JP2011106353A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the size of a gap between lap contacts varies from place to place during operation, resulting in insufficient inhibition of the leakage of a refrigerant through the diametrical gap of the lap side face. <P>SOLUTION: The compression chamber is constructed either so that the inner wall side of a swirl scroll lap 13a and the outer wall side of a fixed scroll lap 12a contact with each other or so that the outer wall side of the swirl scroll lap 13a and the inner wall side of the fixed scroll lap 12a contact with each other, and the roughness of the wall surface of the swirl scroll lap 13a or the fixed scroll lap 12a on the side on which the laps do not contact with each other is increased as compared to the roughness of the wall surface of the swirl scroll lap 13a or the fixed scroll lap 12a on the side on which the laps contact with each other, whereby the refrigerant is prevented from leaking through the diametrical gap on the wall surface on the side on which the laps contact with each other, and the refrigerant is prevented from leaking on the wall surface on the side on which the laps do not contact with each other by increasing the resistance of the path by increasing the surface roughness. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a scroll compressor used in a cooling device such as a cooling / heating air conditioner or a refrigerator, or a heat pump type hot water supply device.

  Conventionally, scroll compressors used in refrigeration air conditioners and refrigerators generally engage a fixed scroll and a rotating scroll in which a spiral wrap rises from an end plate to form a compression chamber therebetween, and the rotating scroll is rotated by a rotation restraint mechanism. When it is swung along a circular orbit under the constraint of the above, suction, compression, and discharge are performed by moving the compression chamber while changing the volume. Here, FIG. 9 shows a refrigerant leakage path during compression of the conventional scroll compressor. Regarding the scroll compressor, there are mainly 2 refrigerant leakages in the axial gap at the lap tip shown in FIG. 9A and refrigerant leakage in the radial gap in the wrap side surface (wall surface) shown in FIG. There are two leak paths. The prior art for preventing refrigerant leakage in each gap will be described.

  First, a technique for suppressing refrigerant leakage in the axial gap at the wrap tip will be described. The working fluid is gradually compressed along with the orbiting motion of the orbiting scroll 13 and becomes a high pressure state toward the center portion. Therefore, a separating force acts on the orbiting scroll 13 in a direction away from the fixed scroll 12. As a result, a gap is generated at the end of the wrap between the orbiting scroll 13 and the fixed scroll 12, so that leakage occurs during compression, resulting in performance deterioration. As a countermeasure, there is a method of preventing separation from the fixed scroll 12 by applying high and low intermediate pressures to a back pressure chamber 29 provided on the back surface of the orbiting scroll 13 (see, for example, Patent Document 1).

  FIG. 10 is a cross-sectional view of a compression mechanism portion of a conventional scroll compressor described in Patent Document 1. In addition, about the code | symbol in a figure, it demonstrates using what is shown by patent document 1. FIG. The orbiting scroll 3 is provided with a communication passage 22 provided on the end plate 3b of the orbiting scroll 3 and communicating with the back pressure chamber side opening end 22b that opens to the back pressure chamber from the compression chamber side opening end 22c that opens to the compression chamber side. With the movement, the communication passage 22 is connected and closed by opening and closing the compression chamber side opening end 22c by the end plate 2b of the fixed scroll 2. By this communication and closing operation, the pressure in the back pressure chamber is maintained at a predetermined pressure (= intermediate pressure). As a result, the orbiting scroll 3 is appropriately pressed against the fixed scroll 2 so that the axial gap at the tip of the wrap is kept to a minimum, so that refrigerant leakage can be prevented.

  Further, the compression chamber side opening end 22 c is formed outside the orbiting scroll 3 by periodically moving in the compression chamber communicating with the thrust surface of the fixed scroll 2 and the suction chamber as the orbiting scroll 3 rotates. Oil is intermittently supplied to the compression chamber, and the supplied oil acts as a seal for this compression chamber, and refrigerant leakage is suppressed in the radial gap as well as in the axial gap of the working fluid, reducing the compression efficiency Is suppressed.

  Next, a refrigerant leakage suppression technique in the radial gap on the side surface of the wrap will be described. 11 and 12 are cross-sectional views of a compression mechanism portion of a conventional scroll compressor described in Patent Document 2. FIG. In addition, about the code | symbol in a figure, it demonstrates using what is shown by patent document 2. FIG. An eccentric portion 2 a is provided at the upper end portion of the crankshaft 2. A slide bush 201 with a balance weight 201c is loosely fitted to the eccentric part 2a so as to have a gap with the eccentric part 2a. The slide bush 201 has a cylindrical portion 201a that can be loosely fitted to the eccentric portion 2a, and a balance weight 201c attached to the outer periphery of the cylindrical portion 201a opposite to the eccentric direction of the eccentric portion 2a. The rotational force of the crankshaft 2 can be transmitted to the compression element CF through the slide bush 201.

  Here, the role of the slide bush 201 is as follows. In order to separate the refrigerant between the two compression chambers in the compression element CF so that there is no leakage of the refrigerant, the spiral tooth portions 3b and 4b of the orbiting scroll 3 and the fixed scroll 4 are spaced apart between the two compression chambers. It needs to be in contact. Since the slide bush 201 is fitted to the eccentric part 2a of the crankshaft 2 with a gap (is loosely fitted), the orbiting scroll 3 can be slid by the gas force in the compression chamber. The spiral tooth portions 3b and 4b of the orbiting scroll 3 and the fixed scroll 4 can be brought into contact with each other without any gap between the two compression chambers. That is, the slide bush 201 is loosely fitted to the eccentric portion 2 a of the crankshaft 2, thereby making it possible to slide the orbiting scroll 3 so that refrigerant does not leak between the compression chambers.

JP 2007-270697 A JP-A-4-175486

  When assembling the compression mechanism of the scroll compressor, the laps of both scroll parts have a plurality of lap contacts, and the gaps at the lap contacts are uniform or in contact. Here, the lap contact is defined as a point where the distance between the wraps is closest when the compression scroll is formed between the fixed scroll and the orbiting scroll. FIG. 3 shows the definition of the position and name of the lap contact. On the macro scale that captures the entire part as shown in FIG. 3, the laps seem to be in contact with each other at the same time. However, when considered on a microscopic scale, the member temperature of the orbiting scroll and the fixed scroll is different during operation, so it is expected that only some of the lap contacts will be in contact with each other, and there will be minute gaps for the other lap contacts. The refrigerant leaks from the gap. However, in the above prior art, there is no disclosure about such a gap between the orbiting scroll and the fixed scroll lap contact during operation, and no suggestion of a corresponding technology or the like.

  In the above related art relating to refrigerant leakage suppression in the axial gap at the lap tip, the axial gap at the lap tip can be minimized by appropriately pressing the orbiting scroll in the axial direction of the fixed scroll. There is no disclosure of a technique related to enhancing the sealing effect in the radial gap on the side surface of the lap while focusing on the gap of the lap contact.

  Further, in the above related art relating to refrigerant leakage suppression in the radial gap on the side surface of the lap, when trying to make the orbiting scroll lap contact the fixed scroll lap, only a part of the lap contact contacts during operation. Nothing is disclosed. During actual operation, it is difficult to bring all the lap contacts into contact at the same time, leading to an increase in leakage loss due to refrigerant leakage. Further, since it is necessary to configure the bearing diameter to be large so that the slide bush can be inserted into the bearing, an increase in sliding loss at the bearing portion and an increase in cost due to an increase in the number of parts have been caused.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a highly efficient scroll compressor by effectively preventing refrigerant leakage during compression in consideration of a gap between lap contacts during operation.

In order to solve the conventional problems, the scroll compressor according to the present invention is configured such that the inner wall side of the orbiting scroll wrap and the outer wall side of the fixed scroll wrap contact each other, or the outer wall side of the orbiting scroll wrap and the fixed scroll wrap The compression chamber is configured to be in contact with the inner wall side, and at least the surface of the orbiting scroll wrap on the side that contacts the roughness of the wall surface of the orbiting scroll wrap on the side where the wraps do not contact each other. Increase the surface roughness of the fixed scroll wrap on the side where the wraps do not contact each other, or increase the surface roughness of the fixed scroll wrap on the side where the wrap does not contact. It is composed. Thus, on the wall surface on the side where the wraps are in contact with each other, the refrigerant leakage is prevented by reducing the radial gap, and on the wall surface on the side where the wraps are not in contact, the passage resistance is increased by making the surface roughness larger than that on the side where the laps are in contact. Since the refrigerant can be prevented from leaking, a highly efficient scroll compressor can be provided.

  The scroll compressor of this invention can implement | achieve high efficiency by comprising appropriately the surface roughness of a wall surface by the way of contact with a turning scroll wrap and a fixed scroll wrap.

The longitudinal cross-sectional view of the scroll compressor in embodiment of this invention Sectional drawing of the compression mechanism part of the scroll compressor in embodiment of this invention The figure which shows the position and name of a lap contact in embodiment of this invention Characteristic diagram of gap change of lap contact considering temperature during operation in the embodiment of the present invention Characteristic diagram of gap change of lap contact in consideration of temperature and basic circle radius difference during operation in the embodiment of the present invention Characteristic diagram of gap change of lap contact considering temperature and coefficient of thermal expansion during operation in the embodiment of the present invention Moody diagram and characteristic diagram of experimental results in the embodiment of the present invention Sectional drawing which shows the change of the state which meshed and fixed the fixed scroll and the turning scroll of the scroll compressor in embodiment of this invention (A) Schematic diagram of refrigerant leakage path at axial gap at lap tip of scroll compressor (b) Schematic diagram of refrigerant leakage path at radial gap at lap side of scroll compressor Sectional drawing of the compression mechanism part of the conventional scroll compressor in patent document 1 Sectional drawing of the compression mechanism part of the conventional scroll compressor in patent document 2 AA sectional view of FIG.

  According to a first aspect of the present invention, a compression scroll is formed between the fixed scroll and the orbiting scroll, each of which has a spiral wrap rising from an end plate, and the orbiting scroll follows a circular orbit by regulation by a rotation restraint mechanism. In a scroll compressor that performs a series of operations of suction, compression, and discharge of the working fluid by moving the compression chamber toward the center while changing the volume when swung at a predetermined turning radius, The inner wall side and the outer wall side of the fixed scroll wrap are in contact with each other, or the outer wall side of the orbiting scroll wrap is in contact with the inner wall side of the fixed scroll wrap, and at least the wraps are in contact with each other. Make the wall surface of the orbiting scroll wrap on the non-contact side larger than the wall surface of the orbiting scroll wrap on the contacting side. Or one in which wraps is configured to larger than the roughness of the wall surface of the fixed scroll wrap on the side in contact with the roughness of the wall surface of the fixed scroll wrap on the side not in contact. Accordingly, the wall surface on the side where the wraps are in contact prevents the refrigerant leakage in the radial gap by appropriately reducing the surface roughness, and the wall surface on the side where the wraps are not in contact with the surface roughness is less than the side on which the surface is in contact. Since the passage resistance can be increased and the refrigerant leakage can be prevented by increasing the size, a highly efficient scroll compressor can be provided.

  In the second invention, in particular, the lap is constituted by an involute curve according to the first invention, and the basic circle radius of the involute curve of the orbiting scroll wrap is different from the basic circle radius of the involute curve of the fixed scroll wrap. When the base circle radius of the orbiting scroll wrap is larger than the base circle radius of the fixed scroll wrap, the sides where the wraps come into contact can be the outer wall side of the orbiting scroll wrap and the inner wall side of the fixed scroll wrap. . In addition, when the base circle radius of the orbiting scroll wrap is made smaller than the base circle radius of the fixed scroll wrap, the sides where the wraps come into contact can be the inner wall side of the orbiting scroll wrap and the outer wall side of the fixed scroll wrap. . Thereby, the wall surface on the side where the laps come into contact can be selectively controlled.

  The third invention is to make the coefficient of thermal expansion of the materials forming the orbiting scroll and the fixed scroll different from those of the first or second invention. If the material forming the scroll is made of, for example, an iron-based metal, the aluminum-based metal has a higher thermal expansion coefficient than the iron-based metal, so the side where the laps come into contact with the outer wall side of the orbiting scroll and the fixed scroll wrap Can be on the inner wall side. Further, when the material forming the orbiting scroll is made of, for example, an iron-based metal, and the material forming the fixed scroll is made of, for example, an aluminum-based metal, the side where the wraps contact each other is the inner wall side of the orbiting scroll and the outer wall side of the fixed scroll wrap. Can be. This makes it possible to selectively control the wall surface on the side where the lap contacts.

  The fourth aspect of the invention relates to the amount of oil supplied to the compression chamber formed on the side where the wrap is in contact with the amount of oil supplied to the compression chamber formed on the side where the lap does not contact, By increasing the amount, the sealing effect can be enhanced and refrigerant leakage can be prevented more effectively.

  In the fifth aspect of the invention, in particular, by using carbon dioxide as the working fluid of any one of the first to fifth aspects of the invention, refrigerant leakage can be more effectively prevented even when the differential pressure during compression is large. Can do.

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

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a scroll compressor according to an embodiment of the present invention, and FIG. 2 is a sectional view of a compression mechanism portion of FIG. Hereinafter, operation | movement and an effect | action are demonstrated about a scroll compressor.

  As shown in FIGS. 1 and 2, the scroll compressor of the present invention includes a main bearing member 11 of a crankshaft 4 fixed by welding or shrink fitting in a sealed container 1, and a bolt on the main bearing member 11. The scroll-type compression mechanism 2 is configured by sandwiching the orbiting scroll 13 meshing with the fixed scroll 12 between the fixed scroll 12 and the rotation of the orbiting scroll 13 between the orbiting scroll 13 and the main bearing member 11. Then, a rotation restraint mechanism 14 such as an Oldham ring that guides the circular scroll to move is provided, and the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4 a at the upper end of the crankshaft 4, whereby the orbiting scroll 13 is circularly orbited. As a result, the compression chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 moves from the outer peripheral side to the center portion. Utilizing this, the refrigerant gas is sucked and compressed from the suction pipe 16 leading to the outside of the sealed container 1 and the suction chamber 17 on the outer peripheral portion of the fixed scroll 12, and the refrigerant gas having a predetermined pressure or higher is compressed. The reed valve 19 is pushed open from the discharge port 18 at the center of the fixed scroll 12 and discharged into the sealed container 1 repeatedly.

A high pressure region 30 and a back pressure chamber 29 set to a high pressure and a low pressure are formed on the back surface 13e of the orbiting scroll 13. By applying pressure on the back surface 13e, the orbiting scroll 13 is stably pressed against the fixed scroll 12, and leakage can be reduced and the circular orbit motion can be stably performed.

  During operation of the compressor, a pump 25 is provided at the lower end of the crankshaft 4 and is driven simultaneously with the scroll compressor. As a result, the pump 25 sucks up the oil 6 in the oil reservoir 20 provided at the bottom of the hermetic container 1 and removes foreign matter with an oil filter or the like, and then passes through the oil supply hole 26 running vertically through the crankshaft 4. Supply to the compression mechanism 2. The supply pressure at this time is substantially equal to the discharge pressure of the scroll compressor, and also serves as a back pressure source for the orbiting scroll 13. As a result, the orbiting scroll 13 does not move away from the fixed scroll 12 and does not come into contact with each other, and the predetermined compression function is stably exhibited.

  Part of the oil 6 supplied in this way enters the fitting portion between the eccentric shaft portion 4a and the orbiting scroll 13 and the bearing portion 66 between the crankshaft 4 and the main bearing member 11 due to the supply pressure and its own weight. Then, the respective parts are lubricated and dropped, and the oil sump 20 is returned.

  FIG. 3 shows the definition of the position and name of the lap contact when the compression scroll 15 is formed between the fixed scroll wrap 12a and the orbiting scroll wrap 13a. In general, since the scroll compressor has two or more wraps, three or more lap contacts are present at the same time as shown in FIG. In the description of the first embodiment, according to the definition of the name shown in FIG. 3, the contact formed on the outer wall 13a1 side of the orbiting scroll wrap 13a is referred to as an outer wall contact, and the contact formed on the inner wall 13a2 side is referred to as an inner wall contact. To. Further, numbers 1, 2, and 3 are assigned from the contact points close to the center of the orbiting scroll 13.

  4 to 6 show a change in the gap at the lap contact point during operation for each rotation angle (crank angle) of the crankshaft 4. 4-6, the calculation conditions are the rated operating conditions of a heat pump water heater using a carbon dioxide refrigerant. Further, the gap change in the lap contact during operation indicates the change in the gap of the lap contact during operation when the gap of the lap contact during assembly is set as a reference (= 0). On the vertical axis, a positive value means that the gap is enlarged, and a negative value means that the gap is reduced. In the following, each figure will be considered in turn.

  FIG. 4 shows a change in the gap of the lap contact when the temperature during operation is taken into consideration. In the scroll compressor in the embodiment, the temperature of the fixed scroll 12 is higher than that of the orbiting scroll 13 because the sealed container 1 is filled with high-temperature and high-pressure discharge gas. As a result, the gap of the lap contact is reduced at the inner wall side contact (inner wall contact 2). On the other hand, it can be seen that the gap between the lap contacts increases for the outer wall side contacts.

  About FIG. 5, the temperature at the time of a driving | running | working and the clearance gap change of the lap contact when the base circle radius of the turning scroll wrap 13a is comprised 0.034% smaller than the base circle radius of the fixed scroll wrap 12a are shown. As can be seen from FIG. 5, the gap between the lap contacts on the inner wall 13a2 side can be selectively reduced by changing the base circle radius. On the contrary, if the base circle radius of the orbiting scroll wrap 13a is larger than the base circle radius of the fixed scroll wrap 12a (not shown), the gap between the lap contacts on the outer wall 13a1 side can be selectively reduced.

For FIG. 6, the temperature at the time of operation and the material for forming the orbiting scroll 13 are made of aluminum-based metal, and the material for forming the fixed scroll 12 is made of iron-based metal. It shows the gap change of the lap contact. As can be seen from FIG. 6, since the orbiting scroll 13 is more thermally expanded than the fixed scroll 12, it is possible to selectively reduce the gap between the lap contacts on the outer wall 13a1 side. On the other hand, the material for forming the orbiting scroll 13 is made of an iron-based metal and the material for forming the fixed scroll 12 is made of an aluminum-based metal (not shown), so that the gap between the lap contacts on the inner wall 13a2 side is selectively reduced. can do.

  Not only when the sealed container 1 is filled with high-temperature and high-pressure discharge gas, but also when it is filled with low-temperature and low-pressure suction gas, or when operating conditions other than the rated operating conditions or the refrigerant is changed As for the operating conditions, the gap between the outer wall 13a1 side or the inner wall 13a2 side of the orbiting scroll wrap 13a can be selectively set by adjusting the amount of change in the basic circle radius and the combination of metals having different thermal expansion coefficients. Can be small. As a result, the gap between the lap contacts comes into contact, and refrigerant leakage can be reduced.

  On the other hand, when the gap of the lap contact on the outer wall 13a1 side of the orbiting scroll wrap 13a is selectively reduced and brought into contact, the gap of the lap contact on the inner wall 13a2 side of the orbiting scroll wrap 13a on the opposite side is increased. Further, when the gap of the lap contact on the inner wall 13a2 side of the orbiting scroll wrap 13a is selectively reduced and brought into contact, the gap of the lap contact on the outer wall 13a1 side of the orbiting scroll wrap 13a on the opposite side is increased.

With these configurations, a method for preventing refrigerant leakage when the gap between the lap contacts is increased will be described. Generally, as is well known as the Darcy-Weisbach equation, the flow rate through the gap (pipe) is
△ p = λ · (L / d) · (ρ · u 2/2) ··· (1)
It is represented by Here, Δp is a differential pressure, λ is a pipe friction coefficient, L is a flow path length, d is a pipe diameter, ρ is a fluid density, and u is a fluid flow velocity.

  Next, the relationship between the pipe friction coefficient λ and the roughness will be shown. FIG. 7 shows the relative roughness obtained by dividing the Reynolds number on the horizontal axis by the pipe friction coefficient λ on the left side of the vertical axis and the average protrusion height showing the roughness on the right side of the vertical axis by the pipe diameter (Moody diagram). In FIG. 7, it is shown that the pipe friction coefficient λ increases as the roughness increases, and the flow rate through the gap (pipe) can be reduced from the equation (1).

  Next, it was verified whether the relationship shown in the Darcy-Weisbach equation shown in FIG. 7 can be applied to the radial clearance of the scroll compressor. The pipe friction coefficient λ was measured by an experimental apparatus simulating the shape of the radial gap of the scroll compressor. Here, since the radial gap of the scroll compressor is rectangular, the radial gap is replaced with a hydraulic diameter that is a hydraulically equivalent diameter. FIG. 7 simultaneously plots the pipe friction coefficient λ when the lap gap δa = 10 μm. Further, the pipe friction coefficient λ when oil was mixed was also measured at the same time. The mixing rate is 2.8%. As can be seen from these results, the Darcy-Weisbach equation can be applied to the leakage passage in the scroll compressor, and the pipe friction coefficient λ can be increased by mixing oil. all right.

  From the above results, the roughness of the wall surface of the orbiting scroll wrap 13a on the side where the wraps do not contact each other is made larger than the roughness of the wall surface of the orbiting scroll wrap 13a on the contact side, or the side where the wraps do not contact each other. By increasing the roughness of the wall surface of the scroll wrap 12a as compared with the roughness of the wall surface of the fixed scroll wrap 12a on the contact side, the passage resistance can be increased and refrigerant leakage can be prevented.

As described above, if the refrigerant leakage can be prevented by roughening the roughness, there is a minute gap caused by the processing accuracy also on the lap contact on the wall surface on the side where the lap contacts. By making the roughness rough, it is possible to prevent refrigerant leakage. However, the gap between the walls on the side where the lap contacts is small enough to prevent the refrigerant from leaking, and in addition, the loss due to frictional resistance when the lap contacts increases, resulting in a decrease in the efficiency of the entire scroll compressor. I will. From the above, the roughness of the wall surface of the orbiting scroll wrap 13a on the side where the wraps do not contact or the wall surface of the fixed scroll wrap 12a is determined on the wall surface of the orbiting scroll wrap 13a or the wall surface of the fixed scroll wrap 12a. It needs to be larger than the roughness.

  Next, paying attention to the fact that refrigerating can be further prevented by refueling with a rougher surface, the compression formed on the compression chamber 15 and the inner wall 13a2 side formed on the outer wall 13a1 side of the orbiting scroll wrap 13a. A specific configuration for selectively increasing the amount of oil supply to either one of the chambers 15 will be described.

  The orbiting scroll 13 is formed with a path 55 having one opening end 55 a in the back pressure chamber 29 and the other opening end 55 b at the lap tip 13 c of the orbiting scroll 13. FIG. 8 shows a state where the orbiting scroll 13 is engaged with the fixed scroll 12, and the phase is shifted by 90 degrees. For example, in the case of the configuration shown in FIG. 8, the other opening end 55 b of the path 55 is periodically opened in two recesses 12 d and 12 e formed in the wrap bottom surface 12 c of the fixed scroll 12, thereby The intermittent communication of the route is realized.

  In the state of FIG. 8B, the open end 55b opens into the recess 12d, and in this state, the outer compression chamber 15a formed outside the orbiting scroll wrap 13a and the back pressure chamber 29 communicate with each other. And the oil is supplied from the back pressure chamber 29 to the outer compression chamber 15a through the first route. In the state of (d), the opening end 55b opens to the recess 12e. In this state, the second path through which the inner compression chamber 15b and the back pressure chamber 29 formed inside the orbiting scroll wrap 13a communicate with each other is provided. Oil is supplied from the back pressure chamber 29 to the inner compression chamber 15b through the second path. On the other hand, in (a) and (c), since the opening end 55b does not open to the two recesses 12d and 12e, oil is not supplied from the back pressure chamber 29 to the compression chamber.

  From the above, the oil 6 in the back pressure chamber 29 is guided to the compression chamber 15 through the first and second paths, and leakage during compression can be prevented. Here, by adjusting the size and position of the opening end 55b and the size and position of the two recesses 12d and 12e, it is possible to adjust the ratio at which the first path communicates and the ratio at which the second path communicates. It becomes possible. That is, it becomes possible to increase the amount of oil supplied to either the outer compression chamber 15a formed outside the orbiting scroll wrap 13a or the inner compression chamber 15b formed inside the orbiting scroll wrap 13a.

  Finally, when the working fluid is a high-pressure refrigerant, such as carbon dioxide, refrigerant leakage can be more effectively prevented even when the differential pressure during compression is large.

  As described above, in the scroll compressor according to the present invention, the roughness of the wall surface of the orbiting scroll on the side where the lap does not contact or the wall surface of the fixed scroll is determined. This is larger than the roughness of. As a result, refrigerant leakage is prevented by reducing the radial clearance on the wall surface on the side where the lap contacts, and on the wall surface on the side where the lap does not contact, the passage resistance is increased by increasing the surface roughness, thereby causing refrigerant leakage. Therefore, a highly efficient scroll compressor can be provided. Therefore, the working fluid is not limited to a refrigerant, and can also be applied to a scroll fluid machine including a scroll compressor using an air or helium working fluid or an expander.

DESCRIPTION OF SYMBOLS 12 Fixed scroll 12a Fixed scroll wrap 12c Lap groove bottom surface 12d Concave 12e Concave 13 Orbiting scroll 13a Orbiting scroll wrap 13c Lap tip 13e Back surface 14 Rotation restraint mechanism 15 Compression chamber 15a Orbiting scroll wrap outer compression chamber 15b Orbiting scroll lap inner compression chamber 29 Back pressure chamber 30 High pressure region 54 Fourth path 54a Open end (high pressure region side)
54b Open end (back pressure chamber side)
55 1st and 2nd path | routes 55a Open end (back pressure chamber side)
55b Open end (compression chamber side)
56 3rd path | route 56a Open end (high pressure area | region side)
56b Open end (suction chamber side)
56c Restriction part (by cross-sectional area reduction)
56d Aperture (due to gap)

Claims (5)

A compression chamber is formed by engaging the fixed scroll and the orbiting scroll with which the spiral wrap rises from the end plate, and the orbiting scroll has a predetermined orbiting radius along a circular orbit by regulation by a rotation restraint mechanism. In a scroll compressor that performs a series of operations of suction, compression, and discharge of the working fluid by moving the compression chamber toward the center while changing the volume when swung, it is fixed to the inner wall side of the orbiting scroll wrap. The outer wall side of the scroll wrap is in contact with the outer wall side of the orbiting scroll wrap and the inner wall side of the fixed scroll wrap is in contact with each other, and at least the wraps do not contact each other. The wall surface roughness of the orbiting scroll wrap on the side is compared with the wall surface roughness of the orbiting scroll wrap on the side Or the roughness of the wall surface of the fixed scroll wrap on the side where the wraps do not contact each other is made larger than the roughness of the wall surface of the fixed scroll wrap on the contact side. Scroll compressor. The lap is configured by an involute curve, and a base circle radius of the involute curve of the wrap of the orbiting scroll is different from a base circle radius of the involute curve of the wrap of the fixed scroll. Scroll compressor. The scroll compressor according to claim 1 or 2, wherein the orbiting scroll and the material forming the fixed scroll have different coefficients of thermal expansion. The amount of oil supplied to the compression chamber formed on the side where the wrap does not contact is increased with respect to the amount of oil supplied to the compression chamber formed on the side where the lap contacts. 4. The scroll compressor according to claim 1. The scroll compressor according to any one of claims 1 to 4, wherein the working fluid is carbon dioxide.