An insert for a bed plate according to an embodiment of the present disclosure is coupled to a lower portion of an engine block. The insert of the bed plate includes a crankshaft seating portion disposed at a center and where a crankshaft is mounted. The insert of the bed plate also includes a ladder frame fixing portions that are disposed at opposite ends of the insert to facilitate coupling to a ladder frame. The insert of the bed plate also includes a plurality of protrusion portions that are formed on both surfaces of the insert and contact the ladder frame.

A balance shaft is proposed that includes: i) an unbalance shaft having an unbalance section and an adjacent bearing pin having a cylindrical partial circumference which is oriented towards the shaft imbalance; ii) a bearing ring which surrounds the bearing pin and bears against the cylindrical partial circumference and delimits a free space with a bearing pin back radially opposite thereto; and, iii) a clamping element which is clamped in the free space and clamps the bearing ring radially against the cylindrical partial circumference. The clamping element is intended to secure the bearing ring against axial sliding on both sides on the bearing pin, and the clamping element is connected in an axially interlocking manner to the unbalance shaft on one side and to the bearing ring on the other side.

An unbalanced shaft is provided that has a center of mass eccentric to its rotational axis to generate a shaft unbalance. The unbalanced shaft includes a bearing journal having a variable width throughout its circumference, and a multi-row cage having rollers which roll on inner raceways arranged on an outer lateral surface of the bearing journal. The rollers and inner raceways define a load zone, within which a width of each of the inner raceways is greater than an effective length of the rollers idling thereon. At least one of the inner raceways, which extends circumferentially for 360 degrees, has a width throughout that is greater than an effective length of the rollers rolling thereon. For sections outside of the load zone, at least one of the inner raceways has a width less than the effective length of the rollers that roll thereon.

A balance shaft is proposed that includes: i) an unbalance shaft having an unbalance section and an adjacent bearing pin having a cylindrical partial circumference which is oriented towards the shaft imbalance; ii) a bearing ring which surrounds the bearing pin and bears against the cylindrical partial circumference and delimits a free space with a bearing pin back radially opposite thereto; and, iii) a clamping element which is clamped in the free space and clamps the bearing ring radially against the cylindrical partial circumference. The clamping element is intended to secure the bearing ring against axial sliding on both sides on the bearing pin, and the clamping element is connected in an axially interlocking manner to the unbalance shaft on one side and to the bearing ring on the other side.

A bearing assembly comprising a rotating shaft, a rolling bearing and a scissors gear. The bearing assembly further comprises an axial retaining arrangement for the scissors gear onto the rolling bearing. A lock washer is arranged in a groove of an outer massive ring of the rolling bearing.

A balance shaft support structure includes a bearing portion coupled with a cylinder block, and a rubber damper interposed between the bearing portion and a balance shaft journal to prevent vibration transmission of the balance shaft.

Balancer device has upper and lower housings 3 and 4 having therein an accommodation section 10, a pair of drive and driven side shafts 5 and 6 which are rotatably supported by four plain bearings 11 to 14 provided in the accommodation section and to which a rotation force is transmitted from a crankshaft, and arc band-shaped thrust receiving portions 32a and 33a which thrust flange portions of drive and driven gears 8 and 9 provided at the drive and driven side shafts respectively can contact from a thrust direction. First and second oil storing grooves 34 and 35, groove passages 36 and 37 and vertical groove passages 38a to 39b are formed at the thrust receiving portions on a gravity direction lower side with respect to a meshing portion of the both gears. With this configuration, it is possible to suppress occurrence of abrasion of the thrust receiving portion.

An internal combustion engine includes: a wall body that is formed on a crankcase to accommodate a generator by sandwiching the generator between the wall body and a generator cover coupled to the crankcase from outside; a casing that includes a casing wall, the casing wall being formed on the crankcase and, at a position apart from the wall body in an axial direction of the crankshaft, facing the wall body with a space contiguous to an outer surface of the crankcase sandwiched between the casing wall and the wall body; and a balancer shaft that has an axis thereof parallel to the rotation axis of the crankshaft, and is rotatably supported by the casing while one end of the balancer shaft protrudes from the casing wall into the space. Accordingly, the engine can reduce its weight by shortening the balancer shaft as much as possible without upsetting weight balance.

Balancer shaft 5 and 6 rotatably set through bearings 1114 and an oil pump 2 driven by power from the balancer shaft 5 and 6 are provided in a balancer housing. Oil discharged from an outlet portion 42 of the oil pump 2 is supplied to a main oil gallery 10 through an outlet passage 48. A bearing filter 55 that filters a part of the oil is provided in the outlet passage 48 that extends from the outlet portion 42. A communication passage 50 that branches off from the outlet passage 48 and communicates with the bearings 1114 supplies a part of the oil having been filtered by the bearing filter 55 to the bearings 1114. By filtering the oil that is going to be supplied to the bearing portion, decrease in durability of the bearing portion can be suppressed.

A balance weight having one or more journals with a reduced mass portion disposed between a pair of journal portions that define circumferentially extending bearing surfaces. The reduced mass portion has a body, which defines a circumferentially extending bearing surface that is concentric with the bearing surfaces on the journal portions, and at least one stiffening structure that is configured to resist flexing of the journal portions relative to one another due to the transmission of bending loads through the balance shaft.