting device is arranged on a frame, and mainly comprises a main shaft 1, a cutting mechanism 2 located at the front end of the main shaft, and a driving mechanism 3 located at the rear end of the main shaft 1 and used for driving the main shaft 1 to rotate; the main shaft 1 comprises an inner shaft 101 and an outer shaft 102, the outer shaft 102 is sleeved outside the inner shaft 101, the inner shaft and the outer shaft can rotate mutually, and the inner shaft 101 and the outer shaft 102 are connected by a solid lubrication sliding bearing or a bearing bush because of low relative rotating speed of the inner shaft and the outer shaft. Because the type of a processed workpiece is a slender shaft, the feed amount and the back tool cutting amount are small, and the cutting force is also small, the speed type combination is selected for the bearing combination, a pair of deep groove ball bearings and a thrust ball bearing combination are selected for the front support of the outer shaft 102, the rigidity of the front support is improved by the double deep groove ball bearings, and the influence of the thermal deformation of the main shaft can be reduced by the front support configuration of the thrust ball bearing; a pair of angular contact ball bearings is selected for combination of the rear support, and the anti-overturning capacity of the main shaft is improved by adopting a reverse installation mode.

Inner shaft 101 and outer shaft 102 are driven by inner shaft motor 301 and outer shaft motor 302, respectively; the inner shaft 101 needs to be matched with an electric control system to carry out stepless speed regulation, so that the servo motor is selected as a power source, the rotating speed of the inner shaft 101 can be accurately regulated and controlled, and the cutting feed amount is realized through the speed difference of the inner shaft and the outer shaft. The transmission schemes of the inner spindle and the outer spindle are both selected from common cylindrical straight gears for transmission, and the transmission schemes are simple and reliable and can ensure the rotation precision. As shown in fig. 3 and 4, the outer shaft gear is placed near the front support to reduce the deformation of the outer shaft; due to structural limitation, the gear of the inner shaft 101 can only be placed at the tail end, and in order to enhance the rigidity of the tail end of the inner shaft 101, deep groove ball bearings are added on the left and right of the gear to serve as supports for the tail end of the inner shaft 101. As shown in fig. 3, the driving mechanism is disposed on the left and right sides of the main shaft 1 to avoid the main shaft 1 from bending and deforming to one side by a single force.

The cutting mechanism 2 is fixed at the front end of the outer shaft 102 and comprises a base frame 201, a sliding block 202 which is connected with the base frame 201 in a sliding mode and is provided with arc teeth is arranged on the base frame 201, a cutter 203 is fixed on the sliding block 202, and the cutter 203 is driven by the outer shaft 102 to cut the circumference; a wire coiling 204 is arranged at the front end of the inner shaft 101; the arc teeth on the sliding block 202 are meshed with the wire rod 204, the feeding or retracting of the cutter 203 is controlled synthetically through the rotation speed difference between the outer shaft 102 and the inner shaft 101, the wire rod is used, the machining process of the wire rod is mature, the feeding amount is accurately determined through the thread pitch, the feeding movement speed driven by the wire rod is constant, uniform cutting can be achieved, and the wire rod can bear larger radial cutting counterforce.

The excircle of the bearing bush of the solid lubrication sliding bearing is in interference fit with the inner hole of the outer shaft 102, the excircle of the inner shaft 101 is in transition fit with the inner circle of the bearing bush with the solid lubricant, the inner shaft 101 and the outer shaft 102 can rotate relatively, and the wire coiling 204 and the base frame 201 are respectively driven to rotate at different speeds by the power transmission of the gear of the inner shaft 101 and the gear of the outer shaft 102. The inner shaft gear is arranged at the tail of the inner shaft 101, the inner shaft 101 is driven to rotate through a key, and deep groove ball bearings are arranged in front of and behind the gear to increase the rigidity of the shaft near the tail gear. A space is reserved at the tail of the inner shaft 101 for placing an oil carrying disc to convey lubricating oil to a lubricating system. The outer shaft 102 support is supported in a supporting mode that one end is fixed and the other end is free, the front support is fixed by using a sleeve cup, and the rear support is freely arranged on the box body. Because the rotating speed requirement for processing the slender shaft is high, the front support adopts a pair of deep groove ball bearings, and the front ends of the thrust ball bearings are configured to ensure high axial precision and rigidity of the main shaft. The rear support is reversely arranged by a pair of angular contact ball bearings so as to improve the overturn resistance of the main shaft. The outer shaft gear drives the outer shaft 102 to rotate through a key, the gear is axially fixed by using a locking nut for radial locking and looseness prevention, and the gear is arranged close to the front support so as to improve the rigidity of the main shaft.

In order to enable the wire coiling 204 and the base frame 201 to rotate simultaneously, the invention skillfully adopts a shaft sleeve shaft structure, the inner shaft 101 realizes the wire coiling rotation, the outer shaft 102 realizes the circular cutting motion, the right end of the inner shaft 101 drives the wire coiling 204 to rotate through the static connection of a jaw clutch, the outer shaft 102 drives the base frame 201 to rotate through the bolt fastening, if the rotating speed of the inner shaft 101 is higher (or lower) than that of the outer shaft 102, the wire coiling 204 and the base frame 201 can generate a relative rotating speed, so that the cutter can be fed (or withdrawn). When the excircle of the shaft with the fixed diameter is cut, the wire rod 204 and the base frame 202 rotate at the same speed, the relative speed is zero, the cutter 203 does not feed, and the equal-diameter cutting is realized; when cutting a stepped shaft, a conical surface and the like, the rotating speed of the wire coiling 204 is higher (or lower) than that of the base frame 202, and a certain rotating speed difference exists between the stepped shaft and the conical surface, which is embodied as cutter feeding (or cutter withdrawing), so that diameter-variable cutting is realized.

The arc teeth on the sliding block 202 are in engaged transmission with the disc thread, theoretically, the arc tooth profile needs to be consistent with the plane thread, the contact surface is large, and the transmission effect is best. When the circular arc tooth profile is designed, because the spiral thread is an Archimedes spiral, the upper circular arc and the lower circular arc of the circular arc tooth need to be fitted with a section of Archimedes spiral, an offset circular arc is calculated, the circular arc radius of the outer side of the convex tooth of the circular arc tooth is smaller than the minimum radius of the plane thread, and the circular arc radius of the inner side of the convex tooth is larger than the maximum radius of the plane thread, so that the circular arc tooth can slide at each position of the plane thread.

The machine frame is provided with a track, the workpiece feeding mechanism is connected with the track in a sliding mode, the workpiece feeding mechanism is a self-centering clamp 6, the workpiece 7 is clamped and then driven by the driving mechanism, the workpiece 7 is pulled to move rightwards, so that the workpiece feeding is realized, and the rigidity of the shaft during machining can be ensured in a pulling and clamping mode. How the self-centering clamp 6 realizes self-centering is another complete technical scheme, and the invention is not described in detail.

The cutters 203 are arranged in pairs, the turning positions of each pair of cutters 203 are symmetrical, the cutting stability brought by symmetrical force is fully utilized, the cutters 203 can perform circumferential symmetrical rotary cutting and radial feed cutting simultaneously, and the workpiece 7 only performs axial feed movement.

As shown in fig. 2 and 4, a first clamp 4 is arranged on a frame at a certain distance from the right side of the cutting mechanism 2, and a second clamp 5 is arranged at the tail end of the main shaft. The second clamp 5 is arranged between the inner shaft 101 and the cutting mechanism 2 and fixedly connected with the inner shaft 101; the movable clamping jaw 502 of the second clamp 5 is arranged in the second base 501, the movable clamping jaw 502 is ejected out through a spring, and the four movable clamping jaws 502 are abutted together. The clamping jaw head is provided with a ball 503 which is contacted with a workpiece, and the working principle of the mechanism is as follows: the initial state spring 504 has pre-compression amount to enable the four clamping jaws to be tightly close together, when the workpiece 7 is fed, the workpiece 7 pushes the movable clamping jaw 502 open, the movable clamping jaw 502 clamps the workpiece 7, when the workpiece 7 is machined, the spindle 1 rotates, the second clamp 5 also rotates, the ball 503 on the movable clamping jaw 502 enables the movable clamping jaw 502 and the workpiece 7 to perform relative movement of rotation and translation, and when the diameter of the workpiece 7 changes, the spring on the movable clamping jaw 502 can adapt to the diameter of the workpiece, so that the movable clamping jaw 502 can freely change to clamp the workpiece.

Example 2

As shown in fig. 5, in embodiment 1, the position of the first clamp 5' is not changed, and the second clamp 5 is fixed to the front end of the inner shaft. The first clamp 5 'and the second clamp 5 adopt the same flexible clamping structure, the second clamp 5 comprises a second base 501, a movable clamping jaw 502, a ball 503 and a spring 504, and the first clamp 5' comprises a first base 501 ', a movable clamping jaw 502', a ball 503 'and a spring 504'. The second base 501 is a jaw clutch, the second fixture 5 and the inner shaft 101 rotate synchronously, and the inner shaft 101 drives the wire coil 204 to rotate through the static connection of the jaw clutch.

Four movable clamping jaws 502 and 502 ' of the second clamp 5 and the first clamp 5' are uniformly distributed on the circumferences of the second bases 501 and 501 ', freely move in the through grooves of the second bases 501 and 501 ', and the movable clamping jaws 502 and 502 ' are provided with ear plates to prevent the movable clamping jaws from falling off from the through grooves. The top cover is embedded on the excircle of the second base 501 and the second base 501' through screws, and the guide pillar is installed on the top cover through screws. The movable jaws 502, 502 ' have blind holes facing the guide posts, and the springs 504, 504 ' are mounted in the blind holes and penetrate through the guide posts, and can freely extend and retract along with the movement of the movable jaws 502, 502 '. Each movable jaw 502, 502 'is provided with two balls 503, 503' for reducing friction between the movable jaw 502, 502 'and the workpiece, the balls 503, 503' are mounted on the jaw head, axial displacement thereof is limited by the blocking cover, and radial displacement of the balls is limited by the regular hexagon grooves of the movable jaws 502, 502 'on which the balls 503, 503' are mounted. The movable jaws 502, 502' are provided with ramps for resolving the force of the workpiece and the jaws so that the workpiece can be ejected from the jaws. The front and back surfaces of the second base 501 are provided with rectangular teeth of a jaw clutch and are arranged between the inner shaft 101 and the wire coil 204, and the front and back surfaces are respectively meshed with the rectangular teeth of the wire coil 204 and the inner shaft 101 to transmit power. Four counter bores on base number two 501 are used for axial location of mounting on inner shaft 101.

Example 3

As shown in fig. 4, in the centrifugal force-free cutting device provided in this embodiment 3, on the basis of embodiment 1, the second clamp 5 adopts a structure of an elastic clamping jaw and a ball 503, the first clamp 4 adopts an elastic three-jaw chuck structure, a roller (the roller and the ball act in the same direction) is arranged on a jaw head of a movable jaw of the three-jaw chuck, and the first clamp 4 and the second clamp 5 are concentric. The second clamp 5 is arranged on the right side of the cutting mechanism 2 in a matched mode and provided with the roller 402 and the first clamp 4 with the spring clamping jaws to clamp the workpiece together, and machining rigidity of the workpiece can be well enhanced. The elastic structure of the clamping jaw can be realized in various ways, for example, on the existing clamping jaw chuck, the clamping jaw is designed in a split mode, one split body is meshed with the wire coil to fix the approximate position, the other split body is connected with the split body through the elastic structure, and the diameter change range of a workpiece is within the deformation range of the elastic structure, so that the structure is not described in detail in the invention.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The utility model provides a centrifugal force free cutting device, sets up in the frame, its characterized in that: the cutting machine comprises a main shaft, a cutting mechanism positioned at the front end of the main shaft and a driving mechanism positioned at the rear end of the main shaft and used for driving the main shaft to rotate;

the main shaft comprises an inner shaft and an outer shaft which are rotationally connected and respectively driven by an inner shaft motor and an outer shaft motor;

the cutting structure is driven by an outer shaft to carry out circumferential cutting, and the relative rotation speed difference of the inner shaft and the outer shaft is synthesized to realize radial feeding of the cutter.

2. The centrifugal-force-free cutting apparatus according to claim 1, wherein: the cutting mechanism comprises a base frame arranged at the front end of an outer shaft, a sliding block which is connected with the base frame in a sliding mode and provided with arc teeth is arranged on the base frame, and a cutter is fixed on the sliding block; the front end of the inner shaft is provided with a wire coil; the arc teeth on the sliding block are meshed with the wire coil, and the feeding or retracting of the cutter is controlled by the synthesis through the rotating speed difference between the outer shaft and the inner shaft.

3. The centrifugal-force-free cutting apparatus according to claim 2, wherein: and a first clamp and a second clamp for clamping a workpiece are respectively arranged at two axial ends of the cutting mechanism.

4. The centrifugal-force-free cutting apparatus according to claim 3, wherein: and the second fixture is fixed at the front end of the inner shaft and synchronously rotates with the inner shaft, and the second fixture drives the wire coiling to rotate through static connection during rotation.

5. The centrifugal-force-free cutting apparatus according to claim 4, wherein: the second clamp comprises a second base and a movable clamping jaw elastically and tightly propped against the second base, and a ball is arranged on the clamping jaw head and is in contact with a workpiece.

6. The centrifugal-force-free cutting apparatus according to claim 5, wherein: the first clamp is arranged on the first base and is a three-jaw chuck with clamping jaws capable of elastically stretching, and the end parts of the clamping jaws are provided with rollers; or the first clamp is arranged on the first base and comprises a movable clamping jaw elastically and tightly propped against the first base, and a ball is arranged on the clamping jaw head and is contacted with the workpiece.

7. The centrifugal-force-free cutting apparatus according to claim 5, wherein: the second base is a jaw clutch, and the front end of the inner shaft drives the wire coil to rotate through static connection of the jaw clutch.

8. The centrifugal-force-free cutting apparatus according to claim 1, wherein: the machine frame is also provided with a workpiece feeding mechanism, the workpiece feeding mechanism is a self-centering clamp, and the workpiece is clamped and pulled to move along the axial direction, so that the workpiece feeding is realized.

9. The centrifugal-force-free cutting apparatus according to claim 2, wherein: the cutters are arranged in pairs, and the turning positions of each pair of cutters are symmetrical.

10. The centrifugal-force-free cutting apparatus according to claim 1, wherein: the inner shaft and the outer shaft are connected through a sliding bearing, and the outer shaft is supported on the frame through a bearing.