JP4868894B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor, and more particularly to a scroll compressor suitable for use in a gas engine driven heat pump.

This type of scroll compressor includes a compression unit having a movable scroll that performs a series of refrigerant suction, compression, and discharge processes in cooperation with the fixed scroll, and a compression chamber is formed by the fixed scroll and the movable scroll. Is done. Moreover, the scroll compressor is known to have a configuration capable of changing the discharge capacity (see, for example, Patent Documents 1 and 2).
Specifically, the compressor is provided with a refrigerant main path and a bypass path. In the former main path, the compressed refrigerant passes through the compression chamber and the discharge chamber from the low-pressure side path of the refrigeration circuit. To the high pressure side path. On the other hand, in the latter bypass path, the high-pressure side path is bypassed, and the low-pressure side path is passed through the compression chamber and bypass chamber and the variable throttle mechanism arranged outside, and the refrigerant being compressed is again low-pressure. Lead to the side path. When the load on the refrigeration circuit is large, the path is narrowed by the variable throttle mechanism to increase the discharge capacity. On the other hand, when the load on the refrigeration circuit is small, the variable throttling mechanism opens the path to reduce the discharge capacity.
Japanese Patent Laid-Open No. 2000-25769 JP 2001-355585 A

By the way, in the compression unit described above, the refrigerant containing the liquid may be sucked into the compression chamber from the low-pressure side path. When the refrigerant containing this liquid is compressed, the pressure in the compressor rapidly rises, which becomes a factor that hinders normal operation of the compressor.
However, in the above conventional technique, the refrigerant containing the liquid in the compression chamber is simply supplied to either the main path or the bypass path. That is, when supplied to the former main path, a high pressure due to liquid compression acts on the scroll, which causes a problem that the scroll is damaged. On the other hand, when supplied to the latter bypass path, there is a variable throttle mechanism on the way to the low-pressure path, so that depending on the throttle condition, the refrigerant containing liquid does not sufficiently flow into the bypass path, and the liquid compression is performed in the compression chamber. It is feared that it may be invited. As described above, the above-described conventional technique still has a problem regarding prevention of liquid compression.

  This invention is made | formed in view of such a subject, and it aims at providing the scroll compressor which can prevent liquid compression.

In order to achieve the above object, a scroll compressor according to claim 1 includes a front housing, a casing hermetically fitted to the front housing, a crankshaft rotatably supported in the front housing, and a casing. And a compression unit having a movable scroll that performs a series of processes of refrigerant suction, compression, and discharge in cooperation with the fixed scroll by being driven by the crankshaft and pivoting. The compression unit is fixed A compression chamber formed by a scroll and a movable scroll and compressing refrigerant sucked from the low-pressure side path of the refrigeration circuit, a discharge chamber for supplying high-pressure compressed refrigerant from the compression chamber to the high-pressure side path of the refrigeration circuit, and a high-pressure side path a bypass chamber connected by a bypass to outlet hole and a compression chamber and a low pressure side path and bypass A chamber and a discharge chamber communicating near the compression chamber than the outlet hole, is characterized by comprising a communication hole for discharging the refrigerant containing the compression chamber of the liquid through the bypass chamber to the discharge chamber.

In the invention described in claim 2, the communication hole is formed in the fixed scroll.
Furthermore, in the invention described in claim 3, the compression unit further includes a valve device that opens and closes the communication hole, and the valve device is opened when the pressure in the bypass chamber is higher than the pressure in the discharge chamber. It is said.

Therefore, according to the scroll compressor of the present invention, the bypass unit and the discharge chamber are connected to the compression unit closer to the compression chamber than the outlet hole, and the refrigerant containing the liquid in the compression chamber is connected to the compression unit. A communication hole for discharging to the discharge chamber is provided. Therefore, even if a refrigerant containing liquid is present in the compression chamber, the refrigerant is introduced into the main path directly from the compression chamber to the discharge chamber or the bypass path from the bypass chamber to the low-pressure side path through the outlet hole. Instead, the refrigerant reaches the discharge chamber via the communication hole from the bypass chamber, so that liquid compression of the refrigerant is prevented. As a result, an abnormally high pressure is not applied to the compression chamber, and the life of the compressor is extended.

  In addition, since the refrigerant containing the liquid that has reached the bypass chamber is discharged to the discharge chamber through the communication hole instead of the low-pressure side path, it can also be used as a fixed displacement compressor by closing the bypass outlet hole. Can do. That is, the compression unit can be used for both variable capacity type and fixed capacity type compressors, and contributes to a reduction in the manufacturing cost of the compressor by sharing parts.

According to the second aspect of the present invention, since the communication hole for communicating the bypass chamber and the discharge chamber is provided in the fixed scroll, the liquid compression can be prevented without being restricted by the arrangement of the bypass chamber or the like. Figured.
Furthermore, according to the invention described in claim 3, the flow of the refrigerant to the bypass path is ensured, and the efficiency of the compressor is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a scroll compressor according to this embodiment. The compressor 2 is incorporated in a refrigeration circuit of a gas engine driven heat pump (GHP) system. This refrigeration circuit is provided with a circulation path through which refrigerant, which is a working gas, circulates, and the compressor 2 sucks refrigerant from the return path (low-pressure side path 4) of the circulation path and compresses this refrigerant, and in principle the circulation path To the forward path (high-pressure side path 6).

  The compressor 2 is formed of a front housing 14 and a casing 16, and the front housing 14 has a stepped cylindrical shape having a large diameter toward the casing 16, and has both open ends. On the other hand, the casing 16 has a cup shape that opens toward the large-diameter end of the front housing 14, and the open end is airtightly fitted to the large-diameter end of the front housing 14 via an O-ring 18. The housings 14 and 16 are connected to each other via a plurality of connecting bolts 20.

  A crankshaft 22 is disposed in the front housing 14, and the crankshaft 22 has a small-diameter shaft portion 24 located on the small-diameter end side of the front housing 14 and a large-diameter shaft portion 26 located on the casing 16 side. The small-diameter shaft portion 24 is rotatably supported by the front housing 14 via a front bearing 28 and the large-diameter shaft portion 26 via a rear bearing 30. Further, a shaft seal unit 32 is disposed between the front bearing 28 and the rear bearing 30 to partition the front housing 14 in an airtight manner.

  The small diameter shaft portion 24 protrudes from the front housing 14, and a driving pulley 36 incorporating an electromagnetic clutch 34 is attached to the protruding end. The driving pulley 36 is rotatably supported by the front housing 14 via a bearing 37. Yes. The power of the gas engine is transmitted to the drive pulley 36 via a drive belt (not shown), and the rotation of the drive pulley 36 can be transmitted to the crankshaft 22 via the electromagnetic clutch 34. Therefore, when the electromagnetic clutch 34 is turned on during driving of the gas engine, the crankshaft 22 rotates integrally with the drive pulley 36.

On the other hand, a scroll unit (compression unit) 38 is accommodated in the casing 16.
Specifically, the scroll unit 38 includes a movable scroll 40 and a fixed scroll 46, and the movable scroll 40 includes a bottom plate 42, and a spiral extending toward the bottom plate 48 of the fixed scroll 46 at one end side of the bottom plate 42. A wrap 44 is integrally formed. On the other hand, a spiral wrap 50 extending toward the bottom plate 42 of the movable scroll 40 is also integrally formed on the bottom plate 48 of the fixed scroll 46. The spiral wraps 44 and 50 cooperate with each other to form a compression chamber 68, and the compression chamber 68 is centered from the outer peripheral side in the radial direction of the spiral wraps 44 and 50 by the revolving motion of the movable scroll 40 with respect to the fixed scroll 46. The volume is reduced at this time. As a result, the refrigerant in the suction chamber 72 is compressed in the compression chamber 68 and discharged toward the high-pressure side path 6.

  In order to impart a turning motion to the movable scroll 40 described above, the other end side of the bottom plate 42 of the movable scroll 40 is rotatably supported by an eccentric bush 54 via a drive bearing 52. The eccentric bush 54 is connected to a crank pin 56 that protrudes eccentrically from the large-diameter shaft portion 26. Note that reference numeral 58 in FIG. 1 indicates a counterweight, and this counterweight 58 is attached to the eccentric bush 54.

  Further, the rotation of the movable scroll 40 is prevented by the ball coupling 60. That is, the ball coupling 60 is supported by the other end of the bottom plate 42 and the large-diameter end of the front housing 14, respectively, and a pair of ring plates 62 each having an annular race with spaced pockets in the circumferential direction. And a ball 64 sandwiched between the annular races of the ring plate 62.

  On the other hand, the fixed scroll 46 is bolted to the casing 16, and the bottom plate 48 cooperates with the O-ring 66 to partition the inside of the casing 16 from the compression chamber 68 side to the discharge chamber 70 side. Further, a discharge hole 74 communicating with the compression chamber 68 is formed in a substantially central portion of the bottom plate 48 so as to penetrate the bottom plate 48, and the discharge hole 74 is opened and closed by a reed valve 76 serving as a discharge valve. . The reed valve 76 is bolted together with the valve retainer 78 on one end surface side of the bottom plate 48, that is, on the back surface side of the bottom plate 48. Further, a suction port communicating with the suction chamber 72 and a discharge port communicating with the discharge chamber 70 are formed on the peripheral wall of the casing 16, respectively. The suction port is connected to the low-pressure side path 4 described above, and the discharge port is It is connected to the high voltage side path 6.

By the way, the scroll unit 38 of this embodiment includes a bypass chamber 80 on the discharge chamber 70 side, in other words, on the back side of the bottom plate 48 of the fixed scroll 46.
Specifically, as shown in the figure, the fixed scroll 46 is provided with a partition wall 81 extending from the back surface of the bottom plate 48 until it comes into contact with the bottomed portion of the casing 16. The discharge chamber 70 located outside thereof is partitioned from the bypass chamber 80 located inside thereof. The partition wall 81 is formed so as to provide a reverse U-shaped bypass chamber 80 that covers the periphery of the discharge hole 74 and has a bottomed portion at an appropriate position in the longitudinal direction of the reed valve 76. (Figure 3).

  Further, as shown in FIG. 2 (only the fixed scroll is shown for the sake of explanation), the bottom plate 48 of the fixed scroll 46 is provided with bypass holes 82 and 82 communicating with the compression chamber 68 side through the bottom plate 48. It has been. The bypass holes 82 and 82 are formed at positions where the discharge hole 74 is sandwiched in a front view of the bottom plate 48 and communicate with the bypass chamber 80. That is, the bypass holes 82 and 82 of the present embodiment direct not the compressed refrigerant but the refrigerant in the middle of compression (intermediate pressure stage) to the bypass chamber 80, and are centered from the radially outer peripheral side of the spiral wraps 44 and 50. A compression chamber 68 that moves toward the outlet plate 74 is formed in the bottom plate 48 at an appropriate position before reaching the discharge hole 74. Thereby, when the refrigerant from the suction chamber 72 contains liquid, the refrigerant can be introduced into the bypass hole 82 instead of the discharge hole 74. The bypass holes 82, 82 are opened and closed by an inverted U-shaped reed valve 84 that follows the shape of the bypass chamber 80, and are bolted at the bottomed portion (FIG. 3).

The bypass chamber 80 is connected to the path 10 via a lead-out hole 86 drilled toward the outer peripheral wall of the casing 16 (FIG. 1). This path 10 is connected to the low-pressure side path 4 via the variable throttle mechanism 8, and the refrigerant that reaches the outlet hole 86 via the compression chamber 68 and the bypass chamber 80 bypasses the high-pressure side path 6 and bypasses the low-pressure side path. 4 is supplied.
On the other hand, the bypass chamber 80 of the present embodiment is also connected to the discharge chamber 70. Specifically, as shown in FIG. 3, a communication hole 88 is formed in the partition wall 81 along the axial direction of a lead-out hole 86 formed in the casing 16, and the communication hole 88 is formed in the bypass chamber. 80 and the discharge chamber 70 are communicated with each other. Therefore, when the refrigerant introduced into the bypass chamber 80 from the bypass hole 82 contains liquid as indicated by the alternate long and short dash line in the drawing, the refrigerant passes through the outlet hole 86 before reaching the outlet hole 86. It is arranged closer to the fixed scroll 46 and can be introduced into the communication hole 88 formed in the partition wall 81 of the fixed scroll 46 and discharged into the discharge chamber 70.

Further, the communication hole 88 is opened and closed by a check valve (valve device) 90. As shown in the figure, the check valve 90 is provided with a reed valve bolted to the outer peripheral side surface of the partition wall 81 extending from the back surface of the bottom plate 48 toward the bottomed portion of the casing 16. The valve is opened when the pressure in the bypass chamber 80 is higher than the pressure in the discharge chamber 70.
According to the compressor 2 described above, the movable scroll 40 performs a turning motion without rotating as the crankshaft 22 rotates. Such swiveling motion of the movable scroll 40 leads to the suction, compression and discharge processes of the refrigerant from the suction chamber 72 into the compression chamber 68, and the high-pressure compressed refrigerant is discharged from the compression chamber 68 through the discharge hole 74. It is discharged inside. The compressed refrigerant in the discharge chamber 70 is supplied to the high-pressure side path 6 (main path).

  The refrigerant being compressed in the compression chamber 68 is introduced into the bypass chamber 80 via the bypass hole 82 in accordance with the throttle adjustment of the variable throttle mechanism 8. Since the pressure in the bypass chamber 80 is generally lower than the pressure in the discharge chamber 70, the check valve 90 is not opened. Therefore, the intermediate pressure stage refrigerant in the bypass chamber 80 is supplied to the low-pressure side path 4 through the outlet hole 86 and the path 10 (bypass path). By adjusting the variable throttle mechanism 8, the discharge capacity is increased when the load on the refrigeration circuit is large, and the discharge capacity is decreased when the load is small.

Here, the refrigerant containing the liquid in the compression chamber 68 is also introduced into the bypass chamber 80 via the bypass hole 82. However, since the pressure in the bypass chamber 80 in this case exceeds the pressure in the discharge chamber 70, the check valve 90 is opened. Therefore, the refrigerant containing the liquid in the bypass chamber 80 is discharged to the discharge chamber 70 through the communication hole 88.
As described above, in the compressor 2 of the present embodiment, even if a refrigerant containing a liquid exists in the compression chamber 68, the refrigerant is directly compressed into the discharge chamber 70 through the discharge hole 74 after being liquid compressed. Instead of reaching the liquid chamber, it is introduced into the bypass chamber 80 before being compressed, and indirectly reaches the discharge chamber 70 via the communication hole 88 from the bypass chamber 80. Damage is prevented. Accordingly, no impact pressure is applied to the discharge chamber 70, and damage to the reed valve 76 as a discharge valve is avoided, thereby extending the life of the compressor 2.

The communication hole 88 is provided in the partition wall 81 extending from the back surface of the fixed scroll 46 toward the bottomed portion of the casing 16, and the check valve 90 is also provided on the outer peripheral side surface of the partition wall 81. Therefore, the liquid compression can be prevented without being restricted by the arrangement of the bypass chamber 80 and the outlet hole 86.
Furthermore, the communication hole 88 is opened and closed by the check valve 90, whereby the flow of the refrigerant from the path 10 to the low pressure side path 4 is ensured. That is, the function as a variable capacity compressor is maintained, contributing to the improvement of the efficiency of the compressor, and the passage 10 is not opened by the variable throttle mechanism 8 by the configuration of the communication hole 88 and the check valve 90. However, the liquid compression can be prevented.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the check valve 90 described above may be constituted by a ball valve or the like in addition to the reed valve.
Moreover, in the said embodiment, although the communicating hole 88 is opened and closed by the non-return valve 90, it is not necessarily limited to this form. Specifically, as long as the communication hole 88 is formed in the fixed scroll 46, the check valve 90 may not be provided, and in this case, it functions as a fixed capacity compressor. That is, the refrigerant that has reached the bypass chamber 80 is always discharged to the discharge chamber 70 through the communication hole 88 without being affected by the shutoff pressure of the check valve 90, so that the discharge capacity of the compressor does not change. . As a result, liquid compression can be prevented in the same manner as described above. Furthermore, the scroll unit, in particular, this fixed scroll can be applied to both variable capacity type and fixed capacity type compressors, and compression by common parts is used. There is an effect that it contributes to the reduction of the manufacturing cost of the machine.

It is a longitudinal section of a scroll compressor concerning one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1.

Explanation of symbols

2 Scroll compressor 4 Low pressure side path 6 High pressure side path 14 Front housing 16 Casing 22 Crankshaft 38 Scroll unit (compression unit)
40 movable scroll 46 fixed scroll 68 compression chamber 70 discharge chamber 80 bypass chamber 88 communication hole 90 check valve (valve device)

Claims (3)

A front housing and a casing airtightly fitted to the front housing;
A crankshaft rotatably supported in the front housing;
A compression unit having a movable scroll housed in the casing and driven by the crankshaft to perform a swiveling motion to perform a series of refrigerant suction, compression and discharge processes in cooperation with the fixed scroll;
The compression unit is
A compression chamber that is formed by the fixed scroll and the movable scroll and compresses the refrigerant sucked from the low-pressure side path of the refrigeration circuit;
A discharge chamber for supplying high-pressure compressed refrigerant from the compression chamber to the high-pressure side path of the refrigeration circuit;
A bypass chamber that bypasses the high-pressure side path and connects the compression chamber and the low-pressure side path by an outlet hole ;
The bypass chamber and the discharge chamber communicate with each other closer to the compression chamber than the outlet hole , and a communication hole for discharging the refrigerant containing the liquid in the compression chamber to the discharge chamber through the bypass chamber. Scroll compressor characterized by.   The scroll compressor according to claim 1, wherein the communication hole is formed in the fixed scroll. The compression unit further includes a valve device that opens and closes the communication hole,
The scroll compressor according to claim 1 or 2, wherein the valve device is opened when a pressure in the bypass chamber is higher than a pressure in the discharge chamber.

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