Lubrication of a rotary compressor

FIG. 1 is a vertical cross-sectional view illustrating an example of a rotary compressor according to the present invention. FIG. 2 is a horizontal cross-sectional view of first and second compressing units according to the example when viewed from above.

As illustrated in FIG. 1 , a rotary compressor 1 of the example includes a compressing unit 12 that is disposed in the lower section of a vertically-positioned airtight compressor housing 10 which has a cylindrical shape and a motor 11 that is disposed in the upper section of the compressor housing 10 and drives the compressing unit 12 via a rotation shaft 15 .

A stator 111 of the motor 11 is formed in a cylindrical shape and is shrink-fitted and fixed in the inner circumferential surface of the compressor housing 10 . A rotor 112 of the motor 11 is disposed inside the cylindrical stator 111 and is shrink-fitted and fixed to the rotation shaft 15 that mechanically connects the motor 11 with the compressing unit 12 .

The compressing unit 12 includes a first compressing section 12 S and a second compressing section 12 T that is disposed in parallel with the first compressing section 12 S and is stacked on the first compressing section 12 S. As illustrated in FIG. 2 , the first and second compressing units 12 S and 12 T include annular first and second cylinders 121 S and 121 T in which first and second inlet holes 135 S and 135 T that are radially disposed and first and second vane grooves 128 S and 128 T are provided in first and second side-flared portions 122 S and 122 T.

As illustrated in FIG. 2 , circular first and second cylinder inner walls 123 S and 123 T are formed in the first and second cylinders 121 S and 121 T so as to be concentric with the rotation shaft 15 of the motor 11 . First and second annular pistons 125 S and 125 T which have an outer diameter smaller than an inner diameter of the cylinder are provided inside the first and second cylinder inner walls 123 S and 123 T, respectively. First and second operation chambers 130 S and 130 T which suck in, compress, and discharge a refrigerant gas are formed between the first and second cylinder inner walls 123 S and 123 T and the first and second annular pistons 125 S and 125 T.

The first and second vane grooves 128 S and 128 T are formed over the entire cylinder height of the first and second cylinders 121 S and 121 T in a radial direction from the first and second cylinder inner walls 123 S and 123 T. First and second vanes 127 S and 127 T, each of which has a plate shape, are slidably fit in the first and second vane grooves 128 S and 128 T.

As illustrated in FIG. 2 , first and second spring bores 124 S and 124 T are formed in a deep portion of the first and second vane grooves 128 S and 128 T such that communication from the outer circumferential portions of the first and second cylinders 121 S and 121 T to the first and second vane grooves 128 S and 128 T is performed. First and second vane springs (not illustrated) which press the back surface of the first and second vanes 127 S and 127 T are inserted into the first and second spring bores 124 S and 124 T.

When the rotary compressor 1 is started, the first and second vanes 127 S and 127 T protrude from the inside of the first and second vane grooves 128 S and 128 T to the inside of the first and second operation chambers 130 S and 130 T due to bounces of the first and second vane springs and ends of the vanes come into contact with the outer circumferential surfaces of the first and second annular pistons 125 S and 125 T. Then, the first and second vanes 127 S and 127 T partition the first and second operation chambers 130 S and 130 T into first and second inlet chambers 131 S and 131 T and first and second compression chambers 133 S and 133 T.

In addition, the refrigerant gas compressed in the compressor housing 10 is guided into the first and second cylinders 121 S and 121 T by communicating the deep portion of the first and second vane grooves 128 S and 128 T with the inside of the compressor housing 10 via an opening R illustrated in FIG. 1 . First and second pressure guiding-in paths 129 S and 129 T which cause back pressures to be applied by the pressure of the refrigerant gas are formed in the first and second vanes 127 S and 127 T.

The first and second inlet holes 135 S and 135 T which cause the first and second inlet chambers 131 S and 131 T to communicate with the outside are provided in the first and second cylinders 121 S and 121 T such that a refrigerant is sucked into the first and second inlet chambers 131 S and 131 T from the outside.

In addition, as illustrated in FIG. 1 , an intermediate partition plate 140 is disposed between the first cylinder 121 S and the second cylinder 121 T and partitions and closes the first operation chamber 130 S (refer to FIG. 2 ) of the first cylinder 121 S from the second operation chamber 130 T (refer to FIG. 2 ) of the second cylinder 121 T. A lower end plate 160 S is disposed on a lower end portion of the first cylinder 121 S and closes the first operation chamber 130 S of the first cylinder 121 S. In addition, an upper end plate 160 T is disposed on an upper end portion of the second cylinder 121 T and closes the second operation chamber 130 T of the second cylinder 121 T.

A sub-bearing unit 161 S is formed on the lower end plate 160 S and a sub-shaft unit 151 of the rotation shaft 15 is rotatably supported in the sub-bearing unit 161 S. A main-bearing unit 161 T is formed on the upper end plate 160 T and a main-shaft unit 153 of the rotation shaft 15 is rotatably supported in the main-bearing unit 161 T.

The rotation shaft 15 includes a first eccentric portion 152 S and a second eccentric portion 152 T which are eccentric by a 180° phase shift from each other. The first eccentric portion 152 S is rotatably fit in the first annular piston 125 S of the first compressing unit 12 S. The second eccentric portion 152 T is rotatably fit in the second annular piston 125 T of the second compressing unit 12 T.

When the rotation shaft 15 rotates, the first and second annular pistons 125 S and 125 T make orbital motions inside the first and second cylinders 121 S and 121 T along the first and second cylinder inner walls 123 S and 123 T in a counterclockwise direction in FIG. 2 . Accordingly, the first and second vanes 127 S and 127 T perform reciprocal motions. The motions of the first and second annular pistons 125 S and 125 T and the first and second vanes 127 S and 127 T cause volumes of the first and second inlet chambers 131 S and 131 T and the first and second compression chambers 133 S and 133 T to be continually changed. In this manner, the compressing unit 12 continually sucks in, compresses, and discharges the refrigerant gas.

As illustrated in FIG. 1 , a lower muffler cover 170 S is disposed on the lower side of the lower end plate 160 S and a lower muffler chamber 180 S is formed between the lower endplate 160 S and the lower muffler cover 170 S. The first compressing unit 12 S opens to the lower muffler chamber 180 S. That is, a first outlet 190 S (refer to FIG. 2 ) through which the first compression chamber 133 S of the first cylinder 121 S communicates with the lower muffler chamber 180 S is provided in the vicinity of the first vane 127 S of the lower end plate 160 S. In addition, a first discharge valve 200 S which prevents the compressed refrigerant gas from flowing backward is disposed in the first outlet 190 S.

The lower muffler chamber 180 S is a single annular chamber. The lower muffler chamber 180 S is a part of a communication path through which a discharge side of the first compressing unit 12 S communicates with the inside of the upper muffler chamber 180 T bypassing through a refrigerant path 136 (refer to FIG. 2 ) which penetrates the lower end plate 160 S, the first cylinder 121 S, the intermediate partition plate 140 , the second cylinder 121 T and the upper end plate 160 T. Further, the lower muffler chamber 180 S causes pressure pulsation of the discharged refrigerant gas to be reduced. In addition, a first discharge valve cover 201 S which controls an amount of flexural valve opening of the first discharge valve 200 S is stacked on the first discharge valve 200 S and is fixed to the first discharge valve 200 S using a rivet. The first outlet 190 S, the first discharge valve 200 S, and the first discharge valve cover 201 S configure a first discharge valve unit of the lower end plate 160 S.

As illustrated in FIG. 1 , an upper muffler cover 170 T is disposed on the upper side of the upper end plate 160 T and an upper muffler chamber 180 T is formed between the upper end plate 160 T and the upper muffler cover 170 T. A second outlet 190 T (refer to FIG. 2 ) through which the second compression chamber 133 T of the second cylinder 121 T communicates with the upper muffler chamber 180 T is provided in the vicinity of the second vane 127 T of the upper end plate 160 T. A reed valve type second discharge valve 200 T which prevents the compressed refrigerant gas from flowing backward is disposed in the second outlet 190 T. In addition, a second discharge valve cover 201 T which controls an amount of flexural valve opening of the second discharge valve 200 T is stacked on the second discharge valve 200 T and is fixed using a rivet with the second discharge valve 200 T. The upper muffler chamber 180 T causes pressure pulsation of discharged refrigerant to be reduced. The second outlet 190 T, the second discharge valve 200 T, and the second discharge valve cover 201 T configure a second discharge valve unit of the upper end plate 160 T.

The first cylinder 121 S, the lower end plate 160 S, the lower muffler cover 170 S, the second cylinder 121 T, the upper end plate 160 T, the upper muffler cover 170 T, and the intermediate partition plate 140 are integrally fastened using a plurality of penetrating bolts 175 or the like. The outer circumferential portion of the upper end plate 160 T of the compressing unit 12 which is integrally fastened using the penetrating bolts 175 or the like is firmly fixed to the compressor housing 10 through spot welding such that the compressing unit 12 is fixed to the compressor housing 10 .

First and second through holes 101 and 102 are provided in the outer-side wall of the cylindrical compressor housing 10 at an interval in an axial direction in this order from a lower section thereof so as to communicate with first and second inlet pipes 104 and 105 , respectively. In addition, outside the compressor housing 10 , an accumulator 25 which is formed of a separate airtight cylindrical container is held by an accumulator holder 252 and an accumulator band 253 .

A system connecting pipe 255 which is connected to an evaporator in a refrigeration cycle is connected at the center of the top portion of the accumulator 25 . First and second low-pressure communication tubes 31 S and 31 T, each of which has one end extending toward the upward side inside the accumulator 25 , and which have the other ends connected to the other end of each of the first and second inlet pipes 104 and 105 , are connected to a bottom through hole 257 provided in the bottom of the accumulator 25 .

The first and second low-pressure communication tubes 31 S and 31 T which guide a low pressure refrigerant in the refrigeration cycle to the first and second compressing units 12 S and 12 T via the accumulator 25 are connected to the first and second inlet holes 135 S and 135 T (refer to FIG. 2 ) of the first and second cylinders 121 S and 121 T via the first and second inlet pipes 104 and 105 as an inlet unit. That is, the first and second inlet holes 135 S and 135 T are connected to the evaporator of the refrigeration cycle in parallel.

A discharge pipe 107 as a discharge unit which is connected to the refrigeration cycle and discharges a high pressure refrigerant gas to a side of a condenser in the refrigeration cycle is connected to the top portion of the compressor housing 10 . That is, the first and second outlets 190 S and 190 T are connected to the condenser in the refrigeration cycle.

Lubricant oil is sealed in the compressor housing 10 substantially to the elevation of the second cylinder 121 T. In addition, the lubricant oil is sucked up from a lubricating pipe 16 attached to the lower end portion of the rotation shaft 15 , using a pump blade 157 (refer to FIG. 5 ) to be described below which is inserted into the lower section of the rotation shaft 15 . The lubricant oil circulates through the compressing unit 12 , lubricates sliding components, and seals a fine gap in the compressing unit 12 .

Next, a lubricating mechanism of Example 1 which is a characteristic configuration of the rotary compressor of the example will be described with reference to FIG. 3 to FIG. 8 . FIG. 3 is a side view of a lower section of a rotation shaft of Example 1. FIG. 4 is a vertical cross-sectional view of a lubricating pipe of Example 1. FIG. 5 is a side view of a pump blade of Example 1. FIG. 6-1 is a cross-sectional view from below taken along line A-A in FIG. 3 . FIG. 6-2 is a cross-sectional view from below taken along line B-B in FIG. 3 . FIG. 7 is a view from below along arrow C in FIG. 3 and a view illustrating an acting state of a refrigerant compressive load on a rotation shaft when a rotation angle of an eccentric portion of the rotation shaft becomes 270°. FIG. 8 is a view illustrating a relationship between the rotation angle of the eccentric portion of the rotation shaft and a refrigerant compressive load.

As illustrated in FIG. 3 , FIG. 6-1 , and FIG. 6-2 , a vertical fitting hole 155 b, vertical lubricating holes 155 and 155 a, in this order from the lower section, and first and second horizontal lubricating holes 156 a and 156 b which supply the lubricant oil to the compressing unit 12 (refer to FIG. 1 ) from the vertical lubricating hole 155 are provided in the rotation shaft 15 . The vertical fitting hole 155 b is formed to have an inner diameter greater than the inner diameter of the vertical lubricating hole 155 .

As illustrated in FIG. 4 , the lubricating pipe 16 is manufactured using a soft material such as copper or aluminum, has an inlet 16 a on the lower end thereof, and is opened at the upper end thereof. As illustrated in FIG. 5 , the pump blade 157 is made of a metal plate and has a blade portion 157 a and a base portion 157 b that is formed to be wider than the blade portion 157 a. The blade portion 157 a is subjected to a twisting process and has a 180°-twisted shape.

When the lubricating pipe 16 and the pump blade 157 are assembled into the rotation shaft 15 , first, the base portion 157 b of the pump blade 157 is pressed against and fixed to the lower section inside the lubricating pipe 16 . A horizontal width H 1 of the base portion 157 b has a size relationship (H 1 >φD 1 ) of an interference fit with the inner diameter φD 1 of the lubricating pipe 16 and the pump blade 157 is fixed to the lubricating pipe 16 .

Next, the blade portion 157 a of the pump blade 157 is inserted into the vertical lubricating hole 155 of the rotation shaft 15 and the upper portion of the lubricating pipe 16 is pressed into the vertical fitting hole 155 b and the fit lubricating pipe 16 is fixed to the rotation shaft 15 . The length of the lubricating pipe 16 is substantially twice the depth of the vertical fitting hole 155 b of the rotation shaft 15 . The lower section of the lubricating pipe 16 protrudes toward the downward side from the vertical fitting hole 155 b.

As illustrated in FIG. 3 , FIG. 6-1 , and FIG. 7 , the first horizontal lubricating holes 156 a of a lubricating mechanism 159 A of Example 1 are formed on a side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 . In addition, the first horizontal lubricating holes 156 a are formed as a horizontal through hole of the rotation shaft 15 in a 40° phase shifted direction from an eccentric direction (downward side in FIG. 3 and FIG. 6-1 and left side in FIG. 7 ) of the first eccentric portion 152 S in a direction opposite to the rotating direction (clockwise direction in FIG. 6-1 and FIG. 7 because the views are seen from below) of the rotation shaft 15 .

As illustrated in FIG. 3 and FIG. 6-2 , the second horizontal lubricating holes 156 b of the lubricating mechanism 159 A of Example 1 are formed on a side of the main-shaft unit 153 of the second eccentric portion 152 T of the rotation shaft 15 . In addition, the second horizontal lubricating holes 156 b are formed as a horizontal through hole of the rotation shaft 15 in a 40° phase shifted direction from an eccentric direction (upward side in FIG. 3 and FIG. 6-2 ) of the second eccentric portion 152 T in a direction opposite to the rotating direction (clockwise direction in FIG. 6-2 because the view is seen from below) of the rotation shaft 15 .

Horizontal lubricating holes in the related art are formed in directions orthogonal to the eccentric directions of the first and second eccentric portions 152 S and 152 T because the rotation shaft 15 is easily fixed during a hole-drilling process. A hole-drilling process of the first and second horizontal lubricating holes 156 a and 156 b of Example 1 may be performed by inclining the first and second eccentric portions 152 S and 152 T with respect to a horizontal plane using a dedicated tool.

As illustrated in FIG. 8 , according to calculation in a case where R410A is used as an example of the refrigerant, under a high compression rate (heavy load) condition during a heating operation or the like of the rotary compressor 1 , the first and second eccentric portions 152 S and 152 T receive the maximum load due to a compression reaction force of the refrigerant at the time of rotation of about 270° from the dead center (when the eccentric direction is the same as a direction of the positions of the first and second vanes 127 S and 127 T) in the clockwise direction when viewed from below.

At this time, as illustrated in FIG. 7 , the maximum load is applied in a 50° phase shifted direction from the eccentric direction (left direction in FIG. 7 ) of the first eccentric portion 152 S in the clockwise direction. In addition, the first horizontal lubricating holes 156 a formed in a 40° phase shifted direction in the counterclockwise direction from the eccentric direction (left direction in FIG. 7 ) of the first eccentric portion 152 S are positioned in a direction of a neutral axis in which no stress is generated due to bending moment that acts on the rotation shaft 15 . Hence, high tensile or compressive stress is not generated around the first horizontal lubricating hole 156 a around which strength is low. Therefore, the strength of the rotation shaft 15 does not become insufficient due to the first horizontal lubricating hole 156 a.

FIG. 9 is a view illustrating an acting state of a refrigerant compressive load on a rotation shaft of a rotary compressor in the related art which is disclosed in PTL 1 when a rotation angle of an eccentric portion of the rotation shaft becomes 270°. As illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, a first horizontal lubricating hole 956 a is positioned in a 40° phase shifted direction from the neutral axis in the clockwise direction. In addition, a first horizontal lubricating hole 956 b is positioned in a 50° phase shifted direction from the neutral axis in the counterclockwise direction. Therefore, high compressive stress is generated around the first horizontal lubricating holes 956 a and 956 b in the related art. High tensile or compressive stress is not generated around the first horizontal lubricating hole 156 a of Example 1. Hence, an advantage is achieved in stress reduction, compared to the first horizontal lubricating holes 956 a and 956 b in the related art.

In addition, the first horizontal lubricating holes 156 a have openings that are spaced apart by 180° from each other on a circumferential surface of the rotation shaft 15 . Hence, the first horizontal lubricating holes 156 a have uniform lubricating intervals compared to the first horizontal lubricating holes 956 a and 956 b in the related art. Further, the first horizontal lubricating holes 156 a forma horizontal through hole and need the hole-drilling process only once and thus, a processing cost is reduced.

As above, the first horizontal lubricating hole 156 a of Example 1 is described. The second horizontal lubricating hole 156 b has the same acting effects as the first horizontal lubricating hole 156 a and thus, description thereof is omitted.

As described above, the lubricating mechanism 159 A of Example 1 which includes the lubricating pipe 16 , the pump blade 157 , the vertical lubricating holes 155 and 155 a, the first and second horizontal lubricating holes 156 a and 156 b, and the like sucks up the lubricant oil stored in the lower section of the compressor housing 10 from the lubricating pipe 16 . Accordingly, the sub-shaft unit 151 , the compressing unit 12 , the main-shaft unit 153 , and the like are lubricated.

FIG. 10 is a side view of a lower section of a rotation shaft of Example 2. FIG. 11-1 is a cross-sectional view from below taken along line D-D in FIG. 10 . FIG. 11-2 is a cross-sectional view from below taken along line E-E in FIG. 10 . FIG. 12 is a view from below along arrow F in FIG. 10 and a view illustrating an acting state of a refrigerant compressive load on the rotation shaft when a rotation angle of an eccentric portion of the rotation shaft becomes 180°. FIG. 13 is a view from below along arrow F in FIG. 10 and a view illustrating an acting state of a refrigerant compressive load on the rotation shaft when a rotation angle of the eccentric portion of the rotation shaft becomes 270°.

As illustrated in FIG. 10 , FIG. 11-1 , and FIG. 12 , first horizontal lubricating holes 156 c of a lubricating mechanism 159 B of Example 2 are formed on a side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 and are formed as a horizontal through hole of the rotation shaft 15 in the same direction as the eccentric direction (downward side in FIG. 10 , FIG. 11-1 , and FIG. 12 ) of the first eccentric portion 152 S.

As illustrated in FIG. 10 and FIG. 11-2 , second horizontal lubricating holes 156 d of the lubricating mechanism 159 B of Example 2 are formed on the side of the main-shaft unit 153 of the second eccentric portion 152 T of the rotation shaft 15 and are formed as a horizontal through hole of the rotation shaft 15 in the same direction as the eccentric direction (upward side in FIG. 10 , FIG. 11-2 , and FIG. 12 ) of the second eccentric portion 152 T.

As illustrated in FIG. 8 , according to calculation in a case where R410A is used as the refrigerant, under a rated cooling condition of the rotary compressor 1 , the first and second eccentric portions 152 S and 152 T receive the maximum load due to a compression reaction force of the refrigerant at the time of rotation of about 180° from the dead center (when the eccentric direction is the same as a direction of the positions of the first and second vanes 127 S and 127 T) in the clockwise direction when viewed from below.

At this time, as illustrated in FIG. 12 , the maximum load is applied in a perpendicular direction (left direction in FIG. 12 ) to the eccentric direction (downward direction in FIG. 12 ) of the first eccentric portion 152 S. In addition, the first horizontal lubricating holes 156 c formed in the same direction as the eccentric direction of the first eccentric portion 152 S are positioned in the direction of a neutral axis in which no stress is generated due to bending moment that acts on the rotation shaft 15 . Hence, concentrated tensile or compressive stress is not generated around the first horizontal lubricating hole 156 c around which strength is low.

In addition, as illustrated in FIG. 8 , under a high compression rate (heavy load) condition during a heating operation or the like of the rotary compressor 1 , the first and second eccentric portions 152 S and 152 T receive the maximum load due to a compression reaction force of the refrigerant at the time of rotation of about 270° from the dead center (when the eccentric direction is the same as a direction of the positions of the first and second vanes 127 S and 127 T) in the clockwise direction when viewed from below.

At this time, as illustrated in FIG. 13 , the maximum load is applied in a 50° phase shifted direction from the eccentric direction (left direction in FIG. 13 ) of the first eccentric portion 152 S in the clockwise direction. In addition, the first horizontal lubricating holes 156 c formed in the same direction as the eccentric direction of the first eccentric portion 152 S are positioned in a 40° phase shifted direction from the neutral axis in the clockwise direction.

As illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, the first horizontal lubricating hole 956 a is positioned in a 40° phase shifted direction from the neutral axis in the clockwise direction. In addition, a first horizontal lubricating hole 956 b is positioned in a 50° phase shifted direction from the neutral axis in the counterclockwise direction. Therefore, the same compressive stress is generated to one first horizontal lubricating hole 156 c of Example 2 as that to the first horizontal lubricating hole 956 a in the related art. However, tensile stress generated around the other first horizontal lubricating hole 156 c of Example 2 is less than the compressive stress generated around the first horizontal lubricating hole 956 b in the related art, and thus the first horizontal lubricating holes 156 c have advantages in stress reduction.

As above, the first horizontal lubricating hole 156 c is described. The second horizontal lubricating hole 156 d has the same acting effects as the first horizontal lubricating hole 156 c and thus, description thereof is omitted.

As described above, the lubricating mechanism 159 B of Example 2 which includes the lubricating pipe 16 , the pump blade 157 , the vertical lubricating holes 155 and 155 a, the first and second horizontal lubricating holes 156 c and 156 d, and the like sucks up the lubricant oil stored in the lower section of the compressor housing 10 from the lubricating pipe 16 . Accordingly, the sub-shaft unit 151 , the compressing unit 12 , the main-shaft unit 153 , and the like are lubricated.

FIG. 14 is a view illustrating positions of horizontal lubricating holes of Example 3. As illustrated in FIG. 14 , first horizontal lubricating holes 156 e of Example 3 are formed on the side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 . The first horizontal lubricating holes 156 e are formed as a horizontal through hole of the rotation shaft 15 in a 20° phase shifted direction (20° phase shifted direction from the neutral axis) from the eccentric direction (leftward side in FIG. 14 ) of the first eccentric portion 152 S in a direction opposite to the rotating direction (clockwise direction in FIG. 14 because the view is seen from below) of the rotation shaft 15 .

Therefore, as illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, the first horizontal lubricating holes 956 a and 956 b are positioned in a 40°-or-more phase shifted direction from the neutral axis. In contrast, the first horizontal lubricating hole 156 e of Example 3 is close to the neutral axis and tensile or compressive stress generated around the hole is small and thus, an advantage is achieved in stress reduction.

FIG. 15 is a view illustrating positions of horizontal lubricating holes of Example 4. As illustrated in FIG. 15 , first horizontal lubricating holes 156 g of Example 4 are formed on the side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 . Further, the first horizontal lubricating holes 156 g are formed as a horizontal through hole of the rotation shaft 15 in a 60° phase shifted direction (20° phase shifted direction from the neutral axis) from the eccentric direction (leftward side in FIG. 15 ) of the first eccentric portion 152 S in a direction opposite to the rotating direction (clockwise direction in FIG. 15 because the view is seen from below) of the rotation shaft 15 .

Therefore, as illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, the first horizontal lubricating holes 956 a and 956 b are positioned in a 40°-or-more phase shifted direction from the neutral axis. In contrast, the first horizontal lubricating holes 156 g of Example 4 are close to the neutral axis. Accordingly, tensile or compressive stress generated around the hole is small and thus, an advantage is achieved in stress reduction.

FIG. 16 is a view illustrating positions of horizontal lubricating holes of Example 5. As illustrated in FIG. 16 , first horizontal lubricating holes 156 i of Example 5 are formed on the side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 . The first horizontal lubricating holes 156 i are formed as a horizontal through hole of the rotation shaft 15 in a 70° phase shifted direction (30° phase shifted direction from the neutral axis) from the eccentric direction (leftward side in FIG. 16 ) of the first eccentric portion 152 S in a direction opposite to the rotating direction (clockwise direction in FIG. 16 because the view is seen from below) of the rotation shaft 15 .

Therefore, as illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, the first horizontal lubricating holes 956 a and 956 b are positioned in a 40°-or-more phase shifted direction from the neutral axis. In contrast, the first horizontal lubricating hole 156 g of Example 4 is close to the neutral axis. Accordingly, tensile or compressive stress generated around the hole is small and thus, an advantage is achieved in stress reduction.

FIG. 17 is a view illustrating positions of horizontal lubricating holes of Example 6. As illustrated in FIG. 17 , first horizontal lubricating holes 156 k of Example 6 are formed on the side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 . The first horizontal lubricating holes 156 k are formed as a horizontal through hole of the rotation shaft 15 in a 80° phase shifted direction (40° phase shifted direction from the neutral axis) from the eccentric direction (leftward side in FIG. 17 ) of the first eccentric portion 152 S in a direction opposite to the rotating direction (clockwise direction in FIG. 17 because the view is seen from below) of the rotation shaft 15 .

As illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, the first horizontal lubricating hole 956 a is positioned in a 40° phase shifted direction from the neutral axis in the clockwise direction. In addition, a first horizontal lubricating hole 956 b is positioned in a 50° phase shifted direction from the neutral axis in the counterclockwise direction. Therefore, the same compressive stress is generated to one first horizontal lubricating hole 156 k of Example 6 as that to the first horizontal lubricating hole 956 a in the related art. However, tensile stress generated around the other first horizontal lubricating hole 156 k of Example 6 is less than the compressive stress generated around the first horizontal lubricating hole 956 b in the related art and thus the first horizontal lubricating holes 156 k have advantages in stress reduction.

FIG. 18 is a view illustrating positions of horizontal lubricating holes of Example 7. As illustrated in FIG. 18 , first horizontal lubricating holes 156 m of Example 7 are formed on the side of the sub-shaft unit 151 of the first eccentric portion 152 S of the rotation shaft 15 . The first horizontal lubricating holes 156 m are formed as a horizontal through hole of the rotation shaft 15 in a 10° phase shifted direction (50° phase shifted direction from the neutral axis) from the eccentric direction (leftward side in FIG. 18 ) of the first eccentric portion 152 S in the rotating direction (clockwise direction in FIG. 18 because the view is seen from below) of the rotation shaft 15 .

As illustrated in FIG. 9 , in the rotary compressor in the related art which is disclosed in PTL 1, the first horizontal lubricating hole 956 a is positioned in a 40° phase shifted direction from the neutral axis in the clockwise direction. In contrast, the first horizontal lubricating hole 956 b is positioned in a 50° phase shifted direction from the neutral axis in the counterclockwise direction. Therefore, the same compressive stress is generated around the other first horizontal lubricating hole 156 m of Example 7 as that to the first horizontal lubricating hole 956 b in the related art. However, tensile stress generated around one first horizontal lubricating hole 156 m of Example 7 becomes greater than the compressive stress generated around the first horizontal lubricating hole 956 a in the related and thus the first horizontal lubricating holes 156 m are disadvantageous in stress reduction.

A rotation angle in which the maximum load due to the compression reaction force of the refrigerant is applied to the first and second eccentric portions 152 S and 152 T of the rotation shaft 15 is about from 180° to 270° although the rotation angle is changed in accordance with an operation range set for the rotary compressor 1 . Hence, as described in Examples 1 to 6, the direction in which the vertical lubricating holes may be formed is between the same direction as the eccentric direction of the first and second eccentric portions 152 S and 152 T and a 80° phase shifted direction from the same direction as the eccentric direction in a direction opposite to the rotating direction of the rotation shaft 15 .

In addition, in Examples 1 to 6, the first and second horizontal lubricating holes 156 a, 156 b, 156 c, 156 d, 156 e, 156 g , 156 i, 156 k are the horizontal through holes of the rotation shaft 15 . However, in a case where the horizontal through hole is not needed because of lubricating performance, the horizontal lubricating holes may be provided as a horizontal lubricating hole on only one side, which communicates with the vertical lubricating hole 155 .