The Modularized Development of a Wheel-Side Electric Drive System Using the Process of Hobbing and Form Grinding
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript is basically well structured, but I would like to make a few comments, observations, and questions:
Line 91 should be moved to a new page.
Can the drive system presented be used only for the rear (non-steered) wheels?
Isn't the manufacturing cost more than using a traditional suspension and two half-axles (the two-motor solution can remain, then there is no need for a differential)? Here is a cast/milled metal housing with gears inside, the manufacturing cost of which may be higher.
How much does the efficiency of the gear drive degrade (if at all) the efficiency of the drive compared to a traditional half-shaft solution?
It is not clear why the intermediate shaft is needed along with the extra two gears. I assume it is because of the length of the "swingarm"? Has there been any solution to eliminate this? (For example, moving the motor closer, or if that is not possible, a chain or belt drive.)
Which version does the gear data in Table 2 apply to?
The caption Fig.9 should be corrected (the other figures have Figure).
The differences between the three gear versions should be better highlighted, as well as how they differ from traditional gears. Why was this analysis necessary? Gears have been used in the drive of various vehicles for quite some time, and their production has also been solved.
In Table 3, what units of measurement are used for columns 3 and 4?
Shouldn't line 380 refer to Figure 16?
Line 428 should be moved to a new page.
Which version was the test in section 4.2 performed with?
Author Response
Thank you for your valuable comments. After reflection and improvement, my feedback is as follows.
- As you mentioned, currently there are the two-motor solution with the traditional suspension and half shaft, which can achieve the similar function of independent control of each wheel. Compared to that configuration, the wheel-side electric drive system can be regarded as a melting of the suspension system, which is more compact and modularized. In the technical trend of wire-by-chassis, the wheel-side electric drive system has the potential to be integrated and upgraded with the brake system and active suspension system. In this way, the actuators are all located near the wheel-end, which can be quick-response and safety-redundant. This architecture is especially suitable for future autonomous vehicles. The central controller is responsible for decision-making, and the actuator at the wheel end is responsible for rapid response.
- In terms of cost bill, there are two housings on each side, while the two-motor configuration has a centralized integrated housing. Although the half shaft and CVJ is eliminated, the cost increase caused by the housing is still greater than that of the half shaft.
- In terms of transmission efficiency, the wheel-side electric drive system has the advantage of short transmission chain. Due to its compact structure, the gear meshing loss and oil stirring loss are smaller than those of the centralized electric drive system. Although there are overlaps on both sides, there are considerable transmission losses in the differential and CVJ. According to our experimental data, the transmission efficiency of a single EDS is about 98~99% at low speed and high torque conditions, and about 96~97% at high speed and low torque conditions.
- Currently the wheel-side electric drive system has the design parameters for the trailing arm suspension system, which is for the rear (non-steered) wheels. If with the steering wheels, the suspension arm should be the form of Mcpherson suspension or double-wishbone suspension, but the dimension parameters of the wheel-side electric drive system must be optimized to be more compact.
- I agree that the innovation points and engineering goals need to be emphasized more. To address the novelty more clearly, I rewrite the introduction part, conclusion part, and the abstract.
- I agree with all the format error that you pointed out. I’ve updated with the latest file version where the modified parts are marked with the yellow background. Please check it, thank you.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript does not look like a research paper but as a manufacturing manual. The main issue is the lack of research questions. The introduction of a research paper sets the stage for your work and provides readers with the necessary background to understand its importance. In the provided manuscript, this part is very short (lines 63-83). The specific issue is not adequately addressed, there is no highlight of the gaps in existing research or unresolved issues that the study aims to tackle. Objectives (what authors want to solve) are not presented.
A considerable part of the manuscript (pages 3-5) is just a description of the object.
The methodology part is combined with the simulation and well presented. However, the results (in Section 4) are poorly presented due to a lack of research questions. There is no description of improvements or innovation in this part.
Conclusions are very general and not tied to the research results.
Moreover, due to the bad structure of the research, the abstract section is also not acceptable.
Author Response
Thank you for your valuable comments. After reflection and improvement, I agree with your point that the innovation and novelty are not clearly introduced. The real problem that I am trying to solve is the modularized development not just the assembly form but the component tolerance for various conditions. The wheel-side electric drive system is supposed to be applied in different vehicle models. The traditional durability development for a certain kind of vehicle load spectrum case by case can not meet the requirement of highly modularized development. For example, if the wheel-side electric drive system is applied in 3 models with different working conditions, then the bench test will spend over 4,500 hours, which is totally unacceptable in time cost and financial expense. To achieve a high-efficient development with enough credibility, the comprehensive load spectrum is irreplaceable, while the modeling accuracy is decisive for the simulation and test.
I agree that the innovation points and engineering goals need to be emphasized more. To address the novelty more clearly, I rewrite the introduction part, conclusion part, and the abstract. I’ve updated with the latest file version where the modified parts are marked with the yellow background. Please check it, thank you.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThank you for the answers, I accept them, and thus I accept the manuscript with the modifications and corrections.
Author Response
Thank you for your valuable comments. In order to address the novelty more clearly, I’ve updated the abstract of the article slightly. The precise modeling is crucial for the reliability of analysis results, so it is necessary to derive the geometric function of the tooth profile based on the tooling parameters. The modified part is marked with the yellow background in the latest file. Please check it, thank you.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe issues pointed out in the first review round were addressed. The introduction now points out the importance of precise tooth profile modelling. However, the main novelty of modelling should be highlighted to support the results and conclusion.
The description of the scientific contribution is critically important in a research paper. It serves as the paper's backbone, demonstrating your work's value, novelty, and relevance to the research community. A clear explanation of your scientific results will improve readability and understanding of your work. Moreover, it will increase the number of citations in your work.
Author Response
Thank you for your valuable comments. In order to address the novelty more clearly, I’ve updated the abstract of the article slightly. The precise modeling is crucial for the reliability of analysis results, so it is necessary to derive the geometric function of the tooth profile based on the tooling parameters. The modified part is marked with the yellow background in the latest file. Please check it, thank you.
Author Response File: Author Response.pdf
