Embodiments are directed toward an engine. In some embodiments, the engine includes a water pump and a balancer shaft. In some embodiments, the water pump has a plain bearing. In some embodiments, plain bearing is supplied with pressurized oil. In some embodiments, the balancer shaft drives the water pump as well as cam shafts.

Embodiments are directed toward an engine. In some embodiments, the engine includes a water pump and a balancer shaft. In some embodiments, the water pump has a plain bearing. In some embodiments, plain bearing is supplied with pressurized oil. In some embodiments, the balancer shaft drives the water pump as well as cam shafts.

The provided is a bearing device for a crankshaft of an internal combustion engine including: a crankshaft having a plurality of journal portions; main bearings for supporting the crankshaft; and a bearing housing, wherein a range in which the oil groove of the upper-side halved bearing of the second main bearing is formed in the circumferential direction includes at least a range of a circumferential angle of 20° within the ±45° region, a circumferential end portion of the oil groove on a rotationally forward side communicates with the crush relief at a minimum, and is open to a circumferential end face at a maximum, and a circumferential end portion of the oil groove on the rotationally backward side of the journal portion is positioned on a circumferential center portion side of the upper-side halved bearing from a circumferential end face of the upper-side halved bearing.

Systems and methods are described for a reciprocating mechanism. The system includes at least one axially translating y-axis component configured to reciprocate substantially along a y-axis with a reciprocating motion of a piston assembly relative to a base. The system also includes at least one x-axis component slidingly coupled via at least one bearing assembly to and translating with the at least one y-axis component along the y-axis. The at least one x-axis component is configured to reciprocate substantially perpendicularly to the y-axis relative to the at least one y-axis component, and includes an orbital output component and an orbital linking component disposed substantially concentric with the orbital output component. The system also includes a stationary output component rotatably attached to the base in a direction that is substantially perpendicular to both the x-axis and y-axis, and a stationary linking component rotatably attached to the base in a direction that is substantially concentric with the stationary output component.

A cylinder unit includes a piston disposed in the cylinder bore that is connected to a piston connecting frame member. The piston connecting frame member replaces a conventional connecting rod, and reciprocates exclusively along the bore axis. A crank connecting member has a linear rail at its top that is captured in a transverse gap along the bottom of the piston connecting frame member, and converts the circular movement of a crank throw to linear motion of the piston connecting frame member.

An internal combustion engine is provided, which includes an engine body provided with a cylinder and a piston reciprocatably accommodated in the cylinder, a crankshaft that converts reciprocating movement of the piston into rotational movement, and a bearing member pivotally supporting the crankshaft via lubricating oil. The crankshaft includes a crank journal pivotally supported by the bearing member, and a counterweight extending radially outward from an axial end part of the crank journal. The crank journal has a recess formed in a part thereof corresponding to the extended position of the counterweight, the recess being depressed radially inwardly. The recess is deeper at the axial end part of the crank journal than an axial center part.

An internal combustion engine is provided, which includes an engine body provided with a cylinder and a piston reciprocatably accommodated in the cylinder, a crankshaft that converts reciprocating movement of the piston into rotational movement, and a bearing member pivotally supporting the crankshaft via lubricating oil. The crankshaft includes a crank journal pivotally supported by the bearing member, and a counterweight extending radially outward from an axial end part of the crank journal. The crank journal has a recess formed in a part thereof corresponding to the extended position of the counterweight, the recess being depressed radially inwardly. The recess is deeper at the axial end part of the crank journal than an axial center part.

A crankshaft assembly, a compressor and a refrigeration device are provided. The crankshaft assembly has an eccentric shaft component, a spindle component and a main screw oil pump. The eccentric shaft component has an eccentric cavity, and the spindle component has a first cavity communicated with the eccentric cavity. A first through-hole and a second through-hole in a first spindle are each communicated with the first cavity. An outer surface of the first spindle is provided with a first spiral oil groove connecting the first through-hole and the second through-hole. An outer surface of the main screw oil pump is provided with a second spiral oil groove along its length direction, and a spiral direction of the second spiral oil groove is opposite that of the first spiral oil groove.

Provided is a half bearing constituting a sliding bearing that is unlikely to cause damage during an operation of an internal combustion engine. The half bearing includes at least one protrusion, and the protrusion projects outward in a radial direction from an outer circumferential surface. A recessed portion that is recessed inward in the radial direction from the outer circumferential surface is formed over the entire inner-circumferential length between the protrusion and a circumferential-direction end surface of the half bearing. Two radial-direction grooves are formed in the circumferential-direction end surface of the half bearing relative to the protrusion, and each of the radial-direction grooves is adjacent to each of recessed portion side surfaces. The radial-direction grooves extend in the radial direction along the recessed portion side surfaces and are separated from the recessed portion at a midpoint of the extension. An inner circumferential surface-side end portion in an extending direction of the radial-direction grooves is located between a recessed portion bottom surface and an inner circumferential surface of the half bearing. A groove width and a groove depth of the radial-direction grooves decrease from the position separated from the recessed portion toward the inner circumferential surface-side end portion and reach zero at the inner circumferential surface-side end portion.

A crankshaft bearing structure is provided capable of properly lubricating a thrust bearing even when low-viscosity oil is used in an engine. The crankshaft bearing structure includes a crankshaft, a cylinder block, plural journal bearings, and thrust bearings. Each of the plural journal bearings is annularly attached to a respective one of plural crank journals when the crankshaft is rotating. The thrust bearings are attached to a shaft support section, which supports the crank journal, in the cylinder block, to restrict movement of the crankshaft in a direction along an axis. The upper journal bearing annularly attached to the crank journal has a circumferential groove provided in an inner circumferential surface, connected to an oil hole, and extending in a circumferential direction.