# US 2014/0153749 A1 · Magnetic yoke used for a moving-iron microphone/transducer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153749 A1 - Document ID: US20140153749A1 - Status: Published application - Kind: A1 - Application number: 14/233,338 - Filed: 2011-11-14 - Published: 2014-06-05 - Earliest claimed: 2011-09-27 - Assignees: Suzhou Shinwu Optronics Technology Co., Ltd - Inventors: Zhe Wu - Web page: https://patentgrep.com/patent/US20140153749A1 ## CPC - H04R 1/00: Details of transducers, {loudspeakers or microphones} - H04R 11/00: Transducers of moving-armature or moving-core type (acoustic diaphragm of magnetisable material directly coacting with electromagnet H04R13/00) - H04R 9/025: {Magnetic circuit} - H04R 9/027: {Air gaps using a magnetic fluid} - H04R 2209/024: Manufacturing aspects of the magnetic circuit of loudspeaker or microphone transducers - H04R 2400/01: Transducers used as a loudspeaker to generate sound aswell as a microphone to detect sound - H04R 2400/03: Transducers capable of generating both sound as well as tactile vibration, e.g. as used in cellular phones - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract The invention provides a magnetic yoke used for a moving-iron microphone/transducer, which comprises an inner through hole, an enclosed soft magnet and two end surfaces orthogonal to the enclosed soft magnet. The magnetic yoke is one-piece configured, the outer peripheral surface of the soft magnet and the inner through hole respectively is used for connecting with an armature and a magnetic piece of the microphone/transducer, and one of the two end surfaces is used for connecting with an induction coil of the microphone/transducer, to form a vibrating/transducing drive mechanism. The manufacturing process of the magnetic yoke comprises forming a tube by drawing process and cutting the tube. ## Claims ### Claim 1 A magnetic yoke used for a moving-iron microphone/transducer, comprising an inner through hole, an enclosed soft magnet and two end surfaces orthogonal to the enclosed soft magnet. ### Claim 2 (depends on 1) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 1, wherein an outer peripheral surface of the enclosed soft magnet is connected with an armature of the moving-iron microphone/transducer, the inner through hole is used for connecting with a magnetic piece of the moving-iron microphone/transducer, and one of the two end surfaces is used for connecting with an induction coil of the moving-iron microphone/transducer, to form a vibrating/transducing drive mechanism in the moving-iron microphone/transducer. ### Claim 3 (depends on 2) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 2, wherein the outer peripheral surface of the enclosed soft magnet is connected with the armature of the moving-iron microphone/transducer by resistance welding, laser welding, or ultrasonic welding. ### Claim 4 (depends on 1) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 1, wherein the inner through hole is connected with the magnetic piece of the moving-iron microphone/transducer by laser welding, ultrasonic welding or adhesive binding. ### Claim 5 (depends on 2) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 2, wherein one of the two end surfaces is connected with the induction coil of the moving-iron microphone/transducer by adhesive binding. ### Claim 6 (depends on 1) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 1, wherein the enclosed soft magnet of the magnetic yoke is one-piece configured, and each bend of edges of the enclosed soft magnet is provided with a design of chamfer adapted for process improvement. ### Claim 7 (depends on 1) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 1, wherein the magnetic yoke is made of soft magnetic alloy selected from soft iron with high magnetic permeability, A3 steel or Permalloy, in some particular applications, the magnetic yoke may be made from a ferrite material. ### Claim 8 (depends on 1) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 1, wherein the enclosed soft magnet can be made in different thickness and configurations according to the different functional requirements to form various shapes of outer peripheral surface and inner through hole, to meet the requirements in magnetic circuit design and mechanical assembly, and the shape of the configuration and inner through hole including (but not limited to) a rectangle with a design of chamfer, a square with a design of chamfer or H-shape with a design of chamfer. ### Claim 9 (depends on 1) The magnetic yoke used for a moving-iron microphone/transducer as claimed in claim 1, wherein the manufacturing process for the magnetic yoke comprises steps of: drawing a soft magnetic material adapted for manufacture of the magnetic yoke to form a metal tube comprising an enclosed soft magnet and an inner through hole by adopting drawing process for metal tube; and cutting the metal tube along a direction orthogonal to the inner through hole (i.e., the direction of the end surfaces) in terms of a desired size of the magnetic yoke, to obtain the magnetic yoke. ### Claim 10 (depends on 1) A moving-iron microphone/transducer as claimed in claim 1, wherein the microphone/transducer uses the magnetic yoke which is connected with an armature of the moving-iron microphone/transducer by the outer peripheral surface of the enclosed soft magnet, the inner through hole is used for connecting with a magnetic piece of the moving-iron microphone/transducer, and one of the two end surfaces is used for connecting with an induction coil of the moving-iron microphone/transducer, to form a vibrating/transducing drive mechanism in the moving-iron microphone/transducer, when an alternating current flows through the induction coil to generate an alternating magnetic field due to an electromagnetic induction effect, the armature in the vibrating/transducing drive mechanism is magnetized, and the push-pull effect will be created between the armature and the magnetic piece due to the principle that like poles repel, unlike poles attract, thereby causing a vibration displacement of a vibration conduction device welded on the armature along a direction perpendicular to the armature, when the vibration displacement is transmitted to a diaphragm connected with the vibrating conduction device, the diaphragm vibrates and further makes its surrounding air vibrate and sound, thereby achieving the transformation of electrical energy to magnetic energy and finally to mechanical energy.