Patent Publication Number: US-2005142018-A1

Title: Increased capacity valving plates for a hydraulic motor

Description:
FIELD TO WHICH THE INVENTION RELATES  
      This invention relates to a series of plates for a hydraulic motor which improve the volumetric efficiency of the motor.  
     BACKGROUND OF THE INVENTION  
      Hydraulic motors have been utilized to provide power to a negative mechanism (such as a motor for a drivewheel or winch) or to derive power from a positive mechanism (such as a fluid pump driven by a gasoline motor). In some instances, the device is also utilized for a secondary purpose such as controlling the speed of rotation of itself or an auxiliary member.  
      Most hydraulic devices are relatively large in diameter for a given volumetric efficiency. The reason for this is the constraints in the cross-sections of the fluid passages which are necessary in the body of such hydraulic device. Examples of devices with limited cross-sectional passages include the Ross Gear MF-MG series which include a separate series of set diameter holes interconnected in alternate plates by set diagonal passages to provide for a fluid path axially through the manifold between (and separately from) the main bolts. In this Ross device both the holes and lateral slots have limited cross-sections, thus limiting the amount of fluid which is able to pass axially through the manifold. Some devices partially neighbor a bolt—examples include the bi-directional valving passage in U.S. Pat. No. 5,173,043, Reduced Size Hydraulic Motor, and the uni-directional passages in U.S. Pat. No. 3,452,680, Hydraulic Motor Pump Assembly and U.S. Pat. No. 3,452,543, Hydrostatic Device. However this usage is limited to a single location surround (U.S. Pat. No. 5,173,043) or a symmetrical Passageway (U.S. Pat. Nos. 3,452,680, 3,452,543).  
     SUMMARY OF THE INVENTION  
      It is an object of this invention to increase the volumetric efficiency of a given diameter hydraulic motor.  
      It is an object of this invention to utilize areas neighboring bolts to provide fluid passages for the device.  
      It is an object of this invention to utilize the inside surface of bolts to physically locate parts in respect to each other.  
      It is a further object of this invention to reduce the cost of motors.  
      It is another object of this invention to lower the heat generated by hydraulic motors.  
      It is yet another object of this invention to facilitate the manufacturer of hydraulic motors.  
      It is still a further object of this invention to lower the tolerances in hydraulic motors. 
    
    
      Other objects of the invention and a more complete understanding of the invention may be had referring to the drawings in which:  
     DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a cross-sectional side view of a hydraulic motor incorporating the invention;  
       FIG. 2  is a side view of the manifold of the motor of  FIG. 1 ;  
       FIG. 3  is an end view of the manifold of  FIG. 2 , taken along lines  3 - 3  in  FIG. 1  which side would ordinarily face the rotor of the hydraulic device;  
       FIG. 4  is an end view of the manifold of  FIG. 2 , taken along lines  4 - 4  in  FIG. 1  which side would ordinarily face the valve of the hydraulic motor;  
       FIG. 5  is a cross-sectional view of the wear plate of  FIG. 1  taken generally from lines  5 - 5  therein;  
       FIG. 6  is an end view of the bearing port section of  FIG. 1  taken generally from lines  6 - 6  therein;  
       FIG. 7  is an end view of the end cover taken from lines  7 - 7  in  FIG. 1 .  
       FIG. 8-12  are sequential cross-sectional views of the various plates utilized to make up the manifold of  FIG. 2 ; and,  
       FIG. 13  is an enlarged view of a part of  FIG. 4  detailing the areas providing fluid passages surrounding the bolts holding the device together. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      This invention relates to an improved pressure device with increased volumetric efficiency. The invention will be described in its preferred embodiment of a gerotor motor having an orbiting valve separate from the rotor.  
      This invention relates to an improved fluid passageway for a gerotor pump/motor  10  (a pump supplies fluidic power on rotation of a shaft while a motor supplies rotation of a shaft on application of fluid pressure—a single device can do both).  
      The gerotor motor  10  has a housing  11  including a bearing port section  20 , a gerotor structure  30 , a manifold  40  and an end plate  70 .  
      The housing  11  includes all of the parts of the gerotor motor  10 . Its purpose is to locate the various fixed and movable parts in their operative positions in respect to each other. It also provides for a method of locating the gerotor motor onto an external structure as well as providing for the necessary fluidic interconnections thereto.  
      The bearing port section  20  rotatively supports the driveshaft  21  in respect to the housing in addition to providing for a specific location for the two fluid ports  27 ,  28  for the device. The ports could be located otherwise if desired (including one or both in the end plate  70 ) as long as the ports communicate with the valve as hereinafter set forth.  
      The driveshaft itself  21  is a generally cylindrical shaft supported by two needle bearings  22  to the surrounding section  20 . A main seal  23  retains the hydraulic fluid within the housing  11  while a thrust bearing  24  against a shoulder of the driveshaft prevents the extrusion of the driveshaft upon the pressurization of the central cavity  26  containing the driveshaft. If the device is a closed center device such as shown in U.S. Pat. No. 5,135,269, has a case drain such as shown in U.S. Pat. No. 5,165,880 (both incorporated by reference) or otherwise has an unpressurized case the main seal requirements are reduced.  
      The ports  27 ,  28  serve to interconnect the gerotor motor to a source of pressure and return via hydraulic lines (not shown). The use of the ports on the bearing/port section  20  allow for the maintenance of the remainder of the gerotor motor without the removal of the entire unit from its associated component (such as a frame for a wheel drive or winch drive). The location also serves to physically protect such fluid interconnections from mechanical damage by locating them neighboring structural members of the associated device.  
      In the embodiment disclosed, one port  27  is interconnected to the central cavity  26  of the bearing port section  20  while the other port  28  is interconnected to a hole  25  which extends to the rear face of such section  20  (purpose later set forth— FIG. 6 . These two connections ultimately operatively connect respectively to the operative opposing sides of the valve.). Enlarged holes  29  surround each tapped bolt hole in the rear surface of the bearing section  20 . These holes  29  provide for an increased area for fluid passage about the bolts  90 . In addition the section  20  includes part of the 360° fluid connection in the remainder of the device.  
      In the embodiment disclosed, the housing  11  is 3.4″ long with a diameter of approximately 3.62″ with the seven tapped bolt holes some 0.272″ in diameter equally spaced and located on a 2.8″ bolt circle. The bolt holes themselves are approximately 1″ deep and tapped to engage the threaded end of the bolts ({fraction (5/16)}″×24 UNF thread). The threaded engagement between the bolts  90  and bearing/port section  20  retain the bolts in position with the housing  11 . The enlarged holes  29  in the housing  11  surrounding each bolt hole are ½″ diameter located on a 2.63″ bolt circle with their axis offset from the seven bolt holes. The hole  25  extending to the port  28  is approximately {fraction (5/16)}″ diameter 0.313 deep positioned approximately 600 from the lateral axis on an approximately 1.35 radius. The groove  19  is milled 0.20 deep between at least two holes  29 . Multiple segmented grooves or a continuous 360° groove could be utilized if desired.  
      The gerotor structure  30  is the main power development element for the gerotor motor  10 . The particular gerotor structure  30  disclosed includes an orbiting rotor  31  located within a fixed stator  32  as is known in the art. The internal teeth of the stator  32  are formed by cylinders  33  captured in semi-circular cavities within such stator  32 . This allows for the efficient manufacture of the stator as well as slightly increasing the mechanical efficiency of the gerotor structure. A wobblestick  34  serves to drivingly interconnect the rotor  31  to the driveshaft  21  by a toothed interconnection with each in a conventional manner.  
      The particular stator has seven holes in it approximately 0.38″ in diameter on a 2.845″ diameter bolt circle. These holes cooperate with the holes  29  in the port section  20  in order to feed fluid to the passages  43  in the later described manifold  40 . The inside extent of these holes  52  cooperate with the inside surface of the bolts  90  to physically locate the stator  32  in position in respect to the housing  11 . This is preferred in that the bolt/stator contact is in compression and/or shear in close proximity to the location of force generation (the pressure cells). This avoids the flexing unequal elongation that is present in a device having contact outside of the bolts 180° from the location of force contact. The rotor/stator side clearance is on the order of 0.001″.  
      A wear plate  35  on one side of the gerotor structure  30  and a manifold  40  on the other side of the gerotor structure serve to seal the two axial ends of the gerotor structure, thus to finish the definition of the expanding and contracting gerotor chambers located between the rotor and the stator. They also serve to distribute fluid to and from the gerotor structure.  
      The wear plate  35  is of conventional construction except for the fact that it has slots  36  extending between the bolt holes  37  therein ( FIG. 5 ). The slots  36  allow for fluid passage between and to the bolt holes  37  through the wear plate  35  (as later described). The webs  38  interrupting the slots  36  provide for structural integrity of the wear plate center area (and also allow for the convenient handling of the part). By overlaying the wear plate ( FIG. 5 ) on the bearing/port section ( FIG. 6 ) it can be seen that at the wear plate the fluid from the hole  25  is distributed for a significant distance about the circumference of the device (360° with the addition of a second groove  19 —dotted lines the bottom of  FIG. 6 ).  
      The particular wear plate is approximately 3.735″ in diameter and 0.22″ thick. A 1.2″ hole is located in its center. There are three 0.36″ width discontinuous grooves equally spaced on a 2.83″ circle around the outer circumference of the wear plate. At least one of the webs  38  between the slots  36  is preferably fluidically bypassed by the groove  19  in the housing  11  (and/or passages in manifold  40 ). The two slots  36  shown extend between the bolt holes  37  approximately for 51.5° and a third 102.8° through the full depth of the wear plate. In the embodiment disclosed there is again inside contact between the bolt holes  37  and the bolts  90  to locate the wear plate  35 .  
      The main emphasis of the invention of the present application are the fluid passages which extend through the multi-plate manifold  40  between the port  28  and the valving area  71  outside of the orbiting valve  72  contained within the endplate  70  (the valve  72  itself is orbited by a extension  39  off of the wobblestick with the central opening  74  in such valve interconnected to the other port  27  via the central cavity  26  and the passageway  42  through the center of the rotor and manifold).  
      The manifold  40  is important in the preferred gerotor motor in that it serves three major purposes:  
      The first purpose is to transfer fluid continuously from the two ports  27 ,  28  to the valving area  71  and central opening  74  of the valve  72 . This continual commutation demands an unimpeded fluid passage through the manifold via openings, preferably at least as large as the later described valving passages in order to not impede the volumetric efficiency of the gerotor motor. This dual fluid connection requires two separate sets of fluid passageways in the manifold  40 .  
      The second purpose of the manifold  40  is to interconnect the valving area  71  and central opening  74  of the valve  72  selectively to the expanding and contracting gerotor cells of the gerotor structure  30  as the device is operated. This valving operates through a single set of bi-directional passageways extending also in the manifold  40 .  
      The third purpose of the manifold is to provide physical room for the orbiting offset of the valve from the rotor  31  and the rotational axis of the driveshaft  21 .  
      In respect to the first purpose, the interconnection between the port  27  to the central opening  74  of the valve  72  in the embodiment disclosed is a simple hole  42 , which hole extends straight through the manifold  40  from one side to another. The size of this central hole is sufficient so as to not serve to impede fluid flow through the gerotor motor while at the same time being small enough so as to not interfere with either the other passages in the manifold or to interconnect the central opening  74  with the valving area  71  bi-passing the valve  72 . By having the hole in the manifold plate immediately laterally adjoining the wobblestick  34  larger than the next plate there is an increased clearance for the wobblestick (as well as an additional surface edge for the localization of the wobblestick).  
      The interconnection between the other port  28  and the valving area  71  through the manifold  40  is of a more unique configuration. A reason for this is that the passages  43  incorporate the areas  44  about the bolts  90 , intermediate areas  45  and internal areas  46 .  
      The utilization of the areas  44  surrounding the bolts  90  for the passage of fluid enables the manifold  40  to have a smaller diameter than if a separate passage(s) was incorporated outside of the diameter of the bolt circle while not compromising volumetric efficiency, physical strength and/or longevity (as separate radially offset passages might produce). In the particular embodiment disclosed, the areas are created mostly by extending the edges of the bolt holes radially of the diameter of the bolts ( FIG. 13 ). This is accomplished in the preferred embodiment by using radii different than that of the bolt spaced from the axis of such bolt to provide for areas adjacent to the outer diameter of such bolts. There is preferably always at least some contact between the bolts and the various plates that make up the manifold at the inner (and preferably also outer) sides of the bolts  90  so as to allow the bolts to physically retain the manifold  40  in place and intact against high pressure (because the manifold is typically brazed, this contact serves to strengthen the interconnections between the plates thus allowing the use of smaller surfaces for brazing between plates). In the embodiment disclosed, this contact arranges from less than 10° on a surface (as at  44   a ) to substantially 180° contact (as at  44   b ). It is preferred that each bolt include both an inside and outside contact so as to retain the associated parts in their designed position. In this respect, it is noted that while some contact is shown in all plates to all bolts, contact therebetween can be omitted to individual bolts and/or plates as long as there is sufficient contact between the totality of bolts and the entire manifold  40  so as to retain same in physical position in respect to the housing  11  and gerotor structure  30  at the desired pressure range. Again inner contact equally spaced 360° about the device is preferred so as to contain the otherwise outward forces existent in the device with a compression type load near to the generation of forces.  
      The intermediate areas  45  serve to pass the fluid through the manifold  40  in addition to aiding in equalizing the fluid flow and pressure circumferentially about the manifold by bridging the webs  38  in the wear plate  35  and other webs between passages in the manifold plates. These intermediate areas  45  preferably interconnect at the outside bolt radius in order to maximize the distance between these intermediate areas and the later described valving passages (and the pins  49 ).  
      The internal areas  46  serve to pass the fluid from the bolt circle and intermediate areas  45  to an inside area including the valving area  71  immediately surrounding the valve  72 . This facilitates the passage of fluid from the holes  44  to this valving area  71 . Preferably, the internal extent of the internal areas  46  is defined by the outer diameter of the valve  72  as it contacts the manifold  40 —any further internal extension would be covered by the valve and be of no substantive effect.  
      In all instances, preferably there is a significant overlap between the passages to the various plates to allow for the relative free passage of fluid therebetween. This allows for pressure and fluid flow equalization about the device. It is not necessary that the intermediate areas  45  be all symmetrically interconnected as long as in total they cooperate to further extend the fluid 360° about the valve  72  from the initial single hole  25  (contrast  44   c  with passage  44   d  in  FIG. 11 ).  
      The manifold itself is some 3.7″ in diameter and 0.60″ thick. The manifold is made up of a stack of eight plates pinned together by four 0.125″ diameter pins  49  located on a 2.750″ bolt circle prior to brazing. These pins localize the plates in respect to each other during the brazing operation as well as serving to allow for the radial forces to be more efficiently passed therein. In addition the various openings and passages  43 - 45  in the manifold  40  cooperated in total with the bolts  90  to physically localize the manifold  40  in respect to the housing while simultaneously creating fluid openings for the distribution of fluid from the hole  25  to the area  71  surrounding the valve  72 . This occurs because of the unimpeded areas in the various plates  50 - 54  that make up the openings in the manifold. The bolts  90  again preferably contact the inside surfaces of the manifold  40  to locate same.  
      The cell opening plate  50  is some 3.7″ in diameter and 0.075″ thick (0.150″ for the pair shown). Each plate  50  includes seven equally spaced holes some 0.322″ in diameter located on a 2.80″ bolt circle. Five of the holes are interconnected by a 0.135″ wide web beginning at a 1.475″ inside diameter. The inside connections between the holes and webs and the outside outer ends of the holes are extended to 0.188″ (from 0.158″ with 0.125″ radiused ends) to provide for a set of interior inside passages  81  and exterior outside passages  80  about these holes. As can be seen from  FIG. 13  the extension and radiusing of the ends of the holes provides for an outer passage  47  and an inner passage  48  that would not exist had the web  45  directly interconnected with holes the diameter of the bolts  90  (the holes shown are 0.325″ diameter containing 0.315″ diameter bolts both on a 2.80″ bolt circle). Two other holes have a 0.75″ extension some 0.135″ wide on the same inner diameter with 0.068″ radius ends extending bi-directionally thereof. The center hole is 0.95″ in diameter in the outer plate and 0.80″ in the inner plate.  
      The internal shift plate  51  is some 3.7″ in diameter and 0.075″ thick (0.150″ for the pair shown). The holes in the internal shift plate  51  are some 0.380″ in diameter spaced on a 2.845″ bolt circle. The seven holes are again equally spaced, again with a 0.135″ interconnecting web on a 1.475″ inner diameter and two holes with a 0.75″ extension (again with radiused inside and outside ends). The center hole is 0.80″ in diameter.  
      The connection plate  52  is 3.7″ in diameter and 0.042″ thick. It has a series of 0.380″ diameter holes on a 2.845″ bolt circle again connected by a 0.135″ wide web on a 1.475″ inner diameter and with the 0.75″ extensions (with radiuses) and a 0.80″ diameter inner hole.  
      The external shift plate  53  is 3.77″ in diameter and 0.075″ thick (0.150″ total). The plate  53  has a series of 0.380″ diameter holes spaced on a 2.845″ bolt circle. Five of the bolt holes are interconnected by a 0.172″ wide web on a 1.435″ inner diameter with radiused ends. There is an inner extension extending off of six of the bolt holes some 0.431″ wide extending inward to a 1.04″ inner radius. Two of these inward extensions are connected by a 0.19″ wide web extending outward from a 1.04″ inner diameter while a separate extension extends in respect to an additional bolt hole some 0.75″ long. All edge radii are 0.125″.  
      The valving plate  54  is 3.77″ in diameter and 0.075″ thick. It has a series of 0.380″ diameter holes located on a 2.845″ bolt circle. These holes are interconnected by a 0.175″ wide web with a 1.435″ inner diameter for the outward passages and a 0.19″ web and 1.040″ diameter for the inner passages. Again, the inward extensions are 0.43″ wide extending inward to a 1.04″ inner diameter and all edges are radiused to 0.125″.  
      The valving passages  60  are designed to minimize the restrictiveness of their opening to a single set of crossover openings  67  in the center of the manifold  40 .  
      The valve openings  61  are designed for a smooth transition between fluid connections in an orbiting valve type design. Towards this end the inner edge of a chosen valving opening blends in with the outer edge of an adjacent opening, thus to provide for a smooth transition in the valving process.  
      The external shift passages  63  and the external shift plate  53  begin with an outer section  64  which substantially matches that of the valving passages  61 . The internal section  65  of these same passages extend inwards toward the central opening  42  without a reduction in cross-sectional area while at the same time providing sufficient distance between adjacent passages that there is a proper sealing therebetween.  
      The crossover openings  67  in the connection plate  52  include the entire area which is common to both the external shift passages  63  and the later described internal shift passages  68 . These crossover openings  67  are thus the maximum cross-sectional size they can be effectively while still efficiently transferring fluid between the external shift passages  63  and the internal shift passages  68 .  
      The internal shift passages  68  in the internal shift plate  51  extend for the greatest distance they are thus the largest passages within the manifold  40 . The inner end  69  of the internal shift passages  68  match that of the crossover openings  67  while the outer ends  70  substantially replicate the expanding/contracting gerotor cells of the gerotor device. Again, these internal shift passages  68  are designed with a minimum clearance therebetween so as to maximize the size of such passages.  
      The cell openings  71  in the cell opening plate  50  include a main section  72  which is substantially centered on the expanding/contracting gerotor cells. A small additional extension  73  provides for auxiliary lubrication of the cylinders  33  in the gerotor motor by extending substantially to the center of the area off of axial ends of such cylinders  33 . Again, the size of these cell openings  71  substantially overlap the internal shift passages  6   p  so as to provide for the efficient fluid passages therebetween.  
      In order to further increase the amount of fluid passing through the manifold, the cell opening plate  50 , the internal shift plate  51  and the external shift plate  53  are used in multiples, thereby to increase the cross-sectional area of the valving passages  60  extending therein, thus to further increase the volumetric efficiency of the gerotor motor.  
      The end plate  70  completes the housing  11  by aiding to seal the area  71  surrounding the valve  72  against the manifold  40 . The end plate is substantially 3.6″ in diameter and 1.17″ long with a series of 0.315″ diameter holes on a 2.8″ bolt circle for the bolts  90 .  
      Although this invention has been described in its preferred form with a certain degree of particularity, numerous changes can be made without deviating from the following claimed invention. For example an inside contact between the bolts  50  and the various openings  43 - 45  in the manifold  40  are utilized to retain the manifold in position in respect to the remainder of the housing  11 . If desired outside contact, a combined inside/outside contact, a limited number of dedicated through bolts or other contacts could be utilized without deviating from this invention. Additional example the passages within the manifold can be modified to provide for a 360° transfer of fluid entirely within the manifold. This could be accomplished by modifying the two plates  50 ,  51  ( FIGS. 14 and 15 ) and/or the plates  53 ,  54  ( FIG. 16  or  17 ). It is not preferred to modify the cross-over plate  52  due to the single thickness limited available area in this plate. Other changes are also possible.