Automatic balancing apparatus

An automatic balancing apparatus comprising:

• a support shaft which is rotated by a drive;
• a case body which is fixed to said support shaft and which rotates together with said support shaft;
• a ring magnet which is placed at the inside corner, in the radial direction, of an inner space of said case body;
• and
• a balancing member, said balancing member further comprising a plurality of magnetic bodies which are movable in said inner space of said case body and which can be drawn up by the magnetic field of said ring magnet;
• wherein, when the rotational frequency of a rotor, which rotates together with said case body, exceeds the resonant frequency, said automatic balancing apparatus reduces vibrations of said rotor, and the outer circumference of said ring magnet has a number of magnetized portions wherein the number of said magnetized portions is equal to or higher than the number of said balancing member.

An automatic balancing apparatus comprising:

• a support shaft which is rotated by a drive;
• a case body which is fixed to said support shaft and which rotates together with said support shaft;
• and
• a plurality of balancer members which are movable in a inner space of said case body;
• wherein, when the rotational frequency of a rotor, which rotates together with said case body, exceeds the resonant frequency, said automatic balancing apparatus (1) reduces vibrations of said rotor;
• and (2) the inside of said case body has (i) a holding portion which prevents said plurality of balancer portions from moving outward in the radial direction when said rotor is at rest and at the beginning of the rotation of said rotor;
• (ii) a first operating portion which reduces vibrations of said rotor by preventing said plurality of balancer members from further shifting outward in the radial direction when the shift of said balancer members occurs with the holding force of said holding portion as the rotational frequency of said rotor exceeds the resonant frequency;
• and (iii) a second operating portion which reduces vibrations of said rotor, rotating at a rotational frequency exceeding a given value, by preventing said balancer members from further shifting outward in the radial direction beyond said first operating portion when the rotational frequency of said rotor exceeds said given value which is beyond the resonant frequency.

An automatic balancing apparatus comprising:

• a support shaft which is rotated by a drive;
• a case body which is fixed to said support shaft and which rotates together with said support shaft;
• a ring magnet which is placed at the inside corner, in the radial direction, of an inner space of said case body;
• and
• a balancing member, said balancing member further comprising a plurality of magnetic bodies which are movable in said inner space of said case body and which are drawn up by the magnetic field of said ring magnet;
• wherein, when the rotational frequency of a rotor, which rotates together with said case body, exceeds the resonant frequency, said automatic balancing apparatus reduces vibrations of said rotor;
• and the outer circumference of said ring magnet has a flat portion.

An automatic balancing apparatus comprising:

• a support shaft which is rotated by a drive;
• a case body which is fixed to said support shaft and which rotates together with said support shaft;
• a ring magnet which is placed at the inside corner, in the radial direction, of an inner space of said case body;
• and
• a balancing member, said balancing member further comprising a plurality of magnetic bodies which are movable in said inner space of said case body and which are drawn up by the magnetic field of said ring magnet;
• wherein, when the rotational frequency of a rotor, which rotates together with said case body, exceeds the resonant frequency, said automatic balancing apparatus reduces vibrations of said rotor;
• and the outer circumference of said ring magnet has a plurality of magnetized portions wherein the number of said magnetized portions is equal to or higher than the number of said balancing members.