Rotary compressor

In a rotary compressor, a protruding portion which protrudes downward from a bottom end of a rotation shaft and in which an outer diameter is smaller than an outer diameter of a sub-bearing unit is formed on the sub-bearing unit which is provided on a lower end plate, a step portion is formed between the protruding portion and the sub-bearing unit, and a center hole of a lower end plate cover is caused to mate with the protruding portion and is caused to come into close contact with the step portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priorities from Japanese Patent Application No. 2015-249118 filed on Dec. 21, 2015; the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to a rotary compressor (hereinafter, also referred to simply as a “compressor”) which is used in an air conditioner, a refrigerating machine, or the like.

BACKGROUND

For example, JP-A-2012-202237 describes a rotary compressor including a compressing unit disposed on the bottom portion of a compressor housing, compresses a refrigerant gas, and discharges the compressed refrigerant gas into the compressor housing via an upper muffler cover and a lower muffler cover (upper end plate cover, and a lower end plate cover); a motor disposed on the top portion of the compressor housing and drives the compressing unit via a rotation shaft; a lubricant oil stored on a bottom of the compressor housing; and a spiral-shaped pump impeller (oil feeding impeller) inserted (press-fitted) into a shaft hole (oil feeding vertical hole) of the bottom portion of the rotation shaft, and sucks up the lubricant oil from an inlet of the lower muffler cover into the shaft hole through the rotation of the rotation shaft to feed the lubricant oil to the compressing unit. In the rotary compressor, the inlet of the lower muffler cover is a cylindrical hole which protrudes downward.

However, the rotary compressor described in JP-A-2012-202237 performs the sealing of a lower muffler cover chamber (lower end plate cover chamber) by causing the lower end surface of a sub-bearing unit of a lower end plate to come into contact with the lower muffler cover (lower end plate cover). Therefore, there is a problem in that, in a case in which the sealing is insufficient, the refrigerant gas inside the lower muffler cover chamber leaks, flows into the shaft hole of the bottom portion of the rotation shaft, and mixes with the lubricant oil which is sucked up into the shaft hole, resulting in a negative influence on the lubrication of the compressing unit.

SUMMARY

An object of the present invention is to obtain a rotary compressor in which a refrigerant gas does not easily flow into a shaft hole (oil feeding vertical hole) of the bottom portion of a rotation shaft, even if the refrigerant gas inside a lower muffler cover chamber (lower end plate cover chamber) leaks.

The present invention is a rotary compressor which includes a sealed vertically-placed cylindrical compressor housing in which a discharge pipe which discharges a refrigerant is provided on a top portion and an upper inlet pipe and a lower inlet pipe which suck in the refrigerant are provided on bottom portions of side surfaces; an accumulator which is fixed to a side portion of the compressor housing and is connected to the upper inlet pipe and the lower inlet pipe; a motor which is disposed inside the compressor housing; and a compressing unit which is disposed beneath the motor inside the compressor housing, is driven by the motor, sucks in the refrigerant from the accumulator via the upper inlet pipe and the lower inlet pipe, compresses the refrigerant, and discharges the refrigerant from the discharge pipe, in which the compressing unit includes an upper cylinder and a lower cylinder which are formed in ring shapes, an upper end plate which blocks a top side of the upper cylinder and a lower end plate which blocks a bottom side of the lower cylinder, an intermediate partition plate which is disposed between the upper cylinder and the lower cylinder and blocks a bottom side of the upper cylinder and a top side of the lower cylinder, a rotation shaft which includes, in an inner portion thereof, an oil feeding vertical hole into which an oil feeding impeller is press-fitted and an oil feeding horizontal hole which communicates with the oil feeding vertical hole, whose main shaft unit is supported by a main bearing unit provided on the upper end plate, whose sub-shaft unit is supported by a sub-bearing unit provided on the lower end plate, and which is driven by the motor, an upper eccentric portion and a lower eccentric portion which are provided on the rotation shaft with a mutual phase difference of 180°, an upper piston which mates with the upper eccentric portion, revolves along an inner circumferential surface of the upper cylinder, and forms an upper cylinder chamber inside the upper cylinder, a lower piston which mates with the lower eccentric portion, revolves along an inner circumferential surface of the lower cylinder, and forms a lower cylinder chamber inside the lower cylinder, an upper vane which protrudes into the upper cylinder chamber from an upper vane groove which is provided in the upper cylinder, comes into contact with the upper piston, and partitions the upper cylinder chamber into an upper inlet chamber and an upper compression chamber, a lower vane which protrudes into the lower cylinder chamber from a lower vane groove which is provided in the lower cylinder, comes into contact with the lower piston, and partitions the lower cylinder chamber into a lower inlet chamber and a lower compression chamber, an upper end plate cover which covers the upper end plate to form an upper end plate cover chamber between the upper end plate cover and the upper end plate, and includes an upper end plate cover discharge hole which communicates with the upper end plate cover chamber and an inner portion of the compressor housing, a lower end plate cover which covers the lower end plate and forms a lower end plate cover chamber between the lower end plate cover and the lower end plate, an upper discharge hole which is provided in the upper end plate and which communicates with the upper compression chamber and the upper end plate cover chamber, a lower discharge hole which is provided in the lower end plate and which communicates with the lower compression chamber and the lower end plate cover chamber, a refrigerant path hole which penetrates the lower end plate, the lower cylinder, the intermediate partition plate, the upper end plate, and the upper cylinder, and communicates with the lower end plate cover chamber and the upper end plate cover chamber, and a reed valve type upper discharge valve which opens and closes the upper discharge hole, and a reed valve type lower discharge valve which opens and closes the lower discharge hole, in which a protruding portion which protrudes downward from a bottom end of the rotation shaft and in which an outer diameter D2is smaller than an outer diameter D1of the sub-bearing unit, is formed on the sub-bearing unit which is provided on the lower endplate and a step portion is formed between the protruding portion and the sub-bearing unit, and, in which a center hole of the lower end plate cover is caused to mate with the protruding portion, and is caused to come into close contact with to the step portion.

In the rotary compressor according to the present invention, a refrigerant gas does not easily flow into the oil feeding vertical hole of the bottom portion of the rotation shaft, even if the refrigerant gas inside the lower end plate cover chamber leaks.

DESCRIPTION OF EMBODIMENTS

Hereafter, detailed description will be given of embodiments (examples) for realizing the present invention with reference to the drawings.

EXAMPLE

FIG. 1is a vertical sectional view illustrating an example of a rotary compressor according to the present invention.FIG. 2is an upward exploded perspective view illustrating a compressing unit of the rotary compressor of the example.FIG. 3is an upward exploded perspective view illustrating a rotation shaft and an oil feeding impeller of the rotary compressor of the example.FIG. 4is a vertical sectional view illustrating the compressing unit of the rotary compressor of the example.

As illustrated inFIG. 1, a rotary compressor1is provided with a compressing unit12, a motor11, and a vertically-placed cylindrical accumulator25. The compressing unit12is disposed on the bottom portion inside a sealed vertically-placed cylindrical compressor housing10, the motor11is disposed above the compressing unit12and drives the compressing unit12via a rotation shaft15, and the accumulator25is fixed to the side surface of the compressor housing10.

The accumulator25is connected to an upper inlet chamber131T (refer toFIG. 2) of an upper cylinder121T via an upper inlet pipe105and an accumulator upper L-pipe31T, and is connected to a lower inlet chamber131S (refer toFIG. 2) of a lower cylinder121S via a lower inlet pipe104and an accumulator lower L-pipe31S.

A discharge pipe107for discharging a refrigerant to a refrigerant circuit (refrigeration cycle) of an air conditioner by penetrating the compressor housing10is provided in the center of the top portion of the compressor housing10. An accumulator inlet pipe255for sucking in the refrigerant from the refrigerant circuit (refrigeration cycle) of the air conditioner by penetrating a housing of the accumulator25is provided in the center of the top portion of the accumulator25.

The motor11is provided with a stator111on the outside, and a rotor112on the inside. The stator111is fixed by shrink-fitting to the inner circumferential surface of the compressor housing10, and the rotor112is fixed by shrink-fitting to the rotation shaft15.

In the rotation shaft15, a sub-shaft unit151which is below a lower eccentric portion152S is fitted and supported, in a free-rotating manner, into a sub-bearing unit161S which is provided on a lower end plate160S, a main shaft unit153which is above an upper eccentric portion152T is fitted and supported, in a free-rotating manner, into a main bearing unit161T which is provided on an upper end plate160T, the upper eccentric portion152T and the lower eccentric portion152S, which are provided with a mutual phase difference of 180°, are fitted, in a free-rotating manner, to an upper piston125T and a lower piston125S, respectively, and thus, the rotation shaft15is supported to rotate freely in relation to the entire compressing unit12. Due to rotation, the upper piston125T and the lower piston125S revolve along the inner circumferential surfaces of the upper cylinder121T and the lower cylinder121S, respectively.

With the aim of lubricating the sliding portions of the compressing unit12and sealing an upper compression chamber133T (refer toFIG. 2) and a lower compression chamber133S (refer toFIG. 2), an amount of a lubricant oil18sufficient to substantially immerse the compressing unit12is sealed in the inner portion of the compressor housing10. An attachment leg310which locks a plurality of elastic supporting members (not illustrated) which support the entire rotary compressor1is fixed to the bottom side of the compressor housing10.

As illustrated inFIG. 2, the compressing unit12is configured by stacking, in order from top, an upper end plate cover170T including a dome-shaped bulging portion, the upper end plate160T, the upper cylinder121T, an intermediate partition plate140, the lower cylinder121S, the lower end plate160S, and a lower end plate cover170S including a dome-shaped bulging portion. The entire compressing unit12is fixed, from top and bottom, by a plurality of penetrating bolts174and175and auxiliary bolts176which are disposed in a substantially concentric manner.

An upper inlet hole135T which mates with the upper inlet pipe105is provided in the ring-shaped upper cylinder121T. A lower inlet hole135S which mates with the lower inlet pipe104is provided in the ring-shaped lower cylinder121S. The upper piston125T is disposed in an upper cylinder chamber130T of the upper cylinder121T. The lower piston125S is disposed in a lower cylinder chamber130S of the lower cylinder121S.

An upper vane groove128T which extends from the upper cylinder chamber130T to the outside in a radial manner is provided in the upper cylinder121T, and an upper vane127T is provided in the upper vane groove128T. A lower vane groove128S which extends from the lower cylinder chamber130S to the outside in a radial manner is provided in the lower cylinder121S, and a lower vane127S is disposed in the lower vane groove128S.

An upper spring hole124T is provided in the upper cylinder121T in a position which overlaps the upper vane groove128T from the outside surface at a depth which does not penetrate the upper cylinder chamber130T, and an upper spring126T is disposed in the upper spring hole124T. A lower spring hole124S is provided in the lower cylinder121S in a position which overlaps the lower vane groove128S from the outside surface at a depth which does not penetrate the lower cylinder chamber130S, and a lower spring126S is disposed in the lower spring hole124S.

The top and bottom of the upper cylinder chamber130T are blocked by the upper end plate160T and the intermediate partition plate140, respectively. The top and bottom of the lower cylinder chamber130S are blocked by the intermediate partition plate140and the lower end plate160S, respectively.

Due to the upper vane127T being pressed by the upper spring126T and caused to abut the outer circumferential surface of the upper piston125T by the upper spring126T, the upper cylinder chamber130T is partitioned into the upper inlet chamber131T which communicates with the upper inlet hole135T, and the upper compression chamber133T which communicates with an upper discharge hole190T which is provided in the upper end plate160T. Due to the lower vane127S being pressed by the lower spring126S and caused to abut the outer circumferential surface of the lower piston125S by the lower spring126S, the lower cylinder chamber130S is partitioned into the lower inlet chamber131S which communicates with the lower inlet hole135S, and the lower compression chamber133S which communicates with a lower discharge hole190S which is provided in the lower end plate160S.

An upper end plate cover chamber180T is formed on the exit side of the upper discharge hole190T between the upper end plate160T and the upper end plate cover170T which includes a dome-shaped bulging portion, which are fixed to each other in close contact. The upper end plate cover chamber180T is provided with a concave portion181T on the upper end plate160T. A reed valve type upper discharge valve200T which prevents the refrigerant from backflowing in the upper discharge hole190T and flowing into the upper compression chamber133T, and an upper discharge valve cap201T which restricts the opening degree of the upper discharge valve200T are accommodated by the concave portion181T.

A lower end plate cover chamber180S is formed on the exit side of the lower discharge hole190S between the lower endplate160S and the lower endplate cover170S which includes a dome-shaped bulging portion, which are fixed to each other in close contact. The lower end plate cover chamber180S is provided with a concave portion181S (refer toFIG. 1) on the lower endplate160S. A reed valve type lower discharge valve200S which prevents the refrigerant from backflowing in the lower discharge hole190S and flowing into the lower compression chamber133S, and a lower discharge valve cap201S which restricts the opening degree of the lower discharge valve200S are accommodated by the concave portion181S.

A refrigerant path hole136is provided which penetrates the lower end plate160S, the lower cylinder121S, the intermediate partition plate140, the upper end plate160T, and the upper cylinder121T and communicates with the lower end plate cover chamber180S and the upper end plate cover chamber180T.

As illustrated inFIG. 3, an oil feeding vertical hole155which penetrates from the bottom end to the top end is provided in the rotation shaft15, and an oil feeding impeller158is press-fitted into the oil feeding vertical hole155. A plurality of oil feeding horizontal holes156which communicate with the oil feeding vertical hole155are provided in the side surface of the rotation shaft15. An outer diameter D4of the sub-shaft unit151of the rotation shaft15is smaller than an outer diameter D3of the main shaft unit153. This is in order to reduce the sliding resistance of the sub-shaft unit151to less than the sliding resistance of the main shaft unit153.

In the related art, an oil feeding pipe (not illustrated) is mounted to the bottom end portion of the oil feeding vertical hole155of the rotation shaft15such that it is possible to suck in the lubricant oil18even when the oil level of the lubricant oil18is low. However, if the outer diameter D4of the sub-shaft unit151is small and the thickness is thin, when the oil feeding pipe is press-fitted into the oil feeding vertical hole155, the sub-shaft unit151deforms, becoming a cause of an increase in the sliding resistance of the rotation shaft15and a decrease in the reliability of the sliding portions. As described in JP-A-2012-202237, a rotary compressor to which an oil feeding pipe is not mounted is proposed; however, such a rotary compressor has the problem described earlier in “2. BACKGROUND ART”.

Next, description will be given of the flow of the refrigerant caused by the rotation of the rotation shaft15. The upper piston125T which is mated with the upper eccentric portion152T of the rotation shaft15revolves along the outer circumferential surface of the upper cylinder chamber130T (inner circumferential surface of the upper cylinder121T) through the rotation of the rotation shaft15inside the upper cylinder chamber130T. Accordingly, the upper inlet chamber131T sucks in the refrigerant from the upper inlet pipe105while expanding in volume, and the upper compression chamber133T compresses the refrigerant while shrinking in volume. If the pressure of the compressed refrigerant becomes higher than the pressure of the upper end plate cover chamber180T of the outside of the upper discharge valve200T, the upper discharge valve200T opens, and the refrigerant is discharged from the upper compression chamber133T to the upper end plate cover chamber180T. The refrigerant which is discharged to the upper end plate cover chamber180T is discharged from an upper end plate cover discharge hole172T (refer toFIG. 1) which is provided in the upper end plate cover170T into the inner portion of the compressor housing10.

The lower piston125S which is mated with the lower eccentric portion152S of the rotation shaft15revolves along the outer circumferential surface of the lower cylinder chamber130S (inner circumferential surface of the lower cylinder121S) through the rotation of the rotation shaft15inside the lower cylinder chamber130S. Accordingly, the lower inlet chamber131S sucks in the refrigerant from the lower inlet pipe104while expanding in volume, and the lower compression chamber133S compresses the refrigerant while shrinking in volume. If the pressure of the compressed refrigerant becomes higher than the pressure of the lower end plate cover chamber180S of the outside of the lower discharge valve200S, the lower discharge valve200S opens, and the refrigerant is discharged from the lower compression chamber133S to the lower end plate cover chamber180S. The refrigerant which is discharged to the lower end plate cover chamber180S passes through the refrigerant path hole136and the upper end plate cover chamber180T, and is discharged into the inner portion of the compressor housing10from the upper end plate cover discharge hole172T (refer toFIG. 1) which is provided in the upper endplate cover170T.

The refrigerant which is discharged into the compressor housing10passes through a top-bottom communicating cutout (not illustrated) which is provided in the outer circumference of the stator111, a gap (not illustrated) in a stator winding111M of the stator111, or a gap115(refer toFIG. 1) between the stator111and the rotor112, is guided to above the motor11, and is discharged from the discharge pipe107of the top portion of the compressor housing10.

Next, description will be given of the flow of the lubricant oil18. The lubricant oil18passes from the bottom end of the rotation shaft15, through the oil feeding vertical hole155and the plurality of oil feeding horizontal holes156, is fed to the sliding surface between the sub-bearing unit161S and the sub-shaft unit151of the rotation shaft15, the sliding surface between the main bearing unit161T and the main shaft unit153of the rotation shaft15, the sliding surface between the lower eccentric portion152S of the rotation shaft15and the lower piston125S, and the sliding surface between the upper eccentric portion152T and the upper piston125T, and lubricates each of the sliding surfaces.

The oil feeding impeller158sucks up the lubricant oil18by applying a centrifugal force to the lubricant oil18inside the oil feeding vertical hole155. Even in a case in which the lubricant oil18is discharged with the refrigerant from inside the compressor housing10, and an oil level is lowered, the oil feeding impeller158serves to reliably supply the lubricant oil18to the sliding surfaces described above.

Next, description will be given of the characteristic configuration of the rotary compressor1of the example, with reference toFIG. 4. As illustrated inFIG. 4, a protruding portion162S which protrudes downward from the bottom end of the rotation shaft15and in which an outer diameter D2is smaller than an outer diameter D1of the sub-bearing unit161S is formed on the sub-bearing unit161S which is provided on the lower end plate160S. A step portion163S is formed between the protruding portion162S and the sub-bearing unit161S. A center hole171S of the lower end plate cover170S is caused to mate with the protruding portion162S, and is caused to come into close contact with the step portion163S of the protruding portion162S.

By adopting the configuration described above, the protruding portion162S serves as a partitioning wall between the center hole171S of the lower end plate cover170S and the oil feeding vertical hole155of the rotation shaft15. In a case in which the refrigerant gas inside the lower end plate cover chamber180S leaks from the center hole171S of the lower endplate cover170S, the refrigerant gas abuts the protruding portion162S and spreads outward. Accordingly, it is possible to prevent the leaked refrigerant gas from flowing in from the oil feeding vertical hole155of the bottom end portion of the rotation shaft15. Therefore, the refrigerant gas is not mixed with the lubricant oil which is sucked up from the bottom end portion of the rotation shaft15, and does not negatively influence the lubrication of the compressing unit12.

In the above, description is given of the examples; however, the examples are not limited by the previously-described content. The previously-described constituent elements include elements which are essentially the same, and so-called elements of an equivalent scope. It is possible to combine the previously-described constituent elements, as appropriate. It is possible to perform at least one of various omissions, replacements, modifications, and any combination thereof of the constituent elements in a scope that does not depart from the gist of the examples.