Electric power steering apparatus

An electric power steering apparatus, comprising:

• an electric motor rotatable in response to steering operation;
• a drive torque transmission mechanism for converting a rotation of the electric motor to a linear movement and transmitting the linear movement to vehicle wheels for steering of the vehicle wheels;
• a first circuit board mounting thereon a processing element to process a control command for rotation control of the electric motor;
• a second circuit board mounting thereon a driving element to drive the electric motor based on the control command from the first circuit board;
• a metal control housing accommodating therein the first and second circuit boards and coupled at an outer surface thereof to the drive torque transmission mechanism;
• a heat transfer part provided as a separator wall between the electric motor and the at least one of the first and second circuit boards, the separator wall having an insulator gap between opposing first and second sides thereof, such that heat is transferred from the at least one of the first and second circuit boards to the first side of the heat transfer part, and heat is transferred from the electric motor to the second side of the heat transfer part;
• and
• a heat guide part extending from the heat transfer part through to the outer surface of the metal control housing coupled to the drive torque transmission mechanism, so as to guide the heat transferred to the heat transfer part in a direction toward the drive torque transmission mechanism.

An electric power steering apparatus, comprising:

• an electric motor rotatable in response to steering operation;
• a drive torque transmission mechanism for converting a rotation of the electric motor to a linear movement and transmitting the linear movement to vehicle wheels for steering of the vehicle wheels;
• at least one circuit board mounting thereon a processing element to process a control command for rotation control of, and a driving element to drive, the electric motor;
• a metal control housing accommodating therein the at least one circuit board, and coupled at an outer surface thereof to the drive torque transmission mechanism;
• a heat transfer part provided as a separator wall between the electric motor and the at least one circuit board, the separator wall having an insulator gap between opposing first and second sides thereof, such that heat is transferred from the at least one circuit board to the first side of the heat transfer part, and heat is transferred from the electric motor to the second side of the heat transfer part;
• and
• a heat guide part extending from the heat transfer part through to the outer surface of the metal control housing coupled to the drive torque transmission mechanism, so as to guide the heat transferred to the heat transfer part in a direction toward the drive torque transmission mechanism.