Scroll compressor

A scroll compressor is provided that can cool a fixed scroll and an orbiting scroll effectively via cooling fins. A scroll compressor includes: a fixed scroll, an orbiting scroll that performs orbiting motion with respect to the fixed scroll and is combined with the fixed scroll so as to form, with the fixed scroll, a compression space to compress fluid; cooling fins that are provided on the back of the fixed scroll; and cooling fins that are provided on the back of the orbiting scroll. The cooling fins and the cooling fins are taller in a central portion than in the circumference of the central portion.

RELATED APPLICATIONS

The present application is a National Phase entry of International Application No. PCT/JP2015/000011, filed Jan. 5, 2015, which claims the benefit of priority from Japanese Patent Application No. 2014-027427, filed Feb. 17, 2014.

TECHNICAL FIELD

The present invention relates to an improvement of a cooling fin of a scroll compressor.

BACKGROUND ART

A scroll compressor includes a fixed scroll and an orbiting scroll. The fixed scroll and the orbiting scroll are both scrolls each including a disk-shaped end plate on one-face side of which a spiral wrap is provided. Such fixed scroll and orbiting scroll are made to face each other with their wraps engaged with each other, and the orbiting scroll is caused to perform orbiting motion with respect to the fixed scroll. Then, by reducing the volume of a compression space formed between both the scrolls with orbiting of the orbiting scroll, fluid in the space is compressed.

There is known a scroll compressor in which a large number of cooling fins are provided on the back of each of an end plate of a fixed scroll and an end plate of an orbiting scroll to dissipate heat of compression with the compression of fluid and frictional heat with rotations of components (e.g., Patent Literature 1 to Patent Literature 3). In particular, air cooling via cooling fins is employed in oil-free scroll compressors in which refrigerating machine oil mainly for lubrication is not used.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

A scroll compressor suctions fluid from the outer circumference side of scrolls, the fluid being to be compressed, and compression is performed gradually toward the center thereof. The compressed fluid is discharged from a port provided in the central portion of the fixed scroll to the outside. Since the temperature of the fluid rises with an increase in the degree of compression, the scrolls are to be exposed to a higher temperature as approaching to the central portion.

Thus, the present invention has an objective to provide a scroll compressor that makes it possible to cool a central portion of a scroll effectively.

Solution to Problem

A scroll compressor of the present invention that is made based on such an objective includes: a fixed scroll that includes a front on which a fixed-side wrap portion is provided, and a back on which a fixed-side cooling fin portion is provided; and an orbiting scroll that is combined with the fixed scroll so as to form, with the fixed scroll, a compression space to compress fluid, and includes a front on which an orbiting-side wrap portion is provided and a back on which an orbiting-side cooling fin portion is provided, wherein (one or both of) the fixed-side cooling fin portion comprising a plurality of fins and the orbiting-side cooling fin portion comprising a plurality of fins are each configured such that fins positioned in a central portion in a radial direction are taller than fins positioned in an outer circumferential portion around the central portion.

According to the scroll compressor of the present invention, the fins positioned in the central portion are taller than the fins positioned in the outer circumferential portion, and thus a heat-transfer area is large, which makes it possible to cool the central portion of the scrolls effectively.

In the scroll compressor of the present invention, one or both of the fixed-side cooling fin portion and the orbiting-side cooling fin portion can be configured to be taller in a stepwise manner or continuously as approaching to the central portion.

When the fixed-side cooling fin portion and the orbiting-side cooling fin portion are made to be taller continuously, it is possible to obtain cooling power corresponding to the degree of compression of the fluid, which has an advantage in the improvement of cooling power. In contrast, making the fixed-side cooling fin portion and the orbiting-side cooling fin portion taller in a stepwise manner is easy for manufacture including setting the heights.

In the scroll compressor of the present invention, it is preferable that one or both of the fixed-side cooling fin portion and the orbiting-side cooling fin portion are each configured such that front ends thereof are aligned with a single plane.

In such a manner, it is possible to avoid occupying an unnecessary space therearound, and for example, for a portion of a housing or the like corresponding to cooling fins, having a flat shape suffices.

To align the front ends of one or both of the fixed-side cooling fin portion and the orbiting-side cooling fin portion with a single plane, the wall thickness of (one or both of) a fixed-side end plate on which the fixed-side cooling fin portion is provided and an orbiting-side end plate on which the orbiting-side cooling fin portion is provided may be made smaller in the central portion than in an outer circumferential portion around the central portion.

Scroll compressors with this configuration include what is called a 3D scroll compressor, in which each a fixed-side wrap portion and an orbiting-side wrap portion is provided with level differences in an addendum and a basal portion so as to be taller in the central portion than in the outer circumferential portion.

Advantageous Effect of Invention

According to the scroll compressor of the present invention, fins positioned in a central portion are made taller than fins positioned in an outer circumferential portion, and thus a heat-transfer area is large, which makes it possible to cool the central portion of a scroll effectively.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail based on embodiments illustrated in the accompanying drawings.

First Embodiment

A scroll compressor1in the present embodiment includes, as illustrated inFIG. 1andFIG. 2, a housing10that forms an outer shell of the scroll compressor1, a fixed scroll20that is fixed to the housing10, and an orbiting scroll30that is housed in the housing10in such a manner as to be able to orbit, as main components. These main components are formed of a metallic material such as an aluminum-based alloy, and an iron-based alloy.

The scroll compressor1is a scroll compressor of what is called a 3D scroll (Registered mark) that can provide a high compression ratio by employing a 3D compressing mechanism that compresses fluid not only in a circumferential direction but also in a height direction.

The housing10is, as illustrated inFIG. 1, a hermetically sealed container that is formed by a first housing10aand a second housing10b.

The first housing10ais fixed to the fixed scroll20and houses therein cooling fins24of the fixed scroll20. The first housing10aincludes a discharge port12that discharges, toward the outside, compressed fluid discharged from a discharge port21eof the fixed scroll20.

The second housing10bhouses and retains, in a housing chamber11b, the orbiting scroll30, self-rotation preventing mechanisms40, and a driving shaft50. The second housing10bincludes, in the housing chamber11b, a housing chamber11cthat houses second elements45of the self-rotation preventing mechanisms40, and a housing chamber11dthat houses the driving shaft50and a main bearing54.

The fixed scroll20includes, as illustrated inFIG. 1, an end plate21that is formed into a substantially disk shape, a wrap22that has a spiral shape and is provided on one-face side of the end plate21, the cooling fins24that are provided on the other-face side of the end plate21, and an outer circumferential wall26that surrounds the outermost circumference of the fixed scroll20. For example, the fixed scroll20is cast in an aluminum alloy to be integrally formed into. The outer circumferential wall26is provided with a suction port27that suctions fluid to be subjected to compression. In addition, the outer circumferential wall26is exposed to the outside, constituting part of the housing10. Note that, in the fixed scroll20, a side on which the wrap22is provided is assumed to be front, and a side on which the cooling fins24are provided is assumed to be back.

In order to make the height of the wrap22on its inner circumference side lower than on its outer circumference side, the scroll compressor1of 3D type is provided on the end plate21with a lower stage portion21aand a higher step portion21b, and the wrap22formed on the lower stage portion21ais made tall, and the wrap22formed on the higher step portion21bis made short. Note that a level difference in the boundary between the lower stage portion21aand the higher step portion21balso appears on the back of the end plate21, where a concave groove21cis formed that surrounds the discharge port12and extends back toward the front.

The wrap22is provided at its front end with a tip seal23that has self-lubricating and is brought into contact with an end plate31of the orbiting scroll30to make a sealing.

The end plate21is formed with a discharge port21ethat penetrates both sides of the end plate21, and fluid compressed by the fixed scroll20and the orbiting scroll30is discharged to the outside from the discharge port12, through the discharge port21e.

The end plate21is provided on the back with the plurality of cooling fins24, namely a fixed-side cooling fin portion, that cools the fixed scroll20by allowing ambient air flowing in from an opening (not illustrated) formed in the housing10to pass through the cooling fins24. Although, in the present embodiment, the plurality of plate-shaped cooling fins24are formed turning in the same direction, the plurality of cooling fins24can be provided, for example, radially from the center of the end plate21. This is also true for the orbiting scroll30.

The cooling fins24has different heights between the higher step portion21band the lower stage portion21asurrounding the higher step portion21b, and the cooling fins24provided in the higher step portion21bcorresponding to the center are tall.

The orbiting scroll30includes, as illustrated inFIG. 1, the end plate31that is formed into a substantial disk shape, a wrap32that has a spiral shape and is provided on one-face side of the end plate31, and cooling fins34that are provided on the other-face side of the end plate31. For example, the orbiting scroll30is cast in an aluminum alloy to be integrally formed into. Note that, in the orbiting scroll30, a side on which the wrap32is provided is assumed to be front, and a side on which the cooling fins34are provided is assumed to be back.

The wrap32of the orbiting scroll30corresponds to the wrap22of the fixed scroll20, and is formed so as to have a height that is smaller on its inner circumference side than on its outer circumference side. The end plate31is provided with a lower stage portion31aand a higher step portion31b, and the wrap32formed on the lower stage portion31ais made tall, and the wrap32formed on the higher step portion31bis made short. Note that a level difference in the boundary between the lower stage portion31aand the higher step portion31balso appears on the back of the end plate31, where a concave groove31cextends back toward the front.

The wrap32is provided at its front end with a tip seal33that has self-lubricating and is brought into contact with the front side of the end plate21of the fixed scroll20to seal a compression chamber.

The end plate31is provided on the back with the plurality of cooling fins34, namely an orbiting-side cooling fin portion, that cools the orbiting scroll30by allowing ambient air flowing in from the opening (not illustrated) formed in the housing10to pass the cooling fins34. The plurality of plate-shaped cooling fins34are formed turning in the same direction.

As with the cooling fins24, the cooling fins34has different heights between the higher step portion31band the lower stage portion31asurrounding the higher step portion31b, and the cooling fins34provided in the higher step portion31bcorresponding to the center are tall.

The orbiting scroll30includes a bearing plate35that is fixed to the front end side of the cooling fins34.

The bearing plate35includes a boss36that houses and fixes a bearing37in its central portion. The bearing37retained by the boss36supports an eccentric shaft53of the driving shaft50.

In addition, the bearing plate35includes three bosses38that house first elements41of the self-rotation preventing mechanisms40, in a circumferential direction at regular intervals, as illustrated inFIG. 2.

The self-rotation preventing mechanisms40are self-rotation preventing mechanisms of a pin crank type and each includes the first element41and the second elements45. The scroll compressor1includes three self-rotation preventing mechanisms40that correspond to the three bosses38.

The first element41includes a bearing42. The bearing42is formed by, for example, a ball bearing that includes an inner ring, an outer ring, and spherical rolling elements provided between the inner ring and the outer ring. The inner ring of the bearing42is fitted with a crank pin (first pin)43that constituted the first element41together with the bearing42. The first element41is housed in the boss38of the bearing plate35, and this boss38functions as a bearing housing of the bearing42.

The second element45has a configuration similar to that of the first element41including two bearings46, and a crank pin (second pin)47that is inserted into the inner ring of the bearing46. The second elements45are housed and retained in the housing chamber11cof the housing10.

The crank pin43of the first elements41and the crank pin47of the second element45are integrally connected to each other via an eccentric shaft44, and the crank pin43, the crank pin47, and the eccentric shaft44form an integrated crankshaft.

The boss38includes, as illustrated inFIG. 2, an inner wall38a, which restricts the amount and direction of the displacement of the bearing42. An opening of this inner wall38ais different from a perfect circle and forms an elliptical shape that has a major axis in a radial direction of the bearing plate35, and a minor axis in a circumferential direction of the bearing plate35. That is, the boss38and the bearing42have such an anisotropy that makes an allowed amount of displacement of the bearing42(crank pin47) large in the radial direction and small in the circumferential direction. Therefore, even if the orbiting scroll30thermally expands, the amount of displacement of the bearing42in the circumferential direction can be suppressed to be small while the displacement of the bearing42in the radial direction is absorbed. Therefore, it is possible to prevent the orbiting scroll30from twisting with respect to the fixed scroll20.

The driving shaft50transmits rotary driving force of a driving source such as an electric motor, which is not illustrated, to the orbiting scroll30.

As illustrated inFIG. 1, the driving shaft50includes, on its one-end side, a connection end51that is connected to the driving source, and at the other end, the eccentric shaft53that is retained by the bearing37. The bearing37is retained by the bearing plate35.

The driving shaft50is rotatably supported by the housing10with two bearings: the main bearing54and a sub bearing55. The main bearing54supports the driving shaft50in the vicinity of the eccentric shaft53, and the sub bearing55supports the driving shaft50in the vicinity of the connection end51.

Next, the operation of the scroll compressor1having the above configuration is as follows.

When driving shaft50rotates with the rotation of a driving source, which is not illustrated, the orbiting scroll30starts orbiting motion. Then, fluid suctioned from the suction port27is compressed in a crescent-shaped compression space that is formed by the wrap22and the wrap32, and discharged from the discharge port12provided in the central portion.

While the scroll compressor1operates, the self-rotation preventing mechanisms40prevent the orbiting scroll30from performing self-rotation.

In addition, while the scroll compressor1operations, intake ambient air passes through the cooling fins24provided on the back of the fixed scroll20and cooling fins34provided on the back of the orbiting scroll30, whereby the fixed scroll20and the orbiting scroll30are cooled.

[Advantageous Effects of Scroll Compressor1]

Next, advantageous effects of the scroll compressor1will be described.

When fluid is compressed, the temperature thereof rises, and thus while the scroll compressor1is driven, the fixed scroll20and the orbiting scroll30are exposed to a high temperature to thermally expand. When the thermal expansion exceeds tolerance, there is the risk that an addendum of one of the scrolls is brought contact with a dedendum of the other scroll, inhibiting the orbiting scroll30from performing smooth orbiting motion.

However, since the fixed scroll20and the orbiting scroll30are cooled via the cooling fins24and the cooling fins34, it is possible to suppress the thermal expansion. In particular, the scroll compressor1has a high cooling capacity because the cooling fins24and the cooling fins34respectively provided in the fixed scroll20and the orbiting scroll30, the temperatures of which become high, are taller in the central portion than in a peripheral portion.

Since the scroll compressor1is a 3D-type scroll compressor, the back of fixed scroll20and the back of the orbiting scroll30are both recessed in the higher step portions21band31bpositioned in their centers. In the present embodiment, the recesses are utilized to make the cooling fins24and the cooling fins34in the relevant portions tall. Meanwhile, in the central portion and an outer circumferential portion therearound, the front ends of the cooling fins24are aligned with a single plane. This is also true for the cooling fins34. Therefore, the scroll compressor1can be configured in such a manner as to align the positions of the front ends of each of the cooling fins24and34with one another from the center to the outer circumference while making the cooling fins24and34taller in the central portion. This indicates that, it is possible to avoid occupying an unnecessary space around the cooling fins24and34, the unnecessary space being generated when the cooling fins24and34positioned in the central portion project so as to make the cooling fins24and34tall, and indicates that for example, for a portion of the first housing10acorresponding to the cooling fins24, having a flat shape suffice.

Second Embodiment

Although the first embodiment is about the 3D-type scroll compressor1, the present invention is applicable to scroll compressors of types other than the 3D type, as illustrated inFIGS. 3A, 3B, 4A and 4B.

FIG. 3AandFIG. 3Billustrates examples in which cooling fins24and cooling fins34provided in the fixed scroll20and the orbiting scroll30including the backs of the end plate21and the end plate31that are both flat are formed to be taller in the central portion than in the outer circumference portion. Of the drawings,FIG. 3Aillustrates an example in which the cooling fins24and the cooling fins34are made tall in a stepwise manner, andFIG. 3Billustrates an example in which the cooling fins24and the cooling fins34are made tall continuously. Note that, as an example of the stepwise manner, here is illustrated an example of two stages including a higher step and a lower stage, but the number of stages can be three or more.

In the examples illustrated inFIG. 3AandFIG. 3B, positions of the front ends of each of the cooling fins24and the cooling fins34are uneven, but, as illustrated inFIG. 4AandFIG. 4B, the thicknesses of the end plate21and the end plate31can be reduced in a stepwise manner (FIG. 4A) or continuously (FIG. 4B) toward the central portion. By making, in such a manner, basal portions of the cooling fins24and the cooling fins34extend on the end plate21's side and the end plate31's side, it is possible to align the front ends of each of the cooling fins24and the cooling fins34with a single plane. With this configuration, it is possible to avoid occupying an unnecessary space which is generated when the cooling fins24and34positioned in the central portion project, and for example, for a portion of the first housing10acorresponding to the cooling fins24, having a flat shape suffices.

The preferred embodiments of the present invention have been described above, and the configurations described in the above embodiments may be selected or changed to the other configurations as appropriate, without departing from the gist and scope of the present invention.

For example, the embodiments described above have been made about the examples in which the heights of both of the cooling fins24of the fixed scroll20and the cooling fins34of the orbiting scroll30are made tall in the central portion, but the present invention allows for making only one of the fixed scroll20and the orbiting scroll30tall. In addition, the present invention is also applicable to the case where cooling fins are provided in only one of the fixed scroll20and the orbiting scroll30.

Furthermore, the embodiments described above improve the cooling power of the central portion by making the cooling fins24and the cooling fins34in the central portion tall, and it is possible to improve further the cooling power of the central portion by adjusting the densities of the provision of the cooling fins24and the cooling fins34, the plate thicknesses of the cooling fins24and the cooling fins34, and the like.

Besides, the scroll compressor1is merely an example, and the present invention is widely applicable to scroll compressors including cooling fins.