WO2014200762A1

WO2014200762A1 - Remanufactured hydraulic device, housing and remanufacturing method

Info

Publication number: WO2014200762A1
Application number: PCT/US2014/040702
Authority: WO
Inventors: Donald Clark; Joseph W. Louks; Robert Lovenshimer; John Charpia
Original assignee: Caterpillar Inc.
Priority date: 2013-06-11
Filing date: 2014-06-03
Publication date: 2014-12-18
Also published as: CN105308319A; US20140363316A1; CN105308319B

Abstract

Remanufacturing a variable displacement swash plate-type hydraulic device (10) includes receiving a body (12) of a used hydraulic device (10) defining first and second actuator guide bores (160, 164), at least one of which is out of specifications for guiding a swash plate linear actuator (56). The method further includes removing material forming the first and second guide bores (160, 164), and interference fitting first and second sleeves (28, 30) into the body (12) in place of the removed material. Additional material is removed from the first and second sleeves (28, 30) to form new first and second actuator guide bores (60, 64), each satisfying specifications for guiding a swash plate linear actuator (56).

Description

REMANUFACTURED HYDRAULIC DEVICE, HOUSING AND

REMANUFACTURING METHOD

Technical Field

The present disclosure relates generally to the field of

remanufacturing, and relates more particularly to installing sleeves in a hydraulic device body to form new guide bores for a swash plate linear actuator.

Background

The fields of machine component salvaging and remanufacturing have grown rapidly in recent years. Systems and components that only recently would have been scrapped are now repaired and/or refurbished and returned to service. For many years machine components have routinely been "rebuilt" and used again, but often only after the components' dimensions, operating characteristics or other features are modified out of necessity from original specs. It is more desirable in many instances for systems and components to be remanufactured to a condition as good or better than new. With this goal in mind, the development of remanufacturing strategies in certain technical areas has been rapid. In other areas, however, and in the case of certain specific parts, engineers continue to find it challenging to return components to a commercially and technically acceptable state, much less a condition identical to or better than that held in a former service life.

Chief among the challenges in successfully remanufacturing certain machine components is the difficulty in holding tolerances in a repair process. Geometric tolerancing and dimensional tolerancing are often relatively tightly specified for new parts. Where the new part consists of a casting or the like, it is often possible to machine features of interest on the new casting while held in a chuck or fixture in a single machining cell, and hence tight tolerances are more readily achievable. Machining for repair purposes and the like, however, often requires that the part be processed on multiple different machines, or with multiple different machining tools which cannot so readily be located and controlled as is the case with newly manufactured parts. For these and other reasons, successful remanufacturing strategies for many parts remain elusive. One known remanufacturing strategy for hydraulic pumps is set forth in commonly owned United States Patent No. 7,934,303 to Awwad et al.

Summary

In one aspect, a method of remanufacturing a variable

displacement swash plate-type hydraulic device includes 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. The method further includes removing material of the body forming the first actuator guide bore via machining the body while supported in a first orientation upon a fixture, and removing material of the body forming the second actuator guide bore via machining the body while supported in a second orientation upon the fixture. The method further includes 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. The method still further includes 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.

In another aspect, a remanufactured housing for a variable displacement swash plate-type hydraulic device includes 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 has 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 includes 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 another body piece of the remanufactured housing. The body piece further includes 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. The first and second actuator guide bores are 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.

In still another aspect, a remanufactured variable displacement swash plate-type hydraulic device includes 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. The hydraulic device further includes a fluid transferring mechanism having a rotatable shaft, positioned within the cavity, and a bearing positioned within the bearing bore and journaling the rotatable shaft. The body piece further includes 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. The hydraulic device further includes 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. The hydraulic device further includes 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. The linear swash plate actuator is 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.

Brief Description of the Drawings

Figure 1 is a diagrammatic view of a remanufactured hydraulic device, according to one embodiment;

Figure 2 is a sectioned view through the device of Figure 1 ;

Figure 3 is a diagrammatic view of a body piece of the device of Figures 1 and 2; Figure 4 is a diagrammatic view of the body piece at a remanufacturing stage, according to one embodiment;

Figure 5 is a sectioned diagrammatic view of the body piece at another remanufacturing stage;

Figure 6 is a sectioned view of the body piece at yet another remanufacturing stage;

Figure 7 is a sectioned view of the body piece at yet another remanufacturing stage;

Figure 8 is a sectioned view of the body piece at yet another remanufacturing stage; and

Figure 9 is a partially sectioned side view of the body piece having been remanufactured and having installed therein a linear swash plate actuator.

Detailed Description

Referring to Figure 1, there is shown a remanufactured variable displacement swash plate-type hydraulic device 10. Hydraulic device 10 may include a hydraulic pump of a type suitable for use in a hydraulic implement system or even a hydraulic propulsion system, in certain types of mobile machinery, notably wheel loaders. The present disclosure is not thusly limited, however, and other types of hydraulic devices and machinery may benefit from the remanufacturing teachings set forth herein. Hydraulic device 10 may include a body or housing 12 having a plurality of cast iron body pieces including a first body piece 14 connected to a second body piece 26. Body piece 14 has a first body piece end 18 to which is coupled an end cover 32, and a second body piece end 20 connected to second body piece 26. A side cover 34 is mounted to body piece 14 between body piece ends 18 and 20, and protects hydraulic fluid supply and control mechanisms 36 which are used to position and control a swash plate linear actuator, not shown in Figure 1, for varying displacement of hydraulic device 10 in a manner further discussed herein. Hydraulic device 10 further includes a first sleeve 28 and a second sleeve 30 each installed within body piece 14 and adapted to guide the swash plate linear actuator. Sleeves 28 and 30 may be formed from pre-hardened 4140 alloy steel, for example, harder than the cast iron of housing 12. When a used hydraulic device such as hydraulic device 10 is removed from service, disassembled, and inspected, it is often discovered that factory machined guide bores for a swash plate linear actuator are out of specifications. Standard past practice has been to scrap out of specification housings. As will be further apparent from the following description, the preparation and installation procedures for sleeves 28 and 30 contemplated herein enable hydraulic device 10 to be returned to a state at least satisfying or even exceeding original specifications for guiding a swash plate linear actuator in new devices.

Referring now also to Figure 2, there is shown a sectioned view through hydraulic device 10. It will be noted body piece 14 has formed therein a cavity 16 extending between first body piece end 18 and second body piece end 20. A fluid transferring mechanism 22 that includes a rotatable shaft 24 is received within cavity 16. Body piece 14 further has formed therein a bearing bore 38 located at first body piece end 18 and having a bearing 40 positioned therein and journaling rotatable shaft 24. Bearing bore 38 defines a longitudinal axis 42 extending between first and second body piece ends 18 and 20. At least one other bearing may be positioned within second body piece 26 and journals an opposite end of shaft 24 in a known manner. Body piece 14 further includes a mounting flange 44 located at first body piece end 18 for mounting hydraulic device 10, such as to an engine housing or intermediate mounting hardware, so as to enable shaft 24 to be directly driven via a gear train of an engine. Body piece 14 also includes a connecting flange 46 located at second body piece end 20, for connecting to another body piece of remanufactured housing 12 such as body piece 26. A plurality of bolts 48 extend through body piece 26 and into a plurality of fastener bores 50 which extend in an axial direction through connecting flange 46.

In the Figure 2 illustration, few internal components are shown within body piece 26. It will be understood by those skilled in the art, however, that hydraulic devices contemplated within the present context may include components housed within body piece 26 and also operable via the rotation of shaft 24. For instance, an impeller might be mounted to shaft 24 and rotatable within body piece 26 to transition a working fluid therethrough for various ends. As to components housed within body piece 14, in a practical implementation strategy fluid transferring mechanism 22 may include a piston and barrel assembly 52 mounted upon shaft 24 and rotatable in a conventional manner to transition fluid through housing 12. Housing 12 will also be equipped with suitable fluid inlets and fluid outlets for such purposes. In the case of hydraulic device 10 configured as a pump, rotation of piston and barrel assembly 52 may be induced via rotation of shaft 24, causing fluid to be pumped through device 10. In an alternative motor strategy, fluid pumped through device 10 or a similar but somewhat differently configured device could induce rotation of internal components, and thus cause an output shaft to rotate.

As noted above, hydraulic device 10 includes a variable displacement hydraulic device. To this end, a swash plate 54 is positioned within cavity 16 and contacts mechanism 22, in particular piston and barrel assembly 52 in a conventional manner. Those skilled in the art will be well familiar with the general manner in which changing an angle of a swash plate can change displacement of a pump or motor. In Figure 2, a swash plate linear actuator 56 is shown in a different section plane, and positioned generally behind the section plane through piston and barrel assembly 52. Actuator 56 includes a first actuator end 58 positioned within an actuator guide bore 60 formed in and defined by sleeve 28. A second actuator end 62 is positioned within an actuator guide bore 64 formed in and defined by sleeve 30. It may also be noted that sleeve 30 includes a radially projecting flange 66 and is recessed within body piece 14, as opposed to the non-recessed position of sleeve 28. Recessing of sleeve 30 can accommodate sliding motion of actuator 56 during adjusting an angle of swash plate 54. It will thus be understood that actuator 56 generally can be reciprocated back and forth, left to right in Figure 2, to adjust an angle of swash plate 54 relative axis 42 via a coupling mechanism 68 connecting between actuator 56 and swash plate 54. The necessary or desirable structures mechanically coupling actuator 56 with swash plate 54 are well known in the art.

First sleeve 28 and second sleeve 30 are interference fitted into body piece 14 in place of material removed via machining. Sleeves 28 and 30 may also be retained, or their retention enhanced, via a suitable adhesive such as Loctite® applied during installation. As noted above, when received after service in a machine system, it is common for originally designed-in actuator guide bores to have damage such as scuffing, scratches, or deformation so that they are out of round. Some of this damage may actually occur during the disassembly process, but in any event renders the corresponding actuator guide bore out of specifications for guiding a swash plate linear actuator. To return hydraulic device 10 to a state as good as or better than new, original equipment specifications must be satisfied, meaning that actuator guide bore damage must be repaired so that body piece 14 has actuator guide bores satisfying the specifications, along with all the other specifications relating to construction and functioning of hydraulic device 10.

Referring now to Figure 3, there is shown body piece 14 decoupled from the other parts of housing 12, and where internal components have been removed, and sleeves 28 and 30 installed. It may be noted that sleeve 28 is larger than sleeve 30, having a greater outer diameter dimension whereas second sleeve 30 has a lesser outer diameter dimension. The outer diameter dimension of sleeve 28 may be about 82 mm, and its axial length about 46 mm. The outer diameter dimension of sleeve 30 may be about 36 mm, the outer diameter dimension of flange 66 about 52 mm, and its axial length about 27 mm. Inner diameter dimensions are discussed below. In a practical implementation strategy, the new actuator guide bores 60 and 64 are oriented transverse to longitudinal axis 42, and are radially offset from longitudinal axis 42. As can be seen from Figure 3, an axis 70 common to sleeves 28 and 30 extends

substantially normal to axis 42 but is radially offset from axis 42. A single axis 70 is shown to illustrate the substantially coaxial orientation of sleeves 28 and 30 and thus guide bores 60 and 64. In a practical implementation strategy, first sleeve 28 and second sleeve 30 may be coaxial with one another within a total runout of about 0.006 mm or about 6 microns. Total runout is one specification for guiding actuator 56 which in many cases must be satisfied for successful return to service, often necessary to avoid damage to actuator 56 and/or its successful sliding operation. As used herein, the term "about" should be understood in the context of conventional rounding to a consistent number of significant digits. Accordingly, "about 0.006" means from 0.0055 to 0.0064. Also shown in Figure 3 is a bearing surface 69 which contacts coupling mechanism 68 when device 10 is assembled. Industrial Applicability

Referring now to Figure 4, there is shown body piece 14 as it might appear supported in a first orientation upon a fixture 175, commencing processing for installation of sleeves 28 and 30. In a practical implementation strategy, body piece 14 may be coupled with fixture 175 such that a plurality of pins in fixture 175 mate with fastener bores 50 in fiange 46. With body piece 14 supported as shown, a probe 179 coupled with a positioning mechanism 181 can be used to establish positioning coordinates for processing body piece 14 in a manner further discussed herein. Probe is shown via numeral 179 at a first probing step, and via numeral 179' at a subsequent probing step. In a practical implementation strategy, probe 179 may be used to probe a hole 176 in fixture 175, recording a Y coordinate and an X coordinate and thereby establishing an X-Y positioning plane. Hole 176 has a known correspondence with the pins in fixture 175, which in turn have a known correspondence with bores 50. This general relationship enables locating in the X-Y plane for machining. Probe 179' can than be used to record a vertical (Zi) positioning coordinate via lowering into contact with body piece 14, and in a practical implementation strategy into contact with a surface 72 extending circumferentially around an existing, old, and potentially damaged bore 160 in body piece 14. Accordingly, after probing fixture 175 and then body piece 14 a first time, positioning data may be stored for use in positioning machining tools for subsequent CNC machining.

Referring now to Figure 5, there is shown body piece 14 still supported in the first orientation upon fixture 175 and where pins 177 extend into bores 50. Also shown in Figure 5 is a machining apparatus 200 having a positioning mechanism 202 and a machining head 204, as it might appear where removing material of body piece 14 forming existing actuator guide bore 160. Mechanism 202 may include or be the same as mechanism 181 in Figure 5, but in any event will use the positioning coordinates established in the Figure 4 steps. Once material is removed from body piece 14 forming existing bore 160, body piece 14 may be decoupled from fixture 175, flipped over 180°, and hole 176 in fixture 175 probed again to re-establish the X-Y positioning plane. Body piece 14 may also be probed again to establish a new vertical (Z₂) positioning coordinate, since machining depth in existing bore 164 will typically be different from that for bore 160. Referring now to Figure 6, there is shown body piece 14 as it might appear having been flipped over, fixture 175 and body piece 14 probed a second time, and a different machining head 206 coupled to machining apparatus 200 to remove material of body piece 14 forming second existing actuator guide bore 164. It will thus be appreciated that the same X-Y positioning plane is established, based upon the probing of fixture 175 in advance of each of the steps of removing material of body piece 14. Body piece 14 is separately probed each time, for instance each time probing a surface extending circumferentially around the corresponding existing bore 160 or 164. This general procedure of re-establishing the same X and Y positioning coordinates may be understood as linking the removal of material forming the first existing guide bore 160 with the removal of material forming the second existing guide bore 164. As a result, press fitting and finish machining of sleeves 28 and 30 is facilitated as further discussed herein.

Referring now to Figure 7, there is shown body piece 14 as it might appear where first sleeve 28 and second sleeve 30 are being

simultaneously press fitted into body piece 14 in place of the corresponding removed material. A press fitting tool 300 is shown having a cylinder 302 and a rod 304. A disk 306 is mounted to an end of rod 304, and a positioning piece 307 located between disk 306 and second sleeve 30. A holding and locating assembly 308 is positioned about first sleeve 28, such that first sleeve 28 may be pushed into body piece 14 via operation of tool 300 while second sleeve 30 is pulled into body piece 14. Simultaneous press fitting of sleeves 28 and 30 is believed to assist in minimizing deviations from specified coaxial orientations of sleeves 28 and 30, while also making assembly relatively more efficient. It will be recalled that sleeve 30 has a radially projecting flange 66. During operation of tool 300, sleeve 30 may be pulled into body piece 14 until its motion stops via contact between flange 66 and body piece 14. Part of assembly 308 may contact body piece 14 to set desired press fit depth of sleeve 28. Sleeves 28 and 30 may in many instances be equipped with lubrication holes, and in a practical implementation strategy piece 307 and assembly 308 may be equipped with features for maintaining a desired orientation of the lubrication holes during press fitting sleeves 28 and 30. Spring loaded balls may be used for this purpose. Referring now to Figure 8, there is shown body piece 14 as it might appear where sleeves 28 and 30 have been installed via the procedure depicted in Figure 7, and in preparation for final machining of sleeves 28 and 30 to remove material thereof to form new first and second actuator guide bores, respectively, together satisfying specifications for guiding a swash plate linear actuator in hydraulic device 10. Body piece 14 has been again positioned upon fixture 175, fixture 175 probed, and body piece 14 also probed, thereby establishing an X-Y positioning plane, as well as vertical (Z₃) positioning coordinates. In a practical implementation strategy, a machining apparatus 400 is provided having a positioning mechanism 402, a first machining head 404 for machining sleeve 28, and a second machining head 406 for machining sleeve 30. It will be noted that removing material of sleeves 28 and 30 may thus include removing the material from the respective sleeves with different machining heads of a common machining tool. This strategy enables tolerances to be held relatively tight, and processing to be relatively efficient. In a practical implementation strategy, sleeve 30 may be machined first and sleeve 28 machined second, however the present disclosure is not thereby limited.

It will be recalled that the general probing and locating techniques discussed above enable linking the removal of material forming a first one of the existing actuator guide bores with removal of material forming a second one of the existing actuator guide bores. Such linking also enables machining of sleeve 28 to be relatively less intensive than what might otherwise be required. In other words, because the machining steps removing material of the first and second existing guide bores take place using the same X and Y positioning coordinates defined by a feature of fixture 175, the bores receiving sleeves 28 and 30 will tend to be quite close to being exactly coaxial. Sleeves 28 and 30 are machined to substantially final form prior to installation in body piece 14, and thus the final machining of sleeves 28 and 30 required to obtain the tight total runout tolerance is relatively modest. It may be noted that sleeve 30 has a single cylindrical inner surface 86. Inner surface 86 may define an inner diameter dimension prior to machining within body piece 14 of about 30 mm. Sleeve 28 includes a segmented inner surface, having a plurality of cylindrical inner surface segments 80, 82 and 84. Cylindrical inner surface 86 has a relatively lesser inner diameter dimension, and cylindrical surfaces 80, 82 and 84 have progressively larger inner diameter dimensions, and are all larger than the inner diameter dimension defined by inner surface 86. The inner diameter dimension defined by surface 80 may be about 75 mm, prior to machining within body piece 14. A chamfer 88 may be formed on an axial end of sleeve 28. It will typically be necessary to only machine inner surface 80 to result in sleeves 28 and 30, and thus bores 60 and 64, being coaxial within a total runout of about 0.006 mm as discussed above. Stated another way, specifications for guiding a swash plate linear actuator as discussed herein can be satisfied via machining only one of a plurality of inner surface segments 80, 82 and 84 of sleeve 28, typically just surface segment 80.

Referring now to Figure 9, there is shown body piece 14 with actuator 56 shown as it might appear positioned therein. First end 58 is in contact with sleeve 28 within new bore 60, and second end 62 is in contact with sleeve 30 within new bore 64. When returned to service, as actuator 56 slides back and forth within body piece 14, up or down in the Figure 9 illustration, a cutout 63 will engage with mechanisms coupling with swash plate 54 to change an angle thereof, and thus vary the displacement of hydraulic device 10. From the state shown in Figure 9, body piece 14 may be reconnected with other components of housing 12, fluid transferring mechanism 22 and other internal components placed within housing 12, and hydraulic device 10 prepared for returning to service in a machine system.

The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims.

Claims

1. A method of remanufacturing a variable displacement swash plate-type hydraulic device comprising:

receiving a body (12) of a used variable displacement swash plate-type hydraulic device defining a first and a second actuator guide bore (160, 164) each extending transverse to a longitudinal axis of the body (12), and at least one of which is out of specifications for guiding a swash plate linear actuator (56) in the hydraulic device (10);

removing material of the body (12) forming the first actuator guide bore (160) via machining the body (12) while supported in a first orientation upon a fixture;

removing material of the body (12) forming the second actuator guide bore (164) via machining the body (12) while supported in a second orientation upon the fixture (175);

interference fitting a first and a second sleeve (28, 30) into the body (12) in place of the removed material forming the first actuator guide bore (160) and the removed material forming the second actuator guide bore (164), respectively; and

removing material of the first and second sleeves (28, 30) via machining the first and second sleeves (28, 30) to form new first and second actuator guide bores (60, 64), respectively, each satisfying specifications for guiding a swash plate linear actuator (56) in the hydraulic device (10).

2. The method of claim 1 wherein the step of removing material of the first and second sleeves (28, 30) further includes removing material such that the new first and second actuator guide bores (60, 64) together satisfy a total runout specification of about 0.006 millimeters.

3. The method of claim 2 further comprising a step of linking the removal of material forming the first guide bore (60) with the removal of material forming the second guide bore (64);

wherein the step of linking further includes a step of locating an apparatus (200) for the machining of the body (12) via common positioning coordinates established in advance of each of the corresponding removing steps.

4. The method of claim 3 further comprising the steps of: establishing X and Y positioning coordinates via probing the fixture (175) a first time in advance of removing the material forming the first bore (160), and reestablishing the same X and Y positioning coordinates via probing the fixture (175) a second time in advance of removing the material forming the second bore (164);

establishing a first Z positioning coordinate for locating the apparatus (200) in the first removing step via probing a first surface (72) extending circumferentially around the first bore (160), and establishing a second Z positioning coordinate for locating the apparatus (200) in the second removing step via probing a second surface (76) extending circumferentially around the second bore (164).

5. The method of claim 4 wherein the step of removing material of the first and second sleeves (28, 30) includes machining only one of a plurality of segments (80, 82, 84) of an inner surface of the first sleeve (28) to satisfy the specifications.

6. The method of claim 2 wherein the step of interference fitting further includes simultaneously press fitting the first and second sleeves (28, 30) into the body (12);

wherein the first sleeve (28) is larger than the second sleeve (30), and wherein simultaneously press fitting further includes pushing the first sleeve (28) into the body (12) while pulling the second sleeve (30) into the body using a common press fitting tool; and

wherein the step of removing material of the first and second sleeves (28, 30) further includes removing the material with different machining heads (404, 406) of a common machining tool (402).

7. A remanufactured housing (12) for a variable displacement swash plate-type hydraulic device (10) comprising:

a body piece (14) having formed therein a cavity (16) extending between a first and a second body piece end (18, 20), for receiving a fluid transferring mechanism (22) that includes a rotatable shaft (24);

the body piece (14) further having formed therein a bearing bore (38) located at the first body piece end (18) configured to receive a bearing (40) for journaling the rotatable shaft (24) and defining a longitudinal axis (42) extending between the first and second body piece ends (18, 20);

the body piece (14) further including a mounting flange (44) located at the first body piece end (18), for mounting the hydraulic device (10), and a connecting flange (46) located at the second body piece end (20), for connecting to a second body piece (26) of the remanufactured housing (12);

the body piece (14) further including a first and a second actuator guide bore (60, 64) defined by a first and a second sleeve (28, 30) interference fitted into the body piece (14) in place of material removed via machining; and the first and second actuator guide bores (60, 64) 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 (60, 64) are positioned within the body piece (14) for guiding a swash plate linear actuator (56) coupled with the fluid transferring mechanism (22) to vary the displacement of the hydraulic device (10).

8. The remanufactured housing (12) of claim 7 wherein the first sleeve (28) has a greater outer diameter dimension, and the second sleeve (30) has a lesser outer diameter dimension;

wherein the first and second sleeves (28, 30) are coaxial with one another within a total runout of about 0.006 millimeters;

wherein the first sleeve (28) has a segmented inner surface (80, 82, 84) defining a plurality of different inner diameter dimensions;

wherein the second sleeve (30) 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 (66) recessed within the body piece (14).

9. A remanufactured variable displacement swash plate-type hydraulic device (10) comprising:

a body piece (14) having formed therein a cavity (16) extending between a first and a second body piece end (18, 20), and a bearing bore (38) located at the first body piece end (18) and defining a longitudinal axis (42) extending between the first and second body piece ends (20);

a fluid transferring mechanism (22) including a rotatable shaft (24), positioned within the cavity (16); a bearing (40) positioned within the bearing bore (38) and journaling the rotatable shaft (24);

the body piece (14) further including a mounting flange (44) located at the first body piece end (18), for mounting the hydraulic device (10), and a connecting flange (46) located at the second body piece end (20);

a first and a second sleeve (28, 30) interference fitted into the body piece (14) and defining a first and a second actuator guide bore (60. 64), respectively, the first and second actuator guide bores (60, 64) being oriented transverse to the longitudinal axis, radially offset from the longitudinal axis, and substantially coaxial with one another;

a swash plate (54) positioned within the cavity (16) and contacting the fluid transferring mechanism (22); and

a linear swash plate actuator (56) having a first actuator end (58) positioned within the first actuator guide bore (60), and a second actuator end (62) positioned within the second actuator guide bore (64), and being guided for linear movement within the first and second guide bores (60, 64) to adjust an angle of the swash plate (54) so as to vary the displacement of the hydraulic device (10).

10. The remanufactured hydraulic device (10) of claim 9 comprising a pump wherein the fluid transferring mechanism (22) includes a piston and barrel assembly (52);

wherein the first and second sleeves (28, 30) are coaxial with one another within a total runout of about 0.006 millimeters.