Internal tooth grinding machine for numerical control formed gear ring and using method of internal tooth grinding machine

Abstract

The invention discloses a numerical control forming gear ring inner tooth grinding machine and a using method thereof.The numerical control forming gear ring inner tooth grinding machine comprises a lathe bed assembly, a numerical control rotary table assembly, a grinding wheel spindle assembly and a workpiece clamping assembly, the lathe bed assembly adopts a mineral casting base, the damping coefficient is larger than 10%, and a linear guide rail is installed on the lathe bed assembly; s3, grinding feeding and indexing; S4, grinding stage control; S5, track correction; S6, grinding wheel wear compensation; through a mineral casting base of the lathe bed assembly, an angle encoder of the numerical control rotary table assembly and a CBN material formed grinding wheel of the grinding wheel spindle assembly, the effect of improving the machining precision is achieved; through the steps S2, S4 and S5, the effect of optimizing the machining quality is achieved, the tooth profile error and the surface roughness are effectively controlled, and the machining quality of the inner gear ring is improved; and through S1, S3 and S6, the effect of improving the machining stability and reliability is achieved, and the machining stability and reliability of equipment are improved.

Description

Technical Field

[0001] This invention relates to the field of precision gear machining technology, and in particular to a CNC gear forming internal gear grinding machine and its usage method. Background Technology

[0002] As a crucial component in mechanical transmission systems, gears' machining precision and quality directly affect the performance, stability, and service life of mechanical equipment. Precision gear machining is of great significance for improving mechanical transmission efficiency, reducing energy consumption, and minimizing vibration and noise. It is widely used in many high-end manufacturing fields such as automobiles, aerospace, shipbuilding, and precision machine tools. Internal gear rings, as a special type of gear, play an indispensable role in various mechanical transmission devices. For example, in planetary gear reducers, internal gear rings cooperate with planetary gears to achieve power transmission and distribution.

[0003] In terms of improving machining accuracy, the special structure of the internal gear ring results in a narrow machining space. Conventional grinding wheels often interfere with the tooth surface during operation, severely hindering the improvement of tooth profile accuracy. Although traditional electrochemical machining can process hard materials, its machining efficiency is extremely low, and the machined tooth surface is prone to micro-cracks. This not only reduces the tooth surface quality but also significantly shortens the gear's service life, making it difficult to meet high-precision machining requirements. While honing can achieve a surface quality of Ra0.6μm, its tooth profile accuracy control can only reach ±0.015mm, which cannot meet the requirements of high precision machining. Precision transmission has stringent standards for tooth profile error and cannot correct heat treatment deformation, limiting its application in the field of high-precision internal gear ring machining. Traditional internal gear grinding machines use radial feed grinding with shaped grinding wheels, which can achieve an accuracy of ±0.008mm, but the grinding wheel needs to be dressed too frequently, once every 20 parts processed. This not only increases the processing cost and time cost, but also makes it difficult to ensure the consistency of grinding wheel after dressing, resulting in reduced stability of tooth profile accuracy and surface roughness. Therefore, it is necessary to design a CNC shaped gear ring internal gear grinding machine to solve the above-mentioned problems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art by proposing a CNC forming gear internal gear grinding machine and its usage method to solve the problems in the above-mentioned technical solutions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a CNC gear grinding machine for forming gear rings, comprising a bed assembly, a CNC rotary table assembly, a grinding wheel spindle assembly, and a workpiece clamping assembly. The bed assembly uses a mineral casting base with a damping coefficient >10%. A linear guide rail is mounted on the bed assembly. The mineral casting base provides a stable and robust support foundation for the entire gear grinding machine. The linear guide rail provides high-precision, low-friction linear motion guidance for the grinding wheel spindle assembly mounted thereon. The CNC rotary table assembly includes a DD motor, an angle encoder, and a harmonic reducer. The DD motor has a torque ≥200 Nm, and the angle encoder has a resolution of 0.001°. The DD motor and the angle encoder are connected to the workpiece clamping assembly through the harmonic reducer. The DD motor provides sufficient torque to the workpiece clamping assembly, the angle encoder accurately measures the rotation angle of the CNC rotary table, and the harmonic reducer achieves a large transmission ratio reduction while transmitting power from the DD motor to improve torque output.

[0006] The grinding wheel spindle assembly includes an electric spindle and a forming grinding wheel. The electric spindle rotates at 30,000 rpm. The forming grinding wheel is made of CBN material with a grit size of 120#, and the axis of the forming grinding wheel is inclined at a 15° angle to the axis of the workpiece. The workpiece clamping assembly uses a hydraulic expansion mandrel and, in conjunction with an end face positioning pin, achieves a workpiece coaxiality of ≤0.005mm. The expansion amount of the hydraulic expansion mandrel is 0.02mm.

[0007] Furthermore, it also includes a grinding wheel dressing mechanism, which integrates a diamond roller with a particle size of 50μm, and the dressing cycle of the grinding wheel dressing mechanism is extended to 50 pieces / time.

[0008] Furthermore, it also includes a laser tool setter with an accuracy of 0.001mm, which is used to automatically compensate for the wear of the grinding wheel.

[0009] A method for using a CNC gear ring internal gear grinding machine, applicable to a CNC gear ring internal gear grinding machine, includes the following steps: S1. Workpiece clamping: Install the workpiece to be processed onto the workpiece clamping assembly. When clamping the hydraulic expansion mandrel, start the hydraulic system to expand the hydraulic expansion mandrel to 0.02mm and fit it tightly against the inner hole of the workpiece. Then, use the end face positioning pin for precise axial positioning. At the same time, use a high-precision coaxiality testing instrument to measure and control the coaxiality of the internal gear ring workpiece within the accuracy range of ≤0.005mm. S2. Grinding wheel trajectory calculation: By accurately inputting various tooth profile parameters of the internal gear ring into the CNC system, the CNC system automatically generates a precise forming grinding wheel motion trajectory based on the built-in complex algorithm and in combination with the input parameters. During the generation of the cloud trajectory, the system incorporates a tooth profile modification amount of 0.01-0.03mm into the trajectory according to preset process requirements; Simultaneously, the generated trajectory data is displayed graphically on the CNC system screen; S3. Grinding feed and indexing: Start the grinding wheel spindle assembly. The electric spindle drives the forming grinding wheel to accelerate to the rated speed of 30,000 rpm. After the forming grinding wheel runs stably, the forming grinding wheel starts to feed along the involute envelope path at a constant speed of 0.5 mm / s. Meanwhile, the CNC rotary table assembly performs indexing motion based on the number of teeth information, with an interval angle of 360° per tooth / number of teeth. During the indexing process, the angle encoder monitors the rotation angle of the rotary table in real time. S4. Grinding Stage Control: The grinding process is divided into two stages: rough grinding and fine grinding. During the rough grinding stage, the grinding depth is 0.05mm. The feed speed of the grinding wheel and the grinding power can be adjusted appropriately according to the characteristics of the workpiece material. At the same time, the grinding power is monitored in real time through an online monitoring system. When abnormal fluctuations occur in the power, the grinding parameters are adjusted in time. During the fine grinding stage, the grinding depth is adjusted to 0.01mm to perform fine machining on the tooth surface. At the same time, the feed speed of the forming grinding wheel is reduced to 0.3mm / s, and a micro-lubrication system is used to spray an appropriate amount of lubricant into the grinding area. S5. Trajectory Correction: In step S4, the laser displacement sensor and gear measurement software, combined with the measurement system, continuously monitor the processing status in real time. The collected data is transmitted to the CNC system in real time. The error analysis and compensation algorithm built into the CNC system processes the feedback data, calculates the correction amount of the forming grinding wheel's motion trajectory, and automatically adjusts the feed direction, speed and indexing angle of the forming grinding wheel and the rotary table according to the correction amount. S6. Grinding wheel wear compensation: During the processing, the laser tool setter automatically detects the forming grinding wheel every 55 minutes. The laser tool setter emits a laser beam and obtains the wear data of the grinding wheel by measuring the reflected light of the laser beam on the surface of the grinding wheel. When the wear of the grinding wheel exceeds 0.005mm, the laser tool setter transmits the wear data to the CNC system. The CNC system automatically adjusts the position of the forming grinding wheel according to the wear amount to compensate for the wear and maintain the processing accuracy of the grinding wheel. S7. Inspection: After the machining process is completed, the machined internal gear ring is inspected to ensure the quality of the workpiece. If the quality of the workpiece does not meet the requirements, it is reworked or scrapped.

[0010] Furthermore, in the S3 grinding feed and indexing step, the CBN forming grinding wheel with a grit size of 120# can be replaced with a corundum forming grinding wheel. At the same time, the feed speed is adjusted to 0.4 mm / s, and every 5 workpieces are processed, the grinding wheel wear detection tool is used to detect the wear shape, wear amount and surface roughness of the grinding wheel. If the wear of a corundum forming grinding wheel exceeds 0.02mm, or if obvious peeling or scratches appear on the surface, the grinding wheel must be replaced in time.

[0011] Furthermore, in the S1 workpiece clamping step, when a mechanical three-jaw chuck is used to replace the hydraulic expansion mandrel, the workpiece position is initially adjusted using a centering tool, and then precise measurement and fine-tuning are performed using a dial indicator to ensure that the coaxiality of the workpiece is ≤0.01mm. After clamping, the coaxiality is checked again using a coaxiality testing instrument to ensure clamping accuracy.

[0012] Furthermore, in the S6 grinding wheel wear compensation step, when the laser tool setter detects that the grinding wheel wear exceeds 0.005mm, the CNC system, while performing grinding wheel position compensation, also reduces the grinding wheel feed speed to 0.05mm / s according to the grinding wheel wear condition. At the same time, the CNC system records the wear amount, compensation time, and processing parameter data after each grinding wheel wear compensation.

[0013] In summary, the present invention provides a CNC forming gear ring internal gear grinding machine, which has the following beneficial effects: 1. By utilizing the mineral casting base of the bed assembly, the angle encoder of the CNC rotary table assembly, and the CBN shaped grinding wheel of the grinding wheel spindle assembly, the machining accuracy is improved. The mineral casting base effectively absorbs vibration, providing a stable foundation for machining and reducing the impact of vibration on machining accuracy. The angle encoder accurately measures the rotation angle of the CNC rotary table, ensuring precise indexing and controlling tooth pitch error. The CBN shaped grinding wheel has excellent grinding performance, enabling efficient and precise grinding of the internal gear ring, reducing tooth profile error, improving the overall machining accuracy of the internal gear ring, controlling tooth profile error within a smaller range, and improving the accuracy and smoothness of gear transmission.

[0014] 2. Through the S2 grinding wheel trajectory calculation, S4 grinding stage control, and S5 trajectory correction steps, the machining quality is optimized, effectively controlling tooth profile error and surface roughness, improving the machining quality of the internal gear ring, enhancing gear transmission performance, and extending gear service life. In step S2, the CNC system generates a precise grinding wheel motion trajectory based on input parameters and incorporates tooth profile modification, laying the foundation for precision machining. Step S4 divides the grinding process into rough grinding and fine grinding. Rough grinding quickly removes excess material, while fine grinding ensures tooth surface accuracy and surface quality, and parameters can be adjusted according to the workpiece material. Step S5 uses a measurement system to monitor and correct the grinding wheel trajectory in real time, promptly compensating for machining errors.

[0015] 3. By employing the S1 workpiece clamping, S3 grinding feed and indexing, and S6 grinding wheel wear compensation steps, the stability and reliability of machining are improved, unstable factors during machining are reduced, the stability and reliability of equipment machining are enhanced, the scrap rate is reduced, and smooth production is ensured. In step S1, the hydraulic expansion mandrel, in conjunction with the end face locating pin, ensures that the coaxiality of the workpiece is ≤0.005mm, keeping the workpiece stable during machining. In step S3, the grinding wheel is fed stably, the rotary table is precisely indexed, and the angle encoder monitors in real time, ensuring the accuracy and stability of the machining process. In step S6, the laser tool setter periodically detects the wear of the grinding wheel, and the CNC system automatically compensates, ensuring that the grinding wheel is always in a good grinding condition. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process architecture of a CNC forming gear ring internal gear grinding machine and its usage method according to the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example: This invention provides a technical solution: a CNC gear grinding machine for forming internal gear rings, comprising a bed assembly, a CNC rotary table assembly, a grinding wheel spindle assembly, and a workpiece clamping assembly. The bed assembly uses a mineral casting base with a damping coefficient >10%. Due to its high damping characteristics, the mineral casting base effectively absorbs the vibration generated during high-speed operation and grinding, avoiding the impact of vibration on machining accuracy, ensuring stable operation, thereby improving machining accuracy and reducing scrap rate. A linear guide rail is installed on the bed assembly, ensuring accurate positioning of the grinding wheel spindle assembly during movement, enabling the grinding wheel to accurately grind the internal gear ring according to a preset trajectory, thus improving machining accuracy. The mineral casting base provides a stable and robust support foundation for the entire gear grinding machine, while the linear guide rail provides high-precision, low-friction linear motion guidance for the grinding wheel spindle assembly mounted on it. The CNC rotary table assembly includes a DD motor, an angle encoder, and a harmonic reducer. The DD motor has a torque ≥200Nm, and the angle encoder has a resolution of 0.001°. The high-torque DD motor can stably drive the workpiece clamping assembly and the workpiece to rotate, ensuring smooth rotation even when machining large-sized, heavy-load internal gear rings, avoiding jamming, shaking, and other phenomena. The DD motor and angle encoder are connected to the workpiece clamping assembly through the harmonic reducer. The DD motor provides sufficient torque to the workpiece clamping assembly, the angle encoder accurately measures the rotation angle of the CNC rotary table, and the harmonic reducer achieves a large transmission ratio reduction while transmitting power from the DD motor, thereby improving torque output.

[0019] The grinding wheel spindle assembly includes an electric spindle and a forming grinding wheel. The electric spindle rotates at 30,000 rpm, and the forming grinding wheel is made of CBN material with a grit size of 120#. The axis of the forming grinding wheel is at a 15° angle to the axis of the workpiece, which can significantly improve grinding efficiency and complete the machining of the internal gear ring in a short time, thereby improving production efficiency. At the same time, the CBN grinding wheel has strong grinding force under high-speed rotation, which can effectively machine the internal gear ring of high-hardness materials, thus expanding the processing range of the equipment. The workpiece clamping assembly uses a hydraulic expansion mandrel, and with the end face positioning pin, the coaxiality of the workpiece is ≤0.005mm. The expansion amount of the hydraulic expansion mandrel is 0.02mm, which ensures that the center of the workpiece coincides with the machining center of the machine tool during the grinding process, effectively reducing machining eccentricity and improving the roundness and tooth profile accuracy of the internal gear ring.

[0020] It also includes a grinding wheel dressing mechanism, which integrates diamond rollers with a particle size of 50μm. The dressing cycle of the grinding wheel dressing mechanism is extended to 50 pieces / time. Compared with the traditional frequent dressing method, it greatly reduces the number of grinding wheel dressings, saves dressing time, and improves the processing efficiency of the equipment. The extended dressing cycle means that the grinding wheel maintains good grinding performance for a longer period of time, making the quality of the machined internal gear ring more stable, with better tooth profile accuracy and surface roughness consistency. It reduces the processing error caused by grinding wheel wear, reduces the scrap rate, and also reduces the wear cost of grinding wheels.

[0021] It also includes a laser tool setter with an accuracy of 0.001mm. The laser tool setter is used to automatically compensate for the wear of the grinding wheel, ensuring that the grinding wheel maintains the optimal cutting position and grinding accuracy throughout the entire machining process. The automatic compensation function avoids the decrease in machining accuracy caused by grinding wheel wear, ensuring that the tooth profile error and tooth pitch error of the machined internal gear ring are always controlled within the specified range, thus improving product quality. At the same time, it reduces the workload of manual measurement and adjustment of the grinding wheel, lowers labor costs, improves the degree of production automation, and makes the production process more efficient and stable.

[0022] Please see Figure 1As shown, a method for using a CNC gear ring internal gear grinding machine is applicable to the aforementioned CNC gear ring internal gear grinding machine, and includes the following steps: S1. Workpiece Clamping: The workpiece to be processed is installed on the workpiece clamping assembly. During hydraulic expansion mandrel clamping, the hydraulic system is activated to expand the hydraulic expansion mandrel to 0.02mm and tightly fit it against the inner hole of the workpiece. Then, the end face locating pin is used for precise axial positioning. At the same time, the coaxiality of the internal gear ring workpiece is controlled within the accuracy range of ≤0.005mm by measuring with a high-precision coaxiality testing instrument. The high-precision clamping method controls the coaxiality of the workpiece within a very small range, ensuring that the workpiece is in an ideal position during grinding, avoiding tooth profile deviation and uneven tooth pitch caused by clamping errors, improving the machining accuracy of the internal gear ring, and reducing the scrap rate. The precise axial positioning and tight-fitting clamping method can ensure that the workpiece remains stable under high-speed rotation and grinding force, improving the safety of the machining process, while reducing wear on the grinding wheel caused by workpiece shaking and extending the service life of the grinding wheel. S2. Grinding Wheel Trajectory Calculation: By accurately inputting various tooth profile parameters of the internal gear ring into the CNC system, the CNC system automatically generates a precise grinding wheel motion trajectory based on its built-in complex algorithm and the input parameters. This reduces the workload of manual calculation and programming, improves production efficiency, and avoids errors that may occur during manual calculation, ensuring the accuracy of the grinding wheel motion trajectory. The precise trajectory generation allows the grinding wheel to grind according to the design requirements of the internal gear ring, effectively controlling tooth profile errors, improving the machining accuracy of the internal gear ring, and ensuring the smoothness and accuracy of gear transmission. During the generation of the cloud trajectory, the system incorporates a tooth profile modification amount of 0.01-0.03mm into the trajectory according to the preset process requirements, thereby reducing the load concentration phenomenon in the gear transmission process, reducing transmission vibration and noise, and improving the smoothness and reliability of gear transmission. Meanwhile, the generated trajectory data is displayed graphically on the CNC system screen. The graphical display of trajectory data makes it easy for operators to intuitively view the grinding wheel's movement trajectory, promptly detect any abnormalities in the trajectory, and facilitate adjustments and optimizations. S3. Grinding Feed and Indexing: Start the grinding wheel spindle assembly. The electric spindle drives the forming grinding wheel to accelerate to its rated speed of 30,000 rpm. After the forming grinding wheel stabilizes, it begins to feed along the involute envelope path at a constant speed of 0.5 mm / s. The stable feed speed ensures the uniformity of the grinding process, making the grinding amount on the tooth surface of the internal gear ring consistent, improving the surface quality and machining accuracy of the tooth surface. The involute envelope path feeding method ensures that the grinding wheel can accurately grind the involute tooth profile of the internal gear ring, effectively controlling tooth profile error and improving the transmission accuracy of the gear. Meanwhile, the CNC rotary table assembly performs indexing motion based on the number of teeth information, with an interval angle of 360° per tooth. During the indexing process, the angle encoder monitors the rotation angle of the rotary table in real time. The precise indexing motion and angle monitoring ensure the accurate machining position of each tooth, effectively control the tooth pitch error, improve the transmission accuracy of the internal gear ring, reduce the impact and vibration during gear meshing, and reduce transmission noise. S4. Grinding Stage Control: The grinding process is divided into two stages: rough grinding and fine grinding. The rough grinding stage quickly removes most of the machining allowance and improves machining efficiency; the fine grinding stage performs fine machining on the tooth surface to ensure the accuracy and surface quality of the tooth surface. During the rough grinding stage, the grinding depth is 0.05mm. The feed speed of the grinding wheel and the grinding power can be adjusted appropriately according to the characteristics of the workpiece material. At the same time, the grinding power is monitored in real time through an online monitoring system. When abnormal fluctuations occur in the power, the grinding parameters are adjusted in time. Adjusting the parameters according to the characteristics of the workpiece material can give full play to the grinding performance of the grinding wheel, improve grinding efficiency, and avoid excessive wear of the grinding wheel or workpiece burning caused by improper parameters. Online monitoring of grinding power and timely adjustment of parameters ensure the stability of the grinding process, improve processing quality, reduce scrap rate, and reduce production costs. During the fine grinding stage, the grinding depth is adjusted to 0.01mm to perform fine machining on the tooth surface. At the same time, the feed speed of the forming grinding wheel is reduced to 0.3mm / s. Meanwhile, a micro-lubrication system is used to spray an appropriate amount of lubricant into the grinding area. The reduced grinding depth and feed speed help improve the machining accuracy and surface quality of the tooth surface, making the tooth surface of the internal gear ring smoother, reducing tooth surface roughness, and improving the smoothness of gear transmission. S5. Track Correction: In step S4, the laser displacement sensor and gear measurement software, combined with the measurement system, continuously monitor the machining process in real time, providing accurate data support for track correction, ensuring that the grinding wheel always grinds along the ideal trajectory, effectively controlling tooth profile error and tooth pitch error, and improving machining accuracy. The collected data is transmitted to the CNC system in real time. The error analysis and compensation algorithm built into the CNC system processes the feedback data, calculates the correction amount of the forming grinding wheel's motion trajectory, and automatically adjusts the feed direction, speed of the forming grinding wheel and the indexing angle of the turntable according to the correction amount. This achieves real-time compensation for machining errors, ensures the stability of machining accuracy, and improves the automation level and machining reliability of the equipment. S6. Grinding Wheel Wear Compensation: During the machining process, the laser tool setter automatically detects the forming grinding wheel every 55 minutes. The laser tool setter emits a laser beam and obtains the wear data of the grinding wheel by measuring the reflected light of the laser beam on the surface of the grinding wheel. When the wear of the grinding wheel exceeds 0.005mm, the laser tool setter transmits the wear data to the CNC system. The CNC system automatically adjusts the position of the forming grinding wheel according to the wear amount to compensate for the wear and maintain the machining accuracy of the grinding wheel. The periodic detection and automatic compensation functions ensure that the grinding wheel maintains good grinding performance throughout the entire machining process, ensuring that the machining accuracy is not affected by the wear of the grinding wheel, improving the machining quality of the internal gear ring, and reducing the scrap rate. S7. Inspection: After the machining process is completed, the machined internal gear ring is inspected to ensure the quality of the workpiece. If the quality of the workpiece does not meet the requirements, it is reworked or scrapped.

[0023] In the S3 grinding feed and indexing steps, the 120# CBN forming wheel can be replaced with a corundum forming wheel. The feed speed is adjusted to 0.4 mm / s. Every five workpieces processed, a grinding wheel wear detection tool is used to inspect the wear shape, wear amount, and surface roughness of the grinding wheel. This provides alternative grinding wheel materials, increasing the equipment's adaptability. Appropriate grinding wheels can be selected based on different processing requirements and cost budgets. Regularly inspecting grinding wheel wear allows for timely detection of abnormal wear and proactive measures. If the wear of the corundum forming grinding wheel exceeds 0.02mm, or if obvious peeling or scratches appear on the surface, the grinding wheel must be replaced in time. Timely replacement of grinding wheels with excessive wear can ensure that the machining accuracy is not affected, guarantee the machining quality of the internal gear ring, avoid workpiece scrapping and equipment failure caused by continued use of damaged grinding wheels, reduce production costs, and improve production efficiency.

[0024] In the S1 workpiece clamping step, when a mechanical three-jaw chuck is used instead of a hydraulic expansion mandrel, the workpiece position is initially adjusted using a centering tool, and then precise measurement and fine-tuning are performed using a dial indicator to ensure that the coaxiality of the workpiece is ≤0.01mm. After clamping, the coaxiality is checked again using a coaxiality testing instrument to ensure clamping accuracy. This increases the flexibility of the clamping method, allowing for the selection of appropriate clamping tools according to actual conditions. Precise measurement and verification ensure clamping accuracy, reduce machining errors caused by improper clamping, and improve the machining accuracy of the internal gear ring.

[0025] In the S6 grinding wheel wear compensation step, when the laser tool setter detects that the grinding wheel wear exceeds 0.005mm, the CNC system, while performing grinding wheel position compensation, also reduces the grinding wheel feed rate to 0.05mm / s based on the grinding wheel wear condition. Simultaneously, the CNC system records the wear amount, compensation time, and post-compensation machining parameters for each grinding wheel wear compensation. Reducing the feed rate further ensures machining accuracy after grinding wheel wear, reducing machining errors caused by grinding wheel wear. Recording compensation data helps analyze the grinding wheel wear pattern, providing data support for optimizing machining processes and adjusting grinding wheel replacement cycles.

[0026] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A CNC gear grinding machine for forming internal gear rings, comprising a bed assembly, a CNC rotary table assembly, a grinding wheel spindle assembly, and a workpiece clamping assembly, characterized in that: The bed assembly uses a mineral casting base with a damping coefficient >10%. A linear guide is installed on the bed assembly. The mineral casting base provides a stable and robust support foundation for the entire gear grinding machine. The linear guide provides high-precision, low-friction linear motion guidance for the grinding wheel spindle assembly mounted on it. The CNC rotary table assembly includes a DD motor, an angle encoder, and a harmonic reducer. The DD motor has a torque ≥200 Nm, and the angle encoder has a resolution of 0.001°. The DD motor and the angle encoder are connected to the workpiece clamping assembly through the harmonic reducer. The DD motor provides sufficient torque to the workpiece clamping assembly, the angle encoder accurately measures the rotation angle of the CNC rotary table, and the harmonic reducer achieves a large transmission ratio reduction while transmitting power from the DD motor to improve torque output.

2. The grinding wheel spindle assembly includes an electric spindle and a forming grinding wheel. The electric spindle rotates at 30,000 rpm. The forming grinding wheel is made of CBN material with a grit size of 120#, and the axis of the forming grinding wheel is inclined at a 15° angle to the axis of the workpiece. The workpiece clamping assembly uses a hydraulic expansion mandrel and, in conjunction with an end face positioning pin, achieves a workpiece coaxiality of ≤0.005mm. The expansion amount of the hydraulic expansion mandrel is 0.02mm.

3. The CNC forming gear ring internal gear grinding machine according to claim 1, characterized in that: It also includes a grinding wheel dressing mechanism, which integrates a diamond roller with a particle size of 50μm, and the dressing cycle of the grinding wheel dressing mechanism is extended to 50 pieces / time.

4. The CNC forming gear ring internal gear grinding machine according to claim 1, characterized in that: It also includes a laser tool setter with an accuracy of 0.001 mm, which is used to automatically compensate for the wear of the grinding wheel.

5. A method of using a CNC forming gear ring internal gear grinding machine, applicable to the CNC forming gear ring internal gear grinding machine as described in any one of claims 1-3, characterized in that: The following usage steps are included: S1. Workpiece clamping: Install the workpiece to be processed onto the workpiece clamping assembly. When clamping the hydraulic expansion mandrel, start the hydraulic system to expand the hydraulic expansion mandrel to 0.02mm and fit it tightly against the inner hole of the workpiece. Then, use the end face positioning pin for precise axial positioning. At the same time, use a high-precision coaxiality testing instrument to measure and control the coaxiality of the internal gear ring workpiece within the accuracy range of ≤0.005mm. S2. Grinding wheel trajectory calculation: By accurately inputting various tooth profile parameters of the internal gear ring into the CNC system, the CNC system automatically generates a precise forming grinding wheel motion trajectory based on the built-in complex algorithm and in combination with the input parameters. During the generation of the cloud trajectory, the system incorporates a tooth profile modification amount of 0.01-0.03mm into the trajectory according to preset process requirements; Simultaneously, the generated trajectory data is displayed graphically on the CNC system screen; S3. Grinding feed and indexing: Start the grinding wheel spindle assembly. The electric spindle drives the forming grinding wheel to accelerate to the rated speed of 30,000 rpm. After the forming grinding wheel runs stably, the forming grinding wheel starts to feed along the involute envelope path at a constant speed of 0.5 mm / s. Meanwhile, the CNC rotary table assembly performs indexing motion based on the number of teeth information, with an interval angle of 360° per tooth / number of teeth. During the indexing process, the angle encoder monitors the rotation angle of the rotary table in real time. S4. Grinding Stage Control: The grinding process is divided into two stages: rough grinding and fine grinding. During the rough grinding stage, the grinding depth is 0.05mm. The feed speed of the grinding wheel and the grinding power can be adjusted appropriately according to the characteristics of the workpiece material. At the same time, the grinding power is monitored in real time through an online monitoring system. When abnormal fluctuations occur in the power, the grinding parameters are adjusted in time. During the fine grinding stage, the grinding depth is adjusted to 0.01mm to perform fine machining on the tooth surface. At the same time, the feed speed of the forming grinding wheel is reduced to 0.3mm / s, and a micro-lubrication system is used to spray an appropriate amount of lubricant into the grinding area. S5. Trajectory Correction: In step S4, the laser displacement sensor and gear measurement software, combined with the measurement system, continuously monitor the processing status in real time. The collected data is transmitted to the CNC system in real time. The error analysis and compensation algorithm built into the CNC system processes the feedback data, calculates the correction amount of the forming grinding wheel's motion trajectory, and automatically adjusts the feed direction, speed and indexing angle of the forming grinding wheel and the rotary table according to the correction amount. S6. Grinding wheel wear compensation: During the processing, the laser tool setter automatically detects the forming grinding wheel every 55 minutes. The laser tool setter emits a laser beam and obtains the wear data of the grinding wheel by measuring the reflected light of the laser beam on the surface of the grinding wheel. When the wear of the grinding wheel exceeds 0.005mm, the laser tool setter transmits the wear data to the CNC system. The CNC system automatically adjusts the position of the forming grinding wheel according to the wear amount to compensate for the wear and maintain the processing accuracy of the grinding wheel. S7. Inspection: After the machining process is completed, the machined internal gear ring is inspected to ensure the quality of the workpiece. If the quality of the workpiece does not meet the requirements, it is reworked or scrapped.

6. The method of using a CNC forming gear ring internal gear grinding machine according to claim 4, characterized in that: In the S3 grinding feed and indexing step, the CBN forming grinding wheel with a grit size of 120# can be replaced with a corundum forming grinding wheel. At the same time, the feed speed is adjusted to 0.4 mm / s, and every 5 workpieces are processed, the grinding wheel wear detection tool is used to detect the wear shape, wear amount and surface roughness of the grinding wheel. If the wear of a corundum forming grinding wheel exceeds 0.02mm, or if obvious peeling or scratches appear on the surface, the grinding wheel must be replaced in time.

7. The method of using a CNC forming gear ring internal gear grinding machine according to claim 5, characterized in that: In the S1 workpiece clamping step, when a mechanical three-jaw chuck is used to replace the hydraulic expansion mandrel, the workpiece position is initially adjusted using a centering tool, and then precise measurement and fine-tuning are performed using a dial indicator to ensure that the coaxiality of the workpiece is ≤0.01mm. After clamping, the coaxiality is checked again using a coaxiality testing instrument to ensure clamping accuracy.

8. The method of using a CNC forming gear ring internal gear grinding machine according to claim 6, characterized in that: In the S6 grinding wheel wear compensation step, when the laser tool setter detects that the grinding wheel wear exceeds 0.005mm, the CNC system, while performing grinding wheel position compensation, also reduces the grinding wheel feed speed to 0.05mm / s according to the grinding wheel wear condition. At the same time, the CNC system records the wear amount, compensation time, and machining parameter data after each grinding wheel wear compensation.

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