JP2007162622A - Scroll type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll type fluid machine in which the sealability of a pressure chamber is secured by a simple structure and having excellent volume efficiency and compression efficiency. <P>SOLUTION: This scroll type fluid machine comprises fixed and movable scrolls composed of end plates 8a, 10a and swirl walls 8b, 10b formed integrally with the end plates 8a, 10a, the grooves 18 opened in the leading end faces 17 of the swirl walls 8b, 10b of at least one of the scrolls, and swirl-like tip seals 16 disposed in the grooves 18 and having slidable contact surfaces 20 in slidable contact with the end plates 10a, 8a of the other scroll. The tip seal 16 has side faces 24 continued at an acute angle to the slidable contact surface. The groove 18 has side wall surfaces 26 continued at an obtuse angle to the end faces 17 of the swirl walls 8b, 10b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a scroll type fluid machine.

  For example, a scroll type fluid machine used as a fluid machine in a refrigeration circuit of an automotive air conditioning system includes a scroll unit, and the scroll unit includes a fixed scroll and a movable scroll. These fixed and movable scrolls each have an end plate and a spiral wall integrally formed on the inner surface of the end plate, and are airtight between each other via a tip seal disposed in a groove at the end of the spiral wall. It arrange | positions in the state which the mutually spiral wall mesh | engaged so that a pressure chamber may be formed. The movable scroll orbits with respect to the fixed scroll by receiving power through the orbiting unit, and the volume and position of the pressure chamber change with the orbiting movement, so that the refrigerant compression process in the pressure chamber (For example, Patent Document 1).

In general, the chip seal has a rectangular cross-sectional shape, and the groove in which the chip seal is disposed is constituted by two side wall surfaces perpendicular to the tip surface of the spiral wall and a concave bottom surface.
JP-A-8-261171

In order to increase volumetric efficiency and compression efficiency in a scroll type fluid machine, it is only necessary to improve the sealing performance of the pressure chamber and suppress leakage of the working fluid from the pressure chamber (internal leakage). In particular, in a scroll type fluid machine that compresses CO ₂ as a refrigerant, the volume of the pressure chamber is small and the pressure of the refrigerant in the pressure chamber is high compared to the case of using a conventional chlorofluorocarbon refrigerant. Therefore, volume efficiency and compression efficiency are remarkably improved by increasing the sealing performance of the pressure chamber.

  As specific means for enhancing the sealing performance of the pressure chamber, it is effective to increase the width of the chip seal and increase the contact area between the sealing surface of the chip seal and the end plate. When the width of the chip seal having a rectangular cross-sectional shape is increased, the width of the groove must be increased while ensuring the strength of the side wall portion of the groove, and the thickness of the spiral wall needs to be increased. As a result, when the width of the chip seal whose cross-sectional shape is rectangular is increased, the weight and size of the fluid machine are increased.

  The present invention has been made on the basis of the above-mentioned circumstances, and an object of the present invention is to provide a scroll type fluid machine that has a simple structure and ensures the sealing performance of the pressure chamber and has excellent volumetric efficiency and compression efficiency. There is to do.

  In order to achieve the above object, according to the present invention, a fixed and movable scroll including an end plate and a spiral wall integral with the end plate, and a distal end surface of the spiral wall in at least one of the scrolls. In a scroll type fluid machine, comprising: an open groove; and a spiral chip seal that is disposed in the groove and has a sliding contact surface that is in sliding contact with the end plate of the other scroll, the tip seal includes the sliding seal. There is provided a scroll type fluid machine having a side surface continuous with an acute angle with respect to a contact surface, and the groove has a side wall surface connected with an obtuse angle with respect to a tip surface of the spiral wall. .

As a preferred embodiment, the groove has an isosceles trapezoidal shape when viewed in a cross-sectional view (claim 2).
As a preferred embodiment, the scroll type fluid machine compresses CO ₂ as a working fluid.

In the scroll type fluid machine according to claim 1 of the present invention, the width of the sliding contact surface is increased because the tip seal has a side surface continuous with an acute angle with respect to the sliding contact surface. As a result, the sealing performance of the pressure chamber is improved, and the volume efficiency and the compression efficiency are also improved.
On the other hand, in this scroll type fluid machine, since the groove has a side wall surface connected at an obtuse angle with respect to the front end surface of the spiral wall, not only the tip seal is reliably supported by the groove, but also the root portion of the side wall surface. Strength is secured. As a result, the sealing performance of the pressure chamber is improved without increasing the thickness of the spiral wall.

In the scroll type fluid machine according to the second aspect, the groove is easily formed at the tip of the spiral wall by forming an isosceles trapezoid when viewed in a cross-sectional view. As a result, the sealing performance of the pressure chamber is improved without increasing the cost.
In the scroll type fluid machine according to the third aspect, since the sealing performance of the pressure chamber is improved, CO ₂ as the working fluid is compressed with excellent volumetric efficiency and compression efficiency.

FIG. 1 shows a schematic configuration of a scroll type fluid machine of one embodiment.
The fluid machine includes a housing 2, and although not shown, the housing 2 is formed with a suction port for introducing a working fluid from the outside and a discharge port for discharging the working fluid to the outside. These suction port and discharge port open to a suction chamber 4 and a discharge chamber 6 defined inside the housing 2, respectively.

A metal fixed scroll 8 and a movable scroll 10 are arranged inside the housing 2. Each of these fixed and movable scrolls 8, 10 has end plates 8a, 10a and spiral walls 8b, 10b integral with the end plates 8a, 10a.
The fixed and movable scrolls 8 and 10 are arranged so as to mesh with each other so as to form a pressure chamber 12 between them. Under this arrangement, the movable scroll 10 can swing with respect to the fixed scroll 8. In conjunction with this swirl movement, the pressure chamber 12 moves along the spiral walls 8b, 10b from the radially outer side of the end plates 8a, 10a toward the center, and the pressure chamber 12 moves in the radial direction of the end plates 8a, 10a. As the position approaches the center, the volume of the pressure chamber 12 decreases.

  Here, the suction chamber 4 described above is partitioned around the movable scroll 10, and when the pressure chamber 12 is positioned on the radially outer side of the end plate 10 a, the working fluid in the suction chamber 4 is introduced into the pressure chamber 12. The The discharge chamber 6 and the pressure chamber 12 described above are partitioned by the end plate 8a of the fixed scroll 8. When the pressure chamber 12 is positioned at the center in the radial direction of the end plate 8a, the end plate 8a. Communicates with the discharge chamber 6 through a discharge hole 14 provided substantially at the center. Although not shown, the discharge hole 14 is opened and closed by a reed valve.

In order to ensure the sealing performance of the pressure chamber 12, resin tip seals 16 are provided at the ends of the spiral walls 8b and 10b, respectively. The spiral walls 8 b and 10 b of the fixed and movable scrolls 8 and 10 are in sliding contact with the end plates 10 a and 8 a of the other scrolls 10 and 8 through the tip seals 16.
Hereinafter, the tip seal 16 will be described in detail. Since the configuration of the tip seal 16 provided on the fixed and movable scrolls 8 and 10 is the same, the tip seal 16 on the movable scroll 10 side will be described as an example.

The tip seal 16 extends spirally along the spiral wall 10b as shown in FIG. 2, and extends from the vicinity of the inner end of the spiral wall 10b to the front of the outer end in the spiral direction.
FIG. 3 is an enlarged view of the vicinity of the tip seal 16 of FIG. 1, and the tip seal 16 is fitted in a spiral groove 18 opened in the distal end surface 17 of the spiral wall 10b. As seen in this cross-sectional view, the tip seal 16 has an isosceles trapezoidal shape, and a sliding contact surface 20 as a sealing surface that comes in sliding contact with the end plate 8 a of the fixed scroll 8 and a lower surface 22 that comes into contact with the bottom surface of the groove 18. Are parallel to each other.

The width Wt of the slidable contact surface 20 is larger than the width Wb of the lower surface 22 (Wt> Wb), and the side surface 24 of the chip seal 16 is connected to the side edge of the slidable contact surface 20 at an acute angle, while the lower surface 22 side. It runs at an obtuse angle with respect to the edge.
In addition, as shown in FIG. 3, the groove 18 also has an isosceles trapezoidal shape, and the side wall surface 26 of the groove 18 is connected at an obtuse angle with respect to the tip surface 17 of the spiral wall 8b. The slope of the side wall surface 26 is substantially equal to the slope of the side surface 24 so that the side wall surface 26 contacts the side surface 24 of the tip seal 16.

The thickness T of the tip seal 16 and the depth D of the groove 18 are constant in the spiral direction, and the thickness T is slightly larger than the depth D. For this reason, the sliding contact surface 20 of the chip seal 16 is in sliding contact with the end plate 8a of the fixed scroll 8 over the entire area. Further, the opening width Wg of the groove 18 is slightly smaller than the width Wt of the sliding contact surface 20.
Referring again to FIG. 1, the movable scroll 10 is connected to one end portion of the drive shaft 30 in order to make the above-described movable scroll 10 turn.

More specifically, an eccentric bush 32 is fixed to one end portion of the drive shaft 30, and the eccentric bush 32 can rotate integrally with the drive shaft 30. The eccentric bush 32 is surrounded by a boss integrally provided on the outer surface of the end plate 10a, and a bearing 34 is interposed between the eccentric bush 32 and the boss.
The other end of the drive shaft 30 is connected to, for example, a driven unit of an electromagnetic clutch 36 attached to a fluid machine, and power from the outside is intermittently transmitted to the drive shaft 30 via the electromagnetic clutch 36.

Hereinafter, the operation of the above-described scroll type fluid machine will be described by taking as an example a case where a refrigerant composed of CO ₂ is compressed as the working fluid.
When the drive shaft 30 is rotationally driven, the movable scroll 10 orbits with respect to the fixed scroll 8 via the eccentric bush 32 as the drive shaft 30 rotates. By this orbiting motion, the fixed and movable scrolls 8 and 10 execute the following series of processes.

  First, the fixed and movable scrolls 8 and 10 suck the low-pressure gas refrigerant into the pressure chamber 12 located radially outside through the suction port and the suction chamber 4 (suction process). Thereafter, the pressure chamber 12 that has sucked the refrigerant moves toward the center of the end plates 8a and 10a along the spiral walls 8b and 10b. The refrigerant is compressed (compression process). The refrigerant compressed in the pressure chamber 12 is discharged to the outside through the discharge hole 14, the discharge chamber 6, and the discharge port when the pressure chamber 12 communicates with the discharge hole 14 at the center of the end plates 8a and 10a. (Discharge process).

  In the scroll type fluid machine described above, the width Wt of the sliding contact surface 20 of the chip seal 16 is larger than the width Wb of the lower surface 22, and the end plates 8a and 10a and the sliding contact surface 20 are equal to the difference (Wt−Wb). The contact area between the two has increased compared to the prior art. In other words, the gaps (side gaps) between the end plates 8a, 10a immediately next to the tip seal 16 and the tip surfaces 17 of the spiral walls 8b, 10b are reduced. As a result, in this fluid machine, the sealing performance of the pressure chamber 12 is improved, and the volume efficiency and the compression efficiency are also improved.

Further, in the chip seal 16, since the cross-sectional shape is an isosceles trapezoidal shape, stress concentration is prevented and the chip seal 16 is prevented from being broken.
On the other hand, in this fluid machine, the side wall surface 26 of the groove 18 also has a slope so as to contact the side surface 24 of the chip seal 16, and the chip seal 16 is reliably supported by the groove 18. In addition, since the side wall surface 26 has a gradient, a sufficient thickness of the side wall of the groove 18 is ensured near the base of the side wall surface 26 and stress concentration near the base of the side wall surface 26 is alleviated. As a result, in this fluid machine, the strength of the side wall of the groove 18 is ensured without increasing the thickness of the spiral walls 8b and 10b.

Thus, in this fluid machine, the sealing performance of the pressure chamber 12 is improved while ensuring the strength of the side wall of the groove 18, so that even if applied to compress CO ₂ as a refrigerant, it is excellent. It operates for a long time with high volumetric efficiency and compression efficiency.
That is, when compressing CO ₂ as a refrigerant, the pressure in the pressure chamber 12 is higher than when compressing R134a or the like. However, in this fluid machine, the side wall of the groove 18 and the tip seal 16 are broken. There is nothing. As a result, the fluid machine is ensured in durability and operates stably over a long period of time.

In addition, when compressing CO ₂ as a refrigerant, CO ₂ not only has a high pressure, but also has a small molecular weight and is likely to leak from the pressure chamber 12 in the compression process. From balance between its upper, in this case, the refrigerating capacity, the volume of the pressure chamber 12 is set to about 1/6 as compared with the case of compressing R134a, etc., the CO ₂ leaks little from the pressure chamber 12, the fluid The volumetric efficiency and compression efficiency of the machine are greatly deteriorated. However, even in such a case, in this fluid machine, leakage of CO ₂ from the pressure chamber 12 is reliably prevented by the tip seal 16. As a result of this, the fluid machine operates with excellent volumetric efficiency and compression efficiency.

The present invention is not limited to the above-described embodiment, and various modifications are possible. The fluid machine is also applied to a working fluid other than CO ₂ .
In one embodiment, both side surfaces 24 of the tip seal 16 are connected to the sliding contact surface 20 at the same angle, but both side surfaces may be connected to the sliding contact surface 20 at different angles. Furthermore, it is only necessary that at least one of the side surfaces of the chip seal is continuous at an acute angle with respect to the side edge of the sliding contact surface 20.

Similarly, the side wall surface of the groove 18 may be continuous with the front end surface 17 at different angles. Furthermore, it is sufficient that at least one of the side wall surfaces is continuous with an acute angle with respect to the side edge of the tip surface 17. However, the isosceles trapezoidal groove 18 is preferable because it is easily formed in the distal end surface 17 in a cross-sectional view.
Further, the corner portion of the tip seal 16 may be rounded, and it is sufficient that the side surface thereof is substantially continuous with the side edge of the sliding contact surface 20. Similarly, the corner portion of the groove 18 may be rounded, and the side wall surface only needs to be substantially obtuse with respect to the opening edge of the distal end surface 17.

In the fluid machine of one embodiment, the tip seals 16 of both the fixed scroll 8 and the movable scroll 10 have a trapezoidal shape as viewed in a cross-sectional view, but the tip seals of at least one scroll are cross-sectional views. If it sees, trapezoidal shape should just be made.
In the fluid machine of one embodiment, the chip seal 16 is made of one of polyphenylene sulfide resin (PPS resin), polyether ether ketone resin (PEEK resin), and polyimide resin (PI resin). preferable. This is because these resins are excellent in wear resistance and the durability of the fluid machine is further improved.

4 and 5 show a modified tip seal 40 and a tip seal 42, and the thickness T of the tip seal may be equal to or less than the depth D of the groove 18. FIG. That is, the slidable contact surface 20 only needs to be positioned in the vicinity of the distal end surface 17, and the slidable contact surface 20 is in a state where the tip seals 40 and 42 are slightly lifted from the bottom surface of the groove 18 during operation of the fluid machine. It is in sliding contact with the plates 8a and 10a.
FIG. 6 also shows a modified tip seal 44, where the slope of the side surface 24 of the tip seal 44 may not be the same as the slope of the sidewall surface 26 of the groove 18. In this case, by using the fluid machine, the tip seal 44 is compressed in the thickness direction, so that the gradient of the side surface 24 gradually approaches the gradient of the side wall surface 26.

  Finally, it goes without saying that the fluid machine of the present invention may be used as an expander, and the working fluid is not particularly limited.

It is a longitudinal cross-sectional view which shows the outline of the scroll type fluid machine of one Example. FIG. 2 is a plan view of a movable scroll and a chip seal applied to the fluid machine of FIG. 1. FIG. 2 is an enlarged view of the vicinity of a chip seal in FIG. 1. It is a cross-sectional view which shows the chip seal of the modification arrange | positioned at the groove | channel. It is a cross-sectional view which shows the chip seal of the other modification arrange | positioned in the groove | channel. It is a cross-sectional view which shows the chip seal of the further another modification arrange | positioned at a groove | channel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 8 Fixed scroll 10 Movable scroll 8a, 10a End plate 8b, 10b Spiral wall 16 Tip seal 17 Front end surface of spiral wall 18 Groove 20 Sliding surface 24 Side surface 26 Side wall surface

Claims (3)

A fixed and movable scroll comprising an end plate and a spiral wall integral with the end plate;
A groove opened in a tip surface of the spiral wall in at least one of the scrolls;
In a scroll type fluid machine comprising a spiral tip seal having a sliding contact surface that is disposed in the groove and is in sliding contact with the end plate of the other scroll.
The tip seal has a side surface continuous with an acute angle with respect to the sliding contact surface,
The scroll type fluid machine according to claim 1, wherein the groove has a side wall surface connected at an obtuse angle with respect to a front end surface of the spiral wall.   The scroll fluid machine according to claim 1, wherein the groove has an isosceles trapezoidal shape when viewed in a cross-sectional view. The scroll type fluid machine according to claim 1, wherein CO ₂ is compressed as a working fluid.

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