Magnetic flux device for measuring rotary motions and for generating an electric alternating signal representative of the rotary motions

A device for measuring rotary motions and for generating an electric alternating signal representative of the rotary motion, with a signal generator which rotates with the part performing the rotary motion, with a stationary inductive transducer furnished with a measuring coil with a coil core and pole shoes, and wherein a magnetic flux travels through the measuring coil and is influenced by the signal generator at both axial ends of the coil, characterized in that the signal generator is provided with two toothed wheels coupled to each other at least one of coaxially and in parallel, between which the transducer is interposed, in that the coil core consists of a permanent magnet magnetized perpendicularly to the coil axis and of two elongated pole shoes which are provided on the pole surfaces of the magnet and arranged parallel to the coil axis and whose end pieces protrude from both axial ends of the coil and reach as far as the toothings, as well as in that the toothed wheels and the pole shoes are designed and arranged such that, any time the end piece of one pole shoe is opposite to a tooth, the end piece of the second pole shoe protruding from the second coil side is likewise opposite to a tooth, the other two end pieces of the pole shoes being opposite to tooth gaps so that during the rotary motion the magnetic flux alternately passes via the end piece of one pole shoe in one direction to the diametrical end piece of the pole shoe arranged on the second pole surface, thereupon passing in another direction via the other two end pieces of the pole shoes, etc.

A device for measuring rotary motions of a rotating part and for generating electric alternating signals representative of said rotary motions, said device comprising:

• a signal generator ring having a perimeter and a center:
• (a) comprising a toothed wheel having teeth directed inwardly toward said center and having tooth gaps,
• (b) adapted for connection to and rotation with a rotating part, and
• (c) defining an area within said perimeter;
• and
• a stationary inductive transducer disposed at least partly in the area defined by said signal generator ring and having a double-sided measuring system including:
• (a) a measuring coil having an axis disposed along a diameter of said signal generator ring,
• (b) a coil core having a permanent magnet with pole surfaces magnetized perpendicularly to said coil axis, and
• (c) elongated pole shoes which are disposed on said pole surfaces of said permanent magnet parallel to said coil axis, and which have end pieces adapted to protrude from both axial ends of said measuring coil and to extend toward said signal generator ring;
• said stationary inductive transducer developing a magnetic flux through said measuring coil which is influenced by said signal generator ring at both axial ends of said measuring coil, and
• said inwardly directed teeth and tooth gaps of said signal generator ring and said pole shoes disposed such that any time the end piece of one of said pole shoes is opposite a tooth, the end piece of another of said pole shoes protruding from the opposite coil end is also opposite a tooth and the other end pieces of said pole shoes are opposite tooth gaps, so that, during rotary motion, said magnetic flux alternately passes from the end piece of one of said pole shoes to the opposite end piece of another of said pole shoes in one direction, and between the other end pieces of said pole shoes in another direction.

A device for measuring rotary motion of a rotating part and for generating an electric alternating signal representative of the rotary motion, said device comprising:

• signal generator rings:
• (a) comprising toothed wheels coupled with each other at least one of coaxially and in parallel,
• (b) adapted for connection to and rotation with said rotating part, and
• (c) having teeth and tooth gaps;
• and
• a stationary inductive transducer disposed between said toothed wheels and having:
• (a) a measuring coil having an axis,
• (b) a coil core having a permanent magnet with pole surfaces and magnetized perpendicularly to said coil axis, and
• (c) elongated pole shoes which are disposed on said pole surfaces of said magnet parallel to said coil axis, and which have end pieces adapted to protrude from both axial ends of the coil and to extend toward said inwardly directed teeth;
• said stationary inductive transducer developing a magnetic flux through the measuring coil which is influenced by said signal generator rings on both axial ends of said double-sided measuring coil, and
• said toothed wheels and said pole shoes disposed so that, any time the end piece of one of said pole shoes is opposite a tooth, the end piece of another of said pole shoes protruding from the opposite coil end is also opposite a tooth and the other end pieces of said pole shoes are opposite tooth gaps so that, during rotary motion, said magnetic flux alternately passes from the end piece of one of said pole shoes to the opposite end piece of another of said pole shoes in one direction, and between the other end pieces of said pole shoes in another direction.

A method of measuring rotary motion of a rotating part and of generating electric alternating signals representative of the rotary motion using a stationary inductive transducer having a permanent magnet core and pole shoes attached to said core with end portions of the pole shoes extending beyond axial ends of the stationary inductive transducer, and using a signal generator ring having a perimeter with spaced portions thereon that are adapted to create a magnetic flux through said stationary inductive transducer when the portions are adjacent the end portions of the pole shoes, said method comprising the steps of:

• connecting said signal generator ring to said rotating part;
• creating a reversible magnetic flux through said stationary inductive transducer by having said spaced portions on said signal generator ring alternately rotate from a first position wherein an end portion of one of said pole shoes extending from one axial end of said stationary inductive transducer and an end portion of another of said pole shoes extending from the opposite axial end of said stationary inductive transducer, are adjacent said portions of said signal generator ring, while the remaining end portions of said pole shoes are adjacent spaces between said portions, to a second position wherein the end portions that were adjacent said portions of said signal generator ring are adjacent spaces, and the end portions that were adjacent spaces are adjacent said portions of said signal generator ring, said magnetic flux travelling through said stationary inductive transducer alternately in two opposite directions and being influenced by said signal generator ring at both axial ends of said stationary inductive transducer as a result of said portions of said signal generator ring rotating past said end portions of said pole shoes;
• and
• measuring the frequency of changes in the value of said magnetic flux resulting from reversal of the magnetic flux and using said changes to determine the speed of rotation of said rotating part.

A device for measuring rotary motions of a rotating part and for generating electric alternating signals representative of said rotary motions, said device comprising:

• a signal generator ring having a center comprising a toothed wheel having teeth directed inwardly toward said center and tooth gaps and adapted for connection to and rotation with a rotating part;
• and
• a stationary inductive transducer disposed at least partly within said signal generator ring and having a double-sided measuring system including:
• (a) a measuring coil having an axis disposed along a diameter of said signal generator ring,
• (b) a permanent magnet coil core magnetized perpendicularly to said coil axis, and
• (c) first and second pole shoes:
• (1) on surfaces of said coil core,
• (2) arranged parallel to said coil axis,
• (3) each having ends which protrude from both axial ends of said coil and extend toward said signal generator ring, and
• (4) disposed relative to said signal generator ring such that any time the end piece of one of said pole shoes is opposite a tooth, the end piece of another of said pole shoes protruding from the opposite coil end is also opposite a tooth and the other end pieces of said pole shoes are opposite tooth gaps, so that, during rotary motion, a magnetic flux is developed through said measuring coil, said magnetic flux
• (i) being influenced by said signal generator ring at both axial ends of said measuring coil, and
• (ii) alternately passing between said pole shoes through said coil core in a first direction and between said pole shoes through said coil core in a second direction opposite to said first direction.