A system for a vehicle differential includes a magnetic field generator, a drive member and a lock member. The drive member is movable in response to a magnetic field between a first position and a second position, and the drive member has at least one contact surface. The lock member adjacent to the drive member and having at least one contact surface that is engaged by at least one contact surface of the drive member so that the lock member is driven by the drive member to engage a gear of the differential when the drive member is in the second position, and the lock member is adapted to be disengaged from the gear when the drive member is in the first position. One or both of the drive member and the lock member has at least one contact surface that is discontinuous.

A driving force transmission control apparatus includes: a driving force transmission device that includes an electromagnetic clutch mechanism configured to generate a frictional force between clutch plates by energization of an electromagnetic coil and transmits a driving force by actuating the electromagnetic clutch mechanism; and a control device that controls the driving force transmission device. The control device includes a storage unit storing a hysteresis value representing the difference between a current value required to transmit a predetermined torque when an energization current to the electromagnetic coil is gradually increased and a current value required to transmit the predetermined torque when the energization current is gradually reduced, a torque command value calculator that calculates a torque command value, and a current command value calculator that calculates a current command value representing a target value of a current to be supplied to the electromagnetic coil based on the torque command value and the hysteresis value.

A magnetic actuator includes a first element and a second element movable with respect to the first element in a movement direction. The first element includes teeth successively in the movement direction, two coils in slots defined by the teeth, and a permanent magnet. The second element includes teeth successively in the movement direction. The teeth of the first and second elements and the permanent magnet are arranged so that the second element is held by magnetic forces in each of three positions also when there are no currents in the coils. The second element can be moved between the three positions by supplying electric currents to the coils. Thus, the second element is held in any of the three positions also when current supply to the magnetic actuator is unintentionally lost.

A magnetic clutch device having improved durability and reliability without increasing a size in an axial direction. A fixed member, the first engagement element, and a second engagement element are arranged concentrically to one another in order from a rotational center axis. The first engagement element comprises a first magnet. The fixed member comprises a second magnet in which a polarity is switched between a straight polarity and a reversed polarity, and a coil that switches the polarity of the second magnet depending on a direction of the current applied thereto.

An interrupter includes: an intermittent member having a meshing tooth meshing with a second rotary member, and moving in an axial direction between a coupled position and an uncoupled position; and an actuator making the intermittent member move in the axial direction. The actuator includes: a coil generating magnetic flux; and a plunger moving with the intermittent member in the axial direction. The plunger is disposed in a manner capable of making relative rotation to one of the first and second rotary members via first and second air gaps. When the coil is energized, the magnetic flux is introduced to the plunger from one of the first and second air gaps, the magnetic flux is led out of the plunger to the other air gap, and the plunger moves in the axial direction so as to reduce at least one air gap of the first and second air gaps.

An example electromagnetic clutch assembly includes a rotatable portion and a stationary portion. The rotatable portion includes a field winding and a clutch body, and the stationary portion includes an exciter winding that is inductively coupled to the rotatable portion and is operable to energize the field winding. The field winding is operable, when energized, to provide a magnetic field that causes engagement or disengagement between the clutch body and an armature body. A method of operating an electromagnetic clutch assembly is also disclosed.

A differential includes a clutch ring and an actuator. The clutch ring restricts rotation of a first side gear relative to a differential case. The actuator axially moves the clutch ring. The actuator includes an electromagnetic coil, a yoke, and an armature. The armature slides on an outer peripheral surface of the electromagnetic coil so as to move axially. The yoke includes a side wall facing an axial end face of the electromagnetic coil. At least one of an outer peripheral surface of the side wall and an inner peripheral surface of a cylindrical portion of the armature is provided with an inclined portion to prevent one of the outer peripheral surface and the inner peripheral surface from coming into contact with the other one of the outer peripheral surface and the inner peripheral surface.

A solenoid assembly is provided that includes male and female plungers and an electromagnetic coil configured to be energized to create a magnetic flux. Each plunger has a plunger face, where the female plunger face is configured to correspond with the male plunger face. The male plunger has a plurality of angled plunger steps that define the male plunger face, each angled plunger step including a corner having an angle in the range of 95 degrees to 115 degrees. The female plunger face has a similar, corresponding angled face. The solenoid assembly is suitable for use as a long stroke linear solenoid.

An electromagnetic connecting device includes a flange of a hub, an armature supported by the flange via a leaf spring, a rotor accommodating an electromagnetic coil, and an anti-vibration member. When an electric current is supplied to the electromagnetic coil, the armature moves in the axial direction of the hub against the spring force of the leaf spring, and is attracted to the rotor. The leaf spring includes a moving portion that moves in the axial direction together with the movement of the armature. The anti-vibration member is fixed to the moving portion of the leaf spring. The anti-vibration member includes a stopper that comes in contact with the flange, and a damper that comes in contact with the armature. With this configuration, an electromagnetic connecting device capable of reducing an impact sound both when the armature is attracted and released can be manufactured at a low manufacturing cost.

A power transmission device includes an armature that is shaped into a circular ring form. The armature is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. The armature-side friction surface has a plurality of grooves, each of which extends from a radially inner end portion of the armature-side friction surface to a location that is on a radially inner side of a radially outer end portion of the armature-side friction surface.