Patent Grant
10578103
This application is a U.S. national stage application of International Application No. PCT/JP2015/066929, filed on Jun. 11, 2015, the contents of which are incorporated herein by reference.
The present invention relates to a scroll compressor and a refrigeration cycle apparatus that are mounted mainly in refrigerators, air-conditioners, and water heaters.
Hitherto, a scroll compressor has been known in which a fixed scroll and an orbiting scroll each having a scroll wrap are engaged with each other so as to form compression chambers in cooperation with each other (see, for example, Patent Literature 1). In this scroll compressor, injection ports are formed in a baseplate of the fixed scroll. By causing liquid refrigerant to flow through the injection ports into compression chambers at an intermediate pressure, the gas temperature in the compression chambers is lowered, the temperature of refrigerant discharged from the compression chambers (hereinafter referred to as discharge temperature) is reduced, and efficiency is increased.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2012-127222
In recent years, from the viewpoint of preventing global warming, the transition from conventional HFC refrigerant to refrigerant with low GWP has been progressing. For example, carbon dioxide is a candidate refrigerant that has a GWP lower than that of HFC refrigerant. Carbon dioxide is, owing to its physical property, a refrigerant that tends to have high operating pressure and high discharge temperature.
In a scroll compressor, as sealing portions that seal the axial gap between adjacent compression chambers, tip seal members are disposed on the tip surfaces of scroll wraps of a fixed scroll and an orbiting scroll. When carbon dioxide is used as refrigerant in a scroll compressor in which tip seal members are disposed on the tips surfaces of scroll wraps, the following problem arises. That is, since the use of carbon dioxide increases the pressure in the compression chambers as described above, the pressure difference between the pressure in the injection ports when injection is stopped and the pressure in the compression chambers is large. There is a problem in that when, during the eccentric revolving motion of the orbiting scroll, the tip seal member on the orbiting scroll passes over the injection ports, the tip seal member enters the injection ports owing to this pressure difference, and the tip seal member breaks.
The present invention has been made to overcome the above problem, and provides a scroll compressor and a refrigeration cycle apparatus in which the breakage of a tip seal member can be prevented and the reliability can be improved.
A scroll compressor according to an embodiment of the present invention includes a shell, a fixed scroll and an orbiting scroll disposed in the shell, scroll wraps that are provided in the fixed scroll and the orbiting scroll and that are engaged with each other to form a plurality of compression chambers, a crankshaft that causes the orbiting scroll to perform eccentric revolving motion, a tip seal member that is inserted in the tip of the scroll wrap of the orbiting scroll along the spiral direction and that is in sliding contact with the baseplate of the fixed scroll, and injection ports that are provided through the baseplate of the fixed scroll and that introduce refrigerant at an intermediate pressure between suction pressure and discharge pressure into the compression chambers from the outside. The refrigerant is composed only of carbon dioxide or is a mixed refrigerant containing carbon dioxide. The diameter ϕinj of the injection ports and the width TIP of the tip seal member in a direction perpendicular to the spiral direction have the relationship of ϕinj≤0.95×TIP.
A refrigeration cycle apparatus according to an embodiment of the present invention includes a main circuit that has a scroll compressor, a radiator, a decompression device, and an evaporator and that is configured such that these are connected in order with pipes and refrigerant circulates therethrough, an intermediate injection circuit that branches from between the radiator and the decompression device and that is connected to the injection ports of the scroll compressor, and a flow control valve that adjusts the flow rate of the intermediate injection circuit. Refrigerant in a liquid state is guided from the intermediate injection circuit to the injection ports.
According to an embodiment of the present invention, since the diameter ϕinj of the injection ports and the width TIP of the tip seal member have the relationship of ϕinj≤0.95×TIP, a scroll compressor and a refrigeration cycle apparatus can be obtained in which the breakage of a tip seal member can be prevented and the reliability can be improved.
Embodiment 1 will be described below with reference to the drawings. In the following drawings, elements denoted by the same reference signs are same or equivalent, and this commonly applies through the embodiments. The forms of components described in the entire description are merely illustrative and no restrictive. For the expressions of high, low, and the like in temperature, pressure, and the like, being high, low, or the like is not determined on the basis of a relationship with any absolute value, but is relatively determined in a state, action, or the like in a system, apparatus, or the like.
This scroll compressor 100 has a function of suctioning refrigerant and compressing the refrigerant into a high temperature and high pressure refrigerant to be discharged. The scroll compressor 100 is configured to house a compression mechanism unit 35, a drive mechanism unit 36, and other components in a shell 8 that is a hermetic container forming an enclosure. As shown in
Inside the shell 8, a frame 3 and a sub-frame 19 are disposed so as to face each other with the drive mechanism unit 36 therebetween. The frame 3 is disposed above the drive mechanism unit 36 and is located between the drive mechanism unit 36 and the compression mechanism unit 35, and the sub-frame 19 is located below the drive mechanism unit 36. The frame 3 and the sub-frame 19 are fixed to the inner peripheral surface of the shell 8 by shrink fit, welding, or the like. A bearing portion 3b is provided in the center of the frame 3, and a sub-bearing 19a is provided in the center of the sub-frame 19. A crankshaft 4 is rotatably supported by the bearing portion 3b and the sub-bearing 19a.
A suction pipe 5 for suctioning refrigerant, a discharge pipe 13 for discharging refrigerant, and an injection pipe 15 for injecting refrigerant into compression chambers 9 are connected to the shell 8.
The compression mechanism unit 35 has a function of compressing refrigerant suctioned through the suction pipe 5 and discharging it to a high-pressure space 14 formed in an upper part of the shell 8. This high-pressure refrigerant is discharged through the discharge pipe 13 to the outside of the scroll compressor 100. The drive mechanism unit 36 serves a function of driving an orbiting scroll 2 that makes up the compression mechanism unit 35 to compress refrigerant in the compression mechanism unit 35. That is, the drive mechanism unit 36 drives the orbiting scroll 2 through the crankshaft 4, and refrigerant is thereby compressed in the compression mechanism unit 35.
The compression mechanism unit 35 has a fixed scroll 1 and an orbiting scroll 2. As shown in
The fixed scroll 1 is fixed in the shell 8 via the frame 3. A discharge port 1a that discharges refrigerant compressed to a high pressure is formed in the center of the fixed scroll 1. At the outlet opening of the discharge port 1a, a valve 11 formed of a blade spring is disposed to cover the outlet opening and prevent backflow of refrigerant. At one end of the valve 11, a valve guard 10 is provided that limits the amount of lift of the valve 11. That is, when refrigerant is compressed to a predetermined pressure in the compression chambers 9, the valve 11 is lifted up against its elastic force. The compressed refrigerant is discharged through the discharge port 1a into the high-pressure space 14, and is discharged through the discharge pipe 13 to the outside of the scroll compressor 100.
In the first baseplate 1c of the fixed scroll 1, injection ports 16 are formed at positions not communicating with a low-pressure space (suction pressure space). The injection ports 16 are ports for injecting liquid refrigerant at an intermediate pressure (pressure between suction pressure and discharge pressure) from the outside of the shell 8 into the compression chambers 9 in which refrigerant in the process of being compressed exists. The injection ports 16 are provided one for each of a pair of compression chambers 9 symmetrical with respect to a center of the first scroll wrap 1b and the second scroll wrap 2b, and are configured such that the pressures in the pair of symmetrical compression chambers 9 are equal to each other.
In the fixed scroll 1, an injection distribution channel 15a is formed that divides injection refrigerant supplied from the injection pipe 15 into two and causes them to flow into the two injection ports 16. Although, in
The orbiting scroll 2 performs an eccentric revolving motion relative to the fixed scroll 1 without rotating. A hollow cylindrical recessed bearing 2d that receives driving force is formed substantially in the center of a surface (hereinafter referred to as thrust surface) of the orbiting scroll 2 that is opposite to the surface on which the second scroll wrap 2b is formed. A later-described eccentric pin portion 4a provided at the upper end of the crankshaft 4 is fitted in (engaged with) the recessed bearing 2d.
A tip seal member 17a and a tip seal member 17b are inserted in the tips of the first scroll wrap 1b and the second scroll wrap 2b of the fixed scroll 1 and the orbiting scroll 2 along the spiral direction as shown by the blackened parts in
The drive mechanism unit 36 at least includes a stator 7, a rotor 6 that is rotatably disposed on the inner peripheral surface side of the stator 7 and that is fixed to the crankshaft 4, and the crankshaft 4 that is housed vertically in the shell 8 and that is a rotating shaft. The stator 7 is configured to rotationally drive the rotor 6 by being energized. The outer peripheral surface of the stator 7 is fixed to and supported by the shell 8 by shrink fit or the like. The rotor 6 is configured to be rotationally driven when the stator 7 is energized, and rotating the crankshaft 4. The rotor 6 is fixed to the outer peripheral surface of the crankshaft 4, has a permanent magnet therein, and is held with a slight gap between the rotor 6 and the stator 7.
The crankshaft 4 has an eccentric pin portion 4a formed at the upper end thereof. The eccentric pin portion 4a is fitted in the recessed bearing 2d of the orbiting scroll 2. The orbiting scroll 2 is caused to perform an eccentric revolving motion by the rotation of the crankshaft 4.
An oil pump 21 is fixed to the lower side of the crankshaft 4. The oil pump 21 is a positive-displacement pump, and has a function of supplying refrigerating machine oil stored in the oil reservoir 12 to the recessed bearing 2d and the bearing portion 3b through an oil circuit 22 provided in the crankshaft 4 with the rotation of the crankshaft 4.
In the shell 8, an Oldham ring 20 for preventing the rotation of the orbiting scroll 2 during the eccentric revolving motion thereof is disposed. The Oldham ring 20 is disposed between the fixed scroll 1 and the orbiting scroll 2, and serves a function of preventing the rotation of the orbiting scroll 2 while allowing for revolution.
The operation of the scroll compressor 100 will be described briefly.
When a not shown supply terminal provided in the shell 8 is energized, torque is generated in the stator 7 and the rotor 6, and the crankshaft 4 rotates. By the rotation of the crankshaft 4, the orbiting scroll 2 is caused to perform eccentric revolving motion while being prevented from rotating by the Oldham ring 20. Refrigerant suctioned through the suction pipe 5 into the shell 8 is introduced into outer peripheral ones 9 of the plurality of compression chambers 9 formed between the first scroll wrap 1b of the fixed scroll 1 and the second scroll wrap 2b of the orbiting scroll 2.
The compression chambers 9 into which gas is introduced decrease their volumes while moving from the outer periphery toward the center with the eccentric revolving motion of the orbiting scroll 2, thereby compressing refrigerant. The compressed refrigerant gas is discharged through the discharge port 1a provided to the fixed scroll 1 against the valve guard 10, and is discharged through the discharge pipe 13 to the outside of the shell 8.
The refrigeration cycle apparatus of
Next, the operation of the refrigeration cycle apparatus will be described.
Refrigerant discharged from the scroll compressor 100 flows into the radiator 51, exchanges heat with air passing through the radiator 51 to radiate heat, and flows out of the radiator 51. The expansion coefficient by throttling and flow rate of refrigerant flowing out of the radiator 51 are controlled by the expansion valve 52, and then refrigerant flows into the evaporator 53. Low-pressure two-phase refrigerant flowing into the evaporator 53 exchanges heat with air passing through the evaporator 53, then returns to the inside of the scroll compressor 100 through the suction pipe 5, and is suctioned into the compression chambers 9 again.
Here, for example, in operation in which the difference between the temperature of refrigerant suctioned into the scroll compressor 100 (hereinafter referred to as suction temperature) and the discharge temperature is large, that is, operation in which the difference between high pressure and low pressure is large (hereinafter referred to as high compression ratio operation), refrigerant discharged through the discharge pipe 13 is at a high temperature. So, by injecting liquid refrigerant taken out from the refrigerant outlet of the radiator 51 into the compression chambers 9, the discharge temperature is lowered. Specifically, after high-pressure liquid refrigerant is taken out from the radiator 51, the expansion coefficient by throttling and flow rate are controlled by the expansion valve 52 and the solenoid valve 56, and the refrigerant is decompressed to the intermediate pressure. Liquid refrigerant at the intermediate pressure enters the inside of the scroll compressor 100 through the injection pipe 15. Liquid refrigerant entering the inside of the scroll compressor 100 passes through the injection distribution channel 15a formed in the fixed scroll 1 and the injection ports 16, is injected into the compression chambers 9, and cools gas refrigerant being compressed in the compression chambers 9. Injecting liquid refrigerant at the intermediate pressure may hereinafter be referred to as intermediate injection.
In
In
In
In
In
The revolving motion of the orbiting scroll 2 further progresses, and then the scroll wraps return to the state of
In high compression ratio operation, since injection is performed, liquid refrigerant passes through the injection ports 16. However, in operation other than high compression ratio operation, since injection is stopped, liquid refrigerant does not pass through the injection ports 16, and the injection ports 16 are empty. In the present invention, carbon dioxide is used as refrigerant, and operating pressure is as high as three to four times compared to HFC refrigerant. Therefore, the pressure difference between the pressure in the injection ports 16 and the pressure in the compression chambers 9 is large. To prevent the breakage of the tip seal member 17b due to the deformation of the tip seal member 17b caused by such pressure difference, the following measures are taken.
From the graph of
From
In a scroll compressor using conventional HFC refrigerant, liquid refrigerant is injected using an intermediate injection mechanism, and gas refrigerant in the compression chambers 9 is cooled utilizing latent heat when the liquid refrigerant undergoes the phase transition from the liquid phase to the gas phase. Conventionally, since latent heat is utilized, efficient cooling of gas refrigerant is possible.
However, since supercritical refrigerant such as carbon dioxide does not undergo phase transition, heat of fusion and latent heat do not exist. As shown in
Therefore, in a refrigeration cycle apparatus that performs intermediate injection using carbon dioxide, it is desirable to control the radiator outlet temperature to 30 degrees C. or lower, by for example, controlling the opening degree of the expansion valve 52. By controlling the outlet temperature of the radiator 51 to 30 degrees C. or lower, outlet refrigerant of the radiator 51, that is, refrigerant used for injection can be made liquid refrigerant, and gas refrigerant in the compression chambers 9 can be efficiently cooled. The lower limit of the radiator outlet temperature varies depending on the heat medium that cools refrigerant in the radiator 51. When the heat medium is air, the lower limit of the radiator outlet temperature is outside air (ambient) temperature. When the heat medium is water, the lower limit of the radiator outlet temperature is higher than 0 degrees C.
As described above, when discharge temperature is high, intermediate injection is performed to lower discharge temperature. Since, in intermediate injection, intermediate pressure refrigerant is caused to flow into the compression chambers 9, the pressure rising curve when intermediate injection is performed bulges to the upper right in the figure compared to the pressure rising curve when intermediate injection is not performed. When the pressure of injection refrigerant (intermediate pressure) is higher than necessary, an excessive compression part in which the pressure in the compression chambers 9 is higher than the target discharge pressure is generated, and loss is caused. When this loss is caused, the input of the compressor increases, and COP decreases. Therefore, excessive compression is desired to be prevented. In Embodiment 1, excessive compression can be prevented by a configuration in which the injection ports 16 communicate with the discharge port 1a as described with reference to
That is, because of a configuration in which the injection ports 16 communicate with the discharge port 1a, when an excessive amount of intermediate pressure refrigerant flows in through the injection ports 16, and the pressure in the compression chambers 9 becomes the discharge pressure or higher, refrigerant in the compression chambers 9 is discharged through the discharge port 1a to the refrigerant circuit. Therefore, when performing intermediate injection, generation of an excessive compression part can be prevented, and an increase in input of the compressor can be prevented.
As described above, according to Embodiment 1, since the injection port diameter ϕinj and the tip seal width TIP have the relationship of ϕinj≤(0.95×TIP), the breakage of the tip seal member 17b can be prevented, and the reliability of the scroll compressor 100 can be ensured.
Since, in the compression process, the injection ports 16 communicate with the discharge port 1a provided in the center of the fixed scroll 1, excessive compression can be prevented.
Since each of the compression chambers 9 symmetrical with respect to the discharge port 1a is provided with one or more and the same number of injection ports 16, the pressures in the compression chambers 9 are equal. Therefore, the revolution moment acting on the orbiting scroll 2 is minimum, and the advantageous effect of improving the reliability of the Oldham ring preventing rotation can be obtained.
The scroll compressor 100 of the above-described Embodiment 1 is a scroll compressor of the so-called high-pressure shell type in which the pressure in the internal space of the shell 8 is high. In contrast, Embodiment 2 is a scroll compressor of the so-called low-pressure shell type in which the pressure in the internal space of the shell 8 is low. The advantageous effect of the scroll compressor of the low-pressure shell type is similar to that of the scroll compressor of the high-pressure shell type. The configuration characteristic of the case of the low-pressure shell type will be described below.
In the scroll compressor 100 of Embodiment 2, refrigerant gas discharged through the discharge port 1a is guided directly to the discharge pipe 13 without being supplied to the internal space of the shell 8. Therefore, the internal space of the shell 8 is at low pressure owing to suction pressure refrigerant flowing in through the suction pipe 5.
When only suction pressure refrigerant acts on the shell 8, the shell 8 is cooled by outside air (winter) or suction pressure refrigerant (summer) and heat-shrinks. On the other hand, when, during the operation of the compressor, the pressure in the compression chambers 9 becomes higher than the pressure in the injection pipe 15, high-pressure refrigerant flows back to the injection pipe 15 from the compression chambers 9, and therefore the injection pipe 15 is heated by this back-flowing high-pressure refrigerant and is thermally expanded. In this case, the injection pipe 15 is strained in the shell 8, and may break. So, in
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/066929 | 6/11/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/199281 | 12/15/2016 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4673340 | Mabe | Jun 1987 | A |
| 5722257 | Ishii | Mar 1998 | A |
| 20050147514 | Lifson et al. | Jul 2005 | A1 |
| 20100129240 | Shiibayashi | May 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| H05-296165 | Nov 1993 | JP |
| 2002-013491 | Jan 2002 | JP |
| 2012-127222 | Jul 2012 | JP |
| Entry |
|---|
| Extended EP Search Report dated Feb. 11, 2019 issued in corresponding EP patent application No. 15894966.9. |
| International Search Report of the International Searching Authority dated Aug. 18, 2015 for the corresponding international application No. PCT/JP2015/066929 (and English translation). |
| Office Action dated May 31, 2019 issued in corresponding CN patent application No. 201580080684.3 (and English translation). |
| Number | Date | Country | |
|---|---|---|---|
| 20180128270 A1 | May 2018 | US |
