JPH07259738A - Hermetic type compressor - Google Patents

Abstract

PURPOSE:To provide a high-reliable closed type compressor which is constituted to prevent wear of the connecting rod of the piston pin of a closed compressor. CONSTITUTION:A semiperipheral oil feed groove 24 formed in the peripheral direction of a piston rod 23 intercommunicating a feed oil hole 10 and a discharge oil hole 11 is formed in a range to a portion right before a position wherein a relative speed between a connecting rod 7 and a piston pin 23 during a time starting from the suction stroke of a piston 2 to a compression stroke is reduced to zero. This constitution ensures an amount of oil sufficiently fed to a slide part between the piston pin and the small end hole 8 of the connecting rod.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating hermetic compressor used for a refrigerating machine or the like.

[0002]

2. Description of the Related Art A hermetic compressor used in a refrigerating machine or the like has a highly reliable one because an electric compression element is housed in a hermetic container and maintenance and repair cannot be performed in the hermetic container. It is rare. Above all, the sliding portion between the piston pin of the reciprocating compressor and the small end hole of the connecting rod receives a large surface pressure due to compression, and is in a severe sliding state. Therefore, there has been conventionally devised a method of preventing the lubrication failure of the sliding portion between the piston pin and the small end hole of the connecting rod to improve the reliability. Regarding the method of refueling the connecting rod small end hole, for example, Japanese Utility Model Publication No. 47-16836, and for the circumferential groove provided in the sliding portion between the connecting rod small end hole and the piston pin, see, for example, Japanese Patent Application Laid-Open No. 275072. There is a hermetic electric compressor as shown in.

An example of the above-mentioned conventional hermetic electric compressor will be described below with reference to the drawings.

FIG. 7 is a sectional view showing a conventional hermetic electric compressor. In FIG. 7, reference numeral 1 is a cylinder in which a piston 2 reciprocates. Reference numeral 3 is a bearing that supports the crankshaft 4. The piston 2 has a hollow portion 5 and a through hole 6 in a direction orthogonal to the axial direction.

Reference numeral 7 is a connecting rod having a small end hole 8 at one end and a large end hole 9 at the other end. Reference numeral 10 denotes both ends on a plane that passes through the connecting rod 7, connects the small end hole 8 and the large end hole 9 and passes through the axis of the small end hole 8 and the axis of the large end hole 9. Is an oil supply hole that opens, and 11 is an oil discharge hole that connects the small end hole 8 and the outside of the connecting rod 7. Reference numeral 12 is an eccentric portion formed on the crankshaft 4.

Reference numeral 13 is a shaft oil supply hole formed in the crankshaft 4, and 14 is an eccentric part oil supply hole which is in cross communication with the shaft oil supply hole 13, and is opened in an oil sump 15 provided on the surface of the eccentric part 12. is doing.

Reference numeral 16 is an oil supply pipe fixed to the crank eccentric portion 12, and communicates with the shaft oil supply hole 13.
Oil is stored in the bottom of the closed container (not shown).
Is soaked in. The small end hole 8 of the connecting rod 7 is inserted into the hollow portion 5 of the piston 2, and the through hole 6 and the small end hole 8 are formed.
The piston 2 is connected to the crankshaft 4 by inserting the piston pin 18 into and the eccentric portion 12 into the large end hole 9. Reference numeral 19 is a circumferential groove provided on the surface of the piston pin 18 in the circumferential direction, and 20 is a locking pin for fixing the piston pin 18 to the piston 2.

The operation of the hermetic compressor constructed as described above will be described below. As the crankshaft rotates, oil pressure is generated in the oil 17 in the oil supply pipe 16, and the oil 17 rises in the oil supply pipe 16 and the shaft oil supply hole 13. Part of the raised oil 17 is the eccentric part oil supply hole 14
Through the oil reservoir 15 to lubricate the sliding portion between the large end hole 9 and the eccentric portion 12. In addition, the oil sump 15
A part of the oil of the above flows to the small end hole 8 through the oil supply hole 10, lubricates the sliding portion between the piston pin 18 and the small end hole 8, passes through the circumferential groove 19, and further passes through the oil drain hole 11. Piston 2
Flows out into the hollow portion 5 of.

8 (a) to 8 (d) show an oil supply hole 10 and an eccentric portion 12 in the connecting rod 7 in the AA cross section shown in FIG.
FIG. 3 is a process diagram showing a relationship between an internal crank oil supply hole 14 and an oil sump 15. As is clear from the relationship between the oil supply hole 10 of the connecting rod 7 and the crank oil supply hole 14 of the eccentric portion 12 and the oil sump 15 during one rotation of the crankshaft 4 in FIG. 7, the oil 17 is constantly kept in the crank oil supply hole 14 and the oil sump 15 Can flow into the oil supply hole 10 of the connecting rod 7 only from the suction stroke of FIG. 8C to FIG. 8D, that is, from the top dead center to the bottom dead center of the piston 2. With this structure, the eccentric portion 12 receives a large load from the large end portion 9 of the connecting rod 7 during the compression stroke.
Since the load is applied to the portion where the second oil reservoir 15 does not exist, oil film pressure is likely to be generated in the sliding portion between the eccentric portion 12 and the large end hole 9, and abrasion due to metal contact can be made difficult.

In addition to the above-described conventional method for supplying oil to the small end hole 8 of the connecting rod 7 of the hermetic compressor, the small end hole 8 is provided with a V groove, or the small end hole 8 and the piston pin are supplied with oil. There are some things that have no groove for it.

FIG. 9 is a sectional view of a piston device in which a V-groove is provided in a small end hole 8 of a connecting rod 7 of a conventional hermetic electric compressor.

In FIG. 9, reference numeral 21 denotes a piston pin having no groove for oil supply on its sliding surface with the small end hole 8. Reference numeral 22 denotes a V groove provided on the sliding surface of the small end hole 8 with respect to the piston pin 22 in the axial direction of the small end hole 8 and at a position orthogonal to the oil supply hole 10.

The operation of the hermetic compressor constructed as described above will be described below. The oil 17 flowing to the small end hole 8 through the oil supply hole 10 of the connecting rod 7 is
It flows out into the hollow portion 5 of the piston 2 through 2 and lubricates the sliding portion between the piston pin 21 and the small end hole 8. Therefore,
The same effect as that obtained by providing the piston pin 17 with the circumferential groove 19 can be obtained.

FIG. 10 is a sectional view of a piston device of the conventional hermetic electric compressor in which the small end hole 8 of the connecting rod 7 and the piston pin 21 have no groove for oil supply.

In FIG. 10, reference numeral 21 denotes a piston pin in which a groove for oil supply is not provided on the sliding surface with the small end hole 8, and the small end hole 8 has a groove for oil supply as described above. Is not provided.

The operation of the hermetic compressor constructed as above will be described below. The oil 17 flowing to the small end hole 8 through the oil supply hole 10 of the connecting rod 7 lubricates the sliding portion between the piston pin 21 and the small end hole 8. With this structure, when a load is received by the small end hole 8 during the compression stroke, compared with a structure in which the circumferential groove 19 or the V groove 22 is provided in the sliding portion between the small end hole 8 and the piston pin 21, Since the oil 17 does not flow out from the groove, oil film pressure is likely to occur.

[0017]

However, among the above-mentioned conventional configurations, those in which the piston pin is provided with the circumferential groove and those in which the small end hole is provided with the V groove are the piston pin and the connecting rod during the compression stroke. When it becomes difficult to form an oil film on the sliding part due to the relative speed of 0, the sliding surface always has the circumferential groove of the piston pin or the V groove of the small end hole. It was difficult to form the oil film, and there was a drawback that the sliding part was worn due to metal contact.

Further, in the above-mentioned conventional structure, the small end hole and the piston pin having no groove for oil supply have the following drawbacks when foreign matter is caught in the sliding portion between the piston pin and the small end hole. Since there is no groove for refueling, it is difficult for foreign matter to be discharged, and because the sliding part wears out due to the oil film running out due to abnormal heat generation in the sliding part and scratches on the sliding surface, there is no groove. There are drawbacks that the amount of oil supply is reduced, the cooling effect of the oil is reduced, and poor lubrication such as a decrease in oil viscosity is likely to occur due to a rise in the temperature of the sliding portion.

The present invention solves the conventional problems by facilitating the formation of an oil film at the sliding portion between the piston pin and the small end hole of the connecting rod and ensuring a sufficient amount of oil supply to the sliding portion. Therefore, it is an object of the present invention to prevent the sliding portion from being worn and to provide a highly reliable hermetic compressor.

[0020]

In order to achieve this object, a hermetic compressor of the present invention comprises a piston, a connecting rod having a small end hole at one end and a large end hole at the other end, and a small rod passing through the connecting rod. An oil supply hole that communicates the end hole and the large end hole, and has both ends open on a plane that passes through the axis of the small end hole and the axis of the large end hole,
An oil drain hole that connects the small end hole sliding surface to the connecting rod outer surface,
A piston pin slidably housed in a small end hole and fixed to the piston, and an oil supply hole from the piston suction process to immediately before the position where the relative speed of the connecting rod and piston pin during the compression stroke becomes zero. It is composed of a semicircular oil supply groove provided in the circumferential direction of the piston pin communicating with the oil drain hole.

Further, when the relative speed between the connecting rod and the piston pin during the compression stroke becomes zero, the semicircular oil supply groove is reciprocated so as to close the cross section of the groove, and the semicircular oil supply groove is closed. The vane is provided in the small end hole of the connecting rod, which is close to the end surface on the oil supply hole side.

Further, the bypass groove in the semicircular oil supply groove is provided at a position where the oil supply hole and the oil discharge hole are communicated with each other only during the oil supply in the suction stroke via the vane.

Further, a semicircular lubrication provided in the circumferential direction on the outer surface of the piston pin, one end of which communicates with the end face on the lubrication hole side of the semicircular lubrication groove, and the other end of which does not communicate with anything. It is provided with at least one oil groove having a cross-sectional area smaller than the cross-sectional area of the groove.

[0024]

In the hermetic compressor of the present invention, when the relative speed between the piston pin and the connecting rod becomes zero during the compression stroke and the formation of the oil film at the sliding portion becomes the most difficult, the piston pin has a semi-circular shape. Since the load is applied to the portion where there is no circumferential oil supply groove, it is easy to form an oil film on the sliding portion, and it is possible to prevent abrasion of the sliding portion. Also, during other compression strokes, part of the semicircular lubrication groove matches the sliding surface part that receives the load. Since it can be discharged, it is possible to prevent abnormal heat generation in the sliding portion and scratches on the sliding surface due to foreign matter being caught. Also, during the suction stroke, the oil supply hole of the connecting rod and the semicircular oil supply groove of the piston pin are aligned and communicate with each other, so it is possible to perform oil supply to the small end hole as with the conventional circular groove specification. it can. Therefore, the cooling effect of the oil can be obtained, and the lubrication failure such as the decrease of the viscosity of the oil due to the temperature rise of the sliding portion can be prevented and the sliding portion can be less likely to be worn.

Further, when the relative speed between the connecting rod and the piston pin becomes zero during the compression stroke, the vane provided in the small end hole of the connecting rod approaches the end face on the oil supply hole side in the semicircular oil supply groove. As a result, the oil in the semicircular oil supply groove can be forcibly sent to the sliding surface. Therefore, the oil film can be easily formed on the sliding portion between the small end hole of the connecting rod and the piston pin, and the sliding portion of the small end hole and the piston pin can be less likely to be worn.

Furthermore, the oil in the semicircular oil supply groove, which was blocked by the vanes during the compression stroke and stopped flowing, is circulated by the bypass groove so that the oil supply hole and the oil discharge hole are communicated with each other only during the oil supply in the suction stroke. Let the oil flow. Therefore, it is possible to prevent the oil in the oil supply hole and the oil in the oil supply hole part, which receives the large load of the piston pin and becomes the sliding surface, from flowing out from the sliding surface except when the oil is supplied in the suction stroke, so that the oil film is unlikely to run out. it can. In addition, since a stable amount of oil can be supplied to the small end hole during refueling during the suction stroke, the cooling effect of the oil can be obtained, and it is possible to prevent poor lubrication such as a decrease in oil viscosity due to a rise in the temperature of the sliding part. The sliding portion between the hole and the piston pin can be made less likely to wear.

Furthermore, the vane provided on the piston pin reduces the relative velocity between the piston pin and the connecting rod during the compression stroke to 0, and the oil forcedly fed to the sliding portion when the oil film becomes liable to run out, Oil can be exuded from the oil groove to the sliding surface. Therefore,
It is possible to promote the generation of an oil film on the sliding surface and make the sliding portion between the small end hole and the piston pin less likely to wear.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the hermetic compressor of the present invention will be described below with reference to the drawings. It should be noted that the same components as those of the related art are denoted by the same reference numerals and detailed description thereof will be omitted.

FIG. 1 shows a first embodiment of the hermetic compressor of the present invention, and FIG. 2 is a process showing the relationship between the oil supply hole, the crank oil supply hole, and the oil sump in the AA cross section shown in FIG. There is a figure.

In FIGS. 1 and 2, reference numeral 23 denotes a piston pin, and 24 denotes an oil supply hole from a suction process of the piston 2 to a position immediately before a position where the relative speed between the connecting rod 7 and the piston pin 23 during the compression stroke becomes zero. It is a semicircular oil supply groove provided in the circumferential direction of the piston pin 23 that communicates the oil discharge hole 11 with the oil discharge hole 11.

The operation of the hermetic compressor constructed as above will be described below. In general, the position where the oil film is most likely to run out at the sliding portion between the piston pin and the small end hole during one rotation of the crank is the relative speed between the piston pin 23 and the connecting rod 7 during the compression stroke shown in FIG. 2B. Is a position at which 0 becomes 0. At that time, the opening portion of the oil supply hole 10 to the small end hole 8 makes contact with the piston pin 23 and the small end hole 8 of the connecting rod 7 at a portion of the piston pin 23 where there is no semicircular oil supply groove 24, and that portion is made. It becomes a sliding surface. Therefore, compared with the conventional piston pin 18 having the circumferential groove,
It is possible to facilitate the formation of an oil film on the sliding portion and make it difficult for the sliding portion to wear.

During the other compression strokes, a part of the semicircular oil supply groove 24 is aligned with the sliding surface portion receiving the load, so that foreign matter on the sliding surface receiving the load is a semicircle. Since the oil can be discharged from the circumferential oil supply groove 24, it is possible to prevent abnormal heat generation in the sliding portion and scratches on the sliding surface due to foreign matter being caught.

2 (c) to 2 (d), the oil supply hole 10 and the oil discharge hole 11 of the connecting rod 7 communicate with the semicircular oil supply groove 24 of the piston pin 23 so as to communicate with each other. It is possible to supply oil to the small end hole 8 as in the case of the conventional circumferential groove specification. Therefore, the cooling effect of the oil 17 can be obtained, and the lubrication failure such as the viscosity decrease of the oil 17 due to the temperature rise of the sliding portion can be prevented, and the sliding portion can be less likely to wear.

As described above, the hermetic compressor of this embodiment is
The relative speed between the piston pin 23 and the connecting rod 7 and the piston pin 23 during the compression stroke from the suction process of the piston 2 is 0.
Until just before the position, the piston pin 23 is formed with a semicircular oil supply groove 24 provided in the circumferential direction of the piston pin 23 that communicates the oil supply hole 10 with the oil discharge hole 11. When the relative speed between the piston pin 23 and the connecting rod 7 becomes zero and the formation of the oil film at the sliding portion becomes the most difficult, the piston pin 23 receives the load at the portion without the semicircular oil supply groove 24, so that the sliding It is easy to form an oil film on the moving part, and it is possible to prevent abrasion of the sliding part.

During the other compression strokes, a part of the semicircular oil supply groove 24 coincides with the sliding surface portion receiving the load, so that foreign matter on the sliding surface receiving the load has a semicircular circumference. Since the oil can be discharged from the oil supply groove 24, the abnormal heat generation of the sliding portion and the scratching of the sliding surface due to the foreign matter being caught can be prevented.

Further, since the oil supply hole 10 of the connecting rod 7 and the semicircular oil supply groove 24 of the piston pin 23 communicate with each other during the suction stroke, the small end hole is provided as in the conventional circular groove specification. 8 can be refueled. Therefore, the cooling effect of the oil 17 can be obtained, and the lubrication failure such as the viscosity decrease of the oil 17 due to the temperature rise of the sliding portion can be prevented, and the sliding portion can be less likely to wear.

In this embodiment, the semicircular oil supply groove 24 is used. However, the semicircular oil supply groove 24 is located at a position where the relative speed between the piston pin 23 and the connecting rod 7 in the compression stroke is zero. It may be located at any position on the circumference as long as the circumferential oil supply groove 24 and the oil supply hole 10 do not communicate with each other and the oil supply hole 10 and the oil discharge hole 11 communicate with each other during the suction stroke.

Next, a second embodiment of the hermetic compressor of the present invention will be described with reference to the drawings. The same components as those in the conventional example and the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 3 shows a second embodiment of the hermetic compressor of the present invention. In FIG. 3, reference numeral 25 reciprocates in a semicircular oil supply groove 24 so as to close the cross section of the groove, and when the relative speed between the connecting rod 7 and the piston pin 23 during the compression stroke becomes 0, the semicircular shape is formed. This is a vane provided in the small end hole 8 of the connecting rod 7 close to the end surface of the oil supply groove 24 on the oil supply hole 10 side.

The operation of the hermetic compressor constructed as above will be described below. In the compression stroke, when the relative speed between the connecting rod 7 and the piston pin 23 shown in FIG.
4, the oil 17 in the semicircular oil supply groove 24 is compressed by the end surface of the semicircular oil supply groove 24 on the oil supply hole 10 side, and the oil is absorbed in the sliding surface. The oil 17 is forcibly sent. Therefore, the small end hole 8 of the connecting rod 7
Thus, an oil film can be easily formed on the sliding portion of the piston pin 23, and the small end hole 8 and the sliding portion of the piston pin 23 can be less likely to wear.

As described above, the hermetic compressor of this embodiment is
It reciprocates in a semicircular oil supply groove 24 so as to close the cross section of the groove, and the connecting rod 7 and piston pin 23 during the compression stroke.
Of the connecting rod 7 in the small end hole 8 of the connecting rod 7 that is close to the end face of the connecting groove 24 on the side of the filling hole 10 when the relative speed of the connecting rod 7 becomes zero. It becomes easier to form an oil film on the sliding portion between the small end hole 8 and the piston pin 23, and the sliding portion between the small end hole 8 and the piston pin 23 can be made less likely to wear.

Next, a third embodiment of the hermetic compressor of the present invention will be described with reference to the drawings. Incidentally, the conventional example,
The same components as those in the first and second embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 4 shows a third embodiment of the hermetic compressor of the present invention. In FIG. 4, reference numeral 26 denotes the oil supply hole 10 and the oil discharge hole 11 through the vane only during the oil supply in the suction stroke.
Is a detour groove in a semicircular oil supply groove 24 provided at a position communicating with each other.

The operation of the hermetic compressor constructed as above will be described below. In addition to the effects of the second embodiment, the hermetic compressor configured as described above has
During the compression strokes (a) and (b), the flow of the oil 17 is blocked by the vane 26 so that the semicircular oil supply groove 24 is not blocked. The semicircular oil supply groove 24 closed by the vane 25 allows the oil supply hole 10 and the oil discharge hole 11 to communicate with each other by the bypass groove 26 only at the time of oil supply in the suction stroke shown in FIGS. 4C to 4E. The oil 17 can be flowed.

Therefore, it is possible to prevent the oil 17 in the oil supply hole 10 and in the oil supply hole 10 portion, which receives a large load of the piston pin 23 and serves as a sliding surface, from flowing out from the sliding surface except when the oil is supplied in the suction stroke. Because it can be done, it is possible to prevent the oil film from running out. In addition, since a stable amount of oil can be supplied to the small end hole 8 during the refueling in the suction stroke, the cooling effect of the oil 17 can be obtained, and the poor lubrication such as the viscosity decrease of the oil 17 due to the temperature rise of the sliding portion can be prevented. , Small end hole 8 and piston pin 2
It is possible to make the sliding portion of 3 less likely to wear.

As described above, the hermetic compressor of this embodiment is
Since the bypass groove 26 is provided in the semicircular oil supply groove 24 provided at the position where the oil supply hole 10 and the oil discharge hole 11 communicate with each other only during the oil supply in the intake stroke via the vane, Except when refueling, the inside of the refueling hole 10 and the piston pin 23
Since it is possible to prevent the oil 17 in the portion of the oil supply hole 10 which becomes a sliding surface to receive a large amount of the oil from flowing out from the sliding surface, it is possible to prevent the oil film from running out.

In addition, since a stable amount of oil can be supplied to the small end hole 8 at the time of refueling during the suction stroke, the cooling effect of the oil 17 can be obtained, and the oil 17 due to the temperature rise of the sliding portion can be obtained.
It is possible to prevent poor lubrication such as a decrease in viscosity, and to make the sliding portion between the small end hole 8 and the piston pin 23 less likely to wear.

Next, a fourth embodiment of the hermetic compressor of the present invention will be described with reference to the drawings. Incidentally, the conventional example,
The same components as those of the first, second and third embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 5 shows a fourth embodiment of the hermetic compressor of the present invention, and FIG. 6 is a sectional view taken along line BB of FIG.

In FIGS. 5 and 6, the reference numeral 27 indicates a circumferential direction on the outer surface of the piston pin 23, one end of which communicates with the end surface of the semicircular oil supply groove 24 on the oil supply hole 10 side and the other end of which does not communicate with anything. It is at least one oil groove having a cross-sectional area smaller than the cross-sectional area of the semicircular oil supply groove 24 provided in the.

The operation of the hermetic compressor constructed as described above will be described below. In addition to the effects of the third embodiment, the hermetic compressor configured as described above has a semicircular refueling at a position where the relative speed of the connecting rod 7 and the piston pin 23 during the compression stroke becomes zero. Oil 17 in the groove 24
Is brought closer to the oil supply hole 10 side of the semicircular oil supply groove 24 by the vane 25, and is further pushed into the oil groove 27 communicating with the semicircular oil supply groove 24, and exudes to the sliding surface. .

Therefore, the relative speed of the connecting rod 7 and the piston pin 23 during the compression stroke becomes 0, and the oil 17 is directly applied to the small end hole 8 of the connecting rod 7 and the sliding portion of the piston pin 23 where oil film breakage is likely to occur. The oil 17 is forcedly fed and the oil 17 exudes from the oil groove 27 to the sliding surface, thereby promoting the generation of an oil film on the sliding surface and making the sliding portions of the small end hole 8 and the piston pin 23 less likely to wear. be able to.

As described above, the hermetic compressor of this embodiment is
A semicircular oil supply groove 24 provided in the circumferential direction on the outer surface of the piston pin 23 having one end communicating with the end surface on the oil supply hole 10 side of the semicircular oil supply groove 24 and the other end not communicating with anywhere. Since it is composed of at least one oil groove 27 having a cross-sectional area smaller than the cross-sectional area of the connecting rod 7, the relative speed between the connecting rod 7 and the piston pin 23 during the compression stroke becomes zero, and the small end hole 8 of the connecting rod 7 and the piston The oil 17 is forcibly sent directly to the portion of the sliding portion of the pin 23 where the oil film is likely to run out, and the oil 17 exudes from the oil groove 27 to the sliding surface to promote the generation of the oil film on the sliding surface. The sliding portions of the small end hole 8 and the piston pin 23 can be made less likely to wear.

[0054]

As described above, according to the present invention, the piston pin and the oil supply hole and the oil discharge hole are provided from the intake process of the piston to the position immediately before the position where the relative speed between the connecting rod and the piston pin during the compression stroke becomes zero. Since it is composed of a semicircular oil supply groove provided in the circumferential direction of the piston pin that communicates with the piston pin, the relative speed of the piston pin and connecting rod during the compression stroke becomes zero, and the formation of an oil film on the sliding part is reduced. When it becomes difficult, the piston pin receives a load at a portion having no semicircular oil supply groove, so that an oil film can be easily formed on the sliding portion and abrasion of the sliding portion can be suppressed. In addition, during other compression strokes, part of the semicircular lubrication groove matches the sliding surface part that receives the load, so foreign matter on the sliding surface that receives the load has a semicircular lubrication groove. Since it can be discharged from the inside, it is possible to prevent abnormal heat generation in the sliding portion and scratches on the sliding surface due to foreign matter being caught. Also, during the suction stroke, the oil supply hole of the connecting rod and the semicircular oil supply groove of the piston pin are aligned and communicate with each other, so it is possible to perform oil supply to the small end hole as with the conventional circular groove specification. it can. Therefore, the cooling effect of the oil can be obtained, and the lubrication failure such as the decrease of the viscosity of the oil due to the temperature rise of the sliding portion can be prevented and the sliding portion can be less likely to be worn.

Further, when the reciprocating motion is performed in the semicircular oil supply groove so as to close the cross section of the groove, and the relative speed of the connecting rod and the piston pin during the compression stroke becomes zero, the oil flow of the semicircular oil supply groove is reduced. As it consists of a vane provided in the small end hole of the connecting rod close to the end face on the oil supply hole side, it is easy to form an oil film on the small end hole of the connecting rod and the sliding part of the piston pin. Also, the sliding portion of the piston pin can be made less likely to wear.

Further, since it is constituted by the bypass groove in the semicircular oil supply groove provided at the position where the oil supply hole and the oil discharge hole communicate with each other only during the oil supply in the intake stroke via the vane, the intake stroke It is possible to prevent the oil in the oil supply hole and the oil in the oil supply hole portion, which serves as a sliding surface, which receives a large load of the piston pin from flowing out from the sliding surface except when the oil is being refilled, so that the oil film is less likely to run out. In addition, since a stable amount of oil can be supplied to the small end hole during refueling during the suction stroke, the cooling effect of the oil can be obtained, and it is possible to prevent poor lubrication such as a decrease in oil viscosity due to a rise in the temperature of the sliding part. The sliding portion between the hole and the piston pin can be made less likely to wear.

Further, a semicircular lubrication is provided on the outer surface of the piston pin, which has one end communicating with the end face of the semicircular lubrication groove on the lubrication hole side and the other end not communicating with anything. Since it is composed of at least one oil groove having a cross-sectional area smaller than the cross-sectional area of the groove, the relative speed between the connecting rod and the piston pin during the compression stroke becomes 0, and the small end hole of the connecting rod and the piston pin slide. Oil is forcedly sent directly to the part where oil film breakage easily occurs, and the oil leaks from the oil groove to the sliding surface, promoting the generation of an oil film on the sliding surface, and It is possible to make the sliding portion less likely to wear.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a piston device of a hermetic compressor showing a first embodiment of the present invention.

2 (a) is a sectional view showing a piston bottom dead center state showing the relationship between an oil supply hole, a crank oil supply hole and an oil sump in the AA cross section shown in FIG. 1, and FIG. 2 (b) is a connecting rod of the same compression process. Sectional view showing a state where the relative speed of the piston pin is 0. (c) is a sectional view showing the suction process. (D) is a sectional view showing a state where the relative speed of the connecting rod and the piston pin is 0 in the suction process. e) is a sectional view showing a state in which the inhalation process is further advanced.

FIG. 3A is a cross-sectional view showing a bottom dead center state of a piston of a hermetic compressor according to a second embodiment, and FIG. 3B is a state in which a relative speed between a connecting rod and a piston pin in the compression process becomes zero. (C) is a sectional view showing the same suction process (d) is a sectional view showing a state where the relative speed between the connecting rod and the piston pin in the same suction process is 0 (e) is the same suction process Sectional view showing the state

FIG. 4A is a sectional view showing a bottom dead center state of a piston of a hermetic compressor according to a third embodiment. FIG. 4B is a state in which a relative speed between a connecting rod and a piston pin in the compression process becomes zero. (C) is a sectional view showing the same suction process (d) is a sectional view showing a state where the relative speed between the connecting rod and the piston pin in the same suction process is 0 (e) is the same suction process Sectional view showing the state

FIG. 5 is a longitudinal sectional view of a piston device of a hermetic compressor showing a fourth embodiment of the present invention.

6 is a cross-sectional view of the main part of the BB cross section shown in FIG.

FIG. 7 is a vertical sectional view of a piston device of a conventional hermetic compressor.

8 (a) is a sectional view showing a piston bottom dead center state showing the relationship between an oil supply hole, a crank oil supply hole, and an oil sump in the CC cross section shown in FIG. 6, and FIG. 8 (b) is a connecting rod in the same compression process. Sectional view showing a state in which the relative speed of the piston pin becomes 0. (c) is a sectional view showing the suction process. (D) is a sectional view showing the state where the suction process is further advanced.

FIG. 9 is a sectional view of another piston device of the conventional hermetic compressor.

FIG. 10 is a sectional view of another piston device of the conventional hermetic compressor.

[Explanation of symbols]

 2 piston 7 connecting rod 8 small end hole 9 large end hole 10 oil supply hole 11 oil discharge hole 23 piston pin 24 semicircular oil supply groove 25 vane 26 detour groove 27 oil groove

Claims (4)

[Claims] 1. A piston, a connecting rod having a small end hole at one end and a large end hole at the other end, a small end hole communicating with the large end hole through the connecting rod, and the small end hole. To the small end hole, an oil supply hole having both ends open on a plane passing through the shaft center of the large end hole and the shaft end of the large end hole, an oil drain hole communicating the small end hole sliding surface with the connecting rod outer surface, and the small end hole. It is slidably stored,
Further, the piston pin fixed to the piston is communicated with the oil supply hole and the oil discharge hole from a suction process of the piston to a position immediately before a position where the relative speed of the connecting rod and the piston pin at the time of a compression stroke becomes zero. A hermetic compressor comprising a semicircular oil supply groove provided in the circumferential direction of the piston pin. 2. A semi-circular oil supply groove projecting in a small end hole of the connecting rod so as to close the groove cross section, and the relative speed between the connecting rod and the piston pin during a compression stroke becomes zero. The hermetic compressor according to claim 1, further comprising a vane that is adjacent to an end surface of the circumferential oil supply groove on the oil supply hole side. 3. A crankshaft, an oil sump provided on a surface of an eccentric part of the crankshaft, and a position where the oil supply hole and the oil discharge hole are communicated with each other only while the oil sump and the oil supply hole are communicated with each other. The hermetic compressor according to claim 2, further comprising a bypass groove provided in the circumferential oil supply groove. 4. The semicircular circumferential shape provided on the outer surface of the piston pin, one end of which communicates with the end surface of the semicircular lubrication groove on the side of the lubrication hole and the other end of which does not communicate with anywhere. The hermetic compressor according to claim 3, further comprising at least one oil groove having a cross-sectional area smaller than a cross-sectional area of the oil supply groove.