Bonded and Injection Molded Magnets Patents: Top Companies & Trends 2026
- 46.4% of all 2,702 records in scope sit with just five assignees — this is a concentrated field, not a fragmented one.
- Filings fell 69% from 2021 (67) to 2024 (21) the last three-year span with complete data, marking a real pullback from the 2021 peak.
- H01F appears in 85.1% of records but powder metallurgy (B22F, 34.2%) and alloy composition (C22C, 30.3%) carry a meaningful share of the claim activity underneath it.
Filing growth compares 2021 (67 records) with 2024 (21) — 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 2,702 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Bonded and injection molded magnets are built by binding magnetic powder — ferrite or rare-earth alloy — into a resin matrix, then compression-molding or injection-molding it into a net or near-net shape. The claim space spans alloy and powder composition, binder loading and dimensional tolerance, and multipole magnetization and thermal aging behaviour once the part is in service. This dataset covers 2,702 published records filed between 2015 and mid-2026, drawn from a search combining the process terms (bonded, injection molded, compression bonded magnet) with the technical qualifiers that distinguish real manufacturing claims from generic magnet filings.
Because publication trails filing by roughly 18 months, the most recent one to two years in any trend understate real activity — treat 2025 and 2026 figures as provisional rather than as evidence of a slowdown.
Filing trend and technology composition
Two views of the same 2,702 records: how filing activity has moved year over year, and which parts of the IPC scheme carry the claims.
Filing trend, 2017–2026
Filings ran from 51 in 2017 to a peak of 67 in 2021, then fell to 21 by 2024 — a 69% drop across that three-year span. 2025 and 2026 counts are still filling in and should not be read as continued decline.
IPC subclass composition
H01F (magnets, inductors and transformers) touches 85.1% of the 2,702 records, consistent with it being the core classification for the field. B22F (powder metallurgy, 34.2%) and C22C (alloys, 30.3%) are the next-heaviest classes, reflecting how much of the claim activity sits in powder and alloy formulation rather than in the finished magnet alone. Because records can carry multiple classes, these shares add up to more than 100% and should not be summed.
Shares are the percentage of the 2,702 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Bonded and Injection Molded Magnets with Eureka
This page is one run against one query. Ask Eureka your own question about bonded and injection molded magnets and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
US20050067052A1 — Alloy for use in bonded magnet, isotropic magnet powder and anisotropic magnet powder and method for production thereof, and bonded magnet
An alloy for bonded magnet alloy of the present invention includes at least Fe as a main component, 11-15 at % rare-earth element (R) that includes yttrium (Y) and does not include lanthanum (La), 5.5-10.8 at % B and 0.01-1.0 at % La, and has superior corrosion resistance. Using the obtained magnet powder by applying the d-HDDR process etc. to this bonded magnet, bonded magnet with not only magnetic properties but also reliability such as corrosion resistance and heat resistance etc., can be achieved.Filed by Honkura, Yoshimobu; published 2005-03-31. The claim ties a narrow rare-earth composition window to a specific production route (d-HDDR), which is the pattern most of the crowded claim space in this field follows.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5684352A | Permanent magnet field-type rotating machine | 280 |
| 2 | US20110057756A1 | Rare Earth Composite Magnets with Increased Resistivity | 120 |
| 3 | US20120091832A1 | Matrix material comprising magnetic particles for use in hybrid and electric vehicles | 115 |
| 4 | US20070034299A1 | Rare earth – iron – bron based magnet and method for production thereof | 102 |
| 5 | US20150170811A1 | Ferrite magnetic material, ferrite sintered magnet, and motor | 99 |
| 6 | JP2002093610A | Method of manufacturing anisotropic magnet powder, material powder of anisotropic magnet powder, and bonded m… | 98 |
| 7 | US6139766A | Oxide magnetic material, ferrite particles, sintered magnet, bonded magnet, magnetic recording medium, and mo… | 96 |
| 8 | US20110074231A1 | Hybrid and electic vehicles magetic field and electro magnetic field interactice systems | 92 |
| 9 | US20020097040A1 | Wheel rotation detecting device | 92 |
| 10 | US5049208A | Permanent magnets | 89 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside the corpus — read them as a signal of influence on the field, not of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Four read-outs from the concentration, class and geography figures above.
The top of the field is dense
Nearly half of all records in scope trace to just five assignees, and the top ten account for 60.2%. That is a strong signal that core compositions and manufacturing routes are already well staked out by a small group of Japanese electronics and metals firms.
Filing is anchored in Japan
Japan accounts for the largest share of receiving-office filings, well ahead of the United States (636) and Europe (501). China (86), WIPO (78) and Germany (72) trail by a wide margin, suggesting the commercial and defensive filing centre of gravity for this technology remains in Japan.
Powder and alloy claims underlie the magnet class
H01F covers the great majority of records, but a third of records also carry a powder-metallurgy classification and nearly a third an alloys classification. That overlap points to where the harder technical differentiation actually happens — in powder preparation and alloy chemistry, not the finished-magnet claim alone.
Activity has cooled from its 2021 peak
Filing volume dropped 69% between the 2021 peak and 2024, the last year with complete data. That decline sits alongside a group of established assignees showing zero filings in the latest year, consistent with a field where the core claim territory is already occupied rather than one still being actively built out.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to bonded and injection molded magnets, with the prior art for and against each one.
Leading assignees and where the gaps are
The ranked leaders in this dataset cover 100 companies. Filing is concentrated at the top, with a long tail of single- or low-volume filers behind them.
A clear leader, then a steep drop-off
The top-ranked assignee holds 412 records, more than double the fifth-place figure of 182, which itself is more than triple the tenth-place figure of 54. That curve — steep at the top, flattening fast — is typical of a field where a handful of vertically integrated electronics and metals manufacturers built the core IP position early.
Co-filing is concentrated in a few corporate families
Only 10 co-assignee pairs appear in the dataset, and the strongest pair alone accounts for 55 shared records. This looks like internal group filing — parent and subsidiary or affiliated manufacturing arms — rather than cross-company joint development, which is otherwise rare in this space.
Several established filers have gone quiet
A number of assignees with substantial historical filing counts show zero records in the latest year. Given the 18-month publication lag, some of that is an artefact of the data cut-off — but combined with the 2021-to-2024 volume drop, it points to a field where the largest players have slowed new filing rather than one where they have exited.
| Assignee | Recent year | YoY |
|---|---|---|
| Seiko Epson Corporation | 0 | — |
| Sumitomo Special Metals Co., Ltd. | 0 | — |
| TDK Corporation | 0 | — |
| Proterial, Ltd. | 0 | — |
| Aichi Steel Corporation | 0 | — |
| Panasonic Corporation (Japan) | 0 | — |
| Sumitomo Metal Mining Co., Ltd. | 0 | — |
| Suwa Seikosha Co., Ltd. | 0 | — |
Where to take this next
The figures above answer where the field stands. The next questions are usually specific to a claim, a competitor, or a filing decision.
Check freedom-to-operate on a specific composition
Alloy and powder claims dominate the crowded part of this field. Before filing a new composition claim, check it against the dense H01F/B22F/C22C overlap rather than against the magnet class alone.
Run a claim check in EurekaTrack a specific assignee's filing momentum
Several leading assignees show zero filings in the latest year, but the 18-month publication lag means that picture is incomplete. Watch the next two publication cycles before drawing conclusions about a competitor's exit.
Set up assignee tracking in EurekaExplore the under-claimed branches
Multipole magnetization tooling and thermal-aging flux stability carry fewer dedicated records than the core alloy classes. That is where a first-mover claim is more likely to clear.
Explore white space in EurekaCommon questions about this landscape
Filing in this field is concentrated: the top five assignees together hold 46.4% of the 2,702 records in scope, and the top ten hold 60.2%. The leading assignee alone accounts for 412 records, well ahead of the fifth-place figure of 182 and the tenth-place figure of 54. These are largely established Japanese electronics and specialty-metals manufacturers who built core alloy and powder positions early, so a newcomer should expect to file around, not through, that existing claim territory.
Filing peaked in 2021 at 67 records and fell to 21 by 2024, a drop of 69% over that three-year span — the most recent period for which the data can be treated as complete. Figures for 2025 and 2026 look lower still, but that is expected: publication typically lags filing by about 18 months, so the newest years always understate real activity. The honest read is a real pullback from the 2021 peak, not an ongoing collapse.
H01F, the class covering magnets, inductors and transformers, appears in 85.1% of the 2,702 records and is effectively the anchor classification for the field. Beneath it, B22F (powder metallurgy) appears in 34.2% of records and C22C (alloys) in 30.3%, showing that a large share of the technical differentiation happens in how the magnetic powder and alloy are prepared, not just in the finished-magnet design. Because a single record can carry several IPC codes, these shares add up to more than 100% and should be read individually, not summed.
Japan is by far the largest receiving office in this dataset with 1,002 filings, followed by the United States (636) and Europe via the EPO (501). China (86), the WIPO PCT route (78) and Germany (72) trail well behind. That distribution suggests the commercial and defensive filing priority for this technology has historically centred on Japan, with the US and Europe as the next-tier markets worth covering.
This filing, from Honkura, Yoshimobu, claims a bonded-magnet alloy built on an iron base with a specific rare-earth content window (11-15 at%, including yttrium but excluding lanthanum), boron content of 5.5-10.8 at%, and a small lanthanum addition of 0.01-1.0 at%, combined with a d-HDDR production process for improved corrosion and heat resistance. It blocks compositions that fall inside that exact elemental window when paired with that production route; alloys outside those ranges, or using a different powder-production process, are not directly covered. Anyone designing a similar rare-earth bonded-magnet alloy should check their composition against these specific atomic-percent ranges rather than assume the whole rare-earth-iron-boron space is blocked.
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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.