Rotary compressor

Abstract

A rotary compressor is disclosed. A back pressure pocket among a plurality of back pressure pockets closest to a discharge port disposed in at least one of main bearing or sub bearing is radially spaced from an inner circumferential surface of a bearing hole, and communicates with an inner space of a casing through a back pressure passage formed through at least one of the main bearing or the sub bearing. Accordingly, the back pressure pocket closest to the discharge port may strongly support a vane passing near a reference point toward a cylinder while forming a discharge pressure, or a super discharge pressure higher than the discharge pressure. This may suppress or prevent chattering of the vane near the reference point to reduce vibration noise while suppressing or preventing wear between the vane and the cylinder to enhance compression efficiency. This may also suppress or prevent leakage between compression chambers, thereby preventing delay of initial startup of the compressor.

What is claimed is: 
     
         1 . A rotary compressor, comprising:
 a drive motor disposed in an inner space of a casing;   a rotational shaft coupled to a rotor of the drive motor;   a cylinder disposed in the inner space of the casing to define a compression space;   a roller disposed on the rotational shaft and accommodated in the compression space, to be eccentric with respect to an inner circumferential surface of the cylinder;   a plurality of vanes slidably inserted, respectively, into a plurality of vane slots provided in the roller; and   a main bearing and a sub bearing, respectively, disposed on both sides of the cylinder in an axial direction to define the compression space together with the cylinder, wherein at least one of the main bearing or the sub bearing includes at least one discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, wherein a plurality of back pressure pockets that communicates with rear sides of the plurality of vanes is disposed at one side of the at least one discharge port spaced apart from each other in a circumferential direction, and wherein a first back pressure pocket, which is closest to the at least one discharge port of the plurality of back pressure pockets, communicates with the inner space of the casing via a back pressure passage that penetrates through at least one of the main bearing or the sub bearing.   
     
     
         2 . The rotary compressor of  claim 1 , wherein each of the main bearing and the sub bearing includes a bearing hole into which the rotational shaft is inserted and supported, and wherein the first back pressure pocket is radially spaced apart from an inner circumferential surface of the bearing hole so as to be isolated from the bearing hole. 
     
     
         3 . The rotary compressor of  claim 1 , wherein the rotational shaft includes an oil supply passage formed therein, and at least one oil supply hole that extends from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft, and wherein the back pressure passage has an inner diameter smaller than or equal to an inner diameter of the oil supply hole. 
     
     
         4 . The rotary compressor of  claim 1 , wherein the rotational shaft includes an oil supply passage formed therein, and at least one oil supply hole that extends from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft, and wherein the back pressure passage is located at one side of the oil supply hole in the axial direction. 
     
     
         5 . The rotary compressor of  claim 1 , wherein the back pressure passage is eccentric from a center of the first back pressure pocket to a reference point at which the roller and the cylinder are closest to each other. 
     
     
         6 . The rotary compressor of  claim 1 , wherein the back pressure passage portion is located at a position at which it periodically overlaps a vane of the plurality of vanes during a reciprocating motion of the vane. 
     
     
         7 . The rotary compressor of  claim 6 , wherein the back pressure passage has an inner diameter smaller than a width of the vane. 
     
     
         8 . The rotary compressor of  claim 1 , wherein the rotational shaft includes an oil supply passage formed therein, and wherein the back pressure passage comprises:
 a first back pressure hole formed in a penetrating manner from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft; and   a second back pressure hole formed through at least one of the main bearing or the sub bearing to communicate with the first back pressure hole and the back pressure pocket.   
     
     
         9 . The rotary compressor of  claim 8 , wherein the second back pressure hole has an inner diameter smaller than or equal to an inner diameter of the first back pressure hole. 
     
     
         10 . The rotary compressor of  claim 8 , wherein a communication groove is formed between the first back pressure hole and the second back pressure hole, and wherein the communication groove has a cross-sectional area larger than at least one of a cross-sectional area of the first back pressure hole or a cross-sectional area of the second back pressure hole. 
     
     
         11 . The rotary compressor of  claim 10 , wherein the communication groove is formed in an arcuate shape so that the first back pressure hole and the second back pressure hole communicate with each other periodically, or the communication groove is formed in a circular shape so that the first back pressure hole and the second back pressure hole communicate with each other continuously. 
     
     
         12 . The rotary compressor of  claim 1 , wherein a first end of the back pressure passage communicates with the first back pressure pocket and a second end of the back pressure passage communicates with the inner space of the casing through at least one of the main bearing or the sub bearing. 
     
     
         13 . The rotary compressor of  claim 1 , wherein the first back pressure pocket has a volume smaller than a volume of a second back pressure pocket of the plurality of back pressure pockets. 
     
     
         14 . The rotary compressor of  claim 13 , wherein the first back pressure pocket has an arcuate length shorter than an arcuate length of the second back pressure pocket, or the first back pressure pocket has a depth smaller than a depth of the second back pressure pocket. 
     
     
         15 . The rotary compressor of  claim 1 , wherein a lubrication portion is formed at at least one of the main bearing or the sub bearing radially outside of the first back pressure pocket, and wherein at least a portion of the lubrication portion radially overlaps the first back pressure pocket. 
     
     
         16 . The rotary compressor of  claim 15 , wherein the lubrication portion comprises:
 at least one lubrication pocket spaced apart from the first back pressure pocket; and   at least one lubrication passage that connects the at least one lubrication pocket and the inner space of the casing to guide oil stored in the inner space of the casing to the at least one lubrication pocket, wherein the at least one lubrication pocket is configured as a groove that extends in the circumferential direction, and wherein the at least one lubrication passage comprises one or more lubrication passage in the circumferential direction of the at least one lubrication pocket.   
     
     
         17 . The rotary compressor of  claim 15 , wherein the lubrication portion comprises:
 at least one lubrication pocket spaced apart from the first back pressure pocket; and   at least one lubrication passage that connects the at least one lubrication pocket and the inner space of the casing to guide oil stored in the inner space of the casing to the at least one lubrication pocket, wherein the at least one lubrication pocket comprises a plurality of lubrication pockets spaced apart from each other in the circumferential direction, and wherein the at least one lubrication passage independently communicates with each of the plurality of lubrication pockets.   
     
     
         18 . The rotary compressor of  claim 15 , wherein the lubrication portion comprises at least one lubrication passage formed through the sub bearing, and wherein a first end of the at least one lubrication passage is open toward a vane of the plurality of vanes at a first axial side surface of the sub bearing, and a second end is open toward the inner space of the casing at a second axial side surface of the sub bearing. 
     
     
         19 . The rotary compressor of  claim 15 , wherein the lubrication portion comprises:
 at least one lubrication pocket spaced apart from the first back pressure pocket; and   at least one lubrication passage that extends from at least one of the plurality of back pressure pockets, excluding the first back pressure pocket, to communicate with the at least one lubrication pocket.   
     
     
         20 . The rotary compressor of  claim 19 , wherein an axial depth of the at least one lubrication pocket is smaller than or equal to an axial depth of the back pressure pocket to which the at least one lubrication pocket is connected. 
     
     
         21 . A rotary compressor, comprising:
 a drive motor disposed in an inner space of a casing;   a rotational shaft coupled to a rotor of the drive motor;   a cylinder disposed in the inner space of the casing to define a compression space;   a roller disposed on the rotational shaft and accommodated in the compression space, to be eccentric with respect to an inner circumferential surface of the cylinder;   a plurality of vanes slidably inserted, respectively, into a plurality of vane slots provided in the roller; and   a main bearing and a sub bearing, respectively, disposed on both sides of the cylinder in an axial direction to define the compression space together with the cylinder, wherein at least one of the main bearing or the sub bearing includes at least one discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, wherein a plurality of back pressure pockets that communicates with rear sides of the plurality of vanes is disposed at one side of the at least one discharge port spaced apart from each other in a circumferential direction, wherein a first back pressure pocket, which is closest to the at least one discharge port of the plurality of back pressure pockets, communicates with the inner space of the casing via a back pressure passage that penetrates through at least one of the main bearing or the sub bearing and the rotational shaft, and wherein the back pressure passage is eccentric from a center of the first back pressure pocket to a reference point at which the roller and the cylinder are closest to each other.   
     
     
         22 . A rotary compressor, comprising:
 a drive motor disposed in an inner space of a casing;   a rotational shaft coupled to a rotor of the drive motor;   a cylinder disposed in the inner space of the casing to define a compression space;   a roller disposed on the rotational shaft and accommodated in the compression space, to be eccentric with respect to an inner circumferential surface of the cylinder;   a plurality of vanes slidably inserted, respectively, into a plurality of vane slots provided in the roller; and   a main bearing and a sub bearing, respectively, disposed on both sides of the cylinder in an axial direction to define the compression space together with the cylinder, wherein at least one of the main bearing or the sub bearing includes at least one discharge port through which refrigerant compressed in the compression space is discharged to the inner space of the casing, wherein a plurality of back pressure pockets that communicates with rear sides of the plurality of vanes is disposed at one side of the at least one discharge port spaced apart from each other in a circumferential direction, wherein a first back pressure pocket, which is closest to the at least one discharge port of the plurality of back pressure pockets, communicates with the inner space of the casing via a back pressure passage that penetrates through at least one of the main bearing or the sub bearing, wherein the rotational shaft includes an oil supply passage formed therein, and wherein the back pressure passage comprises:
 a first back pressure hole that extends from an inner circumferential surface of the oil supply passage to an outer circumferential surface of the rotational shaft; 
 a second back pressure hole formed through at least one of the main bearing or the sub bearing to communicate with the first back pressure hole and the first back pressure pocket; and 
 a communication groove formed between the first back pressure hole and the second back pressure hole.