CN111065824B - Rotary compressor - Google Patents

Abstract

The present invention relates to a rotary compressor, comprising: a drive motor; a rotating shaft; a main bearing and a sub bearing fixed to the housing and provided along the rotation axis; a cylinder barrel; a roller; and two or more blades, each of which has back pressure spaces formed along a predetermined radius on a bottom surface of the main bearing or a top surface of the sub bearing, and in which oil moving along the oil flow path is received in each of the back pressure spaces and pressure is transmitted to a rear end portion of each of the blades.

Description

Rotary compressor

Technical Field

The present invention relates to a Compressor, and more particularly, to a Rotary Compressor (Rotary Compressor) provided with blades.

Background

Generally, compressors may be classified into rotary type and reciprocating type according to the way of compressing refrigerant. The rotary compressor is a method in which the volume of a compression space is changed when a cylinder tube rotates or revolves, and the reciprocating compressor is a method in which the volume of a compression space is changed when a cylinder tube reciprocates. As a rotary compressor, a rotary compressor is known which compresses a refrigerant by rotating a piston by a rotational force of an electric motor.

Rotary compressors are continuously developing technologies related to high efficiency and miniaturization. In addition, a technology for satisfying more Cooling Capacity (Cooling Capacity) by increasing a variable range of an operation speed of a compressor in a case of miniaturization is being developed.

The rotary compressor may be divided into a single type rotary compressor and a double type rotary compressor according to the number of cylinder bores. The double rotary compressor can be classified into a system in which a plurality of cylinders are stacked to form a plurality of compression spaces and a system in which a plurality of compression spaces are formed in one cylinder.

The former is the following way: the plurality of rollers are provided on the rotary shaft with a height difference therebetween, and when the plurality of rollers perform eccentric rotation in the compression spaces of the respective cylinders, the refrigerant is alternately sucked into, compressed in, and discharged from the respective compression spaces. In this case, there is a disadvantage in that, as the plurality of cylinder bores are arranged in the axial direction, not only the size of the compressor is increased accordingly but also the material cost is increased.

Since the rotary compressor moves in a state where the tip end of the vane is in contact with the inner circumferential surface of the cylinder, only mechanical friction loss occurs during the compression of the refrigerant. In this regard, various developments for reducing mechanical friction loss are being made, and various attempts are being made to reduce the pressure acting on the back pressure chamber in which the rear end portion of the vane is located.

Fig. 1 and 2 are views illustrating an internal state of a conventional rotary compressor, showing a state of a compression unit located inside.

As shown in fig. 1, the conventional rotary compressor includes a casing 10, a driving motor (not shown), and a compression unit including a cylinder 33, a roller 34, a vane 35, a first bearing 31, and a second bearing 32. The refrigerant flowing into the cylinder 33 through the suction flow path (not shown) is compressed by the rotation of the vane 35, and then discharged through the discharge flow path (not shown).

The casing 10 has an external appearance, is provided with a compression unit therein, and compresses and discharges the refrigerant sucked by the compression unit. The refrigerant is sucked into and discharged from the cylinder 33 forming a compression space. Inside the cylinder 33, a roller 34 is provided, and the roller 34 rotates around the rotation shaft 23 and forms a plurality of compression spaces together with the blades 35. The roller 34 and the rotary shaft 23 perform concentric rotary motion.

Each vane 35 protrudes from a vane groove (not shown) and comes into contact with the inner circumferential surface of the cylinder 33 by a back pressure of oil formed at the rear end portion and a centrifugal force generated by rotation of the roller 34, and thereby forms a compression space in the inner space of the cylinder 33.

In the conventional rotary compressor, oil contained in the oil flow path 50 is supplied to the rear end of the vane 35 and acts on the rear end of the vane 35 to form a back pressure by the oil at the rear end of the vane 35. The oil flow path 50 is formed to penetrate the first bearing 31, the second bearing 32, and the cylinder 33, and is capable of moving high-pressure oil.

Each vane 35 protrudes from a vane groove (not shown) due to a back pressure of oil formed at the rear end portion and a centrifugal force caused by rotation of the roller 34, and is in close contact with the inner circumferential surface of the cylinder 33, whereby a compression space can be formed in the inner space of the cylinder 33.

The discharge pressure back pressure space 42 and the intermediate pressure back pressure space 41 are formed in the back pressure chamber (not shown). When the roller 34 rotates, the rear end portions of the vanes 35 communicate with back pressure chambers formed in the first bearing 31 and the second bearing 32, and discharge pressure or intermediate pressure can be applied.

First, a process in which the intermediate pressure acts on the rear end portion of the vane 358 will be described, in which high-pressure oil moves along the oil flow path 50, is accommodated in oil accommodating portions (not shown) formed at the left end of the first bearing 31 and the right end of the second bearing 32, and then moves to the intermediate pressure back pressure space 41 communicating with the rear end portion of the vane. Here, the high-pressure oil contained in the oil containing portion (not shown) moves to the intermediate-pressure back-pressure space 41 through the gaps between the bearings 31 and 32 and the outer peripheral surface of the rotary shaft 23 by the pressure. At this time, when the high-pressure oil moves to the intermediate-pressure back-pressure space 41 through the narrow gap, the pressure of the oil decreases, and therefore the rear end portions of the respective vanes are in communication with the intermediate-pressure back-pressure space 41 and receive the decreased pressure. That is, the back pressure chambers formed in the first bearing 31 and the second bearing 32 communicate with the rear end portions of the respective vanes, and can receive the pressure formed in the back pressure chamber 36.

Since the volume of the discharge-pressure back-pressure space 42 is smaller than the volume of the intermediate-pressure back-pressure space 41 and a sealed space is formed by separating the bearings 31 and 32 from each other, the pressure of the discharge-pressure back-pressure space 42 rises to be higher than the discharge pressure. For example, when the roller 34 rotates so that any of the vanes 35 passes through the discharge proceeding section, the distance between the tip of the vane 35 and the inner peripheral surface of the cylinder 33 becomes narrow and the vane 35 is pushed rearward, and the pressure in the discharge pressure back pressure space 42 increases greatly. When the pressure formed in the discharge pressure back pressure space 42 increases, a higher pressure acts on the rear end portion of the vane communicating with the discharge pressure back pressure space 42, and therefore, a high mechanical loss occurs between the vane and the cylinder, and there is a problem that the efficiency of the compressor decreases.

In particular, in the case of using a low-pressure refrigerant such as R-32, if it is desired to obtain the same level of freezing capacity as that of using a relatively high-pressure refrigerant such as R-134a or R-410a, it is necessary to increase the number of blades or increase the volume (or number) of the cylinder. However, if the number of the vanes is increased or the volume (or number) of the cylinder is increased, the friction area between the vanes and the cylinder is increased accordingly, and the mechanical friction loss is further increased.

Disclosure of Invention

Problems to be solved by the invention

The invention aims to provide a rotary compressor which is provided with a structure capable of restraining excessive increase of contact force between a blade and a cylinder barrel by adjusting pressure formed at the rear end of the blade.

It is another object of the present invention to provide a rotary compressor in which a discharge pressure back-pressure space is formed as an open space, and thereby, even in a section where the back pressure can be increased when the roller rotates, the pressure in the discharge pressure back-pressure space can be prevented from increasing to a pressure equal to or higher than the discharge pressure.

It is another object of the present invention to provide a rotary compressor having a structure capable of reducing pressure pulsation when an intermediate pressure is formed at a rear end portion of a vane.

It is another object of the present invention to provide a rotary compressor that can exhibit a refrigeration capacity equivalent to that of a case where a relatively high-pressure refrigerant is used even when a low-pressure refrigerant is used, and can suppress an increase in mechanical friction loss.

Technical scheme for solving problems

In order to achieve the above object of the present invention, a rotary compressor of the present invention includes: a housing; a drive motor; a rotating shaft; a roller rotating together with the rotating shaft and forming a compression space for compressing refrigerant between the roller and the inner circumferential surface of the cylinder tube; and two or more vanes which are in contact with the inner circumferential surface of the cylinder tube, divide the compression space into a suction chamber and a compression chamber, and transmit pressure to the rear end portions of the vanes by accommodating oil which moves along an oil flow path in a back pressure space formed in the bottom surface of the main bearing or the top surface of the sub-bearing. Therefore, the contact force between the vane and the cylinder can be reduced by adjusting the pressure formed at the rear end of the vane.

According to an embodiment related to the present invention, the back pressure space may be formed only in the bottom surface of the main bearing or only in the top surface of the sub-bearing, or the back pressure spaces may be formed in the bottom surface of the main bearing and the top surface of the sub-bearing, respectively. The back pressure space contains oil that moves along the oil flow path, and pressure can be transmitted to the rear end of the vane.

According to an embodiment of the present invention, back pressure spaces are formed along predetermined radii, and oil that moves along the oil flow path is received in the back pressure spaces, whereby pressure can be transmitted to the rear end portions of the vanes.

According to an embodiment related to the present invention, the back pressure space may be divided into a first back pressure space and a second back pressure space, respectively. The first back pressure space is formed along an arc of a predetermined length at a predetermined distance from the outer circumferential surface of the rotating shaft to form an intermediate pressure, and the second back pressure space is formed along an arc of a predetermined length to face the first back pressure space and to communicate with one side of the oil flow passage to form a pressure by the oil.

According to an embodiment related to the present invention, each of the vanes rotates together with the roller, and as the roller rotates, a rear end portion of each of the vanes is exposed to each of the back pressure spaces, whereby pressure formed in the first back pressure space or the second back pressure space can be received.

According to an embodiment related to the present invention, the oil flow path may include: a first oil flow path that moves high-pressure oil in a direction in which a center portion of the rotating shaft extends toward the rotating shaft; and a second oil flow passage communicating with the first oil flow passage, penetrating the rotary shaft, and formed in a direction intersecting the first oil flow passage.

According to an embodiment of the present invention, the oil that moves along the second oil flow path moves to the first back pressure space through the gap between the rotary shaft and the main bearing and the gap between the rotary shaft and the sub bearing to form an intermediate pressure.

According to an embodiment related to the present invention, the second oil flow path may transmit the pressure formed at the second oil flow path to the second back pressure space by communicating with the second back pressure space.

According to an embodiment related to the present invention, a compression chamber communication flow path may be formed in the interior of the main bearing or the interior of the sub bearing, respectively, so that one side of the first back pressure space communicates with the compression space of the cylinder tube.

According to an embodiment related to the present invention, a resonator communication flow path communicating one side of the first back pressure space and the resonator space of the cylinder tube may be formed inside the main bearing or inside the sub bearing, respectively.

According to an embodiment related to the present invention, the first back pressure space may be formed along an arc of a predetermined length, and may be divided into two or more space portions.

Effects of the invention

According to the rotary compressor configured as described above, the back pressure space for forming the discharge pressure is formed in the open structure, and thus the vane can be prevented from excessively coming into close contact with the inner circumferential surface of the cylinder tube between the discharge pressure spaces due to the back pressure. This reduces mechanical friction loss between the vane and the cylinder in the discharge pressure range, thereby improving compressor efficiency.

Further, the pressure in the back pressure space forming the intermediate pressure and the pressure in the compression chamber can be interlocked by communicating the back pressure space forming the intermediate pressure and the compression chamber forming the intermediate pressure. This reduces the mechanical friction loss between the blade and the cylinder in the intermediate pressure zone.

Further, by communicating the back pressure space that forms the intermediate pressure with the additional resonator space, the pressure pulsation of the back pressure space that forms the intermediate pressure can be reduced. This stabilizes the contact state between the blade and the cylinder as a whole, including the intermediate pressure zone.

Further, by forming a plurality of back pressure spaces for forming the intermediate pressure, the mechanical friction loss between the vane and the cylinder in the intermediate pressure section can be further reduced.

In addition, according to the embodiments described above, even when a low-pressure refrigerant is used, the refrigeration capacity can be exhibited as much as when a relatively high-pressure refrigerant is used, and an increase in mechanical friction loss can be suppressed.

Drawings

Fig. 1 is a sectional view showing the interior of a conventional rotary compressor.

Fig. 2 is a sectional view of a compression unit of the rotary compressor of fig. 1, viewed axially.

Fig. 3 is a sectional view showing a structure of a rotary compressor according to the present invention.

Fig. 4 is a sectional view taken along line iv-iv of fig. 3.

Fig. 5 is a cross-sectional view taken along line v-v of fig. 3.

Fig. 6 is a perspective view showing a main part of the compression unit shown in fig. 3 cut away.

Fig. 7A to 7D are operation state diagrams of the rotary compressor illustrating a process in which the refrigerant is compressed as the roller rotates.

Fig. 8 is a graph showing the magnitude of pressure formed in each back pressure space according to the rotation angle.

Fig. 9A is a sectional view illustrating another embodiment of a rotary compressor according to the present invention.

Fig. 9B is an enlarged view showing a state where the back pressure space communicates with the compression space.

Fig. 10 is a conceptual diagram illustrating a state in which the first back pressure space and the compression space communicate with each other through the compression chamber communication passage.

Fig. 11 is a graph showing the relationship between the pressure of each back pressure space and the pressure formed in the compression space according to the rotation angle.

Fig. 12A is a cross-sectional view showing a state in which the resonator space portion and the first back pressure space communicate with each other.

Fig. 12B is an enlarged view showing a state in which the resonator space portion and the first back pressure space communicate with each other.

Fig. 13 is a graph showing the relationship between the rotation angle and the pressure formed at the first back pressure space when the first back pressure space and the resonator space communicate with each other and when they do not communicate with each other.

Fig. 14 is a conceptual diagram showing a state where the first back pressure space is divided into two space portions.

Fig. 15 is a graph showing pressures formed by the first back pressure space and the second back pressure space in the compressor of fig. 14.

Fig. 16 is a sectional view showing a deformed structure of the compression space.

Fig. 17 is a sectional view showing another modified structure of the compression space.

Detailed Description

Hereinafter, a rotary compressor according to the present invention will be described in detail with reference to the accompanying drawings.

In this specification, the singular expressions shall include the plural expressions unless the context clearly indicates otherwise.

In describing the embodiments disclosed in the present specification, if it is determined that a specific description of the related known art may make the gist of the embodiments disclosed in the present specification unclear, a detailed description thereof will be omitted.

The drawings are only for the purpose of facilitating understanding of the embodiments disclosed herein, and the technical idea disclosed herein is not limited by the drawings, and it should be understood that the present invention includes the idea of the invention and all modifications, equivalents, and alternatives within the technical scope.

Fig. 3 is a sectional view showing a structure of the rotary compressor 100 according to the present invention.

The rotary compressor 100 includes a casing 110, a driving motor 120, and a compression unit. The casing 110 forms an external appearance of the compressor 100, and each component is mounted inside the casing 110, and the casing 110 serves to support the components. The housing 110 may be formed in a cylindrical shape extending in one direction, and may be formed in an extending direction of a rotation shaft 123 described later.

The case 110 may be composed of an upper case 110a, an intermediate case 110b, and a lower case 110 c. The driving motor 120 and the compression unit may be fixedly disposed at an inner side surface of the middle case 110 b. The upper case 110a and the lower case 110c are disposed at the upper and lower portions of the middle case 110b, respectively, thereby restricting exposure of the respective components located inside. The compression unit performs a function of compressing the refrigerant. The compression unit includes a roller 134, a blade 135, a cylinder 133, a main bearing 131, and a sub-bearing 132.

A suction pipe 113 is provided on one side of the intermediate casing 110b, and a discharge pipe 114 is provided on one side of the upper casing 110 a. The refrigerant can flow into the interior of the casing 110 or flow out to the outside through the suction pipe 113 and the discharge pipe 114.

In the refrigeration cycle, a rotary compressor, a condenser, an expander, and an evaporator are connected in this order. The suction pipe 113 is connected to the evaporator.

The suction port 111 is formed to penetrate the inside and outside of the cylinder 133. The suction port 111 communicates with the suction pipe 113 and the casing 110, and the condenser (not shown) communicates with an upper internal space of the rotary compressor 100 through the discharge pipe 114.

The discharge ports 112a and 112b are formed to penetrate the inside and outside of the cylinder 133. The discharge ports 112a and 112b communicate the compression space V with the outside of the compression unit. The high-pressure refrigerant discharged to the outside of the compression unit through the discharge ports 112a and 112b is discharged to the outside of the casing 110 through the discharge pipe 114.

A discharge valve 115 is provided at each of the discharge ports 112a and 112 b. The discharge valve 115 is formed to prevent the high-pressure refrigerant discharged through the discharge ports 112a and 112b from flowing back into the compression space V again.

The driving motor 120 plays a role of providing power for compressing the refrigerant. The driving motor 120 includes a stator 121, a rotor 122, and a rotation shaft 123.

The stator 121 is fixedly installed inside the housing 110, and can be attached to the inner circumferential surface of the cylindrical housing 110 by a method such as shrink fit. For example, the stator 121 may be fixedly disposed at an inner circumferential surface of the middle case 110 b.

The rotor 122 may be configured to be spaced apart from the stator 121 and located inside the stator 121. When power is applied to the stator 121, the rotor 122 is rotated by a force generated by a magnetic field formed between the stator 121 and the rotor 122. Accordingly, the rotary shaft 123 penetrating the center of the rotor 122 also rotates together with the rotor 122, and the power is transmitted to the roller 134 as the rotary shaft 123 rotates.

The compression unit performs a function of compressing the refrigerant. The compression unit includes a roller 134, a blade 135, a cylinder 133, a main bearing 131, and a sub-bearing 132.

The main bearing 131 and the sub bearing 132 are respectively located in the axial direction of the rotation shaft 123. The main bearing 131 and the sub bearing 132 each function as a closed compression space V. The main bearing 131 and the sub bearing 132 function to support the cylinder 133, the roller 134, and the blade 135, respectively. A first oil flow passage 151 formed to extend from a lower portion toward an upper portion in the axial direction is formed in a central portion of the rotary shaft 123. The high-pressure oil can move along the oil flow path 151 from the oil feeder 136 located at the lower portion of the rotation shaft 123.

The main bearing 131 and the sub-bearing 132 are fixedly provided to the housing 110 and are disposed to be spaced apart from each other along the rotation axis 123. The main bearing 131 and the sub bearing 132 function to support the cylinder tube 133 and the roller 134 at both ends of the rotating shaft 123 in the axial direction, respectively. The main bearing 131 is located at an upper portion of the cylinder 133, and the sub-bearing 132 is located at a lower portion of the cylinder 133. The main bearing 131 and the sub bearing 132 are fixed to the cylinder 133, and function to rotatably support the blades 135 and the rollers 134 inside the cylinder 133. Since the main bearing 131 and the sub bearing 132 are respectively positioned at the upper portion and the lower portion of the compression space V, the sealed state of the compression space V can be maintained.

The cylinder 133 and the main bearing 131 are fixedly coupled to each other, and the cylinder 133 and the sub-bearing 132 are fixedly coupled to each other. This makes it possible to seal the internal space of the compression unit. The internal space of the compression unit is referred to as a compression space V described later. In addition, the refrigerant accommodated in the inner space of the compression unit may be compressed in a sealed state by the rotation of the roller 134 and the vane 135.

A roller 134 is provided inside the cylinder 133, and the roller 134 rotates around the rotation shaft 123. A compression space V is formed between the roller 134 and the inner circumferential surface of the cylinder 133 so as to be able to compress the refrigerant accommodated in the inner space of the cylinder 133. The roller 134 and the rotation shaft 123 perform concentric rotation movement.

The blade 135 is inserted into the roller 134. The roller 134 is formed with a blade groove 134a capable of accommodating the blade 135. A back pressure chamber 137 is formed at the inner end of the vane groove 134 a. The vane grooves 134a are open to the outer peripheral surface of the roller 134. The vane 135 is provided to be able to enter and exit the vane groove 134 a. The number of the vane grooves 134a is the same as the number of the vanes 135, and a plurality of the vane grooves 134a may be formed. A back pressure chamber 137 is formed in each vane groove 134a, and the back pressure chamber 137 communicates with back pressure spaces 141 and 142 described later.

The vane 135 protrudes from the roller 134 by a pressure acting on a rear end portion of the vane 135 and a centrifugal force generated by rotation of the roller 134, and divides the compression space V into a suction chamber and a compression chamber by contacting an inner circumferential surface of the cylinder 133, respectively. A compression chamber is formed at a front side where the vane 135 moves, and a suction chamber is formed at a rear side of the vane 135. Here, the front end of the vane 135 contacts the inner circumferential surface of the cylinder 133, and the rear end of the vane 135 is a portion that receives the pressure formed in the back pressure spaces 141 and 142.

The blades 135 may be formed in two or more numbers, and the blades 135 may be disposed at predetermined intervals inside the roller 134. Here, the inside of the roller 134 refers to the vane groove 134a described previously.

The roller 134 coupled to the rotating shaft 123 rotates as the driving motor 120 rotates, and the vanes 135 provided inside the roller 134 protrude from the roller 134 and move in a state where the front end portions thereof contact the inner circumferential surface of the cylinder 133.

Back pressure spaces 141, 142 may be formed at a lower end of the main bearing 131 and/or an upper end of the sub bearing 132, respectively, and the back pressure spaces 141, 142 are formed as circular arc (circular arc) shaped grooves along a predetermined radius. The rear end portion of each vane 135 protrudes from the roller 134 by the pressure of each back pressure chamber 137 communicating with the inside of the back pressure spaces 141, 142 and comes into contact with the inner circumferential surface of the cylinder 133.

The oil moves along a first oil flow path 151 formed in the vertical direction at the center of the rotation shaft 123. The oil moving along the first oil flow path 151 may move along a second oil flow path 152 and flow into the back pressure spaces 141, 142, the second oil flow path 152 penetrating the rotation shaft 123 and being formed in a direction crossing a direction in which the rotation shaft 123 extends. This allows the rear end of each blade 135 exposed to the back pressure spaces 141 and 142 to be pressed.

The back pressure spaces 141, 142 may be formed of a first back pressure space 141 and a second back pressure space 142, respectively, and a discharge pressure or an intermediate pressure may be applied to the respective back pressure spaces 141, 142. Here, the discharge pressure refers to the pressure of the oil supplied by the oil feeder 136, and the intermediate pressure refers to a pressure lower than the discharge pressure and higher than the suction pressure.

The first back pressure space 141 and the second back pressure space 142 may be formed at positions spaced apart from the inner circumferential surfaces of the center portions of the main bearing 131 and the sub-bearing 132 by a predetermined interval.

The first back pressure space 141 and the second oil flow path 152 are spaced apart from each other. A boundary formed by the main bearing 131 and/or the sub-bearing 132 exists between the first back pressure space 141 and the second oil flow path 152. Accordingly, the first back pressure space 141 and the second oil flow path 152 do not directly communicate with each other. A pressure lower than the discharge pressure is formed in the first back pressure space 141.

In contrast, the second back pressure space 142 directly communicates with the second oil flow path 152. Therefore, the discharge pressure can be formed in the second back pressure space 142. However, the pressure of the oil is slightly reduced as it passes through the second oil flow path 152, and in this case, the pressure formed in the second back pressure space 142 is slightly lower than the discharge pressure.

In the present specification, the term "forming the discharge pressure in the second back pressure space 142" is used to encompass a concept of forming a pressure slightly lower than the discharge pressure, for example, a pressure similar to the discharge pressure in the second back pressure space, even if the description is not made separately.

When the roller 134 rotates, the rear end portion of each vane 135 is selectively exposed to the first back pressure space 141 or the second back pressure space 142. The present invention has an effect of adjusting the pressure applied to the rear end portion of each vane 135 by selectively exposing the rear end portion of each vane 135 to the first back pressure space 141 or the second back pressure space 142. If the pressure acting on the rear end portion of the vane 135 is adjusted, the friction loss formed between the front end portion of the vane 135 and the inner circumferential surface of the cylinder 133 can be reduced.

Fig. 4 is a sectional view taken along line iv-iv of fig. 3. Fig. 5 is a sectional view taken along line v-v of fig. 3. Fig. 6 is a perspective view showing a main part of the compressing unit cut. Fig. 4 to 6 are views showing an internal state of the compression unit, and show a structural relationship between each vane 135 and each back pressure space 141 and 142.

The roller 134 is located at the center portion of the cylinder 133. The outer circumferential surface of the roller 134 forms a contact point P (or contact line) with the inner circumferential surface of the cylinder 133. The roller 134 is coupled with the rotation shaft 123. As the rotation shaft 123 rotates, the roller 134 may rotate in a state of sharing a contact point with the inner circumferential surface of the cylinder 133. As described above, when the roller 134 rotates, the vanes 135 protruding from the roller 134 can move in contact with the inner circumferential surface of the cylinder tube 133.

As illustrated in fig. 3, a first back pressure space 141 and a second back pressure space 142 are formed at a lower end of the main bearing 131 and an upper end of the sub-bearing 132, respectively.

The first back pressure space 141 and the second back pressure space 142 may be formed along an arc of a predetermined length, and a rear end of each vane 135 is exposed to the first back pressure space 141 or the second back pressure space 142 as the roller 134 rotates. Accordingly, each back pressure chamber 137 connected to the rear end of each vane 135 may receive the pressure formed at the first back pressure space 141 and the second back pressure space 142.

The positions and sizes of the first and second back pressure spaces 141 and 142 may be described by the lengths of circular arcs on the circumferences corresponding to the long and/or short radii, the differences of the long and short radii, and the heights in the axial direction. Here, the major radius and the minor radius of the circular arc may be measured with reference to the center O of the rotation shaft 123.

In fig. 4 and 5, when comparing the arc of the first back pressure space 141 and the arc of the second back pressure space 142, the arc of the first back pressure space 141 is longer than the arc of the second back pressure space 142.

In addition, the first outer wall surface 141a forming the long radius of the first back pressure space 141 and the second outer wall surface 142a forming the long radius of the second back pressure space 142 have substantially the same radius. In contrast to this, the first inner wall surface 141b forming the short radius of the first back pressure space 141 has a radius larger than the second inner wall surface 142b forming the short radius of the second back pressure space 142. Therefore, when the difference between the long radius and the short radius is compared, the difference between the first back pressure space 141 is smaller than the difference between the second back pressure spaces 142.

Therefore, a kind of relief portion is formed between a bearing surface (i.e., an inner circumferential surface of the shaft hole) radially supporting the rotary shaft 123 and the first inner wall surface 141b forming the short radius of the first back pressure space 141. In contrast, no relief portion is formed between the bearing surface and the second inner wall surface 142b forming the short radius of the second back pressure space 142, or even if a relief portion is formed, the relief rate is lower than that of the first back pressure space 141. Therefore, the first back pressure space 141 forms an intermediate pressure back pressure space, and the second back pressure space 142 forms a discharge pressure back pressure space.

On the other hand, the axial height can be compared in fig. 3, and the axial heights of the first back pressure space 141 and the second back pressure space 142 are substantially the same.

The first back pressure space 141 may be formed at a position spaced apart from the outer circumferential surface of the rotating shaft 123 by a predetermined distance. The first back pressure space 141 may be formed in a shape in which a groove formed from the bottom surface of the main bearing 131 toward the upper portion extends along a predetermined arc or a predetermined radius. The first back pressure space 141 is formed at a position outside the outer peripheral surface of the rotation shaft 123 and along an arc having a predetermined length.

As described previously, an intermediate pressure may be formed in the first back pressure space 141. The first back pressure space 141 is formed at a position spaced apart from the outer circumferential surface of the rotary shaft 123, that is, the inner circumferential surfaces of the main bearing 131 and the sub bearing 132 forming the shaft hole by a predetermined distance, and the inner circumferential surface of the main bearing 131 and the inner circumferential surface of the sub bearing 132 block the communication between the first back pressure space 141 and the second oil flow path 152.

The high-pressure oil rising along the first oil flow path 151 moves along the second oil flow path 152 formed in the radial direction of the rotation shaft 123. The high-pressure oil moving along the second oil flow path 152 may move toward the first back pressure space 141 through a gap between the lower surface of the main bearing 131 and the upper surface of the roller 134. Similarly, the high-pressure oil moving along the second oil flow path 152 moves to the first back pressure space 141 through a gap between the upper surface of the sub-bearing 132 and the lower surface of the roller 134.

Since the gap between the main bearing 131 and the roller 134 or the gap between the sub bearing 132 and the roller 134 forms the relief portion, the pressure of the oil moving to the first back pressure space 141 through the gaps is reduced. This is because the flow rate of oil moving through the gap is limited. Thereby, an intermediate pressure, which is a pressure lower than the discharge pressure of the oil, is formed in the first back pressure space 141.

The second back pressure space 142 directly communicates with the second oil flow path 152. As a result, the oil moves to the second back pressure space 142 along the second oil flow path 152, and the discharge pressure, which is the pressure of the second oil flow path 152, acts on the second back pressure space 142.

The second back pressure space 142 is formed on a lower surface of the main bearing 131 and an upper surface of the sub-bearing 132, respectively. The second back pressure space 142 is formed in a groove shape formed from a lower surface toward an upper portion of the main bearing 131. The second back pressure space 142 is formed in a groove shape formed from the upper surface of the sub-bearing 132 toward the lower portion. The second back pressure space 142 is disposed to face the first back pressure space 141 at the outer circumference of the rotation shaft 123. The second back pressure space 142 is formed along an arc of a prescribed length. The second back pressure space 142 directly communicates with the second oil flow path 152, and can generate the same oil pressure as the discharge pressure.

The first back pressure space 141 and the second back pressure space 142 are formed on the lower surface of the main bearing 131 and the upper surface of the sub-bearing 132, respectively, at positions overlapping the back pressure chambers 137 in which the rear end portions of the respective blades 135 are located, and the pressure formed in the first back pressure space 141 or the second back pressure space 142 acts on the respective back pressure chambers 137. Since the rear end portion of each vane 135 is located in the back pressure chamber 137, each vane 135 protrudes from the roller 134 and comes into contact with the inner peripheral surface of the cylinder 133 due to the pressure formed in the back pressure chamber 137.

For example, when the rotary shaft 123 rotates counterclockwise, the roller 134 rotates counterclockwise with one side thereof contacting the inner circumferential surface of the cylinder 133, and the blades 135 provided inside the roller 134 move while protruding and contacting the inner circumferential surface of the cylinder 133.

As shown in fig. 4 and 5, the first back pressure space 141 and the second back pressure space 142 may be formed in regions that can be divided at a predetermined angle. The first back pressure space 141 may be formed in a region between a suction stroke in which the refrigerant is sucked into the compression space and a rear half of a compression stroke before the start of discharge, and may be formed to apply a pressure formed in the first back pressure space 141 to a rear end portion of the vane 135. Hereinafter, a region where the first back pressure space 141 is formed will be described in detail, and the first back pressure space 141 may be formed in a region from a position before a position where the refrigerant starts to flow into the compression space V through the suction port 111 to a position where the roller 134 rotates and the vane 135 moves to almost end a compression stroke of the refrigerant. This is to reduce the contact force between the front end of the vane 135 and the inner circumferential surface of the cylinder 133 by relatively reducing the pressure acting on the rear end of the vane 135 when the front end of the vane 135 is exposed to the compression space and the force applied to the rear end of the vane 135 is relatively small.

That is, the first back pressure space 141 is formed at a position where an intermediate pressure can be applied to the rear end portions of the respective vanes 135 that move along the inner circumferential surface of the cylinder 133 as the roller 134 rotates, from the suction stroke to the end of the compression stroke. This can reduce mechanical loss generated between the tip of the vane 135 and the inner circumferential surface of the cylinder 133.

Next, the area where the first back pressure space 141 is formed is specifically determined, and when the first back pressure space 141 takes a line connecting the center O of the rotary shaft 123 and the contact point P, which is a portion where the roller 134 and the inner peripheral surface of the cylinder 133 contact, as a reference line, the first back pressure space 141 is formed in the area where the intermediate pressure forming angle α is formed. There is one side boundary and the other side boundary in the intermediate press forming angle α.

First, one side boundary of the intermediate press forming angle α will be readily understood with reference to fig. 4. As shown in fig. 4, when the leading end of vane 135 is located at the start point of suction port 111, vane 135 located at the rightmost side forms the one-side boundary at the position where the trailing end of vane 135 is located.

In addition, the other side boundary of the intermediate pressure forming angle α will be easily understood with reference to fig. 7B described later. As in the leftmost vane 135 in fig. 7B, when the leading end portion of the vane is located at a position where compression of the refrigerant accommodated in the compression space V is almost completed, the other-side boundary is formed at a position where the trailing end portion of the vane 135 is located.

According to this structure, the force generated by the front end of the vane 135 being located in the compression space V reduces the pressure applied to the rear end of the vane 135 in a relatively small area. This reduces the contact loss formed between the tip end of the vane 135 and the inner circumferential surface of the cylinder 133.

For example, the first back pressure space 141 for forming the intermediate pressure may be formed in a region from a position where the suction stroke starts to a position before the discharge start as the end of the compression stroke, that is, a region from approximately 60 ° in the clockwise direction from the reference line to approximately 160 ° in the counterclockwise direction from the reference line. In this case, the intermediate pressure forming angle α is approximately around 220 °.

The second back pressure space 142 is formed at a lower surface of the main bearing 131 and an upper surface of the sub bearing 132, respectively, and is formed at a position where the first back pressure space 141 is not formed. The second back-pressure space 142 is formed so as to communicate with the second oil flow path 152, and the rear end portion of each vane 135 communicates with the second back-pressure space 142 and can receive the action of the discharge pressure as the pressure of the high-pressure oil.

The second back pressure space 142 is formed in a region from the latter half of the compression stroke in which the refrigerant is compressed to a portion where the compressed refrigerant is discharged. Describing the region where the second back pressure space 142 is formed, when a reference line connecting a contact point, which is a portion where the inner circumferential surface of the cylinder tube 133 contacts the roller 134, and the rotation shaft 123 is set to 0 °, the second back pressure space 142 may be formed in a region between 160 ° and 300 ° substantially in the counterclockwise direction.

That is, the region where the second back pressure space 142 and the rear end portion of each vane 135 communicate may be a position between a position at which the rear end portion of the vane 135 is located at approximately 160 ° when compression of refrigerant accommodated in the compression space is almost finished and a position at which the rear end portion of the vane 135 is located at approximately 300 ° when the front end portion of the vane 135 is located at the suction start point.

That is, the pressure of the high-pressure oil moving through the second oil flow path 152 acts on the second back pressure space 142, and the discharge pressure forming angle β may have an angle of approximately 160 ° to 300 ° in the counterclockwise direction, that is, 140 °.

Next, the operation of rotary compressor 100 will be described.

Fig. 7A to 7D are operation state diagrams of the rotary compressor 100 illustrating a process in which the refrigerant is compressed as the roller 134 rotates.

If the roller 134 rotates, the blades 135a, 135b also move with the roller 134. When the back pressure chambers 137a and 137b are exposed to the back pressure spaces 141 and 142 during the movement of the vane 135, the same pressure as that of the back pressure spaces 141 and 142 acts on the vanes 135a and 135 b. Thereby, the vane 135 moves in close contact with the inner circumferential surface of the cylinder 133.

First, referring to fig. 7A, suction port 111 is located between leading blade 135a and trailing blade 135 b. Therefore, the refrigerant flows into the volume change space between the leading vane 135a and the trailing vane 135 b.

The two vanes 135a, 135b are pressurized by back pressure formed in the back pressure chambers 137a, 137b, respectively. The two back pressure chambers 137a and 137b are exposed to the first back pressure space 141. Therefore, an intermediate pressure is formed in the two back pressure chambers 137a and 137b, and the two vanes 135a and 135b are pressed to the intermediate pressure and brought into close contact with the inner peripheral surface of the cylinder 133.

Next, referring to fig. 7B, the refrigerant between the two vanes 135a, 135B is gradually compressed due to the decrease in the volume fluctuation space. If the pressure of the refrigerant increases, the vanes 135a, 135b may be pushed toward the back pressure chambers 137a, 137b, and thus, leakage of the refrigerant may occur. Therefore, in order to prevent leakage of the refrigerant, it is necessary to form a stronger back pressure in the back pressure chambers 137a and 137 b.

The back pressure chamber 137a of the leading vane 135a is passing through the intermediate pressure forming angle α into the discharge pressure forming angle β. Therefore, the back pressure formed in the back pressure chamber 137a of the preceding vane 135a is in the process of increasing from the intermediate pressure to the discharge pressure.

The back pressure chamber 137b of the trailing vane 135b is still at the intermediate pressure forming angle a. Therefore, the back pressure chamber 137b of the trailing vane 135b maintains a back pressure corresponding to the intermediate pressure.

Referring to fig. 7C, as the volume-varying space becomes smaller, the refrigerant between the two vanes is compressed. The back pressure chamber 137a of the leading vane 135a is located within the discharge pressure forming angle β, and a back pressure corresponding to the discharge pressure is formed in the back pressure chamber 137 a.

At this time, the preceding vane 135a can be moved backward by the shape of the inner peripheral surface of the cylinder while moving from the position of fig. 7B to the position of fig. 7C. This increases the pressure in the back pressure chamber 137a formed on the rear side of the vane 135 a.

However, as the second back pressure space 142 is formed as an open space to directly communicate with the second oil flow path 152, the oil in the back pressure chamber 137a located on the rear side of the vane 135a is reversed to the first oil flow path 151 through the second back pressure space 142 and the second oil flow path 152 according to the pressure difference. Accordingly, the pressure in the back pressure chamber 137a formed on the rear side of the vane 135a does not rise to or above the discharge pressure, and the discharge pressure is maintained or slightly lowered. This will be described again later with reference to fig. 8.

On the other hand, the back pressure chamber 137b of the trailing vane 135b is located within the intermediate pressure forming angle α, and a back pressure corresponding to the intermediate pressure is formed in the back pressure chamber 137 b.

As the leading vane 135a passes through the first discharge port 112a, the refrigerant compressed to a high pressure starts to be discharged through the first discharge port 112 a.

Finally, referring to fig. 7D, as the volume fluctuation space becomes smaller, the refrigerant compression between the two vanes 135a and 135b is almost completed. As the leading vane 135a passes through the second discharge port 112b, the refrigerant compressed to a high pressure starts to be discharged not only through the first discharge port 112a but also through the second discharge port 112 b.

The back pressure chamber 137a of the leading vane 135a is passing through the discharge pressure forming angle β into the intermediate pressure forming angle α. Therefore, the back pressure formed in the back pressure chamber 137a of the preceding vane 135a is in a process of decreasing from the discharge pressure to the intermediate pressure.

The back pressure chamber 137b of the trailing vane 135b is located within the discharge pressure forming angle β, and a back pressure corresponding to the discharge pressure is formed in the back pressure chamber 137 b.

By repeating the procedure described with reference to fig. 7A to 7D, the refrigerant is sucked, compressed, and discharged.

Fig. 8 is a graph showing the magnitude of pressure formed in the back pressure chamber 137 with the rotation angle of the roller 134 when a line connecting the contact point P between the cylinder 133 and the roller 134 and the center of the rotation shaft 123 is set to the reference position of 0 °.

As described above, since the first back pressure space 141 does not directly communicate with the second oil flow path 152, the pressure of the oil reduced by passing through the clearance between the main bearing 131 and the sub-bearing 132 acts. Thereby, the intermediate pressure Pm lower than the discharge pressure Pd, which is the pressure of the oil supplied from the oil feeder 136, is formed. When a line connecting the contact point and the center O of the rotation shaft 123 is taken as a reference line 0 °, the first back pressure space 141 may be formed in a region from-60 ° to +160 °.

Therefore, when the back pressure chamber passes through a region between-60 ° and +160 ° communicating with the first back pressure space, the intermediate pressure Pm of the first back pressure space is formed in the back pressure chamber.

Since the second back pressure space 142 communicates with the second oil flow path 152 formed to penetrate the rotation shaft 123, the discharge pressure Pd, which is the pressure of the oil supplied from the oil feeder 136, is formed. Since the second back pressure space 142 and the second oil flow path 152 communicate with each other, the magnitude of the pressure formed in the second back pressure space 142 is restricted from being larger than the magnitude of the discharge pressure Pd, which is the pressure of the supplied oil. As shown in fig. 8, the second back pressure space 142 may be formed in an area from 160 ° to 300 °.

Therefore, when the back pressure chamber passes through a region between +160 ° and +300 ° (-60 °) that communicates with the second back pressure space, the discharge pressure Pd of the second back pressure space is formed in the back pressure chamber.

If the discharge pressure Pd, which is the pressure of the oil, is constantly applied to the rear end portion of the vane 135, a large friction loss occurs between the front end portion of the vane 135 and the inner circumferential surface of the cylinder 133 in a region where the pressure formed at the front end portion of the vane 135 exposed to the compression space V is relatively low, and the efficiency of the compressor is lowered. Thus, in the present invention, the intermediate pressure Pm in the first back pressure space 141 is formed in the back pressure chamber 137 in a region from a portion where the intake stroke starts to a portion before the discharge starts, which is the end of the compression stroke.

As shown in fig. 8, the intermediate pressure Pm is formed at the rear end of the vane 135 located in the first back-pressure space 141, and a pressure lower than the discharge pressure Pd, which is a pressure of high-pressure oil, is formed at the rear end of the vane 135 located in the second back-pressure space 142. In particular, as the second back pressure space 142 and the second oil flow path 152 directly communicate with each other, the pressure of the back pressure chamber 137 communicating with the second back pressure space 142 can be prevented from increasing to the discharge pressure Pd or more. Therefore, the intermediate pressure Pm lower than the discharge pressure Pd is formed in the first back pressure space 141, and the discharge pressure Pd or a pressure lower than the discharge pressure Pd is formed in the second back pressure space 142 while reducing the mechanical loss between the cylinder 133 and the vane 135. If a pressure higher than the discharge pressure Pd is formed in the second back pressure space 142, a large mechanical friction loss occurs between the cylinder 133 and the vane 135.

Fig. 9A is a sectional view illustrating another embodiment of the rotary compressor 100 according to the present invention.

As explained above, the first back pressure space 141 and the second back pressure space 142 are formed in the main bearing 131 and the sub-bearing 132, respectively, and the pressure acting on the rear end portion of each blade 135 changes with the rotation of the roller 134. The pressure formed in the first back pressure space 141 and the pressure formed in the second back pressure space 142 are formed at the rear end of each vane 135, and the description of the same portions as those described above is omitted.

The rotary compressor 100 of the present embodiment may be formed such that the first back pressure space 141 communicates with the compression space V. The first back pressure space 141 and the compression space V may communicate through the compression chamber communication flow paths 161, 162. A first compression chamber communication passage 161 for communicating one side of the first back pressure space 141 with the compression space V of the cylinder 133 may be formed inside the main bearing 131. Similarly, a second compression chamber communication passage 162 that communicates one side of the first back pressure space 141 with the compression space V of the cylinder tube 133 may be formed inside the sub-bearing 132.

The first and second compression chamber communication passages 161 and 162 function to reduce the magnitude of the intermediate pressure formed in the first back pressure space 141. The shapes of the first compression chamber communication passage 161 and the second compression chamber communication passage 162 are not limited, and may be formed to extend from one side surface of the first back pressure space 141 in the radial direction by a length corresponding to the overlap with the compression space V.

An intermediate pressure may be formed in the first back pressure space 141 by the oil moving through the gap between the main bearing 131 and the sub-bearing 132. The first back pressure space 141 is formed to communicate with the compression space V so that the magnitude of the intermediate pressure formed at the first back pressure space 141 can be further made lower. In this case, the friction loss formed between the tip end of the vane 135 and the inner circumferential surface of the cylinder 133 can be further reduced.

Fig. 9B is an enlarged view of a state where the first back pressure space 141 communicates with the compression space V.

The compression chamber communication passages 161 and 162 communicate the first back pressure space 141 and the compression space V. The high-pressure oil moving along the first oil flow path 151 moves in the radial direction of the rotation shaft 123 along the second oil flow path 152, and moves to the first back pressure space 141 through the gap between the main bearing 131 and the roller 134. At this time, the pressure of the high-pressure oil is reduced to the pressure of the intermediate pressure as it moves to the first back pressure space 141, which is the same as that described above.

The first back pressure space 141 and the compression space V may communicate with each other through the compression chamber communication flow paths 161, 162. Here, the position of the compression space communicating with the first back pressure space 141 may be formed at any position of the compression space from the suction stroke to the end of the compression stroke so that the pressure formed in the first back pressure space 141 can be lowered. However, since the vane 135 protrudes due to the pressure formed in the first back pressure space 141, the tip end portion of the vane 135 and the inner peripheral surface of the cylinder 133 contact each other, and the compression chamber communication passages 161 and 162 preferably communicate with the compression space V from the portion where compression starts, so that the pressure formed in the first back pressure space 141 is limited to a predetermined level or less.

If the pressure of the refrigerant contained in the compression space V is lower than the pressure of the oil contained in the first back pressure space 141, a part of the oil contained in the first back pressure space 141 moves to the compression space V, and the pressure formed in the first back pressure space 141 becomes low.

Fig. 10 is a view showing a state where the first back pressure space 141 is communicated with the compression space V through the compression chamber communication passage 160. The first back pressure space 141 may communicate with the compression space through the compression chamber communication flow path 160, and thus, a pressure formed at the first back pressure space 141 may be smaller than a pressure when not communicating with the compression space V.

Fig. 11 is a graph showing a relationship between the pressures in the back pressure spaces 141 and 142 and the pressure formed in the compression space V according to the rotation angle.

In the graph, the rotation angle is shown with reference to an imaginary straight line connecting the contact point P where the roller 134 and the inner peripheral surface of the cylinder 133 contact each other and the center O of the rotation shaft 123. The pressures formed in the first back pressure space 141, the second back pressure space 142, and the compression space V may be set to any value according to the user's reference.

If the first back pressure space 141 communicates with the compression space V, the pressure formed at the compression space V is lower than the pressure formed at the first back pressure space 141, and thus the pressure formed at the first back pressure space 141 is reduced. The pressure formed in the first back pressure space 141 may have a magnitude lower than the discharge pressure Pd, which is the pressure of the oil supplied through the oil feeder 136, and the magnitude may be further reduced by communicating with the compression space V.

The first back pressure space 141 is formed in a region ranging from-60 ° to 160 ° which is a range from each suction stroke to the end of the compression stroke, respectively, at the lower surface of the main bearing 131 and the upper surface of the sub-bearing 132. The second back pressure space 142 may be formed in a range area of 160 ° to 300 °. If the first back pressure space 141 communicates with the compression space V, the pressure formed at the first back pressure space 141 may be reduced in the arrow direction to have a pressure similar to that of the compression space V, whereby the force acting on the rear end portion of the vane 135 may be reduced. Accordingly, mechanical friction loss generated between the vane 135 located in the first back pressure space 141 and the inner circumferential surface of the cylinder 133 can be reduced.

Fig. 12A shows a state where the resonator space portion 171 of the cylinder tube 133 and the first back pressure space 141 are communicated with each other, and fig. 12B is an enlarged view of a state where the first back pressure space 141 and the resonator space portion 171 are communicated with each other through the resonator communication flow path 170. Fig. 13 is a graph showing the magnitude of pressure when the first back pressure space 141 and the resonator space portion 171 communicate with each other through the resonator communication flow path 170 and when they are not communicated with each other.

An intermediate pressure smaller than the discharge pressure is formed in the first back pressure space 141. However, the intermediate pressure formed in the first back pressure space 141 generates a pressure pulsation phenomenon in which the magnitude of the pressure changes within a predetermined range. As a result, the magnitude of the pressure acting on the rear end of the vane 135 changes, and the magnitude of the contact force formed between the inner circumferential surface of the cylinder 133 and the front end of the vane 135 also changes.

The rotary compressor 100 according to the present invention is provided with the resonator space portion 171, the resonator space portion 171 is formed at a position spaced apart from (or spaced apart from) the inner space (compression space, V) formed at the central portion of the cylinder tube 133, and the first back pressure space 141 is formed to communicate with the resonator space portion 171 through the resonator communication flow path 170.

The resonator space portion 171 has a predetermined space and communicates with the first back pressure space 141, thereby reducing a pressure pulsation phenomenon in which the magnitude of the intermediate pressure formed in the first back pressure space 141 changes. This enables a predetermined back pressure to act on the rear end of the vane 135.

The solid line of fig. 13 indicates the pressure formed at the first back pressure space 141 when the first back pressure space 141 and the resonator space part 171 are not communicated with each other, and the pressure formed at the first back pressure space 141 is subjected to a pressure pulsation phenomenon that varies in a range of Pmax to Pmin according to the rotation angle.

The broken line (or broken line) in fig. 13 indicates the magnitude of pressure formed in the first back pressure space 141 when the resonator space portion 171 and the first back pressure space 141 communicate with each other. When the first back pressure space 141 and the resonator space 171 communicate with each other, an intermediate pressure Pm of a predetermined magnitude is formed in the first back pressure space 141.

Referring to fig. 12B, the resonator space 171 formed in the cylinder 133 and the first back pressure space 141 communicate with each other through the resonator communication flow path 170. The resonator communication flow path 170 extends from the first back pressure space 141 side to a position of the cylinder 133 where the resonator space 171 is formed. Since the pressure formed in the resonator space 171 is lower than the pressure formed in the first back pressure space 141, the magnitude of the intermediate pressure formed in the first back pressure space 141 can be further reduced, and thus the mechanical loss formed between the vane 135 and the inner circumferential surface of the cylinder 133 can be reduced.

The high-pressure oil that moves along the first oil flow path 151 moves in the radial direction (radial direction) of the rotating shaft 123 along the second oil flow path 152, and flows into the first back pressure space 141 through the gap between the main bearing 131 and the roller 134 with the pressure reduced. If the first back pressure space 141 communicates with the resonator space 171, the magnitude of the intermediate pressure formed in the first back pressure space 141 is reduced, and the pressure pulsation phenomenon is also reduced. In addition, in fig. 12B, although the resonator communication flow path 170 is not in communication with the compression space V, the resonator communication flow path 170 may be in communication with the compression space V.

Fig. 14 is a diagram showing a state in which the first back pressure space 141 is divided into two space portions, and fig. 15 is a graph showing pressure changes in the first back pressure space 141 and the second back pressure space 142 in the compressor having the configuration shown in fig. 14.

The first back pressure space 141 may be formed of two or more space portions formed along an arc of a set length. For example, as shown in fig. 14, the first back pressure space 141 may be divided into two regions.

The first back pressure space 141 is intended to reduce the magnitude of back pressure acting on the rear end portion of the vane 135 from the intake stroke to the end of the compression stroke. However, as shown in fig. 14, if the first back pressure space 141 is divided into two spaces, the pressure formed in the first back pressure space 141 can be changed in stages, and the sum of the total magnitudes of the back pressures acting on the rear ends of the vanes 135 is smaller than that in the case where the two spaces are formed integrally, whereby the mechanical friction loss generated between the vanes 135 and the inner circumferential surface of the cylinder 133 can be reduced.

In particular, in a region between-60 ° at the beginning of the suction stroke and 120 ° at which the compression stroke is performed, a lower pressure is formed than when the first back pressure space 141 is integrally formed, and thus the mechanical friction loss generated between the vane 135 and the inner circumferential surface of the cylinder 133 is reduced. As shown in fig. 15, it can be confirmed that the magnitude of the pressure formed in the region between-60 ° and 120 ° of the rotation angle is lower than that formed in the region between 120 ° and 160 °.

On the other hand, as described above, in order to obtain the same level of freezing capacity when a low-pressure refrigerant such as R-32 is used as when a refrigerant such as R-134a or R-410a is used, it is necessary to increase the number of blades or the volume (or number) of the cylinder. However, if the number of blades or the volume of the cylinder is increased, the mechanical friction loss between the cylinder and the blades is increased accordingly. This is also the reason why a low pressure refrigerant such as R-32 cannot be used in the rotary compressor. However, as in the above-described embodiment, if the pressure of the back pressure chamber can be appropriately adjusted, even if the number of the vanes or the volume of the cylinder is increased, the increase in the mechanical friction loss between the vanes and the cylinder can be effectively suppressed, and even if a low-pressure refrigerant such as R-32 is used, the same level of freezing capacity as that when a refrigerant such as R-134a or R-410a is used can be obtained.

The above description is only an embodiment of the rotary compressor 100 for implementing the present invention, and the present invention is not limited to the above-mentioned embodiment, and as described in the claims, various modifications and implementation ranges that can be made by those skilled in the art are within the technical idea of the present invention without departing from the scope of the gist of the present invention.

Fig. 16 is a sectional view showing a deformed structure of the compression space V.

The compression space of the rotary compressor described hereinbefore has a cross section similar to an elliptical shape. The ellipse-like shape is a shape formed by curved surfaces that are symmetrical left and right and asymmetrical up and down (or symmetrical up and down and asymmetrical left and right) when the compression space V is divided into four quadrants on the basis of the center of the compression space V.

In contrast, the compression space of the rotary compressor shown in fig. 16 has a cross section of a perfect circle shape. The perfect circle shape is a shape in which the inner circumferential surfaces of the cylinder tubes 133 are all present at the same distance from the center of the compression space V. The right circular shape is a shape formed by curved surfaces that are vertically symmetrical and horizontally symmetrical when the compression space is divided into four quadrants.

Fig. 17 is a sectional view showing another modified structure of the compression space V.

The compression space of the rotary compressor shown in fig. 17 has a cross section of a mixed elliptical shape. The mixed elliptical shape is a shape formed by curved surfaces which are asymmetric in the left-right direction and asymmetric in the up-down direction when the compression space V is divided into four quadrants on the basis of the center of the compression space V. The curvatures of the curved surfaces located in each of the four quadrants are different from each other.

Industrial applicability

The present invention is applicable to industrial fields requiring compressed refrigerants, and to industrial fields for implementing rotary compressors.

Claims (3)

1. A rotary compressor, comprising:

a driving motor disposed inside the housing to generate a rotational force;

a rotating shaft which transmits a rotational force generated by the driving motor and has an oil flow path formed at a center portion thereof in an axial direction;

a main bearing and a sub-bearing fixed to the housing and provided along the rotation axis;

a cylinder tube fixedly provided between the main bearing and the sub bearing and accommodating a refrigerant at a central portion thereof;

a roller located at a center portion of the cylinder, forming a compression space for compressing a refrigerant between the roller and an inner circumferential surface of the cylinder by rotating together with the rotating shaft, and having two or more blade grooves formed along a circumferential direction; and

two or more vanes inserted into the two or more vane grooves, respectively, protruding from the vane grooves by a pressure acting on each back pressure chamber, and contacting an inner circumferential surface of the cylinder tube, thereby dividing the compression space into a suction chamber and a compression chamber, respectively;

a back pressure space is formed in a bottom surface of the main bearing or a top surface of the sub bearing so that oil moving along the oil flow path is transferred to each back pressure chamber, the back pressure chambers are formed in inner end portions of two or more blade grooves of the roller so that rear surfaces of the blades are supported on an inner circumferential surface side of the cylinder tube,

the back pressure space includes:

a first back pressure space that forms an intermediate pressure between a suction pressure sucked into the compression space and a discharge pressure discharged from the compression space; and

a second back pressure space spaced apart from the first back pressure space and forming a pressure higher than that of the first back pressure space;

a resonator space portion separated from the compression space is formed in the cylinder tube, a resonator communication flow path for communicating the first back pressure space and the resonator space portion is formed in the main bearing or the sub-bearing in which the back pressure space is formed,

the resonator communication flow path is formed to penetrate through the main bearing or the sub-bearing in which the resonator space portion is formed so as to be separated from the compression space.

2. The rotary compressor of claim 1,

the resonator space portion is formed to be wider than the first back pressure space.

3. The rotary compressor of claim 1,

the oil flow path includes:

a first oil flow path that moves high-pressure oil in a direction in which the rotary shaft extends along a center portion of the rotary shaft; and

a second oil flow passage communicating with the first oil flow passage, penetrating the rotary shaft, and formed in a direction intersecting the first oil flow passage;

the first back pressure space is formed at a position spaced apart from the shaft hole of the main bearing or the shaft hole of the sub bearing by a predetermined distance so as not to face the second oil flow path;

the second back pressure space is formed at a corner of the main bearing forming the shaft hole or a corner of the sub bearing forming the shaft hole to face the second oil flow path.

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