Prosecution Insights
Last updated: April 19, 2026
Application No. 18/282,563

Rotor Shaft Assembly for an Electric Machine and Electric Machine

Final Rejection §102§103
Filed
Sep 18, 2023
Examiner
STEFANON, JUSTIN
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT
OA Round
2 (Final)
51%
Grant Probability
Moderate
3-4
OA Rounds
3y 8m
To Grant
99%
With Interview

Examiner Intelligence

Grants 51% of resolved cases
51%
Career Allow Rate
94 granted / 183 resolved
-16.6% vs TC avg
Strong +48% interview lift
Without
With
+47.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 8m
Avg Prosecution
50 currently pending
Career history
233
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
34.1%
-5.9% vs TC avg
§102
38.4%
-1.6% vs TC avg
§112
25.2%
-14.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 183 resolved cases

Office Action

§102 §103
DETAILED ACTION 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, see page 5, section II, filed 11/14/2025, with respect to rejections under 35 USC 112 have been fully considered and are persuasive. The rejections under 35 USC 112 of claims 15-18 have been withdrawn. Applicant’s arguments with respect to 35 USC 102 rejections of claims 11-20 and 22 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. Applicant's arguments with respect to claim 21 filed 11/14/2025 have been fully considered but they are not persuasive. Claim 21 recites “an extended central slot axis oriented perpendicular to the rotation axis.” RONNING discloses an extended central slot axis oriented perpendicular to the rotation axis, as claimed. Claim Rejections - 35 USC § 102 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claims 11-14, 17-18 and 20-22 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by MICHAEL (US 20220060072, previously cited). Regarding claim 11, MICHAEL discloses a rotor shaft (1) assembly for an electric machine, the rotor shaft (1) assembly comprising: a hollow rotor shaft (1) comprising a rotational axis (11, 31) and configured to rotate about the rotational axis (11, 31) and to receive a rotor and delimit a cavity, which, in order to cool the rotor shaft (1), is configured to have a cooling medium flow therethrough; and a lance (3) which protrudes into the cavity and has an outflow region, via which the cooling medium which is conducted in the lance (3) can flow out of the lance (3) into the cavity, and in which the lance (3) comprises a swirling device, via which turbulence can be applied to the cooling medium during the flow out of the lance (3) (see para [0088]), wherein the lance (3) is stationary relative to the rotor shaft (1) such that the rotor shaft (1) rotates around and relative to the lance (3) (see para [0071]). PNG media_image1.png 288 500 media_image1.png Greyscale Regarding claim 12, MICHAEL discloses the rotor shaft assembly according to claim 11, wherein a gap exists between an outer pipe wall of the lance and an inner wall of the rotor shaft within the cavity of the hollow rotor shaft (see Fig. 1) wherein the lance (3) comprises, as the swirling device, at least one opening (32) which is arranged in the outer pipe wall of the lance (3) and via which the cooling medium can flow radially out of the lance (3) into the gap (see Fig. 1a and para. [0070]). PNG media_image2.png 264 456 media_image2.png Greyscale Regarding claim 13, MICHAEL discloses the rotor shaft assembly according to claim 12 wherein the at least one opening (32) is configured as a slot (see Fig. 1a and para. [0070]). Regarding claim 21, MICHAEL discloses the rotor shaft assembly according to claim 13 wherein the slot comprises an elongated geometry having an extended central slot axis oriented perpendicular to the rotational axis (see Fig. 1a). Regarding claim 14, MICHAEL discloses the rotor shaft assembly according to claim 12 wherein the at least one opening (32) is provided by way of a passage in the outer pipe wall, a center axis of which passage is oriented obliquely with respect to a center axis (31) of the lance (3) (32 is a conical bore; see Fig. 1a and para. [0070]). Regarding claim 17, MICHAEL discloses the rotor shaft assembly according to claim 12 wherein the lance comprises a free end that does not contact the inner wall or an end face of the rotor shaft (see Fig. 1a), and wherein at least two openings (44) are provided, which have an axial spacing of different length with respect to one another from the free end of the lance (3) (see Fig. 11a). PNG media_image3.png 225 388 media_image3.png Greyscale Regarding claim 18, MICHAEL discloses the rotor shaft assembly according to claim 12 wherein the lance comprises a free end that does not contact the inner wall or an end face of the rotor shaft (see Fig. 1a), and wherein the at least one opening (32) is provided by way of an incision in the pipe wall, the lance (3) being constricted at the free end by way of a pinched portion (the conical shape of the opening is a ‘pinched portion’ as broadly claimed; see Fig. 1a and para. [0070]). Regarding claim 20, MICHAEL discloses an electric machine comprising: a stator (S); a rotor (R); and a rotor shaft assembly (1) according to claim 11, wherein the rotor (R) is held on the hollow rotor shaft (1) (see para [0067] and Fig. 1). Regarding claim 22, MICHAEL discloses the rotor shaft assembly according to claim 11, wherein the lance is in the form of a pipe with a single internal passageway through which the cooling medium flows only in a direction toward the outflow region (see Fig. 1a). 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. Claims 15-16 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over MICHAEL in view of RONNING. Regarding claim 15, MICHAEL discloses the rotor shaft assembly according to claim 12 wherein the lance comprises a free end that does not contact the inner wall or an end face of the rotor shaft (see Fig. 1a), and wherein, in addition to the at least one opening (32) which is arranged in the outer pipe wall of the lance (3), at least one further outlet opening (44), via which the cooling medium can flow axially out of the lance (3) into the cavity to directly contact the inner wall of the rotor shaft (see Fig. 11a). However, MICHAEL does not disclose that the lance has the further outlet opening at the free end. RONNING discloses a rotor shaft assembly with a lance having further outlet openings at the free end (84) (see Fig. 2). PNG media_image4.png 713 590 media_image4.png Greyscale It 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 to provide the lance of MICHAEL with the further outlet openings at the free end, similar to RONNING. A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to further break up laminar flow, as taught by RONNING (see para [0044]). Regarding claim 16, MICHAEL in view of RONNING discloses the rotor shaft assembly according to claim 15 wherein MICHAEL discloses the at least one outlet opening (32) has a constricted cross section in comparison to a guide region of the lance (3) (see Fig. 1a), through which guide region the cooling medium is to be conducted within the lance (3) to the outflow region (see Fig. 1a). Regarding claim 19, MICHAEL discloses the rotor shaft assembly according to claim 11 wherein the swirling device is provided by way of a swirling element (4). However, MICHAEL does not disclose the swirling element is plugged into the lance. RONNING discloses a rotor shaft assembly with a lance and a swirling element (150) plugged into the lance (see Fig. 7). PNG media_image5.png 757 485 media_image5.png Greyscale It 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 to provide the lance of MICHAEL with swirling element(s), similar to RONNING. A person having ordinary skill in the art to which the claimed invention pertains would have been motivated to make such modification in order to permit design of a second flow passage to have any desired contouring or shape, as taught by RONNING (see para [0047]). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US-20210376685-A1 HACKLBERGER; US-20230264553-A1 LING disclose rotor cooling lances wherein a gap exists between an outer pipe wall of the lance and an inner wall of the rotor shaft within the cavity of the hollow rotor shaft. 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 JUSTIN STEFANON whose telephone number is (703)756-4648. The examiner can normally be reached Monday - Thursday and alternate Fridays 8AM - 5PM EDT. 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, Oluseye Iwarere can be reached at (571) 270-5112. 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. /JUSTIN STEFANON/Examiner, Art Unit 2834 /OLUSEYE IWARERE/Supervisory Patent Examiner, Art Unit 2834
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Prosecution Timeline

Sep 18, 2023
Application Filed
Jul 11, 2025
Non-Final Rejection — §102, §103
Nov 14, 2025
Response Filed
Jan 10, 2026
Final Rejection — §102, §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12494684
ROTOR OF AN ELECTRIC MACHINE
2y 5m to grant Granted Dec 09, 2025
Patent 12451742
METHOD AND APPARATUS FOR COOLING A ROTOR ASSEMBLY
2y 5m to grant Granted Oct 21, 2025
Patent 12316190
CASE STRUCTURE OF IN-WHEEL MOTOR
2y 5m to grant Granted May 27, 2025
Patent 9650015
BELT RETRACTOR FOR A VEHICLE SAFETY BELT
2y 5m to grant Granted May 16, 2017
Patent 9635986
SPINDLE AND ADAPTER FOR ROLL PAPER PRODUCT DISPENSERS
2y 5m to grant Granted May 02, 2017
Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
51%
Grant Probability
99%
With Interview (+47.7%)
3y 8m
Median Time to Grant
Moderate
PTA Risk
Based on 183 resolved cases by this examiner. Grant probability derived from career allow rate.

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