JP4845409B2 - Hermetic compressor - Google Patents

Description

  The present invention relates to a hermetic compressor used for refrigeration, air conditioning, and the like, and more particularly to a technique for improving COP of a hermetic compressor.

2. Description of the Related Art Conventionally, a hermetic rotary compressor in which an electric element and a rotary compression element that is driven by the electric element and compresses a refrigerant is housed in an airtight container is known. In this type of hermetic rotary compressor, generally, a roller that rotates eccentrically is installed in a cylinder with a predetermined clearance to form a crescent-shaped space (so-called compression chamber) in the cylinder, and the roller slides on the roller. A vane that is in contact is provided, and the crescent-shaped space in the cylinder is configured to be pressure-divided by the vane into a low-pressure chamber side that sucks in the refrigerant and a high-pressure chamber side that compresses the refrigerant (for example, Patent Document 1).
JP-A-6-323276

However, in the conventional technology, the sealing performance of the crescent-shaped space in the cylinder is not sufficiently improved, and the cooling efficiency (COP: Coefficient Of Performance: refrigeration capacity / input power) of the hermetic rotary compressor is not achieved. ).
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a hermetic compressor that can improve the sealing performance between a roller and a cylinder and thereby increase the cooling efficiency. And

To achieve the above object, the present invention includes: a motor element in a sealed container, the rotary compression element and the hermetic compressor that houses a for compressing refrigerant is driven by the electric element, the rotary shaft of said rotary compression element The rotary compression element includes the cylinder disposed between the main bearing and the sub-bearing that supports the rotary bearing, and a roller that is installed in the cylinder and rotates eccentrically by the rotary shaft. An oil passage that extends horizontally from one end opened to the compression chamber between the cylinder and the roller to be opened and the other end opens into the sealed container and guides the oil in the sealed container during the suction process. The cylinder and the main bearing Alternatively, a groove is formed between the auxiliary bearing and the ratio R between the sectional area D of the opening at the one end and the displacement volume V of the compression chamber is 0.004 to 0.03 (mm ² / cc). And said oil Provided in a state where the opening and closing valve and biased to open the path for opening and closing the way to the path the path of the guides to the compressed refrigerant compressed against the bias of the on-off valve by the rotary compressing element When the pressure of the compressed refrigerant is low, the open / close valve is opened by the biasing by acting on the open / close valve.

  Further, the present invention is characterized in that, in the above invention, a compressed refrigerant introduction passage is provided for guiding the compressed refrigerant discharged from the discharge pipe of the closed container to the on-off valve.

According to the present invention, the oil passage for guiding the oil in the hermetic container during the suction process is provided in the compression chamber between the cylinder and the roller constituting the rotary compression element. A sufficient oil film is formed to improve the sealing performance. As a result, the refrigerant is prevented from leaking to the low pressure side during the compression process in the compression chamber, so that the compression efficiency is enhanced, and thus the cooling efficiency is enhanced.
In particular, according to the present invention, the compressed refrigerant compressed by the rotary compression element is applied to the on-off valve so that the on-off valve is opened when the pressure difference of the compressed refrigerant is small. Oil injection can be performed only under certain operating conditions (low speed rotation and low pressure difference), which greatly improves cooling efficiency while suppressing the consumption of oil stored in a sealed container. Can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an aspect of a hermetic rotary compressor 100 according to the present embodiment, and FIG. 2 is an enlarged longitudinal sectional view showing a rotary compression element. The hermetic rotary compressor 100 is connected to a pipe between a refrigerant condenser and an evaporator to form a refrigerator unit. As shown in FIG. An electric element 2 is housed on the upper side of the container 1, and a rotary compression element 4 that is driven by a crankshaft 3 (rotary shaft) of the electric element 2 to compress the refrigerant is housed on the lower side.

  The hermetic container 1 includes a cylindrical shell portion 10 and an end cap 11 fixed to the shell portion 10 by arc welding or the like. The end cap 11 is a relay terminal for supplying electric power to the electric element 2. And a discharge pipe 13 for discharging the compressed refrigerant to the outside of the machine. A suction pipe 6 that guides the refrigerant from the accumulator 5 to the rotary compression element 4 is fixed by welding or the like near the bottom of the shell portion 10.

  The electric element 2 is composed of a direct current motor such as a so-called DC brushless motor, and includes a rotor (rotor) 31 and a stator (stator) 32 fixed to the shell portion 10. 3 is fixed, and the rotational force of the rotor 31 is transmitted to the rotary compression element 4. The crankshaft 3 is rotatably supported by a main bearing 7A (support member) and a sub bearing 7B.

  As shown in FIGS. 1 and 2, the rotary compression element 4 includes a cylinder 41 having a cylindrical shape. The cylinder 41 is connected to a main bearing by a bolt or the like (not shown) between the main bearing 7A and the auxiliary bearing 7B. The main bearing 7A is fixed to the inner surface of the sealed container 1 by welding, and the cylinder 41 is supported by the main bearing 7A. Further, the upper opening of the cylinder 41 is closed by the main bearing 7 </ b> A and the lower opening is closed by the auxiliary bearing 7 </ b> B, and a compression chamber 43 is formed in the cylinder 41.

  In the compression chamber 43, a roller 45 that is fitted into an eccentric portion 44 that is integrally formed with the crankshaft 3 and rotates eccentrically is provided. As shown in FIG. 3, the cylinder 41 is provided with a vane groove 47 between the refrigerant suction port 48 and the discharge port 40, and the vane 46 is slidably disposed in the vane groove 47. ing. The vane 46 is always pressed in the direction of the roller 45 by a biasing member such as a spring (not shown), and reciprocates in the vane groove 47 while sliding on the outer peripheral surface of the roller 45 in accordance with the rotation of the eccentric portion 44 and the roller 45. The inside of the compression chamber 43 serves to partition the pressure chamber side into the low pressure chamber side 43A and the high pressure chamber side 43B.

  Specifically, the roller 45 is provided such that one end of the outer surface thereof is always in contact with the inner surface 49 of the cylinder 41 with a predetermined clearance, and the compression chamber 43 that is a space between the cylinder 41 and the roller 45 has a crescent shape. Formed. The vane 46 comes into contact with the outer surface of the roller 45, and the crescent-shaped compression chamber 43 is partitioned by the vane 46 into a low pressure chamber side 43A and a high pressure chamber side 43B.

As shown in FIGS. 1 and 2, the suction pipe 6 is inserted into the suction port 48 of the cylinder 41, and a discharge valve (not shown) is provided in the discharge port 40. When the discharge pressure defined by the valve is reached, it is discharged from the discharge port 40 into the sealed container 1.
Therefore, in the hermetic rotary compressor 100, the electric element 2 is supplied from the outside through the accumulator 5 by rotating the roller 45 eccentrically in the compression chamber 43 by driving the crankshaft 3 to rotate. The refrigerant is sucked into the low-pressure chamber side 43A of the compression chamber 43 through the suction pipe 6, compressed while moving the refrigerant to the high-pressure chamber side 43B, and discharged from the discharge port 40 into the sealed container 1, and the discharge pipe 13 Will be discharged out of the machine.

  As shown in FIGS. 1 and 2, oil 8 is stored at the bottom of the sealed container 1 up to the lower surface of the main bearing 7A (indicated by the line AA ′ in the figure). An oil pickup 50 (oil supply device) for supplying oil to the main bearing 7A, the sub-bearing 7B, the rubbing portion between the rotary compression element 4 and the crankshaft 3 and the sliding portion of the rotary compression element 4 is a lower end portion of the crankshaft 3. 3A is provided.

  Specifically, the crankshaft 3 is formed in a cylindrical shape, and a cylindrical oil pickup 50 is press-fitted and attached to the lower end portion 3A thereof. As shown in FIG. 2, a paddle 51 constituting a spiral oil flow path is integrally formed inside the oil pickup 50, and the oil pickup 50 is separated from the lower end 50A by a centrifugal force generated by the rotation of the crack shaft 3. The oil 8 stored in the airtight container 1 is sucked, and the paddle 51 feeds the oil 8 upward. Then, the oil 8 passes through an oil supply hole 52 formed in the oil pickup 50, and the peripheral surface of the crankshaft 3, in particular, the main bearing 7 </ b> A, the sub-bearing 7 </ b> B, and each sliding portion between the rotary compression element 4 and the crankshaft 3. To be supplied.

Here, as described above, since the roller 45 is installed so as to be always in contact with the inner surface 49 of the cylinder 41 with a predetermined clearance, the sealing performance of the compression chamber 43 is not sufficient and the cooling efficiency is lowered. Will be invited.
Therefore, in the present embodiment, the oil rotary 60 that guides the oil 8 stored in the sealed container 1 to the compression chamber 43 during the refrigerant suction process is provided in the sealed rotary compressor 100, and the oil path 60 is A sufficient oil film is formed between the roller 45 and the cylinder 41 by the oil 8 injected therethrough so as to improve the sealing performance. Hereinafter, this configuration will be described in detail.

  As shown in FIG. 4, step portions 70 </ b> A and 70 </ b> B constituting contact surfaces with the main bearing 7 </ b> A and the sub-bearing 7 </ b> B are formed on the upper and lower surfaces of the cylinder 41. Then, a groove 61 is formed by cutting in the lower step portion 70B on the cylinder 41 side that comes into contact with the sub-bearing 7B, and the step portion 70B and the sub-bearing 7B are brought into contact with each other to form an inner surface 49 of the cylinder 41. An oil passage 60 is formed in which one end 60A is opened and the other end 60B is opened at the outer peripheral end 7B1 of the auxiliary bearing 7B. In the case where the main bearing 7A is immersed in the oil 8, the oil passage 60 may be configured by forming a groove 61 in the step portion 70A on the cylinder 41 side that contacts the main bearing 7A.

  One end 60A of the oil passage 60 is formed so as to open to the cylinder inner surface 49 of the low-pressure chamber side 43A in order to inject the oil 8 into the compression chamber 43 during the step of sucking the refrigerant into the compression chamber 43. 3, one end 60A of the oil passage 60 has a predetermined angle θ1 to θ2 (θ1: 0 °, θ2: 170) with reference to a reference line L connecting the suction port 48 and the center point O of the cylinder 41. It is formed so as to open in the range of θ, more desirably θ1: 125 °, θ2: 165 ° (about 125 ° in the illustrated example).

  Since the refrigerant discharge pressure (for example, 3 MPa) is acting on the oil 8 in the sealed container 1 under the above configuration, the high pressure oil 8 is applied to the internal pressure (for example, 1 on the low pressure chamber side 43A of the compression chamber 43). .1 MPa) is injected into the low pressure chamber side 43 </ b> A of the compression chamber 43 of the cylinder 41 via the oil passage 60.

  Therefore, the oil 8 is injected into the compression chamber 43 during the refrigerant suction process, and a sufficient oil film is formed between the cylinder inner surface 49 and the roller 45 by the oil 8 to improve the sealing performance. As a result, the low pressure chamber side 43A and the high pressure chamber side 43B are more reliably separated in the compression chamber 43 of the cylinder 41, so that the refrigerant sucked into the low pressure chamber side 43A is compressed into the high pressure chamber side 43B (compression In the step), leakage of the compressed refrigerant to the low-pressure chamber side 43A is prevented, and the compression efficiency of the refrigerant is increased, so that the cooling efficiency of the hermetic rotary compressor 100 is improved.

Further, in the present embodiment, the amount of oil injected into the compression chamber 43 is adjusted by adjusting the cross-sectional area D of the oil passage 60 that opens to the cylinder inner surface 49 (that is, the cross-sectional area of the groove 61). At this time, the cross-sectional area D of the oil passage 60 is determined so that the ratio R (= D / V) of the displacement volume of the compression chamber 43 to V falls within a predetermined range. In detail, when the ratio R is too small, the oil passage 60 becomes too narrow and the oil 8 is not injected into the compression chamber 43. On the contrary, when the ratio R is too large. If the oil 8 is excessively injected into the compression chamber 43, liquid compression occurs. Therefore, it is desirable to keep the ratio R in the range of 0.004 to 0.03 (mm ² / cc), thereby preventing liquid compression due to excessive injection of the oil 8 and preventing the cylinder inner surface 49 and the roller from being compressed. The sealing property between 45 is improved.

  By the way, when the rotary compression element 4 is driven in a high frequency region and rotated at a high speed, it is driven in a low frequency region (for example, 15 Hz to 30 Hz) and the differential pressure between the discharge pressure and the suction pressure is smaller. The effect of sealing by oil injection into the compression chamber 43 is great. Therefore, by limiting the oil injection into the compression chamber 43 when the differential pressure is small, it is possible to efficiently improve the cooling efficiency while suppressing the consumption of the oil 8 stored in the sealed container 1. Become. Therefore, in the present embodiment, the opening / closing valve 80 is provided in the oil passage 62, and the opening / closing valve 80 is opened only when the pressure difference of the compressed refrigerant compressed by the rotary compression element 4 is small. 8 is injected.

  More specifically, the cylinder 41 is provided with a through-hole 71 that passes through the oil passage 60 in a cylindrical shape vertically (thickness direction), and an on-off valve 80 is provided in the through-hole 71. The on-off valve 80 is a substantially cylindrical valve body 81 that is inserted into the through hole 71, and a spring 82 that is provided inside the valve body 81 and serves as a biasing member that biases the valve body 81 toward the main bearing 7A. And is configured. When the valve body 81 is pushed up to the main bearing 7A side by the urging force of the spring 82 (open state), a gap is generated between the bottom 81A of the valve body 81 and the upper surface of the sub-bearing 7B. The oil passage 60 cut by the hole 71 communicates, and oil is injected into the compression chamber 43.

  The main bearing 7A is provided with a recess 72 corresponding to the through hole 71. When the valve body 81 is pushed up by the spring 82, the upper portion 81B of the valve body 81 is in contact with the upper surface of the recess 72. . One end of a compressed refrigerant introduction path 90 provided in the main bearing 7 </ b> A is connected to the recess 72, and the other end of the compressed refrigerant introduction path 90 is connected to an introduction pipe 91 that is fixed through the sealed container 1. Is done. As shown in FIG. 1, a part of the compressed refrigerant discharged from the discharge pipe 13 of the hermetic container 1 is guided to the introduction pipe 91 via a connection pipe (not shown), and then via the compression introduction path 90. The pressure of the compressed refrigerant acts on the upper portion 81B of the valve body 81. At this time, the spring constant (biasing force) of the spring 82 is determined so that the valve body 81 is pushed down when the differential pressure between the pressure of the compressed refrigerant and the suction pressure exceeds a predetermined value.

  Therefore, while the pressure difference of the compressed refrigerant is small, the valve body 81 is pushed up to the main bearing 7A side by the urging force of the spring 82, and the oil passage 60 is connected, that is, the open state. Further, when the discharge pressure of the rotary compression element 4 increases and the differential pressure from the suction pressure increases, the valve body 81 is pushed down against the bias of the spring 82 by the pressure of the compressed refrigerant, and the valve body The oil passage 60 is closed by the bottom 81 </ b> A of 81, and the injection of the oil 8 in the compression chamber 43 is stopped.

  As a result, oil injection into the compression chamber 43 is limited to low-frequency driving and low-pressure differential driving of the rotary compression element 4, and the cooling efficiency is improved while suppressing the consumption of the oil 8 stored in the sealed container 1 Can be efficiently achieved.

  As described above, according to the present embodiment, the compression chamber 43 between the cylinder 41 and the roller 45 is provided with the oil passage 62 that guides the oil 8 in the sealed container 1 during the suction process. A sufficient oil film is formed between the cylinder 41 and the roller 45 by the oil 8 injected into the chamber 43, and the sealing performance is improved. Therefore, the refrigerant is prevented from leaking to the low pressure chamber side 43A during the compression process in the compression chamber 43, so that the compression efficiency is increased, and thus the cooling efficiency of the hermetic compressor 100 can be increased.

  In particular, according to the present embodiment, when the pressure difference of the compressed refrigerant is small, that is, the opening / closing state that is opened only while the differential pressure between the discharge pressure and the suction pressure of the rotary compression element 4 is driven. Since the valve 80 is provided in the oil passage 62, oil injection into the compression chamber 43 is limited when the rotary compression element 4 is driven at a low frequency and at a low differential pressure, and is thereby stored in the sealed container 1. It is possible to efficiently improve the cooling efficiency while suppressing the consumption of the oil 8.

  Further, according to the present embodiment, the ratio between the cross-sectional area D of the oil passage 60 and the excluded volume V of the compression chamber 43 is set within a predetermined range, so that liquid compression due to excessive injection of the oil 8 is prevented. However, the sealing performance between the cylinder inner surface 49 and the roller 45 can be enhanced.

  Note that the above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified within the scope of the present invention. For example, in the above-described embodiment, the hermetic rotary compressor 100 including one cylinder 41 is illustrated. However, the present invention is not limited thereto, and the present invention is also applied to the hermetic rotary compressor 100 having two cylinders. Of course it is possible.

It is a longitudinal section showing one mode of a hermetic rotary compressor concerning an embodiment of the invention. It is a longitudinal cross-sectional view which expands and shows a rotation compression element. It is a top view of a cylinder. It is a longitudinal cross-sectional view which expands and shows an oil path and an on-off valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric element 4 Rotation compression element 7A Main bearing 7B Sub bearing 8 Oil 41 Cylinder 43 Compression chamber 43A Low pressure chamber side 43B High pressure chamber side 45 Roller 46 Vane 48 Suction port 60 Oil path 80 On-off valve 90 Compressed refrigerant introduction path

Claims (2)

In a hermetic compressor containing an electric element in a hermetic container and a rotary compression element that is driven by the electric element and compresses refrigerant,
The rotary compression element comprises a cylinder disposed between a main bearing and a sub-bearing for supporting a rotary shaft of the rotary compression element, and a roller installed in the cylinder and rotated eccentrically by the rotary shaft. ,
An oil passage extending horizontally from one end opened in a compression chamber between a cylinder and a roller constituting the rotary compression element and having the other end opened in the sealed container and guides oil in the sealed container during the suction process. A groove is formed between the cylinder and the main bearing or the sub-bearing, and the ratio R between the sectional area D of the opening at the one end and the displacement volume V of the compression chamber is 0.004 to 0.03. (Mm ² / cc)
An on-off valve that opens and closes the passage is provided in the middle of the oil passage so as to open the passage, and the compressed refrigerant compressed by the rotary compression element is resisted against the bias of the on-off valve. by acting on the opening and closing valve guides, hermetic compressor, characterized in that the said opening and closing valve when the pressure of the compressed refrigerant is low is set to be opened by the biasing.   2. The hermetic compressor according to claim 1, further comprising a compressed refrigerant introduction path that guides the compressed refrigerant discharged from a discharge pipe of the sealed container to the on-off valve.

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