Scroll Compressor
The scroll compressor addresses orbiting scroll instability and power loss by using a back pressure chamber with communication holes to stabilize pressure, thereby reducing swinging and friction.
Patent Information
- Application Number
- JP2022015340
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-02-03
- Publication Date
- 2025-12-24
- Estimated Expiration
- 2042-02-03
Smart Images
Figure 0007791730000001 
Figure 0007791730000002 
Figure 0007791730000003
Abstract
Description
[Technical Field]
[0001] The present invention relates to a scroll compressor for compressing a gas. [Background technology]
[0002] 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 relative to the fixed scroll, and a plurality of compression chambers formed between the orbiting scroll wrap and the fixed scroll wrap. Each compression chamber moves along the orbiting scroll wrap as the orbiting scroll orbits, compressing gas and finally discharging the compressed gas.
[0003] The pressures in the multiple compression chambers become thrust forces that act in a direction that moves the orbiting scroll away 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 the wrap of the orbiting scroll, in a recess in the fixed case), and gas being compressed or discharged gas is introduced into this back pressure chamber. The pressure in the back pressure chamber supports the thrust force of the orbiting scroll. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Patent No. 2824338 Summary of the Invention [Problem to be solved by the invention]
[0005] As the orbiting scroll orbits, the thrust force of the orbiting scroll changes. More specifically, as the orbiting scroll orbits, the multiple compression chambers move and their cross-sectional areas change, causing the center of gravity of the thrust force to shift. In particular, when one of the multiple compression chambers starts discharging compressed gas, the cross-sectional areas of the multiple compression chambers change significantly, causing a significant change in the position of the center of gravity of the thrust force. At this time, the change in the moment tending to tilt the orbiting scroll also becomes significant, increasing the likelihood of the orbiting scroll swinging.
[0006] If gas being compressed is constantly introduced into the back pressure chamber, the pressure in the back pressure chamber may become insufficient at the timings described above, which may cause the orbiting scroll to oscillate.On the other hand, if discharge gas is constantly introduced into the back pressure chamber, the pressure in the back pressure chamber may become excessive at times other than the timings described above, which may increase power loss, which is the friction loss between the orbiting scroll and the fixed scroll.
[0007] The present invention has been made in view of the above circumstances, and one of its objects is to suppress the swinging of the orbiting scroll and to suppress power loss. [Means for solving the problem]
[0008] The present invention includes a plurality of means for solving the above-mentioned problems, and one example thereof is a scroll compressor including a fixed scroll having a spiral wrap, an orbiting scroll having a spiral wrap, a drive shaft for orbiting the orbiting scroll relative to the fixed scroll, a plurality of compression chambers formed between the wrap of the orbiting scroll and the wrap of the fixed scroll, a back pressure chamber formed on the back side of the orbiting scroll, and a communication hole formed in the orbiting scroll for communicating the back pressure chamber with the compression chamber, the plurality of compression chambers are composed of an outer circumferential compression chamber formed between an outer circumferential side of the wrap of the orbiting scroll and an inner circumferential side of the wrap of the fixed scroll, and an inner circumferential compression chamber formed between an inner circumferential side of the wrap of the orbiting scroll and an outer circumferential side of the wrap of the fixed scroll, When the crank angle of the drive shaft is in a first range, the back pressure chamber is Outer peripherythe compression chamber communicates with the compression chamber, and when the crank angle of the drive shaft is in a second range, the compression chamber communicates with the compression chamber through the communication hole. Outer periphery Connected to the compression chamber The first range of crank angles of the drive shaft includes a first crank angle at which the outer circumferential compression chamber starts discharging compressed gas and a second crank angle at which the inner circumferential compression chamber starts discharging compressed gas, and the second range of crank angles of the drive shaft does not include the first crank angle or the second crank angle. . [Effects of the Invention]
[0009] According to the present invention, it is possible to suppress the swinging of the orbiting scroll and also suppress power loss.
[0010] Problems, configurations, and effects other than those described above will become clear from the following description. [Brief explanation of the drawings]
[0011] [Figure 1] 1 is an axial cross-sectional view showing the structure of a scroll compressor according to a first embodiment of the present invention. [Figure 2] 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. [Figure 3] FIG. 3 is a plan view taken along an arrow III in FIG. 2. [Figure 4] FIG. 4 is a radial cross-sectional view taken along arrows IV-IV in FIG. 2. [Figure 5] 1 is a diagram showing a compression chamber in a first embodiment to which the present invention is applied. [Figure 6] 3 is a diagram showing a change in pressure in a compression chamber and an open section of a communication hole in the first embodiment to which the present invention is applied. FIG. [Figure 7] 7 is a radial cross-sectional view taken along arrows VII-VII in FIG. 1, illustrating the structure of a back pressure chamber in the first embodiment to which the present invention is applied. [Figure 8] 3A to 3C are diagrams showing the movement of the center of the orbiting scroll and the movement of the center of gravity of the thrust force in the first embodiment to which the present invention is applied. [Figure 9] FIG. 6 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. [Figure 10]FIG. 4 is a plan view showing the structure of an orbiting scroll in a second embodiment to which the present invention is applied. [Figure 11] FIG. 4 is a radial cross-sectional view showing the structure of an orbiting scroll in a second embodiment to which the present invention is applied. [Figure 12] 10 is a diagram showing a change in pressure in a compression chamber and an open section of a communication hole in a second embodiment to which the present invention is applied. FIG. [Figure 13] FIG. 10 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. DETAILED DESCRIPTION OF THE INVENTION
[0012] A first embodiment to which the present invention is applied will be described with reference to the drawings.
[0013] FIG. 1 is an axial cross-sectional view showing the structure of a scroll compressor according to this embodiment. FIG. 2 is an axial cross-sectional view showing the structure of an orbiting scroll according to this embodiment. FIG. 3 is a plan view taken along arrow III in FIG. 2, and FIG. 4 is a radial cross-sectional view taken along arrows IV-IV in FIG. 2. FIGS. 5(a) and 5(b) are diagrams showing compression chambers according to this embodiment. FIG. 6 is a diagram showing pressure changes in the compression chambers according to this embodiment and the opening sections of the communication holes. FIG. 7 is a radial cross-sectional view taken along arrows VII-VII in FIG. 1, showing the structure of a backpressure chamber according to 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. Also, FIGS. 5(a), 5(b), and 7 show an XY coordinate system with the center O1 of the drive shaft as the origin.
[0014] 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 open side of the casing 10 (the left side in FIG. 1 ). The orbiting scroll 12 is housed within the casing 10 and faces the fixed scroll 11. The drive shaft 13 is rotatably supported by a bearing 14 within the casing 10.
[0015] The fixed scroll 11 has a substantially circular end plate 15, a spiral wrap 16 standing on one side of the end plate 15 (the right side in FIG. 1), and a plurality of heat dissipation fins 17 standing on the opposite side of the end plate 15 (the left side in FIG. 1). An intake passage for drawing in gas such as air is formed in the radial outer portion of the end plate 15. A discharge passage for discharging compressed gas is formed in the radial center of the end plate 15, and a discharge pipe 18 is connected to this discharge passage.
[0016] The orbiting scroll 12 has a substantially circular end plate 19, a spiral wrap 20 erected on one side of the end plate 19 (left side of Figure 1), a plurality of heat dissipation fins 21 erected on the opposite side of the end plate 19 (right side of Figure 1), and a plate 22 provided on the tip side of the plurality of heat dissipation fins 21 (right side of Figure 1).
[0017] In this embodiment, the wrap angle of the wrap 20 of the orbiting scroll 12 is different from the wrap 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 when the wrap angle of the wrap 20 of the orbiting scroll 12 is the same as the wrap angle of the wrap 16 of the fixed scroll 11 (symmetric wrap structure).
[0018] 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 an orbiting bearing 24. The crank angle of the drive shaft 13 is the rotation angle of the line connecting the above-mentioned centers O1 and O2, and the angle at which the outer peripheral compression chamber, described below, starts compressing gas is taken as the reference angle (0°). The center O2 of the crank portion 23 of the drive shaft 13 corresponds to the center of the orbiting scroll 12.
[0019] The other end of drive shaft 13 (the right side in FIG. 1 ) protrudes outside casing 10 and is provided with pulley 25. A belt (not shown) is stretched between pulley 25 and a pulley (not shown) provided on a rotating shaft (not shown) of the electric motor. As a result, the rotational force of the electric motor is transmitted to rotate drive shaft 13, and orbiting scroll 12 orbits relative to fixed scroll 11.
[0020] A rotation prevention mechanism 26 for preventing rotation of the orbiting scroll 12 is provided within the casing 10. The rotation prevention mechanism 26 is composed of three auxiliary crankshafts spaced apart from one another in the circumferential direction of the drive shaft 13, three bearings provided on the plate 22 of the orbiting scroll 12 to support one end of each of the three auxiliary crankshafts, and three bearings provided in the casing 10 to support the other end of each of the three auxiliary crankshafts.
[0021] The multiple compression chambers are formed between the wrap 20 of the orbiting scroll 12 and the wrap 16 of the fixed scroll 11. The multiple compression chambers are composed of multiple outer peripheral 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 multiple inner peripheral compression chambers 27B formed between the inner peripheral side of the wrap 20 of the orbiting scroll 12 and the outer peripheral side of the wrap 16 of the fixed scroll 11 (see FIGS. 5(a) and 5(b)).
[0022] As the orbiting scroll 12 orbits, the outer circumferential compression chamber 27A moves along the wrap 20 of the orbiting scroll 12, compressing the gas (compression process), and finally discharges the compressed gas through the discharge pipe 18 (discharge process). Specifically, as shown in FIG. 5(a), the compression of the gas begins 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, resulting in an increase in pressure (see FIG. 6). Then, when the crank angle of the drive shaft 13 reaches 1310° (in other words, when the drive shaft 13 has rotated three times and the crank angle of the drive shaft 13 reaches 230°), the discharge of the compressed gas begins. During the discharge of the compressed gas, the discharge pressure (maximum pressure) is reached.
[0023] As the orbiting scroll 12 orbits, the inner compression chamber 27B moves along the wrap 20 of the orbiting scroll 12, compressing the gas (compression process), and finally discharges the compressed gas through the discharge pipe 18 (discharge process). Specifically, as shown in FIG. 5(b), compression of the gas begins 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, and 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 has rotated three times and the crank angle of the drive shaft 13 reaches 290°), discharge of the compressed gas begins. During the discharge of the compressed gas, the discharge pressure (maximum pressure) is reached.
[0024] The pressures in the multiple compression chambers become thrust forces that act in a direction (to the right in FIG. 1 ) that moves the orbiting scroll 12 away from the fixed scroll 11. In the scroll compressor of this embodiment, a back pressure chamber 28 is formed on the back side of the orbiting scroll 12 (in other words, the side opposite the wrap 20 of the orbiting scroll 12), and a communication hole 29 that communicates the back pressure chamber 28 with the outer peripheral compression chamber 27A is formed in the orbiting scroll 12 (more specifically, in the end plate 19, the heat dissipation fins 21, and the plate 22). Compressed gas is introduced from the outer peripheral compression chamber 27A to the back pressure chamber 28 through the communication hole 29. The thrust force of the orbiting scroll 12 is supported by the pressure in the back pressure chamber 28 and the bearing of the rotation prevention mechanism 26.
[0025] The back pressure chamber 28 in this embodiment is formed by a recess in a support plate 30 fixed inside the casing 10, and is formed in an annular shape so as to extend entirely around the circumference of the drive shaft 13. Seal rings 31 are attached to the inner and outer circumferential sides of the back pressure chamber 28 to prevent leakage of compressed gas from the back pressure chamber 28.
[0026] The thrust force of the orbiting scroll 12 will be described with reference to Fig. 8. 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.
[0027] 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 multiple compression chambers move and their cross-sectional areas change, causing the center of gravity of the thrust force to move. In particular, when the crank angle of the drive shaft 13 reaches a first crank angle (230° in this embodiment) at which the outer circumferential compression chamber 27A starts discharging compressed gas, the cross-sectional areas of the multiple compression chambers change significantly, causing the position of the center of gravity of the thrust force to change significantly. Furthermore, when the crank angle of the drive shaft 13 reaches a second crank angle (290° in this embodiment) at which the inner circumferential compression chamber 27B starts discharging compressed gas, the cross-sectional areas of the multiple compression chambers change significantly, causing the position of the center of gravity of the thrust force to change significantly. This increases the change in the moment that tilts the orbiting scroll 12, increasing the likelihood that the orbiting scroll 12 will swing.
[0028] Therefore, in this embodiment, when the crank angle of the drive shaft 13 is in a first range (a range of 230° to 300° in this embodiment) including the first and second crank angles described above, the back pressure chamber 28 communicates with the outer circumferential compression chamber 27A in the discharge process (the corresponding range of 1310° to 1380° as shown in FIG. 6 above) via the communication hole 29. At this time, the pressure in the back pressure chamber 28 becomes the discharge pressure (maximum pressure). This makes it possible to suppress oscillation of the orbiting scroll 12. As a result, it is possible to suppress leakage of compressed gas from the compression chamber.
[0029] Furthermore, in this embodiment, when the crank angle of the drive shaft 13 is in a second range (a range of 20° or more and less than 230° in this embodiment) that does not include the first crank angle or the second crank angle, the back pressure chamber 28 communicates with the outer peripheral compression chamber 27A in the compression process (the corresponding range of 1100° or more and less than 1310° as shown in FIG. 6 above) via 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 pressing the orbiting scroll 12 against the fixed scroll 11 can be reduced, and power loss, which is friction loss between the orbiting scroll 12 and the fixed scroll 11, can be reduced.
[0030] A second embodiment to which the present invention is applied will be described with reference to Figures 9 to 12. In this embodiment, parts equivalent to those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted where appropriate.
[0031] 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 the change in pressure in the compression chamber in this embodiment and the open section of the communication hole, and corresponds to Fig. 6 described above.
[0032] The back pressure chamber 28A in this embodiment is formed in a portion of the circumferential direction of the drive shaft 13 that corresponds to a third range (a range of 230° to 350° in this embodiment) of the crank angle of the drive shaft 13, which includes the first crank angle and the second crank angle described above. A seal ring 31 is attached to the outer periphery of the back pressure chamber 28A to prevent leakage of compressed gas from the back pressure chamber 28A.
[0033] Like the back pressure chamber 28 of the above embodiment, the back pressure chamber 28A of the present embodiment is connected to the outer peripheral compression chamber 27A in the discharge process via the communication hole 29 when the crank angle of the drive shaft 13 is in a first range, and is connected to the outer peripheral compression chamber 27A in the compression process via the communication hole 29 when the crank angle of the drive shaft 13 is in a second range.
[0034] The scroll compressor of this embodiment is equipped with other back pressure chambers 32A, 32B formed on the back side of the orbiting scroll 12, another communication hole 33A formed in the orbiting scroll 12 and connecting the other back pressure chamber 32A to the inner compression chamber 27B during the compression process, and another communication hole 33B formed in the orbiting scroll 12 and connecting the other back pressure chamber 32B to the outer compression chamber 27A during the compression process.
[0035] Like back pressure chamber 28A, the other back pressure chambers 32A, 32B are formed as recesses in support plate 30. The other back pressure chambers 32A, 32B are formed in areas different from back pressure chamber 28A in the circumferential direction of drive shaft 13. Seal rings 31 are attached to the outer peripheries of the other back pressure chambers 32A, 32B to prevent leakage of compressed gas from the other back pressure chambers 32A, 32B.
[0036] The other back pressure chamber 32A communicates with the inner compression chamber 27B in the compression process (the corresponding range of 580° to 900° as shown in FIG. 12) via the other communication hole 33A when the crank angle of the drive shaft 13 is within a predetermined range (40° to 360° in this embodiment). 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.
[0037] The other back pressure chamber 32B communicates with the outer peripheral compression chamber 27A in the compression process (corresponding range of 660° to 950° as shown in FIG. 12) via the other communication hole 33B when the crank angle of the drive shaft 13 is within a predetermined range (120° to 360° and 0° to 50° in this embodiment). 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.
[0038] In the present embodiment configured as described above, as in the first embodiment, it is possible to suppress the swinging of the orbiting scroll 12 and to suppress power loss. Furthermore, the positions of the other communication holes 33A, 33B can be changed to adjust the pressures in the other back pressure chambers 32A, 32B in accordance with the thrust force of the orbiting scroll 12 according to the specifications of the scroll compressor, which further suppresses power loss.
[0039] A third embodiment to which the present invention is applied will be described with reference to Fig. 13. In this embodiment, parts equivalent to those in the first and second embodiments are given the same reference numerals, and descriptions thereof will be omitted as appropriate.
[0040] The back pressure chamber 28B in this embodiment is formed in a portion of the circumferential direction of the drive shaft 13 that corresponds to a third range (a range of 220° to 300° in this embodiment) of the crank angle of the drive shaft 13, which includes the first crank angle and the second crank angle described above. A seal ring 31 is attached to the outer periphery of the back pressure chamber 28B to prevent leakage of compressed gas from the back pressure chamber 28B.
[0041] Similar to the back pressure chambers 28, 28A of the above-described embodiments, the back pressure chamber 28B of the present embodiment is connected to the outer peripheral compression chamber 27A in the discharge process via the communication hole 29 when the crank angle of the drive shaft 13 is in a first range, and is connected to the outer peripheral compression chamber 27A in the compression process via the communication hole 29 when the crank angle of the drive shaft 13 is in a second range.
[0042] The scroll compressor of this embodiment is provided with another back pressure chamber 32C formed on the back side of the orbiting scroll 12, and another communication hole (for example, the above-mentioned other communication hole 33A or 33B) formed in the orbiting scroll 12 and connecting the other back pressure chamber 32C to the inner compression chamber 27B during the compression process or the outer compression chamber 27A during the compression process.
[0043] Similar to back pressure chamber 28B, other back pressure chamber 32C is formed by a recess in support plate 30. Other back pressure chamber 32C is formed to surround back pressure chamber 28B and extend over the entire circumferential direction of drive shaft 13. A seal ring 31 is attached to the outer periphery of other back pressure chamber 32C to prevent leakage of compressed gas from other back pressure chamber 32C.
[0044] 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 via 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.
[0045] In the present embodiment configured as described above, as in the first and second embodiments, it is possible to suppress the oscillation of the orbiting scroll 12 and to suppress power loss. Furthermore, as in the second embodiment, it is possible to adjust the pressure of the other back pressure chamber 32C by changing the position of the other communication holes in accordance with the thrust force of the orbiting scroll 12 according to the specifications of the scroll compressor, thereby further suppressing power loss. Furthermore, it is possible to reduce the pressure difference between the back pressure chamber 28B and its surroundings, thereby further suppressing leakage of compressed gas from the back pressure chamber 28B. [Explanation of symbols]
[0046] 11... Fixed scroll, 12... Orbiting scroll, 13... Drive shaft, 16... Wrap, 20... Wrap, 27A... Outer circumferential compression chamber, 27B... Inner circumferential compression chamber, 28, 28A, 28B... Back pressure chamber, 29... Communication hole, 32A, 32B, 32C... Other back pressure chamber, 33A, 33B... Other communication hole
Claims
1. a fixed scroll having a spiral wrap; an orbiting scroll having a spiral wrap; a drive shaft that rotates the orbiting scroll relative to the fixed scroll; a plurality of compression chambers formed between the wrap of the orbiting scroll and the wrap of the fixed scroll; a back pressure chamber formed on the back side of the orbiting scroll; a communication hole formed in the orbiting scroll, the communication hole connecting the back pressure chamber and the compression chamber, the plurality of compression chambers are composed of an outer circumferential compression chamber formed between an outer circumferential side of the wrap of the orbiting scroll and an inner circumferential side of the wrap of the fixed scroll, and an inner circumferential compression chamber formed between an inner circumferential side of the wrap of the orbiting scroll and an outer circumferential side of the wrap of the fixed scroll, the back pressure chamber communicates with the outer peripheral compression chamber during a discharge phase via the communication hole when the crank angle of the drive shaft is in a first range, and communicates with the outer peripheral compression chamber during a compression phase via the communication hole when the crank angle of the drive shaft is in a second range; the first range of crank angles of the drive shaft includes a first crank angle at which the outer-periphery-side compression chamber starts discharging compressed gas and a second crank angle at which the inner-periphery-side compression chamber starts discharging compressed gas, The 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.
2. 2. The scroll compressor according to claim 1, the back pressure chamber is formed in a portion of the circumferential direction of the drive shaft, the portion corresponding to a third range of crank angles of the drive shaft including the first crank angle and the second crank angle.
3. The scroll compressor according to claim 2, Another back pressure chamber formed on the back side of the orbiting scroll; another communication hole formed in the orbiting scroll, which communicates the other back pressure chamber with the outer circumferential compression chamber during a compression process or the inner circumferential compression chamber during a compression process, The scroll compressor is characterized in that the other back pressure chamber is configured to have a lower pressure than the back pressure chamber.
4. The scroll compressor according to claim 3, The scroll compressor is characterized in that the other back pressure chamber is formed over the entire circumferential direction of the drive shaft while surrounding the back pressure chamber.
Citation Information
Patent Citations
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