Motor operated compressor

Abstract

An electric compressor includes a first scroll, a second scroll engaged with the first scroll and configured to form a compression chamber between portions of the second scroll and the first scroll during orbiting motion of the second scroll relative to the first scroll, and a frame fixed on an opposite side of the second scroll from the first scroll. A back-pressure space is formed between the frame and the second scroll, and pressure in the back-pressure space pushes the second scroll toward the first scroll. A back-pressure passage connects the compression chamber and the back-pressure space, and a valve member is disposed in the back-pressure passage and selectively blocks movement of a fluid from the back-pressure space to the compression chamber.

What is claimed is: 
     
         1 . An electric compressor comprising:
 a first scroll;   a second scroll engaged with the first scroll and supported relative to the first scroll such that an orbiting motion of the second scroll relative to the first scroll forms a compression chamber between the second scroll and the first scroll;   a frame fixed to a housing of the electric compressor and positioned on an opposite side of the second scroll from the first scroll with the second scroll interposed between the first scroll and the frame, the frame forming a back-pressure space between the frame and the second scroll, the second scroll being supported in a direction toward the first scroll by a pressure in the back-pressure space;   a back-pressure passage connecting the compression chamber and the back-pressure space; and   a valve member disposed in the back-pressure passage and selectively blocking movement of a fluid from the back-pressure space to the compression chamber.   
     
     
         2 . The electric compressor of  claim 1 , wherein
 the back-pressure passage includes a back-pressure hole, one end of the back-pressure hole being in fluid communication with the compression chamber and an opposite end of the back-pressure hole being in fluid communication with the back-pressure space, and a valve accommodation recess being in fluid communication with the back-pressure hole, the valve accommodation recess accommodating the valve member, and   the valve member being configured as a check valve slidably movable inside the valve accommodation recess according to a pressure difference between the compression chamber and the back-pressure space.   
     
     
         3 . The electric compressor of  claim 2 , wherein
 the valve member includes a valve portion configured to open the back-pressure passage at a first position of the valve member and close the back-pressure passage at a second position of the valve member.   
     
     
         4 . The electric compressor of  claim 3 , wherein
 the valve portion has a first side surface, a second side surface, and a circumferential surface connecting the first side surface and the second side surface, and a diameter of the first side surface is greater than an inner diameter of the back-pressure hole and a diameter of the second side surface is smaller than an inner diameter of the valve accommodation recess.   
     
     
         5 . The electric compressor of  claim 4 , further comprising:
 an opening and closing surface formed on the first side surface of the valve portion such that at least a portion thereof is flat and formed with a diameter greater than the inner diameter of the back-pressure hole to block the back-pressure hole at the second position of the valve member;   a support surface formed on the second side surface of the valve portion and formed to contact a side surface of the valve accommodation recess at the first position of the valve member; and   a communication recess formed to a predetermined depth on the support surface, opened to the circumferential surface of the valve portion, and at least partially overlapping the back-pressure hole facing the second side surface.   
     
     
         6 . The electric compressor of  claim 5 , wherein
 the valve member further comprises at least one guide portion configured to guide the valve portion from the first position to the second position, and   the at least one guide portion extends in a radial direction toward an inner circumferential surface of the valve accommodation recess from the circumferential surface of the valve portion.   
     
     
         7 . The electric compressor of  claim 6 , wherein
 the at least one guide portion includes two guide portions protruding in a radial direction from portions of the circumferential surface of the valve portion, and the communication recess is opened to the circumferential surface of the valve portion positioned between the two guide portions.   
     
     
         8 . The electric compressor of  claim 7 , wherein
 the communication recess has at least two end portions opened to the circumferential surface of the valve portion.   
     
     
         9 . The electric compressor of  claim 6 , wherein
 the at least one guide portion includes a plurality of guide portions, and respective guide portions of the plurality of guide portions are formed at equal intervals along a circumferential direction of the circumferential surface of the valve portion.   
     
     
         10 . The electric compressor of  claim 6 , wherein
 the at least one guide portion is a single guide portion, and a subtended angle of the single guide portion is greater than or equal to approximately 180°.   
     
     
         11 . The electric compressor of  claim 6 , wherein
 the at least one guide portion has a thickness approximately equal to or smaller than a thickness of the valve portion.   
     
     
         12 . The electric compressor of  claim 6 , wherein
 at least one guide recess is formed on an inner circumferential surface of the valve accommodation recess and a respective one of the at least one guide portion is inserted into the at least one guide recess and restrained by the at least one guide recess from movement in a circumferential direction.   
     
     
         13 . The electric compressor of  claim 1 , wherein
 an elastic member is disposed on any one of opposite sides of the valve member in a direction of movement of the valve member.   
     
     
         14 . The electric compressor of  claim 1 , wherein
 the back-pressure passage includes:   a first back-pressure hole formed in the first scroll and in fluid communication with the compression chamber; and   a second back-pressure hole formed in the frame and in fluid communication with the back-pressure hole,   wherein the first back-pressure hole and the second back-pressure hole are in fluid communication with each other; and   a valve accommodation recess accommodating the valve member is formed at least in part in at least one of the first scroll or the frame.   
     
     
         15 . The electric compressor of  claim 1 , wherein
 the back-pressure passage is formed penetrating through the second scroll and in fluid communication with the back-pressure space,   a valve accommodation recess is formed in a middle portion of the back-pressure passage,   a stopper member configured for limiting movement of the valve member is inserted in and coupled to the valve accommodation recess, and   the stopper member includes a back-pressure hole in fluid communication with the back-pressure passage.   
     
     
         16 . An electric compressor comprising:
 a frame;   a first scroll fixedly supported in the frame;   
       a second scroll pivotably supported relative to the frame and the first scroll and engaged with the first scroll;
 a compression chamber formed between the first scroll and the second scroll and configured to decrease in volume from an outer portion of the compression chamber toward an inner portion of the compression chamber upon relative movement between the first scroll and the second scroll to compress a fluid contained within the compression chamber; 
 a back-pressure space formed between the second scroll and the frame, wherein pressure within the back-pressure space acts on the second scroll and supports the second scroll toward the first scroll; 
 a back-pressure flow path connecting the compression chamber and the back-pressure space; 
 a valve accommodation recess formed in a middle portion of the back-pressure flow path; and 
 a check valve disposed in the valve accommodation recess and configured to block the back-pressure flow path when a pressure in the back-pressure space is higher than a pressure in the compression chamber. 
 
     
     
         17 . The electric compressor of  claim 16 , wherein
 the check valve includes a valve portion, the valve portion formed to include a diameter greater than an inner diameter of the back-pressure flow path and smaller than an inner diameter of the valve accommodation recess,   at least a portion of one side surface of the valve portion is formed substantially flat to selectively establish close contact with one side of the valve accommodation recess and block the back-pressure flow path in a first position of the valve portion, and   the other side surface of the valve portion includes a communication recess configured to open the back-pressure flow path when the other side surface of the valve portion establishes close contact with the other side of the valve accommodation recess in a second position of the valve portion.   
     
     
         18 . The electric compressor of  claim 17 , wherein
 the check valve further includes at least one guide portion in slidable contact with an inner circumferential surface of the valve accommodation recess, and   the at least one guide portion protrudes from a circumferential surface of the valve portion along a circumferential direction of the valve portion.   
     
     
         19 . An electric compressor comprising:
 a frame;   a fixed scroll supported in the frame;   an orbiting scroll pivotably supported relative to the frame and the fixed scroll, engaged with the fixed scroll, and interposed between the fixed scroll and the frame;   a compression chamber including at least two variable volumes formed between the fixed scroll and the orbiting scroll, wherein orbital movement of the orbiting scroll relative to the fixed scroll causes the variable volumes of the compression chamber to alternately increase in volume to draw fluid into the compression chamber and decrease in volume to compress the fluid contained within the compression chamber and discharge the fluid;   a back-pressure space formed between the orbiting scroll and the frame, wherein pressure of fluid within the back-pressure space acts on a first side of the orbiting scroll opposite from a second side of the orbiting scroll engaged with the fixed scroll, the pressure pushing the orbiting scroll in a direction toward the fixed scroll;   a back-pressure passage connecting the compression chamber and the back-pressure space;   a valve accommodation recess formed in a portion of the back-pressure passage; and   a check valve disposed in the valve accommodation recess and configured to move to a position in which the check valve blocks the back-pressure passage when a pressure in the back-pressure space is higher than a pressure in the compression chamber.   
     
     
         20 . The electric compressor of  claim 19 , wherein:
 the back-pressure passage is formed as one of a combination of through holes formed in the fixed scroll and the frame, or a single through hole formed in the orbiting scroll.