Abstract:
The synergy between gear hobbing and honing processes, focusing on the pre-modification of gear teeth during gear hobbing to optimize the honing stock control. By leveraging the principles of gear manufacturing and advanced mathematical modeling, this study proposes a method to enhance gear quality and processing efficiency. The research is supported by virtual simulation experiments conducted in VERICUT software, validating the effectiveness of the proposed approach.
1. Introduction
Gear manufacturing is a crucial aspect of mechanical engineering, with gear hobbing and honing being two significant processes in gear production. Gear hobbing, known for its high efficiency and low cost, is primarily used for rough and semi-finish machining of gears. On the other hand, honing, as a precision finishing technique, is employed to achieve high accuracy and surface finish on hardened gear teeth. This paper explores the synergy between these two processes, particularly focusing on pre-modification during gear hobbing to facilitate subsequent honing operations.
2. Literature Review
2.1 Research Status of Gear Hobbing
Gear hobbing involves the use of a hob, which resembles a worm gear, to generate gear teeth on a workpiece. The process is based on the principle of gear meshing, where the hob and workpiece axes are arranged at a specific angle to ensure correct tooth profile generation. Advances in gear hobbing technology have led to improved accuracy and surface finish, making it a preferred choice for rough and semi-finish machining.
2.2 Research Status of Gear Honing
Honing is a finishing process that employs abrasive honing wheels to remove material from the gear teeth, achieving high precision and surface quality. The process is characterized by the forced meshing between the honing wheel and the gear teeth, resulting in material removal along the tooth width. Honing is widely used for hardened gear surfaces, enhancing their mechanical properties and performance.
2.3 Research Status of Tooth Surface Modification Techniques
Tooth surface modification techniques, such as tooth profile modification, tooth trace modification, and topological modification, are employed to improve gear performance. These techniques involve altering the tooth shape and orientation to optimize contact conditions, reduce vibration and noise, and enhance load distribution. Various methods have been proposed for modifying gear teeth, including the use of B-spline curves for lead modification [37], inverse envelope method for scraper tool design [38], and adjustment of hob rake angle for high-order tooth profile modification [39].
3. Theoretical Background
3.1 Principles of Gear Hobbing
Gear hobbing relies on the intermeshing of the hob and workpiece to generate the gear tooth profile. The hob, with its spiral cutting edges, moves along the workpiece axis while rotating, creating a spatial trajectory that forms the gear tooth. The correct tooth profile is achieved by adjusting the angle between the hob and workpiece axes (axis crossing angle Σ), determined by the hob helix angle βh and gear helix angle βg.
Table 1: Key Parameters in Gear Hobbing
| Parameter | Description | Symbol |
|---|---|---|
| Axis crossing angle | Angle between hob and workpiece axes | Σ |
| Hob helix angle | Angle of hob spiral cutting edges | βh |
| Gear helix angle | Angle of gear spiral tooth profile | βg |
| Hob head number | Number of cutting edges on the hob | Zh |
| Gear tooth number | Number of teeth on the gear | Zg |
3.2 Principles of Gear Honing
Gear honing involves the use of abrasive honing wheels to remove material from the gear teeth. The honing wheel, with its abrasive grains, meshes with the gear teeth and removes material through friction and wear. The process is controlled by adjusting the honing wheel’s position, speed, and pressure to achieve the desired tooth profile and surface finish.
4. Methodology
4.1 Gear Tooth Pre-modification for Hobbing
To facilitate subsequent honing operations, this study proposes pre-modification of gear teeth during gear hobbing. The objective is to optimize the honing stock distribution by altering the tooth profile and orientation during gear hobbing process. This is achieved through topological modification, where the tooth surface is altered to improve load distribution and reduce vibration and noise.
4.2 Mathematical Modeling
Mathematical models are developed to describe the geometric relationships between the hob, workpiece, and resulting tooth profile. These models include equations for tooth profile generation, hob and workpiece motion, and material removal during honing. Sensitivity matrices are also derived to analyze the impact of modification parameters on the resulting tooth profile.
Table 2: Sensitivity Matrix Components
| Sensitivity Matrix Component | Description |
|---|---|
| ∂z/∂xh | Partial derivative of tooth surface height with respect to hob axial position |
| ∂z/∂yh | Partial derivative of tooth surface height with respect to hob radial position |
| ∂z/∂φh | Partial derivative of tooth surface height with respect to hob rotational angle |
| … | … |
4.3 Virtual Simulation in VERICUT
To validate the proposed method, virtual simulation experiments are conducted in VERICUT software. The software provides a platform for simulating machining processes, allowing for the analysis and optimization of tool paths, machine settings, and resulting workpiece geometry.
5. Experimental Results and Analysis
5.1 Virtual Simulation Setup
The virtual simulation setup includes the creation of a 3D model of gear hobbing machine, configuration of the virtual machine in VERICUT, and import of the hob and workpiece models. The machine’s motion relationships are defined based on the theoretical models developed in Section 4.2.
5.2 Simulation Results
The simulation results show the tooth profile generated during gear hobbing process, including any modifications applied. The results are analyzed to evaluate the effectiveness of the pre-modification in optimizing the honing stock distribution.
5.3 Comparison with Theoretical Models
The simulated tooth profiles are compared with the theoretical models to validate the accuracy of the proposed method. The comparison includes an analysis of tooth profile deviations, surface finish, and material removal rates.
Table 3: Comparison of Simulated and Theoretical Results
| Parameter | Simulated Result | Theoretical Result | Deviation |
|---|---|---|---|
| Tooth profile height | z_sim | z_th | |
| Surface roughness | Ra_sim | Ra_th | |
| Material removal rate | MRR_sim | MRR_th |
6. Conclusion
The method for gear tooth pre-modification during gear hobbing to optimize honing stock control. The proposed method is based on topological modification of the tooth surface, achieved through adjustments to gear hobbing process parameters. Virtual simulation experiments conducted in VERICUT validate the effectiveness of the proposed method in improving gear quality and processing efficiency.