A tool to facilitate alignment and synchronization of an internal combustion engine oil pump drive shaft and distributor. In a preferred embodiment, the tool is a tubular shaped shaft having cross pieces arranged in both ends of the shaft to facilitate such alignment.

An oil supply structure of a water-cooled internal combustion engine includes an oil cooler for improving oil circulation efficiency by making an oil passage of a lubrication system short. In addition, weight of the oil cooler is reduced by reducing the number of parts. The oil supply structure of a water-cooled internal combustion engine includes an oil pump drive shaft of an oil pump that is coaxially coupled with one end of a balancer shaft placed parallel with a crankshaft and a water pump drive shaft of a water pump that is coaxially coupled with the other end of the balancer shaft. In the oil supply structure, an oil cooler is provided in the vicinity of the oil pump together with an oil filter.

A balancer apparatus equipped with an oil pump includes a pump housing including a pump containing chamber provided therein, a pump forming member contained in the pump containing chamber and configured to discharge oil introduced from an intake portion from a discharge portion to an oil passage of the internal combustion engine when a rotational force is transmitted thereto, a control oil chamber provided between the pump containing chamber and the pump forming member in a radial direction with respect to a rotational axis of the pump forming member and configured to change a hydraulic pressure of the oil to be discharged from the pump forming member with the aid of the oil introduced therein after being discharged from the discharge portion, passing through an oil passage of the internal combustion engine, and being subjected to a pressure adjustment, and a balancer housing including a bearing retainer portion configured to transmit the rotational force from the internal combustion engine to the pump forming member. The bearing retainer portion supports a balancer shaft disposed along the rotational axis of the pump forming member. The balancer housing is attached to the pump housing in a direction of the rotational axis of the pump forming member. The balancer apparatus equipped with the oil pump further includes a plurality of oil passage opening portions formed together on one side surface of the balancer housing and each connected to an oil passage connected to a main oil gallery of the internal combustion engine. The plurality of oil passage opening portions includes a discharge oil passage opening portion of a discharge oil passage connecting the discharge portion and the main oil gallery of the internal combustion engine to each other, a feedback oil passage opening portion of a feedback oil passage connecting the main oil gallery of the internal combustion engine and the control oil chamber to each other, and a bearing oil passage opening portion of a bearing oil passage connecting the main oil gallery of the internal combustion engine and the bearing retainer portion to each other.

A balancer structure for an internal combustion engine and the internal combustion engine are provided. A transmission driving gear are arranged to be rotatable integrally with a crankshaft. A transmission driven gear is arranged to be rotatable integrally with a first balance shaft. The transmission driven gear meshes with the transmission driving gear. A balancer driving gear is arranged to be rotatable integrally with the first balance shaft. A balancer driven gear is arranged to be rotatable integrally with the second balance shaft. The balancer driven gear meshes with the balancer driving gear. The first balance shaft includes an output portion. The output portion outputs torque to an engine-driven accessory.

Disclosed is a balancer device for an internal combustion engine, wherein: a pump mounting fixing part to which an oil pump is fixed is formed on an end surface of a lower housing member; a gear accommodation part in which a pump driving gear and a reduction gear are accommodated is provided between the oil pump and the pump mounting fixing part; a rigidity-reinforcing part in which an oil discharge passage is defined in communication with a discharge port of the oil pump is formed on the lower housing member so as to extend in a direction of extension of first and second balancer shafts on an outer side of the lower housing member; and a portion of the pump mounting fixing part formed on the end surface of the lower housing member and the rigidity-reinforcing part are made integral with each other.

A balancer apparatus equipped with an oil pump includes a pump housing including a pump containing chamber provided therein, a pump forming member contained in the pump containing chamber and configured to discharge oil introduced from an intake portion from a discharge portion to an oil passage of the internal combustion engine when a rotational force is transmitted thereto, a control oil chamber provided between the pump containing chamber and the pump forming member in a radial direction with respect to a rotational axis of the pump forming member and configured to change a hydraulic pressure of the oil to be discharged from the pump forming member with the aid of the oil introduced therein after being discharged from the discharge portion, passing through an oil passage of the internal combustion engine, and being subjected to a pressure adjustment, and a balancer housing including a bearing retainer portion configured to transmit the rotational force from the internal combustion engine to the pump forming member. The bearing retainer portion supports a balancer shaft disposed along the rotational axis of the pump forming member. The balancer housing is attached to the pump housing in a direction of the rotational axis of the pump forming member. The balancer apparatus equipped with the oil pump further includes a plurality of oil passage opening portions formed together on one side surface of the balancer housing and each connected to an oil passage connected to a main oil gallery of the internal combustion engine. The plurality of oil passage opening portions includes a discharge oil passage opening portion of a discharge oil passage connecting the discharge portion and the main oil gallery of the internal combustion engine to each other, a feedback oil passage opening portion of a feedback oil passage connecting the main oil gallery of the internal combustion engine and the control oil chamber to each other, and a bearing oil passage opening portion of a bearing oil passage connecting the main oil gallery of the internal combustion engine and the bearing retainer portion to each other.

A gear configured to rotate as a unit with a shaft, the gear includes: a plurality of annular grooves formed on both side surfaces of the gear in a direction of a rotation axis of the shaft, at least partially overlapped when viewed from the direction of the rotation axis, and at least partially overlapped in a radial direction with respect to the rotation axis.

Disclosed is a balancer device for an internal combustion engine, wherein: a pump mounting fixing part to which an oil pump is fixed is formed on an end surface of a lower housing member; a gear accommodation part in which a pump driving gear and a reduction gear are accommodated is provided between the oil pump and the pump mounting fixing part; a rigidity-reinforcing part in which an oil discharge passage is defined in communication with a discharge port of the oil pump is formed on the lower housing member so as to extend in a direction of extension of first and second balancer shafts on an outer side of the lower housing member; and a portion of the pump mounting fixing part formed on the end surface of the lower housing member and the rigidity-reinforcing part are made integral with each other.

Oil pump and oil pump-integrated balancer device each have a pump housing formed by housing body 31 and cover member 32, pump shaft 33 having driven side helical gear 43 at which thrust force occurs when transmitting rotation force and rotating a rotor by the rotation force provided from drive side helical gear 13 that is engaged with driven side helical gear 43, first and second thrust receiving portions 47, 46 formed close to hole edges of bearing holes 32a, 31a of the cover member and the housing body, and first and second thrust limiting portions 49, 48 provided at the driven side helical gear and the pump shaft, contacting the thrust receiving portions from axis direction and limiting thrust movement of the pump shaft. With this configuration, oil pump and oil pump-integrated balancer device which are capable of securing stable support of the pump shaft are provided.

There is provided a balancer device for an internal combustion engine that suppresses lubricating oil from failing onto a reduction gear and a pump drive gear provided to drive and rotate an oil pump and thereby suppresses an increase in resistance against rotation between the reduction gear and the pump drive gear. The balancer device for the internal combustion engine includes a lower side housing on which a balancer drive gear, a first balancer shaft including a first balance weight, a first gear, a second gear, a second balancer shaft including a second balance weight, and the reduction gear are mounted. The balancer device also includes an upper side housing formed in such a shape that covers the balancer drive gear, the first balancer shaft including the first balance weight, the first gear, the second gear, the second balancer shaft including the second balance weight, the reduction gear, and the pump drive gear from above in the state that the oil pump is assembled with the upper side housing such that the pump drive gear is meshed with the reduction gear. The upper side housing is assembled with the lower side housing. The balancer device further includes an exposure opening formed in the upper side housing such that only the balancer drive gear is exposed from the upper side housing to be meshed with an engine-side gear.