JP7138807B2 - scroll compressor - Google Patents

Description

TECHNICAL FIELD The present invention relates to scroll compressors that are mainly mounted on refrigerators, air conditioners, or water heaters.

In a scroll compressor, spiral bodies of a fixed scroll and an orbiting scroll are combined to form a compression chamber, and the orbiting scroll is caused to orbit to compress refrigerant in the compression chamber. Conventionally, there has been a scroll compressor in which the heights of the spiral bodies of the fixed scroll and the orbiting scroll are constant, and the refrigerant is two-dimensionally compressed from the outer peripheral portion to the central portion. On the other hand, in recent years, stepped portions are provided at intervals in the spiral direction on the crest and bottom surfaces of the spirals of the fixed scroll and the orbiting scroll, respectively, and the stepped portions serve as borders on the outer periphery of the spiral. There is a scroll compressor (see, for example, Patent Document 1) in which the height of is higher than the height of the inner peripheral side. This type of stepped scroll compressor enables three-dimensional compression that compresses not only in the circumferential direction but also in the vertical direction, so it is possible to increase the displacement without increasing the outer diameter of the scroll. can be increased.

Japanese Patent No. 6180860

In scroll compressors, from the viewpoint of performance improvement, it is a task to reduce refrigerant leakage between compression chambers. In order to reduce the refrigerant leakage between the compression chambers, it is effective to increase the number of compression chambers by increasing the number of turns of the spiral body, thereby reducing the differential pressure between the compression chambers.

A refrigerant with a large polytropic index, such as carbon dioxide, has a higher rate of increase in pressure with respect to a reduction in compression chamber volume than a refrigerant with a small polytropic index. Therefore, when a single carbon dioxide or a mixed refrigerant containing carbon dioxide is used as a refrigerant for a scroll compressor that performs two-dimensional compression, the compression volume decreases linearly in the two-dimensional compression, so the pressure in the compression chamber is It rises to the target high pressure with a small number of rotations. Therefore, the number of turns of the spiral body cannot be increased.

Moreover, Patent Document 1 uses three-dimensional compression, which has a higher compression rate than two-dimensional compression. Therefore, when carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used, the pressure at the center of the scroll becomes too high. For this reason, the number of turns of the spiral body cannot be increased as in the case of two-dimensional compression, and there is a problem that it is difficult to suppress refrigerant leakage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is capable of reducing refrigerant leakage between compression chambers even when using carbon dioxide alone or a mixed refrigerant containing carbon dioxide as a refrigerant. An object of the present invention is to provide a scroll compressor capable of suppressing deterioration in performance.

A scroll compressor according to the present invention has a fixed scroll having a fixed bed plate and a fixed spiral body formed on the fixed bed plate, a swing bed plate and a swing spiral body formed on the swing bed plate, an oscillating scroll arranged so as to face the oscillating bedplate to the fixed bedplate, and the oscillating scroll being combined with the fixed spiral body to form a compression chamber, wherein the fixed bedplate and the oscillating bedplate The distance between the base plates , which is the distance between the is provided with a spiral side stepped portion so that the tooth height, which is the height of each, increases stepwise from the outer peripheral portion to the central portion. A base plate side stepped portion is provided corresponding to the spiral side stepped portion of the spiral body, and the plate thickness is formed to be gradually reduced from the outer peripheral portion to the central portion .

In the scroll compressor according to the present invention, the distance between the base plates, which is the distance between the fixed base plate and the oscillating base plate, is stepped from the outer peripheral portion to the central portion of the fixed spiral body and the oscillating spiral body. It has a structure that grows to Therefore, since the volume reduction rate of the compression chamber can be reduced, the rate at which the pressure in the compression chamber rises can be reduced even when carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used as the refrigerant. Therefore, the number of compression chambers can be increased by increasing the number of turns of the spiral body. As a result, the differential pressure between the compression chambers can be reduced, and deterioration in performance due to refrigerant leakage can be suppressed.

1 is a schematic cross-sectional view of a scroll compressor according to Embodiment 1; FIG. 2 is a schematic cross-sectional view of a compression mechanism portion of the scroll compressor according to Embodiment 1; FIG. FIG. 2 is a view of a fixed scroll and an orbiting scroll of the scroll compressor according to Embodiment 1 as viewed from the orbiting scroll side; FIG. 4 is an explanatory diagram of the tooth height of the spiral body of the scroll compressor according to Embodiment 1; 4 is an explanatory diagram of the plate thickness of the base plate of the scroll compressor according to Embodiment 1. FIG. 4 is a change diagram of the compression chamber volume with respect to the rotation phase of the oscillating spiral body in the scroll compressor according to Embodiment 1. FIG. 4 is a change diagram of compression chamber pressure with respect to the rotation phase of the oscillating spiral body in the scroll compressor according to Embodiment 1. FIG. FIG. 8 is an enlarged view of a compression chamber of a scroll compressor according to Embodiment 2; FIG. 10 is a change diagram of the compression chamber volume with respect to the rotation phase of the oscillating spiral body in the scroll compressor according to Embodiment 2; FIG. 10 is a change diagram of the compression chamber pressure with respect to the rotation phase of the oscillating spiral body in the scroll compressor according to Embodiment 2;

A scroll compressor according to an embodiment of the present invention will be described below with reference to the drawings. Here, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and are common throughout the embodiments described below. The forms of the constituent elements shown in the entire specification are merely examples, and are not limited to the forms described in the specification. Moreover, the level of the pressure is not determined in relation to an absolute value, but relatively determined by the state or operation of the system or device.

Embodiment 1.
Embodiment 1 will be described below with reference to FIGS. 1 to 7. FIG.

FIG. 1 is a schematic cross-sectional view of a scroll compressor according to Embodiment 1. FIG.
This scroll compressor has a function of sucking refrigerant, compressing it, and discharging it in a state of high temperature and high pressure. The scroll compressor has a configuration in which a compression mechanism section 36, a drive mechanism section 37, and other components are housed inside a shell 11, which is a closed container forming an outer shell. As shown in FIG. 1 , within the shell 11 , the drive mechanism section 37 is arranged on the lower side, and the compression mechanism section 36 is arranged on the upper side. An oil reservoir 21 is provided below the shell 11 .

A suction pipe 8 for sucking the refrigerant and a discharge pipe 9 for discharging the refrigerant are connected to the shell 11 . The interior of the shell 11 forms a low-pressure space 23 due to the refrigerant sucked from the suction pipe 8 .

The compression mechanism 36 has a function of compressing the refrigerant sucked from the suction pipe 8 and discharging the compressed refrigerant to the high-pressure space 24 formed above in the shell 11 . This high-pressure refrigerant is discharged from the discharge pipe 9 to the outside of the scroll compressor. The drive mechanism portion 37 functions to drive the orbiting scroll 2 that constitutes the compression mechanism portion 36 . That is, the drive mechanism 37 drives the orbiting scroll 2 via the rotating shaft 7 , thereby compressing the refrigerant in the compression mechanism 36 . As the refrigerant compressed by the compression mechanism 36, carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used.

A frame 3 and a sub-frame 4 are arranged inside the shell 11 so as to face each other with the drive mechanism portion 37 interposed therebetween. The frame 3 is arranged above the drive mechanism portion 37 and positioned between the drive mechanism portion 37 and the compression mechanism portion 36 . The subframe 4 is positioned below the drive mechanism portion 37 . The frame 3 and subframe 4 are fixed to the inner peripheral surface of the shell 11 by shrink fitting, welding, or the like.

A through hole is formed in the central portion of the frame 3, and a bearing portion 3a is provided in this through hole. The frame 3 supports the orbiting scroll 2 and rotatably supports the rotating shaft 7 with the bearing portion 3a. The bearing portion 3a is composed of, for example, a sliding bearing. A through hole for supporting the rotating shaft 7 is formed in the central portion of the sub-frame 4, and a bearing portion 4a is provided in this through hole. The subframe 4 rotatably supports the rotating shaft 7 with the bearing portion 4a. The bearing portion 4a is configured by, for example, a rolling bearing.

The compression mechanism section 36 includes a fixed scroll 1 and an orbiting scroll 2 . As shown in FIG. 1, the orbiting scroll 2 is arranged on the lower side and the fixed scroll 1 is arranged on the upper side. The fixed scroll 1 has a fixed base plate 1c and a fixed spiral body 1b, which is a spiral projection formed on one surface of the fixed base plate 1c. The oscillating scroll 2 has an oscillating bed plate 2c and an oscillating spiral body 2b, which is a spiral-shaped projection formed on one surface of the oscillating bed plate 2c. The fixed scroll 1 and the orbiting scroll 2 are mounted in the shell 11 with the fixed spiral body 1b and the orbiting scroll body 2b meshing with each other. A compression chamber 12 is formed between the stationary spiral body 1b and the oscillating spiral body 2b, the volume of which decreases from the radially outer side to the radially inner side.

A fixed scroll 1 is fixed within a shell 11 via a frame 3 . A discharge port 1a is formed in the central portion of the fixed scroll 1 to discharge compressed and high-pressure refrigerant. At the outlet opening of the discharge port 1a, a valve 15 made of a leaf spring is arranged to cover the outlet opening and prevent the refrigerant from flowing backward. A valve retainer 14 for limiting the amount of lift of the valve 15 is provided on one end side of the valve 15 . That is, when the refrigerant is compressed to a high pressure in the compression chamber 12, the valve 15 is lifted against its elastic force, and the compressed refrigerant is discharged into the high pressure space 24 from the discharge port 1a.

A hollow cylindrical boss portion 2d is formed at the center of the surface of the orbiting scroll 2 opposite to the surface on which the orbiting spiral body 2b is formed. The boss portion 2d is provided with a swing bearing portion 2e that receives the driving force from the rotary shaft 7. As shown in FIG. The eccentric portion 7a of the rotary shaft 7 is inserted into the swing bearing portion 2e with a slight gap. The orbiting scroll 2 eccentrically orbits with respect to the fixed scroll 1 as the rotating shaft 7 rotates. A surface of the orbiting scroll 2 opposite to the surface on which the orbiting spiral body 2b is formed is axially supported by a thrust bearing portion 3b provided on the frame 3. As shown in FIG.

Hereinafter, the fixed spiral body 1b and the oscillating spiral body 2b are collectively referred to as spiral bodies when not distinguished, and the fixed base plate 1c and the oscillating base plate 2c are collectively referred to as base plates when not distinguished.

The drive mechanism portion 37 is at least composed of the stator 19 , the rotor 20 , and the rotating shaft 7 which is housed vertically in the shell 11 . The outer peripheral surface of the stator 19 is fixed and held inside the shell 11 by shrink fitting or the like. The stator 19 has a function of rotationally driving the rotor 20 when energized. The rotor 20 is rotatably arranged on the inner peripheral surface side of the stator 19 and fixed to the outer periphery of the rotating shaft 7 . The rotor 20 has a permanent magnet inside and is held with a small gap from the stator 19 . The rotor 20 has a function of being rotationally driven by energization of the stator 19 to rotate the rotating shaft 7 .

The rotating shaft 7 rotates with the rotation of the rotor 20 and drives the orbiting scroll 2 to rotate. The rotating shaft 7 is rotatable with a bearing 3a located at the center of the frame 3 on the upper side and a bearing 4a located at the center of the sub-frame 4 fixedly arranged below the shell 11 on the lower side. Supported. An eccentric portion 7a is provided at the upper end portion of the rotary shaft 7 so that the oscillating scroll 2 can be rotated while being eccentric.

An oil pump 22 is fixed to the lower side of the rotating shaft 7 . The oil pump 22 is a positive displacement pump. As the rotary shaft 7 rotates, the oil pump 22 pumps the refrigerating machine oil held in the oil reservoir 21 through an oil circuit (not shown) provided inside the rotary shaft 7 to the swing bearing portion 2e, the bearing portion 3a, and the thrust shaft. It fulfills the function of supplying to the bearing portion 3b and the bearing portion 4a.

An Oldham ring 25 is arranged in the shell 11 to prevent the orbiting scroll 2 from rotating during the eccentric orbiting motion. The Oldham ring 25 is arranged, for example, between the orbiting scroll 2 and the frame 3, and functions to prevent the orbiting scroll 2 from rotating on its axis and to allow the orbiting movement. The Oldham ring 25 may be arranged between the orbiting scroll 2 and the fixed scroll 1 .

Here, the operation of the compressor will be briefly described.
When a power supply terminal (not shown) provided on the shell 11 is energized, torque is generated in the stator 19 and the rotor 20, and the rotating shaft 7 rotates. Due to the rotation of the rotary shaft 7, the orbiting scroll 2 is restricted from rotating by the Oldham's ring 25 and performs an eccentric orbiting motion. Refrigerant sucked into the shell 11 from the suction pipe 8 passes through the outer peripheral portion of a plurality of compression chambers 12 formed between the fixed spiral body 1b of the fixed scroll 1 and the orbiting spiral body 2b of the orbiting scroll 2. is taken into the compression chamber 12 of the

As the orbiting scroll 2 eccentrically revolves, the compression chamber 12 that has taken in the gas reduces its volume while moving from the outer periphery toward the center, thereby compressing the refrigerant. The gaseous refrigerant compressed in the compression chamber 12 is discharged from the discharge port 1a provided in the fixed scroll 1 against the valve 15 into the high-pressure space 24, and discharged from the discharge pipe 9 to the outside of the shell 11. The amount of deformation of the valve 15 is regulated by a valve guard 14 so that the valve 15 is not deformed more than necessary, thereby preventing the valve 15 from being damaged.

2 is a schematic cross-sectional view of a compression mechanism portion of the scroll compressor according to Embodiment 1. FIG. FIG. 3 is a view of the fixed scroll and the orbiting scroll of the scroll compressor according to Embodiment 1 as viewed from the orbiting scroll side.

In the compression mechanism portion 36 of Embodiment 1, the distance between the fixed base plate 1c and the rocking base plate 2c (hereinafter referred to as the base plate distance) increases from the outer periphery toward the center of the spiral body. , L3, L2, and L1, as shown in FIG. As a specific structure, the spiral body and the base plate are each provided with stepped portions spaced apart in the spiral direction. In FIG. 3, reference numeral 40 denotes a spiral-side stepped portion provided on the rocking spiral body 2b, and reference numeral 41 denotes a bed-plate-side stepped portion provided on the rocking bedplate 2c. Further, reference numeral 50 shown in FIG. 3 will be described later. The details of this stepped structure will be described below with reference to FIGS. 4 and 5. FIG.

FIG. 4 is an explanatory diagram of the tooth height of the spiral body of the scroll compressor according to Embodiment 1, and is a view of the spiral body developed in the spiral direction. In FIG. 4, the horizontal axis is the extension angle [°], and the vertical axis is the tooth height [mm]. FIG. 5 is an explanatory diagram of the plate thickness of the base plate of the scroll compressor according to Embodiment 1, and is a diagram showing the plate thickness of the base plate at the same expansion angle corresponding to the developed view of FIG. 4 . . In FIG. 5, the horizontal axis is the extension angle [°], and the vertical axis is the plate thickness [mm] of the base plate.

As shown in FIG. 4, the tooth height, which is the height of the spiral body, varies from the winding end side of the extension angle θ3 to the winding start side of the extension angle θ0. It increases stepwise in the order of θ1. Specifically, the spiral body has a spiral-side stepped portion 40 such that the tooth height increases stepwise from the outer peripheral portion to the central portion.

Further, as shown in FIG. 5, the plate thickness of the base plate varies from the winding end side of the extension angle θ3 to the winding start side of the extension angle θ0 to the extension angle θ3, the extension angle θ2, and the extension angle θ1. progressively thinner. Specifically, the base plate is provided with a base plate-side stepped portion 41 so that the thickness of the plate decreases stepwise from the outer peripheral portion to the central portion. Although the number of stages is shown here as an example of three, the number of stages is not limited to this, and may be any number of stages.

By providing both the fixed scroll 1 and the orbiting scroll 2 with the above structure, a stepped structure is formed in which the distance between the base plates increases from the outer peripheral portion toward the central portion of the spiral body. That is, the extension angle range of θ0 to θ1 constitutes the portion of the base plate distance L1, and the extension angle range of θ1 to θ2 constitutes the portion of the base plate distance L2, and the extension angle range of θ2 to θ3. In the corner range, the portion of the distance L3 between the base plates is configured. In Embodiment 1, the extension angle θ1, the extension angle θ2, and the extension angle θ3 are not limited, and may be appropriately set according to the coolant to be used.

The relationship between the tooth thickness of the fixed spiral body 1b and the tooth thickness of the oscillating spiral body 2b may be the same if the spiral bodies are made of the same material, or if the materials are different, the one with the lower material strength is thicker. You can For example, if the material of the fixed spiral body 1b is iron-based casting such as FCD450, and the material of the swinging spiral body 2b is an aluminum forged product, the aluminum forged product has a lower tensile strength. Therefore, the tooth thickness of the oscillating spiral body 2b having a low tensile strength may be made thicker than the tooth thickness of the fixed spiral body 1b.

FIG. 6 is a change diagram of the compression chamber volume with respect to the rotational phase of the oscillating spiral body in the scroll compressor according to Embodiment 1. FIG. The horizontal axis is the rotational phase [°] of the swinging spiral body 2b, and the vertical axis is the compression chamber volume [cc]. In FIG. 6, the solid line indicates the first embodiment. A dashed-dotted line indicates a case without a stepped structure as a comparative example. FIG. 6 shows the relationship between the rotation phase and the compression chamber volume in the process in which the compression chamber 12 moves while reducing the compression chamber volume from the outer peripheral portion toward the central portion as the eccentric orbital motion of the oscillating spiral body 2b moves. is shown. In FIG. 6, the first stage refers to the stepped portion between the baseplate distance L3 and the baseplate distance L2, and the second stage refers to the baseplate distance L2 and the baseplate distance L1. It refers to the multi-layered part between

In the comparative example, the operation is such that the compression chamber volume decreases linearly. On the other hand, in the first embodiment, the compression chamber volume decreases until the compression chamber 12 reaches the first stage, as in the comparative example. Compression chamber volume increases by increasing from L3 to L2. Then, the compression chamber volume decreases again from the increased compression chamber volume, and when the compression chamber 12 reaches the second stage, the distance between the base plates increases from L2 to L1, and the compression chamber volume increases again. do. After that, the compression chamber volume is reduced in the same manner.

As described above, in the first embodiment, the volume of the compression chamber temporarily increases every time the compression chamber 12 reaches the stepped portion. For this reason, the reduction amount of the compression chamber volume with respect to the increase in the rotational phase, that is, the volume reduction ratio is smaller than in the comparative example. 6, with respect to an increase in rotational phase from θa to θb, in the comparative example, the compression chamber volume decreases by Va+Vb, whereas in the first embodiment, it is Va, and the volume reduction ratio is lower than that in the comparative example. It is small compared to Therefore, in the first embodiment, compression is performed more slowly than in the comparative example. A change in compression chamber pressure will be described below with reference to FIG.

FIG. 7 is a change diagram of the compression chamber pressure with respect to the rotation phase of the oscillating spiral body in the scroll compressor according to Embodiment 1. FIG. The horizontal axis represents the rotational phase [°] of the oscillating spiral body 2b, and the vertical axis represents the compression chamber pressure [MPaG]. In FIG. 7, the solid line indicates the first embodiment. A dashed-dotted line indicates a case without a stepped structure as a comparative example.

Comparing the first embodiment with the comparative example, the compression chamber pressure similarly rises until the compression chamber 12 reaches the first stage. In the comparative example, the compression chamber pressure rises as the rotation phase progresses after that as well. On the other hand, in the first embodiment, when the compression chamber 12 reaches the first stage, the volume of the compression chamber increases as described above, so that the refrigerant in the compression chamber 12 expands and the compression chamber pressure decreases. Thereafter, in Embodiment 1, the compression chamber pressure increases again, and when the compression chamber 12 reaches the second stage, the compression chamber pressure decreases again. Then, the compression chamber pressure rises to the high pressure Pd.

As described above, in the first embodiment, the pressure in the compression chamber is temporarily lowered every time the compression chamber 12 reaches the stepped portion. Therefore, in the first embodiment, it is necessary to rotate the orbiting spiral body 2b more than in the comparative example until the compression chamber pressure reaches the target high pressure Pd. Referring to FIG. 7, in the comparative example, the compression chamber pressure reaches the high pressure Pd at the rotation phase θc. Pd is reached. That is, in the first embodiment, the compression chamber pressure rises more slowly than in the comparative example. Therefore, in the first embodiment, the differential pressure between the compression chambers 12 is reduced compared to the comparative example, and the amount of refrigerant leakage between the compression chambers 12 is reduced, so that the efficiency of the compressor can be increased.

Although FIG. 6 illustrates a sudden increase in the volume of the compression chamber when the compression chamber 12 reaches the stepped portion, this diagram is an example and is not limited to the illustrated mode. That is, the manner in which the volume of the compression chamber changes varies depending on the configuration of the step. Therefore, there are cases where the compression chamber volume gently increases, and there are cases where the compression chamber volume does not increase. The case where the compression chamber volume does not increase is the case where the volume expansion ratio due to the step and the volume reduction ratio of the spiral body are the same, and when the compression chamber 12 reaches the stepped portion, the compression chamber volume at that point It refers to continuing for a constant rotation phase.

Here, with carbon dioxide alone or a mixed refrigerant containing carbon dioxide, the rate of increase in pressure with respect to reduction in the volume of the compression chamber is large, as described above. For this reason, when compressing carbon dioxide alone or a mixed refrigerant containing carbon dioxide in the structure of the comparative example in which the compression chamber volume decreases linearly, the pressure in the compression chamber 12 rises to the target high pressure Pd with a small number of rotations. it rises. Therefore, the number of turns of the spiral body cannot be increased.

In contrast, in Embodiment 1, the volume reduction rate can be reduced as described above, so even if carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used, the compression chamber pressure rises with an increase in the rotation phase. can reduce the ratio of Therefore, it is possible to increase the number of compression chambers 12 by increasing the number of turns of the spiral body. As a result, the differential pressure between the compression chambers can be reduced, and a scroll compressor capable of reducing refrigerant leakage can be obtained.

As described above, the scroll compressor of the first embodiment includes a fixed scroll 1 having a fixed base plate 1c and a fixed spiral body 1b formed on the fixed base plate 1c, a swing base plate 2c and a swing base. It has an oscillating spiral body 2b formed on a plate 2c, and the oscillating base plate 2c is arranged so as to face the fixed base plate 1c. an oscillating scroll 2 forming 12; In the scroll compressor of Embodiment 1, the distance between the base plates, which is the distance between the fixed base plate 1c and the oscillating base plate 2c, is set to It has a structure that gradually increases toward the center.

As a result, even when a single carbon dioxide or a mixed refrigerant containing carbon dioxide is used as the refrigerant, it is possible to reduce refrigerant leakage between the compression chambers and suppress deterioration in performance.

The fixed spiral body 1b and the oscillating spiral body 2b are provided with spiral-side stepped portions 40 such that tooth heights, which are heights of the respective spiral bodies, increase stepwise from the outer peripheral portion to the central portion. The fixed base plate 1c and the rocking base plate 2c are provided with a base plate-side stepped portion 41 corresponding to the spiral-side stepped portion 40 of the spiral body facing each other. is formed thinly.

In this manner, a structure can be constructed in which the distance between the base plates increases stepwise from the outer peripheral portion to the central portion of the fixed spiral body 1b and the oscillating spiral body 2b.

The fixed scroll 1 and the orbiting scroll 2 are made of different materials, and the tooth thickness of the fixed scroll 1b and the orbiting scroll 2b, which has the lower tensile strength, is thicker.

As a result, the tooth thickness of the lower tensile strength can be secured, and the strength can be maintained.

Embodiment 2.
In the first embodiment, a configuration has been described in which the distance between the base plates is longer on the central side than on the outer peripheral side with respect to each step provided on each of the fixed scroll 1 and the oscillating roll. In the second embodiment, in addition to the structure of the first embodiment, the thickness of the spiral body is changed to further reduce the volume reduction rate of the compression chamber 12 accompanying the eccentric orbiting motion of the orbiting scroll 2. A configuration that can further improve the performance by doing so will be described. The following description will focus on the differences of the second embodiment from the first embodiment, and the configurations not described in the second embodiment are the same as those of the first embodiment.

FIG. 8 is an enlarged view of a compression chamber of a scroll compressor according to Embodiment 2. FIG.
The tooth thickness, which is the radial thickness of the fixed spiral body 1b, is configured to smoothly decrease from the outer peripheral portion toward the central portion. That is, the relationship between the tooth thickness tfo on the outer peripheral side and the tooth thickness tfi on the central side of the stationary spiral body 1b is configured to satisfy tfo>tfi. Similarly, the tooth thickness, which is the radial thickness of the oscillating spiral body 2b, is configured to smoothly decrease from the outer peripheral portion toward the central portion in the spiral direction. That is, the relationship between the tooth thickness too on the outer peripheral side and the tooth thickness toi on the central side of the oscillating spiral body 2b satisfies too>toi. However, since the central portion of the spiral receives the highest differential pressure, it is formed thicker than the other portions in order to ensure strength.

The relationship between the tooth thickness of the stationary spiral body 1b and the tooth thickness of the oscillating spiral body 2b may be the same if the spiral bodies are made of the same material, or if the materials are different, the one with the lower material strength is thicker. Also good. In any case, in Embodiment 2, the tooth thickness of each of the fixed spiral body 1b and the oscillating spiral body 2b is configured to smoothly decrease from the outer peripheral portion toward the central portion. Moreover, both the tooth thickness of the fixed spiral body 1b and the tooth thickness of the oscillating spiral body 2b are configured to be thinner from the outer peripheral portion toward the central portion, but either one may be reduced.

FIG. 9 is a change diagram of the compression chamber volume with respect to the rotational phase of the oscillating spiral body in the scroll compressor according to the second embodiment. The horizontal axis is the rotational phase [°] of the oscillating spiral, and the vertical axis is the compression chamber volume [cc]. In FIG. 9, a thick solid line indicates the second embodiment. A thin solid line indicates the first embodiment. A dashed-dotted line indicates a case without a stepped structure as a comparative example.
In the second embodiment, the tooth thickness of each of the fixed spiral body 1b and the oscillating spiral body 2b smoothly decreases from the outer peripheral portion to the central portion, so that the compression chambers 12 are formed in the first and second stages. The compression chamber volume after the increase in compression chamber volume when reaching each eye is larger than that in the first embodiment. The difference in compression chamber volume between the second embodiment and the first embodiment increases as the rotation phase advances. Therefore, in the second embodiment, the compression chamber 12 has a smaller volume reduction ratio than in the first embodiment.

FIG. 10 is a change diagram of the compression chamber pressure with respect to the rotational phase of the oscillating spiral body in the scroll compressor according to Embodiment 2. FIG. The horizontal axis represents the rotational phase [°] of the oscillating spiral body 2b, and the vertical axis represents the compression chamber pressure [MPaG]. In FIG. 10, a thick solid line indicates the second embodiment. A thin solid line indicates the first embodiment. A dashed-dotted line indicates a case without a stepped structure as a comparative example.
Comparing the second embodiment with the first embodiment and the comparative example, the compression chamber pressure similarly rises until the compression chamber 12 reaches the first stage. In the comparative example, the compression chamber pressure rises as the rotation phase progresses after that as well. On the other hand, in Embodiments 2 and 1, when the compression chamber 12 reaches the first stage, the volume of the compression chamber increases, the refrigerant in the compression chamber 12 expands, and the compression chamber pressure decreases.

Here, in the second embodiment, as described above, the increased compression chamber volume when the compression chamber 12 reaches the first stage is larger than that in the first embodiment. Therefore, the compression chamber pressure is lowered to a pressure lower than that of the first embodiment. Similarly, when the compression chamber 12 reaches the second stage, the compression chamber pressure is lowered to a pressure lower than that of the first embodiment. As described above, in the second embodiment, the pressure in the compression chamber is lower than in the first embodiment at each stepped portion, so that the speed of pressure increase in the compression chamber 12 is slower than in the first embodiment. Therefore, in the second embodiment, the differential pressure between the compression chambers 12 is smaller than that in the first embodiment, and the leakage amount of refrigerant between the compression chambers 12 is further reduced, so that the efficiency of the compressor can be further improved.

As described above, in the second embodiment, the tooth thickness, which is the radial thickness of at least one of the fixed spiral body 1b and the oscillating spiral body 2b, is configured to become thinner from the outer peripheral portion toward the central portion. Therefore, the volume reduction rate of the compression chamber 12 becomes smaller than that of the first embodiment. Therefore, even if carbon dioxide alone or a mixed refrigerant containing carbon dioxide is used, the rate at which the pressure rises can be reduced. Since the rate at which the pressure rises can be reduced in this way, it is possible to increase the number of compression chambers 12 by increasing the number of turns of the spiral body. As a result, the differential pressure between the compression chambers 12 can be reduced, and the second embodiment can further reduce the amount of refrigerant leakage and improve the efficiency of the compressor as compared with the first embodiment.

In Embodiments 1 and 2, the fixed base plate 1c is provided with an intermediate injection port 50 (see FIGS. 3 and 8) to inject intermediate-pressure liquid refrigerant or gas refrigerant into the compression chamber 12. You may do so. When the liquid refrigerant is injected, the refrigerant in the compression chamber can be cooled by the liquid refrigerant, and an increase in the temperature of the discharge gas during operation at a high compression ratio can be suppressed. Further, when the economizer cycle is configured to inject the gas refrigerant, the refrigerating capacity can be increased. The injection port 50 is arranged at the position shown in FIGS. 3 and 8 or closer to the center of the spiral than that position. If the intermediate injection port 50 communicates with the low-pressure space 23 , the cooling effect of the compression chamber 12 is reduced.

REFERENCE SIGNS LIST 1 fixed scroll 1a discharge port 1b fixed spiral body 1c fixed bed plate 2 oscillating scroll 2b oscillating spiral body 2c oscillating bed plate 2d boss portion 2e oscillating bearing portion 3 frame 3a bearing Part 3b Thrust bearing part 4 Subframe 4a Bearing part 7 Rotating shaft 7a Eccentric part 8 Suction pipe 9 Discharge pipe 11 Shell 12 Compression chamber 14 Valve holder 15 Valve 19 Stator 20 Rotor , 21 oil reservoir, 22 oil pump, 23 low-pressure space, 24 high-pressure space, 25 Oldham ring, 36 compression mechanism, 37 drive mechanism, 40 spiral side step, 41 base plate side step, 50 injection port.

Claims (5)

a fixed scroll having a fixed base plate and a fixed scroll body formed on the fixed base plate;
a rocking bed plate and a rocking spiral body formed on the rocking bed plate; the rocking bed plate is disposed so as to face the fixed bed plate; an orbiting scroll combined with the body to form a compression chamber,
A structure in which the distance between the base plates, which is the distance between the fixed base plate and the swing base plate, increases stepwise from the outer peripheral portion of the fixed spiral body and the swing spiral body toward the central portion thereof. have
The fixed spiral body and the oscillating spiral body are provided with spiral-side stepped portions so that tooth heights, which are heights of the respective spiral bodies, increase stepwise from the outer peripheral portion toward the central portion. ,
The fixed base plate and the rocking base plate are provided with base plate-side stepped portions corresponding to the spiral-side stepped portions of the facing spiral bodies, and the plate thickness is stepped from the outer peripheral portion toward the central portion. A scroll compressor that is relatively thin . 2. A scroll compressor according to claim 1, wherein a tooth thickness, which is a thickness in a radial direction of at least one of said fixed spiral body and said oscillating spiral body, is configured to decrease from said outer peripheral portion toward said central portion. a fixed scroll having a fixed base plate and a fixed scroll body formed on the fixed base plate;
a rocking bed plate and a rocking spiral body formed on the rocking bed plate; the rocking bed plate is disposed so as to face the fixed bed plate; an orbiting scroll combined with the body to form a compression chamber,
A structure in which the distance between the base plates, which is the distance between the fixed base plate and the swing base plate, increases stepwise from the outer peripheral portion of the fixed spiral body and the swing spiral body toward the central portion thereof. have
As the structure,
A scroll compressor in which a tooth thickness, which is a thickness in a radial direction of at least one of the fixed spiral body and the oscillating spiral body, is configured to decrease from the outer peripheral portion toward the central portion. The fixed scroll and the oscillating scroll are made of different materials, and the tooth thickness of the fixed scroll and the oscillating scroll having a lower tensile strength is thicker . The scroll compressor according to any one of 1 . The scroll compressor according to any one of claims 1 to 4, wherein the refrigerant compressed in the compression chamber is carbon dioxide alone or a mixed refrigerant containing carbon dioxide.

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