JP2018059515A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary compressor capable of increasing displacement volume of a compressor or improving efficiency of a compressor without changing the displacement volume, while maintaining reliability that seizure of a bearing does not occur, thereby enabling high output and high efficiency.SOLUTION: A rotary compressor includes an electric motor with a rotor, a crank shaft 4 rotated by the rotor, and a compression mechanism part driven by the crank shaft. The crank shaft has a main shaft 4a fixed to the rotor and an auxiliary shaft 4b provided in an axial direction of the main shaft, and inside the shaft, an oil supply hole 4d for oil supply is formed. For an outer diameter of the auxiliary shaft as φD and a diameter of the oil supply hole as φd, a ratio, φd/φD, is not more than 0.7. With centrifugal pump action of the crank shaft, oil is sufficiently supplied to the compression mechanism part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotary compressor that is used in a refrigeration cycle of a refrigerating and air-conditioning apparatus such as an air conditioner or a refrigerator and compresses refrigerant gas.

  When assembling the compressor, in order to fit the piston to the eccentric portion, the value obtained by subtracting the eccentric amount of the eccentric portion from the radius of the eccentric portion is the same as or larger than the radius of the main shaft or the sub shaft. Need to be. If the value obtained by subtracting the eccentric amount of the eccentric portion from the radius of the main shaft or sub shaft is smaller than the radius of the eccentric portion, pass the main shaft or sub shaft and fit the piston into the eccentric portion. When trying to insert, the outer diameter of the eccentric part and the inner diameter of the piston interfere and cannot be fitted.

  In order to increase the displacement volume in order to increase the capacity of the compressor, it is necessary to reduce the outer diameter of the piston and increase the eccentricity. However, as described above, the value obtained by reducing the eccentric amount of the eccentric portion with respect to the radius of the eccentric portion becomes smaller than the radius of the main shaft or the sub shaft due to the restriction at the time of fitting the piston into the eccentric portion. There was a problem that the amount of eccentricity could not be increased.

  Conventionally, in order to solve this problem, the value obtained by reducing the eccentric diameter of the eccentric portion relative to the radius of the auxiliary shaft by reducing the outer diameter of the auxiliary shaft of the crankshaft to be smaller than the outer diameter of the main shaft. A rotary compressor having the same or larger radius is disclosed (for example, see Patent Document 1).

JP 2011-127430 A

  However, the rotary compressor described in Patent Document 1 increases the displacement volume, that is, when the outer diameter of the piston is reduced and the eccentric amount of the eccentric portion is increased, the crankshaft, the main bearing, the auxiliary bearing, the cylinder, No consideration has been given to the relationship with the oil supply hole provided in the crankshaft, which is essential for oil supply to the compression mechanism formed by pistons, vanes, and the like.

  In order to increase the displacement volume, if the eccentric amount of the eccentric portion is increased, the outer diameter of the auxiliary shaft needs to be reduced accordingly due to the restrictions when assembling the piston as described above. If the outer diameter of the countershaft with the oiling hole inside is reduced, the rigidity of the subshaft decreases and the amount of flexure of the subshaft increases due to the gas load when compressing the refrigerant gas in the compression chamber. The situation worsens, and the shaft and the bearing may seize during operation of the compressor, and the operation of the compressor may be stopped and cannot be restarted.

  In order to increase the efficiency of the compressor, the cylinder height is lowered, and the height of the piston that seals the high pressure side and the low pressure side of the compression chamber is also lowered, so that the refrigerant gas on the high pressure side It is possible to prevent leakage to the low pressure side through the gap, and improve efficiency deterioration due to a decrease in the weight flow rate of the refrigerant gas to be sucked. However, in order to reduce the cylinder height while maintaining the same displacement volume, it is necessary to reduce the outer diameter of the piston and increase the eccentric amount of the eccentric portion of the crankshaft. For this reason, when the outer diameter of the auxiliary shaft having the oil supply hole is reduced as described above, the rigidity of the auxiliary shaft is reduced, and the amount of deflection of the auxiliary shaft is reduced by the gas load when the refrigerant gas is compressed in the compression chamber. As the bearing becomes larger, the lubrication condition of the bearing deteriorates and the shaft and the bearing are seized during the operation of the compressor, the operation of the compressor is stopped, and there is a possibility that it cannot be restarted.

  The present invention is for solving the above-mentioned problems, while maintaining the reliability that does not cause bearing seizure, increasing the displacement volume of the compressor or improving the efficiency of the compressor with the same displacement volume, An object of the present invention is to provide a rotary compressor that can achieve high output and high efficiency.

  The rotary compressor of the present invention includes an electric motor having a rotor, a crankshaft rotated by the rotor, and a compression mechanism unit driven by the crankshaft, and the crankshaft is attached to the rotor. It has a main shaft to be fixed and a sub shaft provided in the axial direction of the main shaft, and an oil supply hole for oil supply is formed inside the shaft, the outer diameter of the sub shaft is φD, and the diameter of the oil supply hole is φd In this case, φd / φD is set to 0.7 or less, and the liquid refrigerant is compressed.

  According to the rotary compressor of the present invention, when the outer diameter of the auxiliary shaft is φD and the diameter of the oil supply hole is φd, φd / φD is set to 0.7 or less, and the liquid refrigerant is compressed. The rigidity of the shaft is improved and the amount of deflection of the secondary shaft due to the liquid load when compressing the liquid refrigerant in the compression chamber is reduced more effectively, and the lubrication of the bearing does not deteriorate and the shaft and the bearing are seized during compressor operation. No. Therefore, it is possible to increase the displacement volume of the compressor or improve the efficiency of the compressor with the same displacement volume while maintaining the reliability that does not cause the seizure of the bearing, thereby achieving higher output and higher efficiency.

It is a schematic block diagram which shows the rotary compressor which concerns on Embodiment 1 of this invention. It is a side view which shows the crankshaft which concerns on Embodiment 1 of this invention. It is a figure which shows (phi) d / (phi) D of the rotary compressor which concerns on Embodiment 1 of this invention, and possibility of reaching seizure. It is sectional drawing which shows the oil supply hole in the crankshaft in the subshaft of the crankshaft which concerns on Embodiment 1 of this invention, and the oil level condition in driving | operation. It is a refrigerant circuit figure which shows an example of the refrigerating-cycle apparatus to which the rotary compressor which concerns on Embodiment 2 of this invention is applied.

  Embodiments of the present invention will be described below. In addition, the form of drawing is an example and does not limit this invention. Moreover, what attached | subjected the same code | symbol in each figure is the same, or is equivalent to this, and this is common in the whole text of a specification. Furthermore, in the following drawings, the relationship between the sizes of the constituent members may be different from the actual one.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram showing a rotary compressor 100 according to Embodiment 1 of the present invention.
In the first embodiment, as the rotary compressor 100, a vertical rotary electric hermetic compressor is shown as an example. The rotary compressor 100 is used in a refrigeration cycle such as an air conditioner.

  As shown in FIG. 1, a rotary compressor 100 has a compression mechanism portion 3 that compresses a refrigerant in a sealed container 1 in a high-pressure atmosphere at a lower portion, and an electric motor (motor portion) 2 that drives the compression mechanism portion 3 at an upper portion. Is arranged. The electric motor 2 includes a stator 2a and a rotor 2b, and is configured to rotate a crankshaft 4 that is a rotating shaft fixed to the rotor 2b, and the compression mechanism unit 3 is driven by the crankshaft 4. Yes.

  The crankshaft 4 includes a main shaft 4a fixed to the rotor 2b of the electric motor 2, a sub shaft 4b provided in the axial direction of the main shaft 4a, and an eccentric portion 4c formed between the main shaft 4a and the sub shaft 4b. Have. An oil supply hole 4 d is formed in the crankshaft 4. The refrigerating machine oil 13 stored in the lower part in the sealed container 1 is supplied to the oil supply hole 4d.

  A compression chamber (not shown) of the compression mechanism 3 includes a rolling piston 8 and a vane 9 provided in the cylinder 7, a main bearing 5 that is a bearing on the upper end surface of the cylinder 7, and a secondary bearing that is a bearing on the lower end surface. It is formed by being sandwiched and closed by the bearing 6. The cylinder 7 has a cylindrical inner space, and a rolling piston 8 that is rotatably fitted to the eccentric portion 4 c of the crankshaft 4 is disposed in the inner space, and is fixed to the inner peripheral portion of the sealed container 1. The

  The main bearing 5 includes a bearing portion 5 a that supports the main shaft 4 a of the crankshaft 4 and an end plate portion 5 b that closes the end surface of the cylinder 7. The bearing portion 5a of the main bearing 5 is fitted to the main shaft 4a of the crankshaft 4 with a clearance for sliding, and rotatably supports the main shaft 4a.

  The auxiliary bearing 6 has a bearing portion 6 a that supports the auxiliary shaft 4 b of the crankshaft 4 and an end plate portion 6 b that closes the end surface on the opposite side of the cylinder 7. The bearing portion 6a of the auxiliary bearing 6 is fitted to the auxiliary shaft 4b of the crankshaft 4 with a clearance for sliding, and rotatably supports the auxiliary shaft 4b.

  An eccentric portion 4c provided on the crankshaft 4 is accommodated in the cylinder 7, and a rolling piston 8 is rotatably mounted on the eccentric portion 4c. A vane 9 is provided to press the tip of the rolling piston 8 with a spring (not shown) or the like, and partitions the inside of the compression mechanism section 3 from the suction chamber (not shown) and the compression chamber.

  Then, the crankshaft 4 is rotated by the electric motor 2, the eccentric portion 4c rotates eccentrically in the cylinder 7, and the suction and compression of the refrigerant gas are repeated. In the compression stroke, the low-pressure refrigerant gas sucked into the suction chamber of the compression mechanism unit 3 is compressed by gradually reducing the volume of the compression chamber as the rolling piston 8 rotates, and becomes high-pressure refrigerant gas. .

  Here, an accumulator 12 is provided adjacent to the sealed container 1. The suction connection pipe 10 connects the cylinder 7 and the accumulator 12.

  The refrigerant gas compressed by the rolling piston 8 and the vane 9 fitted into the eccentric portion 4c of the crankshaft 4 that rotates eccentrically by the rotation of the crankshaft 4 in the cylinder 7 is discharged to the hermetic container 1, and the discharge pipe 11 To the refrigeration cycle of the refrigeration air conditioner.

FIG. 2 is a side view showing the crankshaft 4 according to Embodiment 1 of the present invention.
The crankshaft 4 is an eccentric formed between a main shaft 4a fixed to the rotor 2b of the electric motor 2, a sub shaft 4b provided on the opposite side of the main shaft 4a in the axial direction, and the main shaft 4a and the sub shaft 4b. It has a portion 4 c and an oil supply hole 4 d formed in the crankshaft 4. The oil supply hole 4d is formed as a concentric hollow interior in the sub shaft 4b so that the sub shaft 4b is cylindrical. The oil supply hole 4d opens at the end surface of the sub shaft 4b.
When the outer diameter of the countershaft 4b of the crankshaft is φD, the diameter of the oil supply hole 4d is φd, φd / φD is 0.7 or less, and the diameter of the oil supply hole 4d is 8 mm or more.
Moreover, as an example, the longitudinal elastic modulus of the material of the crankshaft 4 is preferably 15000 to 22000 N / mm ² .

  Since it is configured as described above, for example, when the displacement volume is increased in order to increase the capacity of the rotary compressor 100, in the conventional compressor, when the compressor is assembled, the main shaft is used to fit the piston in the eccentric portion. Alternatively, the value obtained by subtracting the eccentric amount of the eccentric portion with respect to the radius of the sub shaft needs to be the same as or larger than the radius of the eccentric portion. On the other hand, to increase the displacement volume, the value obtained by subtracting the eccentric amount of the eccentric part from the outer diameter of the auxiliary shaft with respect to the radius of the auxiliary shaft is the same as or larger than the radius of the eccentric part. The outer diameter had to be reduced, leading to a reduction in crankshaft rigidity. However, according to the first embodiment, the rigidity of the crankshaft 4 can be increased by setting the ratio φd / φD of the outer diameter φD of the auxiliary shaft 4b of the crankshaft 4 and the diameter φd of the oil supply hole 4d to 0.7 or less. it can.

FIG. 3 is a diagram showing φd / φD of the rotary compressor 100 according to Embodiment 1 of the present invention and the possibility of burn-in.
As shown in FIG. 3, it was confirmed by experiment whether or not the value of φd / φD was changed and burn-in was reached. When φd / φD was greater than 0.7, surface roughness due to abrasion of the sliding surface, which was a sign of seizure, was observed. In the range where φd / φD was 0.7 or less, although wear was recognized, it was in a smooth wear state and did not cause seizure.

FIG. 4 is a cross-sectional view showing the oil supply hole 4d in the crankshaft 4 and the oil level during operation in the auxiliary shaft 4b of the crankshaft 4 according to Embodiment 1 of the present invention.
The oil supply hole 4d provided in the crankshaft 4 has a centrifugal structure, and a plate is fitted therein, and the refrigerating machine oil 13 is rotated together with the rotation of the crankshaft 4 so that a reverse parabolic shape is formed inside the crankshaft 4. A (concave shape) oil surface shape is created, and the refrigerating machine oil 13 retained in the rotary compressor 100 is supplied to the compression mechanism unit 3 via an oil supply path provided in the crankshaft 4. However, if the diameter of the oil supply hole 4d is small, the rotational circumferential speed of the refrigerating machine oil 13 is also small and a sufficient reverse parabolic shape cannot be obtained, and the oil level cannot be raised to the height of the oil supply hole 4d. There is a possibility that the lubrication state of the sub-bearing 6 is deteriorated and the crankshaft 4, the main bearing 5 and the sub-bearing 6 are seized during the operation of the compressor, and the operation of the rotary compressor 100 is stopped and cannot be restarted.
As shown in FIG. 4, when the inner diameter of the oil supply hole 4d is less than 8 mm, the peripheral speed of the refrigerating machine oil 13 that rotates in synchronization with the crankshaft 4 is insufficient, and the refrigerating machine oil 13 does not rise to a sufficient height. Lubrication to part 3 is not enough. However, by setting the inner diameter (diameter) of the oil supply hole 4d to 8 mm or more, the peripheral speed of the refrigerating machine oil 13 that rotates in synchronization with the crankshaft 4 is satisfied, and the oil surface 50 is brought into the oil supply hole 4d to a sufficient height. A reverse parabolic (concave shape) oil surface shape is created and heightened, and the oil supply to the compression mechanism unit 3 can be sufficiently performed.

  In Embodiment 1 described above, the rolling piston 8 and the vane 9 are separately provided. Next, the rotary compressor 100 in which the rolling piston 8 and the vane 9 are integrated will be described.

  In normal operation, the refrigerant sucked and compressed by the rotary compressor 100 is a gas of a compressive fluid. However, when the rotary compressor 100 is started up or when it is operated at a low ambient temperature, the rotary compressor is operated from the refrigeration cycle side. In some cases, an incompressible fluid liquid refrigerant is drawn into the compressor.

  If the liquid refrigerant, which is an incompressible fluid, is sucked and compressed, the pressure in the compression chamber rises rapidly, and an excessive load is also applied to the main bearing 5 and the sub-bearing 6 that receive the compression load. Become.

  In the rotary compressor 100 in which the rolling piston 8 and the vane 9 are separate from each other, when such pressure is rapidly increased in the compression chamber, pressure is also applied to the vane 9 so that an outward force is exerted from the compression chamber. The vane 9 is separated from the piston 8, and the high pressure side and the low pressure side of the compression chamber communicate with each other to prevent a pressure increase. By reducing the bearing load on the main bearing 5 and the sub-bearing 6, damage to the bearing is prevented. It is preventing.

  However, in the rotary compressor 100 in which the rolling piston 8 and the vane 9 are integrally formed, a rapid pressure increase in the compression chamber as described above cannot be prevented, and an excessive load is applied to the bearing. Will increase the risk of damage. For this reason, the crank is obtained by setting φd / φD, which is the ratio of the outer diameter φD of the countershaft 4b of the crankshaft 4 described in Embodiment 1 and the diameter φd of the oil supply hole 4d inside the crankshaft 4, to 0.7 or less. The effect of increasing the rigidity of the shaft 4 becomes more effective when compressing a liquid refrigerant that is an incompressible fluid.

  In the first embodiment, the main shaft 4a and the sub shaft 4b have substantially the same outer shape. However, the outer diameter φD of the sub shaft 4b is made thinner than the outer shape of the main shaft 4a, and the rolling piston 8 is connected to the sub shaft 4b. You may make it attach to the eccentric part 4c through the axis | shaft 4b side. Since the sub shaft 4b has a shorter shaft length than the main shaft 4a, there is an effect that it can be easily mounted on the eccentric portion 4c of the rolling piston 8.

  According to the first embodiment described above, when the outer diameter of the sub shaft 4b is φD and the diameter of the oil supply hole 4d provided in the shaft is φd, φd / φD is 0.7 or less. The rigidity of 4b is improved, the amount of bending of the auxiliary shaft 4b due to the gas load when compressing the refrigerant gas in the compression chamber is reduced, and the lubrication state of the main bearing 5 and the auxiliary bearing 6 is not deteriorated, and the crankshaft 4 and the main bearing 5 And the auxiliary bearing 6 is not seized during the compressor operation. Therefore, while maintaining the reliability that the seizure of the main bearing 5 and the sub bearing 6 does not occur, the displacement of the refrigerant of the rotary compressor 100 is increased, or the efficiency of the rotary compressor 100 is improved with the same displacement. High output and high efficiency can be achieved.

  Further, since the diameter of the oil supply hole 4d is set to 8 mm or more, in addition to the above-described effect of not seizing, the diameter of the oil supply hole 4d is large and the rotational circumferential speed of the refrigerating machine oil 13 is increased, so that a sufficient reverse parabolic shape is obtained. The oil level 50 can be lifted up to the height of the oil supply hole 4d, and the lubrication condition of the main bearing 5 and the sub bearing 6 is improved. Therefore, while maintaining the reliability that the seizure of the main bearing 5 and the sub bearing 6 does not occur, the displacement of the refrigerant of the rotary compressor 100 is increased, or the efficiency of the rotary compressor 100 is improved with the same displacement. High output and high efficiency can be achieved. Moreover, what can fully supply oil to the compression mechanism part 3 of the refrigerator oil 13 is obtained.

  Further, since the outer diameter φD of the auxiliary shaft 4b is configured to be smaller than the outer diameter of the main shaft 4a, the rolling piston 8 can be easily mounted on the eccentric portion 4c, and the eccentric amount is increased. The displacement volume of the refrigerant can be increased or the efficiency of the rotary compressor 100 can be improved while maintaining the same displacement volume, and higher output and higher efficiency can be achieved.

  Further, since the rolling piston 8 is inserted into the eccentric portion 4c through the countershaft 4b of the crankshaft 4, the rolling piston 8 can be easily attached to the eccentric portion 4c, and the amount of eccentricity is increased. Further, the displacement of the refrigerant in the rotary compressor 100 can be increased or the efficiency of the rotary compressor 100 can be improved while maintaining the same displacement volume, thereby achieving higher output and higher efficiency.

  When the rolling piston 8 and the vane 9 are integrally formed, the ratio φd / φD, which is the ratio of the outer diameter φD of the auxiliary shaft 4b of the crankshaft 4 and the diameter φd of the oil supply hole 4d inside the crankshaft 4, is 0.7 or less. The above-described non-burn-in effect is more effective when compressing a liquid refrigerant that is an incompressible fluid.

Further, since the longitudinal elastic modulus of the crankshaft 4 is 15000 to 22000 N / mm ² , wear of the main bearing 5 and the sub-bearing 6 can be prevented.

Embodiment 2. FIG.
FIG. 5 is a refrigerant circuit diagram showing an example of a refrigeration cycle apparatus 200 to which the rotary compressor 100 according to Embodiment 2 of the present invention is applied.
A refrigeration cycle apparatus 200 shown in FIG. 5 forms a refrigeration cycle circuit in which a rotary compressor 100, a condenser 201, an expansion valve 202, and an evaporator 203 are connected by refrigerant piping. Then, the refrigerant that has flowed out of the evaporator 203 is sucked into the rotary compressor 100 and compressed to become high temperature and high pressure. The refrigerant that has become high temperature and high pressure is condensed in the condenser 201 to become a liquid. The refrigerant that has become liquid is decompressed and expanded by the expansion valve 202 to become a low-temperature and low-pressure gas-liquid two-phase, and the refrigerant in the gas-liquid two-phase state is heat-exchanged by the evaporator 203.
The rotary compressor 100 can be applied to the refrigeration cycle apparatus 200 as described above.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Electric motor, 2a Stator, 2b Rotor, 3 Compression mechanism part, 4 Crankshaft, 4a Main shaft, 4b Subshaft, 4c Eccentric part, 4d Oil supply hole, 5 Main bearing, 5a Bearing part, 5b End Plate part, 6 Sub bearing, 6a Bearing part, 6b End plate part, 7 Cylinder, 8 Rolling piston, 9 Vane, 10 Suction connection pipe, 11 Discharge pipe, 12 Accumulator, 13 Refrigerating machine oil, 50 Oil level, 100 Rotary compressor , 200 refrigeration cycle apparatus, 201 condenser, 202 expansion valve, 203 evaporator.

Claims (6)

An electric motor having a rotor;
A crankshaft rotated by the rotor;
A compression mechanism driven by the crankshaft,
The crankshaft is
It has a main shaft fixed to the rotor and a sub shaft provided in the axial direction of the main shaft, and an oil supply hole for oil supply is formed inside the shaft,
When the outer diameter of the auxiliary shaft is φD and the diameter of the oil supply hole is φd, φd / φD is 0.7 or less,
A rotary compressor that compresses liquid refrigerant.   The rotary compressor according to claim 1, wherein the oil supply hole has a diameter of 8 mm or more.   The rotary compressor according to claim 1 or 2, wherein an outer diameter of the auxiliary shaft is smaller than an outer diameter of the main shaft. The crankshaft is
Having an eccentric portion formed between the main shaft and the sub shaft;
The compression mechanism is
A piston that is slidably fitted to the eccentric part of the crankshaft;
The rotary compressor according to claim 3, wherein the piston is fitted into the eccentric portion by passing through the countershaft of the crankshaft. The crankshaft is
Having an eccentric portion formed between the main shaft and the sub shaft;
The compression mechanism is
A piston slidably fitted to the eccentric part of the crankshaft;
A vane formed integrally with the piston;
The rotary compressor of any one of Claims 1-4 provided with these. Rotary compressor according to any one of claims 1 to 5, longitudinal elastic coefficient is 15000~22000N / mm ² of the crank shaft.

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