Since a shape of a stator 44 is made mirror symmetric with respect to a rotor 45 as a 4-pole/6-slot type, rotational deflection of the rotor 45 can be suppressed. As the minimum number of poles and the minimum number of slots, which can suppress the rotational deflection of the rotor 45, a frequency of magnetic noises approaches a frequency of mechanical noises. Thus, it is possible to integrate the whole noises generated by the DR-side wiper motor 21 into a low frequency range thereof, and to make the acoustic sensitivity (dB) of a vehicle interior smaller. Since the stator 44 is fixed inside a housing 40 and mounting legs fixed to a vehicle body fixed portion are provided in the housing 40, the stator 40, which is a source of the magnetic noises, can be fixed to a vehicle via only the housing 40. Therefore, a brushless wiper motor with quietness improved further can be designed.

A method and system for monitoring operation of a motor may include initially determining a no load torque versus temperature characteristic of the motor over a range of operating temperatures. After a period of operation, a no load torque value and temperature of the motor may be determined. Motor temperature may be measured by a local thermistor or the like. Motor torque may be determined from measured motor current. The motor torque and temperature may then be compared to the initial torque versus temperature characteristic to determine a change in load of said motor due to break down of motor oil, worn bearings, or similar condition. In some embodiment, the method and system may be used with a downhole tool for drilling a well, such as a rotary steerable system.

A drive unit, especially an actuator unit in a vehicle, comprises an electric drive motor the motor shaft of which is rotatably mounted in bearings. A clamping ring is arranged in a housing and axially supports a bearing of the motor shaft.

A first support member and a second support member are provided in a rotation support device and a worm gear is rotated in a state that the second support member is inserted in the first support member, whereby the worm gear is prevented from being shaken through the first support member and the second support member and heat transmission to a housing due to rotation of the worm gear to damage the housing is prevented.

A drive apparatus includes a housing, an electric motor arranged in the housing, and a worm gear mechanism arranged in the housing. The worm gear mechanism includes a worm gear arranged on a rotor shaft of the electric motor and a gearwheel in engagement with the worm gear and fixedly connected to an output shaft so as to rotate with the output shaft. The electric motor is axially mounted in the housing with one axial end via a stop element and with the opposite axial end via an axial clamping element. The axial clamping element has a spring element, a separate floating holding element, and a separate elastomer element. The holding element is arranged axially between the spring element and the elastomer element.

Since a shape of a stator 44 is made mirror symmetric with respect to a rotor 45 as a 4-pole/6-slot type, rotational deflection of the rotor 45 can be suppressed. As the minimum number of poles and the minimum number of slots, which can suppress the rotational deflection of the rotor 45, a frequency of magnetic noises approaches a frequency of mechanical noises. Thus, it is possible to integrate the whole noises generated by the DR-side wiper motor 21 into a low frequency range thereof, and to make the acoustic sensitivity (dB) of a vehicle interior smaller. Since the stator 44 is fixed inside a housing 40 and mounting legs fixed to a vehicle body fixed portion are provided in the housing 40, the stator 40, which is a source of the magnetic noises, can be fixed to a vehicle via only the housing 40. Therefore, a brushless wiper motor with quietness improved further can be designed.

A motor device may include a motor comprising a motor shaft protruded from a motor main body; a worm gear connected with the motor shaft through a coupling; a worm wheel engaged with the worm gear; and a frame on which the motor, the worm gear and the worm wheel are mounted. The coupling may include a motor side coupling part; a transmission member; and a worm gear side coupling part. The motor side coupling part and the transmission member may be relatively movable in a first direction perpendicular to the axial line direction. The transmission member and the worm gear side coupling part may be relatively movable in a second direction perpendicular to the axial line direction and intersecting the first direction. A compression coil spring may be disposed between the transmission member and an end part of the worm gear.

The present invention relates to a speed reducer for a vehicle. The speed reducer includes: a gear housing configured to enclose a worm wheel and a worm shaft and including one of a first magnetic member and a second magnetic member, which generate attractive force or repulsive force therebetween as current is applied to a position facing the worm shaft in an axial direction; a first bearing coupled to an end of the worm shaft at an opposite side to a motor shaft-coupling portion; and a moving member coupled, at one side thereof, to an outer race of the first bearing and including, at a remaining side thereof, a remaining one of the first and second magnetic members, so that the moving member is axially moved according to the attractive force or the repulsive force.

A motor device may include a motor including a motor shaft protruded from a motor main body; a worm gear connected with the motor shaft through a transmission mechanism and is formed with a spiral groove; and a worm wheel engaged with the worm gear. The transmission mechanism may include a transmission member to transmit rotation of the motor shaft to the worm gear. One end face on the motor main body side of the worm gear and an end face on a worm gear side of the transmission member may be formed with two protruded parts protruded toward the other of the end faces, and a recessed part engaged with the protruded parts is formed in the other of the end faces. A compression coil spring may disposed between the worm gear and the transmission member between the two protruded parts.

An electric pipe expander and intelligent control circuit for the electric pipe expander are provided. The electric pipe expander includes a pipe expander body and a mandrel sliding cavity disposed on the pipe expander body. A chuck body capable of clamping a pipe to be processed is disposed at an opening end of the mandrel sliding cavity. A mandrel is slidingly connected in the mandrel sliding cavity, an outer side end of the mandrel is provided with an obliquely disposed pipe expanding cone, an inner side end of the mandrel is provided with an elastic body accommodating cavity. Flat keys are disposed on the mandrel, and an elastic body is clamped and disposed between the flat keys and a bottom surface of the elastic body accommodating cavity.