Dynamic Performance Analysis of Cage in Four-Point Contact Ball Bearing

Round 1

Reviewer 1 Report

The presented research compares multi-body dynamic simulations with experiments of four-point contact ball bearings. The paper starts with a brief introduction to ‘four-contact-point ball bearings’ (l.10), which I more often encounter as ‘four-point contact ball bearings’. Please compare the naming with the naming of regular manufacturers and consider changing the wording. A train gear box is designated as use case for these bearings. Since these bearings are used in special conditions, please refer to the inevitable use of the bearings in this application. If possible, a view of the gear box design with the bearing would greatly increase the comprehensibility. Furthermore, a comparison with angular and axial ball bearings is recommended for better differentiation of the bearing types. 
The presented state of the art lacks international (global) authors. Please extend the number of references to roundabout 30, which is a usual value for high quality papers. The references are listed and coarsely described in each one sentence. Please consider a closer connection between the presented literature and the aim of the presented research. 
The aim of the research should be focused on in section 1 at the end. What dangers result of the wobbling cage in the bearing? Extend the description of the aim of the research with a close description of the software (version) and its company. I like the general design of the research since it is easily comprehensible and the comparison between simulation and experiment is done with nearly the same values. Software addons such as Python interfaces are hardly free available or described in references. Please add your code to the paper as further material. A more precise description of the Adams model is required. What type of bodies are used? Did you consider some simplifications? How did you encounter with the sliding and stiction in MSC Adams?
Mainly, the evaluation is done with the trajectory of the cage centroid. Since - except for the outer ring - the bodies have degrees of freedom, a small section in the paper should present their movements and compare them to the motions of the cage. Beside the motions, the contact forces are an indicator for the movements, too. Have you checked the curves of the contact forces and analyzed them?
The experimental setup is ok. However, adding a torque sensor allows to analyze vibrations in the drive system, which can affect the movement of the cage. In figure 9, replace test shaft with bearing, because you are not testing the shaft but the bearing. In the description of the figure: Why is rolling spelled capital? The technical design in figure 10 indicates contact between test shaft and rear cover end. Please enlarge the figure to rule out, that there is no contact. In further studies add torque or acceleration sensors and compare their measurements with the movements of your test object. Figure 13a shows multiple lines, which are closely together. The reader hardly gets any information about the comparison of the curves but only about the absolute sizes of the average speeds. 
Starting in line 314, the description of the deviations is presented. You write ‘main’ reason, are there side reasons? Please extend the description about the grease lubrication because the argumentation is not finished with the given text in my opinion. Add a close description about the differences between the cage velocities. Since you run the same speed on the inner ring, the differences rise from different slide to roll values in the contact. Take a close look to the Adams contact definition and show possible solutions this situation. Please carefully revise the term ‘correctness of the simulation’.
In general, please avoid discussions in the result section (cf. lines 200ff, 228ff, 314ff). Discussion/ conclusion is one chapter after presenting the results. The conclusion 1 names the ‘collision force’. Please add a section to the paper in which the collisions between the parts are addressed. Especially since the cage of the bearings is probably guided at the outer ring, the collision forces are an important element. The comprehension in point 2, point 3 and point 4 is ok, but must be improved by replacing the multiple uses of increase and decrease. Consider renaming the ‘correctness’ of the simulation in point 5. At the end add an outlook of the research and similar bearings, which can profit from your research.
In general, a major revision of the English language is necessary. Put an article in the title in front of ‘Cage’. Further articles are recommended e. g. in lines 58 or 135. For improved readability, I recommend limiting the length of sentences to a maximum of 30 words (cf. sentences in lines 17, 70, 126, 327 or 346). Some doubled words occur in the text (cf. line 90 restrain, line 338 it can be seen). Another example is the multiple use of ‘increase’ and ‘decrease’ throughout the paper. Especially in the last section, these words are used more than 10 times.
At the end, I like to invite the authors to resubmit their adapted paper. I really like the structure of your research. Compared to other papers, your results have great potential for the transfer to different bearings systems with e. g. different dimensions or different lubrications or in different applications. I am happy to reassess you work.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Li et al.,

 

The manuscript “Dynamic Performance Analysis of Cage in Four-contact-point Ball Bearing” (lubricants-1704692) by Li et al. study on the variation law of cage motion stability. The topic is interesting, but I think this article should reconsider after proper changes in major revision for publication in Lubricants. Some of my specific comments are below:

1. In the abstract section (line 10-22), the authors should add quantitative results rather than only qualitative results.
2. Describe the novelty of the article made by the author? From the results of my evaluation, it seems that many similar published works adequately explain what you have raised in the current manuscript related to dynamic evaluation of ball bearing. If there are something others really new in this manuscript, please highlight it more clearly in the introduction section (line 26-75).
3. The state of the art and the significance of the current study are not clearly present, the authors should highlight it more advanced in the introduction section (line 26-75).
4. It is crucial to explain more clearly why dynamic analysis of 4PBB is needed to studied in Introduction section (line 26-75). And, why not stgatic analysis of 4BB?
5. Since this manuscript evaluate of metallic bearing, I would encourage and advise the authors to adopt some of the specific additional references related to metal-on-metal bearing published by MDPI in the introduction section (line 26-75) as follow:

• • Tresca Stress Simulation of Metal-on-Metal Total Hip Arthroplasty during Normal Walking Activity. Materials (Basel). 2021, 14, 7554. https://doi.org/10.3390/ma14247554
  • The Effect of Bottom Profile Dimples on the Femoral Head on Wear in Metal-on-Metal Total Hip Arthroplasty. Journal of Functional Biomaterials. 2021, 12, 38. https://doi.org/10.3390/jfb12020038

6. The authors should add one systematic figure to illustrate the workflow of experimental testing in the present study to make the reader more interested and easier to understand rather than only using dominant text to explain.
7. The author must provide a detailed specification and use condition more detail regarding all tools used in the research carried out so that the reader can estimate the accuracy and differences in the results that the authors describe due to the use of different tools in future studies.
8. The authors are advised to compare the results they obtain with previous similar/identical studies if it is possible.
9. In the last paragraph before conclusion section (after line 344), the authors should add of one paragraph about the limitations of the presented review.
10. The conclusion (line 345-378) of the present manuscript is not solid. Further elaboration is needed. Also, make it intho paragraph, not point-by-point as in present form.
11. Further research needs to be explained in the conclusion section (line 345-378).
12. In the whole of the manuscript, the authors sometimes made a paragraph only consisting of one or two sentences that made the explanation not clearly understood. The authors need to extend their explanation to become a more comprehensive paragraph. In one paragraph, it is recommended to consist of at least 3 sentences with 1 sentence as the main sentence and the other sentences as supporting sentences. For example in line 338-340.
13. I see some errors on English in some areas of the present manuscript. To improve the quality of English used in this manuscript and make sure English language, grammar, punctuation, spelling, and overall style are correct, further proofreading is needed. As an alternative, the authors can use the MDPI English proofreading service for this issue.
14. Please make sure the authors have used the Lubricants, MDPI format correctly. The authors can download published manuscripts by Lubricants, MDPI, and compare them with the present author's manuscript to ensure typesetting is appropriate. For example: Institutional Review Board Statement, Informed Consent Statement, and Data Availability Statement is missing that should be put after conclusion and before references..

 

Best regards,

The Reviewer

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Will benefit from language editing; examples:

• Abstract
  • Line 12/13: …dynamic performance of „the“ cage… or …of cage“s“…
  • Line 15: …established „using“ ADAMS…
  • Line 16: …of „the“ cage centroid…
  • Lin 20: delete „what’s more“; too colloquial
  • Line 21/21: …results, „a“ test bench „for“ rolling bearing cage“s“ is „developed“, and…
• Chapter 1.
  • Line 27: …high-speed railway“s“,…
  • Line 28: …of gearbox bearing“s“ in…
• Numerous further grammatical and other errors in all chapters (chapters 3 and 4 have less errors but still need editing)

 

Further comments:

Abstract

• Please explain „cage sliding“. Do you mean slippage? It might help the understanding, as sliding on the guiding diameter on either inner or outer ring is normal.
• Please explain „combined load“; is it meant as a combination of axial and radial load? Even though you explain it in other chapters, it would help the understanding of the Abstract

Chapter 4

• Line 201 and 232: Please explain „ferrule“; is it another part in the bearing model or do you mean the guiding ring by that? If a ring is meant, rather choose to call it „ring“
• Line 249: Please explain „eddy velocity“ or use another term; it is a rather unusual term in connection with rolling bearings

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear authors,

the changes you made are ok. Please ensure that you make some minor format corrections suchs as line 70 "in order" or the view of Table 1. This should be possible in the last step when you remove the red font color.

I strongly recommend limiting your publications in future to max. 15 pages. With your edits, you added 4 pages to the first version of your publication. With less text, you focus on the important results and you get more reads.

Kinds regards,

Reviewer 2 Report

Well done for the authors. I am recommending this manuscript for publication.