JP2019044731A - Scroll fluid machine - Google Patents

Abstract

To prevent creep of a rolling bearing mounted on a crank shaft even in a case where a swing scroll is made of aluminum alloy in a scroll fluid machine.SOLUTION: A scroll fluid machine includes a swing scroll 2 provided with a swing lap 6, a housing material 4 for housing the swing scroll 2, a fixed scroll 5 provided with a fixed lap 50 and fixed to the housing material 4, and a crank shaft 3 for swingably holding the swing scroll 2. On the crank shaft 3, the swing scroll 2 is held on an eccentric shaft portion 8 through the rolling bearing 29. The swing scroll 2 is made of aluminum alloy, and a bearing mounting hole 33 is formed at an outer side of the swing lap 6. In the rolling bearing 29, a raceway ring and a rolling element are made of steel, and a resin belt-shaped spacer 57 is attached to an outer peripheral face of an outer ring, and the rolling bearing is press-fitted into the bearing mounting hole 33.SELECTED DRAWING: Figure 2

Description

  The present invention relates to scroll fluid machines used as air compressors or steam expanders.

  Conventionally, as disclosed in the following patent documents, a scroll fluid machine provided with three crankshafts for preventing rotation is known. In this scroll fluid machine, the orbiting scroll is provided with orbiting wraps on both sides of the base plate portion, and is held by eccentric shaft portions of three crankshafts via steel rolling bearings. The outer ring of the rolling bearing is fitted, for example, by tight fitting to a bearing mounting hole provided in the orbiting scroll. That is, when the outer diameter of the outer ring is d and the inner diameter of the bearing mounting hole is D, the rolling bearing in the relationship of d> D is press-fit into the bearing mounting hole of the orbiting scroll. Further, in the axial direction, the outer ring of the rolling bearing is held in a pressed state by the retaining ring (pressing plate) in a state where the end face is in contact with the stepped portion of the bearing mounting hole.

  In recent years, for the purpose of reducing the weight of the scroll fluid machine, there has been an attempt to form the orbiting scroll, the fixed scroll, the housing and the like from an aluminum alloy which is a light metal. However, for example, when the orbiting scroll of the air compressor is formed of aluminum alloy, the difference in linear expansion coefficient between the orbiting scroll made of aluminum alloy and the outer ring of steel rolling bearing (linear expansion coefficient of aluminum alloy> steel Depending on the coefficient of linear expansion, temperature rise during compression operation may reduce the fitting interference ((d−D) / 2) between the bearing mounting hole and the outer ring. Similarly, for example, when the orbiting scroll of the steam expander is formed of an aluminum alloy, the temperature increase at the time of steam introduction reduces the interference ((d−D) / 2) of the fit between the bearing mounting hole and the outer ring. there's a possibility that. Then, when the interference decreases, there is a possibility that the outer ring creeps even though the outer ring is held in the axial direction.

  The term "creep" refers to a phenomenon in which the bearing is finely moved in the direction opposite to the direction of rotation / rotation due to insufficient fit of the fit and poor machining accuracy of the fit surface. In particular, since the centrifugal force acts on the rolling bearings of the crankshaft during the turning movement of the turning scroll, creep is likely to occur if the fitting interference is insufficient. And, when the creep of the bearing continues, the fitting surface of the outer ring becomes a mirror surface, and if this is accompanied by galling, there is a possibility that seizing or welding may occur.

JP 2003-120552 A JP 2006-97531 A

  The problem to be solved by the present invention is to provide a scroll fluid machine capable of preventing creep of a rolling bearing attached to a crankshaft even when the orbiting scroll is formed of an aluminum alloy.

  The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is a scroll fluid machine used as an air compressor or a steam expander, comprising: pivot wraps on both sides of a substrate portion A rotating scroll provided with the housing, a housing member for accommodating the rotating scroll, and a pair of fixed scrolls fixed to the housing member so as to sandwich the rotating scroll. Crankshafts arranged at equal intervals at three or more locations in the circumferential direction of the orbiting scroll, wherein the eccentric shafts of the crankshafts are provided eccentrically between main shaft units arranged on the same axis; both sides In the main shaft portion, the rotary scroll is held by the housing member rotatably via the rolling bearing at the eccentric shaft portion. The orbiting scroll is pivotally held with respect to a fixed scroll, the orbiting scroll is formed of an aluminum alloy, and a bearing mounting hole is provided on the outside of the orbiting wrap, and the rolling bearing is a bearing ring and a rolling element Is an expansion correction bearing in which a belt-shaped spacer made of resin is attached to the outer peripheral surface of the outer ring while being made of steel, and the expansion correction bearing is press-fitted and accommodated in the bearing mounting hole. It is a scroll fluid machine.

  According to the first aspect of the present invention, the orbiting scroll made of aluminum alloy is held by the eccentric shaft portion of the crankshaft via the steel rolling bearing. By forming the orbiting scroll from aluminum alloy, the weight of the scroll fluid machine can be reduced. Further, even when the orbiting scroll is formed of an aluminum alloy, as described below, the creep of the rolling bearing can be prevented by stabilizing the interference of the strip-like spacer provided on the outer peripheral surface of the outer ring of the rolling bearing. .

  That is, first, the rolling bearing is an expansion correction bearing in which a resin-made band-like spacer is attached to the outer peripheral surface of the outer ring, and is press-fitted into the bearing mounting hole of the orbiting scroll. That is, assuming that the outer diameter of the strip spacer is d1 and the inner diameter of the bearing mounting hole is D, the strip spacer in the relationship of d1> D is tightly fitted to the bearing mounting hole. Since the linear expansion coefficient of the aluminum alloy forming the orbiting scroll is larger than the linear expansion coefficient of the steel forming the rolling bearing, if the temperature rises with the use of the scroll fluid machine, the outer diameter of the outer ring and the bearing mounting hole The gap with the inner diameter is large. However, since the linear expansion coefficient of the strip spacer (resin) is larger than that of the orbiting scroll (aluminum alloy), the thermal expansion of the orbiting scroll can be reliably followed when the temperature rises. It is possible to stabilize the white ((d1-D) / 2). Therefore, even when the orbiting scroll is formed of an aluminum alloy, creep of the rolling bearing attached to the crankshaft can be prevented.

  According to a second aspect of the present invention, the orbiting scroll comprises Si: 8.0 to 11.0% by mass, Mg: 0.3 to 0.6% by mass, and Mn: 0.3 to 0.6% by mass. The aluminum alloy is formed of an Al-Si-Mg-Mn-based aluminum alloy that contains 0.5% by mass or less of Cu and 0.7% by mass or less of Fe. It is a scroll fluid machine according to claim 1.

  According to the second aspect of the present invention, the corrosion resistance can be kept good even when used not only as an air compressor but also as a steam expander.

  The invention according to claim 3 is a kind of the belt-like spacer selected from polyamide resin, polyacetal resin, polybutylene terephthalate resin, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer The scroll fluid machine according to claim 1 or 2, which is made of the above resin material and has a water absorption rate of 1% or less.

  According to the third aspect of the present invention, since the strip-shaped spacer provided on the outer ring of the rolling bearing and press-fit into the bearing mounting hole of the orbiting scroll has a hardness not to be distorted by the centrifugal force due to the orbiting of the orbiting scroll. It is possible to stabilize the interference of the strip spacer including the start and stop. Further, since the strip spacer is formed of a material having a low water absorption rate, it is possible to suppress a change in fit due to swelling and to prevent cracking and deformation. Therefore, the operation can be stabilized even when used in a water addition type air compressor or a steam expander.

  The invention according to claim 4 is that the rolling bearing is a deep groove ball bearing; and the bearing ring and the rolling element are high carbon chromium steel, hardened case steel, stainless steel, high speed steel, or induction hardened. It is formed by steel, It is a scroll fluid machine of any one of the Claims 1-3 characterized by the above-mentioned.

  According to the fourth aspect of the present invention, a rolling bearing with high accuracy and long life can be obtained.

  Furthermore, the invention according to claim 5 is the scroll fluid machine according to any one of claims 1 to 4, wherein a plurality of the expansion correction bearings are provided in the eccentric shaft portion. .

  According to the fifth aspect of the present invention, the operation of the orbiting scroll can be further stabilized by reliably holding the orbiting scroll on the eccentric shaft portion of the crankshaft by using a plurality of expansion correction bearings.

  According to the scroll fluid machine of the present invention, even when the orbiting scroll is formed of an aluminum alloy, the creep of the rolling bearing attached to the crankshaft can be prevented.

FIG. 1 is a schematic bottom view of a scroll fluid machine according to an embodiment of the present invention. It is II-II sectional drawing in FIG. It is a disassembled perspective view of the turning scroll of the scroll fluid machine of FIG. It is an enlarged view of the left end part of FIG. It is the schematic at the time of attachment of the turning bearing to the bearing attachment hole of the turning scroll of FIG.

  Hereinafter, specific embodiments of the present invention will be described in detail based on the drawings.

  1 to 4 are schematic views showing a scroll fluid machine 1 according to an embodiment of the present invention, wherein FIG. 1 is a bottom view, FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 4 is an enlarged view of the left end portion of FIG. 2. In the following, for convenience of explanation, the direction may be described as upper and lower and right and left in FIG. 2 (strictly, it is a left half or right half thereof because it is a II-II cross sectional view). It does not mean to limit the attitude of Therefore, when the scroll fluid machine 1 is used, the crankshaft 3 may be disposed, for example, in the left-right direction in addition to being disposed in the up-down direction.

  The scroll fluid machine 1 according to the present embodiment includes a housing member 4, a orbiting scroll 2 rotatably held by the housing member 4 via a plurality of crankshafts 3, and a housing member 4 so as to sandwich the orbiting scroll 2. And a pair of fixed scrolls 5 which are detachably fixed to each other. The crankshafts 3 are preferably provided at three circumferentially-spaced intervals on the outer peripheral portion of the orbiting scroll 2.

  In the present embodiment, the housing member 4 is formed in a substantially rectangular box shape, and an accommodation hole 7 for pivotably accommodating the orbiting wrap 6 of the orbiting scroll 2 is vertically formed in the central portion in plan view There is. In the housing member 4, the crankshaft 3 is provided parallel to the axis of the accommodation hole 7 at a plurality of circumferential positions surrounding the accommodation hole 7, and the accommodation space 9 of the eccentric shaft portion 8 of the crankshaft 3 is accommodated in the accommodation hole 7. It communicates through the opening 10.

  Specifically, the housing member 4 of the present embodiment includes a substantially rectangular flat plate-like upper plate 11 and a lower plate 12, which are formed in mutually corresponding sizes. The upper plate 11 and the lower plate 12 are vertically separated and disposed to face each other in parallel, and the outer edges are connected by an appropriate side plate 13. At this time, the upper plate 11 and the lower plate 12 connect the lower surface of the upper plate 11 and the upper surface of the lower plate 12 with the side plate 13 as in the front and rear end sides of FIG. 1 (that is, the right side in FIG. 2). The end face of the upper plate 11 and the end face of the lower plate 12 may be connected by the side plate 13 as in the left and right end sides of FIG. 1 (that is, the left side of FIG. 2). Further, each side plate 13 may be provided in the entire area of the end sides of the upper plate 11 and the lower plate 12 like the right side plate 13 of FIG. 1 or like the left side plate 13 of FIG. It may be provided on a part of the edge of the lower plate 12 and the lower plate 12. Each of the plates 11 to 13 is detachably assembled using a bolt 14 so that, for example, the upper plate 11 can be removed from each side plate 13. In addition, not only a literal bolt but various kinds of screws may be used as the bolt 14, and the same applies to other bolts described later.

  An opening 7A is formed through the upper plate 11 and the lower plate 12 as the opening of the accommodation hole 7 (in other words, the opening of the hollow portion in the housing member 4) at corresponding locations. The upper and lower opening holes 7A are formed of round holes of the same size. In the case of the illustrated example, the peripheral wall of the upper opening hole 7A protrudes below the lower surface of the upper plate 11, and the peripheral wall of the lower opening hole 7A protrudes above the upper surface of the lower plate 12.

  An annular flange 15 is formed at the bottom of each opening 7A. Specifically, the lower end portion of the peripheral wall of the upper opening hole 7A extends radially inward to have a flange 15, while the upper end portion of the peripheral wall of the lower opening hole 7A extends radially inward The flange 15 is provided. In the housing member 4, an annular hollow portion is formed radially outward of the respective flanges 15, and the hollow portion becomes an accommodation space 9 of the eccentric shaft portion 8 of the crankshaft 3. And this accommodation space 9 is continuously opened along the circumferential direction via the opening 10 between the pair of flanges 15 to the accommodation hole 7 (a hollow portion virtually connecting the upper and lower opening holes 7A). It is open.

  The orbiting scroll 2 is provided with an orbiting scroll main body 17 in which a spiral orbiting wrap 6 is provided on both sides of a substrate portion 16 as shown in FIGS. 2 and 3. It is detachably attached to the central receiving hole 19 from one side (here, the upper surface).

  The orbiting scroll main body 17 is configured to have one or a plurality of plate-like orbiting wraps 6 provided on upper and lower surfaces of the disk-like substrate portion 16 so as to extend perpendicularly to these surfaces. Specifically, the turning wrap 6 is provided on the upper surface of the substrate portion 16 upward, and the turning wrap 6 is provided on the lower surface of the substrate portion 16 downward. Under the present circumstances, each turning wrap 6 is curved and formed in the spiral shape of an involute curve toward the outer peripheral part from the center part of the board | substrate part 16. As shown in FIG. In the present embodiment, as is apparent from FIG. 2, the upper and lower pivot wraps 6 are formed in shapes, sizes and arrangements corresponding to each other.

  As shown in FIG. 2, the end of the fixed scroll 5 is provided at each of the turning wraps 6 at the leading end extending from the base portion 16 (upper end of the upper turning wrap 6, lower end of the lower turning wrap 6). A tip seal 21 for filling the gap with the plate 20 is detachably provided along the spiral. In FIG. 3, the tip seal 21 is omitted.

  As shown in FIG. 3, radially outward extending pieces 22 are provided at a plurality of circumferential positions on the outer peripheral portion of the substrate portion 16. In this embodiment, a plurality of sets are provided circumferentially at equal intervals, with a pair of extension pieces 22 arranged adjacent to each other as one set. Specifically, three sets of extension pieces 22 are integrally formed on the outer peripheral portion of the substrate portion 16 at an interval of 120 degrees.

  Each of the extension pieces 22 is formed in a plate shape whose upper surface is continuous with the substrate portion 16 and is formed slightly thinner than the substrate portion 16 as shown on the right side of FIG. As shown in FIG. 3, two bolt insertion holes 23 are formed vertically through the plate surface of each of the extension pieces 22 so as to be separated in the circumferential direction of the substrate portion 16. Further, pin holes 25 into which lock pins 24 described later are fitted are also formed in the two extending pieces 22 so as to face the substrate portion 16 in the substantially radial direction.

  The orbiting scroll base 18 may have, for example, a substantially circular shape in a plan view, but is formed in a substantially triangular shape as shown in FIG. 3 in the present embodiment. In any case, in the central portion of the orbiting scroll base 18, a receiving hole 19 for receiving the substrate portion 16 of the orbiting scroll main body 17 is formed to penetrate.

  As described later, when heat transfer from the orbiting scroll main body 17 to the orbiting scroll base 18 is prevented, the inner diameter of the receiving hole 19 is larger than the outer diameter of the substrate portion 16 by the set dimension. In that case, the substrate portion 16 of the orbiting scroll main body 17 is inserted into the receiving hole 19 of the orbiting scroll base 18 with a gap between the inner peripheral surface of the receiving hole 19 and the outer peripheral surface of the substrate portion 16.

  In the orbiting scroll base 18, a recess 26 for receiving the extending piece 22 of the orbiting scroll main body 17 is formed around the receiving hole 19 so as to cut out the inner peripheral wall of the receiving hole 19 and formed upward. There is. The bottom surface of the recess 26 is disposed at the axial center of the receiving hole 19. The base portion 16 of the orbiting scroll main body 17 can be inserted into the receiving hole 19 of the orbiting scroll base 18 while the extension piece 22 of the orbiting scroll main body 17 is fitted into the recess 26 of the orbiting scroll base 18.

  Screw holes 27 are formed on the bottom surface of each recess 26 of the orbiting scroll base 18 in correspondence with the bolt insertion holes 23 formed in the extending piece 22 of the orbiting scroll main body 17. Further, lock pins 24 are provided on the bottom surface of the recess 26 so as to protrude upward at two locations facing in the substantially radial direction of the receiving hole 19. Therefore, by circumferentially positioning the orbiting scroll main body 17 with respect to the orbiting scroll base 18 by inserting the pin holes 25 of the extension piece 22 of the orbiting scroll main body 17 into the lock pins 24 of the recess 26 of the orbiting scroll base 18. Can. The orbiting scroll main body 17 can be detachably fixed to the orbiting scroll base 18 by screwing the bolt 28 into the screw hole 27 of the recess 26 through the bolt insertion hole 23 of the extension piece 22. However, the lock pin 24 and the pin hole 25 can be omitted if necessary.

  Although details will be described later, at three corners of the orbiting scroll base 18, orbiting bearings 29 are provided to hold the orbiting scroll base 18 on the eccentric shaft 8 of the crankshaft 3 (FIGS. 2 and 5). ). It is preferable to prevent heat transfer from the orbiting scroll main body 17 to the orbiting scroll base 18 in order to protect the orbiting bearing 29 (more specifically, to prevent grease breakage). For that purpose, as shown in FIG. 3, the orbiting scroll main body 17 and the orbiting scroll base 18 are preferably overlapped via the first intermediate member 30 so as not to be in direct contact with each other.

  In the present embodiment, a washer-like intermediate material 30 is interposed between the lower surface of the extension piece 22 and the bottom surface of the recess 26. That is, the bolt 28 for fixing the orbiting scroll main body 17 to the orbiting scroll base 18 passes through the bolt insertion hole 23 of the extension piece 22 of the orbiting scroll main body 17 and the hole of the intermediate member 30, and then the orbiting scroll base Screwed into 18 screw holes 27.

  In the illustrated example, the orbiting scroll main body 17 is fixed to the orbiting scroll base 18 by 12 bolts 28. Among them, the intermediate material 30 is the heat insulating material 30A at half of the locations and the other half of the locations. Then, the intermediate material 30 is made into the spacer 30B. Specifically, a receiving hole 19 is formed between a pair of recesses 26 arranged corresponding to each corner of the substantially triangular turning scroll base 18 and a pair of extension pieces 22 attached thereto. Intermediate material 30 is provided along the circumferential direction, for example, in the order of spacer 30B, heat insulator 30A, heat insulator 30A and spacer 30B.

  In the present embodiment, both the heat insulating material 30A and the spacer 30B have substantially the same shape and size as each other, but may differ depending on the case. By using the spacer 30B according to the thickness and hardness of the heat insulating material 30A, material selection of the heat insulating material 30A is facilitated. Further, as described later, if the spacer 30B is formed of a metal material, thickness accuracy can be easily obtained, and deformation due to a tightening load by the bolt 28 can be suppressed. Since the installation height of the orbiting scroll main body 17 with respect to the orbiting scroll base 18 can be maintained at a predetermined level by sandwiching not only the heat insulating material 30A but also the metal spacer 30B between the recess 26 and the extension piece 22, the orbiting scroll 2 and The arrangement in the vertical direction with the fixed scroll 5 is determined in a predetermined manner, and the variation in the clearance at the tip seal 21 or 51 after assembly can be suppressed, and fluid leakage can be prevented.

  In any case, the intermediate material 30 is formed of a material having a thermal conductivity lower than that of the orbiting scroll base 18. From this point of view, even when the intermediate material 30 is the spacer 30B described above, the spacer 30B also functions as a kind of heat insulating material. In this embodiment, the orbiting scroll main body 17 and the orbiting scroll base 18 are formed of a lightweight aluminum alloy, but the intermediate member 30 is, for example, a heat insulator 30A made of ceramic or synthetic resin or a spacer 30B made of stainless steel. Ru. Then, as described above, in the receiving hole 19 of the orbiting scroll base 18, the base portion 16 of the orbiting scroll main body 17 opens a gap between the inner peripheral surface of the receiving hole 19 and the outer peripheral surface of the base portion 16. Be fitted. Further, the recess 26 of the orbiting scroll base 18 and the extending piece 22 of the orbiting scroll main body 17 not only do not directly contact the bottom surface of the recess 26 and the lower surface of the extending piece 22 via the intermediate member 30, but also extend By forming the recess 26 one size larger than the piece 22, the side surface of the recess 26 and the outer edge of the extending piece 22 are not in direct contact with each other. Furthermore, in addition to the bolt 28 used to fix the orbiting scroll main body 17 to the orbiting scroll base 18, preferably also the lock pin 24 is a material having a lower thermal conductivity than the orbiting scroll base 18 (aluminum alloy) (stainless steel here) It is formed of Thus, the heat transfer from the orbiting scroll main body 17 to the orbiting scroll base 18 can be prevented, and the orbiting bearing 29 can be protected.

  When the base portion 16 of the orbiting scroll main body 17 is inserted into the receiving hole 19 of the orbiting scroll base 18 with a gap, the positioning of the orbiting scroll main body 17 with respect to the orbiting scroll base 18 in the radial direction is performed as follows. Is preferred. That is, at the circumferential side wall of the receiving hole 19, preferably at equal intervals in the circumferential direction, the support member (31) is provided by projecting the tip portion into the receiving hole 19 at three or more places in the circumferential direction. In the present embodiment, a screw hole 32 is formed in the central portion of each of the three end sides of the substantially triangular orbiting scroll base 18 in the radial direction, and a screw 31 as a supporting material is formed in the screw hole 32. Screw in (eg hex socket set screw). The distal end of the thumbscrew 31 projects inward from the circumferential wall of the receiving hole 19. The tip end portion of the thumbscrew 31 abuts on the outer peripheral portion of the base portion 16 of the orbiting scroll main body 17 to hold (chuck) the base portion 16, thereby positioning the base portion 16 in the radial direction with respect to the receiving hole 19. be able to. The position of the substrate portion 16 with respect to the receiving hole 19 can be adjusted by advancing and retracting the screw 31 with respect to the screw hole 32. Further, if desired, an adhesive may be used to fix the anchor screw 31 to the orbiting scroll base 18. After the position of the base plate portion 16 with respect to the receiving hole 19 is determined by the imo screw 31, the position of the inner screw 31 is fixed, and the orbiting scroll main body 17 is axially oriented with respect to the orbiting scroll base 18 (vertical direction to the plate surface of the board portion 16) It can be attached and detached. In order to prevent heat transfer from the orbiting scroll main body 17 to the orbiting scroll base 18, the immo screw 31 is also preferably formed of a material having a thermal conductivity lower than that of the orbiting scroll base 18, and is formed of stainless steel in this embodiment. It is done. In addition, when employ | adopting such a structure, the lock pin 24 and the pin hole 25 which were mentioned above are comprised so that a clearance fit may fit.

  In the outer peripheral portion of the orbiting scroll base 18, bearing mounting holes 33 to the crankshaft 3 are formed at three places at equal intervals in the circumferential direction. In the present embodiment, the orbiting scroll base 18 is substantially triangular in plan view, but the bearing mounting holes 33 are formed vertically through the three corner portions. Each bearing mounting hole 33 is a stepped hole, and a large diameter hole 33a is disposed at the top and a small diameter hole 33b is disposed at the bottom.

  In the orbiting scroll 2, in a state where the orbiting wrap 6 is disposed in the accommodation hole 7 of the housing material 4, the substrate portion 16 and the orbiting scroll base 18 are disposed perpendicular to the axis of the accommodation hole 7. At this time, the orbiting scroll base 18 extends outward from the accommodation hole 7 through the opening 10 between the flanges 15 of the housing member 4. Thus, each bearing mounting hole 33 of the orbiting scroll base 18 is disposed radially outward of the flange 15 of the housing member 4. The orbiting scroll 2 is held by the crankshaft 3 via the orbiting bearing 29 attached to the bearing attachment hole 33. The holding structure will be described later. In addition, as shown in FIG. 1, the crankshaft 3 is provided in three places of the circumferential direction equal intervals of the housing material 4, and it is mutually the same structure in a present Example. Moreover, as shown in FIG. 2, each crankshaft 3 is arrange | positioned along the up-down direction for the axis line. Under the present circumstances, each crankshaft 3 is provided so that the hollow part of the housing material 4 may be penetrated up and down.

  As shown in FIG. 2 (especially on the left side) and FIG. 4, each crankshaft 3 is provided with an eccentric shaft portion 8 between the main shaft portions 34 and 35 disposed on the same axis eccentrically. In the present embodiment, the lower main shaft portion 35 is gradually reduced in diameter as it goes downward, and is divided into a large diameter portion 35a, an intermediate diameter portion 35b and a small diameter portion 35c. Further, at the lower end portion of the eccentric shaft portion 8, an enlarged diameter portion 8a is formed concentrically.

  Each crankshaft 3 is rotatably held by the upper plate 11 and the lower plate 12 of the housing member 4 at the main shaft portions 34 and 35 on both sides of the eccentric shaft portion 8. In the present embodiment, the upper main shaft portion 34 is rotatably held by the upper plate 11 of the housing member 4 via the upper bearing 36, and the middle diameter portion 35b of the lower main shaft portion 35 is via the lower bearing 37. It is rotatably held by the lower plate 12 of the housing member 4.

  In each crankshaft 3, a first step portion 3a is provided at an axial midway portion of one main shaft portion (the lower main shaft portion in FIG. 2) of the main shaft portions 34, 35 on both sides sandwiching the eccentric shaft portion 8. Provided. Specifically, the lower main shaft portion 35 is formed in a stepped rod shape as described above, and the stepped portion (the lower surface of the large diameter portion 35a) of the large diameter portion 35a and the medium diameter portion 35b is the first It is referred to as a step 3a. The upper end surface of the inner ring of the lower bearing 37 is in contact with the first step 3a.

  In each crankshaft 3, a second step 3 b is provided at one axial end (lower end in FIG. 2) of the eccentric shaft 8. Specifically, the eccentric shaft portion 8 is provided with the enlarged diameter portion 8a at the lower end portion as described above, and the stepped portion (upper surface of the enlarged diameter portion 8a) with the enlarged diameter portion 8a is the first The two-stage portion 3b is used. The lower end surface of the inner ring of the turning bearing 29 is in contact with the second step 3b. The number of the pivot bearings 29 provided on the eccentric shaft portion 8 may be one or more, and in the case of a plurality, the lower end surface of the inner ring of the pivot bearing 29 disposed at the lowermost end is in contact with the second step 3b. In the illustrated example, the two pivot bearings 29 are installed on the eccentric shaft 8 so as to be stacked one on top of the other.

  Shaft mounting holes 38 and 39 are formed on the upper plate 11 and the lower plate 12 of the housing member 4 at three locations in the circumferential direction corresponding to the installation position of the crankshaft 3. The shaft mounting hole 38 of the upper plate 11 of the housing member 4 is formed in a stepped hole, and a small diameter hole 38a is formed below and a large diameter hole 38b is formed above. The shaft mounting hole 39 of the lower plate 12 of the housing member 4 is also formed in a stepped hole, and a small diameter hole 39a is formed above and a large diameter hole 39b is formed below.

  The upper bearing 36 and the lower bearing 37 are both configured by rolling bearings in this embodiment. As is well known, the rolling bearing is configured by being arranged in the circumferential direction between a substantially cylindrical inner ring and an outer ring arranged concentrically and holding a large number of rolling elements. As a result, in the rolling bearing, the inner ring and the outer ring are made rotatable via the rolling elements. The inner ring and the outer ring are collectively referred to as a bearing ring. In addition, although the rolling elements here are balls (spherical bodies), they may be rollers (cylindrical bodies) as the case may be.

  Fixing of the lower bearing 37 to the lower plate 12 of the housing member 4 is performed as follows. That is, the lower bearing 37 is fixed to the large diameter hole 39b until the upper end face of the outer ring abuts on the stepped portion (upper surface of the large diameter hole 39b) of the small diameter hole 39a and the large diameter hole 39b of the shaft mounting hole 39 of the lower plate 12. Press-fit the outer ring. Then, the annular retaining ring 40 is superimposed on the lower surface of the lower plate 12 and fixed by the bolt 41. As a result, the lower bearing 37 is fixed by pinching the outer ring between the stepped portion of the shaft mounting hole 39 and the retaining ring 40.

  The middle diameter portion 35 b of the lower main shaft portion 35 is press-fitted to the inner ring of the lower bearing 37. That is, the middle diameter portion 35b of the main shaft portion 35 is press-fit into the inner ring of the lower bearing 37 until the upper end surface of the inner ring of the lower bearing 37 abuts on the first step 3a. And since the lower end part of middle diameter part 35b is made into the screw part, the 1st retaining nut 42 is screwed in the screw part. Thus, the lower bearing 37 has the inner ring sandwiched and fixed between the first step 3 a and the retaining nut 42.

  Fixing of the upper bearing 36 to the upper plate 11 of the housing member 4 is performed as follows. That is, in the upper bearing 36, the outer ring is held by the bearing case 43, and the bearing case 43 is fitted into the large diameter hole 38b until the lower surface of the flange of the bearing case 43 abuts on the upper surface of the upper plate 11. Then, the flange of the bearing case 43 is fixed to the upper surface of the upper plate 11 with a bolt 44. On the other hand, the upper main shaft portion 34 is press-fitted to the inner ring of the upper bearing 36.

  The three crankshafts 3 are synchronously rotated by the rotation synchronization mechanism 45 with the positions of the eccentric shaft portions 8 aligned (that is, the phases aligned). The rotation synchronization mechanism 45 may use a gear, but in the present embodiment, a timing belt 46 is used. Specifically, a toothed pulley 47 is fixed to the lower main shaft portion 35 (small diameter portion 35c) of each crankshaft 3, and a timing belt 46 is wound around the toothed pulley 47. At this time, as shown in FIG. 1, the timing belt 46 is also hooked to the tension roller 48, and by adjusting the position of the tension roller 48 (the position with respect to the radial direction of the accommodation hole 7), The tension can be adjusted.

  Note that one of the three crankshafts 3 (the crankshaft at the lower right in FIG. 1 in the present embodiment) is a drive crankshaft to which supply power is input from the outside (or output recovery power to the outside) The remaining two are 3A, and the other two are driven crankshafts 3B that do not directly perform such input (or output). Although the details will be described later, when the scroll fluid machine 1 is an air compressor, the supply power is externally supplied to the drive crankshaft 3A (that is, the power is input), and accordingly, the driven crank is rotated via the rotation synchronization mechanism 45. While rotating the shaft 3B, the orbiting scroll 2 is turned. On the other hand, when the scroll fluid machine 1 is a steam expander, the orbiting scroll 2 is swirled by the supplied steam, and the crankshafts 3 are rotated via the rotation synchronization mechanism 45 to give the recovery crankshaft to the drive crankshaft 3A. Power (that is, power is output).

  Each crankshaft 3 is provided with a weight balancer 49 for smooth rotation of the orbiting scroll 2. In the present embodiment, weight balancers 49 are respectively provided at the lower end portion of the upper main shaft portion 34 and the upper end portion of the large diameter portion 35 a of the lower main shaft portion 35.

  Each fixed scroll 5 is provided with one or more plate-shaped fixed wraps 50 on one side of the disk-shaped end plate 20 perpendicularly to the plate surface. Specifically, in FIG. 2, the upper fixed scroll 5 is provided with a fixed wrap 50 downward on the lower surface of the end plate 20, and the lower fixed scroll 5 is provided on the upper surface of the end plate 20. The fixing wrap 50 is provided upward. At this time, the fixing wrap 50 is provided in the number, shape and size corresponding to the turning wrap 6 and formed in a spiral shape of an involute curve from the center to the outer periphery of the end plate 20 . In each fixed wrap 50, the gap between the end portion 20 extending from the end plate 20 (the lower end of the upper fixed wrap 50, the upper end of the lower fixed wrap 50) and the base portion 16 of the orbiting scroll 2 is filled. A tip seal 51 is detachably provided along the spiral.

  Each fixed scroll 5 is provided with a cylindrical outer peripheral wrap 52 so as to surround the fixed wrap 50. Specifically, in FIG. 2, the upper fixed scroll 5 is provided with an outer peripheral wrap 52 downward on the lower surface of the end plate 20, and the lower fixed scroll 5 is provided on the upper surface of the end plate 20. The circumferential wrap 52 is provided upward. The height (extending dimension from the end plate 20) of the outer circumferential wrap 52 substantially corresponds to the height (extending dimension from the end plate 20) of the fixed wrap 50. In each of the outer peripheral wraps 52, one or more annular outer seals 52A are attached to and removed from the tip end extended from the end plate 20 (the lower end of the upper outer peripheral wrap 52, the upper end of the lower outer peripheral wrap 52) Possibly, it is provided along the circumferential direction.

  Each fixed scroll 5 is detachably provided above and below the housing member 4 in a state in which the fixed wrap 50 is engaged with the turning wrap 6. Specifically, the outer periphery of the end plate 20 is superimposed on the upper surface of the upper flange 15 of the housing member 4 in the upper fixed scroll 5, and the upper fixed scroll 5 is detachably fixed by a bolt 53. The lower fixed scroll 5 has the outer peripheral portion of the end plate 20 superimposed on the lower surface of the lower flange 15 of the housing member 4 and is detachably fixed by a bolt 53. Note that lock pins 55 are provided at a plurality of locations in the circumferential direction on the flange 15 of the housing member 4, and the lock pins 55 are inserted into pin holes provided in the end plate 20 of the fixed scroll 5. Positioning of the fixed scroll 5 with respect to the circumferential direction is performed.

  As in the case of the orbiting scroll 2, the fixed scroll 5 is also provided with the housing material from the fixed scroll 5 for protection of the upper bearing 36 and the lower bearing 37 provided in the housing material 4 (more specifically, prevention of grease breakage). Preferably, heat transfer to 4 is prevented. For that purpose, as shown in FIGS. 2 and 4, it is preferable that the fixed scroll 5 and the housing member 4 be overlapped via the second intermediate member 54 so as not to be in direct contact with each other.

  Specifically, the flange 15 of the housing member 4 and the end plate 20 of the fixed scroll 5 may be overlapped via the intermediate member 54. The intermediate member 54 may be in the form of a washer through which a bolt 53 for fixing the end plate 20 of the fixed scroll 5 to the flange 15 of the housing member 4 passes, or may be overlapped over the entire circumferential direction of the flange 15 of the housing member 4 It may be annular. Further, as in the case of the orbiting scroll 2, a heat insulating material and a spacer may be combined as the intermediate material 54. In any case, the intermediate material 54 is formed of a material having a thermal conductivity lower than that of the housing material 4.

  Then, the end plate 20 of the fixed scroll 5 is inserted into the opening hole 7A of the housing member 4 with a gap between the inner peripheral surface of the opening hole 7A and the outer peripheral surface of the end plate 20. In addition, the outer peripheral wrap 52 of the fixed scroll 5 is also inserted at the location of the flange 15 of the housing member 4 with a gap between the inner peripheral surface of the flange 15 and the outer peripheral surface of the outer peripheral wrap 52. Furthermore, in addition to the bolt 53 used for fixing the fixed scroll 5 to the housing member 4, preferably the lock pin 55 is also preferably formed of a material (here, stainless steel) having a thermal conductivity lower than that of the housing member 4. . In this manner, heat transfer from the fixed scroll 5 to the housing member 4 can be prevented, and protection of the upper bearing 36 and the lower bearing 37 can be achieved.

  By the way, in the present embodiment, the orbiting scroll 2 (the orbiting scroll main body 17 and the orbiting scroll base 18) is formed of an aluminum alloy as described above. Further, the fixed scroll 5 is also preferably formed of an aluminum alloy, similarly to the orbiting scroll 2.

  The chemical composition of the aluminum alloy constituting the orbiting scroll 2 and the fixed scroll 5 is Si: 8.0 to 11.0% by mass, Mg: 0.3 to 0.6% by mass, Mn: 0.3 to 0 .6 Al-Si-Mg-Mn based aluminum alloy containing 6% by mass, preferably containing 0.5% by mass or less of Cu and 0.7% by mass or less of Fe Used. For example, in the case where scroll fluid machine 1 is used as a steam expander, Cu, which causes corrosion resistance deterioration even when steam contains a condensate treating agent (amine compound or ammonia) for carbon dioxide gas neutralization, is used. By using an aluminum alloy having a low content of Fe and Fe, it is possible to effectively prevent the corrosion of the orbiting scroll 2 and the fixed scroll 5 which are portions in contact with steam. As a result, sufficient corrosion resistance can be provided in addition to the lightness and slidability required for the steam expander. Further, also when the scroll fluid machine 1 is used as an air compressor, sufficient corrosion resistance can be imparted in addition to lightness and slidability.

  In the present embodiment, for example, 0.25% by mass or less of Cu, 0.55% by mass or less of Fe, 0.25% by mass or less of Zn, and 0.10% or less as the above-described component conditions. Mass% or less, Ti is 0.20 mass% or less, Pb is 0.10 mass% or less, Sn is 0.05 mass% or less, Cr is 0.15 mass% or less, and the balance is made of Al and unavoidable impurities An aluminum alloy casting of AC4A according to JIS-H5202 which is an aluminum alloy is selected as a material of the orbiting scroll 2 and the fixed scroll 5. As a result, the content of Cu and Fe, which causes a decrease in corrosion resistance, can be further reduced to further improve the corrosion resistance. In addition, AlSi10Mg of ISO3522 can also be used as an aluminum alloy of AC4A equivalent.

  In addition, when the scroll fluid machine 1 is used as a steam expander, at least a portion of the orbiting scroll 2 and the fixed scroll 5 which forms an expansion chamber and comes into contact with steam has a hard alumite film (anodized film on its surface Preferably, the above-mentioned aluminum alloy (AC4A) is subjected to an alumite treatment to have a. Aluminum alloys can be protected with a hard alumite layer to provide chemical resistance.

  FIG. 5 is a schematic view showing a state in which the orbiting bearing 29 is attached to the bearing attachment hole 33 of the orbiting scroll 2 of FIG. Hereinafter, the holding structure of the orbiting scroll 2 to the eccentric shaft portion 8 of the crankshaft 3 will be described based on FIG. 2, FIG. 4 and FIG.

  First, the swing bearing 29 will be described. The pivot bearing 29 is a rolling bearing as the upper bearing 36 and the lower bearing 37 are. The rolling bearing constituting the turning bearing 29 is configured by being arranged in the circumferential direction between a substantially cylindrical inner ring 29a and an outer ring 29b which are concentrically arranged, and a large number of rolling elements 29c are held. As a result, in the turning bearing 29, the inner ring 29a and the outer ring 29b are made rotatable via the rolling elements 29c. The inner ring 29a and the outer ring 29b are collectively referred to as a bearing ring.

  In the swivel bearing 29, the inner ring 29a, the outer ring 29b and the rolling elements 29c are formed of steel. The rolling elements 29 c may be rollers (cylindrical bodies), but are typically balls (spherical bodies). More specifically, the orbiting bearing 29 is preferably a deep groove ball bearing, and the inner ring 29a, the outer ring 29b and the rolling elements 29c are made of high carbon chromium steel, hardened steel, stainless steel, high speed steel, or high frequency It is formed of hardened steel. As the high carbon chromium steel, for example, the symbols SUJ2, SUJ3, SUJ5, etc. defined in JIS G 4805 are used. For example, the symbols SCr420, SCM420 and the like specified in JIS G 4053 are used as the case-hardened steel (carburized steel). As stainless steel, for example, the symbol SUS440C defined in JIS G 4303 is used. As the high speed steel, for example, those specified in AMS 6491 (M50), AMS 5226 and the like are used. The induction hardened steel is a hardening of the bearing surface by induction hardening instead of carburizing and hardening of the case-hardened steel, and one having a chemical composition similar to that of the iron-hardened steel is used. By forming with these steel materials, it is possible to make a rolling bearing with high accuracy and long life.

  The orbiting bearing 29 is an expansion correction bearing in which a belt-like spacer 57 made of resin is attached to the outer peripheral surface of the outer ring 29 b. Specifically, as shown in FIG. 5, substantially rectangular concave grooves 29d are formed in two rows on the outer peripheral surface of the outer ring 29b so as to be vertically separated (in the axial direction of the turning bearing 29). An annular band-shaped spacer 57 is inserted into each of the recessed grooves 29d. The strip spacer 57 is an annular resin ring, and the cross section cut in the radial direction is formed in a substantially rectangular shape. The belt-like spacer 57 is provided with the inner peripheral portion thereof fitted in the recessed groove 29 d of the outer ring 29 b. In a state where the band-shaped spacer 57 is attached to the recessed groove 29d of the outer ring 29b, the outer peripheral portion of the band-shaped spacer 57 protrudes outward more than the outer peripheral surface of the outer ring 29b.

  Preferably, 90% or more of the thickness in the radial direction of the belt-like spacer 57 is accommodated in the concave groove 29d. As described later, the linear expansion coefficient of the resin material forming the band-like spacer 57 is set to be about 4 to 8 times larger than the linear expansion coefficient of the aluminum alloy forming the orbiting scroll 2. Therefore, in the radial thickness of the strip spacer 57, if the depth to be contained in the recessed groove 29d is less than 90%, the volume increase of the strip spacer 57 expands in the axial direction of the bearing when heated. And adjustment of the diametrical fitting gap may be insufficient.

  The strip spacer 57 is made of one or more resin materials selected from polyamide resin, polyacetal resin, polybutylene terephthalate resin, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and has a water absorption coefficient It is preferable that (ASTM D570) be 1% or less. The reason will be described later.

  As the polyamide resin, 9T nylon (abbreviation: PA9T, polyamide obtained by condensation polymerization of nonanediamine and terephthalic acid); 6T nylon (abbreviation: PA6T, polyamide obtained by condensation polymerization of hexamethylenediamine and terephthalic acid); Abbreviations: PA11, polyamide obtained by ring-opening condensation polymerization of undecanelactam; and 12 nylon (abbr .: PA12, polyamide obtained by ring-opening condensation polymerization of lauryl lactam) can be used. Also, when using the polyamide resins listed above, glass fiber reinforced 9T nylon is preferred.

  The orbiting scroll 2 is held by the eccentric shaft portion 8 of the crankshaft 3 via the orbiting bearing 29 having such a configuration. Specifically, the inner ring 29 a of the turning bearing 29 is press-fitted and fixed to the eccentric shaft portion 8 of the crankshaft 3. In the present embodiment, two pivot bearings 29 having the same shape are vertically stacked and press-fit into the eccentric shaft 8. At this time, the lower end surface of the inner ring 29a of the lower swing bearing 29 is in contact with the second step 3b. Then, since the upper end portion of the eccentric shaft portion 8 is a screw portion, the second retaining nut 56 is screwed into the screw portion. As a result, the inner ring 29 a of the pivot bearing 29 is fixed by being sandwiched between the second step 3 b and the retaining nut 56.

  On the other hand, in the orbiting bearing 29, the band-like spacer 57 of the outer ring 29 b is press-fitted and accommodated in the bearing attachment hole 33 (more specifically, the large diameter hole 33 a) of the orbiting scroll 2. Specifically, as shown in FIG. 5, assuming that the inner diameter of the bearing mounting hole 33 is D, the outer diameter of the orbiting bearing 29 (the outer ring 26b) is d, and the outer diameter of the strip spacer 57 is d1, d1> D The band-like spacer 57 in the relationship is tightly fitted to the bearing mounting hole 33. The outer diameter d of the orbiting bearing 29 is smaller than the inner diameter D of the bearing mounting hole 33 (d <D). Although the details will be described later, the relationship of d <D is also maintained by the temperature rise accompanying the use of the scroll fluid machine 1.

  A retaining ring 58 is fixed to the orbiting scroll base 18 at the upper surface of the circumferential side wall of the bearing mounting hole 33 by a bolt 59. The retaining ring 58 preferably restricts axial movement while allowing radial movement of the orbiting scroll 2 with respect to the outer ring.

  As shown in FIG. 1 and FIG. 2, the pair of fixed scrolls 5 is provided with a first opening 60 on the outer peripheral side, and a second opening 61 in the center. Pipe-shaped opening materials 62 and 63 are attached to the first opening 60 and the second opening 61, respectively. In addition, in FIG. 2, the second openings 61 shown at the top and bottom may be connected to each other by opening a through hole at the center of the substrate portion 16 of the orbiting scroll 2 as the case may be.

  Assembling of the scroll fluid machine 1 of the present embodiment is preferably performed as follows. That is, first, the lower bearing 37 is attached to the lower plate 12. On the other hand, each crankshaft 3 is attached to the orbiting scroll 2 via a orbiting bearing 29 with a band-like spacer 57. Then, each crankshaft 3 of the orbiting scroll 2 is fitted and attached to the lower bearing 37 of the lower plate 12. At that time, each crankshaft 3 is attached in a predetermined position (that is, in a state where there is no phase difference in which the position of the eccentric shaft portion 8 is aligned). Thereafter, the upper plate 11 is attached, and at this time, the upper bearing 36 is provided between the upper plate 11 and the crankshaft 3. Finally, the fixed scroll 5 may be fixed to the opening holes 7A of the upper plate 11 and the lower plate 12.

  Since the scroll fluid machine 1 of the present embodiment is configured as described above, for example, when used as an air compressor, the drive crankshaft 3A may be rotated (that is, power is input). For example, an output shaft of a motor (not shown) is directly connected to one main shaft portion 35 of the drive crankshaft 3A, that is, connected via a coupling.

  Thus, the orbiting scroll 2 can be turned relative to the fixed scroll 5. At this time, the motive power supplied to the drive crankshaft 3A is also transmitted to the driven crankshaft 3B via the rotation synchronization mechanism 45, and the three crankshafts 3 are synchronously rotated. When the orbiting scroll 2 is pivoted with respect to the fixed scroll 5, air is taken in from the first opening 60, and the air is compressed between the pivot wrap 6 and the fixed wrap 50 while the spiral is from the outer end to the inner end It can be moved to the side and discharged as compressed air from the second opening 61.

  On the other hand, when used as a steam expander, for example, the orbiting scroll 2 is rotated by steam from a boiler or the like, and rotational drive force is applied to the drive crankshaft 3A (that is, power is output). For example, an input shaft of a driven machine (machine driven by a steam expander) is directly connected to the drive crankshaft 3A, that is, connected via a coupling.

  And if steam is made to flow in from the 2nd opening 61, revolution scroll 2 will turn with power of steam, and steam will be discharged from the 1st opening 60, expanding. Thereby, the rotational drive force of the orbiting scroll 2 can be taken out from the drive crankshaft 3A as the recovery power. Also in this case, the driven crankshaft 3B rotates in synchronization with the drive crankshaft 3A via the rotation synchronization mechanism 45.

  As described above, according to the scroll fluid machine 1 of the present embodiment, the orbiting scroll 2 made of aluminum alloy is held by the eccentric shaft 8 of the crankshaft 3 via the steel orbiting bearing 29. By forming the orbiting scroll 2 of aluminum alloy, the weight of the scroll fluid machine 1 can be reduced. Even when the orbiting scroll 2 is formed of an aluminum alloy, as described below, the outer ring 29b of the orbiting bearing 29 is stabilized by stabilizing the interference of the band-shaped spacer 57 provided on the outer peripheral surface of the outer ring 29b of the orbiting bearing 29. Creep can be prevented.

That is, first, as described above, the orbiting bearing 29 is an expansion correction bearing in which a resin-made band-like spacer 57 is attached to the outer peripheral surface of the outer ring 29 b, and is press-fit into the bearing mounting hole 33 of the orbiting scroll 2. That is, when the outer diameter of the strip spacer 57 is d1 and the inner diameter of the bearing mounting hole 33 is D, the strip spacer 57 in the relationship of d1> D is tightly fitted to the bearing mounting hole 33. The linear expansion coefficient (2-2.3 × 10 ⁻⁵ / ° C.) of the aluminum alloy forming the orbiting scroll 2 is the linear expansion coefficient (1.1 ̃1.3 × 10 ⁻⁵ ) of the steel forming the orbiting bearing 29. As the temperature increases with the use of the scroll fluid machine 1, the gap between the outer diameter d of the outer ring 29b and the inner diameter D of the bearing mounting hole 33 increases. However, since the linear expansion coefficient (8 to 16 × 10 ⁻⁵ / ° C.) of the synthetic resin forming the strip spacer 57 is further larger than the linear expansion coefficient of the aluminum alloy of the orbiting scroll 2, the thermal expansion of the aluminum alloy occurs when the temperature rises. The expansion can be reliably followed, and the interference ((d1-D) / 2) of the strip spacer can be stabilized. Therefore, even when the orbiting scroll 2 is formed of an aluminum alloy, creep of the outer ring 29 b of the orbiting bearing 29 attached to the crankshaft 3 can be prevented.

  Further, the belt-like spacer 57 of the present embodiment is made of the above-described synthetic resin, so that the hardness is such that the centrifugal force is not caused by the turning of the turning scroll 2 (specifically, 50 to 120 in R scale of Rockwell hardness). Since the degree (M scale, about 65 to 90) is included, the interference of the band-like spacer 57 can be stabilized including the start and stop.

  Furthermore, since this synthetic resin is formed of a material having a low water absorption rate, it is possible to suppress changes in fit due to swelling and also to prevent cracking and deformation. Therefore, the operation can be stabilized even when used in a water addition type (water lubricated type) air compressor or a steam expander.

  For example, in a water addition type air compressor, operation is performed while adding water instead of lubricating oil for air tightness and cooling of the compression chamber. In this case, if the outer seal 52A of the fixed scroll 5 is degraded, water may leak out of the compression chamber and enter the bearing portion. Therefore, if a material having a high water absorption rate is used for the strip spacer 57, the water may In the case where the band-shaped spacer 57 intrudes, the swelling of the band-like spacer 57 causes a change in fit, cracking, deformation, etc., and normal operation is inhibited. However, such a disadvantage can be prevented by using a material having a low water absorption rate for the strip-like spacer 57 as in this embodiment. Further, in the steam expander, steam condensation water is generated during stoppage, but even if water leaks out from the expansion chamber and enters into the bearing portion, it is possible to prevent the inconvenience caused to the strip spacer 57.

  The scroll fluid machine 1 of the present invention is not limited to the configuration of the above embodiment, but can be appropriately modified. In particular, the scroll fluid machine 1 used as an air compressor or a steam expander, wherein (a) the orbiting scroll 2 is provided with the orbiting wrap 6 on both sides of the substrate portion 16, and (b) the orbiting scroll 2 is accommodated. (D) a pair of fixed scrolls 5 fixed to the housing member 4 so as to sandwich the orbiting scroll 2; (d) the orbiting scroll 2 (E) The eccentric shaft 8 is eccentric between the main shaft portions 34 and 35 arranged on the same axis (c) Fixed; by holding the orbiting scroll 2 on the eccentric shaft portion 8 via the rolling bearing (the orbiting bearing 29). (F) The orbiting scroll 2 is formed of an aluminum alloy, and a bearing mounting hole 33 is provided on the outside of the orbiting wrap 6, (g) a rolling bearing (g) The orbiting bearing 29) is an expansion correction bearing in which the races 29a and 29b and the rolling elements 29c are formed of steel, and the outer circumferential surface of the outer ring 29b is additionally provided with a strip spacer 57 made of resin. If the bearing is press-fit into the bearing mounting hole 33 and accommodated, the other configuration can be appropriately changed.

  For example, in the embodiment described above, the number of crankshafts 3 is three, and the orbiting scroll base 18 has a substantially triangular shape, but the number of crankshafts 3 is four or more, and accordingly, the shape of the orbiting scroll base 18 In addition to a substantially square shape and other polygons, a substantially circular shape may be used. Even in that case, it is preferable to synchronously rotate one of the plurality of crankshafts 3 as the drive crankshaft 3A and the remaining one as the driven crankshaft 3B via the rotation synchronization mechanism 45.

1 scroll fluid machine 2 orbiting scroll 3 crankshaft (3A: drive crankshaft, 3B: driven crankshaft)
DESCRIPTION OF SYMBOLS 4 housing material 5 fixed scroll 6 turning lap 8 eccentric shaft part 16 board part 17 turning scroll main body 18 turning scroll base 20 end plate 29 turning bearing (29a: inner ring, 29b: outer ring, 29c: rolling element, 29d: recessed groove)
33 Bearing mounting hole (33a: large diameter hole, 33b: small diameter hole)
34 main shaft portion 35 main shaft portion 36 upper bearing 37 lower bearing 45 rotation synchronization mechanism 46 timing belt 50 fixed wrap 52 outer peripheral wrap 57 band spacer

Claims (5)

A scroll fluid machine used as an air compressor or a steam expander, comprising:
An orbiting scroll provided with orbiting wraps on both sides of the substrate portion;
A housing material in which the orbiting scroll is accommodated;
A pair of fixed scrolls provided with fixed wraps that mesh with the turnable wraps and fixed to the housing material so as to sandwich the turnable scrolls;
Crankshafts arranged at equal intervals at three or more locations in the circumferential direction of the orbiting scroll,
In the crankshaft, an eccentric shaft portion is eccentrically provided between main shaft portions arranged on the same axis; in the main shaft portions on both sides, rotatably supported by the housing material; and a rolling bearing on the eccentric shaft portion. By holding the orbiting scroll via, the orbiting scroll is pivotably held with respect to the fixed scroll,
The orbiting scroll is formed of an aluminum alloy, and a bearing mounting hole is provided on the outside of the orbiting wrap.
The rolling bearing is an expansion correction bearing in which a bearing ring and rolling elements are formed of steel and a strip spacer made of resin is attached to the outer peripheral surface of the outer ring.
The scroll fluid machine is characterized in that the expansion compensation bearing is press-fit and accommodated in the bearing mounting hole. The orbiting scroll is Al-Si-Mg-Mn containing Si: 8.0 to 11.0 mass%, Mg: 0.3 to 0.6 mass%, and Mn: 0.3 to 0.6 mass%. Formed of aluminum alloy,
The scroll fluid machine according to claim 1, wherein the aluminum alloy contains 0.5% by mass or less of Cu and 0.7% by mass or less of Fe. The belt-like spacer is made of one or more resin materials selected from polyamide resin, polyacetal resin, polybutylene terephthalate resin, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the water absorption rate Is 1% or less. The scroll fluid machine according to claim 1 or 2, wherein The rolling bearing is a deep groove ball bearing; and the bearing ring and the rolling element are formed of high carbon chromium steel, hardened steel, stainless steel, high speed steel, or induction hardened steel. The scroll fluid machine according to any one of claims 1 to 3. The scroll fluid machine according to any one of claims 1 to 4, wherein a plurality of the expansion correction bearings are provided on the eccentric shaft portion.

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