compressor

Abstract

In compressors, this suppresses the increase in oil consumption. [Solution] The compressor (10) comprises a sealed container (1), a motor (2) having a rotor (21) and a stator (22) disposed inside the sealed container (1), and a compression mechanism (3) disposed below the motor (2) inside the sealed container (1) and driven by the motor (2). The stator (22) has a stator core (23) with a notch (23d) between it and the inner wall (1a) of the sealed container (1) that serves as a refrigerant flow path (P1). The cross-sectional area of ​​the flow path (P1) in a cross section perpendicular to the axial direction of the stator core (23) is smaller than the opening area at the upper end of the flow path (P1) in at least a portion from the lower end to the upper end.

Description

Technical Field

[0001] The present disclosure relates to a compressor.

Background Art

[0002] Conventionally, compressors for compressing refrigerant are known. For example, Patent Document 1 discloses a rotary compressor. The rotary compressor includes a dome-shaped casing, a compression mechanism and a motor housed therein, and is configured as a hermetic type. The motor includes a stator fixed to the body of the casing and a rotor having a drive shaft connected thereto and disposed inside the stator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 discloses that by providing a core cut on the outer peripheral surface of the stator, a refrigerant passage that communicates the spaces on both axial sides of the motor is formed between the stator and the inner wall of the casing. Lubricating oil passes through the refrigerant passage in addition to the refrigerant, and part of the lubricating oil that has moved from below the motor to above does not return to the lower space but is circulated outside the compressor. When the ratio of the lubricating oil that does not return (oil lift rate) increases in this way, various adverse effects such as insufficient lubrication and performance degradation occur.

[0005] An object of the present disclosure is to suppress an increase in the oil lift rate without degrading the motor performance in a compressor with increased capacity.

Means for Solving the Problems

[0006] A first aspect of the present disclosure is a compressor (10) comprising a sealed container (1), a motor (2) having a rotor (21) disposed inside the sealed container (1) and fixed to a vertically extending rotating shaft (4), and a stator (22) fixed to the sealed container (1), and a compression mechanism (3) disposed below the motor (2) inside the sealed container (1) and driven by the motor (2) to compress a refrigerant. The stator (22) has a stator core (23) with an axially extending notch (23d) provided on its outer circumferential surface. A refrigerant flow path (P1) is formed between the notch (23d) and the sealed container (1), and the cross-sectional area of ​​the flow path (P1) in a cross-section along a horizontal plane at a first height, which is the upper end of the stator core (23), is larger than the cross-sectional area of ​​the flow path (P1) in a cross-section along a horizontal plane at a second height, which is lower than the first height.

[0007] According to the first embodiment, the cross-sectional area of ​​the flow path (P1) has the above configuration, which promotes the fall of lubricating oil as it passes from the lower end to the upper end of the stator core (23), thereby suppressing an increase in the oil rise rate.

[0008] The second embodiment is the first embodiment, wherein the flow path (P1) has a region where the cross-sectional area is constant or decreases as it moves from the lower end to the upper end.

[0009] According to the second embodiment, the flow velocity inside the flow channel (P1) can be adjusted by having a region in the flow channel (P1) where the cross-sectional area is constant or decreases.

[0010] The third embodiment is the first embodiment, wherein the cross-sectional area of ​​the flow path (P1) increases uniformly from the lower end to the upper end.

[0011] According to the third embodiment, by increasing the cross-sectional area of ​​the flow path (P1) from the lower end to the upper end, the flow velocity of the refrigerant flowing in the flow path (P1) can be reduced, making it easier for oil droplets contained in the refrigerant to fall to the bottom due to gravity.

[0012] The fourth embodiment is the first embodiment, wherein the flow path (P1) has a stepped portion (25) in which the cross-sectional area changes in a stepped manner as it moves from the lower end to the upper end.

[0013] In the fourth embodiment, the presence of a stepped portion (25) allows for a greater pressure loss in the refrigerant flowing through the flow path (P1), thereby reducing the flow velocity. This significantly promotes the fall of lubricating oil. Furthermore, when the stator core (23) is constructed by laminating steel plates, the number of steel plate shapes can be reduced, which is advantageous in terms of production yield.

[0014] The fifth embodiment is the fourth embodiment, wherein the stepped portion (25) is located below the axial center of the stator core (23).

[0015] In the fifth embodiment, by positioning the stepped portion (25) below the axial center, it becomes possible to secure a sufficient distance to decelerate the fluid.

[0016] The sixth embodiment is, in the first embodiment, an inner passage (P2) through which a refrigerant flows is provided radially inside the stator (22), and the opening area at the upper end of the flow path (P1) is larger than the cross-sectional area of ​​the inner passage (P2).

[0017] In the sixth embodiment, by making the cross-sectional area of ​​the flow path (P1) larger than that of the inner passage (P2), the refrigerant passage becomes mainly the flow path (P1) formed by the notch (23d). This makes the effect of promoting the fall of lubricating oil in the flow path (P1) more pronounced.

[0018] The seventh embodiment is a refrigeration system comprising a compressor (10) according to the first to sixth embodiments and a refrigerant circuit (51a) through which the refrigerant compressed by the compressor (10) flows.

[0019] In the seventh embodiment, a refrigeration system is realized that includes a compressor (10) that suppresses an increase in the oil consumption rate. [Brief explanation of the drawing]

[0020] [Figure 1] FIG. 1 is a diagram schematically showing the configuration of a refrigeration cycle apparatus including the compressor of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the compressor of an embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view showing the arrangement configuration of a sealed container and a stator in the compressor of the embodiment. [Figure 4] FIG. 4 is a perspective view showing the stator included in the compressor of the embodiment. [Figure 5] FIG. 5 is a diagram showing another example of the shape of a notch portion provided in a stator core.

MODE FOR CARRYING OUT THE INVENTION

[0021] <<Embodiment 1>> Hereinafter, Embodiment 1 of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of the present disclosure. Since each drawing is for conceptually explaining the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for easy understanding.

[0022] <Refrigeration Cycle Apparatus> As shown in FIG. 1, the compressor (10) of the present embodiment is provided in a refrigeration cycle apparatus (51). The refrigeration cycle apparatus (51) has a refrigerant circuit (51a) filled with a refrigerant. The refrigerant circuit (51a) has a scroll compressor (10), a radiator (53), a decompression mechanism (54), and an evaporator (55). The decompression mechanism (54) is, for example, an expansion valve. The refrigerant circuit (51a) performs a vapor compression refrigeration cycle.

[0023] The refrigeration cycle device (51) is an air conditioning device. The air conditioning device may be a cooling-only unit, a heating-only unit, or an air conditioning device that switches between cooling and heating. In this case, the air conditioning device has a switching mechanism (e.g., a four-way switching valve) that switches the direction of circulation of the refrigerant. The refrigeration device (51) may be a water heater, a chiller unit, a cooling device that cools the air inside a storage unit, etc. The cooling device cools the air inside a refrigerator, freezer, container, etc.

[0024] <Compressor Configuration> As shown in Figure 2, the present invention compressor (10) mainly comprises a sealed container (1), a motor (2), and a compression mechanism (3). In this invention, a rotary compressor is used as an example of the compressor (10), but the compressor to which the technology described in this embodiment is applied is not limited to rotary compressors. The technology described in this embodiment can also be applied to compressors other than rotary compressors, such as scroll compressors. A rotary compressor is a compressor that compresses the gas in a compression chamber formed in a cylinder by eccentrically rotating a piston within the cylinder. Rotary compressors generally have vanes to partition the compression chamber. Rotary compressors include so-called rolling piston types in which vanes separate from the piston contact the piston while the piston rotates eccentrically, so-called swing types in which vanes formed integrally with the piston swing along with the eccentric rotation of the piston, and so-called hinge vane types in which the tip of the vane is rotatably fitted into a recess on the outer surface of the piston while the piston rotates eccentrically.

[0025] The motor (2) is located inside the sealed container (1). The motor (2) has a rotor (21) mounted on a vertically extending rotating shaft (4) and a stator (22) fixed to the sealed container (1).

[0026] The compression mechanism (3) is located below the motor (2) inside the sealed container (1). The compression mechanism (3) is driven by the motor (2) to compress the refrigerant.

[0027] One end of the suction pipe (11) is connected to the compression mechanism (3) on the lower side of the sealed container (1). The other end of the suction pipe (11) is connected to an accumulator (15) located adjacent to the sealed container (1). The refrigerant gas (low-pressure refrigerant) supplied from the suction pipe (11) to the compressor (10) via the accumulator (15) is guided to the suction side of the compression mechanism (3). In this example, the compression mechanism (3) has a two-stage configuration, and two suction pipes (11) are provided, each connected to a cylinder in each stage.

[0028] A discharge pipe (12) is connected to the space above the motor (2) in the sealed container (1). Compressed refrigerant gas (high-pressure refrigerant) from the compression mechanism (3) is discharged from the discharge pipe (12). The suction pipe (11) and the discharge pipe (12) penetrate the sealed container (1) and are fixed to the sealed container (1) to ensure its airtightness. The sealed container (1) is formed to be airtight, except that the suction pipe (11) and the discharge pipe (12) communicate with the outside of the sealed container (1).

[0029] In the lower space of the compression mechanism (3) within the sealed container (1), an oil reservoir for lubricating oil is formed to lubricate the drive part of the compression mechanism (3). The lubricating oil is refrigerant oil used to improve the lubrication of the sliding parts in the internal space of the sealed container (1).

[0030] The compression mechanism (3) comprises a cylindrical body (31). The rotating shaft (4) is inserted into the body (31). The rotating shaft (4) is rotatably supported by bearings provided at the upper and lower ends of the compression mechanism (3), respectively. A crankpin (32) is provided on the rotating shaft (4) inside the body (31), and in the compression mechanism (3), a compression chamber (34) for compressing the refrigerant is formed between the piston (33), which is fitted into and driven by the crankpin (32), and the body (31). The piston (33) rotates or revolves eccentrically with respect to the axis of the rotating shaft (4), changing the volume of the compression chamber (34). As a result, the refrigerant gas is compressed.

[0031] The motor (2) drives the compression mechanism (3) via a rotating shaft (4). The motor (2) is positioned in a high-pressure region within a sealed container (1) that is filled with high-pressure refrigerant gas discharged from the compression mechanism (3). The motor (3) comprises a cylindrical rotor (21) fixed to the rotating shaft (4) and a stator (22) positioned opposite the rotor (21) with an air gap in the radial direction. The rotor (21) has a rotor core made of multiple metal plates stacked along the vertical direction, and magnets are embedded in the rotor core. The stator (22) is a cylindrical member fixed to the inner wall of the sealed container (1).

[0032] The rotor (21) has a cylindrical rotor core (24) and permanent magnets (not shown). The rotor core (24) is fixed to the top of the rotating shaft (4) and is positioned inside the stator core (23) with a gap. The rotor (21) rotates by exerting magnetic interaction with the stator (21), causing the rotating shaft (4) to rotate.

[0033] The rotating shaft (4) is positioned inside the cylindrical casing (1) so that its central axis coincides with the other shaft. The rotor (21) of the motor (2) is fixed to the upper part of the rotating shaft (4).

[0034] In this disclosure, "radial direction" refers to the direction perpendicular to the axis of rotation (4), "circumferential direction" refers to the circumferential direction of a circle centered on the axis of rotation (4), and "axial direction" refers to the direction in which the axis of rotation (4) extends, that is, the "up and down direction."

[0035] (Stator core) As shown in Figure 3, the stator (22) has a stator core (23) and a coil (not shown). The stator core (23) has a cylindrical core back portion (23a) and a plurality of teeth portions (23b) (9 in this embodiment) that protrude radially inward from the inner circumferential surface of the core back portion (23a). The stator core may be constructed of laminated electrical steel sheets, for example.

[0036] Inside the core back portion (23a) of the stator core (23), multiple teeth portions (23b) divide the space between each tooth portion (23b) into slots (23c) where coils are placed, equal to the number of teeth portions (23b). On the other hand, multiple notches (23d) are formed on the outer circumference of the core back portion (23a) of the stator core (23). The notches (23d) are recesses that are inwardly recessed relative to the imaginary circumferential surface (a circumferential surface in which the circumferential surface in contact with the sealed container (1) forms part) centered on the rotation axis of the stator core (23). The notches (23d) are formed from the upper end surface to the lower end surface of the stator core (23), and nine notches are formed to correspond to the nine teeth portions (23b).

[0037] The notch (23d) and the inner wall (1a) of the sealed container (1) form a refrigerant flow path (P1). The lubricating oil also passes through this flow path (P1). The notch (23d) and the flow path (P1) will be explained further later.

[0038] The core back portion (23a) has nine notches (23d) that form nine protruding portions (23e) that project outward, and the nine protruding portions (23e) are fixed to the inner surface (1a) of the side wall portion of the casing (1) by welding or the like.

[0039] Figure 4 further illustrates the stator core (23). Figure 4 is a perspective view showing only the stator core (23). Multiple notches (23d) are provided on the outer circumferential surface of the stator core (23) as grooves extending in the axial direction (up and down direction).

[0040] The notch (23d) has a change in cross-sectional area in the vertical direction. In the example in Figure 4, the notch (23d) is composed of a lower notch (23f) located below and an upper notch (23g) located above it, which has a larger cross-sectional area than the lower notch (23f). In other words, the notch (23d) has a stepped section (25) in which the cross-sectional area changes in a stepped manner from the lower end to the upper end.

[0041] Furthermore, "cross-sectional area of ​​the notch" refers to the area of ​​the space formed by the notch (23d) (lower notch (23f), upper notch (23g)) and the inner wall (1a) of the sealed container (1) in a cross section perpendicular to the axial direction. Therefore, the cross-sectional area of ​​the notch (b) is the same as the cross-sectional area of ​​the flow path (P1) at that location.

[0042] In the example shown in Figure 4, the lower notch (23f) and the upper notch (23g) each have no change in width or cross-sectional area in the vertical direction. Therefore, the opening area at the lower end of the notch (23d) (lower notch (23f)) is equal to the cross-sectional area of ​​the lower notch (23f). Similarly, the opening area at the upper end of the notch (23d) (upper notch (23g)) is equal to the cross-sectional area of ​​the upper notch (23g). Furthermore, the cross-sectional area of ​​the flow path in the lower notch (23f) is smaller than the opening area of ​​the flow path at the upper end of the notch (23d).

[0043] The cross-sectional area of ​​the stator core (23) along the horizontal plane (a plane perpendicular to the axial direction) at the first height, which is the upper end of the stator core, is larger than the cross-sectional area of ​​the cross-sectional area of ​​the stator core (23) along the horizontal plane at the second height (the height included in the lower notch (23f)), which is lower than the first height.

[0044] The notch (23d) having this shape helps to suppress an increase in the oil consumption rate (the proportion of lubricating oil that does not return from the space above the motor out of the total amount of lubricating oil).

[0045] In the flow path (P1), the refrigerant passes from the lower end to the upper end, and lubricating oil is carried along with it. At this time, the cross-sectional area of ​​the flow path (P1) increases midway, that is, at the stepped section (25) where the lower notch (23f) and the upper notch (23g) connect, causing the flow velocity of the refrigerant and lubricating oil to decrease. As a result, the effect of gravity acting on the lubricating oil becomes relatively larger, and the lubricating oil tends to fall downwards.

[0046] Furthermore, by increasing the opening area at the upper end of the flow path (P1), lubricating oil transported to the upper space of the motor (2) can more easily enter the flow path (P1), and a larger proportion of it will fall into the lower space. On the other hand, by decreasing the opening area at the lower end of the flow path (P1), it becomes more difficult for lubricating oil to enter the flow path (P1) from the lower end, thereby reducing the amount of lubricating oil transported to the upper space of the motor.

[0047] Based on these findings, it is possible to suppress the increase in oil consumption rate (reduce the oil consumption rate) by changing the cross-sectional area of ​​the notched portion (23d).

[0048] The stepped portion where the cross-sectional area of ​​the flow path (P1) changes is preferably located below the axial center of the stator core (23). Since the flow velocity decreases as the lubricating oil flows into the upper notch (23g) with a wider cross-sectional area, and the fall of the lubricating oil is promoted, it is preferable that the stepped portion (25) be located close to the lower end.

[0049] Note that the shape of the notch (23d) is not limited to the example in Figure 4. Figure 5 shows examples A to F illustrating how the cross-sectional area of ​​the notch (23d) changes. These schematically represent the shape of the notch (23d) when the stator core (23) is viewed from the side, and show the change in cross-sectional area from the lower end to the upper end. The figure shows the change in the width of the notch (23d), but it can also be considered to show the change in cross-sectional area taking into account the depth and shape of the notch (23d).

[0050] A corresponds to the notch (23d) shown in Figure 4. In other words, the notch (23d) of A is configured such that the lower end side, which has a relatively small cross-sectional area, and the upper end side, which has a larger cross-sectional area, are connected, and the cross-sectional area changes in a stepped manner.

[0051] In this case, the presence of the stepped portion (25) imposes a large pressure loss on the refrigerant flowing through the flow path (P1), causing a rapid decrease in flow velocity. This makes it possible to more reliably obtain the effect of dropping the lubricating oil.

[0052] In case B, the cross-sectional area of ​​the notch (23d) increases uniformly without any steps from the lower end to the upper end of the stator core (23). The way in which it changes is constant, and the side wall of the notch (23d) is a straight line at an angle with respect to the axial direction. In this case as well, by gradually increasing the cross-sectional area from the lower end to the upper end, the flow velocity of the refrigerant in the flow path (P1) can be gradually reduced, thereby promoting the fall of the lubricating oil.

[0053] In case C as well, the cross-sectional area of ​​the notch (23d) gradually increases without any steps from the lower end to the upper end of the stator core (23). However, the change is more pronounced towards the upper end, and the side walls of the notch (23d) are, for example, streamlined.

[0054] In case D, there is a central notch (23h) between the lower notch (23f) and the upper notch (23g), which has a larger cross-sectional area, and the central notch (23h) has an even smaller cross-sectional area than the lower notch (23f). In this case as well, the flow velocity of the refrigerant and lubricating oil decreases as they pass from below through the central notch (23h) and enter the upper notch (23g), resulting in the effect of causing the lubricating oil to fall. Furthermore, as can be seen from the effect shown in case D, the lower end of the flow path (P1) formed by the notch (23d) does not need to have the largest cross-sectional area. It is sufficient that at least a portion of the flow path from the lower end to the upper end (the central notch (23h) in the example of D) has a cross-sectional area smaller than the opening area at the upper end of the notch (23d).

[0055] In case E, the notch (23d) is configured such that a central notch (23h) with a constant cross-sectional area is sandwiched between a lower notch (23f) and an upper notch (23g), where the cross-sectional area gradually increases from the lower end to the upper end. In this case as well, having a portion with a wider cross-sectional area at the upper end can promote the dripping of lubricating oil contained in the refrigerant.

[0056] In case F, the cross-sectional area of ​​the notch (23d) changes without any steps. The opening area at the upper end is larger than the opening area at the lower end, and there is a region between the lower and upper ends where the cross-sectional area is smaller. Even in this shape, the effect of promoting the flow of lubricating oil is still achieved.

[0057] Even with shapes other than A to F, the presence of a portion (second height) in which the cross-sectional area is smaller than the opening area at the first height (upper end of the stator core (23)) in at least a part of the notch (23d) (flow channel (P1)) from the lower end to the upper end, has the effect of suppressing (or reducing) the oil consumption rate. For example, in A, the notch (23d) has two parts with different cross-sectional areas, but it may also have three or more parts with different cross-sectional areas, with the cross-sectional area gradually increasing from the lower end to the upper end.

[0058] The stator core (23) may be constructed by laminating electromagnetic steel sheets cut to a predetermined shape. In this case, the cross-sectional area of ​​the notch (23d) can be changed by adjusting the notch corresponding to the notch (23d) in each electromagnetic steel sheet. In particular, the example A in Figures 4 and 5 can be easily realized by laminating two types of electromagnetic steel sheets, each having a notch of a size and shape corresponding to the lower notch (23f) and the upper notch (23g), respectively. The example D in Figure 5 can also be realized with three types of electromagnetic steel sheets.

[0059] Furthermore, as shown in Figure 4, an example is shown where the cross-sectional shape of the notch (23d) is cut in an isosceles trapezoidal shape relative to the circumference. However, other shapes, such as an arc shape, may also be used. In addition, although the cross-sectional area is changed by changing both the width and depth of the notch (23d) in Figure 4, it is also possible to change only one of the width or depth.

[0060] (Relationship with flow paths inside the stator core) In the compressor (10), a refrigerant flow path (hereinafter referred to as the inner passage) also exists inside the stator core (23). For example, in Figure 3, the gap between the stator (22) and the rotor (21) functions as the inner passage (P2). In addition to the flow path (P1) formed by the notch (23d), the refrigerant moves from the lower space to the upper space of the motor (2) through the inner passage (P2), and the lubricating oil moves similarly at this time.

[0061] The effect of suppressing the increase in oil consumption rate by using the notch (23d) shape described in Figures 4 and 5 is exerted on the refrigerant and lubricating oil passing through the flow path (P1) formed by the notch (23d). Therefore, it is preferable that the refrigerant and lubricating oil mainly pass through the flow path (P1) with priority over the inner passage (P2). To achieve this, it is preferable that the cross-sectional area of ​​the flow path (P1) is larger than the cross-sectional area of ​​the inner passage (P2). In particular, it is preferable that the opening area at the upper end of the flow path (P1) is larger than the cross-sectional area of ​​the inner passage (P2).

[0062] With this configuration, the effect of promoting the fall of lubricating oil in the flow path (P1) and suppressing the increase in the oil consumption rate is more pronounced.

[0063] Although embodiments and modifications have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. [Industrial applicability]

[0064] As explained above, this disclosure is useful for compressors. [Explanation of Symbols]

[0065] 1. Airtight container 1a Inner wall 2 motors 3. Compression mechanism 4 rotation axes 10 Compressor 21 Rotors 22 stata 23 Stator Core 23d Notch 25 Stepped section 51 Refrigeration cycle equipment 51a Refrigerant circuit P1 channel P2 inner passage

Claims

1. A sealed container (1), A motor (2) is provided, which is located inside the sealed container (1) and has a rotor (21) fixed to a vertically extending rotating shaft (4), and a stator (22) fixed to the sealed container (1). A compression mechanism (3) is located below the motor (2) inside the sealed container (1) and is driven by the motor (2) to compress the refrigerant. Equipped with, The stator (22) has a stator core (23) on its outer circumferential surface, which is provided with a notch (23d) extending in the axial direction. A refrigerant flow path (P1) is formed between the notch (23d) and the sealed container (1). A compressor characterized in that the cross-sectional area of ​​the flow path (P1) in a cross-section along a horizontal plane at a first height which is the upper end of the stator core (23) is larger than the cross-sectional area of ​​the flow path (P1) in a cross-section along a horizontal plane at a second height which is lower than the first height.

2. In the compressor (10) according to claim 1, The compressor (10) is characterized in that the flow path (P1) has a region where the cross-sectional area is constant or decreases from the lower end to the upper end.

3. In the compressor (10) according to claim 1, The compressor (10) is characterized in that the cross-sectional area of ​​the flow path (P1) increases uniformly from the lower end to the upper end.

4. In the compressor (10) according to claim 1, The compressor (10) is characterized in that the flow path (P1) has a stepped section (25) in which the cross-sectional area changes in a stepped manner from the lower end to the upper end.

5. In the compressor (10) according to claim 4, The compressor (10) is characterized in that the stepped portion (25) is located below the axial center of the stator core (23).

6. In the compressor (10) of claim 1, The stator (22) is provided with an inner passage (P2) through which the refrigerant flows, located radially inward. A compressor (10) characterized in that the opening area at the upper end of the flow path (P1) is larger than the cross-sectional area of ​​the inner passage (P2).

7. The compressor (10) of claim 1, The system includes a refrigerant circuit (51a) through which the refrigerant compressed by the compressor (10) flows. Refrigeration equipment.

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