Magnetic bearing devices

Claim 2

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, said one of said first and second groups of teeth having a fewer number of teeth than said other of said first and second groups of teeth.

Claim 3

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, said teeth of said one of saiD first and second groups of teeth being provided with predetermined surface portions which are smaller in area than the predetermined surface portions of said teeth of said other of said first and second groups of teeth.

Claim 4

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, said teeth of said one of saiD first and second groups of teeth being provided with predetermined surface portions which are smaller in area than the predetermined surface portions of said teeth of said other of said first and second groups of teeth.

Claim 5

A magnetic bearing device according to claim 2, wherein the predetermined surface portions are narrowed portions of said teeth.

Claim 6

A magnetic bearing device according to claim 3, wherein the narrowed portions are provided at the tips of said teeth.

Claim 7

A magnetic bearing device according to claim 2, wherein said plurality of teeth of each of said groups are formed as concentric circular rings on the opposing surfaces of said rotatable member and said stationary member means, each of the opposing teeth being provided with a substantially planar surface at the tip thereof.

Claim 8

A magnetic bearing device according to claim 2, wherein said rotatable member is disk-shaped and said stationary member means includes first and second annular members disposed on opposite sides of said rotatable member.

Claim 9

A magnetic bearing device according to claim 2, wherein the rotatable body is vertically disposed for rotation and said magnetic bearing device is vertical magnetic bearing device having said rotatable member secured at the upper end portion of said rotatable body, the first and second oppositely facing surfaces of said rotatable member being upper and lower side surfaces of said rotatable member, said magnetic bearing device providing a force for relieving a supporting force for a contact type bearing device disposed on the lower end portion of the rotatable body.

Claim 10

A magnetic bearing device according to claim 7, wherein said rotatable member is disk-shaped and said stationary member means include first and second annular members disposed on opposite sides of said rotatable member, said teeth of said one of said first and second groups being disposed at the outer portions of said rotatable member as compared with said teeth of said other of said first and second group.

Claim 11

A magnetic bearing device according to claim 8, wherein said teeth of said other of said first and second groups are disposed at outer and inner portions of said rotatable member.

Claim 12

A magnetic bearing device according to claim 7, wherein said one of said first and second groups is the group of teeth disposed at the lower side of the rotatable member.

Claim 13

A magnetic bearing device according to claim 2, wherein said means for providing magnetic paths include exciting coil means and said stationary member means includes first and second annular members disposed on opposite sides of said rotatable member and a member interconnecting said annular members and partially surrounding said exciting coil means.

Claim 14

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, said plurality of teeth of each of said groups including a plurality of individual teeth arranged along concentric circular paths.

Claim 15

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, said plurality of teeth of each of said groups including a plurality of individual teeth arranged along concentric circular paths.

Claim 16

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation tHerewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, the rotatable body being vertically disposed for rotation and said magnetic bearing device being a vertical magnetic bearing device having said rotatable member secured at the upper end portion of said rotatable body, the first and second oppositely facing surfaces of said rotatable member being upper and lower side surfaces of said rotatable member, said magnetic bearing device providing a force for relieving a supporting force for a contact type bearing device disposed on the lower end portion of the rotatable body, said rotatable member being disc-shaped and said stationary member means including first and second annular members disposed on opposite sides of said rotatable member, said teeth of said one of said first and second groups being disposed at the outer portions of said rotatable member as compared with said teeth of said other of said first and second group, said teeth of said first and second groups having the area of the tips thereof gradually increased in area in the direction from an outer tooth to an inner tooth.

Claim 17

A magnetic bearing device comprising a rotatable member secured to a rotatable body for rotation tHerewith, said rotatable member being formed of a magnetic material and having first and second oppositely facing surface portions, stationary member means formed of a magnetic material and having surface portions disposed in opposing relation to the first and second surface portions of said rotatable member, first and second groups of teeth, each of said groups of teeth including a plurality of opposing teeth formed respectively along concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member and adapted to magnetically saturate the teeth of said groups, one of said first and second groups of teeth being arranged to become magnetically saturated before the other of said first and second groups of teeth, the rotatable body being vertically disposed for rotation and said magnetic bearing device being a vertical magnetic bearing device having said rotatable member secured at the upper end portion of said rotatable body, the first and second oppositely facing surfaces of said rotatable member being upper and lower side surfaces of said rotatable member, said magnetic bearing device providing a force for relieving a supporting force for a contact type bearing device disposed on the lower end portion of the rotatable body, said rotatable member being disc-shaped and said stationary member means including first and second annular members disposed on opposite sides of said rotatable member, said teeth of said one of said first and second groups being disposed at the outer portions of said rotatable member as compared with said teeth of said other of said first and second group, said teeth of said first and second groups having the area of the tips thereof gradually increased in area in the direction from an outer tooth to an inner tooth.

Claim 18

A vertical magnetic bearing device including a rotatable member secured to an upper portion of a vertically disposed rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having upper and lower side portions, stationary member means disposed at the upper and lower side portions of said rotatable member and formed of a magnetic material, upper and lower groups of teeth, each of said groups including a plurality of opposing teeth formed respectively in concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member means such that at least the teeth of one of said groups become magnetically saturated whereby the magnetic bearing device provides a force for relieving a supporting force for a contact type bearing device disposed at the lower portion of the rotatable body, the teeth of the at least one group which becomes magnetically saturated being disposed at outer portions of said rotatable member and said stationary member means as compared with the teeth of the other of said groups, the tips of the teeth of said groups being gradually increased in area in the direction, from an outer tooth to an inner tooth.

Claim 19

A vertical magnetic bearing device including a rotatable member secured to an upper portion of a vertically disposed rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having upper and lower side portions, stationary member means disposed at the upper and lower side portions of said rotatable member and formed of a magnetic material, upper and lower groups of teeth, each of said groups including a plurality of opposing teeth formed respectively in concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member means such that at least the teeth of one of said groups become magnetically saturated whereby the magnetic bearing device provides a force for relieving a supporting force for a contact type bearing device disposed at the lower portion of the rotatable body, the teeth of the at least one group which becomes magnetically saturated being disposed at outer portions of said rotatable member and said stationary member means as compared with the teeth of the other of said groups, the tips of the teeth of said groups being gradually increased in area in the direction, from an outer tooth to an inner tooth.

Claim 20

A vertical magnetic bearing device according to claim 14, wherein the teeth of the at least one group which becomes magnetically saturated are disposed at outer portions of said rotatable member and said stationary member means as compared with the teeth of the other of said groups, each of the teeth having a substantially planar surface at the tip thereof.

Claim 21

A vertical magnetic bearing device including a rotatable member secured to an upper portion of a vertically disposed rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having upper and lower side portions, stationary member means disposed at the upper and lower sIde portions of said rotatable member and formed of a magnetic material, upper and lower groups of teeth, each of said groups including a plurality of opposing teeth formed respectively in concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member means such that at least the teeth of one of said groups become magnetically saturated whereby the magnetic bearing device provides a force for relieving a supporting force for a contact type bearing device disposed at the lower portion of the rotatably body, the teeth of the at least one group which becomes magnetically saturated being disposed at outer portions of said rotatable member and said stationary member means as compared with the teeth of the other of said groups, the tips of the teeth of said groups being gradually narrowed in area in the direction from an inner tooth to an outer tooth.

Claim 22

A vertical magnetic bearing device including a rotatable member secured to an upper portion of a vertically disposed rotatable body for rotation therewith, said rotatable member being formed of a magnetic material and having upper and lower side portions, stationary member means disposed at the upper and lower sIde portions of said rotatable member and formed of a magnetic material, upper and lower groups of teeth, each of said groups including a plurality of opposing teeth formed respectively in concentric paths on opposing surfaces of said rotatable member and said stationary member means with gaps being provided between the opposing teeth of each of said groups, and means for providing magnetic paths between said rotatable member and said stationary member means such that at least the teeth of one of said groups become magnetically saturated whereby the magnetic bearing device provides a force for relieving a supporting force for a contact type bearing device disposed at the lower portion of the rotatably body, the teeth of the at least one group which becomes magnetically saturated being disposed at outer portions of said rotatable member and said stationary member means as compared with the teeth of the other of said groups, the tips of the teeth of said groups being gradually narrowed in area in the direction from an inner tooth to an outer tooth.