Patent Publication Number: US-6213732-B1

Title: Rotary compressor

Description:
FIELD OF THE INVENTION 
     The present invention relates to a compressor used in an air conditioner or the like, and more particularly to a rotary piston type rotary compressor. 
     BACKGROUND OF THE INVENTION 
     The structure of a rolling piston type rotary compressor widely used in the compressor for an air conditioner is known as represented by a longitudinal sectional view in FIG.  8  and lateral sectional view of compression element in FIG.  9 . In FIG.  8  and FIG. 9, the compressor comprises a motor  102  accommodated in an enclosed container  101 , and a compression unit  103  driven by this motor  102 . A drive shaft  106  of the compression unit  103  is coupled to the motor  102 , and is supported by a main bearing  108  and a subsidiary bearing  109  disposed at both sides of a cylinder block  111 . The motor  102  includes a stator  104 , a rotor  105 , and the drive shaft  106 . Inside of the cylinder block  111  incorporating a cylinder  119 , a roller  110  externally fitted to a crank unit  107  eccentric from the main shaft of the drive shaft  106  is disposed closely to the inner wall of the cylinder  119 . Thus, a compression chamber  115  is formed. In a guide groove  112  of the cylinder block  111 , a blade  114  and a spring device  113  for thrusting the leading end of the blade  114  to the roller  110  are disposed, and the compression chamber  115  is divided into the suction side and compression side. In the cylinder block  111 , on the boundary of the blade  114 , a suction port  116  opening to the cylinder  119  and a discharge port  117  are provided. An accumulator  160  for accumulating the low pressure side refrigerant is connected to the suction port  116 . 
     In the rotary compressor in such constitution having one compression chamber  115 , since compression torque fluctuations are significant, vibrations are large and the compressor piping system may be broken. 
     To solve such a problem, as shown in FIG. 10, a rolling piston type rotary compressor having two compression chambers in a cylinder  219  has been proposed. In FIG. 10, a first blade  221  and a first spring device  222  are disposed in a first guide groove  220  provided in a cylinder block  211 , and a second blade  224  and a second spring device  225  are disposed in a second guide groove  223 . Thus, a first compression chamber  226  and a second compression chamber  227  are provided. In the first compression chamber  226 , a first suction port  228  and a first discharge port  229  are opened, and in the second compression chamber  227 , a second suction port  230  and a second discharge port  231  are opened. 
     In the compressor in such constitution having two blades, the relation between the shaft rotating angle and required torque is shown in FIG.  11 . As shown in FIG. 11, the compression torque action range per revolution of a drive shaft  206  is divided into two sections, and the compressor vibrations are reduced to half as compared with the compressor shown in FIG.  8 . This constitution is disclosed in Japanese Laid-open Patent No. 63-208688. 
     On the other hand, the compressor having the first suction port  228  and second suction port  230  in the cylinder block  211  is constituted, for example, as shown in FIG. 12, in which a first accumulator  218  and a second accumulator  214  are disposed at the suction side. 
     To simplify the suction piping system, a constitution as shown in FIG. 13 is proposed in Japanese Laid-open Patent No. 1-249977. In FIG. 13, an accumulator  350  penetrates through a side wall of an enclosed container  301 , and is connected to a suction port  349   a  of a first compression chamber. To a suction port  349   b  of a second compression chamber, the suction port  349   a  is communicating through a communication pipe  363  in the enclosed container  301 . The passage entering the second compression chamber is communicating with the second compression chamber by detour. The communication pipe  363  is composed by evading the bearing boss of a main bearing  334  for supporting a drive shaft  336 . That is, the length of the passage entering the second compression chamber has a path longer than the length of the passage entering the first chamber. Furthermore, the gas leaving the accumulator  350  is divided into two paths to get into the first compression chamber and second compression chamber respectively. In this case, the two divided flows of the gas are not uniform. In such conventional constitution, as mentioned below, there was a first problem relating to the flow of suction gas. 
     The principle of compression of the compressor forming two compression chambers in the cylinder by disposing two blades in one cylinder block is as shown in FIG.  6 . That is, the shaded area in FIG. 6 ( a ) shows the state of maximum suction stroke volume in the compression chamber. The shaded area in FIG. 6 ( b ) shows the compression chamber immediately before closure of the suction port in the state of minimum suction stroke volume in the compression chamber, which is reduced from the state of the maximum suction stroke volume in FIG. 6 ( a ). This decrease in the suction stroke volume means that the suction gas flows back to the suction piping system through the suction port. The shaded area in FIG. 6 ( c ) shows the state of substantial start of compression after closure of the suction port. The shaded area in FIG. 6 ( d ) shows the state of discharge from the compression chamber through suction port and suction valve as a result of elevation of compression chamber pressure. Thus, flow-in and counter-flow of suction gas occur in the suction and compression strokes. Accordingly, the suction route is unevenly divided into two flows as shown in FIG. 13, and the path lengths of two divided flows are different, and in such constitution, therefore, pulsations occurring in the suction passage interfere with each other, thereby resulting in increase of suction passage resistance and significant drop of compression efficiency. 
     There was also a second problem. FIG. 7 shows a pressure state in each cylinder at each compression stroke. In FIG. 7 ( a ), the pressure in the cylinder opposite to the second plate  224  is low on both sides, and the pressure in the cylinder opposite to the first blade  221  is low on one side, and high on the other. Therefore, the roller side leading end of the second blade  224  and the roller  210  contact with each other by both thrusting forces, that is, the thrusting force of the second spring device  225  acting on the second blade  224  and the thrusting force by the differential pressure of the discharge pressure and suction pressure. 
     On the other hand, the roller side leading end of the first blade  221  and the roller  210  contact with each other by the combined thrusting force of the thrusting force of the first spring device  222  acting on the first blade  221 , and the differential thrusting force of the thrusting force by refrigerant gas pressure distribution from the cylinder inside acting on the roller side leading end of the first blade (the thrusting force on the basis of the distribution rate of the compression intermediate pressure and the distribution rate of the suction pressure) and the thrusting force by discharge pressure. The contacting force of the first blade  221  and roller  210  and the contacting force of the blade  1141  and roller  110  in FIG. 9 are equal to each other. 
     In FIG. 7 ( b ), the pressure in the cylinder opposite to the first blade  221  and second blade  224  is low (suction pressure) on both sides. Therefore, the first blade  221  and the roller  210  of the roller side leading end of the second blade  224  contact with each other by receiving the same thrusting force as the second blade  224  in FIG. 7 ( a ). 
     In FIG. 7 ( c ), the pressure in the cylinder opposite to the first blade  221  is low on both sides, and the pressure in the cylinder opposite to the second blade  224  is low on one side and high on the other. Therefore, the roller side leading end of the first blade  221  and the roller  210  contact with each other by receiving the same thrusting force as the blade  224  in FIG. 7 ( a ). The second blade  224  contacts with the roller  210  by receiving the same thrusting force as the first blade  221  in FIG. 7 ( a ). 
     In FIG. 7 ( d ), moreover, the pressure in the cylinder opposite to the first blade  221  and second blade  224  is low (suction pressure) on both sides. Therefore, the first blade  221  and the roller  210  at the roller side leading end of the second blade  224  contact with each other by receiving the same thrusting force as the second blade  224  in FIG. 7 ( a ). 
     That is, from FIG. 7 ( d ) to FIG. 7 ( a ) and FIG. 7 ( b ), in other words, until the crank  207  rotates 180 degrees, the roller side leading end of the second blade  224  and the roller  210  contact with each other by the two thrusting forces, that is, the thrusting force of the second spring device  225  acting on the second blade  224 , and the thrusting force by the differential pressure of discharge pressure and suction pressure. 
     On the other hand, from FIG. 7 ( b ) to FIG. 7 ( c ) and FIG. 7 ( d ), in order words, until the crank  207  rotates 180 degrees, the roller side leading end of the first blade  221  and the roller  210  contact with each other by the both thrusting forces, that is, the thrusting force of the first spring device  222  acting on the first blade  221  and the thrusting force by the differential pressure of discharge pressure and suction pressure. 
     As a result, the first blade  221  and the roller side leading end of the second blade  224  is greater in the contacting force than between the blade  114  and roller  210  in FIG. 7, and the wear occurs earlier than in the rolling piston type rotary compressor of the prior art. As a result, the durability of the first blade  221 , second blade  224  and roller  210  is lowered. 
     SUMMARY OF THE INVENTION 
     A compressor of the invention comprises 
     (a) a motor, 
     (b) a compressing means installed in an enclosed container, the compressing means including 
     (1) a cylinder block having a cylinder with a cylindrical inner side, 
     (2) a roller connected to a drive shaft coupled to the motor, for moving along the inner side of the cylinder, 
     (3) plural blades moving back and forth from the cylinder block into the cylinder, and sliding on the outer side of the roller, and 
     (4) plural compression chambers enclosed by the inner side of the cylinder block, outer side of the roller, and plural blades, each compression chamber of the plural compression chamber having a suction port and a discharge port, 
     (c) a muffler chamber communicating with each suction port of the plural compression chambers, 
     (d) each passage disposed between the each suction port and the muffler chamber, and 
     (d) an external piping communicating with the muffler chamber. 
     In particular, the each passage has nearly the same length mutually. 
     Preferably, the distance between mutually adjacent passages of the passages is equal. 
     Preferably, the roller includes an inside roller, and an outside roller disposed outside of the inside roller, the outer circumference of the inside roller slides on the inner circumference of the outside roller, and the plural blades slide on the outer circumference of the outside roller. 
     In this constitution, the compression efficiency is enhanced, and vibrations of the passage are extremely decreased, and therefore breakage of the piping mechanism can be prevented. 
     Still more, the durability of the blades and roller is extremely enhanced, and an excellent compression efficiency can be maintained for a long period. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of a rolling piston type rotary refrigerant compressor in accordance with an exemplary embodiment of the present invention; 
     FIG. 2 is a partially magnified view of FIG. 1; 
     FIG. 3 is a lateral sectional view along line  3 — 3  in FIG. 1; 
     FIG. 4 is a sectional view of a rolling piston type rotary refrigerant compressor in accordance with a further exemplary embodiment of the present invention; 
     FIG. 5 is a lateral sectional view of a rolling piston type rotary refrigerant compressor showing a further exemplary embodiment of the present invention; 
     FIG. 6 is a diagram useful for explaining the principles of compression of a compressor; 
     FIG. 7 is a diagram useful for explaining the pressure state in each cylinder at each compression stroke of the compressor; 
     FIG. 8 is a longitudinal sectional view of a conventional rolling piston type rotary compressor; 
     FIG. 9 is a lateral sectional view of the compression unit of the compressor shown in FIG. 8; 
     FIG. 10 is a lateral sectional view of a compression unit of another conventional rolling piston type rotary compressor; 
     FIG. 11 is a load torque fluctuation characteristic diagram of the compressor shown in FIG. 10; 
     FIG. 12 is a lateral sectional view of the compressor shown in FIG. 8; and 
     FIG. 13 is an longitudinal sectional view of a further conventional rolling piston type rotary compressor. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, preferred embodiments of the invention are described below. 
     Embodiment 1 
     FIG. 1 is a longitudinal sectional view of rolling piston type rotary refrigerant compressor. In FIG. 1, a motor  2  is installed in the upper part of inside of an enclosed container  1 , and a compression unit  3  is disposed in the lower part. A discharge pipe  49  connecting to an external piping system of the compressor is connected to the upper space of the motor  2 . A muffler chamber  50  communicating with the suction side of the compression unit  3  is disposed outside of the bottom of the enclosed container  1  and a suction pipe  51  is connected to the muffler chamber  50 . The compression unit  3  has a main bearing  8  and a subsidiary bearing  9  internally fixed in the enclosed container  1 , on both sides of a cylinder block  11 . A drive shaft  6  coupled to a rotor  5  of the motor  2  is supported by the main bearing  8  and subsidiary bearing  9 , and a roller  10  is fitted to a crank  7  of the drive shaft  6 . 
     As shown in FIG. 3, a first blade  14  is fitted in a first guide groove  12  provided in the cylinder block  11 , and the leading end of the first blade  14  is pressed to the roller  10  by a first spring device  13 . In a guide groove  23  provided at the opposite side position, a second blade  24  is fitted, and the leading end of the second blade  24  is pressed to the roller  10  by a second spring device  25 . 
     A first suction port  28  and a second suction port  30  opening to a first compression chamber  26  and a second compression chamber  27  partitioned by the first blade  14  and the second blade  24  are disposed at symmetrical positions, forming a notch in the cylinder wall, at the mounting side of the subsidiary bearing  9  of the cylinder block  11 . A first discharge port  29  and a second discharge port  31  are disposed at symmetrical positions at the mounting side of the main bearing  8  of the cylinder block  11 . 
     A first discharge valve device  61 , a second discharge valve device  62 , and a discharge guide  63  are disposed in the main bearing  8 , and form a part is of a discharge refrigerant passage. 
     One end of a first communication pipe  64  communicating with the first suction port  28  is opposite to both first compression chamber  26  and first suction port  28 , and one end of a second communication pipe  65  communicating with the second suction port  30  is opposite to both second compression chamber  27  and second suction port  30 , and other end of the second communication pipe  65  penetrates through the subsidiary bearing  9  and the bottom of the enclose container  1  and communicates with the muffler chamber  50 . The passage of the first compression chamber  26  and muffler chamber  50  has the first communication pipe  64 . The passage of the second compression chamber  27  and muffler chamber  50  has the second communication pipe  65 . 
     Opening ends of the first communication pipe  64  opposite to the first compression chamber  26  and the second communication pipe  65  opposite to the second compression chamber  27  are disposed so as to be opened and closed intermittently by the end of the roller  10 . The first communication pipe  64  and second communication pipe  65  are fixed by silver-alloy brazing between the bottom of the enclosed container  1  and the outer wall of the muffler chamber  50 , so as to support the muffler chamber  50 . 
     The upper space and lower space of a motor compartment  70  for accommodating the motor  2  communicate with each other through a cooling passage  71  provided outside of a stator  4  of the motor  2 . An oil sump  35  communicates with the lower space of the motor compartment  70 . A tiny hole  36  is formed in a part of the suction pipe  51  invading into the muffler chamber  50 . An auxiliary fixing member  73  and a compressor support base  72  are disposed for fixing the enclosed container  1  and the muffler chamber  50 . 
     In thus constituted rolling piston type rotary compressor, the operation is described below. As the drive shaft  6  coupled to the rotor  5  of the motor  2  rotates, according to the principle of compression shown in FIG. 6, the refrigerant gas is sucked and compressed in the first compression chamber  26  and second compression chamber  27 , respectively, and the refrigerant gas runs through the passage of the first discharge valve device  61 , second discharge valve device  62 , main bearing  8  and discharge guide  63 , and is discharged into the motor compartment  70 . Part of lubricating oil contained in the refrigerant gas is separated to return to the oil sump  35 , while the remaining lubricating oil is sent out to outside of the compressor through the discharge pipe  49  together with the refrigerant gas. When the discharge refrigerant gas passes inside the discharge guide  63 , the main bearing  8  is cooled. 
     On the other hand, the refrigerant gas (including lubricating oil) flowing into the muffler chamber  50  from the low pressure side of the refrigerant cycle piping system through the suction pipe  51  collides against the obstruction wall, and then changes its flow direction, and at this time, part of the lubricating oil is separated by the inertial force of the lubricating oil, and then it flows alternately into the suction side of the first compression chamber  26  and second compression chamber  27  through the first communication pipe  64  and second communication pipe  65 . 
     In the first compression chamber  26  and second compression chamber  27 , the suction refrigerant gas in the suction stroke moves in and out of the first communication pipe  64  and second communication pipe  65  by the principle of suction and compression explained in FIG.  6 . Since the first communication pipe  64  and second communication pipe  65  are both short and in the same length, the suction refrigerant gas flowing back in the first communication pipe  64  communicating with the first compression chamber  26  is instantly sucked into the second communication pipe  65  communicating in the suction stroke of the second compression chamber  27  through the muffler chamber  50 . Thus, pulsations of the suction refrigerant gas occurring in the muffler chamber  50  can be suppressed. 
     Incidentally, when the refrigerant gas flows back from the first compression chamber  26  and second compression chamber  27  into the muffler chamber  50 , since the first communication pipe  64  and second communication pipe  65  are designed so as not to change the flow direction of the refrigerant gas (that is, the opening end of the first communication pipe  64  is opposite to both first compression chamber  26  and first suction port  28 , and the opening end of the second communication pipe  65  is opposite to both second compression chamber  27  and second suction pipe  30 ), the passage resistance is extremely small when the refrigerant gas is discharged into the muffler chamber  50  from the first compression chamber  26  and second compression chamber  27 . 
     As a result, when the refrigerant gas flows back in the first communication pipe  64  and second communication pipe  65 , the pressure elevation in the suction stroke in the first compression chamber  26  and second compression chamber  27  is almost zero. By the negative pressure generated when the refrigerant gas passes through the suction pipe  51 , the lubricating oil staying in the bottom of the muffler chamber  50  is sucked up through the tiny hole  36 , and is mixed into the suction refrigerant gas. 
     Thus, according to the exemplary embodiment, a common muffler chamber  50  is installed among the first suction port  28  of the first compression chamber  26 , the second suction port  30  of the second compression chamber  27 , and the external suction piping system of the compressor, and the length of the first communication pipe  64  between the first suction port  28  and the muffler chamber  50  is nearly same as the length of the second communication pipe  65  between the second suction port  30  and the muffler chamber  50 . In this constitution, when part of the refrigerant gas sucked into the first compression chamber  26  and second compression chamber  27  temporarily flows back into the first suction port  28  and second suction port  30 , pulsations occur in the first communication pipe  64  and second communication pipe  65  in the same magnitude at a phase difference of 180 degrees. Accordingly, due to effects of pulsations, the suction efficiency and each compression torque fluctuation of the first compression chamber  26  and second compression chamber  27  occur symmetrically, so that torque fluctuations in one revolution of the drive shaft  6  can be dispersed. As a result, the motor efficiency is enhanced, and vibrations of compressor piping system are reduced. 
     Besides, each pulsation refrigerant gas propagating to the muffler chamber  50  through the first communication pipe  64  and second communication pipe  65  is reduced in the muffler chamber  50 . That is, the refrigerant gas flowing back from the first communication pipe  64  is sucked into the second communication pipe  65  through the muffler chamber  50 , and the refrigerant gas pulsation propagating from the first communication pipe  64  is reduced. As a result, the refrigerant gas pulsation does not propagate to the external suction piping system of the compressor through the suction pipe  51 , so that the vibration of the compressor external suction piping system can be decreased. 
     Moreover, since extreme oversupply of suction refrigerant gas does not occur, excessive compression load can be prevented. 
     Also according to the embodiment, the muffler chamber  50  is installed at the subsidiary bearing  9  side, and the first discharge port  29  and second discharge port  31  are disposed at the main bearing  8  side, and therefore the distance between the main bearing  8  and the motor  2  is short, which is the same as in the conventional rotary compressor, and the bending deformation of the drive shaft  6  is decreased. As a result, the compressor vibration and bearing wear due to imbalance of the rotary driving system are decreased. 
     Still more, since the muffler chamber  50  in the space necessary for absorbing pulsation can be installed in a desired state, the pulsation attenuation effect can be enhanced. 
     Further according to the exemplary embodiment, since the first communication pipe  64  and second communication pipe  65  are disposed by penetrating through the subsidiary bearing  9  in the axial direction, each suction passage to the muffler chamber  50  is shorter, and the magnitude of pulsation is decreased. As a result, the vibration in the external suction piping system of the compressor is reduced, and the compressor suction efficiency can be improved. 
     According to the exemplary embodiment, by disposing the muffler chamber  50  outside of the end wall of the enclosed container  1  at the subsidiary bearing  9  side, penetrating through the end wall of the enclosed container, installing the first communication pipe  64  between the first suction port  28  and muffler chamber  50 , and installing the second communication pipe  65  between the suction port  30  and muffler chamber  50 , the suction passage is shortened, heating of the muffler chamber  50  is prevented, and the compression efficiency is enhanced. 
     According to the exemplary embodiment, moreover, by disposing the muffler chamber  50  outside of the end wall of the enclosed container  1  at the subsidiary bearing  9  side, and disposing first communication pipe  64  and second communication pipe  65  to penetrate through the subsidiary bearing  9  and the end wall of the enclosed container  1 , the suction passage can be further shortened, pulsation occurring inside the communication pipe  64  and communication pipe  65  can be decreased, and heating of suction refrigerant gas can be prevented. 
     In the exemplary embodiment, by holding mainly the muffler chamber  50  in the enclosed container  1  by the first communication pipe  64  and second communication pipe  65  for composing the suction passage, the muffler chamber  50  can be disposed easily in the enclosed container  1 . 
     In the exemplary embodiment, further, since the opening positions of the first communication pipe  64  and second communication pipe  65  to the muffler chamber  50  are nearly symmetrical to the center of the muffler chamber  50 , the pulsation attenuation action in the muffler chamber  50  can be enhanced, and the vibration in the suction piping system can be decreased. 
     Further according to the exemplary embodiment, by disposing the utmost downstream end of the suction pipe  51  connecting to the compressor external suction piping system nearly in the common center to the openings of the first communication pipe  64  and second communication pipe  65  to the muffler chamber  50 , the pulsation attenuation action in the muffler chamber  50  can be further increased, and the compression efficiency is enhanced and the vibration of the suction piping system can be decreased. 
     Embodiment 2 
     FIG. 4 shows a constitution of a refrigerant compressor incorporating a muffler chamber  81  in an enclosed container  80 . The inside of the enclosed container  80  is divided into an upper high pressure space and a lower muffler chamber  81  by means of a partition member  82 . The outer circumference of the partition member  82  is tightly welded to the end of the upper enclosed container  80   a  and the end of the lower enclosed container  80   b . The utmost downstream end of a suction pipe  83  is set at a position higher than the lower end of a first communication pipe  84  communicating with a first suction port  28 , and the lower end of a second communication part  85  communicating with a second suction pipe  30 . Thus, the refrigerant gas flowing into the muffler chamber  81  from the suction pipe  83  is prevented from flowing directly into the first communication pipe  84  and second communication pipe  85  without separating the lubricating oil. The other constitution is the same as in FIG.  1 . 
     According to the exemplary embodiment, by forming the muffler chamber  81  by disposing the partition member  82  between the end wall of the enclosed container  80  and the subsidiary bearing  9 , each suction passage is the shortest, and troubles due to pulsation occurring in each suction passage can be avoided. 
     Also according to the exemplary embodiment, by extending the utmost downstream end of the suction pipe  51  connected to the compressor external suction piping system up to the center of the muffler chamber  50 , and disposing the utmost downstream end above the opening ends of the first communication pipe  64  and second communication pipe  65  to the muffler chamber  50 , the gas-liquid mixed refrigerant gas flowing into the muffler chamber  50  from the external suction piping system of the compressor is prevented from flowing directly into the first compression chamber  26  and second compression chamber  27 . 
     In the exemplary embodiment, moreover, the first blade  14  and second blade  24  are disposed at equal interval in the cylinder block  11 , but the same action and effect are obtained if more blades are disposed at equal interval. 
     Embodiment 3 
     As shown in FIG. 5, a roller  10  is double rollers comprising an inside roller  10   a  and an outside roller  10   b , and the outer circumference of the inside roller  10   a  slides on the inner circumference of the outside roller  10   b . The axial dimension of the inside roller  10   a  is set smaller than the axial direction of the outside roller  10   b  so that oil film may not be formed between the side of the inside roller  10   a  and the side of the main bearing  8  and subsidiary bearing  9 , and hence the lubricating oil supplied into the inside of the inside roller  10   a  may be supplied to the inner circumference of the outside roller  10   b.    
     A first blade  14   a  is fitted to a first guide groove  12  formed in a cylinder block  11   a , and the leading end of the first blade  14   a  is pressed to the outside roller  10   b  by a spring device  13   a . A second blade  24   a  is fitted to a second guide groove  23   a  provided at the opposite side position, and the leading end of the second blade  24   a  is pressed to the outside roller  10   b  by the spring device  13   a.    
     A first suction port  28   a  and a second suction port  30   a  communicating with a first compression chamber  26  and a second compression chamber  27  partitioned by the first blade  14   a  and the second blade  24   a  are opened to the inner circumference of a cylinder  15  provided in the cylinder block  11   a . A first discharge port  29  and a second discharge port  31  are disposed at symmetrical positions to the mounting side of the main bearing  8  of the cylinder block  11   a.    
     In thus constituted rolling piston type rotary refrigerant compressor, the flow of lubricating oil, and operation of the roller  10 , first blade  14   a  and second blade  24   a  are explained below. 
     The lubricating oil supplied into the inside roller  10   a  by pumping means (not shown) assembled in the drive shaft  6  is fed into the outside roller  10   b  through the side of the inside roller  10   a  by the differential pressure of the first compression chamber  26  and second compression chamber  27  and the centrifugal force. 
     The lubricating oil is fed into the inner circumference of the outside roller  10   b  also through an oil hole (not shown) provided penetrating through inside and outside of the inside roller  10   a . By this supply of lubricating oil, the sliding surfaces of the inside roller  10   a  and outside roller  10   b  keep an oil film forming state. 
     The first blade  14   a  and second blade  24   a  obtaining the thrusting force by the lubricating oil pressure and spring device (wire spring)  13   a  in the first guide groove  12  and second guide groove  23  communicating with the oil sump  35  in which the discharge pressure acts are pressed to the outer circumference of the outside roller  10   b . As explained in FIG. 7, the thrusting force to the first blade  12   a  varies with the pressure of the lubricating oil in the first guide groove  12  and the differential pressure in the first compression chamber  26 , while the thrusting force to the second blade  24   a  varies with the pressure of the lubricating oil in the second guide groove  23  and the differential pressure in the second compression chamber  27 . 
     That is, as shown in FIG. 7, the thrusting forces acting on the first blade  12  and second blade  24  are not equal to each other in any timing, and the magnitude of the thrusting forces is exchanged in every half revolution while the drive shaft  6  makes one revolution. 
     The outside roller  10   b  in a form being held from both sides by the first blade  14   a  and second blade  24   a  shown in FIG. 5 is extremely limited in the rotary motion in the rotating direction of the drive shaft  6 . As shown in FIG. 5, the outside roller  10   b  receiving the compressed refrigerant gas pressure in the second compression chamber  27  in the midst of compression slips on the inside roller  10   a  while being supported by the inside roller  10   a . Further, the crank  7  of the drive shaft  6  for supporting the inside roller  10   a  slips on the inside roller  10   a.    
     That is, the leading ends of the crank  7  of the drive shaft  6 , inside roller  10   a , outside roller  10   b , first blade  14   a , and second blade  24   a  slip on each other. As a result, the sliding speed between the outside roller  10   b  and the leading end of the first blade  14   a , and that between the outside roller  10   b  and second blade  24   a  maintain a very low speed, thereby preventing wear of the leading ends of the first blade  14   a  and second blade  24   a . The outer circumference of the outside roller  10   b  rotating at very low speed is coated with the lubricating oil mixed in the refrigerant gas, and along with rotation of the outside roller  10   b , it is gradually supplied up to the leading ends of the first blade  14   a  and second blade  24   a , and wearing is prevented. 
     Thus, according to the embodiment, the roller  10  is double rollers consisting of inside roller  10   a  and outside roller  10   b , and the outer circumference of the inside roller  10   a  slides on the inner circumference of the outside roller  10   b . In this constitution, the inside roller  10   a  sliding on the outer circumference of the crank  7  of the drive shaft  6  slides on the inner circumference of the outside roller  10   b . Moreover, the outside roller  10   b  receives the frictional resistance of the leading ends of the first blade  14   a  and second blade  24   a , causing an extreme slipping against the inside roller  10   a , and slightly rotates. The outside roller  10   b  slips slightly between the leading ends of the first blade  14   a  and second blade  24   a , and the outer circumference of the outside roller  10   b  can decrease the friction of the leading ends of the first blade  14   a  and second blade  24   a.    
     In the embodiment, for rotary motion of the outside roller  10   b , the thrusting force to the first blade  14   a  and second blade  24   a  is set. In this constitution, as the outside roller  10   b  rotates, the lubricating oil adhered to the outer circumference of the outside roller  10   b  is gradually sent into the leading end sliding parts of the first blade  14   a  and second blade  24   a , and is present for lubricating of the leading end sliding parts of the first blade  14   a  and second blade  24   a , so that wear can be decreased. 
     Meanwhile, in the embodiment, the roller  10  consists of the inside roller  10   a  and outside roller  10   b , but the roller  10  may be also composed of three or more rollers, and the same action and effect as in double rollers can be obtained. 
     Similarly, in the embodiment, the first blade  14   a  and second blade  24   a  are disposed in the cylinder  11   a  but three or more blades may be also disposed. In this case, the outside roller  10   b  rotates at an extremely low speed. 
     The foregoing embodiments relate to the refrigerant compressor, but the same action and effect are obtained in the case of other gas compressorsfor compressing other gases (such as oxygen, nitrogen, helium, air). 
     As is clear from the embodiments, in the compressor of the exemplary embodiment of the present invention, a common muffler chamber is provided between the suction port of each compression chamber and the compressor external suction piping system, and the suction passage from each suction port to the muffler chamber is set nearly at the same length. In this constitution, when part of the air sucked into each compression chamber flows back temporarily into each suction port, pulsations are generated in the suction passage in the same magnitude at a phase difference of 180 degrees. Accordingly, the suction efficiency of each compression chamber and each compression torque fluctuation due to effects of pulsation occur symmetrically. Therefore, the torque fluctuations during one revolution of the drive shaft can be dispersed, and the motor efficiency is enhanced, while the vibration of the compressor piping system can be reduced. 
     Pulsation of air propagating to the muffler chamber through the suction passage is attenuated in the muffler chamber. That is, the air flowing back from the suction passage is sucked into other suction passage through the muffler chamber, and the air pulsation is attenuated. As a result, since pulsation of suction air is not propagated to the compressor external suction piping system, vibration of the compressor external suction piping system can be decreased. 
     Besides, extreme oversupply of suction air does not occur, and excessive compression load is prevented. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, each suction passage from each suction port to the muffler chamber is disposed so that the fluid flow direction may not changeseverely. In this constitution, the passage resistance is extremely small when part of the air sucked into the compression chamber flows back into the muffler chamber through each suction port. Therefore, elevation of pressure of the gas remaining in the compression chamber is extremely small. As a result, lowering of compression efficiency can be suppressed. 
     In a compressor in accordance with a futher exemplary embodiment of the present invention, a drive shaft is supported by being disposed at a position on an opposite side of the motor, a muffler chamber is disposed at a subsidiary bearing side adjacent to the cylinder block, and a discharge port and a discharge valve are disposed at a main bearing side disposed at the motor side, while supporting the drive shaft together with the subsidiary bearing. In this constitution, if the muffler chamber is disposed, the distance between the main bearing and subsidiary bearing is short, and deformation of drive shaft can be decreased. Hence, vibration of the compressor and wear of the bearing due to imbalance of the rotary driving system can be decreased. 
     Since the muffler chamber in a space necessary for absorption of pulsation can be installed in a desired form, the pulsation attenuation effect can be increased. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, each suction passage is disposed by penetrating the subsidiary bearing in the axial direction. In this constitution, the suction passage to the muffler chamber is short, and hence the magnitude of pulsation decreases. As a result, vibration of the compressor external suction piping system is decreased, and the compressor suction efficiency can be enhanced. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, each suction hole opening in each compression chamber is formed by disposing a notch in the cylinder wall, at the end of the cylinder block at the side adjacent to the subsidiary bearing, and this notch is connected to the suction passage. In this constitution, when part of the air sucked into the compression chamber is returned to the muffler chamber through the suction port, the flow direction of the air is not changed so much. Hence, exhaust from the compression chamber to the muffler chamber is easy. As a result, elevation of pressure of suction air in the compression chamber before start of compression stroke is small, and lowering of compression efficiency can be suppressed. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the end of suction passage is formed opposite to both the notch and the compression chamber. In this constitution, when part of the air sucked into the compression chamber is returned to the muffler chamber through the suction port, exhaust from the compression chamber to the muffler chamber is further easier. As a result, elevation of pressure of suction air into the compression chamber before start of compression stroke hardly occurs, and lowering of compression efficiency can be prevented. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the muffler chamber is formed by disposing a partition member between the end wall of the enclosed container and the subsidiary bearing. In this constitution, each suction passage is shortest, pulsation occurring in each suction passage is suppressed, troubles due to pulsation is avoided, so that enhancement of compressor efficiency and decrease of vibration can be realized. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the muffler chamber is disposed outside of the end wall of the enclosed container at the subsidiary bearing side, and the suction passage is formed by penetrating through the end wall of the enclosed container. In this constitution, the suction passage is shortened, heating of the muffler chamber is prevented, and compression efficiency is enhanced. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the muffler chamber is disposed outside of the end wall of the enclosed container at the subsidiary bearing side, and the suction passage is formed by penetrating through the subsidiary bearing and the end wall of the enclosed container. In this constitution, the suction passage is further shortened, pulsation occurring in the suction port route is decreased, heating of suction air is prevented, and the compression efficiency is further enhanced. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, mainly the muffler chamber is held in the enclosed container by the communicating pipe for composing the suction passage. In this constitution, the muffler chamber can be easily disposed in the enclosed container, and the compressor can be lowered in cost. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the opening position of each suction passage into the muffler chamber is disposed almost symmetrically about the muffler chamber in the center. In this constitution, the pulsation attenuation action in the muffler chamber can be increased, and vibration of suction piping system can be decreased. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the utmost downstream end of the suction pipe connected to the external suction piping system of the compressor is extended up to the center of the muffler chamber, and the utmost downstream end is disposed higher than the opening end of each suction passage into the muffler chamber. In this constitution, the gas-liquid mixed fluid flowing into the muffler chamber from the external suction piping system of the compressor is prevented from flowing directly into each compression chamber, and the compressor durability is enhanced while avoiding liquid compression. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the utmost downstream end of the suction pipe connected to the compressor external suction piping system is disposed nearly in the common center to each opening of each suction passage to the muffler chamber. In this constitution, the pulsation attenuation action in the muffler chamber can be extremely increased, and the compression efficiency is enhanced and the vibration of suction piping system can be decreased. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the utmost downstream end of the suction pipe connected to the external suction piping system of the compressor is extended nearly up to the center of the muffler chamber, and means for changing the flow direction of the suction fluid by 90 degrees or more is disposed until the suction fluid flows into each suction passage from the opening at the utmost downstream end of the suction pipe. In this constitution, the gas-liquid mixed fluid flowing into the muffler chamber through the suction pipe is prevented from flowing directly into the compression chamber. As a result, the fluid in the liquid state heavier in specific gravity is separated from the gas by its inertial force, and only the gas smaller in specific gravity is sucked into the compression chamber through the suction passage. Accordingly, liquid compression in the compression chamber is prevented, and the durability of the compressor is enhanced. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, the roller is double rollers composed of inside roller and outside roller, and the outer circumference of the inside roller is designed to slide on the inner circumference of the outside roller. In this constitution, the inside roller sliding on the outer circumference of the crank of the drive shaft slides on the inner circumference of the outside roller, and the outside roller receives a frictional resistance against the ends of plural blades to cause an extreme slipping against the inside roller, and hence rotates at a very slow speed. As a result, the outside roller makes a slight slipping motion against the ends of the plural blades, and hence the wear of the outer circumference of the outside roller and the leading end of the blade is extremely decreased, and the durability is enhanced outstandingly. 
     In a compressor in accordance with a further exemplary embodiment of the present invention, a thrusting force is set on each blade so that the outside roller may rotate. In this constitution, as the outside roller rotates, the lubricating oil adhered to the outer circumference of the outside roller is gradually sent into the leading end sliding parts of the blades, and is presented for lubrication of the leading end sliding parts of the blades. Accordingly, an oil film is formed between the outer circumference of the outside roller and the leading ends of the blades, so that the durability may be further enhanced.