JP2008196370A - Fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid machine capable of improving both of productivity and compression efficiency of the fluid machine by simplifying a back pressure regulating mechanism. <P>SOLUTION: The fluid machine is equipped with the back pressure regulating mechanism (96) disposed in an oil passage (24), that forms a back pressure chamber (88) having intermediate pressure lower than the pressure in a high pressure chamber (86) and higher than the pressure in a low pressure chamber (80), and regulates the pressure of the back pressure chamber (88) while supplying lubricating oil from the back pressure chamber (88) to the low pressure chamber (80) according to the pressure in the low pressure chamber (80). The back pressure regulating mechanism (96) includes a communicating groove (92) formed at the front (90) of a movable scroll (52), opened at the outer peripheral side of the movable scroll (52) and recessed toward the low pressure chamber (80) so as to intermittently communicate the back pressure chamber (88) to the low pressure chamber (80) accompanying revolving turning motion of the movable scroll (52). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluid machine, and more particularly, to a fluid machine suitable for a refrigeration air conditioner and a heat pump type hot water heater.

  In this type of fluid machine, for example, a scroll compressor, a scroll unit that performs a series of processes of sucking, compressing and discharging a working fluid is provided in a housing. Specifically, this unit includes fixed and movable scrolls that mesh with each other, and the movable scroll revolves around the axis of the fixed scroll on the frame. Thereby, the volume of the compression chamber formed by each scroll is reduced, and the above-described series of processes is performed.

Here, a back pressure chamber that is decompressed on the back side of the movable scroll by forming an oil passage for the lubricating oil between the back surface of the movable scroll and the frame and further providing a decompression means for restricting the flow path of the oil passage. Techniques for forming are known. The back pressure chamber is intermittently communicated with the refrigerant suction chamber by a back pressure adjusting valve, thereby adjusting the pressure of the back pressure chamber while supplying an appropriate amount of lubricating oil to the suction chamber side, and In addition, a technique for improving the compression efficiency of a compressor by suitably performing lubrication is known.
International Publication No. WO2002 / 061285

However, since the conventional technology requires a back pressure regulating valve, there is a problem that the productivity of the compressor is lowered. This is because the back pressure adjusting valve is composed of a steel ball and a spring that presses the steel ball, which leads to an increase in the number of parts. In addition, the back pressure adjusting valve is built in the end plate of the fixed scroll. This is because the scrolling process becomes complicated.
The present invention has been made in view of such problems, and an object of the present invention is to provide a fluid machine that can simplify the back pressure adjustment mechanism and improve both the productivity and the compression efficiency of the fluid machine. To do.

  In order to achieve the above object, a fluid machine according to claim 1, wherein the fluid machine extends in the housing, is rotatably supported by the housing, and is provided in the housing and is fixed integrally with the housing. A scroll unit that is driven by the scroll and the rotary shaft and revolves around the axis of the fixed scroll and performs a series of processes of suction, compression, and discharge of the working fluid, and is accommodated in the housing A frame that supports the movable scroll so as to be capable of revolving, and a high pressure chamber that is provided in the housing and on which the discharge pressure of the working fluid acts on the axial center side of the rotating shaft, between the back surface of the movable scroll and the frame, And an oil passage configured toward the low-pressure chamber on which the suction pressure of the working fluid acts via the outer peripheral side of the movable scroll, and the high-pressure passage disposed in the oil passage, A back pressure chamber having an intermediate pressure that is lower than that of the low pressure chamber and higher than that of the low pressure chamber, and supplying the lubricating oil from the back pressure chamber to the low pressure chamber according to the pressure of the low pressure chamber. A back pressure adjusting mechanism that adjusts the pressure in the pressure chamber, and the back pressure adjusting mechanism is opened on the outer peripheral side of the movable scroll on the front surface of the movable scroll and is recessed to extend toward the low pressure chamber. It is characterized by including a communication groove for intermittently communicating the back pressure chamber with the low pressure chamber in accordance with the turning motion.

  According to a second aspect of the present invention, in the first aspect, the back pressure adjusting mechanism includes a circumferential groove that is communicated with the communication groove and is recessed concentrically with the substantially center of the movable scroll on the front surface of the movable scroll. Further, the invention according to claim 3 is characterized in that, in claim 1 or 2, the working fluid is a refrigerant composed of carbon dioxide.

  According to the fluid machine of the first aspect of the present invention, the back pressure adjusting mechanism is configured to include a communication groove that intermittently communicates the back pressure chamber with the low pressure chamber in accordance with the revolving turning motion of the movable scroll. The communication groove opens to the outer peripheral side of the movable scroll on the front side of the movable scroll and is recessed to extend toward the low pressure chamber, so that the lubricating oil in the back pressure chamber is directed toward the low pressure chamber according to the pressure in the low pressure chamber. Therefore, the pressure in the back pressure chamber can be adjusted with a simple mechanism. Therefore, the back pressure adjustment mechanism is simplified and the productivity of the fluid machine can be improved while improving the compression efficiency of the fluid machine.

According to the second aspect of the present invention, it further includes a circumferential groove that communicates with the communication groove and is concentrically recessed with the approximate center of the rotation shaft on the front surface of the movable scroll. Lubricating oil can be supplied evenly to the low pressure chamber over the entire circumference of the scroll unit, and the accuracy of the back pressure adjustment mechanism can be improved.
Moreover, this circumferential groove also functions as an oil reservoir for retaining lubricating oil over substantially the entire back pressure chamber, thereby improving the lubricity of the scroll unit and further improving the compression efficiency of the fluid machine. .

  Furthermore, according to the third aspect of the present invention, when a refrigerant composed of carbon dioxide is used as the working fluid, the fluid machine operates at a higher pressure and a higher rotation, so that the productivity and compression efficiency of the fluid machine are maintained. However, the back pressure adjustment mechanism is inevitable. However, according to the above configuration, the back pressure adjusting mechanism can be formed with a simple mechanism while improving both the productivity and compression efficiency of the fluid machine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a hermetic scroll compressor that is an example of a 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. 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 housing 2, and the body 3 of the housing 2 is hermetically fitted with an upper lid 4 and a lower lid 5 on the upper and lower sides, respectively, and the interior of the trunk 3 is sealed, The discharge pressure is acting.
An electric motor 6 is accommodated in the body 3, and a rotating shaft 12 is disposed in the motor 6. Specifically, in the motor 6, a rotor 7 having a permanent magnet is fixed to the outer peripheral side of the rotating shaft 12, and a stator 8 having an armature winding 9 is disposed on the outer peripheral side of the rotor 7. A part of the outer peripheral side of the stator 8 is press-fitted and fixed to the body 3. When the armature winding 9 is energized, the rotor 7 is rotated by the magnetic field generated by the armature winding 9 and rotates integrally with the rotary shaft 12. Further, the upper end side of the rotary shaft 12 is rotatably supported by a main spindle frame (frame) 14 via a bearing 16.

  On the other hand, the lower end side of the rotating shaft 12 is rotatably supported by the countershaft frame 18 via the bearing 20. An oil pump 22 is attached to the lower end side of the rotary shaft 12, and the pump 22 sucks lubricating oil in an oil storage chamber 23 formed inside the lower lid 5. The lubricating oil is supplied from the upper end of the rotating shaft 12 to the motor 6 and the scroll unit 30 through the oil passage 24 of the rotating shaft 12, and functions as a lubricant for each sliding portion and a bearing and a seal for the sliding surface. . Further, an inlet 19 for lubricating oil is formed at an appropriate position of the frame 18, and the lubricating oil supplied to each sliding portion in the compressor 1 is stored in the oil storage chamber via the inlet 19 as will be described later. 23 is stored.

  The unit 30 is disposed above the motor 6 in the body 3, and performs a series of processes of refrigerant suction, compression, and discharge. Specifically, the unit 30 includes a movable scroll 52 and a fixed scroll 32, and the movable scroll 52 includes an end plate 54. The end plate 54 has a spiral wrap extending toward the end plate 34 of the fixed scroll 32. Is formed. On the other hand, a spiral wrap extending toward the end plate 54 is also integrally formed on the end plate 34 of the fixed scroll 32. And each of these spiral wraps cooperate with each other to form a compression chamber, and this compression chamber moves from the radially outer peripheral side of the spiral wrap toward the center by the revolving orbiting motion of the movable scroll 52 relative to the fixed scroll 32, At this time, the volume is reduced.

A boss 68 is formed on the lower surface side of the end plate 54 in order to impart a revolving orbiting motion to the movable scroll 52 described above, and this boss 68 is rotatably supported on the eccentric shaft 26 via a bearing 28. The eccentric shaft 26 is integrally formed on the upper end side of the rotary shaft 12. The rotation of the movable scroll 52 is prevented by a rotation prevention pin (not shown).
On the other hand, the fixed scroll 32 is fixed to the spindle frame 14, and the end plate 34 partitions the compression chamber side and the discharge chamber 60 side. A discharge hole 62 communicating with the compression chamber side is formed at an appropriate position in the central portion of the fixed scroll 32 so as to penetrate the end plate 34, and this discharge hole 62 is disposed on the non-scroll side of the fixed scroll 32. The discharge valve 64 is opened and closed. Further, the non-scroll side of the fixed scroll 32 including the discharge valve 64 is covered with a discharge head 66, and the sound when the discharge valve 64 is opened is suppressed by the discharge head 66.

According to the compressor 1 described above, as the rotary shaft 12 rotates, the movable scroll 52 revolves without rotating. The revolving orbiting motion of the movable scroll 52 causes the refrigerant taken into the body portion 3 through the suction pipe 70 to be sucked from the outer peripheral side of the unit 30 toward the inside thereof.
When the volume of the compression chamber is reduced, the compressed high-pressure refrigerant is discharged from the discharge hole 62, circulates in the housing 2, reaches the discharge chamber 60, and is sent out of the compressor 1 through the discharge pipe 72.

On the other hand, the high-pressure lubricating oil pumped up by the pump 22 in combination with the action of the discharge pressure of the refrigerant is supplied to the bearing 28 from the upper end of the rotating shaft 12, and then moves inside the housing 2 along the rotating shaft 16. While flowing down, it is supplied to the unit 30.
Specifically, as shown in an enlarged view in FIG. 2, a space 76 exists between the back surface 74 of the movable scroll 52 and the spindle frame 14, and the high-pressure lubricating oil is on the outer periphery side of the space 76 and the movable scroll 52. The air is supplied toward the compression chamber in the unit 30 through the space 78 and the suction chamber (low pressure chamber) 80 to which the suction pipe 70 is connected. That is, the spaces 76 and 78 function as an oil guiding path that guides the lubricating oil supplied from the oil path 24 to the inside of the unit 30.

  The space 76 is partitioned by an annular seal ring 82, and this ring 82 is fitted and supported in a seal ring groove 84 provided in the spindle frame 14. On the other hand, a long groove 85 extending in the radial direction of the movable scroll 52 is formed in the back surface 74 of the movable scroll 52. As the revolving orbiting movement of the movable scroll 52 is performed, the long groove 85 is intermittently positioned across the ring 82, so that the inner peripheral side and the outer peripheral side of the ring 82 are intermittently communicated, and the outer peripheral side of the ring 82 Is supplied with lubricating oil. As a result, a high pressure chamber 86 made of high pressure lubricating oil is formed on the inner peripheral side of the ring 82 in the space 76, and the outer peripheral side of the ring 82 and the space 78 in the space 76 are decompressed from the high pressure chamber 86. A back pressure chamber 88 of the movable scroll 52 is formed. A plurality of long grooves 85 may be provided.

Incidentally, an oil supply groove (communication groove) 92 for intermittently communicating the back pressure chamber 88 and the suction chamber 80 with the revolution turning motion of the movable scroll 52 is formed in the front 90 of the movable scroll 52.
The oil supply groove 92 is a long groove cut out from the space 78 toward the suction chamber 80 toward the approximate center of the movable scroll 52, and opens into the space 78, that is, the back pressure chamber 88. The groove width and groove depth of the oil supply groove 92 are set in advance according to the refrigerant suction pressure and the fluctuation range of the suction pressure in the compressor 1, so that the back pressure chamber 88 is in the entire operation region of the compressor 1. The pressure in the back pressure chamber 88, that is, the back pressure is maintained in a pressure range lower than the pressure in the high pressure chamber 86 and the pressure in the suction chamber 80, that is, an intermediate pressure higher than the suction pressure.

  Further, as shown in FIG. 3, the refueling groove 92 is disconnected when the revolving turning motion of the movable scroll 52 proceeds from the state shown in FIGS. 2 to 3, and again when the revolving turning motion of the movable scroll 52 advances. The groove length is set in advance so as to return to the state of FIG. Accordingly, the back pressure chamber 88 and the suction chamber 80 are intermittently communicated with the revolving turning motion of the movable scroll 52, and the oil supply groove 92 cooperates with the ring 82 to adjust the back pressure of the movable scroll 52. It functions as an adjustment mechanism 96.

  Further, as shown in the front view of the movable scroll 52 in FIG. 4, a circumferential groove 94 is formed in the front 90 so as to be concentric with the approximate center of the movable scroll 52. The circumferential groove 94 is positioned substantially orthogonal to the oil supply groove 92, communicates with the oil supply groove 92, and functions as a part of the back pressure adjustment mechanism 96. Preferably, the groove depth of the circumferential groove 94 is It is formed deeper than the groove depth of the oil supply groove 92.

  As described above, according to this embodiment, the back pressure adjusting mechanism 96 includes the oil supply groove 92 and the circumferential groove 94 that intermittently communicate the back pressure chamber 88 with the suction chamber 80 as the movable scroll 52 rotates orbits. It is comprised including. Since the groove width and groove depth of the oil supply groove 92 are preset according to the refrigerant suction pressure and the pressure fluctuation width in the compressor 1, the oil supply groove 92 adjusts the amount of lubricating oil in the operating state of the unit 30. In other words, it functions as an orifice hole.

  Specifically, the oil supply groove 92 lubricates the back pressure chamber 88 in accordance with the pressure of the suction chamber 80, that is, the suction pressure of the refrigerant, so as to reduce the pressure of the back pressure chamber 88 when the pressure of the suction chamber 80 decreases. Oil is supplied toward the suction chamber 80. Thereby, the pressure of the back pressure chamber 88 can be adjusted by a simple mechanism without requiring processing such as incorporating a back pressure adjusting valve made up of a plurality of parts into the fixed scroll 32, and the back pressure chamber 88 can be combined with the high pressure chamber 86. The intermediate pressure between the suction chamber 80 and the suction chamber 80 can be maintained. Therefore, the back pressure adjusting mechanism 96 is simplified and the productivity of the compressor 1 can be improved while improving the compression efficiency of the compressor 1.

Further, since the back pressure adjusting mechanism 96 includes the circumferential groove 94, the lubricating oil from the back pressure chamber 88 can be supplied to the low pressure chamber 80 side evenly over the entire circumference of the scroll unit. The accuracy as the back pressure adjusting mechanism 96 can be improved.
Moreover, the circumferential groove 94 also functions as an oil reservoir for retaining the lubricating oil over substantially the entire area of the back pressure chamber. In particular, the circumferential groove 94 is formed deeper than the oil supply groove 92. By doing so, the lubricity of the unit 30 can be improved without obstructing the function of the oil supply groove 92, and as a result, the compression efficiency of the compressor 1 can be further improved.

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, although the scroll compressor has been described in the above embodiment, the scroll compressor may be used for an expander or the like as long as a series of refrigerant suction, compression, and discharge processes is performed.
Moreover, in the said embodiment, although carbon dioxide is used as a refrigerant | coolant, it is not limited to this. However, when carbon dioxide is used as the refrigerant, the compressor operates at a higher pressure and higher rotation, so that the back pressure adjustment mechanism is inevitably increased in order to maintain the productivity and compression efficiency of the compressor. However, according to the above configuration, the back pressure adjusting mechanism 96 can be formed with a simple mechanism while improving both the productivity and the compression efficiency of the compressor 1.

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 FIG. It is the figure which showed the state which the revolution turning motion of the movable scroll advanced from FIG. It is the figure which showed the front of the movable scroll of FIG.

Explanation of symbols

1 Hermetic compressor (fluid machine)
2 Housing 12 Rotating shaft 14 Spindle frame (frame)
24 oil passage 30 scroll unit 32 fixed scroll 52 movable scroll 74 back surface 80 suction chamber (low pressure chamber)
86 High-pressure chamber 88 Back-pressure chamber 90 Front 92 Lubrication groove (communication groove)
94 Circumferential groove 96 Back pressure adjustment mechanism

Claims (3)

A rotating shaft extending through the housing and rotatably supported by the housing;
A fixed scroll provided in the housing and integrally provided with the housing, and a movable scroll driven by the rotating shaft and revolving around the axis of the fixed scroll, and sucking and compressing working fluid And a scroll unit for performing a series of discharge processes;
A frame that is housed in the housing and supports the orbiting scroll so as to be capable of revolving and turning;
The working fluid is provided in the housing and from the high-pressure chamber where the discharge pressure of the working fluid acts on the axis side of the rotating shaft, between the back surface of the movable scroll and the frame, and through the outer peripheral side of the movable scroll. An oil passage configured toward a low pressure chamber on which a suction pressure of
A back pressure chamber that is disposed in the oil passage and forms an intermediate pressure that is lower than the pressure of the high pressure chamber and higher than the pressure of the low pressure chamber is formed from the back pressure chamber to the low pressure chamber according to the pressure of the low pressure chamber. A back pressure adjusting mechanism that adjusts the pressure of the back pressure chamber while supplying lubricating oil toward the
The back pressure adjusting mechanism is opened in front of the movable scroll on the outer peripheral side of the movable scroll and is recessed to extend toward the low pressure chamber, and the back pressure chamber is moved to the low pressure as the movable scroll revolves. A fluid machine comprising a communication groove for intermittently communicating with a chamber.   The back pressure adjusting mechanism further includes a circumferential groove that communicates with the communication groove and is recessed concentrically with a substantially center of the movable scroll in front of the movable scroll. Fluid machine.   The fluid machine according to claim 1, wherein the working fluid is a refrigerant made of carbon dioxide.

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