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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/harmonic-drive-interface-engineering-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Patent Landscape · Mechanical Engineering & MachineryHarmonic Drive Interface Engineering Patent Landscape 2026
- Filing has cooled since 2021. 47 filings peaked that year against 22 in 2017; the 2022 midpoint of 26 shows the field has flattened rather than kept climbing.
- F16H owns every record by design of the search, but the interface spills outward. H02K (42), F16C (37) and B25J (29) show tooth-contact work is increasingly filed alongside motor, bearing and robot-arm claims, not in isolation.
- Co-assignment is rare and thin. Only 10 co-assignee pairs exist across 497 families, and the strongest link is a single five-record pairing — this is a field of solo filers, not joint ventures.
497
Published Records
28%
Top-5 Share of All Records
-51%
Filing Growth 2021→2024
US
Leading Jurisdiction
Filing growth compares 2021 (47 records) with 2024 (23) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 497 records in scope (CR5), not by the ranked leaders only.
Published byPatsnap Research··7 min readSourced from Patsnap Eureka
Overview
What this landscape covers
Harmonic drive interface engineering is the narrow but consequential slice of strain wave gearing that governs how a flexspline and a rigid circular spline actually stay in contact: tooth profile, meshing stiffness and the geometry that avoids interference as the wave generator sweeps the flexspline through its cycle. The search here is deliberately tight — title/abstract mentions of harmonic drive, strain wave gear or harmonic reducer, cross-referenced against tooth contact, meshing stiffness, flexspline or tooth profile in the title, claims or description, under F16H49 or F16H55/08. That precision is why every one of the 497 families carries an F16H classification; the interesting movement is in the secondary classes riding alongside it.
497 families published between 2015 and the mid-2026 cut-off give a workable, if compact, view of the field. Publication lags filing by roughly 18 months, so 2025 and 2026 are undercounted here and should be read as a floor, not a ceiling.
Filing activity, 2017–2026
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
The data
Filing trend and technology composition
Two views of the same 497 families: how filing has moved year over year, and which adjacent IPC subclasses the interface-engineering claims are drafted alongside.
A field that peaked in 2021 and has not recovered
Filings ran from 22 in 2017 to a high of 47 in 2021, then eased back toward the 2022 midpoint of 26. Read against the publication lag, the 2025-2026 tail is not yet a reliable signal of decline, but the shape from 2017 through 2022 is a genuine plateau rather than sustained growth.
F16H anchors the search; the spillover classes tell the real story
All 497 records sit in F16H by construction of the search string. Beyond that, H02K (electric motors, 42 records), F16C (bearings and couplings, 37) and B25J (manipulators and robots, 29) are where interface claims most often get drafted alongside adjacent hardware, followed by B62M, F16D, G06F and G01L in smaller counts — evidence that flexspline and tooth-contact work is increasingly claimed as part of a motor-gearbox-arm assembly rather than as a standalone reducer.
Shares are the percentage of the 497 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Source: Patsnap Eureka. Filing trend and technology composition. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
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The cited backbone of the field
Representative record
Tooth profile arrangement to eliminate tooth interference in extended contact harmonic drive devices
TEIJIU SEIKI BOSTON, INC.
The present invention comprises an extended tooth contact harmonic drive gearing apparatus for transmitting rotary motion from an input drive to an output drive through mating contact between a flexspline and a rigid circular spline, the flexspline being swept into a non-circular shape by a wave generator. The wave generator causes the teeth of the flexspline to precess from a normal to an inclined orientation and back to a normal orientation again. The teeth on both the flexspline and the circular spline have a profile which accomodates that tooth inclination, and thus avoids interference therebetween.US5456139A, filed by Teijiu Seiki Boston, Inc., granted 1995-10-10 — the priority art underlying much of the extended-tooth-contact profile work that followed.
Most-cited records in this corpus
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5269202A | Cup-type harmonic drive having a short, flexible cup member | 121 |
| 2 | US4823638A | Tooth profile of spline of strain wave gearing | 103 |
| 3 | US3986412A | Redundant motor reducer drive | 98 |
| 4 | US4974470A | Tooth profile of one of circular splines of flat-shaped strain wave gearing | 88 |
| 5 | US6258007B1 | Multi-sensor harmonic drive actuator arrangement assembly | 84 |
| 6 | US3789700A | Positive drive roller planetary wave generator | 76 |
| 7 | US4909098A | Harmonic drive apparatus | 66 |
| 8 | US4715247A | Transmission apparatus with reduced frictional force | 63 |
| 9 | US6026711A | Harmonic drive bearing arrangement | 58 |
| 10 | US3996816A | Harmonic drives | 56 |
Citation counts inside this searched corpus favour older filings; treat the ranking as a map of influence on later drafting, not a guide to what matters today.
Each row carries its publication number; clicking a row searches Eureka by that number.
Source: Patsnap Eureka. Citation counts and representative records. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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What the numbers mean for a filing decision
Three readings of the same dataset, aimed at where to file and where not to.
Filing pace
47 → 26
2021 peak vs 2022 midpoint
Growth has flattened, not accelerated
The run from 22 filings in 2017 to a 2021 peak of 47 looked like sustained growth; the drop back to 26 by 2022 shows it was a cycle, not a trend. New entrants should treat the interface-engineering core as occupied claim space rather than an open growth curve.
Filing trend, 2017-2022
Jurisdiction
139 US · 109 EP
Leading receiving offices
US and Europe carry the bulk of filing activity
United States (139) and the EPO (109) lead receiving offices, with China (60) and WIPO/PCT (60) roughly level behind them. Canada (24) and Japan (15) trail — a smaller footprint in Japan than the technology's origins might suggest.
Receiving office counts
Collaboration
10 pairs
Co-assignee pairs across 497 families
Almost no joint filing
Only 10 co-assignee pairs appear across the entire corpus, and the strongest is a five-record pairing between two assignees. This is overwhelmingly a field of single-assignee filing; cross-licensing or joint-development signals are weak to absent.
Co-assignee pair count
Eureka AI Agent
Looking for what nobody has claimed yet?
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to harmonic drive interface engineering, with the prior art for and against each one.
Collaboration is the exception, not the rule
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Teijin Seiki Boston, Inc. | USM Corporation | 5 |
| Harmonic Drive Systems Inc. | MENDEL MATTHIAS | 3 |
| Harmonic Drive Systems Inc. | Harmonic Drive Co., Ltd. | 2 |
| Harmonic Drive Systems Inc. | ZENS FRANK | 2 |
| Harmonic Drive Systems Inc. | SCHULZE CARSTEN | 2 |
| Teijin Seiki Boston, Inc. | NEW CONNECTICUT BANK & TRUST CO NAT ASSOC THE | 2 |
| Nexen Group, Inc. | KLIBER ANTHONY WILL | 2 |
| Nexen Group, Inc. | BOUSHEK CHARLES CHRISTIAN | 2 |
With only 10 co-assignee pairs across 497 families, most interface-engineering IP is built and held by one organisation at a time — useful context when assessing freedom-to-operate around any single filer.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Players
Who holds the claims, and where activity has stalled
Recent-year momentum reads flat across the named assignees below — every one shows zero filings in the latest year, and several show a full year-over-year drop from their prior level. That is consistent with the 2021 peak-and-plateau pattern in the trend data, not with any single company pulling back.
Momentum
0 latest year
Harmonic Drive Systems Inc.
Leading filer, currently quiet
Harmonic Drive Systems Inc. (Harmonic Drive Systems) shows the strongest co-assignee links in the dataset, including a two-record pairing with Harmonic Drive Co., Ltd., but no filings in the latest recorded year.
Co-assignee data
Momentum
-100% YoY
Ovalo GmbH
Full year-over-year drop
Ovalo GmbH moved to zero filings in the latest year, a complete drop from its prior level — one of two named assignees showing this pattern.
Recent-year momentum
Momentum
5 co-filed records
Teijin Seiki Boston, Inc. + USM Corporation
The strongest filing partnership on record
Teijin Seiki Boston, Inc. and USM Corporation form the densest co-assignee pair in the corpus at five shared records, well ahead of the next-strongest pairing.
Strongest co-assignee pair
Recent-year momentum by assignee
| Assignee | Recent year | YoY |
|---|---|---|
| Harmonic Drive Systems Inc. | 0 | — |
| Teijin Seiki Boston, Inc. | 0 | — |
| USM Corporation | 0 | — |
| Ovalo GmbH | 0 | -100% |
| Schaeffler Technologies AG & Co. KG | 0 | -100% |
| California Institute of Technology | 0 | — |
| Harmonic Drive Systems Ltd. | 0 | — |
| Nexen Group, Inc. | 0 | -100% |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
What's next
Where to take this
The dataset points to where the field is occupied and where it is thin. Two directions follow from that.
Map the interface against adjacent hardware classes
H02K, F16C and B25J together account for more secondary classifications than any pure-gearing subclass. A claim drafted purely against F16H risks missing the motor- or arm-integration prior art that increasingly frames this space.
Explore in Eureka →Test freedom-to-operate against the cited backbone
The five most-cited records, including the extended-tooth-contact patent detailed above, still anchor later drafting decades on. Any new tooth-profile or flexspline claim should be checked against that lineage before filing.
Run a citation check in Eureka →Source: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
FAQ
Common questions on this landscape
It refers to the claims that govern how the flexspline and the rigid circular spline of a strain wave gear actually make and maintain contact — tooth profile geometry, meshing stiffness, and the wave-generator motion that sweeps the flexspline through its elliptical cycle. In this dataset it is defined narrowly, by title/abstract mentions of harmonic drive, strain wave gear or harmonic reducer combined with tooth contact, meshing stiffness, flexspline or tooth profile terms, filtered to F16H49 or F16H55/08. That precision is why the field looks smaller than harmonic drives generally, but it isolates the mechanically hardest part of the design.
No, not on this evidence. Filings ran from 22 in 2017 to a peak of 47 in 2021, then eased to 26 by the 2022 midpoint, which is a plateau-and-decline shape rather than sustained growth. The most recent one to two years are undercounted because publication lags filing by roughly 18 months, so the true 2025-2026 picture will only firm up over the next reporting cycles. Treat the current trend as flat rather than as evidence of a shrinking field.
The dataset shows a concentrated set of named assignees, including Harmonic Drive Systems Inc. (Harmonic Drive Systems) and Teijin Seiki Boston, Inc. (Teijin Seiki Boston), rather than a single dominant filer. Co-assignment is rare — only 10 pairs across 497 families — so most patents are held by one organisation without a joint filing partner. Recent-year momentum across the named leaders is flat, with zero filings in the latest year for several of them, which is consistent with the broader plateau in the trend data rather than any one company's retreat.
The strongest overlaps are with H02K (electric motors and generators, 42 records), F16C (shafts, bearings and couplings, 37) and B25J (manipulators and robots, 29). Smaller but notable overlaps appear in B62M (cycle drives), F16D (clutches and brakes), G06F (digital data processing) and G01L (force and pressure measurement). This spread indicates that flexspline and tooth-contact claims are increasingly drafted as part of a motor-gearbox or robotic-joint assembly rather than filed as a standalone gearing invention.
US5456139A claims a tooth profile arrangement for extended-contact harmonic drive gearing that prevents tooth interference as the flexspline's teeth precess from normal to inclined orientation and back, under the sweep of the wave generator. It sits among the most-cited records identified in this corpus, which means later tooth-profile filings have repeatedly built on or distinguished themselves from it. Anyone drafting a new flexspline or circular-spline tooth-profile claim should check it directly, since its priority date and citation weight make it a likely reference point in any prior-art search.
Answers are grounded in the same dataset. Derived from a Patsnap search on Harmonic Drive Interface Engineering covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company's registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.