JP2008121481A - Scroll fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve efficiency of a scroll fluid machine by reducing distortion thereof. <P>SOLUTION: A seal member 5 is arranged between a top end surface of a turning boss portion having a bearing part on a counter-lap side of a turning scroll 13 and a central end surface of a main bearing member 11 facing the top end surface of the turning boss portion. The seal member 5 partitions the top end surface of the turning boss portion into a central part and a peripheral part. High-pressure gas or lubricating oil maintained at a high pressure is supplied to the central part of the turning boss portion. A lap of the turning scroll 13 is constructed on the inner side than the outer diameter of the turning boss portion. Consequently, since deformation of an end plate of the turning scroll 13 can be reduced while decreasing pressing force (thrust load) of the turning scroll 13 against a fixed scroll 12, a lap top end and a lap bottom surface can be prevented from strongly making sliding contact with each other. Therefore, it is possible to provide the scroll fluid machine having improved efficiency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate are meshed to form an expansion chamber therebetween, and the orbiting scroll is revolved along a circular orbit under the restriction of rotation by the rotation restriction mechanism. The present invention relates to a scroll fluid machine that performs suction and discharge when an expansion chamber moves while changing its volume.

  Conventionally, as this kind of scroll fluid machine (compressor), as shown in FIG. 5, the back pressure chamber M on the side opposite to the lap of the orbiting scroll (second scroll 3) and the upper peripheral portion on the crankshaft (drive shaft 5) side The sealing member (seal ring 7) for sealing the high pressure hydraulic chamber H of the rotating boss portion (boss cylinder 31) having the orbiting scroll bearing portion and the diametrically central portion of the frame (frame 4) facing the tip surface (See, for example, Patent Document 1).

According to this configuration, when the seal member is disposed on the end plate surface on the side opposite to the wrapping of the orbiting scroll, the outer diameter dimension of the orbiting boss must be made larger, so the high pressure region must be relatively large. However, there is a problem that the thrust load becomes excessive and the rotational load increases, but it is possible to avoid an excessive thrust load by disposing a seal member on the tip surface of the turning boss portion.
Japanese Patent Laid-Open No. 3-92502

  However, a thrust load is generated due to the difference between the force generated from the pressure of the compression chamber existing on the lap surface of the orbiting scroll and the force generated from the high pressure gas acting on the central portion of the seal member or the lubricant kept at a high pressure. If it is strongly pressed against the fixed scroll only at the center of the orbiting scroll, the end plate of the orbiting scroll is deformed and the wrap tip of the orbiting scroll and the bottom surface of the fixed scroll, or the bottom of the orbiting scroll and the wrap tip of the fixed scroll are strong. It had the problem of sliding and causing abnormal wear.

  In particular, when the scroll fluid machine is used as an expander and the refrigerant as the working fluid is carbon dioxide, the pressure rapidly decreases at the initial stage of the expansion process as shown in FIG. In this case, the force generated from the pressure of the expansion chamber existing on the wrap surface of the orbiting scroll is larger than the force generated from the pressure of the high pressure gas acting on the central portion of the seal member or the lubricating oil kept at a high pressure. By further increasing the size, the end plate of the orbiting scroll is further distorted. As a result, the center of the orbiting scroll is strongly pressed against the fixed scroll, and the wrap tip of the orbiting scroll and the bottom surface of the fixed scroll, or the lap bottom of the orbiting scroll and the wrap tip of the fixed scroll slide strongly. Had the problem of causing abnormal wear.

  The present invention solves the above-described conventional problems, and provides a highly efficient scroll fluid machine by preventing strong sliding between the lap tip and the lap bottom surface when the scroll fluid machine is used as an expander. Objective.

In order to solve the above-described conventional problems, the scroll fluid machine of the present invention includes a tip end surface of a turning boss portion having a bearing portion on the side opposite to the orbiting of the orbiting scroll, and an end surface of a central portion of the main bearing member facing the tip end surface. A seal member that partitions the central portion and the outer peripheral portion is arranged between the boss portion, high pressure gas or lubricating oil kept at a high pressure is supplied to the central portion of the swivel boss portion, and the swivel portion is turned inward from the outer diameter of the swivel boss portion. This is a scroll wrap. As a result, it is possible to reduce the deformation of the end plate of the orbiting scroll while reducing the pressing force (thrust load) of the orbiting scroll to the fixed scroll. A simple scroll fluid machine can be provided.

  The scroll fluid machine of the present invention can achieve high reliability and high efficiency, particularly when a carbon dioxide refrigerant, which is a high pressure / low compression ratio refrigerant, is used.

  1st invention partitions a center part and an outer peripheral part between the front end surface of the turning boss | hub part which has the bearing part of the anti-wrap side of a turning scroll, and the end surface of the main bearing member center part which opposes this. A sealing member is arranged, high-pressure gas or lubricating oil kept at a high pressure is supplied to the central portion of the orbiting boss, and the wrap of the orbiting scroll is configured inside the outer diameter of the orbiting boss. As a result, since the expansion chamber formed on the wrap side of the orbiting scroll exists only in the end plate boss area with high end plate rigidity, distortion of the orbiting scroll can be minimized. Thus, a highly efficient scroll fluid machine can be provided.

  In the second invention, in particular, the spiral wrap of the first invention is formed by an involute curve, and the center of the base circle of the involute curve is shifted from the center of the turning boss. As a result, even if the orbiting boss part is the same size, the number of turns of the swirl wrap of the orbiting scroll can be increased compared with the case where the center of the foundation circle of the involute curve coincides with the center of the orbiting boss part. A machine can be provided. In addition, when the number of turns is fixed, the wrap thickness can be increased, and a scroll fluid machine having higher reliability can be provided.

  In the third invention, in particular, the inner diameter of the orbiting boss portion of the first or second invention is such that the tip of the eccentric shaft portion of the crankshaft is at least on the lap side than the end plate surface on the opposite side of the orbiting scroll. Is deeply formed. As a result, the rigidity of the end plate area where the orbiting scroll wrap is formed is sufficiently high in rigidity, so even if the inner diameter of the orbiting boss increases, the distortion of the end plate is less affected. Since the length of the arm of the couple to be used can be reduced, a scroll fluid machine that can be operated more stably can be provided.

  In the fourth invention, in particular, the orbiting scroll is formed of an aluminum-based metal material and the fixed scroll is formed of an iron-based metal material according to any one of the first to third inventions. The seizure load when pressing the iron-based metal material and the aluminum-based metal material is higher than the seizure load when pressing the iron-based materials, so that galling and abnormal wear can be suppressed. In addition, since the aluminum-based metal material has a lower density than the iron-based metal material, the centrifugal force during operation can be kept small, so that the load on the shaft can be reduced. As a result, it is possible to provide a scroll fluid machine that achieves higher efficiency by reducing the loss of the bearing portion. Also, for aluminum-based metal materials, there is a problem that the amount of distortion of the orbiting scroll is larger than that of the fixed scroll because the longitudinal elastic modulus is smaller than that of the iron-based metal material. Since the expansion chamber formed on the wrap side of the metal plate exists only in the end plate boss part region having high end plate rigidity, distortion of the orbiting scroll can be minimized. A highly efficient scroll fluid machine can be provided while maximizing the advantages of the fixed scroll of the material.

  In the fifth aspect of the invention, in particular, the refrigerant as the working fluid of any one of the first to fourth aspects is carbon dioxide. As a result, carbon dioxide has a greater power recovery effect by the expander than other working fluids, so if a scroll fluid machine that realizes high reliability and high efficiency is used, higher reliability and high efficiency characteristics can be obtained. A refrigeration cycle apparatus having the above can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of a scroll fluid machine according to Embodiment 1 of the present invention. In FIG. 1, a main bearing member 11 that pivotally supports a main shaft portion 4 a of a crankshaft 4 fixed by welding or shrink fitting in the sealed container 1, and a fixed scroll 12 bolted on the main bearing member 11. A scroll-type expansion mechanism is formed by sandwiching the orbiting scroll 13 that meshes with the fixed scroll 12 between them, so that the orbiting scroll 13 is prevented from rotating between the orbiting scroll 13 and the main bearing member 11 and moves in a circular orbit. A rotation restricting mechanism 14 is provided by an Oldham ring or the like that guides the motor.

  In the above configuration, the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4 b at the upper end of the crankshaft 4 to cause the orbiting scroll 13 to move in a circular orbit, thereby forming between the fixed scroll 12 and the orbiting scroll 13. A refrigerant gas is sucked from a suction pipe 16 communicating with the outside of the hermetic container 1 and a suction port 17 at the center of the fixed scroll 12 by using the expansion chamber 15 which is enlarged while moving from the center to the outer peripheral side. The refrigerant gas that has been expanded and reduced to a predetermined pressure or less is repeatedly discharged out of the sealed container 1 from the discharge port 18 on the outer peripheral side of the fixed scroll 12.

  The other end of the crankshaft 4 is supported by the auxiliary bearing member 21, and a positive displacement pump 25 is provided at the other end of the crankshaft 4. The lubricating oil 6 lubricates and cools the main bearing portion 11a and the eccentric bearing portion 11b through a lubricating oil reservoir 20 through a positive displacement pump 25 (not shown) provided in the center of the crankshaft 4 in the axial direction. After that, recirculation is performed through the lubricating oil return hole 26. A seal member 5 that partitions the central portion and the outer peripheral portion is disposed on the tip surface of the boss portion on the opposite side of the orbiting scroll 13.

  Further, the inside of the sealed container 1 communicates with a compressor (not shown) through the pressure equalizing tube 40, and the pressure in the sealed container 1 is kept at a high pressure. At the same time, the lubricating oil reservoir 20 in the sealed container 1 communicates with the lubricating oil reservoir (not shown) of the compressor, and the lubricating oil 6 is supplied into the compressor and the sealed container 1 without excess or deficiency. Yes. At this time, since the seal member 5 has a role of partitioning the pressure of the lubricating oil 6 reaching the eccentric bearing portion 11b and the pressure of the back pressure chamber 29, the central portion of the seal member 5 is kept at a high pressure. The back pressure chamber 29 is in pressure communication with the discharged refrigerant and is kept at a low pressure. The lubricating oil 6 leaking from the seal member 5 is discharged to the outside of the sealed container 1 together with the discharged refrigerant after lubricating the rotation restricting mechanism 14.

  FIG. 2 is a perspective view of the orbiting scroll constituting the scroll fluid machine according to Embodiment 1 of the present invention. As can be seen from FIG. 2, the spiral wrap of the orbiting scroll 13 is configured within the boss outer diameter range. As a result, since the expansion chamber 15 formed on the wrap side of the orbiting scroll 13 exists only in the end plate boss part region having a high end plate rigidity, distortion of the orbiting scroll 13 can be minimized. A highly efficient scroll fluid machine can be provided by preventing strong sliding of the bottom surface of the wrap.

FIG. 3 is a plan view of the orbiting scroll constituting the scroll fluid machine in the first embodiment of the present invention. In FIG. 3, the spiral wrap is formed by an involute curve, and the center of the base circle of the involute curve is shifted from the center of the swivel boss part. As a result, even if the orbiting boss part is the same size, the number of turns of the spiral wrap of the orbiting scroll 13 can be increased compared with the case where the center of the base circle of the involute curve is coincident with the center of the orbiting boss part. A highly efficient scroll fluid machine can be provided for large operating conditions. In addition, when the number of turns is fixed, the wrap thickness can be increased (not shown), and a scroll fluid machine with higher reliability can be provided.

  FIG. 4 is a side view of the orbiting scroll constituting the scroll fluid machine in the first embodiment of the present invention. In FIG. 4, the inner diameter of the orbiting boss portion is deeply formed so that the tip of the eccentric shaft portion 4 b of the crankshaft 4 is at least on the lap side than the end plate surface on the side opposite to the wrapping scroll 13. As a result, the region of the end plate where the wrap of the orbiting scroll 13 is formed is sufficiently high in rigidity, so that even if the depth of the inner diameter of the orbiting boss portion increases, the distortion of the end plate is less affected. Since the length of the arm of the couple to be overturned can be reduced, a scroll fluid machine that can be operated more stably can be provided.

  When the orbiting scroll 13 is formed of an aluminum-based metal material and the fixed scroll 12 is formed of an iron-based metal material, the seizure load when pressing the iron-based metal material and the aluminum-based metal material is the same between the iron-based materials. Since it becomes higher than the seizing load in the case of pressing, galling and abnormal wear can be suppressed. In addition, since the aluminum-based metal material has a lower density than the iron-based metal material, the centrifugal force during operation can be suppressed to a small value, so that the load on the crankshaft 4 can be reduced. As a result, it is possible to provide a scroll fluid machine that achieves higher efficiency by reducing the loss of the bearing portion. On the other hand, the aluminum-based metal material has a problem that the amount of distortion of the orbiting scroll 13 is larger than that of the fixed scroll 12 because the longitudinal elastic modulus is smaller than that of the iron-based metal material. For example, since the expansion chamber 15 formed on the lap side of the orbiting scroll 13 exists only in the end plate boss portion region having a high end plate rigidity, the distortion of the orbiting scroll 13 can be minimized. And abnormal wear can be prevented. As a result, it is possible to provide a highly efficient scroll fluid machine while maximizing the advantages of an aluminum-based metal orbiting scroll and an iron-based metal material fixed scroll.

  In addition, when the refrigerant as the working fluid is carbon dioxide, the scroll fluid machine that realizes high reliability and high efficiency because carbon dioxide has a larger power recovery effect by the expander than other working fluids. Can be used to provide a refrigeration cycle apparatus having higher reliability and higher efficiency.

  As described above, the scroll fluid machine according to the present invention is provided between the distal end surface of the orbiting boss portion having the bearing portion on the anti-wrap side of the orbiting scroll and the end surface of the central portion of the main bearing member opposed to the end surface. A seal member that partitions the central portion and the outer peripheral portion is disposed, high pressure gas or lubricating oil maintained at high pressure is supplied to the central portion of the orbiting boss portion, and the orbiting scroll wrap is provided inside the outer diameter of the orbiting boss portion. It is composed. As a result, it is possible to reduce the deformation of the end plate of the orbiting scroll while reducing the pressing force (thrust load) of the orbiting scroll to the fixed scroll. Therefore, the present invention can be applied not only to a working fluid as a refrigerant but also to a scroll fluid machine including a scroll expander using air and helium as a working fluid and a compressor.

Sectional drawing of the scroll fluid machine in Embodiment 1 of this invention The perspective view of the turning scroll in Embodiment 1 of this invention Plan view of orbiting scroll in Embodiment 1 of the present invention Sectional drawing of the turning scroll in Embodiment 1 of this invention An enlarged cross-sectional view of a main part near a seal member in a conventional scroll compressor Schematic diagram showing the balance of force when carbon dioxide is used as a refrigerant as an expander in a conventional scroll compressor

Explanation of symbols

2 Compression Mechanism 5 Seal Member 6 Lubricating Oil 12 Fixed Scroll 13 Orbiting Scroll 14 Rotation Restriction Mechanism 15 Expansion Chamber 17 Suction Port 29 Back Pressure Chamber

Claims (5)

The expansion mechanism portion and the electric mechanism portion are connected and stored in a sealed container via a crankshaft, and the expansion mechanism portion engages the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate, and between them. An expansion chamber is formed, and the expansion chamber moves while changing its volume when the orbiting scroll is rotated under the rotation restriction by the rotation restriction mechanism while engaging the eccentric shaft portion connected to the crankshaft. A scroll expansion mechanism portion that sucks and discharges the working fluid, and includes a tip surface of the orbiting boss portion having a bearing portion on the side opposite to the wrapping of the orbiting scroll, and a central portion of the main bearing member facing the end surface. A sealing member for partitioning a central portion and an outer peripheral portion between the end surface of the rotating boss portion, supplying high-pressure gas or lubricating oil maintained at a high pressure to the central portion of the rotating boss portion, and the rotating boss Inward than the outer diameter, a scroll fluid machine, characterized in that to constitute a lap of the orbiting scroll. 2. The scroll fluid machine according to claim 1, wherein the spiral wrap is formed by an involute curve, and a center of a base circle of the involute curve is arranged so as to be shifted from a center of the orbiting boss part. The inner diameter depth of the orbiting boss portion is formed so that the tip of the eccentric shaft portion of the crankshaft is at least inside the end plate surface on the side opposite to the wrapping of the orbiting scroll. The scroll fluid machine according to 2. The scroll fluid machine according to any one of claims 1 to 3, wherein the orbiting scroll is formed of an aluminum-based metal material and the fixed scroll is formed of an iron-based metal material. The scroll fluid machine according to claim 1, wherein the refrigerant as the working fluid is carbon dioxide.