WO2018058100A1

WO2018058100A1 - Pin-bushing assembly for enhancing a flow of lubrication in a reciprocating mechanical system

Info

Publication number: WO2018058100A1
Application number: PCT/US2017/053420
Authority: WO
Inventors: Bodhayan DEV; Rahul Anil BIDKAR; Omprakash Samudrala; Christopher Edward Wolfe
Original assignee: General Electric Company
Priority date: 2016-09-26
Filing date: 2017-09-26
Publication date: 2018-03-29

Abstract

A pin-bushing assembly (10) for a connecting rod (12) is disclosed. The pin-bushing assembly (10) includes a connecting rod bushing (14) at least partially disposed within the connection rod (12); and a piston pin (16) at least partially disposed within the connecting rod bushing (14). One of the connecting rod bushing (14) and the piston pin (16) may include one or more segments (14a, 14b, 14c, 16a, 16b, 16c), and at least one of the connecting rod bushing (14) and the piston pin (16) includes a surface feature (26, 32, 38, 40) for enhancing delivery of lubrication at the interface between the connecting rod bushing (14) and the piston pin (16). The surface features can be, for example, circumferential lubricant grooves (26), axial grooves (32), dimples (38, 40), and the like. A connecting rod assembly (100) that includes the pin-bushing assembly (10) and an anti-rotation feature (46) is also disclosed.

Description

PIN-BUSHING ASSEMBLY FOR ENHANCING A FLOW OF LUBRICATION IN A

RECIPROCATING MECHANICAL SYSTEM

FIELD OF THE INVENTION

[0001] The invention relates, in general, to pin-bushing assemblies, and in particular to an assembly comprising a piston pin and a connecting rod bushing with surface features, such as circumferential coolant grooves, dimples, and the like, on the inner and outer diametric surfaces for enhanced delivery of lubrication during operation of a reciprocating mechanical system, such as a gas compressor, a reciprocating compressor, a piston compressor, and the like.

BACKGROUND OF THE INVENTION

[0002] Rod loading is a major consideration for the designers and operators of reciprocating mechanical systems, such as a gas compressor, a reciprocating compressor, a piston compressor, and the like. One must ascertain that the net rod load does not exceed the design limitations placed upon the reciprocating mechanical system. These limitations are determined by consideration of many stresses; the rod compressive and tensile stresses, the rod column stresses, crosshead compressive and tensile stresses, the rod and crosshead thread stresses, and the crosshead pin (i.e., wrist pin) shear and bearing (i.e., bushing) stresses. These stresses are evaluated for their strength of material integrity, including the stress at crosshead pin bushing. The crosshead pin bushing stress must be considered not only for its magnitude, but also, and more importantly, for its direction of application.

[0003] The load that is applied to the crosshead pin bushing is developed from two sources: the forces of inertia of the reciprocating piston, rod, and crosshead assembly, and the forces resulting from compression of the gas in the cylinder. The inertial load is that force that develops because of the weight (mass) of the piston, rod, and crosshead assembly (including piston rings, nuts, crosshead pin, and balance weights) being in reciprocating motion. Typically, the inertial load changes with the square of the rotative speed of the reciprocating mechanical system. One should note that the inertial load is a "reversing" load in that it changes from tension to compression (and back to tension again) during one complete rotation of the crankshaft.

[0004] The direction of the rod load has a paramount effect on the lubrication of the crosshead pin bushing. When the load is being applied to one side of the bushing, some finite amount of clearance develops on the opposite side. This clearance is filled with lubricant, such as oil, and the like, thereby lubricating and cooling that side of the bushing. A clearance must also develop on the other side of the bushing to lubricate the other side of the bushing. A reversal in the direction of application of the load must occur for this to happen. In addition, it is also evident that the magnitude and duration of this reversal must be such that a complete filling of this clearance space with lubricant can be effected. This is necessary to achieve adequate lubrication and cooling.

[0005] Reciprocating mechanical systems operating with non-reversing loads are highly subject to bushing damage. Many past instances have shown that a bushing can fail within a few minutes while operating under non-reversing loads. The damage will usually appear in the direction of the applied non-reversing load, or in the direction of the dominant load if the reversal is marginal. Thus, it is desirable to maintain sufficient lubrication in a reciprocating mechanical system while operating under non-reversing loads.

SUMMARY OF THE INVENTION

[0006] Embodiments of the invention offer new and inventive ways of providing sufficient lubrication in a reciprocating mechanical system under reversing loads and non-reversing loads. The reciprocating system includes, but is not limited to, a gas compressor, a reciprocating compressor, a piston compressor, and the like. In one embodiment, an assembly includes a piston pin (sometimes referred to as a "crosshead pin") that may be either lobed or straight, and a connecting rod bushing (sometimes referred to as a "bushing") that may be either lobed or straight. At least one of the pin and bushing includes a surface feature, such as circumferential grooves, axial grooves, dimples, and the like, configured in at least two dimensions to facilitate delivery of a lubricant, such as oil, and the like, to an interface (or radial gap) between the pin and the bushing.

[0007] In another embodiment, a connecting rod assembly comprises a crosshead; a connecting rod at least partially mounted within the crosshead; a pin-bushing assembly at least partially mounted within the connecting rod; a snap ring mounted to the pin-bushing assembly; a slot formed in the piston pin of the pin-bushing assembly, the crosshead and the snap ring; and an anti-rotation feature mounted in the slot. The anti-rotation feature, such as a key, ensures that the connecting rod bushing and the piston pin rotate relative to one another, but prevents relative movement between the piston pin and the crosshead during a compression cycle. In addition, the anti-rotation feature properly orientates the piston pin relative to the connecting rod bushing to optimize the flow of lubricant at the interface between the bushing the pin. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] While various embodiments of the invention are illustrated, the particular embodiments shown should not be construed to limit the claims. It is anticipated that various changes and modifications may be made without departing from the scope of this invention.

[0009] FIG. 1 shows a perspective view of a pin-bushing assembly and a connecting rod for a compressor according to an embodiment of the invention;

[00010] FIGS. 2A, 2B and 2C are schematic end views showing three different offset piston pin and connecting rod bushing configurations according to an embodiment of the invention;

[00011] FIGS. 2D and 2E are schematic top views showing two different offset piston pin configurations according to an embodiment of the invention;

[00012] FIG. 3 shows an enlarged front perspective view of a single segment lobed connecting rod bushing with a length, L, and a diameter, D;

[00013] FIG. 4 shows an enlarged front perspective view of a single segment lobed piston pin with a diameter, D;

[00014] FIG. 5 shows a front perspective view of a connecting rod bushing with circumferential feed holes passing through the outer diametric surface to the inner diametric surface of the bushing according to an embodiment of the invention;

[00015] FIG. 6 shows a front perspective view of a piston pin with circumferential grooves on the outer diametric surface according to an embodiment of the invention;

[00016] FIG. 7 shows a front perspective view of a connecting rod bushing with axial lubrication grooves on the inner diametric surface and circumferential feed holes according to an embodiment of the invention;

[00017] FIG. 8 shows a front perspective view of a connecting rod bushing with helical lubrication grooves on the inner diametric surface and circumferential feed holes according to another embodiment of the invention;

[00018] FIG. 9 shows an enlarged top perspective view of a three-segment pin with circumferential grooves on the outer diametric surface and at the intersection of the inner and outer segments according to an embodiment of the invention;

[00019] FIG. 10 shows an enlarged front perspective view of a three-segment bushing with helical lubrication grooves and dimples on the inner diametric surface and circumferential lubricant feed holes according to an embodiment of the invention; [00020] FIG. 11 shows an enlarged front perspective view of a three-segment pin with circumferential lubricant grooves and dimples on the outer diametric surface according to an embodiment of the invention.

[00021] FIG. 12 shows a pin-bushing assembly for a connecting rod and crosshead according to an embodiment of the invention;

[00022] FIG. 13 shows an enlarged view of an anti-rotation feature, such as a key, and the like, that maintains relative motion between the pin and the bushing according to an embodiment of the invention; and

[00023] FIG. 14 shows an enlarged view of the anti-rotation feature with a retention screw according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[00024] Referring now to FIG. 1, a pin-bushing assembly, shown generally at 10, mounted in a connecting rod 12 of a reciprocating mechanical system (not shown) is shown according to an embodiment of the invention. The pin-bushing assembly 10 includes a connecting rod bushing 14 (commonly referred to as a "bushing") at least partially disposed within the connection rod 12, and a piston pin 16 (commonly referred to as a "pin) at least partially disposed within the bushing 14. The connecting rod 12 includes a fluid port 18 at one end for delivering pressurized lubricant to the interface between the bushing 14 and the pin 16. The lubricant can any suitable lubricant for use in a reciprocating mechanical system, such as oil, and the like. The port 18 extends entirely through the connecting rod 12 such that lubricant entering the port 18 at one end of the connecting rod 12 exits the opposite end of the connecting rod 12 proximate the pin-bushing assembly 10.

[00025] FIGS. 2 A, 2B and 2C show three different combinations of full and partial offset pin- bushing configurations for the pin-bushing assembly 10. Specifically, FIG. 2A shows a combination of an offset connecting rod bushing 14 and an offset piston pin 16 in which the connecting rod bushing 14 and the piston pin 16 have one or more segments that are offset from each other by a distance, d. FIG. 2B shows a combination of a straight connecting rod bushing 14 and an offset piston pin 16 in which one or more segments of the piston pin 16 are offset by a distance, d. FIG. 2C shows a combination of an offset connecting rod bushing 14 and a straight piston pin 16 in which the one or more segments of the connecting rod bushing 14 are offset from each other by a distance, d.

[00026] FIG. 2D shows a three-segmented design of the piston pin 16. Specifically, the piston pin 16 includes a first outer segment 16a, an inner segment 16b and a second outer segment 16c offset from each other by a distance, d. FIG. 2E shows a two-segmented design of the piston pin 16. Specifically, the piston pin 16 includes an outer segment 16a and an inner segment 16b offset from each other by a distance, d. It will be appreciated that the disclosure is not limited by the number of segments 16a, 16b, 16c, and that the embodiments of the invention can be practiced with any desirable number of segments.

[00027] FIG. 3 shows an enlarged front perspective view of a single segment lobed (i.e. offset) connecting rod bushing 14 with a length, L, and a diameter, D.

[00028] FIG. 4 shows an enlarged front perspective view of a single segment lobed (i.e. offset) piston pin 16 with a diameter, D.

[00029] FIG. 5 shows a front perspective view of a connecting rod bushing 14 according to an embodiment of the invention. The bushing 14 The bushing 14 has an open ended, hollow, circumferential, cylindrical shape with a plurality of circumferential feed holes 20 extending entirely through the bushing 14 from an outer diametric surface 22 to an inner diametric surface 24. The feed holes 20 are in fluid communication with the pressurized oil feed port 18 passing through the connecting rod 12 to deliver lubricant to the interface between the bushing 14 and the pin 16. The feed holes 20 may have the same cross-sectional surface area (or diameter) or different cross- sectional surface areas (or diameters). In the illustrated embodiment, a single line of circumferential feed holes 20, spaced approximately equidistant from each other, are formed proximate a central region of the bushing 14. However, it will be appreciated that the invention is not limited by the number of lines of feed holes 20 and that the invention can be practiced with any desirable number of lines of circumferential feed holes 20.

[00030] FIG. 6 shows a front perspective view of a piston pin 16 with a plurality of circumferential grooves 26 on an outer diametric surface 28 according to an embodiment of the invention. Each circumferential groove 26 has a plurality of feed holes 27 extending from the outer diametric surface 28 to an inner diametric surface 29 of the piston pin 16 to supply lubricant, such as oil, and the like, to the interface between the piston pin 16 and the piston pin (not shown). In the illustrated embodiment, the pin 16 has two circumferential grooves 26, each groove 26 having a plurality of feed holes 27. However, it will be appreciated that the invention is not limited by the number of circumferential grooves 26 (and corresponding feed holes 27), and that the pin 16 can have any desirable number of circumferential grooves 26 and feed holes 27.

[00031] FIG. 7 shows a perspective view of a three-segment lobed (i.e. offset) connecting rod bushing 14, such as a rocking journal bearing, and the like, according to an embodiment of the invention. The bushing 14 can be coated with a low friction coating, such as M0S2, and the like. In one embodiment, the bushing 14 can be made out of an alloy developed for toughness in a harsh environment. Any suitable alloy may be used. For example, one suitable alloy is a copper-nickel-tin alloy, commercially available under the tradename ToughMet®, sold by Materion of Mayfield Heights, Ohio (httgs;/ s^n:QIL

[00032] In the illustrated embodiment, the connecting rod bushing 14 has a first outer segment 14a, an inner segment 14b and a second outer segment 14c. However, it will be appreciated that the invention is not limited by the number of segments, and that the bushing 14 can have any desirable number of segments.

[00033] As shown in FIG. 7, each feed hole 20 is in fluid communication with an axial groove 32 formed in an inner diametric surface 30 of the bushing 14. Thus, the inner diametric surface 30 of the bushing 14 includes a series of spaced apart axial grooves 32 formed in the inner diametric surface 30 of the bushing 14, with one axial groove per feed hole. The purpose of the grooves 32 is to act as a reservoir to collect a larger volume of lubricant at the interface between the bushing 14 and the pin 16. Because each feed hole 22 is spaced apart, each corresponding axial groove 32 is also spaced apart. Each axial groove 32 is positioned to align with and overlap its corresponding feed hole 22 and extend substantially parallel to a longitudinal axis 34 of the bushing 14. A width of each axial groove 32 is approximately equal to a diameter of its corresponding feed hole 22. A length of each axial groove 32 extends across a first outer segment 14a, an inner, raised segment 14b, and a second outer segment 14c, with one end of each axial groove 32 terminating in the first outer segment 14a proximate a first end of the connecting rod bushing 14, and a second opposite end of each axial groove 32 terminating in the second outer segment 14c, proximate a second opposite end of the connecting rod bushing 14.

[00034] In the illustrated embodiment, the feed holes 20 are only located in the inner segment 14b of the connecting rod bushing 14 to provide an enhanced supply of lubricant to the interface between the bushing 14 and the pin 16. However, it will be appreciated that the invention is not limited by the feed holes 20 only being located in the inner segment 14b, and that the invention can be practiced with the circumferential feed holes 20 located in any or all of the segments 14a, 14b, 14c.

[00035] In the illustrated embodiment, the axial lubrication grooves 32 are formed in all or part of all three segments 14a, 14b and 14c. However, it will be appreciated that the invention is not limited by the axial lubrication grooves 32 formed in all three segments 14a, 14b, 14c, and that the bushing 14 can be formed with axial lubrication grooves 32 formed in any desirable number of segments.

[00036] It is noted that the axial lubrication grooves 32 are not formed entirely on the inner diametric surface 30 of the bushing 14. It has been found a balance exists between delivering lubrication in a region of maximum film squeeze with the axial lubrication grooves 32, and providing lubrication whit an uninterrupted surface against which to form the film of lubrication. In other words, it was found to be advantageous to not provide the axial lubrication grooves 32 in a 45-degree to 90-degrees section of the inner diametric surface 30 of the bushing 14 where the non-reversing loads and the reversing loads are the highest.

[00037] FIG. 8 shows a perspective view of a three-segment lobed (i.e. offset) connecting rod bushing 14 with helical lubrication grooves 32 in the inner diametric surface 30 according to another embodiment of the invention. The helical lubrication grooves 32 are formed at an angle 36 with respect to the central, longitudinal axis 34 of the connecting rod bushing 14. In addition, the inner segment 14b of the connecting rod bushing 14 includes the circumferential feed holes 22 in fluid communication with the pressurized oil feed port 18 to an enhanced supply of lubricant to the interface between the connecting rod bushing 14 and the piston pin 16. In this embodiment, the helical lubrication grooves 32 are formed only on the two outer segments 14a, 14c of the connecting rod bushing 14. However, it will be appreciated that the invention is not limited by the grooves 32 formed on the two outer segments 14a, 14c, and that the invention can be practiced with the grooves 32 formed any or all of the segments.

[00038] FIG. 9 shows the three-segment lobed (i.e. offset) piston pin 16 with a plurality of circumferential grooves 26 located at the intersection of inner segment 16b and outer segments 16a, 16c for cooling and maintaining the lubricant film, and to supply lubricant to the interface between the connecting rod bushing 14 and the piston pin 16. The location of the circumferential grooves 26 on each segment 16a, 16b, 16c is such that the offset segments 14a, 14b, 14c on the connecting rod bushing 14 (see FIG. 8) do not interfere with the offset segments 16a, 16b, 16c on the pin 16 when the pin 16 is inserted into the bushing 14. The lobed piston pin 16 can be coated with a low friction coating, such as diamond-like carbon (DLC), and the like.

[00039] FIG. 10 is a front perspective view of a three-segmented lobed connecting rod bushing 14 according to an embodiment of the invention. In this embodiment, the inner diameter surface 30 of the lobed connecting rod bushing 14 includes at least one feature 38, such as a plurality of dimples, and the like, on the inner diametric surface 30 for holding lubricant, such as oil, and the like. The dimples 38 are formed on all of the three segments 14a, 14b, 14c. However, it will be appreciated that the dimples 38 can be formed on any or all of the segments 14a, 14b, 14c. The lobed connecting rod bushing 14 also includes a plurality of axial and/or helical lubrication grooves 32 on the inner diametric surface 30 to supply lubricant, such as oil, and the like, to the interface between the connecting rod bushing 14 and the piston pin 16. The plurality of of axial or helical grooves 32 on the inner diametric surface 30 are spaced so as to avoid the key load lines (not shown).

[00040] FIG. 11 is a front perspective view of a three-segmented lobed piston pin 16 according to an embodiment of the invention. In this embodiment, the outer diameter surface 28 of the three- segment lobed piston pin 16 includes one or more surface features 40, such as dimples, and the like, intended to hold lubricant, such as oil, and the like, on the outer surface 28, in addition to within the grooves 26. The purpose of the dimples 40 is to act as a reservoir for lubricant, and thereby aid in heat transfer. In addition, the lobed pin 16 includes a plurality of feed holes 27 to allow lubricant to flow from the outer diametric surface 28 to the inner surface 29 of the lobed pin 16. In the illustrated embodiment, the feed holes 27 are located within the circumferential lubricant grooves 26.

[00041] FIG. 12 shows a connecting rod assembly 100 comprising the pin-bushing assembly 10 (the piston pin 16 being omitted for clarity) mounted within the connecting rod 18, both of which are at least partially mounted within a crosshead 42 of the connecting rod assembly 100 according to an embodiment of the invention. Typically, the bushing 14 is held in place within the connecting rod 18 by means of a snap ring 44, or other well-known means in the art.

[00042] FIGS. 13 and 14 show an anti-rotation feature, for example, a key 46, to control movement of the bushing 14 relative to the pin 16 according to an embodiment of the invention. The anti- rotation feature 46 ensures that: 1) the pin 16 and bushing 14 rotate relative to one another with every compressor cycle, but prevent movement between the pin 16 and the crosshead 42, and 2) properly orientates the pin 16 relative to the bushing 14 for optimizing the flow of lubricant between the pin 16 and the bushing 14. The key 46 can be held in place by a fastener 48, such as a retention screw, and the like. The key 46 can be inserted into a slot 50 formed in the pin 16, the snap ring 44 and the crosshead 42. It is noted that a gap 52 may exist between the key 46 and the pin 16 once the key 46 is mounted in the pin 16, the snap ring 44 and the crosshead 42.

[00043] As described above, embodiments of a new, novel and inventive pin-bushing assembly for a connecting rod of a reciprocating mechanical system is disclosed. A benefit of this new pin- bushing assembly is that sufficient film thickness of a lubricant is maintained at the interface between the bushing 14 and the pin 16 during reversing loads and non-reversing loads. To accomplish this, the bushing 14 and the pin 16 may include one or more surface features, which includes, but is not limited to, the circumferential grooves 26 on the outer diametric surface 28 of the piston pin 16, the axial grooves 32 on the inner diametric surface 30 of the connecting rod bushing 14, one or more dimples 40 on the outer diametric surface 28 of the piston pin 16, and one or more dimples 38 on the inner diametric surface 30 of the connecting rod bushing 14.

[00044] In addition, an anti-rotation feature is incorporated to maintain the relative motion between the piston pin 16 (i.e., pin) and the connecting rod bushing 14 (i.e., bushing) and proper alignment therebetween. In one embodiment, the pin 16 and bushing 14 are coated with a low friction coating, such as diamond-like carbon (DLC), M0S2, and equivalents, to improve wear-resistance and assist in maintaining sufficient film thickness at the interface between the pin and bushing, during full reversing loads and non-reversing loads, which keeps the reciprocating mechanical system operational in the event of a valve failure. The disclosure includes two and three segmented offset pin-bushing configurations. Simulation results have shown that sufficient film thickness between the pin and bushing is maintained under reversing loads and non-reversing loads experienced in a reciprocating mechanical system.

[00045] Having described presently preferred embodiments the invention may be otherwise embodied within the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A pin-bushing assembly (10), comprising: a connecting rod bushing (14) at least partially disposed within a connecting rod (12); and a piston pin (16) at least partially disposed within the connecting rod bushing to form an interface therebetween, wherein at least one of the connecting rod bushing (14) and the piston pin (16) includes one or more segments (14a, 14b, 14c, 16a, 16b, 16c), and wherein at least one of the connecting rod bushing (14) and the piston pin (16) includes a surface feature (26, 32, 38, 40) for enhancing delivery of a lubricant at the interface between the connecting rod bushing (14) and the piston pin (16).

2. The pin-bushing assembly (10) of Claim 1, wherein the connecting rod bushing (14) has one or more segments offset from each other by a distance, d, and wherein the piston pin (16) has a straight configuration.

3. The pin-bushing assembly (10) of Claim 1, wherein the connecting rod bushing (14) has a straight configuration, and wherein the piston pin (16) has one or more segments offset from each other by a distance, d.

4. The pin-bushing assembly (10) of Claim 1, wherein the connecting rod bushing (14) has one or more segments (14a, 14b, 14c) offset from each other by a distance, d, and wherein the piston pin (16) has one or more segments (16a, 16b, 16c) offset from each other by the distance, d.

5. The pin-bushing assembly (10) of Claim 1, wherein the surface feature (26, 32, 38) comprises one of a circumferential groove (26) on an outer diametric surface (28) of the piston pin (16), an axial groove (32) on an inner diametric surface (30) of the connecting rod bushing (14), one or more dimples (40) on the outer diametric surface (28) of the piston pin (16), and one or more dimples (38) on the inner diametric surface (30) of the connecting rod bushing (14).

6. The pin-bushing assembly (10) of Claim 5, wherein the axial groove (32) is located on at least one of a first outer segment (14a) and a second outer segment (14b) of the connecting rod bushing (14).

7. The pin-bushing assembly (10) of Claim 5, wherein the axial groove (32) is formed at an angle (36) with respect to a central, longitudinal axis (34) of the connecting rod bushing (14).

8. The pin-bushing assembly (10) of Claim 5, wherein the axial groove (32) is formed parallel with respect to a central, longitudinal axis (34) of the connecting rod bushing (14).

9. The pin-bushing assembly (10) of Claim 5, wherein the axial groove (32) is not formed in a 45-degree to a 90-degree section of the inner diametric surface (30) of the connecting rod bushing (14).

10. The pin-bushing assembly (10) of Claim 5, wherein the one or more dimples (40) on the outer diametric surface (28) of the piston pin (16) are formed on at least one of a first outer segment (16a), an inner segment (16b) and a second outer segment (16c) of the piston pin (16).

11. The pin-bushing assembly (10) of Claim 5, wherein the one or more dimples (38) on the inner diametric surface (30) of the connecting rod bushing (14) are formed on at least one of a first outer segment (14a), an inner segment (14b) and a second outer segment (14c) of the connecting rod bushing (14).

12. The pin-bushing assembly (10) of Claim 1, wherein the connecting rod bushing (14) includes a plurality of feed holes (22) for enhancing a flow of lubricant from the connecting rod (12) to an interface between the connecting rod bushing (14) and the piston pin (16).

13. The pin-bushing assembly (10) of Claim 1, wherein the piston pin (14) includes a plurality of feed holes (22) for enhancing a flow of lubricant from the connecting rod bushing (14).

14. The pin-bushing assembly (10) of Claim 1, wherein the piston pin (16) is coated with a low friction coating.

15. The pin-bushing assembly (10) of Claim 14, wherein the low friction coating comprises diamond-like carbon (DLC).

16. The pin-bushing assembly (10) of Claim 1, wherein the connecting rod bushing (14) is coated with a low friction coating.

17. The pin-bushing assembly (10) of Claim 16, wherein the low friction coating comprises

18. A connecting rod assembly (100), comprising:

a crosshead (42);

a connecting rod (12) at least partially mounted within the crosshead (42);

the pin-bushing assembly (10) of Claim 1 at least partially mounted within the connecting rod (12);

a snap ring (44) mounted to the pin-bushing assembly (10);

a slot (50) formed in the piston pin (16) of the pin-bushing assembly (10), the crosshead (42) and the snap ring (44); and

an anti-rotation feature (46) mounted in the slot (50) for ensuring that the connecting rod bushing (14) and the piston pin (16) rotate relative to one another, but prevents relative movement between the piston pin (16) and the crosshead (42) during a compression cycle, and for properly orientating the piston pin (16) relative to the connecting rod bushing (14) to optimize a flow of lubricant at an interface between the connecting rod bushing (14) the piston pin (16).