A driving device including a drive shaft and a first engaging member. The drive shaft rotates around a first axis. The first engaging member is disposed on the first axis to rotate integrally with the drive shaft. The power transmission mechanism includes a second engaging member, a propeller shaft, a piston, and a reduction gear. The second engaging member is disposed on the first axis engageable with/disengageable from the first engaging member. The propeller shaft is rotatable integrally with the second engaging member around the first axis. The piston reciprocates the second engaging member between a first position and a second position along a direction of the first axis. The reduction gear is joined to the other end side of the propeller shaft to decelerate the rotation of the propeller shaft. The reduction gear causes an output shaft joined to an object to rotate around a second axis.

A rotary-member lubricating structure includes a housing, a baffle portion, a support portion, and a bolt. The baffle portion has a shape conforming to a shape of a rotary member included in a speed-changing mechanism and covers the rotary member to collect or discharge scattered lubricating oil. The baffle portion includes a first partial baffle portion provided on a first side of the rotary member and a second partial baffle portion provided on a second side of the rotary member. The first partial baffle portion has a protrusion protruding radially outward from an outer circumference of the baffle portion and a fastening hole provided in the protrusion and extending through the first partial baffle portion in an axial direction of the rotary member. The second partial baffle portion has a filling portion to fill a recess in the first partial baffle portion provided due to the protrusion.

A rotary-member lubricating structure includes a housing, a baffle portion, a support portion, and a bolt. The baffle portion has a shape conforming to a shape of a rotary member included in a speed-changing mechanism and covers the rotary member to collect or discharge scattered lubricating oil. The baffle portion includes a first partial baffle portion provided on a first side of the rotary member and a second partial baffle portion provided on a second side of the rotary member. The first partial baffle portion has a protrusion protruding radially outward from an outer circumference of the baffle portion and a fastening hole provided in the protrusion and extending through the first partial baffle portion in an axial direction of the rotary member. The second partial baffle portion has a filling portion to fill a recess in the first partial baffle portion provided due to the protrusion.

A motorcycle wherein only air can be communicated between the inside and the outside of a gear case without increasing the size of the gear case. A gear case includes a gear case body and a gear case cover. The gear case body includes a breather chamber of a labyrinth structure which continues in a circumferential direction of a rear wheel and extends in an upward and downward direction. An upper end of the breather chamber is in communication with a breather path and is open to atmospheric air while a lower end of the breather chamber is in communication with a gear chamber through a slit extending in a widthwise direction of the rear wheel.

A motorcycle wherein only air can be communicated between the inside and the outside of a gear case without increasing the size of the gear case. A gear case includes a gear case body and a gear case cover. The gear case body includes a breather chamber of a labyrinth structure which continues in a circumferential direction of a rear wheel and extends in an upward and downward direction. An upper end of the breather chamber is in communication with a breather path and is open to atmospheric air while a lower end of the breather chamber is in communication with a gear chamber through a slit extending in a widthwise direction of the rear wheel.

A drive force transmission device includes a frame that supports therein plural gears transmitting a rotational drive force and that has a flat portion extending in a direction intersecting a direction in which the rotational drive force is transmitted. The drive force transmission device has an air channel that allows air sucked from an outside of the frame to pass therethrough so as to exhaust the air to the outside of the frame.

A drive force transmission device includes a frame that supports therein plural gears transmitting a rotational drive force and that has a flat portion extending in a direction intersecting a direction in which the rotational drive force is transmitted. The drive force transmission device has an air channel that allows air sucked from an outside of the frame to pass therethrough so as to exhaust the air to the outside of the frame.

Provided is a technology whereby leakage of oil from inside a case to outside the case can be suppressed, as a result of including: a motor unit 100; a deceleration unit 200 that, as a result of having oil interposed therein, operates smoothly and decelerates the rotary speed of the motor unit 100; a case 400 that contains the deceleration unit 200; and a ventilation member 500 attached to the case 400 and having a ventilation membrane that captures oil moving from inside the case 400 towards outside the case 400 and also has multiple pores formed therein that permit a gas to flow between the inside and the outside.

Provided is a technology whereby leakage of oil from inside a case to outside the case can be suppressed, as a result of including: a motor unit 100; a deceleration unit 200 that, as a result of having oil interposed therein, operates smoothly and decelerates the rotary speed of the motor unit 100; a case 400 that contains the deceleration unit 200; and a ventilation member 500 attached to the case 400 and having a ventilation membrane that captures oil moving from inside the case 400 towards outside the case 400 and also has multiple pores formed therein that permit a gas to flow between the inside and the outside.

Some embodiments of a gearbox for an irrigation system can comprise a housing, a worm gear within the housing, a bull gear within the housing and configured to be engaged with the worm gear, a diaphragm, and a vent. The diaphragm can define a chamber configured for expansion and contraction and configured to be positioned inside the housing to relieve pressure build-up within the housing. The vent can be configured to allow air to flow between the atmosphere and the chamber.