Prosecution Insights
Last updated: April 19, 2026
Application No. 18/110,442

BARRIER COATING FOR AN ELECTRIC MOTOR ROTOR ASSEMBLY

Final Rejection §103§112
Filed
Feb 16, 2023
Examiner
KENERLY, TERRANCE L
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
BORGWARNER, INC.
OA Round
4 (Final)
73%
Grant Probability
Favorable
5-6
OA Rounds
2y 8m
To Grant
88%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
828 granted / 1129 resolved
+5.3% vs TC avg
Strong +15% interview lift
Without
With
+15.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
33 currently pending
Career history
1162
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
55.7%
+15.7% vs TC avg
§102
28.8%
-11.2% vs TC avg
§112
11.2%
-28.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1129 resolved cases

Office Action

§103 §112
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Response to Arguments Applicant’s arguments with respect to new claim(s) 20-32 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Specifically, since independent claim 20 changes the scope slightly of any previously filed device claim new references Stuart et al. and Sugiura et al. and Swec have been applied appropriately to claims 21-26. Regarding claim 27, The scope of any previously filed method claim has been changed slightly and new references Stuart et al. and Sugiura et al. and Swec have been applied appropriately to claims 28-32 as well. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 27-32 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Regarding claim 27, it is unclear where/what the permanent magnets are coupled to. This makes the metes and bounds of the claim indefinite because of the need to know where the magnets are coupled in/on the rotor assembly. Claims 28-32 depend from claim 27 and are likewise rejected. For examining purposes, the limitations of claim 27 will be construed as being taught by the prior art. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claim(s) 20, 21, 25-28 & 32 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuart et al. (US 6655004) in view of Sugiura et al. (WO 2020209051). 20. Stuart et al. teach: A rotor assembly 10 configured to be used by an electric motor (col 1 paras 2-6), comprising: an output shaft 14; a permanent magnet assembly 20 that includes one or more permanent magnets 20 coupled with the output shaft to prevent angular displacement of the permanent magnet(s) relative to the output shaft (figs 1-3); one or more composite sleeves 12 positioned concentrically and radially outwardly relative to the permanent magnet assembly (fig 1); but does not teach that a barrier coating, applied to an axial surface spaced from the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) forming a conformal coating that seals the permanent magnet assembly and the composite sleeve, providing a fluid-tight seal that prevents contact between the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) with an ambient environment. PNG media_image1.png 691 578 media_image1.png Greyscale Sugiura et al. teach that a barrier coating 50, applied to an axial surface spaced from the permanent magnet assembly (figs 6a-6c), axial outer surfaces of the composite sleeve(s) 43 (of Stuart et al., see Sugiura et al. figs 6a-6c), and radial outer surfaces of the composite sleeve(s) 43 (of Stuart et al., see Sugiura et al. figs 6a-6c) forming a conformal coating (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c) that seals the permanent magnet assembly and the composite sleeve (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c), providing a fluid-tight seal that prevents contact between the permanent magnet assembly, axial outer surfaces of the composite sleeve(s) (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c), and radial outer surfaces of the composite sleeve(s) with an ambient environment (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c) to reliably suppress distortion of the permanent magnets and protect them from damage. PNG media_image2.png 696 607 media_image2.png Greyscale As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that a barrier coating, applied to an axial surface spaced from the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) forming a conformal coating that seals the permanent magnet assembly and the composite sleeve, providing a fluid-tight seal that prevents contact between the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) with an ambient environment, as taught by Sugiura et al. so as to reliably suppress distortion of the permanent magnets and protect them from damage. 21. Stuart et al. in view of Sugiura et al. teach: The rotor assembly of claim 20, wherein the barrier coating (of Sugiura et al.) extends from the radial outer surface of the composite sleeve(s) to the output shaft 31 (the sleeve 31 is being interpreted as a shaft since it is made of steel). 25. Stuart et al. in view of Sugiura et al. teach: The rotor assembly of claim 20, further comprising a stator including a plurality of windings (excerpt below). PNG media_image3.png 172 618 media_image3.png Greyscale 26. Stuart et al. in view of Sugiura et al. teach: The rotor assembly of claim 20, wherein the axial surface spaced from the permanent magnet assembly is a surface of an end ring 35/41 that is positioned on the output shaft (figs 2 & 6a-6c). 27. Stuart et al. teach: A method of manufacturing a rotor assembly 10, configured to be used by an electric motor (col 1 paras 2-6), comprising the steps of: (a) coupling a permanent magnet assembly 20 that includes one or more permanent magnets; (b) assembling one or more composite sleeves 12 positioned concentrically and radially outwardly relative to the permanent magnet assembly; but does not teach that step of (c) applying a barrier coating to an axial surface spaced from the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) forming a conformal coating that seals the permanent magnet assembly and the composite sleeve, providing a fluid-tight seal that prevents contact between the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) with an ambient environment. Sugiura et al. teach the step of (c) applying a barrier coating 50 to an axial surface spaced from the permanent magnet assembly , axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) forming a conformal coating (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c) that seals the permanent magnet assembly and the composite sleeve (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c), providing a fluid-tight seal that prevents contact between the permanent magnet assembly, (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c) axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) with an ambient environment (since the resin portion covers all surfaces of the sleeve 43 and magnet 37, see Sugiura et al. figs 6a-6c) to reliably suppress distortion of the permanent magnets and protect them from damage. As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it with the step of (c) applying a barrier coating to an axial surface spaced from the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) forming a conformal coating that seals the permanent magnet assembly and the composite sleeve, providing a fluid-tight seal that prevents contact between the permanent magnet assembly, axial outer surfaces of the composite sleeve(s), and radial outer surfaces of the composite sleeve(s) with an ambient environment., as taught by Sugiura et al. so as to reliably suppress distortion of the permanent magnets and protect them from damage. 28. Stuart et al. in view of Sugiura et al. teach: The method of claim 27, wherein the barrier coating (of Sugiura et al.) extends from the radial outer surface of the composite sleeve(s) to the output shaft (the sleeve 31 is being interpreted as a shaft since it is made of steel). 32. Stuart et al. in view of Sugiura et al. teach: The method of claim 27, wherein the axial surface spaced from the permanent magnet assembly is a surface of an end ring 35/41 that is positioned on the output shaft (figs 2 & 6a-6c). Claim(s) 22 and 29 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuart et al. in view of Sugiura et al. and in further view of Eckberg. 22. Stuart et al. in view of Sugiura et al. have been discussed above, re claim 21 above; but does not teach that the barrier coating comprises a powder coating. Eckberg et al. teach that the step of applying a barrier coating, in the form of a conformal coating initially atomized before application (since a powder coating 52 is applied between the magnets46 and sleeve 56) on a radially inner side of the sleeve acts as a barrier and seal which prologs the life of the rotor. Thus, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that the barrier coating comprises a powder coating, as taught by Eckberg et al so as to prolong the life of the motor. 29. Stuart et al. in view of Sugiura et al. have been discussed above, re claim 28 above; but does not teach that the barrier coating comprises a powder coating. Eckberg et al. teach that the step of applying a barrier coating, in the form of a conformal coating initially atomized before application (since a powder coating 52 is applied between the magnets46 and sleeve 56) on a radially inner side of the sleeve acts as a barrier and seal which prologs the life of the rotor. Thus, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that the barrier coating comprises a powder coating, as taught by Eckberg et al so as to prolong the life of the motor. Claim(s) 23 and 30 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuart et al. in view of Sugiura et al. and Eckberg and in further view of Iizuka et al. (US 20190345956). 23. Stuart et al. in view of Sugiura et al. and Eckberg et al. have been discussed above, re claim 22; but do not teach that the output shaft is a turbine shaft for an electrically-assisted turbocharger. Iizuka et al. teach that the output shaft 9 is a turbine shaft 9 for an electrically-assisted turbocharger 1. By having the motor of Stuart et al. in the turbo-charger of Iizuka et al., the versatility of Stuart et al. motor would be improved and/or the turbocharger of Iizuka et al. would have the benefits of Stuart et al. motor. As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that the output shaft is a turbine shaft for an electrically-assisted turbocharger, as taught by Iizuka et al. so as to improve the versatility of the motor. 30. Stuart et al. in view of Sugiura et al. and Eckberg et al. have been discussed above, re claim 29; but do not teach that the output shaft is a turbine shaft for an electrically-assisted turbocharger. Iizuka et al. teach that the output shaft 9 is a turbine shaft 9 for an electrically-assisted turbocharger 1. By having the motor of Stuart et al. in the turbo-charger of Iizuka et al., the versatility of Stuart et al. motor would be improved and/or the turbocharger of Iizuka et al. would have the benefits of Stuart et al. motor. As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that the output shaft is a turbine shaft for an electrically-assisted turbocharger, as taught by Iizuka et al. so as to improve the versatility of the motor. Claim(s) 24 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuart et al. in view of Sugiura et al. and in further view of Iizuka et al.. 24. Stuart et al. in view of Sugiura et al. have been discussed above, re claim 20; but do not teach that the output shaft is a turbine shaft for an electrically-assisted turbocharger. Iizuka et al. teach that the output shaft 9 is a turbine shaft 9 for an electrically-assisted turbocharger 1. By having the motor of Stuart et al. in the turbo-charger of Iizuka et al., the versatility of Stuart et al. motor would be improved and/or the turbocharger of Iizuka et al. would have the benefits of Stuart et al. motor. As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that the output shaft is a turbine shaft for an electrically-assisted turbocharger, as taught by Iizuka et al. so as to improve the versatility of the motor. Claim(s) 31 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stuart et al. in view of Sugiura et al. and in further view of Swec (US 20050134137). 31. Stuart et al. in view of Sugiura et al. have been discussed above, re claim 27; but do not teach that the barrier coating is applied by immersing the rotor assembly in a bath of material. Swec teaches that the barrier coating is applied by immersing the rotor assembly 300 in a bath of material (see para 0058 1st sentence). This new method of applying the barrier coating makes the barrier coating more versatile as compared to only being applied by one method As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention of Stuart et al. being effectively filed to modify it such that the barrier coating is applied by immersing the rotor assembly in a bath of material, as taught by Iizuka et al. so as to improve the versatility of the barrier coating. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to TERRANCE L KENERLY whose telephone number is (571)270-7851. The examiner can normally be reached M-F 9am-5pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Christopher Koehler can be reached at 5712723560. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /TERRANCE L KENERLY/Primary Examiner, Art Unit 2834
Read full office action

Prosecution Timeline

Feb 16, 2023
Application Filed
Dec 06, 2024
Non-Final Rejection — §103, §112
Mar 03, 2025
Response Filed
Mar 20, 2025
Final Rejection — §103, §112
Jun 12, 2025
Interview Requested
Jun 20, 2025
Applicant Interview (Telephonic)
Jun 20, 2025
Examiner Interview Summary
Aug 21, 2025
Request for Continued Examination
Aug 25, 2025
Response after Non-Final Action
Sep 04, 2025
Non-Final Rejection — §103, §112
Dec 03, 2025
Response Filed
Mar 06, 2026
Final Rejection — §103, §112 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
73%
Grant Probability
88%
With Interview (+15.1%)
2y 8m
Median Time to Grant
High
PTA Risk
Based on 1129 resolved cases by this examiner. Grant probability derived from career allow rate.

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