Remanufactured Hydraulic Device, Housing And Remanufacturing Method

Abstract

Remanufacturing a variable displacement swash plate-type hydraulic device includes receiving a body of a used hydraulic device defining first and second actuator guide bores, at least one of which is out of specifications for guiding a swash plate linear actuator. The method further includes removing material forming the first and second guide bores, and interference fitting first and second sleeves into the body in place of the removed material. Additional material is removed from the first and second sleeves to form new first and second actuator guide bores, each satisfying specifications for guiding a swash plate linear actuator.

What is claimed is: 
     
         1 . A method of remanufacturing a variable displacement swash plate-type hydraulic device comprising:
 receiving a body of a used variable displacement swash plate-type hydraulic device defining a first and a second actuator guide bore each extending transverse to a longitudinal axis of the body, and at least one of which is out of specifications for guiding a swash plate linear actuator in the hydraulic device;   removing material of the body forming the first actuator guide bore via machining the body while supported in a first orientation upon a fixture;   removing material of the body forming the second actuator guide bore via machining the body while supported in a second orientation upon the fixture;   interference fitting a first and a second sleeve into the body in place of the removed material forming the first actuator guide bore and the removed material forming the second actuator guide bore, respectively; and   removing material of the first and second sleeves via machining the first and second sleeves to form new first and second actuator guide bores, respectively, each satisfying specifications for guiding a swash plate linear actuator in the hydraulic device.   
     
     
         2 . The method of  claim 1  wherein the step of removing material of the first and second sleeves further includes removing material such that the new first and second actuator guide bores together satisfy a total runout specification. 
     
     
         3 . The method of  claim 2  wherein the step of removing material of the first and second sleeves includes removing material such that the new first and second actuator guide bores are coaxial within a total runout specification of about 0.006 millimeters. 
     
     
         4 . The method of  claim 2  further comprising a step of linking the removal of material forming the first guide bore with the removal of material forming the second guide bore. 
     
     
         5 . The method of  claim 4  wherein the step of linking further includes a step of locating an apparatus for the machining of the body via common positioning coordinates established in advance of each of the corresponding removing steps. 
     
     
         6 . The method of  claim 5  further comprising the steps of establishing X and Y positioning coordinates via probing the fixture a first time in advance of removing the material forming the first bore, and reestablishing the same X and Y positioning coordinates via probing the fixture a second time in advance of removing the material forming the second bore. 
     
     
         7 . The method of  claim 6  further comprising the steps of establishing a first Z positioning coordinate for locating the apparatus in the first removing step via probing a first surface extending circumferentially around the first bore, and establishing a second Z positioning coordinate for locating the apparatus in the second removing step via probing a second surface extending circumferentially around the second bore. 
     
     
         8 . The method of  claim 4  wherein the step of removing material of the first and second sleeves includes machining only one of a plurality of segments of an inner surface of the first sleeve to satisfy the specifications. 
     
     
         9 . The method of  claim 2  wherein the step of interference fitting further includes simultaneously press fitting the first and second sleeves into the body. 
     
     
         10 . The method of  claim 9  wherein the first sleeve is larger than the second sleeve, and wherein simultaneously press fitting further includes pushing the first sleeve into the body while pulling the second sleeve into the body using a common press fitting tool. 
     
     
         11 . The method of  claim 2  wherein the step of removing material of the first and second sleeves further includes removing the material with different machining heads of a common machining tool. 
     
     
         12 . A remanufactured housing for a variable displacement swash plate-type hydraulic device comprising:
 a body piece having formed therein a cavity extending between a first and a second body piece end, for receiving a fluid transferring mechanism that includes a rotatable shaft;   the body piece further having formed therein a bearing bore located at the first body piece end configured to receive a bearing for journaling the rotatable shaft and defining a longitudinal axis extending between the first and second body piece ends;   the body piece further including a mounting flange located at the first body piece end, for mounting the hydraulic device, and a connecting flange located at the second body piece end, for connecting to a second body piece of the remanufactured housing;   the body piece further including a first and a second actuator guide bore defined by a first and a second sleeve interference fitted into the body piece in place of material removed via machining; and   the first and second actuator guide bores being oriented transverse to the longitudinal axis, radially offset from the longitudinal axis, and substantially coaxial with one another, such that the first and second actuator guide bores are positioned within the body piece for guiding a swash plate linear actuator coupled with the fluid transferring mechanism to vary the displacement of the hydraulic device.   
     
     
         13 . The remanufactured housing of  claim 12  wherein the first sleeve has a greater outer diameter dimension, and the second sleeve has a lesser outer diameter dimension. 
     
     
         14 . The remanufactured housing of  claim 13  wherein the first and second sleeves are coaxial with one another within a total runout of about 0.006 millimeters. 
     
     
         15 . The remanufactured housing of  claim 14  wherein the first sleeve has a segmented inner surface defining a plurality of different inner diameter dimensions. 
     
     
         16 . The remanufactured housing of  claim 15  wherein the second sleeve has a non-segmented inner surface defining a single inner diameter dimension less than the plurality of different inner diameter dimensions, and a radially projecting end flange recessed within the body piece. 
     
     
         17 . The remanufactured housing of  claim 14  wherein the body piece further has formed therein a first set of fastener bores extending through the connecting flange in an axial direction, a second set of fastener bores distributed about the first sleeve and extending in a transverse direction, and a third set of fastener bores distributed about the second sleeve and extending in the transverse direction. 
     
     
         18 . A remanufactured variable displacement swash plate-type hydraulic device comprising:
 a body piece having formed therein a cavity extending between a first and a second body piece end, and a bearing bore located at the first body piece end and defining a longitudinal axis extending between the first and second body piece ends;   a fluid transferring mechanism including a rotatable shaft, positioned within the cavity;   a bearing positioned within the bearing bore and journaling the rotatable shaft;   the body piece further including a mounting flange located at the first body piece end, for mounting the hydraulic device, and a connecting flange located at the second body end;   a first and a second sleeve interference fitted into the body piece and defining a first and a second actuator guide bore, respectively, the first and second actuator guide bores being oriented transverse to the longitudinal axis, radially offset from the longitudinal axis, and substantially coaxial with one another;   a swash plate positioned within the cavity and contacting the fluid transferring mechanism; and   a linear swash plate actuator having a first actuator end positioned within the first actuator guide bore, and a second actuator end positioned within the second actuator guide bore, and being guided for linear movement within the first and second guide bores to adjust an angle of the swash plate so as to vary the displacement of the hydraulic device.   
     
     
         19 . The remanufactured hydraulic device of  claim 18  comprising a pump wherein the fluid transferring mechanism includes a piston and barrel assembly. 
     
     
         20 . The remanufactured hydraulic device of  claim 19  wherein the first and second sleeves are coaxial with one another within a total runout of about 0.006 millimeters.