Abstract:
A hydraulic flange connection formed on a tube having a first groove formed in the outside of the flange at a first stress area and a second groove formed in the outside surface of the flange at a secondary stress area and extending in a direction substantially perpendicular to a central cavity formed in the tube.

Description:
FIELD OF THE INVENTION 
       [0001]    The present hydraulic flange connection relates to a mechanical flanged connection primarily used in connection of a high pressure hydraulic line to a prime operator such as a hydraulic motor, pump or valve assembly. A circumferential secondary groove is located in an outside surface of the flange positioned to reduce the operational stresses of the flange connector thereby increasing its operational life. 
       BACKGROUND OF THE INVENTION 
       [0002]    Mechanical connections are used to connect high pressure hydraulic sources to prime movers such as a pump, motor or a valve assembly. One type of connector used in these applications is what is known as a flange. The Society of Automotive Engineers, through Standard J518, and the International Organization for Standardization, through standard 6162, have standardized on a flanged connector under the industry names of Code 61 or Code 62. The high hydraulic pressures handled by this type of connector necessarily includes pressure waves that increase the stress levels within the flanged connector that reduce the operational life of the connector. Also, mechanically induced bending loads which can result in cyclic fatigue and eventual failure. The prior art discloses a groove located in the surface of the connector at the area where the vertical and horizontal surfaces of the flange section and a transition section meet. This groove operates to lower the stress concentrations at this particular location on the connector where the vertical and horizontal surfaces meet to form the flange area. This method of reducing bending stresses is known in the art and has been used in hydraulic connectors and in other mechanical devices. The reduction of the sharp surface transition from the vertical to the horizontal by the introduction of the groove reduces the maximum bending stresses in the flange connector. 
         [0003]    A method to reduce the bending induced stress in the flange connector will either reduce the thickness of the material required to make the connector and/or reduce certain dimensions of the flange section of the part to reduce the overall size is a desired improvement to the prior art. 
       SUMMARY OF THE INVENTION 
       [0004]    In order to improve the performance and reduce the material thickness and allow for alternative materials to be utilized in the manufacture and use of a flange connector, an improved flange connector is disclosed herein. This improved mechanical flange connector can be used to provide a fluid flow path and connect pressurized hydraulic system components, especially those experiencing high operating pressures. 
         [0005]    Specifically, in terms of the structure of this improved flange connector, a circumferential second groove is formed in the flange approximately adjacent to a prior art first groove where in a first embodiment, the second groove is oriented approximately perpendicular to the longitudinal axis of the tube that is joined to and extends from the flange connector. The second groove significantly reduces the bending stresses in the section of the flange connector know as the flange section and specifically at the areas where there is a change in cross-sectional area. The circumferential first groove acts to reduce the stresses at that point where the cross-sectional area changes from that of the flange section to the transition section. However, the stresses can be further reduced with the introduction of this second groove in the transition section. The first groove is substantially circular in profile at its root while in the first embodiment, the second groove is shown as a “V” shaped groove. 
         [0006]    In a first alternative embodiment, the circumferential second groove is enlarged and given a relatively large radius to further lower the stress level over that of the prior art designs. A typical radius for the first alternative second groove is approximately one third the radius of the tube section. 
         [0007]    In a second alternative embodiment, the circumferential second groove is enlarged still further and the second groove is given a relatively larger radius to further lower the stress levels as compared to the prior art. The radius of the second groove for this second alternative embodiment is approximately one half the radius of the tube section. 
         [0008]    Other shapes of either/or the first and second groove can be varied as necessary to facilitate manufacturing and to minimize the stresses in the flange connector to improve performance and packaging. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a cross-sectional view of a prior art flange connector; 
           [0010]      FIG. 2  is a cross-sectional view of the flange connector having a second stress groove; 
           [0011]      FIG. 3  is a sectional view of a portion of the flange connector of  FIG. 2 ; 
           [0012]      FIG. 4  is a perspective view of the flange connector of  FIG. 2 . 
           [0013]      FIG. 5  is a cross-sectional view of a second embodiment of the flange connector; 
           [0014]      FIG. 6  is a cross-sectional view of a third embodiment of the flange connector; and 
           [0015]      FIG. 7  is a cross-sectional view of a fourth embodiment of the flange connector. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
         [0017]    Moreover, a number of constants may be introduced in the discussion that follows. In some cases illustrative values of the constants are provided. In other cases, no specific values are given. The values of the constants will depend on characteristics of the associated hardware and the interrelationship of such characteristics with one another as well as environmental conditions and the operational conditions associated with the disclosed system. 
         [0018]    Now referring to  FIG. 1  of the drawings, a cross-sectional view of a prior art flange connector  20  is shown. A tube section  21  is cast or otherwise formed with or attached to a flange section  22  though a transition section  28 . The flange section  22  is mechanically attached to a hydraulic component such as a pump or motor or valve assembly to provide for a fluid connection and conduit path between such components. A seal groove  24  is shaped to accommodate a seal such as an O-ring. The O-ring (not shown) is trapped between the seal groove  24  and the hydraulic component (not shown) and is slightly compressed so as to provide a fluid seal there between. A central cavity  26  provides for the transport of a pressurized fluid such as hydraulic oil from a pressure source to the hydraulic (or fluid) component such as a pump, motor, etc. A transition section  28  is disposed between the tube section  21  and the flange section  22 . When the flange connector  20  is subjected to pressure induced vibrations or otherwise structurally loaded by an attached hose or by the hydraulic component, bending stresses or other induced stresses can occur which can result in leakage of the transported fluid such as hydraulic fluid. In the prior art, the induced stresses are lowered with the incorporation of a circumferential first groove  30  located at the intersection of the flange section  22  and the transition section  28 . In the drawings, a first groove  30  is shown having a radiused shape but many other types of shapes could be utilized to reduce the induced stresses at that location and otherwise in the flange connector  20 . 
         [0019]    Now referring to  FIG. 2 , a cross-sectional view of an exemplary flange connector  40  having reduced levels of operationally induced stresses is shown. A tube section  41  is cast or otherwise formed with or attached to a flange section  42  through the transition section  48 . The flange section  42  is mechanically attached to a hydraulic component such as a pump or motor or valve assembly. A circumferential seal groove  44  is shaped to accommodate a seal such as an O-ring. The O-ring (not shown) is trapped between the seal groove  44  and the hydraulic component (not shown) and is slightly compressed so as to provide a fluid seal there between. A central cavity  46  provides for the transport of a pressurized fluid such as hydraulic oil from a pressure source to the hydraulic (or fluid) component such as a pump, motor, etc. A transition section  48  is disposed between the tube section  41  and the flange section  42 . When the flange connector  40  is subjected to pressure induced vibrations or otherwise structurally loaded by an attached hose or by the hydraulic component, bending stresses or other operational stresses can occur which can result in component failure and leakage of the transported fluid such as hydraulic fluid. The operationally induced bending stresses are lowered with the incorporation of a circumferential first groove  50  located at the intersection of the flange section  42  and the transition section  48 . In the drawings, a first groove  50  is shown having a radiused shape but many other types of shapes could be utilized to reduce the induced stresses at that location and otherwise in the flange connector  40 . 
         [0020]    To further reduce the induced bending stresses in the flange connector  40 , a circumferential second groove  54  is formed or machined in the transition section  48 . The second groove  54  works in conjunction with the first groove  50  to minimize the induced stresses but the second groove  54  could be utilized by itself without a first groove  50  to reduce induced stress levels thereby improving performance of the flange connector  40 . 
         [0021]    The shape of the second groove  54  is shown as having a “V” shape where the “V” has a radiused bottom section  56  to minimize stresses. This is more clearly shown in  FIG. 3  of the drawings. Even though the shape of the second groove  54  is shown as having a “V” shape, many other shapes for the second groove  54  could be utilized to lower the level of stresses within the flange connector  50 . Two alternate embodiments that use other shapes for the second groove  54  are shown with reference to  FIGS. 4 and 5 . For example, a “U” shape could be utilized if that would be more easily manufactured or if it was shown to reduce the level of the induced bending stresses in the flange connector  40 . 
         [0022]    Now referring to  FIG. 3  of the drawings, a portion of the flange connector  50  of  FIG. 2  is shown where both the first and second grooves  50 ,  54  are enlarged for clarity of illustration. More clearly shown is the radiused bottom section  56  of the second groove  54  that further lowers the induced stress level. Also more clearly shown is the radiused shape of the first groove  50 . The first and second grooves  50 ,  54  are located between the flange section  42  and the transition section  48 . 
         [0023]    Now referring to  FIG. 4  of the drawings, a perspective view of the flange connector  40  is shown and this figure clearly shows how the first and second grooves  50 ,  54  are circumferential in shape. The first groove  50  is located at the root of the mounting flange  42  and is located between the mounting flange  42  and the second groove  54 . The second groove  54  is located between the first groove  50  and the transition section  48  which is joined to the tube section  41 . The contour of the first groove  50  is radiused to lower stress levels in that particular area of the flange connector  40 . To further reduce stress levels in the flange connector  40 , a second groove  54  is formed in the area between the first groove  50  and the tube  41 . The stress level under specific conditions is lowered from 511 Mpa for the prior art configuration shown in  FIG. 1  down to 467 Mpa for this configuration shown in  FIGS. 2-4 . 
         [0024]    Now referring to  FIG. 5  of the drawings, a cross-section of a first alternate embodiment of the flanged connector  60  is shown. The shape and the orientation of the second groove  74  has been modified to lower the maximum stress in the area of the second groove  74  down to 408 Mpa under the specified conditions. Flange connector  60  has reduced levels of induced bending stresses which can result in structural and operational benefits such as the use of thinner walled sections and/or improved life expectancy or higher operating pressures. A tube section  61  is cast or otherwise formed with or attached to a flange section  62 . The flange section  62  is attached to a hydraulic component such as a pump or motor or valve assembly. A circumferential seal groove  64  is shaped to accommodate a seal such as an O-ring. The O-ring (not shown) is trapped between the seal groove  64  and the hydraulic component (not shown) and is slightly compressed so as to provide a fluid seal there between. A central cavity  66  provides for the transport of a pressurized fluid such as hydraulic oil from a pressure source to the hydraulic (or fluid) component such as a pump, motor, etc. A transition section  68  is disposed between the tube section  61  and the flange section  62 . When the flange connector  60  is subjected to pressure induced vibrations or otherwise structurally loaded by an attached hose or by the hydraulic component, bending stresses or other induced stresses can occur which can result in leakage of the transported fluid such as hydraulic fluid. These induced stresses are lowered with the incorporation of a circumferential first groove  70  located at the intersection of the flange section  62  and the transition section  68 . In  FIG. 5 , a first groove  70  is shown having a radiused shape but many other types of shapes could be utilized to reduce the induced stresses at that location and otherwise in the flange connector  60 . 
         [0025]    To further reduce the bending and other induced stresses in the flange connector  60  a circumferential second groove  74  is formed or machined adjacent to the transition section  68 . The second groove  74  works in conjunction with the first groove  70  to minimize the induced stress levels but the second groove  74  could be utilized by itself without a first groove  70  to reduce induced stress levels thereby improving performance of the flange connector  60 . The shape of the second groove  74  is shown as having a “dished out” shape where the second groove  74  lowers the stress level down to 408 Mpa when used in conjunction with the first groove  70  although it could be used individually to lower the stress levels in the flange connector  60 . The second groove  74  has a radius of approximately one third of the radius of the tube section  61 . 
         [0026]    Now referring to  FIG. 6 , a cross-sectional view of a second alternative embodiment of the exemplary flange connector  80  having reduced levels of induced stress is shown. A tube section  81  is cast or otherwise formed with or attached to a flange section  82 . The flange section  82  is attached to a hydraulic component such as a pump or motor or valve assembly. A circumferential seal groove  84  is shaped to accommodate a seal such as an O-ring. The O-ring (not shown) is trapped between the seal groove  84  and the hydraulic component (not shown) and is slightly compressed so as to provide a fluid seal there between. A central cavity  86  provides for the transport of a pressurized fluid such as hydraulic oil from a pressure source to the hydraulic (or fluid) component such as a pump, motor, control valve, header, etc. A transition section  88  is disposed between the tube section  81  and the flange section  82 . When the flange connector  80  is subjected to pressure induced vibrations or otherwise structurally loaded by an attached hose or by the hydraulic component, bending stresses or other induced stresses can occur which can result in leakage of the transported fluid such as hydraulic fluid. The induced stresses are lowered with the incorporation of a circumferential first groove  90  located at the intersection of the flange section  82  and the transition section  88 . In the drawings, the first groove  90  is shown having a radiused shape but many other types of shapes could be utilized to reduce the induced stresses at that location and otherwise in the flange connector  80 . 
         [0027]    To further reduce the operationally induced mechanical stresses in the flange connector  80 , a circumferential second groove  94  is formed or machined in the transition section  88  between the first groove  90  and the tube section  81 . The second groove  94  works in conjunction with the first groove  90  to minimize the induced stresses but the second groove  94  could be utilized by itself without a first groove  90  to reduce induced stress levels thereby improving performance of the flange connector  80 . 
         [0028]    The shape of the second groove  94  is shown as having a bowl shape with a relatively large radius especially when compared to the shape of the second groove  34  shown in  FIG. 2 . In fact, the radius of the second groove  94  in  FIG. 6  is noticeably larger than that of the second groove  74  shown in the first alternative embodiment as shown in  FIG. 5 . The radius of the second groove  94  is approximately one half of the radius of the tube section  81 . The stress level under the same specified conditions is lower than the stresses predicted in the flanged connector of  FIG. 5 . 
         [0029]    As shown in  FIG. 7 , the second groove  94  can be replaced by a plurality of secondary circumferential grooves  104  that are similar in shape to the second groove  94  or they can be narrower width grooves. The secondary circumferential grooves  104  can be of the general size and of a general shape of the first groove  90  or the second groove  54 . The exact number and shape are dependent on the geometry of the flange  42  and tube  41  and the application parameters under which the flange  40  is being used. The secondary grooves  104  can be of the same shape or they can vary in shape and depth. 
         [0030]    The present disclosure has been particularly shown and described with reference to the foregoing illustrations, which are merely illustrative of the best modes for carrying out the disclosure. It should be understood by those skilled in the art that various alternatives to the illustrations of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing illustrations are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.