JOURNAL BEARING WITH INDENTED JOURNAL SURFACE

Abstract

A journal bearing for a crankshaft having indentations on the journal surface is disclosed. The indentations are designed to increase lubricant volume and decrease friction between the journal surface and the bearing surface. The indentations may be designed to intensify the hydrodynamic pressure when the crankshaft is rotating.

Claims

1. A journal bearing comprising: (a) a bearing surface; and (b) a journal surface; (c) wherein the journal surface includes one or more indentations.

2. The journal bearing of claim 1 wherein the indentations are pits.

3. The journal bearing of claim 1 wherein the indentations are elongated grooves.

4. The journal bearing of claim 1 wherein the indentations are elongated and disposed on the journal surface diagonally to the longitudinal axis of the journal.

5. The journal bearing of claim 1 wherein the indentations have a depth between 1/1000 of an inch and 50/1000 of an inch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects, and advantages of the present invention will be better understood with reference to the following description, appended claims, and accompanying drawings where:

[0008] FIG. 1 is an crankshaft-end view depicting a portion of a crankshaft, showing an exemplary rod journal disposed within a rod bearing.

[0009] FIG. 2 is a crankshaft-side view depicting a portion of a crankshaft, showing an exemplary rod journal disposed within a rod bearing.

[0010] FIG. 3 is a crankshaft-side view depicting a portion of a crankshaft, showing another exemplary rod journal disposed within a rod bearing.

DETAILED DESCRIPTION

[0011] In the summary above, and in the description below, reference is made to particular features of the invention in the context of exemplary embodiments of the invention. The features are described in the context of the exemplary embodiments to facilitate understanding. But the invention is not limited to the exemplary embodiments. And the features are not limited to the embodiments by which they are described. The invention provides a number of inventive features which can be combined in many ways, and the invention can be embodied in a wide variety of contexts. Unless expressly set forth as an essential feature of the invention, a feature of a particular embodiment should not be read into the claims.

[0012] Except as explicitly defined otherwise, the words and phrases used herein, including terms used in the claims, carry the same meaning they carry to one of ordinary skill in the art as ordinarily used in the art.

[0013] An exemplary indented journal is depicted in FIGS. 1 and 2. (FIG. 1 is an end view of a rod bearing/journal of a crankshaft connected to a piston via a connecting rod and FIG. 2 is a side view.) A piston 114 is connected to a crankshaft 110 through a connecting rod 102 at a rod bearing 100. In hydrodynamic operation (at operating rpm), a roughly uniform film of oil 103 separates the bearing surface 104 from the journal surface 108. The oil is provided through an oil passage 106 through the crankshaft and an oil hole 105 from the passage 106 to the gap between the surfaces 104, 108.

[0014] The journal surface 108 differs from the prior art in that it includes indentations 112 disposed on the surface 108 between the radiuses 116 of the journal. In one embodiment (e.g., a V8 engine), indentations 112 with a depth between roughly 1/1000 and 50/1000 of an inch are provided on the journal surface 108. The indentations 112 may be elongated, diagonally oriented (with respect to the crankshaft axis), and spaced evenly around the oil hole 105. In an alternative embodiment, the indentations take the form of pits. The indentations 112 may be provided on the journal surface 108 by, for example, cutting, machining, filing, stamping, or casting. In one embodiment, the indentations have a chamfer to provide a gradual leading lip and a gradual trailing edge (leading and trailing here are relative to the rotation of the crankshaft).

[0015] The indentations 112 are designed to collect and contain the oil (or other lubricant) to increase the oil volume and hydrodynamic state between the journal surface 108 and the bearing surface 104 in hydrodynamic operation. Further, the indentations 112 retain oil even when the crankshaft is idle, reducing oil starvation on start up. This will ease start-up stress when the crankshaft first starts turning, and thereby lower wear and tear on the journals/bearings.

[0016] The exemplary embodiment depicted in FIG. 3 differs from that depicted in FIGS. 1 and 2 in the orientation of the elongated indentations. The indentations 112* in FIG. 3 include a circumferentially wrapped (wormed) groove.

[0017] While the foregoing description focused on rod bearings, the invention is not limited to rod bearings. It may be implemented in a variety of journal bearing. For example, the invention may be implemented in either rod or main bearings (or both) of a crankshaft in an internal combustion engine.

[0018] While the foregoing description is directed to the preferred embodiments of the invention, other and further embodiments of the invention will be apparent to those skilled in the art and may be made without departing from the basic scope of the invention. And features described with reference to one embodiment may be combined with other embodiments, even if not explicitly stated above, without departing from the scope of the invention. The scope of the invention is defined by the claims which follow.