A magnetic sensor includes a magnetic sensitive member 11 including an amorphous wire, a detection coil 12 wound around the magnetic sensitive member 11, and a sample-and-hold circuit for detecting a voltage induced in the amorphous wire 11 when a pulse current is interrupted. The sample-and-hold circuit has a sample-and-hold unit B31 and a delay circuit. The sample-and-hold unit B31 includes an electronic switch S31, a capacitor C32, a resistor R32, a resistor R33, and a high-input amplifier A31. The delay circuit includes a resistor R31 connected to a control terminal of the electronic switch S31 and a capacitor C31.

An alloy for bonded magnets of the present invention includes at least a main component of iron (Fe), 12-16 atomic % (at %) of rare-earth elements (R) including yttrium (Y), and 10.8-15 at % of boron (B), and is subjected to a hydrogen treatment method as HDDR process or d-HDDR process. Using the magnet powder obtained from carrying out d-HDDR processing, etc. on this magnet alloy, pellets with superior insertion characteristics into bonded magnet molding dies can be obtained, and bonded magnets with superior magnetic properties and showing low cost can be obtained.

The aim of the present invention is to offer a keeper for a dental magnetic attachment that is strong, has low manufacturing costs, and is not easily detached from the tooth root. The keeper proposed herein has a keeper body, which is shaped like a plate, and a root, which is attached to the bottom of the keeper body. The keeper body and the root are machined from a single piece of soft magnetic material in one piece. The root has a smaller diameter part that is linked to a larger diameter part whose external diameter is larger than an external diameter of the smaller diameter part. The smaller diameter part is linked to the bottom of the keeper. There are multiple circumferential grooves around the outer side of the larger diameter part.

The challenge to be solved by the present invention is the miniaturization of a 1-300 W class of motor. This can be achieved by using a hollow-cylinder shaped anisotropic bonded magnet magnetized in a 4-pole configuration. The anisotropic bonded magnet has a maximum energy product approximately 4 times greater than the conventional sintered ferrite magnets. The use of a 4-pole configuration shortens the magnetic path length of the individual magnetic circuits and the magnetic force contributing to the torque is increased. When the torque is kept the same as in the conventional motor, the length of the electromagnetic rotor core and the axial magnet length can be reduced. In this fashion, 1-300 W class motors can be reduced in size.

This invention aims to provide a manufacturing method of an anisotropic magnet powder from which a bonded magnet with an improved loss of magnetization due to structural changes can be achieved. This is achieved by employing a low-temperature hydrogenation process, high-temperature hydrogenation process and the first evacuation process to an RFeB material (R: rare earth element) to manufacture a hydride powder (RFeBHx); the obtained RFeBHx powder (the precursory anisotropic magnet powder) is subsequently blended with a diffusion powder composed of hydride of dysprosium or the like and a diffusion heat-treatment process and a dehydrogenation process are employed. Through this series of processes, an anisotropic magnet powder with a great coercivity and a great degree of anisotropy can be achieved.