JP2010043598A - Scroll type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll type fluid machine preventing a movable scroll from overturning by properly retaining the back pressure of the movable scroll with a simple configuration. <P>SOLUTION: A back pressure adjusting valve (70) that can adjust the pressure in a back pressure chamber is interposed in communication passages (80a, 80b) connecting the back pressure chamber (46) behind the movable scroll (34) with a compression chamber (39) so that the pressure in the back pressure chamber becomes larger than that in the compression chamber by predetermined differential pressure. The communication passage (80b) is communicated with the compression chamber at a predetermined position advanced in compression compared to an intake chamber (37) of working fluid. <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 a refrigeration air conditioner and a heat pump type water heater.

  In this type of scroll type fluid machine, a scroll unit that performs a series of processes of refrigerant suction, compression, and discharge is provided in a container. Specifically, this unit includes fixed and movable scrolls that mesh with each other. A boss is formed on the back surface of the movable scroll, and a crank pin that is integrally formed with the rotating shaft is connected to the boss. When the movable scroll is driven by the rotating shaft through the boss, the movable scroll revolves around the axis of the fixed scroll while being supported by the spindle frame without rotating. Thereby, the capacity of the space formed between the spiral wraps of each scroll is reduced, and the above-described series of processes is performed.

By the way, in such a scroll type fluid machine, it is important to securely mesh the spiral wraps of the scrolls and to seal the space formed between the spiral wraps to prevent refrigerant leakage.
However, there is a case where the movable scroll is pulled away from the fixed scroll due to a sudden rise in the refrigerant suction pressure, and the movable scroll is tilted and overturned. There is a problem that a gap is generated, and the sealed state of the space cannot be sufficiently maintained.

In view of this, an apparatus having a configuration in which the back pressure of the movable scroll can be maintained high is known in order to keep the space between the spiral wraps in a sealed state (see Patent Documents 1 and 2).
JP 2006-9640 A JP-A-3-258985

However, in the technique disclosed in Patent Document 1, the pressure in the back pressure space is set to a constant pressure difference with respect to the pressure in the suction chamber in the compression chamber, and the pressure in the suction chamber increases rapidly. However, there is a problem that overturning occurs due to insufficient back pressure, compressed gas inside the compression chamber leaks, and compression failure and noise occur.
Moreover, in the technique disclosed in Patent Document 2, the back pressure regulating valve is electrically controlled, which makes the configuration complicated and is not preferable.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a scroll that has a simple configuration and can appropriately hold the back pressure of the movable scroll and prevent the movable scroll from overturning. It is to provide a mold fluid machine.

  In order to achieve the above object, a scroll type fluid machine according to claim 1 includes a rotating shaft that extends in a container and is rotatably supported by the container, and a crank that is integrally formed eccentrically on the upper end side of the rotating shaft. A pin, a fixed scroll provided in the container, and a movable scroll that revolves around the axis of the fixed scroll by being connected to the crankpin and driven by the rotary shaft; A scroll unit that performs a series of processes of suction, compression, and discharge of working fluid while reducing the volume of a compression chamber formed by meshing the spiral wrap of the fixed scroll and the spiral wrap of the movable scroll as it moves toward the axis. A spindle frame including a bearing that is accommodated in the container and supports the rotating shaft, an upper surface of the spindle frame, and the movable scroll A back pressure chamber that is formed between the back pressure chamber and the pressure plate and is filled with a lubricating oil, a communication passage that communicates the back pressure chamber and the compression chamber, and is provided in the communication passage. And a back pressure adjusting valve capable of adjusting the pressure in the back pressure chamber so that the pressure in the back pressure chamber becomes a predetermined differential pressure larger than the pressure in the compression chamber, and the communication passage is sucked in the working fluid. The compression chamber communicates with the compression chamber at a predetermined position where the compression proceeds more than the position at which the compression chamber is located.

The scroll type fluid machine according to claim 2 is characterized in that, in claim 1, the communication path extends in the fixed scroll, and the back pressure adjusting valve is disposed in the fixed scroll.
According to a third aspect of the present invention, in the scroll type fluid machine according to the first or second aspect, the back pressure adjusting valve has one side communicating with the compression chamber via the communication passage and the other side having an inverted conical tapered surface. A cylinder that is reduced in diameter and communicates with the back pressure chamber, a ball that is inserted into the cylinder so as to contact the tapered surface, and a spring that biases the ball toward the tapered surface. A portion of the inner wall that is in contact with the ball on at least the tapered surface is subjected to a manganese phosphate coating treatment.

According to the scroll type fluid machine of the first aspect, the compression chamber formed by revolving and turning the movable scroll with respect to the fixed scroll communicates with the back pressure chamber formed on the back surface of the movable scroll and the back pressure adjusting valve. Although communicated by a passage, the communication passage communicates with the compression chamber at a predetermined position where the compression has progressed more than the position at which the working fluid is sucked.
Therefore, since the pressure in the back pressure chamber is adjusted based on the pressure difference with the pressure in the compression chamber in the compression process, the pressure in the back pressure chamber can be kept relatively high and balanced, and the suction pressure of the working fluid can be reduced. Even if it suddenly rises, the influence of the suction pressure can be reduced, and the movable scroll can be sufficiently pressed to the fixed scroll side by the pressure in the back pressure chamber, and the rollover of the movable scroll can be prevented. .

By preventing the movable scroll from overturning in this way, there is no leakage of compressed gas from the compression chamber, and compression failure can be prevented.
According to the scroll type fluid machine of the second aspect, since the communication path and the back pressure adjustment valve are provided in the fixed scroll, the communication path and the back pressure adjustment valve are not provided separately, and the configuration is simplified. The pressure in the back pressure chamber can be easily maintained relatively high, and the movable scroll can be prevented from overturning.

  According to the scroll type fluid machine of the third aspect, the back pressure adjusting valve is configured such that the ball is urged by the spring toward the tapered surface of the cylinder, and the pressure of the back pressure chamber is the pressure of the compression chamber. If the pressure is smaller than the sum of the pressure and the biasing force of the spring, the valve is held closed.If the pressure in the back pressure chamber becomes larger than the sum of the pressure in the compression chamber and the biasing force of the spring, the ball resists the biasing force of the spring. However, since the portion that contacts the ball of the tapered surface is treated with manganese phosphate coating, the surface roughness of the portion that contacts the ball of the tapered surface is improved. As a result, smoothness is achieved, and the sealing performance when the back pressure adjustment valve is closed is improved.

  As a result, for example, the compressed gas in the compression chamber can be prevented from leaking into the back pressure chamber, and compression failure can be further prevented.

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

  As shown in the figure, the compressor 1 includes a housing (container) 2, and the body 4 of the housing 2 is airtightly fitted with an upper lid 6 and a lower lid 8 on the upper side and the lower side, respectively. The inside of the part 4 is sealed, and a high discharge pressure is acting. Further, a suction pipe 10 for sucking refrigerant taken in from the circuit is connected to the body 4, and a discharge pipe 12 for sending compressed refrigerant in the housing 2 to the circuit is connected to an appropriate position of the upper lid 6. Yes.

An electric motor 14 is accommodated in the body 4, and a rotating shaft 16 is disposed in the motor 14. The rotating shaft 16 is driven by energization of the motor 14. Further, the upper end side of the rotating shaft 16 is rotatably supported by the spindle frame 18 via a bearing 17.
On the other hand, the lower end side of the rotating shaft 16 is rotatably supported by the countershaft frame 22 via the bearing 20. An oil pump 24 is mounted on the lower end side of the rotary shaft 16, and the pump 24 sucks the lubricating oil L in the oil storage chamber 26 formed inside the lower lid 8, that is, at the bottom of the housing 2. The lubricating oil L functions as a lubricant for each sliding portion and a bearing, and a seal for the sliding surface through an oil supply passage 28 formed along the axis inside the rotating shaft 16.

Note that the discharge pressure of the refrigerant acts on the oil level of the lubricating oil L in the oil storage chamber 26, and that the discharge pressure of the refrigerant acts on the oil level of the lubricating oil L also increases the lubricating oil L in the oil supply passage 28. Contribute to. As a result, the outlet of the oil supply passage 28 becomes a high pressure environment substantially equal to the refrigerant discharge pressure.
An inlet 32 for lubricating oil L is formed at an appropriate position of the countershaft frame 22, and the lubricating oil L supplied to each sliding portion in the compressor 1 is stored in the oil storage chamber via the inlet 32. 26 is stored.

The scroll unit 30 is disposed above the motor 14 in the body 4 and performs a series of processes of refrigerant suction, compression, and discharge.
Specifically, the scroll unit 30 is composed of a movable scroll 34 and a fixed scroll 36, and the scrolls 34, 36 are respectively provided with spiral wraps 34 a, 36 a on the opposing surfaces, respectively, and these spiral wraps. A compression chamber 39 is formed between 34a and 36a. As a result, when the movable scroll 34 orbits with respect to the fixed scroll 36, the spiral wraps 34 a and 36 a mesh with each other and cooperate with each other through the suction pipe 10 from the suction chamber 37 formed on the outer peripheral side of the movable scroll 34. The refrigerant is sucked into the compression chamber 39, the volume of the compression chamber 39 is reduced while the compression chamber 39 moves toward the center (axial center) of the spiral wraps 34a and 36a, and the refrigerant is compressed.

  Specifically, when the orbiting scroll 34 orbits, the side surfaces of the spiral wraps 34a and 36a mesh with each other with a minute gap, and the top surface of the spiral wrap 34a, the end plate surface of the fixed scroll 36, the top surface of the spiral wrap 36a and the movable scroll. The volume of the compression chamber 39 decreases while the end plate surfaces of the 34 mesh with each other with a minute gap, and a series of refrigerant suction, compression, and discharge processes is performed.

  In order to impart a turning motion to the movable scroll 34 described above, a boss 38 is formed on the rear surface 34 b of the movable scroll 34 so as to project, and this boss 38 is connected to a crank pin 42 via a bearing 44. The crank pin 42 is integrally formed on the upper end side of the rotating shaft 16, and causes the movable scroll 34 to make a revolving orbiting motion on the spindle frame 18 as the rotating shaft 16 rotates. The rotation of the movable scroll 34 is prevented by the rotation prevention pin 62. The pin 62 protrudes from the back surface 34 b of the movable scroll 34 and is loosely fitted in a bottomed hole 64 formed in the spindle frame 18, and a rotation prevention mechanism 60 is formed. Specifically, the rotation prevention mechanism 60 includes, for example, four sets of pins 62 and holes 64.

The fixed scroll 36 is fixed to the spindle frame 18 and partitions the discharge chamber 54 side and the compression chamber 39 side formed in the upper lid 6. Specifically, a cylindrical outer peripheral wall 19 concentrically with the rotary shaft 16 extends toward the fixed scroll 36 on the main spindle frame 18, and the fixed scroll 36 is joined to the upper edge of the outer peripheral wall 19.
As described above, the fixed scroll 36 is joined to the upper edge of the outer peripheral wall 19, so that a swivel sliding region in which the movable scroll 34 slides is formed between the fixed scroll 36 and the spindle frame 18. Yes. A gap 45 is formed in a portion other than the sliding contact of the movable scroll 34 that is in sliding contact with the outer peripheral wall 19 between the back surface 34b of the movable scroll 34 and the spindle frame 18 in the orbiting sliding region.

The gap 45 constitutes a back pressure chamber 46, and the back pressure chamber 46 is filled with high-pressure lubricating oil L discharged from the outlet of the oil supply passage 28. Therefore, the back pressure chamber 46 presses the movable scroll 34 toward the fixed scroll 36 with the pressure of the lubricating oil L as the back pressure. Thereby, the sealing property of the compression chamber 39 is ensured, and it is possible to prevent a compression failure.
The fixed scroll 36 includes a back pressure adjustment valve 70. Further, the fixed scroll 36 is provided with communication passages 80a and 80b extending from the back surface 36b.

One end of the communication path 80a communicates with one side of the back pressure regulating valve 70, one end of the communication path 80b communicates with the compression chamber 39, and the other end of each of the communication paths 80a, 80b is closed by a discharge head 50 described later. It is peeling off. That is, one side of the back pressure adjustment valve 70 communicates with the compression chamber 39 via the communication passages 80a and 80b. On the other hand, the other side of the back pressure adjusting valve 70 communicates with the back pressure chamber 46.
Specifically, as shown in FIG. 2 in a cross-section along line AA in FIG. 1, the communication path 80b is a first turn of the movable scroll 34 in which one end of the communication path 80b is more compressed than the suction chamber 37. A predetermined position is provided to communicate with the compression chamber 39.

  As shown in FIG. 3 which is a longitudinal section taken along line BB in FIG. 2, the back pressure adjusting valve 70 has a tapered surface 79 and a tapered surface 79 in the cylinder 78 having a reverse conical tapered surface 79. A ball 72 is inserted so as to come into contact, and the ball 72 is biased toward the tapered surface 79 by a spring 74. Specifically, the upper end opening of the cylinder 78 is closed by a plug member 76, and a spring 74 is contracted between the plug member 76 and the ball 72.

  As a result, the back pressure adjusting valve 70 has the sum of the pressure of the compression chamber 39 and the biasing force of the spring 74 supplied to one side of the back pressure adjusting valve 70 via the communication passages 80a and 80b. Under a situation where the pressure is greater than the pressure, the ball 72 is held in a closed state by abutting against the tapered surface 79 by the biasing force of the spring 74, while the compression chamber 39 supplied to one side of the back pressure adjusting valve 70. When the pressure in the back pressure chamber 46 becomes larger than the sum of the pressure and the urging force of the spring 74, the ball 72 is pressed against the urging force of the spring 74 and opens away from the tapered surface 79.

That is, the back pressure adjusting valve 70 is more than the pressure of the compression chamber 39 in which the pressure in the back pressure chamber 46 is always supplied to one side of the back pressure adjusting valve 70 via the communication passages 80a and 80b. In other words, the pressure in the back pressure chamber 46 can be adjusted so that the pressure in the back pressure chamber 46 becomes larger by a predetermined differential pressure than the pressure in the compression chamber 39 in the compression process.
Further, at least a portion of the inner wall of the cylinder 78 of the back pressure regulating valve 70 with which the ball 72 of the tapered surface 79 comes into contact is subjected to a rubrite process (manganese phosphate coating process).

A discharge hole 56 communicating with the compression chamber 39 side is formed at an appropriate position in the central portion of the fixed scroll 36, and the discharge hole 56 is a discharge valve disposed on the back surface 36 b side of the fixed scroll 36. Opened and closed by 58. Further, the discharge valve 58 is covered with the discharge head 50, and the sound when the discharge valve 58 is opened is suppressed by the discharge head 50.
The fixed scroll 36 and the spindle frame 18 have a refrigerant passage (not shown) located in the outer peripheral portion and extending in the axial direction. Thus, although the description is omitted in detail, the refrigerant discharged from the discharge hole 56 can circulate in the housing 2 through the refrigerant passage.

Hereinafter, an operation of the scroll type fluid machine according to the present invention configured as described above will be described.
According to the compressor 1 described above, when the rotating shaft 16 is rotated by the electric motor 14, the movable scroll 34 starts a revolving orbiting motion. The revolving orbiting motion of the movable scroll 34 sucks the refrigerant from the suction pipe 10 toward the inside of the scroll unit 30 and compresses the refrigerant while reducing the volume of the compression chamber. The high-pressure refrigerant compressed in this manner is discharged from the discharge hole 56 and circulates while separating the lubricating oil L in the housing 2, and is then sent out of the compressor from the discharge chamber 54 through the discharge pipe 12.

  At this time, when the pressure in the back pressure chamber 46 becomes higher than the pressure in the compression chamber 39 supplied to one side of the back pressure adjustment valve 70, the back pressure adjustment valve 70 causes the ball 72 to bias the spring 74 by the pressure difference. It is pushed upward against the valve to open the valve. As a result, the back pressure chamber 46 communicates with the compression chamber 39 via the communication passages 80a and 80b, so that the pressure in the back pressure chamber 46 becomes larger by a predetermined differential pressure than the pressure in the compression chamber 39 in the compression process. It is regulated.

  As described above, according to the scroll type fluid machine of the present invention, the communication passage 80 b is drilled so that one end thereof communicates with the compression chamber 39 at a predetermined position of the first turn of the movable scroll 34 that is more compressed than the suction chamber 37. By being provided, the pressure of the back pressure chamber 46 is adjusted with respect to the pressure of the compression chamber 39 in the compression process, and the pressure of the back pressure chamber 46 is relatively high and balanced to be kept appropriate. As a result, even when the suction pressure in the suction chamber 37 increases rapidly and the load applied to the movable scroll 34 on the suction chamber 37 side increases, the influence of the suction pressure applied to the entire movable scroll 34 is reduced. Thus, the movable scroll 34 can be sufficiently pressed toward the fixed scroll 36 by the pressure in the back pressure chamber 46.

That is, a simple configuration is maintained in which the pressure in the communication passages 80a and 80b is higher than the pressure in the suction chamber 37, and the pressure in the back pressure chamber 46 is higher than the pressure in the communication passages 80a and 80b. Therefore, the back pressure deficiency can be eliminated.
Thereby, the rollover of the movable scroll 34 can be prevented, the leakage of the compressed gas from the compression chamber 39 caused by the rollover is eliminated, and the compression failure can be prevented.

  Further, the surface roughness of the portion of the tapered surface 79 where the ball 72 abuts is reduced by performing a lube light treatment on at least the portion of the inner wall of the cylinder 78 of the back pressure adjusting valve 70 where the ball 72 of the tapered surface 79 abuts. It can be improved and smooth. Thereby, the sealing property between the taper surface 79 and the ball 72 when the back pressure adjusting valve 70 is closed is improved, and for example, the compressed gas in the compression chamber 39 can be prevented from leaking into the back pressure chamber 46. Further, it is possible to prevent further compression failure.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the back pressure adjusting valve 70 is configured to press the ball 72 toward the tapered surface 79 with the spring 74. However, the back pressure adjusting valve 70 has the same function and does not impair the features of the present invention. The regulating valve 70 is not limited to the above configuration.

  Furthermore, although the said embodiment demonstrated the sealed scroll compressor incorporated in refrigeration circuits, such as a refrigeration air conditioner and a heat pump type water heater, it is not restricted to this and compressors or expansion other than a sealed type in various fields | areas It is applicable to a scroll type fluid machine such as a machine.

It is a longitudinal section of a scroll type fluid machine concerning an embodiment of the present invention. It is a cross-sectional view which follows the AA line of FIG. It is a longitudinal cross-sectional view which follows the BB line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scroll compressor 2 Housing 34 Movable scroll 36 Fixed scroll 37 Suction chamber 39 Compression chamber 46 Back pressure chamber 70 Back pressure adjustment valve 72 Ball 74 Spring 76 Plug member 78 Cylinder 79 Tapered surface 80a, 80b Communication path

Claims (3)

A rotating shaft extending through the container and rotatably supported by the container;
A crank pin that is eccentrically formed integrally with the upper end side of the rotating shaft;
A fixed scroll; and a movable scroll that revolves around an axis of the fixed scroll by being connected to the crank pin and driven by the rotating shaft. A scroll unit that performs a series of processes of suction, compression, and discharge of the working fluid while reducing the volume of the compression chamber formed by meshing the spiral wrap of the movable scroll and the spiral wrap of the movable scroll as it moves toward the axis.
A main shaft frame including a bearing housed in the container and supporting the rotating shaft;
A back pressure chamber formed between the upper surface of the spindle frame and the end plate surface of the movable scroll, and filled with a lubricating oil under pressure;
A communication path communicating the back pressure chamber and the compression chamber;
A back pressure adjusting valve that is interposed in the communication path and that can adjust the pressure of the back pressure chamber so that the pressure of the back pressure chamber becomes a predetermined differential pressure larger than the pressure of the compression chamber;
The scroll fluid machine according to claim 1, wherein the communication passage communicates with the compression chamber at a predetermined position where the compression is advanced from a position where the working fluid is sucked.   The scroll type fluid machine according to claim 1, wherein the communication path extends in the fixed scroll, and the back pressure adjusting valve is disposed in the fixed scroll. The back pressure adjusting valve has one side communicating with the compression chamber via the communication passage and the other side having a reverse conical tapered surface and having a reduced diameter and communicating with the back pressure chamber; A ball inserted so as to contact the tapered surface, and a spring for biasing the ball toward the tapered surface,
3. The scroll type fluid machine according to claim 1, wherein at least a portion of the inner wall of the cylinder that contacts the ball of the tapered surface is subjected to a manganese phosphate coating treatment. 4.

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