Exploring the Boundaries of Electrically Induced Bearing Damage in Grease-Lubricated Rolling Contacts

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

You have carried out extensive experimental work and achieved interesting results. I have only a few comments:

• you present an own idea of a pit formation with Fig.1. This is remarkable . And I hope you obtain an interesting discussion from the audience. I for myself can not agree to the picture a) where you present e direct contact of two asperities. I think it is not possible to go through a lubricant film (you need an infinity force to get a filmthickness=0). But its your opinion and I hope you get some comments !

• its a pity that you have not discussed the behavior of different types of greases. May be in the next step

• I think it's a bit unfortunate that you have select a PU grease. Would be get more interesting to see the behavior of a Li-grease.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1.The test results show that the severity of electrical damage is related to track length, sliding speed and movement mode. What is the fundamental cause? It is best to explain from the perspective of the mechanism of electrical erosion damage.

2.When the bearings of new energy vehicles work, the shaft current of the bearings is AC or DC?

Under the action of two types of shaft currents, are the characteristics of electrical damage on the bearing raceway surface consistent? It's better to give an explanation.

3. Is it appropriate to simulate the electric damage of bearings with only DC shaft current? Is it more appropriate to analyze the electric damage test of bearings with AC shaft current?

4.The description of test parameters and conditions is not clear, which makes it impossible to reproduce them. It is suggested to supplement the test conditions such as ball size, radial load, roughness and voltage parameters. At the same time, it is better to give the contact state of the ball and disc under the test conditions, such as the Hertz contact area, contact stress, oil film thickness, film formation state, etc.

Comments on the Quality of English Language

1. Use more professional descriptions

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Very interesting and elegant work. My congratulations to the authors. I appreciate that they reported the test conditions when pitting was not found. That brings a better understanding of the complex phenomena.

I have only two optional suggestions:

- on item 2.2 include the ISO unit values between brackets when only imperial units (as inches) were used.

- include in the table or in the text the number of load cycles for each of the test conditions

Author Response

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Reviewer 4 Report

Comments and Suggestions for Authors

1.The abstract needs to be revised. The abstract should be condensed and brief. It is recommended that the findings and significance of the study sections be highlighted.

2.In the introductory section, (1) what is meant by the 2" in Figure 3a? (2) The concluding section should briefly describe the main purpose of the work and highlight its main conclusions. Please indicate where?

3.Figure 4 shows the test device, what the scope of the device is, what its strengths and weaknesses are, and whether it is at the forefront of current scientific research.

4. Figure 6 shows SEM images of wear marks on a flat sample after testing at the highest and lowest speeds. Is it possible to add an SEM image of wear marks on a flat sample tested at an average speed?

5.The extended orbital reciprocation test in chapter 5.3.3 is an improvement test for this paper; is this improvement serendipitous? Is this a continuation of the completion of previous research? If so, please cite the relevant references.

6.It is recommended that chapters 4 and 5 state, point by point, paragraph by paragraph, the conclusions of the experiment, as well as the shortcomings of the study, and the outlook of the article.

7.the formatting issues in this paper need a lot of improvement. (1) No spaces between 1. introductions. (2) References should be cited uniformly. Suggestions are [1,2,3,4]. (3) Each picture name should be followed by "." (4) Strictly organise the format of references to be uniform.

Comments on the Quality of English Language

Please improve the quality of English editing as appropriate.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

NO.

Comments on the Quality of English Language

NO.

Reviewer 4 Report

Comments and Suggestions for Authors

Accept in present form