JP3539189B2 - Scroll fluid machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a orbiting positive displacement compressor that compresses gas while reducing the volume of a compression working chamber. In particular, a crescent-shaped compression chamber is formed by a spiral scroll and a fixed scroll member. The present invention relates to a scroll fluid machine in which the crescent-shaped compression chamber compresses gas while reducing the volume by the orbiting motion of the orbiting scroll.
[0002]
[Prior art]
The scroll compressor, as conventionally known, explains the basic operating principle.This compressor is a revolving machine that has a wrap formed upright in a spiral shape with a continuous curve such as an involute curve on the head plate. The fixed scroll members are engaged with each other, and one of the scroll members is relatively rotated with respect to the other scroll member while restraining the scroll members from rotating. It is compressed. As an example of this type of scroll compressor, Japanese Patent Application Laid-Open No. 8-128395 discloses an embodiment of an oil-free air compressor. On the other hand, Japanese Patent Application Laid-Open No. 8-86293 discloses a scroll compressor for an air conditioner. Is shown. The general scroll wrap shape in this type of scroll compressor is formed in a spiral shape with substantially the same thickness from the start to the end of the turning and the fixed scroll. However, at the very slight starting portion of the winding at the center, the tip may be pointed at an acute angle due to various design reasons, or may be formed into a circular arc to form a bulb. In addition, the end portion of the winding may be designed so that the wrap is continuous with the wall portion of the main body particularly in the case of the fixed scroll. Therefore, in the known scroll, the scroll wrap is designed so that the thickness of the scroll wrap is practically equal in other portions except for the slightly wound start and end portions as described above.
[0003]
Since the crescent-shaped compression chamber forms one compression chamber at a spiral angle of 360 degrees, the seal length between the end of the scroll wrap at the center and the end plate of the scroll facing the other is short, and the other outer periphery is formed. The seal length at is longer. Therefore, when the amount of leakage is compared solely based on the seal length, the central portion has a feature that it is less likely to leak, and the outer peripheral portion is more likely to leak.
[0004]
In general, from the above-mentioned compression principle, the pressure at the center of the spiral is high, and the pressure at the outer periphery is low. As a result, deformation due to pressure tends to be large in the central portion. On the other hand, the gap between the wraps at the multiple seal points on the side of the scroll wrap is kept very small in order to maintain high compression efficiency. There is a possibility that the scrolls and the fixed scrolls come into contact with each other on the wrap side surfaces of the scrolls.
[0005]
According to a known technique described in Japanese Patent Application Laid-Open No. Sho 60-252102, measures for the above technique are shown. This prior art is characterized in that the thickness of the wrap of the orbiting and fixed scroll can be continuously changed according to the winding angle of the spiral wrap, and as an example, the thickness of the scroll wrap at the center of the scroll is provided. There is a scroll fluid machine in which the thickness is increased or only the outer scroll wrap is configured to be thick, and a scroll fluid machine capable of exhibiting optimum performance according to each application is provided.
[0006]
[Problems to be solved by the invention]
According to the known technique described above, if the thickness of the scroll wrap at the center is increased, deformation of the scroll wrap due to the compressed gas force is prevented at the center of the scroll, and the thickness of the scroll wrap at the outer periphery is increased. It is stated that if the sealing performance is improved.
[0007]
By the way, when the scroll fluid machine according to the related art is used as an oil-free air compressor, even when the gap between the scroll wraps is properly managed, the gap becomes small. There was a problem of contact.
[0008]
Further, when this scroll fluid machine is used as a refrigerant compressor for refrigeration and air conditioning, there is a problem that the scroll wraps may come into contact depending on the operating conditions even if the gap between the scroll wraps is properly managed as described above. there were.
[0009]
On the other hand, if the gap between the scroll wraps is set to such a value that the wraps do not contact each other, there is a problem that the performance as a scroll fluid machine is reduced.
[0010]
An object of the present invention is to provide a scroll fluid machine that maintains the performance as a scroll fluid machine as much as possible while suppressing contact between scroll wraps.
[0011]
[Means for Solving the Problems]
The above purpose isA pair of fixed scrolls in which spiral scroll wrap surfaces are arranged in parallel with each other facing each other, and spiral scroll wraps provided between the two fixed scrolls and provided on both sides of the end plate are respectively provided on the fixed scroll wraps. In a double-toothed scroll fluid machine including an orbiting scroll formed so as to mesh with each other and a suction port provided on an outer peripheral portion of the scroll wrap on the fixed scroll side, a winding start portion and a winding end portion of each scroll wrap. Alternatively, when the scroll fluid machine is assembled by making the thickness of the other scroll wrap portions except for the portion adjacent to the suction port substantially equal to each other, at least the orbiting scroll of the fixed scroll wrap that directly contacts the suction gas sucked from the suction port. The fixing at a position off the end of the wrap winding The minimum radial clearance between the scroll wraps being formed by engagement of the orbiting scroll wrap to crawl lap inside, larger than the minimum radial clearance in the other scroll wrap portionIt is achieved by doing.
[0012]
Here, the inner curve of the fixed scroll wrap at a position deviated from the end of the orbiting scroll wrap winding of the fixed scroll wrap directly contacted by the suction gas sucked from the suction port may be formed into a curve depressed outward, or By shifting the outer curve of the orbiting scroll wrap corresponding to the portion to the inside and reducing the wrap thickness of the portion, the minimum radial gap between the wraps of the portion can be increased.
[0013]
Further, in addition to the above-described configuration, the fixed scroll wrap inner curve at the winding end portion of the fixed scroll wrap may be formed as an outwardly concave curve, or the orbiting scroll wrap outer curve corresponding to that portion may be moved inward. If the minimum radial gap between the wraps of the portion is formed large by forming the curved shape, the contact between the wraps in this portion can be prevented.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A basic configuration of a compressor according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view showing the entire structure of an outer peripheral drive type compressor of a type in which a plurality of crankshafts are arranged on the outer peripheral portion of the end plate of the orbiting scroll to cause the orbiting scroll to orbit. FIG. 2 is an external view showing a side surface of the compressor of FIG. FIG. 3 is a cross-sectional view showing the meshing state of the wraps in the cross-sectional view taken along the line AA of FIG. 1, and shows a state where a compression working chamber is formed by the wraps of the orbiting scroll and the fixed scroll.
[0015]
In FIG. 1, in the outer peripheral drive type scroll compressor, a fixed scroll 2 having a scroll wrap 2b formed in the same manner as a fixed scroll 1 having a scroll wrap 1b formed in a spiral shape is arranged in parallel, and between them. The orbiting scroll 3 having scroll wraps 3b and 3c which are also spirally formed on both sides of the end plate 3a meshes with the respective fixed scrolls to form compression working chambers 14 and 15 on both sides of the end plate 3a of the orbiting scroll 3. . These compression working chambers are formed in a crescent shape by both scroll wraps as shown in FIG. In a scroll compressor, such a crescent-shaped compression working chamber is formed symmetrically with respect to a central axis, and a pair of chambers is formed with substantially the same volume. The compression working chamber is configured so that its volume is gradually reduced from the outer peripheral part toward the center, and such that the compression working chamber is continuously moved to the central part with the orbital movement of the orbiting scroll 3. Has become.
[0016]
As shown in FIG. 1, a wrapping tip of each of the fixed scroll 1, the fixed scroll 2, and the orbiting scroll 3 has an inorganic material such as carbon or a composite material mainly composed of tetrafluoroethylene resin or polyimide resin. The tip seals 1c, 2c, 3d, and 3e formed by spirals are respectively provided along the spirals. When shown in a plan view as shown in FIG. 3, the tip seal 1c shown in FIG. Although it is arranged, in this state, it is divided into a plurality of pieces in consideration of the extension of the resin due to heat along the spiral. This chip seal does not need to be divided unless there is a particular problem in function and performance. By dividing, it is possible to improve the moldability, assemblability, seal performance and reliability of the chip seal. I can do it. The tip seals 3d and 3e provided at the tip of the wrap of the orbiting scroll abut against the end plates 1a and 2a of the fixed scroll, respectively.
[0017]
Further, as shown in FIG. 1, the orbiting scroll head plate 3a is provided with a flow path 8 so that the upper and lower compression working chambers 14 and 15 communicate with each other substantially at the center of the head plate 3a. On the other hand, as shown in FIG. 3, a plurality of suction ports 22, 23 are provided so as to communicate with the outer peripheral portion of the scroll portion of the fixed scroll 1. As shown in FIG. 2, the suction ports 22 and 23 have a flange structure so that suction pipes (not shown) are respectively connected outside the fixed scroll 2. Returning to FIG. 3, the suction gas flowing from each suction port 22, 23 flows into the suction chambers 16, 16 'independently of the outside air. A dust trap 24 is provided on the outer peripheral portion of the fixed scroll wrap 1b to prevent the outside air and the suction chamber 16 from communicating with each other. This dust trap is formed in an annular shape, and as shown in FIG. 1, a dust seal 24a configured like a tip seal at the tip of the wrap is provided on the tip end face of the dust trap 24 in the concave groove on the tip end face of the dust trap 24. And has a sealing function while being in contact with the end surface of the orbiting scroll. The dust scroll 25 and the dust seal 25a are similarly provided on the fixed scroll 2 disposed on the opposite side to prevent the outside air and the suction chamber from communicating with each other.
[0018]
As shown in FIG. 1, a drive shaft 4 having an eccentric portion is provided on the outer peripheral portion of the end plate of the orbiting scroll 3, and an auxiliary drive shaft 5 having an eccentric portion of the same eccentric amount is arranged. Are rotatably engaged via bearings 11a and 11b. In this engagement portion, an elastic support portion 13 is provided on the auxiliary drive shaft 5 to absorb a thermal expansion difference between the orbiting scroll 3 and the fixed scroll 1 or 2 and prevent an excessive load from acting on the auxiliary drive shaft 5 or the like. Is provided. The elastic member 13 is provided on the outer peripheral portion of the rolling bearing 11b, and is made of an annular resin or rubber, engineering plastic, metal spring, or the like, and is connected to the drive shaft 4 and the auxiliary drive shaft 5 in a linear direction. To absorb the stress. In any case, the orbiting scroll 3 is rotatably supported by a plurality of crankshafts. When the drive shaft 11a rotates, the orbiting scroll 3 is prevented from rotating, and the orbiting scroll 3 has a radius corresponding to the eccentric amount of the eccentric shaft. Exercise is brought.
[0019]
Although the fixed scrolls are arranged as a pair, the outer shapes are almost the same, so only the configuration on one side will be described here. The fixed scroll 1 is provided with a discharge port 9 substantially at the center thereof, and a radiation fin 1d is provided on the outer surface near the discharge port 9 of the fixed scroll 1. In order to obtain a large amount of heat exchange in the radiation fin 1d, a cooling air flow path is formed around the fin 1d by the cover 6a. Although the heat radiation fins 2d are formed in a straight line as shown in FIG. 2, if necessary, the heat radiation fins 2d may be divided into a plurality according to the amount of heat radiation, or may be formed into a wave shape or a substantially square shape. You can do it.
[0020]
On the other hand, as shown in FIG. 1, a plurality of cooling holes 26 for air cooling the orbiting scroll 3 are provided on the end surface of the orbiting scroll 3 between the end plates 3a of the orbiting scroll 3. Further, as shown in FIG. 3, air for cooling also flows inside the compressor, and the direction of the flow is indicated by an arrow 27 in the figure. The cooling air 27 flows in from the upper part in FIG. 3 and flows inside the fixed scroll, but is isolated from the compression chamber 14 and the suction chamber 16 by the dust wrap 24. Therefore, the cooling air 27 can suitably cool the periphery of the drive shaft, the bearing, the outer peripheral portion of the orbiting scroll, and the fixed dust trap.
[0021]
As shown in FIG. 3, the outer periphery of the fixed scroll 2 has a flange portion 2e, and the outer periphery of the fixed scroll 1 is also provided with a flange portion 1e (as shown in FIG. 1). The fixed scrolls 1 and 2 are connected to each other at the flange portions 1e and 2e by bolts or the like. At the time of coupling, the positioning means 19 for adjusting the relative positions of the fixed scrolls is assembled while maintaining the positional relationship between the fixed scrolls 1 and 2 and the orbiting scroll 3 properly. At the same time when the orbits 15 are formed, the orbiting scroll 3 can smoothly orbit.
[0022]
In FIG. 1, the drive shaft 4 is supported in a state where a part thereof is axially fixed by a rolling bearing 10 a fixed to a fixed scroll 2 by a ring-shaped pressing plate 41. It is rotatably engaged with a bearing 12a fixed to the other fixed scroll 1. Further, a holding plate 42 is provided to fix the bearing 12a to the fixed scroll 1. In the drawings, the holding plate 42 is shown as being formed in a ring shape, but may be formed in a bag shape. Further, balance weights 17a and 17b are fixedly arranged on the drive shaft 4 in order to cancel the imbalance caused by the orbiting movement of the orbiting scroll 3. On the other hand, the auxiliary drive shaft 5 located on the opposite side symmetrically to the drive shaft 4 also has the shaft fixed in the axial direction by the rolling bearing 10b fixed to the fixed scroll 2 by the ring-shaped pressing plate 43. The auxiliary drive shaft 5 is rotatably engaged with a bearing 12 b fixed to the other fixed scroll 1. Further, a holding plate 44 is provided to fix the bearing 12b to the fixed scroll 1. Further, balance weights 18a and 18b are also fixedly disposed on the auxiliary drive shaft 5 in order to cancel the imbalance caused by the orbiting movement of the orbiting scroll 3.
[0023]
A pulley 21 is provided on the drive shaft 4 via key means for preventing relative slippage, and rotational power is supplied from another power source installed. Further, the drive shaft 4 and the auxiliary drive shaft 5 are connected by a timing belt 7 via toothed pulleys 20a and 20b provided on the respective shafts so as to maintain the synchronization of rotation.
[0024]
As described above, the fixed scrolls 1 and 2 and the orbiting scroll 3 are each made of a light material having good heat conductivity as represented by an aluminum alloy or the like. Further, in order to provide a non-lubricated compressor, it is particularly preferable to apply an aluminum alloy containing a large amount of silicon. Furthermore, to improve lubricity during wrap contact or to provide a highly reliable non-lubricating compressor against seizure during contact, almost all of the side and bottom surfaces of the scroll wrap are compatible with aluminum alloy A surface treatment such as an anodic oxide film treatment can be performed.
[0025]
FIG. 4A is a plan view showing an embodiment in which the present invention is applied to the fixed scroll 2. The scroll wrap 2b is formed in a spiral shape, and the thickness of the wrap is almost equal except for a part. FIGS. 4 (2) and 4 (3) are enlarged views of the wrap. The scroll wrap 2b spirally formed by the involute curve has the same wrap thickness in design except for the P portion, the Q portion, and the R portion. However, since the center R portion at the beginning of the winding is formed in an arc shape so that the scroll wrap of the orbiting scroll meshing with the same does not interfere with the orbital movement, the wrap is irrespective of the present invention. The thickness changes greatly and is formed in a wedge shape.
[0026]
The wrap facing the suction port 22 is a wrap of the orbiting scroll as shown in FIG. 3, and the wrap facing the suction port 23 is a wrap of the fixed scroll. Therefore, the portions of the wrap affected by the temperature of the suction gas on the fixed scroll side are the P portion and the Q portion as shown in FIG. In the portion P on the fixed scroll side, the outside of the wrap is directly cooled by the suction gas entering from the suction port 23, so that the wrap itself is locally kept at a low temperature. On the other hand, the scroll wrap existing inside is kept at a high temperature by the heat of compression. At such high temperatures, the scroll expands in the direction of increasing radius as a whole. The amount of deformation is such that the orbiting scroll is provided inside the fixed scroll, the fixed scroll is harder to heat up than the orbiting scroll due to the cooling of the outer peripheral portion described above, and the fixed scroll is cooled by the intake gas as described above. Therefore, the orbiting scroll is larger than the fixed scroll. For this reason, in a scroll wrap having only a basic curve and a constant thickness, there is a high possibility that the outer curve of the orbiting scroll contacts the fixed inner curve in the vicinity of the P portion and the Q portion. If these wraps come into contact with each other, it will generate abnormal noise, bite the scroll parts, and in the worst case, break the wrap, which may lead to poor reliability.
There is a problem.
[0027]
In order to avoid this contact, the contact between the two wraps can be prevented by making the revolving circle of the revolving scroll smaller (reducing the revolving radius) than the inscribed circle between the wraps of the fixed scroll. For example, if the difference between the radius of the inscribed circle of the fixed scroll wrap of the oil-free scroll fluid machine described above and the orbital radius of the orbiting scroll is 180 μm, contact between the two wraps can be prevented.
[0028]
However, if this method is used to prevent contact, leakage from the scroll wrap other than the P and Q parts described above increases, that is, the compressed air in the working chamber near the discharge port leaks into the low-pressure working chamber. Once compressed air is compressed again, the amount of heat generated increases, causing a problem that the overall adiabatic efficiency of the compressor is reduced and desired performance cannot be obtained.
[0029]
In order to solve this contradictory problem, in this embodiment, the thickness of the wrap of the fixed scroll is partially reduced. This will be described below. FIGS. 4 (2) and (3) show enlarged portions P and Q. FIG. In FIG. 4 (2), as shown in the portion P in FIG. 3, the direct contact of the suction gas is at a position off the end of the wrap winding of the orbiting scroll (a position where the orbiting scroll wrap does not exist). 2_boApplies the basic curve as it is, the inner curve 2_biIs outward δ_s1Only a concave curve is applied.
[0030]
That is, the inner curve 2_biIs the surface facing the outer curve of the orbiting scroll wrap present inside. In this way, by reducing the thickness of a part of the wrap to reduce the thickness, it is possible to prevent the sides of the wrap from contacting each other. At this time, the amount of reduction of the wrap thickness should be appropriate for the amount of deformation corresponding to the suction temperature difference generated throughout the year by the scroll fluid machine for both the air compressor and the air conditioner compressor. The contact can be suitably prevented. That is, in an air compressor, it is common to take in outside air and compress it to a high pressure. In this case, however, the outside air often fluctuates greatly throughout the year, depending on the region of use, and day or night. For example, according to the science chronology, even in the Kanto region of Japan, the average temperature difference between summer and winter is about 20 degrees, and the maximum temperature difference is about 40 degrees. Since the outside air flowing in from the inlet part directly collides with the scroll wrap, the wrap at the collision part is locally cooled.
[0031]
As a result, a large difference occurs in the amount of deformation of the scroll wrap between summer and winter. In particular, since the intake air temperature becomes extremely low in winter, a large difference in the amount of thermal deformation occurs between the wraps of the P portion of the orbiting scroll 3 and the fixed scroll. The contact between the wraps due to the thermal deformation and the local cooling is suppressed. However, as described above, if the clearance between all the wraps is increased, the performance as a compressor is reduced.
[0032]
Then, when the gap between the wraps, which had been 180 μm, was reduced to 60 μm and an experiment was performed, it was found that the laps were in contact at the P and Q portions. The range of the contact portion was about 50 degrees to 90 degrees as viewed from the center of the scroll. This cannot prevent lap-to-lap contact.
[0033]
To solve this problem, the P and Q portions were reduced in thickness as described above. The thinning amount δs1 did not come into contact when the interval between the wraps was 180 μm, but did come in contact when it was 60 μm, so the difference was about 120 μm, about 0.1 mm. Since the data of the interval between the laps is not large, the thickness reduction Δs1 can be set to 0.1 mm or less depending on the minimum non-contact interval. The opening angle θ1 of the range of the thinned portion is within 90 degrees when viewed from the center of the scroll, similarly to the contact range. Since this value also depends on the interval between laps, it may be about 50 degrees depending on the value.
[0034]
FIG. 4 (3) shows the wrap end portion of the wrap. As described above, the outer wrap curve 2bo uses the basic curve, but the inner wrap curve 2bi has only the dimension δs2 with respect to the basic curve. A concave curve is applied. This portion is cooled by the intake port 22 and the portion extending from the end of the winding to the inside by θ2 is reduced in thickness. This angle θ can be set at about 90 degrees or less when viewed from the center of the scroll. In addition, the wall thinning amount δs2 can be set according to the suction temperature difference that can occur throughout the year as described above. These reasons are the same as above.
[0035]
In this way, by configuring and disposing the partially reduced wrap on the fixed scroll side, the wrap of the other orbiting scroll 3 can be formed by a basic involute curve having a constant thickness. As described above, if the present invention is applied to at least one of the fixed scroll and the orbiting scroll, the contact of the wrap can be prevented for a year.
[0036]
Next, a case where the present invention is applied to the orbiting scroll side for the compressor shown in FIG. 1 will be described with reference to FIG. FIG. 5 is a plan view of the orbiting scroll 3 and shows the shape as viewed from the timing belt side in FIG. The configuration of the orbiting scroll 3 will be additionally described. The orbiting scroll 3 includes a head plate 3a, a wrap portion 3b, and bearing mounting portions 51 and 52 on the outer periphery of the head plate. 5 is rotated by 180 degrees with respect to the direction of FIG. 1 for convenience of illustration, and the main bearing mounting portion is 51 and the sub bearing mounting portion is 52. A plurality of communication holes 50 are provided in the end plate 3a of the orbiting scroll at substantially 180-degree intervals. The communication hole 50 is provided so as to balance the pressures of the two compression working chambers 14 and 15 formed with the end plate 3a therebetween as much as possible.
[0037]
Hereinafter, an embodiment of the present invention in the orbiting scroll 3 will be described. The scroll wrap 3b has a portion having a constant thickness and a portion configured to be thinner. The center portion D of the spiral wrap is formed with a circular arc from the start point and the outer curve is formed with an involute curve as in the description of the fixed scroll 2, so that the tip portion has a wedge-shaped tooth shape.
[0038]
Part A, part B, and part C in FIG. 5 will be described in detail. These portions are in the wrap positions where the portions A and C just face the inlets 22 and 23 as can be inferred from FIG. A portion B is a wrap portion of the orbiting scroll 3 which is located inside the fixed scroll wrap, ie, has a positional relationship relative to the portion P in FIG. Therefore, these portions A, B, and C are portions that are greatly affected by the temperature of the intake air, and are where the amount of thermal expansion is reduced by being cooled. Each lap is formed to be thinner than other portions. FIGS. 5 (2), (3) and (4) are enlarged views of these.
[0039]
FIG. 5 (2) is an enlarged view of the portion A, and the point inside the terminal end forms the maximum sealed volume when meshing with the fixed scroll. Therefore, the inner curve 3bi is actively cooled by the suction gas. As a result, as in the case of the fixed scroll described above, there is a high possibility that the inner curve 3bi comes into contact with the outer curve of the fixed scroll. In order to prevent this, the inner curve 3bi is shifted to the outside by cutting off the inner curve 3bi by δr1. The wrap thickness is reduced. The range α1 for reducing the wrap thickness can be set to 90 degrees or less as the scroll center angle. These reasons are the same as in the first embodiment. You.
[0040]
FIG. 5C is an enlarged view of a portion B. As described above, since this portion is a portion that comes into contact with the inner curve of the fixed scroll wrap 2b, the amount of thermal expansion on the fixed scroll side is reduced. Therefore, in order to prevent contact during operation, the outer curve 3bo is changed by δr2. Moved inward to reduce wrap thickness. Also in this case, the range α1 in which the wrap thickness is reduced can be set to 90 degrees or less as the scroll center angle. These reasons are the same as in the first embodiment.
[0041]
FIG. 5D is an enlarged view of a portion C. This part is based on FIG.You can understandAs described above, this portion corresponds to the vicinity of the end of the fixed scroll wrap. Therefore, similarly to the part A, it is also a part that forms another maximum sealed space with the end of the fixed scroll winding. The corresponding fixed scroll corresponds to the portion corresponding to the suction port 22 as described with reference to FIG. 3, and also the portion where the dust lap is formed at the same time. For this reason, the fixed scroll side is always cooled by the air flowing through the outer periphery of the dust trap, and on the other hand, is also cooled by the suction gas, so that the thermal expansion amount of this portion is reduced. However, since the temperature inside the portion C of the orbiting scroll 3 is kept high by the heat of compression from the inside of the spiral, the amount of thermal expansion is large. To avoid contact due to thermal expansion difference in such a stateFig. 5 (4)As shown in the figure, the wrap thickness is set to be thin by moving the wrap outer line 3bo inward by δr3.
[0042]
The wrap thickness reduction amounts δr1, δr2, δr3 shown in FIG. 5 can occur throughout the year when the compressor is operated as an air compressor, as set on the previous fixed scroll side. In consideration of the change in temperature, the temperature is set at least according to the temperature difference between winter and summer.
[0043]
Further, in the above-described embodiment, when the partial wrap thickness is reduced, it is shown that the reduction is performed on one of them in accordance with the annual temperature difference, but the thickness reduction δs1, δs2 performed on the fixed scroll is shown. In consideration of the thickness reductions δr1, δr2, δr3 performed on the orbiting scroll and the orbiting scroll, about half of these amounts may be applied to the fixed scrolls 1 and 2 and the orbiting scroll 3. In this case, there is a disadvantage that both scrolls need to be cut and the number of work steps increases. The sum of the thinning amounts of both the revolving and fixed scrolls is set to an amount corresponding to δri or δsi (i = 1, 2, 3).
[0044]
Further, the technique of reducing the wrap thickness as compared with other portions, which is one embodiment of the invention described above, is performed over the entire height direction of the wrap at the portion where the wrap thickness is reduced. In the above-described embodiment, the thickness reduction may be changed, or Δr1 = Δr2 = Δr3.
[0045]
Next, the operation of the compressor shown in FIGS. 1 to 5 will be described. When the rotational power is transmitted to the pulley 21, the drive shaft 4 rotates, and the auxiliary drive shaft 5 rotates in synchronization with the drive shaft 4 by the timing belt 7. Then, the orbiting scroll 3 simultaneously produces a orbiting motion having the radius of the eccentricity ε of the drive shaft 4 and the auxiliary drive shaft 5. As a result, the gas is sucked from the suction ports 22 and 23 and enters the suction chamber 16. Thereafter, the gas further flows into the compression working chamber 14 above the orbiting scroll head plate 3a and the compression working chamber 15 below the orbiting scroll head plate 3a, and is compressed to a predetermined pressure toward the center of the spiral. The gas compressed in the compression working chamber 15 finally flows into the discharge space at the center of the upper compression working chamber 14 through the discharge communication hole 8 provided at the center of the end plate 3a, and the gas flows upward. The gas merges with the gas compressed in the compression working chamber 14 and flows out of the machine from a discharge port 9 provided in the fixed scroll 1.
[0046]
During the compression operation, the compression working chambers 14 and 15 maintain the balance of the gas pressure in the compression working chambers above and below the end plate by the communication holes 3f, so that the total sum of the thrust forces of the compressed gas becomes substantially equal. For this reason, the orbiting scroll is not strongly pressed against any fixed scroll, and a large thrust load does not act on the leading end surface of the wrap. Therefore, the sliding loss at the wrap tip can be kept to a minimum. Furthermore, since there is almost no lubricating oil in the compression working chambers 14 and 15, the generation of compression heat becomes active, but this heat is generated by forced air cooling around the radiation fins provided on the outer surface of the fixed scroll as a duct structure. Effectively removed. Therefore, the orbiting scroll and the fixed scroll are kept at an appropriate temperature.
[0047]
Although FIG. 1 shows that the discharge port is provided only in the fixed scroll 1, the discharge port can be provided in the center of the fixed scroll 2 (a position where the discharge port position of the fixed scroll 1 is inverted). The heat generated by the compression can keep the entire temperature of the scroll member low by forcibly cooling the heat radiation fins of the fixed scrolls 1 and 2 and the inside of the end plate 3a of the orbiting scroll and the outer periphery of the orbiting scroll. Further, since the portion of the scroll wrap near the suction port is thinned in advance, even if the thermal expansion of the scroll wrap becomes non-uniform, it is possible to preferably prevent the contact on the side of the wrap.
[0051]
In the scroll compressor for an air conditioner, as in the case of the above-described air compressor, the suction gas flows directly into the compression working chamber, so that the amount of thermal deformation on the side surface of the wrap is greatly affected by the cold suction gas.
[0052]
A brief description will be given. Since the air conditioner is operated throughout the year, a cooling operation, a heating operation, or a defrosting operation is performed, and the temperature conditions are variously changed. Generally, when the heating operation is performed in a low temperature state where the outside air temperature is equal to or lower than zero degree, the suction temperature may be extremely low, for example, about -15 ° C. On the other hand, the average temperature is about 18 ° C. in the cooling operation, and in the defrosting operation, the expansion valve is opened and the indoor fan is not operated.
[0053]
Therefore, the maximum fluctuation range of the compressor suction temperature that can be considered throughout the year is very large, about 50 deg, so even if the orbiting scroll and the fixed scroll are made of the same material, the difference in the amount of thermal deformation near the suction port will also increase. Conceivable. Furthermore, when the fixed scroll is made of an iron-based metal and the orbiting scroll is made of an aluminum alloy, there is a possibility that the difference in the amount of thermal deformation becomes larger.
[0054]
As described above, the difference in thermal expansion between the turning and fixed scrolls in the scroll compressor having the above-described configuration affects the change in the radial gap at the seal point, resulting in a change in performance, and cannot be ignored.
[0059]
Considering all the operating conditions throughout the year, such as cooling operation and heating operation, the amount of shift of the lap side curve is, as described above, the maximum fluctuation width of the compressor suction temperature is very large, about 50 deg. It is considered that even if the scroll and the fixed scroll are made of the same material, the difference in the amount of thermal deformation in the vicinity of the inlet increases. If the suction temperature is different by 50 degrees, the difference in the amount of deformation becomes very large. In this embodiment, in consideration of these, the escape is provided on the side surface of the wrap so as to prevent the contact in advance, so that it is possible to prevent the generation of abnormal noise due to the contact of the wrap over the years.
[0060]
Furthermore, since the radial gap is provided in advance from the time of assembly, the processing tolerance of the scroll wrap, the center error of the bearing, the bearing gap, and the misalignment at the time of assembly, etc. It also has the effect of reducing the chance of contact.
[0061]
Although the present embodiment has been described as providing a compressor, the present invention can be applied to other uses, for example, a vacuum pump, and can also be used for a compressor for compressing various gases.
[0062]
【The invention's effect】
According to the present invention,In the double-toothed scroll fluid machine, when the scroll fluid machine is assembled by making the thickness of the scroll wrap portion other than the winding start portion and the winding end portion of each scroll wrap or the portion adjacent to the suction port substantially equal to each other, at least The two scrolls formed inside the fixed scroll wrap by meshing with the orbiting scroll wrap at a position (portion P) of the fixed scroll wrap where the suctioned gas sucked from the suction port comes in direct contact with the end of the orbiting scroll wrap. Since the minimum radial gap between the wraps is formed larger than the minimum radial gap in the other scroll wrap part, the minimum radial gap in the P portion of the fixed scroll wrap is formed.Absorbs the difference in the amount of thermal expansion between the orbiting scroll and the fixed scrollBecause you canWhile preventing the performance of the compressor from being degraded, it is possible to prevent the wrap contact due to the thermal deformation of the scroll member caused by the compression heat during the operation of the compressor.
[Brief description of the drawings]
FIG. 1 is an overall sectional view of an outer peripheral drive type scroll compressor showing an embodiment of the present invention.
FIG. 2 is a side view of an outer peripheral drive type scroll compressor to which the present invention is applied.
FIG. 3 is a plan view showing a state in which a wrap portion of a fixed scroll is engaged with the orbiting scroll in one embodiment of the present invention.
FIG. 4 is a plan view of a fixed scroll showing one embodiment of the present invention.
FIG. 5 is a plan view of an orbiting scroll showing one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fixed scroll, 2 ... Fixed scroll, 3 ... Orbiting scroll, 4 ... Main drive shaft, 5 ... Auxiliary drive shaft, 6 ... Cover, 7 ... Timing belt, 8 ... Discharge communication hole, 9 ... Discharge port, 10, 11 , 12 ... rolling bearing, 13 ... elastic support member, 14, 15 ... compression working chamber, 17, 18 ... balance weight, 19 ... positioning means, 20 ... toothed pulley, 21 ... pulley, 22, 23 ... suction port, 24 , 25 ... dust lap, 26 ... head cooling hole.51 ...Main bearing mounting part, 52 ...Secondary bearing mounting part.

Claims (5)

A pair of fixed scrolls in which spiral scroll wrap surfaces are arranged in parallel with each other facing each other, and spiral scroll wraps provided between these two fixed scrolls and provided on both sides of the end plate are respectively provided on the fixed scroll wraps. In a double-toothed scroll fluid machine including an orbiting scroll formed so as to mesh with, and a suction port provided on the fixed scroll side of an outer peripheral portion of the scroll wrap,
  The thickness of the other scroll wrap portion except for the winding start portion and the winding end portion or the portion adjacent to the suction port of each scroll wrap is substantially equal,
  When the scroll fluid machine is assembled, the orbiting scroll wrap is provided inside the fixed scroll wrap at a position (part P) at which the at least the suction gas sucked from the suction port comes in direct contact with the end of the orbiting scroll wrap winding end. The minimum radial gap between both scroll wraps formed by meshing with the scroll wrap is formed larger than the minimum radial gap in the other scroll wrap portion.
  A scroll fluid machine characterized by the above-mentioned. 2. The inner curve (2bi) of the fixed scroll wrap at a position (part P) off the end of the orbiting scroll wrap winding of the fixed scroll wrap in direct contact with the suction gas sucked from the suction port according to claim 1, A scroll fluid machine wherein a minimum radial gap between wraps is formed in a concave curve so as to form a concave curve. 3. The outer curve of the orbiting scroll wrap (part B) corresponding to a position (part P) of the fixed scroll wrap that comes into direct contact with the suctioned gas sucked from the suction port from the end of the orbiting scroll wrap winding. A scroll fluid machine wherein (3bo) is moved inward to reduce the wrap thickness of the portion, thereby increasing the minimum radial gap between the wraps of the portion. The minimum radial distance between the wraps of the fixed scroll wrap according to any one of claims 1 to 3, wherein the fixed scroll wrap inner curve (2bi) at the winding end portion (Q portion) of the fixed scroll wrap is formed as a curve depressed outward. A scroll fluid machine having a large gap. 5. The wrap of the fixed scroll wrap according to claim 1, wherein the outer scroll wrap (3 bo) corresponding to the winding end portion (Q portion) of the fixed scroll wrap is formed as a curve moved inward. A scroll fluid machine characterized by having a large minimum radial gap between them.

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