Motor unit

1. A motor unit comprising:

a motor;

a housing including a housing space to house the motor;

oil in a vertically lower region of the housing space; and

an oil passage to lead the oil from the vertically lower region of the housing space through the motor to the vertically lower region of the housing space; wherein

the oil passage includes a first oil passage extending through an inside of the motor, and a second oil passage extending through an outside of the motor;

one of the first oil passage and the second oil passage includes a cooler to cool the oil therein;

the housing space of the housing is divided into a motor chamber and a gear chamber by a partition;

an oil pool is provided at a bottom portion of the gear chamber;

in the first oil passage, oil contained in the oil pool is drawn up by a gear, fed to a shaft of the motor, and then returned to the oil pool; and

in the second oil passage, oil contained in the oil pool is suctioned to an upper side of the motor, fed to the motor, and then returned to the oil pool.

2. The motor unit according to claim 1 , wherein

each of the first oil passage and the second oil passage includes a circulation channel extending from the vertically lower region of the housing space back to the vertically lower region of the housing space through the motor; and

the first oil passage and the second oil passage are joined at the vertically lower region of the housing space.

3. The motor unit according to claim 1 , wherein the motor includes:

a rotor including the shaft extending along a motor axis, and a rotor core surrounding the shaft from radially outside, the rotor being rotatable about the motor axis; and

a stator radially outside of the rotor; and

the first oil passage includes a channel extending from an interior of the shaft through the rotor core.

4. The motor unit according to claim 3 , wherein

the gear is in the housing space and connected to the motor,

at least a portion of the gear is lower than a liquid surface of the oil in the vertically lower region of the housing space;

a channel of the first oil passage includes a first reservoir in the housing space; and

the first oil passage includes:

an oil flow passage to lead the oil from the first reservoir to the interior of the shaft; and

a scraping-up channel along which the oil in the vertically lower region of the housing space is scraped up by rotation of the gear to be received by the first reservoir.

5. The motor unit according to claim 1 , wherein the second oil passage is structured to feed the oil in the vertically lower region of the housing space to the motor through the upper side of the motor.

6. The motor unit according to claim 5 , wherein

a channel of the second oil passage includes a second reservoir to store the oil therein, the second reservoir being located on the upper side of the motor; and

the second reservoir includes an outflow port to feed a portion of the oil in the second reservoir to the motor.

7. The motor unit according to claim 5 , wherein a channel of the second oil passage includes a pump and the oil cooler therein, the pump and the cooler being arranged one under another in an up-down direction, each of the pump and the cooler being fixed to an outer peripheral surface of the housing.

8. The motor unit according to claim 1 , wherein

the second oil passage includes a pump, a first flow passage, a second flow passage, and a third flow passage;

the first flow passage connects the oil pool and the pump to each other;

the first flow passage a includes a first end portion and a second end portion, the first end portion opens into the housing space at a position below the gear.