Dynamic Evolution Characteristics of the Gear Meshing Lubrication for Vehicle Transmission System
Round 1
Reviewer 1 Report
This paper presents aa modeling and solving method for gear meshing lubrication. The paper seems innovative and relevant. I would give the following comments about,
1. A notation list is suggested.
2. Although the simulation is not easy task, the experimental verification is even more important. The experimental details should be supplemented in the paper.
Author Response
This paper presents a modeling and solving method for gear meshing lubrication. The paper seems innovative and relevant. I would give the following comments about
Response: Thanks for your helpful advice. We propose a modeling and solving method for gear meshing lubrication and thermal transfer features. We would improve the manuscript continuously, and wish it could match the publication requirements of Processes.
- A notation list is suggested.
Response: Thanks for your helpful advice. We have add a Nomenclature list.
- Although the simulation is not easy task, the experimental verification is even more important. The experimental details should be supplemented in the paper.
Response: Thanks for your helpful advice and positive comments. We add some discussions with the other references to verify the numerical method. When the rotation direction of the gear is the same, the gear's resistance moment in-creases with the rotational speed, and then the power loss of the gear increases. The above characteristics is agreement with the numerical results of Mo et al. [45].
Reviewer 2 Report
1. Although the numerical simulation strategy can be useful to the readers, it primary limitation is that Black box approach did not explain the inherent mechanisms that lead this variability in the performance characteristics.
2. Abstract should be given as more interesting. Express at least one of the main aspects and features of the paper.
3. Improve the conclusion part of the Abstract.
4. Research gap studies are uncleared.
1. Further, results and discussion of simulations should be compared with previous researchers by citing references.
Provide the error bars in Figures 5 and 7.
1. Improve the conclusion section.
Please prove the information related scope for future work of the present investigation.
2. Manuscript must be presented in highlight the contribution, and applicability of the work.
3. Please check the manuscript for wrong choice of words, grammatical errors and incoherent sentence structure.
Author Response
1. Although the numerical simulation strategy can be useful to the readers, it primary limitation is that Black box approach did not explain the inherent mechanisms that lead this variability in the performance characteristics.
Response: Thanks for your helpful advice and positive comments. We have added some discussion to explain the inherent mechanisms. In the working process of the gearbox, high-speed rotation of gears, meshing friction, and overcoming fluid work will release a lot of heat. Heat accumulation will lead to a rapid rise in temperature inside the gearbox in a short time. The high temperature in the box will not only affect the transmission efficiency of the gear but also increase the failure rate in the working process of the gear, thus causing damage to the gear and the box.
2. Abstract should be given as more interesting. Express at least one of the main aspects and features of the paper.
Response: Thanks for your helpful advice and positive comments. We have revised the abstract. Here, the dynamic evolution process and thermal transfer characteristics of lubricating oil fields during gear meshing is the essential physical process to improve transmission heat dissipation. This paper presents a modeling and solving method for gear meshing lubrication and thermal transfer features based on the volume of fluid model and piecewise linear interface construction (VOF-PLIC). The dynamic mesh technique combines spring smoothing and reconstruction to optimize the numerical solution process. The dynamic evolution law of gear meshing lubrication and thermal transfer is obtained by analyzing the lubrication evolution process under different speed/steering conditions. The results show that the proposed modeling and solving method can well reveal the lubrication and thermal transfer laws of the gear meshing. The temperature of the gear meshing regions is higher than that in the other regions, and the lubrication temperature takes on linear increasing trend with the stirring process. As the gear speed rises, the meshing resistance moment increases, the transmission power loss increases, and the temperature of the lubrication oil is larger than that of the gearbox. The power loss under the clockwise rotation of the driving gear G4 is higher than that under the counterclockwise rotation of the driving gear. (Highlight in yellow colour).
3. Improve the conclusion part of the Abstract.
Response: Thanks for your helpful advice and positive comments. We have revised the abstract. The results show that the proposed modeling and solving method can well reveal the lubrication and thermal transfer laws of the gear meshing. The temperature of the gear meshing regions is higher than that in the other regions, and the lubrication temperature takes on linear increasing trend with the stirring process. As the gear speed rises, the meshing resistance moment increases, the transmission power loss increases, and the temperature of the lubrication oil is larger than that of the gearbox. The power loss under the clockwise rotation of the driving gear G4 is higher than that under the counterclockwise rotation of the driving gear. (Highlight in yellow colour).
4. Research gap studies are uncleared.
Response: Thanks for your helpful advice. We have revised the research gap. Currently, the research on the lubrication process of gear transmission mainly focuses on the simple gear meshing state and disturbance factors. For the multilevel gear meshing process, the dynamic evolution law and thermal transfer mechanism of the hot oil field of the gear meshing process is still unclear. The modeling and solving optimization method for the gear meshing lubrication faces great difficulty. (Highlight in yellow colour).
5. Further, results and discussion of simulations should be compared with previous researchers by citing references.
Response: Thanks for your helpful advice and positive comments. We add some discussions with the other references to verify the numerical method. When the rotation direction of the gear is the same, the gear's resistance moment in-creases with the rotational speed, and then the power loss of the gear increases. The above characteristics is agreement with the numerical results of Mo et al. [45].
6. Provide the error bars in Figures 5 and 7.
Response: Thanks for your helpful advice and positive comments. We have revised the Figures.
7. Improve the conclusion section.
Response: Thanks for your helpful advice and positive comments. We have revised the conclusions.
1) A VOF-PLIC modeling and solving method of the gear lubrication and thermal transfer process is presented. The lubricating oil fully lubricates the gear meshing zone, and the lubricating oil is evenly distributed in the meshing zone. As the gear speed increases, the oil resistance overcome by the gear rotation becomes smaller and smaller until it reaches a steady state.
2) For the thermal transfer process, the temperature of the gear meshing regions is higher, the gear will release more heat in the working process, resulting in a linear increase in the box temperature at the beginning stage. The temperature of stirring oil increases linearly with the process of stirring.
3) With the increase of rotational speed, the resistance moment of the gear increases, the power loss of the gear increases. With the gear speed rises, the gearbox's maximum temperature and lubricating oil temperature increase significantly, and the overall temperature rises considerably under the counterclockwise rotation condition. (Highlight in yellow colour).
8. Please prove the information related scope for future work of the present investigation.
Response: Thanks for your helpful advice and positive comments. Subsequent studies will explore facets of the multiphase coupled mechanism and fractal dimensions of lubrication flow pattern and fluid-solid vibration characteristics of the gear meshing lubrication. (Highlight in yellow colour).
9. Manuscript must be presented in highlight the contribution, and applicability of the work.
Response: Thanks for your helpful advice and positive comments. In summary, the main contribution of this paper is proposing a dynamic modeling and solving method for the hot fluid field of gear meshing lubrication. It can supply a helpful reference for research on dynamic analysis and thermal transfer process of automobile transmission lubrication and have general engineering value for transmission tooth profile design and lubrication optimization. (Highlight in yellow colour).
10. Please check the manuscript for wrong choice of words, grammatical errors and incoherent sentence structure.
Response: Thanks for your helpful advice and positive comments. We have check the manuscript.
Round 2
Reviewer 1 Report
My comments have been carefully revised, and I have no further comment.
Author Response
Thanks for your helpful advice and positive comments. The numerical calculation is based on the ANSYS commercial software. The multiphase fluid domain is divided by the Tetrahedral grid, and the number of the total mesh is 453426. The mesh quality is adjusted to the highest specification (above 0.8), which can meet the transient calculation accuracy.
Reviewer 2 Report
Authors have made significant changes in the revised manuscript. Hence, consider the manuscript for publication in its present form.
Author Response
Thanks for your helpful advice and positive comments. The numerical calculation is based on the ANSYS commercial software. The multiphase fluid domain is divided by the Tetrahedral grid, and the number of the total mesh is 453426. The mesh quality is adjusted to the highest specification (above 0.8), which can meet the transient calculation accuracy.
