Long-axis double-axis composite numerical control machine tool

Abstract

The invention provides a long-axis double-axis composite numerical control machine tool, and belongs to the technical field of machine tools. The problems that when an existing machine tool is used for machining a slender shaft, the machining precision is poor, and efficiency is low are solved. The long-shaft double-shaft composite numerical control machine tool comprises a machine table, a feeding device, a fixing device, two machining devices located at the two ends of the machine table respectively, a discharging device and two damping devices. The damping device comprises a damping ring, a seat body and a lifting mechanism, wherein the seat body is used for supporting the damping ring and enabling the damping ring to freely rotate and move in the radial direction, the lifting mechanism is used for driving the seat body to move up and down, and a center hole allowing the slender shaft blank to penetrate through is formed in the damping ring. According to the machining device, the feeding, fixing, machining and discharging integrated assembly line design is adopted, the two machining devices are adopted, the two ends of the slender shaft can be machined at the same time, the working efficiency is greatly improved, vibration generated when the slender shaft is machined can be greatly reduced through the damping device, and therefore the working efficiency and the yield are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of machine tools and relates to a long-axis double-axis composite numerically controlled machine tool. Background Art

[0002] A slender shaft refers to a shaft with a length-to-diameter ratio greater than 25. Since the slender shaft is long and has a small inner diameter, its rigidity is poor. When machining slender shafts, existing machine tools are susceptible to vibrations at high speeds due to the effects of cutting force, cutting heat, gravity, etc., leading to deformation or tool vibration, which seriously affects machining accuracy.

[0003] In order to solve the above problems, there are currently four main improvement methods. The first is to fix at both ends, that is, one end of the shaft is clamped by a chuck, and the other end is fixed by a tailstock elastic ejector. For example, the step S104 of a grinding method for a slender shaft workpiece disclosed in a Chinese patent application (application number: 202010661739.2) is to fix by pushing with two tops. For example, a motor long shaft processing machine tool disclosed in a Chinese patent application (application number: 202311293381.2) uses two clamping machines to fix the workpiece. The first method is to respectively support the two ends of the slender shaft, and then apply tension to the two ends of the slender shaft through two driving members, so as to straighten the slender shaft; the second method is to set a follower rest, which supports the workpiece near the cutting point of the tool and moves longitudinally with the tool rest slide, such as the slender shaft turning anti-vibration device disclosed in Chinese patent application (application number: 201721900106.2); the third method is to improve the tool to reduce the radial cutting force; the fourth method is to improve the cutting parameters and minimize the cutting amount. This method can also reduce the radial cutting force.

[0004] Although the above methods can reduce the vibration of the slender shaft and improve the accuracy to a certain extent, the first and second methods are only suitable for processing the middle and side parts of the slender shaft, but cannot process the end parts, which has great limitations; the third and fourth methods have high requirements on tools and cutting parameters, resulting in low processing efficiency, and the effect is extremely limited when the ratio of processing length to diameter is greater than 50. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems in the prior art and propose a long-axis dual-axis compound CNC machine tool. The technical problem to be solved by the present invention is: how to improve the machining accuracy and machining efficiency of slender shafts.

[0006] The object of the present invention can be achieved by the following technical solutions: A long-axis dual-axis compound CNC machine tool includes a machine platform, characterized in that it also includes: a feeding device, located at the front end of the machine platform, for placing the slender shaft blank and conveying the slender shaft blank to the processing position on the machine platform;

[0007] A fixing device, located on the machine platform and used for clamping and fixing the slender shaft blank and driving the slender shaft blank to rotate;

[0008] Two processing devices, located at both ends of the machine table and used for processing slender shaft blanks;

[0009] The unloading device is located at the rear end of the machine table and is used to take out and place the slender shaft after processing;

[0010] Two shock absorbing devices are respectively located between the two processing devices and the fixing device. The shock absorbing devices include a shock absorbing ring, a seat body for supporting the shock absorbing ring and enabling the shock absorbing ring to rotate freely and move in the radial direction, and a lifting mechanism for driving the seat body to move up and down. The shock absorbing ring has a center hole for the slender shaft blank to pass through.

[0011] When the present invention is working, the slender shaft blank to be processed is first transported to the fixing device of the machine table through the feeding device, and the two ends of the slender shaft are also passed through the shock-absorbing ring of the shock-absorbing device, and then the slender shaft is clamped and fixed by the fixing device. At this time, the shock-absorbing device drives the shock-absorbing ring to descend and makes the shock-absorbing ring hang on the slender shaft, and then the fixing device drives the slender shaft to rotate, and the two processing devices process the two ends of the slender shaft respectively. After the processing is completed, the fixing device stops rotating and releases the slender shaft, the shock-absorbing device drives the shock-absorbing ring to move up and separate from the slender shaft, and the unloading device moves the slender shaft to the storage bin. During the processing, the shock-absorbing ring contacts the slender shaft and rotates with it, and absorbs part of the vibration on the slender shaft through the shock-absorbing ring, and then continuously collides slightly with the shock-absorbing ring, and the vibration on the shock-absorbing ring and the vibration on the slender shaft are offset each other, thereby reducing the vibration of the slender shaft, so that the present invention can maintain high processing efficiency while still maintaining high processing accuracy and stability.

[0012] In the above-mentioned long-axis dual-axis compound CNC machine tool, the damping ring includes an annular ring body, and the two sides of the annular body have mounting parts protruding outward, the mounting parts are hollow cylindrical and located on the same axis as the annular body, the seat body has a hollow accommodating cavity and supporting parts located on both sides of the accommodating cavity, the supporting parts are provided with supporting holes connected to the accommodating cavity, the aperture of the supporting holes is larger than the outer diameter of the mounting part and smaller than the outer diameter of the annular body, the annular body is located in the accommodating cavity and the two mounting parts extend into the two supporting holes respectively. In this way, the damping ring can rotate freely in the accommodating cavity and can move freely in a small radial range.

[0013] In the above-mentioned long-axis dual-axis compound CNC machine tool, the ratio of the diameter of the central hole of the annular body to the diameter of the slender axis blank is between 1.25 and 2. In this way, the shock-absorbing ring can maintain a higher contact surface with the slender axis blank, and the shock-absorbing ring can maintain a higher collision frequency with the slender axis, so that the vibration energy transmission between the shock-absorbing ring and the slender axis blank is more frequent and the transmission effect is better, thereby ensuring the shock-absorbing effect.

[0014] In the above-mentioned long-axis dual-axis compound CNC machine tool, the annular body is also provided with an annular cavity arranged around the central hole, and a fluid damping medium is arranged in the annular cavity. When the damping ring rotates and vibrates with the slender axis, the fluid damping medium can effectively absorb a part of the vibration.

[0015] In the long-axis dual-axis compound CNC machine tool, the volume of the fluid damping medium is between 1 / 2 and 5 / 6 of the annular cavity. Within this range, the fluid damping medium has a better shock absorption effect.

[0016] In the above-mentioned long-axis dual-axis compound CNC machine tool, a plurality of annular shoulders evenly spaced along the circumference of the annular body are also provided in the annular cavity, and the annular shoulders divide the annular cavity into a plurality of interconnected cavities. The annular shoulders form damping holes, and when the fluid damping medium passes through, the vibration on the shock-absorbing ring can be further absorbed.

[0017] In the long-axis dual-axis composite CNC machine tool, a rubber layer is provided on the inner wall of the center hole of the annular body. The rubber layer has a certain elasticity, thereby reducing the impact of the shock-absorbing ring and the slender axis blank when they collide, so as to protect the surface of the slender axis.

[0018] In the above-mentioned long-axis dual-axis compound CNC machine tool, the fixing device includes two clamping mechanisms with chucks and two support frames, both of which are slidably connected to the guide rails, and the two support frames are located between the two clamping mechanisms. The two ends of the slender shaft blank are clamped and fixed by the clamping mechanism, and the middle part is supported by the two support frames, so that the slender shaft can remain straight and more stable when rotating at high speed.

[0019] In the above-mentioned long-axis dual-axis composite CNC machine tool, a positioning mechanism is also provided on the clamping mechanism, and the positioning mechanism includes a fixed seat, a positioning plate, and a cylinder for driving the positioning plate to swing up and down. The fixed seat is fixed on the top of the clamping mechanism, and the cylinder is fixed on the fixed seat. A connecting rod is also hinged on the fixed seat, and the positioning plate is hinged with the piston rod of the cylinder and the connecting rod respectively. The setting of the positioning mechanism can position the slender shaft blank during loading, ensuring the clamping accuracy of the clamping mechanism. Moreover, the fixed plate is lifted and lowered in an up-and-down swinging manner, so that after the slender shaft blank is positioned, the fixed plate is retracted in a manner of swinging upward and away from the slender shaft blank. There is no friction between the fixed plate and the end face of the slender shaft blank, and the retraction is smoother.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention adopts an integrated assembly line design for loading, fixing, processing and unloading, with a high degree of automation, and adopts two processing devices, which can process both ends of the slender shaft at the same time, greatly improving work efficiency.

[0022] 2. The present invention also provides two damping devices on the machine platform. The damping ring in the damping device is sleeved on the slender shaft. When the slender shaft is processed, the damping ring can follow the rotation and continuously collide with the damping ring slightly, thereby absorbing the vibration generated during the processing of the slender shaft and offsetting the vibration on the slender shaft after changing the direction and size of the vibration, thereby greatly reducing the vibration generated during the processing of the slender shaft. In this way, the processing device can appropriately improve the processing efficiency and still ensure the processing accuracy, thereby improving the work efficiency and yield rate.

[0023] 3. The present invention provides a plurality of annular cavities separated by annular bosses in the shock absorbing ring and fills the annular cavities with fluid damping medium, which can further consume the vibration transmitted from the slender shaft to the shock absorbing ring, reduce the collision impact between the shock absorbing ring and the slender shaft, and further improve the shock absorbing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of the machine;

[0026] Figure 3 It is a schematic diagram of the structure of the shock absorbing device;

[0027] Figure 4 is a front view of the shock absorbing device;

[0028] Figure 5 is along Figure 4 Sectional view along line AA;

[0029] Figure 6 is a side view of the shock absorbing device;

[0030] Figure 7 is along Figure 6 Sectional view along the midline BB;

[0031] Figure 8 It is a schematic diagram of the structure of the shock absorbing ring;

[0032] Fig. 9 It is a structural schematic diagram of the clamping mechanism and the positioning mechanism;

[0033] Fig.10 It is a side view of the clamping mechanism and the positioning mechanism.

[0034] In the figure, 1, feeding device; 2, machine table; 21, guide rail; 31, clamping mechanism; 32, support frame; 4, processing device; 5, unloading device; 6, shock absorbing device; 61, shock absorbing ring; 611; annular body; 612, mounting portion; 613, annular boss; 61a, center hole; 61b, annular cavity; 61c, damping hole; 62, seat body; 621, support portion; 62a, accommodating cavity; 62b, support hole; 63, rubber layer; 7, positioning mechanism; 71, fixed seat; 72, cylinder; 73, positioning plate; 74, connecting rod. DETAILED DESCRIPTION

[0035] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0036] A long-axis dual-axis compound CNC machine tool, such as Figure 1 As shown, it includes a loading device 1, a machine table 2, a fixing device, a processing device 4, a shock absorbing device 6 and a unloading device 5, wherein the loading device 1 is located at the front side of the machine table 2, the unloading device 5 is located at the rear side of the machine table 2, the fixing device is located on the machine table 2 and can be translated forward and backward along the X-axis of the machine table 2; there are two processing devices 4 and they are respectively located at both ends of the machine table 2, and the processing devices 4 are provided with milling cutters, drill bits and other processing equipment and can be translated relative to the machine table 2; there are also two shock absorbing devices 6, which are respectively located between the processing devices 4 and the fixing devices. When the present invention is working, the slender shaft blank placed on the loading device 1 is transported to the machine table 2 through the loading device 1, clamped and fixed by the fixing device, and the shock absorbing device 6 is in contact with the slender shaft, and then the processing devices 4 at both ends perform milling, drilling and other processing on the two ends of the slender shaft. After the processing is completed, the slender shaft is removed by the unloading device 5 and placed in the storage bin.

[0037] Specifically, Figure 2As shown, two guide rails 21 extending along the X-axis direction are arranged on the machine 2 at intervals, and the fixing device includes two clamping mechanisms 31 with chucks and two support frames 32. The clamping mechanisms 31 and the support frames 32 are both slidably connected to the guide rails 21, and the two support frames 32 are located between the two clamping mechanisms 31. Among them, the support frames 32 are each provided with a mounting hole, and a bearing is arranged in the mounting hole. The inner hole of the bearing is slightly larger than the diameter of the slender shaft. The clamping mechanism 31 near the front end of the machine 2 is connected to a driving motor in a transmission manner, and serves as an active disk, which can actively drive the chuck on the clamping mechanism 31 to rotate. The other clamping mechanism 31 is not provided with a driving motor and serves as a driven disk. When the slender shaft passes through the feeding device 1 and is arranged on the fixing device, the two clamping mechanisms 31 clamp and fix the slender shaft, and drive the slender shaft to rotate at a high speed through the driving motor for processing. The two support frames 32 in the middle form a support for the middle part of the slender shaft, so that the slender shaft remains in a straight state, so as to reduce the deformation and vibration of the slender shaft during processing and improve the processing accuracy.

[0038] like Figure 2 , Figure 3 As shown, the shock absorbing device 6 includes a mounting seat, a seat body 62 and a shock absorbing ring 61. The mounting seat is slidably connected to the guide rail 21. The mounting seat is connected to the seat body 62 through a lifting mechanism, so that the shock absorbing device 6 can translate in the X-axis direction of the machine table 2 and can be lifted in the Z-axis direction. In this embodiment, the lifting mechanism adopts a screw transmission structure. Figures 3 to 8As shown, the shock-absorbing ring 61 includes an annular ring body 611, which has a center hole 61a for the slender shaft to pass through. The aperture of the center hole 61a is slightly larger than the diameter of the slender shaft. Preferably, the ratio of the aperture of the center hole 61a to the diameter of the slender shaft blank to be processed is between 1.25 and 2. Both sides of the annular body 611 are provided with mounting portions 612 protruding outward, the mounting portions 612 are hollow cylindrical and are located on the same axis as the annular body 611, the seat body 62 is formed by two half shells, and has a hollow accommodating chamber 62a, both sides of the accommodating chamber 62a are provided with supporting portions 621, the supporting portions 621 are provided with supporting holes 62b that penetrate the accommodating chamber 62a, the aperture of the supporting hole 62b is slightly larger than the outer diameter of the mounting portion 612 and smaller than the outer diameter of the annular body 611, the two mounting portions 612 of the shock-absorbing ring 61 are respectively mounted in the two supporting holes 62b, so that the annular body 611 is located in the accommodating chamber 62a, can rotate freely and can move freely in a small range in the radial direction, and the axial movement of the annular body 611 is limited by the supporting portions 621 on both sides. When the slender shaft is not clamped, the lifting mechanism first slightly lifts the seat body 62 to facilitate the passage of the slender shaft. When the slender shaft is clamped and fixed, the lifting mechanism lowers the seat body 62 again, so that the shock-absorbing ring 61 is hung on the slender shaft and supported only by the slender shaft. At this time, the shock-absorbing ring 61 is tightly attached to the slender shaft under the action of gravity; when the slender shaft rotates at high speed and is processed, the shock-absorbing ring 61 will also be driven by the slender shaft and rotate around the slender shaft. At this time, the vibration generated by the slender shaft is directly transmitted to the shock-absorbing ring 61, so that high-frequency mild collisions are continuously generated between the shock-absorbing ring 61 and the slender shaft. Since the circumference of the inner hole of the shock-absorbing ring 61 is relatively long and there is a certain amount of sliding between the shock-absorbing ring 61 and the slender shaft, the rotation speed of the slender shaft is relatively high, and the rotation speed of the shock-absorbing ring 61 is relatively low. There is a certain misalignment between the two. The vibration transmitted to the shock-absorbing ring 61 will not resonate with the vibration of the slender shaft, but will continuously adjust and reach a dynamic balance when it continuously collides with the slender shaft, so that the vibration on the shock-absorbing ring 61 is transmitted back to the slender shaft and offsets the vibration on the slender shaft, thereby greatly reducing the vibration of the slender shaft, making the processing of the slender shaft smoother and with higher processing accuracy.

[0039] Furthermore, as shown in the figure, the annular body 611 is provided with an annular cavity 61b arranged and sealed around the central hole 61a thereof, and a fluid damping medium such as water or hydraulic oil can be injected into the annular cavity 61b, and the volume of the damping medium is between 1 / 2 and 5 / 6 of the annular cavity 61b. In this embodiment, a plurality of annular bosses 613 evenly spaced along the circumference of the annular body 611 are also provided in the annular cavity 61b, and damping holes 61c are formed on the annular bosses 613, so that the annular cavity 61b is divided into a plurality of cavities connected by the damping holes 61c. In this embodiment, the number of the annular bosses 613 is six. When the damping ring 61 rotates with the slender shaft and continuously collides with the slender shaft, the damping medium in the annular cavity 61b will also continuously flow and consume kinetic energy, thereby reducing the impact when the damping ring 61 collides with the slender shaft.

[0040] Furthermore, a rubber layer 63 is provided on the inner wall of the central hole 61 a of the annular body 611 , so as to further reduce the impact when colliding with the slender shaft and avoid damage to the surface of the slender shaft.

[0041] Further, such as Fig. 9 , Fig.10 As shown, the two clamping mechanisms 31 are also provided with a positioning mechanism 7, which includes a fixed seat 71, a positioning plate 73 and a cylinder 72 for controlling the up and down swinging of the positioning plate 73. The fixed seat 71 is in the shape of an L-shaped plate, and two long waist-shaped holes are spaced apart on the flat surface of the fixed seat 71. The fixed seat 71 is fixed to the top of the clamping mechanism 31 by two fixing bolts cooperating with the waist-shaped holes, and the position can be adjusted according to the length of the slender shaft. The cylinder 72 is fixed on the vertical plane of the fixed seat 71 along the length direction of the machine table 2. A connecting rod 74 is also hinged on the fixed seat 71. The connecting rod 74 is located below the cylinder 72. The other end of the connecting rod 74 is hinged to the middle part of the positioning plate 73, and the upper end of the positioning plate 73 is hinged to the piston rod, so that the cylinder 72 only needs a short stroke to realize a large-scale up and down swing of the positioning plate 73 to block the forward path of the slender shaft. In the present invention, both positioning mechanisms 7 can work independently. One of the positioning mechanisms 7 is selected for positioning according to the length of the slender shaft to be processed. When positioning the short shaft, the positioning mechanism 7 at the front end of the machine 2 is activated, and when positioning the long shaft, the positioning mechanism 7 at the rear end of the machine 2 is activated.

[0042] The working process of the present invention is as follows: first, the shock absorbing device 6 drives the shock absorbing ring 61 to move upward, the positioning mechanism 7 drives the positioning plate 73 to swing downward, the feeding device 1 drives the slender shaft blank to move toward the fixing device, so that the slender shaft passes through the shock absorbing ring 61, the clamping mechanism 31 and the support frame 32 and abuts against the positioning plate 73, then the clamping mechanism 31 clamps and fixes the slender shaft, the positioning mechanism 7 drives the positioning plate 73 to move upward to avoid processing interference, then the shock absorbing device 6 drives the shock absorbing ring 61 to move downward, so that the shock absorbing ring 61 is hung on the slender shaft blank, and then the two ends of the slender shaft are turned, drilled and milled by the processing device 4, after the processing is completed, the clamping mechanism 31 releases the slender shaft, the shock absorbing device 6 drives the shock absorbing ring 61 to move upward, so that the shock absorbing ring 61 is separated from the slender shaft, and finally the slender shaft is moved to the storage bin of the unloading device 5 by the unloading device 5. The above process of the present invention can be fully automated, with high processing efficiency, high processing accuracy and good stability.

[0043] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0044] Although the present invention uses the terms such as loading device 1, machine table 2, guide rail 21, clamping mechanism 31, support frame 32, positioning mechanism 7, processing device 4, unloading device 5, shock absorbing device 6, etc. more frequently, it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A long-axis dual-axis compound CNC machine tool, comprising a machine platform (2), characterized in that: Also includes: A feeding device, located at the front end of the machine table (2), used for placing the slender shaft blank and conveying the slender shaft blank to a processing position on the machine table (2); A fixing device, located on the machine platform (2) and used for clamping and fixing the slender shaft blank; Two processing devices (4), respectively located at two ends of the machine platform (2) and used for processing the slender shaft blank; A material removal device (5), located at the rear end of the machine table (2), for taking out and placing the elongated shaft after processing; Two shock absorbing devices (6), the shock absorbing devices (6) are respectively located between the two processing devices (4) and the fixing device, the shock absorbing devices (6) comprising a shock absorbing ring (61), a seat body (62) for supporting the shock absorbing ring (61) and enabling the shock absorbing ring (61) to rotate freely and move in a radial direction, and a lifting mechanism for driving the seat body (62) to move up and down, and the shock absorbing ring (61) has a central hole (61a) for the slender shaft blank to pass through.

2. The long-axis dual-axis compound CNC machine tool according to claim 1, characterized in that: The damping ring (61) comprises an annular ring body (611), and both sides of the annular body (611) are provided with mounting portions (612) protruding outward, and the mounting portions (612) are hollow cylindrical and are located on the same axis as the annular body (611); the seat body (62) comprises a hollow accommodating cavity (62a) and supporting portions (621) located on both sides of the accommodating cavity (62a); the supporting portions (621) are provided with supporting holes (62b) connected to the accommodating cavity (62a); the aperture of the supporting holes (62b) is larger than the outer diameter of the mounting portions (612) and smaller than the outer diameter of the annular body (611); the annular body (611) is located in the accommodating cavity (62a), and the two mounting portions (612) extend into the two supporting holes (62b) respectively.

3. The long-axis dual-axis compound CNC machine tool according to claim 1 or 2, characterized in that: The ratio of the diameter of the central hole (61a) of the annular body (611) to the diameter of the slender shaft blank is between 1.25 and 2.

4. The long-axis dual-axis compound CNC machine tool according to claim 2, characterized in that: The annular body (611) is also provided with an annular cavity (61b) arranged around the central hole (61a), and a fluid damping medium is arranged in the annular cavity (61b).

5. The long-axis dual-axis compound CNC machine tool according to claim 4, characterized in that: The volume of the fluid damping medium is between 1 / 2 and 5 / 6 of the annular cavity (61b).

6. The long-axis dual-axis compound CNC machine tool according to claim 4 or 5, characterized in that: A plurality of annular bosses (613) are also arranged in the annular cavity (61b) and are evenly spaced along the circumference of the annular body (611). The annular bosses (613) divide the annular cavity (61b) into a plurality of cavities that are interconnected.

7. The long-axis dual-axis compound CNC machine tool according to claim 6, characterized in that: A rubber layer (63) is also provided on the inner wall of the central hole (61a) of the annular body (611).

8. The long-axis dual-axis compound CNC machine tool according to claim 1, 2 or 4, characterized in that: The fixing device comprises two clamping mechanisms (31) with chucks and two support frames (32); the clamping mechanisms (31) and the support frames (32) are both slidably connected to the guide rail (21), and the two support frames (32) are located between the two clamping mechanisms (31).

9. The long-axis dual-axis compound CNC machine tool according to claim 8, characterized in that: The clamping mechanism (31) is also provided with a positioning mechanism (7), the positioning mechanism (7) comprising a fixed seat (71), a positioning plate (73) and a cylinder (72) for driving the positioning plate (73) to swing up and down, the fixed seat (71) is fixedly arranged on the top of the clamping mechanism (31), the cylinder (72) is fixedly arranged on the fixed seat (71), a connecting rod (74) is also hinged on the fixed seat (71), and the positioning plate (73) is respectively hinged to the piston rod of the cylinder (72) and the connecting rod (74).

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