US 6,763,789 B1 · Electromagnetic actuator with permanent magnet

Abstract

A system and method for increasing force density of a valve actuator particularly suited for use in actuation of intake and/or exhaust valves of an internal combustion engine include at least one electromagnet having a coil wound about a core, and an armature fixed to an armature shaft extending axially through the coil and the core, and axially movable relative thereto. The actuator includes a flux generator, such as at least one permanent magnet positioned between the coil and the armature, oriented so that magnetic flux of the generator travels in a direction opposite to magnetic flux produced by the coil through the core during coil energization to reduce saturation of the core, but in the same direction as the magnetic flux produced by the coil through the armature, to increase an attractive force between the armature and the electromagnet, resulting in an actuator with an increased force density.

Claims22

Dependent claims

A valve actuator for an internal combustion engine, comprising:

at least one electromagnet having a coil wound about a core;
an armature fixed to an armature shaft extending axially through the coil and the core, and axially movable relative thereto;
and
at least one permanent magnet extending between the coil and the armature, wherein the at least one permanent magnet is oriented so that associated magnetic flux travels in a direction opposite to magnetic flux generated by the coil through the core to reduce saturation of the core during energization of the coil, but in the same direction as the magnetic flux generated by the coil through the armature, to increase an attractive force between the armature and the electromagnet.

1 more element

A valve actuator assembly for actuation of an internal combustion engine intake or exhaust valve, the valve actuator assembly comprising:

an upper electromagnet having an upper coil wound about an upper core;
a lower electromagnet having a lower coil wound about a lower core;
an armature fixed to an armature shaft, the armature shaft extending axially through the upper and lower coils and axially movable relative thereto;
at least one upper permanent magnet disposed within a corresponding slot of the upper core and extending between the upper coil and the armature;
an upper spring for biasing the armature shaft away from the upper electromagnet when the upper coil is de-energized;
at least one lower permanent magnet disposed within a corresponding slot of the lower core and extending between the lower coil and the armature;
and
a lower spring for biasing the armature shaft away from the lower electromagnet when the lower coil is de-energized.

5 more elements

Dependencies are inferred from the claim text.

Electromagnetic actuator with permanent magnet

Life of this patent

Electromagnetic actuator with permanent magnet

Life of this patent

Abstract

Claims22