Scroll compressor
The scroll compressor addresses tooth tip biting by incorporating a low-temperature refrigerant injection port and low-expansion materials to mitigate thermal expansion issues, improving operational reliability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI HEAVY IND THERMAL SYST
- Filing Date
- 2024-11-05
- Publication Date
- 2026-05-19
AI Technical Summary
The injection of a refrigerant colder than the refrigerant in the compression process in scroll compressors leads to a temperature difference causing thermal expansion differences in the scroll wrap, potentially resulting in tooth tip biting.
A scroll compressor design with a fixed end plate having an injection port for low-temperature refrigerant introduction, using materials with a low coefficient of linear expansion (10 × 10⁻⁶ /K or lower) for the fixed and orbiting scroll members, and strategically positioning the injection port to minimize thermal expansion differences.
Reduces the likelihood of tooth tip galling by minimizing thermal expansion differences in the scroll wraps, thereby enhancing the compressor's operational reliability.
Smart Images
Figure 2026081598000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a scroll compressor.
Background Art
[0002] For example, in the scroll compressor described in Patent Document 1, an injection structure for injecting a low-temperature refrigerant during the compression stroke is adopted in order to lower the discharge gas temperature.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When a refrigerant colder than the refrigerant in the compression process is injected into the compression chamber, the housing, or the suction pipe, a temperature difference occurs in the compression chamber due to the temperature drop of the scroll wrap caused by the injected refrigerant. Then, a thermal expansion difference (tooth height expansion difference) occurs in the scroll wrap, so that an event in which the tooth tip of the wrap contacts the end plate facing it (this is referred to as "tooth tip biting") may occur.
[0005] In view of such circumstances, the present disclosure has been made, and an object thereof is to provide a scroll compressor capable of reducing the possibility of tooth tip biting.
Means for Solving the Problems
[0006] In order to solve the above problems, the scroll compressor of the present disclosure adopts the following means. A scroll compressor according to one aspect of the present disclosure comprises a fixed scroll member having a spiral fixed wrap on a fixed end plate, and a spiral scroll member having a spiral spiral wrap on a spiral end plate positioned opposite the fixed end plate, wherein the spiral wrap engages with the fixed wrap to form a compression chamber for compressing a fluid, wherein the fixed end plate has an injection port for guiding a fluid at a lower temperature than the fluid undergoing compression in the compression chamber into the compression chamber, and the fixed scroll member and / or the spiral scroll member have a coefficient of linear expansion of 10 × 10 -6 It consists of materials with a temperature of / K or lower. [Effects of the Invention]
[0007] According to this disclosure, the possibility of tooth tip gnawing occurring can be reduced. [Brief explanation of the drawing]
[0008] [Figure 1] This figure shows an example of a refrigerant circuit including a scroll compressor according to one embodiment of the present disclosure. [Figure 2] This is a longitudinal cross-sectional view of a scroll compressor according to one embodiment of the present disclosure. [Figure 3] This is a plan cross-sectional view of the compression mechanism of a scroll compressor according to one embodiment of the present disclosure. [Modes for carrying out the invention]
[0009] A scroll compressor according to one embodiment of this disclosure will be described below with reference to the drawings.
[0010] [Scroll Compressor Configuration] As shown in Figure 1, the scroll compressor 11, together with the condenser 12, expansion valve 13, evaporator 14, refrigerant piping 15, etc., constitutes a refrigeration cycle 10 in which fluid is sealed. The fluid is specified as a refrigerant that exhibits a greater temperature change during the compression process than R1234yf (for example, R32).
[0011] This refrigeration cycle 10 is equipped with an injection circuit 20. The injection circuit 20 includes an injection pipe 21, a strainer 22 provided in the injection pipe 21, a valve 23, and a capillary tube 24.
[0012] The injection piping 21 connects the refrigerant piping 15, which is connected to the refrigerant outlet of the condenser 12, to the scroll compressor 11, and is configured to guide the refrigerant condensed in the condenser 12 to the scroll compressor 11 (more specifically, to the injection pipe 34 described later). The strainer 22 is a device for removing foreign matter contained in the liquid refrigerant flowing through the injection piping 21. Valve 23 is a valve for adjusting the flow rate of liquid refrigerant flowing through the injection piping 21. Examples of valve 23 include on-off valves and flow control valves. The capillary tube 24 is a device that prepares the liquid refrigerant flowing through the injection piping 21 for injection at a suitable pressure and condition.
[0013] The injection circuit 20 further includes a temperature measuring means (not shown). The temperature measuring device is an instrument for measuring the temperature of the refrigerant immediately before it flows into the scroll compressor 11. Based on the values measured by the temperature measuring device, the degree of superheating of the refrigerant immediately before it flows into the scroll compressor 11 is determined. Thermocouples are an example of a temperature measurement method. However, the degree of superheating of the refrigerant may be determined by methods other than those using thermocouples. The temperature measurement means may be provided in the injection tube 34, which will be described later.
[0014] As shown in Figure 2, the scroll compressor 11 is a sealed scroll compressor and comprises a housing 33 having a sealed space inside, a discharge cover 40 that divides the sealed space, a compression mechanism 60 that compresses the refrigerant, a drive shaft 95 that causes the orbiting scroll member 80 of the compression mechanism 60 to revolve and rotate, and an electric motor 96 that drives the drive shaft 95.
[0015] The housing 33 has an upper housing 33A, an intermediate housing 33B, and a lower housing (not shown), and forms a sealed space inside.
[0016] The upper housing 33A and the intermediate housing 33B are connected via the outer peripheral end of the discharge cover 40. Therefore, the discharge cover 40 divides the sealed space inside the housing 33 in the direction of the central axis X (the vertical direction in FIG. 2). Of the divided sealed spaces, the space formed above the discharge cover 40 is the discharge chamber 53, and the space formed below the discharge cover 40 is the suction chamber 55.
[0017] A discharge pipe 31 for discharging refrigerant from the discharge chamber 53 to the outside of the housing 33 is provided on the upper wall of the upper housing 33A. The discharge pipe 31 is connected to the refrigerant pipe 15, and is configured such that the refrigerant discharged from the discharge pipe 31 is led to the condenser 12 (see FIG. 1).
[0018] An intake pipe 32 for sucking refrigerant from the outside of the housing 33 into the suction chamber 55 is provided on the side wall of the intermediate housing 33B. The intake pipe 32 is connected to the refrigerant pipe 15, and is configured such that the refrigerant evaporated in the evaporator 14 is led to the suction chamber 55 (see FIG. 1).
[0019] A compression mechanism 60 for compressing the refrigerant, a drive shaft 95, an electric motor 96, and a support member 97 for pivotally supporting the drive shaft 95 are provided in the suction chamber 55.
[0020] The compression mechanism 60 has a fixed scroll member 70 provided with a spiral fixed wrap 75 on a fixed end plate 71 and a revolving scroll member 80 provided with a spiral revolving wrap 85 on a revolving end plate 81. In the fixed scroll member 70 and the orbiting scroll member 80, the fixed wrap 75 and the orbiting wrap 85 interlock with each other to form a compression chamber 61. The tooth height of the fixed lap 75 and the swivel lap 85 is specified to be, for example, 15 mm or more. A lap gap is set between the tooth tip of the fixed lap 75 and the tooth root of the swivel end plate 81, and between the tooth tip of the swivel lap 85 and the tooth root of the fixed end plate 71, taking into account the thermal expansion of each lap. However, the lap gap in the area facing the injection port 73 (openings 73a, 73b), which will be described later, may be set larger than the lap gap in other areas.
[0021] The fixed scroll member 70 and / or the orbiting scroll member 80 have a coefficient of linear expansion of 10 × 10 -6 Materials with a temperature of / K or less, preferably 5 × 10 -6 It is made of a material with a coefficient of thermal expansion of 10°C or less. The lower limit of the coefficient of thermal expansion is not particularly limited, but as an example, it is 0.7 × 10°C. -6 It is designated as / K. An example of such a material is low thermal expansion cast iron in which carbon (C), silicon (Si), nickel (Ni), and antimony (Sb) are blended in optimal ratios. The portion formed from this material is the base material of the fixed scroll member 70 and / or the orbiting scroll member 80. For example, the coating applied to the fixed scroll member 70 and / or the orbiting scroll member 80 may be made of a different material.
[0022] The fixed scroll member 70 is fixed to the support member 97 by a fixing portion 74 formed on the outer peripheral end of the fixed end plate 71. Since the support member 97 is fixed to the intermediate housing 33B, the fixed scroll member 70 is fixed to the intermediate housing 33B via the support member 97.
[0023] The orbiting scroll member 80 is configured to revolve and orbit around the central axis X of the fixed scroll member 70 by means of a drive shaft 95 and an anti-rotation mechanism (e.g., an Oldham link).
[0024] A discharge cover 40 is positioned above the fixed scroll member 70 (on the back side of the fixed end plate 71), and together with the back surface of the fixed end plate 71, it forms a back pressure chamber 54 and an injection refrigerant flow path 56. The back pressure chamber 54 is a space formed approximately in the center in the radial direction. On the other hand, the injection refrigerant flow path 56 is a space (flow path) formed radially outside the back pressure chamber 54 and does not communicate with the back pressure chamber 54.
[0025] The fixed end plate 71 has a discharge port 72 that connects the compression chamber 61 and the back pressure chamber 54. The discharge cover 40 also has a discharge port 41 (different from the discharge port 72 on the fixed end plate 71) that connects the back pressure chamber 54 and the discharge chamber 53. In other words, the compression chamber 61 and the discharge chamber 53 are connected via the discharge port 72, the back pressure chamber 54, and the discharge port 41.
[0026] In the back pressure chamber 54, a reed valve 92 and a retainer 93 that restricts the range of motion of the reed valve 92 are provided at the outlet of the discharge port 72.
[0027] The fixed end plate 71 is further provided with at least one injection port 73 that connects the compression chamber 61 and the injection refrigerant flow path 56. An injection pipe 34 for guiding refrigerant from the injection piping 21 is provided on the upper wall of the upper housing 33A. The injection pipe 34 is connected to the injection refrigerant flow path 56 via a connecting pipe 35 attached to the discharge cover 40. In other words, the flow path in the injection pipe 34 and the compression chamber 61 are in communication via the flow path in the connecting pipe 35, the injection refrigerant flow path 56, and the injection port 73.
[0028] As shown in Figure 3, the position of the injection port 73 (more precisely, the positions of the openings 73a and 73b of the injection port 73 facing the compression chamber 61) is set to a predetermined location. The designated location is within 180 degrees from the position where the compression chamber 61 is closed by the engagement of the end of the fixed wrap 75 of the fixed scroll member 70 and the end of the orbiting wrap 85 of the orbiting scroll member 80. In the case of Figure 3, an opening 73a of the injection port 73 is provided at a position where communication to the compression chamber 61 begins when the chamber is closed at the closing start position P1 (this may be within a further 180-degree range in the orbital angle), and an opening 73b of another injection port 73 is provided at a position where communication to the compression chamber 61 begins when the chamber is closed at the closing start position P2 (this may be within a further 180-degree range in the orbital angle). Furthermore, the closing start position P1 is also the position where the inner surface of the fixed wrap 75 and the outer surface of the swivel wrap 85 begin to come into contact. Therefore, the opening 73a faces the compression chamber 61 formed between the inner surface of the fixed wrap 75 and the outer surface of the swivel wrap 85. On the other hand, the closing start position P2 is also the position where the inner surface of the swivel wrap 85 and the outer surface of the fixed wrap 75 begin to come into contact. Therefore, the opening 73b faces the compression chamber 61 formed between the inner surface of the swivel wrap 85 and the outer surface of the fixed wrap 75.
[0029] [Refrigerant flow] In the scroll compressor 11 configured as described above, the refrigerant flows as follows. In other words, the refrigerant evaporated in the evaporator 14 (see Figure 1) is guided through the refrigerant piping 15 to the suction chamber 55 of the scroll compressor 11 via the suction pipe 32. Here, it is preferable that the superheating degree of the refrigerant at the outlet of the suction pipe 32 is 30 degrees or less.
[0030] As shown in Figure 2, the refrigerant introduced into the intake chamber 55 is taken into the compression chamber 61 from around the compression mechanism 60 (compression chamber 61). The refrigerant taken into the compression chamber 61 is compressed in the compression chamber 61, whose volume changes due to the orbital motion of the orbiting scroll member 80, and is then introduced into the back pressure chamber 54 through the discharge port 72 formed in the central part of the fixed end plate 71. Here, it is preferable that the degree of superheating of the refrigerant at the inlet of the compression chamber 61 is 50 degrees or less.
[0031] The refrigerant, guided into the back pressure chamber 54, is then guided to the discharge chamber 53 via a discharge port 41 formed in the discharge cover 40.
[0032] The refrigerant guided into the discharge chamber 53 is then led from the discharge pipe 31 to the condenser 12 (see Figure 1) via the refrigerant piping 15 connected to the discharge pipe 31.
[0033] As shown in Figure 1, the refrigerant introduced into the condenser 12 is condensed by heat exchange, and some of the liquid refrigerant is introduced into the injection piping 21, while the remaining refrigerant is introduced into the expansion valve 13 via the refrigerant piping 15.
[0034] The refrigerant guided to the expansion valve 13 is expanded (pressure reduced) and then guided to the evaporator 14. The same cycle repeats thereafter.
[0035] Meanwhile, the liquid refrigerant guided into the injection piping 21 is led to the injection tube 34 provided in the scroll compressor 11 via the strainer 22, valve 23, and capillary tube 24.
[0036] As shown in Figure 2, the refrigerant guided into the injection tube 34 is led to the compression chamber 61 via the injection refrigerant flow path 56 and the injection port 73, where it merges with the refrigerant undergoing compression. Here, the temperature of the refrigerant introduced into the compression chamber 61 is lower than the temperature of the refrigerant undergoing compression in the compression chamber 61. While the refrigerant is initially in the form of wet vapor immediately after flowing out of the capillary tube 24, it may be heated during the process leading to the compression chamber 61, resulting in superheated vapor just before it enters the chamber. If the refrigerant is superheated vapor, its degree of superheating is preferably 10 degrees or less.
[0037] [effect] The scroll compressor according to this embodiment provides the following effects.
[0038] The fixed end plate 71 has an injection port 73 formed therein for guiding a refrigerant at a lower temperature than the refrigerant undergoing compression in the compression chamber 61 into the compression chamber 61, and the fixed scroll member 70 and / or the orbiting scroll member 80 have a coefficient of linear expansion of 10 × 10 -6 Since it is made of a material with a temperature of 0.5°C or lower, the difference in thermal expansion (difference in tooth height expansion) between each wrap 75 and 85, caused by the temperature difference in the compression chamber resulting from introducing a low-temperature refrigerant, is smaller than the difference in thermal expansion when using general materials, thus reducing the possibility of tooth tip galling caused by the difference in thermal expansion.
[0039] Since the degree of superheating of the fluid introduced into the compression chamber 61 via the injection port 73 is set to 10 degrees or less, in this embodiment, where a low-temperature refrigerant is introduced into the compression chamber 61 and the temperature difference within the compression chamber 61 tends to be large, it is expected that the possibility of tooth tip galling caused by thermal expansion differences will be reduced.
[0040] Since the injection port 73 is formed within a range of 180 degrees from the positions P1 and P2 where the compression chamber 61 begins to close, in this embodiment, where the outer periphery of the compression chamber 61 tends to become colder and the temperature difference between the outer periphery and the center of the compression chamber 61 tends to become large, it is expected that the possibility of tooth tip galling caused by thermal expansion differences will be reduced.
[0041] Since the superheating degree of the refrigerant at the outlet of the suction pipe 32 is set to 30 degrees or less, or the superheating degree of the refrigerant at the inlet of the compression chamber 61 is set to 50 degrees or less, in this embodiment, where a temperature difference is likely to occur between the refrigerant introduced into the compression chamber 61 via the injection port 73, it is expected that the possibility of tooth tip galling caused by thermal expansion differences will be reduced.
[0042] Since the refrigerant undergoes a greater temperature change during the compression process in the compression chamber 61 than R1234yf, in this embodiment, where the temperature difference between the outer periphery and the center of the compression chamber 61 tends to be large, it is expected to have the effect of reducing the possibility of tooth tip galling caused by thermal expansion differences.
[0043] In this embodiment, where a temperature difference is likely to occur between the refrigerant introduced into the compression chamber 61 via the injection port 73, the difference in thermal expansion is large in the area facing the injection port 73 (openings 73a, 73b). Therefore, by increasing the overlap gap in that area, it is expected that the possibility of tooth tip galling caused by the difference in thermal expansion in that area can be reduced.
[0044] [Differentiation] In the embodiment described above, a low-temperature refrigerant was injected into the compression chamber 61 through an injection port 73 formed in the fixed end plate 71. However, the location where the low-temperature refrigerant is introduced is not limited to the injection port 73 formed in the fixed end plate 71, but can be any location where the low-temperature refrigerant is ultimately introduced into the compression chamber 61. For example, an injection port may be formed in the suction pipe 32 or the housing 33 to inject a low-temperature refrigerant into the inside of the suction pipe 32 or the inside of the housing 33 (for example, the suction chamber 55).
[0045] [Note] As described above, the scroll compressor according to one embodiment of the present disclosure can be understood, for example, as follows.
[0046] A scroll compressor (11) according to a first aspect of the present disclosure comprises a fixed scroll member (70) having a spiral fixed wrap (75) on a fixed end plate (71), and a spiral scroll member (80) having a spiral spiral wrap (85) on a spiral end plate (81) arranged opposite to the fixed end plate, the spiral wrap meshing with the fixed wrap to form a compression chamber (61) for compressing a fluid, and an injection port (73) for introducing a fluid at a lower temperature than the fluid being compressed into the compression chamber, and the fixed scroll member and / or the spiral scroll member having a coefficient of linear expansion of 10 × 10 -6 It consists of materials with a temperature of / K or lower.
[0047] An injection port is provided in the compression chamber to introduce a fluid at a lower temperature than the fluid undergoing compression into the compression chamber, and the fixed scroll member and / or orbiting scroll member have a coefficient of linear expansion of 10 × 10 -6 Since it is made of a material with a temperature of 0.5°C or lower, the difference in thermal expansion (difference in tooth height expansion) of each wrap caused by the temperature difference in the compression chamber resulting from introducing a low-temperature fluid is smaller than the difference in thermal expansion when using general materials, thus reducing the possibility of tooth tip galling caused by the difference in thermal expansion.
[0048] In the scroll compressor according to a second aspect of this disclosure, in the first aspect, the degree of superheating of the fluid introduced into the compression chamber via the injection port is 10 degrees or less.
[0049] Since the superheating of the fluid introduced into the compression chamber via the injection port is set to 10 degrees or less, in this embodiment, where a low-temperature fluid is introduced into the compression chamber and the temperature difference within the compression chamber tends to be large, it is expected that the possibility of tooth tip galling caused by thermal expansion differences will be reduced.
[0050] In the scroll compressor according to the third aspect of this disclosure, in the first or second aspect, the injection port is formed in the fixed end plate and is located within a range of 180 degrees from the position (P1, P2) where the closure of the compression chamber is initiated.
[0051] Since the injection port is formed in the fixed end plate and positioned within 180 degrees from the position where the compression chamber is closed, in this embodiment, where the outer periphery of the compression chamber tends to become colder and the temperature difference between the outer periphery and the center of the compression chamber tends to be large, it is expected to have the effect of reducing the possibility of tooth tip galling caused by thermal expansion differences.
[0052] A scroll compressor according to a fourth aspect of the present disclosure, in any of the first to third aspects, comprises a housing (33) for housing the fixed scroll member and the orbiting scroll member, and a suction pipe (32) for introducing fluid into the housing, wherein the degree of superheating of the fluid at the outlet of the suction pipe is 30 degrees or less, or the degree of superheating of the fluid at the inlet of the compression chamber is 50 degrees or less.
[0053] Since the superheating of the fluid at the outlet of the suction pipe is set to 30 degrees or less, or the superheating of the fluid at the inlet of the compression chamber is set to 50 degrees or less, in this embodiment, where a temperature difference is likely to occur between the fluid introduced into the compression chamber via the injection port, it is expected that the possibility of tooth tip galling caused by thermal expansion differences will be reduced.
[0054] In the scroll compressor according to the fifth aspect of this disclosure, in any of the first to fourth aspects, the fluid is a refrigerant.
[0055] Since the fluid is a refrigerant, a scroll compressor can be used to compress the refrigerant.
[0056] In the scroll compressor according to the sixth aspect of this disclosure, in the fifth aspect, the refrigerant is such that the temperature change during the compression process in the compression chamber is greater than that of R1234yf.
[0057] Since the refrigerant is known to have a greater temperature change during the compression process in the compression chamber than R1234yf, in this embodiment, where the temperature difference between the outer periphery and the center of the compression chamber tends to be large, it is expected to have the effect of reducing the possibility of tooth tip galling caused by thermal expansion differences.
[0058] In the scroll compressor according to the seventh aspect of this disclosure, in any of the first to sixth aspects, the overlap gap in the area facing the injection port is larger than the overlap gap in the other areas.
[0059] In this embodiment, where a temperature difference is likely to occur between the fluid introduced into the compression chamber via the injection port, the difference in thermal expansion is large in the area facing the injection port. Therefore, by increasing the overlap gap in that area, it is expected that the possibility of tooth tip galling caused by the difference in thermal expansion in that area can be reduced. [Explanation of Symbols]
[0060] 10 Refrigeration Cycle 11 Scroll Compressor 12 Condenser 13 Expansion valve 14 Evaporator 15 Refrigerant piping 20 Injection Circuits 21 Injection Piping 22 Strainer 23 valves 24 Capillary tubes 31 Discharge pipe 32 Suction pipe 33 Housing 33A Upper Housing (Housing) 33B Intermediate Housing (Housing) 34 Injection tubes 35 connecting pipes 40 Discharge Cover 41 Discharge Ports 53 Discharge Chamber 54 Back pressure chamber 55 Suction chamber 56 Injection Refrigerant Flow Path 60 Compression mechanism 61 Compression Chamber 70 Fixed scroll member 71 Fixed end plate 72 Discharge Ports 73 Injection Ports 74 Fixed part 75 Fixing Wrap 80 Swivel Scroll Member 81 Swivel end plate 85 Turning Lap 92 Reed valve 93 Retainer 95 Drive shaft 96 Electric motor 97 Support Members
Claims
1. A fixed scroll member having a spiral-shaped fixing wrap on a fixed end plate, A spiral scroll member is provided with a spiral-shaped spiral wrap on a spiral end plate positioned opposite the fixed end plate, and the spiral wrap engages with the fixed wrap to form a compression chamber that compresses the fluid. Equipped with, An injection port is provided in the compression chamber for introducing a fluid at a lower temperature than the fluid undergoing compression into the compression chamber. The fixed scroll member and / or the orbiting scroll member have a coefficient of linear expansion of 10 × 10 －６ Made from materials with a K rating of / or lower. Scroll compressor.
2. The degree of superheating of the fluid introduced into the compression chamber via the injection port is set to 10 degrees or less. The scroll compressor according to claim 1.
3. The aforementioned injection port is Formed on the aforementioned fixed end plate, It is located within a range of 180 degrees from the position where the closure of the compression chamber began. The scroll compressor according to claim 1.
4. A housing that accommodates the fixed scroll member and the orbiting scroll member, An intake pipe for guiding fluid into the interior of the housing, Equipped with, The degree of superheating of the fluid at the outlet of the suction pipe is set to 30 degrees or less, or The degree of superheating of the fluid at the inlet of the compression chamber is set to 50 degrees or less. The scroll compressor according to claim 2.
5. The aforementioned fluid is designated as a refrigerant. A scroll compressor according to any one of claims 1 to 4.
6. The aforementioned refrigerant is characterized by a greater temperature change during the compression process in the compression chamber compared to R1234yf. The scroll compressor according to claim 5.
7. The overlap gap in the area facing the injection port is larger than the overlap gap in other areas. The scroll compressor according to claim 3.