An electromagnetic actuator comprises: a pole tube, extending along a longitudinal axis so as to define an internal volume and having an external surface, the pole tube being made of a ferromagnetic material and including a magnetic separation region positioned at the external surface, along a circumference surrounding the longitudinal axis, the magnetic separation region defining a magnetic decoupling; an electromagnetic coil, surrounding the external surface of the pole tube; a stationary core, connected to the pole tube; a movable core, positioned in the internal volume and movable along the longitudinal axis, the electromagnetic actuator being characterized in that the magnetic separation region includes a plurality of recesses, angularly spaced to one another along the circumference, around the longitudinal axis.

A solenoid includes a coil portion and a yoke having a side surface portion along an axial direction so as to accommodate the coil portion. A gap in a radial direction that communicates a radial outside of a first magnetic flux transfer portion with an outside of the solenoid is formed between an inner surface of the side surface portion and an outer surface of the coil portion, and a protrusion is formed on at least one of an inner surface and an outer surface and protrudes in the radial direction to reduce a size of at least a part of the gap.

A non-magnetic member 32, a first magnetic member 34 and a second magnetic member 36 are prepared. The first magnetic member 34 and the second magnetic member 36 are connected to the non-magnetic member 32. Then, a first bonding portion 56 and which bonds the non-magnetic member 32 and the first magnetic member 34 to each other, and a second bonding portion 60 which bonds the non-magnetic member 32 and the second magnetic member 36 to each other are formed. A hot isostatic pressing process is performed to the non-magnetic member 32, the first magnetic member 34 and the second magnetic member 36 to establish diffusion-bond. Thereafter, the non-magnetic member 32, the first magnetic member 34 and the second magnetic member 36 are hollowed, and the first bonding portion 56 and the second bonding portion 60 are removed. Thereafter, the non-magnetic member 32 becomes a non-magnetic body 26, the first magnetic member 34 becomes a first magnetic body 28, the second magnetic member 36 becomes a second magnetic body 30 and a sleeve 10 is obtained.

A method for manufacturing a pole tube having two magnetic pole tube components and having one nonmagnetic ring, which is situated axially between the pole tube components, for an electromagnet, in particular for a solenoid valve of an automatic transmission in a motor vehicle, including the following: concentric configuration and/or centering of the pole tube components and of the ring, in particular on a centering pin; form-fitting connection, in particular by extrusion coating and/or casting an exterior lateral surface of the pole tube components and of the ring.

A method for manufacturing a pole tube having two magnetic pole tube components and having one nonmagnetic ring, which is situated axially between the pole tube components, for an electromagnet, in particular for a solenoid valve of an automatic transmission in a motor vehicle, including the following: concentric configuration and/or centering of the pole tube components and of the ring, in particular on a centering pin; form-fitting connection, in particular by extrusion coating and/or casting an exterior lateral surface of the pole tube components and of the ring.

A solenoid valve includes a valve portion and a solenoid portion. The valve portion has a sleeve and a valve body inserted into the sleeve. The solenoid portion includes a stator core having a magnetic attraction core, a sliding core, a magnetic flux passage suppressing portion that suppresses the passage of magnetic flux between the sliding core and the magnetic attraction core, a magnetic yoke, a coil portion, a plunger, and a magnetic tubular base portion. The base portion is fastened to a first outer peripheral surface of an end on the solenoid portion side in the axial direction of the sleeve, is arranged outside a radial direction of a second outer peripheral surface of the end on the valve portion side in the axial direction of the magnetic attraction core, and comes into contact with the yoke inside the yoke.

A method for manufacturing a magnetic valve and a corresponding magnetic valve, in particular for the use for electrically continuously adjustable shock absorbers of a vehicle. A valve housing and a magnetic armature which is movably supported relative to a longitudinal axis of an electrically energizable coil and which is at least partially surrounded by a pole tube which is at least partially surrounded by a coil body of the coil that in turn is cast with a casting compound, provides a corrosion protection cap covering an axial end of the pole tube. The corrosion protection cap establishing a connection to the casting compound and protecting the axial end of the pole tube against corrosion influences from the atmosphere.

An electromagnetic actuator having a unitary pole piece arranged within and coupled to a housing is provided. The housing is coupled to the unitary pole piece such that a load on the unitary pole piece is reduced during assembly and/or installation of the electromagnetic actuator. The unitary pole piece is structured to reduce leakage past an armature slidably received within the pole piece.

A solenoid includes a coil defining an axis, an armature disposed radially inward of the coil, and a plurality of linear guides disposed at least partially between a radially inward facing surface of the coil and a radially outward facing surface of the armature. Each of the linear guides has a frictional surface area, with a dimension of the frictional surface area aligned with the axis being larger than a dimension of the frictional surface area aligned with a circumference of the coil.

A solenoid actuator is provided that includes a casing. A coil is positioned within the casing. A flux tube and axially separated pole piece are encircled by the coil. An armature is slidably mounted within bores of the flux tube and pole piece. The flux tube and pole piece are separated by a flux choke. A core shunt juxtaposes the pole piece from the flux choke. The core shunt, on major cross-sectional tubular thickness and a minor cross-sectional tubular thickness has an outer diameter of a curved shunt to provide enhanced performance stability.