JP2008180143A - Hermetic compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hermetic compressor capable of reducing noise and a pressure loss, while improving durability in a valve plate. <P>SOLUTION: This hermetic compressor 1 has a cylinder 27, a delivery port 35, a seat part 37, the valve plate 36 and a casing 2. The cylinder 27 compresses a refrigerant. The refrigerant compressed by the cylinder 27 flows in the delivery port 35. The seat part 37 has an opening 37a communicating with the delivery port 35. The valve plate 36 is arranged in a position contacting with the seat part 37. The valve plate 36 stops a backflow to the inside of the cylinder 27 of the refrigerant in the delivery port 35. The casing 2 stores the cylinder 27, the seat part 37 and the valve plate 36. A plane shape of the opening 37a of the seat part 37 is a noncircular shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hermetic compressor.

Conventionally, various hermetic compressors for compressing a compression medium such as refrigerant gas have been proposed. In the hermetic rotary compressor described in Patent Document 1, the refrigerant gas sucked from the suction port is compressed by the eccentric rotation of the rolling piston inside the cylinder, and the compressed refrigerant gas is discharged from the cylinder through the discharge port having the discharge valve. . Further, the gas compressor described in Patent Document 2 shows a structure in which a discharge port is closed by a reed valve. In these compressors, the circular discharge port is closed by a thin plate-shaped reed valve or the like, but the compressed refrigerant gas is discharged to the outside of the cylinder by pushing the reed valve open by the pressure.
JP 2001-132673 A JP 2004-68780 A

  In the hermetic compressors described in Patent Documents 1 and 2, the larger the discharge port diameter (so-called sheet diameter) from the compressor, the slower the flow rate of the refrigerant gas near the discharge port, but the differential pressure applied to the valve plate. In order to ensure fatigue strength against tensile stress due to, it cannot be increased beyond a certain level. On the other hand, if the flow passage area of the discharge port is reduced, the flow rate of the refrigerant gas increases in inverse proportion to this, so that there is a problem that noise and pressure loss increase.

  An object of the present invention is to provide a hermetic compressor capable of improving the durability of a valve plate and reducing noise and pressure loss.

  The hermetic compressor of the first invention includes a cylinder, a discharge port, a seat portion, a valve plate, and a casing. The cylinder compresses the refrigerant. The refrigerant compressed by the cylinder flows through the discharge port. The sheet portion has an opening communicating with the discharge port. The valve plate is provided at a position in contact with the seat portion. The valve plate stops the reverse flow of the refrigerant into the cylinder at the discharge port. The casing houses a cylinder, a seat portion, and a valve plate. The planar shape of the opening of the seat portion is non-circular.

  Here, since the planar shape of the opening of the seat portion is non-circular, it is possible to ensure the fatigue strength of the valve plate even if the flow path area is the same. Thereby, it becomes possible to enlarge a flow path area, maintaining the safety factor of the fatigue strength of a valve plate. As a result, the flow rate of the refrigerant at the opening of the seat portion can be reduced, and noise and pressure loss can be reduced.

  The hermetic compressor of the second invention is the hermetic compressor of the first invention, wherein the planar shape of the opening of the seat portion is greater than that in the case where the maximum stress generated when the valve plate is pressed against the seat portion is circular. It is a non-circular shape that also becomes smaller.

  Here, the planar shape of the opening of the seat portion is a non-circular shape in which the maximum stress generated when the valve plate is pressed against the seat portion is smaller than in the case of a circular shape. For this reason, it is possible to further improve the durability of the valve plate and further reduce noise and pressure loss.

  The hermetic compressor of the third invention is the hermetic compressor of the first invention or the second invention, and the planar shape of the opening of the seat portion is an elliptical shape.

  Here, since the planar shape of the opening of the seat part is an elliptical shape, the stress generated in the valve plate is reduced, so that it is possible to further improve the durability of the valve plate and further reduce noise and pressure loss. Become.

  A hermetic compressor according to a fourth aspect of the present invention is the hermetic compressor according to the third aspect of the present invention, and the elliptical ellipticity of the elliptical shape is 0.6 or less.

  Here, since the elliptical oblateness ratio of the elliptical shape is 0.6 or less, it is possible to reliably ensure the fatigue strength of the valve plate even if the flow path area is the same. In addition, it is possible to sufficiently reduce the flow rate of the refrigerant in the seat portion by expanding the flow path area while reliably maintaining the safety factor for the fatigue strength of the valve plate, and further reducing noise and pressure loss. Reduction is possible.

  The hermetic compressor of the fifth invention is the hermetic compressor of the first invention or the second invention, and the planar shape of the opening of the seat portion is a long hole shape.

  Here, since the planar shape of the opening of the seat portion is a long hole shape, it is possible to improve the durability of the valve plate, reduce noise and pressure loss, and easily design and process the opening. Become.

  The hermetic compressor of the sixth invention is the hermetic compressor of the first invention, wherein the refrigerant used is carbon dioxide.

  Here, since the refrigerant used is carbon dioxide, the differential pressure inside and outside the cylinder is larger than that of other refrigerants, but in this case as well, the durability of the valve plate is improved, so the opening area of the seat part Can be increased.

  According to the first invention, the flow passage area can be expanded while maintaining the safety factor of the fatigue strength of the valve plate. Thereby, the flow rate of the refrigerant at the opening of the seat portion can be reduced, and noise and pressure loss can be reduced.

  According to the second invention, since the stress generated in the valve plate is reduced, it is possible to further improve the durability of the valve plate and further reduce noise and pressure loss.

  According to the third invention, since the stress generated in the valve plate is reduced, it is possible to further improve the durability of the valve plate and further reduce noise and pressure loss.

  According to the fourth invention, the fatigue strength of the valve plate can be reliably ensured even if the flow path area is the same. Moreover, by enlarging the flow path area while reliably maintaining the safety factor for the fatigue strength of the valve plate, the flow velocity at the seat portion can be sufficiently reduced, and noise and pressure loss can be further reduced.

According to the fifth aspect, the durability of the valve plate can be improved and noise and pressure loss can be reduced. In addition, the design and processing of the opening is facilitated.
it can.

  According to the sixth aspect of the invention, even if the differential pressure inside and outside the cylinder is larger than that of other refrigerants, the durability of the valve plate is improved, so that the opening area of the seat portion can be increased.

<Overall configuration of hermetic compressor 1>
The hermetic compressor 1 using the CO ₂ refrigerant shown in FIGS. 1 and ₂ as a compression medium includes a casing 2, a motor 3, a compression mechanism 4, and a shaft 6. The motor 3, the compression mechanism 4 and the shaft 6 are accommodated in the casing 2. The compression mechanism 4 is a single-cylinder swing compressor, and has a swinging piston 21, a blade 22, a bush 23, and a cylinder 27, which will be described later.

In the hermetic compressor 1, CO ₂ refrigerant is used as a compression medium. The internal pressure of the casing 2 filled with the CO ₂ refrigerant is high (about 12 MPa), and the differential pressure inside and outside the cylinder 27 applied to the valve plate 36 is higher than that of other refrigerants such as Freon refrigerant. ing.

  The casing 2 has a cylindrical portion 2a and a pair of end plates 2b and 2c that close upper and lower opening ends of the cylindrical portion 2a. The cylindrical portion 2a of the casing 2 houses the cylinder 27, the seat portion 37 (see FIG. 4), and the valve plate 36 of the compression mechanism 4. Further, the cylindrical portion 2 a of the casing 2 accommodates the motor stator 8 and the motor rotor 9 of the motor 3.

  Further, the casing 2 has an oil storage space 32 in which the refrigeration oil A is stored in the lower part of the compression mechanism 4.

  The motor 3 includes an annular motor stator 8 and a motor rotor 9 that is rotatably disposed in an internal space 8 a of the motor stator 8. The motor rotor 9 is connected to the shaft 6 and can rotate with the shaft 6.

  The motor stator 8 is fixed to the cylindrical portion 2a by a plurality of point joints 7. Specifically, the point joint portion 7 is formed by forming a through hole 2d in the cylindrical portion 2a and spot welding the motor stator 8 through the through hole 2d.

<Configuration of compression mechanism 4>
As shown in FIGS. 1 and 2, the compression mechanism 4 includes a swinging piston 21 having a blade 22, a bush 23 that supports the blade 22 in a swingable manner, a cylinder 27, and fronts located at both ends of the cylinder 27. A head 33 and a rear head 34, a valve plate 36, and a seat portion 37 are provided. The cylinder 27 has a cylinder chamber 24 that houses the oscillating piston 21, a bush hole 25 into which the bush 23 is rotatably inserted, and the rear head 34 has a bush oil supply passage 26 that communicates with the bush hole 25. .

The oscillating piston 21 is oscillated inside the cylinder chamber 24 by receiving the rotational driving force of the motor 3 and rotating the eccentric portion 6a of the shaft 6 eccentrically, whereby the CO 2 sucked from the intake pipe 28 is oscillated. _Two refrigerants are compressed inside the cylinder chamber 24. The compressed CO ₂ refrigerant pushes open the valve plate 36 and discharges it into the casing 2 through the discharge port 35, then rises through the inside of the casing 2 and is discharged from the discharge pipe 29.

  The front head 33 is screwed to the mounting plate 30. The mounting plate 30 is fixed to the cylindrical portion 2 a of the casing 2 by a mounting plate joint portion 31. The mounting plate joint 31 is formed by spot welding.

<Configuration of valve plate 36 and seat portion 37>
As shown in FIGS. 1 to 5, the front head 33 above the cylinder 27 includes a discharge port 35, a seat portion 37, and a valve plate 36. The discharge port 35 is a passage through which the refrigerant compressed by the cylinder 27 flows. As shown in FIG. 3, the sheet portion 37 has an opening 37 a (hereinafter, referred to as an opening 37 a) that communicates with the discharge port 35. The valve plate 36 closes the opening 37 a of the seat portion 37 to stop the reverse flow of the refrigerant into the cylinder 27 at the discharge port 35. The valve plate 36 is provided at a position in contact with the periphery of the opening 37 a of the seat portion 37. A discharge valve 40 is constituted by the seat portion 37 and the valve plate 36.

  As shown in FIGS. 3 to 5, the valve plate 36 is a thin plate-like member that can be elastically deformed and bent. One fixed end 36a of the valve plate 36 is fixed to the front head 33 by screws or the like. A closed portion 36 b that is the other free end of the valve plate 36 has a disk shape and covers the opening 37 a of the seat portion 37. When the refrigerant compressed by the cylinder 27 is discharged from the discharge port 35, the valve plate 36 is opened by the discharge pressure of the refrigerant. When the refrigerant is not discharged, the valve plate 36 is closed by the differential pressure F inside and outside the cylinder 27. .

<About the shape of the discharge port 35>
3-5, the planar shape of the opening 37a of the sheet | seat part 37 is non-circular shapes, such as an ellipse. That is, the opening 37a of the sheet portion 37 has an elliptical shape with a longer diameter A1α and a shorter diameter A1β. Here, when compared with the diameter A2 of the circular discharge port 35, A1α>A2> A1β. As a result, it is possible to improve the durability of the valve plate 36 and reduce noise and pressure loss. As will be described later, the elliptical oblateness ratio (A1β / A1α) is set to 0.6 or less so that an improvement in durability and a reduction in noise and pressure loss can be suitably achieved.

  In particular, the planar shape of the opening 37a of the seat portion 37 is a non-circular shape such as an ellipse such that the maximum stress generated when the valve plate 36 is pressed against the seat portion 37 is smaller than in the case of a circular shape. It is possible to further improve the durability of the valve plate 36 and further reduce noise and pressure loss.

In the embodiment, the planar shape of the opening 37a of the sheet portion 37 is an elliptical shape. FIG. 6 is a graph showing the relationship between the elliptic flatness of the opening 37a and the safety factor (with respect to the fatigue strength of the valve plate 36) in three different types of CO ₂ compressors. Three different models (No. 3, 2 and 6) are the CO ₂ compressors described in Table 1. According to FIG. 6, for all three different models, the safety factor when the flatness ratio is 0.6 or less is always higher than the safety factor when the flatness is greater than 0.6.

FIG. 7 shows a graph showing the relationship between the elliptic flatness of the opening 37a and the flow rate of the refrigerant (flow rate at the opening 37a) in three different types of CO ₂ compressors (see Table 1). According to FIG. 7, for all three different models, the flow velocity when the flatness ratio is 0.6 or less is always lower than the flow velocity when the flatness ratio is greater than 0.6.

  As can be seen from the results of the graphs of FIGS. 6 to 7 described above, it is preferable that the elliptical ellipticity of the elliptical shape is preferably set to 0.6 or less. That is, by making the shape of the seat portion 37 a non-circular elliptical shape with a flatness ratio (short axis / long axis) of 0.6 or less, the fatigue strength of the valve plate 36 is reliably ensured even if the flow path area is the same. It becomes possible. In addition, the flow rate of the refrigerant in the seat portion 37 can be sufficiently reduced by expanding the flow path area while reliably maintaining the safety factor (with respect to the fatigue strength of the valve plate 36). It is possible to further improve the durability of 36 and further reduce noise and pressure loss.

<Relationship between seat diameter, flow velocity, noise and safety factor>
For example, in a normal hermetic compressor, as shown in FIG. 8, the larger the seat diameter A <b> 1 that is the diameter of the opening 37 a of the seat portion 37, the slower the flow velocity in the seat portion 37. In order to ensure fatigue strength against tensile stress due to such differential pressure F, the sheet diameter A1 above a certain level could not be increased. Assuming that the port diameter, which is the diameter of the discharge port 35, is A2, in the hermetic compressor for the chlorofluorocarbon refrigerant (R410A), (sheet diameter A1) / (port diameter A2) = (channel ratio E) is 1 While the flow rate ratio E in the closed compressor for CO ₂ refrigerant is about 1.21 to 1.29 (see Table 1), it is about .27 to 1.39 (see Table 1). I cannot help it.

  However, in the hermetic compressor 1 of the present invention, since the planar shape of the opening 37a of the seat portion 37 is a non-circular shape such as an ellipse, the flow path ratio E increases as the seat diameter A1 increases. However, it is possible to ensure the fatigue strength against the tensile stress due to the differential pressure applied to the valve plate 36. Therefore, even in the case of the same seat diameter A1, it is possible to improve the durability of the valve plate 36 and reduce noise and pressure loss.

  For reference, FIG. 9 shows a graph in which the relationship between the seat diameter, the flow velocity, and the noise is calculated by the Light Hill formula. According to the graph of FIG. 9, the flow velocity and the noise are qualitatively inversely proportional to the seat diameter, and it can be seen that the flow velocity and the noise decrease with an increase in the seat diameter.

FIG. 10 is a graph showing the relationship between the seat diameter and the safety factor (of the fatigue strength of the valve plate 36). In the graph of FIG. 10, a curve in the case of a chlorofluorocarbon refrigerant (R410A) and a curve in the case of a CO ₂ refrigerant are shown. A decrease in safety factor due to a decrease in seat diameter A1 is shown. In addition, in FIG. 10, the graph of three measurement results is shown, and from the top, the measurement results under the conditions of the valve thickness t = 0.382 mm and 0.305 mm in the case of the CO ₂ refrigerant, and the CFC refrigerant ( The measurement results under the condition of valve thickness t = 0.406 mm in the case of R410A) are shown. According to the graph of FIG. 10, it can be seen that the safety factor decreases as the seat diameter increases.

  Considering from the experimental results shown in the graphs of FIGS. 9 to 10 described above, the flow velocity in the seat portion 37 is increased in inverse proportion to the decrease in the flow path area of the opening 37a of the seat portion 37, and noise and pressure loss occur. You can see that

<Features>
(1)
In the hermetic compressor 1 of the embodiment, since the planar shape of the opening 37a of the seat portion 37 is noncircular, it is possible to ensure the fatigue strength of the valve plate 36 even if the flow path area is the same. . Thereby, it becomes possible to enlarge a flow path area, maintaining the safety factor of the fatigue strength of the valve plate 36. FIG. As a result, the flow rate of the refrigerant at the opening 37a of the seat portion 37 is reduced, and noise and pressure loss can be reduced.

(2)
In the hermetic compressor 1 of the embodiment, the planar shape of the opening 37a of the seat portion 37 is a non-circular shape in which the maximum stress generated when the valve plate 36 is pressed against the seat portion 37 is smaller than that in the circular shape. It is. For this reason, it is possible to further improve the durability of the valve plate 36 and further reduce noise and pressure loss.

(3)
In the hermetic compressor 1 of the embodiment, since the planar shape of the opening 37a of the seat portion 37 is an elliptical shape, it is possible to further improve the durability of the valve plate 36 and further reduce noise and pressure loss. . Further, since the elliptical opening 37a has a smooth inner peripheral surface, the reduction of the kinetic energy of the refrigerant when passing through the opening 37a is suppressed as compared with other noncircular openings (for example, a rectangular opening). Is possible.

(4)
In the hermetic compressor 1 according to the embodiment, the fatigue strength of the valve plate 36 is ensured even when the flow path area is the same by making the shape of the seat portion 37 a non-circular elliptical shape with a flatness ratio of 0.6 or less. It becomes possible to do. In addition, the flow rate of the refrigerant in the seat portion 37 can be sufficiently reduced by expanding the flow path area while reliably maintaining the safety factor (with respect to the fatigue strength of the valve plate 36). It is possible to further improve the durability of 36 and further reduce noise and pressure loss.

(5)
In the hermetic compressor 1 of the embodiment, the refrigerant used is a CO ₂ refrigerant. The CO ₂ refrigerant has a property that the differential pressure inside and outside the cylinder increases. Also in the case of such a CO ₂ refrigerant, since the durability of the valve plate is improved, the opening area of the seat portion can be increased.

<Modification>
(A)
In the embodiment, the planar shape of the opening 37a of the sheet portion 37 is an elliptical shape, but the present invention is not limited to this. As a modification of the present invention, the planar shape of the opening 37a of the seat portion 37 may be another non-circular shape, for example, a long hole shape. In this case as well, the durability of the valve plate 36 is improved and the noise is increased. And pressure loss can be reduced. In particular, in the case of the long hole-shaped opening 37a, the design and processing of the opening becomes easier than the elliptical opening. Further, the direction of the elongated hole of the opening 37a extends in a direction from the closed portion 36b toward the fixed end 36a, but the present invention is not limited to this, and other directions, for example, the opening 37a in FIG. The direction may be inclined at any angle with respect to the direction of the long hole (right angle, 45 degrees, 30 degrees, etc.).

  The present invention can be applied to any type of compressor as long as it is a hermetic compressor provided with a discharge valve. In addition to the swing type rotary compressor shown in this embodiment, other types of compressors can be used. It is also possible to employ a compression type (for example, rolling piston type) rotary compressor or a compressor other than the rotary compressor.

The longitudinal section of the swing type rotary compressor concerning the embodiment of the hermetic compressor of the present invention. FIG. 2 is a transverse sectional view of the inside of the cylinder of FIG. FIG. 2 is an enlarged cross-sectional view of an opening of a seat portion and a valve plate in FIG. 1. IV-IV sectional view taken on the line of FIG. VV sectional view taken on the line of FIG. The graph which shows the relationship between the elliptical oblateness of the opening of a seat part, and a safety factor. The graph which shows the relationship between the elliptical oblateness of the opening of a sheet | seat part, and the flow velocity. The expanded sectional view of the seat part vicinity which shows the state which the differential pressure inside and outside a cylinder applies to the valve plate in a seat part. The graph which shows the relationship between a seat diameter, flow velocity, and noise. The graph which shows the relationship between a seat diameter and a safety factor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing type compressor 2 Casing 27 Cylinder 35 Discharge port 36 Valve plate 37 Seat part 37a Opening 40 Discharge valve

Claims (6)

A cylinder (27) for compressing the refrigerant;
A discharge port (35) through which the refrigerant compressed by the cylinder (27) flows;
A sheet portion (37) having an opening (37a) communicating with the discharge port (35);
A valve plate (36) provided at a position in contact with the seat portion (37) and stopping the reverse flow of the refrigerant into the cylinder (27) in the discharge port (35);
A casing (2) housing the cylinder (27), a seat portion (37), and a valve plate (36);
With
The planar shape of the opening (37a) of the sheet portion (37) is non-circular.
Hermetic compressor (1). The planar shape of the opening (37a) of the seat portion (37) is a non-circular shape in which the maximum stress generated when the valve plate (36) is pressed against the seat portion (37) is smaller than in the case of a circular shape. Shape,
The hermetic compressor (1) according to claim 1. The hermetic compressor (1) according to claim 1 or 2, wherein a planar shape of the opening (37a) of the seat portion (37) is an elliptical shape. The elliptical oblateness of the elliptical shape is 0.6 or less.
The hermetic compressor (1) according to claim 3. The planar shape of the opening (37a) of the sheet portion (37) is a long hole shape.
The hermetic compressor (1) according to claim 1 or 2. The refrigerant used is carbon dioxide,
The hermetic compressor (1) according to any one of claims 1 to 5.

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