Abstract:
An orifice for a hydrostatic system includes a plurality of means for providing flow communication from a first side of the orifice to a second side of the orifice such that the flow communication is maintained when less than all of the means are blocked.

Description:
BACKGROUND OF INVENTION  
         [0001]    This invention relates generally to hydrostatic lubrication systems and, more particularly, to orifices for hydrostatic lubrication systems.  
           [0002]    In a hydrostatic lubrication system, a lubricant, typically oil, is supplied under an external pressure sufficient to separate opposing surfaces of a machine. The lubricant forms a fluid film between the opposing surfaces and reduces friction and, accordingly, reduces wear of the opposing surfaces. The external pressure is provided by a pump and is typically metered though the use of an orifice. The orifice restricts flow therethrough and reduces a pressure provided by the pump to a lower pressure for use in the hydrostatic lubrication system.  
           [0003]    The orifice is typically a precision hole that meters a lubrication fluid for a hydrostatic system. Typically, the lubrication fluid flows through a filter to remove particles that can block or plug the orifice. However, the filter is positioned away from the orifice and the lubrication fluid sometimes picks up debris originating between the filter and the orifice. The debris can cause a blockage of the orifice, which causes a failure of the hydrostatic system. A failure of the hydrostatic system leads to increased wear and, sometimes, a complete breakdown of the machine requiring an expenditure of repair costs.  
         SUMMARY OF INVENTION  
         [0004]    In one aspect, an orifice for a hydrostatic system includes a plurality of means for providing flow communication from a first side of the orifice to a second side of the orifice such that the flow communication is maintained when less than all of the means are blocked.  
           [0005]    In another aspect, a method for fabricating an orifice for a hydrostatic device is provided. The method includes providing a body, disposing at least one outlet opening on the body, and disposing a plurality of inlet surface openings on the body in flow communication with the outlet. Each inlet surface opening is smaller than the outlet opening.  
           [0006]    In a further aspect, an orifice for a hydrostatic system includes a body, at least one outlet opening disposed on the body, and a plurality of inlet surface openings disposed on the body in flow communication with the outlet. Each inlet surface opening is smaller than the outlet opening. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]    [0007]FIG. 1 is a side view of a multi-inlet orifice.  
         [0008]    [0008]FIG. 2 is a plan view of a lubrication system including the multi-inlet orifice shown in FIG. 1.  
         [0009]    [0009]FIG. 3 is side view of a precision multi-inlet orifice.  
         [0010]    [0010]FIG. 4 is a side view of a central thread multi-inlet orifice. 
     
    
     DETAILED DESCRIPTION  
       [0011]    [0011]FIG. 1 is a side view of a multi-inlet orifice  10  including a first end  12 , a second end  14 , and an outer surface  16  extending from first end  12  to second end  14 . Multi-inlet orifice  10  also includes a plurality of inlet surface openings  18 , at least one inlet end opening  20 , an outlet opening  22 , and an axis  24 . In an alternative embodiment, multi-inlet orifice does not include any inlet end openings  20 . In one embodiment, outer surface  16  includes a threaded portion  26  proximate second end  14 . An outlet channel  28  extends from an interior end  30  to outlet opening  22 . A plurality of inlet channels  32  extend from outlet channel  28  to inlet surface openings  18  such that inlet surface openings  18  are in flow communication with outlet opening  22 . In one embodiment, inlet channels  32  extend linearly and substantially radially to inlet surface openings  18 . In an alternative embodiment, inlet channels  32  extend obliquely to surface openings  18 . In another embodiment, inlet channels  32  include one or more curved portions (not shown). In an exemplary embodiment, multi-inlet orifice  10  includes eight or more inlet surface openings  18 .  
         [0012]    At least one axial inlet channel  34  extends from interior end  30  to inlet end opening(s)  20  such that inlet end opening(s)  20  are in flow communication with outlet opening  22 . In one embodiment, axial inlet channel  34  extends linearly and substantially axially from interior end  30  to inlet end opening(s)  20 . In an alternative embodiment, axial channel  34  extends obliquely from interior end  30  to inlet opening(s)  20 . In another embodiment, axial channel  34  includes one or more curved portions (not shown). Inlet surface openings  18  and inlet end opening(s)  20  are substantially circular and include a radius (not shown) less than a radius (not shown) of outlet opening  22 , which is also substantially circular. In an exemplary embodiment, inlet surface openings  18  and inlet end opening(s)  20  have substantially similar diameters. In an alternative embodiment, inlet surface openings  18  and inlet end opening(s)  20  and outlet opening  22  are square and inlet surface openings  18  and inlet end opening(s)  20  are smaller than outlet opening  22 . In an exemplary embodiment, multi-inlet orifice  10  is fabricated from a metal, including, but not limited to, aluminum, brass, copper, and steel. In an alternative exemplary embodiment, multi-inlet orifice  10  is fabricated from a non-metal, including, but not limited to, plastics, ceramics, crystals, and composites.  
         [0013]    During operation, a lubricating fluid (not shown) flows in inlet surface openings  18  and inlet end opening(s)  20 , and flows out outlet opening  22 . Since inlet surface openings  18  and inlet end opening(s)  20  are smaller than outlet opening  22 , debris that enters any particular inlet surface opening  18  and/or inlet end opening(s)  20  is sufficiently small to pass through outlet opening  22 . Accordingly, the debris does not block outlet opening  22 . It is contemplated that the benefits of a multi-inlet orifice  10  accrue to orifices with inlet openings (surface and/or end) and outlet openings of varying shape, including, but not limited to, shapes with at least one line of symmetry and shapes with no line of symmetry. Furthermore, because there are a plurality of inlet surface openings  18  in combination with inlet end opening(s)  20 , a blockage of less than all of inlet surface opening  18  and inlet end opening(s)  20  does not prevent lubrication fluid from entering a different inlet surface opening  18  and/or inlet end opening(s)  20 , and exiting through outlet opening  22 . In other words, a blockage of less than all of openings  18  and  20  does not cause a blockage of outlet opening  22 .  
         [0014]    [0014]FIG. 2 is a plan view of a lubrication system  40  including multi-inlet orifice  10  shown in FIG. 1. Lubrication system  40  includes multi-inlet orifice  10 , a lubrication channel  42 , a hydrostatic system  44 , a sump  46 , a filter  48 , and a pump  50 . Multi-inlet orifice  10  is positioned within lubrication channel  42  such that inlet surface openings  18  and inlet end opening(s)  20  receive a lubrication fluid (not shown) from pump  50 . Outlet opening  22  is in flow communication with hydrostatic system  44 . Filter  48  is positioned between sump  46  and pump  50 .  
         [0015]    During operation of lubrication system  40 , lubrication fluid is in sump  46 . Pump  50  draws the fluid from sump  46  through filter  48  and delivers the fluid to lubrication channel  42  thereby pressurizing lubrication channel  42 . Since the lubrication fluid in channel  42  is pressurized, the fluid flows in inlet surface openings  18  and inlet end opening(s)  20 , and the fluid flows out outlet opening  22  to hydrostatic system  44  where the fluid lubricates at least one moving part (not shown). The fluid then returns to sump  46  to be re-circulated. Although filter  48  removes debris from the fluid, the fluid can pick up debris originating between filter  48  and multi-inlet orifice  10 . Since multi-inlet orifice  10  includes a plurality of inlet surface openings  18  in combination with inlet end opening(s)  20 , a blockage of less than all of inlet surface opening  18  and inlet end opening(s)  20  does not cause a blockage of outlet opening  22 . Accordingly, hydrostatic system  44  receives fluid not withstanding a blockage of less than all of inlet surface openings  18  and inlet end opening(s)  20 . It is contemplated that the benefits of a multi-inlet orifice accrue to hydraulic systems and, therefore, as used herein the term “hydrostatic” includes “hydraulic”.  
         [0016]    [0016]FIG. 3 is a side view of a precision multi-inlet orifice  60  including a precision control unit  62  and a body  64 . Precision control unit  62  includes an axial bore  66  that extends from an interior end  68  to an outlet opening  70 . In one embodiment, precision control unit  62  is fabricated from a crystal. In another embodiment, precision control unit  62  is fabricated from a material other than crystal. Body  64  includes a first axial bore  72  extending from a first end  74  of body  64  toward a second end  76  of body  64 . Body  64  also includes a plurality of inlet channels  78  that extend from first axial bore  72  to a plurality of inlet surface openings  80 . Bore  72  includes a diameter (not shown) at least as large as a diameter (not shown) as bore  66 . Inlet channels  78  are have cross-sections sized smaller than a cross-section (not shown) of bore  66  such that any particle sufficiently small enough to pass through inlet channels  78  can pass through bore  66 . In an exemplary embodiment, inlet channels  78  extend radially to inlet surface openings  80 . In an alternative embodiment, inlet channels  78  extend obliquely from first axial bore  72  to inlet surface openings  80 . In one embodiment, inlet channels  78  include one or more arcuate sections (not shown). In an exemplary embodiment, there are eight inlet channels  78  positioned in two rows of four and, within each row, inlet channels  78  are spaced  90  apart circumferentially.  
         [0017]    Body  64  also includes a shoulder  82  selectively sized to receive precision control unit  62 . In one embodiment, precision multi-inlet orifice  60  is attached to a hydrostatic system such as system  44  (shown in FIG. 2) in conventional manner such as keying, press fitted (friction fitted), peening, doweling and/or adhesively attached. In another embodiment, body  64  includes a threaded portion (not shown) substantially identical to threaded portion  26  of multi-inlet orifice  10  (shown in FIG. 1) and precision multi-inlet orifice is threadibly attached to the hydrostatic system. Body  64  also includes at least one inlet end opening  84  in flow communication with first axial bore  72  via at least one axial channel  86 . In an alternative embodiment, body  64  does not include any inlet end openings  84  During operation, fluid flows in inlet surface openings  80  and inlet end opening (s)  84 , through inlet channels  78  and axial channel  86 , and then through bore  72  to bore  66 . The fluid flows through bore  66  out outlet opening  70 . Since inlet surface openings  80  and inlet end opening(s)  90  are smaller than outlet opening  70 , debris that enters any particular inlet surface opening  80  and/or inlet end opening(s)  90  is sufficiently small to pass through outlet opening  70 . Additionally, since precision multi-inlet orifice  60  includes a plurality of inlet surface openings  84  and inlet end opening(s)  90 , a blockage of less than all particular inlet surface opening  80  and/or inlet end opening(s)  90  does not cause a blockage of outlet opening  70 .  
         [0018]    [0018]FIG. 4 is a side view of a central thread multi-inlet orifice  110  including a first end  112  and a second end  114 . Central thread multi-inlet orifice  110  also includes a central thread portion  116  disposed between first end  112  and second end  114 . Central thread multi-inlet orifice  110  also includes a plurality of inlet surface openings  118  extending outward and at least one end outlet  120  extending substantially axially. Central thread multi-inlet  110  also includes an outlet opening  122  extending substantially axially.  
         [0019]    During operation of central thread multi-inlet orifice  46  in a lubrication system  40  as shown in FIG. 2, central thread multi-inlet orifice operates  46  as described above with reference to multi-inlet orifice  10 .  
         [0020]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.