A turbocharger and a method of manufacturing a floating bush with which noise can be reduced, and the rotation speed can be increased. In a turbocharger in which a rotating shaft having a circular cross-section and connecting a turbine rotor and a compressor rotor is supported in a freely rotatable manner, at two axially separated positions via floating bushes, by an inner circumferential surface disposed so as to surround the rotating shaft in a bearing housing, an inner circumferential surface of each of the floating bushes has a non-circular shape in which the curvature of the cross-sectional shape varies in the circumferential direction.

The invention relates to an exhaust-gas-driven turbocharger having a hydrodynamic plain bearing having a rotor and a stator, the rotor being rotatable with respect to the stator, the rotor bearing surface being located opposite a counter-surface of the stator in order to generate hydrodynamic pressure in the region of a converging gap. In such a hydrodynamic plain bearing, the application properties can be improved by the fact that the rotor bearing surface and/or the counter-surface constitutes in a section view, in the context of a section along and through the rotation axis, a continuous bearing contour that is constituted from convex or concave curvatures and/or from at least two contour segments that are embodied as straight lines and/or curvatures. The invention also relates to a hydrodynamic plain bearing or bearing arrangement having such a plain bearing.

The invention relates to an exhaust-gas-driven turbocharger having a hydrodynamic plain bearing having a rotor and a stator, the rotor being rotatable with respect to the stator, the rotor bearing surface being located opposite a counter-surface of the stator in order to generate hydrodynamic pressure in the region of a converging gap. In such a hydrodynamic plain bearing, the application properties can be improved by the fact that the rotor bearing surface and/or the counter-surface constitutes in a section view, in the context of a section along and through the rotation axis, a continuous bearing contour that is constituted from convex or concave curvatures and/or from at least two contour segments that are embodied as straight lines and/or curvatures. The invention also relates to a hydrodynamic plain bearing or bearing arrangement having such a plain bearing.

A rotation induction device for a vehicle includes an upper case member, a lower case member, a center plate, and a friction reduction part. The upper case member has a piston rod disposed therethrough. The lower case member, disposed under the upper case member, has the piston rod disposed therethrough. The center plate, disposed between the upper and lower case members such that the piston rod passes through the center plate, is configured to induce either one or both of the upper and lower case members to rotate. The friction reduction part, configured to reduce friction, is selectively disposed at a contact surface between the upper case member and the center plate, and a contact surface between the center plate and the lower case member. Each of the upper case member, the lower case member, and the center plate is composed of a synthetic resin material.

A rotation induction device for a vehicle includes an upper case member, a lower case member, a center plate, and a lubricant storage part. The upper case member has a piston rod disposed therethrough. The lower case member, disposed under the upper case member, has the piston rod disposed therethrough. The center plate, disposed between the upper and lower case members such that the piston rod passes through the center plate, is configured to induce either one or both of the upper and lower case members to rotate. The lubricant storage part is formed in the center plate and configured to store lubricant therein. Each of the upper case member, the lower case member, and the center plate is composed of a synthetic resin material.

A turbocharger (1A) includes a rotary shaft (2), a journal hearing (5A), and a bearing housing (10). The journal hearing (5A) includes load support surfaces (14 and 15), a first gap forming portion (F1), and a second gap forming portion (F2). The first gap forming portion (F1) firms a first gap (101) in a radial direction between the load support surfaces (14 and 15) adjacent to each other in a direction of a central axis (O). The second gap forming portion (F2) forms a second gap (102) smaller than the first gap in the radial direction between the load support surfaces (14 and 15) adjacent to each other in the direction of the central axis (O).

A bearing condition monitoring device is a bearing condition monitoring device for monitoring a condition of a thrust bearing for holding a rotational shaft in a thrust direction. The bearing condition monitoring device includes a first temperature sensor for measuring a temperature of the thrust bearing, and an arithmetic device for counting a frequency at which an evaluation index of a thrust load on the basis of a measurement value by the first temperature sensor exceeds an allowable value, and for outputting an abnormality in the condition of the thrust bearing if the counted frequency exceeds a threshold. The arithmetic device may count, as the frequency, only a case where a state in which the thrust load exceeds an upper limit load continues for not less than a predetermined time.

A plain bearing includes: a bearing body; a radial bearing portion arranged on an inner peripheral surface of the bearing body; a thrust bearing portion arranged on an axial end surface of the bearing body; a damper portion arranged on an outer peripheral surface of the bearing body; a dam portion arranged on the outer peripheral surface of the bearing body; and an oil hole having an inlet that opens to at least one of the outer peripheral surface of the bearing body and the dam portion, and an outlet that opens to the inner peripheral surface of the bearing body. The inlet, at least a part of the dam portion, and the damper portion are arranged in this order from an axially inner side toward an axially outer side. An outlet of an upstream side oil passage is connected to the inlet on a radially outer side.

A floating bush bearing configured to support a rotational shaft rotatably includes: a floating bush body part formed to have a cylindrical shape having an insertion hole through which the rotational shaft is inserted. The floating bush body part includes: an inner peripheral surface; an outer peripheral surface having a greater width dimension than the inner peripheral surface in an axial direction of the floating bush body part; and an axial end surface which connects an end of the inner peripheral surface and an end of the outer peripheral surface, the axial end surface including a vertical surface extending along a direction orthogonal to the axial direction from the end of the outer peripheral surface toward a radially inner side and an oblique surface extending from a radially inner end of the vertical surface toward the end of the inner peripheral surface. The oblique surface has a protruding portion protruding from a virtual line which linearly connects the radially inner end of the vertical surface and the end of the inner peripheral surface.

A semi-floating bearing (multi-lobe bearing) includes a radial bearing surface that is formed on an inner circumferential surface of a body, and that includes a plurality of arcuate surfaces having mutually different centers of curvature and arranged adjacent to each other in a circumferential direction of the body; and axial grooves formed on the radial bearing surface and extending in an axial direction of the shaft, a center position of the axial groove in the circumferential direction being located at a position spaced apart rearwardly from a boundary portion between the plurality of arcuate surfaces in the circumferential direction of the shaft within an area from the boundary portion to a central position of the arcuate surfaces in the circumferential direction.