Scroll compressor

Abstract

A scroll compressor (1) with a compression mechanism (4) formed from a stationary screw (21) and a movable screw (22), each arranged on surfaces of mirror plates (23, 31) with mutually facing spiral turns (24, 32), and in which the movable screw (22) is rotated and turned relative to the stationary screw (21) in order to compress a working fluid in a compression chamber (34) formed between the turns (24, 32) of both screws (21, 22), comprising: a counter-pressure chamber (39) formed in a rear surface of the mirror plate (31) of the movable screw (22); and a first counter-pressure bore (51) and a second counter-pressure bore (52) which are formed in the mirror plate (31) of the movable screw (22) and connect the counter-pressure chamber (39) and the compression chamber (34), wherein the first counter-pressure bore (51) is formed in a position and / or dimension in which, through the rotation and rotary movement of the movable screw (22), after the first counter-pressure bore (51) is opened within the turn (24) of the stationary screw (21), the first counter-pressure bore (51) is closed by the turn (24) of the stationary screw (21), and is then not opened outside the turn (24) of the stationary screw (21), and wherein the second counter-pressure bore (52) is formed in a position and / or dimension in which, by the rotation and rotary movement of the movable screw (22), after the second counter-pressure bore (52) is opened within the turn (32) of the movable screw (22) in a first crank angle range, the second counter-pressure bore (52) is temporarily closed by the turn (24) of the stationary screw (21) and then opened within the turn (24) of the stationary screw (21) in a second crank angle range.

Description

[0001] The present invention relates to a scroll compressor which compresses a working fluid in a compression chamber formed between turns of a stationary screw and a movable screw by turning and rotating (orbiting) the movable screw in relation to the stationary screw.

[0002] This type of scroll compressor typically includes a compression mechanism consisting of a stationary screw with a helical winding on the surface of a mirror plate and a movable screw with a helical winding on the surface of a mirror plate, designed to form a compression chamber between the windings of the respective screws, with the windings facing each other, and wherein the movable screw is turned and rotated relative to the stationary screw by a motor to compress a working fluid (coolant) in the compression chamber.

[0003] In this case, a counter-pressure chamber is formed on the rear surface of the moving screw's mirror plate to press the moving screw against the stationary screw against a compression reaction force from the compression chamber. Conventionally, a counter-pressure channel is formed, causing the outlet side (outlet chamber) of the compression mechanism and the counter-pressure chamber to communicate. An opening is arranged in this counter-pressure channel, allowing an outlet pressure Pd, after being decompressed through the opening, to be supplied to the counter-pressure chamber to apply a counter-pressure load to the moving screw that overcomes the compression reaction force (see, for example,

[0004] JP 5 859 480 B2).

[0005] Furthermore, in the JP 5 859 480 B2, a bore (backpressure bore) for pressure regulation is formed in the mirror plate of the movable screw. With the formation of this backpressure bore, coolant and oil that have flowed from the backpressure channel into the backpressure chamber are returned to the compression chamber, and, for example, in an operating condition where the suction pressure Ps is low, the pressure (backpressure Pm) in the backpressure chamber is adjusted so that it is not too high.

[0006] Other scroll compressors are from DE 11 2014 005 641 T5, JP 2010 - 121 578 A, and JP 2012 - 188 978 A.

[0007] JP S58 - 190 591 A and JP S58 - 122 386 A are known.

[0008] Here we show Fig. 9 and Fig. 10. The relationship between the opening behavior of backpressure bores (H1 and H2) formed in a moving screw of a conventional scroll compressor and the pressure behavior of each part. Furthermore, it is assumed in this case that the two backpressure bores H1 and H2 are formed in the moving screw.

[0009] The counter-pressure bores H1 and H2 are opened and closed by a turn of a stationary screw during a rotational movement of the moving screw. However, conventionally, both counter-pressure bores H1 and H2 were designed to open, for example, within a crank angle range of 25° to 230°. Therefore, the opening time of each of the counter-pressure bores H1 and H2 becomes long during low-speed operation. Coolant and oil flow from a counter-pressure chamber into a compression chamber, and the compression chamber pressure rises, as described in... Fig. Figure 9 illustrates this. Consequently, the back pressure Pm (back pressure chamber pressure) also increases. As a result, the moving screw is pressed excessively against the stationary screw, and power consumption rises. Therefore, it is usually necessary to provide a pressure regulating valve to release the back pressure into a suction chamber, which causes a problem and increases costs.

[0010] On the other hand, a problem arises because, in the operating condition where the suction pressure Ps becomes low, the compression chamber pressure in a section connected to the backpressure bores H1 and H2 also becomes low, so that the backpressure Pm (backpressure chamber pressure) also does not increase as in Fig. 10 shown, and the force to push the moving screw against the stationary screw becomes too small, causing a compaction failure.

[0011] The present invention was created to solve the aforementioned conventional technical problems, and one objective of it is to provide a scroll compressor that is able to adapt to an appropriate back pressure in both a low-speed operating condition and a low-suction operating condition by improving the position or dimension of a back pressure bore.

[0012] A scroll compressor of the present invention is provided, comprising a compression mechanism consisting of a stationary screw and a movable screw, each arranged on surfaces of mirror plates with mutually facing spiral turns, in which the movable screw is rotated and rotated (orbited) in relation to the stationary screw in order to compress a working fluid in a compression chamber formed between the turns of both screws.The scroll compressor is characterized in that it has a back pressure chamber formed in a rear surface of the mirror plate of the movable screw, and a back pressure bore formed in the mirror plate of the movable screw, connecting the back pressure chamber and the compression chamber, and that the back pressure bore is formed in a position and / or dimension in which, through the rotational and rotary movement of the movable screw, after the back pressure bore is opened within the winding of the movable screw in a predetermined first crank angle range, the back pressure bore is temporarily closed by the winding of the stationary screw and then opened within the winding of the stationary screw in a predetermined second crank angle range.

[0013] The scroll compressor of the invention according to claim 2 is characterized in that, in the above invention, the counter-pressure bore is opened in a range of crank angles from 25° to 175° and 250° to 310°.

[0014] The scroll compressor of the invention according to claim 1 is further characterized in that, in the above respective inventions, a first counter-pressure bore and a second counter-pressure bore are formed in the mirror plate of the movable screw, the first counter-pressure bore being formed in a position and / or dimension in which, by the rotational and rotary movement of the movable screw, the first counter-pressure bore is opened within the winding of the stationary screw and then closed by the winding of the stationary screw, and the second counter-pressure bore is formed in a position and / or dimension in which, by the rotational and rotary movement of the movable screw, after the second counter-pressure bore is opened within the winding of the movable screw in the first crank angle range,The second counter-pressure bore is temporarily closed by the winding of the stationary screw and then opened within the winding of the stationary screw in the second crank angle range.

[0015] The scroll compressor of the invention according to claim 1 is further characterized in that, in the above invention, the first counter-pressure bore is formed in a position and / or dimension in which, through the rotational and rotary movement of the movable screw, after the first counter-pressure bore is opened within the winding of the stationary screw, the first counter-pressure bore is closed by the winding of the stationary screw, and is then not opened outside the winding of the stationary screw.

[0016] The scroll compressor of the invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the first counter-pressure bore is opened in a range of the crank angle from 25° to 215°.

[0017] The scroll compressor of the invention according to claim 4 is characterized in that it has, in the respective above inventions, a back pressure channel which connects the outlet side of the compression mechanism and the back pressure chamber, and a pressure reduction section provided in the back pressure channel.

[0018] According to the present invention, a scroll compressor is provided with a compression mechanism comprising a stationary screw and a movable screw, each arranged on surfaces of mirror plates with mutually facing helical turns. The movable screw is rotated and orbited relative to the stationary screw to compress a working fluid in a compression chamber formed between the turns of the two screws. The scroll compressor includes a back pressure chamber formed in a rear surface of the mirror plate of the movable screw and a back pressure bore formed in the mirror plate of the movable screw, connecting the back pressure chamber and the compression chamber.The backpressure bore is designed in a position and / or dimension such that, due to the rotational movement of the moving screw, after the backpressure bore opens within the turn of the moving screw in a predetermined first crank angle range, the backpressure bore is temporarily closed by the turn of the stationary screw and then opened within the turn of the stationary screw in a predetermined second crank angle range. It is therefore possible to make the first crank angle range in which the backpressure bore opens more limited than conventional designs, to shorten the time in which the backpressure bore opens during low-speed operation, and to restrict the amount of coolant and oil flowing from the backpressure chamber into the compression chamber. Consequently, it is possible to prevent an increase in backpressure due to an increase in the compression chamber.

[0019] On the other hand, since the backpressure bore is reopened in the second crank angle range, the backpressure chamber and the compression chamber are connected once the compression chamber pressure has risen sufficiently. Consequently, a higher compression chamber pressure can be supplied to the backpressure chamber, and a reduction in backpressure during an operating condition where the suction pressure becomes low can also be prevented.

[0020] According to the present invention and from the foregoing, it follows that when adjusting the back pressure to an appropriate back pressure under both the low-speed operating condition and the low-suction-pressure operating condition, and when eliminating the inconvenience of excessive pressure of the moving screw against the stationary screw under the low-suction-pressure operating condition, which increases power consumption and leads to an increase in costs, it is also possible to eliminate the inconvenience of the back pressure being reduced under the low-suction-pressure operating condition, and the force with which the moving screw is pressed against the stationary screw becoming too low, thereby causing compaction failure.

[0021] In this case, it is effective to open the counter-pressure bore in a range of crank angles from 25° to 175° and 250° to 310°, as for example in the invention according to claim 2.

[0022] Furthermore, as in the invention according to claim 1, in the scroll compressor, which is provided with a first counter-pressure bore and a second counter-pressure bore, the first counter-pressure bore is configured in a position and / or dimension in which the first counter-pressure bore is opened within the turn of the stationary screw and then closed by the turn of the stationary screw. The second counter-pressure bore is configured in a position and / or dimension in which, after the second counter-pressure bore is opened within the turn of the movable screw in the first crank angle range, the second counter-pressure bore is temporarily closed by the turn of the stationary screw and then opened within the turn of the stationary screw in the second crank angle range.

[0023] Furthermore, as in the invention according to claim 1, the first counter-pressure bore is configured in a position and / or dimension such that, due to the rotational and rotary movement of the movable screw, after the first counter-pressure bore is opened within the turn of the stationary screw, the first counter-pressure bore is closed by the turn of the stationary screw and is then not opened outside the turn of the stationary screw. This therefore also avoids any inconvenience caused by the first counter-pressure bore being in contact with the compression chamber, which is at low pressure.

[0024] In this case, as in the invention according to claim 3, it is also effective to open the first counter-pressure bore in a range of the crank angle from 25° to 215°, and to open the second counter-pressure bore in a range of the crank angle from 25° to 175° and from 250° to 310°.

[0025] The above invention is therefore particularly suitable for the scroll compressor which has a back pressure channel connecting the outlet side of the compression mechanism and the back pressure chamber, and a pressure reducing section provided in the back pressure channel, as in the invention according to claim 4. Fig. Figure 1 is a sectional view of a scroll compressor according to an embodiment to which the present invention is applied; Fig. Figure 2 is a view showing a rotational and rotary motion of a movable screw of the scroll compressor according to Fig. 1 and represents the opening and closing of a counter-pressure bore (crank angle 0°); Fig. Figure 3 is a view that similarly depicts a rotational and rotary movement of the movable screw of the scroll compressor and the opening and closing of the counter-pressure bore (crank angle 90°); Fig. Figure 4 is a view that similarly shows a rotational and rotary motion of the movable screw of the scroll compressor and the opening and closing of the counter-pressure bore (crank angle 180°); Fig. Figure 5 is a view that similarly shows a rotational and rotary motion of the movable screw of the scroll compressor and the opening and closing of the counter-pressure bore (crank angle 270°); Fig. Figure 6 is a view showing a crank angle of a rotating shaft of the scroll compressor according to Fig. 1 and represents a degree of opening of the counter-pressure opening; Fig. 7 is a view that describes the pressure behavior of a compression chamber of the scroll compressor according to Fig. 1 and represents the opening behavior of the back pressure bores (operating state at low speed); Fig. Figure 8 is a view that similarly depicts the pressure behavior of the compression chamber and the opening behavior of the back pressure bores (operating condition with low suction pressure); Fig. Figure 9 is a view that illustrates the pressure behavior of a compression chamber of a conventional scroll compressor and the opening behavior of backpressure bores (low-speed operating condition); and Fig. Figure 10 is a view that similarly represents the pressure behavior of a conventional compression chamber and the opening behavior of the back pressure bores (operating condition with low suction pressure).

[0026] The embodiments of the present invention are described in detail below with reference to the drawings. Fig. Figure 1 is a sectional view of a scroll compressor according to an embodiment to which the present invention is applied. The scroll compressor 1 of the embodiment is, for example, a so-called inverter-integrated scroll compressor, which is used in a coolant circuit of a vehicle air conditioning system, draws in a coolant as the working fluid of the vehicle air conditioning system, compresses it and discharges it, and comprises an electric motor 2, an inverter 3 for operating the electric motor 2 and a compression mechanism 4 driven by the electric motor 2.

[0027] The scroll compressor 1 of this embodiment comprises a main housing 6, which accommodates the electric motor 2 and the inverter 3, a compression mechanism housing 7, which accommodates the compression mechanism 4, an inverter cover 8, and a compression mechanism cover 9. Furthermore, the main housing 6, the compression mechanism housing 7, the inverter cover 8, and the compression mechanism cover 9 are all made of metal (aluminum in this embodiment). They are integrally connected to form a housing 11 of the scroll compressor 1. That is, the compression mechanism cover 9 forms part of the housing 11.

[0028] The main housing 6 is formed by a tubular circumferential wall section 6A and a partition section 6B. The partition section 6B divides the interior of the main housing 6 into a motor mounting section 12, which houses the electric motor 2, and an inverter mounting section 13, which houses the inverter 3. The inverter mounting section 13 has an open end face, and this opening is closed by the inverter cover 8 after the inverter 3 has been installed.

[0029] The motor mounting section 12 also has the other end face, which is open, and this opening is closed by the compression mechanism housing 7 after the electric motor 2 is housed therein. A support section 16 for bearing an end section (end section on the side opposite the compression mechanism 4) of a rotating shaft 14 of the electric motor 2 is provided protruding on the partition wall part 6B.

[0030] The compression mechanism housing 7 has an opening on the side opposite the main housing 6, and this opening is closed by the compression mechanism cover 9 after the compression mechanism 4 is installed therein. The compression mechanism housing 7 is formed by a tubular circumferential wall section 7A and a frame section 7B at one end (main housing side 6) thereof. The compression mechanism 4 is housed in a space divided by this circumferential wall section 7A and the frame section 7B. The frame section 7B forms a partition that separates the interior of the main housing 6 from the interior of the compression mechanism housing 7.

[0031] Furthermore, the frame part 7B is provided with a through-hole 17 for inserting the other end of the rotating shaft 14 of the electric motor 2 (the end on the side of the compression mechanism 4). A front bearing 18, as a bearing element that supports the other end of the rotating shaft 14, is mounted on the side of the compression mechanism 4 of the through-hole 17. In addition, reference numeral 19 designates a sealing material that seals the outer circumferential surface of the rotating shaft 14 and the inside of the compression mechanism housing 7 in the area of ​​the through-hole 17.

[0032] The electric motor 2 consists of a stator 25, around which a coil 35 is wound, and a rotor 30. Then, for example, a direct current from a battery (not shown) of a vehicle is converted by the inverter into a three-phase alternating current, which is supplied to the coil 35 of the electric motor 2, so that the rotor 30 is set into rotation.

[0033] Furthermore, an intake port (not shown) is formed in the main housing 6. After the coolant drawn in through the intake port passes through the interior of the main housing 6, it is drawn into an intake area 37, which will be described later, outside the compression mechanism 4 in the compression mechanism housing 7. Consequently, the electric motor 2 is cooled by the drawn-in coolant. Additionally, the coolant compressed by the compression mechanism 4 is designed to be discharged from an outlet chamber 27, which will be described later as the outlet side of the compression mechanism, through an outlet port (not shown) formed in the compression mechanism cover 9.

[0034] The compression mechanism 4 consists of a stationary screw 21 and a movable screw 22. The stationary screw 21 has a disc-shaped mirror plate 23 and a helical turn 24, which has an involute shape or an approximate curved line, resting on the surface (one surface) of the mirror plate 23. The surface of the mirror plate 23, on which the turn 24 is vertically arranged, is attached to the compression mechanism housing 7 as the side of the frame part 7B. An outlet bore 26 is formed in the center of the mirror plate 23 of the stationary screw 21. The outlet bore 26 is connected to the outlet chamber 27 in the compression mechanism cover 9. Reference numeral 28 designates an outlet valve provided in the opening on the rear surface (other surface) of the mirror plate 23 in the outlet bore 26.

[0035] The movable screw 22 is a screw that rotates and turns relative to the stationary screw 21 and integrally comprises a disk-shaped mirror plate 31, a helical turn 32 having an involute shape or an approximate curved line resting on the surface (one surface) of the mirror plate 23, and a hub section 33 shaped to project from the center of the rear surface (other surface) of the mirror plate 31. The movable screw 22 is arranged such that the turn 32 faces the turn 24 of the stationary screw 21, and the two face each other and engage with the projecting direction of the turn 32 as the side of the stationary screw 21, forming a compression chamber 34 between the turns 24 and 32.

[0036] This means that the turn 32 of the movable worm 22 faces the turn 24 of the stationary worm 21 and engages with the turn 24, so that the end face of the turn 32 comes into contact with the surface of the mirror plate 23 and the end face of the turn 24 comes into contact with the surface of the mirror plate 31. The other end of the rotating shaft 14, i.e., the end on the 15 side of the movable worm 22, is provided with a column-shaped drive projection 48, which projects eccentrically to the axial center of the rotating shaft 14. Furthermore, a column-shaped eccentric bushing 36 is attached to the drive projection 48 and arranged eccentrically to the axial center of the rotating shaft 14 at the other end of the rotating shaft 14.

[0037] In this case, the eccentric bushing 36 is attached to the drive projection 48 at a position eccentric to the axial center of the eccentric bushing 36. The eccentric bushing 36 is mounted on the hub section 33 of the movable worm 22. When the rotating shaft 14 rotates together with the rotor 30 of the electric motor 2, the movable worm 22 is configured to rotate relative to the stationary worm 21 without rotating about its axis. Furthermore, reference numeral 49 designates a counterweight attached to the outer circumferential surface of the rotating shaft 14 on the side of the movable worm 22, measured from the front bearing 18.

[0038] Since the movable screw 22 rotates eccentrically relative to the stationary screw, the eccentric direction and contact position of each of the turns 24 and 32 are altered during rotation, and the compression chamber 34, which has drawn in the coolant from the aforementioned intake area 37 on the outside (compression chamber pressure: suction pressure Ps), gradually shrinks as it moves inwards. Consequently, the coolant is compressed and finally expelled through the outlet valve 28 from the central outlet bore 26 into the outlet space 27 as outlet pressure Pd (compression chamber pressure).

[0039] In Fig. Reference numeral 38 is an annular pressure plate. The pressure plate 38 serves to divide a counter-pressure chamber 39 formed on the rear surface of the mirror plate 31 of the movable screw 22 and the suction area 37 as a suction pressure zone outside the compression mechanism 4 in the compression mechanism housing 7. The pressure plate 38 is arranged outside the hub section 33 and is inserted between the frame part 7B and the movable screw 22. Reference numeral 41 is a sealing material that is attached to the rear surface of the mirror plate 31 of the movable screw 22 and bears against the pressure plate 38. The counter-pressure chamber 39 and the suction area 37 are separated by the sealing material 41 and the pressure plate 38.

[0040] Furthermore, reference numeral 42 is a sealing material that is attached to the surface of the frame part 7B on the side of the pressure plate 38, rests against the outer circumferential part of the pressure plate 38 and seals between the frame part 7B and the pressure plate 38.

[0041] Furthermore, the reference number 43 in Fig. 1. A backpressure channel is formed from the compression mechanism cover 9 to the housing of the compression mechanism 7. An opening 44, acting as a pressure-reducing section, is incorporated into the backpressure channel 43. The backpressure channel 43 causes the interior of the outlet chamber 27 (the outlet side of the compression mechanism 4) in the compression mechanism cover 9 and the backpressure chamber 39 to communicate with each other, as indicated by an arrow in Fig. As shown in Figure 1, the back pressure channel 43 is arranged so that the coolant or oil (mainly oil), which has a set outlet pressure reduced through the opening 44, is supplied to the back pressure chamber 39.

[0042] The pressure (back pressure Pm) in the back pressure chamber 39 causes a back pressure load that pushes the movable screw 22 against the stationary screw 21. This back pressure load presses the movable screw 22 against the stationary screw 21 against a pressure reaction force from the compression chamber 34 of the compression mechanism 4, so that the contact between the turns 24 and 32 and the mirror plates 31 and 23 is maintained, thus enabling the compression of the coolant in the compression chamber 34.

[0043] Furthermore, in this embodiment, two counter-pressure bores 51 and 52 are incorporated into the mirror plate 31 of the movable screw 22. The first counter-pressure bore 51 is formed between the turns at a position approximately 90° from the outer end of the turn 32 of the movable screw 22. The second counter-pressure bore 52 (counter-pressure bore) is formed between the turns at a position where the turn 32 is offset by approximately 90° relative to the first counter-pressure bore 51. Fig. 2, Fig. 3, Fig. 4 to Fig. 5).

[0044] These backpressure bores 51 and 52 are bores for pressure regulation, connecting the backpressure chamber 39 on the rear side of the mirror plate 31 of the movable screw 22 and the compression chamber 34 on the front surface of the mirror plate 31. Essentially, if the pressure (backpressure Pm) in the backpressure chamber 39 becomes too high, the connecting bore 51 allows the coolant to escape from the backpressure chamber 39 into the compression chamber 34, thus preventing the backpressure Pm from becoming too high. Furthermore, at this time, the oil in the backpressure chamber 39 is also returned to the compression chamber 34. This is particularly effective when the pressure in the outlet chamber 27 is reduced through the opening 44 in the backpressure channel 43 and introduced into the backpressure chamber 39, as in the embodiment.

[0045] The first counter-pressure bore 51 and the second counter-pressure bore 52 described above are machined at a predetermined position on the mirror plate 31 of the movable screw 22 with a predetermined size (bore diameter). The function of the first counter-pressure bore 51 and the second counter-pressure bore 52 is described below with reference to the Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8 described in detail. The counter-pressure bores 51 and 52 are opened and closed by the turn 24 of the stationary screw 21, while the movable screw 22 rotates and turns (orbits) relative to the stationary screw 21.

[0046] In this embodiment, the first counter-pressure bore 51 is configured in positions and / or dimensions such that it opens within the turn 24 of the stationary worm 21 in a crank angle range (rotation angle of the rotating shaft 14) of 25° to 215° and closes at other crank angles. The crank angle range in which the first counter-pressure bore 51 is open is more limited than the conventional range mentioned above (25° to 230°).

[0047] In contrast, the second counter-pressure bore 52 opens within the turn 32 of the movable screw 22 in a crank angle range of 25° to 175° (first crank angle range). The second counter-pressure bore 52 is then configured in positions and / or dimensions such that, when the crank angle is in the range of 175° to 250°, the second counter-pressure bore 52 is temporarily closed by the turn 24 of the stationary screw 21 and then opens again within the turn 24 of the stationary screw 21 in the crank angle range of 250° to 310° (second crank angle range), closing at other crank angles. That is, the second counter-pressure bore 52 opens twice along the turn 24 of the stationary screw 21. Furthermore, the first crank angle range is more limited than the conventional range mentioned above (25° to 230°).

[0048] This situation is addressed using the Fig. 2, Fig. 3, Fig. 4 to Fig. 5 described. Fig. Figure 2 shows a state in which the crank angle is 0° (0 degrees). In this state, both counter-pressure bores 51 and 52 are closed simultaneously. Fig. Figure 3 shows a state in which the crank angle is 90°. In this state, the first counter-pressure bore 51 opens within the turn 24 of the stationary screw 21, and the second counter-pressure bore 52 opens within the turn 32 of the moving screw 22. Fig. Figure 4 shows a state in which the crank angle is 180°. In this state, the first counter-pressure bore 51 is still open within the turn 24 of the stationary screw 21, but the second counter-pressure bore 52 is closed by the turn 24 of the stationary screw 21. Then it shows Fig. 5 a state in which the crank angle is 270°. In this state, the first counter-pressure bore 51 is closed by the turn 24 of the stationary screw 21, but the second counter-pressure bore 52 extends over the turn 24 of the stationary screw 21 and opens within it.

[0049] Fig. Figure 6 shows the crank angle of the rotating shaft 14 and the opening degrees of the counter-pressure bores 51 and 52. In the figure, a dashed line (intersecting with a solid line between 25° and 175°) indicates the opening degree of the first counter-pressure bore 51, and a solid line indicates the opening degree of the second counter-pressure bore 52. As shown in this figure, the first counter-pressure bore 51 opens in the range of the crank angle from 25° to 215°, and the second counter-pressure bore 52 opens in the range of the crank angle from 25° to 175° (first crank angle range) and in the range from 250° to 310° (second crank angle range).

[0050] Next, the function of the first counter-pressure bore 51 and the second counter-pressure bore 52 will be described with reference to the Fig. 7 and Fig. 8 described. As described above, the crank angle range (25° to 215°) at which the first backpressure bore 51 opens, and the crank angle range (first crank angle range: 25° to 175°) at which the second backpressure bore 52 first opens, are more limited than the conventional range (25° to 230°). Therefore, the time during which both backpressure bores 51 and 52 are open is short. This makes it possible to restrict the amount of coolant and oil flowing from the backpressure chamber 39 into the compression chamber 34. In a low-speed operating condition, as in Fig. As shown in Figure 7, it becomes possible to prevent an increase in the back pressure Pm due to an increase in the compression chamber pressure.

[0051] Since, on the other hand, the second counter-pressure bore 52 is then reopened in the second crank angle range (250° to 310°), the counter-pressure chamber 39 and the compression chamber 34 are connected to each other after the compression chamber pressure has been sufficiently increased. Consequently, the higher compression chamber pressure can be supplied to the counter-pressure chamber 39, and a decrease in the counter-pressure under an operating condition in which the suction pressure Ps becomes low can also be prevented, as shown in Fig. 8 shown.

[0052] According to the present invention and from the foregoing, it follows that, when adjusting the back pressure to a corresponding back pressure Pm under both the low-speed operating condition and the low-suction-pressure operating condition, and when eliminating the inconvenience of excessive pressure of the movable screw 22 against the stationary screw 21 under the low-suction-pressure operating condition, which increases power consumption and leads to an increase in costs, it is also possible to eliminate the inconvenience of the back pressure Pm being reduced under the operating condition in which the suction pressure Ps becomes low, and the force with which the movable screw 22 is pressed against the stationary screw 21 becoming too low, thereby causing a compaction failure.

[0053] In this case, the first counter-pressure bore 51 is opened in the range of the crank angle from 25° to 215°, and the second counter-pressure bore 52 is opened in the range of the crank angles from 25° to 175° and 250° to 310°. It is therefore possible to effectively adjust the counter-pressure Pm to a suitable value.

[0054] If the first counter-pressure bore 51 is located further outwards, thus further limiting the crank angle range in which it opens, the first counter-pressure bore 51 will, for example, open outside the turn 24 of the stationary screw 21 when the crank angle is 0°, and will be in contact with the low-pressure compression chamber 34. However, since in this embodiment the first counter-pressure bore 51 is configured in a position and / or dimension such that, after opening within the turn 24 of the stationary screw 21, it is closed by the turn 24 and does not open outside the turn 24, no such problem arises.

[0055] Furthermore, the above design is extremely suitable for the back pressure channel 43, which connects the outlet side of the compression mechanism 4 with the back pressure chamber 39, and for the scroll compressor 1, in which the opening 44 in the back pressure channel 43 is provided as in the embodiment.

[0056] Furthermore, in this embodiment, the first counter-pressure bore 51 and the second counter-pressure bore 52 are each formed in the mirror plate 31 of the movable screw 22. Only the second counter-pressure bore 52 could be used. Moreover, the numerical values ​​shown in this embodiment are not limited to the invention according to claim 1 and should be adjusted appropriately according to the use, function, and capacity of the scroll compressor.

[0057] Furthermore, the present invention, in one embodiment, is applied to the scroll compressor used in the coolant circuit of a vehicle air conditioning system, but is not limited to this. The present invention is suitable for a scroll compressor used in the respective coolant circuits of various cooling devices. In another embodiment, the present invention is applied to the so-called inverter-integrated scroll compressor, but is not limited to this. The present invention can also be applied to a conventional scroll compressor that is not integrally equipped with an inverter. Description of the reference symbols 1 Scroll compressor 4. Compression mechanism 14 rotating shaft 21 fixed snail 22 movable snails 23, 31 Mirror plate 24, 32 turns 27 Outlet space (outlet side) 34 Compression chamber 39 Counterpressure chamber 43 Back pressure channel 44 Opening (pressure reducing section) 51 first counter-pressure bore 52 second counter-pressure bore

Claims

A scroll compressor (1) with a compression mechanism (4) formed from a stationary screw (21) and a movable screw (22), each arranged on surfaces of mirror plates (23, 31) with mutually facing spiral turns (24, 32), and in which the movable screw (22) is rotated and turned in relation to the stationary screw (21) in order to compress a working fluid in a compression chamber (34) formed between the turns (24, 32) of both screws (21, 22), comprising: a counter-pressure chamber (39) formed in a rear surface of the mirror plate (31) of the movable screw (22); and a first counter-pressure bore (51) and a second counter-pressure bore (52) which are formed in the mirror plate (31) of the movable screw (22) and connect the counter-pressure chamber (39) and the compression chamber (34) together,wherein the first counter-pressure bore (51) is formed in a position and / or dimension in which, through the rotation and rotary movement of the movable screw (22), after the first counter-pressure bore (51) is opened within the turn (24) of the stationary screw (21), the first counter-pressure bore (51) is closed by the turn (24) of the stationary screw (21), and is then not opened outside the turn (24) of the stationary screw (21), and wherein the second counter-pressure bore (52) is formed in a position and / or dimension in which, through the rotation and rotary movement of the movable screw (22), after the second counter-pressure bore (52) is opened within the turn (32) of the movable screw (22) in a first crank angle range,the second counter-pressure bore (52) is temporarily closed by the turn (24) of the stationary screw (21) and then opened within the turn (24) of the stationary screw (21) in a second crank angle range. The scroll compressor (1) according to claim 1, wherein the second counter-pressure bore (52) is opened in a range of crank angles from 25° to 175° and 250° to 310°. The scroll compressor (1) according to claim 1 or 2, wherein the first counter-pressure bore (51) is opened in a range of the crank angle from 25° to 215°. The scroll compressor (1) according to one of claims 1 to 3, comprising a back pressure channel (43) connecting the outlet side of the compression mechanism (4) and the back pressure chamber (39), and a pressure reducing section (44) provided in the back pressure channel (43).

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