Accumulator, Compressor, and Refrigeration Cycle Apparatus

This application claims the benefit of priority of Japanese Patent Application No. 2024-087783, filed on May 30, 2024, the entire contents of which are incorporated herein by reference.

Embodiments according to the present invention relate to an accumulator, a compressor, and a refrigeration cycle apparatus.

To prevent a liquid refrigerant from being supplied into and compressed in a cylinder of a compressor, what is called liquid compression, there is known an accumulator (gas-liquid separator, liquid separator) disposed on a suction side of the compressor (for example, Japanese Patent Laid-Open No. H04-350479).

To secure gas-liquid separation capacity, a conventional accumulator includes a container, a partition plate that divides an internal space of the container into upper and lower spaces, a straight pipe that vertically extends to passe through the partition plate to open in a bottom space, and an outlet pipe that opens in the bottom space to be led out from a lower surface of the container.

A lower end of the straight pipe, that is, an outlet end of the straight pipe, is disposed in a vicinity of the partition plate. An upper end of the outlet pipe, that is, an inlet end of the outlet pipe, is disposed in a vicinity of a bottom plate of the container. That is, the outlet end of the straight pipe is disposed above the inlet end of the outlet pipe.

In the conventional accumulator, when a liquid refrigerant flows into the bottom space of the container through the straight pipe, this liquid refrigerant easily flows into the outlet pipe having the inlet end in the vicinity of the bottom plate of the container. This may cause liquid compression in the compressor.

On the other hand, the accumulator temporarily catches refrigerating machine oil that is discharged from the compressor together with the refrigerant and circulates in a refrigerating cycle to return to the compressor, and returns the caught refrigerating machine oil to the compressor. At this point, similarly to the liquid compression of the refrigerant, it is not preferable that the refrigerating machine oil at an excessive flow rate returns to the compressor from the accumulator.

Thus, an object of the present invention is to provide an accumulator, a compressor including this accumulator, and a refrigeration cycle apparatus, wherein the accumulator can achieve both of gas-liquid separation capacity that can securely prevent a liquid refrigerant from flowing out, in other words, gas-liquid separation capacity that can securely prevent liquid compression in the compressor, and adjustment of an oil return flow rate to return caught refrigerating machine oil to the compressor at an appropriate flow rate.

To resolve the above problems, an accumulator according to an embodiment of the present invention includes: a container; a partition plate that is disposed inside the container, and divides an internal space of the container into a refrigerant introduction chamber and a refrigerant discharge chamber; an inlet pipe that is fixed to the container and includes an inlet flow channel connected to the refrigerant introduction chamber; at least one communication pipe including a communication flow channel that passes through the partition plate to connect the refrigerant introduction chamber with the refrigerant discharge chamber; and at least one outlet pipe that is fixed to the container and includes an outlet flow channel connected to the refrigerant discharge chamber. The at least one communication pipe includes an outlet opening disposed in the refrigerant discharge chamber and at least one introduction-side refrigerating machine oil return hole disposed in the refrigerant introduction chamber. The at least one outlet pipe includes an inlet opening disposed in the refrigerant discharge chamber and at least one discharge-side refrigerating machine oil return hole disposed in the refrigerant discharge chamber. Oil returning capability of the at least one discharge-side refrigerating machine oil return hole is higher than oil returning capability of the at least one introduction-side refrigerating machine oil return hole.

To resolve the above problems, a compressor according to another embodiment of the present invention includes: a sealed container; a compression mechanism housed in the sealed container; an electric motor that is housed in the sealed container and generates driving force of the compression mechanism; and the accumulator that is placed outside the sealed container and connected to a suction side of the compression mechanism.

To resolve the above problems, a refrigeration cycle apparatus according to another embodiment of the present invention includes: the compressor; a radiator; an expansion device; a heat absorber; and a refrigerant piping that connects the compressor, the radiator, the expansion device, and the heat absorber to circulate a refrigerant.

The following describes embodiments of an accumulator, a compressor, and a refrigeration cycle apparatus according to the present invention with reference toto. Throughout a plurality of drawings, same or corresponding configurations are denoted by the same reference numeral.

is a schematic diagram of the refrigeration cycle apparatus, the compressor, and the accumulator according to the embodiment of the present invention.

As illustrated in, a refrigeration cycle apparatusaccording to the present embodiment includes a rotary compressor, a radiator, an expansion device, a heat absorber, an accumulator, and a refrigerant piping. The rotary compressoris simply referred to as a “compressor” hereinafter. The refrigerant pipingsuccessively connects the compressor, the radiator, the expansion device, the heat absorber, and the accumulatorto circulate a refrigerant. The refrigerant that circulates in the refrigeration cycle apparatusis any of various refrigerants such as a carbon dioxide refrigerant, a R32 refrigerant, and a mixed refrigerant including R32 refrigerant. The radiatormay also be called a condenser, and the heat absorbermay also be called an evaporator.

The compressorincludes a cylindrical-shaped sealed containerthat is vertically disposed, an electric motorhoused in an upper half portion of the sealed container, a compression mechanismhoused in a lower half portion of the sealed container, a crank shaftthat transmits rotational driving force of the electric motorto the compression mechanism, and a main bearingand an auxiliary bearingcooperating with each other to support the crank shaftin a rotatable manner.

The sealed containerhas a cylindrical shape. The sealed containerincludes a cylindrical-shaped drumextending in an upper and lower direction, a hemispherical-shaped or elliptical-shaped upper end platethat blocks an upper end portion of the drum, and a hemispherical-shaped or elliptical-shaped lower end platethat blocks a lower end portion of the drum

The drumsupports a plurality of suction pipesguiding the refrigerant to the compressor. The suction pipesare connected to the accumulator. The suction pipesare part of the refrigerant piping.

The upper end platesupports a discharge pipethat discharges the refrigerant compressed by the compressor. The discharge pipeis connected to the refrigerant piping. The upper end plateincludes a sealed terminal portionthat supplies electric power to the electric motor.

The electric motorgenerates driving force to rotate the compression mechanism. The electric motoris, for example, a Permanent Magnet Synchronous Motor (PMSM). The electric motorincludes a tubular-shaped statorfixed to an inner wall of the sealed container, a rotorthat is disposed on an inner side of the statorand fixed to the crank shaft, and a plurality of lead wiresled out from the statorand connected to the sealed terminal portion.

The rotorincludes a rotor core having a magnet housing hole, and a permanent magnet housed in the magnet housing hole. The rotorcan rotate with respect to the stator, and fixed to the crank shaftto be integrally rotatable therewith. Rotation center lines of the rotorand the crank shaftsubstantially agree with a center line of the stator.

The lead wiresare wiring for supplying electric power to the statorthrough the sealed terminal portion, what is called leads. The lead wiresare wired in accordance with a type of the electric motor. In a case in which the lead wiresare used as an open-winding type, two lead wiresare wired for each of a U-phase, a V-phase, and a W-phase, that is, the six lead wiresin total are wired. In a case in which the electric motoris used with a star connection, one lead wireis wired for each of the U-phase, the V-phase, and the W-phase, that is, the three lead wiresin total are wired.

The crank shaftcouples the electric motorwith the compression mechanism. The crank shafttransmits driving force generated by the electric motorto the compression mechanism.

An intermediate portionof the crank shaftconnects the electric motorwith the compression mechanism, and is supported by the main bearingin a rotatable manner. A lower end portionof the crank shaftis supported by the auxiliary bearingin a rotatable manner. The main bearingand the auxiliary bearingare part of the compression mechanism. In other words, the crank shaftpasses through the compression mechanism.

The crank shaftincludes a plurality of eccentric portionsandbetween the intermediate portionsupported by the main bearingand the lower end portionsupported by the auxiliary bearing. Of the eccentric portions, a portion closer to the main bearingis referred to as a first eccentric portion, and a portion closer to the auxiliary bearingis referred to as a second eccentric portion. Each of the eccentric portionsandis a disk or a cylinder having a center not agreeing with the center of the crank shaft. The center of each of the eccentric portionsandis decentered with a phase difference of about 180 degrees around the crank shaft. The first eccentric portionis placed on an upper side closer to the electric motor, and the second eccentric portionis placed on a lower side distant from the electric motor.

The main bearingon the upper side is fixed to a framevia a first cylinderby a plurality of fastening members, for example, boltsand. The frameis fixed to the sealed containerat a plurality of points by welding, for example, spot welding. That is, the framesupports the compression mechanism, the crank shaft, and the rotorof the electric motoron the sealed container.

When the electric motorcoupled to the compression mechanismvia the crank shaftis rotated and driven, the compression mechanismsucks a gaseous refrigerant through the suction pipes, compresses the sucked refrigerant, and discharges the compressed refrigerant into the sealed container. A lower portion of the sealed containeris filled with refrigerating machine oil, and a major portion of the compression mechanismis immersed in the refrigerating machine oil.

The compression mechanismincludes more than one, for example, two rotor-cylinder assembliesand. In other words, the compressoris a multi-cylinder rotary compressor. The compression mechanismincludes the first rotor-cylinder assemblydisposed inside the sealed container, the second rotor-cylinder assemblydisposed inside the sealed container, and a partition platedisposed between the first rotor-cylinder assemblyand the second rotor-cylinder assembly.

The compressormay be a multi-cylinder rotary compressor having three or more cylinders, or may be a rotary compressor having a single cylinder. The compressorand the accumulatorare connected via the suction pipesthe number of which is the same as the number of the cylinders.

The first rotor-cylinder assemblyincludes the first cylinderincluding a circular-shaped first cylinder chamber, and an annular-shaped first rolling pistondisposed inside the first cylinder chamber. The first rolling pistonis simply referred to as a “first piston” hereinafter.

The second rotor-cylinder assemblyincludes a second cylinderincluding a circular-shaped second cylinder chamber, and an annular-shaped second rolling pistondisposed inside the second cylinder chamber. The second rolling pistonis simply referred to as a “second piston” hereinafter.

Each of the rotor-cylinder assembliesandincludes a vanethat partitions corresponding one of the cylinder chambersandinto a suction chamber and a compression chamber by performing reciprocating motion for approaching or moving away from a rotation center line of the crank shaftwhile being in contact with an outer peripheral surfaces of corresponding one of the pistonsand. Each of the rotor-cylinder assembliesandchanges capacity of the compression chamber sectioned by corresponding one of the pistonsandand the corresponding vaneby rotation of the pistonsandto compress the refrigerant. Only the vaneof the second rotor-cylinder assemblyis illustrated in.

The first cylinderand the second cylinderare disposed to be stacked in an axis direction of the crank shaft. The first cylinderon the upper side is disposed on a side closer to the electric motor. The second cylinderon the lower side is disposed on a side distant from the electric motor.

Each of the cylindersandincludes an inner peripheral surface that defines corresponding one of the cylinder chambersand. Each of the cylindersandhas an annular shape and a plate shape including corresponding one of the cylinder chambersandinside. Each of the cylindersandhas an end face close to the electric motorand an end face distant from the electric motor.

Centers of the first cylinder chamberand the second cylinder chambersubstantially overlap the rotation center line of the crank shaft. These cylinder chambersandhave substantially the same diameter dimension and height dimension, that is, a dimension in a length direction of the crank shaft. The first cylinder chamberis a space inside the first cylinder, and closed by the main bearingand the partition plate. The first cylinder chamberhouses the first eccentric portionof the crank shaft. The second cylinder chamberis a space inside the second cylinder, and closed by the partition plateand the auxiliary bearing. The second cylinder chamberhouses the second eccentric portionof the crank shaft.

The compression mechanismincludes a first discharge valve mechanism including a discharge port that is disposed on the main bearingto discharge the refrigerant compressed inside the first cylinder chamberto the outside of the first cylinder chamberand a discharge valve that is disposed on the main bearingto open and close the discharge port, and a first discharge mufflerthat is disposed on the main bearingto cover the first discharge valve mechanism.

The discharge port of the first discharge valve mechanism is connected to the first cylinder chamber.

The discharge valve of the first discharge valve mechanism opens the discharge port when a differential pressure between an inside and an outside of the first cylinder chamberreaches a predetermined differential pressure value in association with compression action of the compression mechanism, and discharges the compressed refrigerant into the first discharge muffler.

The first discharge mufflercovers the first discharge valve mechanism. The first discharge mufflerhas a discharge hole passing through the first discharge muffler. The compressed refrigerant discharged into the first discharge muffleris discharged into the sealed containerthrough the discharge hole.

The first discharge mufflerand the first cylinderare fixed to the main bearingby a plurality of fastening members, for example, the bolts. The boltpasses through the first discharge mufflerand the main bearingto reach the first cylinder.

The compression mechanismalso includes a second discharge valve mechanism including a discharge port that is disposed on the auxiliary bearingto discharge the refrigerant compressed inside the second cylinder chamberand a discharge valve that is disposed on the auxiliary bearingto open and close the discharge port, and a second discharge mufflerthat is disposed on the auxiliary bearingto cover the second discharge valve mechanism.

The discharge port of the second discharge valve mechanism is connected to the second cylinder chamber.

The discharge valve of the second discharge valve mechanism opens the discharge port when a differential pressure between an inside and an outside of the second cylinder chamberreaches a predetermined differential pressure value in association with compression action of the compression mechanism, and discharges the compressed refrigerant into the second discharge muffler.

The second discharge mufflercovers the second discharge valve mechanism. The compressed refrigerant discharged into the second discharge muffleris guided to the first discharge mufflerthrough a hole passing through the auxiliary bearing, the second cylinder, the partition plate, and the first cylinder, and discharged into the sealed container.

The second discharge muffler, the auxiliary bearing, the second cylinder, and the partition plateare fixed to the first cylinderby a plurality of fastening members, for example, bolts. The boltpasses through the second discharge muffler, the auxiliary bearing, the second cylinder, and the partition plateto reach the first cylinder.

The first pistonis engaged with a peripheral surface of the first eccentric portionand housed in the first cylinder chamber. The first pistoneccentrically moves while causing part of the outer peripheral surface to be in line contact with an inner peripheral surface of the first cylinder chamberin association with rotation of the crank shaft.

The second pistonis engaged with a peripheral surface of the second eccentric portionand housed in the second cylinder chamber. The second pistoneccentrically moves while causing part of the outer peripheral surface to be in line contact with an inner peripheral surface of the second cylinder chamberin association with rotation of the crank shaft.

Contact between the first pistonand the first cylinder, and contact between the second pistonand the second cylinderare not direct contact but indirect contact with an oil film (not illustrated) interposed therebetween. For convenience of explanation, the contact via the oil film is simply referred to as “contact”. The same applies to contact between the first pistonand the first eccentric portion, contact between the second pistonand the second eccentric portion, contact between the first pistonand the main bearing, contact between the second pistonand the auxiliary bearing, contact between the first pistonand the partition plate, and contact between the second pistonand the partition plate.

The accumulatoris fixed to the sealed containerof the compressorwith a clamp band.

andare vertical cross-sectional views of the accumulator according to the embodiment of the present invention.

As illustrated inandin addition to, the accumulatoraccording to the present embodiment includes a cylindrical-shaped containersupported in an upright state, a partition platethat is disposed inside the containerto divide an internal space S of the containerinto a refrigerant introduction chamber IR and a refrigerant discharge chamber OR, an inlet pipethat is fixed to the containerand has an inlet flow channel IP connected to the refrigerant introduction chamber IR, at least one communication pipethat passes through the partition plateand has a communication flow channel CP connecting the refrigerant introduction chamber IR with the refrigerant discharge chamber OR, and a plurality of outlet pipesfixed to the containerand each having an outlet flow channel OP connected to the refrigerant discharge chamber OR.