JP2003286947A - Reciprocating compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent bearing seizure or abnormal abrasion at a piston pin bearing part to improve reliability even in severe high-compression ratio operation or HFC cooling medium environments. <P>SOLUTION: In a housing 6g of a small end side bearing cylinder part, a circumferential recessed groove 6f communicating with a fourth oil passage 6c is provided. A fifth oil passage is provided as formed of the circumferential recessed groove 6f and the housing 6g. The fifth oil passage communicates with a plurality of grooves 11 provided lengthwise of a bearing on the inner surface load side of the housing 6g. The grooves 11 are set as deflected for a similar angular pitch to the maximum swing angle &theta; of a con'rod 6A around a cylinder center axis of the small end side bearing cylinder part. Both lengthwise ends of the groove are opened, and to one opening position, the other opening position is deflected for over the pitch similar to the maximum swing angle &theta; to make a multi-spiral form. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor for compressing a gas such as a refrigerant gas or air, and more particularly to an improvement in a lubrication mechanism for a piston pin bearing portion and an improvement in bearing reliability. Is.

[0002]

2. Description of the Related Art FIG. 12 shows, for example, Japanese Patent Laid-Open No. 09-49489.
FIG. 13 is a longitudinal sectional view showing a main part of a conventional reciprocating compressor described in Japanese Patent Publication No. JP-A-2003-242, FIG. 13 is a perspective view showing the connecting rod cut in the cylinder axis direction along the central axis, and FIG. FIG. 15 is an enlarged perspective view showing the flow of lubricating oil at the small end side bearing tubular portion of the connecting rod, and FIG. 15 is an explanatory view for explaining the positional relationship between the piston pin and the connecting rod during operation. ) Is a diagram showing a positional relationship at the time of compression, and (b) is a diagram showing a positional relationship at the time of inhalation. In addition, the arrow shown by the solid line in each figure shows the flow of lubricating oil.

In each figure, 1 is a case having an oil sump 8 at the bottom, 2 is a cylinder arranged at the top of the case 1,
Reference numeral 3 denotes a crankshaft that is installed in the case 1, is rotatably supported by bearings 1a and 1b thereof, and is driven by an electric motor (not shown), and 4 is a piston slidably disposed in the cylinder 2. Reference numeral 5 denotes a piston pin inserted into and supported by the piston 4, 6 denotes a small end side bearing cylindrical portion 6a for pivotally supporting the piston pin 5 and a large end bearing for pivotally supporting the crankshaft 3. A connecting rod provided with a tubular portion 6b, an oil pump 7 for pumping the lubricating oil in an oil sump 8, 1
c is a first oil passage for communicating the oil sump 8 and the oil pump 7, 3a is a second oil passage provided in the axial center of the crankshaft 3, and 3b is a radial passage provided in the crankshaft 3 The second oil passage 3a communicates with the large-end side bearing cylinder portion 6b of the connecting rod 6, and the third oil passage 6c is provided in the rod portion of the connecting rod 6 and includes the large-end side bearing cylindrical portion 6b and the small-end side bearing cylinder. A fourth oil passage communicating with the portion 6a and a third oil passage 6d
Of the oil passage 3b and the opening of the fourth oil passage 6c, which is a first oil groove formed of a concave groove provided on the inner peripheral surface of the large-end-side bearing cylinder portion 6b so that the opening portion fits within the area. , The third oil passage 3
It serves as a passage for communicating b with the fourth oil passage 6c. 9 is on the load side of the inner peripheral surface of the small-end side bearing tubular portion 6a of the connecting rod 6,
There are a plurality of second oil grooves provided along the cylinder center axis direction at different positions in the circumferential direction at the same angular pitch as the maximum swing angle θ of the connecting rod 6, and both ends of these second oil grooves 9 are Each is open. 6e is a fifth oil passage provided in the circumferential direction of the inner surface of the small end side bearing tubular portion 6a so that the opening of the fourth oil passage 6c fits within the area. It serves as a passage for communicating with the second oil groove 9. In addition,
A bearing clearance is provided between the outer peripheral surface of the piston pin 5 and the inner peripheral surface of the small-end side bearing tubular portion 6 a of the connecting rod 6. This bearing clearance is usually 0.2 / 1000 to 1.5 / 100 with respect to the diameter of the piston pin 5.
The ratio is set to about 0.

Next, the operation of the conventional reciprocating compressor having the above construction will be described. When the crankshaft 3 rotates, the motion is transmitted to the connecting rod 6, the piston 4 moves up and down, and a relative swinging motion occurs between the piston pin 5 and the connecting rod 6. Then, the lubricating oil pressurized by the oil pump 7 is sucked up from the oil sump 8, passes through the first oil passage 1c, the second oil passage 3a, the third oil passage 3b, and the large end side. The small-end side bearing tubular portion 6 passes through the first oil groove 6d of the bearing tubular portion 6b and further through the fourth oil passage 6c.
After being guided to the plurality of second oil grooves 9 from the fifth oil passage 6e provided on the sliding surface of a, the small end side bearing cylinder is caused by the relative swing motion of the piston pin 5 and the connecting rod 6. It is supplied to the sliding surface of the portion 6a and the piston pin 5.

The positional relationship between the piston pin 5 and the connecting rod 6 during operation is as shown in FIGS. 15 (a) and 15 (b). That is, the positional relationship is as shown in FIG. 15A during compression, and the positional relationship is as shown in FIG. 15B during inhalation. Figure 15
Inside, the arrow shown by the broken line shows the force acting on the piston pin 5, and the arrow shown by the solid line shows the movement of the lubricating oil. That is,
In the compression process, a downward force acts on the piston pin 5 due to the pressure of the gas to be compressed, as shown in FIG.
The piston pin 5 moves downward within the bearing clearance. On the other hand, in the suction process, due to the negative pressure in the cylinder 2 and the inertial force of the piston 4, an upward force acts on the piston pin 5 as shown in FIG. Moving. In this way, the vertical movement of the piston pin 5 causes the lubricating oil to flow within the bearing clearance, so that the lubricating oil is supplied to the load side (bottom of the inner peripheral surface) of the inner peripheral surface of the small end side bearing tubular portion 6a. It has become.

[0006]

Generally, in the reciprocating compressor, since the small-end side bearing cylinder portion 6a is in a swing motion, an oil film is hard to be formed and it is often operated below the boundary lubrication region. Further, since the amount of oil flowing through the bearing clearance of the small end side bearing tubular portion 6a is limited, the sliding contact portion of the piston pin 5 is likely to run out of oil. Particularly when performing a high compression ratio operation, the pressure in the cylinder 2 is kept high even during the suction process by the action of the re-expansion gas, so that the downward gas pressure acts on the piston pin 5. Therefore, the piston pins 5 cannot be moved alternately in the vertical direction within the bearing clearance, the lubricating oil does not flow, and oil runs out on the sliding surface load side of the small end side bearing cylinder part 6a, and the small end side bearing cylinder part There is a problem that seizure and abnormal wear occur at 6a. In particular, HFC (Hydro Fi
uoro Carbon) When operating at high compression ratio in a refrigerant environment,
In addition to deterioration of lubricity, due to high compression ratio operation, insufficient circulation due to low circulation amount causes abnormalities in the piston pin 5 and the small end side bearing cylinder 6a due to an increase in oil temperature in the compressor, especially in the oil sump and in the bearing. It is easily worn and eventually seized.

Therefore, in the above-mentioned conventional example, as a means for positively supplying the small end side bearing tubular portion 6a, the oil in the oil sump 8 is passed through the large end side bearing tubular portion 6b and the small end side bearing tubular portion 6a. Of the plurality of second oil passages extending parallel to the cylinder center axis direction of the small end side bearing cylinder portion from the fifth oil passage 6e.
The oil is supplied to the oil groove 9.

However, in the case where the oil is supplied to the plurality of second oil grooves 9 having openings at both ends extending parallel to the cylinder center axis direction of the small end side bearing cylinder portion 6a, the positive oil is positively provided. Although oil can be supplied, hydraulic pressure is not generated in the second oil groove portion 9 in the entire longitudinal direction of the small end bearing cylinder during the swing motion of the small end bearing cylinder portion 6a. Therefore, during the swing motion, a position where an oil film is not formed is generated between the second oil grooves 9, the oil film distribution of the entire bearing becomes unstable, and the total hydraulic pressure also decreases, so that sufficient bearing load capacity can be obtained. Absent.

Further, since the circumferential relative position between the piston pin 5 and the piston 4 is not normally regulated, when the rotational movement of the crankshaft 3 is transmitted to the piston 4 via the connecting rod 6, the swing movement thereof. Is transmitted through between the piston 4 and the piston pin 5, and between the piston pin 5 and the small end side bearing tubular portion 6a. In other words, since the bearing sliding length due to the swing motion of the connecting rod 6 is divided between the piston 4 and the piston pin 5 and between the piston pin 5 and the small end side bearing cylinder portion 6a, the piston pin 5 and the small end side bearing cylinder are separated. The position of the portion 6a is not stable, and the sliding length (swing angle) between the piston pin 5 and the small end side bearing tubular portion 6a, which is conventionally required, is reduced, so that not only the oil film and the hydraulic pressure are reduced but also
Originally, the unnecessary piston 4 and the piston pin 5 slide, which causes abnormal wear between the piston 4 and the piston pin 5.

A technical object of the present invention is to prevent the bearing seizure and abnormal wear of the piston pin bearing portion even under severe high compression ratio operation and HFC refrigerant environment, and to improve reliability. is there.

[0011]

A reciprocating compressor according to claim 1 of the present invention has the following configuration.
That is, a case having an oil sump at the bottom, a cylinder arranged in the case, a crankshaft pivotally supported in the case, a piston slidably arranged in the cylinder, and a piston. A piston pin inserted into and supported by the shaft, a small-end side bearing tubular part that pivotally supports the piston pin at a predetermined swing angle, and a large-end side bearing tubular part that pivotally supports the crankshaft. Connecting rod,
An oil pump for pumping the lubricating oil in the oil sump, a first oil passage for communicating the oil sump with the oil pump, and a second oil passage provided at the axial center of the crankshaft and communicating with the discharge side of the oil pump. And a third oil passage that connects the second oil passage provided on the crankshaft with the large end side bearing portion,
In a reciprocating compressor having a fourth oil passage provided inside the connecting rod and communicating the large end side bearing portion and the small end side bearing portion, a fourth oil passage is provided in a housing of the small end side bearing tubular portion. A circumferential groove that communicates with the circular groove, and a fifth oil passage formed by the circumferential groove and the housing, and the fifth oil passage and the bearing longitudinal direction provided on the inner surface load side of the housing. The plurality of grooves are communicated with each other, and the plurality of grooves are set so as to be offset by the same angle pitch as the maximum swing angle θ of the connecting rod about the cylinder center axis of the small end side bearing cylinder portion, and the groove longitudinal ends are While opening, the maximum swing angle θ
It is formed in a multi-row spiral shape by shifting the same pitch or more.

Further, in a reciprocating compressor according to a second aspect, the surface hardness of the piston pin according to the first aspect is Hv> 1000.

A reciprocating compressor according to a third aspect of the present invention has the piston and the piston pin of the first or second aspect fixed.

A reciprocating compressor according to a fourth aspect of the present invention has the following structure. That is,
A case with an oil sump at the bottom, a cylinder arranged in the case, a crankshaft pivotally supported in the case, a piston slidably arranged in the cylinder, and a piston A connecting rod provided with a supported piston pin, a small end side bearing cylinder portion that pivotally supports the piston pin at a predetermined swing angle, and a large end side bearing cylinder portion that pivotally supports the crankshaft. In the reciprocating compressor having, the surface hardness of the piston pin is H
v> 1000 is set.

A reciprocating compressor according to a fifth aspect of the present invention is such that the piston and the piston pin of the fourth aspect are fixed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Hereinafter, the present invention will be described with reference to the illustrated embodiments. FIG. 1 is a vertical cross-sectional view showing an essential part of a reciprocating compressor according to claim 1 of the present invention, and FIG. 2 is a perspective view showing a connecting rod of the reciprocating compressor in a tubular axial direction along a central axis. ) Is a diagram showing a state before the bearing metal is press-fitted into the small-end side bearing tubular portion, (b) is a diagram after the bearing metal is press-fitted into the small-end side bearing tubular portion, and FIG. FIG. 3 is an enlarged perspective view showing the end side bearing tubular portion, (a) showing a state before supplying lubricating oil to the small end side bearing tubular portion,
5B is a diagram showing the flow of the lubricating oil in the small end side bearing tubular portion, FIG. 4 is a partial sectional view of the connecting rod small end side bearing tubular portion for explaining the shape of the groove formed in the bearing metal, FIG. 6A and 6B are explanatory views for explaining the positional relationship between the piston pin and the connecting rod during operation, FIG. 6A is a diagram showing the positional relationship during compression, FIG. 6B is a diagram showing the positional relationship during suction, and FIG. It is explanatory drawing which shows the effect by this embodiment compared with a prior art example, and the arrow shown by the solid line in each figure shows the flow of lubricating oil. In each figure, the same reference numerals are attached to the portions corresponding to the conventional ones.

In FIGS. 1 to 5, 1 is a case, 2 is a cylinder, 3 is a crankshaft, 4 is a piston, 5 is a piston pin, 6A is a connecting rod, and 6g is a small end bearing housing composed of a small end side bearing cylinder. , 6b is a large end side bearing tubular portion, 7 is an oil pump, and 8 is an oil sump. Also, 1c
Is a first oil passage that connects the oil sump 8 and the oil pump 7,
3a is a second oil passage provided in the axial center portion of the crankshaft 3, and 3b is provided in the crankshaft 3 in the radial direction to connect the second oil passage 3a and the large-end side bearing tubular portion 6b of the connecting rod 6A. A third oil passage communicating with the connecting rod 6c is a connecting rod 6
A fourth oil passage provided on the rod portion of A for communicating the large end side bearing tubular portion 6b with the small end bearing housing 6g, and 6d is an opening of the third oil passage 3b and an opening of the fourth oil passage 6c. The third oil passage 3b and the fourth oil passage 6c are a first oil groove formed of a concave groove provided on the inner peripheral surface of the large end side bearing tubular portion 6b so that the portion fits in the area. It becomes a passage for communication. 6
f is a circumferential groove formed in the inner surface circumferential direction of the small end bearing housing 6g so that the opening of the fourth oil passage 6c fits in the area, and 10 is inserted into the small end bearing housing 6g of the connecting rod 6A by press fitting or the like, The bearing metal is fixed, and the outer peripheral surface thereof and the circumferential groove 6f on the inner peripheral surface of the small end bearing housing form a fifth oil passage. Reference numeral 11 denotes a plurality of grooves formed on the inner surface load side of the bearing metal 10, which are provided at the same angle pitch as the maximum swing angle θ of the connecting rod 6A about the cylinder center axis of the small end bearing housing 6g, and open at both longitudinal ends. In addition, the other opening position is shifted from the one opening position by the same pitch as the maximum swing angle θ and is set in a multi-row spiral shape. That is, in the AA cross section of FIG. 4, one opening 11 a of the plurality of grooves 11 is formed.
Are set by shifting the positions of adjacent ones in the circumferential direction at a swing angle θ pitch interval, and on the opposite side CC
On the cross-sectional side, the openings 11c of the plurality of grooves 11 are also set so that the positions of adjacent ones are displaced in the circumferential direction at swing angle θ pitch intervals. Furthermore, each groove 11 has a cross section AA.
It is formed by twisting by the swing angle θ in the bearing rotation direction at the side opening position and the cross-section CC side opening position. Reference numeral 11b in FIG. 3 is a communication hole that is provided in the bearing metal 10 and that connects the circumferential groove 6f that forms the fifth oil passage and the plurality of grooves 11.

Next, the operation of the reciprocating compressor of this embodiment will be described with reference to FIGS. The arrows shown by the solid lines in each figure indicate the flow of the lubricating oil.
First, when the crankshaft 3 rotates, the connecting rod 6
The motion is transmitted to A, the piston 4 moves up and down, and a relative swing motion occurs between the piston pin 5 and the connecting rod 6A. Then, the lubricating oil pressurized by the oil pump 7 is sucked up from the oil sump 8 and the first oil passage 1
c through the second oil passage 3a and the third oil passage 3b, through the first groove 6d of the large-end side bearing tubular portion 6b, further through the fourth oil passage 6c, and the small-end bearing housing 6g. A plurality of spiral spiral grooves 11 on the inner circumference side of the bearing metal, passing through the circumferential recessed groove 6f formed in the portion and the communication hole 11b of the bearing metal 10.
To lubricate the load side of the inner peripheral surface of the bearing metal 10. After lubrication, the lubricating oil is a plurality of grooves 11 and bearing metal 1.
0 and the bearing clearance formed by the piston pin 5 and then returns to the oil sump 8.

As described above, in the reciprocating compressor of the present embodiment, the spiral groove 11 is formed on the inner surface of the bearing metal 10 on the load side, and the maximum swing of the connecting rod 6A is centered on the cylinder center axis of the small end bearing housing 6g. Since a plurality of bearings are provided in the circumferential direction at the same angular pitch as the dynamic angle θ, the swing motion of the connecting rod 6A allows continuous lubrication over the entire load side of the sliding surface of the piston pin 5.

The plurality of grooves 11 provided on the load-side inner surface of the bearing metal 10 are open at both longitudinal ends, and are formed by twisting one opening position by the maximum swing angle θ with respect to the other opening position. Therefore, the effect shown in FIG. 6 is obtained. In FIG. 6, the lower stage is a development view of the small end bearing housing, the middle stage is a hydraulic pressure distribution generated during operation in the BB cross section of FIG. 4, and the upper stage is a total hydraulic pressure distribution in the cylinder center axis direction of the small end bearing housing. A comparative example (conventional example) is shown on the left side of each stage, and this embodiment is shown on the right side. As is clear from FIG. 6, the hydraulic pressure generated at a certain circumferential cross section (for example, the middle BB cross section) becomes 0 at the groove portion, and the maximum hydraulic pressure is generated between the grooves. The hydraulic pressure formation in each cross section viewed only from this point does not significantly differ between the comparative example and the present embodiment.
However, since the actual bearing load capacity (oil film thickness formed by the oil pressure distribution) is determined by the total (integrated value) oil pressure in the direction of the cylinder center axis of the bearing, the groove specifications of the comparative example (straight groove) However, in the groove specification (multi-spiral groove) of the present embodiment, the bearing portion (contact surface portion without groove) is always provided in the small end bearing housing, that is, in the cylinder center axis direction of the bearing metal 10. Exists. for that reason,
During the swing motion, the bearing surface is always present without being blocked, and a stable oil film is formed without interruption of hydraulic pressure. Therefore, the total hydraulic pressure is increased, the bearing load capacity is increased, and the bearing characteristics are improved.

Further, since the spiral groove 11 is open at both longitudinal ends, the lubricating oil which is supplied into the bearing clearance and whose temperature is raised by the frictional heat due to the sliding is immediately discharged to the outside of the bearing, The internal temperature does not rise and is always cooled with lubricating oil. Therefore, the high compression ratio operation in which the piston pin 5 does not move vertically and the HFC with poor self-lubricating property
Even in a refrigerant atmosphere, a stable oil film and oil pressure can be obtained without running out of oil, and friction heat due to swing motion can be constantly removed by lubricating oil, preventing temperature rise inside the bearing. can do. As a result, seizure and abnormal wear in the small end bearing housing 6g can be prevented, and a highly reliable reciprocating compressor can be obtained.

Embodiment 2. FIG. 7 shows claims 1 and 2 of the present invention.
FIG. 8 is a vertical cross-sectional view showing a small-end side bearing tubular portion, which is a main part of the reciprocating compressor according to the present invention. FIG. 8 is a compressor under a high compression ratio condition using HFC refrigerant, which is performed to confirm the effect of this embodiment. 8 is a graph showing a result of a durability test, and in FIG. 7, parts corresponding to those in the above-described first embodiment are denoted by the same reference numerals.

The reciprocating compressor of this embodiment is characterized in that the piston pin 12 is made of SKD61 steel, and the surface hardness (Vickers hardness) is set to Hv> 1000 by the nitriding treatment. It was done.

As described above, the bearing portion on the small end side has a swing motion (oscillating motion), and it is difficult to operate with fluid lubrication under severe conditions such as high compression ratio conditions, and it is difficult to operate under the boundary lubrication boundary region. You are driving. Therefore, in order to prevent abnormal wear of the bearing portion on the small end side, the proof stress UP of the bearing portion itself is necessary. As a means thereof, the hardness of the piston pin 12 is increased. As is clear from FIG. 8, by setting the hardness of the piston pin 12 to Hv> 1000, the wear amount of the bearing portion on the small end side can be greatly reduced. Therefore, here, the hardness of the piston pin 12 is set to Hv> 1000 to prevent abnormal wear. As a result, it is possible to prevent seizure and abnormal wear in the bearing portion on the small end side, and obtain a highly reliable reciprocating compressor.

Embodiment 3. FIG. 9 shows claims 1 and 2 of the present invention.
FIG. 4 is a partial cross-sectional view of a small-end side bearing tubular portion that is an essential part of the reciprocating compressor according to Nos. 2 and 3, in which the same parts as those of the first and second embodiments described above are designated by the same reference numerals. It is attached.

In FIG. 9, reference numeral 11 denotes a plurality of grooves formed on the inward surface load side of the bearing metal 10, and the maximum swing of the connecting rod 6A about the cylinder center axis of the small end bearing housing 6g composed of the small end side bearing cylindrical portion. It is provided at the same angular pitch as the angle θ, and both longitudinal ends thereof are opened, and the opening position of one is set to the maximum swing angle θ.
It is set in a multi-row spiral shape by shifting the same pitch as. That is, in the AA cross section of FIG.
One of the openings 11a is set such that the positions of adjacent ones are displaced in the circumferential direction at a swing angle θ pitch interval, and the openings 11c of the plurality of grooves 11 are also formed on the opposite side C-C cross section. The positions of adjacent ones are set to be shifted in the circumferential direction at a swing angle θ pitch interval. Further, each groove 11 is formed by twisting by the swing angle θ in the bearing rotation direction at the opening position on the cross section AA side and the opening position on the cross section CC side. Reference numeral 11b in FIG. 9 is provided on the bearing metal 10 to form a fifth oil passage, which is a circumferential groove 6f and a plurality of grooves 11b.
Communication hole, 12 is a piston pin made of SKD61 steel, surface hardness (Vickers hardness) by nitriding treatment
Is set to Hv> 1000. All other configurations are the same as those of the first embodiment described above.

As described above, in the reciprocating compressor of this embodiment, as in the first embodiment, the spiral groove 11 is formed on the inner surface of the bearing metal 10 on the load side and the small end bearing housing 6g. Connecting rod 6 centered on the cylinder center axis
Since a plurality of them are provided in the circumferential direction at the same angular pitch as the maximum swing angle θ of A, the swinging motion of the connecting rod 6A can continuously supply oil over the entire load side of the sliding surface of the piston pin 12. Therefore, the bearing portion (contact surface portion having no groove) always exists in the cylinder center axis direction of the bearing metal 10. Therefore, during the swing motion, the bearing surface is always present without being blocked, and a stable oil film is formed without interruption of hydraulic pressure. Therefore, the total hydraulic pressure is increased, the bearing load capacity is increased, and the bearing characteristics are improved.

Further, since the longitudinal ends of the multi-thread spiral groove 11 are open, the lubricating oil which is supplied into the bearing clearance and whose temperature is raised by the frictional heat due to sliding is immediately discharged to the outside of the bearing. , The temperature inside the bearing does not rise and is always cooled with lubricating oil. Furthermore, since the surface hardness of the piston pin 12 is set to Hv> 1000, abnormal wear is prevented. Therefore, even in a high compression ratio operation in which the piston pin 12 is difficult to move in the vertical direction or in an HFC refrigerant atmosphere with poor self-lubricating properties, a stable oil film and oil pressure can be obtained without oil shortage, and swing The frictional heat due to the movement can be always removed by the lubricating oil, and the temperature rise in the bearing can be prevented. As a result, seizure and abnormal wear in the small end bearing housing 6g can be prevented, and a highly reliable reciprocating compressor can be obtained.

Embodiment 4. FIG. 10 is a vertical cross-sectional view showing a small end side bearing tubular portion which is an essential part of a reciprocating compressor according to claim 4 of the present invention. In the figure, the same parts as those of the above-described first embodiment are not shown. The same reference numerals are attached.

In FIG. 10, reference numeral 13 is a piston, 14 is a piston pin, and 15 is a hexagon socket set screw, which is inserted into a hole 14a provided in the piston pin 14 and which has a piston 1
By fixing it to the female threaded portion 13a provided in 3, the piston pin 14 is fixed to the piston 13 (in particular, the rotation direction is fixed).
is doing. All other configurations are the same as those of the first embodiment described above.

In the reciprocating compressor of this embodiment, since the piston pin 14 is fixed to the piston 13, the bearing metal 1 in the bearing portion on the small end side during the swing motion.
The sliding position of 0 and the piston pin 14 can always be made constant. In other words, when the piston pin 14 is not fixed to the piston 13, the piston pin 14 and the piston 1
3. The positions of the piston pin 14 and the bearing metal 10 are not stable, and the sliding length of the bearing portion on the small end side due to the swing motion of the connecting rod 6A is between the piston 13 and the piston pin 14, and between the piston pin 14 and the bearing metal 10. The required sliding length between the piston pin 14 and the bearing metal 10 is reduced, the oil film and hydraulic pressure are reduced, and the sliding between the piston 13 and the piston pin 14, which should not occur originally, is performed. This causes abnormal wear. Therefore, by fixing the piston 13 and the piston pin 14 particularly in the rotational direction as in the present embodiment, the sliding length of the bearing portion on the small end side during the swing movement of the connecting rod 6A is always equal to that of the piston pin 14. It becomes equal to the sliding length formed by the bearing metal 10, and the maximum sliding length of the swing motion is transmitted to the piston pin 14. As a result, stable hydraulic pressure and oil film formation are possible, and a highly reliable bearing portion free from abnormal wear can be obtained.

Although the piston pin 14 and the piston 13 are fixed to each other with a hexagon socket set screw, the piston pin 14 and the piston 13 may be restricted from rotating relative to each other. For example, instead of screw fixing, other fixing methods such as fixing by press-fitting a pin or press-fitting the piston pin 14 into the piston 13 may be adopted. Even in such a case, the same action as that of the present embodiment is obtained. , The effect is obtained.

Embodiment 5. FIG. 11 shows claim 4 of the present invention.
5 is a vertical cross-sectional view showing a small-end side bearing tubular portion which is a main part of the reciprocating compressor according to No. 5, in which the same parts as those of the first and fourth embodiments described above are designated by the same reference numerals. There is.

In FIG. 11, 13 is a piston, 16 is a piston pin made of SKD61 steel, and the surface hardness (Vickers hardness) is set to Hv> 1000 by nitriding treatment. 15 is a hexagon socket set screw, and the piston pin 16
The piston pin 16 is fixed to the piston 13 (in particular, the rotation direction is fixed) by being inserted into the hole 16a provided in the piston 13 and being fixed to the female screw portion 13a provided in the piston 13.
The rest of the configuration is the same as that of the first embodiment described above.

Also in the reciprocating compressor of this embodiment, the groove formed on the inward surface load side of the bearing metal 10 is
A plurality of small-end bearing housings 6g each including a small-end side bearing cylinder are provided in the circumferential direction at the same angular pitch as the maximum swing angle θ of the connecting rod 6A around the cylinder center axis, and both longitudinal ends are open and The other opening position is shifted by the same pitch as the maximum swing angle .theta. Therefore, as in the case of the first embodiment described above, the swing motion of the connecting rod 6A allows continuous lubrication over the entire load side of the sliding surface of the piston pin 16, and during the swing motion, the oil can be replenished in the cylinder center axis direction. A stable oil film is formed without interruption of hydraulic pressure.

Further, the multi-spiral groove formed on the inward surface load side of the bearing metal 10 is open at both longitudinal ends, so that oil is fed into the bearing clearance, and the temperature rises due to frictional heat caused by sliding. The oil immediately flows out of the bearing, the temperature inside the bearing does not rise, and the oil is always cooled by the lubricating oil.
Furthermore, the surface hardness of the piston pin 16 is Hv> 1000.
Since it is set to, abnormal wear is prevented.

Further, since the piston pin 16 is fixed to the piston 13, the sliding position of the bearing metal 10 and the piston pin 16 in the bearing portion on the small end side can always be kept constant during the swing motion. Therefore, the piston pin 1
Even when high compression ratio operation in which 6 does not move vertically or in an HFC refrigerant atmosphere where self-lubrication is poor, a stable oil film and oil pressure can be obtained without oil shortage, and friction heat due to swing motion can be obtained. Can be always removed by the lubricating oil, and the temperature rise in the bearing can be prevented.

As described above, since the reciprocating compressor of this embodiment has both the functions of the third and fourth embodiments, seizure or abnormality in the small end side bearing tubular portion 6g. A reciprocating compressor that can surely prevent wear and has higher reliability can be obtained.

[0039]

As described above, according to the invention of claim 1, the housing of the small end side bearing tubular portion is provided with the circumferential groove communicating with the fourth oil passage, and the circumferential groove is formed. A fifth oil passage formed of the housing is provided, and the fifth oil passage is communicated with a plurality of grooves along the bearing longitudinal direction provided on the inner surface load side of the housing, and the plurality of grooves are It is set to be offset by the same angle pitch as the maximum swing angle θ of the connecting rod around the cylinder center axis of the small-end side bearing cylinder, and both longitudinal ends of the groove are opened, and one opening position is set to the other opening position. Since it is formed in a multi-screw shape with a pitch equal to or greater than the maximum swing angle θ, it does not run out of oil even during high compression ratio operation in which vertical movement of the piston pin is difficult to obtain, and during swing movement Oil film Balance could be reduced and the average oil pressure (oil film) could be increased. For this reason, it was possible to prevent burning and abnormal wear and improve reliability.

According to the invention of claim 2, claim 1
Since the surface hardness of the piston pin is set to Hv> 1000, oil will not run out even in high compression ratio operation where vertical movement of the piston pin is difficult to obtain, reducing oil film imbalance during swing motion. It was possible to increase the average oil pressure (oil film). For this reason, it was possible to prevent burning and abnormal wear and improve reliability.

According to the invention of claim 3, claim 1
Alternatively, since the piston and the piston pin according to claim 2 are fixed and the relative rotation between them is regulated, the sliding length of the swinging movement of the connecting rod is always formed by the piston pin and the bearing metal. It became equal to the sliding length of the cylinder, the maximum sliding length of the swing motion was transmitted to the piston pin, and stable hydraulic pressure and oil film formation became possible. Therefore, a highly reliable bearing without abnormal wear I got a part.

According to the invention of claim 4, a case having an oil sump at the bottom, a cylinder arranged in the case, a crankshaft rotatably supported in the case, and a cylinder. A piston that is slidably mounted, a piston pin that is inserted into and supported by the piston, and a small-end bearing cylinder and a crankshaft that pivotally support the piston pin at a predetermined swing angle. In the case of a connecting rod having a large-end-side bearing tubular portion that pivots, the surface hardness of the piston pin is set to Hv> 1000, so the bearing proof strength and limit can be increased, and reliability can be further improved. It was

According to the invention of claim 5, claim 4
Since the surface hardness of the piston pin is set to Hv> 1000, oil will not run out even in high compression ratio operation where vertical movement of the piston pin is difficult to obtain, reducing oil film imbalance during swing motion. It was possible to increase the average oil pressure (oil film). Furthermore, the sliding length of the connecting rod that makes a swing motion is always equal to the sliding length of the small end side bearing cylinder that is formed by the piston pin and bearing metal, and the maximum sliding length of the swing motion is transmitted to the piston pin. This enabled stable oil pressure and oil film formation. Therefore, a highly reliable bearing portion free from seizure or abnormal wear could be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of a reciprocating compressor according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a connecting rod of the reciprocating compressor according to the first embodiment in a state of being cut in a cylinder axis direction along a central axis.

FIG. 3 is an enlarged perspective view showing the connecting rod small end side bearing tubular portion of FIG. 2;

FIG. 4 is a partial cross-sectional view of a connecting rod small end side bearing tubular portion for explaining the shape of a groove formed in the bearing metal of the reciprocating compressor according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating a positional relationship between the piston pin and the connecting rod of the reciprocating compressor according to the first embodiment during operation.

FIG. 6 is an explanatory diagram showing an effect of the reciprocating compressor according to the first embodiment in comparison with a conventional example.

FIG. 7 is a vertical cross-sectional view showing a small-end side bearing tubular portion which is a main part of a reciprocating compressor according to a second embodiment of the present invention.

FIG. 8 is a graph showing the results of a compressor durability test under a high compression ratio condition with an HFC refrigerant, which was performed to confirm the effect of the reciprocating compressor according to the second embodiment.

FIG. 9 is a partial cross-sectional view of a small end side bearing tubular portion which is a main portion of a reciprocating compressor according to a third embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view showing a small end side bearing tubular portion which is a main part of a reciprocating compressor according to a fourth embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view showing a small-end side bearing tubular portion which is a main part of a reciprocating compressor according to a fifth embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view showing a main part of a conventional reciprocating compressor.

FIG. 13 is a perspective view graph showing a connecting rod of a conventional reciprocating compressor in a state of being cut in the cylinder axis direction along the central axis.

14 is an enlarged perspective view showing the flow of lubricating oil in the enlarged portion of the small-end side bearing tubular portion of the connecting rod in FIG. 13. FIG.

FIG. 15 is an explanatory diagram for explaining a positional relationship between a piston pin and a connecting rod of a conventional reciprocating compressor during operation.

[Explanation of symbols]

1 case, 1c first oil passage, 2 cylinder, 3
Crankshaft, 3a Second oil passage, 3b Third oil passage, 4,13 Pistons, 5, 12, 14, 16
Piston pin, 6A connecting rod, 6b large end side bearing cylinder part, 6c fourth oil passage, 6f circumferential groove, 6g small end bearing housing (small end side bearing cylinder part), 7 oil pump,
8 oil sump, 11 multiple grooves, 11a one opening, 11
c The other opening, 15 set screw.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadashi Kimura             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F-term (reference) 3H003 AA02 AB00 AC01 AD01 BD07                       BD10 CB02 CB06 CD04

Claims (5)

[Claims] 1. A case having an oil sump at the bottom, a cylinder arranged in the case, a crankshaft pivotally supported in the case, and slidably arranged in the cylinder. Piston, a piston pin inserted into and supported by the piston, a small-end-side bearing cylindrical portion that pivotally supports the piston pin at a predetermined swing angle, and a crankshaft that is pivotally supported. A connecting rod having a large-end side bearing tubular portion, an oil pump for pumping the lubricating oil in the oil sump, a first oil passage for communicating the oil sump with the oil pump, and an axial center portion of the crankshaft. A second oil passage that is provided and communicates with the discharge side of the oil pump; and a third oil passage that communicates with the second oil passage provided on the crankshaft and the large end bearing portion. A reciprocating compressor provided inside the connecting rod and having a fourth oil passage communicating with the large end side bearing portion and the small end side bearing portion, wherein the housing of the small end side bearing tubular portion is provided with An orbiting concave groove communicating with the fourth oil passage is provided, and a fifth oil passage formed by the orbiting concave groove and the housing is provided, and the fifth oil passage and the inner surface load side of the housing are provided. To communicate with a plurality of grooves along the longitudinal direction of the bearing, and the plurality of grooves,
It is set to be offset by the same angle pitch as the maximum swing angle θ of the connecting rod around the cylinder center axis of the small-end side bearing cylinder, and both longitudinal ends of the groove are opened, and one opening position is set to the other opening position. A reciprocating compressor characterized by being formed in a multi-row spiral shape with a pitch that is offset by at least the same pitch as the maximum swing angle θ. 2. The reciprocating compressor according to claim 1, wherein the surface hardness of the piston pin is Hv> 1000. 3. The reciprocating compressor according to claim 1, wherein the piston and the piston pin are fixed. 4. A case having an oil sump at the bottom, a cylinder arranged in the case, a crankshaft pivotally supported in the case, and slidably arranged in the cylinder. Piston, a piston pin inserted into and supported by the piston, a small-end-side bearing cylindrical portion that pivotally supports the piston pin at a predetermined swing angle, and a crankshaft that is pivotally supported. A reciprocating compressor having a connecting rod provided with a large-end side bearing tubular portion, wherein the surface hardness of the piston pin is set to Hv> 1000. 5. The reciprocating compressor according to claim 4, wherein the piston and the piston pin are fixed.