JP2009299523A - Scroll type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll type fluid machine capable of quickly preventing rollover of a movable scroll occurring due to a pressure rise in an intake chamber and stably performing revolving motion of the movable scroll. <P>SOLUTION: This scroll type fluid machine is equipped with the intake chamber 34 to which intake pressure of operating fluid is applied, a back pressure chamber 48 formed by a back face 26b of a mirror plate 26 of the movable scroll 22 and a frame 42, an annular partitioning member 49 for partitioning the back pressure chamber 48 into a high pressure chamber 51 positioned at a radially central side of each of mirror plates 26, 28 and to which discharge pressure of lubricating oil is applied and an intermediate pressure chamber 53 positioned at a radially outer peripheral part side of each of the mirror plates 26, 28 and reduced in pressure than the high pressure chamber 51, and a pressure releasing means 58 for releasing pressure in the intake chamber 34 to the intermediate pressure chamber 53 only when the pressure in the intake chamber 34 is higher than that in the intermediate pressure chamber 53. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scroll type fluid machine, and more particularly, to a scroll type fluid machine suitable for being incorporated in a refrigeration air conditioner or a heat pump type water heater.

  This type of scroll type fluid machine is, for example, a hermetic scroll compressor, which includes a scroll unit composed of a fixed scroll and a movable scroll each having a spiral wrap in pairs on each end plate surface of each end plate. The movable scroll revolves on the frame with respect to the scroll, thereby forming a compression chamber for the working fluid between the laps. The compression chamber reduces the volume toward the center in the radial direction of each end plate. Moving.

The movable scroll is provided with a suction chamber formed by a fixed scroll end plate and a movable scroll end plate surface, and a back pressure chamber formed by a back surface of the movable scroll end plate and a frame. A technique is disclosed in which a plurality of through-holes are provided in the end plate of the scroll to communicate the suction chamber and the back pressure chamber (for example, see Patent Document 1).
In addition, the back pressure chamber is located on the radial center portion side of each end plate, and a high pressure chamber on which the discharge pressure of the working fluid acts and an intermediate portion located on the radially outer peripheral side of each end plate and depressurized from the high pressure chamber. A scroll compressor including an annular partition member that partitions into a pressure chamber is known (see, for example, Patent Document 2).
JP 2002-213370 A JP 2008-8161 A

  By the way, the movable scroll is pressed toward the fixed scroll against the pressure of the suction chamber mainly by the back pressure of the intermediate pressure chamber. However, the opening of the throttle means of the refrigeration circuit is changed at the time of defrosting operation of the refrigerator, for example, or the mist-like working fluid is sucked into the suction chamber by a so-called liquid back phenomenon and sucked. When the liquid working fluid adhering to the outer wall that becomes a high temperature in the chamber is vaporized, the pressure in the suction chamber may rise rapidly and become larger than the pressure in the intermediate pressure chamber. As a result, a rollover phenomenon occurs in which the movable scroll is pressed to the opposite side of the fixed scroll and tilts, and the working fluid in the compression chamber leaks, so that the compressor cannot be operated normally. If this is performed in an unstable manner, there is a risk of causing poor compression and noise in the compressor.

  Therefore, as described in Patent Document 1, it is conceivable to provide a through hole that communicates the suction chamber and the back pressure chamber. However, in this case, the pressure in the back pressure chamber and the suction chamber becomes the same, and the scroll Since the back pressure structure cannot be formed in the unit and the movable scroll cannot be pressed to the fixed scroll side by the back pressure in the back pressure chamber, the orbiting motion of the movable scroll cannot be stably performed.

In Patent Document 1, the pressure in the intermediate pressure chamber located on the radially outer peripheral side of each end plate becomes a problem in order to prevent the overturning phenomenon of the movable scroll. However, as in Patent Document 2, the back pressure chamber is used. Since no special consideration is given to the back pressure structure that partitions the high pressure chamber and the intermediate pressure chamber, the rollover phenomenon of the movable scroll cannot be effectively prevented.
The present invention has been made in view of such a problem, and is a scroll-type fluid capable of quickly preventing the rollover of the movable scroll caused by the pressure increase in the suction chamber and stably performing the revolving orbiting motion of the movable scroll. The purpose is to provide a machine.

  In order to achieve the above object, the scroll type fluid machine according to claim 1 is composed of a fixed scroll and a movable scroll in which spiral wraps are erected in pairs on each end plate surface of each end plate. The movable scroll revolves around the frame to form a compression chamber for the working fluid between the laps, and the compression chamber moves toward the center in the radial direction of each end plate while reducing its volume. A scroll unit, a fixed scroll end plate and a movable scroll end plate surface, a suction chamber on which the working fluid suction pressure acts, a back pressure chamber formed by the rear surface of the end plate of the movable scroll and the frame, The back pressure chamber is located on the radial center side of each end plate, and the high pressure chamber where the discharge pressure of the working fluid acts, and the intermediate pressure that is located on the radially outer peripheral side of each end plate and is decompressed from the high pressure chamber And a partition member of annular partitioning the bets, is characterized by comprising a pressure relief means relieve the pressure in the suction chamber to the intermediate pressure chamber only when the pressure in the suction chamber becomes larger than the pressure of the intermediate pressure chamber.

According to a second aspect of the present invention, in the first aspect, the pressure relief means is formed so as to penetrate the end plate of the movable scroll, and the communication passage that communicates the suction chamber and the intermediate pressure chamber, and the pressure of the suction chamber is It is characterized by comprising a relief valve that communicates with the communication passage when the pressure in the intermediate pressure chamber becomes larger.
Further, in the invention according to claim 3, in claim 2, the opening on the suction chamber side of the communication path opens to the suction chamber for at least half of the time required for one revolution of the movable scroll. It is provided at a position.

  According to the scroll type fluid machine of the first aspect of the present invention, the pressure relief means for releasing the pressure of the suction chamber to the intermediate pressure chamber only when the pressure of the suction chamber becomes larger than the pressure of the intermediate pressure chamber is provided. As a result, the pressure increase in the suction chamber can be applied to the intermediate pressure chamber only when the pressure in the suction chamber becomes larger than the pressure in the intermediate pressure chamber. Revolving and turning motion can be performed stably.

Specifically, according to the second aspect of the present invention, the pressure relief means is formed through the end plate of the movable scroll, the communication passage communicating the suction chamber and the intermediate pressure chamber, and the pressure of the suction chamber When the pressure is higher than the pressure in the intermediate pressure chamber, the relief valve communicates with the communication passage, and the rollover of the movable scroll can be effectively prevented with a simple configuration.
Further, according to the third aspect of the present invention, the opening on the suction chamber side of the communication passage is provided at a position that is open to the suction chamber for more than half of the time required for one revolution of the movable scroll. Thus, even if the communication path is temporarily blocked by the fixed scroll due to the revolving orbiting motion of the movable scroll, it is possible to reliably prevent the movable scroll from overturning.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a hermetic scroll compressor as an example of a scroll type fluid machine according to the present embodiment. The compressor 1 is incorporated in a refrigeration circuit such as a refrigeration air conditioner or a heat pump type hot water heater. It is. The circuit includes a path through which a carbon dioxide refrigerant (hereinafter referred to as a refrigerant), which is an example of a working fluid, circulates. The compressor 1 sucks the refrigerant from the path, compresses the refrigerant, and discharges the refrigerant toward the path.

  The compressor 1 includes a shell 2, and a center shell 4 that forms a cylindrical body of the shell 2 is hermetically fitted with an upper side and a lower side by a top shell 6 and a bottom shell 8, respectively, and the inside of the center shell 4 is hermetically sealed. The discharge pressure of the refrigerant is acting. A suction pipe 10 for sucking the refrigerant taken in from the circuit is connected to the refrigerant suction chamber formed in the center shell 4, and the compressed refrigerant in the shell 2 is sent to the circuit at an appropriate position of the top shell 6. A discharge pipe 12 is connected.

In the center shell 4, a scroll unit 14, an electric motor 16, and a pump unit 18 are accommodated in this order from above, and a rotating shaft 20 is disposed in the electric motor 16, and the rotating shaft 20 is energized by energization of the electric motor 16. Driven by rotation.
The rotary shaft 20 has an upper end connected to the scroll unit 14 and a lower end connected to the pump unit 18, and the rotary shaft 20 is driven to rotate by the electric motor 16, whereby the scroll unit 14 sucks and compresses the refrigerant. And a series of discharge processes.

  Specifically, the scroll unit 14 includes an asymmetric movable scroll 22 and a fixed scroll 24, and the movable scroll 22 includes a mirror plate 26. A mirror plate surface (front surface) 26 a of the mirror plate 26 faces the mirror plate 28 of the fixed scroll 24. On the other hand, a spiral wrap 32 extending toward the end plate 26 is also erected on the end plate surface 28 a of the end plate 28 of the fixed scroll 24.

The wraps 30 and 32 are formed on the basis of a predetermined involute curve, and are arranged in pairs to cooperate with each other, so that the refrigerant from the refrigerant suction chamber 34 to which the suction pipe 10 is connected at the end plate 28. The compression chamber 36 is formed between the wraps 30 and 32.
The suction chamber 34 is formed by the end plate 28 of the fixed scroll 24 and the end plate surface 26 a of the movable scroll 22, and the suction pressure Ps of the refrigerant acts on the suction chamber 34. Due to the movement, the end plate 26, 28 moves while decreasing its volume toward the center in the radial direction.

In order to give the orbiting scroll 22 a revolving orbiting motion, a boss 38 is formed on the back surface 26b side of the end plate 26, and the boss 38 is rotatable to an eccentric shaft 40 integrally formed on the upper end side of the rotary shaft 20 via a bearing. It is supported by. The rotation of the movable scroll 22 is blocked by a rotation blocking pin (not shown).
On the other hand, the fixed scroll 24 is supported and fixed to a main frame 42 fixed to the inside of the center shell 4, and a discharge hole 44 that can communicate with the compression chamber 36 is formed in the central portion of the fixed scroll 24. ing.

On the other hand, the pump unit 18 sucks the lubricating oil stored inside the bottom shell 8, and the sucked lubricating oil passes through an oil passage 46 drilled in the rotating shaft 20 from the upper end of the rotating shaft 20. And is supplied to the scroll unit 14 and the like, and contributes to the lubrication of each sliding portion and bearing, and the sealing and lubrication of the sliding surface.
Specifically, as shown in the enlarged view of the main part of the scroll unit 14 in FIG. 2, the lubricating oil that has passed through the oil passage 46 flows down from the upper end of the rotating shaft 20 toward the electric motor 16 along the rotating shaft 20. It is supplied to a back pressure chamber 48 formed between the back surface 26 b of the end plate 26 of the movable scroll 22 and the main frame 42, and a gap 50 between the outer peripheral surface 26 c of the end plate 26 and the main frame 42 is formed from the back pressure chamber 48. The passed lubricating oil is supplied to the sliding surface 52 that slides on the end plate 26 of the movable scroll 22 with respect to the fixed scroll 24.

  Here, the back pressure chamber 48 is a lubricant for lubricating oil that is positioned on the radial center side of the end plates 26 and 28 through the oil passage 46 by an annular seal ring (partition member) 49 fixed to the main frame 42. Is divided into a high pressure chamber 51 on which the discharge pressure acts and an intermediate pressure chamber 53 located on the radially outer peripheral side of the end plates 26 and 28 and depressurized from the high pressure chamber 51. By forming such a back pressure structure, the movable scroll 22 is appropriately pressed against the fixed scroll 24 mainly by the pressure of the intermediate pressure chamber 53, and the smooth revolving motion of the movable scroll 22 is realized. .

  According to the compressor 1 described above, the revolving and revolving motion of the movable scroll 22 without rotating with the rotation of the rotating shaft 20 causes the refrigerant sucked into the scroll unit 14 via the suction pipe 10 to be compressed. The refrigerant in the compression chamber 36 is compressed while being moved toward the center of the scroll unit 14, is then discharged into the shell 2 through the discharge hole 44, circulates through the shell 2, and then passes through the discharge pipe 12. It is sent out of the compressor 1.

By the way, this embodiment is formed through the end plate 26 of the movable scroll 22, and the communication passage 54 that communicates the suction chamber 34 and the intermediate pressure chamber 53, and the pressure of the suction chamber 34 is higher than the pressure of the intermediate pressure chamber 53. Is larger, a pressure relief mechanism (pressure relief means) 58 including a relief valve 56 communicating with the communication passage 54 is provided.
The relief valve 56 is a check valve including a steel ball 56 a and a spring 56 b having one end connected to the steel ball 56 a, and allows the refrigerant to move from the suction chamber 34 to the intermediate pressure chamber 53. The refrigerant is prevented from moving to the suction chamber 34.

In the communication passage 54, a steel ball support portion 60 for supporting the steel ball 56a is formed on the suction chamber 34 side, and the steel ball 56a is pressed and urged against the steel ball support portion 54a by the spring 56b, thereby the suction chamber. 34 and the intermediate pressure chamber 53 can be completely shut off. On the other hand, a spring retainer 62 that supports the other end of the spring 56 b is formed on the intermediate pressure chamber 53 side of the communication passage 54.
As the spring 56b, a spring having a predetermined elastic coefficient is selected, and the steel ball 56a is spring only when the pressure in the suction chamber 34, that is, the suction pressure Ps becomes larger than the pressure in the intermediate pressure chamber 53, that is, the back pressure Pb. The steel ball support portion 60 is separated from the elastic force of 56b, the refrigerant is allowed to move from the suction chamber 34 to the intermediate pressure chamber 53, and the pressure increase Pr of the suction chamber 34 is allowed to escape to the intermediate pressure chamber 53. It is configured. Specifically, the differential pressure ΔP (ΔP = Pb−Ps) between the suction chamber 34 and the intermediate pressure chamber 53 is normally about 0.5 MPa, for example. If the differential pressure ΔP exceeds 0.5 MPa, The excess pressure increase Pr (Pr = ΔP−0.5 MPa) is released from the suction chamber 34 to the intermediate pressure chamber 53.

  In FIG. 2, the opening 54 a on the suction chamber 34 side of the communication passage 54 is positioned at a position facing the suction chamber 34, but the opening 54 a is also sucked by the revolving orbiting motion of the movable scroll 22. A position that does not extend from the chamber 34 to the compression chamber 36 formed in the vicinity of the suction chamber 34, and at least half of the time required for one revolution of the movable scroll 22 is provided at a position that opens to the suction chamber 34. It is done.

  As described above, the present embodiment includes the pressure relief mechanism 58 that allows the pressure in the suction chamber 34 to escape to the intermediate pressure chamber 53 only when the pressure in the suction chamber 34 becomes larger than the pressure in the intermediate pressure chamber 53. As a result, the pressure increase Pr of the suction chamber 34 can be applied to the intermediate pressure chamber 53 only when the suction pressure Ps becomes larger than the back pressure Pb. The 22 revolution turning motions can be stably performed.

  Specifically, for example, the opening degree of the throttle means of the refrigeration circuit is changed during the defrosting operation of the refrigerator in which the compressor 1 is incorporated, or the mist refrigerant is introduced into the suction chamber 34 by a so-called liquid back phenomenon. The liquid refrigerant adhering to the outer wall, which is sucked and becomes high temperature in the suction chamber 34, is vaporized, so that the suction pressure Ps rises rapidly, and even if the suction pressure Ps becomes larger than the back pressure Pb, the movable scroll 22 is overturned. It is possible to quickly prevent the leakage of the refrigerant from the compression chamber 36, the compression failure, and the noise.

Further, the pressure relief mechanism 58 can effectively prevent the movable scroll 22 from being overturned with a simple configuration including the communication passage 54 and the relief valve 56.
Further, the opening 54a on the suction chamber 34 side of the communication passage 54 is provided at a position where it opens to the suction chamber 34 for more than half of the time required for one revolution of the movable scroll 22 to move. Even if the communication path 54 is temporarily blocked by the fixed scroll 24 by the revolving orbiting motion of 22, the rollover of the movable scroll 22 can be reliably prevented.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the pressure relief mechanism 58 including the communication passage 54 and the relief valve 56 is formed. However, the present invention is not limited to this, and for example, by providing an orifice in the communication passage 54, the suction chamber 34 and the intermediate pressure chamber 53 are provided. Even if a pressure relief mechanism is formed that maintains the differential pressure ΔP with a predetermined value, the rollover of the movable scroll 22 can be effectively prevented in the same manner as described above.

  Moreover, although the said embodiment demonstrated the sealed scroll compressor using the carbon dioxide refrigerant | coolant incorporated in refrigeration circuits, such as a refrigerating air-conditioner and a heat pump type hot water heater, this invention is not limited to this but various operation | movement is demonstrated. The present invention can be applied to a fluid machine using a fluid such as a compressor or an expander in various fields.

1 is a longitudinal sectional view showing a hermetic scroll compressor according to an embodiment of the present invention. It is a principal part enlarged view of the scroll unit of FIG.

Explanation of symbols

1 Hermetic scroll compressor (scroll type fluid machine)
14 scroll unit 22 movable scroll 24 fixed scroll 26 end plate 26a end plate surface 26b rear surface 28 end plate 28a end plate surface 30 wrap 32 wrap 34 suction chamber 36 compression chamber 42 main frame (frame)
48 Back pressure chamber 49 Seal ring (partition member)
51 High Pressure Chamber 53 Intermediate Pressure Chamber 54 Communication Path 54a Opening 56 Relief Valve 58 Pressure Relief Mechanism (Pressure Relief Means)

Claims (3)

Each of the end plates is composed of a fixed scroll and a movable scroll, each of which is provided with a pair of spiral wraps, and the movable scroll revolves on the frame with respect to the fixed scroll. A scroll unit that forms a compression chamber for the working fluid between the laps, and the compression chamber moves toward the radial center of each end plate while reducing its volume;
A suction chamber formed by the end plate of the fixed scroll and the end plate surface of the movable scroll, on which a suction pressure of a working fluid acts;
A back pressure chamber formed by the back surface of the end plate of the movable scroll and the frame;
A high-pressure chamber in which the back pressure chamber is located on the radially central side and the discharge pressure of the working fluid acts, and an intermediate pressure chamber located on the radially outer peripheral side of each end plate and depressurized from the high-pressure chamber And an annular partition member that partitions
A scroll type fluid machine comprising pressure relief means for releasing the pressure of the suction chamber to the intermediate pressure chamber only when the pressure of the suction chamber becomes larger than the pressure of the intermediate pressure chamber.   The pressure relief means is formed through the end plate of the movable scroll, and communicates with the communication passage that communicates the suction chamber and the intermediate pressure chamber, and when the pressure in the suction chamber is greater than the pressure in the intermediate pressure chamber, The scroll fluid machine according to claim 1, comprising a relief valve in communication.   The opening on the suction chamber side of the communication path is provided at a position where it opens to the suction chamber for at least half of the time required for one revolving revolution of the movable scroll. Scroll type fluid machine.

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