A pole piece for a torque motor includes two separate arcuate members and first and second diametrically opposed attachment portions formed as a single piece of material. Each arcuate member extends in opposite directions from the first attachment portion and following a generally circular path defining a perimeter of the pole piece and meeting each other at the second attachment portion. The arcuate members are devoid of any holes or apertures.

A two degree-of-freedom motor includes a stator, a plurality of stator windings, a rotor, a shaft, a limited angle torque motor, and a spring. The stator has a main body and a plurality of stator poles. The stator windings are wound around the stator poles. The rotor is spaced apart from the stator and includes a plurality of magnets and is configured to rotate about a first rotational axis. The shaft is coupled to the rotor and is rotatable therewith and and has a shaft first end and a shaft second end. The limited angle torque motor is coupled to the shaft first end, and is operable to supply a torque that causes the shaft, the rotor, and the stator to rotate about a second rotational axis that is perpendicular to the first rotational axis. The spring is fixedly mounted and is coupled to the limited angle torque motor.

A two degree-of-freedom motor includes a stator, a plurality of stator windings, a rotor, a shaft, a limited angle torque motor, and a spring. The stator has a main body and a plurality of stator poles. The stator windings are wound around the stator poles. The rotor is spaced apart from the stator and includes a plurality of magnets and is configured to rotate about a first rotational axis. The shaft is coupled to the rotor and is rotatable therewith and and has a shaft first end and a shaft second end. The limited angle torque motor is coupled to the shaft first end, and is operable to supply a torque that causes the shaft, the rotor, and the stator to rotate about a second rotational axis that is perpendicular to the first rotational axis. The spring is fixedly mounted and is coupled to the limited angle torque motor.

A cooling system of an internal combustion engine includes a control valve that regulates the flow of a coolant in a circulation circuit, and an electronic control unit. The electronic control unit is configured to have the following functions: controlling the driving of a motor of the control valve; calculating a motor torque based on an effective voltage applied to the motor; calculating a valve body torque that is part of the motor torque, based on an angular acceleration rate of the motor; and calculating a driving stress based on a difference between the motor torque and the valve body torque.

A cooling system of an internal combustion engine includes a control valve that regulates the flow of a coolant in a circulation circuit, and an electronic control unit. The electronic control unit is configured to have the following functions: controlling the driving of a motor of the control valve; calculating a motor torque based on an effective voltage applied to the motor; calculating a valve body torque that is part of the motor torque, based on an angular acceleration rate of the motor; and calculating a driving stress based on a difference between the motor torque and the valve body torque.

There is provided a pole-piece for a torque motor, the pole-piece comprising a first section formed separate from a second section, wherein the first section and the second section are configured to abut each other to form one or more lines of abutment on an outer surface thereof, and each line of abutment follows an S- or Z-shape when the first section abuts the second section.

There is provided a pole-piece for a torque motor, the pole-piece comprising a first section formed separate from a second section, wherein the first section and the second section are configured to abut each other to form one or more lines of abutment on an outer surface thereof, and each line of abutment follows an S- or Z-shape when the first section abuts the second section.

A torque motor for use in a servovalve wherein only two holes must be provided through each of the pole pieces in order to assemble the torque motor together. The torque motor comprises first and second opposing pole pieces, first and second permanent magnets positioned between the first and second pole pieces; an armature comprising a magnetic plate and a flapper, the magnetic plate being positioned between the first and second permanent magnets, the flapper being connected at one end to the magnetic plate; and further comprising: first and second fastening means each extending through the first pole piece, the armature and the second pole piece to thereby fasten the torque motor together.

A torque motor for use in a servovalve wherein only two holes must be provided through each of the pole pieces in order to assemble the torque motor together. The torque motor comprises first and second opposing pole pieces, first and second permanent magnets positioned between the first and second pole pieces; an armature comprising a magnetic plate and a flapper, the magnetic plate being positioned between the first and second permanent magnets, the flapper being connected at one end to the magnetic plate; and further comprising: first and second fastening means each extending through the first pole piece, the armature and the second pole piece to thereby fasten the torque motor together.

A torque motor assembly comprising two or more pole piece pairs, each pair comprising two opposing pole pieces each having an end facing an end of the opposite pole piece, the ends separated by a gap; and a magnetic plate extending between the pole piece pairs and located in the gap, the magnetic plate having surface portions facing the respective pole piece ends; wherein the surface portions of the magnetic plate and the respective pole piece ends are non-parallel with respect to each other.