A translating actuator acting between two extreme positions defined by mechanical stops is described. Said actuator comprises: an armature mass movable relative to the armature body, a stiff armature spring set such that the natural resting position of the armature mass is close to the centre of travel between the two extreme positions and pair of latches with sufficient holding force that the armature mass can be held at either extreme position against the restoring force of the spring and can be released quickly relative to the natural period of vibration determined by the armature mass on the armature spring.

A valvetrain includes a rocker arm assembly having an electromagnetic latch housed in a chamber formed by a rocker arm. The chamber may be a retrofit hydraulic chamber. A flux shifting bi-stable latch provides a sufficiently compact design. Isolation of the magnetic elements within the rocker arm chamber may provide protection from metal particles carried by oil in an operating environment for the rocker arm assembly. Wiring connections to the rocker arms may be made through spring posts on the rocker arms. Connection to the rocker arms may be made with springs that can endure the rapid motion induced by the rocker arms. A wiring harness for the rocker arms may attach to hydraulic lash adjusters of the rocker arm assemblies. The rocker arm assemblies and their wiring may be formed into a unitary module that facilitates installation.

In one embodiment, an electromagnetic soft actuator includes a first soft outer member comprising a soft internal electrically conductive coil, a second soft outer member comprising a soft internal electrically conductive coil, and a soft inner shaft on which the first and second soft outer members are mounted, the first and second soft outer members being linearly displaceable along a length of the soft inner shaft, the soft inner shaft comprising a permanent magnet, wherein the first and second outer members linearly move under an electromagnetic force relative to the soft inner shaft and each other when an electric current is applied to the soft internal electrically conductive coils.

An actuator control system suitable for providing single wire control of electromagnetic latch assemblies providing for cylinder deactivation or variable valve actuation in a valvetrain system. The system is adapted to control electromagnetic latch assemblies that require DC current in a first direction for latching and DC current in a reverse of the first direction for unlatching. The actuator control system includes an inverting DC/DC converter and switching elements. In some embodiments, the inverting DC/DC converter uses capacitors to store energy that drives the inverted current. In some embodiments, the inverting DC/DC converter serves a plurality of distinct groups of the electromagnets.

In an electromagnetic latch assembly of a type that includes an armature, an electromagnet operative to actuate the armature, a latch pin, and a rigid metal structure that supports both the electromagnet and the latch pin, the latch pin is attached to the armature through a bendable connection. The electromagnet may be mounted to or housed within the metal structure. The latch pin may protrude from the rigid metal structure and may be guided by the metal structure. The bendable connection couples translation of the armature to translation of the latch pin while allowing the two parts to move independently to some degree. The bendable connection may reduce forces on the armature that could cause the armature to bend or stick. Those forces may result from misalignment between the latch pin and the armature or from the latch pin being driven off axis under load.

An actuator control system suitable for providing single wire control of electromagnetic latch assemblies providing for cylinder deactivation or variable valve actuation in a valvetrain system. The system is adapted to control electromagnetic latch assemblies that require DC current in a first direction for latching and DC current in a reverse of the first direction for unlatching. The actuator control system includes an inverting DC/DC converter and switching elements. In some embodiments, the inverting DC/DC converter uses capacitors to store energy that drives the inverted current. In some embodiments, the inverting DC/DC converter serves a plurality of distinct groups of the electromagnets.

In an electromagnetic latch assembly of a type that includes an armature, an electromagnet operative to actuate the armature, a latch pin, and a rigid metal structure that supports both the electromagnet and the latch pin, the latch pin is attached to the armature through a bendable connection. The electromagnet may be mounted to or housed within the metal structure. The latch pin may protrude from the rigid metal structure and may be guided by the metal structure. The bendable connection couples translation of the armature to translation of the latch pin while allowing the two parts to move independently to some degree. The bendable connection may reduce forces on the armature that could cause the armature to bend or stick. Those forces may result from misalignment between the latch pin and the armature or from the latch pin being driven off axis under load.

In one embodiment, an electromagnetic soft actuator includes a first soft outer member comprising a soft internal electrically conductive coil, a second soft outer member comprising a soft internal electrically conductive coil, and a soft inner shaft on which the first and second soft outer members are mounted, the first and second soft outer members being linearly displaceable along a length of the soft inner shaft, the soft inner shaft comprising a permanent magnet, wherein the first and second outer members linearly move under an electromagnetic force relative to the soft inner shaft and each other when an electric current is applied to the soft internal electrically conductive coils.

A valvetrain includes a rocker arm assembly having an electromagnetic latch housed in a chamber formed by a rocker arm. The chamber may be a retrofit hydraulic chamber. A flux shifting bi-stable latch provides a sufficiently compact design. Isolation of the magnetic elements within the rocker arm chamber may provide protection from metal particles carried by oil in an operating environment for the rocker arm assembly. Wiring connections to the rocker arms may be made through spring posts on the rocker arms. Connection to the rocker arms may be made with springs that can endure the rapid motion induced by the rocker arms. A wiring harness for the rocker arms may attach to hydraulic lash adjusters of the rocker arm assemblies. The rocker arm assemblies and their wiring may be formed into a unitary module that facilitates installation.

An electromagnetic actuator is provided in which a mobile member is designed to slide inside a ferromagnetic frame along a displacement axis X-X between two end positions, when exposed to a magnetic flux circulating in said frame. The frame forms a magnetic circuit that extends in a single loop interrupted by two air gaps, each placed on the displacement axis of the mobile member. At the air gaps the flux generates two transverse magnetic fields in opposite directions. The mobile member includes a permanent magnet, polarized in a pre-determined direction and having an axial dimension such that in each end position, one end of the magnet extends into one of the air gaps and the opposite end of the magnet extends into the other air gap.