Patent Application
20080149423
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The present invention relates to a lubrication system, and more particularly to a system and method for lubricating power transmitting elements. In one aspect, the invention relates to a spline lubrication system.
Without proper lubrication to flush away or otherwise remove contaminants, power transmitting elements in engines progressively wear during use. Such wear results in decreased service life of a given piece of equipment. For example, a typical engine with a crankshaft employing internal splines may have a desired service life of 1500 hours. However, during engine use, the slight relative movement between the internal splines and the complementary external splines of an additional component engaged with the internal splines results in fretting and/or corrosion on the splines such that routine maintenance may be required after only 200 hours of use, or perhaps even less.
Accordingly, it would be desirable to provide a system and method for lubricating power-transmitting elements, such as splines, to reduce wear and to increase service life of such elements during use. Such a solution would, advantageously, reduce the amount of time and costs associated with maintaining equipment incorporating such power transmitting elements.
In one aspect, the present invention relates to a lubrication system for lubricating a power transmitting element in an engine. The system includes a main engine bearing, and a crankshaft in operational association with the main engine bearing. The crankshaft includes an end that has a cavity having a power transmitting element, and the cavity is capable of receiving and engaging an additional mechanism so as to transmit power thereto. The crankshaft further includes a first oil passage that is centrally disposed within the end and a second oil passage that extends from a main engine bearing into the crankshaft such that the first oil passage intersects the second oil passage. The system also includes a pump mechanism for circulating lubricating oil from the main engine bearing to the crankshaft through the second oil passage and the first oil passage, and then to the cavity so as to lubricate the power transmitting element. In one embodiment, the power transmitting element can include splines or a splined surface.
In another aspect, a method for lubricating one or more power transmitting elements in an engine is also disclosed.
Advantageously, during engine operation, a constant or substantially supply of lubricating oil can be provided to the power transmitting element so as to reduce component wear and, desirably, extend component service life.
Embodiments of the invention are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The invention is not limited in its application to the details of construction or the arrangement of the components illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in other various ways. Like reference numerals are used to indicate like components. In the drawings:
Lubricating oil 17, circulated to the rear bearing 15 by means of an existing engine oil pump or pumping mechanism 6, flows through the second oil passage 14 to the first oil passage 12 and then to the center of the cavity 19. A flow reducing orifice 18 is provided, typically in the first passage 12, to control the flow of lubricating oil 17 to the cavity 19. The lubricating oil 17 arriving at or near the center of the cavity 19 can then proceed outward to the inwardly-facing surface 13, and thus can eventually be used to lubricate both the surface 13 having the power-transmitting element (again not shown) and any additional component that is inserted into the cavity 19. In this fashion, a constant supply of lubricating oil is provided to the power transmitting element to flush away contaminant(s) contained therein or thereon during operation of the engine.
In at least some embodiments, in addition to the lubricating oil 17 being provided to the power transmitting element (e.g., an internal spline), as well as any interfacing element (e.g., a complementary external spline), it is possible that the lubricating oil 17 can also be further communicated to other devices by way of such additional components as are coupled to the crankshaft (e.g., PTO end) by way of the power transmitting elements. For example, if an additional component having an interfacing element (e.g., an external spline) also included a clutching mechanism (e.g., a multiple disc hydraulic actuated clutch), pressurized oil could be supplied from the center of the cavity 19 (as provided by the first oil passage 12 to a receiving passage within the external spline and subsequently to the clutching mechanism.
Turning to
As indicated by the arrows, lubricating oil is circulated to the rear bearing (not shown) by means of an existing engine oil lubrication pump (also not shown). The oil then flows through the second oil passage 34 to the first oil passage 32 and then to the cavity 26. Advantageously, a flow reducing orifice 36 is provided, typically in the first passage 32, to control the flow of lubricating oil to the cavity 26, and specifically the internal splines 30. To accomplish the flow-reduction, a plug 38 is included and driven or otherwise secured within the orifice. One plug that is suitable for use in the present invention to control oil flow to the internal splines is Cup Plug, part no. 24 139 05, available from Kohler, Co., located in Kohler, Wis. As further illustrated by the arrows, the lubricating oil arriving at the cavity 26 can then proceed to lubricate internal splines 30 of surface 28, as well as that any additional component(s) that is inserted into the cavity 26. Crankshafts often include a seal that prevents oil from dripping out of the engine. As shown in the present embodiment, such a seal is removed or eliminated, and instead, a passageway 40 is drilled or otherwise formed in a closure plate 42. Passageway 40 defines or provides a return oil path by which the lubricating oil is returned to the engine oil pump (not shown), for example via a crankcase sump (also not shown). In this way, a constant or substantially constant supply of lubricating oil is provided to the splines so as to remove contaminants during engine operation.
End use applications for the above invention include, but are not limited to, low cost utility engines (e.g., twin engines, single engines, etc.). Engines contemplated for use in the present invention include Command® Engines, also manufactured by Kohler, Co., located in Kohler, Wis.
It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.
