JP2023113179A - scroll compressor - Google Patents

Abstract

To provide a scroll compressor capable of suppressing fluctuation of a turning scroll and suppressing power loss.SOLUTION: A scroll compressor includes: a fixed scroll 11 having a spiral lap 16; a turning scroll 12 having a spiral lap 20; a driving shaft 13 for turning the turning scroll 12 to the fixed scroll 11; a plurality of compression chambers formed between the lap 20 of the turning scroll 12 and the lap 16 of the fixed scroll 11; a back pressure chamber 28 formed at a back face side of the turning scroll 12; and a communication hole 29 formed on the turning scroll 12 for communicating the back pressure chamber 28 with the compression chamber. The back pressure chamber 28 is in communication with the compression chamber in a discharge process via the communication hole 29 when a crank angle of the driving shaft 13 is within a first range, and in communication with the compression chamber in a compression process via the communication hole 29 when the crank angle of the driving shaft 13 is within a second range.SELECTED DRAWING: Figure 6

Description

The present invention relates to a scroll compressor for compressing gas.

The scroll compressor includes a fixed scroll having a spiral wrap, an orbiting scroll having a spiral wrap, a drive shaft for orbiting the orbiting scroll with respect to the fixed scroll, and between the wrap of the orbiting scroll and the wrap of the fixed scroll. and a plurality of compression chambers formed by As the orbiting scroll orbits, each compression chamber compresses gas while moving along the wrap of the orbiting scroll, and finally discharges the compressed gas.

The pressures in the plurality of compression chambers serve as thrust forces acting in the direction of separating the orbiting scroll from the fixed scroll. In the scroll compressor of Patent Document 1, a back pressure chamber is formed on the back side of the orbiting scroll (more specifically, on the side opposite to the wrap of the orbiting scroll and in the depression of the fixed case). Introduce the gas being compressed or the discharge gas. The pressure in the back pressure chamber supports the thrust force of the orbiting scroll.

Japanese Patent No. 2824338

The thrust force of the orbiting scroll changes as the orbiting scroll orbits. More specifically, as the orbiting scroll orbits, the plurality of compression chambers move and their cross-sectional areas change, so the center of gravity of the thrust force moves. In particular, the cross-sectional areas of the plurality of compression chambers change significantly at the timing when one of the plurality of compression chambers starts discharging the compressed gas, so the position of the center of gravity of the thrust force changes significantly. At this time, the change in the moment that tends to tilt the orbiting scroll also increases, increasing the possibility that the orbiting scroll will oscillate.

If the gas that is being compressed is always introduced into the back pressure chamber, the pressure in the back pressure chamber may become insufficient at the timing described above, causing the orbiting scroll to oscillate. On the other hand, if the discharge gas is constantly introduced into the back pressure chamber, the pressure in the back pressure chamber becomes excessive at timings other than the timing described above, and the power loss, which is the friction loss between the orbiting scroll and the fixed scroll, increases. there is a possibility.

The present invention has been made in view of the above problems, and one of the objects thereof is to suppress the oscillation of the orbiting scroll and suppress the power loss.

In order to solve the above problems, the configurations described in the claims are applied. The present invention includes a plurality of means for solving the above problems. To give an example, the fixed scroll having a spiral wrap, the orbiting scroll having a spiral wrap, and the fixed scroll a drive shaft for orbiting the orbiting scroll; a plurality of compression chambers formed between the wrap of the orbiting scroll and the wrap of the fixed scroll; and a back pressure chamber formed on the back side of the orbiting scroll. and a communication hole formed in the orbiting scroll and communicating between the back pressure chamber and the compression chamber, wherein the back pressure chamber has a crank angle of the drive shaft within a first range. Sometimes, it communicates with the compression chamber in the discharge process through the communication hole, and communicates with the compression chamber in the compression process through the communication hole when the crank angle of the drive shaft is in the second range.

ADVANTAGE OF THE INVENTION According to this invention, the oscillation of an orbiting scroll can be suppressed and power loss can be suppressed.

Problems, configurations, and effects other than those described above will be clarified by the following description.

BRIEF DESCRIPTION OF THE DRAWINGS It is an axial sectional view showing the structure of the scroll compressor in 1st Embodiment to which this invention is applied. 1 is an axial cross-sectional view showing the structure of an orbiting scroll in a first embodiment to which the present invention is applied; FIG. 3 is a plan view according to arrow III in FIG. 2; FIG. FIG. 3 is a radial cross-sectional view taken along line IV-IV of FIG. 2; It is a figure showing the compression chamber in 1st Embodiment to which this invention is applied. FIG. 4 is a diagram showing changes in pressure in compression chambers and opening sections of communication holes in the first embodiment to which the present invention is applied. FIG. 2 is a radial cross-sectional view taken along line VII-VII in FIG. 1, showing the structure of the back pressure chamber in the first embodiment to which the present invention is applied; FIG. 4 is a diagram showing movement of the center of the orbiting scroll and movement of the center of gravity of the thrust force in the first embodiment to which the present invention is applied; FIG. 5 is a radial cross-sectional view showing the structure of a back pressure chamber in a second embodiment to which the present invention is applied; FIG. 10 is a plan view showing the structure of an orbiting scroll in a second embodiment to which the present invention is applied; FIG. 6 is a radial cross-sectional view showing the structure of an orbiting scroll in a second embodiment to which the present invention is applied; It is a figure showing the opening section of a communicating hole while showing the change of the pressure of the compression chamber in 2nd Embodiment to which this invention is applied. FIG. 11 is a radial cross-sectional view showing the structure of a back pressure chamber in a third embodiment to which the present invention is applied;

A first embodiment to which the present invention is applied will be described with reference to the drawings.

FIG. 1 is an axial sectional view showing the structure of the scroll compressor in this embodiment. FIG. 2 is an axial sectional view showing the structure of the orbiting scroll in this embodiment. 3 is a plan view along arrow III in FIG. 2, and FIG. 4 is a radial sectional view along arrow IV-IV in FIG. 5(a) and 5(b) are diagrams showing the compression chamber in this embodiment. FIG. 6 is a diagram showing changes in the pressure of the compression chambers in the present embodiment, as well as opening sections of the communication holes. FIG. 7 is a radial cross-sectional view taken along line VII-VII in FIG. 1, showing the structure of the back pressure chamber in this embodiment. Note that FIG. 1 shows the center O1 of the drive shaft and the center O2 of the crank portion of the drive shaft. 5A, 5B, and 7 show an XY coordinate system with the center O1 of the drive shaft as the origin.

The scroll compressor of this embodiment includes a casing 10 , a fixed scroll 11 , an orbiting scroll 12 and a drive shaft 13 . The fixed scroll 11 is connected to the opening side of the casing 10 (left side in FIG. 1). The orbiting scroll 12 is housed inside the casing 10 and faces the fixed scroll 11 . The drive shaft 13 is rotatably supported by bearings 14 inside the casing 10 .

The fixed scroll 11 includes a substantially circular end plate 15, a spiral wrap 16 standing on one side of the end plate 15 (on the right side in FIG. 1), and a spiral wrap 16 standing on the opposite side of the end plate 15 (on the left side in FIG. 1). and a plurality of radiation fins 17 provided. A suction channel for sucking gas such as air is formed in the radially outer portion of the end plate 15 . A discharge passage for discharging the compressed gas is formed in the radial center of the end plate 15, and a discharge pipe 18 is connected to this discharge passage.

The orbiting scroll 12 includes a substantially circular end plate 19, a spiral wrap 20 erected on one surface side (left side in FIG. 1) of the end plate 19, and an opposite surface side (right side in FIG. 1) of the end plate 19. and a plate 22 provided on the tip side of the plurality of heat radiation fins 21 (on the right side in FIG. 1).

In this embodiment, the winding angle of the wrap 20 of the orbiting scroll 12 is different from the winding angle of the wrap 16 of the fixed scroll 11 (asymmetric wrap structure). This makes it possible to increase the compression volume or reduce the size of the machine compared to the case where the winding angle of the wrap 20 of the orbiting scroll 12 is the same as the winding angle of the wrap 16 of the fixed scroll 11 (symmetrical wrap structure). be.

A crank portion 23 is provided on one end side (left side in FIG. 1) of the drive shaft 13 . The center O2 of the crank portion 23 of the drive shaft 13 is eccentric from the center O1 of the drive shaft 13 and is connected to the boss portion of the plate 22 of the orbiting scroll 12 via the orbiting bearing 24 . The crank angle of the drive shaft 13 is the rotation angle of the straight line connecting the centers O1 and O2 described above, and is based on the angle (0°) at which the outer peripheral side compression chamber described later starts compressing gas. Note that the center O<b>2 of the crank portion 23 of the drive shaft 13 corresponds to the center of the orbiting scroll 12 .

The other end of the drive shaft 13 (right side in FIG. 1) protrudes outside the casing 10 and is provided with a pulley 25 . A belt (not shown) is stretched between a pulley (not shown) provided on a rotary shaft (not shown) of the electric motor and the pulley 25 . As a result, the rotational force of the electric motor is transmitted, the drive shaft 13 rotates, and the orbiting scroll 12 orbits with respect to the fixed scroll 11 .

A rotation prevention mechanism 26 for preventing rotation of the orbiting scroll 12 is provided in the casing 10 . The anti-rotation mechanism 26 includes three auxiliary crankshafts that are spaced apart from each other in the circumferential direction of the drive shaft 13, and a plate 22 of the orbiting scroll 12 that supports one end sides of the three auxiliary crankshafts. and three bearings that are provided in the casing 10 and support the other end sides of the three auxiliary crankshafts, respectively.

A plurality of compression chambers are formed between wraps 20 of orbiting scroll 12 and wraps 16 of fixed scroll 11 . The plurality of compression chambers include a plurality of outer peripheral side compression chambers 27A formed between the outer peripheral side of the wrap 20 of the orbiting scroll 12 and the inner peripheral side of the wrap 16 of the fixed scroll 11, and the inner peripheral side of the wrap 20 of the orbiting scroll 12. and a plurality of inner peripheral side compression chambers 27B formed between the outer peripheral side of the wrap 16 of the fixed scroll 11 (see FIGS. 5(a) and 5(b)).

As the orbiting scroll 12 orbits, the outer compression chamber 27A moves along the wrap 20 of the orbiting scroll 12, compresses the gas (compression process), and finally discharges the compressed gas through the discharge pipe 18. (Ejection process). Specifically, as shown in FIG. 5(a), gas compression is started when the crank angle of the drive shaft 13 is 0°. Then, as the crank angle of the drive shaft 13 increases, the gas is compressed while moving along the wrap 20 of the orbiting scroll 12, so the pressure increases (see FIG. 6). Then, when the crank angle of the drive shaft 13 reaches 1310° (in other words, when the drive shaft 13 rotates three times and the crank angle of the drive shaft 13 reaches 230°), the discharge of the compressed gas is started. . During discharge of the compressed gas, the discharge pressure (maximum pressure) is reached.

As the orbiting scroll 12 orbits, the inner peripheral compression chamber 27B compresses the gas (compression process) while moving along the wrap 20 of the orbiting scroll 12, and finally discharges the compressed gas through the discharge pipe 18. (discharge process). Specifically, as shown in FIG. 5(b), gas compression is started when the crank angle of the drive shaft 13 is 180°. Then, as the crank angle of the drive shaft 13 increases, the gas is compressed while moving along the wrap 20 of the orbiting scroll 12, so the pressure increases (see FIG. 6). Then, when the crank angle of the drive shaft 13 reaches 1370° (in other words, when the drive shaft 13 rotates three times and the crank angle of the drive shaft 13 reaches 290°), discharge of the compressed gas is started. . During discharge of the compressed gas, the discharge pressure (maximum pressure) is reached.

The pressure in the plurality of compression chambers serves as a thrust force acting in the direction (rightward direction in FIG. 1) separating the orbiting scroll 12 from the fixed scroll 11 . In the scroll compressor of this embodiment, the back pressure chamber 28 is formed on the back side of the orbiting scroll 12 (in other words, the side of the orbiting scroll 12 opposite to the wrap 20), and the back pressure chamber 28 and the outer compression chamber 27A are separated. A communicating hole 29 is formed in the orbiting scroll 12 (specifically, the end plate 19, the radiation fins 21, and the plate 22), and the compressed gas is introduced from the outer peripheral side compression chamber 27A to the back pressure chamber 28 through the communicating hole 29. . The pressure of the back pressure chamber 28 and the bearing of the anti-rotation mechanism 26 support the thrust force of the orbiting scroll 12 .

The back pressure chamber 28 of the present embodiment is formed by a depression in the support plate 30 fixed inside the casing 10 and is formed in an annular shape so as to extend along the entire circumferential direction of the drive shaft 13 . A seal ring 31 is attached to the inner peripheral side and the outer peripheral side of the back pressure chamber 28 to suppress leakage of compressed gas from the back pressure chamber 28 .

The thrust force of the orbiting scroll 12 will be explained using FIG. FIG. 8 is a diagram showing the movement (trajectory) of the center of the orbiting scroll 12 and the movement (change in position) of the center of gravity of the thrust force.

As the orbiting scroll 12 orbits (in other words, as the crank angle of the drive shaft 13 changes), the thrust force of the orbiting scroll 12 changes. More specifically, as the orbiting scroll 12 orbits, the plurality of compression chambers move and their cross-sectional areas change, so the center of gravity of the thrust force moves. In particular, when the crank angle of the drive shaft 13 reaches the first crank angle (230° in this embodiment) at which the outer compression chamber 27A starts discharging the compressed gas, the cross-sectional areas of the plurality of compression chambers change significantly. Therefore, the position of the center of gravity of the thrust force changes greatly. Further, when the crank angle of the drive shaft 13 reaches the second crank angle (290° in this embodiment) at which the inner compression chamber 27B starts discharging the compressed gas, the cross-sectional areas of the plurality of compression chambers are large. Since it changes, the position of the center of gravity of the thrust force changes greatly. Therefore, the change in the moment that tends to tilt the orbiting scroll 12 also increases, increasing the possibility that the orbiting scroll 12 swings.

Therefore, in the back pressure chamber 28 of the present embodiment, the crank angle of the drive shaft 13 is in a first range including the above-described first crank angle and second crank angle (a range of 230° or more and 300° or less in this embodiment). , it communicates with the outer peripheral side compression chamber 27A in the discharge process (corresponding range of 1310° or more and 1380° or less as shown in FIG. 6) through the communication hole 29 . At this time, the pressure in the back pressure chamber 28 becomes the discharge pressure (maximum pressure). Therefore, swinging of the orbiting scroll 12 can be suppressed. As a result, leakage of compressed gas from the compression chamber can be suppressed.

Further, the back pressure chamber 28 of the present embodiment has a crank angle of the drive shaft 13 in a second range (20° or more and less than 230° in this embodiment) that does not include the first crank angle and the second crank angle. At some point, it communicates with the outer peripheral side compression chamber 27A in the compression process (corresponding range of 1100° or more and less than 1310° as shown in FIG. 6) through the communication hole 29 . At this time, the pressure in the back pressure chamber 28 increases as the crank angle of the drive shaft 13 increases, but is lower than the discharge pressure. Therefore, the force that presses the orbiting scroll 12 against the fixed scroll 11 can be suppressed, and the power loss, which is the frictional loss between the orbiting scroll 12 and the fixed scroll 11, can be suppressed.

A second embodiment to which the present invention is applied will be described with reference to FIGS. 9 to 12. FIG. In addition, in this embodiment, the same code|symbol is attached|subjected to the part equivalent to 1st Embodiment, and description is abbreviate|omitted suitably.

FIG. 9 is a radial cross-sectional view showing the structure of the back pressure chamber in this embodiment, and corresponds to FIG. 7 described above. FIG. 10 is a plan view showing the structure of the orbiting scroll in this embodiment, and corresponds to FIG. 3 described above. FIG. 11 is a radial cross-sectional view showing the structure of the orbiting scroll in this embodiment, and corresponds to FIG. 4 described above. FIG. 12 is a diagram showing changes in the pressure of the compression chambers and opening sections of the communication holes in this embodiment, and corresponds to FIG. 6 described above.

The back pressure chamber 28A of this embodiment corresponds to the third range of the crank angle of the drive shaft 13 (in this embodiment, the range of 230° to 350°) including the above-described first crank angle and second crank angle. It is formed in a part of the drive shaft 13 in the circumferential direction. A seal ring 31 is attached to the outer peripheral side of the back pressure chamber 28A to suppress leakage of compressed gas from the back pressure chamber 28A.

As with the back pressure chamber 28 of the above-described embodiment, the back pressure chamber 28A of the present embodiment communicates with the outer compression chamber 27A in the discharge process through the communication hole 29 when the crank angle of the drive shaft 13 is in the first range. When the crank angle of the drive shaft 13 is in the second range, it communicates with the outer peripheral side compression chamber 27A in the compression process via the communication hole 29 .

The scroll compressor of this embodiment includes other back pressure chambers 32A and 32B formed on the back side of the orbiting scroll 12, and another back pressure chamber 32A formed in the orbiting scroll 12 and inner peripheral side compression in the compression process. Another communication hole 33A that communicates with the chamber 27B, and another communication hole 33B that is formed in the orbiting scroll 12 and communicates with the other back pressure chamber 32B and the outer peripheral side compression chamber 27A in the compression process.

The other back pressure chambers 32A and 32B are formed by recesses in the support plate 30, like the back pressure chamber 28A. The other back pressure chambers 32A and 32B are formed in other ranges in the circumferential direction of the drive shaft 13 different from the back pressure chamber 28A. A seal ring 31 is attached to the outer periphery of the other back pressure chambers 32A, 32B to prevent leakage of compressed gas from the other back pressure chambers 32A, 32B.

The other back pressure chamber 32A is compressed through another communication hole 33A when the crank angle of the drive shaft 13 is within a predetermined range (40° to 360° in this embodiment). , communicates with the corresponding inner peripheral side compression chamber 27B in the range of 580° to 900°. The pressure in the other back pressure chamber 32A increases as the crank angle of the drive shaft 13 increases, but is lower than the pressure in the back pressure chamber 28A.

The other back pressure chamber 32B is compressed through another communication hole 33B when the crank angle of the drive shaft 13 is within a predetermined range (ranges of 120° to 360° and 0° to 50° in this embodiment). It communicates with the outer peripheral side compression chamber 27A in the process (corresponding range of 660° to 950° as shown in FIG. 12). The pressure in the other back pressure chamber 32B increases as the crank angle of the drive shaft 13 increases, but is lower than the pressure in the back pressure chamber 28A.

Also in this embodiment configured as described above, it is possible to suppress swinging of the orbiting scroll 12 and power loss, as in the first embodiment. Further, according to the thrust force of the orbiting scroll 12 according to the specifications of the scroll compressor, it is possible to change the positions of the communication holes 33A and 33B to adjust the pressures of the other back pressure chambers 32A and 32B. Power loss can be further suppressed.

A third embodiment to which the present invention is applied will be described with reference to FIG. In addition, in this embodiment, the same code|symbol is attached|subjected to the part equivalent to 1st and 2nd embodiment, and description is abbreviate|omitted suitably.

The back pressure chamber 28B of the present embodiment corresponds to the third crank angle range (220° to 300° range in the present embodiment) of the drive shaft 13 including the first crank angle and the second crank angle described above. It is formed in a part of the drive shaft 13 in the circumferential direction. A seal ring 31 is attached to the outer peripheral side of the back pressure chamber 28B to suppress leakage of compressed gas from the back pressure chamber 28B.

Like the back pressure chambers 28 and 28A of the above-described embodiment, the back pressure chamber 28B of the present embodiment is configured such that when the crank angle of the drive shaft 13 is within the first range, the pressure of the back pressure chamber 28B is increased through the communication hole 29 during the discharge process. 27A, and when the crank angle of the drive shaft 13 is in the second range, it communicates with the outer peripheral side compression chamber 27A in the compression process via the communication hole 29.

The scroll compressor of this embodiment includes another back pressure chamber 32C formed on the back side of the orbiting scroll 12, another back pressure chamber 32C formed in the orbiting scroll 12, and an inner peripheral side compression chamber 27B in the compression process. Alternatively, another communication hole (for example, the other communication hole 33A or 33B described above) that communicates with the outer peripheral side compression chamber 27A in the compression process is provided.

32 C of other back pressure chambers are formed in the hollow of the support plate 30 like the back pressure chamber 28B. The other back pressure chamber 32C is formed so as to surround the back pressure chamber 28B and extend all around the drive shaft 13 in the circumferential direction. A seal ring 31 is attached to the outer peripheral side of the other back pressure chamber 32C to suppress leakage of compressed gas from the other back pressure chamber 32C.

The other back pressure chamber 32C communicates with the inner compression chamber 27B in the compression process or the outer compression chamber 27A in the compression process through another communication hole when the crank angle of the drive shaft 13 is within a predetermined range. . The pressure in the other back pressure chamber 32C increases as the crank angle of the drive shaft 13 increases, but is lower than the pressure in the back pressure chamber 28B.

Also in this embodiment configured as described above, it is possible to suppress swinging of the orbiting scroll 12 and power loss in the same manner as in the first and second embodiments. Further, as in the second embodiment, it is possible to adjust the pressure of the other back pressure chamber 32C by changing the positions of the other communication holes according to the thrust force of the orbiting scroll 12 according to the specifications of the scroll compressor. Therefore, power loss can be further reduced. Moreover, the differential pressure between the back pressure chamber 28B and its surroundings can be reduced, and leakage of the compressed gas from the back pressure chamber 28B can be further suppressed.

REFERENCE SIGNS LIST 11 fixed scroll 12 orbiting scroll 13 drive shaft 16 wrap 20 wrap 27A outer compression chamber 27B inner compression chamber 28, 28A, 28B back pressure chamber 29 Communicating holes, 32A, 32B, 32C... other back pressure chambers, 33A, 33B... other communicating holes

Claims (5)

a fixed scroll having a spiral wrap;
an orbiting scroll having a spiral wrap;
a drive shaft for orbiting the orbiting scroll with respect to the fixed scroll;
a plurality of compression chambers formed between the wraps of the orbiting scroll and the wraps of the fixed scroll;
a back pressure chamber formed on the back side of the orbiting scroll;
A scroll compressor comprising a communication hole formed in the orbiting scroll and communicating between the back pressure chamber and the compression chamber,
The back pressure chamber communicates with the compression chamber in the discharge process through the communication hole when the crank angle of the drive shaft is within the first range, and when the crank angle of the drive shaft is within the second range. A scroll compressor, characterized in that it communicates with said compression chamber in a compression process through said communication hole. The scroll compressor according to claim 1,
The plurality of compression chambers include an outer peripheral side compression chamber formed between an outer peripheral side of the wrap of the orbiting scroll and an inner peripheral side of the wrap of the fixed scroll, and an inner peripheral side of the wrap of the orbiting scroll. and an inner peripheral side compression chamber formed between the outer peripheral sides of the wraps of the fixed scroll,
The communication hole communicates the back pressure chamber and the outer peripheral compression chamber,
The first crank angle range of the drive shaft includes a first crank angle at which the outer compression chamber starts to discharge compressed gas and a second crank angle at which the inner compression chamber starts to discharge compressed gas. and
A scroll compressor, wherein the second range of crank angles of the drive shaft does not include the first crank angle and the second crank angle. The scroll compressor according to claim 2,
The back pressure chamber is formed in a part of the drive shaft in the circumferential direction corresponding to a third range of crank angles of the drive shaft including the first crank angle and the second crank angle. scroll compressor. In the scroll compressor according to claim 3,
another back pressure chamber formed on the back side of the orbiting scroll;
Another communication hole formed in the orbiting scroll and communicating with the other back pressure chamber and the outer peripheral side compression chamber in a compression process or the inner peripheral side compression chamber in a compression process,
A scroll compressor, wherein the other back pressure chamber is configured to have a pressure lower than that of the back pressure chamber. The scroll compressor according to claim 4,
The scroll compressor, wherein the other back pressure chamber surrounds the back pressure chamber and is formed in the entire circumferential direction of the drive shaft.

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