32results about How to "Improve magnetic circuit efficiency" patented technology

A magnetic field generator (10) capable of generating a more intense magnetic field, and an MRI apparatus (200) using it are provided. Permanent magnets (12a), (12b), (14a), (14b), (16a), (16b), (18a), (18b), (20a), (20b), (22) and (24) are disposed annularly for formation of a magnetic field generation space (30). Ferromagnetic materials (26a) and (26b) are provided near the magnetic field generation space (30), at places passed by a magnetic flux. Each of the permanent magnets (12a), (14a), (16a), (18a) and (20a) surrounding the ferromagnetic material (26a) is magnetized so as to make an S pole on the side of the ferromagnetic material (26a). Each of the permanent magnets (12b), (14b), (16b), (18b) and (20b) surrounding the ferromagnetic material (26b) is magnetized so as to make an N pole on the side of the ferromagnetic material (26b). An MRI apparatus (200) is obtained by using the magnetic field generator (10).

A rotational coupling device for use as a clutch and / or brake is provided having improved magnetic efficiency and structural integrity. A permanent magnet is coupled to one of a brake plate and an armature and axially aligned with a portion of the other for improved braking performance.

According to a solenoid air valve, a flange portion of a moving core and a flange portion area of a bobbin implement a stop area defining a distance of travel of the moving core in a direction away from a fixed core. An end portion of a shaft portion of the moving core can project outward through an opening of a frame cover, so that a gap between a surface of the frame cover facing the shaft portion and a side surface of the shaft portion (distance: L2) can be minimized. Consequently, a solenoid air valve having a structure allowing improvement in magnetic efficiency by making smaller the gap between the frame and the moving core is provided.

A magnetic sector for charged particle beam transport that includes a magnetic field profile that achieves a linear dispersion from a collimated beam of charged particles proportional to their mass-energy-to-charge ratio. In one embodiment, the field profile necessary for the linear dispersion is obtained by the use of shaped, highly permeable poles powered by permanent magnets or electromagnetic coils.

The invention provides a sound production device, which comprises a bracket, and a magnetic circuit system, a first vibration system and a second vibration system which are fixedly connected to the bracket, the bracket is provided with a first opening and a second opening which face opposite directions, and the magnetic circuit system is used for driving the first vibration system and the second vibration system to produce sounds in different directions. The first vibration system comprises a first voice coil, the second vibration system comprises a second voice coil, the magnetic circuit system comprises first magnetic steel, second magnetic steel and third magnetic steel which are sequentially arranged at intervals and oppositely arranged in the second direction, and the polarity of a magnetic pole, opposite to the second magnetic steel, in the first magnetic steel is the same as that of a magnetic pole, opposite to the first magnetic steel, in the second magnetic steel. The polarityof a magnetic pole, opposite to the third magnetic steel, in the second magnetic steel is the same as the polarity of a magnetic pole, opposite to the second magnetic steel, in the third magnetic steel, the first voice coil sleeves the first magnetic steel and the second magnetic steel at the same time, and the second voice coil sleeves the second magnetic steel and the third magnetic steel at the same time. According to the invention, the loudness of the sound produced by the sound production device can be improved.

The invention provides an objective lens driving apparatus in which an efficiency of a magnetic circuit is improved by making a magnetic flux density distribution of the objective lens driving apparatus close to symmetrical. An objective lens driving apparatus has an objective lens, a tracking coil driving the objective lens in a tracking direction, a focusing coil driving the objective lens in a focusing direction, and a yoke arranged so as to oppose to the tracking coil and having a permanent magnet attached thereto. The yoke has a bottom plate portion and an outer yoke bent approximately perpendicularly to the bottom plate portion from an outer edge portion of the bottom plate portion, has a first yoke having an opening formed in a center portion thereof, and a second yoke having a bottom plate portion and an inner yoke bent approximately perpendicularly to the bottom plate portion from an inner edge portion of the bottom plate portion, and having an opening formed in a center portion thereof.

A drive apparatus comprising a stationary frame with a coil, a movable frame with a magnetic circuit held movably in a direction orthogonal to a first direction, and a drive unit that moves the movable frame by applying electric current to the coil. The magnetic circuit is constituted by aligning a first magnet having a magnetization direction parallel to the first direction, a second magnet having a magnetization direction opposite to the first magnet, and a third magnet between the first and second magnets in a direction orthogonal to the first direction. The third magnet has a magnetization direction that has a pole in the same direction of the poles of the first and second magnets when viewed from the coil side. The side spaces of the first and second magnets opposite to the third magnet are occupied by material whose magnetic permeability is lower than the magnets.

The invention discloses a miniature power generation device, and relates to the technical field of a power generation device. The miniature power generation device comprises a moving part and an iron core, wherein the iron core is matched with the moving part, the moving part comprises a magnet rack, installation grooves are formed in the upper side and the lower side of the magnet rack, magnetic conduction sheets are arranged in the installation grooves, a magnet is arranged between the two magnetic conduction sheets, an operation head is arranged at one end of the magnet rack, one end, far away from the operation head, of the magnet rack extends to the iron core, the magnet rack rotates around the iron core, a limitation device is arranged on the iron core and is used for limiting the rotation of the moving part, an upper moving stop point and a lower moving stop point are formed on the limitation device, a coil winds around the iron core, and a main magnetic path, an upper branch magnetic path and a lower branch magnetic path are separately matched with different parts of the moving part. The miniature power generation device has the advantages of simplicity in structure, the module volume is reduced, the arrangement mode of a magnetic path part coordination region is changed to multi-short-line dispersion from original single-long-line dispersion along a moving direction, the power density is effectively improved, and the production process is substantially simplified.

The present invention provides a magnetron which can conduct more magnetic flux in the active space at the periphery of a cathode structure to thereby further improve the efficiency of a magnetic circuit. The magnetron of the present invention includes an anode cylinder on which inner wall a plurality of anode vanes are provided, a pole piece provided on an end side of the anode cylinder, a circular magnet provided on the vicinity of the pole piece, and a magnet ring provided between the anode cylinder and the circular magnet. An outer diameter of the magnet ring is smaller than or equal to the outer diameter of the circular magnet and larger than or equal to the outer diameter of the anode cylinder. The magnet ring has a portion on a surface of the pole piece side whose normal line is non-parallel to the central axis of the anode cylinder.

The invention provides a linear vibration motor, which comprises a magnetic circuit system and an oscillator system, wherein the magnetic circuit system comprises a main magnetic circuit system and two secondary magnetic circuit systems; the main magnetic circuit system comprises first magnetic steel, a pole shank and second magnetic steel which are sequentially stacked along the vibration direction of the oscillator system; the first magnetic steel and the second magnetic steel are arranged in a homopolar opposite manner; each secondary magnetic circuit system comprises third magnetic steel; two opposite sides of the pole shank are homopolar opposite; and the polarities of homopolar opposite magnetic poles of the third magnetic steel are opposite to that of the homopolar opposite magnetic pole of the main magnetic circuit system. Compared with a related technology, the linear vibration motor provided by the invention has the advantages that the first magnetic steel and the second magnetic steel are arranged in a homopolar opposite manner and the secondary magnetic circuit systems are arranged at two opposite sides of the main magnetic circuit system, so that the magnetic field intensity of the magnetic circuit system is increased.

The invention discloses a shearing type double-cylinder magneto-rheological damper. The shearing type double-cylinder magneto-rheological damper comprises an upper shearing plate and a lower shearing plate. The upper shearing plate is connected with a vehicle frame. The lower shearing plate is connected with a vibrating wheel. A containing cavity defined by four face plates is arranged on the lower shearing plate. A top plate is arranged on the top of the containing cavity. An open groove is formed in the top of the top plate. The containing cavity is divided by the open groove into a left containing cavity body and a right containing cavity body. Two piston cylinders are arranged in the left containing cavity body and the right containing cavity body respectively. Each piston cylinder is filled with magneto-rheological fluid. An opening of each piston cylinder is sealed with a cylinder cover with a seal ring. The two ends of a double-head piston rod extend into the piston cylinders in the left containing cavity body and the right containing cavity body respectively. Magnetic coils are wound around the two ends of the double-head piston rod respectively. A connecting rod extends downwards from the middle of the upper shearing plate. The connecting rod is connected with the middle of the double-head piston rod. The upper shearing plate conducts movement in the longitudinal direction and the transverse direction on the plane relative to the lower shearing plate under the action of the connecting rod and the double-head piston rod. By the adoption of the shearing type double-cylinder magneto-rheological damper, a primary vibration damping area of a vibration roller is obtained, and damping can be adjusted according to needs.