Patent Application
20180058499
The present disclosure relates to thrust washers and more particularly, to thrust washers with hydrodynamic features.
This section provides background information related to the present disclosure which is not necessarily prior art.
Thrust washers fail due to loss of lubrication and high interface temperature conditions. This present disclosure uses improved groove features to improve the ability to form thin lubricant films. The features allow better film generation and thereby lower friction and interface temperature. These features allow for use of very low lubrication conditions as they more effectively use the lubricant than conventional groove geometries. The result of these new designs allows them to be used in more aggressive speed and pressure applications while also reducing the torque compared to designs used today.
The present disclosure is directed to a thrust bearing made from a thermoplastic or thermoset material manufactured using machining or plastic molding techniques. The washer has grooves or partial grooves with the geometric features designed to promote a fluid flow under washer and generate/retain fluid film to support thrust forces and rotational speeds. This results in the washer running at lower friction as it rides on the fluid film generated by the design features.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
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It should be noted that the groove inlet 34 defines a lead in radius that promotes the formation of a fluid film under the thrust washer 10 along the lands 26 as an opposing surface bears against the thrust washer 10 and relative rotation occurs between the opposing surface and thrust washer 10. Each of the plurality of grooves 24 also include a back groove portion 38 that can include various alternative geometries that are not intended to be the subject of this disclosure. By way of example only, the geometry of the back groove portion 38 can include a symmetrical elliptical geometry as illustrated in
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The thrust washer 10, 110, 210, 310 can be made from engineering plastic materials including thermoplastics, thermosets, or combinations of both or metals, ceramics or other known thrust washer materials. The thrust washer can include the recessed grooves as disclosed on only one axial face 16 or on both axial faces 16, 18. When the grooves 24 are provided on both faces, the grooves on each face can be offset to each other. When the grooves 24 are provided on both faces, the grooves on each face can be aligned with each other. In addition, it should be understood that a partial groove can be used that is closed on either the inside diameter or the outside diameter so that the grooves do not extend across the entire axial face 16, 18. In addition, the recessed grooves 24 can have a portion that breaks through an entire thickness of the thrust washer for communicating lubricant there through. In addition, the thrust washer can be provided with a combination of the different types of recessed grooves disclosed herein.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
