Hydraulic Valve Patents: Leaders, Trends & White Space 2026
- Filing has cooled since its 2021 peak. 39 families filed that year against just 2 in the partial 2026 count, with 2022's midpoint of 21 already signalling the decline — a mature, not a growing, filing environment.
- F15B and F16K dominate the classification mix. 704 and 500 records respectively, more than five times the next-largest subclass (G05D at 133), meaning most activity sits squarely in core fluid-pressure actuation and valve mechanics rather than adjacent control electronics.
- The United States leads receiving offices, but China is close behind. 281 US filings versus 178 in China and 142 at the EPO — a three-way filing footprint that any freedom-to-operate review needs to cover, not a single-jurisdiction story.
Filing growth compares 2021 (39 records) with 2024 (15) — 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 982 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks patent families published between 2015 and mid-2026 that combine core hydraulic valve terminology — hydraulic valve, proportional valve, servo valve — with technical claim language around hysteresis, flow gain, pilot-stage design, response bandwidth and pressure compensation, restricted to the F15B13, F16K31 and F15B11 IPC groups. That combination isolates control-oriented valve engineering from the far larger body of generic fluid-power patents.
982 families is a modest but well-defined corpus. It concentrates almost entirely in two IPC subclasses — F15B fluid-pressure actuators and F16K valves — with meaningful secondary activity in electronic control (G05D, G05B) and solenoid/magnetics (H01F), and smaller footprints in excavating equipment, engine valve gear and vehicle brakes that mark where hydraulic valve technology gets embedded into end applications.
Filing trend and technology composition
Two views of the same 982-family corpus: how filing volume has moved year over year, and how the classification codes split across fluid-pressure actuation, valve mechanics, electronic control and the downstream equipment that embeds them.
A peak already behind us
Filings rose from 36 in 2017 to a peak of 39 in 2021, then declined through the 2022 midpoint of 21 down toward single digits by 2026 (a partial year). Because publication lags filing by roughly 18 months, the final two years will fill in somewhat, but the shape of the decline from 2021 is already clear.
Two subclasses carry the corpus
F15B (fluid-pressure actuators and systems) and F16K (valves and taps) together account for the large majority of records, at 704 and 500 respectively out of 982 families — records can carry more than one code. G05D and G05B mark the electronic-control overlay; H01F marks solenoid and electromagnetic actuation; E02F, F01L and B60T mark the equipment context where these valves ship.
Shares are the percentage of the 982 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Hydraulic Valve and Control Technology with Eureka
This page is one run against one query. Ask Eureka your own question about hydraulic valve and control technology and every answer comes back with the patent numbers behind it.
Try EurekaCited foundations and a representative claim
US5913577A — Pilot stage of an electrohydraulic control valve
A pilot stage of an electrohydraulic control valve controls the position of a pilot actuated main stage by controlling fluid flow through a flow path that connects a supply port to an exhaust port and to an end of the main stage. A proportional valve of the pilot stage has a valve element for establishing a variable flow control orifice to control fluid flow through the flow path and a bleed orifice disposed in the flow path downstream of the proportional valve to generate fluid pressure upstream of the bleed orifice and at the end of the main stage.Filed by Caterpillar, this record illustrates the pilot-stage architecture that recurs across much of the most-cited prior art in this corpus: a proportional valve element paired with a bleed orifice to set pressure at the main-stage end, rather than direct main-stage actuation.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4635683A | Variable force solenoid | 192 |
| 2 | US4121610A | Electrically operated proportional flow control hydraulic valve and manually operable remote control device t… | 107 |
| 3 | US5211196A | Proportional seat-type 4-way valve | 104 |
| 4 | US5036886A | Digital servo valve system | 101 |
| 5 | US5806565A | Hydraulic valves | 97 |
| 6 | US4155535A | Low axial force servo valve spool | 94 |
| 7 | US4071042A | Electromagnetic actuator, notably for hydraulic servo-control valve | 93 |
| 8 | US4951549A | Digital servo valve system | 88 |
| 9 | US4979542A | Pulse modulated hydraulic valve | 86 |
| 10 | US2767689A | Electrohydraulic servo valve | 85 |
Citation counts inside a searched corpus favour older records that have had more time to accumulate references — treat this as a signal of historical influence on the field, not of current filing activity.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the filing pattern signals
Read together, the trend, classification mix and citation pattern point to a field with an established technical core and a filing rate that has already passed its peak.
Volume has already turned down
The 2021 peak of 39 families gave way to a steady decline through the 2022 midpoint of 21, down to 2 in the partial 2026 count. Even allowing for an 18-month publication lag understating the last two years, the trajectory since 2021 is a decline, not a plateau.
Two IPC subclasses hold most of the claim space
F15B (fluid-pressure actuators) and F16K (valves and taps) together dwarf every other subclass in this corpus. New filers are, almost by definition, filing into densely occupied claim territory in these two areas rather than opening new ground.
No single office dominates outright
The United States leads but China and the EPO both carry substantial shares, with Japan and the UK not far behind. Any clearance or freedom-to-operate work needs to span at least three major jurisdictions rather than treating one as a proxy for the field.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to hydraulic valve and control technology, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| VICKERS INC | BITSUKAAZU | 4 |
| Zhejiang University | Zhejiang Shengbang Technology Co., Ltd. | 2 |
| Zhejiang University | Hangzhou Shengbang Hydraulics Co., Ltd. | 2 |
| Zhejiang University | Ningbo Qianpu Machinery Manufacturing Co., Ltd. | 2 |
| Zhejiang University | Shengbang Group Co., Ltd. | 2 |
| Moog Inc. | Moog Incorporated | 2 |
| Zhejiang University | Ningbo Huaye Machinery Manufacturing Co., Ltd. | 1 |
| Zhejiang University | Shanghai Hengtuo Hydraulic Control Technology Co., Ltd. | 1 |
Only 10 co-assignee pairs appear across the corpus, and the strongest pairing outside a single Vickers/Bitsukaazu link is between a Chinese university and its affiliated hydraulics spin-off — evidence of applied research partnerships rather than broad industry consortia.
Assignee landscape and where activity has stalled
Recent-year momentum data shows established names — including Hamilton Sundstrand, Eaton, Vickers, Husco International and Moog, alongside China's Zhejiang University — all recorded zero filings in the latest year tracked. That is consistent with the broader filing decline rather than a shift away from any single player.
Established names have gone quiet recently
These assignees built out much of the historically cited prior art in this space, including foundational proportional and servo-valve patents, but none show activity in the most recent tracked year — a pattern that matches the overall post-2021 filing decline rather than an isolated retreat.
Off-highway specialists paused alongside the field
Husco's zero count in the latest year sits inside the same general slowdown visible across the corpus, rather than signalling a change specific to mobile hydraulics or excavator-adjacent valve work.
University-industry pairing concentrated in China
Zhejiang University appears in two of the ten recorded co-assignee pairs, both alongside Chinese hydraulics companies, pointing to a specific applied-research channel distinct from the corporate filers dominating the rest of the corpus.
| Assignee | Recent year | YoY |
|---|---|---|
| Hamilton Sundstrand | 0 | — |
| Eaton Corporation | 0 | — |
| VICKERS INC | 0 | — |
| Husco International | 0 | — |
| Zhejiang University | 0 | — |
| Moog Inc. | 0 | — |
| Denison/Lovejoy | 0 | — |
| Parker Hannifin | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is clearance, whitespace filing or competitive monitoring.
Run a freedom-to-operate check across three offices
With US, China and EPO filings all substantial, a clearance review limited to one jurisdiction will miss meaningful prior art. Pull the full family trees behind the most-cited records before committing to a claim direction.
Explore prior art in Eureka →Map the thinner sub-areas against your own claim drafts
The under-claimed branches identified here — pressure-compensated stacks, bandwidth-optimised pilot electronics, bleed-orifice feedback — are starting points, not guarantees of openness. Confirm density directly against a live claim search before filing.
Search live claim data in Eureka →Track the assignees that have gone quiet
Zero recent-year filings from several historically active assignees could mean consolidation, a shift to trade secret, or simply a mature technology base. Set up monitoring to catch the first sign of renewed activity.
Set up assignee monitoring in Eureka →Common questions about hydraulic valve patents
The corpus shows filing concentrated among a mix of legacy aerospace and industrial hydraulics firms alongside mobile-equipment specialists, with the most-cited foundational patents originating from that same group. However, several of these historically dominant assignees recorded zero filings in the most recent tracked year, so current filing leadership is more dispersed than historical citation counts alone would suggest. Anyone building a competitive map should weight recent-year filing activity separately from all-time citation counts, since the two tell different stories about who is active today versus who shaped the field historically.
Filing activity peaked in 2021 at 39 families and has declined since, with the 2022 midpoint already down to 21 and only 2 recorded in the partial 2026 year. Because patent publication typically lags filing by around 18 months, the 2025 and 2026 figures will rise somewhat as more records publish, but the multi-year decline visible from 2021 onward predates any lag effect. This pattern is more consistent with a mature, well-claimed technology area than an emerging one attracting new entrants.
Both terms appear together in this corpus's search criteria because they describe closely related but distinct control approaches: proportional valves typically use simpler, lower-cost solenoid actuation with coarser flow control, while servo valves use more precise closed-loop feedback for higher-bandwidth response. The IPC classification pattern in this dataset does not separate the two terms cleanly, since F15B13 and F16K31 cover control valve mechanisms broadly rather than distinguishing by control precision. Reading actual claim language in the most-cited records, several of which explicitly frame themselves around pilot-stage and bleed-orifice architectures, is the more reliable way to understand where a specific filing sits on that spectrum.
The United States leads receiving-office counts at 281 records, with China at 178 and the European Patent Office at 142, followed by Japan at 122 and the United Kingdom at 85. A clearance search limited to a single office would miss a substantial share of relevant prior art, particularly given China's near-two-hundred-record presence. Teams evaluating freedom to operate for a hydraulic valve product intended for global sale should budget for review across at least these three largest offices.
Relative to the dense core of F15B fluid-pressure actuator and F16K valve claims, sub-areas with thinner overlap include pressure-compensated multi-valve stack designs, bandwidth-optimised pilot-stage electronics, and bleed-orifice-based pressure feedback for main-stage sizing. These are not guarantees of open claim space, since a broader live search may surface additional prior art not captured by this dataset's specific search terms. They are, however, reasonable starting points for a novelty search given how thin the classification overlap is compared to the corpus core.
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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.