Abstract: A first bias magnetic flux may be communicated between a first axial pole and a first axial facing surface of the body. A second bias magnetic flux may be communicated between a second axial pole and a second axial facing surface of the body. A time-varying axial control magnetic flux may be communicated through the first and second axial facing surfaces of the body, and may be generated in a magnetic circuit including the body, the first and second axial poles, and an axial magnetic backiron. The first and second axial poles may include axial pole laminated inserts composed of electrically isolated steel laminations stacked along the body axis. The axial magnetic backiron may include laminated inserts composed of electrically isolated steel laminations stacked in the direction tangential to the body axis. The axial pole laminated inserts may be magnetically coupled to the axial magnetic backiron laminated inserts.

Abstract: An electromagnetic actuator includes a body and first and second poles residing apart from the body. The first and second poles communicate magnetic flux across a gap with opposing end facing surfaces of the body. The body, the first pole, and the second pole are magnetically coupled and define an axial magnetic control circuit. A plurality of radial poles reside apart from the body, adjacent a lateral facing surface of the body, and communicate magnetic fluxes with the lateral facing surface. The body and the plurality of radial poles define a plurality of radial magnetic control circuits. The plurality of radial poles communicate magnetic fluxes with the lateral facing surface and at least one of the first pole or the second pole, and the body, the plurality of radial poles, and at least one of the first pole or the second pole define a magnetic bias circuit.

Abstract: Noncontact measuring of positions of objects is achieved through measurements of parameters characterized by the distribution of an AC magnetic flux in the air gap between stationary and moveable portions defining a sensor magnetic circuit. A sensor head fixed relative to a stationary element includes a soft-magnetic core. A sensor target is fixed relative to a movable element, the soft-magnetic core and the sensor target separated by an air gap and defining a magnetic circuit. A coil around the soft-magnetic core is adapted to produce a magnetic flux in the magnetic circuit. A magnetic flux density sensor fixed relative to the sensor head resides in the gap between the soft-magnetic core and the sensor target and is configured to detect magnetic flux density in a portion of the gap. A controller in communication with the magnetic flux density sensor is configured to receive an output signal of the magnetic flux.

Abstract: A body is equipped with magnetically connected radial and axial actuator targets. The radial actuator target features a cylindrical lateral surface. The axial actuator target features the first and the second end-facing surfaces. A radial pole is adapted to communicate a magnetic flux with the cylindrical lateral surface. Magnetically connected first and second axial poles are located axially on one side of the radial pole and adapted to communicate magnetic fluxes with the first and the second end-facing surfaces. The first axial pole, the second axial pole and the axial actuator target form a magnetic axial control circuit. The radial pole, the radial actuator target, the axial actuator target, the first axial pole and the second axial pole form the magnetic bias circuit. Superposition of magnetic fluxes in the axial control circuit and in the bias circuit results in an axial force acting on the axial actuator target.

Abstract: An electromagnetic actuator generates electromagnetic forces across large radial gaps to support a body. The actuator has an actuator target having a rotational axis, and a target magnetic element arranged circumferentially around the rotational axis that has inner and outer magnetic poles. A cylindrical soft-magnetic target pole is magnetically coupled to the outer cylindrical magnetic pole of the target magnetic element. An actuator base includes radial poles arranged circumferentially around and radially spaced apart from the cylindrical soft-magnetic target pole. The radial poles and the cylindrical soft-magnetic target pole are magnetically coupled and define a plurality of magnetic control circuits. Control coils around the radial poles are configured to produce magnetic fluxes in the magnetic control circuits.

Abstract: A body is equipped with magnetically connected radial and axial actuator targets. The radial actuator target features a cylindrical lateral surface. The axial actuator target features the first and the second end-facing surfaces. A radial pole is adapted to communicate a magnetic flux with the cylindrical lateral surface. Magnetically connected first and second axial poles are located axially on one side of the radial pole and adapted to communicate magnetic fluxes with the first and the second end-facing surfaces. The first axial pole, the second axial pole and the axial actuator target form a magnetic axial control circuit. The radial pole, the radial actuator target, the axial actuator target, the first axial pole and the second axial pole form the magnetic bias circuit. Superposition of magnetic fluxes in the axial control circuit and in the bias circuit results in an axial force acting on the axial actuator target.

Abstract: An apparatus for measuring linear velocity of a movable element relative to a stationary element includes a magnetic element fixed in relation to the stationary element. A soft-magnetic yoke is fixed in relation to the movable element to move with the movable element and is in non-contact relation with the magnetic element. A yoke pole is positioned proximate to the magnetic element and spaced therefrom by an air gap. The pole is magnetically coupled to the magnetic element so that a magnetic flux is generated in the air gap substantially orthogonal to the axis of motion. A conductive coil is coiled around a coil axis and is fixed in relation to the stationary element with the coil axis substantially parallel to the axis of movement. The coil is in non-contact relation with the yoke and resides between the magnetic element and the pole of the yoke in the magnetic flux.

Abstract: A homopolar magnetic actuator is configured to exert controllable radial forces on a body adapted to rotate around an axis. The actuator comprises at least three radial magnetic pole assemblies distributed at some distances from each other along the axis, each including a plurality of poles adjacent to an actuator target on the body. Permanent magnets are used to induce bias magnetic fluxes in the assemblies with polarities alternating from assembly to assembly but remaining the same around the rotational axis. Having several small bias fluxes distributed between several pole assemblies instead of a large single bias flux facilitates designing an actuator with a high aspect ratio. A control coil around each pole can induce a control magnetic flux in the poles. These control fluxes affect magnetic flux distribution around the actuator target, resulting in magnetic forces exerted on the target.

Abstract: An electromagnetic actuator with flux feedback control includes two poles located on opposite sides of a soft-magnetic target. A bias flux is introduced that flows into both poles. Magnetic circuitry may be designed so that the total bias flux is independent or substantially independent of a position of the target with respect to the poles or the control flux. The electromagnetic actuator also includes flux sensors introduced into each gap between the poles and the target. The electromagnetic actuator further includes an actuator control circuit to command the current in the control coil to bring a difference between the readings of the two flux sensors to a targeted level. In some aspects, the force exerted on the actuator target in this arrangement may be proportional to the command signal regardless of the position of the actuator target, MMF drop in the soft-magnetic parts of the magnetic circuit, or the frequency.

Abstract: A first bias magnetic flux may be communicated between a first axial pole and a first axial facing surface of the body. A second bias magnetic flux may be communicated between a second axial pole and a second axial facing surface of the body. A time-varying axial control magnetic flux may be communicated through the first and second axial facing surfaces of the body, and may be generated in a magnetic circuit including the body, the first and second axial poles, and an axial magnetic backiron. The first and second axial poles may include axial pole laminated inserts composed of electrically isolated steel laminations stacked along the body axis. The axial magnetic backiron may include laminated inserts composed of electrically isolated steel laminations stacked in the direction tangential to the body axis. The axial pole laminated inserts may be magnetically coupled to the axial magnetic backiron laminated inserts.

Abstract: An electromagnetic actuator includes a body and first and second poles residing apart from the body. The first and second poles communicate magnetic flux across a gap with opposing end facing surfaces of the body. The body, the first pole, and the second pole are magnetically coupled and define an axial magnetic control circuit. A plurality of radial poles reside apart from the body, adjacent a lateral facing surface of the body, and communicate magnetic fluxes with the lateral facing surface. The body and the plurality of radial poles define a plurality of radial magnetic control circuits. The plurality of radial poles communicate magnetic fluxes with the lateral facing surface and at least one of the first pole or the second pole, and the body, the plurality of radial poles, and at least one of the first pole or the second pole define a magnetic bias circuit.

Abstract: An electromagnetic actuator generates electromagnetic forces across large radial gaps to support a body. The actuator has an actuator target having a rotational axis, and a target magnetic element arranged circumferentially around the rotational axis that has inner and outer magnetic poles. A cylindrical soft-magnetic target pole is magnetically coupled to the outer cylindrical magnetic pole of the target magnetic element. An actuator base includes radial poles arranged circumferentially around and radially spaced apart from the cylindrical soft-magnetic target pole. The radial poles and the cylindrical soft-magnetic target pole are magnetically coupled and define a plurality of magnetic control circuits. Control coils around the radial poles are configured to produce magnetic fluxes in the magnetic control circuits.

Abstract: Noncontact measuring of positions of objects is achieved through measurements of parameters characterized by the distribution of an AC magnetic flux in the air gap between stationary and moveable portions defining a sensor magnetic circuit.

Abstract: An apparatus for measuring linear velocity of a movable element relative to a stationary element includes a magnetic element fixed in relation to the stationary element. A soft-magnetic yoke is fixed in relation to the movable element to move with the movable element and is in non-contact relation with the magnetic element. A yoke pole is positioned proximate to the magnetic element and spaced therefrom by an air gap. The pole is magnetically coupled to the magnetic element so that a magnetic flux is generated in the air gap substantially orthogonal to the axis of motion. A conductive coil is coiled around a coil axis and is fixed in relation to the stationary element with the coil axis substantially parallel to the axis of movement. The coil is in non-contact relation with the yoke and resides between the magnetic element and the pole of the yoke in the magnetic flux.

Abstract: A homopolar magnetic actuator is configured to exert controllable radial forces on a body adapted to rotate around an axis. The actuator comprises at least three radial magnetic pole assemblies distributed at some distances from each other along the axis, each including a plurality of poles adjacent to an actuator target on the body. Permanent magnets are used to induce bias magnetic fluxes in the assemblies with polarities alternating from assembly to assembly but remaining the same around the rotational axis. Having several small bias fluxes distributed between several pole assemblies instead of a large single bias flux facilitates designing an actuator with a high aspect ratio. A control coil around each pole can induce a control magnetic flux in the poles. These control fluxes affect magnetic flux distribution around the actuator target, resulting in magnetic forces exerted on the target.

Abstract: An electromagnetic actuator with flux feedback control includes two poles located on opposite sides of a soft-magnetic target. A bias flux is introduced that flows into both poles. Magnetic circuitry may be designed so that the total bias flux is independent or substantially independent of a position of the target with respect to the poles or the control flux. The electromagnetic actuator also includes flux sensors introduced into each gap between the poles and the target. The electromagnetic actuator further includes an actuator control circuit to command the current in the control coil to bring a difference between the readings of the two flux sensors to a targeted level. In some aspects, the force exerted on the actuator target in this arrangement may be proportional to the command signal regardless of the position of the actuator target, MMF drop in the soft-magnetic parts of the magnetic circuit, or the frequency.

Abstract: An electromagnetic actuator includes a body having a rotational axis, a first pole adjacent an end facing surface of the body, and a second pole adjacent a lateral facing surface of the body. The poles are adapted to communicate magnetic flux with the body. The body, the first pole, and the second pole define an axial magnetic control circuit. The actuator includes a plurality of radial poles adjacent the lateral facing surface of the body and adapted to communicate magnetic flux with the body. The body and the plurality of radial poles define a plurality of radial magnetic control circuits. The plurality of radial poles are adapted to communicate magnetic fluxes with the body and at least one of the first pole or the second pole. The body, the plurality of radial poles, and at least one of the first pole or the second pole define a magnetic bias circuit.

Abstract: An electromagnetic actuator includes a body having a rotational axis, a first pole adjacent an end facing surface of the body, and a second pole adjacent a lateral facing surface of the body. The poles are adapted to communicate magnetic flux with the body. The body, the first pole, and the second pole define an axial magnetic control circuit. The actuator includes a plurality of radial poles adjacent the lateral facing surface of the body and adapted to communicate magnetic flux with the body. The body and the plurality of radial poles define a plurality of radial magnetic control circuits. The plurality of radial poles are adapted to communicate magnetic fluxes with the body and at least one of the first pole or the second pole. The body, the plurality of radial poles, and at least one of the first pole or the second pole define a magnetic bias circuit.

Abstract: The proposed tool comprises a body (1) designed to interact with a percussion-rotary device and a casing (2) shaped as a sleeve. The casing (2) accommodates rock-crushing elements (5, 6) arranged in a manner allowing axial displacement thereof and in the form of concentric rows relative to a working end of the casing (2), the rock-crushing elements having shanks (7, 8) which interact with the body (1). Each rock-crushing element (6) in a peripheral row comprises a spring biased pin mechanism (16) for fixing the rock-crushing element (6) in the casing (2). The casing includes a threaded joint (9) for its axial displacement relative to the body (1). The length of axial displacement of the casing (2) relative to the body (1) is at least equal to the length (H) of the wearable portion of the rock-crushing elements (5, 6).