H04R 9/027
Air gaps using a magnetic fluid
Official title: {Air gaps using a magnetic fluid}
H04R9/027 (Air gaps using a magnetic fluid) appears on 135 US grants and 147 published applications in this corpus.
Search patents in H04R- Granted patents
- 135
- Published applications
- 147
- Assignees
- 67
- Inventors
- 229
- Latest grant
- 24 Mar 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 1 | 0 |
| 1982 | 1 | 0 |
| 1983 | 1 | 0 |
| 1984 | 0 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 1 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 1 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 1 | 0 |
| 2002 | 0 | 0 |
| 2003 | 1 | 2 |
| 2004 | 2 | 3 |
| 2005 | 2 | 2 |
| 2006 | 1 | 1 |
| 2007 | 2 | 2 |
| 2008 | 2 | 2 |
| 2009 | 0 | 5 |
| 2010 | 1 | 3 |
| 2011 | 2 | 4 |
| 2012 | 5 | 5 |
| 2013 | 4 | 7 |
| 2014 | 4 | 9 |
| 2015 | 10 | 13 |
| 2016 | 12 | 8 |
| 2017 | 9 | 1 |
| 2018 | 3 | 4 |
| 2019 | 2 | 4 |
| 2020 | 4 | 13 |
| 2021 | 9 | 7 |
| 2022 | 8 | 20 |
| 2023 | 15 | 18 |
| 2024 | 19 | 6 |
| 2025 | 7 | 4 |
| 2026 | 3 | 4 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Sound-generating device24 Mar 2026US 12,587,791 B2AAC Microtech (Changzhou) Co., Ltd.
- Speaker20 Jan 2026US 12,532,125 B2Alps Alpine Co., Ltd.
- Electromagnetic transducer with dual flux13 Jan 2026US 12,523,634 B2Cochlear Limited
- Speaker driver assembly25 Nov 2025US 12,483,837 B2Morel (IL) Ltd.
- Loudspeaker12 Aug 2025US 12,389,164 B2Panasonic Automotive Systems Co., Ltd.
- Electromagnetic transducer with dual flux20 Aug 2026US 2026/0243733 A1Cochlear Limited
- Speaker assemblies and earphones13 Aug 2026US 2026/0238919 A1Shenzhen Shokz Co., Ltd.
- Method for reducing signal distortion in an electro-mechanical transducer based on magnetic flux modes13 Aug 2026US 2026/0238922 A1
- Bone-conduction speakers and earphones23 Jul 2026US 2026/0214374 A1Shenzhen Shokz Co., Ltd.
- Acoustic electromagnetic actuator with opposed magnet and spring force and output device thereto18 Dec 2025US 2025/0386147 A1Sound Solutions International (Zhenjiang) Co., Ltd.
Most cited
By later US patents
- Hearing aid mechanism65US 7,471,805 B2Central Coast Patent Agency, Inc. · 2008
- Method and structure for inducing acoustic signals and attenuating acoustic signals53US 9,123,323 B22015
- Electrodynamic acoustic transducer with magnetic gap sealing39US 6,208,743 B1Sennheiser electronic GmbH & Co. KG · 2001
- Method for making loudspeaker with magnetic fluid enveloping the voice coil35US 4,017,694 AEssex Group, Inc. · 1977
- Low cost broad range loudspeaker and system27US 6,654,476 B12003