JP2016023580A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll compressor capable of reducing leakage and further improving compression efficiency.SOLUTION: A scroll compressor comprises: a fixed scroll; and an orbiting scroll. A lap 21 of the fixed scroll is engaged with a lap 31 of the orbiting scroll in a state in which the laps 21 and 31 face mutual end plates, respectively. An outer circumferential coating 27 abraded by contact with a tooth bottom of the end plate of the other scroll is provided on a tooth tip 24 of the lap 21 or 31 on an outer circumference of at least one of the fixed scroll and the orbiting scroll, and a tip seal 22 is provided on the tooth tip 24 in a region R2 in which the outer circumferential coating 27 is not provided, between the tooth tip 24 and the tooth bottom in each of the fixed scroll and the orbiting scroll.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a scroll compressor.

  The scroll compressor includes a fixed scroll fixed to the housing and a turning scroll that revolves around the fixed scroll. Both the fixed scroll and the orbiting scroll are provided with a spiral wrap on one side of a disk-shaped end plate. The fixed scroll and the orbiting scroll compress the gas by reducing the volume of the compression chamber formed between both laps meshed with each other as the orbiting scroll turns.

  A seal groove is formed along the spiral direction at the tips (tooth tips) of both the fixed scroll and the orbiting scroll, and a tip seal is disposed in the seal groove. The tip seal seals the gap between the tip of the wrap and the end plate by being abutted against the end plate by the pressure of the compressed gas introduced to the back side from the innermost end of the wrap. Thus, compression efficiency is improved by reducing leakage of compressed gas.

  However, as shown in FIG. 13A, spirals are formed between the tooth tip 101 and the end plate (tooth bottom 102) where the tooth tip 101 is opposed on both sides in the width direction of the seal groove 106 in which the chip seal 100 is disposed. A leakage path 103 exists along the direction of. The leakage path 103 communicates with a minute gap Sp between the side surface 104 of the wrap and the side surface 105 of the wrap that defines the compression chamber. The gas flowing into the leakage path 103 through the gap Sp leaks along the direction of the spiral from the inner peripheral side (high pressure side), which is the center side of the scroll, to the outer peripheral side (low pressure side).

Here, in order to reduce the leakage by reducing the cross-sectional area of the leakage path 103, it is desirable to reduce the clearance Cr1 between the tooth tip 101 and the tooth bottom 102 on both sides of the seal groove 106. However, if the clearance Cr1 is reduced, the tooth tip 101 and the tooth bottom 102 may come into contact with each other and seize.
Therefore, in patent document 1, the coating film formed from the fluorine-type resin is formed in the tooth tip 101. FIG. When this coating film is worn away when it comes into contact with the tooth bottom, the gap between the tooth tip 101 and the tooth bottom 102 can be closed without causing seizure, and the cross-sectional area of the leakage path 103 can be reduced. Such a coating film is called abradable coating. In patent document 1, the coating film is provided in the front end surface of the outer peripheral side of a wrap.

JP 2010-150966 A

In order to realize a highly efficient scroll compressor, it is important to appropriately provide a tip seal and an abradable coating that are directly related to the reduction of compressed gas leakage.
Accordingly, an object of the present invention is to provide a scroll compressor that can reduce leakage and further improve the compression efficiency.

According to the study by the inventors of the present invention, the following can be said based on the behavior of the tip seal, abradable coating, and lap accompanying the operation of the scroll compressor.
The temperature of the scroll is higher as it is closer to the center where the gas is compressed to the maximum. And the thermal expansion of the scroll wrap increases the height of the wrap as it is closer to the center of the scroll.
Furthermore, the amount of lap elongation varies depending on the operating conditions of the scroll compressor. During operation where the pressure ratio of the scroll compressor is large, the scroll is heated by the compressed gas and becomes high temperature, so that the amount of lap elongation is large. In comparison, the amount of lap elongation is small during operation where the pressure ratio is small.
This variation in the amount of elongation can affect the leakage of the sealed portion due to the abradable coating. When the pressure ratio is large on the inner circumference side of the scroll where the amount of lap stretch is large, the lap stretches greatly during operation, and if the abradable coating wears out of contact with the tooth bottom, the pressure ratio is small thereafter. Sometimes there is a wide gap between the tip of the wrap and the bottom of the tooth, which increases the amount of leakage.

  Therefore, it is difficult to sufficiently seal the inner peripheral side of the scroll having a large amount of wrap even if the abradable coating is used alone. As shown in FIG. 13B, the tip seal 100 is used together with the abradable coating 107 to seal the gap Sp2 formed when the abradable coating 107 is worn and operated at a low pressure ratio. It is essential.

  On the other hand, since the outer peripheral side of the scroll has less thermal expansion of the lap than the inner peripheral side, the fluctuation in the amount of lap elongation due to the operating conditions is small. In particular, on the outer peripheral side of the scroll, the range in contact with the gas introduced into the outermost compression chamber is cooled by the gas, so that the height of the wrap hardly fluctuates.

  Further, as shown in FIG. 13B, the tip seal 100 floats with respect to the bottom of the seal groove 106 by the pressure of the compressed gas introduced into the seal groove 106 of the wrap tooth tip 101. The gap between the tooth tip 101 and the tooth bottom 102 is sealed. A back pressure chamber 108 is formed on the back side of the chip seal 100. The back pressure chamber 108 is formed along the spiral direction, and the compressed gas leaks to the outer peripheral side through the back pressure chamber 108.

The scroll compressor of the present invention made based on the knowledge described above includes a fixed scroll and a turning scroll.
The wraps of the fixed scroll and the orbiting scroll are meshed with each other so as to face the other end plate.
According to the present invention, an outer peripheral coating that is worn by contact with the tooth bottom of the mating end plate is provided on the tooth tip of the wrap on the outer peripheral side of at least one of the fixed scroll and the orbiting scroll. In each of the above, a tip seal is provided between the tooth tip of the region where the outer peripheral coating is not provided and the tooth bottom.

  In the present invention, the inner peripheral side of the scroll means the center side of the scroll where the gas is compressed to the maximum. The outer peripheral side of the scroll refers to the periphery of the inner peripheral side in the scroll.

As described above, since the fluctuation in the amount of lap stretch due to operating conditions is small on the outer peripheral side of the scroll, after the outer peripheral coating is worn by contact with the tooth bottom, it is also operated when operated at a lower pressure ratio than at the time of wear. A sufficient sealing effect between the tooth tip and the tooth bottom can be obtained only by the outer periphery coating. Therefore, the tip seal can be eliminated on the outer peripheral side of the scroll, and only the outer peripheral coating can be provided.
If the tip seal is eliminated on the outer peripheral side of the scroll, the tip seal back pressure chamber indispensable for establishing the seal by the tip seal is eliminated. And the amount of leakage in the whole scroll can be reduced by the amount of leakage that inevitably occurs due to the back pressure chamber.
On the other hand, on the inner peripheral side of the scroll, where the fluctuation of the height of the lap is large depending on the operating conditions, it is necessary to provide a tip seal that exhibits a stable sealing ability by the back pressure regardless of the operating conditions.

As described above, the tip seal can be eliminated on the outer peripheral side of the scroll, and only the outer peripheral coating can be provided.
However, in one of the fixed scroll and the orbiting scroll, the tip seal is suitable when the height varies greatly even on the outer peripheral side.

As described above, in the present invention, the outer peripheral coating is provided on the outer peripheral side of at least one of the fixed scroll and the orbiting scroll, and the tip seal is provided in the region where the outer peripheral coating is not provided.
As a result, the back of the tip seal on the outer peripheral side of at least one of the fixed scroll and the orbiting scroll is obtained while sufficiently sealing between the tooth tip and the tooth bottom on both the inner peripheral side and the outer peripheral side of the fixed scroll and the orbiting scroll. By eliminating the pressure chamber, leakage of compressed gas can be reduced. Therefore, the compression efficiency of the scroll compressor can be improved.

In the scroll compressor of the present invention, the boundary between the inner peripheral side and the outer peripheral side of each of the fixed scroll and the orbiting scroll is preferably positioned at a rotation angle of 2.5π or less from the outermost periphery of the wrap to the inner peripheral side.
A cooling action by contact with the refrigerant before compression reaches the region from the outermost periphery of the wrap to 2.5π.
Due to the cooling action, in the region from the outermost circumference to the inner circumference to 2.5π, the amount of stretch of the wrap is sufficiently small, and there is almost no fluctuation in elongation even if the pressure ratio fluctuates. The sealing effect can be obtained with certainty.
Therefore, the boundary between the inner periphery side and the outer periphery side of the scroll is set to a range of 2.5π or less from the outermost periphery of the wrap to the inner periphery side, and only the outer periphery coating is provided in the region located on the outer periphery side from the boundary. A tip seal may be provided in a region located on the inner peripheral side of the boundary.

Further, the boundary between the inner peripheral side and the outer peripheral side of each of the fixed scroll and the orbiting scroll is preferably positioned at a rotation angle of 1.0π or more from the outermost peripheral side to the inner peripheral side of the wrap.
Even if a tip seal is provided in an area of less than 1.0π from the outermost periphery to the inner periphery, the tip seal can be surely floated by ensuring a sufficient differential pressure between the pressure on the surface side of the tip seal and the back pressure. It can be difficult.
Therefore, the boundary between the inner peripheral side and the outer peripheral side of the scroll is set to a range of 1.0π to 2.5π from the outermost periphery of the wrap to the inner peripheral side, and the region located on the outer peripheral side from the boundary It is preferable to provide only the outer peripheral coating and provide a chip seal in a region located on the inner peripheral side from the boundary.

In the scroll compressor of the present invention, it is preferable that the tooth tip in the region where the outer peripheral coating is not provided is provided with a coating that is worn by contact with the tooth bottom in addition to the tip seal.
Such a coating can be provided on the tip of the wrap located on both sides in the width direction of the seal groove where the chip seal is disposed, or on the surface of the chip seal.
Since the space between the tooth tip and the tooth bottom is occupied by the coating, the cross-sectional area of the leakage path in the entire scroll is reduced by the occupied space, so that leakage can be reduced.

  In the scroll compressor of the present invention, both the fixed scroll and the orbiting scroll wrap are lowered in height from the outer peripheral side to the inner peripheral side through the step portion, and both the fixed scroll and the orbiting scroll end plate, It is preferable that a stepped wall that rises following the stepped portion of the counterpart lap is formed, and the boundary between the inner peripheral side and the outer peripheral side of each of the fixed scroll and the orbiting scroll is at the position of the stepped portion.

  If the boundary between the inner peripheral side and the outer peripheral side of the scroll is determined at the position of the step portion of the wrap, it is only necessary to provide the tip seal only on the inner wrap side of the step portion. Therefore, it is possible to realize a reduction in the number of parts and a cost reduction as compared with the conventional scroll compressor that requires chip seals on both the inner peripheral side and the outer peripheral side of the stepped portion.

  ADVANTAGE OF THE INVENTION According to this invention, the scroll compressor which can reduce a leak and can aim at the further improvement of compression efficiency can be provided.

It is a longitudinal cross-sectional view of the scroll compressor which concerns on 1st Embodiment. It is a top view which fractures | ruptures the wrap of a turning scroll and shows a fixed scroll and a turning scroll. (A) is a top view which shows the front-end | tip of the wrap of a fixed scroll, (b) is a top view which shows the front-end | tip of the wrap of a turning scroll. It is a schematic diagram which expand | deploys and shows the lap | wrap of the range shown by the IV-IV line | wire of FIG. FIG. 4 is an arrow view of the VV line located on the outer peripheral side in FIG. 3, (a) shows a state when operated at a high pressure ratio, and (b) shows a state when operated at a low pressure ratio. Indicates. FIG. 4 is an arrow view of the VI-VI line located on the inner peripheral side in FIG. 3, (a) shows a state when operated with a large pressure ratio, and (b) shows a state when operated with a small pressure ratio. Indicates the state. It is a schematic diagram which shows the modification of 1st Embodiment. It is a longitudinal cross-sectional view of the scroll compressor of 2nd Embodiment. It is a top view which fractures | ruptures the wrap of a turning scroll and shows a fixed scroll and a turning scroll. (A) is a top view which shows the front-end | tip of the wrap of a fixed scroll, (b) is a top view which shows the front-end | tip of the wrap of a turning scroll. It is a schematic diagram which expand | deploys and shows the lap | wrap of the range shown by the XI-XI line of FIG. It is a schematic diagram which shows the modification of 2nd Embodiment. It is a schematic diagram which shows the leak path | route in the conventional structure.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
[First Embodiment]
A scroll compressor 10 shown in FIG. 1 houses a fixed scroll 20, a turning scroll 30 that revolves around the fixed scroll 20, a motor 11 that outputs a rotational force that rotates the turning scroll 30, and these. And a cylindrical housing 14.
The scroll compressor 10 constitutes an air conditioner, and compresses the refrigerant supplied from the suction pipe 16 into the housing 14 between the fixed scroll 20 and the orbiting scroll 30. The refrigerant compressed by the scroll compressor 10 is discharged to a refrigerant circuit (not shown) through the discharge pipe 17.

The motor 11 includes a stator 12 and a rotor 13. By energizing the coil of the stator 12 and rotating the rotor 13, the motor 11 outputs a rotational force. The rotational force of the motor 11 is transmitted to the shaft 15 coupled to the rotor 13.
The scroll compressor 10 is controlled by a control device that controls the number of rotations of the motor 11 such that the compression capacity is variable.
The shaft 15 is rotatably supported by an upper bearing 19A and a lower bearing 19B provided in the housing 14.
An eccentric pin 151 that is eccentric with respect to the axis is provided at the upper end of the shaft 15.

The fixed scroll 20 includes a fixed end plate 200 and a spiral wrap 21 that rises from one surface side of the fixed end plate 200.
The wrap 21 is formed at a constant height from the outermost periphery 211 to the innermost periphery 212.
The orbiting scroll 30 includes an orbiting end plate 300 and a spiral wrap 31 that rises from one surface side of the orbiting end plate 300.
The wrap 31 is formed at a constant height from the outermost periphery 311 to the innermost periphery 312.

The fixed scroll 20 is fixed to the inner periphery of the housing 14. The center axis of the fixed scroll 20 coincides with the axis of the shaft 15.
The orbiting scroll 30 is coupled to the above-described eccentric pin 151 by a boss 34 provided on the back surface of the orbiting end plate 300. When the shaft 15 rotates, the orbiting scroll 30 is revolved with respect to the fixed scroll 20 while being prevented from rotating by an Oldham ring (not shown).

As shown in FIG. 2, the wrap 21 of the fixed scroll 20 and the wrap 31 of the orbiting scroll 30 are eccentric with each other by a predetermined amount, and are engaged with each other with a phase difference of 180 degrees.
A compression chamber 18 is formed between the fixed scroll 20 and the orbiting scroll 30 in point symmetry with respect to the center of the spiral of the wraps 21 and 31.
When the turning scroll 30 is turned with respect to the fixed scroll 20, the refrigerant introduced into the housing 14 from the suction pipe 16 is formed between the outermost circumference 211 of the wrap 21 and the side wall of the wrap 31. And the suction port 310 formed between the outermost periphery 311 of the wrap 31 and the side wall of the wrap 21 is sucked into the space between the scrolls 20 and 30. These inlets 210 and 310 are periodically opened and closed when the orbiting scroll 30 is orbited.
FIG. 2 shows a pair of compressions positioned on the outermost peripheral side when the suction ports 210 and 310 are closed and the side surface of the wrap 21 and the side surface of the lap 31 are in contact with each other at the back side of the suction ports 210 and 310. The state where the chamber 18 is closed is shown.
As the orbiting scroll 30 turns, the compression chamber 18 is gradually driven toward the inner peripheral side while reducing the volume. The refrigerant in the compression chamber 18 is discharged from a discharge port 201 (FIG. 1) formed at the center of the spiral in the fixed end plate 200.

  The thrust load applied to the orbiting scroll 30 by the pressure of the compressed refrigerant is supported by an annular thrust plate 35 (FIG. 1) provided on the upper bearing 19A. The thrust plate 35 is a thrust sliding bearing.

In order to suppress the leakage of the refrigerant from the compression chamber 18, between the turning end plate 300 facing the tip of the wrap 21 of the fixed scroll 20 and between the fixed end plate 200 facing the tip of the wrap 31 of the turning scroll 30. Between them, a chip seal 22 and abradable coatings 23 and 27 are provided, respectively.
Here, the tip of each of the wraps 21 and 31 is referred to as a tooth tip 24, and the point where the tooth tip 24 faces in each of the mating end plates 200 and 300 where the tips of the wraps 21 and 31 face each other. This is referred to as the tooth bottom 25 (FIG. 4).

  As shown in FIG. 3A, a tip seal 22 is provided on the tooth tip 24 of the wrap 21 of the fixed scroll 20 along the spiral direction of the wrap 21. The tip seal 22 is provided on the tooth tip 24 positioned on the inner peripheral side of the fixed scroll 20, and is not provided on the tooth tip 24 positioned on the outer peripheral side of the fixed scroll 20.

The chip seal 22 is made of resin or metal and has a rectangular cross section.
The tip seal 22 is disposed in a seal groove 26 formed in the tooth tip 24 of the wrap 21 of the fixed scroll 20.
As shown in FIGS. 4 and 6A, the seal groove 26 is formed so as to be dug into a rectangular shape from the distal end surface 24 </ b> A of the wrap 21 toward the proximal end of the wrap 21.
In FIG. 4, the seal groove 26 is indicated by a one-dot chain line. The same applies to FIG.

In the innermost circumference 212 of the wrap 21 (FIG. 3A), a gap G is formed between the end portion of the tip seal 22 and the inner wall of the seal groove 26 facing it. From this gap G, a sufficiently compressed refrigerant is introduced to the back side of the chip seal 22 and flows along the seal groove 26. Then, since the pressure on the front surface side of the tip seal 22 becomes negative pressure on the back surface side, the tip seal 22 rises with respect to the bottom surface of the seal groove 26 as shown in FIG. Hit. Thus, the tip seal 22 seals between the tooth tip 24 and the tooth bottom 25.
The same applies to the tip seal 22 provided on the wrap 31.

On the inner peripheral side of the fixed scroll 20, an inner peripheral abradable coating 23 (hereinafter referred to as inner peripheral coating) is provided on both sides in the width direction of the seal groove 26 on the front end surface 24 </ b> A of the wrap 21, as shown in FIG. 23). The inner periphery coating 23 is illustrated in a dot pattern.
The inner peripheral coating 23 is worn away when it contacts the tooth bottom 25 during operation of the scroll compressor 10, thereby keeping the clearance formed between the tooth tip 24 and the tooth bottom 25 to a minimum. In the following description, it is described that the clearance formed between the tooth tip 24 and the tooth bottom 25 is kept to a minimum by abrasion, and that the space between the tooth tip 24 and the tooth bottom 25 is blocked. The same applies to the outer peripheral coating 27 described later.
As much as the inner peripheral coating 23 is worn, the leakage path is cut off while preventing seizure between the tooth tip 24 and the tooth bottom 25 without requiring strict control of the clearance between the tooth tip 24 and the tooth bottom 25. Leakage can be reduced by reducing the area.

  In other words, when the inner peripheral coating 23 is not provided, the leakage path 103 present beside the seal groove 106 is occupied by the inner peripheral coating 23 as shown in FIG. When the leakage path 103 shown in FIG. 13A exists, the leakage path is formed from a minute gap Sp formed due to tolerance, surface roughness, or the like between the side surface of the wrap that partitions the compression chamber and the side surface of the wrap. The compressed refrigerant flows into 103 and leaks along the leakage path 103 to the outer peripheral side. Accordingly, when the leakage path 103 is occupied by the inner peripheral coating 23, the cross-sectional area of the entire path through which the compressed refrigerant leaks is reduced by the occupied amount, so that leakage can be reduced.

The inner peripheral coating 23 (FIG. 3A) can be formed of a resin material such as an epoxy resin or a fluorine resin, for example. Examples of the fluororesin include PTFE (polytetrafluoroethylene). Further, as the inner peripheral coating 23, for example, a solid lubricant such as molybdenum disulfide can be provided.
In addition, the inner peripheral coating 23 can be formed from any material that wears away by contact with the tooth bottom 25, including metal materials and ceramic materials.
Any of the above materials can be applied to the outer periphery coating 27 described later.
The inner peripheral coating 23 and the outer peripheral coating 27 are not necessarily formed from the same material.

  An outer peripheral abradable coating 27 (hereinafter referred to as an outer peripheral coating 27) is applied to the entire front end surface 24A of the tooth tip 24 of the wrap 21 on the outer peripheral side of the fixed scroll 20 without forming a seal groove 26. . The outer periphery coating 27 is also illustrated in a dot pattern.

The distance from the outermost circumference 211 of the wrap 21 to the inner circumference side of 2π [rad] corresponds to the rotation angle from when the suction ports 210 and 310 (FIG. 2) are opened to when they are closed. The wrap 21 in the range of the rotation angle comes into contact with the refrigerant before compression sucked into the compression chamber 18.
The outer peripheral coating 27 is provided from the outermost periphery 211 of the wrap 21 to the inner peripheral side over the outer peripheral region R1 up to 2π.
In the wrap 21, the above-described tip seal 22 and the inner peripheral coating 23 are provided in the remaining inner peripheral region R <b> 2.
That is, the boundary B between the outer peripheral region R1 and the inner peripheral region R2 in the lap 21 is located at 2π from the outermost periphery 211 of the wrap 21 toward the inner peripheral side.

  Similarly to the inner peripheral coating 23, the outer peripheral coating 27 wears away when contacting the tooth bottom 25 during operation of the scroll compressor 10, thereby closing the space between the tooth tip 24 and the tooth bottom 25. The cross-sectional area of the leakage path while preventing seizure between the tooth tip 24 and the tooth bottom 25 without requiring strict control of the clearance between the tooth tip 24 and the tooth bottom 25 as much as the outer peripheral coating 27 is worn away. Can be reduced to reduce leakage.

The outer periphery coating 27 can be formed from the same material as the inner periphery coating 23.
In the present embodiment, as shown in FIG. 4, the outer peripheral coating 27 and the inner peripheral coating 23 are formed to have the same thickness. The inner peripheral coating 23 and the outer peripheral coating 27 can be continuously formed by a coater device that supplies a coating material having fluidity to the tip surface 24A of the wrap 21.
The inner peripheral coating 23 and the outer peripheral coating 27 can be formed by any method such as painting, plating, chemical vapor deposition, or physical vapor deposition.
The inner peripheral coating 23 and the outer peripheral coating 27 can be composed of one or more layers.

  The inner periphery coating 23 and the outer periphery coating 27 of this embodiment are formed in the thickness of about 10-100 micrometers, for example. On the other hand, the chip seal 22 is formed to a thickness of about 1.0 to 5 mm, for example.

Next, as shown in FIG. 3B, the tip seal 22, the inner peripheral coating 23, and the outer peripheral coating 27 are also provided on the tooth tip 24 of the orbiting scroll 30 in the same manner as the fixed scroll 20. Also in the orbiting scroll 30, the outer peripheral coating 27 is provided over the outer peripheral region R1 from the outermost periphery 311 of the wrap 31 to the inner peripheral side up to 2π.
In the wrap 31, a tip seal 22 and an inner peripheral coating 23 are provided in the remaining inner peripheral region R <b> 2.

  In the present embodiment, in each of the fixed scroll 20 and the orbiting scroll 30, the tip seal 22 is provided on the inner peripheral side, and the tip seal 22 is not provided on the outer peripheral side, and wears by contact with the tooth bottom 25. The main feature is that a peripheral coating 27 is applied.

  As described above, when the orbiting scroll 30 is orbited, the compression chamber 18 gradually moves to the inner peripheral side while reducing the volume. Along with this, the refrigerant compression process proceeds, and the refrigerant is compressed to the maximum at the center of the scrolls 20 and 30. The refrigerant increases in temperature as the pressure increases and dissipates heat to the scrolls 20 and 30. Therefore, the temperatures of the scrolls 20 and 30 are higher as they are closer to the center. And the height of the wraps 21 and 31 is extended by thermal expansion as it is closer to the center of the scrolls 20 and 30.

ｎはポリトロープ指数である。
この式より、圧力比が大きいほど、圧縮前の温度と圧縮後の温度（つまりラップ外周部と内周部の温度）に差がつく。
ラップの伸び量の変動は、スクロール２０，３０において中心側（内周側）に設けられた内周コーティング２３による封止に影響する。
一方、スクロール２０，３０の外周側では、ラップ２１，３１の伸び量が殆ど変動しないことから、外周コーティング２７による封止には殆ど影響がない。以下、説明する。 The amount of expansion of the wraps 21 and 31 due to thermal expansion varies depending on the operating conditions of the scroll compressor 10.
When the scroll compressor 10 is operated under a condition where the pressure ratio (pressure after compression / pressure before compression) is large, the scrolls 20 and 30 are heated by the compressed refrigerant and become high temperature. large. In contrast, the amount of elongation of the laps 21 and 31 is small during operation where the pressure ratio is small.
The relationship between temperature and pressure during compression is shown in the following equation.

n is a polytropic index.
From this equation, the greater the pressure ratio, the greater the difference between the pre-compression temperature and the post-compression temperature (that is, the temperature of the wrap outer periphery and inner periphery).
The fluctuation of the wrap elongation amount affects the sealing by the inner peripheral coating 23 provided on the center side (inner peripheral side) of the scrolls 20 and 30.
On the other hand, on the outer peripheral side of the scrolls 20 and 30, the amount of elongation of the wraps 21 and 31 hardly fluctuates, so that the sealing by the outer peripheral coating 27 is hardly affected. This will be described below.

5A and 5B show wraps 21 and 31 located on the outer peripheral sides of the fixed scroll 20 and the orbiting scroll 30, respectively. FIG. 5A shows a state when the scroll compressor 10 is operated with a relatively large pressure ratio, and FIG. 5B shows a state when the scroll compressor 10 is operated with a relatively small pressure ratio. Indicates the state.
When the scroll compressor 10 is operated, as shown in FIG. 5A, the height of the wrap 21 extends from the height H0 at the normal temperature indicated by the one-dot chain line to the height H1. Accordingly, when the outer peripheral coating 27 comes into contact with the tooth bottom 25, the outer peripheral coating 27 is worn down to a thickness corresponding to the gap S1 even if the outer peripheral coating 27 is formed with a thickness larger than the gap S1 between the tooth tip 24 and the tooth bottom 25. The gap between the tooth tip 24 and the tooth bottom 25 is closed.
Further, the height of the wrap 31 extends in the same manner as the wrap 21, and when the outer peripheral coating 27 provided on the tooth tip 24 comes into contact with the tooth bottom 25, the outer peripheral coating 27 becomes a gap S 1 between the tooth tip 24 and the tooth bottom 25. To a thickness corresponding to the thickness of the tooth, and the gap between the tooth tip 24 and the tooth bottom 25 is blocked. Note that the gap S1 between the tooth tip 24 of the wrap 21 and the tooth bottom 25 facing the tooth root 25 does not necessarily match the gap S1 between the tooth bottom 25 of the lap 31 facing the tooth tip 24.
A space between the tooth tips 24 of the wraps 21 and 31 and the opposite tooth bottom 25 is sealed by the outer peripheral coating 27 over the entire thickness of the teeth.
By the wear of the outer peripheral coating 27, the clearance C1 formed between the tooth tip 24 and the tooth bottom 25 is kept to a minimum. The clearance C1 is formed between the surface of the outer peripheral coating 27 and the tooth bottom 25, and since the amount of refrigerant leaking through the clearance C1 is very small, there is a gap between the tooth tip 24 and the tooth bottom 25. There is virtually no leakage path. The leakage path is limited to the gap Sp between the side surface 21S of the wrap 21 and the side surface 31S of the wrap 31 that define the compression chamber 18.

As shown in FIG. 5A, it is assumed that after the outer peripheral coating 27 is worn, it is operated at a pressure ratio smaller than the operating condition at the time of wear. Here, since the temperature of the refrigerant does not rise on the outer peripheral side of the scrolls 20 and 30 from which the compression process starts, the wraps 21 and 31 are also operated when operated at a large pressure ratio (FIG. 5A). It is not growing so much. Therefore, the difference between the height H2 of the wrap 21 when the pressure ratio is small as shown in FIG. 5B and the height H1 of the wrap 21 during wear is small. The same applies to the height of the wrap 31.
And since it cools by contacting with the refrigerant | coolant suck | inhaled between the scrolls 20 and 30 from the circumference | surroundings of the scrolls 20 and 30, the expansion amount of the wraps 21 and 31 is suppressed over outer peripheral area | region R1. Also in this respect, the difference between the height H1 of the wraps 21 and 31 when the pressure ratio is large and the height H2 of the wraps 21 and 31 when the pressure ratio is small is small.
Accordingly, even if the outer peripheral coating 27 is worn by the operation with a large pressure ratio and is operated with a small pressure ratio, the clearance C1 formed between the tooth tip 24 and the tooth bottom 25 is still kept to a minimum. The That is, the space between the tooth tip 24 and the tooth bottom 25 is sufficiently closed by the outer peripheral coating 27.
As described above, on the outer peripheral side of the scrolls 20 and 30, fluctuations in the amount of extension of the wraps 21 and 31 according to the operating conditions hardly affect the sealing by the outer peripheral coating 27.

On the outer peripheral side of the scrolls 20 and 30, it is necessary to use the tip seal 22 because a sufficient sealing effect between the tooth tip 24 and the tooth bottom 25 can be obtained only by the outer peripheral coating 27 regardless of the operating conditions. There is no. For this reason, in this embodiment, the tip seal 22 is eliminated on the outer peripheral side of the scrolls 20 and 30, and only the outer peripheral coating 27 is provided.
If the chip seal 22 is eliminated, the refrigerant does not leak through the back pressure chamber on the back side of the chip seal 22. This back pressure chamber is a space S2 between the back surface of the chip seal 22 and the bottom surface of the seal groove 26, as shown in FIG. This space S2 is inevitably generated in realizing a mechanism for sealing between the tooth tip 24 and the tooth bottom 25 by introducing the back pressure to raise the tip seal 22.
In the present embodiment, on the outer peripheral side of the scrolls 20 and 30, the seal between the tooth tip 24 and the tooth bottom 25 is held only by the outer peripheral coating 27 without using the tip seal 22 together. S2 can be eliminated. The amount of leakage in the entire scrolls 20 and 30 can be reduced by the amount of the space S2.

On the other hand, on the inner peripheral side of the scrolls 20 and 30 where the amount of elongation of the wraps 21 and 31 is large, variation in the amount of expansion of the wraps 21 and 31 according to the operating conditions affects the sealing by the inner peripheral coating 23. This will be described below.
6A and 6B show wraps 21 and 31 located on the inner peripheral side of each of the fixed scroll 20 and the orbiting scroll 30. 6A shows a state when the scroll compressor 10 is operated with a relatively large pressure ratio, and FIG. 6B shows a state when the scroll compressor 10 is operated with a relatively small pressure ratio. Indicates the state.
When the scroll compressor 10 is operated, as shown in FIG. 6A, the height of the wrap 21 extends from a height H0 at normal temperature indicated by a one-dot chain line to a height H1. Accordingly, when the inner peripheral coating 23 comes into contact with the tooth bottom 25, the inner peripheral coating 23 is worn down to a thickness corresponding to the gap S3 between the tooth tip 24 and the tooth bottom 25, and the tooth tip 24, the tooth bottom 25, Block between.
The height of the wrap 31 extends in the same manner as the wrap 21, and the inner peripheral coating 23 of the wrap 31 is also worn down to a thickness corresponding to the gap S3 between the tooth tip 24 and the tooth bottom 25, and the tooth tip 24 and the tooth bottom 25 Block between. Note that the gap S3 between the tooth tip 24 of the wrap 21 and the tooth bottom 25 facing the tooth root 25 does not necessarily match the gap S3 between the tooth bottom 25 of the lap 31 facing the tooth tip 24.
Here, on the inner peripheral side of the scrolls 20 and 30 corresponding to the final process from the middle of the compression, the temperature rise due to the increase in the pressure of the refrigerant is significant, and the amount of heat released from the compressed refrigerant during operation with a large pressure ratio. Since there are many, the elongation amount of the wraps 21 and 31 is large.

As shown in FIG. 6A, it is assumed that after the inner peripheral coating 23 is worn out, it is operated at a pressure ratio smaller than the operating condition at the time of wear. Here, the height of the wraps 21 and 31 greatly depends on the temperature of the compressed refrigerant that comes into contact therewith. As shown in FIG. 6B, the height H2 of the wraps 21, 31 when the pressure ratio is small is lower than the height H1 of the wraps 21, 31 at the time of wear. Therefore, there is a gap S4 between the tooth tip 24 and the tooth bottom 25 that is larger than the gap S3 in FIG.
Here, since the abradable coating is not restored once it is worn out, if S4> S3, there is a gap Sp2 between the surface of the inner peripheral coating 23 and the tooth bottom 25, and the tooth tip 24 and the tooth bottom 25 Cannot be sufficiently sealed by the inner peripheral coating 23.

As described above, even when the inner peripheral coating 23 is provided, there is a gap Sp <b> 2 between the tooth tip 24 and the tooth bottom 25 depending on the extension amount of the wraps 21 and 31. On the other hand, since the tip seal 22 floats due to the back pressure even if the amount of extension of the wraps 21 and 31 varies, the tip seal 22 can abut against the tooth bottom 25. That is, the tip seal 22 exhibits a stable sealing ability regardless of operating conditions.
Therefore, it is necessary to provide the tip seal 22 without depending on the inner peripheral coating 23 on the inner peripheral side of the scrolls 20 and 30 where the variation of the expansion amount of the laps 21 and 31 is large according to the operating conditions. On the inner peripheral side of the scrolls 20 and 30, it is necessary to provide at least the tip seal 22 of the tip seal 22 and the inner peripheral coating 23 as a mechanism for sealing between the tooth tip 24 and the tooth bottom 25. The tip seal 22 is essential on the inner peripheral side of the wraps 21 and 31, but the inner peripheral coating 23 can be omitted.

  If the inner peripheral coating 23 is provided as in the present embodiment, the space between the tooth tip 24 and the tooth bottom 25 is occupied, thereby reducing the cross-sectional area of the leakage path and contributing to reducing leakage. . Therefore, as in this embodiment, the inner peripheral coating 23 can be provided in addition to the chip seal 22 on the inner peripheral side of the scrolls 20 and 30.

  As described above, in the present embodiment, the tip seal 22 is provided on the inner peripheral side of the scrolls 20, 30, and only the outer peripheral coating 27 is provided on the outer peripheral side of the scrolls 20, 30 without providing the tip seal 22. Provide. Thereby, the leakage of the refrigerant is reduced by eliminating the back pressure chamber of the tip seal 22 on the outer peripheral side while sufficiently sealing between the tooth tip 24 and the tooth bottom 25 on both the inner peripheral side and the outer peripheral side. be able to. Thereby, the compression efficiency of the scroll compressor 10 can be improved.

In the present embodiment, the boundary B between the outer peripheral region R1 where the outer peripheral coating 27 is provided and the inner peripheral region R2 where the tip seal 22 is provided is 1. from the outermost periphery 211, 311 of the wraps 21, 31 to the inner peripheral side. It is preferably located in the range of 0π to 2.5π. FIGS. 3A and 3B show the positions of 1.0π and 2.5π from the outermost circumferences 211 and 311 to the inner circumference side, respectively.
The region from the outermost circumference 211, 311 to 2.5π is cooled by contact with the refrigerant before compression.
Due to the cooling action, in the region from the outermost circumference 211, 311 to the inner circumference side up to 2.5π, the amount of elongation of the wraps 21, 31 is sufficiently small, and there is almost no variation in the amount of elongation even if the operating conditions change. A sufficient sealing effect can be reliably obtained by the outer peripheral coating 27 that is worn down to a predetermined thickness.
Here, even if the tip seal 22 is provided in the region of less than 1.0π from the outermost circumference 211, 311 to the inner circumference side, a sufficient differential pressure between the back pressure propagated from the high pressure portion and the pressure on the surface side is ensured. Thus, it may be difficult to assure that the chip seal 22 is lifted. The reason will be explained. On the back surface of the tip seal 22 located in a certain compression chamber 18, the pressure in the compression chamber 18 that is one tip (360 ° ahead) of the compression chamber 18 acts as a back pressure. And the pressure in the scrolls 20 and 30 increases exponentially as it goes from the outer peripheral side to the center. Therefore, as shown in FIG. 2, when there are A, B, and C compression chambers 18 from the center of the scrolls 20 and 30 to the outer peripheral side, the pressure difference between the A and B chambers, the B and C chambers, and so on. The pressure difference between the B chamber and the C chamber is smaller. That is, the tip seal 22 is less likely to float as it goes to the outer peripheral side.
From the above, it is preferable that the boundary B between the outer peripheral region R1 and the inner peripheral region R2 is set to a range of 1.0π or more and 2.5π or less from the outermost periphery 211 or 311 of the wraps 21 and 31 to the inner peripheral side. In the outer peripheral region R1 located on the outer peripheral side from the boundary B, only the outer peripheral coating 27 is provided without providing the chip seal 22, and in the inner peripheral region R2 located on the inner peripheral side from the boundary B, the chip seal is provided. 22 may be provided.

Before and after the boundary B, it is allowed that there is a seal absence portion where neither the outer peripheral coating 27 nor the tip seal 22 is provided due to manufacturing reasons. That is, the outer peripheral coating 27 and the chip seal 22 arranged with the boundary B interposed therebetween are not necessarily adjacent to each other.
In addition, it is allowed not to provide the outer peripheral coating 27 in a predetermined range from the outermost peripheral surfaces 211 and 311 of the wraps 21 and 31 that are least affected by the temperature rise of the compressed refrigerant.

  Furthermore, the boundary B between the outer peripheral region R1 and the inner peripheral region R2 is more preferably at a position of 2π or more from the outermost peripheral surfaces 211, 311 of the wraps 21, 31 to the inner peripheral side. As shown in FIG. 2, in a state where the pair of outermost compression chambers 18 are closed, the positions where the side surface of the wrap 21 and the side surface of the lap 31 are in contact (see contact point P) are the outermost periphery 211, 311. To 2π.

Here, when the volume of the refrigerant received in the compression chamber 18 located on the outermost peripheral side is large, the volume efficiency of the scroll compressor 10 can be improved.
The volumetric efficiency is such that the refrigerant of the total volume of the compression chambers 18 and 18 when the pair of compression chambers 18 and 18 positioned at the outermost periphery is closed is compressed to a predetermined pressure without leaking to the outside as it is. The ratio of the flow rate actually discharged from the compressor to the flow rate discharged from the compressor. The flow rate with a volumetric efficiency of 100% is the total volume of the compression chambers 18, 18 located on the outermost periphery, the density of the refrigerant when the outermost compression chambers 18, 18 are closed, and the rotation speed of the scroll compressor 10. Can be obtained by multiplying
When the tip seal 22 is provided on the tooth tip 24, a back pressure chamber (space S2 in FIG. 6A) is required on the back side of the tip seal 22. Due to the presence of the back pressure chamber, the effective refrigerant volume that can be received in the compression chamber 18 on the outermost peripheral side and driven into the inner peripheral side is reduced. Therefore, if the tip seal 22 is eliminated and only the outer peripheral coating 27 is provided from the outermost periphery 211 of the wrap 21 to at least 2π that defines the compression chamber 18 on the outermost periphery side, the back pressure of the tip seal 22 is provided. Volume efficiency can be improved by the amount of the chamber.
That is, the boundary B between the outer peripheral region R1 and the inner peripheral region R2 is located at 2π or more from the outermost outer periphery 211 of the wrap 21, and the tip seal 22 is not provided over the outer peripheral region R1 existing on the outer peripheral side from the boundary B. It is preferable to provide only the outer peripheral coating 27.
Although only the wrap 21 of the fixed scroll 20 has been described above, the boundary B between the outer peripheral region R1 and the inner peripheral region R2 is similarly determined from the outermost periphery 311 of the wrap 31 to 2π or more for the wrap 31 of the orbiting scroll 30. By providing only the outer peripheral coating 27 without providing the chip seal 22 over the outer peripheral region R1 existing on the outer peripheral side from the boundary B, the volume efficiency can be improved.

In the present embodiment, the height of the wraps 21 and 31 is set to the inner peripheral side so that an appropriate clearance is formed between the tooth tip 24 and the tooth bottom 25 when the wraps 21 and 31 are extended by thermal expansion. It can also be made different on the outer peripheral side. The appropriate clearance refers to a clearance that can be sufficiently sealed by the outer peripheral coating 27 or the chip seal 22 without causing seizure. The inner circumferential clearance and the outer circumferential clearance are not necessarily the same.
The above also applies to the height of the inner peripheral wraps 21A and 31A and the height of the outer peripheral wraps 21B and 31B of the second embodiment.

FIG. 7 shows a modification of the first embodiment.
Here, a method for optimizing the clearance on the back side of the tip seal 22 serving as a leakage path as well as between the tooth tip 24 and the tooth bottom 25 will be described.
The seal groove 26 'is formed so as to gradually become shallower from the inner peripheral side toward the outer peripheral side so that an appropriate clearance is formed between the back surface of the chip seal 22 and the bottom surface of the seal groove 26'. In the seal groove 26 ′, a chip seal 22 formed with a constant thickness over the entire length direction is arranged.
Here, the abradable coating 23 provided on both sides in the width direction of the chip seal 22 is scraped according to the amount of elongation of the lap. The tooth tip 24 and the tooth bottom 25 approach each other as much as the abradable coating 23 is removed. Therefore, assuming that the depth of the seal groove 26 ′ is constant, comparing one end side (outer peripheral side) and the other end side (inner peripheral side) of the tip seal 22 in the length direction, the abradable coating 23 The chip seal 22 has a larger amount of chipping than the clearance formed between the back surface of the chip seal 22 and the bottom surface of the seal groove 26 ′ (on the one end side in the length direction). The clearance formed between the back surface of the chip seal 22 and the bottom surface of the seal groove 26 ′ becomes larger at the other end in the length direction. In view of this, the depth of the seal groove 26 'is changed between the inner peripheral side and the outer peripheral side, so that the clearance between the back surface of the chip seal 22 and the bottom surface of the seal groove 26' is leveled in the circumferential direction. The amount of leakage can be reduced by optimization and optimization.
Note that a sealing groove 26 ′ similar to the above can also be formed in the lap 31 of the orbiting scroll 30.
Moreover, the same sealing groove | channel 26 'as the above can be formed also in inner peripheral wrap 21A, 31A of 2nd Embodiment.

[Second Embodiment]
Next, a second embodiment will be described with reference to FIGS.
Hereinafter, the difference from the first embodiment will be mainly described. The same code | symbol is attached | subjected to the structure similar to the structure demonstrated in 1st Embodiment.
The scroll compressor 10 _3D (FIG. 8) according to the second embodiment is a 3D type, and the volume of the compression chamber 18 formed between the fixed scroll 20 and the orbiting scroll 30 is that of the wraps 21 and 31 in the middle of the spiral. It also decreases in the height direction.
In both the fixed scroll 20 and the orbiting scroll 30, the height of the wraps 21, 31 is lower on the inner peripheral side than the outer peripheral side, and the inner peripheral side of the mating end plates 300, 200 facing the wraps 21, 31 is the outer peripheral side. It protrudes to the inner surface side.
Each of the wraps 21 and 31 is formed with step portions 21C and 31C that are lowered from the outer peripheral side to the inner peripheral side. Each of the end plates 300 and 200 is formed with step walls 20C and 30C that increase from the outer peripheral side to the inner peripheral side.

As shown in FIG. 9, the wrap 21 of the fixed scroll 20 is divided into an inner peripheral wrap 21A located on the inner peripheral side with respect to the stepped portion 21C and an outer peripheral wrap 21B positioned on the outer peripheral side with respect to the stepped portion 21C. .
The bottom portion of the turning end plate 300 facing the wrap 21 is divided into an inner peripheral bottom portion and an outer peripheral bottom portion (both not shown) with the step wall 30C as a boundary.
The step portion 21 </ b> C and the step wall 30 </ b> C are located at a position of about 2π from the outermost periphery 211 of the wrap 21 to the inner periphery side.

Further, the wrap 31 of the orbiting scroll 30 is divided into an inner peripheral lap 31A located on the inner peripheral side with respect to the stepped portion 31C and an outer peripheral wrap 31B positioned on the outer peripheral side with respect to the stepped portion 31C.
The bottom portion of the fixed end plate 200 facing the lap 31 is divided into an inner peripheral bottom portion 20A and an outer peripheral bottom portion 20B with a step wall 20C as a boundary.
The step portion 31C and the step wall 20C are at a position of about 2π from the outermost periphery 311 of the wrap 31 to the inner periphery side.

The inner peripheral wraps 21A and 31A and the outer peripheral wraps 21B and 31B are each formed at a constant height over the entire length in the circumferential direction.
In this specification, the “circumferential direction” of the lap refers to a direction along the direction of the spiral.
The outer peripheral wraps 21B and 31B come into contact with the refrigerant sucked from the suction ports 210 and 310, respectively, while the orbiting scroll 30 makes one rotation at a rotation angle of 2π.

Also in the present embodiment, as in the first embodiment, in each of the fixed scroll 20 and the orbiting scroll 30, the outer peripheral coating 27 is provided on the outer peripheral side, and the tip seal 22 is provided on the inner peripheral side.
In the fixed scroll 20, a boundary B between the outer peripheral side where the outer peripheral coating 27 is provided and the inner peripheral side where the outer peripheral coating 27 is not provided is determined at the position of the step portion 21 </ b> C.
In the orbiting scroll 30, the boundary B between the outer peripheral side where the outer peripheral coating 27 is provided and the inner peripheral side where the outer peripheral coating 27 is not provided is determined at the position of the step portion 31C.

As shown in FIG. 10A, a tip seal 22 is provided on the tooth tip 24 of the inner peripheral wrap 21 </ b> A of the fixed scroll 20. The tip seal 22 is disposed in a seal groove 26 (FIG. 11) formed in the tooth tip 24. In this embodiment, the inner peripheral coating 23 is not provided on the tooth tip 24 of the inner peripheral wrap 21A.
On the other hand, an outer peripheral coating 27 that is worn by contact with the tooth bottom 25 is applied to the entire tooth tip 24 of the tooth tip 24 of the outer peripheral wrap 21 </ b> B of the fixed scroll 20. The tip seal 22 is not provided on the tooth tip 24 of the outer peripheral wrap 21B.

  As shown in FIG. 10 (b), the orbiting scroll 30 also has a tip seal 22 on the tooth tip 24 of the inner peripheral wrap 31A and the tooth tip 24 of the outer peripheral wrap 31B. A coating 27 is applied.

  The cross sections of the outer peripheral wraps 21B and 31B are the same as those shown in FIGS. 5A and 5B corresponding to the outer peripheral sides of the wraps 21 and 31 of the first embodiment. As described with reference to FIGS. 5 (a) and 5 (b), the height of the outer wraps 21B and 31B is hardly changed even if the operating conditions are changed. The gap between the tooth tip 24 and the tooth bottom 25 can be sufficiently sealed. Therefore, the leakage of the refrigerant can be reduced by eliminating the chip seal 22 in the outer peripheral wraps 21B and 31B and eliminating the leakage of the refrigerant through the back pressure chamber of the chip seal 22.

  On the other hand, the cross sections of the inner peripheral wraps 21A and 31A are the same as those shown in FIGS. 6A and 6B corresponding to the inner peripheral side of the wraps 21 and 31 of the first embodiment. As described with reference to FIGS. 6 (a) and 6 (b), the inner circumferential side shows the amount of elongation corresponding to the operating conditions, and therefore, a tip seal 22 that can float according to the amount of elongation is provided. Thus, the gap between the tooth tip 24 and the tooth bottom 25 can be sufficiently sealed.

  According to the present embodiment, it is sufficient to provide the tip seal 22 only on the inner peripheral wraps 21A and 31A on the inner peripheral side of the stepped portions 21C and 31C. Therefore, compared with the conventional 3D type scroll compressor that requires chip seals on both the inner peripheral wrap 21A and the outer peripheral wrap 21B across the stepped portion 21C, the number of parts is reduced and the cost is thereby reduced. be able to.

  In the inner peripheral wraps 21A and 31A of the present embodiment, the inner peripheral coating 23 can be provided on the front end surfaces 24A left on both sides of the seal groove 26 as in the first embodiment. Since the inner peripheral coating 23 occupies the space between the tooth tip 24 and the tooth bottom 25, the cross-sectional area of the leakage path is reduced, so that leakage can be reduced.

The step portions 21C and 31C corresponding to the boundary B between the inner peripheral wraps 21A and 31A and the outer peripheral wraps 21B and 31B are 1.0π or more from the outermost peripheral surfaces 211 and 311 of the wraps 21 and 31, respectively. It is preferably at a position of 5π or less.
As described in the first embodiment, the cooling action by the contact with the refrigerant before compression reaches the region from the outermost periphery 211,311 to 2.5π of the wraps 21,31, and from the outermost periphery 211,311. This is because in the region of less than 1.0π toward the inner peripheral side, it may be difficult to ensure that the tip seal 22 floats by ensuring a sufficient differential pressure between the back pressure of the tip seal 22 and the pressure on the surface side. .

  In the second embodiment, the position of the boundary B between the region where the outer peripheral coating 27 is provided and the region where the outer peripheral coating 27 is not provided can be determined regardless of the positions of the step portions 21C and 31C. For example, it is allowed to set the boundary B on the inner peripheral wraps 21A and 31A and to set the boundary B on the outer peripheral wraps 21B and 31B.

When the boundary B is set on the inner peripheral wraps 21A and 31A, only the outer peripheral coating 27 without the tip seal 22 is provided on the outer peripheral side of the inner peripheral wraps 21A and 31A.
When the boundary B is set on the outer peripheral wraps 21B and 31B, the tip seal 22 is provided alone or together with the inner peripheral coating 23 on the inner peripheral side of the outer peripheral wraps 21B and 31B.

FIG. 12 shows an example in which the boundary B is set on the inner circumferential wrap 21A. In this example, the boundary B is located at the inner peripheral end of the tip seal 22, and the root portion of the step portion 21 </ b> C where the tip seal 22 is not provided in the inner peripheral wrap 21 </ b> A is brought into contact with the tooth bottom 25. A peripheral coating 28 is provided that wears away. Normally, by providing the outer peripheral coating 28 at the base of the stepped portion 21C where the tip seal 22 is not provided, leakage of refrigerant from the base of the stepped portion 21C is prevented, and the tooth tips are continuously formed from the inner peripheral wrap 21A to the outer peripheral wrap 21B. The space between 24 and the tooth bottom 25 can be sealed.
Note that the outer peripheral coating 28 may be provided at the base position of the step portion 31 </ b> C where the tip seal 22 is not provided in the inner peripheral wrap 31 </ b> A of the orbiting scroll 30.

In the second embodiment, the height of the wraps 21 and 31 has changed in one place in the circumferential direction, but the height of each of the wraps 21 and 31 is at two or more places from the outermost circumference to the innermost circumference. You may change so that it may become low gradually.
Hereinafter, the wrap 21 of the wraps 21 and 31 will be described as an example.
It is assumed that the height of the wrap 21 is changed at two locations, and the wrap 21 is divided into an outer wrap 21B, an intermediate wrap, and an inner wrap 21A according to the height. Even in that case, the outer peripheral coating 27 is provided over the region where the gap between the tooth tip 24 and the tooth bottom 25 can be sufficiently sealed only by the outer peripheral coating 27 even if the elongation amount varies depending on the operating conditions. A chip seal 22 may be provided in the region. For example, when the boundary B between the outer peripheral region R1 where the outer peripheral coating 27 is provided and the inner peripheral region R2 where the tip seal 22 is provided is placed between the outer peripheral wrap 21B and the intermediate wrap, the tooth tip 24 of the outer peripheral wrap 21B has an outer periphery. Only the coating 27 is provided, and the tip seals 22 can be provided alone or together with the inner coating 23 on the tooth tips 24 of the intermediate wrap and inner wrap 21A.

In each of the embodiments described above, both the fixed scroll 20 and the orbiting scroll 30 are provided with the outer peripheral coating 27 on the outer peripheral side and the tip seal 22 on the inner peripheral side. In only one of them, it is allowed to provide the outer peripheral coating 27 on the outer peripheral side and the chip seal 22 on the inner peripheral side.
For example, in the case where the gap between the tooth tip 24 of the orbiting scroll 30 and the tooth bottom 25 of the fixed scroll 20 that is opposed to the tooth scroll 25 must be wide, In addition, the outer peripheral coating 27 is provided on the outer peripheral side and the tip seal 22 is provided on the inner peripheral side. In the fixed scroll 20, the tip seal 22 is provided alone or together with the inner peripheral coating 23 on the inner peripheral side and the outer peripheral side. Can do.
As a case where there is a large variation in the gap between the tooth tip 24 of the orbiting scroll 30 and the tooth bottom 25 of the fixed scroll 20 that is opposed, for example, the pairing of the fixed scroll 20 and the orbiting scroll 30 may not be performed. . Pairing refers to an operation of grouping the produced scrolls 20 and 30 and making a pair of the scrolls 20 and 30 having the same height. When the pairing is performed, variation in the gap between the tooth tip and the tooth bottom of the fixed scroll 20 and the orbiting scroll 30 can be reduced, but the pairing is omitted and the fixed scroll 20 is supported. By inserting a thin plate between the upper bearing 19 </ b> A and the upper bearing 19 </ b> A, only the clearance adjustment for the tooth tip 24 of the fixed scroll 20 may be performed. In that case, since the clearance adjustment is not performed for the tooth tip 24 of the orbiting scroll 30, the variation in the clearance between the tooth tip 24 of the orbiting scroll 30 and the bottom 25 of the fixed scroll 20 is large. . In such a case, if the outer peripheral coating 27 is provided on only one of the fixed scroll 20 and the orbiting scroll 30, the tooth tip 24 of the orbiting scroll 30 having a large gap with the tooth bottom 25 of the fixed scroll 20 is provided. In contrast, the outer peripheral coating 27 may be provided preferentially.

In addition to the above, as long as the gist of the present invention is not deviated, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.
The scroll compressor of the present invention is not limited to the one using the rotational force of the motor as power, and may be one using the driving force transmitted from the engine to the shaft via the belt.
Moreover, the scroll compressor of this invention does not choose the working fluid which is compression object, such as a refrigerant | coolant and air.

10, 10 _3D scroll compressor 11 Motor 12 Stator 13 Rotor 14 Housing 15 Shaft 16 Suction pipe 17 Discharge pipe 18 Compression chamber 19A Upper bearing 19B Lower bearing 20 Fixed scroll 20A Inner peripheral bottom 20B Outer peripheral bottom 20C Stepped wall 21 Lap 21A Inner peripheral Wrap 21B Outer peripheral wrap 21C Stepped portion 21S Side 22 Tip seal 23 Inner peripheral abradable coating 24 Tooth tip 24A Tip surface 25 Tooth bottom 26 Seal groove 27 Outer peripheral abradable coating (outer peripheral coating)
28 peripheral coating 30 orbiting scroll 30C step wall 31 lap 31C step 31S side surface 34 boss 35 thrust plate 100 tip seal 101 tooth tip 102 tooth bottom 103 leakage path 104 side surface 105 side surface 106 seal groove 107 abradable coating 108 back pressure chamber 151 Eccentric pin 200 Fixed end plate 201 Discharge port 210 Suction port 211 Outermost circumference 212 Innermost circumference 300 Turning end plate 310 Suction port 311 Outermost circumference 312 Innermost circumference B Boundary C1 Clearance Cr1 Clearance G Gap P Contact point H1, H2 Height R1 Outer peripheral region R2 Inner peripheral region S1 Gap S2 Space S3 Gap S4 Gap Sp Gap Sp2 Gap

Claims (5)

A scroll compressor having a fixed scroll and a turning scroll,
The wraps of the fixed scroll and the orbiting scroll are meshed with each other in a state of facing the other end plate,
The tooth tip of the wrap on the outer peripheral side of at least one of the fixed scroll and the orbiting scroll is provided with an outer peripheral coating that wears away by contact with the tooth bottom of the counterpart end plate,
In each of the fixed scroll and the orbiting scroll, a tip seal is provided between the tooth bottom in the region where the outer peripheral coating is not provided, and the tooth bottom.
A scroll compressor characterized by that. The boundary between the inner peripheral side and the outer peripheral side in each of the fixed scroll and the orbiting scroll is:
Located at a rotation angle of 2.5π or less from the outermost circumference of the wrap to the inner circumference side,
The scroll compressor according to claim 1. The boundary is
Located at a rotation angle of 1.0π or more from the outermost periphery to the inner periphery of the wrap,
The scroll compressor according to claim 2. In the tooth tip of the region where the outer peripheral coating is not provided,
In addition to the tip seal,
A coating is provided that wears away upon contact with the root;
The scroll compressor as described in any one of Claim 1 to 3. Both the wraps of the fixed scroll and the orbiting scroll are lowered in height from the outer peripheral side to the inner peripheral side through the step portion,
A stepped wall that rises following the stepped portion of the lap on the opposite side is formed on any of the end plates of the fixed scroll and the orbiting scroll,
The boundary between the inner peripheral side and the outer peripheral side in each of the fixed scroll and the orbiting scroll is:
In the position of the step,
The scroll compressor as described in any one of Claim 1 to 4.

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