Rolling Bearing Precision Grinding Patent Landscape 2026
Rolling bearing precision grinding is a mature, concentrated field dominated by Japanese and European bearing specialists, with NSK and NTN holding the top two positions among 172 patent families in scope. Filing activity peaked in 2018 and has eased since, signaling that the core technology space has passed its primary growth phase while adjacent process branches remain comparatively sparse.
NSK and NTN lead a tightly held field with SKF close behind
NSK Ltd and NTN Corp occupy the top two positions with 91 and 90 patent records respectively, followed closely by AB SKF at 62. These three alone account for the bulk of activity among the top hundred filers, establishing a clear first tier of established bearing manufacturers.
The top five filers — NSK, NTN, AB SKF, Schaeffler Technologies, and JTEKT — collectively hold 58% of the hundred largest filers’ combined total, indicating a highly concentrated competitive structure. The gap between the top three and the rest of the ranking is substantial, with Schaeffler at 27 patent records and JTEKT at 23 marking the start of a distinct second tier.
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 1 | NSK Ltd | 91 | |
| 2 | NTN Corporation | 90 | |
| 3 | AB SKF | 62 | |
| 4 | SCHAEFFLER TECHNOLOGIES AG & CO KG | 27 | |
| 5 | JTEKT Corporation | 23 | |
| 6 | Koyo Seiko Co. Ltd | 21 | |
| 7 | The Torrington Company | 9 | |
| 8 | National Engineering Industries Ltd | 6 | |
| 9 | Delphi Technologies Inc | 6 | |
| 10 | Nakayama Steel Works Ltd | 5 |
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 11 | Sumitomo Electric Sintered Alloy Ltd | 5 | |
| 12 | Harmonic Drive Systems Inc | 5 | |
| 13 | AVIC Harbin Bearing Co. Ltd | 5 | |
| 14 | Luoyang LYC Bearing Co. Ltd | 4 | |
| 15 | SKF ENG & RES CENT | 4 | |
| 16 | Osaka Seiki Co. Ltd | 4 | |
| 17 | SKF Aerospace France SAS | 4 | |
| 18 | ORTADOGU RULMAN SANAYI & TICARET ANONIM SIRKETI | 3 | |
| 19 | Xinxiang Yiwei CNC Machine Tool Co. Ltd | 3 | |
| 20 | Dalian Metallurgical Bearing Co. Ltd | 3 |
The leaders’ positions reflect decades of cumulative investment in bearing geometry, raceway surface finishing, and material science. New entrants seeking freedom to operate face a dense prior-art landscape in core F16C and B24B branches, making differentiation through adjacent process or materials routes more tractable than direct competition in established grinding methods.
Patent publication typically lags filing by 18–24 months, so figures for 2025 and 2026 undercount actual recent activity and should not be read as the final tally for those years. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
A 2018 peak followed by easing volume; bearing geometry dominates the technology mix
The annual filing trend and IPC class composition together reveal a field in late-stage consolidation: activity surged to a 2018 peak of 37 records before declining, while the technology mix remains anchored in core bearing and grinding classes with scattered coverage of adjacent process routes.
Annual filing trend
Filings reached a clear peak of 37 records in 2018, then fell sharply to 8 in 2020 before a partial recovery to 24 in 2021. Since 2021 the annual count has trended lower — 14 in 2022, 12 in 2023, and 11 in 2024. The 2025 and 2026 figures are subject to publication lag and will rise as pending applications publish; the apparent low counts for those years should not be interpreted as a sustained further decline.
↗ Hover for values · click a bar to ask EurekaTechnology composition
F16C (Shafts, Bearings & Couplings) dominates with 426 records, reflecting the core bearing design focus of the field. B24B (Grinding & Polishing) is the second-largest branch at 163 records, directly capturing precision surface finishing methods. C21D (Heat Treatment), B23P (General Metal Working), C23C (Coating & Surface Deposition), and C22C (Alloys) each appear at much lower counts, indicating that thermal, coating, and materials-science approaches are comparatively underrepresented relative to the dominant bearing and grinding classes.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Method and apparatus for superfinishing tapered ro…
A superfinishing method of a tapered roller bearing, including the steps of: rotating an outer ring of the tapered roller bearing about a center axis thereof; inserting a straight-shaped superfinishing stone from a front face of outer ring; and slidingly contacting a leading end face of the superfinishing stone with a taper-shaped raceway surface formed in… (excerpt from the patent abstract)
| # | Patent | Citations |
|---|---|---|
| 1 | Bearing surfaces with isotropic finish | 81 |
| 2 | Rolling bearings | 57 |
| 3 | Method of and machine for grinding a workpiece | 56 |
| 4 | Rolling bearing | 40 |
| 5 | Cold formed high-loaded bearing steel parts and pr… | 37 |
| 6 | Track roller bearing floating sleeve system | 37 |
| 7 | Bearing wheel assembly | 35 |
| 8 | Asymmetric angular contact ball bearing | 33 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the landscape structure means for R&D investment decisions
Concentration, lifecycle stage, and technology mix each carry distinct implications for teams evaluating entry points, partnership targets, or freedom-to-operate in rolling bearing precision grinding.
Field is in decline from a 2018 peak
Annual filing volume peaked at 37 records in 2018 and has eased substantially since. The lifecycle stage is characterized as Decline, with a recent-window growth rate of –33%. R&D teams should treat the core grinding and bearing geometry space as largely claimed and focus new filings on differentiated sub-processes or emerging adjacent branches rather than the crowded central claims.
Lifecycle: DeclineTop five control 58% of the leading-filer pool
NSK, NTN, AB SKF, Schaeffler Technologies, and JTEKT collectively hold 58% of the top hundred filers’ combined total. This degree of concentration means that licensing, partnership, or acquisition approaches targeting these five incumbents could access the majority of relevant prior art. New entrants with fewer than 10 patent records — such as NAT ENG IND, Delphi Technologies, and Nakayama Steel Works — occupy a distant third tier with limited blocking power.
High concentrationNTN–NTN Toyo and Koyo–Nakayama are the most active co-filers
The most active co-filing pair is NTN and NTN Toyo Bearing Co. Ltd with 6 joint records, followed by Koyo Seiko and Nakayama Steel Works at 5, and SKF with SKF Aerospace France at 4. NSK has filed jointly with Mizuho Ika Kogyo (3 records) and with Toyota Motor Corporation (2 records through Koyo Seiko). These pairings suggest that collaboration within corporate families and with specialist steel or aerospace partners is the dominant co-development pattern, rather than cross-industry open innovation.
Intra-group co-filing dominantUS leads filings; China and EPO are the next most-targeted jurisdictions
The United States is the leading jurisdiction with 139 patent records, ahead of China at 98, EPO at 92, and Japan at 86. The UK at 36 records reflects historic European manufacturing clusters. WIPO PCT filings at 20 indicate moderate international prosecution activity. China’s position at second reflects both domestic manufacturers such as AVIC Harbin Bearing and Luoyang LYC Bearing entering the space and incumbents seeking Chinese protection for their portfolios.
US-led; China risingGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| NTN Corporation | NTN Toyo Bearing Co. Ltd | 6 |
| Koyo Seiko Co. Ltd | Nakayama Steel Works Ltd | 5 |
| AB SKF | SKF Aerospace France SAS | 4 |
| NSK Ltd | Mizuho Ika Kogyo Co. Ltd | 3 |
| Koyo Seiko Co. Ltd | Toyota Motor Corporation | 2 |
| Koyo Seiko Co. Ltd | Mitsubishi Heavy Industries Ltd | 2 |
| NTN Corporation | Shinto Preda Co. Ltd | 1 |
| NSK Ltd | Ochi Takao (individual) | 1 |
| NSK Ltd | Mino Takayoshi (individual) | 1 |
| NSK Ltd | Tech Mizuho Co. Ltd | 1 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
NSK and NTN lead on volume; SKF is accelerating as a new entrant in the recent window
The top three players share a common anchor in F16C bearing design but diverge in their secondary technical emphasis — NSK and NTN concentrate on raceway geometry, while SKF extends into general metal working and surface engineering. Recent momentum data reveals sharply different trajectories within this leading group.
NSK Ltd
NSK holds 91 patent records, the largest count in the ranking. Its technology emphasis is concentrated in F16C 33 (74 records under NSK’s Japanese entity) and F16C 19 (24 records), with a secondary position in B24B 35 grinding and polishing (20 records), making it the most balanced across both bearing design and precision grinding process claims. Recent momentum shows a strong uptick, with NSK classified as a new entrant in the most recent filing window — suggesting a renewed filing push after a quieter period.
patent records: 91AB SKF
AB SKF holds 62 patent records, third in the ranking behind NTN Corp at 90. SKF’s technology focus sits in F16C 33 (56 records) and F16C 19 (15 records), with a notable secondary cluster in B23P 9 general metal working (12 records) — a differentiated emphasis compared to the top two. SKF is also classified as a new entrant in the most recent filing window, indicating fresh prosecution activity. Its co-filing relationship with SKF Aerospace France (4 joint records) extends its reach into aerospace-grade bearing applications.
patent records: 62| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| NTN Corporation | 1 | ▼ -95% |
| NSK Ltd | 6 | ▲ new entrant |
| AB SKF | 7 | ▲ new entrant |
Heat treatment and coating branches are under-served relative to the core grinding focus
Several IPC branches appear at comparatively low counts relative to F16C and B24B, suggesting that certain process and materials routes are sparsely filed. Whether any of these represent genuine entry opportunities depends on technical fit and commercial context.
C21D · Heat Treatment of Metals
C21D accounts for 43 patent records — roughly one-tenth the volume of the dominant F16C class. Heat treatment is technically integral to bearing precision grinding: surface hardness and residual stress profiles from quenching and tempering directly affect achievable grinding tolerances and fatigue life. The sparse filing density relative to the grinding process itself suggests that thermal process optimization for precision-ground bearing surfaces is an under-documented area. Teams with process expertise in carburizing, induction hardening, or sub-zero treatment cycles could explore filings here, particularly as tighter bearing tolerances for EV and wind turbine applications demand tighter thermal process control.
Search this in Eureka →C23C · Coating & Surface Deposition
C23C (Coating & Surface Deposition) carries 29 patent records, representing approximately 3% of the IPC distribution in this corpus. Functional coatings — such as DLC (diamond-like carbon), PVD nitride layers, or anti-fretting films — applied to precision-ground bearing raceways are a growing area of technical interest for extending service life in contaminated or lubrication-starved environments. The low filing count relative to the broader bearing and grinding classes indicates that the intersection of post-grinding coating processes and bearing performance is sparsely claimed. Entry here would require demonstrating that coating deposition is specifically adapted to the ground surface finish rather than generic substrate coating, but the competitive density appears lower than in the core grinding classes.
Search this in Eureka →How leaders differ across bearing design, grinding process, and materials routes
Route coverage across the main technology branches in the current evidence set.
| Player | F16C 33 · Shafts, bearings & couplings | F16C 19 · Shafts, bearings & couplings | B24B 19 · Grinding & polishing | B24B 35 · Grinding & polishing | B24B 41 · Grinding & polishing |
|---|---|---|---|---|---|
| NTN Corporation | Strong · 84 | Strong · 70 | Emerging · 4 | Emerging · 4 | Absent |
| NSK Ltd | Strong · 74 | Moderate · 24 | Moderate · 17 | Moderate · 20 | Absent |
| AB SKF | Strong · 56 | Moderate · 15 | Absent | Absent | Absent |
| Koyo Seiko Co. Ltd | Strong · 26 | Moderate · 13 | Emerging · 4 | Emerging · 4 | Absent |
| Schaeffler AG | Strong · 16 | Strong · 10 | Absent | Absent | Absent |
| Schaeffler Technologies AG & Co. KG | Strong · 11 | Strong · 8 | Moderate · 4 | Absent | Absent |
| JTEKT Corporation | Strong · 11 | Strong · 7 | Absent | Absent | Absent |
Frequently asked questions
The analysis covers 172 patent families in scope. The top-100 applicant ranking is measured in patent records, which can exceed the family count because a single family may generate multiple national records.
NSK Ltd leads with 91 patent records, followed by NTN Corp at 90 and AB SKF at 62. Schaeffler Technologies and JTEKT Corp occupy a clear second tier at 27 and 23 records respectively. These five together account for 58% of the top hundred filers’ combined total.
No. The lifecycle stage is characterized as Decline. Annual filings peaked at 37 records in 2018 and have eased substantially since, with the recent three-year window showing a -33% growth rate. The 2025 and 2026 data are subject to publication lag and will revise upward as pending applications publish, but the structural downtrend from the 2018 peak is evident.
The United States leads with 139 patent records at the jurisdiction level, followed by China at 98, EPO at 92, and Japan at 86. The UK at 36 records and WIPO PCT at 20 round out the major filing routes. These counts are at the patent-record level and reflect where applicants have sought protection, not the number of unique inventions in each territory.
The most-cited work covers bearing surfaces with isotropic finish (81 citations), rolling bearings (57 citations), a method and machine for grinding a workpiece (56 citations), and cold-formed high-loaded bearing steel parts (37 citations). These highly cited references define the core prior-art landscape that any new filing must navigate.
C21D (Heat Treatment of Metals) at 43 records and C23C (Coating & Surface Deposition) at 29 records are the most technically adjacent branches with relatively low filing density compared to the dominant F16C and B24B classes. B23P (General Metal Working) at 42 records and C22C (Alloys) at 23 records are also comparatively sparse. These observations do not automatically constitute open opportunities — technical fit and freedom-to-operate analysis are required before drawing investment conclusions.
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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.