Connecting rods for reciprocating fluid machines, and reciprocating fluid machines

Abstract

The cap is positioned relative to the connecting rod using a relatively simple configuration. [Solution] A connecting rod for a reciprocating fluid machine, comprising a large end divided circumferentially around a crankpin, and a metal bearing positioned between the crankpin and the large end and divided in half circumferentially. The large end is divided into a rod-side large end connected to a rod portion and a cap portion connected to the rod-side large end. The metal bearing is divided into an upper metal portion whose circumferential central portion is in contact with the bearing surface of the rod-side large end, and a lower metal portion whose circumferential central portion is in contact with the bearing surface of the cap portion. In the circumferential direction, the division position of the large end and the division position of the metal bearing are different.

Description

Technical Field

[0001] The present disclosure relates to a connecting rod of a reciprocating fluid machine and a reciprocating fluid machine.

Background Art

[0002] A reciprocating fluid machine including a piston provided reciprocally in a cylinder is known. In such a reciprocating fluid machine, a crankshaft and a piston are connected via a connecting rod (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The joint surface of the large end portion of the connecting rod and the cap joined to the large end portion, which is connected to the crank pin of the crankshaft, is often provided along a plane orthogonal to the extending direction of the rod portion of the connecting rod. And the positioning of the cap with respect to the large end portion is performed by a connecting rod bolt, which is a reamer bolt, for example.

[0005] However, for the convenience of assembly and disassembly of the reciprocating fluid machine, the joint surface between the large end portion of the connecting rod and the cap joined to the large end portion may be provided inclined with respect to the plane orthogonal to the extending direction of the rod portion of the connecting rod. In this case, the following points may become problems.

[0006] The large end of the connecting rod is circumferentially divided into a rod-side large end connected to the rod portion and a cap portion that is joined to the rod-side large end. The insertion hole for inserting the connecting rod bolt in the rod-side large end extends from the aforementioned joint surface (hereinafter simply referred to as "the aforementioned joint surface") in the rod-side large end toward the small end of the connecting rod. If the above-mentioned joint surface is inclined with respect to a plane perpendicular to the extending direction of the rod, one of the two joint surfaces provided on either side of the crankpin will be closer to the rod. Therefore, one of the ends of the through hole for inserting the connecting rod bolt on one of the joint surfaces, the end on the rod side, will also be closer to the rod. Therefore, it may become impossible to pass the through hole through the rod-side end to the rod-side big end, and it may become impossible to protrude the tip of the connecting rod bolt from the rod-side big end and fasten it with a nut.

[0007] Therefore, it is conceivable to screw the male threaded portion at the tip of the connecting rod bolt into the female threaded portion provided in the through hole. However, as mentioned above, since one of the joint surfaces approaches the rod portion, it may be difficult to ensure the length of the reamer portion in accordance with the position of the joint surface when trying to ensure the length of the male threaded portion of the connecting rod bolt (the length of the female threaded portion in the through hole). Therefore, positioning using a reamer bolt may be difficult.

[0008] In cases like these, where positioning using a reamer bolt (connecting rod bolt) becomes difficult, it is conceivable to position the cap relative to the big end by providing a separate positioning pin. When positioning with a pin, a pin of a certain size is required to ensure the pin's strength. However, securing space for the pin can be difficult, making pin-based positioning challenging in some cases.

[0009] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a connecting rod for a reciprocating fluid machine and a reciprocating fluid machine that can position a cap relative to a connecting rod with a relatively simple configuration. [Means for solving the problem]

[0010] (1) A connecting rod of a reciprocating fluid machine according to at least one embodiment of the present disclosure is: A connecting rod for a reciprocating fluid machine, A large end portion, which is connected to the crank pin of the crankshaft and is divided in the circumferential direction around the crank pin, A metal bearing, which is positioned between the crank pin and the big end and is split in half in the circumferential direction, Equipped with, The aforementioned large end is divided into a rod-side large end connected to the rod portion and a cap portion connected to the rod-side large end. The metal bearing is divided into an upper metal, the circumferential central portion of which is in contact with the bearing surface of the rod-side big end, and a lower metal, the circumferential central portion of which is in contact with the bearing surface of the cap portion. In the circumferential direction, the division position of the large end and the division position of the metal bearing are different. When the upper metal is positioned relative to the large end on the rod side, The lower metal is positioned relative to the upper metal, The cap portion is positioned relative to the upper metal and the lower metal, When the lower metal is positioned relative to the cap portion, The upper metal is positioned relative to the lower metal, The rod-side large end is positioned relative to the upper metal and the lower metal.

[0011] (2) A connecting rod of a reciprocating fluid machine according to at least one embodiment of the present disclosure is: A connecting rod for a reciprocating fluid machine, A large end portion, which is connected to the crank pin of the crankshaft and is divided in the circumferential direction around the crank pin, A metal bearing, which is positioned between the crank pin and the big end and is split in half in the circumferential direction, Equipped with, The aforementioned large end is divided into a rod-side large end connected to the rod portion and a cap portion connected to the rod-side large end. The metal bearing is divided into an upper metal, the circumferential central portion of which is in contact with the bearing surface of the rod-side big end, and a lower metal, the circumferential central portion of which is in contact with the bearing surface of the cap portion. In the circumferential direction, the division position of the large end and the division position of the metal bearing are different. The upper metal and the lower metal are positioned relative to each other in the circumferential direction by their end faces contacting each other in the circumferential direction. The rod-side big end and the upper and lower metals are positioned such that the rod-side big end contacts the upper and lower metals in the radial direction centered on the crankpin, thereby positioning the radial relative positions of the rod-side big end and the upper and lower metals. The cap portion and the upper metal and the lower metal are positioned radially relative to each other by the cap portion contacting the upper metal and the lower metal in the radial direction.

[0012] (3) A reciprocating fluid machine according to at least one embodiment of the present disclosure is The aforementioned crankshaft, A connecting rod as described in (1) or (2) above, having the large end connected to the crankpin, It is equipped with. [Effects of the Invention]

[0013] According to at least one embodiment of the present disclosure, a cap can be positioned with respect to a connecting rod with a relatively simple configuration.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 8 is a schematic longitudinal sectional view of a reciprocating compressor as an example of a reciprocating fluid machine according to an embodiment of the present disclosure. [Figure 2] FIG. 11 is an external view of a crankshaft according to some embodiments of a reciprocating compressor. [Figure 3] FIG. 14 is a view showing the vicinity of the large end portion of a connecting rod according to some embodiments. [Figure 4] FIG. 17 is a view showing the large end portion on the rod side and the upper metal according to an embodiment. [Figure 5] FIG. 20 is a view showing a cap portion and a lower metal according to an embodiment. [Figure 6] FIG. 23 is a view showing a cap portion and a lower metal according to other embodiments.

Modes for Carrying Out the Invention

[0015] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure thereto, but are merely illustrative examples. For example, expressions indicating relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” not only strictly represent such arrangements, but also represent a state of relative displacement with tolerances or angles and distances that can obtain the same function. For example, expressions indicating that things such as “identical”, “equal” and “homogeneous” are in an equal state not only strictly represent an equal state, but also represent a state in which there are tolerances or differences that can obtain the same function. For example, expressions describing shapes such as squares or cylinders shall not only represent geometrically precise shapes such as squares or cylinders, but also shapes that include protrusions, chamfers, etc., to the extent that the same effect can be achieved. On the other hand, expressions such as "to possess," "to be equipped with," "to have," "to include," or "to have" a single component are not exclusive expressions that exclude the existence of other components.

[0016] In the drawings, identical elements are denoted by the same reference numeral, and redundant explanations are omitted. Dimensions, angles, and other parameters in the drawings are exaggerated for illustrative purposes and may differ from actual proportions.

[0017] <1. Overview of Reciprocating Compressor 1> Figure 1 is a schematic longitudinal cross-sectional view of a reciprocating compressor 1 as an example of a reciprocating fluid machine according to one embodiment of the present disclosure. The reciprocating compressor 1 is incorporated into a refrigeration cycle (not shown) and configured to compress a refrigerant gas G. The refrigerant gas G is not particularly limited, but may be a fluorocarbon, ammonia, or carbon dioxide. The refrigeration cycle is composed of, for example, a primary refrigerant circuit and a secondary refrigerant circuit, and the reciprocating compressor 1 may be incorporated into the primary refrigerant circuit. As another example, the refrigeration cycle is composed of a high-speed refrigeration cycle and a low-speed refrigeration cycle, and the reciprocating compressor 1 may be incorporated into each of the cycles. In the following, the reciprocating compressor 1 is exemplified as a multi-cylinder reciprocating compressor having a plurality of pistons 36 and a plurality of cylinders 32, but the reciprocating compressor 1 of the present disclosure may be a single-cylinder reciprocating compressor.

[0018] The reciprocating compressor 1 comprises a housing 22, which is provided with an intake port 24 and a discharge port 26 for the refrigerant gas G. Furthermore, inside the housing 22 are an intake chamber 28 communicating with the intake port 24, a discharge chamber 30 communicating with the discharge port 26, a cylinder 32 equipped with an intake valve and a discharge valve, and a crank chamber 34 located below the cylinder 32. A piston 36 is arranged inside the cylinder 32 so as to be able to reciprocate, and the compression chamber is partitioned by the inner wall surface of the cylinder 32 and the piston 36. The compression chamber can communicate with the intake chamber 28 via the intake valve and can also communicate with the discharge chamber 30 via the discharge valve.

[0019] One end of the cylinder 32 communicates with the crank chamber 34, and a connecting rod 10, connected to the piston 36 via a piston pin (not shown), extends into the crank chamber 34. The crank chamber 34 is located below the intake chamber 28, and the two chambers are separated from each other by a partition wall 29 that forms part of the housing 22. A crankshaft 40 is rotatably positioned within the crank chamber 34, and the connecting rod 10 is connected to the crankpin 41 of the crankshaft 40. More specifically, the crankshaft 40 is rotatably supported by the housing 22 via a sliding bearing acting as a radial bearing. A sliding bearing, also acting as a radial bearing, is interposed between the connecting rod 10 and the piston 36 and crankshaft 40.

[0020] One end of the crankshaft 40 airtightly penetrates the housing 22 and is connected to a drive source located outside the housing 22. When the crankshaft 40 rotates due to the power supplied by the drive source, the piston 36 reciprocates within the cylinder 32. This causes the intake stroke, compression stroke, and discharge stroke of the refrigerant gas G to be executed repeatedly in sequence.

[0021] The reciprocating compressor 1 is configured to supply lubricating oil L to sliding parts such as radial bearings and pistons 36 during operation. Specifically, an oil storage chamber for lubricating oil L is formed at the bottom of the crank chamber 34. The reciprocating compressor 1 is equipped with an oil pump 42 that operates in conjunction with the crankshaft 40, and the lubricating oil L drawn up from the oil storage chamber by the oil pump 42 is supplied to each sliding part through oil passages provided inside or outside the housing 22. Oil passages are also formed inside the crankshaft 40, for example, as shown by dashed lines in Figure 1, and lubricating oil L can be supplied between the inner circumferential surface 17i of the metal bearing 17 (described later) and the outer circumferential surface 41o of the crankpin 41, and to the lubricating oil flow holes 16 formed in the crankshaft 40 (described later). In this embodiment, oil filters 46 and 48 for purifying the lubricating oil L are installed inside the oil storage chamber and outside the housing 22, respectively.

[0022] Figure 2 is an external view of the crankshaft 40 according to several embodiments of the reciprocating compressor 1. Figure 3 shows the vicinity of the large end of the connecting rod 10 according to several embodiments. Figure 4 shows the rod-side big end and upper metal according to one embodiment. Figure 5 shows the cap portion and the lower metal according to one embodiment. Figure 6 shows the cap portion and lower metal according to another embodiment. Note that Figure 3 omits the description of the connecting rod bolt 91 that connects the rod-side big end 11A and the cap portion 11B, which will be described later.

[0023] In some embodiments, the connecting rod 10 comprises a large end 11 connected to a crank pin 41 of a crankshaft 40, a small end 13 connected to a piston pin (not shown), a rod portion 15 connecting the large end 11 and the small end 13, and a metal bearing 17 positioned between the crank pin 41 and the large end 11, which is split in half circumferentially around the crank pin 41.

[0024] In the following description, the circumferential direction centered on the crankpin 41, that is, the central axis AXc of the crankpin 41, will also be simply referred to as the circumferential direction. Similarly, in the following description, the radial direction centered on the central axis AXc of the crankpin 41 will also be simply referred to as the radial direction, and the axial direction centered on the central axis AXc of the crankpin 41 will also be simply referred to as the axial direction. Furthermore, the radial direction of the crankpin 41 with respect to its central axis AXc extends in the direction of the plane of the paper in each of Figures 2 to 6, while the axial direction of the crankpin 41 with respect to its central axis AXc extends in the direction of the depth of the paper in each of Figures 2 to 6.

[0025] The large end portion 11 is circumferentially divided into a rod-side large end portion 11A connected to the rod portion 15 and a cap portion 11B connected to the rod-side large end portion 11A. For example, as shown in Figures 2 and 3, the dividing position Pc of the large end portion 11, that is, the dividing position Pc between the rod-side large end portion 11A and the cap portion 11B, is located circumferentially away from the plane PV that includes the central axis AXc of the crankpin 41 and is perpendicular to the extending direction of the rod portion 15 (the extending direction of the central axis AXr of the rod portion 15). This makes it possible to attach the connecting rod 10 to the crankpin 41 even when it is difficult to set the split position Pc of the big end 11 to the same position as the planar PV due to reasons such as ease of assembly when attaching the connecting rod 10 to the crankpin 41.

[0026] (Large end on rod side 11A) The rod-side big end 11A has two dividing surfaces Ps at the rod-side big end 11A with the cap portion 11B, which are two of the four dividing surfaces Ps formed at the dividing position Pc of the big end 11: a first dividing surface Ps1 on one side in the circumferential direction and a second dividing surface Ps2 on the other side in the circumferential direction. The first dividing surface Ps1 is formed closer to the rod portion 15 in the direction of extension of the rod portion 15, i.e., in the direction of extension of the central axis AXr of the rod portion 15, than the second dividing surface Ps2. In other words, the circumferential distance between the first dividing surface Ps1 along the bearing surface 11Aa of the rod-side big end 11A and the central axis AXr of the rod 15 is shorter than the circumferential distance between the second dividing surface Ps2 along the bearing surface 11Aa and the central axis AXr of the rod 15. In Figures 2 to 6, within the circumferential direction around the central axis AXc of the crankpin 41, the clockwise direction shown is considered one side, and the counterclockwise direction shown is considered the other side.

[0027] The upper metal 17A of the metal bearing 17, which will be described later, is positioned on the bearing surface 11Aa of the large end portion 11A on the rod side. The large end portion 11A on the rod side has a pair of female threaded portions 11Ab formed on either side of the crankpin 41 when viewed from the axial direction. The rod-side large end 11A and the rod 15 have lubricating oil flow holes 16 that extend through the rod-side large end 11A and the rod 15 along the extending direction of the rod 15, and connect the bearing surface 11Aa of the rod-side large end 11A with the inner circumferential surface 13a of the small end 13 (see Figure 2).

[0028] (Cap section 11B) The cap portion 11B has two dividing surfaces Ps in the cap portion 11B that are the two dividing surfaces Ps with the rod-side big end portion 11A, namely a third dividing surface Ps3 on one side in the circumferential direction and a fourth dividing surface Ps4 on the other side in the circumferential direction. The lower metal 17B of the metal bearing 17, which will be described later, is positioned on the bearing surface 11Ba of the cap portion 11B.

[0029] The cap portion 11B has a pair of bolt holes 11Bb formed on either side of the crankpin 41 when viewed from the axial direction, through which the connecting rod bolt 91 is inserted. When the cap portion 11B is connected to the rod-side big end portion 11A by the connecting rod bolt 91, the third dividing surface Ps3 comes into contact with the second dividing surface Ps2 of the rod-side big end portion 11A, and the fourth dividing surface Ps4 comes into contact with the first dividing surface Ps1 of the rod-side big end portion 11A.

[0030] (Metal bearing 17) The metal bearing 17 is divided into an upper metal 17A, in which the outer surface 17o of the rod-side big end 11A is in contact with the bearing surface 11Aa of the rod-side big end 11A in the central part of the circumferential direction, and a lower metal 17B, in which the outer surface 17o of the cap portion 11B is in contact with the bearing surface 11Ba of the cap portion 11B in the central part of the circumferential direction. The split position Pm of the metal bearing 17 lies within a plane PV that includes the central axis AXc of the crankpin 41 and is perpendicular to the extending direction of the rod portion 15. Furthermore, the division position Pm of the metal bearing 17 may be located not within the plane PV, but within a range of 40 degrees or less in the circumferential direction to one side and the other side of the plane PV. This allows the split position Pm of the metal bearing 17 to be set at a circumferential position that avoids the region where the surface pressure is relatively high between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17, thereby enabling good bearing performance. Furthermore, the regions where the surface pressure is relatively high between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17 are located in two regions relatively far from the aforementioned plane PV on one side and the other side in the extending direction of the rod portion 15, that is, two regions relatively close to the two intersection points of the central axis AXr of the rod portion 15 and the inner circumferential surface 17i of the metal bearing 17.

[0031] In some embodiments of the connecting rod 10, as shown in Figures 3 and 4, when the first dividing surface Ps1 is closer to the rod portion 15 in the extending direction of the rod portion 15 than the second dividing surface Ps2, it is preferable that one of the two end faces 17s (end face 17s1, end face 17s2) of the upper metal 17A, the end face 17s1 in the circumferential direction, protrudes from the first dividing surface Ps1 to one side in the circumferential direction. In this case, of the two end faces 17s (end face 17s1, end face 17s2) of the upper metal 17A, the end face 17s2 on the other end face in the circumferential direction is located on one side in the circumferential direction relative to the second dividing surface Ps2. In this case, of the two end faces 17s (end face 17s3, end face 17s4) of the lower metal 17B, one end face 17s3 in the circumferential direction protrudes to one side in the circumferential direction from the third dividing surface Ps3 of the cap portion 11B, and the other end face 17s4 in the circumferential direction is located to one side in the circumferential direction from the fourth dividing surface Ps4.

[0032] This allows the circumferential end face 17s1 of the upper metal 17A to be moved away from the region where the surface pressure is relatively high, which is one of two regions between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17. Furthermore, since the metal bearing 17 is split in half, as described above, one end face 17s3 of the lower metal 17B in the circumferential direction protrudes to one side in the circumferential direction from the third dividing surface Ps3 of the cap portion 11B. Therefore, one end face 17s3 of the lower metal 17B in the circumferential direction can be moved away from the region where the surface pressure is relatively high, which is one of the two regions between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17.

[0033] As described above, when the cap portion 11B is connected to the rod-side big end portion 11A by the connecting rod bolt 91, the third dividing surface Ps3 comes into contact with the second dividing surface Ps2, and the fourth dividing surface Ps4 comes into contact with the first dividing surface Ps1. In this state, the pair of circumferential end faces 17s of the upper metal 17A and the pair of circumferential end faces 17s of the lower metal 17B come into contact with each other, causing the upper metal 17A and the lower metal 17B to be slightly compressed from each other in the circumferential direction. As a result, when the cap portion 11B is connected to the rod-side big end portion 11A by the connecting rod bolt 91, the relative circumferential positions of the upper metal 17A and the lower metal 17B are positioned.

[0034] (First positioning structure 51) In the connecting rod 10 according to one embodiment shown in Figures 3 and 4, the upper metal 17A is positioned relative to the rod-side big end 11A. Specifically, for example, the connecting rod 10 according to one embodiment shown in Figures 3 and 4 includes a first positioning structure 51 that determines the position of the upper metal 17A relative to the rod-side big end 11A. In other words, in the connecting rod 10 according to one embodiment shown in Figures 3 and 4, the first positioning structure 51 includes a fitting member 63 that fits onto the rod-side big end 11A and the upper metal 17A, a first insertion hole 61 into which the fitting member 63 is inserted and which restricts the movement of the fitting member 63 at least in the circumferential direction relative to the rod-side big end 11A, and a second insertion hole 62 into which the fitting member 63 is inserted and which restricts the movement of the fitting member 63 at least in the circumferential direction relative to the upper metal 17A.

[0035] The first insertion hole 61 is a hole formed radially outward from the bearing surface 11Aa of the rod-side large end 11A, and in the example shown in Figures 3 and 4, it is a hole coaxial with the central axis AXr of the rod 15, which is also the central axis of the lubricating oil flow hole 16 in the circumferential direction. In the examples shown in Figures 3 and 4, the inner diameter of the first insertion hole 61 is preferably larger than the inner diameter of the lubricating oil flow hole 16.

[0036] The second insertion hole 62 is a bottomed hole formed so as to be recessed radially inward from the outer circumferential surface 17o of the upper metal 17A, and is formed in a position coaxial with the first insertion hole 61 when the upper metal 17A is attached to the rod-side big end 11A. In the examples shown in Figures 3 and 4, a through-hole 62a is formed at the bottom of the second insertion hole 62, extending through to the inner circumferential surface 17i of the upper metal 17A. The through-hole 62a is formed in a position coaxial with the first insertion hole 61 when the upper metal 17A is attached to the rod-side big end 11A.

[0037] The fitting member 63 is a member having a cylindrical outer surface formed to fit into the first insertion hole 61 and the second insertion hole 62. The outer diameter of the outer surface of the fitting member 63 is equal to the inner diameter of the first insertion hole 61 and the second insertion hole 62 within a predetermined tolerance range. In the examples shown in Figures 3 and 4, the fitting member 63 is a cylindrical member having a through hole 63a that penetrates the fitting member 63 radially. The through hole 63a is a communication hole that communicates with the lubricating oil flow hole 16. Furthermore, the radial insertion amount of the fitting member 63 into the upper metal 17A is smaller than the thickness of the upper metal 17A.

[0038] In some embodiments of the connecting rod 10, the fitting member 63 is fitted into the first insertion hole 61 and the second insertion hole 62, thereby preventing relative movement between the rod-side big end 11A and the fitting member 63 in the circumferential and axial directions, and preventing relative movement between the fitting member 63 and the upper metal 17A in the circumferential and axial directions. As a result, in some embodiments of the connecting rod 10, relative movement between the rod-side big end 11A and the upper metal 17A in the circumferential and axial directions is prevented. In the connecting rod 10 according to one embodiment shown in Figures 3 and 4, the lubricating oil flow hole 16, the through hole 63a of the fitting member 63, and the through hole 62a of the upper metal 17A are in communication. As a result, lubricating oil L from the oil passage formed inside the crankshaft 40 can be supplied to the lubricating oil flow hole 16.

[0039] In some embodiments of the connecting rod 10, the first insertion hole 61, the second insertion hole 62, and the fitting member 63 may be provided in positions that do not overlap with the lubricating oil flow hole 16 in the circumferential direction. In this case, the through hole 63a of the fitting member 63 does not need to be provided. When the first insertion hole 61, the second insertion hole 62, and the fitting member 63 are provided in positions that do not overlap with the lubricating oil flow hole 16 in the circumferential direction, a through hole is provided that penetrates the upper metal 17A radially and communicates with the lubricating oil flow hole 16. This allows lubricating oil L from the oil passage formed inside the crankshaft 40 to be supplied to the lubricating oil flow hole 16.

[0040] In the connecting rod 10 according to one embodiment shown in Figure 5, there is no positioning structure to restrict the relative movement of the cap portion 11B and the lower metal 17B in the circumferential direction. However, it is preferable to have a positioning structure that restricts the relative movement of the cap portion 11B and the lower metal 17B in the axial direction, which is different from the second positioning structure 52 described later.

[0041] (Second positioning structure 52) In the connecting rod 10 according to another embodiment shown in Figure 6, the lower metal 17B is positioned relative to the cap portion 11B. Specifically, for example, the connecting rod 10 according to the other embodiment shown in Figure 6 includes a second positioning structure 52 that determines the position of the lower metal 17B relative to the cap portion 11B. In other words, in the connecting rod 10 according to another embodiment shown in Figure 6, the second positioning structure 52 includes a fitting member 68 that fits onto the cap portion 11B and the lower metal 17B, a first insertion hole 66 into which the fitting member 68 is inserted and which restricts the movement of the fitting member 68 at least in the circumferential direction relative to the cap portion 11B, and which restricts the movement of the fitting member 68 at least in the circumferential direction relative to the lower metal 17B.

[0042] The first insertion hole 66 is a hole formed radially outward from the bearing surface 11Ba of the cap portion 11B.

[0043] The second insertion hole 67 is a bottomed hole formed so as to be recessed radially inward from the outer circumferential surface 17o of the lower metal 17B, and is formed in a position coaxial with the first insertion hole 66 when the lower metal 17B is attached to the cap portion 11B.

[0044] The fitting member 68 is a member having a cylindrical outer surface formed to fit into the first insertion hole 66 and the second insertion hole 67. The outer diameter of the outer surface of the fitting member 68 is equal to the inner diameter of the first insertion hole 66 and the second insertion hole 67 within a predetermined tolerance range. Furthermore, the radial insertion amount of the fitting member 68 into the lower metal 17B is smaller than the thickness of the lower metal 17B.

[0045] In the connecting rod 10 according to other embodiments, the fitting member 68 is fitted into the first insertion hole 66 and the second insertion hole 67, thereby preventing relative movement between the cap portion 11B and the fitting member 68 in the circumferential and axial directions, and preventing relative movement between the fitting member 68 and the lower metal 17B in the circumferential and axial directions. As a result, in the connecting rod 10 according to other embodiments, relative movement between the cap portion 11B and the lower metal 17B in the circumferential and axial directions is prevented.

[0046] In the connecting rod 10 according to this embodiment, the first insertion hole 66, the second insertion hole 67, and the fitting member 68 are provided at positions that overlap with the central axis AXr of the rod portion 15 in the circumferential direction, but they may also be provided at positions that do not overlap with the central axis AXr of the rod portion 15.

[0047] If the connecting rod 10 is equipped with a second positioning structure 52, it does not need to be equipped with a first positioning structure 51, but it is preferable that a positioning structure different from the first positioning structure 51 is provided for restricting the relative axial movement between the rod-side big end 11A and the upper metal 17A.

[0048] The connecting rod 10 may also include a first positioning structure 51 and a second positioning structure 52. In this case, it is preferable that the first positioning structure 51 allows for a certain degree of relative movement in the circumferential direction between the rod-side big end 11A and the upper metal 17A, or that the second positioning structure 52 allows for a certain degree of relative movement in the circumferential direction between the cap portion 11B and the lower metal 17B.

[0049] (Regarding the positioning of the rod-side big end 11A and the cap portion 11B) As described above, when the cap portion 11B is connected to the rod-side big end portion 11A by the connecting rod bolt 91, the relative circumferential positions of the upper metal 17A and the lower metal 17B are positioned. In some embodiments of the connecting rod 10, the division position Pc of the large end 11 and the division position Pm of the metal bearing 17 are different in the circumferential direction. Therefore, the outer circumferential surface 17o of either one or the other end of the upper metal 17A in the circumferential direction contacts the bearing surface 11Ba of the cap portion 11B, and the outer circumferential surface 17o of either one or the other end of the lower metal 17B in the circumferential direction contacts the bearing surface 11Aa of the rod-side large end 11A. In the examples shown in Figures 2 to 6, the outer circumferential surface 17o of one end of the upper metal 17A in the circumferential direction is in contact with the bearing surface 11Ba of the cap portion 11B, and the outer circumferential surface 17o of one end of the lower metal 17B in the circumferential direction is in contact with the bearing surface 11Aa of the rod-side large end portion 11A. This allows the radial position of the cap portion 11B relative to the rod-side large end portion 11A to be positioned via the upper metal 17A and the lower metal 17B.

[0050] Therefore, when the upper metal 17A is positioned relative to the rod-side big end 11A by the first positioning structure 51, and the cap portion 11B is connected to the rod-side big end 11A by the connecting rod bolt 91, the lower metal 17B is positioned relative to the upper metal 17A in the circumferential and radial directions, and the cap portion 11B is positioned relative to the upper metal 17A and the lower metal 17B in the radial direction. As a result, the radial relative position of the rod-side big end 11A and the cap portion 11B is positioned by the first positioning structure 51. The circumferential relative position of the rod-side big end 11A and the cap portion 11B is positioned by the third dividing surface Ps3 contacting the second dividing surface Ps2 and the fourth dividing surface Ps4 contacting the first dividing surface Ps1.

[0051] Furthermore, when the lower metal 17B is positioned relative to the cap portion 11B by the second positioning structure 52, and the cap portion 11B is connected to the rod-side big end 11A by the connecting rod bolt 91, the upper metal 17A is positioned relative to the lower metal 17B in the circumferential and radial directions, and the rod-side big end 11A is positioned relative to the upper metal 17A and the lower metal 17B in the radial direction. As a result, the radial relative position of the rod-side big end 11A and the cap portion 11B is positioned by the second positioning structure 52. The circumferential relative position of the rod-side big end 11A and the cap portion 11B is positioned by the third dividing surface Ps3 contacting the second dividing surface Ps2 and the fourth dividing surface Ps4 contacting the first dividing surface Ps1.

[0052] Furthermore, looking at the connecting rod 10 according to several embodiments from a different perspective than those described above, it can be said that the cap portion 11B is positioned relative to the rod-side big end portion 11A as follows. In other words, in the connecting rod 10 according to several embodiments, the upper metal 17A and the lower metal 17B are positioned relative to each other in the circumferential direction by their respective end faces 17s contacting each other. The rod-side big end 11A and the upper metal 17A and lower metal 17B are positioned relative to each other in the radial direction by the rod-side big end 11A contacting the upper metal 17A and lower metal 17B in the radial direction. The cap portion 11B and the upper metal 17A and lower metal 17B are positioned relative to each other in the radial direction by the cap portion 11B contacting the upper metal 17A and lower metal 17B in the radial direction.

[0053] Therefore, according to the connecting rod 10 according to some embodiments, the cap portion 11B can be positioned relatively easily relative to the rod-side big end portion 11A by the upper metal 17A and the lower metal 17B. Furthermore, according to the connecting rod 10 according to some embodiments, the need for other configurations to position the cap portion 11B relative to the rod-side big end portion 11A is reduced, thus simplifying the configuration for positioning the cap portion 11B relative to the rod-side big end portion 11A.

[0054] As an example of a reciprocating fluid machine according to several embodiments, the reciprocating compressor 1 comprises a crankshaft 40 and a connecting rod 10 having the above-described configuration, which has a large end 11 connected to a crankpin 41. This simplifies the configuration for positioning the cap portion 11B relative to the rod-side large end 11A, improving the ease of assembly of the reciprocating fluid machine. Furthermore, according to the reciprocating compressor 1 as an example of a reciprocating fluid machine according to several embodiments, the manufacturing cost of the reciprocating fluid machine can be reduced.

[0055] In some embodiments of the connecting rod 10, when the upper metal 17A is positioned relative to the rod-side big end 11A, that is, when the connecting rod 10 is equipped with a first positioning structure 51, the circumferential position of the upper metal 17A is positioned relative to the rod-side big end 11A, and the circumferential position of the lower metal 17B is positioned relative to the upper metal 17A. The position of the cap portion 11B is then positioned relative to the upper metal 17A and the lower metal 17B. As a result, the upper metal 17A and the lower metal 17B can position the radial position of the cap portion 11B relative to the rod-side big end 11A, thus simplifying the configuration for positioning the cap portion 11B relative to the rod-side big end 11A.

[0056] In some embodiments of the connecting rod 10, a first positioning structure 51 is provided between the rod-side big end 11A and the upper metal 17A, so that the upper metal 17A can be positioned relative to the rod-side big end 11A. Since the first positioning structure 51 includes a fitting member 63 that fits with the rod-side big end 11A and the upper metal 17A, the upper metal 17A can be positioned relative to the rod-side big end 11A with a relatively simple configuration.

[0057] In some embodiments of the connecting rod 10, the rod-side large end 11A has a lubricating oil flow hole 16 and a first insertion hole 61, the upper metal 17A has a second insertion hole 62, and the fitting member 63 has a through hole 63a which is a communication hole that communicates with the lubricating oil flow hole 16. This allows lubricating oil L to be supplied to the lubricating oil flow hole 16 through the through hole 63a of the fitting member 63. Furthermore, according to some embodiments of the connecting rod 10, the fitting member 63 can be fitted to the rod-side big end 11A by utilizing the lubricating oil flow hole 16, or by slight machining of the end of the lubricating oil flow hole 16 on the big end 11 side.

[0058] In some embodiments of the connecting rod 10, a second positioning structure 52 is provided between the cap portion 11B and the lower metal 17B, so that the lower metal 17B can be positioned relative to the cap portion 11B.

[0059] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate. For example, in the connecting rod 10 according to some of the embodiments described above, if the division position Pc of the large end 11 and the division position Pm of the metal bearing 17 are different in the circumferential direction, the division position Pc of the large end 11 may be located within the aforementioned plane PV, and the division position Pm of the metal bearing 17 may be located outside the aforementioned plane PV.

[0060] In the above description, the reciprocating compressor 1 was described as an example of a reciprocating fluid machine, but the connecting rod 10 described above can also be applied to connecting rods in other reciprocating fluid machines such as reciprocating engines.

[0061] The contents described in each of the above embodiments can be understood, for example, as follows: (1) A connecting rod 10 of a reciprocating fluid machine according to at least one embodiment of the present disclosure comprises a large end 11 that is connected to a crankpin 41 of a crankshaft 40 and is divided circumferentially around the crankpin 41, and a metal bearing 17 that is positioned between the crankpin 41 and the large end 11 and is divided in half circumferentially. The large end 11 is divided into a rod-side large end 11A connected to a rod-side large end 15 and a cap portion 11B connected to the rod-side large end 11A. The metal bearing 17 is divided into an upper metal 17A whose circumferential central portion is in contact with the bearing surface 11Aa of the rod-side large end 11A, and a lower metal 17B whose circumferential central portion is in contact with the bearing surface 11Ba of the cap portion 11B. In the circumferential direction, the division position Pc of the large end 11 and the division position Pm of the metal bearing 17 are different. When the upper metal 17A is positioned relative to the rod-side big end 11A, the lower metal 17B is positioned relative to the upper metal 17A, and the cap portion 11B is positioned relative to both the upper metal 17A and the lower metal 17B. When the lower metal 17B is positioned relative to the cap portion 11B, the upper metal 17A is positioned relative to the lower metal 17B, and the rod-side big end 11A is positioned relative to both the upper metal 17A and the lower metal 17B.

[0062] According to the configuration of (1) above, the cap portion 11B can be positioned relatively easily relative to the rod-side big end portion 11A by the upper metal 17A and the lower metal 17B. Furthermore, according to the configuration of (1) above, the need for other configurations to position the cap portion 11B relative to the rod-side big end portion 11A is reduced, thus simplifying the configuration for positioning the cap portion 11B relative to the rod-side big end portion 11A.

[0063] (2) In some embodiments, in the configuration of (1) above, if the upper metal 17A is positioned relative to the rod-side big end 11A, the circumferential position of the upper metal 17A is positioned relative to the rod-side big end 11A, and the circumferential position of the lower metal 17B is positioned relative to the upper metal 17A. The radial position of the cap portion 11B with respect to the crankpin 41 is positioned relative to the upper metal 17A and the lower metal 17B.

[0064] According to the configuration of (2) above, the upper metal 17A and the lower metal 17B can position the radial position of the cap portion 11B relative to the rod-side big end 11A, thus simplifying the configuration for positioning the cap portion 11B relative to the rod-side big end 11A.

[0065] (3) In some embodiments, in the configuration of (1) or (2) above, the division position Pc of the large end 11 may be located at a position circumferentially away from the plane PV that includes the central axis AXc of the crankpin 41 and is perpendicular to the extending direction of the rod portion 15.

[0066] According to the configuration of (3) above, even if it is difficult to set the division position Pc of the big end 11 to the same position as the planar PV due to reasons such as ease of assembly when attaching the connecting rod 10 to the crank pin 41, the connecting rod 10 can be attached to the crank pin 41.

[0067] (4) In some embodiments, in the configuration of (1) or (2) above, the split position Pm of the metal bearing 17 may be located within a range of 40 degrees or less in the circumferential direction to one side and the other side of the plane PV that includes the central axis AXc of the crankpin 41 and is perpendicular to the extending direction of the rod portion 15.

[0068] According to the configuration described in (4) above, the division position Pm of the metal bearing 17 can be set at a circumferential position that avoids the region where the surface pressure is relatively high between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17, thereby enabling good bearing performance.

[0069] (5) In some embodiments, in the configuration of (4) above, of the two dividing surfaces Ps between the rod-side large end 11A and the cap portion 11B, the first dividing surface Ps1 on one side in the circumferential direction is preferable to be closer to the rod portion 15 in the extending direction of the rod portion 15 than the second dividing surface Ps2 on the other side in the circumferential direction. The end (end face 17s1) on one side in the circumferential direction of the upper metal 17A is preferable to protrude from the first dividing surface Ps1 to one side in the circumferential direction.

[0070] According to the configuration in (5) above, of the two regions where the surface pressure is relatively high between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17, the upper metal 17A can be moved away from the region where the surface pressure is relatively high, and one end (end face 17s1) of the upper metal 17A in the circumferential direction can be moved away from the region where the surface pressure is relatively high. Furthermore, because the metal bearing 17 is split in half, one end (end face 17s3) of the lower metal 17B in the circumferential direction protrudes to one side in the circumferential direction from the dividing surface Ps (third dividing surface Ps3) that is further from the rod portion 15 in the extending direction of the rod portion 15, out of the two dividing surfaces (third dividing surface Ps3, fourth dividing surface Ps4) between the cap portion 11B and the rod portion side large end 11A. Therefore, one end (end face 17s3) of the lower metal 17B can be moved away from the region where the surface pressure is relatively high in the lower metal 17B, out of the two regions where the surface pressure is relatively high between the outer circumferential surface 41o of the crankpin 41 and the inner circumferential surface 17i of the metal bearing 17.

[0071] (6) In some embodiments, in the configuration of (5) above, the outer circumferential surface 17o of one end of the upper metal 17A in the circumferential direction may be in contact with the bearing surface 11Ba of the cap portion 11B. The outer circumferential surface 17o of one end of the lower metal 17B in the circumferential direction may be in contact with the bearing surface 11Aa of the rod portion large end 11A.

[0072] According to the configuration of (6) above, the outer peripheral surface 17o of one end of the upper metal 17A in the circumferential direction contacts the bearing surface 11Ba of the cap portion 11B, and the outer peripheral surface 17o of one end of the lower metal 17B in the circumferential direction contacts the bearing surface 11Aa of the rod-side big end 11A. Therefore, the radial position of the cap portion 11B with respect to the rod-side big end 11A can be positioned via the upper metal 17A and the lower metal 17B.

[0073] (7) In some embodiments, if the upper metal 17A is positioned relative to the rod-side big end 11A in any of the configurations (1) to (6) above, a first positioning structure 51 for determining the position of the upper metal 17A relative to the rod-side big end 11A may be provided.

[0074] According to the configuration described in (7) above, the upper metal 17A can be positioned relative to the rod-side big end 11A.

[0075] (8) In some embodiments, in the configuration of (7) above, the first positioning structure 51 may include a fitting member 63 that fits with the rod-side big end 11A and the upper metal 17A.

[0076] According to the configuration described in (8) above, the upper metal 17A can be positioned relative to the rod-side big end 11A with a relatively simple configuration.

[0077] (9) In some embodiments, in the configuration of (8) above, the rod-side big end 11A may have a lubricating oil flow hole 16 that penetrates the rod 15 along the extending direction of the rod 15, and a first insertion hole 61 that restricts the movement of the fitting member 63 at least in the circumferential direction relative to the rod-side big end 11A and into which the fitting member 63 is inserted. The upper metal 17A may have a second insertion hole 62 that restricts the movement of the fitting member 63 at least in the circumferential direction relative to the upper metal 17A and into which the fitting member 63 is inserted. The fitting member 63 may have a communication hole (through hole 63a) that communicates with the lubricating oil flow hole 16.

[0078] According to the configuration of (9) above, lubricating oil L can be supplied to the lubricating oil flow hole 16 through the communication hole (through hole 63a) of the fitting member 63. Furthermore, according to the configuration of (9) above, the fitting member 63 can be fitted to the rod-side big end 11A by utilizing the lubricating oil flow hole 16, or by slightly machining the end of the lubricating oil flow hole 16 on the big end 11 side.

[0079] (10) In some embodiments, if the lower metal 17B is positioned relative to the cap portion 11B in any of the configurations (1) to (9) above, a second positioning structure 52 for determining the position of the lower metal 17B relative to the cap portion 11B may be provided.

[0080] According to the configuration described in (10) above, the lower metal 17B can be positioned relative to the cap portion 11B.

[0081] (11) A connecting rod 10 of a reciprocating fluid machine according to at least one embodiment of the present disclosure comprises a large end 11 that is connected to a crankpin 41 of a crankshaft 40 and is divided circumferentially around the crankpin 41, and a metal bearing 17 that is positioned between the crankpin 41 and the large end 11 and is divided in half circumferentially. The large end 11 is divided into a rod-side large end 11A connected to a rod-side large end 15 and a cap portion 11B connected to the rod-side large end 11A. The metal bearing 17 is divided into an upper metal 17A whose circumferential central portion is in contact with the bearing surface 11Aa of the rod-side large end 11A, and a lower metal 17B whose circumferential central portion is in contact with the bearing surface 11Ba of the cap portion 11B. In the circumferential direction, the division position Pc of the large end 11 and the division position Pm of the metal bearing 17 are different. The upper metal 17A and the lower metal 17B are positioned circumferentially by the contact of their respective circumferential end faces 17s. The rod-side big end 11A is positioned radially relative to the upper metal 17A and the lower metal 17B by the contact of the rod-side big end 11A with the upper metal 17A and the lower metal 17B in the radial direction centered on the crankpin 41. The cap portion 11B is positioned radially relative to the upper metal 17A and the lower metal 17B by the contact of the cap portion 11B with the upper metal 17A and the lower metal 17B in the radial direction.

[0082] According to the configuration of (11) above, the cap portion 11B can be positioned relatively easily relative to the rod-side big end portion 11A by the upper metal 17A and the lower metal 17B. Furthermore, according to the configuration of (13) above, the need for other configurations to position the cap portion 11B relative to the rod-side big end portion 11A is reduced, thus simplifying the configuration for positioning the cap portion 11B relative to the rod-side big end portion 11A.

[0083] (12) A reciprocating fluid machine according to at least one embodiment of the present disclosure comprises a crankshaft 40 and a connecting rod 10 having any of the configurations (1) to (11) above, the connecting rod having a large end 11 connected to a crankpin 41.

[0084] According to the configuration of (12) above, the configuration for positioning the cap portion 11B relative to the rod-side big end portion 11A can be simplified, thereby improving the ease of assembly of the reciprocating fluid machine. Furthermore, according to the configuration of (12) above, the manufacturing cost of the reciprocating fluid machine can be reduced.

[0085] (13) In some embodiments, in the configuration of (12) above, the reciprocating fluid machine may be a compressor (reciprocating compressor 1) for compressing the fluid.

[0086] The configuration described in (13) above improves the ease of assembly of the reciprocating compressor. Furthermore, the configuration described in (13) above reduces the manufacturing cost of the reciprocating compressor (reciprocating compressor 1). [Explanation of Symbols]

[0087] 1. Reciprocating compressor 10 Connecting Rods 11 Big end 11A Large end on rod side 11Aa bearing surface 11Ab Female thread section 11B Cap section 11Ba bearing surface 13 Small end 15 Rod 16 Lubricating oil flow hole 17 Metal bearings 17A Upper metal 17B Lower metal 17i Inner surface 17o Outer surface 17s end face 17s1 End face 17s2 end face 17s3 end face 17s4 end face 36 pistons 40 Crankshaft 41 Crankpin 41o Outer surface 51 First positioning structure 52 Second positioning structure 61 First insertion hole 62 Second insertion hole 62a through hole 63 Fitting member 63a Through hole 66 First insertion hole 67 Second insertion hole 68 Fitting member

Claims

1. A connecting rod for a reciprocating fluid machine, A large end portion, which is connected to the crank pin of the crankshaft and is divided in the circumferential direction around the crank pin, A metal bearing, which is positioned between the crank pin and the big end and is split in half in the circumferential direction, Equipped with, The aforementioned large end is divided into a rod-side large end connected to the rod portion and a cap portion connected to the rod-side large end. The metal bearing is divided into an upper metal, the circumferential central portion of which is in contact with the bearing surface of the rod-side big end, and a lower metal, the circumferential central portion of which is in contact with the bearing surface of the cap portion. In the circumferential direction, the division position of the large end and the division position of the metal bearing are different. When the upper metal is positioned relative to the large end on the rod side, The lower metal is positioned relative to the upper metal, The cap portion is positioned relative to the upper metal and the lower metal, When the lower metal is positioned relative to the cap portion, The upper metal is positioned relative to the lower metal, The rod-side large end is positioned relative to the upper metal and the lower metal. A connecting rod for a reciprocating fluid machine.

2. When the upper metal is positioned relative to the large end on the rod side, The circumferential position of the upper metal is positioned relative to the large end on the rod side. The circumferential position of the lower metal is positioned relative to the upper metal. The radial position of the cap portion with respect to the crankpin is positioned relative to the upper metal and the lower metal. A connecting rod for a reciprocating fluid machine according to claim 1.

3. The division point of the large end is located at a position away in the circumferential direction from a plane that includes the central axis of the crankpin and is perpendicular to the extending direction of the rod portion. A connecting rod for a reciprocating fluid machine according to claim 1 or 2.

4. The division position of the metal bearing is within a range of 40 degrees or less in the circumferential direction, with respect to a plane that includes the central axis of the crankpin and is perpendicular to the extending direction of the rod portion, on both the one and the other side of the circumferential direction. A connecting rod for a reciprocating fluid machine according to claim 1 or 2.

5. Of the two dividing surfaces at the large end on the rod side with respect to the cap portion, the first dividing surface on one side in the circumferential direction is closer to the rod portion in the extending direction of the rod portion than the second dividing surface on the other side in the circumferential direction. The end of the upper metal on one side in the circumferential direction protrudes from the first dividing surface to the one side in the circumferential direction. A connecting rod for a reciprocating fluid machine according to claim 4.

6. The outer circumferential surface of one end of the upper metal in the circumferential direction contacts the bearing surface of the cap portion. The outer circumferential surface of one end of the lower metal in the circumferential direction is in contact with the bearing surface of the large end on the rod side. A connecting rod for a reciprocating fluid machine according to claim 5.

7. When the upper metal is positioned relative to the rod-side big end, the device includes a first positioning structure for determining the position of the upper metal relative to the rod-side big end. A connecting rod for a reciprocating fluid machine according to claim 1 or 2.

8. The first positioning structure includes a fitting member that fits with the rod-side large end and the upper metal. A connecting rod for a reciprocating fluid machine according to claim 7.

9. The aforementioned rod-side large end is, A lubricating oil flow hole that penetrates the rod portion along the extending direction of the rod portion, The movement of the fitting member at least in the circumferential direction relative to the large end on the rod side is restricted, and the first insertion hole into which the fitting member is inserted is provided, It has, The upper metal restricts the movement of the fitting member at least in the circumferential direction relative to the upper metal, and has a second insertion hole into which the fitting member is inserted. The fitting member has a communication hole that communicates with the lubricating oil flow hole. A connecting rod for a reciprocating fluid machine according to claim 8.

10. When the lower metal is positioned relative to the cap portion, a second positioning structure is provided for determining the position of the lower metal relative to the cap portion. A connecting rod for a reciprocating fluid machine according to claim 1 or 2.

11. A connecting rod for a reciprocating fluid machine, A large end portion, which is connected to the crank pin of the crankshaft and is divided in the circumferential direction around the crank pin, A metal bearing, which is positioned between the crank pin and the big end and is split in half in the circumferential direction, Equipped with, The aforementioned large end is divided into a rod-side large end connected to the rod portion and a cap portion connected to the rod-side large end. The metal bearing is divided into an upper metal, the circumferential central portion of which is in contact with the bearing surface of the rod-side big end, and a lower metal, the circumferential central portion of which is in contact with the bearing surface of the cap portion. In the circumferential direction, the division position of the large end and the division position of the metal bearing are different. The upper metal and the lower metal are positioned relative to each other in the circumferential direction by their end faces contacting each other in the circumferential direction. The rod-side big end and the upper and lower metals are positioned such that the rod-side big end contacts the upper and lower metals in the radial direction centered on the crankpin, thereby positioning the radial relative positions of the rod-side big end and the upper and lower metals. The cap portion and the upper and lower metals are positioned such that the cap portion contacts the upper and lower metals in the radial direction, thereby positioning the relative radial positions of the cap portion and the upper and lower metals. A connecting rod for a reciprocating fluid machine.

12. The aforementioned crankshaft, A connecting rod according to claim 1 or 2, having the large end connected to the crankpin, Equipped with Reciprocating fluid machine.

13. The aforementioned reciprocating fluid machine is a compressor for compressing fluid. The reciprocating fluid machine according to claim 12.

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