Gear Flank Modification Using a Variable Lead Grinding Worm Method on a Computer Numerical Control Gear Grinding Machine

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Zhang-Hua Fong ◽  
Gwan-Hon Chen
Keyword(s):  
Rotation Angle ◽  
Helical Gear ◽  
Numerical Control ◽  
Helical Gears ◽  
Numerical Examples ◽  
Gear Grinding ◽  
Helical Angle ◽  
Grinding Machines ◽  
Grinding Machine ◽  
Tooth Flank

Tooth crowning of a ground helical gear is usually done by adjusting the radial feed with respect to the axial feed of the grinding worm on the modern CNC gear grinding machine. However, when the amount of crowning and the helical angle of the gear are large, this method always results in a twisted tooth flank. Hence, in this paper, we propose a tooth flank crowning method for helical gears, which uses a diagonal (combined tangential and axial) feed on a grinding machine with a variable lead grinding worm (VLGW) obtained by adjusting the axial feed of the dressing disk with respect to the rotation angle of the grinding worm. Since all the required corrective motions for the proposed VLGW method are existing CNC controlled axes on modern gear grinding machines, it can easily be implemented without extra cost to modify the grinder hardware. Three numerical examples are presented to show the validation of the proposed method and its ability to reduce tooth flank twist even in the case of a large helical angle, with a particularly significant reduction on a crowned helical gear.

Generation of the Anti-Twist Crowned Helical Gear by Modifying the Gear Rotation Angle in the Hobbing Process

2017 ◽  
Vol 749 ◽  
pp. 161-170
Author(s):  
Ruei Hung Hsu ◽  
Yu Ren Wu ◽  
Shih Sheng Chen
Keyword(s):  
Rotation Angle ◽  
Gear Tooth ◽  
Helical Gear ◽  
Gear Hobbing ◽  
Tooth Flank ◽  
Center Distance

In the gear-hobbing process, the work gear tooth flank is usually longitudinally crowned by varying the center distance between the hob and the work gear. Without crossed angle compensation, however, this center distance variation produces a twisted tooth flank on the work gear. This paper therefore proposes a methodology to reduce this tooth flank twist and achieve anti-twist in longitudinal crowning by modifying the gear rotation angle in the hobbing process which is practiced using a CNC hobbing machine with three synchronous axes.

scholarly journals Generation of a double-crowned involute helical gear with twist-free tooth flanks by a CNC hobbing machine with three synchronous axes

2017 ◽  
Vol 39 (2) ◽  
pp. 97-108
Author(s):  
Van-The Tran
Keyword(s):  
Computer Simulation ◽  
Rotation Angle ◽  
Computer Numerical Control ◽  
Helical Gear ◽  
Numerical Control ◽  
Production Costs ◽  
Parabolic Curve ◽  
Transmission Errors ◽  
Simulation Results ◽  
Center Distance

In the conventional hobbing process, a double-crowned involute helical gear is generated by the hob cutter with parabolic-curve tooth profiles for the cross-profile crowning and varied the center distance between the hob and work gear for the longitudinal crowning. Therefore, to cut a double-crowned helical gear not only requires at least four synchronous axes and hob cutter regrinding (which increases production costs) but also induces twisted tooth flanks on the generated work gear. In this paper, I propose a hobbing method by applying a modified work gear rotation angle that enables double-crowning of involute helical gear's tooth flanks using a standard hob cutter and a computer numerical control (CNC) hobbing machine with only three synchronous axes. The proposed method has also verified by using two computer simulation examples to compare the meshing-conditions, contact ellipses, and transmission errors of the double-crowned gear pairs with that produced by applying the conventional hobbing method. Computer simulation results reveal the advantages of the proposed novel hobbing method.

Research on Forms of Grinding Allowance Based on NC Form Grinding Cylinder Gear

2010 ◽  
Vol 42 ◽  
pp. 276-279
Author(s):  
Hong Xia He
Keyword(s):  
Numerical Control ◽  
Grinding Wheel ◽  
Axial Section ◽  
Gear Grinding ◽  
Form Grinding ◽  
Section Shape ◽  
Grinding Machine

The machining principle and characteristics of form grinding cylinder gear are introduced as well as the characteristics of form grinding machine in this paper. By analyzing and comparing three kinds of grinding allowance for cylinder gear grinding, a reasonable and effective axial section shape is determined in experience, which is a practical profile to shape the axial section of grinding wheel for numerical control grinding cylinder gears.

A Novel Finish Hobbing Methodology for Longitudinal Crowning of a Helical Gear With Twist-Free Tooth Flanks by Using Dual-Lead Hob Cutters

2014 ◽  
Author(s):  
Van-The Tran ◽  
Ruei-Hung Hsu ◽  
Chung-Biau Tsay
Keyword(s):  
Computer Simulation ◽  
Longitudinal Direction ◽  
Helical Gear ◽  
Tooth Profile ◽  
Second Order ◽  
Order Function ◽  
Helical Gears ◽  
Pressure Angle ◽  
Dual Lead ◽  
Tooth Flank

In the gear finish hobbing process, to obtain a twist-free tooth flank of helical gears, a novel hobbing method for longitudinal crowning is proposed by applying a new hob’s diagonal feed motion with a dual-lead hob cutter. Wherein the hob’s diagonal feed motion is set as a second order function of hob’s traverse movement and tooth profile of hob cutter is modified in a dual-lead form with pressure angle changed in it’s longitudinal direction. The proposed method is verified by using two computer simulation examples to compare topographies of the crowned work gear surfaces hobbed by the standard and dual-lead rack cutters. The results reveal the superiority of the proposed novel finish hobbing method.

scholarly journals Closed-Loop Feedback Flank Errors Correction of Topographic Modification of Helical Gears Based on Form Grinding

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Huiliang Wang ◽  
Jubo Li ◽  
Yang Gao ◽  
Jianjun Yang
Keyword(s):  
Closed Loop ◽  
Correction Method ◽  
Numerical Control ◽  
Grinding Wheel ◽  
Helical Gears ◽  
Form Grinding ◽  
Loop Feedback ◽  
Feedback Correction ◽  
Closed Loop Feedback ◽  
Tooth Flank

To increase quality, reduce heavy-duty gear noise, and avoid edge contact in manufacturing helical gears, a closed-loop feedback correction method in topographic modification tooth flank is proposed based on the gear form grinding. Equations of grinding wheel profile and grinding wheel additional radial motion are derived according to tooth segmented profile modification and longitudinal modification. Combined with gear form grinding kinematics principles, the equations of motion for each axis of five-axis computer numerical control forming grinding machine are established. Such topographical modification is achieved in gear form grinding with on-machine measurement. Based on a sensitivity analysis of polynomial coefficients of axis motion and the topographic flank errors by on-machine measuring, the corrections are determined through an optimization process that targets minimization of the tooth flank errors. A numerical example of gear grinding, including on-machine measurement and closed-loop feedback correction completing process, is presented. The validity of this flank correction method is demonstrated for tooth flank errors that are reduced. The approach is useful to precision manufacturing of spiral bevel and hypoid gears, too.

Research on Evaluation Method of CNC Gear Form Grinding Processing Performance

2014 ◽  
Vol 635-637 ◽  
pp. 1944-1947
Author(s):  
Hui Liang Wang ◽  
Yu Quan Xiong ◽  
Jian Jun Yang ◽  
Kai Xu
Keyword(s):  
Performance Evaluation ◽  
Evaluation Method ◽  
Integrated Model ◽  
Numerical Control ◽  
Tooth Surface ◽  
Machining Performance ◽  
Research On Evaluation ◽  
Gear Grinding ◽  
Grinding Machine

To analyze the machining performance of grinding machine and improve the quality of tooth surface, this paper proposes an integrated model of processing performance evaluation of computer numerical control gear grinding machine. Based on the gear profile grinding machine kinematics principles, the topology modification formulas of tooth surface were deduced. Calculated the process capability index according to experimental data and found that the tooth surface errors were followed normal distribution. The main reason of formation errors was analyzed by cause and effect diagram. Finally, the validity of this integrated model of processing performance evaluation is numerically demonstrated using CNC gear grinding machine.

Laser Holographic Measurement of Tooth Flank Form of Cylindrical Involute Gear: Part 2 — For Helical Gear Tooth

1992 ◽  
Author(s):  
H. Fujio ◽  
A. Kubo ◽  
S. Tochimoto ◽  
H. Hanaki ◽  
S. Saitoh ◽  
...  
Keyword(s):  
Gear Tooth ◽  
Measuring Method ◽  
Helix Angle ◽  
Helical Gear ◽  
Helical Gears ◽  
Error Surface ◽  
Tooth Flank ◽  
Form Deviation ◽  
Laser Holography ◽  
Holographic Measurement

Abstract The interferometry using laser holography is applied to measure the form deviation of tooth flank of involute helical gears. One problem of this method is that the increase of helix angle reduces the region of the flank to which the laser beam can irradiate at a same time. To solve this problem, following method is developed: The objective tooth flank is divided into some regions, and the interferometry measurement is worked out for each region. The measured values for the form deviation of each region of the tooth flank are transformed to the values on the plane of action of this gear. These values for each region of the tooth flank are then concatenated successively until they result the curved surface for the form deviation of the whole tooth flank of the helical gear. The error surface of the tooth flank of helical gear obtained by this procedure is compared with that of conventional measuring method using contacting stylus.

scholarly journals Sensorless balance method for the spindle system of computer numerical control gear grinding machine

2018 ◽  
Vol 51 (9-10) ◽  
pp. 460-469 ◽  
Author(s):  
Yong Li ◽  
Shaoping Zhou
Keyword(s):  
Axial Direction ◽  
Computer Numerical Control ◽  
Balance Method ◽  
Numerical Control ◽  
Influence Coefficient ◽  
Residual Vibration ◽  
Gear Grinding ◽  
Influence Coefficient Method ◽  
Grinding Machine ◽  
Coefficient Method

Background: Spindle imbalance vibration of the computer numerical control grinding machine may result in dramatic effects on tool wear, surface finish, and form-holding of the products, which makes the balancing procedure very essential during their manufacturing process. Although the spindle residual vibration in a single direction can be suppressed effectively by the commonly used commercial balance systems, some real-world application results show that most of these balance systems cannot reduce the spindle residual vibration in horizontal, vertical, and axial direction simultaneously. Methods: To overcome this issue, the limitation of commonly used influence coefficient method–based spindle balance method is discussed first. After that, a novel balance method is experimentally proposed for the spindle vibration control using the position fluctuation information between the carriage and guideway of the servo-axis. In this method, the position fluctuation information between the carriage and guideway and the key phase information are practically measured using the built-in linear scale and spindle servomotor encoder, respectively, in which the position fluctuation information between the carriage and guideway can be considered as an integrated representation of the spindle imbalance vibration. Combined with the influence coefficient method, the imbalance vibration presenting in the horizontal, vertical, and axial direction of the spindle can be suppressed simultaneously and effectively. Results and Conclusions: A field balancing experiment is carried out on a high-precision computer numerical control gear grinding machine. Experiment results demonstrate that, compared with the commonly used commercial balancing system, the proposed method can not only reduce the residual vibration amplitude at the objective balancing speed effectively but also reduce the residual vibration amplitude more than 50% simultaneously in each direction during the whole run-down process.

scholarly journals Thermal characteristic analysis of Z-axis guideway based on thermal contact resistance

2018 ◽  
Vol 10 (10) ◽  
pp. 168781401880532 ◽  
Author(s):  
Jiandu Ji ◽  
Rongjing Hong ◽  
Fuzhong Sun ◽  
Xiaodiao Huang
Keyword(s):  
Finite Element ◽  
Contact Resistance ◽  
Machine Tool ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Numerical Control ◽  
Feeding System ◽  
Large Computer ◽  
Gear Grinding ◽  
Grinding Machine

The Z-axis feeding system of large computer numerical control (CNC) gear grinding machine tools generates lots of heat during processing, which leads to tilt and pitch deformation of the Z-axis guideway and reduces the machining accuracy. In view of this situation, a three-dimensional finite element analysis method is proposed to conduct transient thermal-structural coupling analysis of the Z-axis guideway and feeding system. Considering the microscopic contact state on machine tool joint surfaces and using the root mean square measurement method, the fractal parameter is identified and the thermal contact resistance at the joints is calculated. The friction heat on the guideway is calculated and the thermal value of the motor is obtained. Then, the heat generation rate of the bearing and the screw nut is calculated according to the friction torque. The convective heat transfer coefficient is determined according to the Reynolds number and the Nusselt number. The finite element model is established to obtain the finite element simulation results of thermal error. Finally, the experimental platform for measuring the temperature and thermal deformation of the large computer numerical control gear grinding machine tool is set up, and the accuracy and reliability of the method is verified.

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