In an electric power steering device, a motor housing includes an end face part opposite to an output part of a rotating shaft of an electric motor. A power conversion circuit part includes a power conversion switching circuit part, and a second part exclusive of the power conversion switching circuit part. The power conversion switching circuit part includes an upper arm switching element and a lower arm switching element packaged by synthetic resin, and is mounted on a power conversion switching circuit board that is mounted to a power conversion switching circuit part heat dissipation section of the end face part for heat dissipation. A power supply circuit part and the second part of the power conversion circuit part are mounted on a power supply circuit board that is mounted to a power supply circuit part heat dissipation section of the end face part for heat dissipation.

In an electric power steering device, a motor housing includes an end face part opposite to an output part of a rotating shaft of an electric motor. A power conversion circuit part includes a power conversion switching circuit part, and a second part exclusive of the power conversion switching circuit part. The power conversion switching circuit part includes an upper arm switching element and a lower arm switching element packaged by synthetic resin, and is mounted on a power conversion switching circuit board that is mounted to a power conversion switching circuit part heat dissipation section of the end face part for heat dissipation. A power supply circuit part and the second part of the power conversion circuit part are mounted on a power supply circuit board that is mounted to a power supply circuit part heat dissipation section of the end face part for heat dissipation.

A motor unit includes a case, a motor, an input shaft, an input body, an output body, and a speed reducer mechanism. The input shaft penetrates through the case in an axial direction and is arranged to be rotatable. The input body is disposed along an outer peripheral surface of the input shaft and rotates along with the input shaft. The output body is arranged along the outer peripheral surface of the input shaft to be rotatable and receives rotational force from the input body. The case includes a first bearing, a second bearing, and a third bearing. The first bearing is located at one end in an axial direction and supports a rotary shaft unit including the input shaft, the input body, and the output body. The second bearing is located at the other end in the axial direction and supports the rotary shaft unit. The third bearing is located between the first bearing and the second bearing in the axial direction and supports at least one of the input body or the output body.

A motor unit includes a case, a motor, an input shaft, an input body, an output body, and a speed reducer mechanism. The input shaft penetrates through the case in an axial direction and is arranged to be rotatable. The input body is disposed along an outer peripheral surface of the input shaft and rotates along with the input shaft. The output body is arranged along the outer peripheral surface of the input shaft to be rotatable and receives rotational force from the input body. The case includes a first bearing, a second bearing, and a third bearing. The first bearing is located at one end in an axial direction and supports a rotary shaft unit including the input shaft, the input body, and the output body. The second bearing is located at the other end in the axial direction and supports the rotary shaft unit. The third bearing is located between the first bearing and the second bearing in the axial direction and supports at least one of the input body or the output body.

A motor unit, which is an example of an embodiment, includes a motor including a motor shaft, a rotor fixed to the motor shaft, and a stator, and a control board, the control board being disposed with at least a part of the control board overlapping the motor when viewed in a motor axial direction. A sensor that detects a magnetic field of the motor shaft, the rotor, or a rotating body rotating together with the motor shaft, and a control element that controls the motor using detection information of the sensor, are mounted on the control board. The control board includes a signal line that connects the sensor and the control element. The signal line includes an arcuate wiring section bent to be convex in a radial direction outer side of a circle centering on a shaft core of the motor shaft.

A method of verifying torque measurements of a reaction torque transducer of an instrument drive unit includes a controller receiving a verification signal, generating an acceptable range of torques, receiving a torque signal, comparing the torque signal to the acceptable range of torques, and stopping a motor if the torque applied by the motor is outside of the acceptable range of torques. The verification signal is indicative of the current drawn by the motor and the torque signal is indicative of torque applied by the motor.

A method of verifying torque measurements of a reaction torque transducer of an instrument drive unit includes a controller receiving a verification signal, generating an acceptable range of torques, receiving a torque signal, comparing the torque signal to the acceptable range of torques, and stopping a motor if the torque applied by the motor is outside of the acceptable range of torques. The verification signal is indicative of the current drawn by the motor and the torque signal is indicative of torque applied by the motor.

An electric machine designed as a permanently excited synchronous machine, including a rotor with a rotor body arranged on a rotor shaft, a stator, and a displacement device that generates a relative axial movement between the rotor body and the stator based on a torque produced between the rotor shaft and the rotor body. The displacement device has first and second displacement elements and at least one rolling body arranged between the first and second displacement elements. The first displacement element is axially movable and rotatable to a limited degree on the rotor shaft, and the second displacement element is connected to the rotor shaft rotationally fixed. The displacement elements provide that upon rotation of the first displacement element relative to the second or vice versa, the rotor body is pushed on the rotor shaft axially against the spring force.

An electric radial flow machine having a stator, a rotor body connected to a rotor shaft, and a spring element which applies a spring force to the rotor body in the axial direction such that in a first operating position, the rotor body is held in an axial position in which the overlap between opposing surfaces of the rotor body and the stator is less than 100%. A displacement device with first and second displacement elements generates an axial movement between the rotor body and the stator against the spring force using a torque produced between the rotor shaft and the rotor body so that in the event of a rotation of the first displacement element relative to the second displacement element or vice versa, the rotor body is pushed on the rotor shaft axially against the spring force.

Air circulation passages connect an accommodation space of an electronic control unit to the outside to circulate air to buffer internal pressure fluctuations. The accommodation space side of the air circulation passages is formed as a divided air circulation passage with a plurality of passages, a cooling object member is arranged to come in thermal contact with air flowing through the divided air circulation passage, and the total cross-sectional area of the divided air circulation passage is smaller than the cross-sectional area of the air circulation passages that are not divided. Because the accommodation space of the electronic control unit is connected to the outside, internal pressure fluctuations can be buffered, and increasing the flow velocity of the air flowing through the divided air circulation passage on the accommodation space side of the air circulation passages allows heat inside the accommodation space to be efficiently radiated to the outside.