Large-aperture numerical control deep hole reducing boring cutter and special-shaped deep hole machining method

Abstract

The invention discloses a large-aperture numerical control deep hole variable-diameter boring cutter and a special-shaped deep hole machining method. The large-aperture numerical control deep hole variable-diameter boring cutter comprises a boring cutter assembly located at the front end of a cutter bar. The servo motor is in communication connection with the numerical control system; the transmission assembly is used for connecting the power output end of the servo motor with the boring cutter assembly in a transmission manner so as to control the boring cutter assembly to move radially; the telescopic supporting assemblies are arranged in the circumferential direction of the cutter bar and used for being matched with the hole wall; the hydraulic unit is matched with the telescopic supporting assembly; an endoscope probe is arranged at the position, matched with the boring cutter assembly, of the cutter bar. According to the large-aperture numerical control deep hole reducing boring cutter and the special-shaped deep hole machining method, the endoscope hole is additionally formed in the cutter bar of the boring cutter, so that the machining condition is observed in real time through the endoscope probe arranged in the endoscope hole.

Description

Technical Field

[0001] The present invention relates to the field of special-shaped deep hole processing, and more specifically, to a large-diameter CNC deep hole variable-diameter boring tool and special-shaped deep hole processing. Background Art

[0002] In the machinery manufacturing industry, it is generally stipulated that when the ratio of hole depth L to hole diameter D is greater than 10 times, that is, L>10D, the hole is called a deep hole. Deep hole processing is carried out in a closed or semi-closed state, and the cutting condition of the tool cannot be directly observed. The cutting condition of the tool can only be judged by listening to the sound, constantly observing the shape and color of the iron chips, and touching the tool rod by hand. At the same time, due to the limitation of the aperture size, the tool diameter is small, the overhang length is long, the rigidity is poor, and it is easy to vibrate. It is easy to make the tool accuracy difficult to control during the processing, and the cutting conditions are relatively poor, making it difficult to obtain a low surface roughness. At the same time, the chips are not easy to discharge, which is easy to block and affect the processing efficiency. The cutting heat is not easy to dissipate, which is easy to increase the temperature of the tool and the workpiece, affecting the processing accuracy and tool life.

[0003] Therefore, deep hole processing has always been regarded as a recognized technical problem in the field of metal cutting. Although in the prior art, this technical problem is solved by setting a matching telescopic support mechanism on the tool rod, such as the prior art with patent application number 202110971698.1 and patent name of modular boring tool, the modular boring tool adopts vulcanized body, expansion body, support member and roller to flexibly support the boring tool in the drilling operation, so that the relative rotation between the boring tool and the hole wall can be more stable and smooth, but because its vulcanized body is elastic, it can be elastically deformed. In actual application, the operator adjusts the deformation direction and degree of the vulcanized body to adjust the support performance of each support member. When the vulcanized body is compressed by the increased axial pressure, the vulcanized body diffuses radially outward, thereby providing stronger support force to the inner side wall of the accommodating cavity. When the axial pressure on the vulcanized body is weakened and stretched, the first vulcanized body contracts radially inward, thereby weakening its support force on the inner side wall of the first accommodating cavity. However, the problem is that the support obtained by this structure is fixed support. Although the support pressure can be adjusted to achieve flexible support, for the same support module, it cannot change with the change of the aperture, that is, variable diameter support cannot be achieved. Summary of the invention

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0005] In order to achieve these purposes and other advantages of the present invention, a large-aperture CNC deep-hole variable-diameter boring tool is provided, characterized in that it includes:

[0006] A boring tool assembly located at the front end of the tool bar;

[0007] A servo motor connected to the numerical control system for communication;

[0008] A transmission assembly is used to connect the power output end of the servo motor to the boring tool assembly to control the radial movement of the boring tool assembly;

[0009] A plurality of telescopic support components arranged on the circumference of the cutter bar and used to cooperate with the hole wall;

[0010] a hydraulic unit cooperating with the telescopic support assembly;

[0011] Wherein, the tool rod is provided with an endoscope probe at a position matching with the boring tool assembly.

[0012] Preferably, the telescopic support assembly is configured to include:

[0013] A T-shaped support seat is embedded in the inside of the cutter bar, and an oil groove I is arranged in the extension end thereof;

[0014] A support head is sleeved on the T-shaped support seat, and a guide column is arranged at the center thereof and can extend into the oil groove I;

[0015] A housing that is connected to a T-shaped support seat through a fixing mechanism to limit the support head;

[0016] There is a predetermined gap between the outer wall of the support head and the inner wall of the shell to obtain the oil groove II, and the support head is provided with a step end surface in an outwardly convex manner at one end close to the support seat, which is in a clearance fit with the gap of the inner wall of the shell;

[0017] The oil grooves I and II are connected to an external hydraulic unit via a hydraulic control oil circuit arranged inside the cutter bar.

[0018] Preferably, a bull's eye ball is provided at the top center of the support head.

[0019] Preferably, a plurality of wrench holes are provided on the top of the support head.

[0020] Preferably, the housing is provided with a thread matching with the module groove on the tool rod.

[0021] Preferably, the transmission assembly is configured to include:

[0022] A thrust rod is arranged at the axis of the tool bar and is transmission-connected to the boring tool assembly through the transmission module I;

[0023] A ball screw fixedly connected to the thrust rod, on which a screw nut connected by a thread is arranged;

[0024] Transmission module II for connecting the lead screw nut to the power output end of the servo motor;

[0025] Wherein, matching bearings are arranged at both ends of the screw nut.

[0026] Preferably, the transmission module I is configured to include:

[0027] Rack I fixedly connected to the thrust rod;

[0028] A helical gear I and a helical gear II are arranged side by side on the rack I through a rotating shaft and a bearing seat, and the helical gear I is in meshing state with the rack I;

[0029] Rack II fixedly connected to the boring cutter assembly;

[0030] A helical gear III that spatially connects the rack II with the helical gear II for transmission;

[0031] Wherein, the knife bar is provided with a rack seat matched with the corresponding rack, and the rack seat is provided with a needle bearing I matched with the bottom surface of each rack;

[0032] The tool rod is provided with a guide rail seat at the position where it contacts the boring tool assembly in radial movement, and a needle bearing II is provided at the position where the guide rail seat matches the side wall of the boring tool assembly.

[0033] A method for processing special-shaped deep holes, which uses a large-diameter CNC deep hole variable-diameter boring tool, comprising:

[0034] S1. Based on the overall transmission ratio of the boring tool, the CNC system drives the screw nut to rotate through the transmission module II through the forward or reverse rotation of the servo motor, thereby driving the thrust rod on the ball screw to move axially;

[0035] S2. When the thrust rod moves axially, the boring cutter is driven to move radially through the transmission module I, so that the radial position of the boring cutter is changed, and the boring hole diameter is adjusted to pre-drill the bottom hole;

[0036] S3. After the pre-drilling of the bottom hole is completed, the boring tool is inserted into the hole to the position of the first step, and the switch of the hydraulic unit is turned on, so that the telescopic support assembly extends outward under the action of the hydraulic pressure and contacts the hole wall of the bottom hole, and the processing operation of the front end hole is started;

[0037] S4, replace the boring tool clamp on the boring tool assembly with a reverse boring tool clamp, process the reverse step, and complete the processing of the special-shaped hole;

[0038] During the machining process, the endoscope probe installed on the boring tool assembly is used to observe the machining status in real time.

[0039] Preferably, the process of extending the support head in the telescopic support assembly is:

[0040] The hydraulic station of the hydraulic unit controls the hydraulic oil to enter the oil tank I. By increasing the amount of oil in the oil tank I, the guide column is provided with power, so that the support head integrally provided with the guide column extends outward. When the support head is extending, the hydraulic oil in the oil tank II flows back to the hydraulic station, leaving space for the support head to extend outward.

[0041] The process of retracting the support head in the telescopic support assembly is as follows:

[0042] The hydraulic station of the hydraulic unit enters oil tank II. Through the increase of oil volume in oil tank II, the hydraulic oil exerts force on the end face of the step, pressing the support head back to the initial position. When the support head is retracting, the hydraulic oil in oil tank I will flow back to the hydraulic station, leaving space for the support head to retract.

[0043] Preferably, the working process of the transmission module I is:

[0044] When the thrust rod moves axially, it drives the rack I fixedly connected to the thrust rod to move axially synchronously;

[0045] Helical gears I and II convert the axial motion of rack I into that of helical gear III, thereby causing rack II meshing with helical gear III to move radially.

[0046] When the rack II moves axially, it drives the boring tool assembly fixedly connected to the rack II to move radially synchronously, thereby realizing the boring tool diameter changing operation during the drilling process.

[0047] The present invention has at least the following beneficial effects:

[0048] Firstly, the present invention adds an endoscope hole in the existing boring bar, so that the processing status can be observed in real time through the endoscope, and the cutting status of the tool can be obtained.

[0049] Secondly, because the present invention cooperates with the numerical control processing method, the diameter can be changed in real time during the processing, and complex deep holes can be processed, such as a bottle-shaped cavity with small ends and a large middle.

[0050] Thirdly, the present invention sets the tool holder to be modular, and different workstation processing can be achieved by simply replacing different tool holders according to the process, which greatly reduces the time for tool changing and auxiliary operations, saves tool costs, and improves processing accuracy and production efficiency.

[0051] Fourthly, in order to solve the problems of small tool diameter, long overhang length, poor rigidity, easy vibration, and easy tool deviation during processing, the present invention arranges multiple telescopic support assemblies on the tool rod to effectively provide support for the tool and ensure its processing stability and concentricity.

[0052] Fifthly, the present invention is designed with a telescopic support assembly. After the telescopic support assembly is extended, there is a gap between the knife rod and the hole wall, and iron filings can be effectively discharged from this space.

[0053] Sixthly, the present invention designs a telescopic support assembly for use on a variable diameter boring tool, which uses a hydraulic method to control its telescopic state. Compared with the existing technology, its support range can be achieved by adjusting the compressed oil. The support effect is stable and can support workpieces of different heights.

[0054] Specifically, the support extension amount of the present invention changes with the change of the hole diameter of the workpiece. If the hole diameter increases, the support extends, and the hydraulic oil that needs to enter will increase accordingly, and finally reach the set pressure value, and the stability of the support can be guaranteed only when the pressure value remains unchanged. In specific applications, the pressure value can be adjusted to a pressure value that is more suitable for the current workpiece according to actual conditions such as the hardness and wall thickness of the workpiece. Generally speaking, the greater the pressure value, the greater the support force, and the greater the cutting force that can be tolerated. The support force can be increased or decreased according to the actual application needs to achieve a better support effect.

[0055] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a structural schematic diagram of a large-aperture CNC deep-hole variable-diameter boring tool of the present invention;

[0057] Figure 2 It is a structural schematic diagram of the shank section of the large-aperture CNC deep-hole variable-diameter boring cutter of the present invention;

[0058] Figure 3 This is a schematic diagram of a partially enlarged structure of the interior of the shank section of the large-aperture CNC deep-hole variable-diameter boring cutter of the present invention;

[0059] Figure 4 It is a partial structural schematic diagram of the large-aperture CNC deep-hole variable-diameter boring tool of the present invention, where the boring tool assembly is located on the tool bar section;

[0060] Figure 5 It is a schematic diagram of the top view of the transmission module I of the present invention;

[0061] Figure 6 It is a schematic diagram of the top view of the structure of the rack seat and the rack in the transmission module I of the present invention;

[0062] Figure 7 It is a side view structural diagram of the cooperation between the rack seat and the rack in the transmission module I of the present invention;

[0063] Figure 8 It is a bottom view connection diagram of the transmission module I of the present invention;

[0064] Fig. 9It is a schematic diagram of the transmission inside the large-aperture CNC deep-hole variable-diameter boring cutter of the present invention;

[0065] Fig.10 A working schematic diagram of the large-aperture CNC deep-hole variable-diameter boring tool of the present invention;

[0066] Fig.11 It is a schematic structural diagram of adding a connecting handle between the tool rod and the tool handle in the large-diameter CNC deep-hole variable-diameter boring tool of the present invention;

[0067] Fig.12 This is a schematic diagram of the structure of the inner hole in the shape of a treasure bottle in the embodiment;

[0068] Fig.13 This is a schematic diagram of the bottom hole after pre-drilling in the embodiment;

[0069] Fig.14 This is a schematic diagram of the front end hole after processing in the embodiment;

[0070] Fig.15 This is a schematic diagram of processing the reverse side step in the embodiment;

[0071] Fig.16 It is a schematic cross-sectional structure diagram of a telescopic support assembly in one embodiment of the present invention;

[0072] Fig.17 This is a schematic diagram of the side structure of a telescopic support assembly in one embodiment of the present invention;

[0073] Fig.18 This is a schematic diagram of a top view of a telescopic support assembly in one embodiment of the present invention;

[0074] Fig.19 It is a schematic cross-sectional structure diagram of a telescopic support assembly in an extended state in one embodiment of the present invention;

[0075] Fig. 20 It is a schematic diagram of the side structure of the telescopic support assembly in an extended state in one embodiment of the present invention;

[0076] Fig.21 It is a schematic diagram of the exploded structure of the telescopic support assembly;

[0077] Fig. 22 This is a schematic diagram of a state in which the telescopic support assembly switches to an extended state under the action of hydraulic oil in one embodiment of the present invention;

[0078] Fig.23 A state diagram of a set of telescopic support components on the tool bar being fully extended;

[0079] Fig.24This is a schematic diagram of a state in which the telescopic support assembly switches to a retracted state under the action of hydraulic oil in one embodiment of the present invention;

[0080] Fig.25 This is a diagram of the state of a set of telescopic support components on the tool rod after being retracted. DETAILED DESCRIPTION

[0081] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0082] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0083] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the term is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "Ⅰ" and "Ⅱ" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0084] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or an indirect connection through an intermediate medium. It can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] like Figure 1 As shown, for processing large-diameter and shallow holes, the entire tool mainly includes a CNC system U-axis drive servo motor 1, a transmission module II 3, a transmission module I 2, a transmission assembly 4, a boring tool assembly 5, a hydraulic unit 6, a telescopic support assembly 7, a tool rod 8, an endoscope 9, etc.

[0086] The servo motor 1 is connected to the numerical control system, and the numerical control system controls the rotation of the servo motor 1 to drive the transmission module II 2 to rotate the screw nut 42. The screw nut 42 cannot move axially, and the rotation of the screw nut 42 drives the ball screw 40 to move axially; the ball screw 40 is rigidly connected to the thrust rod 41, and the thrust rod is rigidly connected to the rack. The rack and the gear are precisely meshed, driving the boring tool clamp 50 on the boring tool assembly 5 to move radially. The hydraulic oil pipe 7 is connected to the hydraulic station, and the telescopic support assembly 7 is controlled by the hydraulic system to switch the support tool rod 8. The endoscopic probe 10 can observe the processing situation in real time, and the accessories in the entire tool, such as the boring tool assembly 5, are modularly set, which is convenient for replacement and assembly.

[0087] Furthermore, when processing large-diameter deep inner holes similar to the shape of a vase, the tool needs to be processed along the contour. The diameter increases from the minimum 157mm to 204mm. The diameter of the workpiece changes greatly, and ordinary tools cannot meet the processing requirements. CNC variable-diameter tools are required. The inner hole depth of the workpiece is 2400mm, which is equivalent to 15 times the diameter. Ordinary tools are not rigid enough and are prone to vibration during processing, so tool support is required.

[0088] Its working principle is roughly as follows: Fig.10 As shown in the figure, when the hydraulic unit is started, the hydraulic pump sucks hydraulic oil from the oil tank and outputs it under pressure. The pressure oil flows to the oil tank I 71 through the oil pipe 60, pushing the support head 72 to extend, thereby supporting the tool bar 8. When the support needs to be retracted, the flow direction of the hydraulic oil is changed by controlling the reversing valve, and the pressure oil flows to the oil tank II 74 through the hydraulic control oil pipe 61 inside the tool bar to retract the support head 72 of the hydraulic cylinder. At the same time, the pressure and flow of the system need to be adjusted according to the different surface hardness of the workpiece to meet different support requirements and avoid crushing the inner hole surface of the workpiece.

[0089] like Figure 2 , Fig.10 As shown, the present invention is provided with a matching telescopic support assembly on the conventional tool, and two sets of hydraulic control oil circuits 80 are provided on the tool bar 8 to control the internal support head 70 of the telescopic support assembly 7 to be freely retractable, and the bull's eye ball 76 on the top of the support head 72 is pressed against the hole wall with a fixed pressure to resist the vibration of the tool during cutting. Specifically, Figure 16-Figure 25 As shown, the structure of the telescopic support assembly is configured to include:

[0090] A T-shaped support seat 70 is embedded in the knife bar 8, and an oil groove I 71 is provided in its extended end;

[0091] A support head 72 is sleeved on a T-shaped support seat, and a guide column 701 is provided at the center thereof, which can extend into the oil groove I 71;

[0092] The housing 73 is connected to the T-shaped support seat 70 through a fixing mechanism (i.e., screws 78) to limit the support head 72. When the support head 72 is extended, the hydraulic oil needs to be controlled from the hydraulic station to enter the oil tank I 71, thereby providing power for the guide column 701, and the guide column 701 controls the support head 72 to extend to the position where support is required; at the same time, when the support head 72 is extended, the hydraulic oil in the guide column 701 will flow back to the hydraulic station, leaving space for the support head 72 to extend;

[0093] There is a predetermined gap between the outer wall of the support head 72 and the inner wall of the shell 73 to obtain the oil groove II 74, and the support head 72 is provided with a step end surface 75 in a convex manner at one end close to the support seat 70, which is in a clearance fit with the inner wall gap of the shell 73. In actual application, various O-rings 79 are provided between the structures to ensure the sealing performance;

[0094] The oil groove I 71 and the oil groove II 74 are connected to the external hydraulic unit 6 through the hydraulic control oil circuit 80 arranged inside the tool rod 8. When the support head needs to be retracted, the hydraulic oil needs to be controlled from the hydraulic station to enter the oil groove II 74. At this time, the hydraulic oil will act on the step end surface 75 on the circumference of the support head 72, thereby controlling the retraction of the support head 72. At the same time, when the support head 72 is retracted, the hydraulic oil in the oil groove II 74 will flow back to the hydraulic station, leaving space for the retraction of the support head 72.

[0095] The top of the support head 72 is provided with a plurality of wrench holes 77 for facilitating cooperation with an external wrench to screw the telescopic support assembly into a predetermined installation slot.

[0096] The housing 73 is provided with a thread (not shown) that matches the module slot on the tool bar 8. When the tool needs a support mechanism during processing, it is only necessary to select a telescopic support module of the corresponding size, and then reserve the corresponding module screw-in slot on the tool according to the interface of the module. At the same time, based on the advantage of the modularization of the support mechanism, different numbers of modules can be freely selected according to processing requirements. Multiple support holes at the same diameter can be extended and retracted at the same time, which can play a good supporting role for the various diameters of the inner hole of the workpiece, making the tool processing process more stable.

[0097] The function of the telescopic support assembly in this scheme: the support head 72 in the telescopic support assembly 7 is fitted and pressed against the hole wall with a fixed pressure under the action of hydraulic pressure to resist the vibration generated by the tool cutting. The hydraulic unit 6 is used to ensure that there is always a constant support pressure between the hole wall and can float freely with the change of the inner hole shape. The hydraulic support is stable and has a large support force, which can effectively ensure the processing accuracy and can float freely with the change of the inner hole shape. The tool rod 8 is equipped with 2 sets of hydraulic support seats, and the extension and contraction of the support seats are controlled by the hydraulic support system.

[0098] Further, the transmission assembly is configured to include:

[0099] A thrust rod 41 disposed at the axis of the tool bar 8 and connected to the boring tool assembly 5 through the transmission module I3;

[0100] A ball screw 40 fixedly connected to the thrust rod 41, on which a screw nut 42 connected by a thread is provided;

[0101] The transmission module II2 connects the lead screw nut 42 to the power output end of the servo motor 1, and the U-axis of the machine tool numerical control system drives the servo motor 1 to perform forward and reverse movements. During operation, the lead screw nut 42 is driven to rotate by the servo motor 1 and the transmission module II2, and the transmission module II2 includes: a synchronous pulley I21 matched with the power output shaft end of the servo motor 1, a synchronous belt 20, and a synchronous pulley II22 connected to the lead screw nut 42, that is, the servo motor 1 rotates forward and the synchronous belt 20 moves downward, driving the synchronous pulley 21 to rotate, and then the lead screw nut 42 connected to the synchronous pulley 21 rotates synchronously. In this solution, the transmission module II2 makes full use of the synchronous belt 20 transmission with an accurate transmission ratio, and there will be no slippage, which is used to ensure transmission accuracy, and can also adapt to a certain degree of harsh environment;

[0102] Wherein, the two ends of the screw nut 42 are provided with matching bearings 44. In this scheme, the two ends of the screw nut 42 are fixed with bearings 44, so that the screw nut 42 only rotates without axial movement. The rotation of the screw nut 42 drives the ball screw 40 to move axially; the transmission of the screw nut 42 can achieve precise linear motion and accurately control the displacement. The ball screw 40 is rigidly connected to the thrust rod 41 by a connecting sleeve 45. The movement law is: the motor drives the synchronous belt to move downward, and the synchronous belt drives the thrust rod to move to the right through the screw nut 42, and vice versa to the left. The transmission ratio of the two synchronous pulleys is 1:2, that is, the motor rotates 2 circles, and the ball screw 40 moves axially by 1 pitch. One pitch of the ball screw 40 is 5mm, that is, the thrust rod moves 2.5mm when the motor rotates one circle.

[0103] Furthermore, if Figure 3-Figure 9 , the transmission module I2 is configured to include:

[0104] A rack I20 fixedly connected to the thrust rod 41, wherein the thrust rod 41 and the rack I20 are connected by a screw 29;

[0105] The helical gear I 23 and the helical gear II 24 are arranged side by side on the rack I 20 through the rotating shaft 21 and the bearing seat 22, and the helical gear I 23 is in meshing with the rack I 20;

[0106] A rack II 25 fixedly connected to the boring tool assembly;

[0107] The helical gear III26 connects the rack II25 and the helical gear II24 in space. In this scheme, the rack I20 transmits power to the single helical gear III26 through two parallel helical gears I23 and II24, and the single helical gear III26 transmits power to the rack II25. This scheme uses the fact that the teeth of the helical gears gradually enter and exit the meshing, so the overlap of the helical gears is greater than that of the spur gears, the transmission is smoother, the impact and noise are smaller, the wear of the helical gears is relatively small, the service life is longer, and it can withstand greater loads, which is suitable for high-speed and heavy-load occasions. Both sets of gears use gears with the same module and the same number of teeth, and the transmission ratio is 1:1;

[0108] The knife bar 8 is provided with a rack seat 27 matched with the corresponding rack, the rack seat 27 is provided with a needle bearing I 28 matched with the bottom surface of each rack, and the bevel gear III 26 is then transmitted to the rack II 25 .

[0109] The tool rod 8 is provided with a guide rail seat 81 at the position where it contacts the boring tool assembly 5 for radial movement. A needle bearing II 82 is provided at the position where the guide rail seat 81 cooperates with the side wall of the boring tool assembly 5. The bevel gear III 26 is meshed with the rack II 25 to drive the boring tool seat 51 to move. The four sides of the boring tool seat 51 or the tool rod 8 are installed with needle guide rail seats 81 with needle bearings II 82, so that the boring tool assembly 5 and the tool rod 8 cavity are matched with a small gap. The needle roller guide has the advantages of compact structure, strong load-bearing capacity, high precision, and low friction resistance, so that the rack seat can slide on the tool rod 8 with high precision and stability.

[0110] In actual application, a water nozzle 52 is provided on the boring tool seat 51 to connect the internal cooling joint of the tool handle (i.e., the tool is internally cooled) through an internal water pipe 53. The boring tool clamp 50 is installed in the boring tool seat 51 and is tightened by two high-strength screws, with a simple structure and easy installation.

[0111] The overall transmission ratio of the boring tool is 1:2, that is, the boring tool clamp moves 2.5mm for one rotation of the motor. The motor rotates downward to make the ball screw 40 move back, the boring tool head moves up, and the boring hole diameter becomes smaller. Conversely, the motor rotates upward to make the ball screw 40 move forward, the boring tool head moves down, and the boring hole diameter becomes larger.

[0112] Furthermore, if Fig.11 When processing deep holes, the tool rod needs to be extended, so the entire tool structure should include: servo motor 1, synchronous belt 20, ball screw 40, boring tool clamp 50, hydraulic oil pipe 6, support seat 7, tool rod 8, extension rod 11, tool handle 12, etc.

[0113] Example:

[0114] Processing Fig.12 The inner hole A shown in the figure is similar to the shape of a vase, and is pre-drilled as shown in the figure. Fig.13 The bottom hole B shown; then Fig.14 As shown, the boring tool is inserted into the hole to the first step position to prepare for processing the front hole. The hydraulic switch is turned on to extend the hydraulic support column to contact the hole wall, support and position the tool rod part, and ensure its processing stability and concentricity. The inner hole is processed according to the normal processing procedure. At the same time, because the front end of the support is a ball structure, the workpiece cannot have a step surface greater than 30°. The hydraulic support can provide stable and large supporting force, and the hydraulic pressure can be adjusted according to the surface hardness of different workpieces to ensure that the tool rod will not give way due to force, which can effectively guarantee the processing accuracy, and the hydraulic force is stable, and the pressure can be stabilized at any extension length, and it can float freely with the change of the shape of the inner hole. Further, as Fig.15 As shown, the boring tool holder 50 on the boring tool assembly 5 is replaced with the reverse boring tool holder 54, and the reverse step processing of the position B is started, and finally the following is obtained: Fig.12 The inner hole A of the vase shape.

[0115] The above solution is only an illustration of a preferred embodiment, but is not limited thereto. When implementing the present invention, appropriate replacement and / or modification can be performed according to user needs.

[0116] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0117] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A large-diameter CNC deep-hole variable-diameter boring tool, characterized in that: include: A boring tool assembly located at the front end of the tool bar; A servo motor connected to the numerical control system for communication; A transmission assembly is used to connect the power output end of the servo motor to the boring tool assembly to control the radial movement of the boring tool assembly; A plurality of telescopic support components arranged on the circumference of the cutter bar and used to cooperate with the hole wall; a hydraulic unit cooperating with the telescopic support assembly; Wherein, the tool rod is provided with an endoscope probe at a position matching with the boring tool assembly.

2. The large-aperture CNC deep-hole variable-diameter boring tool according to claim 1, characterized in that: The telescopic support assembly is configured to include: A T-shaped support seat is embedded in the inside of the cutter bar, and an oil groove I is arranged in the extension end thereof; A support head is sleeved on the T-shaped support seat, and a guide column is arranged at the center thereof and can extend into the oil groove I; A housing that is connected to a T-shaped support seat through a fixing mechanism to limit the support head; There is a predetermined gap between the outer wall of the support head and the inner wall of the shell to obtain the oil groove II, and the support head is provided with a step end surface in an outwardly convex manner at one end close to the support seat, which is in a clearance fit with the gap of the inner wall of the shell; The oil grooves I and II are connected to an external hydraulic unit via a hydraulic control oil circuit arranged inside the cutter bar.

3. The large-aperture CNC deep-hole variable-diameter boring tool according to claim 2, characterized in that: A bull's eye ball is arranged at the top center of the support head.

4. The large-aperture CNC deep-hole variable-diameter boring tool according to claim 2, characterized in that: The top of the support head is provided with a plurality of wrench holes.

5. The large-aperture CNC deep-hole variable-diameter boring tool according to claim 2, characterized in that: The shell is provided with a thread matched with the module groove on the knife rod.

6. The large-aperture CNC deep-hole variable-diameter boring tool according to claim 1, characterized in that: The transmission assembly is configured to include: A thrust rod is arranged at the axis of the tool bar and is transmission-connected to the boring tool assembly through the transmission module I; A ball screw fixedly connected to the thrust rod, on which a screw nut connected by a thread is arranged; Transmission module II for connecting the lead screw nut to the power output end of the servo motor; Wherein, matching bearings are arranged at both ends of the screw nut.

7. The large-aperture CNC deep-hole variable-diameter boring tool according to claim 6, characterized in that: The transmission module I is configured to include: Rack I fixedly connected to the thrust rod; A helical gear I and a helical gear II are arranged side by side on the rack I through a rotating shaft and a bearing seat, and the helical gear I is in meshing state with the rack I; Rack II fixedly connected to the boring cutter assembly; A helical gear III that spatially connects the rack II with the helical gear II for transmission; Wherein, the knife bar is provided with a rack seat matched with the corresponding rack, and the rack seat is provided with a needle bearing I matched with the bottom surface of each rack; The tool rod is provided with a guide rail seat at the position where it contacts the boring tool assembly in radial movement, and a needle bearing II is provided at the position where the guide rail seat matches the side wall of the boring tool assembly.

8. A method for processing special-shaped deep holes, using the large-diameter CNC deep-hole variable-diameter boring tool as described in any one of claims 1 to 7, characterized in that: include: S1. Based on the overall transmission ratio of the boring tool, the CNC system drives the screw nut to rotate through the transmission module II through the forward or reverse rotation of the servo motor, thereby driving the thrust rod on the ball screw to move axially; S2. When the thrust rod moves axially, the boring cutter is driven to move radially through the transmission module I, so that the radial position of the boring cutter is changed, and the boring hole diameter is adjusted to pre-drill the bottom hole; S3. After the pre-drilling of the bottom hole is completed, the boring tool is inserted into the hole to the position of the first step, and the switch of the hydraulic unit is turned on, so that the telescopic support assembly extends outward under the action of the hydraulic pressure and contacts the hole wall of the bottom hole, and the processing operation of the front end hole is started; S4, replace the boring tool clamp on the boring tool assembly with a reverse boring tool clamp, process the reverse step, and complete the processing of the special-shaped hole; During the machining process, the machining situation is observed in real time through an endoscopic probe arranged on the boring tool assembly.

9. The method for machining special-shaped deep holes according to claim 8, characterized in that: The process of extending the support head in the telescopic support assembly is as follows: The hydraulic station of the hydraulic unit controls the hydraulic oil to enter the oil tank I. By increasing the amount of oil in the oil tank I, the guide column is provided with power, so that the support head integrally provided with the guide column extends outward. When the support head is extending, the hydraulic oil in the oil tank II flows back to the hydraulic station, leaving space for the support head to extend outward. The process of retracting the support head in the telescopic support assembly is as follows: The hydraulic station of the hydraulic unit enters oil tank II. Through the increase of oil volume in oil tank II, the hydraulic oil exerts force on the end face of the step, pressing the support head back to the initial position. When the support head is retracting, the hydraulic oil in oil tank I will flow back to the hydraulic station, leaving space for the support head to retract.

10. The method for machining a special-shaped deep hole according to claim 8, characterized in that: The working process of the transmission module I is as follows: When the thrust rod moves axially, it drives the rack I fixedly connected to the thrust rod to move axially synchronously; Helical gears I and II convert the axial motion of rack I into that of helical gear III, thereby causing rack II meshing with helical gear III to move radially. When the rack II moves axially, it drives the boring tool assembly fixedly connected to the rack II to move radially synchronously, thereby realizing the boring tool diameter changing operation during the drilling process.

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