Vibration Analysis of a Roller Bearing Condition Used in a Tangential Threshing Drum of a Combine Harvester for the Smooth and Continuous Performance of Agricultural Crop Harvesting
Round 1
Reviewer 1 Report
1. The "tangential threshing condition" in the title is not a commonly used professional vocabulary. It is recommended to replace it with a more accurate professional vocabulary.
2. The reference [7] does not mention that the accelerometer should be mounted at 45° with the horizontal radial axis, nor does it give the reason for such installation, and whether the author has quoted the wrong document.
3. The author proposes to adjust the speed of threshing drum by adjusting the speed of engine（line 98-100）. However, the engine is the power source of the whole harvester, and its speed adjustment will affect all working parts, making them unable to harvest grains normally. Please explain the rationality and reason of this speed regulation method and selection of 220，290，410，470 RPMs.
4. The test requirements in lines 118 to 133 are common sense and principled., No specific measures are given to realize these requirements. It seems that such content should not appear in research papers.
5. The content of Figure 7 is inconsistent with the description of line 181 in the text.
6. The mass of the accelerometer relative to the support is not negligible. The modal frequencies of the two devices will be significantly reduced after they are mounted together. Similarly, the modal frequencies obtained by modal simulation calculation of each part alone cannot prove that the modal frequencies of the whole device will not be the same as the excitation frequency. It is suggested that the author give the modal frequency of threshing drum.
Author Response
Thank you for your valuable comments and suggestions. We have edited our manuscript to include the comments which have helped to improve the quality of our research article. Please find the changes detailed as follows:
Point 1: The "tangential threshing condition" in the title is not a commonly used professional vocabulary. It is recommended to replace it with a more accurate professional vocabulary.
Response 1: Thank you for the suggestion. We decided to change the title to “Vibration analysis of roller bearing of a tangential threshing drum of combine harvester for the smooth and continuous performance of agricultural crop harvesting”
Point 2: The reference [7] does not mention that the accelerometer should be mounted at 45° with the horizontal radial axis, nor does it give the reason for such installation, and whether the author has quoted the wrong document
Response 2: Thank you for the review. The citation has been improved (Line 50).
Point 3: The author proposes to adjust the speed of threshing drum by adjusting the speed of engine（line 98-100）. However, the engine is the power source of the whole harvester, and its speed adjustment will affect all working parts, making them unable to harvest grains normally. Please explain the rationality and reason of this speed regulation method and selection of 220，290，410，470 RPMs.
Response 3: Thank you for the suggestion. These engine speeds mentioned are considered from the real operating speed during the harvesting period on a farm from low to a high-speed range which was obtained from the operators themself and the corresponding speed at a threshing unit is obtained from the inbuilt sensor mounted in Massey Ferguson series of combine harvester. The explanation is now mentioned in the manuscript (Lines 108-112).
Point 4: The test requirements in lines 118 to 133 are common sense and principled., No specific measures are given to realize these requirements. It seems that such content should not appear in research papers.
Response 4: Thank you for the suggestion. Those texts are removed from the manuscript (lines 118 to 133).
Point 5: The content of Figure 7 is inconsistent with the description of line 181 in the text.
Response 5: Thank you for the review. The texts have been improved on the manuscript by performing the modal analysis of the assembled threshing drum (Figure 7).
Point 6: The mass of the accelerometer relative to the support is not negligible. The modal frequencies of the two devices will be significantly reduced after they are mounted together. Similarly, the modal frequencies obtained by modal simulation calculation of each part alone cannot prove that the modal frequencies of the whole device will not be the same as the excitation frequency. It is suggested that the author give the modal frequency of threshing drum.
Response 6: In this research, the modal analysis of the components and the bracket separately is intended only for performing the comparative study of the natural frequencies to avoid resonance. Regarding your point, I have updated the assembled constrained modal analysis of the threshing drum (lines 196-213) to study deformation and mode shapes.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper introduces uncomplicated and effective method of bearing analysis of tangential unit of combine harvester to evaluate mechanical conditions like looseness, misalignment, and unbalance of the threshing unit. However, after a careful evaluation, I found the methodology is an easy combination of several Software and algorithms. Some of the major issues are listed as follows:
1. The title of this article is very broad and does not precisely summarize the object and content of the study. Further condensation is recommended.
2. The literature survey in the introduction should be updated. The following relevant articles should be referred in this section：Dynamic analysis for the thresher of a combined harvester subjected to stalk winding, AIP Advances, 2022. Actuators and Sensors for Application in Agricultural Robots: A Review. Machines. et al.
3. The threshing device given in figure 4 is only a disk-shaft structure, is it a sketch? Why no threshing rod teeth?
4. The authors mentioned “The mode shapes of the bracket are shown in figure 7.” in line 181. This is obviously wrong. The authors need to provide the correct modal calculations for the bracket.
5. It is better to improve the quality of all figures in this manuscript.
6. Where did the random input PSD load spectrum (Table 8) come from? Is it measured experimentally? It is not clearly explained in the paper.
7. The grammatical and spelling errors should be carefully corrected in the revision.
8.Figure 2, the sensor installation diagram in the left figure is not clear, and recommended to be modified. Whether all the accelerometers need to be installed as shown in Figure 2, this paper needs further explanation.
9.The composition and working principle of the bench need further explanation as shown in Figure 3. Tangential Threshing unit bearing test bench and Figure 3 should make the reader clear about the composition and working principle of the vibration test platform.
10.Figure 18 appears repeatedly in this paper, and is recommended to be simplified. The other pictures need further modification and standardization, such as figure 20.
Author Response
Thank you for your valuable comments and suggestions. We have edited our manuscript to include the comments which have helped to improve the quality of our research article. Please find the changes detailed as follows:
Point 1: The title of this article is very broad and does not precisely summarize the object and content of the study. Further condensation is recommended.
Response 1: Thank you for the suggestion. We decided to change the title to “Vibration analysis of roller bearing used in a tangential threshing drum of combine harvester for the smooth and continuous performance of agricultural crop harvesting”
Point 2: The literature survey in the introduction should be updated. The following relevant articles should be referred in this section：Dynamic analysis for the thresher of a combined harvester subjected to stalk winding, AIP Advances, 2022. Actuators and Sensors for Application in Agricultural Robots: A Review. Machines. et al.
Response 2: Thank you for the suggestion. The relevant high-profile article is included in the introduction of the manuscript (Lines 52-57). My research is based on non-loading threshing conditions. So I have focused on non-loading vibration analysis of agricultural machinery and some relevant general bearing analysis techniques.
Point 3: The threshing device given in figure 4 is only a disk-shaft structure, is it a sketch? Why no threshing rod teeth?
Response 3: Thank you for the review. The threshing drum consists of 3 millimeters symmetric rasp bar as shown in figure 4. Some of the rasp bars, top covers, and bottom covers are suppressed on the CAD modal to clearly illustrate the shaft, bushing, and drum.
Point 4: The authors mentioned “The mode shapes of the bracket are shown in figure 7.” in line 181. This is obviously wrong. The authors need to provide the correct modal calculations for the bracket.
Response 4: Thank you for the suggestion. The modal frequencies are updated in the manuscript. Additionally, the modal frequencies of the threshing drum are calculated and presented in an improved manuscript (Figure 7).
Point 5: It is better to improve the quality of all figures in this manuscript.
Response 5: Thank you for the suggestion. Some figures are improved on the manuscript (Figure 2, Figure 7. Figure 8, Figure 9, Figure 20. Figure A7, Figure A8, and Figure A9).
Point 6: Where did the random input PSD load spectrum (Table 8) come from? Is it measured experimentally? It is not clearly explained in the paper.
Response 6: The PSD value (Table 8) are random for frequencies ranging from 10-2,000 Hz. As the measured Input PSD value has a lower amplitude (g2/Hz). We are interested to know the response of the PSD for random amplitude with higher amplitudes to study the response behavior. The explanation is added in the manuscript (Lines 380-381).
Point 7: The grammatical and spelling errors should be carefully corrected in the revision.
Response 7: Thank you for the suggestion. The grammatical and spelling errors are carefully corrected in the revision.
Point 8: Figure 2, the sensor installation diagram in the left figure is not clear, and recommended to be modified. Whether all the accelerometers need to be installed as shown in Figure 2, this paper needs further explanation.
Response 8: Thank you for the suggestion. The description of the picture is added to the text. The first figure represents the angle of the accelerometer mounted and the second figure represents the position of the sensor mounted (Lines 116-118).
Point 9: The composition and working principle of the bench need further explanation as shown in Figure 3. Tangential Threshing unit bearing test bench and Figure 3 should make the reader clear about the composition and working principle of the vibration test platform.
Response 9: Thank you for the review. The composition and the working principle of the threshing tangential test stand are added to the manuscript (Lines 157-154).
Point 10: Figure 18 appears repeatedly in this paper, and is recommended to be simplified. The other pictures need further modification and standardization, such as figure 20.
Response 10: Thank you for the review. A similar figure is eliminated.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
No more suggestions
