KR102070286B1 - Motor operated compressor - Google Patents

Abstract

An objective of the present invention is to provide an electrically-driven compressor capable of extending the service life of a main bearing. According to the present invention, the electrically-driven compressor comprises: a frame arranged on one side of a motor chamber; a drive motor accommodated in the motor chamber on one side of the frame; a first and a second scroll forming a compression chamber; a rotary shaft to transfer torque of the drive motor to the second scroll, wherein one end thereof is coupled to a rotor of the drive motor and the other end thereof is eccentrically coupled to the second scroll; a balance weight having an opposing surface facing the rear surface of the second scroll to be coupled to the rotary shaft; a sealing member arranged between the rear surface of the second scroll and the opposing surface of the balance weight to form a back pressure space between the rear surface of the second scroll and the opposing surface of the balance weight; and a back pressure flow path formed by penetrating the second scroll to connect a gap between the compression chamber and the back pressure space.

Description

Electric Compressor {MOTOR OPERATED COMPRESSOR}

The present invention relates to a scroll-type electric compressor.

In general, compressors that play a role of compressing a refrigerant in a vehicle air conditioning system have been developed in various forms, and in recent years, the development of electric compressors that are electrically driven by using motors has been actively performed according to the trend of increasing the length of automobile parts.

The motor-driven compressor mainly employs a scroll compression method suitable for high compression ratio operation. Such a scroll-type electric compressor (hereinafter, abbreviated as “electric compressor”) is provided with an electric motor made of a rotating motor inside the sealed casing, and a compression part made of a fixed scroll and a rotating scroll is installed on one side of the electric motor. And the compression unit is connected to the rotating shaft is configured to transmit the rotational force of the transmission unit to the compression unit.

As disclosed in Japanese Patent Application Laid-Open No. 2014-125957, a conventional electric compressor includes a suction space for accommodating refrigerant and oil sucked in a motor chamber, and refrigerant and oil discharged from the compression chamber. And a discharge space constituting a kind of oil separation space, and a back pressure space for accommodating mist oil (hereinafter, gas oil) separated from the refrigerant in the discharge space and pressurizing the turning scroll toward the fixed scroll by the pressure of the gas oil. It is. The suction space is formed in the main housing constituting the casing, the discharge space is formed in the rear housing constituting the casing together with the main housing, and the back pressure space is formed in the main frame which is coupled to the main housing to support the turning scroll in the axial direction.

In the conventional electric compressor as described above, a back pressure flow path is formed in the fixed scroll (or / and the main frame) so that the gas oil is supplied from the discharge space to the back pressure space. At this time, a pressure reducing device is installed in the back pressure passage to reduce the pressure of the gas oil supplied to the back pressure space to adjust the pressure in the back pressure space.

However, in the conventional electric compressor as described above, as the back pressure space communicates with the discharge space through the back pressure passage, the back pressure of the back pressure space is affected by the pressure of the discharge space rather than the pressure of the compression chamber. Accordingly, even if the pressure in the compression chamber changes during operation, the back pressure generally forms a constant pressure. When the back pressure is larger than the required back pressure, both scrolls are in close contact with each other and the friction loss increases while the back pressure is increased. If it is less than the required back pressure, compression may occur due to excessive space between both scrolls.

In addition, in the conventional electric compressor, as the back pressure space is formed in the back pressure space in which the balance weight is accommodated, the volume of the back pressure space increases, which makes it difficult to quickly secure the back pressure at the beginning of operation.

In addition, in the conventional electric compressor, the main bearing is provided in the back pressure space, which may reduce the life of the main bearing while excessive load is applied to the main bearing by the pressure in the back pressure space.

In addition, in the conventional electric compressor, the sealing member forming the back pressure space is inserted into the turning scroll or the main frame, which may be difficult to secure the necessary sealing force when the pressure in the back pressure space is excessively increased. In particular, even in the case of a high-pressure refrigerant in which the back pressure rises to 60 to 70 bar, such as a CO ₂ refrigerant, the back pressure space may not be effectively sealed, and the scroll scroll behavior may become unstable.

Japanese Patent Application Laid-Open No. 2014-125957 (published Jul. 7, 2014).

It is an object of the present invention to provide an electric compressor capable of securing and maintaining a required back pressure in a back pressure of a back pressure space.

Furthermore, it is an object of the present invention to provide an electric compressor capable of interlocking a back pressure of a back pressure space with a pressure of a compression chamber.

Another object of the present invention is to provide an electric compressor which enables the interior of the back pressure space to quickly form the required back pressure.

Furthermore, it is an object of the present invention to provide an electric compressor that can smoothly support the turning scroll while reducing the volume of the back pressure space.

In addition, another object of the present invention is to provide an electric compressor that can increase the life of the main bearing by reducing the load on the main bearing accommodated in the back pressure space.

Another object of the present invention is to provide an electric compressor that can simplify the structure of the pressure reducing device and reduce the manufacturing cost by reducing the number of parts constituting the pressure reducing device.

In order to achieve the object of the present invention, the compression chamber formed between the first scroll and the second scroll; A back pressure space provided to support the second scroll in a first scroll direction; And a back pressure hole provided in the second scroll and guiding a part of the refrigerant compressed in the compression chamber to the back pressure space, wherein the back pressure space includes a balance weight coupled to the rotating shaft together with the second scroll and the second back pressure space. An electric compressor may be provided, which is formed between the scrolls.

Here, a sealing groove is formed in the second scroll such that a sealing member for sliding the back pressure space is slidably inserted into the sealing scroll, and the sealing groove communicates with the compression chamber a portion of the refrigerant compressed in the compression chamber. The pressing hole may be formed to guide to the opposite side of the sealing surface.

The pressure hole may be in communication with the back pressure hole.

In addition, in order to achieve the object of the present invention, the casing is provided with a motor chamber; A frame provided at one side of the motor chamber; A drive motor accommodated in the motor chamber at one side of the frame; A first scroll supported on the other side of the frame and having a spiral wrap formed thereon; A second scroll having a spiral wrap to be engaged with the wrap of the first scroll and forming a compression chamber between the wraps while being swiveled by a rotational force of the driving motor; One end is coupled to the rotor of the drive motor, the other end is eccentrically coupled to the second scroll, the rotating shaft for transmitting the rotational force of the drive motor to the second scroll; A balance weight provided to face the rear surface of the second scroll and coupled to the rotation shaft; A sealing member provided between the rear surface of the second scroll and the opposing surface of the balance weight to form a back pressure space between the rear surface of the second scroll and the opposing surface of the balance weight; And a back pressure flow passage provided through the second scroll to communicate between the compression chamber and the back pressure space.

Here, the second scroll may be formed with an annular sealing groove so that the sealing member is slidably inserted in the axial direction, the second scroll may be formed through the pressure passage for communicating between the sealing groove and the compression chamber. .

In addition, the pressure flow passage may be formed to be smaller than or equal to the thickness of the wrap.

The pressurized flow path may be in communication with a compression chamber immediately before the compressed refrigerant is discharged or the compression chamber discharged from the compression chamber.

The radial area of the back pressure space may be greater than or equal to the radial area of the compression chamber in which the pressure passage communicates.

The back pressure passage and the pressurized passage may be formed to communicate with each other.

The back pressure passage may have an inner diameter smaller than or equal to that of the pressure passage.

The back pressure passage and the pressurized passage may be formed independently of each other.

The back pressure passage and the pressurized passage may be formed to communicate with the same compression chamber.

Here, the second scroll is formed with a back pressure protrusion protruding annularly toward the balance weight, the back pressure protrusion is formed with a sealing groove for inserting the sealing member to slide in the axial direction, the back pressure flow path is the back pressure stone It may be formed to penetrate inward than the inner peripheral surface of the portion.

Here, the second scroll is formed with a back pressure space groove recessed by a predetermined depth on the surface facing the balance weight, and a sealing groove in which the sealing member is slidably inserted in the axial direction on the outside of the back pressure space groove. The back pressure flow passage may be formed to penetrate the inside of the back pressure space groove.

Here, the balance weight, the eccentric pin portion is fixed to the rotating shaft coupled to the second scroll; An eccentric mass portion extending from the eccentric pin portion, the center of gravity of which is located eccentrically from the center of the rotating shaft; And a back pressure surface portion extending from the eccentric pin portion in the radial direction opposite to the eccentric mass portion to form a back pressure space portion together with the eccentric mass portion.

Here, the frame may be provided with an accommodating space for accommodating the balance weight, and the accommodating space may communicate with the motor compartment.

In addition, a bearing support may be stepped on one side of the accommodation space, and the bearing support may be provided with a ball bearing for supporting the rotating shaft.

Here, the second scroll may be formed with a boss groove to which the rotating shaft is coupled, and a bush bearing may be provided between the inner circumferential surface of the boss groove and the outer circumferential surface of the rotating shaft.

Here, a discharge space is formed in the casing to accommodate the refrigerant and oil discharged from the compression chamber, the discharge space is formed with an oil recovery passage for guiding the refrigerant and oil in the discharge space to the suction side of the compression chamber, The oil return passage may be provided with a pressure reducing member.

In the electric compressor according to the present invention, the pressure in the back pressure space is formed so as to be interlocked with the pressure in the compression chamber, so that the pressure in the back pressure space can be changed according to the pressure change in the compression chamber, thereby maintaining the required back pressure. It is possible to suppress the friction loss that may occur when the pressure is higher than the required back pressure, while suppressing the compression loss that may occur when the pressure is lower than the required back pressure.

In addition, in the motor-driven compressor according to the present invention, as the back pressure space is formed between the second scroll and the balance weight, the volume of the back pressure space is reduced, and through this, the required back pressure can be quickly formed, thereby improving the compressor efficiency. have. In addition, as the back pressure hole communicates with the compression chamber constituting the discharge pressure or the compression chamber immediately before the discharge chamber, the required back pressure can be secured more quickly even if the volume of the back pressure space is reduced. Furthermore, the radial area of the back pressure space is wider than the radial area of the compression chamber communicating with the back pressure space, so that it is possible to stably support the turning scroll.

In addition, in the electric compressor according to the present invention, since the main bearing supporting the rotating shaft is installed outside the back pressure space, the main bearing does not directly receive the load due to the high pressure in the back pressure space, and thus the life of the main bearing. Can be extended.

Further, in the electric compressor according to the present invention, as the sealing member forming the back pressure space is supported in the axial direction by the pressure hole communicated with the compression chamber, the sealing force of the sealing member can be improved. Through this, even when a high pressure refrigerant such as a CO ₂ refrigerant is applied, the back pressure space can be effectively sealed, so that the required back pressure can be smoothly secured.

1 and 2 are an exploded perspective view and assembled cross-sectional view of the electric compressor according to the present invention,
Figure 3 is a perspective view showing the separation of the swing scroll and the balance weight to form a back pressure space in the electric compressor according to the present invention,
4 is a cross-sectional view showing the assembly of the compression unit including the swing scroll and the balance weight of FIG.
5 is an enlarged cross-sectional view of part “A” of FIG. 4;
6A and 6B are plan views showing an enlarged view of the periphery of the discharge chamber to explain embodiments of the positions of the pressurizing hole and the back pressure hole;
7 is a plan view showing a balance weight according to the present embodiment,
8a to 9b is a cross-sectional view showing the position of the swing scroll according to the difference between the pressure in the compression chamber and the pressure in the back pressure space of the electric compressor of the present invention,
10 is a cross-sectional view showing another embodiment of the back pressure space in the electric compressor according to the present invention.

Hereinafter, the electric compressor according to the present invention will be described in detail based on the embodiment shown in the accompanying drawings.

The motor-driven compressor according to the present invention is a part of a refrigeration cycle apparatus that sucks and compresses a refrigerant, and is a scroll compressor in which two scrolls are engaged to compress the refrigerant. The scroll compressor of the present embodiment uses a carbon dioxide (CO ₂ ) refrigerant to describe a high-temperature, high-pressure electric scroll compressor having a discharge pressure of 100 bar, more precisely about 130 bar, and a discharge temperature of about 170 ° C. as an example. 1 and 2 are an exploded perspective view and assembled cross-sectional view of the electric compressor according to the present invention.

1 and 2, the electric compressor according to the present embodiment may include a casing 101, a main frame 102, a driving unit 103, and a compression unit 104. In addition, the inverter unit 200 for controlling the operation of the compressor may be installed outside the front cover 112 to be described later. Accordingly, the inverter unit 200 may be located on the opposite side of the compression unit 104 with respect to the drive unit 103. In the following description, the inverter unit is set forward and the compression unit opposite to the rear is described.

The casing 101 may include a main housing 111, a front cover 112, and a rear cover 113.

The main housing 111 has a cylindrical shape in which the front end and the rear end are open, the front cover 112 may be coupled to the front end, and the rear cover 113 may be coupled to the rear end, respectively. In addition, the suction space S1 constituting the motor chamber and the rear cover 113 may be formed in the main housing 111 and the discharge space S2 may be formed together with the first scroll 140 to be described later.

The driving unit 103, the frame and the compression unit 104 are accommodated in the suction space S1, and the oil separation unit 116 separating oil from the refrigerant discharged into the discharge space S2 in the discharge space S2. Can be installed.

In addition, an inlet port 111a communicating with the suction space S1 is formed on the sidewall of the main housing 111, and an exhaust port 113a communicating with the discharge space S2 is formed at the sidewall of the rear cover 113. The oil separator 116 described above may be installed at the exhaust port 113a.

In addition, a first oil recovery hole 113b for recovering oil separated from the oil separation unit 116 is formed in the lower half of the rear cover 113, and the first oil recovery hole 113b is formed in the first scroll 140. The second oil recovery hole 142a for guiding the gas oil recovered through the suction chamber V1 may be formed. An orifice 117 may be installed in the first oil recovery hole 113b or the second oil recovery hole 142a to reduce the gas oil guided to the suction chamber V1. Accordingly, the discharge space communicates with the suction chamber V1 through the first oil recovery hole 113b and the second oil recovery hole 142a, so that the oil separated by the oil separation unit 116 is mixed with the gas and the suction chamber. The process of recovery to (V1) is repeated. This will be described later.

On the other hand, the main frame 102 has an annular disk-shaped body portion 121 is formed, the edge of the body portion 121 is the front surface of the scroll side wall portion 142 of the first scroll 140 and the main housing ( It may be supported and coupled between the inner stepped surfaces 111b of the 111. The first sealing member 171 is provided on the bearing surface 150a of the second scroll 150 in contact with the bearing surface 121a of the body portion 121, and is provided between the main frame 102 and the second scroll 150. The thrust bearing surface of the seal will be sealed.

In addition, a balance weight accommodating space part (hereinafter accommodating space part) 122 is formed at the center of the main frame 102 to accommodate the balance weight 136 which will be described later, and a rotating shaft ( The balance weight 136, which is coupled to the 135 and compensates for an imbalance due to the eccentric turning movement of the second scroll 150, may be rotatably received. The balance weight forms a back pressure space together with the second scroll, which will be described later, which will be described again with the back pressure hole.

In addition, the bearing part 123 protrudes toward the front side in the center of the back pressure space part 122, and the shaft hole 124 through which the rotating shaft 135 is rotatably inserted in the center of the bearing part 123 is formed. do. The main bearing 161 described above is fixedly coupled to the inner circumferential surface of the bearing portion 123, and the inner circumferential surface of the shaft hole 124 is spaced apart from the outer circumferential surface of the rotating shaft. Accordingly, the rear side of the accommodation space 122 is sealed by the first sealing member 171, but the front side of the accommodation space 122 is opened to communicate with the suction space S1.

On the other hand, the drive unit 103 includes a stator 131 and a rotor 132, and generates a rotational force for driving the rotary shaft 135. In this embodiment, the stator 131 may be formed in an annular shape to be fixed to the inner circumferential surface of the main housing 111 and to form a cylindrical space therein. The rotor 132 may be spaced apart from the stator 131 in the inner space of the stator 131. The rotor 132 may be formed in a substantially cylindrical shape, the rotation axis 135 may be coupled to the center thereof. When power is supplied to the driving unit 103, the rotor 132 and the rotating shaft 135 may rotate together by the interaction of the stator 131 and the rotor 132.

The rotating shaft 135 may be accommodated in the main housing 111 and may be rotatably supported by the main frame 102. The rear side of the rotation shaft 135 may be radially supported by the main bearing 161 mounted to the main frame 102. An inner ring of the main bearing 161 may be a deep groove ball bearing coupled to the rotation shaft 135 and an outer ring of the main bearing 102 to be pressed into the main frame 102.

In addition, the front end of the rotation shaft 135 may be radially supported by the sub-bearing 162 provided on the front cover 112. The sub bearing 162 may be mounted on the shaft support protrusion 114 formed on the inner surface of the front cover 112. Accordingly, a portion of the outer circumferential surface of the rotation shaft 135 may be coupled to the rotor 132 to receive the rotational force generated by the driving unit 103.

Meanwhile, the compression unit 104 may include a first scroll 140 that is a fixed scroll and a second scroll 150 that is a turning scroll. The second scroll 150 is eccentrically coupled to the rotational shaft 135 coupled to the rotor 132 of the drive unit 103 and rotates with respect to the first scroll 140 while being sucked together with the first scroll 140. Two pairs of compression chambers V are formed of the chamber V1, the intermediate pressure chamber V2, and the discharge chamber V3.

The first scroll 140 is in the shape of a disk is provided with a fixed side plate portion 141, one side of the fixed side plate portion 141 is formed with a scroll side wall portion 142 protruding toward the main frame 102 Can be. A second oil suction hole 142a to be described later may be formed in the scroll side wall portion 142 through the axial direction.

A fixed wrap 143 is formed at the center of the fixed side plate part 141 to form a pair of compression chambers V in engagement with the turning wrap 152 which will be described later. An inlet (not shown) is formed at the edge of the casing 101 to communicate with the suction space S1, and a discharge port 144 communicating with the discharge space S2 in the final compression chamber at the center of the fixed side plate part 141. Can be formed.

The second scroll 150 has a disk-shaped rotating side plate portion 151 is formed, the first side of the rotating side plate portion 151 protrudes toward the fixed side plate portion 141 is fixed wrap 143 and An interlocking pivoting wrap 152 is formed, and a boss groove 153 is formed on the second side of the pivoting side plate 151 so that an eccentric bearing 163 supporting the rotation shaft 135 is inserted and fixed. Accordingly, the second scroll 150 may be coupled to the rotation shaft 135 with the eccentric bearing 163 and the balance weight 136 interposed therebetween to receive the rotational force.

Reference numeral 180 in the drawing is a pin-and-ring type anti-rotation mechanism.

The electric compressor according to the present invention as described above is operated as follows.

That is, when power is applied to the drive unit 103, the rotation shaft 135 rotates together with the rotor 132 of the drive unit 103 to transmit the rotational force to the second scroll 150. Then, the second scroll 150 eccentrically connected to the rotating shaft 135 is rotated by the distance eccentric by the anti-rotation member 180, the compression chamber (V) is the radial center side of the rotation axis 135 The volume decreases as it continues to move toward.

Accordingly, the refrigerant flows into the suction space S1 constituting the motor chamber through the inlet 111a and is sucked into the compression chamber V. At this time, the refrigerant may cool the stator 131 and the rotor 132 while passing through the driving unit 103.

Thereafter, the refrigerant sucked into the compression chamber V is compressed while moving toward the center side along the movement path of the compression chamber V, and is formed between the first scroll 140 and the rear cover 113 through the discharge port 144. It is discharged to the discharge space S2.

The refrigerant discharged into the discharge space S2 is separated from the oil in the discharge space S2 or the oil component is separated while passing through the oil separator 116, and the refrigerant is discharged through the exhaust port 113a in a refrigeration cycle. On the other hand, the separated oil is left in the discharge space (S2) as a gas oil in a mist state mixed with a small amount of refrigerant, the gas oil through the first oil recovery hole and the second oil recovery hole described above ( After being recovered to V1), together with the refrigerant to be sucked again, the intermediate pressure chamber V2 is sucked and compressed, and a series of processes discharged through the discharge chamber V3 is repeated.

On the other hand, the pressure of the back pressure space, that is, the back pressure must be maintained at an appropriate pressure to be able to stably maintain the behavior of the second scroll, which is the turning scroll. If the back pressure is small, the bearing force on the second scroll is weakened, and thus the adhesion force with the first scroll, which is the fixed scroll, is lowered. As a result, leakage in the compression chamber may occur, thereby increasing the compression loss. On the other hand, if the back pressure is too large, the second scroll may be swiveled in an excessively close contact with the first scroll, thereby increasing the friction loss.

In particular, when the CO ₂ refrigerant is applied, the pressure in the back pressure space is about 60 to 70 bar to form a higher back pressure than when other refrigerants (134a, 410a, etc.) are applied. However, the sealing force of the sealing member that seals the back pressure space is not uniform, so that the back pressure space may not be formed smoothly, and the load on the main bearing accommodated in the back pressure space increases to shorten the life of the main bearing. I could make it.

Therefore, in the present invention, the pressure in the back pressure space is interlocked with the pressure in the compression chamber to suppress friction loss or compression loss, and the sealing member forming the back pressure space is supported by the pressure in the compression chamber to increase the sealing force in the back pressure space. In addition, the life of the main bearing can be extended by separating the space where the main bearing is installed and the back pressure space.

Figure 3 is a perspective view of the swing scroll and the balance weight to form a back pressure space in the electric compressor according to the present invention separated, Figure 4 is a cross-sectional view showing the assembly of the compression unit including the swing scroll and the balance weight of Figure 3, 5 is an enlarged cross-sectional view of part “A” of FIG. 4, and FIGS. 6A and 6B are enlarged plan views illustrating the discharge chamber periphery to explain embodiments of the positions of the pressurizing hole and the back pressure hole.

Referring to these drawings, in the motor-driven compressor according to the present embodiment, the back pressure hole 158 is formed in the swing side hard plate portion 151 of the second scroll 150 which is the swing scroll, and is located outward from the back pressure hole 158. A second sealing member 172 for forming the back pressure space S3 may be provided. Accordingly, a part of the refrigerant and oil compressed in the compression chamber V flows into the back pressure space S3 through the back pressure hole 158 to form back pressure.

For example, as shown in FIGS. 3 and 4, the outer side of the boss groove 153 in the radial direction from the second side 151b of the turning side plate part 151, that is, the side facing the balance weight 136. The back pressure protrusion 155 protruding in the axial direction is formed in an annular shape, and a predetermined width and depth may be provided on a front end surface of the back pressure protrusion 155, that is, a surface facing the back pressure surface portion 136c of the balance weight 136 which will be described later. Branch sealing groove 156 is formed in an annular shape. The sealing groove 156 has a width such that the second sealing member 172, which will be described later, is slidably in the axial direction, and has a depth greater than or equal to the axial height of the second sealing member 172. Can be formed.

Accordingly, the second sealing member 172 having an annular shape is inserted into the sealing groove 156 to move in the axial direction according to the difference between the pressure in the compression chamber V and the pressure in the back pressure space S3. The sealing member 172 separates the inner space of the back pressure protrusion 155, more precisely, the inner space of the second sealing member 172 from the outer space to form a back pressure space S3 communicating with the back pressure hole 158. do.

In addition, the sealing groove 156 may be formed with a pressing hole 157 constituting the pressing flow path. The pressure hole 157 communicates the inside of the sealing groove 156 with the compression chamber V to press the flow path for pressing the second sealing member 172 toward the balance weight 136 by the pressure of the compression chamber V. Is achieved.

As shown in FIGS. 4 and 5, the pressing hole 157 is a pivoting side plate portion 151 forming the compression chamber V in the axial side toward the first scroll 140 among the three sides forming the sealing groove 156. It may be penetrated toward the second surface (151b) of the).

In addition, in some cases, the pressing hole 157 may be formed in a straight line, or may be formed to be inclined or stepped. This is exposed to the second side surface 151b of the turning side plate portion 151 to form the inlet of the pressing hole 157 and the position of the first pressing end 157a and the inside of the sealing groove 156 to expose the pressing hole. It may be appropriately formed depending on the position of the second outlet end 157b constituting the outlet end of 157.

In addition, the first pressing end 157a of the pressing hole 157 may be in communication with the intermediate pressure chamber V2 between the suction chamber V1 and the discharge chamber V3 so as to utilize the intermediate pressure. However, depending on the volume of the back pressure space S3, it may be formed to communicate with the discharge chamber V3 to use the discharge pressure, or may be formed to communicate with the intermediate pressure chamber V2 immediately before the discharge chamber. In the present embodiment, as the area of the back pressure space S3 to be described later decreases, the first pressing end 157a of the pressing hole 157 communicates with the discharge chamber V3.

Further, the inner diameter D1 of the pressing hole 157 is sufficient if it is formed between neighboring turning wraps 152, but the inner diameter D1 of the pressing hole 157 is smaller than the cross-sectional area A of the turning wrap 152. If wide, the compression chamber (V) located on both sides of the turning wrap 152 communicates with each other may cause a compression loss. Therefore, it may be preferable that the inner diameter D1 of the pressing hole 157 is smaller than or equal to the cross-sectional area A of the turning wrap. In addition, the inner diameter D1 of the pressing hole 157 may be formed smaller than the width t of the sealing groove 156.

Meanwhile, the back pressure hole 158 described above may be formed in the turning side plate 151. The back pressure hole 158 serves as a back pressure flow path for communicating between the compression chamber V and the back pressure space S3, and may be formed at one side of the pressure hole 157.

The back pressure hole 158 may be formed to communicate with the pressure hole 157, or may be formed independently from the pressure hole 157.

For example, as shown in FIG. 6A, the back pressure holes 158 may be branched in the middle of the pressure holes 157 to communicate with each other. In this case, since the pressure of the compression chamber V for pressing the second sealing member 172 and the pressure of the compression chamber V forming the back pressure become the same, the behavior of the second sealing member 172 is stabilized and compressed. It may be desirable to prevent refrigerant leakage between the chambers (V).

As shown in FIGS. 4 and 5, the first back pressure stage 158a forming the inlet of the back pressure hole 158 is branched to communicate with the middle of the pressure hole 157, and the second back pressure forming the outlet of the back pressure hole 158. The stage 158b may be formed to penetrate between the back pressure protrusion 155 and the boss groove 153. The back pressure hole 158 may be formed to be stepped as shown in the drawing, but this is merely illustrated for convenience and may be formed to be inclined in consideration of workability.

Here, the boss groove 153 may be provided with an eccentric bearing 163 made of a bush bearing, unlike the conventional eccentric bearing. This is because the back pressure protrusion 155 and the second back pressure end 158b of the back pressure hole 158 described above are formed at radial intervals on the second surface 151 b of the turning side plate part 151, so that the back pressure This is because it is advantageous to apply a bush bearing having a relatively small occupied area in order to secure a space necessary for constructing the space S3.

In addition, the inner diameter D2 of the back pressure hole 158 may be formed to have the same inner diameter as the inner diameter D1 of the pressing hole 157, or may be formed to have different inner diameters. However, when the inner diameter D2 of the back pressure hole 158 is formed to have an inner diameter different from the inner diameter D1 of the pressure hole 157, the inner diameter D2 of the back pressure hole 158 is the pressure hole 157. It may be preferable to form smaller than the inner diameter (D1) of. Accordingly, the refrigerant and the oil moving to the back pressure hole 158 through the pressure hole 157 is reduced to a pressure lower than the pressure for pressing the second sealing member 172 to form a back pressure, the second sealing member The sealing force can be improved by pressing 172 by the force by the higher pressure.

In addition, as the inlet of the back pressure hole 158 communicates with the discharge chamber V3 through the pressure hole 157, the required back pressure is required when the area of the discharge chamber V3 and the area of the back pressure space S3 are the same. May not be secured. Accordingly, the inner diameter of the back pressure protrusion 155 forming the back pressure space S3 or the inner diameter of the second sealing member 172 is larger than the inner diameter of the discharge chamber V3, so that the area of the back pressure space S3 is larger than the discharge chamber V3. It is preferable to make it larger than the area of (V3).

Meanwhile, as described above, the back pressure hole 158 may be formed independently from the pressure hole 157. For example, as shown in FIG. 6B, when the back pressure hole 158 is formed independently of the pressure hole 157, at least the pressure hole 157 is located in the same compression chamber V as the compression chamber V through which the pressure hole 157 communicates. It can be formed to.

Accordingly, it may be preferable in terms of the side surface to stabilize the behavior of the second sealing member 172 and the side of suppressing the refrigerant leakage between the compression chamber (V). Furthermore, in the case where the pressurizing hole 157 and the back pressure hole 158 are formed independently, the pressurizing hole 157 and the back pressure hole 158 are not constrained to each other during the processing. ) May be easy to process.

On the other hand, the second sealing member 172 may be formed in a U-shaped or V-shaped cross-sectional shape so that the opening side toward the compression chamber (V) or the back pressure space (S3). However, as the pressure of the compression chamber V is pressed toward the back pressure surface portion to be described later through the pressing hole 157, it may be formed in a rectangular cross-sectional shape as shown in FIG. 4. In this case, the second sealing member 172 may be formed of a lubricity material such as Teflon.

In addition, the second sealing member 172 may be formed in a complete annular annular shape without both ends, or may be formed in a cut annular shape in which both ends are in sliding contact. The second sealing member 172 receives the pressing force in the axial direction through the pressing hole 157, and also receives the back pressure from the inner side to the outer side as it comes into contact with the back pressure space S3. It may be desirable to form a cut annular that is in sliding contact with each other to ensure a sealing force.

On the other hand, one side of the second scroll 150 according to the present embodiment, that is, the front side is provided with a balance weight 136 coupled to the rotating shaft 135, the balance weight 136 and the second scroll 150 Together, the back pressure space S3 is formed. 7 is a plan view showing a balance weight according to the present embodiment.

As shown in the drawing, the balance weight 136 according to the present exemplary embodiment may include an eccentric pin part 136a, an eccentric mass part 136b, and a back pressure surface part 136c.

The center Oe of the eccentric pin portion 136a is eccentrically provided by the turning radius of the second scroll 150 with respect to the axis center (center of the rotor) Oc of the rotation shaft 135, so as to be rearward of the rotation shaft 135. It is fixedly coupled to the stage. The eccentric pin portion 136a is formed in a cylindrical shape and is fixedly coupled to the rear end of the rotation shaft 135 by a fixing pin or fixing bolt (unsigned) passing through the eccentric pin portion 136a.

In addition, the center Oe of the eccentric pin part 136a is preferably formed to be concentric with the center (or center of the back pressure protrusion) Os of the second sealing member 172. If the center Oe of the eccentric pin portion 136a is eccentric with respect to the center of the second sealing member 172 (or the center of the back pressure protrusion) Os, the second sealing member 172 is a balance weight (more This is because the back movement is made about the back pressure surface part 136, and the area of the back pressure surface part 136c must be wider than the area of the same back pressure space S3.

The eccentric mass portion 136b extends radially from the outer circumferential surface of the eccentric pin portion 136a. However, as the eccentric mass portion 136b extends in a semicircular or scalloped shape from one side of the circumferential surface of the eccentric pin portion 136a, the center of mass Ow of the eccentric pin portion 136a with respect to the center Oe of the eccentric pin portion 136a. Eccentrically toward 136b).

The outer diameter of the eccentric mass portion 136b is formed to such an extent that it can rotate in the accommodation space 122 of the main frame 102 described above. For example, the outer diameter of the eccentric mass portion 136b is formed smaller than the inner diameter of the accommodation space 122 on the basis of the axis center Oc of the rotation shaft 135.

The back pressure surface portion 136c extends in the radial direction from the outer circumferential surface of the eccentric pin portion 136a to the opposite side of the eccentric mass portion 136b. For example, the back pressure surface portion 136c extends in a semicircular or fan shape on both sides of the circumferential direction of the eccentric mass portion 136b. Accordingly, the outer circumferential surface of the eccentric mass portion 136b and the outer circumferential surface of the back pressure surface portion 136c are combined to form a circle.

The back pressure surface portion 136c is generally formed such that its outer circumferential surface is circular, similar to the eccentric mass portion 136b, but is not necessarily circular. That is, the outer circumferential surface of the back pressure surface portion 136c is always located outside the inner circumferential surface of the second sealing member 172, so that the back pressure space S3 may be formed inside the second sealing member 172.

In addition, the outer diameter of the back pressure surface portion 136c may be formed in the same manner as the outer diameter of the eccentric mass portion 136b with respect to the center Oe of the eccentric pin portion 136a, but the outer diameter and the eccentric mass of the back pressure surface portion 136c are necessarily. It is not necessary to make the outer diameter of the part 136b the same. On the contrary, when the outer diameter of the back pressure surface portion 136c and the outer diameter of the eccentric mass portion 136b are formed equally, the inner diameter of the accommodation space 122 should be wider to correspond to the outer diameter of the back pressure surface portion 136c. Not. Therefore, as shown in FIG. 7, when the center Oe of the eccentric pin portion 136a is used as a reference, the outer diameter of the back pressure surface portion is preferably smaller than the outer diameter of the eccentric mass portion 136b. Accordingly, the stepped portion 136d may be formed at the point where the eccentric mass portion 136b and the back pressure surface portion 136c are connected.

However, like the outer diameter of the eccentric mass portion 136b, the outer diameter of the back pressure surface portion 136c is formed to be larger than the outer diameter of the second sealing member 172, that is, approximately the same as the outer diameter of the back pressure protrusion 155. It may be advantageous to form the back pressure space (S3).

In addition, the back pressure surface portion 136c may be formed thinner than the eccentric mass portion 136b. Accordingly, the center of gravity Ow of the balance weight 136 may be eccentrically positioned toward the eccentric mass portion 136b as described above. However, the back pressure surface portion 136c may be formed to have the same thickness as the eccentric mass portion 136c. In this case, however, the material of the back pressure surface portion 136c may be formed of a lighter material than the material of the eccentric mass portion 136b so that the center of gravity of the balance weight 136 is eccentrically positioned toward the eccentric mass portion 136b. Do.

On the other hand, the eccentric pin portion 136a, the eccentric mass portion 136b, and the back pressure surface portion 136c constituting the balance weight 136 may be formed of one component, or may be formed by assembling a plurality of components. However, since the back pressure surface portion 136c forms a kind of axial bearing surface in sliding contact with the back pressure protrusion 155 or the second sealing member 172, when considering the roughness of the bearing surface, the eccentric mass portion 136b and the back pressure are considered. It may be advantageous that the face portion 136c is formed in one piece.

Reference numeral 151a in the figure is a first side surface of the pivoting side panel portion facing the first scroll.

Electric compressor according to the present invention as described above has the following effects.

2 and 4 again, the refrigerant sucked into the suction space S1 through the inlet 111a is sucked into the suction chamber V1 by the suction force generated in the compression unit 104, and the refrigerant is removed. It is sucked into the 1st compression chamber and the 2nd compression chamber, respectively. The refrigerant sucked into both compression chambers V is compressed by decreasing the volume as each compression chamber V moves toward the center direction, and the compressed refrigerant moves to the discharge chamber V3 and discharges through the discharge port 144. It is discharged to the discharge space S2.

At this time, the refrigerant discharged from the compression chamber (V) into the discharge space (S2) is separated from the oil in the discharge space (S2) or the oil separation unit 116, the refrigerant is discharged to the refrigeration cycle apparatus through the exhaust port 113a. On the other hand, the gas oil separated from the refrigerant remains in the discharge space S2 in a mist state. The gas oil moves to the suction chamber V1 through the first oil recovery hole 113b, the orifice 117, and the second oil recovery hole 142a due to the pressure difference, and is sucked into the suction chamber V1. It is sucked into the compression chamber (V) with the refrigerant to be.

On the other hand, a part of the refrigerant and oil compressed in the compression unit 104 (exactly, a part of the refrigerant and oil moved through the intermediate pressure chamber to the discharge chamber) is moved to the sealing groove 156 through the pressure hole 157. At the same time, a portion of the refrigerant and the oil that has moved toward the sealing groove 156 through the pressure hole 157 through the back pressure hole 158 communicated with the side of the pressure hole 157 moves toward the back pressure space S3. Done.

Then, the second sealing member 172 is pushed toward the front side, that is, the back pressure surface portion 136c of the balance weight 136 by the pressure of the refrigerant and the oil moving to the sealing groove 156 through the pressure hole 157. As the second sealing member 172 is in close contact with the back pressure surface portion 136c, the inner space of the back pressure protrusion 155, that is, the back pressure space S3 is sealed.

Then, the back pressure space S3 forms a back pressure substantially equal to the discharge pressure by the refrigerant and the oil moving to the back pressure space S3 through the back pressure hole 158. However, as the radial area of the back pressure space S3 is made larger than the radial area of the discharge chamber V3, the necessary back pressure for supporting the second scroll 150 toward the first scroll 140 may be secured. It becomes possible.

Then, the second scroll 150 is floated toward the first scroll 140, so that the end surface of the fixed wrap 143 is in contact with the first side surface 151a of the turning side plate 151. In this state, when the second scroll 150 rotates, the compression chamber (exactly, the discharge chamber) is repeated while the first pressing end 157a of the pressing hole 157 is opened and closed by the fixing wrap 143. The refrigerant and oil between (V) and the back pressure space (S3) are moved in both directions according to the pressure difference.

8A to 9B are cross-sectional views showing the position of the turning scroll according to the difference between the pressure in the compression chamber and the pressure in the back pressure space in the electric compressor of the present invention.

For example, as shown in FIG. 8A, when the back pressure of the back pressure space S3 is higher than the required back pressure, the second scroll 150 floats and wraps 143 and 152 of both scrolls 140 and 150. And the hard plate portion 151, 141 is in a state of being in close contact. This may increase the friction loss between the wraps 143 and 152 of both scrolls 140 and 150. However, as shown in FIG. 8B, when the second scroll 150 is rotated further, the pressurizing hole 157 and the back pressure hole 158 are opened, and the refrigerant and oil in the back pressure space S3 are compressed in the compression chamber ( For example, it moves to discharge chamber (V). Then, the back pressure of the back pressure space (S3) is instantaneously lowered, thereby reducing the frictional loss while reducing the adhesion between both scrolls (140, 150).

On the other hand, as shown in FIG. 9A, when the back pressure of the back pressure space S3 is lower than the required back pressure as in the start of the compressor, the second scroll 150 is not sufficiently raised. Then, the compression loss may increase while being spaced apart between the wraps 143 and 152 of the scrolls 140 and 150 and the hard plate portions 151 and 141. However, as shown in FIG. 9B, the refrigerant and the oil in the compression chamber (for example, the discharge chamber) V move to the back pressure space S3, and the pressure in the back pressure space S3 is momentarily increased to provide the necessary back pressure. Will be reached. Then, the second scroll 150 is quickly floated, and the wrap 143 and 152 of the both scrolls 140 and 150 are in contact with the hard plate part 151 and 141, thereby suppressing compression leakage.

In this way, according to the present invention, as the pressure in the back pressure space is linked with the pressure in the compression chamber, the pressure in the back pressure space is varied in response to the pressure change in the compression chamber, thereby maintaining the required back pressure. Through this, it is possible to suppress friction loss that may occur when the pressure in the back pressure space is higher than the required back pressure, while suppressing compression loss that may occur when the pressure in the back pressure space is lower than the required back pressure.

In the present invention, a back pressure space is formed between the second scroll and the balance weight, and a back pressure hole is formed in the second scroll so that the back pressure space and the compression chamber communicate with each other. As a result, the length of the back pressure hole is shortened, so that the pressure in the back pressure space can be promptly formed. Furthermore, as the refrigerant and the oil immediately before the discharge chamber or the discharge chamber are introduced into the back pressure space to form the back pressure, the volume of the back pressure space can be reduced, and the necessary back pressure can be secured quickly. Furthermore, as the main bearing supporting the rotating shaft is installed outside the back pressure space, the load on the main bearing can be reduced. This can extend the life of the main bearing.

In addition, according to the present invention, as the sealing member forming the back pressure space is supported in the axial direction by the pressing hole communicated with the compression chamber, the sealing force of the sealing member can be improved. As a result, even when a high pressure refrigerant such as a CO ₂ refrigerant is applied, the back pressure space can be effectively sealed, thereby ensuring necessary back pressure.

On the other hand, when there is another embodiment for the back pressure space in the electric compressor according to the present invention. 10 is a cross-sectional view showing another embodiment of the back pressure space in the electric compressor according to the present invention.

That is, in the above-described embodiment, the back pressure space is formed by forming the back pressure protrusion on the second side surface of the second scroll, but in the present embodiment, the back pressure space formed as the groove is formed in the second scroll.

For example, as shown in FIG. 10, in the present embodiment, a back pressure space 159 having a predetermined width and depth is formed in a recess shape on a second side surface 151 b of the second scroll 150 to form a back pressure space ( S3) can be formed. As the back pressure space 159 is formed with a boss groove 153 in the center thereof, the back pressure space 159 may be formed in an annular shape.

Even in this case, the sealing groove 156 described above is formed in an annular shape on the outer surface of the back pressure space portion 159, and the pressure passage 157 described above is formed in the sealing groove 156 so as to pass through the back pressure space portion ( The back pressure passage 158 described above may be formed inside the 159. The pressurizing flow passage 157 may be branched in the middle of the back pressure hole 158 as in the above-described embodiment, or may be formed independently of the back pressure flow passage 158.

As described above, the electric compressor to which the back pressure space according to the present embodiment is applied is similar in basic construction and operation effects of the electric compressor to which the above back pressure space is applied, and thus a detailed description thereof will be omitted.

However, when the back pressure protrusion 155 of the above-described embodiment is removed and the back pressure space 159 is formed in a recess shape as in the present embodiment, the balance weight 136 is disposed closer to the compression chamber V. As a result, the size of the eccentric mass portion of the balance weight 136 can be reduced. Then, the input to the driving motor 103 can be reduced, so that the compressor efficiency can be improved.

Meanwhile, in the above-described embodiment, the electric compressor to which the CO 2 refrigerant is applied has been described, but is not limited thereto.

What has been described above is merely an embodiment for carrying out the electric compressor according to the present invention, and the present invention is not limited to the above embodiment, and does not depart from the gist of the present invention as claimed in the following claims. Anyone with ordinary knowledge in the field of the present invention will have the technical idea of the present invention to the extent that various modifications can be made.

111: main housing 112: front cover
113: rear cover 113a: first oil return hole
116: oil separator 102: main frame
121: body portion 122: accommodation space portion
123: bearing portion 124: shaft hole
131: stator 132: rotor
135: rotation axis 136: balance weight
136a: eccentric pin part 136b: eccentric mass part
136c: back pressure surface 140: first scroll
141: fixed side plate portion 142: scroll side wall portion
143: fixed wrap 144: discharge port
150: second scroll 151: pivoting side plate portion
152: Turning Lab 153: Boss Home
155: back pressure protrusion 156: sealing groove
157: pressure hole 158: back pressure hole
159: back pressure space 161: main bearing
162: sub bearing 163: eccentric bearing
171: first sealing member 172: second sealing member
S1: suction space (motor room) S2: discharge space
S3: back pressure space

Claims (16)

A casing provided with a motor compartment;
A frame provided at one side of the motor chamber;
A drive motor accommodated in the motor chamber at one side of the frame;
A first scroll supported on the other side of the frame and having a spiral wrap formed thereon;
A second scroll having a spiral wrap to be engaged with the wrap of the first scroll and forming a compression chamber between the wraps while being swiveled by a rotational force of the driving motor;
One end is coupled to the rotor of the drive motor, the other end is eccentrically coupled to the second scroll, the rotating shaft for transmitting the rotational force of the drive motor to the second scroll;
A balance weight provided to face the rear surface of the second scroll and coupled to the rotation shaft;
A sealing member provided between the rear surface of the second scroll and the opposing surface of the balance weight to form a back pressure space between the rear surface of the second scroll and the opposing surface of the balance weight; And
And a back pressure passage provided through the second scroll to communicate between the compression chamber and the back pressure space.
The second scroll is provided with an annular sealing groove so that the sealing member is slidably inserted in the axial direction.
And a pressurized flow passage communicating with the sealing groove and the compression chamber through the second scroll. delete The method of claim 1,
The pressurized flow path is an electric compressor, characterized in that formed less than or equal to the thickness of the wrap of the first scroll. The method of claim 3,
And the pressurized flow passage communicates with the compression chamber immediately before the compressed refrigerant is discharged or the compression chamber discharged from the compression chamber. The method of claim 4, wherein
The radial area of the back pressure space is an electric compressor, characterized in that formed larger than or equal to the radial area of the compression chamber in which the pressurized flow path communicates. The method of claim 1,
And the back pressure passage and the pressurized passage are formed to communicate with each other. The method of claim 6,
The back pressure flow path is an electric compressor, characterized in that the inner diameter is formed to be less than or equal to the inner diameter of the pressurized flow path. The method of claim 1,
And the back pressure passage and the pressurized passage are independently formed so as not to communicate with each other in the second scroll. The method of claim 8,
And the back pressure passage and the pressurized passage are formed to communicate with the same compression chamber. A casing provided with a motor compartment;
A frame provided at one side of the motor chamber;
A drive motor accommodated in the motor chamber at one side of the frame;
A first scroll supported on the other side of the frame and having a spiral wrap formed thereon;
A second scroll having a spiral wrap to be engaged with the wrap of the first scroll and forming a compression chamber between the wraps while being swiveled by a rotational force of the driving motor;
One end is coupled to the rotor of the drive motor, the other end is eccentrically coupled to the second scroll, the rotating shaft for transmitting the rotational force of the drive motor to the second scroll;
A balance weight provided to face the rear surface of the second scroll and coupled to the rotation shaft;
A sealing member provided between the rear surface of the second scroll and the opposing surface of the balance weight to form a back pressure space between the rear surface of the second scroll and the opposing surface of the balance weight; And
And a back pressure passage provided through the second scroll to communicate between the compression chamber and the back pressure space.
The second scroll has a back pressure protrusion protruding annularly toward the balance weight,
The back pressure protrusion is formed with a sealing groove in which the sealing member is inserted to slide in the axial direction,
And the back pressure flow passage is formed to penetrate inward from the inner circumferential surface of the back pressure protrusion. A casing provided with a motor compartment;
A frame provided at one side of the motor chamber;
A drive motor accommodated in the motor chamber at one side of the frame;
A first scroll supported on the other side of the frame and having a spiral wrap formed thereon;
A second scroll having a spiral wrap to be engaged with the wrap of the first scroll and forming a compression chamber between the wraps while being swiveled by a rotational force of the driving motor;
One end is coupled to the rotor of the drive motor, the other end is eccentrically coupled to the second scroll, the rotating shaft for transmitting the rotational force of the drive motor to the second scroll;
A balance weight provided to face the rear surface of the second scroll and coupled to the rotation shaft;
A sealing member provided between the rear surface of the second scroll and the opposing surface of the balance weight to form a back pressure space between the rear surface of the second scroll and the opposing surface of the balance weight; And
And a back pressure passage provided through the second scroll to communicate between the compression chamber and the back pressure space.
The second scroll is formed with a back pressure space groove recessed by a predetermined depth in the surface facing the balance weight,
A sealing groove is formed in the outer side of the back pressure space groove to be inserted in the sealing member to slide in the axial direction,
The back pressure flow path is an electric compressor, characterized in that formed to penetrate the interior of the back pressure space groove. The method according to any one of claims 1 and 3 to 11,
The balance weight,
An eccentric pin part fixed to the rotation shaft and coupled to the second scroll;
An eccentric mass portion extending from the eccentric pin portion, the center of gravity of which is located eccentrically from the center of the rotating shaft; And
And a back pressure surface portion extending from the eccentric pin portion in the radial direction to the opposite side of the eccentric mass portion to form a back pressure space portion together with the eccentric mass portion. The method according to any one of claims 1 and 3 to 11,
The frame is provided with a receiving space accommodating the balance weight, the accommodating space portion is characterized in that the electric compressor communicates with the motor compartment. The method of claim 13,
A bearing support is formed stepped on one side of the accommodating space, and the bearing support is provided with a ball bearing for supporting the rotating shaft. The method according to any one of claims 1 and 3 to 11,
The second scroll is formed with a boss groove to which the rotation shaft is coupled, the electric compressor characterized in that the bush bearing is provided between the inner peripheral surface of the boss groove and the outer peripheral surface of the rotary shaft. The method according to any one of claims 1 and 3 to 11,
The casing is formed with a discharge space to accommodate the refrigerant and oil discharged from the compression chamber,
The discharge space is formed with an oil recovery passage for guiding the refrigerant and oil in the discharge space to the suction side of the compression chamber,
The oil return passage is provided with a pressure reducing member.

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