Temperature-compensated permanent magnet

Claim 2

A temperature-compensated permanent magnet comprising: a generally thin, permanent magnet body molded from a high coercive force, low-permeability material having first and second surfaces, the distance between said surfaces defining the thickness of said body; said body being magnetized to provide magnetic poles on at least one of said surfaces with the lines of magnetic force interior of the body extending in bowed paths between the poles; temperature compensation means carried by said body for maintaining a substantially constant magnetic flux; said means being in a position where at least a majority of the lines of magnetic force in their normal path exterior of the body pass therethrough, the ratio of the area of either of said surfaces to the thickness of said body being at least equal to 25.

Claim 3

The temperature-compensated permanent magnet defined in claim 9, wherein said magnet body is a disc, the ratio of the diameter to the thickness of said disc being at least equal to 3.5.

Claim 4

The temperature-compensated magnet defined in claim 2, wherein said disc has at least two radially spaced concentric magnetic poles disposed on said first surface and said second surface includes an annular recess in which is carried said temperature compensation means.

Claim 5

The temperature-cOmpensated permanent magnet defined in claim 2, wherein said disc has a first surface including at least two radially spaced concentric magnetic poles and an annular recess in which is carried said temperature compensation means.

Claim 6

The temperature-compensated permanent magnet defined in claim 2, wherein said disc comprises first and second portions configured to fit together to define a unitary magnet body, each of said portions including said first and second surfaces, at least two radially spaced concentric poles disposed on one of said surfaces of each of said portions, one of said portions including an annular recess in which is carried said temperature compensation means, said recess being located intermediate said portions.

Claim 7

The temperature-compensated permanent magnet defined in claim 2, wherein said disc comprises first and second portions configured to fit together to define a unitary magnet body, said first portion including said first and second surfaces and said second portion having opposed axial surfaces in contact with said first portion when said portions are fitted together, said second portion further having a radially extending surface in alignment with one of said first portion surfaces when said portions are fitted together, a radially spaced concentric recess disposed in each of said opposed axial surfaces, in which is carried said temperature compensation means, one of said portions being magnetized in the radial direction and the other of said portions being magnetized in both the radial and axial directions, and all lines of magnetic force being curved between opposite polar surfaces.

Claim 8

The temperature-compensated permanent magnet defined in claim 1, wherein said temperature compensation means comprises a magnetizable material having a low Curie point.