Multi-station cam roller numerical control rotary table driven coaxially and synchronously in series

Abstract

The application discloses a coaxial series synchronous driving multi-station cam roller numerical control rotary table, and belongs to the field of high-end numerical control machine tool core function components; the rotary table comprises a base, an input driving assembly, at least two groups of coaxial series cam roller transmission units, corresponding output workstations and an integrated common cavity lubricating assembly; a single main input shaft is connected with multiple groups of consistent phase cam surfaces, and multiple groups of needle bearing output assemblies are synchronously driven to rotate, so that multi-station synchronous indexing is realized; in cooperation with the common cavity lubricating system and the built-in angle detection compensation structure, the problems of poor synchronism, large cumulative error, bulky structure and complicated maintenance caused by the parallel connection of multiple independent rotary tables in the existing multi-station rotary table are solved; the single-station repeated positioning precision of the application is less than or equal to 4 arc seconds, and the inter-station synchronous error is less than or equal to 2 arc seconds; compared with the traditional parallel type multi-station scheme, the synchronous precision is greatly improved, the structure is more compact, and the application can be widely applied to the efficient batch precision machining scene of multi-spindle machining centers.

Description

Technical Field

[0001] This invention relates to the technical field of core functional components of CNC machine tools, and in particular to a multi-station cam roller CNC rotary table with coaxial series synchronous drive. Background Technology

[0002] As the core functional components of the fourth and fifth axes of CNC machine tools, the CNC rotary table is a key component for realizing multi-degree-of-freedom machining of complex curved surface parts, accounting for approximately 25% of the total cost of the CNC machine tool. Currently, the mainstream transmission structures in the industry are divided into two types: worm gear type and cam roller type. Worm gear rotary tables are prone to wear and clearance after long-term operation, resulting in poor accuracy retention. Cam roller rotary tables adopt preloaded zero-backlash rolling transmission, eliminating sliding friction, and offering superior accuracy retention and transmission efficiency, making them the mainstream development direction for high-end rotary tables.

[0003] With increasing demands for processing efficiency, multi-spindle machining centers are becoming increasingly common, requiring multi-station CNC rotary tables to achieve batch synchronous processing. Current multi-station solutions typically employ multiple independent CNC rotary tables installed side-by-side, each driven by a separate motor, which has the following drawbacks: 1. Synchronization of multiple independently driven units is difficult to guarantee, and the phase error between workstations is large, resulting in poor consistency of part processing and unstable pass rate; 2. Multiple rotary tables are independently configured with motors, transmission pairs and lubrication systems, resulting in a bulky overall structure, occupying a large amount of machine tool space and incurring high costs; 3. The maintenance workload of multiple independent systems is large, and lubrication and precision calibration need to be performed on each system individually, resulting in low operation and maintenance efficiency.

[0004] Currently, most multi-station rotary tables in existing enterprises adopt gear indexing or direct drive structures. Gear indexing has limitations in indexing levels and cannot achieve continuous rotation; direct drive rotary tables are costly and lack sufficient cutting rigidity, making them unsuitable for heavy-duty cutting scenarios. Meanwhile, existing cam roller rotary tables are mostly single-station structures, lacking mature multi-station solutions with coaxial series synchronous drives, and cannot meet the high-efficiency machining needs of multi-spindle machine tools. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a coaxial series synchronous drive multi-station cam roller CNC rotary table. By connecting multiple sets of phase-consistent cam roller transmission pairs in series through a single input shaft, high-precision synchronous indexing of multiple stations is achieved. It integrates a common cavity lubrication system and a unified precision compensation mechanism to improve the synchronization accuracy, structural compactness and ease of operation and maintenance of the multi-station rotary table.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A multi-station cam roller CNC rotary table with coaxial series synchronous drive includes a base, an input drive assembly, at least two sets of cam roller transmission units arranged coaxially in series, an output worktable corresponding to each of the cam roller transmission units, and an integrated common cavity lubrication assembly. The input drive assembly includes a servo motor and a main input shaft that runs coaxially through all cam roller drive units, with the servo motor being drive-connected to one end of the main input shaft; Each of the cam roller transmission units includes an arc-shaped cam fixedly sleeved on the main input shaft and a needle roller bearing output assembly that meshes with the arc-shaped cam without clearance. The output end of the needle roller bearing output assembly is coaxially fixedly connected to the corresponding output worktable. The arc-shaped cams of all cam roller drive units are arranged sequentially along the main input shaft axis and their indexing curves are completely in phase. The integrated common cavity lubrication assembly is located inside the base and is connected to the meshing area of ​​all cam roller drive units.

[0007] In a preferred embodiment, the needle roller bearing output assembly includes an output shaft, a plurality of needle roller bearing units evenly arranged circumferentially along the output shaft, and an output end flange; the needle roller bearing units are fixed to the end face of the output shaft by pins, and the rolling surfaces of all the needle roller bearings mesh with the annular contour surface of the arc cam; the output end flange is coaxially fixed to the output shaft, and the output worktable is locked to the output end flange by bolts.

[0008] In a preferred embodiment, the needle roller bearing unit adopts a forged blank integral needle roller structure, the concentricity of the grinding of the roller and the bushing is ≤0.5μm, and the overall radial runout of the assembled needle roller bearing is ≤1μm; the number of needle roller bearing units in each set of needle roller bearing output components is 8~12 sets, which are distributed at equal angles along the circumference of the output shaft.

[0009] In a preferred embodiment, the integrated common cavity lubrication assembly includes an oil storage cavity disposed at the bottom of the base, an oil supply path connecting the meshing areas of all cam roller drive units, an oil return path, and a circulating filter unit; the oil supply path is provided with a throttling nozzle at the meshing inlet of each set of arc-shaped cams, the oil return path converges into the oil storage cavity, and the circulating filter unit is disposed between the oil storage cavity and the oil supply path.

[0010] In a preferred embodiment, a phase adjustment sleeve is provided between two adjacent arc-shaped cams on the main input shaft. The phase adjustment sleeve cooperates with the main input shaft through a flat key to finely adjust the circumferential phase difference between adjacent arc-shaped cams, ensuring that the synchronization error of the indexing start position of all output worktables is ≤2 arcseconds.

[0011] In a preferred embodiment, each output workbench is equipped with a built-in disc spring brake assembly. The disc spring brake assembly includes a brake seat fixed in the base, a brake disc sleeved on the output shaft, an axially arranged disc spring assembly, and a hydraulic release unit. Under normal conditions, the disc spring assembly pushes the brake seat to press the brake disc to achieve locking. When the hydraulic release unit is energized, it pushes the disc spring assembly to compress and release the locking mechanism.

[0012] In a preferred embodiment, each output workbench is equipped with an absolute angle detection unit at the end of its output shaft, and the signals from all angle detection units are connected to the same control module. The control module performs overall accuracy compensation on the main input shaft through a servo motor based on multi-station angle feedback data. After compensation, the single-station repeatability positioning accuracy is ≤4 arcseconds, and the synchronization error between stations is ≤2 arcseconds.

[0013] In a preferred embodiment, the base is an integrally cast box structure, and all cam roller drive units are installed in the same box cavity; the top of the base is provided with a mounting flange surface corresponding to each output worktable, and the center distance between adjacent output worktables is consistent with the center distance of the multi-spindles of the matching machine tool.

[0014] In a preferred embodiment, the output shaft is supported in the base by a pair of tapered roller bearings mounted back to back, and the preload of the bearings is adjusted by end locking nuts; a labyrinth seal structure is provided between the output shaft and the base, which, together with the common cavity lubrication assembly, forms a positive pressure seal to prevent cutting fluid and dust from entering the interior.

[0015] In a preferred embodiment, the number of cam roller transmission units is 2 to 4, corresponding to 2 to 4 output worktables; all output worktables have the same diameter, load-bearing capacity and indexing accuracy level, which is suitable for synchronous batch processing scenarios of multi-spindle machining centers.

[0016] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art are as follows: 1. High synchronization accuracy: It adopts a single main input shaft and multiple sets of cam roller transmission units connected in series. All stations are driven by the same power source, and the phase consistency is naturally controllable. With the help of the phase adjustment sleeve for fine adjustment, the synchronization error between stations can be controlled within 2 arcseconds, which is far superior to the traditional multi-unit parallel scheme and significantly improves the consistency of batch processed parts.

[0017] 2. Compact structure: All transmission units are integrated into the same base housing, sharing a single drive system and lubrication system. The overall volume is significantly reduced compared to multiple independent rotary tables connected in parallel, making it more suitable for the limited installation space of multi-spindle machine tools, while also reducing manufacturing costs.

[0018] 3. Excellent precision retention: It adopts forged high-precision needle roller bearings and zero-backlash cam roller transmission, combined with common cavity forced circulation lubrication, which effectively reduces wear, and the precision decay is small after long-term operation. It does not require frequent calibration and its service life is significantly improved compared with traditional solutions.

[0019] 4. Convenient operation and maintenance: The unified lubrication system and detection and control system can cover all workstations with only one maintenance, greatly reducing the workload of operation and maintenance and adapting to the efficient management needs of large-scale production lines. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic cross-sectional view of the overall structure of the turntable of the present invention; Figure 2 This is a schematic diagram of the meshing structure of a cam roller drive unit; Figure 3 This is a schematic diagram of the oil circuit layout for an integrated common cavity lubrication assembly. Among them: 1. Base; 2. Input drive components; 21. Servo motor; 22. Main input shaft; 3. Cam roller drive unit; 31. Arc cam; 32. Output shaft; 33. Needle roller bearing unit; 34. Output end flange; 4. Output workbench; 5. Phase adjustment sleeve; 6. Integrated common cavity lubrication assembly; 61. Oil reservoir; 62. Oil delivery circuit; 63. Oil return circuit; 64. Circulating filter unit; 7. Brake components; 8. Angle detection unit. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0025] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0026] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] The core concept of this invention lies in using a single main input shaft 22 coaxially connected in series with multiple sets of cam roller transmission units 3. Through unified driving, unified lubrication, and unified detection and compensation, high-precision synchronous indexing across multiple workstations is achieved, solving the problems of poor synchronization, bulky structure, and cumbersome operation and maintenance of traditional multi-parallel rotary tables. The following describes the specific structure, assembly process, and implementation effects in detail through several embodiments.

[0029] Example 1 like Figure 1 As shown, this embodiment is a standard dual-station vertical coaxial tandem cam roller CNC rotary table (NC250 type) adapted to a dual-spindle vertical machining center. It is installed vertically as a whole and includes a base 1, an input drive assembly 2, two sets of cam roller transmission units 3, two output worktables 4, and an integrated common cavity lubrication assembly 6.

[0030] In this embodiment, the base 1 is integrally cast from HT300 gray cast iron, forming a one-piece box structure with an inner cavity length of 720mm, a width of 320mm, and a height of 450mm. Two standard mounting flanges are machined on the top of the base. The two output worktables 4 are symmetrically arranged left and right along the axial direction of the main input shaft 22, with a center distance of 400mm, matching the spindle spacing of mainstream dual-spindle machining centers in the industry. They can be directly locked and installed using T-slot bolts, corresponding to the one-piece box and matching mounting structure of claim 8.

[0031] The output worktable 4 is a one-piece cast circular flange structure with a diameter of 250mm and made of HT250 stainless steel. The upper surface is machined with four radial T-slots and a φ120mm center locating stop for clamping workpieces. The lower surface is machined with a locating step and eight sets of M10 threaded mounting holes. It is coaxially locked to the output flange 34 using hexagonal bolts, with a stop fit accuracy of H7 / h6, ensuring coaxiality ≤0.005mm. The upper surface of the worktable is 15mm higher than the top surface of the base, matching the height of the spindle end face of the dual-spindle machining center.

[0032] The input drive assembly 2 includes a servo motor 21 and a main input shaft 22. The servo motor 21 is a 1.5kW absolute servo motor with a rated speed of 3000rpm, and is connected to the left end of the main input shaft 22 via a diaphragm coupling. The main input shaft 22 is made of 40Cr steel with a diameter of 45mm, and extends horizontally through the inner cavity of the base. Both ends are supported on the sidewalls of the base by a pair of angular contact ball bearings. The bearing preload is adjusted by the end lock nuts to ensure axial movement ≤0.002mm.

[0033] Two sets of cam roller drive units 3 are arranged symmetrically in series along the main input shaft 22. Each drive unit includes an arc-shaped cam 31 and a needle roller bearing output assembly. The arc-shaped cam 31 is made of 20CrMnTi carburized and quenched material with a surface hardness of HRC58-62, and is fixed to the main input shaft 22 by a flat key. The indexing curves of the two arc-shaped cams are sinusoidal acceleration motion curves with a lift angle of 270°, a dwell angle of 90°, and 8 equal indexing positions. The installation phases are completely consistent, corresponding to the coaxial series and phase-consistent core structure of claim 1.

[0034] like Figure 2 As shown ( Figure 2(This is a schematic diagram of the meshing end face from an axial perspective along the main input shaft 22). The needle roller bearing output assembly includes an output shaft 32, 10 sets of needle roller bearing units 33, and an output end flange 34. The main input shaft 22 is arranged horizontally, and the output shaft 32 is arranged vertically. Their axes are spatially perpendicular and staggered (not coplanar or intersecting), which is a typical staggered shaft cam roller drive structure. The output shaft 32 is made of 42CrMo heat-treated material and is supported in a base by a pair of back-to-back tapered roller bearings. The bearing preload is adjusted by the end lock nut to ensure radial runout ≤0.003mm.

[0035] The needle roller bearing unit 33 consists of a pin and a needle roller bearing body. The pin is vertically fixed to the lower end face of the output shaft 32. The needle roller bearing body is interference-fitted with the pin through an inner ring and can rotate freely around the pin's own axis. Ten sets of needle roller bearing units 33 are evenly distributed at an angle of 36° along the circumference of the lower end face of the output shaft 32. The outer cylindrical surfaces of all the needle roller bearing bodies together form a meshing surface that matches the annular contour of the arc-shaped cam 31. When the arc-shaped cam 31 rotates with the main input shaft 22 around the horizontal axis, its helical annular contour sequentially pushes each needle roller bearing unit 33, driving the output shaft 32 to perform indexing rotation around the vertical axis. The two are in pure rolling, backlash-free, preload-controlled meshing, with the preload controlled at 0.02~0.03mm. There is no sliding friction during the transmission process, corresponding to the needle roller bearing output assembly structure of claim 2.

[0036] In this embodiment, the needle roller bearing unit 33 adopts a one-piece forged blank structure. Both the rollers and the bushings are made of GCr15 bearing steel forged blanks, which are processed by spheroidizing annealing, rough grinding, fine grinding, and ultra-precision grinding. Finally, the concentricity of the rollers and bushings is ≤0.5μm, and the overall radial runout of the assembled needle roller bearing is ≤1μm. The influence of a single set of needle roller bearings on the indexing accuracy of the turntable is controlled within 2 arcseconds, which corresponds to the technical features of the forged high-precision needle roller bearing in claim 3. The output end flange 34 is locked to the top of the output shaft with hexagonal socket bolts, and the output worktable 4 is locked to the output end flange after being positioned by a stop.

[0037] A phase adjustment sleeve 5 is installed between the two arc-shaped cams 31 on the main input shaft 22. The transmission chain and adjustment principle of the three are as follows: The phase adjustment sleeve 5 is a quenched and tempered 45 steel part, sleeved on the main input shaft 22, located between the two arc-shaped cams 31; both ends of the adjustment sleeve body are machined with fine teeth, the tooth pitch corresponding to a circumferential angle of 1 angular minute. The opposite inner end faces of the two arc-shaped cams are also machined with matching fine teeth. The three transmit torque through the meshing of the teeth. The complete transmission chain is: main input shaft 22 → flat key → phase adjustment sleeve 5 → teeth → arc-shaped cam 31 → needle roller bearing unit 33 → output shaft 32 → output table 4. The circumferential phase of the arc-shaped cam 31 directly determines the indexing starting angle of the output table 4, and the phase difference between the two arc-shaped cams corresponds to the indexing starting position difference between the two output tables. During assembly and adjustment, first loosen the axial locking nut of the arc-shaped cam, rotate the phase adjustment sleeve 5, and by changing the meshing position of the end face teeth, the circumferential phase difference between the two arc-shaped cams 31 can be finely adjusted; with the help of the laser interferometer to detect the indexing start position of the two output worktables in real time, after calibrating to the point where the synchronization error is ≤2 arcseconds, tighten the axial nut to fix the position of the arc-shaped cam, and complete the phase synchronization calibration, which corresponds to the phase adjustment structure of claim 5.

[0038] Each output shaft 32 is equipped with a built-in disc spring brake assembly 7. The brake assembly includes a brake seat fixed to the inner wall of the base, a brake disc sleeved on the output shaft, a 12-piece axially stacked disc spring assembly, and a hydraulic release unit. Under normal conditions, the disc spring assembly extends, pushing the brake seat to lock the brake disc by end face pressing, with a maximum braking torque of 1200 N·m, ensuring vibration resistance during cutting. During indexing rotation, the hydraulic release unit introduces 4 MPa pressure oil, pushing the disc spring assembly to compress and release the brake disc, with a release response time ≤0.2s, corresponding to the built-in disc spring brake structure of claim 6.

[0039] Both output shafts 32 are equipped with absolute circular gratings as angle detection units 8 at their lower ends, with a grating resolution of 0.1 arcseconds. All grating signals are connected to the same motion control module. Based on multi-station angle feedback data, the control module uses a BP neural network prediction algorithm to perform overall compensation and correction on the input commands of the servo motor. The specific implementation method is as follows: Hardware architecture: The motion control module adopts a PLC + motion control card architecture, and the algorithm is deployed in the motion control card, requiring no additional hardware.

[0040] Network Structure: A three-layer feedforward backpropagation neural network is adopted, consisting of an input layer, a hidden layer, and an output layer. The input layer has 5 nodes, and the input parameters are: the left station angle error in the current sampling period, the right station angle error in the current sampling period, the current speed of the servo motor, the current lubricating oil temperature, and the compensation amount in the previous period. The hidden layer has 10 nodes and uses the sigmoid activation function. The output layer has 1 node, and the output is the servo motor angle compensation amount for the next sampling period.

[0041] Offline training: 10,000 sets of sample data were collected in advance under different speed, load and oil temperature conditions. The sample inputs were the above 5 types of parameters, and the sample labels were the actual measured angle deviation values ​​of the next cycle. The gradient descent method was used to train the network offline. The training error converged to within 0.01 arcseconds, and the trained network weight model was obtained and solidified into the control module.

[0042] Real-time compensation process: During system operation, the actual angle values ​​of the two workstations are collected in real time with a sampling period of 1ms using two absolute circular gratings, and the deviation from the theoretical indexing position is calculated. The deviation value, along with the current speed, oil temperature, and compensation amount of the previous cycle, is input into the trained BP neural network model to predict and output the angle compensation amount for the next cycle. The compensation amount is superimposed on the position command of the servo motor to uniformly correct the motion of the main input shaft, thereby achieving synchronous accuracy compensation for the two workstations.

[0043] According to third-party testing, the single-station repeatability of the product in this embodiment is ≤4 arcseconds, the positioning accuracy is ≤15 arcseconds, and the synchronization error between stations is ≤2 arcseconds, which corresponds to and supports the unified testing and accuracy compensation technical features of claim 7.

[0044] like Figure 3 As shown, the integrated common cavity lubrication assembly 6 includes an oil reservoir 61, an oil supply path 62, an oil return path 63, and a circulating filter unit 64. The oil reservoir 61, integrated into the bottom of the base, has a volume of 2.5L and is filled with ISO VG68 precision machine tool lubricating oil. The oil supply path leads from the oil reservoir, is pressurized by the circulating filter unit, and then splits into two paths, each leading to the meshing inlet of two sets of arc-shaped cams. Each inlet is equipped with a throttling nozzle with a flow rate of 0.5L / min to ensure that the lubricating oil is evenly sprayed onto the meshing surfaces of the cams and needle rollers. The oil return path collects the lubricating oil from the oil collection groove at the bottom of the base cavity, guiding the used lubricating oil back to the oil reservoir, forming a closed-loop circulation. The circulating filter unit has a filtration accuracy of 5μm and a built-in cooling coil, which can control the oil temperature below 40℃, ensuring minimal thermal deformation of the transmission pair, corresponding to the common cavity lubrication structure of claim 4.

[0045] A labyrinth seal structure is provided between the output shaft 32 and the upper end cover of the base. Combined with the internal micro-positive pressure (0.02MPa) created by the lubrication system, this effectively prevents external cutting fluid and metal dust from entering the housing, extending the service life of the transmission pair and corresponding to the bearing support and sealing structure of claim 9. After durability testing, the accuracy decay of the turntable in this embodiment is ≤1 arcsecond after 8000 hours of continuous operation, eliminating the need for recalibration of the clearance.

[0046] The product in this embodiment is mainly used for batch precision milling and drilling of 3C product parts and automotive parts using dual spindles. Compared with the traditional solution of two independent rotary tables in parallel, the overall installation width is reduced by 42%, the synchronization accuracy is improved by 65%, the maintenance workload is reduced by 60%, and the overall processing efficiency is improved by 35%.

[0047] Example 2 This embodiment is a three-station coaxial series cam roller CNC rotary table (NC180 type) adapted to a three-spindle high-speed drilling and tapping center. The overall structure and principle are the same as in Embodiment 1. The core difference is that the number of cam roller transmission units 3 and output worktables 4 is 3 sets, which is used to verify the extended applicability of 2 to 4 sets of workstations.

[0048] In this embodiment, the inner cavity of the base 1 is 950mm long, the diameter of each of the three output worktables 4 is 180mm, and the center distance between adjacent worktables is 280mm, matching the standard spindle spacing of a three-spindle high-speed drilling and tapping center. Three identical arc-shaped cams 31 are connected in series on the main input shaft 22, and a set of phase adjustment sleeves 5 is set between each adjacent arc-shaped cam 31. During assembly, the phase is calibrated group by group from the middle position to both sides, and finally the synchronization error between the indexing start positions of the three positions is ≤2.5 arcseconds.

[0049] The needle roller bearing output assembly is configured with eight needle roller bearing units 33, distributed at 45° angles along the circumference of the output shaft 32, to suit the compact structure of small-sized turntables. The needle roller bearings also adopt a precision grinding process for forged blanks, with a roller and bushing concentricity of ≤0.5μm, ensuring the consistency of overall indexing accuracy.

[0050] The integrated common cavity lubrication assembly 6 has three oil supply paths, each corresponding to one of the three meshing areas. The flow rate of each throttling nozzle is 0.3L / min. The return oil path is uniformly collected in the bottom oil storage chamber and shares a common set of circulating filter units to ensure that the lubrication conditions and oil temperature of all workstations are completely consistent, avoiding accuracy deviations caused by lubrication differences.

[0051] The disc spring brake assembly 7 in this embodiment has a maximum braking torque of 600 N·m, suitable for light-load cutting scenarios in drilling and tapping. The angle detection unit signals of the three stations are uniformly connected to the same control module, employing the same BP neural network compensation algorithm as in Embodiment 1 to achieve synchronous accuracy compensation for the three stations under single-motor drive. Testing shows that the single-station repeatability accuracy of this embodiment is ≤4.5 arcseconds, and the maximum synchronization error between stations is ≤2.5 arcseconds, meeting the high-speed drilling and tapping batch processing requirements for 3C product casings.

[0052] Compared to the solution of three independent rotary tables in parallel, this embodiment improves the structural compactness by 45%, reduces manufacturing costs by 38%, and requires only one drive and lubrication system, reducing maintenance workload by 70%, making it very suitable for multi-spindle batch processing scenarios in large-scale production lines.

[0053] Example 3 This embodiment is a horizontal dual-station coaxial tandem cam exchange turntable (APC200 type) adapted to a horizontal dual-exchange machining center. Based on the core structure of Embodiment 1, the output worktable 4 is integrated with the exchange station, which is applicable to the application scenarios of APC horizontal cam exchange tables and further expands the application boundaries.

[0054] In this embodiment, the entire structure is horizontally mounted. The base 1 is a horizontal box structure, the main input shaft 22 is horizontally arranged, and two sets of cam roller drive units 3 are connected in series along the axial direction, corresponding to the machining station and the preparation station, respectively. The two output worktables 4 are the machining station worktable and the waiting station worktable, respectively. The workpieces are transferred between the stations through a cam exchange mechanism. The exchange mechanism is also synchronously driven by the main input shaft 22 to ensure the timing synchronization of indexing and exchange actions.

[0055] This embodiment retains all core structures such as common cavity lubrication, unified detection and compensation, and disc spring brake, ultimately achieving a processing station repeatability accuracy of ≤4 arcseconds, a station exchange repeatability positioning accuracy of ≤0.01mm, and an exchange time of ≤2s. Compared with the traditional independently driven dual exchange station solution, the exchange synchronization is improved by 50%, and the structural integration is higher.

[0056] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-station cam roller CNC rotary table with coaxial series synchronous drive, characterized in that, It includes a base, an input drive assembly, at least two sets of cam roller drive units arranged coaxially in series, an output worktable that corresponds to each of the cam roller drive units, and an integrated common cavity lubrication assembly; The input drive assembly includes a servo motor and a main input shaft that runs coaxially through all cam roller drive units, with the servo motor being drive-connected to one end of the main input shaft; Each of the cam roller transmission units includes an arc-shaped cam fixedly sleeved on the main input shaft and a needle roller bearing output assembly that meshes with the arc-shaped cam without clearance. The output end of the needle roller bearing output assembly is coaxially fixedly connected to the corresponding output worktable. The arc-shaped cams of all cam roller drive units are arranged sequentially along the main input shaft axis and their indexing curves are completely in phase. The integrated common cavity lubrication assembly is located inside the base and is connected to the meshing area of ​​all cam roller drive units.

2. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 1, characterized in that, The needle roller bearing output assembly includes an output shaft, several needle roller bearing units evenly arranged circumferentially along the output shaft, and an output end flange. The needle roller bearing units are fixed to the end face of the output shaft by pins, and the rolling surfaces of all the needle roller bearings mesh with the annular contour surface of the arc cam. The output end flange is coaxially fixed to the output shaft, and the output worktable is locked to the output end flange by bolts.

3. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 2, characterized in that, The needle roller bearing unit adopts a forged blank integral needle roller structure, the concentricity of the grinding of the roller and the sleeve is ≤0.5μm, and the overall radial runout of the assembled needle roller bearing is ≤1μm; the number of needle roller bearing units in each set of needle roller bearing output components is 8~12 sets, which are distributed at equal angles along the circumference of the output shaft.

4. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 1, characterized in that, The integrated common cavity lubrication assembly includes an oil storage cavity disposed at the bottom of the base, an oil supply path connecting the meshing areas of all cam roller drive units, an oil return path, and a circulating filter unit; the oil supply path is provided with a throttling nozzle at the meshing inlet of each set of arc-shaped cams, the oil return path converges into the oil storage cavity, and the circulating filter unit is disposed between the oil storage cavity and the oil supply path.

5. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 1, characterized in that, A phase adjustment sleeve is provided between two adjacent arc-shaped cams on the main input shaft. The phase adjustment sleeve cooperates with the main input shaft through a flat key to finely adjust the circumferential phase difference between adjacent arc-shaped cams, ensuring that the synchronization error of the indexing start position of all output worktables is ≤2 arcseconds.

6. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 1, characterized in that, Each output workbench is equipped with a built-in disc spring brake assembly, which includes a brake seat fixed in the base, a brake disc sleeved on the output shaft, an axially arranged disc spring assembly, and a hydraulic release unit. Under normal conditions, the disc spring assembly pushes the brake seat to press the brake disc to achieve locking. When the hydraulic release unit is energized, it pushes the disc spring assembly to compress and release the locking.

7. The multi-station cam roller CNC rotary table with coaxial series synchronous drive according to claim 1, characterized in that, Each output workbench is equipped with an absolute angle detection unit at the end of its output shaft. The signals from all angle detection units are connected to the same control module. The control module uses a servo motor to perform overall accuracy compensation on the main input shaft based on multi-station angle feedback data. After compensation, the single-station repeatability positioning accuracy is ≤4 arcseconds, and the synchronization error between stations is ≤2 arcseconds.

8. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 1, characterized in that, The base is an integrally cast box structure, and all cam roller drive units are installed in the same box cavity. The top of the base is provided with a mounting flange surface corresponding to each output worktable, and the center distance between adjacent output worktables is consistent with the center distance of the multi-spindle of the matching machine tool.

9. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 2, characterized in that, The output shaft is supported in the base by a pair of tapered roller bearings mounted back to back, and the preload of the bearings is adjusted by the end locking nut. A labyrinth seal structure is provided between the output shaft and the base, which, together with the common cavity lubrication assembly, forms a positive pressure seal to prevent cutting fluid and dust from entering the interior.

10. The coaxial series synchronously driven multi-station cam roller CNC rotary table according to claim 1, characterized in that, The number of cam roller drive units is 2 to 4, corresponding to 2 to 4 output worktables; all output worktables have the same diameter, load-bearing capacity and indexing accuracy level, which is suitable for synchronous batch processing scenarios of multi-spindle machining centers.

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