Patent Description:
A rotary compressor is classified into a rotary compressor type in which a vane is slidably inserted into a cylinder to be in contact with a roller, and a rotary compressor type in which a vane is slidably inserted into a roller to be in contact with a cylinder. In general, the former is called a rotary compressor with an eccentric roller (hereinafter referred to as a "rotary compressor"), and the latter is called a concentric vane rotary compressor (hereinafter referred to as a "vane rotary compressor").

As for a rotary compressor, a vane inserted in a cylinder is pulled out toward a roller by elastic force or back pressure to come into contact with an outer circumferential surface of the roller. On the other hand, for a vane rotary compressor, a vane inserted in a roller rotates together with the roller, and is pulled out by centrifugal force and back pressure to come into contact with an inner circumferential surface of a cylinder.

A rotary compressor independently forms as many compression chambers as the number of vanes per revolution of a roller, and the compression chambers simultaneously perform suction, compression, and discharge strokes. On the other hand, a vane rotary compressor continuously forms as many compression chambers as the number of vanes per revolution of a roller, and the compression chambers sequentially perform suction, compression, and discharge strokes. Therefore, the vane rotary compressor provides a higher compression ratio than the rotary compressor. Therefore, the vane rotary compressor is more suitable for high pressure refrigerants such as R32, R410a, and CO2, which have low ozone depletion potential (ODP) and global warming index (GWP).

The vane rotary compressor is generally configured such that a center of the roller matches a center of the rotating shaft. Thus, the vane rotary compressor may be referred to as a concentric vane-type rotary compressor. Hereinafter, the concentric vane-type rotary compressor is defined as a vane rotary compressor in the description.

The vane rotary compressor is disclosed in patent document <NUM> (Japanese Patent Publication No.: <CIT>) and patent document <NUM> (Japanese Patent Publication No.: <CIT>). The vane rotary compressor in the patent document <NUM> discloses an example in which a roller is manufactured integrally with a rotating shaft.

The patent document <NUM> discloses an example in which a roller and a rotating shaft are separately manufactured, and then, post-assembled with each other. In this case, an outer circumferential surface of the rotating shaft and an inner circumferential surface of the roller are provided to have a circular shape to be press-fit, or machined to have a serration or gear shape to be pressed or press-fit. Alternatively, the roller and the rotating shaft may be coupled to each other using a fixing pin penetrating therethrough.

However, as described above, when the roller is manufactured integrally or post-assembled, the rotating shaft and the roller are provided as a single body. Thus, when magnetic centering such that a rotor is aligned with a center of a stator is performed, the roller axially moves with the rotating shaft coupled to the rotor. Then, as one axial side surface of the roller (i.e., an upper bearing surface) is brought into close contact with a thrust surface of a main bearing facing the upper bearing surface, friction loss or abrasion occurs. In addition, as a gap between the roller and a sub bearing is enlarged in correspondence with raising of the roller, leakage between compression chambers occurs, thereby deteriorating compression efficiency.

In addition, when the rotating shaft and the roller are manufactured as a single body as described above, the rotating shaft and the roller are manufactured using a same material. When the rotating shaft and the roller are separately machined and post-assembled as a single body, the rotating shaft and the roller are also manufactured using a same material or materials having similar rigidity and hardness in consideration of coupling reliability. Thus, as there are limits in selecting a material of the roller and reducing a weight of the roller, motor efficiency may not be increased.

In addition, as described above, when the rotating shaft and the roller are post-assembled as a single body, since a change in a post-assembly process may occur, the rotating shaft and the roller are assembled, and then, post-machined. In other words, primary processing of separately machining the rotating shaft and the roller is performed, then, the rotating shaft and the roller on which the primary machining is performed are post-assembled, and then, secondary machining of grinding a vane slot and a cross section and an outer circumferential surface with respect to the roller is performed. Thus, as machining time increases, a manufacture cost may increase.

<CIT>, an Art <NUM>(<NUM>) EPC document, presents a rotary compressor that includes a casing, a cylinder, a main bearing, a sub bearing, a rotating shaft, a roller having a vane slot and a back pressure chamber, and at least one vane. The roller includes a spring insertion groove formed in an inner end portion of the vane slot in a slot direction, and a vane spring supporting a rear surface of the vane toward an inner circumferential surface of the cylinder may be disposed in the spring insertion groove.

<CIT> presents a rotary compressor comprising a vertical rotational shaft including at least one protrusion formed on an outer peripheral surface, first and second bearings configured to support the rotational shaft in a radial direction, a cylinder disposed between the first and second bearings to form a compression space, a rotor disposed in the compression space and coupled to the rotational shaft to compress a refrigerant as the rotor rotates, and at least one vane slidably inserted into the rotor, the at least one vane coming into contact with an inner peripheral surface of the cylinder to separate the compression space into a plurality of regions. The rotor comprises at least one groove formed on an inner peripheral surface and faces the at least one protrusion and the rotation shaft is vertically movable relative to the rotor.

<CIT> presents seal for the rotor of rotary piston machines. The parting line or groove between the piston halves of the rotor of a rotary piston engine are sealed by means of foils which conform to the configuration of a peripheral portion of the rotor and cover the parting line or joint.

<CIT> presents a scroll compressor that includes a rotation shaft; a first scroll and a second scroll engaged with the first scroll to form a compression chamber between the second scroll and the first scroll. The second scroll includes a key recess. The scroll compressor includes an Oldham ring having a ring portion and a key portion protruding toward the key recess, from the ring portion. The key portion is coupled to the key recess in a sliding manner such that the second scroll orbits with respect to the first scroll. The scroll compressor also includes a wear preventing member installed between the key recess and the key portion. The second scroll includes an axial direction separation prevention groove formed by recessing one surface off the key recess. The wear preventing member includes an axial direction separation prevention portion held in place by the axial direction separation prevention groove.

<CIT> discloses a rotary compressor in which an eccentric roller is connected to a shaft, which has no eccentric portions, so that they do not move relative to each other and thereby ensure that no abrasion occurs between the rotating shaft and the roller.

It is an object of the present invention to provide a rotary compressor configured to suppress friction loss or abrasion between a roller and a bearing axially facing the roller, and also suppress leakage between compression chambers through a gap between the roller and a sub bearing.

It is an object of the present invention to provide a rotary compressor in which the roller is post-assembled with a rotating shaft and the roller is coupled to perform a relative motion with respect to the rotating shaft.

It is an object of the present invention to provide a rotary compressor in which the roller may perform a relative motion with respect to the rotating shaft and a relative motion range of the roller may be limited.

It is an object of the present invention to provide a rotary compressor in which a roller and a rotating shaft are post-assembled, and an assembly structure of the rotating shaft may be simplified.

It is an object of the present invention to provide a rotary compressor in which the roller and the rotating shaft are post-assembled, and the roller or the rotating shaft may be easily machined.

It is an object of the present invention to provide a rotary compressor in which a tolerance of the roller and the rotating shaft is ensured so that post-machining after post-assembly may not be performed.

It is an object of the present invention to provide a rotary compressor such that a weight of the roller may be reduced to increase compression efficiency.

It is an object of the present invention to provide a rotary compressor in which the roller and the rotating shaft may include different materials to reduce a weight of the roller.

It is an object of the present invention to provide a rotary compressor in which the roller and the rotating shaft include different materials, but coupling reliability is enhanced.

According to the present invention, as defined in independent claim <NUM>, a rotary compressor includes a casing, a driving motor, a rotating shaft, a main bearing and a sub bearing, a cylinder, a roller, a vane, and a rotation preventing unit. The driving motor is included inside the casing. The rotating shaft is coupled to a rotor in the driving motor and transmit rotational force. The main bearing and the sub bearing support the rotating shaft. The cylinder is provided between the main bearing and the sub bearing to provide a compression space. The roller is provided with a shaft hole through which the rotating shaft penetrates and is inserted in an axial direction. The vane divides the compression space into a plurality of compression chambers. The rotation preventing unit is provided between an outer circumferential surface of the rotating shaft and an inner circumferential surface of an shaft hole in the roller, the inner circumferential surface facing the outer circumferential surface of the rotating shaft, to constrain rotation of the roller with respect to the rotating shaft. The rotation preventing unit allows axial movement of the roller with respect to the rotating shaft. Thus, axial movement of the roller along a rotating shaft may be suppressed, and friction loss and abrasion between the roller and a main bearing or between the roller or a sub bearing may be suppressed.

The rotation preventing unit include a rotation preventing groove and a rotation preventing key.

The rotation preventing groove is provided in an inner circumferential surface of the shaft hole.

The rotation preventing key is provided on the outer circumferential surface of the rotating shaft and slidably inserted into the rotation preventing groove in an axial direction.

The rotation preventing key may be post-assembled on the rotating shaft. Thus, the rotation preventing key constituting the rotation preventing unit may be easily provided on the rotating shaft.

In detail, a key accommodating groove may be provided in the outer circumferential surface of the rotating shaft.

The rotation preventing key may be inserted and coupled into the key accommodating groove. Thus, the rotation preventing key may be easily coupled to the rotating shaft, and coupling stability may be also enhanced.

The rotation preventing unit includes a rotation preventing groove and a rotation preventing key.

The rotation preventing key may extend integrally from the rotating shaft. Thus, assembly of the rotation preventing unit including the rotation preventing key may be simplified.

The shaft hole may be also called axial hole and extends in radial direction through the roller.

An axial length of the rotation preventing key may extend longer than a circumferential width of the rotation preventing key. Thus, a circumferential area of the rotation preventing key may be greatly reduced, and rotational force may be stably transmitted to the roller.

In detail, the axial length of the key accommodating key may be provided to be equal to or less than an axial length of the rotation preventing groove.

Thus, during axial movement of the rotating shaft, the rotation preventing key may be suppressed from being hooked on a main bearing or a sub bearing.

As another example, the outer circumferential surface of the rotating shaft may be provided with a roller support surface configured to limit the axial movement of the roller and have a height difference relative to the outer circumferential surface of the rotating shaft.

Thus, the rotating shaft may be axially supported by the roller to enhance assembly stability and, simultaneously, limit axial movement of the roller to suppress friction loss and abrasion between the roller and a bearing.

In detail, the roller support surface may be arranged adjacent to the driving motor with reference to an axial center of the roller. Thus, excessive ascending of the roller toward a main bearing located at an upper side may be suppressed to reduce friction loss and abrasion between the roller and the main bearing.

In detail, the roller support surface may be provided to have an annular shape. Thus, the rotating shaft and the roller are uniformly supported in a circumferential direction to stably support the rotating shaft or the roller in an axial direction.

The rotation preventing groove is provided in an inner circumferential surface of the shaft hole. The rotation preventing key is arranged on the outer circumferential surface of the rotating shaft and slidably inserted into the rotation preventing groove in an axial direction.

One axial end of the rotation preventing groove is open and another axial end thereof may be closed to provide a hooking surface to limit axial movement of the rotation preventing key. Thus, the rotating shaft may be axially supported by the roller to enhance assembly stability and, simultaneously, limit axial movement of the roller to suppress friction loss and abrasion between the roller and a bearing.

In detail, the hooking surface may be provided at an end portion far apart from the driving motor with reference to the axial center of the roller. Thus, excessive ascending of the roller toward a main bearing located at an upper side may be suppressed to reduce friction loss and abrasion between the roller and the main bearing.

As another example, the roller may include a material having lower rigidity or hardness compared to the rotating shaft. Thus, a weight of the roller may be reduced, thereby reducing load on the driving motor.

In detail, the rotation preventing unit includes a rotation preventing groove and a rotation preventing key.

A first reinforcing member is provided between an inner circumferential surface of the rotation preventing groove and an outer circumferential surface of the rotation preventing key.

The first reinforcing member may include a material having higher rigidity or hardness compared to the roller. Thus, the roller may include a material lighter than that of the rotating shaft, and abrasion resistance may be also increased to ensure reliability of the rotation preventing unit.

In detail, a vane slot may be provided in an outer circumferential surface of the roller, the vane being inserted into the vane slot.

A second reinforcing member is inserted into the vane slot.

The second reinforcing member may include a material having higher rigidity or hardness compared to the roller. Thus, the roller may include a light material, and abrasion resistance between the vane and the vane slot may be also increased to ensure compressor performance.

As still another example, a back pressure pocket communicating with the inside of the casing may be on at least one from among a sliding surface of the main bearing and a sliding surface of the sub bearing, the sliding surface of the main bearing facing one axial side surface of the roller and a sliding surface of the sub bearing facing another axial side surface of the roller. Therefore, excessive axial movement of the roller due to pressure of oil in the back pressure pocket may be suppressed, and thus, friction loss and abrasion between the roller and a bearing facing the roller may be suppressed.

In detail, the back pressure pocket may at least partially overlap the rotation preventing unit in an axial direction. Thus, the oil in the back pressure pocket may flow into the rotation preventing unit to smoothly lubricate between the rotation preventing groove and the rotation preventing key both included in the rotation preventing unit.

In the rotary compressor according to the present invention, the inner circumferential surface of the cylinder may be formed in an elliptical shape.

In the rotary compressor according to the present invention, the inner circumferential surface of the cylinder may be formed in a circular shape.

Description will now be given in detail of a vane rotary compressor according to exemplary implementations disclosed herein, with reference to the accompanying drawings, of which only <FIG>, <FIG> and <FIG> disclose the implementation covered by the independent claim <NUM>, while the implementations shown in the other drawings are useful for the understanding of the invention or show other features.

The present invention provides a roller assembled with a rotating shaft and coupled thereto to be movable in an axial direction within a certain range. This may apply to not only a vane rotary compressor in which a vane is slidably inserted into a roller, but also a general rotary compressor in which a vane is slidably inserted into a cylinder. Hereinafter, a vane rotary compressor is described as a representative example.

<FIG> is a cross-sectional view illustrating one implementation of the vane rotary compressor according to the present invention, <FIG> is an exploded perspective view illustrating a compression unit of <FIG>, and <FIG> is an assembled planar view of the compression unit in <FIG>.

Referring to <FIG>, a vane rotary compressor according to this implementation includes a casing <NUM>, a driving (or drive) motor <NUM>, a rotating shaft <NUM>, and a compression unit <NUM>. The driving motor <NUM> is installed in an upper (a first) inner space 110a of the casing <NUM>, and the compression unit <NUM> is installed in a lower (a second) inner space 110a of the casing <NUM>. The driving motor <NUM> and the compression unit <NUM> are connected through a rotating shaft <NUM>.

The casing <NUM> that defines an outer appearance of the compressor may be classified as a vertical type and a horizontal type according to a compressor installation method. As for the vertical type casing, the driving motor <NUM> and the compression unit <NUM> are disposed at upper and lower sides in an axial direction, respectively. As for the horizontal type casing, the driving motor <NUM> and the compression unit <NUM> are disposed at left and right sides, respectively. The casing according to this implementation may be illustrated as the vertical type. Thus, the driving motor <NUM> and the compression unit <NUM> may also disposed in a first and second inner space of the casing respectively.

The casing <NUM> includes an intermediate shell <NUM> having a cylindrical shape, a lower (second) shell <NUM> covering a lower (second) end of the intermediate shell <NUM>, and an upper (first) shell <NUM> covering an upper (second) end of the intermediate shell <NUM>. In the following the terms lower and upper will be used in view of the illustration in the drawings. However, the lower and upper shell may be also designated second and first shell, respectively.

The driving motor <NUM> and the compression unit <NUM> may be inserted into the intermediate shell <NUM> to be fixed thereto. A suction pipe <NUM> may penetrate through the intermediate shell <NUM> to be directly connected to the compression unit <NUM>. The lower shell <NUM> may be coupled to the lower end of the intermediate shell <NUM> in a sealing manner. An oil storage space 110b in which oil to be supplied to the compression unit <NUM> is stored may be formed mainly in the lower shell <NUM> below the compression unit <NUM>.

The upper shell <NUM> may be coupled to the upper end of the intermediate shell <NUM> in a sealing manner. An oil separation space 110c may be formed above the driving motor <NUM> to separate oil from refrigerant discharged from the compression unit <NUM>.

The driving motor <NUM> that constitutes a motor unit supplies power to cause the compression unit <NUM> to be driven. The driving motor <NUM> includes a stator <NUM> and a rotor <NUM>.

The stator <NUM> may be fixedly inserted into the casing <NUM>. The stator <NUM> may be fixed to an inner circumferential surface of the casing <NUM> in a shrink-fitting manner or the like. For example, the stator <NUM> may be press-fitted into an inner circumferential surface of the intermediate shell <NUM>.

The rotor <NUM> may be rotatably inserted into the stator <NUM>, and the rotating shaft <NUM> may be press-fitted into a center of the rotor <NUM>. Accordingly, the rotating shaft <NUM> rotates concentrically together with the rotor <NUM>.

An oil flow path 130a having a hollow hole shape is provided in a central portion of the rotating shaft <NUM>. Oil passage holes 130b and 130c are provided through a middle portion of the oil flow path 130a toward an outer circumferential surface of the rotating shaft <NUM>. The oil passage holes 130b and 130c include a first oil passage hole 130b belonging to a range of a main bush portion <NUM> to be described later and a second oil passage hole 130c belonging to a range of a sub bush portion <NUM>. Each of the first oil passage hole 130b and the second oil passage hole 130c may be provided by one or in plurality. In this implementation, the first and second oil passage holes 130b, 130c are respectively provided in plurality.

An oil pickup 130d may be installed in a middle portion or a lower end of the oil flow path 130a. A gear pump, a viscous pump, a centrifugal pump, or the like may be used for the oil pickup 130d. In this implementation, a case in which the centrifugal pump is employed is illustrated. Accordingly, when the rotating shaft <NUM> rotates, oil filled in the oil storage space 110b is pumped by the oil pickup 130d and is sucked along the oil flow path 130a to be supplied into a sub bearing surface (no reference numeral) of the sub bush portion <NUM> through the second oil passage hole 130c and into a main bearing surface (no reference numeral) of the main bush portion <NUM> through the first oil passage hole 130b.

Meanwhile, the rotating shaft <NUM> may include a roller <NUM> to be described later. The roller <NUM> may extend integrally from the rotating shaft <NUM>. Alternatively, the rotating shaft <NUM> and the roller <NUM> may be separately manufactured, and then, post-assembled with each other. In this implementation, the rotating shaft <NUM> is inserted into the roller <NUM>, and then, post-assembled. For example, a shaft hole <NUM> may be penetrated through a center of the roller <NUM> in an axial direction and the rotating shaft <NUM> is inserted and coupled into the shaft hole <NUM>.

A rotation preventing key <NUM> is provided on an outer circumferential surface of the rotating shaft <NUM>, and a rotation preventing groove <NUM> is provided in an inner circumferential surface of the roller <NUM>, that is, an inner circumferential surface of the shaft hole <NUM>. The rotation preventing key <NUM> may protrude in a radial direction, and the rotation preventing groove <NUM> may be recessed in the radial direction so that the rotation preventing key <NUM> is inserted therein. Accordingly, the rotating shaft <NUM> and the roller <NUM> may be mutually constrained in a circumferential direction.

As illustrated in <FIG>, the rotation preventing key <NUM> and rotation preventing groove <NUM> may be provided between vane slots 1446a, 1446b, and 1446c to be described later, i.e., between two vane slots neighboring in a circumferential direction. In this case, the rotation preventing unit <NUM> including the rotation preventing key <NUM> and the rotation preventing groove <NUM> may be located in a middle position between the two vane slots. Accordingly, a circumferential side surface of the rotation preventing groove <NUM> may be prevented from being damaged by a circumferential force delivered through the rotation preventing groove <NUM>.

In addition, the rotation preventing key <NUM> and the rotation preventing groove <NUM> may be provided in positions that do not overlap the vane slots 1446a, 1446b, and 1446c in a circumferential direction. In other words, a virtual circle CL1 connecting an outer side surface of the rotation preventing groove <NUM> may be provided in a further inner position compared to the vane slots (back pressure chambers) 1446a, 1446b, and 1446c in a radial direction. Accordingly, by reducing a length by which the rotation prevention key <NUM> radially protrudes, a coupling reliability with respect to the rotation preventing key <NUM> may be enhanced.

Only one rotation preventing key <NUM> and one rotation preventing groove <NUM> may be provided as illustrated in the drawings, and in some cases, a plurality of rotation preventing keys <NUM> and a plurality of rotation preventing grooves <NUM> may be provided at equal intervals along the circumferential direction. A coupling relationship between the rotating shaft <NUM> and the roller <NUM> will be described later together with the roller <NUM>.

The compression unit <NUM> includes a main bearing <NUM>, a sub bearing <NUM>, a cylinder <NUM>, a roller <NUM>, and a plurality of vanes <NUM>, <NUM>, and <NUM>. The main bearing <NUM> and the sub bearing <NUM> are respectively provided at upper and lower parts of the cylinder <NUM> to define a compression space V together with the cylinder <NUM>, the roller <NUM> is rotatably installed in the compression space V, and the vanes <NUM>, <NUM>, and <NUM> are slidably inserted into the roller <NUM> to divide the compression space V into a plurality of compression chambers.

Referring to <FIG>, the main bearing <NUM> may be fixedly installed in the intermediate shell <NUM> of the casing <NUM>. For example, the main bearing <NUM> may be inserted into the intermediate shell <NUM> and welded thereto.

The main bearing <NUM> may be coupled to an upper end of the cylinder <NUM> in a close contact manner. Accordingly, the main bearing <NUM> defines an upper surface of the compression space V, and supports an upper surface of the roller <NUM> in the axial direction and at the same time supports an upper portion of the rotating shaft <NUM> in the radial direction.

The main bearing <NUM> may include a main plate portion <NUM> and a main bush portion <NUM>. The main plate portion <NUM> covers an upper part of the cylinder <NUM> to be coupled thereto, and the main bush portion <NUM> axially extends from a center of the main plate portion <NUM> toward the driving motor <NUM> so as to support the upper portion of the rotating shaft <NUM>.

The main plate portion <NUM> may have a disk shape, and an outer circumferential surface of the main plate portion <NUM> may be fixed to the inner circumferential surface of the intermediate shell <NUM> in a close contact manner. One or more discharge ports 1413a, 1413b, and 1413c may be formed in the main plate portion <NUM>, and a plurality of discharge valves <NUM>, <NUM>, and <NUM> configured to open and close the respective discharge ports 1413a, 1413b, and 1413c may be installed on an upper surface of the main plate portion <NUM>, and a discharge muffler <NUM> having a discharge space (no reference numeral) may be provided at an upper part of the main plate portion <NUM> to accommodate the discharge ports 1413a, 1413b, and 1413c, and the discharge valves <NUM>, <NUM>, and <NUM>.

A first main back pressure pocket 1415a and a second main back pressure pocket 1415b may be formed in a lower surface, namely, a main sliding surface 1411a of the main plate portion <NUM> facing the upper surface of the roller <NUM>, of both axial side surfaces of the main plate portion <NUM>.

The first main back pressure pocket 1415a and the second main back pressure pocket 1415b each having an arcuate shape may be disposed at a predetermined interval in a circumferential direction. Each of the first main back pressure pocket 1415a and the second main back pressure pocket 1415b may have an inner circumferential surface with a circular shape, but may have an outer circumferential surface with an oval or elliptical shape in consideration of vane slots to be described later.

The first main back pressure pocket 1415a and the second main back pressure pocket 1415b may be formed within an outer diameter range of the roller <NUM>. Accordingly, the first main back pressure pocket 1415a and the second main back pressure pocket 1415b may be separated from the compression space V. However, the first main back pressure pocket 1415a and the second main back pressure pocket 1415b may slightly communicate with each other through a gap between a lower surface, a main sliding surface 1411a of the main plate portion <NUM> and the upper surface of the roller <NUM> facing each other unless a separate sealing member is provided therebetween.

The first main back pressure pocket 1415a forms pressure lower than pressure formed in the second main back pressure pocket 1415b, for example, forms intermediate pressure between suction pressure and discharge pressure. Oil (refrigerant oil) may pass through a fine passage between a first main bearing protrusion 1416a to be described later and the upper surface of the roller <NUM> so as to be introduced into the first main back pressure pocket 1415a. The first main back pressure pocket 1415a may be formed in the range of a compression chamber forming intermediate pressure in the compression space V. This may allow the first main back pressure pocket 1415a to maintain the intermediate pressure.

The second main back pressure pocket 1415b may form pressure higher than that in the first main back pressure pocket 1415a, for example, discharge pressure or intermediate pressure between suction pressure close to the discharge pressure and the discharge pressure. Oil flowing into the main bearing hole 1412a of the main bearing <NUM> through the first oil passage hole 130b may be introduced into the second main back pressure pocket 1415b. The second main back pressure pocket 1415b may be formed in the range of a compression chamber forming a discharge pressure in the compression space V. This may allow the second main back pressure pocket 1415b to maintain the discharge pressure.

In addition, a first main bearing protrusion 1416a and a second main bearing protrusion 1416b may be formed on inner circumferential sides of the first main back pressure pocket 1415a and the second main back pressure pocket 1415b, respectively, in a manner of extending from the main bearing surface (no reference numeral) of the main bush potion <NUM>. Accordingly, the first main back pressure pocket 1415a and the second main back pressure pocket 1415b can be sealed from outside and simultaneously the rotating shaft <NUM> can be stably supported.

The first main bearing protrusion 1416a and the second main bearing protrusion 1416b may have the same height or different heights.

For example, when the first main bearing protrusion 1416a and the second main bearing protrusion 1416b have the same height, an oil communication groove (not illustrated) or an oil communication hole (not illustrated) may be formed on an end surface of the second main bearing protrusion 1416b such that inner and outer circumferential surfaces of the second main bearing protrusion 1416b can communicate with each other. Accordingly, high-pressure oil (refrigerant oil) flowing into the main bearing surface (no reference numeral) can be introduced into the second main back pressure pocket 1415b through the oil communication groove (not illustrated) or the oil communication hole (not illustrated).

On the other hand, when the first main bearing protrusion 1416a and the second main bearing protrusion 1416b have different heights, the height of the second main bearing protrusion 1416b may be lower than the height of the first main bearing protrusion 1416a. Accordingly, high-pressure oil (refrigerant oil) flowing into the main bearing hole 1412a can be introduced into the second main back pressure pocket 1415b by passing over the second main bearing protrusion 1416b.

Referring to <FIG>, the sub bearing <NUM> may be coupled to a lower end of the cylinder <NUM> in a close contact manner. Accordingly, the sub bearing <NUM> defines a lower surface of the compression space V, and supports a lower surface of the roller <NUM> in the axial direction and at the same time supports a lower portion of the rotating shaft <NUM> in the radial direction.

The sub bearing <NUM> may include a sub plate potion <NUM> and the sub bush portion <NUM>. The sub plate portion <NUM> may cover a lower part of the cylinder <NUM> to be coupled to thereto, and the sub bush portion <NUM> may axially extend from a center of the sub plate portion <NUM> toward the lower shell <NUM> so as to support the lower portion of the rotating shaft <NUM>.

The sub plate portion <NUM> may have a disk shape like the main plate portion <NUM>, and an outer circumferential surface of the sub plate portion <NUM> may be spaced apart from the inner circumferential surface of the intermediate shell <NUM>.

A first sub back pressure pocket 1425a and a second sub back pressure pocket 1425b may be formed on an upper surface, namely, a sub sliding surface 1421a of the sub plate portion <NUM> facing the lower surface of the roller <NUM>, of both axial side surfaces of the sub plate portion <NUM>.

The first sub back pressure pocket 1425a and the second sub back pressure pocket 1425b may be symmetric to the first main back pressure pocket 1415a and the second main back pressure pocket 1415b, respectively, with respect to the roller <NUM>.

For example, the first sub back pressure pocket 1425a and the first main back pressure pocket 1415a may be symmetric to each other, and the second sub back pressure pocket 1425b and the second main back pressure pocket 1415b may be symmetric to each other. Accordingly, a first sub bearing protrusion 1426a may be formed on an inner circumferential side of the first sub back pressure pocket 1425a, and a second sub bearing protrusion 1426b may be formed on an inner circumferential side of the second sub back pressure pocket 1425b.

Descriptions of the first sub back pressure pocket 1425a and the second sub back pressure pocket 1425b, and the first sub bearing protrusion 1426a and the second sub bearing protrusion 1426b are replaced by the descriptions of the first main back pressure pocket 1415a and the second main back pressure pocket 1416b, and the first main bearing protrusion 1416a and the second main bearing protrusion 1316b.

However, in some cases, the first sub back pressure pocket 1425a and the second sub back pressure pocket 1425b may be asymmetric to the first main back pressure pocket 1415a and the second main back pressure pocket 1415b, respectively, with respect to the roller <NUM>. For example, the first sub back pressure pocket 1425a and the second sub back pressure pocket 1425b may be formed to be deeper than the first main back pressure pocket 1415a and the second main back pressure pocket 1415b, respectively.

Although not illustrated in the drawings, the back pressure pockets 1415a, 1415b, 1425a, 1425b may be provided only at any one of the main bearing <NUM> and the sub bearing <NUM>.

Meanwhile, the discharge port <NUM> may be formed in the main bearing <NUM> as described above. However, the discharge port may be formed in the sub bearing <NUM>, formed in each of the main bearing <NUM> and the sub bearing <NUM>, or formed by penetrating between inner and outer circumferential surfaces of the cylinder <NUM>. This implementation describes an example in which the discharge ports <NUM> are formed in the main bearing <NUM>.

Referring to <FIG>, the cylinder <NUM> according to this implementation may be in close contact with a lower surface of the main bearing <NUM> and be coupled to the main bearing <NUM> by a bolt together with the sub bearing <NUM>. Accordingly, the cylinder <NUM> may be fixedly coupled to the casing <NUM> by the main bearing <NUM>.

The cylinder <NUM> may be formed in an annular shape having a hollow space in its center to define the compression space V. The hollow space may be sealed by the main bearing <NUM> and the sub bearing <NUM> to define the compression space V, and the roller <NUM> to be described later may be rotatably coupled to the compression space V.

The cylinder <NUM> may be provided with a suction port <NUM> penetrating from an outer circumferential surface to an inner circumferential surface thereof. However, the suction port may alternatively be formed through the main bearing <NUM> or the sub bearing <NUM>.

The suction port <NUM> may be formed on one side of the contact point P in the circumferential direction. The discharge port <NUM> described above may be formed through the main bearing <NUM> at another side of the contact point P in the circumferential direction that is opposite to the suction port <NUM>.

An inner circumferential surface <NUM> of the cylinder <NUM> may be formed in an elliptical shape. The inner circumferential surface <NUM> of the cylinder <NUM> according to this implementation may be formed in an asymmetric elliptical shape in which a plurality of ellipses, for example, four ellipses having different major and minor ratios are combined to have two origins.

For example, the inner circumferential surface <NUM> of the cylinder <NUM> according to the implementation may be defined to have a first origin O that is a center of the roller <NUM> or a center of rotation of the roller <NUM> (an axial center or a diameter center of the cylinder) or is biased by a first position from the center toward the contact point P, and a second origin O' biased from the first origin O toward the contact point P by a second position.

An X-Y plane formed around the first origin O may define a third quadrant Q3 and a fourth quadrant Q4, and an X-Y plane formed around the second origin O' may define a first quadrant Q1 and a second quadrant Q2. The third quadrant Q3 may be formed by a third ellipse, the fourth quadrant Q4 may be formed by a fourth ellipse, the first quadrant Q1 may be formed by the first ellipse, and the second quadrant Q2 may be formed by the second ellipse.

In addition, the inner circumferential surface <NUM> of the cylinder <NUM> may include a proximal portion 1432a, a remote portion 1432b, and a curved portion 1432c. The proximal portion 1432a is a portion closest to the outer circumferential surface <NUM> (or the center of rotation) of the roller <NUM>, the remote portion 1432b is a portion farthest away from the outer circumferential surface <NUM> of the roller <NUM>, and the curved portion 1432c is a portion connecting the proximal portion 1432a and the remote portion 1432b.

A point where the cylinder <NUM> and the roller <NUM> are closest to each other on the proximal portion 1432a may also be defined as the contact point P, and the first quadrant Q1 and the fourth quadrant Q4 may be divided based on the proximal portion 1432a. The suction port <NUM> may be formed in the first quadrant Q1 and the discharge port <NUM> may be formed in the fourth quadrant Q4, based on the proximal portion 1432a. Accordingly, when the vane <NUM>, <NUM>, <NUM> passes the contact point P, a compression surface of the roller <NUM> in the rotational direction may receive suction pressure as low pressure but an opposite compression rear surface may receive discharge pressure as high pressure. Then, while passing the contact point P, the roller <NUM> may receive the greatest fluctuating pressure between a front surface 1451a, 1452a, 1453a of each vane <NUM>, <NUM>, <NUM> that comes in contact with the inner circumferential surface of the cylinder <NUM> and a rear surface 1451b, 1452b, 1453b of each vane <NUM>, <NUM>, <NUM> that faces the back pressure chamber 1447a, 1447b, 1447c. This may cause tremor of the vane <NUM>, <NUM>, <NUM> significantly.

Accordingly, in this implementation, vane springs 1445a, 145b, and 1445c, which will be described later, may be disposed on the rear surfaces 1451b, 1452b, and 1453b of the vanes <NUM>, <NUM>, and <NUM>, respectively, to suppress the vanes <NUM>, <NUM>, and <NUM> from being pushed backwards in the vicinity of the contact point P, thereby preventing tremors of the vanes <NUM>, <NUM>, and <NUM> around the contact point P in advance. The vane springs 1445a, 145b, and 1445c will be described again later.

Referring to <FIG>, the roller <NUM> according to this implementation may be manufactured separately from the rotating shaft <NUM> and post-assembled with each other. The roller <NUM> may be manufactured using a same material as that of the rotating shaft <NUM>, or a material different therefrom. For example, the roller <NUM> may include a lighter and harder material compared to the rotating shaft <NUM>. In this case, a weight of a rotating body including the roller <NUM> may decrease to thereby reduce a load of the driving motor <NUM>.

The roller <NUM> may be provided as a single body, or an assembly type manufactured such that a plurality of separate parts of the roller <NUM> are manufactured, and then, assembled. In this implementation, an example in which the roller <NUM> is provided as a single body is described. However, even when the roller is provided as the assembly type, a basic shape of the roller <NUM> may be provided using a same method as that for a type of the single body.

The roller <NUM> according to the implementation may be rotatably disposed in the compression space V of the cylinder <NUM>, and the plurality of vanes <NUM>, <NUM>, <NUM> to be explained later may be inserted in the roller <NUM> at predetermined intervals along the circumferential direction. Accordingly, the compression space V may be partitioned into as many compression chambers as the number of the plurality of vanes <NUM>, <NUM>, and <NUM>. This implementation illustrates an example in which the plurality of vanes <NUM>, <NUM>, and <NUM> are three and thus the compression space V is partitioned into three compression chambers V1, V2, and V3.

An outer circumferential surface of the roller <NUM> may be provided as a discontinuous surface. For example, the roller <NUM> may have vane slots 1446a, 1446b, and 1446c, which will be described later. The vane slots 1346a, 1346b, and 1346c may be formed to be open to the outer circumferential surface of the roller body <NUM>. Accordingly, the outer circumferential surface of the roller <NUM> may be formed as a discontinuous surface due to open surfaces of the vane slots 1446a, 1446b, and 1446c.

The outer circumferential surface of the roller <NUM> may be formed in the circular shape as described above, and a rotation center Or of the roller <NUM> may be coaxially formed with an axial center (no reference numeral given) of the rotating shaft <NUM>. Accordingly, the roller <NUM> can concentrically rotate together with the rotating shaft <NUM>.

However, as described above, as the inner circumferential surface <NUM> of the cylinder <NUM> may be formed in the asymmetric elliptical shape biased in a specific direction, the rotation center Or of the roller <NUM> may be biased with respect to an outer diameter center Oc of the cylinder <NUM>. Accordingly, one side of the outer circumferential surface of the roller <NUM> may be almost brought into contact with the inner circumferential surface <NUM> of the cylinder <NUM>, precisely, the proximal portion 1432a, thereby defining the contact point P.

The contact point P may be formed in the proximal portion 1432a as described above. Accordingly, an imaginary line passing through the contact point P may correspond to a minor axis of an elliptical curve defining the inner circumferential surface <NUM> of the cylinder <NUM>.

The roller <NUM> may have the plurality of vane slots 1446a, 1446b, and 1446c, into which the vanes <NUM>, <NUM>, and <NUM> to be described later may be slidably inserted and coupled, respectively. The plurality of vane slots 1446a, 1446b, and 1446c may be provided at preset intervals along the circumferential direction. The outer circumferential surface 1341b of the roller <NUM> may have open surfaces that are open in the radial direction.

The plurality of vane slots 1446a, 1446b, and 1446c may be defined as a first vane slot 1446a, a second vane slot 1446b, and a third vane slot 1446c along a compression-progressing direction (the rotational direction of the roller). The first vane slot 1446a, the second vane slot 1446b, and the third vane slot 1446c may be formed at uniform or non-uniform intervals along the circumferential direction.

For example, each of the vane slots 1446a, 1446b, and 1446c may be inclined by a preset angle with respect to the radial direction, so as to secure a sufficient length of each of the vanes <NUM>, <NUM>, and <NUM>. Accordingly, when the inner circumferential surface <NUM> of the cylinder <NUM> is provided in the asymmetric elliptical shape, even when a distance from the outer circumferential surface 1341b of the roller body <NUM> to the inner circumferential surface <NUM> of the cylinder <NUM> increases, the separation of the vanes <NUM>, <NUM>, and <NUM> from the vane slots 1446a, 1446b, and 1446c may be suppressed, which may result in enhancing design freedom for the inner circumferential surface <NUM> of the cylinder <NUM> as well as that of the roller <NUM>.

A direction in which the vane slots 1446a, 1446b, and 1446c are inclined may be a reverse direction to the rotational direction of the roller <NUM>. That is, the front surfaces 1451a, 1452a, and 1453a of the vanes <NUM>, <NUM>, and <NUM> in contact with the inner circumferential surface <NUM> of the cylinder <NUM> may be tilted toward the rotational direction of the roller <NUM>. This may be preferable in that a compression start angle can be formed ahead in the rotational direction of the roller <NUM> so that compression can start quickly.

The back pressure chambers 1447a, 1447b, and 1447c may be formed to communicate with the inner ends of the vane slots 1446a, 1446b, and 1446c, respectively. The back pressure chambers 1447a, 1447b, and 1447c may be spaces in which oil (or refrigerant) of discharge pressure or intermediate pressure is filled to flow toward the rear sides of the vanes <NUM>, <NUM>, and <NUM>, that is, the rear surfaces 1451b, 1452b, and 1453b of the vanes <NUM>, <NUM>, <NUM>. The vanes <NUM>, <NUM>, and <NUM> may be pressed toward the inner circumferential surface of the cylinder <NUM> by the pressure of the oil (or refrigerant) filled in the back pressure chambers 1447a, 1447b, and 1447c. Hereinafter, a direction toward the inner circumferential surface of the cylinder based on a motion direction of the vane may be defined as the front, and an opposite side to the direction may be defined as the rear.

Although not illustrated in the drawings, the plurality of vane slots 1446a, 1446b, and 1446c may be provided in the radial direction, that is, radially with respect to the rotation center Or of the roller <NUM>. Even in this case, the rotation preventing groove <NUM> may be provided to be located between vane slots, precisely, apart from two neighboring vane slots by a same distance, respectively.

The back pressure chambers 1447a, 1447b, and 1447c may be hermetically sealed by the main bearing <NUM> and the sub bearing <NUM>, respectively. The back pressure chambers 1447a, 1447b, and 1447c may independently communicate with each of the back pressure pockets 1415a and 1415b, and 1425a and 1425b, and may also communicate with each other through the back pressure pockets 1415a and 1415b, and 1425a and 1425b.

The back pressure pockets 1415a and 1415b, and 1425a and 1425b may be provided to at least partially overlap the rotation preventing unit <NUM> in an axial direction. Accordingly, a part of oil flowing into the back pressure pockets 1415a and 1415b, and 1425a and 1425b may flow between the rotation preventing groove <NUM> and the rotation preventing key <NUM>, both included in the rotation preventing unit <NUM>, to effectively lubricate between the rotation preventing groove <NUM> and the rotation preventing key <NUM>.

Referring to <FIG>, a plurality of vanes <NUM>, <NUM>, and <NUM> according to this implementation may be slidably inserted into the respective vane slots 1446a, 1446b, and 1446c. Accordingly, the plurality of vanes <NUM>, <NUM>, and <NUM> may be provided to have substantially a same shape as the respective vane slots 1446a, 1446b, and 1446c.

For example, the plurality of vanes <NUM>, <NUM>, <NUM> may be defined as a first vane <NUM>, a second vane <NUM>, and a third vane <NUM> along the rotational direction of the roller <NUM>. The first vane <NUM> may be inserted into the first vane slot 1446a, the second vane <NUM> into the second vane slot 1446b, and the third vane <NUM> into the third vane slot 1446c, respectively.

The plurality of vanes <NUM>, <NUM>, and <NUM> may have substantially a same shape. For example, the plurality of vanes <NUM>, <NUM>, and <NUM> may each be formed in a substantially rectangular parallelepiped shape, and the front surfaces 1451a, 1452a, and 1453a of the vanes <NUM>, <NUM>, and <NUM> in contact with the inner circumferential surface <NUM> of the cylinder <NUM> may be provided to have a curved shape in the circumferential direction. Accordingly, the front surfaces 1451a, 1452a, and 1453a of the vanes <NUM>, <NUM>, and <NUM> may come into line-contact with the inner circumferential surface <NUM> of the cylinder <NUM>, thereby reducing friction loss.

In the vane rotary compressor having the hybrid cylinder, when power is applied to the driving motor <NUM>, the rotor <NUM> of the driving motor <NUM> and the rotating shaft <NUM> coupled to the rotor <NUM> rotate together, causing the roller <NUM> coupled to the rotating shaft <NUM> or integrally formed therewith to rotate together with the rotating shaft <NUM>.

Then, a plurality of the vanes <NUM>, <NUM>, and <NUM> may be drawn out of the vane slots 1446a, 1446b, and 1446c by centrifugal force generated by the rotation of the roller <NUM> and back pressure of the back pressure chambers 1447a, 1447b, and 1447c, which support the rear surfaces 1351b, 1353b, 1353b of the vanes <NUM>, <NUM>, and <NUM>, thereby being brought into contact with the inner circumferential surface <NUM> of the cylinder <NUM>.

Then, the compression space V of the cylinder <NUM> may be partitioned by the plurality of vanes <NUM>, <NUM>, and <NUM> into as many compression chambers (including suction chamber or discharge chamber) V1, V2, and V3 as the number of the vanes <NUM>, <NUM>, and <NUM>. The compression chambers v1, V2, and V3 may be changed in volume by the shape of the inner circumferential surface <NUM> of the cylinder <NUM> and eccentricity of the roller <NUM> while moving in response to the rotation of the roller <NUM>. Accordingly, refrigerant suctioned into the respective compression chambers V1, V2, and V3 may be compressed while moving along the roller <NUM> and the vanes <NUM>, <NUM>, and <NUM>, and discharged into the inner space of the casing <NUM>. Such series of processes may be repeatedly carried out.

As described above, the rotary compressor according to this implementation performs a type of 'magnetic centering' such that the rotating shaft <NUM> moves together with a rotor in an upward or downward axial direction according to magnetism of a driving motor during operation. In this case, when the roller <NUM> is provided integrally with the rotating shaft <NUM> or coupled thereto, both axial side surfaces of the roller <NUM> are in close contact with a main plate portion of the main bearing <NUM> or a sub plate portion of the sub bearing <NUM> facing the both axial side surfaces, respectively, thereby causing a friction loss or abrasion.

Particularly, when the compressor is started, the rotating shaft <NUM> ascends along with a rotor, and an upper axial surface 144a (hereinafter, referred to as an upper surface) of the roller <NUM> is in close contact with the main sliding surface 1411a of the main bearing <NUM>. Thus, an oil film may not be smoothly provided on the upper surface 144a of the roller <NUM>, thereby causing friction loss or abrasion. On the other hand, a clearance may be greatly generated between a lower axial surface 144b (hereinafter, referred to as a lower surface) of the roller <NUM> and the sub sliding surface 1421a of the sub bearing <NUM>. Thus, leakage between compression chambers may be caused or oil from the sub back pressure pockets 1425a and 1425b may excessively flow into a compression chamber, thereby deteriorating volumetric efficiency.

Thus, in this implementation, the rotating shaft <NUM> and the roller <NUM> are assembled for relative motion, and simultaneously, limit an ascending width of the roller <NUM> to suppress a friction loss or abrasion between the roller <NUM> and the main bearing <NUM> and ensure a sealing clearance between the roller <NUM> and the sub bearing <NUM>.

<FIG> is an exploded perspective view of the rotating shaft <NUM> and the roller <NUM> of <FIG>. <FIG> is an assembled perspective view of the rotating shaft <NUM> and the roller <NUM> of <FIG>. <FIG> is a cross-sectional view of <FIG>. <FIG> is an enlarged sectional view of the rotation preventing unit <NUM> of <FIG>.

Referring to <FIG>, an outer circumferential surface of the rotating shaft <NUM> and an inner circumferential surface of the shaft hole <NUM>, facing the outer circumferential surface of the rotating shaft <NUM>, include the rotation preventing unit <NUM> configured to prevent rotation of the roller <NUM> with respect to the rotating shaft <NUM>. Accordingly, even when the rotating shaft <NUM> and the roller <NUM> are separately manufactured, and then, post-assembled, rotational force of the driving motor <NUM> is transmitted to the roller <NUM> through the rotating shaft <NUM>, and the roller <NUM> may rotate with the rotating shaft <NUM> to compress refrigerant.

However, the rotation preventing unit <NUM> according to this implementation constrains the rotating shaft <NUM> and the roller <NUM> in a circumferential direction like being nearly coupled to each other, but not in an axial direction so that the rotating shaft <NUM> and the roller <NUM> are in a free state. In other words, the rotating shaft <NUM> and the roller <NUM> are nearly coupled to each other in a circumferential direction, but slidably coupled to each other in an axial direction.

In detail, the rotating preventing unit <NUM> according to this implementation includes the rotation preventing groove <NUM> and the rotation preventing key <NUM>.

The rotation preventing groove <NUM> is provided in an inner circumferential surface of the roller <NUM> and the rotation preventing key <NUM> is provided on an outer circumferential surface of the rotating shaft <NUM> to face each other. However, on a contrary to this, the rotation preventing groove <NUM> may be provided in the outer circumferential surface of the rotating shaft <NUM> and the rotation preventing key <NUM> may be provided on the inner circumferential surface of the roller <NUM>.

However, since a roller coupling unit <NUM> of the rotating shaft <NUM>, which will be described later, is located between the main bearing unit <NUM> and the sub bearing unit <NUM>, the former case may have more advantages compared to the latter case in terms of machining. Hereinafter, an example in which the rotation preventing groove <NUM> is provided in the inner circumferential surface of the roller <NUM> and the rotation preventing key <NUM> is provided on the outer circumferential surface of the rotating shaft <NUM> is described.

Referring to <FIG> and <FIG>, the rotation preventing groove <NUM> is provided to be radially recessed in the inner circumferential surface of the roller <NUM>. In other words, the shaft hole <NUM> may be provided at a center of the roller <NUM> such that the rotating shaft <NUM> is inserted into the shaft hole <NUM>, and the rotation preventing groove <NUM> described above is provided in the inner circumferential surface of the shaft hole <NUM> to be radially recessed to a preset depth.

The rotation preventing groove <NUM> is provided to terminate from the upper surface 144a to the lower surface 144b of the roller <NUM> in an axial direction. Accordingly, the rotation preventing groove <NUM> may be easily machined, and easily assembled into the rotation preventing key <NUM>.

The rotation preventing groove <NUM> may be provided to have a same cross-sectional area along an axial direction. Accordingly, the rotation preventing key <NUM> inserted into the rotation preventing groove <NUM> may also have a same cross-sectional area along an axial direction so that the roller <NUM> may smoothly move relative to the rotation shaft <NUM> in an axial direction.

The rotation preventing groove <NUM> may be provided have a shape corresponding to the rotation preventing key <NUM> to be described later. For example, the rotation preventing groove <NUM> may have a rectangular parallelepiped shape in which an axial length L21 is greater than a circumferential width L22. The rotation preventing groove <NUM> is provided to have a depth to overlap the rotation preventing key <NUM> to be described later in a circumferential direction. Accordingly, the rotation preventing key <NUM> to be described later may be slidably inserted into the rotation preventing groove <NUM> in the axial direction and the roller <NUM> may move relative to the rotating shaft <NUM> in an axial direction, but circumferential rotation of the roller <NUM> may be constrained so that the roller <NUM> may rotate together with the rotating shaft <NUM>.

The roller <NUM> is inserted into the cylinder <NUM>, and an axial height H3 of the roller <NUM> may be provided to be slightly less than an axial height H4 of the cylinder <NUM>, the axial height H4 being defined as a space between the main bearing <NUM> and the sub bearing <NUM>. Accordingly, the upper surface 144a of the roller <NUM> may be spaced apart from the main sliding surface 1411a of the main bearing <NUM> and the lower surface 144b of the roller <NUM> may be spaced apart from the sub sliding surface 1421a of the sub bearing <NUM> by preset clearances, respectively.

In other words, as illustrated in <FIG>, as the axial height H3 of the roller <NUM> is provided to be less than the axial height H4 of the cylinder <NUM>, the roller <NUM> is provided to be movable relative to the cylinder <NUM> in an axial direction, in a state of being separate from the rotating shaft <NUM>. Accordingly, a first clearance t1 between the upper surface 144a of the roller <NUM> and the main sliding surface 1411a of the main bearing <NUM>, and a second clearance t2 between the lower surface 144b of the roller <NUM> and the sub sliding surface 1421a of the sub bearing <NUM> are generated, and oil flows into the clearances t1 and t2 to provide an oil film. Thus, friction loss and abrasion in the first and second clearances t1 and t2 may be suppressed.

Referring to <FIG>, the rotation preventing key <NUM> according to this implementation protrudes from the outer circumferential surface of the rotating shaft <NUM> to the inner circumferential surface of the roller <NUM>, in other words, toward the rotation preventing groove <NUM> included in the inner circumferential surface of the shaft hole <NUM> by a preset height.

The rotation preventing key <NUM> may extend integrally from the outer circumferential surface of the rotating shaft <NUM>, or be post-assembled on the outer circumferential surface of the rotating shaft <NUM> to be coupled thereto. In this implementation, an example in which the rotation preventing key <NUM> is post-assembled on the outer circumferential surface of the rotating shaft <NUM> to be coupled thereto is described. Then, an example in which the rotation preventing key <NUM> extends integrally from the outer circumferential surface of the rotating shaft <NUM> will be described later as another implementation.

Referring to <FIG> and <FIG>, the key accommodating groove <NUM> is provided in the outer circumferential surface of the rotating shaft <NUM> such that the rotation preventing key <NUM> is inserted and coupled into the key accommodating groove <NUM>. The key accommodating groove <NUM> is provided between the main bearing unit <NUM> and the sub bearing unit <NUM> which will be described later. Accordingly, the rotation preventing key <NUM> is slidably inserted in an axial direction into the rotation preventing groove <NUM> of the roller <NUM> included in the main bearing unit <NUM> and the sub bearing unit <NUM>.

In detail, the outer circumferential surface of the rotating shaft <NUM> includes the main bearing unit <NUM>, the sub bearing unit <NUM>, the roller coupling unit <NUM>, and a roller support unit <NUM>. The main bearing unit <NUM> is accommodated in the main bearing hole 1412a of the main bearing <NUM>, the sub bearing unit <NUM> is accommodated in a sub bearing hole 1422a of the sub bearing <NUM>, and the roller coupling unit <NUM> is accommodated in the shaft hole <NUM> of the roller <NUM>. The roller support unit <NUM> is located between the main bearing unit <NUM> and the roller coupling unit <NUM>. According to a state of the rotating shaft <NUM>, a part of the roller support unit <NUM> may be accommodated in the main bearing hole 1412a of the main bearing <NUM>, and another part of the roller support unit <NUM> may be accommodated in the shaft hole <NUM> of the roller <NUM>.

An outer diameter D1 of the man bearing unit <NUM> is provided to be greater than an outer diameter D3 of the roller coupling unit <NUM>. The outer diameter D3 of the roller coupling unit <NUM> is provided to be greater than an outer diameter D2 of the sub bearing unit <NUM>. Accordingly, the roller <NUM> may be inserted in a direction from a lower end of the rotating shaft <NUM>, i.e., a lower end of the sub bearing unit <NUM> toward the main bearing unit <NUM>.

In this case, an outer diameter D4 of the roller support unit <NUM> located between the main bearing unit <NUM> and the roller coupling unit <NUM> is less than the outer diameter D1 of the main bearing unit <NUM> and greater than the outer diameter D3 of the roller coupling unit <NUM>. Accordingly, with reference to a portion between the roller coupling unit <NUM> and the roller support unit <NUM>, i.e., an axial direction center of the roller <NUM>, a roller support surface <NUM> may be provided to have a height difference at a side adjacent to the driving motor <NUM>.

Referring to <FIG>, the roller support surface <NUM> may be provided to have an annular shape. For example, the roller support surface <NUM> may be provided to have an annular shape having a same width along a circumferential direction. Accordingly, the rotating shaft <NUM> and the roller <NUM> may be uniformly in contact with each other on the roller support surface <NUM> along a circumferential direction so that the rotating shaft <NUM> may be stably supported by the roller <NUM>, or the roller <NUM> may be stably supported by the rotating shaft <NUM>. However, according to cases, the roller support surface <NUM> may be provided along a circumferential direction at a preset interval.

In detail, the roller support surface <NUM> may be provided such that the roller <NUM> is located in a middle portion between the main bearing <NUM> and the sub bearing <NUM> in a state when the stator <NUM> and the rotor <NUM> are aligned with each other due to magnetic centering. In other words, the roller support surface <NUM> may be provided in a position in which the first clearance t1 between the roller <NUM> and the main bearing <NUM> nearly matches the clearance t2 between the roller <NUM> and the sub bearing <NUM> in a state when a center of the stator <NUM> is arranged with that of the rotor <NUM>.

Accordingly, during operation of the compressor, the roller <NUM> is located approximately at a center between the main bearing <NUM> and the main bearing <NUM>. Then, the roller <NUM> may maintain a state of not being in contact with the main bearing <NUM> and the sub bearing <NUM>, thus minimizing friction loss or abrasion between the roller <NUM> and both of the main bearing <NUM> and the sub bearing <NUM>. When the compressor stops, the roller support surface <NUM> of the rotating shaft <NUM> is placed on an upper axial surface of the roller <NUM> to support the rotating shaft <NUM> in an axial direction.

The key accommodating groove <NUM> is provided in an outer circumferential surface of the roller coupling unit <NUM> such that the rotation preventing key <NUM> is inserted and fixed into the key accommodating groove <NUM>. Accordingly, the rotating shaft <NUM> may be easily machined, and the rotation preventing key <NUM> may be also easily provided on the rotating shaft <NUM>.

The key accommodating groove <NUM> is provided longitudinally in an axial direction to correspond to the rotation preventing key <NUM>. For example, an axial length L1 of the key accommodating groove <NUM> according to this implementation may be equal to or slightly greater than an axial length L21 of the rotation preventing key <NUM>. Accordingly, the rotation preventing key <NUM> may be easily assembled into the key accommodating groove <NUM>.

The key accommodating groove <NUM> may be provided to have a constant size along an axial direction. For example, a circumferential width and a radial depth of the key accommodating groove <NUM> may be provided to be constant along the axial direction. Thus, the key accommodating groove <NUM> may be easily machined, and assembly stability of the rotation preventing key <NUM> inserted into the key accommodating groove <NUM> may be enhanced. By doing so, rotational force may be stably and uniformly transmitted through the rotation preventing key <NUM>.

Referring to <FIG>, the rotation preventing key <NUM> according to this implementation is inserted and coupled into the key accommodating groove <NUM> described above. For example, the rotation preventing key <NUM> may be press-fit and fixed into the key accommodating groove <NUM>. Although not illustrated in the drawing, the rotation preventing key <NUM> may be fixedly coupled to the key accommodating groove <NUM> by an adhesive.

The rotation preventing key <NUM> may include a same material as that of the rotating shaft <NUM> or a material having rigidity or hardness similar to that of the rotating shaft <NUM>. Accordingly, the rotation preventing key <NUM> may transmit the rotational force to the roller <NUM> without being damaged in a state of being inserted into the key accommodating groove <NUM>.

However, the rotation preventing key <NUM> may include a material different from that of the rotating shaft <NUM>. For example, the rotation preventing key <NUM> may include a material having less rigidity or hardness compared to the rotating shaft <NUM>. In this case, the outer circumferential surface of the rotation preventing key <NUM> may be coated with a material having greater rigidity or hardness compared to the rotation preventing key <NUM> or a separate sliding member (not shown) may surround the rotation preventing key <NUM> to be coupled thereto. Accordingly, freedom of material selection for the rotation prevention key <NUM> may be increased, and rigidity of the rotation prevention key <NUM> may be also ensured.

The rotation preventing key <NUM> may have a shape corresponding to the rotation preventing groove <NUM>, e.g., a rectangular parallelepiped shape in which an axial length L31 is greater than a circumferential width L32. Accordingly, a circumferential area of the rotation preventing key <NUM> (or the rotation preventing groove) between the vane slots 1446a, 1446b, and 1446c may be minimized, and rotational force may also be uniformly transmitted to the roller <NUM> in the axial direction.

The rotation preventing key <NUM> may have a size same as or smaller than the rotation preventing groove <NUM>. For example, the axial length L31 of the rotation preventing key <NUM> may be provided to be equal to or less than the axial length L21 of the rotation preventing groove <NUM>. Accordingly, an axial moving distance of the rotating shaft <NUM> may be ensured to be greater than that of the roller <NUM>.

In detail, the axial length L31 of the rotation preventing key <NUM> may be equal to or less than the axial length L21 of the rotation preventing groove <NUM>. For example, the axial length L31 of the rotation preventing key <NUM> may be provided to be about <NUM> times less than the axial length L21 of the rotation preventing groove <NUM>. Accordingly, even when the rotating shaft <NUM> axially moves toward the stator <NUM> with the rotor <NUM> that is magnetic-centered, an upper end of the rotation preventing key <NUM> may be prevented from coming in contact with the main sliding surface 1411a of the main bearing <NUM>.

Thus, occurrence of friction loss or abrasion in the first clearance t1 between the upper surface 144a of the roller <NUM> and the main sliding surface 1411a of the main bearing <NUM> may be suppressed. In addition, leakage between compression chambers and an oil flow into a compression chamber through the second clearance t2 provided between the lower surface 144b of the roller <NUM> and the sub sliding surface 1421a of the sub bearing <NUM> may be obstructed. Accordingly, compression efficiency may be enhanced.

In addition, the circumferential length L32 of the rotation preventing key <NUM> may be provided to be less than the circumferential length L22 of the rotation preventing groove <NUM>. Accordingly, the outer circumferential surface of the rotation preventing key <NUM> may be inserted into the inner circumferential surface of the rotation preventing groove <NUM> to slide in an axial direction (refer to <FIG>).

In addition, a radial length H2 of the rotation preventing key <NUM> may be provided to be about two times or greater than the radial depth H1 of the key accommodating groove <NUM>. Accordingly, when the rotation preventing key <NUM> is inserted into the rotation preventing groove <NUM>, a part of an outer circumference of the rotation preventing key <NUM> protrudes, and the protruding part of the outer circumference is inserted into the rotation preventing groove <NUM> of the roller <NUM> to be described later. Thus, the rotating shaft <NUM> and the roller <NUM> may stably constrain each other with respect to a circumferential direction.

As described above, the rotation preventing key <NUM> may be provided to have a rectangular parallelepiped shape having a great axial length, and a sliding surface 152a may be provided respectively at upper and lower ends of the rotation preventing key <NUM>. For example, an inclined or curve-chambered sliding surface 152a may be provided respectively at circumferential corners of the upper and lower ends of the rotation preventing key <NUM>. Accordingly, abrasion between a lower corner of the rotation preventing key <NUM> and the sub sliding surface 1412a of the sub bearing <NUM>, facing the lower corner of the rotation preventing key <NUM>, may be suppressed when the compressor is started in a descending state of the rotating shaft <NUM>, or abrasion between the upper corner of the rotation preventing key <NUM> and the main sliding surface 1411a of the main bearing <NUM>, facing the upper corner of the rotation preventing key <NUM>, may be suppressed when the compressor is started in an ascending state of the rotating shaft <NUM>.

Although not illustrated in the drawing, the outer circumferential surface of the rotating shaft <NUM> and the inner circumferential surface of the roller <NUM> may be provided to have a D-cut section to match each other. In this case, the separate rotation preventing key <NUM> and rotation preventing groove <NUM>, described above, may not be provided.

As described above, an effect of the rotary compressor including the rotation preventing unit <NUM> according to this implementation is described below. <FIG> is a cross-sectional view illustrating a relation between the rotating shaft and the roller in a stop state of the compressor. <FIG> is a cross-sectional view illustrating a relation between the rotating shaft and the roller in an operation state of the compressor. In the drawings, a clearance between the roller and both of the bearings is exaggerated for convenience of description.

Referring to <FIG>, when the compressor is in a stop state, the rotating shaft <NUM> coupled to the rotor <NUM> descends due to a dead weight. In this case, since the rotation preventing key <NUM> coupled to the rotating shaft <NUM> is axially in a free state with respect to the rotation preventing groove <NUM>, the rotating shaft <NUM> slidably descends in an axial direction relative to the roller <NUM>.

Then, the first clearance t1 between the upper surface 144a of the roller <NUM> and the main sliding surface 1411a is nearly equal to an axial height difference between the roller <NUM> and the cylinder <NUM>, and the second clearance t2 between the lower surface 144b of the roller <NUM> and the sub sliding surface 1421a is nearly <NUM> (zero). In this case, as a lower end of the rotation preventing key <NUM> is in contact with the sub sliding surface 1421a of the sub bearing <NUM>, the rotating shaft <NUM> is axially supported. Simultaneously, the roller <NUM> descends separately from the rotating shaft <NUM> due to a dead weight, and thus, the lower surface 144b of the roller <NUM> is supported by the sub sliding surface 1421a of the sub bearing <NUM>.

Referring to <FIG>, when the compressor is in an operation state, the rotor <NUM> ascends according magnetic centering so that a center of the rotor <NUM> and a center of the stator <NUM> are aligned to have a same height. In this case, since the rotation preventing key <NUM> is axially in a free state with respect to the rotation preventing groove <NUM>, the rotating shaft <NUM> slidably ascends in an axial direction relative to the roller <NUM>.

Simultaneously, the roller <NUM> ascends separately from the rotating shaft <NUM> according to pressure of oil filled in the first sub back pressure pocket 1425a and the second sub back pressure pocket 1425b, both included in the sub bearing <NUM>. However, oil is also filled in the first main back pressure pocket 1415a and the second main back pressure pocket 1415b, both included in the main bearing <NUM>, and an ascending amount of the roller <NUM> is limited by the oil pressure. Accordingly, the roller <NUM> is spaced apart from the main bearing <NUM> and the sub bearing <NUM> due to pressure of the oil filled in the back pressure pockets 1415a and 1415b, and 1425a and 1425b of both of the bearings <NUM> and <NUM>.

In other words, a first clearance t1' between the upper surface 144a of the roller <NUM> and the main sliding surface 1411a is nearly equal to a second clearance t2' between the lower surface 144b of the roller <NUM> and the sub sliding surface 1421a. Thus, friction loss or abrasion between the upper surface 144a and the lower surface 144b of the roller <NUM>, and both the main and sub bearings <NUM> and <NUM> facing the upper and lower surfaces 144a and 144b may be suppressed.

Accordingly, rotational force of a rotating shaft is transmitted to a roller, and the roller is also suppressed from axially moving along the rotating shaft. Thus, friction loss or abrasion between the roller and bearings provided at both axial sides of the roller may be suppressed.

the rotating shaft is axially supported in a stop state of the compressor, and the roller is spaced apart from a main bearing and a sub bearing in an operation state of the compressor. Thus, friction loss or abrasion between the roller and the main and sub bearings may be effectively suppressed. In addition, a distance between the roller and the main bearing or between the roller and the sub bearing is constantly maintained. Thus, a leak between compression chambers or oil leakage from a back pressure pocket through a gap between the roller and the bearings is suppressed to thereby enhance compression efficiency or volumetric efficiency.

In addition, since a rotation preventing key is inserted and post-assembled into a key accommodating groove in the rotating shaft, the rotation preventing key may be easily provided. Also, an assembly structure of the roller and the rotating shaft may be simplified.

Further, as the roller rotates with the rotating shaft and the roller is slidably coupled to the rotating shaft, a tolerance between the roller and the rotating shaft may be ensured. Accordingly, after the roller and the rotation shaft are post-assembled, post-machining such as grinding may not be performed, and an assembly structure of the roller and the rotating shaft may be simplified.

Hereinafter, another implementation of the rotation preventing unit is described.

That is, in the implementation described above, a single-stage rotation preventing key is inserted and coupled into a key accommodating groove. However, according to cases, a multi-stage rotation preventing key may be inserted and coupled into the key accommodating groove.

<FIG> is an exploded perspective view illustrating another implementation of the rotation preventing key <NUM> of <FIG>. <FIG> is an assembled cross-sectional view of the implementation of <FIG>.

Referring to <FIG> and <FIG>, a basic configuration of the rotation preventing groove <NUM> and the rotation preventing key <NUM> both included in the rotation preventing unit <NUM> according to this implementation, and an effect resulting therefrom may be nearly identical to those of the implementation described above. For example, the key accommodating groove <NUM> may be provided in the rotating shaft <NUM>, and the rotation preventing key <NUM> is inserted and coupled into the key accommodating groove <NUM>. The rotation preventing key <NUM> is slidably inserted and coupled into the rotation preventing groove <NUM> in the inner circumferential surface of the roller <NUM> in an axial direction. Accordingly, the rotation preventing groove <NUM> and the rotation preventing key <NUM> may constrain each other in a circumferential direction, and be in a free state within a certain range in an axial direction. With respect to a detailed description thereof, the description about the implementation described above may be referred to.

However, in this implementation, the key accommodating groove <NUM> may be provided in multi-stages, and the rotation preventing key <NUM> may be also provided in multi-stages to correspond to the key accommodating groove <NUM>. For example, a fixing groove <NUM> may be provided at a center of the key accommodating groove <NUM>, and a fixing pin <NUM> may be provided on one radial side surface of the rotation preventing key <NUM>, and inserted and coupled into the fixing groove <NUM>.

The fixing groove <NUM> and the fixing pin <NUM> may be provided to correspond to each other such that the fixing pin <NUM> is inserted into the fixing groove <NUM>. For example, an inner diameter of the fixing groove <NUM> may be provided to be nearly equal to an outer diameter of the fixing pin <NUM>. Accordingly, the fixing pin <NUM> may be press-fit into the fixing groove <NUM>.

As described above, when the fixing groove <NUM> is provided in the key accommodating groove <NUM> and the fixing pin <NUM> is provided on and coupled to the rotation preventing key <NUM>, an area of contact between the key accommodating groove <NUM> and the rotation preventing key <NUM> is enlarged, thereby enhancing coupling reliability of the rotation preventing key <NUM>,.

In addition, even when an outer circumferential surface of the rotation preventing key <NUM> is not in close contact with an inner circumferential surface of the key accommodating groove <NUM>, the key preventing key <NUM> may maintain a state of being inserted into the key accommodating groove <NUM>. By doing so, assembling of the rotation preventing key <NUM> may be simplified.

Hereinafter, still another implementation of the rotation preventing unit is described.

That is, in the implementations described above, a roller and a rotating shaft include a same material. However, according to cases, the roller and the rotating shaft may be provided to include different materials.

<FIG> is an exploded perspective view illustrating another implementation of the roller of <FIG>. <FIG> is a planar view of a rotation preventing unit of <FIG>.

Referring to <FIG> and <FIG>, a basic configuration of the rotation preventing groove <NUM> and the rotation preventing key <NUM> both included in the rotation preventing unit <NUM> according to this implementation, and an effect resulting therefrom may be nearly identical to that of the implementation described above. For example, the key accommodating groove <NUM> may be provided in the rotating shaft <NUM>, and the rotation preventing key <NUM> is inserted and coupled into the key accommodating groove <NUM>. The rotation preventing key <NUM> is slidably inserted and coupled into the rotation preventing groove <NUM> provided in the inner circumferential surface of the roller <NUM> in an axial direction. Accordingly, the rotation preventing groove <NUM> and the rotation preventing key <NUM> may constrain each other in a circumferential direction, and be in a free state within a certain range in an axial direction. As a detailed description thereof, the implementation described above may be referred to.

However, in this implementation, the roller <NUM> and the rotating shaft <NUM> may be provided to include different materials. In other words, the rotating shaft <NUM> includes stainless steel, whereas the roller <NUM> may include a material lighter than that of the rotating shaft <NUM>, that is, a material lighter than stainless steel. Accordingly, by reducing a whole weight of the rotating shaft <NUM> including the roller <NUM> by reducing a weight of the roller <NUM>, motor efficiency may be enhanced.

The roller <NUM> may just need to include a material lighter than the rotating shaft. However, considering that the roller <NUM> is coupled to the rotation preventing key <NUM> of the rotating shaft <NUM>, the roller <NUM> may be provided to include a material with high rigidity as possible to ensure reliability.

A first reinforcing member <NUM> may be provided between the rotation preventing groove <NUM> and the rotation preventing key <NUM>. The first reinforcing member <NUM> may be provided to include a material having higher rigidity or hardness compared to the roller <NUM>. Thus, the roller <NUM> may include a light material and the rotation preventing groove <NUM> may be prevented from being crushed. By doing so, a state of coupling between the rotation preventing groove <NUM> and the rotation preventing key <NUM> may be stably maintained.

For example, the rotation preventing groove <NUM> may be provided in the inner circumferential surface of the roller <NUM> according to this implementation, and a reinforcing member including a material different from engineering plastic may be inserted into the inner circumferential surface of the rotation preventing groove <NUM>.

The roller <NUM> may include engineering plastic, and the first reinforcing member <NUM> may include a material having higher rigidity or hardness compared to engineering plastic. For example, the first reinforcing member <NUM> may include stainless steel same as that of the rotating shaft <NUM>.

The first reinforcing member <NUM> is provided to have a same cross-sectional shape as that of an inner circumferential surface of the rotation preventing groove <NUM> to be press-fit or attached to be coupled thereto. In this case, a step surface (no reference numeral) is provided at a lower end of the rotation preventing groove <NUM> to axially support a lower end of the first reinforcing member <NUM>.

Although not illustrated, the first reinforcing member (not shown) may be inserted into the outer circumferential surface of the rotation preventing key <NUM>. In this case, the roller <NUM> may be manufactured using a light material and the rotation preventing groove <NUM> may be prevented from being crushed to stably maintain a state of coupling between the rotation preventing groove <NUM> and the rotation preventing key <NUM>.

As described above, as the roller <NUM> and the rotating shaft <NUM> is manufactured as separate types, the roller <NUM> may be manufactured using a material lighter than the rotating shaft <NUM>. By doing so, a weight of the roller <NUM> may be reduced to decrease a load on a motor, thereby enhancing performance of the compressor.

In this case, the first reinforcing member <NUM> having high rigidity or hardness may be provided on the outer circumferential surface of the rotation preventing key <NUM> or the inner circumferential surface of the rotation preventing groove <NUM>. Thus, the roller <NUM> may include a material lighter than the rotating shaft <NUM>, and a coupling reliability between the roller <NUM> and the rotating shaft <NUM> may be ensured.

This may apply to between the roller and vanes. For example, a plurality of the vane slots 1446a, 1446b, and 1446c may be provided in the outer circumferential surface of the roller <NUM>, and second reinforcing members 1448a, 1448b, and 1448c may be press-fit or attached to be coupled to the vane slots 1446a, 1446b, and 1446c. Like the first reinforcing member <NUM>, the second reinforcing members 1448a, 1448b, and 1448c may be provided to include a material having rigidity or hardness higher than the roller <NUM>. Accordingly, the roller <NUM> may include a material lighter than the rotating shaft <NUM>, and vanes constituting a compression chamber may be stably supported.

That is, in the implementations described above, a roller support surface is provided on a rotating shaft. However, according to cases, a hooking surface may be provided on a roller.

<FIG> is a fractured perspective view illustrating the implementation of the present invention in line with independent claim <NUM> of the rotation preventing groove <NUM> of <FIG>. <FIG> is a cross-sectional view illustrating a relation between the rotating shaft <NUM> and the roller <NUM> in a stop state of the compressor of <FIG>. <FIG> is a cross-sectional view illustrating a relation between the rotating shaft <NUM> and the roller <NUM> in an operation state of the compressor of <FIG>.

Referring to <FIG>, a basic configuration of the rotation preventing groove <NUM> and the rotation preventing key <NUM> both included in the rotation preventing unit <NUM> according to this implementation, and an effect resulting therefrom may be nearly identical to that of the implementation described above. For example, the key accommodating groove <NUM> may be provided in the rotating shaft <NUM>, and the rotation preventing key <NUM> is inserted and coupled into the key accommodating groove <NUM>. The rotation preventing key <NUM> is slidably inserted and coupled into the rotation preventing groove <NUM> in the inner circumferential surface of the roller <NUM> in an axial direction. Accordingly, the rotation preventing groove <NUM> and the rotation preventing key <NUM> may constrain each other in a circumferential direction, and be in a free state within a certain range in an axial direction. With respect to a detailed description thereof, the description about the implementation described above may be referred to.

However, in this implementation, a hooking surface <NUM> for axially constraining the rotation preventing groove <NUM> to the rotation preventing key <NUM> is provided. For example, an upper end of the rotation preventing groove <NUM> adjacent to the stator <NUM> may be open in an axial direction, but a lower end thereof apart from the stator <NUM> may be closed in an axial direction. Accordingly, in this implementation, the roller support unit <NUM> and the roller support surface <NUM> is provided on the outer circumferential surface of the rotating shaft <NUM>. The hooking surface <NUM> is provided in the rotation preventing groove <NUM>, and the roller support surface <NUM> is provided on the rotating shaft <NUM> together. In this case, the rotating shaft <NUM> and the roller <NUM> may be stably supported.

As described above, as the hooking surface <NUM> is provided on the rotation preventing groove <NUM> to axially support the rotation preventing key <NUM>, a large radially overlapping area between the rotation preventing groove <NUM> and the rotation preventing key <NUM> may be ensured. By doing so, the rotating shaft <NUM> or the roller <NUM> may be stably supported.

For example, when the compressor is in a stop state, even when the rotating shaft <NUM> descends as illustrated in <FIG>, a lower end of the rotation preventing key <NUM> coupled to the rotating shaft <NUM> is supported by being placed on the hooking surface <NUM> included in the rotation preventing groove <NUM>. Then, the rotating shaft <NUM> is axially supported to maintain an assembly state.

In addition, when the compressor is in an operation state, even when the roller excessively ascends due to pressure in the sub back pressure pockets 1425a and 1425b, the hooking surface <NUM> on the rotation preventing groove <NUM> of the roller <NUM> is hooked on a lower end of the rotation preventing key <NUM> to limit an axial movement of the roller <NUM>. Then, excessively close contact between the upper surface 144a of the roller <NUM> and the main sliding surface 1411a of the main bearing <NUM> facing the upper surface 144a may be mechanically suppressed.

That is, in the implementations described above, a rotation preventing key is assembled on a rotating shaft. However, according to cases, the rotation preventing key may be provided integrally on the rotating shaft.

<FIG> is a perspective view illustrating another implementation of the rotation preventing key <NUM> of <FIG>. <FIG> is a planar view of <FIG>.

Referring to <FIG> and <FIG>, a basic configuration of the rotation preventing groove <NUM> and the rotation preventing key <NUM> both included in the rotation preventing unit <NUM> according to this implementation, and an effect resulting therefrom may be nearly identical to that of the implementations described above. For example, specifications of the rotation preventing groove <NUM> and the rotation preventing key <NUM> are nearly identical to those in the implementations described above. Thus, with respect to a detailed description thereof, the description about the implementation described above may be referred to.

However, in this implementation, the rotation preventing key <NUM> extend from the outer circumferential surface of the rotating shaft <NUM> in a radial direction. In other words, the rotation preventing key <NUM> extends to axially protrude from the roller coupling unit <NUM> of the rotating shaft <NUM>, and extend longitudinally in an axial direction. Accordingly, the rotation preventing key <NUM> of the rotating shaft <NUM> is inserted into the rotation preventing groove <NUM> of the roller <NUM> to constrain a circumferential direction between the roller <NUM> and the rotating shaft <NUM>.

Additionally, in this case, a root portion (no reference numeral) of the rotation preventing key <NUM> extending from the outer circumferential surface of the rotating shaft <NUM> may be curvedly provided. By doing so, the root portion of the rotation preventing key <NUM> may be suppressed from being damaged due to concentration of stress on the root portion.

As described above, when the rotation preventing key <NUM> is provided integrally with the rotating shaft <NUM>, an effect resulting therefrom is similar to that according to the implementation described above. In other words, as the rotation preventing key <NUM> of the rotating shaft <NUM> is slidably inserted into the rotation preventing groove <NUM> of the roller <NUM> in an axial direction, even when the rotating shaft <NUM> axially moves as described with reference to the above-mentioned implementations, axial movement of the roller <NUM> is minimized. Thus, friction loss or abrasion between the roller <NUM> and both the main and sub bearings <NUM> and <NUM> may be minimized.

In addition, like this implementation, when the rotation preventing key <NUM> is provided integrally with the rotating shaft <NUM>, a clearance may not occur between the rotating shaft <NUM> and the rotation preventing key <NUM> in a circumferential direction. Accordingly, rotational force of the rotating shaft <NUM> may be transmitted to the roller <NUM> simultaneously without delay.

In addition, like this implementation, when the rotation preventing key <NUM> is provided integrally with the rotating shaft <NUM>, the rotation preventing key <NUM> may not need to be assembled into the rotating shaft <NUM> separately. Thus, a working man hour for the rotation preventing unit <NUM> including the rotation preventing key <NUM> and the rotation preventing groove <NUM> may be reduced.

Although not illustrated, the rotation preventing key <NUM> and the rotation preventing groove <NUM> may be provided in plurality of pairs at uniform intervals along the circumferential direction. In this case, the roller <NUM> may be firmly coupled to the rotating shaft <NUM> to stably transmit a rotational force of the rotating shaft <NUM> to the roller <NUM>.

Claim 1:
A rotary compressor comprising:
a casing (<NUM>);
a driving motor (<NUM>) provided inside the casing;
a rotating shaft (<NUM>) coupled to a rotor (<NUM>) of the driving motor (<NUM>);
a main bearing (<NUM>) and a sub bearing (<NUM>) both supporting the rotating shaft (<NUM>);
a cylinder (<NUM>) provided between the main bearing (<NUM>) and the sub bearing (<NUM>) to provide a compression space (V);
a roller (<NUM>) having a shaft hole (<NUM>) through which the rotating shaft (<NUM>) penetrates;
a vane (<NUM>, <NUM>, <NUM>) dividing the compression space (V) into a plurality of compression chambers (V1, V2, V3); and
a rotation preventing unit (<NUM>) provided between an outer circumferential surface of the rotating shaft (<NUM>) and an inner circumferential surface of the shaft hole (<NUM>) in the roller (<NUM>), wherein the rotation preventing unit (<NUM>) allows an axial movement of the roller (<NUM>) with respect to the rotating shaft (<NUM>);
wherein the rotation preventing unit (<NUM>) comprises:
a rotation preventing groove (<NUM>) provided in an inner circumferential surface of the shaft hole (<NUM>); and
a rotation preventing key (<NUM>) provided on the outer circumferential surface of the rotating shaft (<NUM>) and slidably inserted into the rotation preventing groove (<NUM>) in an axial direction, characterized in that
an axial end of the rotation preventing groove (<NUM>) is open and another axial end of the rotation preventing groove (<NUM>) is closed to provide a hooking surface (<NUM>) to limit axial movement of the rotation preventing key (<NUM>).