JP2012036825A - Scroll compressor - Google Patents

Abstract

An object of the present invention is to provide a scroll compressor that can suppress a decrease in compression efficiency by reducing leakage loss without improving the contour accuracy of a lap.
At least one of the first wrap 24b of the fixed scroll and the second wrap 26b of the orbiting scroll has a shape such that the clearance on the inner side in the lap radial direction is narrower than the clearance on the outer side in the wrap radial direction. is doing. The clearance is a radial gap between the first wrap 24b and the second wrap 26b when the side surface of the first wrap 24b and the side surface of the second wrap 26b are closest to each other.
[Selection] Figure 4A

Description

  The present invention relates to a scroll compressor.

  In the scroll compressor, the fixed scroll wrap and the orbiting scroll wrap mesh with each other to form a plurality of compression chambers. Then, as the orbiting scroll revolves with respect to the fixed scroll, the compression chamber decreases in volume while moving from the radially outer side of the wrap toward the radially inner side. Thereby, the refrigerant gas in the compression chamber is compressed.

  Also, in the scroll compressor, a clearance, which is a minute gap in the radial direction of the wrap, is provided between both wraps so that the fixed scroll lap and the orbiting scroll wrap do not contact each other during the revolution of the orbiting scroll. ing. For example, in the scroll compressor disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 11-159481), the outer periphery of the wrap is secured so that clearance is ensured even when the lap is thermally deformed during operation of the compressor. A part of the surface and the inner peripheral surface are formed thinner than the other parts.

  However, in the conventional scroll compressor, the winding end portion, which is the outer portion in the radial direction of the wrap, has a larger radius of curvature than the winding start portion, which is the inner portion in the radial direction of the wrap. It is difficult to improve contour accuracy. Therefore, compared to the winding start portion, the tooth thickness after processing tends to be larger than the value based on the theoretical shape at the winding end portion. As a result, the clearance at the winding start portion becomes larger than the clearance at the winding end portion, and the wrapping of the orbiting scroll and the wrapping of the fixed scroll are performed before the winding start portion during the operation of the scroll compressor. In some cases, they may come into contact with each other.

  Furthermore, in the conventional scroll compressor, the pressure difference between the adjacent compression chambers is larger in the compression chamber located on the radially inner side of the wrap than on the compression chamber located on the radially outer side of the wrap. Therefore, in the compression chamber on the radially inner side of the wrap, the refrigerant gas tends to flow into the adjacent compression chamber via the clearance, and the refrigerant gas is compressed in the compression chamber. In the process, leakage loss may occur.

  An object of the present invention is to provide a scroll compressor with little leakage loss without improving the wrap contour accuracy.

  A scroll compressor according to a first aspect of the present invention includes a fixed scroll and a turning scroll. The fixed scroll has a first end plate and a first wrap. The first wrap is erected while maintaining a spiral shape on one surface of the first end plate. The orbiting scroll has a second end plate and a second wrap. The second wrap is erected while maintaining a spiral shape on one surface of the second end plate. The orbiting scroll revolves with respect to the fixed scroll while the second lap meshes with the first wrap. At least one of the first wrap and the second wrap has a shape such that the clearance is smaller at the second point inside the wrap radial direction than at the first point outside the wrap radial direction. The clearance is a radial gap between the first lap and the second lap when the side surface of the first lap and the side surface of the second lap are closest to each other.

  In the scroll compressor according to the first aspect, the fixed scroll and the orbiting scroll form a plurality of compression chambers when the first wrap and the second wrap mesh with each other. The low-pressure refrigerant gas before being compressed is sucked into a compression chamber formed at the outermost side in the lap radial direction. The compression chamber reduces its volume while moving inward in the lap radial direction by the revolution of the orbiting scroll. At this time, the low-pressure refrigerant gas in the compression chamber is compressed into a high-pressure refrigerant gas. The compressed high-pressure refrigerant gas is discharged from the compression chamber that has moved to the innermost side in the lap radial direction. Further, during the operation of the scroll compressor, each compression chamber communicates with the adjacent compression chamber via a lap through a clearance. Therefore, the compressed refrigerant gas in the compression chamber leaks into the adjacent compression chamber under a lower pressure via the clearance. As a result, there is a possibility that leakage loss, which is power loss due to the compressed refrigerant gas leaking out, is generated again.

  In the scroll compressor according to the first aspect, at least one of the first wrap and the second wrap has a shape such that the clearance on the inner side in the wrap radial direction is smaller than the clearance on the outer side in the wrap radial direction. As a result, the scroll compressor can be operated without improving the contour accuracy of the wrap in order to maintain a constant clearance from the winding end portion that is the outer portion in the wrap radial direction to the winding end portion that is the inner portion in the wrap radial direction. It is possible to reduce the leakage loss of the compression chamber on the inner side in the wrap radial direction. And the fall of compression efficiency can be suppressed by reducing the leakage loss of the compression chamber in the lap radial direction inside.

  Therefore, in the scroll compressor according to the first aspect, it is possible to suppress a decrease in compression efficiency by reducing leakage loss without improving the wrap contour accuracy.

  The scroll compressor which concerns on the 2nd viewpoint of this invention is the scroll compressor which concerns on a 1st viewpoint. WHEREIN: A 1st wrap and a 2nd wrap are the winding end point which is an edge part of a wrap radial direction outer side, and a wrap radial direction inner side And a winding start point which is an end of the. At least one of the first wrap and the second wrap has a gap decreasing region having a shape such that the clearance continuously decreases from the winding end point side to the winding start point side.

  In the scroll compressor according to the second aspect, at least one of the first wrap and the second wrap has a shape in which the clearance gradually decreases from the winding end point side to the winding start point side in the gap reduction region. Have.

  In the scroll compressor according to the third aspect of the present invention, in the scroll compressor according to the second aspect, the gap reduction region extends from the winding end point to the winding start point.

  In the scroll compressor according to the fourth aspect of the present invention, in the scroll compressor according to the second aspect, the gap reduction region extends from the winding end point to an intermediate point between the winding end point and the winding start point.

  The scroll compressor according to the fifth aspect of the present invention is the scroll compressor according to the second aspect, wherein the gap reduction region extends from the winding end point to the point of one winding from the winding end point to the winding start point. ing.

  A scroll compressor according to a sixth aspect of the present invention is the scroll compressor according to the second aspect, wherein at least one of the first wrap and the second wrap has a plurality of gap reduction regions.

  A scroll compressor according to a seventh aspect of the present invention is the scroll compressor according to the sixth aspect, wherein the gap reduction region is located at a constant interval in the circumferential direction of the wrap, and the clearance at both ends thereof is It has a shape in which the magnitude of the difference becomes a constant value.

  In the scroll compressor according to the seventh aspect, the clearance regularly changes along the wrap circumferential direction. For example, if the length of the gap reduction region in the wrap circumferential direction is set to a minute value compared to the overall length of the wrap in the wrap circumferential direction, the clearance is generally stepped from the winding end point side to the winding start point side. A wrap having a shape that changes to

  A scroll compressor according to an eighth aspect of the present invention is the scroll compressor according to any one of the first aspect to the seventh aspect, wherein at least one of the first wrap and the second wrap has a clearance at a winding end point. The difference between the winding start point and the clearance is equal to the arithmetic average of the contour level of the fixed scroll and the contour level of the orbiting scroll.

  In the scroll compressor according to the eighth aspect, the magnitude of the difference between the clearance at the winding end point and the clearance at the winding start point is calculated based on the contours of the fixed scroll and the orbiting scroll. Here, the degree of contour is an amount representing the magnitude of deviation of the actual shape of the fixed scroll 24 and the orbiting scroll 26 when the ideal shape of the fixed scroll 24 and the orbiting scroll 26 is used as a reference.

  The scroll compressor which concerns on this invention can suppress the fall of compression efficiency by reducing leakage loss, without improving the outline precision of a lap | wrap.

It is a longitudinal cross-sectional view of the scroll compressor in embodiment of this invention. It is a top view of the 1st lap of a fixed scroll in an embodiment of the present invention. It is a top view of the 2nd lap of a turning scroll in the embodiment of the present invention. It is a figure showing the positional relationship and clearance of a 1st lap and a 2nd lap in case the crank angle is 0 degree | times in embodiment of this invention. It is a figure showing the positional relationship and clearance of a 1st lap and a 2nd lap in case the crank angle is 90 degree | times in embodiment of this invention. It is a figure showing the positional relationship and clearance of a 1st lap and a 2nd lap in case the crank angle is 180 degree | times in embodiment of this invention. It is a figure showing the positional relationship and clearance of a 1st lap and a 2nd lap in case the crank angle is 360 degree | times in embodiment of this invention. It is a graph showing the relationship between clearance and a crank angle in embodiment of this invention. It is a graph showing the relationship between clearance and a crank angle in the modification 1A of embodiment of this invention. It is a graph showing the relationship between clearance and a crank angle in Modification 1C of the embodiment of the present invention. It is a graph showing the relationship between clearance and a crank angle in the conventional scroll compressor.

  A scroll compressor 101 according to an embodiment of the present invention will be described with reference to FIGS.

  First, the configuration and operation of the scroll compressor 101 common to the conventional scroll compressor will be described. Next, a configuration, operation, characteristics, and modification specific to the scroll compressor 101 according to the present embodiment will be described.

-Matters common to conventional scroll compressors-
(1) Overall Configuration The scroll compressor 101 is a high-low pressure dome type scroll compressor that plays a role of compressing refrigerant gas in a refrigerant circuit that repeats a refrigeration cycle for circulating refrigerant. FIG. 1 is a longitudinal sectional view of a scroll compressor 101 according to the present embodiment.

  As shown in FIG. 1, the scroll compressor 101 according to this embodiment includes a casing 10, a compression mechanism 15, a housing 23, a motor 16, an oil separation plate 73, a crankshaft 17, a suction pipe 19, and a discharge pipe 20. Is done. Next, these components of the scroll compressor 101 will be described in detail.

(2) Detailed configuration (2-1) Casing The casing 10 includes a substantially cylindrical body casing part 11, and a bowl-shaped upper wall part 12 welded in an airtight manner to the upper end part of the body casing part 11, It is comprised from the lower end part of the trunk | drum casing part 11 with the bowl-shaped bottom wall part 13 welded airtightly. The casing 10 is formed of a rigid member that is unlikely to be deformed or damaged when pressure and temperature change inside and outside the casing 10. The casing 10 is installed so that the substantially cylindrical axial direction of the body casing portion 11 is along the vertical direction.

  Inside the casing 10, a compression mechanism 15, a housing 23 disposed below the compression mechanism 15, a motor 16 disposed below the housing 23, and the casing 10 are disposed so as to extend in the vertical direction. A crankshaft 17 and the like are accommodated. A suction pipe 19 and a discharge pipe 20 are welded to the wall of the casing 10 in an airtight manner.

  An oil storage portion P that is a space for storing lubricating oil is formed at the bottom of the casing 10. Lubricating oil is used to keep the lubricity of sliding parts such as the compression mechanism 15 good during the operation of the scroll compressor 101.

(2-2) Compression mechanism The compression mechanism 15 is accommodated in the casing 10, sucks and compresses low-temperature and low-pressure refrigerant gas, and discharges high-temperature and high-pressure refrigerant gas (hereinafter referred to as "compressed refrigerant"). The compression mechanism 15 includes a fixed scroll 24 and a turning scroll 26. Next, the fixed scroll 24 and the orbiting scroll 26 will be described respectively.

  The fixed scroll 24 has a first end plate 24a and a spiral (involute) first wrap 24b formed upright on the first end plate 24a. The fixed scroll 24 is formed with a main suction hole (not shown) and an auxiliary suction hole (not shown) adjacent to the main suction hole. The main suction hole communicates the suction pipe 19 and a compression chamber 40 described later. The auxiliary suction hole communicates a low-pressure space S2 described later and the compression chamber 40. A discharge hole 41 is formed in the central portion of the first end plate 24a, and an enlarged recess 42 communicating with the discharge hole 41 is formed on the upper surface of the first end plate 24a. The enlarged recess 42 is a space that is recessed in the upper surface of the first end plate 24a and extends in the horizontal direction. A lid 44 is fastened and fixed to the upper surface of the fixed scroll 24 by bolts 44 a so as to close the enlarged concave portion 42. And the muffler space 45 which consists of an expansion chamber which silences the driving | running sound of the compression mechanism 15 by covering the expansion recessed part 42 with the cover body 44 is formed. The fixed scroll 24 and the lid 44 are sealed by being brought into close contact with each other via a gasket (not shown). The fixed scroll 24 is formed with a first communication passage 46 that communicates with the muffler space 45 and opens on the lower surface of the fixed scroll 24.

  The orbiting scroll 26 has a second end plate 26a and a spiral (involute) second wrap 26b formed upright on the second end plate 26a. An upper end bearing 26c is formed at the center of the lower surface of the second end plate 26a so as to protrude downward. Oil supply pores 63 are formed in the second end plate 26a. The oil supply pore 63 communicates the outer peripheral portion of the upper surface of the second end plate 26a and the space inside the upper end bearing 26c.

  The fixed scroll 24 and the orbiting scroll 26 are spaces surrounded by the first end plate 24a, the first wrap 24b, the second end plate 26a, and the second wrap 26b when the first wrap 24b and the second wrap 26b mesh with each other. A compression chamber 40 is formed.

(2-3) Housing The housing 23 is disposed below the compression mechanism 15 and is welded to the inner wall of the casing 10 in an airtight manner on the outer peripheral surface thereof. For this reason, the inside of the casing 10 is defined by a high-pressure space S <b> 1 below the housing 23 and a low-pressure section S <b> 2 above the housing 23. The housing 23 includes a main frame recess 31 that is recessed in the upper surface of the housing 23, and an upper bearing 32 that extends downward from the lower surface of the housing 23. The upper bearing 32 is formed with an upper bearing hole 33 penetrating in the vertical direction. The housing 23 is mounted with a fixed scroll component 24 by being fixed with a bolt or the like, and sandwiches the turning scroll component 26 together with the fixed scroll component 24 via an Oldham joint 39. A second communication passage 48 is formed through the outer periphery of the housing 23 in the vertical direction. The second communication passage 48 communicates with the first communication passage 46 on the upper surface of the housing 23, and communicates with the high-pressure space S <b> 1 through the discharge port 49 on the lower surface of the housing 23.

(2-4) Motor The motor 16 is a brushless DC motor housed in the casing 10 and disposed below the housing 23. The motor 16 includes a stator 51 fixed to the inner wall of the casing 10 and a rotor 52 that is rotatably accommodated with a slight gap (air gap) provided inside the stator 51.

  The stator 51 has a coil part (not shown) around which a conducting wire is wound, and a coil end 53 formed above and below the coil part. The outer peripheral surface of the stator 51 is provided with a plurality of core cut portions (not shown) that are notched from the upper end surface to the lower end surface of the stator 51 and at predetermined intervals in the circumferential direction. . The core cut portion forms a motor cooling passage 55 extending in the vertical direction between the body casing portion 11 and the stator 51.

  The rotor 52 is connected to the crankshaft 17 passing through the center of rotation in the vertical direction. The rotor 52 is connected to the compression mechanism 15 via the crankshaft 17.

(2-5) Oil Separation Plate The oil separation plate 73 is a flat plate member accommodated in the casing 10. The oil separation plate 73 is fixed to the upper end surface of the lower bearing 60.

(2-6) Crankshaft The crankshaft 17 is accommodated in the casing 10, and the axial direction thereof is arranged along the vertical direction. As shown in FIG. 1, the crankshaft 17 is slightly eccentric with respect to the shaft center of the portion excluding the upper end portion.

  The crankshaft 17 passes through the rotation center of the rotor 52 in the vertical direction and is connected to the rotor 52. The crankshaft 17 slides with the upper end bearing 26c, the upper bearing 32, and the lower bearing 60 by the shaft rotational movement. The crankshaft 17 is connected to the orbiting scroll component 26 by fitting the upper end portion of the crankshaft 17 into the upper end bearing 26c. The crankshaft 17 rotates the shaft to drive the orbiting scroll component 26.

  The crankshaft 17 has a main oil supply passage 61 formed in the axial direction. The upper end of the main oil supply passage 61 communicates with an oil chamber 83 formed by the upper end surface of the crankshaft 17 and the lower surface of the second end plate 26a. The oil chamber 83 communicates with a sliding portion (hereinafter referred to as a “sliding portion of the compression mechanism 15”) between the fixed scroll component 24 and the orbiting scroll component 26 through an oil supply hole 63 of the second end plate 26a. Then, it finally communicates with the low-pressure space S2 through the compression chamber 40. Further, the lower end of the main oil supply passage 61 communicates with the oil reservoir P.

  The crankshaft 17 has a first sub oil supply path 61 a, a second sub oil supply path 61 b, and a third sub oil supply path 61 c that branch from the main oil supply path 61. The first sub oil supply path 61 a, the second sub oil supply path 61 b, and the third sub oil supply path 61 c are formed orthogonal to the main oil supply path 61. The first sub oil supply passage 61a opens in the outer peripheral surface of the crankshaft 17 that slides with the upper end bearing 26c. The second sub oil supply passage 61 b opens in the outer peripheral surface of the crankshaft 17 that slides with the upper bearing 32. The third sub oil supply passage 61 c opens in the outer peripheral surface of the crankshaft 17 that slides with the lower bearing 60.

(2-7) Suction Pipe The suction pipe 19 is a tubular member for introducing the refrigerant of the refrigerant circuit from the outside of the casing 10 to the compression mechanism 15. The suction pipe 19 is fitted into the upper wall portion 12 of the casing 10 in an airtight manner. The suction pipe 19 penetrates the low pressure space S <b> 2 in the vertical direction, and an inner end portion is fitted in the fixed scroll 24.

(2-8) Discharge Pipe The discharge pipe 20 is a tubular member for discharging the compressed refrigerant from the high pressure space S1 to the outside of the casing 10. The discharge pipe 20 is fitted in the body casing part 11 of the casing 10 in an airtight manner. The discharge pipe 20 has an inner end located in the high-pressure space S <b> 1 near the housing 23.

(3) Operation The operation of the scroll compressor 101 will be described. Initially, the flow of the refrigerant | coolant which circulates through the refrigerant circuit with which the scroll compressor 101 is provided is demonstrated. Next, the flow of the lubricating oil in the scroll compressor 101 will be described.

(3-1) Flow of refrigerant First, the rotor 52 is rotated by driving the motor 16. As a result, the crankshaft 17 fixed to the rotor 52 performs shaft rotation motion. The rotational movement of the crankshaft 17 is transmitted to the orbiting scroll 26 via the upper end bearing 26c. Since the shaft center of the upper end portion of the crankshaft 17 is eccentric with respect to the shaft rotation motion axis of the crankshaft 17, the orbiting scroll 26 performs a revolving motion with respect to the shaft rotation center of the crankshaft 17. The orbiting scroll 26 revolves without rotating by the Oldham joint 39.

  The low-temperature and low-pressure refrigerant gas before compression is sucked into the compression chamber 40 of the compression mechanism 15 from the suction pipe 19 via the main suction hole or from the low-pressure space S2 via the auxiliary suction hole. Due to the orbiting motion of the orbiting scroll 26, the compression chamber 40 gradually decreases in volume while moving from the outer peripheral portion of the fixed scroll 24 toward the center portion. As a result, the low-temperature and low-pressure refrigerant gas in the compression chamber 40 is compressed into a compressed refrigerant. The compressed refrigerant is discharged from the discharge hole 41 to the muffler space 45, and then introduced from the discharge port 49 to the high-pressure space S1 via the first communication passage 46 and the second communication passage 48. Thereafter, the compressed refrigerant descends the motor cooling passage 55 and reaches the space below the motor 16. Thereafter, the compressed refrigerant reverses the flow direction, and the other motor cooling passage 55 and the air gap rise. Finally, the compressed refrigerant is discharged from the discharge pipe 20 to the outside of the scroll compressor 101.

  The compressed refrigerant discharged from the scroll compressor 101 through the discharge pipe 20 is cooled and liquefied by passing through the condenser. The liquefied refrigerant becomes a low-temperature and low-pressure refrigerant by passing through the expansion section. Thereafter, the low-temperature and low-pressure refrigerant is vaporized by passing through the evaporator, and is finally introduced into the scroll compressor 101 from the suction pipe 19.

(3-2) Flow of lubricating oil First, the rotor 52 is rotated by driving the motor 16. As a result, the crankshaft 17 fixed to the rotor 52 performs shaft rotation motion. When the compression mechanism 15 is driven by the rotational movement of the crankshaft 17 and the compressed refrigerant is discharged into the high-pressure space S1, the pressure in the high-pressure space S1 rises. Further, the upper end of the main oil supply passage 61 communicates with the low pressure space S <b> 2 through the oil chamber 83 and the oil supply pores 63. Thereby, a differential pressure is generated between the upper end and the lower end of the main oil supply passage 61. As a result, the lubricating oil stored in the oil storage part P is sucked from the lower end of the main oil supply passage 61 due to the differential pressure, and rises in the main oil supply passage 61.

  The lubricating oil that has moved up to the upper end in the main oil supply passage 61 and reached the oil chamber 83 is supplied to the sliding portion of the compression mechanism 15 via the oil supply holes 63. The lubricating oil that has slid along the sliding portion of the compression mechanism 15 leaks into the low pressure space S2 and the compression chamber 40. At this time, since the lubricating oil is originally high temperature and high pressure, the refrigerant gas before compression existing in the low pressure space S2 and the compression chamber 40 is overheated. At this time, the lubricating oil is mixed into the compressed refrigerant in the compression chamber 40 in the form of oil droplets. The lubricating oil mixed in the compressed refrigerant is discharged from the compression chamber 40 to the high-pressure space S1 through the same path as the compressed refrigerant. Thereafter, the lubricating oil collides with the oil separation plate 73 after descending the motor cooling passage 55 together with the compressed refrigerant. At this time, the lubricating oil adhering to the oil separation plate 73 falls in the high-pressure space S1 and reaches the oil reservoir P.

  On the other hand, most of the lubricating oil rising in the main oil supply passage 61 is supplied to the first sub oil supply passage 61a, the second sub oil supply passage 61b, and the third sub oil supply passage 61c. The lubricating oil in the first sub oil supply passage 61a lubricates the sliding portion between the crankshaft 17 and the upper end bearing 26c. The lubricating oil in the second sub oil supply passage 61b lubricates the sliding portion between the crankshaft 17 and the upper bearing 32. The lubricating oil in the third sub oil supply passage 61 c lubricates the sliding portion between the crankshaft 17 and the lower bearing 60. The lubricating oil that has lubricated these sliding portions leaks into the high-pressure space S1, falls inside the high-pressure space S1, and reaches the oil storage portion P.

-Matters specific to this embodiment-
(1) Configuration A configuration unique to the present embodiment that the fixed scroll 24 and the orbiting scroll 26 included in the compression mechanism 15 have will be described. The fixed scroll 24 and the orbiting scroll 26 are both made of cast iron and are made of a material having substantially the same thermal expansion coefficient.

(1-1) Fixed Scroll FIG. 2 is a plan view of the first wrap 24 b of the fixed scroll 24. In FIG. 2, the region sandwiched between the first wraps 24b is the surface of the first end plate 24a. The first wrap 24b is a spiral that makes approximately three turns while increasing the radius of curvature from the first winding start point PS1 that is the radially inner end to the first winding end point PE1 that is the radially outer end. It has a shape. The spiral-shaped reference line represented by a one-dot chain line in FIG. 2 is an involute curve. An involute curve is a parametric representation in a Cartesian coordinate system,
x = a (cos θ + θ sin θ)
y = a (sin θ−θ cos θ)
It is expressed by the following formula. The first wrap 24b includes a first outer flank surface 24c1 that is a side surface that is radially outward from the reference line, and a first inner flank surface 24c2 that is a side surface radially inward from the reference line.

(1-2) Orbiting Scroll FIG. 3 is a plan view of the second lap 26 b of the orbiting scroll 26. In FIG. 3, the region sandwiched between the second wraps 26b is the surface of the second end plate 26a. The second wrap 26b makes almost two and a half turns while increasing the radius of curvature from the second winding start point PS2 which is the radially inner end to the second winding end point PE2 which is the radially outer end. It has a spiral shape. In FIG. 3, the reference line of the spiral shape represented by a one-dot chain line is an involute curve. The second wrap 26b has a second outer flank surface 26c1 that is a side surface that is radially outward from the reference line, and a second inner flank surface 26c2 that is a side surface radially inward from the reference line.

  The second wrap 26b has a thickness such that a second gap reduction region is formed from the second winding end point PE2 to the second winding start point PS2. In the second gap reduction region, the clearance continuously decreases from the second winding end point PS2 side toward the second winding start point PS2 side. The clearance is a radial gap formed between the first wrap 24b and the second wrap 26b. More specifically, the clearance is such that the first inner flank surface 24c2 of the first wrap 24b and the second outer flank surface 26c1 of the second wrap 26b are closer than the neighboring points during the revolution of the orbiting scroll 26. The gap between the first inner flank surface 24c2 and the second outer flank surface 26c1 at a point or the first outer flank surface 24c1 of the first wrap 24b and the second inner flank surface 26c2 of the second wrap 26b are in the vicinity. This is a gap between the first outer flank surface 24c1 and the second inner flank surface 26c2 at a point that is closer than this point. Hereinafter, a point where a clearance is formed during the revolution of the orbiting scroll 26 is referred to as a seal point.

  4A is a diagram illustrating a state in which the first wrap 24b of the fixed scroll 24 and the second wrap 26b of the orbiting scroll 26 are engaged with each other. In FIG. 4A, clearances C1a, C1b, and C1c are formed at the seal points S1a, S1b, and S1c between the first inner flank surface 24c2 and the second outer flank surface 26c1, respectively. In FIG. 4A, clearances C2a and C2b are formed between the first outer flank surface 24c1 and the second inner flank surface 26c2 at the seal points S2a and S2b, respectively.

  In the present embodiment, the clearance located on the radially inner side is narrower than the clearance located on the radially outer side. That is, in FIG. 4A, the clearance becomes narrower in the order of C1a, C1b, and C1c, and becomes narrower in the order of C2a and C2b. The second wrap 26b has a second gap decreasing region, that is, in this embodiment, a clearance located radially inward from the second winding end point PE2 to the second winding start point PS2 is located radially outside. It has a shape that becomes narrower than the clearance to be made.

(2) Operation A process in which the refrigerant gas is compressed by the fixed scroll 24 and the orbiting scroll 26 and a change in clearance in the compression process will be described with reference to FIGS. 4A to 4D. 4A to 4D sequentially show the process in which the orbiting scroll 26 makes one revolution. A revolution angle of the orbiting scroll 26 based on a certain state during the revolution of the orbiting scroll 26 is defined as a crank angle. Here, the crank angle in the state of FIG. 4A is provisionally defined as 0 degrees. From the state of FIG. 4A, when the orbiting scroll 26 revolves by a quarter turn, the state transitions to the state of FIG. 4B. The crank angle in the state of FIG. 4B is 90 degrees. From the state of FIG. 4B, when the orbiting scroll 26 revolves by a quarter turn, the state transitions to the state of FIG. 4C. The crank angle in the state of FIG. 4C is 180 degrees. From the state of FIG. 4C, when the orbiting scroll 26 revolves further by a quarter turn, the state transitions to the state of FIG. 4D. The crank angle in the state of FIG. 4D is 270 degrees. Then, when the orbiting scroll 26 revolves only one quarter turn from the state of FIG. 4D, the state transitions to the state of FIG. 4A. The crank angle in the state of FIG. 4A is 360 degrees. That is, during the revolution of the orbiting scroll 26, the positional relationship between the first lap 24b and the second lap 26b periodically changes with a crank angle of 360 degrees as a cycle.

(2-1) Refrigerant Compression Process The process of compressing the refrigerant gas will be described in more detail. The low-temperature and low-pressure refrigerant gas before compression is supplied to the compression chamber CS1 shown in FIG. 4A. As the orbiting scroll 26 revolves, the compression chamber CS1 gradually decreases in volume while moving radially inward as shown in FIGS. 4B, 4C, and 4D. When the crank angle reaches 360 degrees, the compression chamber CS1 becomes the compression chamber CS2 shown in FIG. 4A. As the orbiting scroll 26 revolves, the compression chamber CS2 also gradually decreases in volume while moving inward in the radial direction, as shown in FIGS. 4B, 4C, and 4D. When the crank angle reaches 720 degrees, the compression chamber CS2 becomes the compression chamber CS3 shown in FIG. 4A. From this state, when the orbiting scroll 26 further revolves half a revolution and enters the state of FIG. 4C in which the crank angle is 900 degrees, the compressed refrigerant gas in the compression chamber CS3 is discharged from the discharge hole 41 to the outside of the compression mechanism 15. Discharged. That is, in the present embodiment, the crank angle changes from 0 degrees to about 900 degrees in the process of compressing the refrigerant gas.

(2-2) Change in Clearance First, the change in the position of the seal point where the clearance is formed will be described. The radially outermost seal point S1a shown in FIG. 4A moves along the circumferential direction as shown in FIGS. 4B, 4C, and 4D by the revolution of the orbiting scroll 26. When the crank angle reaches 360 degrees, the seal point S1a becomes the seal point S1b shown in FIG. 4A. By the revolution of the orbiting scroll 26, the seal point S1b also moves along the circumferential direction as shown in FIGS. 4B, 4C, and 4D. When the crank angle becomes 720 degrees, the seal point S1b becomes the seal point S1c shown in FIG. 4A. From this state, when the orbiting scroll 26 further revolves half a revolution and enters the state of FIG. 4C where the crank angle is 900 degrees, the seal point S1c disappears. That is, the seal point S1a moves along the circumferential direction toward the radially inner side in the process of changing the crank angle from 0 degrees to 900 degrees.

  As with the seal point S1a, the seal point S2a moves in the radial direction along the circumferential direction. The seal point S2a becomes the seal point S2b when the crank angle is 360 degrees. As shown in FIGS. 4B and 4C, the seal point S1a that becomes the seal point S2b disappears when the crank angle is 450 degrees or more and less than 540 degrees.

  Next, the change in clearance will be described. FIG. 5 is a graph showing changes in the sizes of the clearances C1a, C1b, and C1c at the seal point S1a in the process in which the crank angle changes from 0 degrees to 900 degrees due to the revolution of the orbiting scroll 26. In the present embodiment, as shown in FIG. 5, the sizes of the clearances C1a, C1b, and C1c linearly and monotonously decrease as the crank angle increases.

(3) Features (3-1)
In the present embodiment, the clearance, which is a radial gap formed between the first lap 24b and the second lap 26b, decreases linearly and monotonously as the crank angle increases due to the revolution of the orbiting scroll 26. The inner clearance is narrower than the radially outer clearance.

  Therefore, it is possible to prevent a state in which the radially outer clearance becomes narrower than the radially inner clearance during the revolution of the orbiting scroll 26. If this happens, the first wrap 24b and the second wrap 26b are in contact with each other at the seal point in the vicinity of the second winding end point PE2 of the second wrap 26b. A clearance is formed at the seal point near the winding start point PS2. At this time, in the compression chamber near the second winding start point PS2, the compressed refrigerant gas immediately before being discharged leaks to the adjacent compression chamber under a lower pressure through the clearance. As a result, there is a possibility that leakage loss, which is power loss due to the compressed refrigerant gas leaking out, is generated again. In a general scroll compressor, the compression chamber at the center of the wrap has a larger pressure difference with the adjacent compression chamber than the compression chamber at the outer periphery of the wrap. The compression efficiency of the refrigerant gas may be greatly reduced.

  Therefore, in the present embodiment, the orbiting scroll 26 is formed so that the radially inner clearance is narrower than the radially outer clearance, thereby reducing leakage loss and suppressing a decrease in refrigerant gas compression efficiency. be able to.

(3-2)
FIG. 8 is a graph showing an example of the relationship between the clearance and the crank angle in the conventional scroll compressor for “ideal value” and “measured value”. As shown by the alternate long and short dash line labeled “ideal value” in FIG. 8, the clearance is ideally constant regardless of the crank angle. However, the second lap 26b of the orbiting scroll 26 is in a cantilever state in which the tooth bottom is supported only by the second end plate 26a, and the teeth are easily bent during processing. Further, when the side surface of the second lap 26b is processed using an end mill, the tooth thickness of the second wrap 26b may become thicker than the design value due to the spring back generated when the end mill is removed after the processing. . In particular, the radially outer portion of the second wrap 26b having a large radius of curvature is more likely to bend at the time of machining and more likely to generate springback than the radially inner portion, so that it may be difficult to achieve contour accuracy. . Therefore, as shown by the solid line labeled “actual value” in FIG. 8, in the conventional scroll compressor, the clearance on the radially outer side is generally narrower than the clearance on the radially inner side, so that leakage loss is reduced. May occur.

  However, in the present embodiment, the clearance, which is a radial gap formed between the first lap 24b and the second lap 26b, linearly and monotonously decreases as the crank angle increases due to the revolution of the orbiting scroll 26. The thickness of the second wrap 26b is designed and molded.

  Therefore, in the present embodiment, it is possible to manufacture a scroll compressor with low leakage loss without improving the contour accuracy when processing the second lap 26b of the orbiting scroll 26.

(4) Modification (4-1) Modification 1A
In the present embodiment, the second gap reduction region of the second wrap 26b is formed from the second winding end point PE2 to the second winding start point PS2, but from the second winding end point PE2 to the intermediate point. It may be formed. This intermediate point is a point located between the second winding end point PE2 and the second winding start point PS2 along the circumferential direction of the second wrap 26b. In the region excluding the second gap reduction region, that is, the region extending from the intermediate point to the second winding start point PS2, the clearance is constant.

  In the present modification, for example, as shown in FIG. 3, a point advanced substantially one turn in the circumferential direction from the second winding end point PE2 may be set as the intermediate point PM1. FIG. 6 is a graph showing the relationship between the clearance and the crank angle in this case. In this modification, the clearance decreases linearly and monotonously as the crank angle increases in the range of the crank angle from 0 degrees to 360 degrees, and the clearance becomes constant in the range of the crank angle from 360 degrees to 900 degrees. Thus, the second wrap 26b is formed.

  As another form of the present modification, a point advanced from the second winding end point PE2 by approximately one turn and a quarter turn in the circumferential direction may be set as the intermediate point PM2. In this case, when the crank angle is in the range of 0 to 450 degrees, the clearance decreases linearly and monotonously as the crank angle increases, and in the range of the crank angle from 450 to 900 degrees, the clearance becomes constant. Secondly, the second wrap 26b is formed.

  In the present modification, in the second gap reduction region from the second winding end point PE2 to the intermediate point of the second wrap 26b, the clearance linearly and monotonously decreases from the second winding end point PE2 toward the intermediate point. The second wrap 26b is formed. In this modification, a scroll compressor with low leakage loss can be manufactured by providing the second gap reduction region only in the radially outer portion where it is difficult to produce the contour system.

(4-2) Modification 1B
In the present embodiment, the clearance difference that is the difference between the clearance when the crank angle is 0 degree and the clearance when the crank angle is 900 degrees is not calculated, but this clearance difference is the contour degree of the fixed scroll 24. And may be calculated based on the contour of the orbiting scroll 26. Here, the contour level is based on the geometrical contours of the fixed scroll 24 and the orbiting scroll 26 (hereinafter referred to as “theoretical contour”) determined based on theoretically accurate dimensions. This is an amount representing the magnitude of the actual outline deviation of the fixed scroll 24 and the orbiting scroll 26. Specifically, the maximum degree of deviation between the theoretical contour and the actual contour when the theoretical contour and the actual contour are appropriately overlapped is defined as the degree of contour. Here, in order to properly overlap the theoretical contour with the actual contour, the sum of the squares of the magnitudes of the actual contour deviation measured at many points of the actual contour is minimized. Thus, the theoretical contour is superimposed on the actual contour.

  In the present modification, an arithmetic average of the contour degree of the fixed scroll 24 and the contour degree of the orbiting scroll 26 is set as the clearance difference. As a result, the clearance difference can be appropriately ensured without improving the contour accuracy of the fixed scroll 24 and the orbiting scroll 26, so that a scroll compressor with low leakage loss can be manufactured.

(4-3) Modification 1C
In this embodiment, as shown in FIG. 5, the clearance decreases linearly and monotonously as the crank angle increases from 0 degrees to 900 degrees, but as shown in FIG. 7, the crank angle decreases from 0 degrees to 900 degrees. As the distance increases, the clearance may tend to decrease in a stepwise manner.

  In the present modification, the second wrap 26b of the orbiting scroll 26 has a plurality of second gap reduction regions in which the clearance linearly monotonously decreases from the second winding end point PS2 side to the second winding start point PS2 side. ing. As shown in FIG. 7, the circumferential length of the second gap reduction region is very small, but the clearance linearly and monotonously decreases in the second gap reduction region. In the portion other than the second gap reduction region, the clearance is constant. Each of the second gap reduction regions is provided apart from each other by a certain crank angle of less than 360 degrees. Also in this modified example, since the radial inner clearance is narrower than the radial outer clearance, a scroll compressor with low leakage loss can be manufactured.

(4-4) Modification 1D
In this embodiment, Modification 1A to Modification 1C, the clearance of the second wrap 26b of the orbiting scroll 26 decreases linearly and monotonously from the second winding end point PS2 side to the second winding start point PS2 side. The first gap in which the first wrap 24b of the fixed scroll 24 linearly decreases monotonously from the first winding end point PS1 side to the first winding start point PS1 side, although it has the two gap reduction region. You may have a shape where a reduction area | region is formed.

  In the present modification, the second wrap 26b may not have the second gap reduction region, and only the first wrap 24b may have the first gap reduction region. Further, the first wrap 24b and the second wrap 26b may have a first gap reduction region and a second gap reduction region, respectively. Also in this modification, since the clearance tends to decrease as the crank angle increases from 0 degrees to 900 degrees, a scroll compressor with low leakage loss can be manufactured.

  The present invention is applicable to a scroll compressor.

24 fixed scroll 24a first end plate 24b first wrap 26 orbiting scroll 26a second end plate 26b second wrap 101 scroll compressor PE1 first winding end point (winding end point)
PE2 Second winding end point (winding end point)
PS1 First winding start point (winding start point)
PS2 2nd winding start point (winding start point)

Japanese Patent Laid-Open No. 11-159481

Claims (8)

A fixed scroll (24) having a first end plate (24a) and a first wrap (24b) erected while maintaining a spiral shape on one surface of the first end plate;
A second end plate (26a) and a second wrap (26b) standing upright while maintaining a spiral shape on one surface of the second end plate, while the second wrap meshes with the first wrap, Orbiting scroll (26) revolving with respect to the fixed scroll;
With
At least one of the first wrap and the second wrap is formed in a radial direction between the first wrap and the second wrap when the side surface of the first wrap and the side surface of the second lap are closest to each other. The clearance, which is a gap, has a shape that becomes smaller at the second point inside the lap radial direction than at the first point outside the lap radial direction,
Scroll compressor (101). The first wrap and the second wrap have a winding end point (PE1, PE2) that is an end portion on the outer side in the wrap radial direction and a winding start point (PS1, PS2) that is an end portion on the inner side in the wrap radial direction. And
At least one of the first wrap and the second wrap has a gap reduction region having a shape such that the clearance continuously decreases from the winding end point side to the winding start point side.
The scroll compressor according to claim 1. The gap reduction region extends from the winding end point to the winding start point.
The scroll compressor according to claim 2. The gap reduction region extends from the winding end point to an intermediate point between the winding end point and the winding start point.
The scroll compressor according to claim 2. The gap reduction region extends from the winding end point to a point for one winding from the winding end point toward the winding start point.
The scroll compressor according to claim 2. At least one of the first wrap and the second wrap has a plurality of the gap reduction regions,
The scroll compressor according to claim 2. The gap reduction region is located at a certain interval in the circumferential direction of the wrap, and has a shape such that the magnitude of the difference in clearance at both ends thereof is a constant value.
The scroll compressor according to claim 6. In at least one of the first wrap and the second wrap, the difference between the clearance at the winding end point and the clearance at the winding start point is a difference between the contour degree of the fixed scroll and the contour degree of the orbiting scroll. Has a shape that is equal to the arithmetic mean,
A scroll compressor given in any 1 paragraph of Claims 1-7.

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