JP2010101331A - Rotary compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress vibration accompanying fluctuation of load torque in one rotation. <P>SOLUTION: Annular cylinder chambers (C1, C2) of a cylinder (21) are partitioned by an annular piston (22) into an outer cylinder chamber (C1) and an inner cylinder chamber (C2). The cylinder (21) eccentrically rotates by drive of a motor (30) and each volume of the outer cylinder (C1) and the inner cylinder chamber (C2) changes. A volume ratio Vr of the inner cylinder chamber (C2) with respect to the outer cylinder chamber (C1) is set to about 0.7, and output torque of the motor (30) is changed according to fluctuation of the load torque in one rotation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

    The present invention relates to a rotary compressor, and particularly relates to measures against vibration associated with fluctuations in load torque.

    Conventionally, as a rotary compressor having two cylinder chambers, for example, as disclosed in Patent Document 1, there is a compressor that compresses a refrigerant by a change in volume of a cylinder chamber accompanying an eccentric rotational movement of an annular piston.

    The compressor disclosed in Patent Document 1 includes a cylinder having an annular cylinder chamber and an annular piston disposed in the cylinder chamber. The cylinder is composed of an outer cylinder and an inner cylinder arranged concentrically with each other. That is, a cylinder chamber is formed between the outer cylinder and the inner cylinder, and the cylinder chamber is partitioned into an outer cylinder chamber and an inner cylinder chamber by the annular piston. The annular piston is driven by an electric motor so that the outer peripheral surface is in contact with the inner peripheral surface of the outer cylinder at one point and the inner peripheral surface is in contact with the outer peripheral surface of the inner cylinder at one point. On the other hand, it is comprised so that eccentric rotation motion may be carried out.

    An outer blade is disposed outside the annular piston, and an inner blade is disposed on an extension line of the outer blade on the inner side. The outer blade is inserted into the outer cylinder and is urged inward in the radial direction of the annular piston, and its tip is in pressure contact with the outer peripheral surface of the annular piston. The inner blade is inserted into the inner cylinder and biased toward the radially outer side of the annular piston, and the tip thereof is in pressure contact with the inner peripheral surface of the annular piston. The outer blade and the inner blade divide the outer cylinder chamber and the inner cylinder chamber into a high pressure chamber and a low pressure chamber, respectively. In the compressor, in accordance with the eccentric rotational movement of the annular piston, the fluid is sucked in the low pressure chambers of the cylinder chambers, and the fluid is compressed in the high pressure chambers.

JP-A-6-288358

    However, since the load torque of the drive shaft in one rotation fluctuates in the compressor of Patent Document 1 described above, the rotation speed of the drive shaft and the rotor of the electric motor that drives the drive shaft varies with the load torque variation. There is a problem that the vibration in the tangential direction of the casing that fluctuates and the stator of the electric motor is fixed occurs. In the worst case, the pipe connected to the casing is broken.

    The present invention has been made in view of such a point, and an object of the present invention is to provide a load of one rotation in a rotary compressor in which a cylinder having two cylinder chambers and a piston rotate relatively eccentrically. This is to suppress the occurrence of vibrations associated with torque fluctuations.

    The first invention is a compression mechanism (20, 80) having a cylinder (21, 81a, 81b) having two cylinder chambers (C1, C2, 82a, 82b) and a piston (22, 87a, 87b). The motors (30, 81a, 81b) and the pistons (22, 87a, 87b) are relatively eccentrically rotated to change the volumes of the cylinder chambers (C1, C2, 82a, 82b). , 65). Furthermore, the present invention includes torque control means (50) for changing the output torque of the electric motor (30, 65) in accordance with the fluctuation of the load torque of the compression mechanism (20) during one rotation. .

    In the above invention, as the cylinder (21, 81a, 81b) and the piston (22, 87a, 87b) are relatively eccentrically rotated by the drive of the electric motor (30, 65), the two cylinder chambers ( Each volume of C1, C2, 82a, 82b) changes. In each cylinder chamber (C1, C2, 82a, 82b), as the volume of the low pressure chamber (suction chamber) increases, the fluid is sucked and at the same time the volume of the high pressure chamber (compression chamber) decreases. As a result, the fluid in the high pressure chamber is compressed.

    In one rotation of the compression mechanism (20, 80), the load torque of the electric motor (30, 65) varies according to the rotation angle. That is, in each cylinder chamber (C1, C2, 82a, 82b), the load torque becomes the largest immediately before and after the start of the discharge of the compressed fluid. Therefore, in this state, since the output torque of the electric motor (30, 65) is fixed, the rotational speed of the cylinder (21, 81a, 81b) or the piston (22, 87a, 87b) varies. That is, when the load torque increases, the rotation speed decreases, and when the load torque decreases, the rotation speed increases. This fluctuation in the rotational speed causes tangential vibration of the compressor casing.

    However, in the present invention, the torque control means (50) changes the output torque of the electric motor (30, 65) in accordance with the fluctuation of the load torque in one rotation. Specifically, the output torque of the electric motor (30, 65) is changed so as to decrease as the load torque decreases and increase as the load torque increases. That is, torque control is performed so that the output torque of the electric motor (30, 65) becomes a value commensurate with the load torque. Thereby, the rotational speed of the cylinder (21, 81a, 81b) or the piston (22, 87a, 87b) becomes substantially constant, and the occurrence of vibration of the compressor is suppressed.

    In a second aspect based on the first aspect, the cylinder (21) has an annular cylinder chamber (C1, C2). On the other hand, the piston (22) is housed in the annular cylinder chamber (C1, C2), and the cylinder chamber (C1, C2) is divided into two cylinder chambers, an outer cylinder chamber (C1) and an inner cylinder chamber (C2). An annular piston (22) that divides into two.

    In the above invention, as the cylinder (21) and the annular piston (22 (52)) are relatively eccentrically rotated by driving the electric motor (30), the outer cylinder chamber (C1) and the inner cylinder chamber ( Each volume of C2) changes. In each cylinder chamber (C1, C2), as the volume of the low pressure chamber (suction chamber) increases, the fluid is sucked, and at the same time, the volume of the high pressure chamber (compression chamber) decreases. The fluid in the high pressure chamber is compressed.

    Also in this case, in one rotation of the compression mechanism (20), the load torque of the electric motor (30) varies according to the rotation angle, and the rotational speed of the cylinder (21) or the annular piston (22) varies. Thereby, the vibration of the tangent direction of the casing of a compressor will generate | occur | produce. However, in the present invention, the torque control means (50) changes the output torque of the electric motor (30) in accordance with the fluctuation of the load torque in one rotation. Therefore, the rotational speed of the cylinder (21) or the annular piston (22) becomes substantially constant, and the occurrence of vibration of the compressor is suppressed.

    According to a third aspect, in the second aspect, the volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is 0.6 to 1.0.

    In the above invention, since the volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is set from 0.6 to 1.0, the fluctuation range of the load torque in one rotation is reduced. That is, as shown in FIG. 5, the variation range (variation amount) of the load torque increases as the volume ratio Vr of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) decreases. In particular, when the volume ratio Vr is about 0.6 or less, the fluctuation range of the load torque becomes extremely large.

    By the way, in the torque control of the electric motor (30), the output torque of the electric motor (30) is changed by adjusting the input current, the input voltage and the like to the electric motor (30). For example, when the load torque increases, the input current is increased to increase the output torque of the electric motor (30). When the load torque decreases, the input current is decreased to decrease the output torque of the electric motor (30). Here, in general, the motor (30) is driven more efficiently when the input current and the input voltage are substantially constant. That is, when the fluctuation amount (control amount) of the input current or the like increases, the operation efficiency of the electric motor (30) is significantly reduced.

    However, in the present invention, as described above, by defining the volume ratio Vr of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) within a predetermined range, the variation amount of the load torque in one rotation is reduced. Therefore, in one rotation, the fluctuation amount of the input current and input voltage of the electric motor (30) is reduced. Thereby, the operating efficiency fall of an electric motor (30) is suppressed.

    In a fourth aspect based on the second or third aspect, the electric motor (30) is a brushless DC motor.

    In the above invention, since a brushless DC (direct current) motor is used as the electric motor (30), the operating efficiency of the electric motor (30) is higher than when an AC (alternating current) motor is used. In particular, when torque control is performed during low-speed rotation, where fluctuations in the rotation speed tend to be large, the efficiency drop is large with an AC motor and the operation is practically impossible. Maintained.

    According to a fifth invention, in the second or third invention, the torque control means (50) changes the input current, input voltage, or input current phase of the electric motor (30), and outputs the electric motor (30). It is comprised so that a torque may be changed.

    In the above invention, when the load torque is reduced in one rotation, the output torque of the electric motor (30) is reduced by reducing the input current or the input voltage. When the load torque increases, the output torque of the electric motor (30) increases by increasing the input current or the input voltage. Thereby, the output torque of the electric motor (30) is changed to a value commensurate with the load torque. Further, by adjusting (advancing or delaying) the input current phase, the output torque of the electric motor (30) increases or decreases, and is changed to a value commensurate with the load torque. According to the adjustment of the input current phase, in particular, the followability of the output torque of the electric motor (30) is improved with respect to the load torque that varies rapidly.

    According to a sixth invention, in the second or third invention, the electric motor (30) is connected to a cylinder (21) that rotates relative to a fixed annular piston (22).

    In the above invention, the cylinder (21) is the movable side, and the annular piston (22) is the fixed side. That is, the cylinder (21) rotates eccentrically with respect to the annular piston (22), and fluctuations in the rotational speed of the cylinder (21) are suppressed by the torque control means (50). As a result, the occurrence of vibration due to fluctuations in the rotational speed of the cylinder (21) is suppressed.

    According to a seventh invention, in the second or third invention, the electric motor (30) is connected to an annular piston (22) that rotates relative to a cylinder (21) in a fixed state.

    In the above invention, the cylinder (21) is the fixed side, and the annular piston (52) is the movable side. That is, the annular piston (22) rotates eccentrically with respect to the cylinder (21), and the torque control means (50) suppresses fluctuations in the rotational speed of the annular piston (22). As a result, the occurrence of vibration due to the rotational speed fluctuation of the annular piston (22) is suppressed.

    In an eighth aspect based on the second aspect, the compression mechanism (20) is configured such that one of the outer cylinder chamber (C1) and the inner cylinder chamber (C2) is on the low stage side and the other is on the high stage side. It is configured to perform stage compression.

    In the above invention, first, the low-pressure fluid sucked into the outer cylinder chamber (C1) is compressed into an intermediate-pressure fluid. This intermediate pressure fluid is sucked into the inner cylinder chamber (C2). The intermediate pressure fluid in the inner cylinder chamber (C2) is further compressed into a high pressure fluid. This series of operations is performed in one rotation of the compression mechanism (20), and the load torque of the electric motor (30) varies according to the rotation angle. Also in this case, the torque control means (50) makes the rotation speed of the cylinder (21) or the annular piston (22) substantially constant, and the occurrence of vibrations of the compressor is suppressed.

    According to a ninth aspect, in the eighth aspect, the volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is 0.6 to 0.8.

    In the above invention, since the volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is set from 0.6 to 0.8, the fluctuation range of the load torque in one rotation is reduced. That is, as shown in FIG. 13, when the volume ratio Vr = 0.6 and 0.8 of the inner cylinder chamber (C2) to the outer cylinder chamber (C1), the volume ratio Vr = 0.5 (1.0). Compared to the case, the fluctuation range (variation amount) of the load torque becomes smaller. When the volume ratio Vr = 1.0, the outer cylinder chamber (C1) and the inner cylinder chamber (C2) have the same volume, which is a so-called single-stage compression one-cylinder type. In the present invention, the fluctuation range of the load torque in one rotation is smaller than that of the one-cylinder compression mechanism.

    According to a tenth aspect, in the first aspect, the cylinder (81a, 81b) includes a low-stage first cylinder (81a) and a high-stage second cylinder, both of which have cylinder chambers (82a, 82b). (81b). Meanwhile, the piston (87a, 87b) includes a first rotary piston (87a) housed in a cylinder chamber (82a) of the first cylinder (81a) and a cylinder chamber (82b) of the second cylinder (81b). And a second rotary piston (87b) housed in the housing. Further, the compression mechanism (80) compresses the fluid in two stages between the cylinders (81a, 81b) by the eccentric rotation of the rotary pistons (87a, 87b) by the electric motor (65). It is composed of.

    In the above invention, the compression mechanism (80) constitutes a so-called two-cylinder rotary compression mechanism. In the compression mechanism (80), the rotary pistons (87a, 87b) are eccentrically rotated by driving the electric motor (65). Due to the eccentric rotation of the rotary piston (87a, 87b), the volume of each cylinder chamber (82a, 82b) changes, and the fluid is compressed in two stages between both cylinders (81a, 81b). Specifically, first, the low-pressure fluid sucked into the cylinder chamber (82a) of the first cylinder (81a) is compressed into an intermediate-pressure fluid. This intermediate pressure fluid is sucked into the cylinder chamber (82b) of the second cylinder chamber (82b). The intermediate pressure fluid in the cylinder chamber (82b) is further compressed into a high pressure fluid. This series of operations is performed in one rotation of the compression mechanism (20), and the load torque of the electric motor (30) varies according to the rotation angle. Also in this case, the rotational speed of each rotary piston (87a, 87b) becomes substantially constant by the torque control means (50), and the occurrence of vibration of the compressor is suppressed.

    In an eleventh aspect based on the tenth aspect, the volume ratio of the cylinder chamber (82b) of the second cylinder (81b) to the cylinder chamber (82a) of the first cylinder (81a) is 0.6 to 0.8. It is what is.

    In the above invention, the volume ratio of the cylinder chamber (82b) of the second cylinder (81b) to the cylinder chamber (82a) of the first cylinder (81a) is set from 0.6 to 0.8. The fluctuation range of the load torque is reduced. That is, as shown in FIG. 13, when the volume ratio Vr = 0.6 and 0.8 of the inner cylinder chamber (C2) to the outer cylinder chamber (C1), the volume ratio Vr = 0.5 (1.0). Compared to the case, the fluctuation range (variation amount) of the load torque becomes smaller. .

    In a twelfth aspect based on the tenth or eleventh aspect, the compression mechanism (80) is configured such that the rotational phase of the rotary piston (87a) of the first cylinder (81a) and the rotary piston of the second cylinder (81b) ( The rotational phase of 87b) is configured to be shifted by 180 °.

    In the above invention, when the volume of the cylinder chamber (82a) decreases in the first cylinder (81a) due to the rotation of the rotary piston (87a), the fluid compressed to the intermediate pressure is discharged. At approximately the same timing, in the second cylinder (81b), the volume of the cylinder chamber (82b) is increased by the rotation of the rotary piston (87b), and the intermediate pressure fluid discharged from the first cylinder (81a) is sucked. The The sucked intermediate pressure fluid is further compressed and discharged by the volume reduction of the cylinder chamber (82b) of the second cylinder (81b).

    Therefore, according to the present invention, since the output torque of the electric motor (30, 65) is changed in accordance with the fluctuation of the load torque of the compression mechanism (20, 80) during one rotation, the cylinder (21, 81a, 81b) or fluctuations in the rotational speed of the piston (22, 87a, 87b) can be mitigated. Therefore, it is possible to suppress the occurrence of the compressor vibration due to the rotational speed fluctuation.

    Further, according to the third invention, the volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is regulated within a predetermined range (0.6 to 1.0). The amount of torque fluctuation can be reduced. Thereby, the change amount of the output torque of an electric motor (30) can be made small, and the efficiency fall of an electric motor (30) can be suppressed. As a result, energy saving in the operation of the compressor can be achieved.

    According to the fourth aspect of the invention, since the brushless DC motor is used for the electric motor (30), the efficiency of the electric motor (30) can be increased as compared with the case where an AC motor is used. Therefore, the energy saving operation of the compressor can be further promoted.

    According to the ninth or eleventh invention, in the two-cylinder two-stage compression mechanism, the volume ratio of the high-stage cylinder chamber (C2, 82b) to the low-stage cylinder chamber (C1, 82b) Is defined within a predetermined range (0.6 to 0.8). Therefore, the amount of fluctuation of the load torque in one rotation can be reduced, and a decrease in the efficiency of the electric motor (30, 65) can be suppressed.

It is a longitudinal cross-sectional view which shows the compressor which concerns on Embodiment 1. FIG. 3 is a cross-sectional view showing a compression mechanism according to Embodiment 1. FIG. It is a cross-sectional view which shows operation | movement of the compression mechanism which concerns on Embodiment 1 for every rotation angle of 90 degrees. It is a graph which shows the fluctuation | variation state of the compression torque in 1 rotation. It is a graph which shows the fluctuation state of the compression torque with respect to the volume ratio Vr. It is a graph which shows torque fluctuation ratio with respect to volume ratio Vr, vibration ratio, and motor efficiency fall amount. It is a longitudinal cross-sectional view which shows the compressor which concerns on Embodiment 2. FIG. 6 is a cross-sectional view showing a compression mechanism according to Embodiment 2. FIG. It is a cross-sectional view which shows operation | movement of the compression mechanism which concerns on Embodiment 2 for every rotation angle of 90 degrees. It is a longitudinal cross-sectional view which shows the compressor which concerns on Embodiment 3. FIG. 6 is a transverse sectional view showing a compression mechanism according to a third embodiment. It is a graph which shows the relationship between an operating pressure ratio and compression efficiency based on the volume ratio Vr. It is a graph which shows the fluctuation state of the compression torque with respect to the volume ratio Vr. It is a graph which shows the torque fluctuation ratio with respect to the volume ratio Vr. It is a longitudinal cross-sectional view which shows the compressor which concerns on Embodiment 4. 6 is a cross-sectional view illustrating a compression mechanism according to Embodiment 4. FIG.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

Embodiment 1 of the Invention
The first embodiment is a rotary compressor as shown in FIG. In the compressor (1), a compression mechanism (20) and an electric motor (30) for driving the compression mechanism (20) are housed in a casing (10), and the compressor (1) is configured as a completely sealed type. The compressor (1) is used, for example, in a refrigerant circuit of an air conditioner (air conditioner) to compress the refrigerant sucked from the evaporator and discharge it to the condenser.

    The casing (10) includes a cylindrical barrel (11), and an upper end plate (12) and a lower end plate (13) fixed to the upper end and the lower end of the barrel (11), respectively. Yes. The upper end plate (12) is provided with a suction pipe (14) extending therethrough, and the body (11) is provided with a discharge pipe (15) extending therethrough.

    The compression mechanism (20) includes an upper housing (16) and a lower housing (17) fixed to the casing (10), and a cylinder (21). The cylinder (21) has an annular cylinder chamber (C1, C2) and is provided between the upper housing (16) and the lower housing (17). The upper housing (16) integrally has an annular piston (22) disposed in the cylinder chamber (C1, C2). The cylinder (21) is configured to rotate eccentrically with respect to the annular piston (22). In other words, in this embodiment, the cylinder (21) is movable and the annular piston (22) is fixed, and the cylinder (21) and the annular piston (22) are relatively eccentrically rotated. ing.

    The electric motor (30) is a brushless DC (direct current) motor including a stator (31) and a rotor (32). The stator (31) is disposed below the compression mechanism (20), and is fixed to the body (11) of the casing (10). The rotor (32) is connected to a drive shaft (33) that rotates together with the rotor (32). The drive shaft (33) penetrates the compression mechanism (20) in the vertical direction, and an eccentric portion (33a) is formed at a portion located in the cylinder chamber (C1, C2). The eccentric portion (33a) is formed to have a larger diameter than the other portions, and is eccentric from the axis of the drive shaft (33) by a predetermined amount.

    An oil supply path (not shown) extending in the axial direction is provided inside the drive shaft (33). An oil supply pump (34) is provided at the lower end of the drive shaft (33). The oil pump (34) is configured to pump up the lubricating oil stored in the bottom of the casing (10) and supply it to the sliding portion of the compression mechanism (20) through the oil supply passage of the drive shaft (33).

    The cylinder (21) includes an outer cylinder part (24) and an inner cylinder part (25). The outer cylinder portion (24) and the inner cylinder portion (25) are formed in an annular shape that is coaxial with each other, and are integrally formed by connecting end portions with a mirror plate (26). The annular cylinder chamber (C1, C2) is formed between the inner peripheral surface of the outer cylinder portion (24) and the outer peripheral surface of the inner cylinder portion (25). The eccentric portion (33a) of the drive shaft (33) is slidably fitted inside the inner cylinder portion (25). The cylinder (21) is made of cast steel, aluminum alloy or the like.

    The upper housing (16) and the lower housing (17) are respectively formed with bearing portions (16a, 17a) for rotatably supporting the drive shaft (33). As described above, in the compressor (1) of the present embodiment, the drive shaft (33) penetrates the cylinder chamber (C1, C2) in the vertical direction, and both axial portions of the eccentric portion (33a) have bearing portions (16a , 17a), and a penetrating structure held by the casing (10).

    The annular piston (22) has an outer peripheral surface formed with a smaller diameter than an inner peripheral surface of the outer cylinder portion (24), and an inner peripheral surface formed with a larger diameter than the outer peripheral surface of the inner cylinder portion (25). The annular piston (22) is arranged eccentrically in the annular cylinder chamber (C1, C2), and the cylinder chamber (C1, C2) is divided into an outer cylinder chamber (C1) and an inner cylinder chamber (C2). It is configured to partition. That is, the outer cylinder chamber (C1) is formed between the inner peripheral surface of the outer cylinder portion (24) and the outer peripheral surface of the annular piston (22), and the inner cylinder chamber (C2) is formed in the annular piston (22). It is formed between the inner peripheral surface and the outer peripheral surface of the inner cylinder part (25). The end plate (26) of the cylinder (21) constitutes a first closing member that closes one end of each cylinder chamber (C1, C2), and the upper housing (16) is arranged in addition to each cylinder chamber (C1, C2). The 2nd obstruction | occlusion member which obstruct | occludes an end is comprised.

    The annular piston (22) has an outer peripheral surface that is substantially in contact with the inner peripheral surface of the outer cylinder portion (24) at one point, and the inner peripheral surface is positioned at an inner cylinder portion (25 ) Is substantially in contact with the outer peripheral surface at one point.

    As shown in FIG. 2, the compression mechanism (20) includes a high-pressure chamber (C1-Hp, C2-Hp) and a suction chamber, which are compression chambers for the outer cylinder chamber (C1) and the inner cylinder chamber (C2), respectively. It has a blade (23) that divides into a low-pressure chamber (C1-Lp, C2-Lp). The blade (23) is formed in a rectangular plate shape that penetrates the annular piston (22) and extends in the radial direction of the cylinder chamber (C1, C2), and both ends are formed on the inner peripheral surface of the outer cylinder portion (24) and the inner cylinder. It is being fixed to the outer peripheral surface of a part (25).

    The annular piston (22) is formed in a C-shape that is partly divided so that the blade (23) can pass therethrough. An oscillating bush (27) is provided at a portion where the annular piston (22) is divided. The swing bush (27) is composed of a discharge side bush (27A) and a suction side bush (27B). The discharge side bush (27A) and suction side bush (27B) are on the high pressure chamber (C1-Hp, C2-Hp) side and low pressure chamber (C1-Lp, C2-Lp) side, respectively, with respect to the blade (23). Is located.

    The discharge-side bush (27A) and the suction-side bush (27B) are both formed so that the cross-sectional shape is substantially semicircular and the planes face each other. That is, a blade groove (28) in which the blade (23) slides is formed between the opposing surfaces of both bushes (27A, 27B). The swing bush (27) is configured to swing integrally with the blade (23) and the cylinder (21) with respect to the annular piston (22) while the blade (23) advances and retreats in the blade groove (28). It is configured. In addition, you may form both said bush (27A, 27B) in the integral structure connected with a part instead of another body.

    In the compression mechanism (20), as the drive shaft (33) rotates, the contact points between the annular piston (22), the outer cylinder part (24) and the inner cylinder part (25) are shown in FIG. (D) Move sequentially to the figure. That is, the compression mechanism (20) revolves around the drive shaft (33) without rotation of the outer cylinder portion (24) and the inner cylinder portion (25) by the rotation of the drive shaft (33). It is configured.

    The upper housing (16) is formed with a long hole-like suction port (41) below the suction pipe (14). This suction port (41) penetrates the upper housing (16) in the axial direction, and is located above the low pressure chambers (C1-Lp, C2-Lp) of each cylinder chamber (C1, C2) and the upper housing (16). (Low-pressure space (S1)). The outer cylinder part (24) is formed with a through hole (43) for communicating the suction space (42) and the low pressure chamber (C1-Lp) of the outer cylinder chamber (C1). The annular piston (22) has a through hole (44) for communicating the low pressure chamber (C1-Lp) of the outer cylinder chamber (C1) and the low pressure chamber (C2-Lp) of the inner cylinder chamber (C2). ing.

    The annular piston (22) and the outer cylinder portion (24) are preferably chamfered by chamfering the upper end portion of the portion corresponding to the suction port (41) as shown by a broken line in FIG. In this way, the refrigerant can be efficiently sucked into the low pressure chambers (C1-Lp, C2-Lp).

    Two discharge ports (45) are formed in the housing (16). Each discharge port (45) penetrates the upper housing (16) in the axial direction. The lower ends of the discharge ports (45) are opened to face the high pressure chambers (C1-Hp, C2-Hp) of the cylinder chambers (C1, C2). On the other hand, the upper end of each discharge port (45) communicates with the discharge space (47) via a discharge valve (46) that opens and closes the discharge port (45).

    The discharge space (47) is formed between the upper housing (16) and the cover plate (18). The upper housing (16) and the lower housing (17) are formed with a discharge passage (47a) communicating from the discharge space (47) to the lower space (high pressure space (S2)) of the lower housing (17). Yes.

    On the other hand, the lower housing (17) is provided with a seal ring (29). The seal ring (29) is loaded in the annular groove (17b) of the lower housing (17) and is in pressure contact with the lower surface of the end plate (26) of the cylinder (21). Further, high pressure lubricating oil is introduced into the contact surface between the cylinder (21) and the lower housing (17) in the radially inner portion of the seal ring (29). As a result, the seal ring (29) forms a compliance mechanism that reduces the axial clearance between the lower end surface of the annular piston (22) and the end plate (26) of the cylinder (21) using the pressure of the lubricating oil. is doing.

    By the way, in this embodiment, the volume Vout of the outer cylinder chamber (C1) is larger than the volume Vin of the inner cylinder chamber (C2). Specifically, the volume ratio Vr (Vin / Vout) of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is set to about 0.7. The volume ratio Vr is preferably set to a value between 0.6 and 1.0.

    The compressor (21) includes a controller (50) that is a torque control means for controlling the output torque of the electric motor (30).

    The controller (50) is configured to change the output torque of the electric motor (30) in accordance with the fluctuation of the load torque during one rotation of the compression mechanism (20). The controller (50) receives the rotation angle of the rotor (32) and supplies a current having a value set in advance according to the rotation angle of the rotor (32) to the electric motor (30). That is, the controller (50) changes the output torque of the electric motor (30) by controlling the input current of the electric motor (30). The rotation angle of the rotor (32) is the same as the rotation angle of the drive shaft (33). As the rotation angle of the rotor (32), for example, a value calculated from a value detected by a rotation sensor or an induced voltage or current of the electric motor (30) is used.

    Specifically, the input current is increased at a rotation angle with a large load torque, and the input current is decreased at a rotation angle with a small load torque. Since the output torque of the electric motor (30) is proportional to the input current, if the input current is increased or decreased, the output torque of the electric motor (30) increases or decreases accordingly. Thereby, since the output torque of the electric motor (30) becomes a value commensurate with the load torque, the fluctuation of the rotational speed of the drive shaft (33) during one rotation is suppressed, and the occurrence of vibration is suppressed.

    In the present invention, the output voltage of the electric motor (30) may be changed by controlling the input voltage or the input current phase according to the rotation angle of the rotor (32) instead of the input current. For example, the input voltage is increased at a rotation angle with a large load torque, and the input voltage is decreased at a rotation angle with a small load torque. As a result, the output torque of the electric motor (30) increases or decreases in proportion to the input voltage, and is changed to a value commensurate with the load torque. Further, by advancing or delaying the input current phase, the output torque of the electric motor (30) increases or decreases and is changed to a value commensurate with the load torque. In particular, according to the adjustment of the input current phase, the followability of the output torque of the electric motor (30) is improved with respect to the load torque that fluctuates rapidly.

-Driving action-
Next, the operation of the compressor (1) will be described with reference to the drawings.

    First, when the electric motor (30) is started, the rotation of the rotor (32) is transmitted to the outer cylinder part (24) and the inner cylinder part (25) of the compression mechanism (20) via the drive shaft (33). Thereby, the blade (23) reciprocates (advances and retreats) between the swinging bush (27), and the blade (23) and the swinging bush (27) are integrated to form an annular piston (22 ). The outer cylinder portion (24) and the inner cylinder portion (25) revolve while swinging relative to the annular piston (22), and the compression mechanism (20) performs a predetermined compression operation.

    Specifically, in the outer cylinder chamber (C1), the volume of the low-pressure chamber (C1-Lp) is almost minimized in the state of FIG. 3D, and from here the drive shaft (33) rotates clockwise in the figure. Then, the volume of the low pressure chamber (C1-Lp) increases as the state sequentially changes to the states of FIGS. 3 (A), 3 (B), and 3 (C). As the volume of the low pressure chamber (C1-Lp) increases, the refrigerant is sucked into the low pressure chamber (C1-Lp) through the suction pipe (14), the low pressure space (S1), and the suction port (41). The At this time, the refrigerant is not only directly sucked into the low-pressure chamber (C1-Lp) from the suction port (41), but a part of the refrigerant enters the suction space (42) from the suction port (41), from there through the through hole ( 43) is sucked into the low pressure chamber (C1-Lp).

    When the drive shaft (33) makes one revolution and enters the state of FIG. 3 (D) again, the suction of the refrigerant into the low pressure chamber (C1-Lp) is completed. The low-pressure chamber (C1-Lp) is now a high-pressure chamber (C1-Hp) in which the refrigerant is compressed, and a new low-pressure chamber (C1-Lp) is formed across the blade (23). When the drive shaft (33) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (C1-Lp), while the volume of the high pressure chamber (C1-Hp) decreases, and the high pressure chamber (C1-Hp) The refrigerant is compressed. The high-pressure refrigerant in the high-pressure chamber (C1-Hp) flows out from the discharge port (45) into the discharge space (47), and flows out through the discharge passage (47a) into the high-pressure space (S2).

    In the inner cylinder chamber (C2), the volume of the low-pressure chamber (C2-Lp) is almost the minimum in the state of FIG. 3 (B), from which the drive shaft (33) rotates clockwise in FIG. The volume of the low pressure chamber (C2-Lp) increases as the state sequentially changes to (C), FIG. 3 (D), and FIG. 3 (A). As the volume of the low pressure chamber (C2-Lp) increases, refrigerant is sucked into the low pressure chamber (C2-Lp) through the suction pipe (14), the low pressure space (S1), and the suction port (41). The At this time, the refrigerant is not only directly sucked into the low-pressure chamber (C2-Lp) from the suction port (41), but part of the refrigerant enters the suction space (42) from the suction port (41), from there through the through hole ( 43), sucked into the low pressure chamber (C2-Lp) of the inner cylinder chamber (C2) through the low pressure chamber (C1-Lp) and the through hole (44) of the outer cylinder chamber.

    When the drive shaft (33) makes one revolution and returns to the state of FIG. 3 (B), the suction of the refrigerant into the low pressure chamber (C2-Lp) is completed. The low-pressure chamber (C2-Lp) is now a high-pressure chamber (C2-Hp) in which the refrigerant is compressed, and a new low-pressure chamber (C2-Lp) is formed across the blade (23). When the drive shaft (33) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (C2-Lp), while the volume of the high pressure chamber (C2-Hp) decreases, and the high pressure chamber (C2-Hp) The refrigerant is compressed. The high-pressure refrigerant in the high-pressure chamber (C2-Hp) flows out from the discharge port (45) into the discharge space (47), passes through the discharge passage (47a), and flows out into the high-pressure space (S2).

    As described above, the high-pressure refrigerant compressed in the outer cylinder chamber (C1) and the inner cylinder chamber (C2) and flowing into the high-pressure space (S2) is discharged from the discharge pipe (15) and is condensed and expanded in the refrigerant circuit. After going through the stroke and the evaporation stroke, it is sucked into the compressor (1) again.

    Next, the torque control operation of the electric motor (30) will be described. Here, in FIG. 3, (A) shows a state with a rotation angle of 180 °, (B) shows a state with a rotation angle of 270 °, and (C) shows a state with a rotation angle of 0 ° (360 °). It is assumed that D) indicates a state where the rotation angle is 90 °.

    In the above operation, the compression torque (load torque) during one rotation of the drive shaft (33) varies as shown by the solid line in FIG. That is, in the case of the compressor (1) of the present embodiment, the compression torque becomes maximum near the rotation angle of 180 °, and the compression torque becomes minimum near the rotation angles of 90 ° and 270 °. On the other hand, as shown by a broken line in FIG. 4, in the case of a general one-cylinder rotary compressor, the compression torque becomes maximum near a rotation angle of 180 °, and the compression torque becomes minimum near a rotation angle of 0 ° (360 °). Become. Here, when comparing the torque fluctuation width during one rotation (the difference between the maximum and the minimum of the compression torque), the torque fluctuation width (about 1.1 Nm) of the compressor (1) according to the present invention is a one-cylinder rotary compressor. It can be seen that this is significantly smaller than the torque fluctuation range (about 2.3 Nm). Note that the torque fluctuations shown in FIG. 4 are those when the operating pressure ratio (condensation pressure / evaporation pressure) generated in the air conditioner used in the intermediate period is about 1.6.

    The input current of the electric motor (30) is adjusted according to the fluctuation of the compression torque described above. That is, the input current value is maximum at the maximum compression torque and is minimum at the minimum compression torque. Thus, in one rotation of the drive shaft (33), the input current of the electric motor (30) varies from the minimum to the maximum. However, the fluctuation amount (control amount) of the input current is smaller than that in the case of the one-cylinder rotary compressor. That is, in the case of a one-cylinder rotary compressor, since the fluctuation range of the compression torque in one rotation is large, the fluctuation amount of the input current increases accordingly.

    In general, the smaller the amount of fluctuation in the input current, the better the electric motor (the smaller the amount of decrease in efficiency). For this reason, even when the same torque control is performed, the compressor (1) according to the present invention requires less reduction in the efficiency of the electric motor (30) than the one-cylinder rotary compressor. Therefore, the compressor (1) as a whole can perform energy-saving operation.

    Next, the relationship between the volume ratio Vr of the outer cylinder chamber (C1) and the inner cylinder chamber (C2), the torque fluctuation ratio, and the vibration ratio will be described.

    First, FIG. 5 shows the relationship between the volume ratio Vr (Vin / Vout) of the outer cylinder chamber (C1) and the inner cylinder chamber (C2) and the torque fluctuation range. In FIG. 5, the volume ratio Vr (Vin / Vout) is 50/50 = 1, 40/60 = 0.66, 25/75 = 0.33, 15/85 = 0.17, 0/100 = 0. The torque fluctuation range is shown for these five patterns. The volume ratio Vr (Vin / Vout) = 0/100 indicates a one-cylinder rotary compressor. The torque fluctuations shown in FIG. 5 are those when the operating pressure ratio (condensation pressure / evaporation pressure) generated in the air conditioner performing the rated operation is about 3.

    Specifically, the torque fluctuation range is the largest when the volume ratio Vr = 0/100, and the smallest when the volume ratio Vr = 50/50. That is, it can be seen that the closer the volume ratio Vr is to 1, the smaller the torque fluctuation range. Therefore, the closer the volume ratio Vr is to 1, the smaller the vibration associated with torque fluctuation.

    It can also be seen that the period of the main torque fluctuation (the interval between the two valleys of the main torque fluctuation peak) becomes shorter as the volume ratio Vr approaches 1. For example, the period of the main torque fluctuation with the volume ratio Vr = 50/50 (c in FIG. 5) is shorter than the period of the main torque fluctuation with the volume ratio Vr = 25/75 (b in FIG. 5). The cycle (b in FIG. 5) is shorter than the cycle of main torque fluctuation (volume a) in the volume ratio Vr = 0/100. When the period of the main torque fluctuation becomes longer, vibration is slowly applied, and the amplitude of the vibration increases. In general, the amplitude increases in proportion to the square of the period (= 1 / frequency).

    Here, the relationship among the torque fluctuation ratio, the vibration ratio, and the reduction amount of the motor efficiency (motor efficiency) with respect to the volume ratio Vr is shown in FIG. Here, the torque fluctuation ratio and the vibration ratio indicate the torque fluctuation width and vibration when the volume ratio Vr = 0/100 as “1”, and the torque fluctuation width and vibration for each volume ratio Vr are expressed as ratios, respectively. Is. The amount of reduction in motor efficiency is when the rotational speed fluctuation is suppressed to the maximum by torque control. In FIG. 6, the amount of decrease in motor efficiency (motor efficiency) is indicated by a solid line, the torque fluctuation ratio is indicated by a broken line, and the vibration ratio is indicated by a one-dot chain line.

    Specifically, the torque fluctuation ratio and the vibration ratio both decrease as the volume ratio Vr approaches 1. Further, the amount of decrease in motor efficiency is about 0% when the volume ratio Vr = 1, which is the minimum, and increases as the volume ratio Vr decreases. Further, the degree of decrease in motor efficiency is small when the volume ratio Vr is 1.0 to 0.6, but it can be seen that the degree of decrease in motor efficiency is large when the volume ratio Vr is smaller than 0.6. . Thus, when the volume ratio Vr is between 0.6 and 1.0, torque control can be performed in a range where the reduction in motor efficiency is very small, and vibration can be made smaller than in the case of a one-cylinder rotary compressor.

    As described above, in the compressor (1) of the present embodiment, by controlling the torque of the electric motor (30), the electric motor (30) can be controlled more than when the torque control is performed on the one-cylinder rotary compressor. Efficiency reduction can be suppressed. Further, by setting the volume ratio Vr of the outer cylinder chamber (C1) and the inner cylinder chamber (C2) to about 0.7, torque control is performed in a range where the efficiency reduction amount of the electric motor (30) is small. Vibration can be further suppressed. As a result, vibration of the compressor (1) can be suppressed and energy saving operation can be performed.

    In the present embodiment, since the brushless DC motor having higher efficiency than the AC (alternating current) motor is used as the electric motor (30), the intermediate stage of the air conditioner incorporating the compressor (1) according to the present invention is used. It is possible to maintain high efficiency even at the required low speed operation, and further energy saving can be achieved.

    In addition, since the conventional two-cylinder rotary compressor has two cylinders with a volume ratio Vr of 1: 1, the crank mechanism such as a rotary piston or an eccentric shaft portion is required for each cylinder. However, the compressor (1) of the present invention has a structure in which one cylinder is divided into an outer cylinder chamber (C1) and an inner cylinder chamber (C2) and a common annular piston (22) is provided. It is possible to reduce the cost by using only one.

    Further, when the cylinder (21) is made of an aluminum alloy, the centrifugal force during rotation is reduced, so that vibration can be reduced during high-speed operation, and bending of the drive shaft (33) can be suppressed. Therefore, high efficiency and low vibration operation can be performed in a wide range.

<< Embodiment 2 of the Invention >>
In the second embodiment, as shown in FIGS. 7 and 8, the configuration of the compression mechanism (20) in the first embodiment is changed. That is, this embodiment is configured such that the annular piston (52) is movable and the cylinder (21) is fixed, and the annular piston (52) rotates eccentrically with respect to the cylinder (21).

    The compression mechanism (20) includes an upper housing (16) and a piston body (55). The upper housing (16) is integrally formed with a cylinder (21). The piston body (55) is configured to perform eccentric rotational movement with respect to the cylinder (21). In the present embodiment, the lower housing (17) is omitted.

    The cylinder (21) includes an outer cylinder part (24) and an inner cylinder part (25) formed in an annular shape coaxial with each other. The outer cylinder part (24) and the inner cylinder (25) are provided on the lower surface of the end plate (26) of the upper housing (16). An annular cylinder chamber (C1, C2) is formed between the inner peripheral surface of the outer cylinder portion (24) and the outer peripheral surface of the inner cylinder portion (25).

    The piston body (55) includes an end plate (51), an annular piston (52) and a columnar piston (53) which are integrally provided on the upper surface of the end plate (51). The piston body (55) is made of cast steel or aluminum alloy. The annular piston (52) has an inner diameter larger than the outer diameter of the cylindrical piston (53), and is formed coaxially with the cylindrical piston (53). In the piston body (55), the annular piston (52) is disposed in the annular cylinder chamber (C1, C2), and the cylinder chamber (C1, C2) is separated from the outer cylinder chamber (C1) and the inner cylinder chamber ( C2). That is, the end plate (26) of the upper housing (16) constitutes a first closing member that closes one end of each cylinder chamber (C1, C2), and the end plate (51) of the piston body (55) is set to each cylinder chamber (C1 , C2) constitutes a second closing member for closing the other end. The cylindrical piston (53) is disposed in the inner cylinder part (25).

    Also in this embodiment, the volume Vout of the outer cylinder chamber (C1) is larger than the volume Vin of the inner cylinder chamber (C2), and the volume ratio Vr of the inner cylinder chamber (C2) to the outer cylinder chamber (C1). (Vin / Vout) is set to about 0.7.

    The drive shaft (33) of the electric motor (30) has an eccentric portion (33a) formed at the upper end portion, and the eccentric portion (33a) is connected to the piston body (55). That is, the eccentric portion (33a) of the drive shaft (33) is rotatably fitted in a fitting portion (54) integrally formed in a cylindrical shape on the lower surface of the piston body (55). Thereby, with the rotation of the drive shaft (33), the piston body (55) rotates eccentrically with respect to the cylinder (21).

    Next, the operation of the compressor (1) will be described with reference to FIG. The operation of each cylinder chamber (C1, C2) in this operation is substantially the same as that of the first embodiment.

    That is, in the outer cylinder chamber (C1), the volume of the low-pressure chamber (C1-Lp) is almost the minimum in the state of FIG. 9D, and the drive shaft (33) rotates from here to FIG. The volume of the low-pressure chamber (C1-Lp) increases as the state changes to the state of FIGS. 9B and 9C, and the refrigerant is sucked into the low-pressure chamber (C1-Lp). When the drive shaft (33) rotates once, the low pressure chamber (C1-Lp) becomes a high pressure chamber (C1-Hp), and when the drive shaft (33) rotates further, the high pressure chamber (C1-Hp) The volume is reduced and the refrigerant is compressed.

    On the other hand, in the inner cylinder chamber (C2), the volume of the low-pressure chamber (C2-Lp) is almost minimum in the state shown in FIG. 9B, and the drive shaft (33) rotates from here to FIG. 9C. 9 (D) and FIG. 9 (A), the volume of the low pressure chamber (C2-Lp) increases and the refrigerant is sucked into the low pressure chamber (C2-Lp). When the drive shaft (33) makes one rotation, the low pressure chamber (C2-Lp) becomes a high pressure chamber (C2-Hp), and when the drive shaft (33) further rotates, the high pressure chamber (C2-Hp) The volume is reduced and the refrigerant is compressed.

    Also in this embodiment, the torque control of the electric motor (30) is performed by the controller (50) as in the first embodiment. Therefore, the efficiency reduction of the electric motor (30) can be suppressed and energy saving of the compressor (1) can be achieved as compared with the case where torque control is performed on the one-cylinder compressor.

    Further, when the piston body (55) is formed of an aluminum alloy, as in the first embodiment, vibration and bending of the drive shaft (33) are suppressed during high-speed operation, and high efficiency and low vibration are achieved over a wide range. You can drive. Other configurations, operations, and effects are the same as those of the first embodiment.

<< Embodiment 3 of the Invention >>
In the third embodiment, as shown in FIGS. 10 and 11, the compression mechanism (20) in the first embodiment is configured to compress the refrigerant in two stages. That is, in the compression mechanism (20) of this embodiment, the outer cylinder chamber (C1) constitutes a low-stage compression chamber, and the inner cylinder chamber (C2) constitutes a high-stage compression chamber.

    The compressor (1) is used in a refrigerant circuit that uses carbon dioxide (C02) as a refrigerant and performs a two-stage compression / one-stage expansion cycle, for example. Although this refrigerant circuit is not shown, a compressor (1), a radiator (gas cooler), a receiver, an intermediate cooler, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe. In this refrigerant circuit, the high-pressure refrigerant discharged from the inner cylinder chamber (C2) of the compressor (1) sequentially flows through the radiator, receiver, expansion valve, and evaporator, and the outer cylinder chamber (C1) of the compressor (1) ). On the other hand, the intermediate pressure refrigerant compressed in the outer cylinder chamber (C1) flows into the intermediate cooler, and a part of the liquid refrigerant from the receiver is decompressed and flows in. In this intermediate cooler, the intermediate pressure refrigerant from the outer cylinder chamber (C1) is cooled. The cooled intermediate pressure refrigerant returns to the inner cylinder chamber (C2) and is compressed again. This circulation is repeated, and for example, the indoor air is cooled by an evaporator.

    A suction pipe (14), an inflow pipe (1a), and an outflow pipe (1b) are provided through the body (11) of the casing (10) of the compressor (1). The suction pipe (14) is connected to the evaporator, and the inflow pipe (1a) and the outflow pipe (1b) are connected to the intercooler. The upper end plate (12) of the casing (10) is provided with a discharge pipe (15) therethrough. The discharge pipe (15) is connected to a radiator.

    A cover plate (18) is provided on the upper housing (16) of the compression mechanism (20). In the casing (10), the upper side of the cover plate (18) is formed in the high pressure space (4a), and the lower side of the lower housing (17) is formed in the intermediate pressure space (4b). One end of the discharge pipe (15) is opened in the high pressure space (4a), and one end of the outflow pipe (1b) is opened in the intermediate pressure space (4b).

    An intermediate pressure chamber (4c) and a high pressure chamber (4d) are formed between the upper housing (16) and the cover plate (18), and an intermediate pressure passage (4e) is formed in the upper housing (16). Is formed. The upper housing (16) and the lower housing (17) are formed with pockets (4f) located on the outer periphery of the outer cylinder (24). An inflow pipe (1a) is connected to one end of the intermediate pressure passage (4e), while the pocket (4f) is connected to a suction pipe (14) to form a low-pressure atmosphere of suction pressure.

    A first suction port (41a) penetrating in the radial direction is formed in the outer cylinder (24), and the first suction port (41a) is formed on the right side of the blade (23) in FIG. That is, the first suction port (41a) allows the outer cylinder chamber (C1), the pocket (4f), and the suction pipe (14) to communicate with each other.

    The other end of the intermediate pressure passage (4e) is formed in the second suction port (41b). The second suction port (41b) is formed on the right side of the blade (23), opens to the inner cylinder chamber (C2), and communicates the inner cylinder chamber (C2) and the intermediate pressure space (4b). .

    The upper housing (16) has a first discharge port (45a) and a second discharge port (45b). These discharge ports (45a, 45b) penetrate the upper housing (16) in the axial direction. The first discharge port (45a) has one end opened to the high pressure side of the outer cylinder chamber (C1) and the other end opened to the intermediate pressure chamber (4c). The second discharge port (45b) has one end opened to the high pressure side of the inner cylinder chamber (C2) and the other end opened to the high pressure chamber (4d). A discharge valve (46) that is a reed valve is provided at the outer ends of the first discharge port (45a) and the second discharge port (45b).

    The intermediate pressure chamber (4c) and the intermediate pressure space (4b) communicate with each other through a communication path (4g) formed in the upper housing (16) and the lower housing (17). The high-pressure chamber (4d) communicates with the high-pressure space (4a) through a high-pressure passage formed in the cover plate (18) (not shown).

    Also in this embodiment, the volume Vout of the outer cylinder chamber (C1) is larger than the volume Vin of the inner cylinder chamber (C2), and the volume ratio Vr of the inner cylinder chamber (C2) to the outer cylinder chamber (C1). (Vin / Vout) is set to about 0.7.

    In this compressor (1), when the electric motor (30) is started, the outer cylinder (24) and the inner cylinder (25) revolve while swinging with respect to the annular piston (22) as in the first embodiment. . The compression mechanism (20) performs a predetermined compression operation.

    When the volume of the outer cylinder chamber (C1) increases as the drive shaft (33) rotates, the low-pressure refrigerant is sucked from the suction pipe (14) through the pocket (4f) and the first suction port (42). Is done. Further, when the drive shaft (33) rotates, the volume of the outer cylinder chamber (C1) decreases and the refrigerant is compressed. When the pressure in the outer cylinder chamber (C1) reaches a preset intermediate pressure and the differential pressure from the intermediate pressure chamber (4c) reaches the set value, the discharge valve (46) opens and the intermediate pressure from the outer cylinder chamber (C1) The pressurized refrigerant is discharged into the intermediate pressure chamber (4c) and flows out from the outflow pipe (1b) through the intermediate pressure space (4b).

    On the other hand, when the volume of the inner cylinder chamber (C2) increases with the rotation of the drive shaft (33), the intermediate pressure refrigerant flows from the inflow pipe (1a) to the intermediate pressure passage (4e) and the second suction port (43). ). Further, when the drive shaft (33) rotates, the volume of the inner cylinder chamber (C2) decreases and the refrigerant is compressed. When the pressure in the inner cylinder chamber (C2) reaches a set value when the pressure in the inner cylinder chamber (C2) reaches a set value, the discharge valve (46) opens and high-pressure refrigerant flows from the inner cylinder chamber (C2). It is discharged into the high pressure chamber (4d) and flows out from the discharge pipe (15) through the high pressure space (4a). Thus, in the compressor (1) of the present embodiment, the refrigerant compressed in the outer cylinder chamber (C1) is further compressed in the inner cylinder chamber (C2) and compressed in two stages.

    Here, in general, the air conditioner (inverter air conditioner) is frequently operated in a low pressure ratio region where the operating pressure ratio is about 1.6 to about 2.0. Here, the operating pressure ratio is the ratio of the condensation pressure to the evaporation pressure in the refrigerant circuit.

    As shown in FIG. 12, in the low operating pressure ratio region where the operation frequency is high, the higher the volume ratio Vr of the inner cylinder chamber (C2) to the outer cylinder chamber (C1), the higher the compression efficiency. For example, when the volume ratio Vr is 0.8, the compression efficiency becomes maximum when the operating pressure ratio is around 1.5, and when the volume ratio Vr is 0.6, the compression efficiency becomes maximum when the operation pressure ratio is around 1.9. It becomes. On the other hand, when the volume ratio Vr is 0.5, the compression efficiency is maximized when the operating pressure ratio is around 2.5, and when the operating pressure ratio is about 2.0 or less, the compression efficiency is significantly reduced. That is, when two-stage compression is performed in the outer cylinder chamber (C1) and the inner cylinder chamber (C2), the compression ratio of the entire compression mechanism (20) increases as the volume ratio Vr decreases. If it does so, it will become easy to produce an overcompression loss on the driving | running conditions with a low operating pressure ratio, and compression efficiency will fall.

    Next, FIG. 13 shows the relationship between the volume ratio Vr (Vin / Vout) and the torque fluctuation range, and FIG. 14 shows the relationship between the volume ratio Vr (Vin / Vout) and the torque fluctuation ratio. In these figures, it can be seen that the torque fluctuation range and the torque fluctuation ratio are both smaller when the volume ratio Vr = 0.6 and 0.8 than when the volume ratio Vr = 0.5 and 1. Therefore, vibration is suppressed by the amount of small torque fluctuation. The torque fluctuation ratio is a ratio of the torque fluctuation width for each volume ratio Vr as a ratio, with the torque fluctuation width of the volume ratio Vr = 1 being “1”. 13 and 14 are measured in a state where the operating pressure ratio is about 2.

    The volume ratio Vr = 1 indicates that the volumes of the outer cylinder chamber (C1) and the inner cylinder chamber (C2) are the same. In this case, the refrigerant is not compressed in the outer cylinder chamber (C1), and the inner cylinder chamber (C2). Therefore, compression is performed only by single stage compression instead of two-stage compression. That is, the volume ratio Vr = 1 is substantially the same as in the case where single-stage compression is performed by a conventional one-cylinder rotary compressor. Here, when the volume ratio Vr = 0.5, the torque fluctuation range and the torque fluctuation ratio are larger than Vr = 1. That is, since the vibration is large, it is necessary to suppress the vibration by torque control. As a result, it can be seen that the operation efficiency may be lower than that of the conventional one-cylinder rotary compressor.

    As described above, according to the two-stage compression structure of the present embodiment, by setting the volume ratio Vr of the inner and outer cylinder chambers (C1, C2) to about 0.6 to 0.8, Compared with the compressor, the compression efficiency can be increased and vibration can be suppressed.

<< Embodiment 4 of the Invention >>
In the fourth embodiment, as shown in FIGS. 15 and 16, the two-stage compression structure of the compression mechanism (20) in the third embodiment is changed. That is, in the compression mechanism (20) of the third embodiment, the two cylinder chambers (C1, C2) are formed in the same plane, but the compression mechanism (80) of the present embodiment has two cylinder chambers ( 82a and 82b) are stacked one above the other to form a so-called two-stage rotary compressor.

    Specifically, the compressor (60) of the present embodiment includes a low-stage compression mechanism (80a) and a high-stage compression mechanism (80b) in a casing (61) that is a vertically long and cylindrical sealed container. The compression mechanism (80) and the electric motor (65) are accommodated. In the casing (61), the electric motor (65) is disposed above the compression mechanism (80).

    The casing (61) has a body through which the suction pipe (62) passes and an upper part through which the discharge pipe (63) passes. The discharge pipe (63) has an inlet side bent in the casing (61) and opened in the horizontal direction.

    The electric motor (65) includes a stator (66) and a rotor (67). The stator (66) is fixed to the inner peripheral surface of the casing (61). The rotor (67) is disposed inside the stator (66). A main shaft portion (71) of a drive shaft (70) extending in the vertical direction is connected to the central portion of the rotor (67).

    The drive shaft (70) constitutes a drive shaft. The drive shaft (70) is formed with a first eccentric portion (72) and a second eccentric portion (73) in order from the lower side. The first eccentric part (72) and the second eccentric part (73) are formed to have a larger diameter than the main shaft part (71) and eccentric from the axis of the main shaft part (71). In the first eccentric part (72) and the second eccentric part (73), the eccentric direction with respect to the axial center of the main shaft part (71) is reversed. The height of the first eccentric part (72) is higher than that of the second eccentric part (73).

    In the compression mechanism (80), a rear head (84), a first cylinder (81a), a middle plate (86), a second cylinder (81b), and a front head (83) are laminated in order from the bottom. Configured. A first rotary piston (87a) is housed in the first cylinder (81a). A second rotary piston (87b) is housed in the second cylinder (81b).

    The first cylinder (81a), the first rotary piston (87a), the rear head (84), and the middle plate (86) constitute a low-stage compression mechanism (80a). The second cylinder (81b), the second rotary piston (87b), the front head (83), and the middle plate (86) constitute a high-stage compression mechanism (80b). Each of the low-stage side compression mechanism (80a) and the high-stage side compression mechanism (80b) is composed of an oscillating piston type rotary fluid machine that is a kind of positive displacement fluid machine.

    As shown in FIG. 16, the first rotary piston (87a) of the low-stage compression mechanism (80a) is formed in an annular shape. A first eccentric portion (72) is rotatably fitted in the first rotary piston (87a) of the low-stage compression mechanism (80a). The second rotary piston (87b) of the high stage compression mechanism (80b) is also formed in an annular shape. A second eccentric part (73) is rotatably fitted in the second rotary piston (87b) of the high stage side compression mechanism (80b).

    Each rotary piston (87a, 87b) has an inner peripheral surface in sliding contact with the outer peripheral surface of each eccentric portion (72, 73), and an outer peripheral surface in sliding contact with the inner peripheral surface of each cylinder (81a, 81b). A cylinder chamber (82a, 82b) is formed between the outer peripheral surface of each rotary piston (87a, 87b) and the inner peripheral surface of each cylinder (81a, 81b). Each rotary piston (87a, 87b) has a flat blade (74) projecting from its side surface. Each blade (74) is supported by each cylinder (81a, 81b) via a swinging bush (75) provided between a discharge port (89a, 89b) and a suction port (88a, 88b) described later. ing. Each blade (74) partitions the cylinder chamber (82a, 82b) into a high pressure side and a low pressure side.

    As described above, the compression mechanism (80) is configured such that each rotary piston (87a, 87b) revolves while swinging in the cylinder chamber (82a, 82b) by the rotation of each eccentric part (72, 73). ing. The rotational phases of the rotary pistons (87a, 87b) are shifted from each other by 180 °.

   The first cylinder (81a) of the low-stage compression mechanism (80a) and the second cylinder (81b) of the high-stage compression mechanism (80b) have the same inner diameter. The first rotary piston (87a) of the low-stage compression mechanism (80a) and the second rotary piston (87b) of the high-stage compression mechanism (80b) are formed to have the same outer diameter. The height of the first cylinder (81a) of the low-stage compression mechanism (80a) is higher than that of the second cylinder (81b) of the high-stage compression mechanism (80b).

    An annular intermediate passage (90) is formed in the middle plate (86). The middle plate (86) is formed with a discharge port (89a) for the low-stage compression mechanism (80a). The discharge port (89a) communicates the high pressure side of the first cylinder chamber (82a) of the low stage side compression mechanism (80a) and the intermediate passage (90). On the other hand, the front head (83) is formed with a discharge port (89b) of the high-stage compression mechanism (80b). The discharge port (89b) communicates the high pressure side of the second cylinder chamber (82b) of the high stage compression mechanism (80b) with the space in the casing (61). These discharge ports (89a, 89b) are provided with discharge valves (not shown) that open and close their outlets.

    A suction port (88a) is formed in the first cylinder (81a) of the low-stage compression mechanism (80a). The suction port (88a) penetrates the first cylinder (81a) in the radial direction, and the terminal end opens into the first cylinder chamber (82a). A suction pipe (62) is connected to the suction port (88a). Further, the second cylinder (81b) of the high-stage compression mechanism (80b) is formed with a suction port (88b) continuing from the middle plate (86). The suction port (88b) has a starting end opened to the intermediate passage (90) and a terminal end opened to the second cylinder chamber (82b).

    An oil sump in which lubricating oil is stored is formed at the bottom of the casing (61). At the lower end of the drive shaft (70), a centrifugal oil pump (92) immersed in an oil sump is provided. The oil supply pump (92) is connected to an oil supply passage (91) that extends vertically in the drive shaft (70) and communicates with the low-stage compression mechanism (80a) and the high-stage compression mechanism (80b). . The oil supply pump (92) supplies lubricating oil in the oil reservoir to the sliding portion of the low-stage compression mechanism (80a) and the sliding portion of the high-stage compression mechanism (80b) through the oil supply passage (91). It is configured.

    Also in this embodiment, the volume V1 of the first cylinder chamber (82a) is larger than the volume V2 of the second cylinder chamber (82b), and the first cylinder chamber (82a) of the second cylinder chamber (82b). The volume ratio Vr (V2 / V1) is set to about 0.7.

    In the compressor (60), when the electric motor (65) is started, the rotary pistons (87a, 87b) revolve while swinging in the cylinder chamber (81a, 81b). The compression mechanism (80) performs a predetermined compression operation.

    This compression operation will be described with reference to FIG. In FIG. 16, the rotary piston (87a, 87b) swings clockwise and the rotary piston (87a, 87b) is in contact with the top dead center at a rotation angle of 0 ° and the rotary piston (87a, 87b) is bottom dead. The state in contact with the point is set to a rotation angle of 180 °. First, when the drive shaft (70) is slightly rotated from the rotation angle of 0 °, the contact position of the first rotary piston (87a) and the first cylinder (81a) passes through the opening of the suction port (88a). Then, the refrigerant begins to flow from the suction port (88a) into the first cylinder chamber (82a). The refrigerant continues to flow into the first cylinder chamber (82a) until the rotation angle of the drive shaft (70) reaches 360 °.

    Subsequently, in a state where the inflow of the refrigerant into the first cylinder chamber (82a) is completed (the rotation angle of the drive shaft (70) is 360 °), the drive shaft (70) is slightly rotated, and the first rotary piston (87a ) And the first cylinder (81a) pass through the opening of the suction port (88a), the refrigerant is completely closed in the first cylinder chamber (82a). When the drive shaft (70) further rotates from this state, the refrigerant starts to be compressed. When the pressure of the refrigerant in the first cylinder chamber (82a) exceeds the pressure of the refrigerant in the intermediate passage (90), the discharge valve Open and the intermediate-pressure refrigerant is discharged from the discharge port (89a) to the intermediate passage (90). The discharge of the refrigerant continues until the rotation angle of the drive shaft (70) reaches 360 °.

    On the other hand, in the high-stage compression mechanism (80b), the intermediate pressure refrigerant in the intermediate passage (90) flows from the suction port (88b) into the second cylinder chamber (82b) as the drive shaft (70) rotates. That is, when the contact position between the second rotary piston (87b) and the second cylinder (81b) passes through the opening of the suction port (88b), the refrigerant flows into the second cylinder chamber (82b) from the intermediate passage (90). start. The intermediate pressure refrigerant continues to flow into the second cylinder chamber (82b) until the rotation angle of the drive shaft (70) reaches 360 °.

    Subsequently, when the contact position between the second rotary piston (87b) and the second cylinder (81b) passes through the opening of the suction port (88b) and the refrigerant is completely closed in the second cylinder chamber (82b), Starts to be compressed. When the pressure of the refrigerant in the second cylinder chamber (82b) exceeds the pressure of the refrigerant in the space in the casing (61), the discharge valve opens and the high-pressure refrigerant flows into the casing (61) from the discharge port (89b). It is discharged into the space. The discharge of the refrigerant continues until the rotation angle of the drive shaft (70) reaches 360 °. The refrigerant discharged to the space in the casing (61) is discharged from the discharge pipe (63) to the refrigerant circuit. As described above, in the compressor (60) of the present embodiment, the refrigerant compressed in the first cylinder chamber (82a) on the lower stage side is further compressed in the second cylinder chamber (82b) on the higher stage side to be two-staged. Compressed.

    Also in the present embodiment, as in the third embodiment, the relationship between the volume ratio Vr (V2n / V1) and the torque fluctuation range and the relationship between the volume ratio Vr (V2 / V1) and the torque fluctuation ratio are shown in FIGS. 14 is obtained. That is, the torque fluctuation range and the torque fluctuation ratio are both smaller when the volume ratio Vr = 0.6 and 0.8 than when the volume ratio Vr = 0.5 and 1. Therefore, vibration is suppressed by the amount of small torque fluctuation. Therefore, even in the two-stage compression structure in which the low-stage and high-stage cylinder chambers (82a, 82b) are stacked one above the other, the volume ratio Vr of the cylinder chambers (82a, 82b) is 0.6 to 0.8. By setting the degree, the compression efficiency can be increased and vibration can be suppressed as compared with the conventional one-cylinder compressor.

    As described above, the present invention is useful as a rotary compressor having two cylinder chambers whose volumes change due to eccentric rotation of the piston.

1,60 compressor
20 Compression mechanism
21 cylinders
22 Annular piston (piston)
30 electric motor
50 Controller (Torque control means)
C1 Outer cylinder chamber (cylinder chamber)
C2 Inner cylinder chamber (cylinder chamber)
65 Electric motor
80 Compression mechanism
81a First cylinder (cylinder)
81b Second cylinder (cylinder)
82a 1st cylinder chamber (cylinder chamber)
82b Second cylinder chamber (cylinder chamber)
87a First rotary piston (piston)
87b Second rotary piston (piston)

Claims (12)

A compression mechanism (20,80) having a cylinder (21,81a, 81b) having two cylinder chambers (C1, C2,82a, 82b) and a piston (22,87a, 87b);
The motors (30, 81a, 81b) and pistons (22, 87a, 87b) are relatively eccentrically rotated to change the volumes of the cylinder chambers (C1, C2, 82a, 82b). 65)
Torque control means (50) for changing the output torque of the electric motor (30, 65) in response to fluctuations in the load torque of the compression mechanism (20) during one rotation. Machine. In claim 1,
While the cylinder (21) has an annular cylinder chamber (C1, C2),
The piston (22) is housed in the annular cylinder chamber (C1, C2), and the cylinder chamber (C1, C2) is divided into two cylinder chambers, an outer cylinder chamber (C1) and an inner cylinder chamber (C2). A rotary compressor characterized by being an annular piston (22). In claim 2,
A rotary compressor characterized in that a volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is 0.6 to 1.0. In claim 2 or 3,
The electric motor (30) is a brushless DC motor, and is a rotary compressor. In claim 2 or 3,
The torque control means (50) is configured to change an output torque of the electric motor (30) by changing an input current, an input voltage or an input current phase of the electric motor (30). Type compressor. In claim 2 or 3,
The rotary compressor according to claim 1, wherein the electric motor (30) is connected to a cylinder (21) that rotates relative to a fixed annular piston (22). In claim 2 or 3,
The electric motor (30) is connected to an annular piston (22) that rotates relative to a fixed cylinder (21). In claim 2,
The compression mechanism (20) is configured to compress the fluid in two stages, with one of the outer cylinder chamber (C1) and the inner cylinder chamber (C2) as a low-stage side and the other as a high-stage side. Rotary compressor to do. In claim 8,
A rotary compressor characterized in that a volume ratio of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is 0.6 to 0.8. In claim 1,
The cylinders (81a, 81b) are both constituted by a low-stage first cylinder (81a) and a high-stage second cylinder (81b) each having a cylinder chamber (82a, 82b).
The pistons (87a, 87b) are accommodated in the first rotary piston (87a) accommodated in the cylinder chamber (82a) of the first cylinder (81a) and in the cylinder chamber (82b) of the second cylinder (81b). The second rotary piston (87b),
The compression mechanism (80) is configured to compress the fluid between the cylinders (81a, 81b) in two stages by rotating the rotary pistons (87a, 87b) eccentrically by the electric motor (65). A rotary compressor characterized by being made. In claim 10,
The rotary compressor characterized in that the volume ratio of the cylinder chamber (82b) of the second cylinder (81b) to the cylinder chamber (82a) of the first cylinder (81a) is 0.6 to 0.8. In claim 10 or 11,
The compression mechanism (80) is configured such that the rotational phase of the rotary piston (87a) of the first cylinder (81a) and the rotational phase of the rotary piston (87b) of the second cylinder (81b) are shifted by 180 °. A rotary compressor characterized by that.

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