Shin-etsu Chemical Co., Ltd.

Dai Higuchi

Koji Miyata

Yuhito Doi

Ken Ohashi

Yuhito Yoneda

Shingo Hashimoto

Takanobu Inoue

A motor having improved heat resistance is provided. The motor includes a rotor comprising a rotor core, two or more slots arranged in a circumferential direction of the rotor in the rotor core, two magnets in a plate shape having a thickness in a radial direction of the rotor, and divided and arranged in the circumferential direction in each of the two or more slots, and a spacer for dividing the two magnets; and a stator disposed outside of the rotor in the radial direction with a clearance from the rotor and comprising a stator core having two or more slots wound with one or more winding wires; and the two magnets are separated from each other by the spacer, by a distance which is 10% to 50% of a circumferential length of the slot having the two magnets.

Motor and compressor

Provided is a dipole ring magnetic field generator capable of generating a substantially unidirectional magnetic field in the internal space of a ring without using permanent magnet pieces having fan-shaped or trapezoidal sections, and as a result, a smaller skew angle therein is achieved. The sections of the permanent magnet pieces are shaped to be rectangular, and a plurality of the rectangular permanent magnet pieces are circularly placed at predetermined positions. Each of first, second, third and fourth permanent magnet units, which are main permanent magnet units, comprises five or more permanent magnet pieces. The first and third permanent magnet units, as well as the second and fourth permanent magnet units, are positioned oppositely from each other with respect to a central axis of the magnetic field generator and have hollow shapes or E-shapes facing against each other in a section perpendicular to the central axis.

Dipole ring magnetic field generator

A method of making a cylindrical magnetic circuit which is able to prevent deformation of a cylindrical yoke for holding two or more magnets without increasing the thickness of the yoke more than required, A method of producing a cylindrical magnetic circuit () for generating a magnetic field in a space inside of plural annularly placed magnets (), including: a cylindrical yoke () which is placed radially outside the magnets () and is fixed to the magnets directly or via an intermediate member or substance; and at least one nonmagnetic member () existing between pairs of circumferentially adjacent magnets.

Method of producing a cylindrical magnetic circuit

Provided is a technology for enhancing the reliability of a permanent magnet rotating machine against thermal degradation of a permanent magnet. Specifically, provided is a permanent magnet rotating machine comprising a housing which houses a rotation shaft, a rotor connected to the rotation shaft and configured to rotate together with the rotation shaft, a stator, and permanent magnets fastened to the rotor or the stator; an air intake port provided at one end of the housing and an air exhaust port provided at the other end of the housing, the air intake port and the air exhaust port being configured to allow cooling air to flow through the housing; and a blower for feeding the cooling air to the air intake port; wherein the permanent magnet rotating machine is configured to be driven by magnetic force of the permanent magnets, and among the permanent magnets, a permanent magnet in the air exhaust port side has a higher coercivity than a permanent magnet in the air intake port side.

Permanent magnet rotating machine

A cylindrical magnetic circuit which is able to prevent deformation of a cylindrical yoke for holding two or more magnets without increasing the thickness of the yoke more than required, and a method of producing such a circuit. A cylindrical magnetic circuit () for generating a magnetic field in a space inside of plural annularly placed magnets (), including: a cylindrical yoke () which is placed radially outside the magnets () and is fixed to the magnets directly or via an intermediate member or substance; and at least one nonmagnetic memberexisting between pairs of circumferentially adjacent magnets, and a method for producing the cylindrical magnetic circuit ().

Cylindrical magnetic circuit and producing method thereof

A high-performance variable-magnetic-field dipole-ring magnetic circuit is provided. Specifically, provided is a permanent-magnet magnetic field generator having inner and outer dipole rings which share a central axis, and a yoke which surrounds the dipole rings, wherein a unidirectional variable magnetic field is generated in a space within the inner dipole ring. The generator has a fastener for fixing the inner dipole ring, and a rotator for allowing the outer dipole ring to rotate around the central axis. In the generator, each of the inner and outer dipole rings has a plurality of permanent magnets arranged in such a ring shape that a magnetization direction of the permanent magnets can make a full rotation per half circle of the ring.

Permanent-magnet magnetic field generator

It is an object of the present invention to achieve a magnetic field with high uniformity and low skew angle in a dipole ring magnetic field generating apparatus. There is provided a permanent magnet type magnetic field generating apparatus comprising: a plurality of permanent magnet pieces disposed in a ring shape so that a substantially unidirectional magnetic field is generated in a space within the ring, the permanent magnet pieces having the magnetization direction undergoing one rotation over a half-circumference of the ring, the permanent magnet pieces having substantially the same magnetic strength, and the permanent magnet pieces being disposed so as to form indentations and protrusions toward a center axis of the ring, or having a shape having indentations and protrusions facing the center axis.

Permanent magnet type magnetic field generating apparatus

To reduce the skew angle components in a dipole ring magnetic field generating device, a magnetic field generating deviceis provided in which comprises: a plurality of magnet elementstoarranged in a ring shape such that a magnetization direction of the magnet elements undergoes one rotation over half a circumference of the ring, wherein the magnet elements generate a substantially unidirectional magnetic field in a space within the ring; and corrective magnetstoarranged on an outer edge portion forming an aperture in a Z-axis direction of the magnetic field generating device, wherein the Z-axis is defined as a central axis of the magnetic field generating device, the Y-axis is defined as a direction perpendicular to the Z-axis and parallel to the unidirectional magnetic field, and the X axis is defined as a direction perpendicular to the Z axis and the Y axis.

Permanent magnet-type magnetic field generating device

The present invention provides a magnetic field generator for MRI in which, by simplifying the component parts of the pole pieces incorporated therein, the magnetic field generator for MRI can be manufactured at a lower cost without detracting from its magnetic characteristics. Specifically, the present invention provides an inclined magnetic field generation coil for use in a magnetic field generator for MRI, the coil comprising a plurality of magnetic field regulating holes (), an electric conductor in coiled form, and a resin base. Moreover, it also provides a magnetic field generator for MRI comprising a pair of permanent magnets magnetized in the direction of the thickness and opposed to each other with a gap left therebetween, and a pair of pole pieces having a peripheral projection and disposed on the opposed faces of the respective permanent magnets, in order to create a uniform magnet field space between the pole pieces, the magnetic field generator further comprising an inclined magnetic field generator () disposed within each of the pole pieces and having a mechanism () for regulating the magnetic field nonuniformity of the uniform magnet field space.

Inclined magnetic field generation coil and magnetic field generator for MRI

It is an object of the present invention to facilitate adjustment of magnetic fields. There is provided a magnetic circuit with opposing permanent magnets, comprising: a pair of permanent magnets opposing each other across a gap, the pair of permanent magnets being magnetized in thickness direction; a yoke magnetically coupled to the permanent magnets, and provided outside of the permanent magnets and the gap; a pair of pole pieces each arranged on a gap side of an opposing surface of each of the permanent magnets and having a peripheral projection in opposing direction; and an adjustment permanent magnet piece having magnetic flux amount of at most 2&#xd7;10Wb provided so as to magnetically communicate with a magnetic field formed in the gap.

Magnetic circuit with opposing permanent magnets and method for adjusting magnetic field thereof

To reduce the cost of the magnet of magnetic circuits with opposing permanent magnets by ensuring that inexpensive magnets having a low coercive force can be used without substantial loss of magnetism caused by demagnetization fields, there is provided a magnetic circuit with opposing permanent magnets, comprising: a pair of permanent magnet units opposing each other across a gap, the pair of permanent magnets being magnetized in thickness direction, wherein each of the permanent magnet units comprises at least two types of permanent magnet pieces with different coercive forces, and wherein, the permanent magnet piece that receives the largest demagnetization force when the permanent magnet units are manufactured has a larger coercive force than at least one other type of the permanent magnet piece; a yoke magnetically coupled to the permanent magnet units, and provided outside of the permanent magnet units and the gap; and a pair of pole pieces each arranged on a gap side of an opposing surface of each of the permanent magnet units and having a peripheral projection in opposing direction.

Magnetic circuit with opposing permanent magnets

The present invention provides a magnetic field generator for MRI in which, by simplifying the component parts of the pole pieces incorporated therein, the magnetic field generator for MRI can be manufactured at a lower cost without detracting from its magnetic characteristics. Specifically, the present invention provides an inclined magnetic field generation coil for use in a magnetic field generator for MRI, the coil comprising a plurality of magnetic field regulating holes ( ), an electric conductor in coiled form, and a resin base. Moreover, it also provides a magnetic field generator for MRI comprising a pair of permanent magnets magnetized in the direction of the thickness and opposed to each other with a gap left therebetween, and a pair of pole pieces having a peripheral projection and disposed on the opposed faces of the respective permanent magnets, in order to create a uniform magnet field space between the pole pieces, the magnetic field generator further comprising an inclined magnetic field generator ( ) disposed within each of the pole pieces and having a mechanism ( ) for regulating the magnetic field nonuniformity of the uniform magnet field space.

The present invention provides is an improvement in a magnetic circuit system with a pair of opposite permanent magnets to construct an MRI instrument comprising a pair of upper and lower permanent magnets connected with yokes to form an air gap space therebetween, in which the patient under MRI inspection is kept lying, a pair of shimmed pole pieces each mounted on the permanent magnet to face the air gap and a pair of gradient coils each mounted on the shimmed pole piece to face the air gap. The improvement comprises mounting a cancellation magnetic plate, which is a thin plate of a magnetic material having a coercive force of 0.1 to 500 Oe, on the gradient coil to face the air gap with an object to cancel the residual magnetization of the shimmed pole piece by the gradient magnetic field. The cancellation magnetic plate has a thickness not exceeding 0.5 mm and has a base area which is 5 to 75% relative to the base area of the gradient coil.

Magnetic circuit system with opposite permanent magnets

Proposed is an improvement in a magnet assembly of an MRI instrument of the permanent magnet type comprising a pair of permanent magnets facing each other and forming a magnet gap therebetween. A pair of pole pieces each of which are mounted on one of the permanent magnets and a pair of gradient-field coils each of which are mounted on one of the pole pieces where both the pole pieces and coils face the gap. With an object of the invention to cancel the adverse influences caused by the residual magnetization of the pole pieces by the gradient magnetic field generated in the gradient-field coils. The invention proposes providing a pair of magnetic-field compensation members each on one of the gradient-field coils so that the residual magnetization in the compensation members generates a magnetic field which is compensatory for the magnetic field due to the residual magnetization in the pole pieces.

Growing community of inventors

Echizen, Japan

Dai Higuchi