JP2013053579A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in reliability due to an increase in slide loss that is caused by a pressure difference between both sides of a vane at the largest projection of the vane in an operation state of low compression ratio.SOLUTION: A rotary compressor 100 includes a compression mechanism 3, a motor 2, an induction path 14, a return path 16, a shaft 4, a piston 8, the vane 9, an inverter 42 and a control unit 44. The return path 16 returns a working fluid to the induction path 14 from a working chamber 25. A variable capacity mechanism 30 provided in the return path 16 relatively reduces and relatively increases an induction capacity of the compression mechanism 3. The variable capacity mechanism 30 and the inverter 42 are controlled so that a reduction in the induction capacity is compensated with an increase in rotation number of the motor 2. An opening of the return path 16 to the working chamber 25 is disposed within an angle range of 90-360 degrees relative to the vane 9 in a rotation direction of the shaft 4.

Description

  The present invention relates to a rotary compressor.

  The motor of the compressor is usually controlled by an inverter and a microcomputer. If the number of rotations of the motor is lowered, the refrigeration cycle apparatus using the compressor can be operated with a sufficiently lower capacity than the rating. Patent Document 1 further provides one technique for operating the refrigeration cycle apparatus with such a low capacity that cannot be realized by inverter control.

  FIG. 10 is a configuration diagram of the air conditioner described in Patent Document 1. The compressor 715, the four-way valve 717, the indoor heat exchanger 718, the pressure reducing device 719, and the outdoor heat exchanger 720 constitute a refrigeration cycle. The cylinder of the compressor 715 is provided with an intermediate discharge port that opens from the start to the middle of the compression stroke. The intermediate discharge port is connected to the suction path of the compressor 715 by a bypass path 723. The bypass 723 is provided with a flow control device 721 and an electromagnetic on-off valve 722. The electromagnetic on-off valve 722 is opened only during operation at a low set frequency. Thereby, the driving | running with a lower capability is attained.

JP-A 61-184365

  By the way, a shortcut for increasing the efficiency of the refrigeration cycle apparatus is to increase the efficiency of the compressor. The efficiency of the compressor is highly dependent on the efficiency of the motor used. Many motors are designed to exhibit the highest efficiency at a rotational speed in the vicinity of a rated rotational speed (for example, 60 Hz). Therefore, if the motor is driven at an extremely low number of revolutions, improvement in the efficiency of the compressor cannot be expected.

  In view of such circumstances, an object of the present invention is to provide a rotary compressor that can exhibit high efficiency even when low capacity is required (when the load is small).

In order to achieve the above object, in Japanese Patent Application No. 2010-222935 (filing date: September 30, 2010) preceding this application,
A cylinder, a piston arranged inside the cylinder such that a working chamber is formed between an outer peripheral surface of the cylinder and an inner peripheral surface of the cylinder, and the working chamber into a suction chamber and a compression-discharge chamber. A compression mechanism having a partition vane;
A shaft having an eccentric portion fitted to the piston;
A motor for rotating the shaft;
A suction path for leading the working fluid to be compressed to the suction chamber;
A return path for returning the working fluid from the working chamber to the suction path;
When the suction volume of the compression mechanism, which is provided in the return path, should be relatively small, the working fluid is allowed to return from the working chamber to the suction path through the return path, and the suction volume is relatively set. A variable volume mechanism that inhibits working fluid from returning from the working chamber to the suction path through the return path when it should be increased;
An inverter for driving the motor;
A control unit that controls the variable volume mechanism and the inverter so as to compensate for a decrease in the suction volume by an increase in the rotation speed of the motor;
A rotary compressor is disclosed.

  According to the above configuration, the rotary compressor can be operated with a relatively small suction volume by returning the working fluid from the working chamber to the suction path using the return path. However, depending on the opening position of the return path with respect to the working chamber, the following phenomenon occurs.

  When the working fluid is returned to the suction path by the variable displacement mechanism, the rotary compressor having the above configuration starts the compression process from the time when the piston passes through the opening of the return path. Therefore, when the opening position of the return path is close to the opening of the suction path, the compression process starts early, and the compression chamber reaches the discharge pressure before the piston reaches the bottom dead center (maximum protruding position of the vane). become. After that, when the piston reaches the bottom dead center, the vane protrudes to the working chamber side most in one cycle of the revolving motion of the piston, and the length held in the vane groove provided in the cylinder is also small. It will be inclined and caught in the range of the gap with the vane groove. Further, since the area where the vane is exposed to the working chamber is the largest, the vane is strongly pressed against the cylinder by the pressure difference acting on both side surfaces of the vane. In addition, when the moving speed of the vane, that is, the revolution speed of the piston is low, the oil film on the side surface of the vane is more likely to be cut. An abnormal noise occurs due to the delay. Therefore, the present inventors propose a configuration for reducing the vane sliding resistance due to the pressure difference at the time of maximum vane protrusion.

  That is, the present invention has the above basic configuration, and a return port that is an opening to the working chamber of the return path is disposed within an angle range of 90 to 360 degrees with respect to the vane in the rotation direction of the shaft. A rotary compressor is provided.

  According to the rotary compressor of the present invention, the rotary compressor can be operated with a normal suction volume, or the rotary compressor can be operated with a smaller suction volume. Further, when operating with a small suction volume, the variable volume mechanism and the inverter are controlled so that the decrease in the suction volume is compensated by the increase in the rotation speed of the motor. For this reason, high efficiency can be exhibited even when the load is small.

  Furthermore, when the working fluid is returned to the suction path via the return path, the piston that revolves at the start of the compression process passes through the opening of the suction path in the working chamber until it passes the opening of the return path, that is, It can be delayed by 90 degrees or more. That is, it is possible to delay the timing at which the pressure rise in the working chamber starts with respect to the revolution movement of the piston, and accordingly, the timing at which the pressure of the working fluid reaches the discharge pressure is also delayed. As a result, even in the piston bottom dead center position (180 degrees) where the vane is in the maximum projecting state, the discharge pressure does not become in the working chamber. Therefore, since the pressure difference between the working fluids acting on both side surfaces of the vane can be reduced and the sliding resistance between the vane and the cylinder can be reduced, the reliability of the rotary compressor is improved.

The longitudinal cross-sectional view of the rotary compressor which concerns on 1st Embodiment of this invention. 1 is a cross-sectional view taken along line II of the rotary compressor shown in FIG. Operational principle diagram of the rotary compressor shown in FIG. Graph showing the relationship of compression-discharge chamber volume to shaft rotation angle Graph showing the relationship of working fluid compression ratio to shaft rotation angle Control flow chart of variable displacement mechanism (open / close valve) and inverter A longitudinal sectional view of a rotary compressor according to a second embodiment of the present invention. Cross section along line II-II of the rotary compressor shown in FIG. Configuration diagram of a refrigeration cycle apparatus using the rotary compressor of the present embodiment Configuration diagram of conventional air conditioner

(First embodiment)
As shown in FIG. 1, the rotary compressor 100 of this embodiment includes a compressor body 40, an accumulator 12, a discharge path 11, a suction path 14, a return path 16, a variable volume mechanism 30, an inverter 42, and a control unit 44. ing.

  The compressor main body 40 includes a sealed container 1, a motor 2, a compression mechanism 3, and a shaft 4. The compression mechanism 3 is disposed below the sealed container 1. The motor 2 is disposed above the compression mechanism 3 in the sealed container 1. The compression mechanism 3 and the motor 2 are connected by the shaft 4. A terminal 21 for supplying electric power to the motor 2 is provided on the top of the sealed container 1. An oil reservoir 22 for holding lubricating oil is formed at the bottom of the sealed container 1. The compressor body 40 has a so-called hermetic compressor structure.

  The discharge path 11 and the suction path 14 are each composed of a refrigerant pipe. The discharge path 11 penetrates the upper part of the sealed container 1 and is open inside the sealed container 1. The discharge path 11 plays a role of guiding a compressed working fluid (typically a refrigerant) to the outside of the compressor body 40. The suction path 14 has one end connected to the compression mechanism 3 and the other end connected to the accumulator 12, and penetrates the trunk of the sealed container 1. The suction path 14 plays a role of guiding the refrigerant to be compressed from the accumulator 12 to the working chamber 25 of the compression mechanism 3. The return path 16 is mainly composed of a refrigerant pipe. The refrigerant pipe constituting the return path 16 has one end connected to the compression mechanism 3 at a position different from the suction path 14 and the other end connected to the accumulator 12, and penetrates the trunk of the sealed container 1. ing. The return path 16 plays a role of returning the refrigerant once sucked into the working chamber 25 of the compression mechanism 3 to the suction path 14 before compression.

  The compression mechanism 3 is a positive displacement fluid mechanism and is moved by the motor 2 so as to compress the refrigerant. As shown in FIGS. 1 and 2, the compression mechanism 3 includes a cylinder 5, a piston 8, a vane 9, a spring 10, a first closing member 6, and a first closing member 7. Inside the cylinder 5, a piston 8 fitted to the eccentric portion 4 a of the shaft 4 is disposed so that a working chamber 25 is formed between the outer peripheral surface of the cylinder 5 and the inner peripheral surface of the cylinder 5. . A vane groove 24 is formed in the cylinder 5. The vane groove 24 accommodates a vane 9 having a tip that contacts the outer peripheral surface of the piston 8. The spring 10 is disposed in the vane groove 24 so as to push the vane 9 toward the piston 8. The first closing member 6 and the second closing member 7 are respectively arranged on the upper side and the lower side of the cylinder 5 so as to close the working chamber 25 from both sides of the cylinder 5. Moreover, the 1st closure member 6 and the 2nd closure member 7 play the role of the bearing which supports the shaft 4 rotatably. The working chamber 25 between the cylinder 5 and the piston 8 is partitioned by the vane 9, thereby forming a suction chamber 25a and a compression-discharge chamber 25b. The refrigerant to be compressed is guided to the working chamber 25 (suction chamber 25a) through the suction path 14 and the suction port 27 provided in the cylinder 5. A discharge port 29 is formed in the first closing member 6 so that the compressed refrigerant is guided from the working chamber 25 (compression-discharge chamber 25b) to the internal space 28 of the sealed container 1. The discharge port 29 is provided with a discharge valve (not shown). The vane 9 may be integrated with the piston 8. That is, the piston 8 and the vane 9 may be configured as a so-called swing piston.

  The motor 2 includes a stator 17 and a rotor 18. The stator 17 is fixed to the inner peripheral surface of the sealed container 1. The rotor 18 is fixed to the shaft 4 and rotates together with the shaft 4. The shaft 4 is rotated by the motor 2 and the piston 8 is moved inside the cylinder 5. As the motor 2, a motor capable of changing the rotational speed, such as IPMSM (Interior Permanent Magnet Synchronous Motor) and SPMSM (Surface Permanent Magnet Synchronous Motor) can be used.

  The control unit 44 controls the inverter 42 to adjust the rotational speed of the motor 2, that is, the rotational speed of the rotary compressor 100. As the control unit 44, a DSP (Digital Signal Processor) including an A / D conversion circuit, an input / output circuit, an arithmetic circuit, a storage device, and the like can be used.

  The accumulator 12 includes a storage container 12a and an introduction pipe 12b. The storage container 12a has an internal space that can hold a liquid refrigerant and a gas refrigerant. The introduction pipe 12b passes through the upper part of the storage container 12a and opens toward the internal space of the storage container 12a. The suction path 14 and the return path 16 are connected to the accumulator 12 so as to penetrate the bottom of the storage container 12a. The suction path 14 and the return path 16 extend upward from the bottom of the storage container 12a and open toward the internal space of the storage container 12a at a certain height. That is, the return path 16 is connected to the suction path 14 via the internal space of the accumulator 12. It should be noted that another member such as a baffle may be provided inside the storage container 12a in order to reliably prevent the liquid refrigerant from proceeding directly from the introduction pipe 12b to the suction path 14.

  The variable volume mechanism 30 is provided in the return path 16. In the present embodiment, the variable volume mechanism 30 includes an on-off valve 32 and a check valve 35. That is, in this embodiment, the variable volume mechanism 30 does not have the ability to depressurize the refrigerant. Further, the refrigerant sucked into the suction chamber 25a is returned to the suction path 14 through the return path 16 without being substantially compressed in the compression-discharge chamber 25b. Therefore, the decrease in efficiency due to pressure loss is extremely small. However, as long as the efficiency of the rotary compressor 100 is not significantly affected, the variable volume mechanism 30 may have the ability to depressurize the refrigerant.

  The on-off valve 32 is provided in the return path 16 outside the compressor body 40. On the other hand, the check valve 35 is provided inside the compressor body 40. As shown in FIGS. 1 and 2, the return path 16 includes a return port 16p that is an opening to the working chamber 25, and a relay chamber 16h that communicates with the working chamber 25 through the return port 16p. The relay chamber 16h is formed inside the cylinder 5, and the check valve 35 is disposed in the relay chamber 16h. The check valve 35 opens and closes the return port 16p so that the reverse flow of the refrigerant from the relay chamber 16h to the working chamber 25 is prevented. According to the check valve 35, the flow of the refrigerant from the return path 16 to the working chamber 25 can be prevented with a relatively simple structure without relying on electrical control.

  As shown in FIG. 2, the check valve 35 includes a valve body 36, a guide 37 and a spring 38. The valve body 36 is made of a thin metal plate having two surfaces, and the inside of the guide 37 so as to reciprocate between a first position contacting the return port 16p and a second position spaced apart from the return port 16p. Is arranged. One surface of the valve body 36 faces the return port 16p, and the other surface faces the spring 38. The spring 38 is biased toward the return port 16p so as to maintain the valve body 36 in the first position. A gap having an appropriate width is formed between the valve body 36 and the guide 37. The guide 37 supports the valve body 36 that has moved to the second position. When the valve body 36 opens the return port 16p, in other words, when the valve body 36 occupies the second position, the working chamber 25 communicates with the relay chamber 16h of the return path 16. When the valve body 36 closes the return port 16p, in other words, when the valve body 36 occupies the first position, the working chamber 25 is isolated from the relay chamber 16h of the return path 16.

  By making the check valve 35 have such a simple configuration, the cost can be reduced. Moreover, since the pressure loss to the working fluid flowing out to the return path 16 can be suppressed, energy loss due to expansion / recompression can be suppressed.

  The variable volume mechanism 30 plays a role of changing the suction volume (confinement volume) of the rotary compressor 100. When the suction volume of the rotary compressor 100 is to be relatively small, the refrigerant before compression is allowed to return from the working chamber 25 (specifically, the compression-discharge chamber 25b) to the suction passage 14 through the return passage 16. Specifically, the on-off valve 32 is opened. On the other hand, when the suction volume should be relatively increased, the refrigerant before compression is prohibited from returning from the working chamber 25 to the suction path 14 through the return path 16. Specifically, the on-off valve 32 is closed. When the on-off valve 32 is open, the rotary compressor 100 is operated in the low volume mode. When the on-off valve 32 is closed, the rotary compressor 100 is operated in the high volume mode.

  When the operation mode of the rotary compressor 100 is switched from the high volume mode to the low volume mode by controlling the variable volume mechanism 30, the inverter 42 is controlled so as to compensate for the decrease in the suction volume by the increase in the rotation speed of the motor 2. Is done. As a result, even when low capacity is required (when the load is small), the rotational speed of the motor 2 does not have to be extremely reduced. That is, the motor 2 can be driven at a rotational speed that can exhibit high efficiency even when low capacity is required. Therefore, the efficiency of the rotary compressor 100 is also improved.

  As shown in FIG. 2, the relay chamber 16 h and the return port 16 p of the return path 16 are formed at a position of 90 degrees with respect to the vane 9 in the rotation direction of the shaft 4. In the present embodiment, the return port 16 p is provided in the cylinder 5 and opens in the horizontal direction with respect to the working chamber 25. In this specification, the positions of the vanes 9 and the vane grooves 24 are defined as “0 degree” reference positions along the rotation direction of the shaft 4. In other words, the rotation angle of the shaft 4 at the moment when the vane 9 is pushed into the vane groove 24 by the piston 8 to the maximum is defined as “0 degree”.

  In the high volume mode, the process of compressing the refrigerant confined in the compression-discharge chamber 25b (compression process) starts from a rotation angle of 0 degrees. On the other hand, in the low volume mode, the stroke of discharging the refrigerant confined in the compression-discharge chamber 25b from the feedback port 16p is performed in a period of 0 to 90 degrees, and the compression stroke starts from a rotation angle of 90 degrees. When the suction volume in the high volume mode is V, the suction volume in the low volume mode in the present embodiment is 0.85V. Note that the position of the return port 16p can be changed within an angle range of 90 degrees to 360 degrees with respect to the vane 9 in accordance with the ratio of the suction volume to be changed.

  Next, the movement of the compression mechanism 3 will be described with reference to FIG.

  FIG. 3 shows how the shaft 4 and the piston 8 rotate counterclockwise. As the shaft 4 rotates, the volume of the suction chamber 25a increases and sucks the working fluid. As shown in the upper left diagram of FIG. 3, when the shaft 4 makes one rotation, the volume of the suction chamber 25a becomes maximum, and the suction process is completed. Thereafter, the suction chamber 25a changes to the compression-discharge chamber 25b. As the shaft 4 rotates, the volume of the compression-discharge chamber 25b decreases. At this time, if the on-off valve 32 is closed, the compression mechanism 3 is operated in the high volume mode, and the working fluid is compressed and pressurized as the volume of the compression-discharge chamber 25b decreases. On the other hand, when the on-off valve 32 is open, the compression mechanism 3 operates in the low volume mode, and the working fluid passes through the return path 16 without being compressed until the piston 8 passes through the return port 16p. To return to the suction path 14. When the piston 8 passes through the return port 16p, the compression-discharge chamber 25b is isolated from the return port 16p, so that the working refrigerant in the compression-discharge chamber 25b is compressed and increased in pressure as the volume decreases. In either the high volume mode or the low volume mode, the refrigerant is pressurized until reaching the compression ratio in the operating state, and then into the sealed container 1 from the discharge port 29 as the volume of the compression-discharge chamber 25b decreases. And discharged. The discharge stroke is performed until the rotation angle of the shaft 4 reaches 360 degrees (0 degrees). As shown in the lower left diagram and the upper left diagram in FIG. 3, when the shaft 4 rotates once, the volume of the compression-discharge chamber 25 b becomes zero.

  Subsequently, the influence of the high volume mode and the low volume mode in the present embodiment on the sliding state of the working chamber 25 and the vane 9 in actual operation will be described. FIG. 4 shows changes in the volume of the compression-discharge chamber 25b with respect to the rotation angle of the shaft 4, and FIG. 5 shows changes in the compression ratio of the refrigerant in the compression-discharge chamber 25b for each of the high volume mode and the low volume mode. Show.

  The volume of the compression-discharge chamber 25b decreases as the rotation angle of the shaft 4 increases from 0 degree. The volume change speed varies slightly depending on the design parameters of the rotary mechanism, but decreases while drawing a curve that is generally similar to a sine curve. When the rotation angle of the shaft 4 = 0 degree is the maximum volume, and the volume at that time is V, as the rotation angle changes to 90 degrees, 180 degrees, 270 degrees, 360 degrees, It changes to 0.85V, 0.5V, 0.15V, 0.

  As can be seen from FIG. 5, during the operation in the high volume mode, the refrigerant in the compression-discharge chamber 25b starts to be compressed from the time when the rotation angle of the shaft 4 is 0 degree, and when the rotation angle reaches 180 degrees, the compression ratio is V ÷ 0.5V = 2 has been reached. On the other hand, during operation in the low volume mode, the refrigerant in the compression-discharge chamber 25b is not compressed until the rotation angle of the shaft 4 reaches 90 degrees, and is returned to the suction path. Compression starts. Since the volume at 90 degrees is 0.85 V, the compression ratio at 180 degrees is 0.85 V ÷ 0.5 V = 1.7.

  In the room air conditioner using R410A as the refrigerant, a condition where the compression ratio is small and the compressor operates at a low speed appears in an intermediate period in which almost no heating capacity is required. The compression ratio under the minimum heating capacity condition is 1.75, which is smaller than the compression ratio 2 at the time when the rotation angle of the shaft 4 is 180 degrees when operated in the high volume mode. In other words, since the compression ratio is small, the pressure in the compression-discharge chamber 25b reaches the discharge pressure at the bottom dead center at which the vane 9 is maximum projected. At this time, the discharge pressure (high pressure) in the compression-discharge chamber 25b and the suction pressure (low pressure) in the suction chamber 25a act on both side surfaces of the vane 9, respectively. Pressed against the wall surface on the 25a side, the sliding resistance becomes stronger.

  However, when the operation is performed in the low volume mode, the compression ratio when the rotation angle of the shaft 4 is 180 degrees is 1.7, which is smaller than the compression ratio 1.75 of the minimum heating capacity condition. That is, the refrigerant pressure in the compression-discharge chamber 25b does not reach the discharge pressure even in the state where the vane 9 protrudes most. Accordingly, since the difference in pressure acting on the side surface of the vane is reduced, the force with which the vane 9 is pressed against the vane groove 24 is reduced, and the sliding loss and wear of the vane 9 are reduced to improve the reliability of the rotary compressor 100. Can be made.

  Although the R410A room air conditioner has been described above as an example, the configuration of the present embodiment exhibits the effect of improving the reliability of the rotary compressor in a wide operating range even in other refrigerants and refrigeration cycle apparatuses.

  Next, the control procedure of the variable volume mechanism 30 (open / close valve 32) and the inverter 42 by the control unit 44 will be described with reference to FIG.

  In step S1, the number of rotations of the motor 2 is adjusted according to the requested capacity. Specifically, the rotation speed of the motor 2 is adjusted so that a necessary refrigerant flow rate is obtained. Next, in step S2 and step S6, it is determined whether the rotational speed of the motor 2 has been reduced or increased. If the process of reducing the rotational speed is being performed in step S1, the process proceeds to step S3 to determine whether the current rotational speed is 30 Hz or less. If the current rotational speed is 30 Hz or less, it is determined in step S4 whether the on-off valve 32 is closed. When the on-off valve 32 is closed, in step S5, a process of opening the on-off valve 32 and a process of increasing the rotational speed of the motor 2 to twice the current rotational speed are executed. The order of the processes in step S5 is not particularly limited, but the rotational speed of the motor 2 can be increased almost simultaneously with opening the on-off valve 32.

  On the other hand, when the process for increasing the rotational speed is performed in step S1, the process proceeds to step S7 to determine whether the current rotational speed is 70 Hz or higher. If the current rotational speed is 70 Hz or higher, it is determined in step S8 whether the on-off valve 32 is open. If the on-off valve 32 is open, a process of closing the on-off valve 32 and a process of reducing the rotational speed of the motor 2 to 1/2 the current rotational speed are executed in step S9. The order of the processes in step S9 is not particularly limited, but the rotational speed of the motor 2 can be reduced almost simultaneously with closing the on-off valve 32.

  The vane 9 of the present embodiment is preferably provided with a coating or surface treatment for improving lubricity or reducing frictional force on the surface sliding with the vane groove 24. For example, a coating such as diamond-like carbon (DLC) or chromium nitride (CrN), a dimple process, or a nitriding process is suitable.

(Second Embodiment)
FIG. 7 is a longitudinal sectional view of a rotary compressor 200 of the second embodiment, and FIG. 8 is a transverse sectional view thereof. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals.

  In the present embodiment, the relay chamber 16 h and the return port 16 p are provided in the second closing member 7 positioned below the cylinder 5, and the relay chamber 16 h and the return path 16 extend across the second closing member 7 and the cylinder 5. There is provided a communication path 16c that communicates with the refrigerant pipe constituting the. Further, a counterbore 71 is provided on the upper end surface of the second closing member 7 in contact with the piston 8 so as to expand the return port 16 p along the working chamber 25. The counterbore 71 extends from the return port 16p in the rotation direction of the shaft 4, and a part 71a of the edge of the counterbore 71 is formed in an arc substantially equal to the outer diameter of the piston 8, and the piston 8 is formed in the counterbore 71. Coincides with the contour of the piston 8.

  In the present embodiment, a check valve 50 including a reed valve 51 and a valve stop 52 is disposed in the relay chamber 16h. The check valve 50 constitutes the variable volume mechanism 30 together with the on-off valve 32, and allows the flow out from the working chamber 25 to the return path 16 via the return port 16p, and from the return path 16 to the working chamber 25. Block the flow into the water. The reed valve 51 is elastically deformable and opens and closes the return port 16p. The valve stop 52 regulates deformation of the reed valve 51.

  By providing the return port 16p on the end face of the second closing member 7, the return port 16p can be formed by machining in the axial direction, so that the machining accuracy can be improved and the cost can be reduced.

  The return port 16p is opened and closed by the piston 8. However, since the shape of the return port 16p and the shape of the piston 8 are different, the return port 16p is gradually closed immediately before the return port 16p is closed. . For this reason, during operation in the low volume mode, the working fluid continues to flow out to the return path 16 with the return port 16p closed halfway. It will be in a state of being closed earlier than expected. For this reason, the timing at which the compression stroke of the working fluid starts is also advanced, so that the increase in the compression ratio may be accelerated. On the other hand, in this embodiment, the edge 71a of the counterbore 71 is formed in an arc that is substantially equal to the outer diameter of the piston 8, so that the working fluid flow path is made large until immediately before closing, and at the moment of closing, The flow path can be closed rapidly. Therefore, the object of this configuration can be achieved without advancing the timing of increasing the compression ratio.

  The return port 16p is arranged to open upward in the vertical direction from the relay chamber 16h toward the working chamber 25. By doing so, during operation in the high volume mode, the lubricating oil is accumulated in the space formed by the return port 16p and the reed valve 51, and the dead volume can be reduced. Therefore, the volumetric efficiency can be reduced and the compression loss due to the dead volume can be reduced, so that the high efficiency of the rotary compressor can be achieved. The reed valve 51 may open slightly due to pressure overshoot at the moment when the inside of the working chamber 25 reaches the discharge pressure during the high volume mode operation, but according to the rotary compressor of this configuration, the working chamber 25 Since the return port 16p is isolated from the compression-discharge chamber 25b before the discharge pressure is reached, the lubricating oil can be held without the reed valve 51 being opened.

  Further, the return port 16p is arranged so that the inner peripheral surface of the cylinder 5 crosses the return port 16p. By doing so, a lateral space is formed by the cylinder 5, the return port 16p, and the reed valve 51, and the dead volume can be reduced by holding the lubricating oil in this space. Therefore, the performance in the high volume mode of the rotary compressor is improved.

  Further, by configuring the check valve 50 provided in the return path 16 with the reed valve 51 and the valve stop 52, the variable volume mechanism 30 can be realized with a relatively simple configuration. Furthermore, since the configuration of the check valve by the reed valve and the valve stop is also adopted in the discharge mechanism of a general rotary compressor, it is possible to divert existing parts and reduce costs. Use of components with established reliability leads to high reliability of the rotary compressor 200.

  The relay chamber 16h, the return port 16p, and the counterbore 71 may be provided in the first closing member 6 positioned above the cylinder 5.

(Application embodiment)
As shown in FIG. 9, a refrigeration cycle apparatus 600 can be constructed using the rotary compressor 100. The refrigeration cycle apparatus 600 includes a rotary compressor 100, a radiator 602, an expansion mechanism 604, and an evaporator 606. These devices are connected in the above order by refrigerant pipes so as to form a refrigerant circuit. The radiator 602 is configured by, for example, an air-refrigerant heat exchanger, and cools the refrigerant compressed by the rotary compressor 100. The expansion mechanism 604 is composed of, for example, an expansion valve, and expands the refrigerant cooled by the radiator 602. The evaporator 606 is composed of, for example, an air-refrigerant heat exchanger, and heats the refrigerant expanded by the expansion mechanism 604. Instead of the rotary compressor 100 of the first embodiment, the rotary compressor 200 of the second embodiment may be used.

  In the first and second embodiments, the vertical rotary compressors 100 and 200 in which the shaft 4 extends in the vertical direction have been described. However, the rotary compressor of the present invention has a horizontal type in which the shaft 4 extends in the horizontal direction. It may be.

  The rotary compressor of the present invention may be of a two-stage type in which a compression mechanism having a constant suction volume is combined with the compression mechanism 3 to which one end of the return path 16 is connected.

  Furthermore, the variable volume mechanism 30 does not necessarily need to include a check valve, and may be configured only by the on-off valve 32.

  INDUSTRIAL APPLICATION This invention is useful for the compressor of the refrigerating-cycle apparatus which can be utilized for a water heater, a warm water heating apparatus, an air conditioning apparatus etc. The present invention is particularly useful for a compressor of an air conditioner that requires a wide range of capabilities.

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Motor 3 Compression mechanism 4 Shaft 5 Cylinder 6 1st obstruction | occlusion member 7 2nd obstruction | occlusion member 8 Piston 9 Vane 12 Accumulator 14 Suction path 16 Return path 16p Return port 16h Relay room 25 Actuation room 25a Suction room 25b Compression-discharge Chamber 30 Variable volume mechanism 32 On-off valve 35, 50 Check valve 40 Compressor body 42 Inverter 44 Control unit 71 Counterbore 100, 200 Rotary compressor

Claims (8)

A cylinder, a piston arranged inside the cylinder such that a working chamber is formed between an outer peripheral surface of the cylinder and an inner peripheral surface of the cylinder, and the working chamber into a suction chamber and a compression-discharge chamber. A compression mechanism having a partition vane;
A shaft having an eccentric portion fitted to the piston;
A motor for rotating the shaft;
A suction path for leading the working fluid to be compressed to the suction chamber;
A return path for returning the working fluid from the working chamber to the suction path;
When the suction volume of the compression mechanism, which is provided in the return path, should be relatively small, the working fluid is allowed to return from the working chamber to the suction path through the return path, and the suction volume is relatively set. A variable volume mechanism that inhibits working fluid from returning from the working chamber to the suction path through the return path when it should be increased;
An inverter for driving the motor;
A control unit that controls the variable volume mechanism and the inverter so as to compensate for a decrease in the suction volume with an increase in the rotation speed of the motor,
A rotary port, wherein a return port, which is an opening to the working chamber of the return path, is disposed within an angle range of 90 degrees to 360 degrees with respect to the vane in the rotation direction of the shaft. A first closing member and a second closing member for closing the working chamber from both sides of the cylinder;
The rotary compressor according to claim 1, wherein the return port is provided in the first closing member or the second closing member.   The first closing member or the second closing member is provided with a counterbore so as to expand the return port along the working chamber, and the counterbore is formed when the piston covers the counterbore. The rotary compressor according to claim 2, wherein the rotary compressor has an edge that conforms to the contour of the rotary compressor.   The rotary compressor according to claim 2 or 3, wherein the return port is disposed so that the inner peripheral surface of the cylinder crosses the return port.   The rotary compressor according to claim 1, wherein the return port opens upward in the vertical direction with respect to the working chamber. The return path includes a relay chamber that communicates with the working chamber through the return port;
6. The rotary compressor according to claim 1, wherein the variable volume mechanism includes a check valve disposed in the relay chamber to open and close the return port.   The check valve biases the valve body to move between a first position in contact with the return port and a second position spaced from the return port, and to maintain the valve body in the first position. The rotary compressor according to claim 6, comprising a spring and a guide that supports the valve body moved to the second position.   The rotary compressor according to claim 6, wherein the check valve includes a reed valve that can be elastically deformed and a valve stop that restricts deformation of the reed valve.

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