JP5212148B2 - Hermetic compressor and refrigeration system - Google Patents

Description

  The present invention relates to a hermetic compressor and a refrigeration apparatus used in a refrigeration cycle such as a refrigerator-freezer.

  In recent years, regarding hermetic compressors used in refrigeration apparatuses such as refrigerators and refrigerators, in addition to high efficiency for reducing power consumption, low noise and high reliability are desired. As a conventional hermetic compressor of this type, there is one in which efficiency and reliability are improved by improving a method for supplying oil to a connecting portion between a connecting rod and a piston (see, for example, Patent Document 1).

  The conventional hermetic compressor will be described below with reference to the drawings.

  7 is a vertical cross-sectional view of a conventional hermetic compressor described in Patent Document 1, FIG. 8 is an enlarged cross-sectional view of the main part of FIG. 7, and FIG. 9 is a cross-sectional view of the main part of FIG. It is.

  As shown in FIGS. 7 to 9, the hermetic container 1 contains an electric element 4 having a stator 2 and a rotor 3, and a compression element 5 driven by the electric element 4, and Lubricating oil 6 is stored at the bottom of the sealed container 1. The shaft 10 has a main shaft portion 11 and an eccentric shaft portion 12 formed eccentrically at one end so as to move integrally with the main shaft portion 11, and of these, the main shaft portion 11 is located at the axis of the rotor 3. It is fixed.

  The cylinder block 14 has a substantially cylindrical compression chamber 15 and a bearing portion 20 that are arranged so as to be fixed to each other at a fixed position. A piston 23 is inserted into the compression chamber 15 so as to be able to reciprocate.

  A piston pin 25 is attached to the piston 23 so as to be parallel to the eccentric shaft portion 12. The bearing portion 20 forms a cantilever bearing by pivotally supporting the end portion on the eccentric shaft portion 12 side of the main shaft portion 11 of the shaft 10.

  The connecting rod 26 includes a large end hole portion 28, a small end hole portion 29, and a rod portion 30. The large end hole portion 28 is fitted to the eccentric shaft portion 12, and the small end hole portion 29 is a piston pin. 25, whereby the eccentric shaft portion 12 and the piston 23 are connected. Further, when the piston pin 25 and the small end hole 29 come into contact with the inner wall of the small end hole 29 in the vicinity of the center in the axial direction of the small end hole 29, both end portions in the axial direction of the small end hole 29 are provided. A convex spherical portion 31 is formed so as to form a gap in each of the two.

  An oil supply passage 35 is provided inside the shaft 10, and an oil distribution pipe 36 is inserted into the end of the oil supply passage 35 on the eccentric shaft portion 12 side. Further, the end portion of the main shaft portion 11 opposite to the eccentric shaft portion 12, that is, the lower end portion 40 extends so that the lubricating oil 6 enters the oil supply passage 35 to a predetermined depth.

  The operation of the hermetic compressor configured as described above will be described below.

  The rotor 3 of the electric element 4 rotates the shaft 10, and the rotational movement of the eccentric shaft portion 12 is transmitted to the piston 23 via the connecting rod 26, whereby the piston 23 reciprocates in the compression chamber 15. Due to the reciprocating motion of the piston 23, the refrigerant gas is sucked into the compression chamber 15 from the cooling system (not shown), compressed, and then discharged to the cooling system again.

  The lower end portion of the oil supply passage 35 performs a pump action by the rotation of the shaft 10, and by this pump action, the lubricating oil 6 at the bottom of the sealed container 1 is pumped upward through the oil supply passage 35. . As indicated by an arrow X, the lubricating oil 6 reaching the upper part of the oil supply passage 35 is scattered horizontally from the upper part of the oil distribution pipe 36 in the entire circumferential direction in the sealed container 1 by a centrifugal force, and a part thereof is a piston pin. 25, piston 23, etc. are supplied for lubrication.

  Further, since the inner wall of the small end hole 29 is a convex spherical portion 31, even if a force that squeezes the connecting rod 26 is generated, the contact portion of the spherical portion 31 is displaced, so that it is small from the piston pin 25. The local twisting with the end hole 29 can be prevented, and a large amount of the lubricating oil 6 can be supplied to the sliding portion between the piston pin 25 and the small end hole 29, thereby improving the reliability. And higher efficiency is achieved.

  Further, in a hermetic compressor adopting a reciprocating type compression mechanism, a cylinder block 14 that forms a compression chamber 15 having a cylindrical inner diameter, and a piston 23 that has a cylindrical outer diameter that reciprocates in the compression chamber 15; The piston 23 is provided with a connecting rod 26 for connecting the eccentric shaft portion 12 of the shaft 10 via the piston pin 25, and the shaft 10 is fixed to the shaft center of the rotor 3 of the electric motor portion. Is known which operates a compression mechanism.

  In such a hermetic compressor, a gap is required for sliding between the inner diameter of the compression chamber 15 and the outer diameter of the piston 23 that reciprocates. If the gap is large, the compression is performed in the compression chamber 15. Blow-by in which high-temperature and high-pressure refrigerant gas leaks occurs to reduce the compression efficiency. If this gap is reduced, the sliding loss increases and the compression efficiency decreases.

  Therefore, a hermetic compressor using a compression chamber 15 formed so that the inner diameter increases from the side where the piston 23 is located at the top dead center toward the side located at the bottom dead center has been proposed.

  10 (a) and 10 (b) are cross-sectional views of the compression portion of the hermetic compressor disclosed in Patent Document 2 below, and FIG. 10 (a) shows a state where the piston 23 is at the bottom dead center. FIG. 10B shows a state where the piston 23 is at the top dead center.

  In FIGS. 10A and 10B, a connecting rod 26 is connected to a piston 23 inserted in a compression chamber 15 provided in the cylinder block 14 so as to be reciprocally movable through a piston pin 25. The connecting rod 26 reciprocates the piston 23 between the bottom dead center position shown in FIG. 10 (a) and the top dead center position shown in FIG. 10 (b) by the eccentric movement of the eccentric shaft portion of the shaft (not shown). To drive.

  A valve plate (not shown) is mounted on the opposite end surface of the compression chamber 15 when viewed from the connecting rod 26, and the compression chamber 15 is formed by the piston 23, the cylinder block 14 and the valve plate.

  The compression chamber 15 is formed so as to have a tapered portion 17 in which the inner diameter increases from Dt to Db (> Dt) from the side where the piston 23 is located at the top dead center toward the side located at the bottom dead center. The piston 23 has the same outer diameter dimension over the entire length.

  By this combination, the pressure in the compression chamber 15 increases so much from the bottom dead center position shown in FIG. 10A until the piston 23 is moving to the top dead center side in the compression stroke for compressing the refrigerant gas. Therefore, even if the gap is relatively large, the blow-by that is the leakage of the refrigerant gas hardly occurs due to the sealing effect by the lubricating oil 6, and the sliding resistance of the piston 23 is small.

  When the compression stroke further proceeds and the pressure of the refrigerant gas in the compression chamber 15 gradually increases and the piston 23 is close to the top dead center position shown in FIG. Although the pressure rises to a pressure and blow-by is likely to occur, the gap becomes smaller on the top dead center side, so that the sealing effect by the lubricating oil 6 can be obtained and the occurrence of blow-by can be reduced.

  FIG. 11 is a cross-sectional view of a compression portion capable of refrigerant compression disclosed in Patent Document 3 below, and the same elements as those in FIGS. Omitted.

  Here, the compression chamber 15 includes a tapered portion 17 whose inner diameter increases from Dt to Db (> Dt) from the side where the piston 23 is located at the top dead center to the side located at the bottom dead center, and the top dead center. The piston 23 is formed so as to have a straight portion 18 in which the inner diameter dimension is constant in the axial direction only in the section of the length L at a position corresponding to the end portion of the piston 23 near the point on the compression chamber 15 side. Have the same outer diameter over the entire length.

By this combination, blow-by hardly occurs and the sliding resistance of the piston 23 is reduced until the state in the middle of shifting to the top dead center side in the compression stroke, and the sliding resistance of the piston 23 is further reduced and the piston 23 is moved to the top dead center position. In the state where they are close to each other, it is possible to reduce the occurrence of refrigerant gas leakage accompanying an increase in gas pressure, compared to the case where the tapered portion 17 is formed over the entire length.
JP 09-317644 A JP 2002-89450 A Japanese National Patent Publication No. 7-550833

  However, in the conventional hermetic compressor described above, it is insufficient to prevent the twist between the piston 23 and the inner wall 15a of the compression chamber 15 generated when a compression load for compressing the refrigerant gas is applied. .

  Using the cross-sectional view of the main part shown in FIG. 9, it will be described that a twist occurs between the piston 23 and the inner wall 15 a of the compression chamber 15.

  As shown in FIG. 9, a compression load F generated in the piston 23 in the compression stroke of the refrigerant gas acts on the eccentric shaft portion 12 via the connecting rod 26. When the compressive load F acts on the eccentric shaft portion 12, there is a clearance between the main shaft portion 11 and the bearing portion 20, so that the shaft 10 has a main shaft portion within the bearing portion 20 with respect to the shaft center of the bearing portion 20. 11 is tilted to the maximum, and the eccentric shaft portion 12 is also tilted with respect to the shaft center of the main shaft portion 11, and the relative angle of the shaft center between the compression chamber 15 and the bearing portion 20 is inclined. Also changes.

  Therefore, the axis of the piston 23 is inclined as shown in FIG.

  The above-described conventional hermetic compressor suppresses the inclination of the piston 23 by making the inner wall of the small-end hole portion 29 convex, but causes a twist between the piston 23 and the inner wall 15a of the compression chamber 15. I couldn't prevent it.

  Part of the sliding surface on which the piston 23 slides with the inner wall 15a of the compression chamber 15 due to the occurrence of a twist between the piston 23 and the inner wall 15a of the compression chamber 15, that is, the edge of the upper end surface indicated by p in the figure The surface pressure of a part of is increased locally. For this reason, even with the conventional hermetic compressor in which the inner wall of the small end hole 29 is convex, the piston 23 wears quickly, the wear amount increases, and the sliding loss increases. Had problems that had to be done.

  Further, in the compression portion having the conventional configuration disclosed in Patent Documents 2 and 3, even when the piston 23 returns to the bottom dead center position, the entire piston 23 is accommodated in the cylindrical hole portion 16 of the compression chamber 15. Therefore, there is a problem that the lubricating oil 6 is not sufficiently supplied between the cylindrical hole 16 and the piston 23 that require lubrication.

  Further, the lubricating oil 6 is pushed out when the piston 23 is close to the top dead center position and the gap becomes small, and then the lubricating oil 6 is sealed when the gap becomes large at the bottom dead center position. Therefore, there is a problem that it is difficult to suppress the occurrence of blow-by and the sliding resistance increases due to the lack of the lubricating oil 6.

  The present invention solves the above-mentioned problems, and prevents wear of the piston by preventing the occurrence of twisting between the piston and the compression chamber, reduces sliding loss, and further increases reliability. It is an object of the present invention to provide a hermetic compressor that can achieve high efficiency and high efficiency.

  Furthermore, the present invention solves the above problems, and provides a hermetic compressor that can achieve high efficiency by supplying more lubricating oil between the cylinder block and the piston. The purpose is to do.

  In order to solve the above-described conventional problems, the present invention provides a first center line indicating the axis of the bearing portion or a third center line parallel to the first center line and a second center indicating the axis of the compression chamber. The bearing portion and the compression chamber are arranged so as to intersect with each other, and when the angle between the first center line or the third center line and the second center line is α, the following (Equation 1 Α is a design value of the angle of the axial center of the compression chamber, and the compression chamber has an inner diameter that increases from the side where the piston is located at the top dead center toward the side where the piston is located at the bottom dead center. The angle between the shaft center of the piston and the shaft center of the compression chamber when the outer peripheral surface of the piston slides along the taper portion is δ, and the clearance between the bearing portion and the main shaft portion When the absolute value of the inclination of the shaft with respect to the bearing portion based on γ is γ, δ and γ satisfy the following (Equation 2): Are as hereinbefore, it has the effect of preventing prying between piston and the compression chamber.

  The hermetic compressor according to the present invention includes a first center line indicating the axis of the bearing portion or a third center line parallel to the first center line and a second center line indicating the axis of the compression chamber. The bearing portion and the compression chamber are arranged so as to cross each other, and when the angle formed by the first center line or the third center line and the second center line is α, Α is the design value of the angle of the axial center of the compression chamber, and the compression chamber is formed so that the inner diameter dimension increases from the side where the piston is located at the top dead center toward the side where the piston is located at the bottom dead center. Bearing part based on the clearance between the bearing part and the main shaft part, where δ is the angle between the axial center of the piston and the axial center of the compression chamber when the outer peripheral surface of the piston slides along the tapered part. When the absolute value of the inclination of the shaft with respect to γ is γ, δ and γ satisfy the above (Equation 2). Prying between piston and the compression chamber can be prevented, thereby, a high reliability due to wear reduction of the piston, and higher efficiency due to sliding loss mitigation is achieved.

The invention according to claim 1 is a hermetic compressor in which an electric element and a compression element adopting a reciprocating cantilever bearing driven by the electric element are accommodated in an airtight container, wherein the compression element is A shaft having a main shaft portion that is rotationally driven by the electric element, a shaft having an eccentric shaft portion that is formed so as to move integrally with the main shaft portion at one end of the main shaft portion, and by supporting the main shaft portion of the shaft. A bearing portion that forms a cantilever bearing, a cylinder block that is arranged to be fixed at a fixed position with respect to the bearing portion, and that forms a substantially cylindrical compression chamber, and reciprocates within the compression chamber A piston inserted in a possible manner, and a connecting rod connecting the eccentric shaft portion and the piston, and a first center line indicating the shaft center of the bearing portion or a third center line parallel to the first center line Centerline and front The bearing portion and the compression chamber are arranged so that a second center line indicating the axis of the compression chamber intersects with each other, and the first center line or the third center line and the second center line are arranged. Where α is the design value of the angle of the axial center of the compression chamber, and the compression chamber is subjected to a compression load for compressing the refrigerant gas. In order to prevent the piston from being twisted with respect to the compression chamber due to the inclination of the shaft, the inner diameter dimension is increased from the side where the piston is located at the top dead center toward the side located at the bottom dead center. A taper portion formed to correspond to an inclination of the axial center of the piston, and an axial center of the piston and an axial center of the compression chamber when the outer peripheral surface of the piston slides along the tapered portion; And the bearing part and the main shaft part When the absolute value of the inclination of the shaft relative to the bearing portion based on the clearance is γ, the relationship between δ and γ satisfies the following (Equation 2), and the twist between the piston and the compression chamber is Accordingly, high reliability by reducing wear of the piston and high efficiency by reducing sliding loss can be achieved.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the piston is located at the top dead center, the piston is formed adjacent to the tapered portion at a position corresponding to the upper end portion of the piston on the compression chamber side. In addition to the effect of the invention according to claim 1, it is possible to prevent blow-by in which high-pressure gas leaks from the gap between the piston and the compression chamber, and to achieve high refrigeration capacity. .

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein δ and γ satisfy the following (Equation 3), and the twist between the piston and the compression chamber is further reduced. In addition to the effects of the invention described in claim 1 or 2, it is possible to achieve higher reliability by reducing piston wear and higher efficiency by reducing sliding loss. .

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, when the piston is located at a bottom dead center, at least a part of the piston is exposed from the cylinder block. 4. In addition to the effect of the invention according to any one of claims 1 to 3, the reliability can be further improved by reducing the wear of the piston. In addition, high efficiency can be achieved by reducing sliding loss.

  The invention according to claim 5 is equipped with the hermetic compressor according to any one of claims 1 to 4, and can provide a highly efficient refrigeration apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a hermetic compressor according to the first embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part when the compressive load does not act in the same embodiment, and FIG. 3 is the same embodiment. 4 is an enlarged cross-sectional view of the main part when the compression load is applied, FIG. 4 is a cross-sectional view of the main part showing the positional relationship between the bearing part and the compression chamber in the same embodiment, and FIG. 5 is based on the same embodiment. It is a characteristic view which shows the result of the experiment done.

  In FIG. 1 to FIG. 3, an electric element 104 including a stator 102 and a rotor 103 and a compression element 105 driven by the electric element 104 are accommodated in an airtight container 101. Lubricating oil 106 is stored at the bottom of the inside.

  The shaft 110 has a main shaft portion 111 and an eccentric shaft portion 112 formed eccentrically at one end so as to move integrally with the main shaft portion 111, and of these, the main shaft portion 111 is located at the axis of the rotor 103. It is fixed. An oil supply passage 113 is provided inside or on the surface of the shaft 110, and a lower end portion of the shaft 110 extends so that the lubricating oil 106 enters the oil supply passage 113 to a predetermined depth.

  Here, the cylindrical hole portion 116 provided in the cylinder block 114 so as to form the compression chamber 115 together with the piston 123 and the valve plate 150 is formed from the side where the piston 123 is located at the top dead center as shown in FIG. A taper portion 117 whose inner diameter increases from Dt to Db (> Dt) toward the bottom dead center side, and a position corresponding to the end portion on the compression chamber 115 side of the piston 123 reaching the top dead center. In addition, the section having the length L is formed so as to have a straight portion 118 whose inner diameter dimension is constant in the axial direction, and the piston 123 has the same outer diameter dimension over the entire length.

  The cylinder block 114 includes a substantially cylindrical compression chamber 115 and a bearing portion 120 arranged so as to be fixed to each other at a fixed position. The bearing portion 120 is on the side of the eccentric shaft portion 112 in the main shaft portion 111 of the shaft 110. A cantilever bearing is formed by pivotally supporting the end of the shaft.

  A piston 123 is inserted into the compression chamber 115 so as to reciprocate. A piston pin 125 is attached to the piston 123 so as to be parallel to the eccentric shaft portion 112.

  As shown in FIGS. 2 and 3, the connecting rod 126 includes a large end hole portion 128, a small end hole portion 129, and a rod portion 130, and the large end hole portion 128 is fitted to the eccentric shaft portion 112. The small end hole portion 129 is connected to the piston 123 via the piston pin 125, whereby the eccentric shaft portion 112 and the piston 123 are connected.

  The difference between the first embodiment and the conventional hermetic compressor shown in FIG. 7 is that when a compression load for compressing refrigerant gas is applied, the axis C of the piston 123 is also inclined due to the inclination of the shaft 110. However, the tapered portion 117 is formed in the cylindrical hole portion 116 that forms the compression chamber 115 in accordance with the inclination of the piston 123.

  Since the inclination of the shaft center C and the state of the taper portion 117 cannot be sufficiently expressed only by FIG. 1, the shaft center C is not inclined with respect to the compression chamber 115 in which the taper portion 117 is formed when the compression load does not act. The state of the piston 123 is shown in the enlarged cross-sectional view of FIG. 2, and when the compressive load is applied, the state of the piston 123 tilted so that the tapered portion 117 of the compression chamber 115 and the shaft center C coincide with each other is shown in the enlarged cross-sectional view of FIG. Is shown.

  As for the tapered portion 117 of the compression chamber 115, as shown in FIG. 4, a first center line 141 indicating the axis of the bearing portion 120 and a second center line 142 indicating the axis of the compression chamber 115 are mutually connected. The bearing portion 120 and the compression chamber 115 are arranged so as to intersect with each other, and the angle α formed by the first center line 141 and the second center line 142 is the above (Equation 1).

  The operation and action of the hermetic compressor configured as described above will be described below.

  The rotor 103 of the electric element 104 rotates the shaft 110, and the rotational movement of the eccentric shaft portion 112 is transmitted to the piston 123 via the connecting rod 126, whereby the piston 123 reciprocates in the compression chamber 115. Due to the reciprocating motion of the piston 123, the refrigerant gas is sucked into the compression chamber 115 from the cooling system (not shown), compressed, and then discharged to the cooling system again.

  The lower end portion of the oil supply passage 113 is pumped by the rotation of the shaft 110, and by this pump action, the lubricating oil 106 at the bottom of the sealed container 101 is pumped upward through the oil supply passage 113. Then, it scatters horizontally in the entire circumferential direction in the sealed container 101 and is supplied to the piston pin 125, the piston 123, and the like for lubrication.

  In the cantilever bearing, the compression load when compressing the refrigerant gas is supported only by the main shaft portion 111 on one side with respect to the eccentric shaft portion 112 of the shaft 110, so that the shaft 110 has a clearance between the main shaft portion 111 and the bearing portion 120. Tilt inside.

  Therefore, the relative angle between the axial center 144 of the main shaft portion 111 of the shaft 110 inclined within the clearance of the bearing portion 120 and the second center line 142 indicating the axial center of the compression chamber 115 is π / 2 [rad]. Becomes smaller.

  In order to prevent the piston 123 from being twisted with respect to the compression chamber 115 due to the inclination of the shaft 110, in the present embodiment, a tapered portion 117 is formed in the cylindrical hole portion 116 corresponding to the inclination of the axis C of the piston 123. ing.

  In FIG. 4, the intersection of the first center line 141 indicating the axis of the bearing 120 and the second center line 142 indicating the axis of the compression chamber 115 is defined as O, and the clearance between the bearing 120 and the main shaft 111 is defined as O. The absolute value of the inclination of the shaft 110 with respect to the bearing portion 120 based on this is γ, and the shaft center of the piston 123 and the shaft center of the compression chamber 115 when the outer peripheral surface of the piston 123 slides along the taper portion 117 are shown. 2 is the angle δ between the taper portion 117 and the second center line 142, and the angle of the compression chamber 115 is such that the value satisfies the above (Equation 2). A portion 117 is formed.

  An experimental value can be adopted as a specific value relating the angle δ formed between the second center line 142 indicating the axis of the compression chamber 115 and the tapered portion 117 to the absolute value γ of the inclination of the shaft 110. FIG. 5 shows several types of cylinder blocks 114 in which the angle δ formed by the second center line 142 indicating the axis of the compression chamber 115 and the tapered portion 117 is changed, and a hermetic compressor in which these cylinder blocks 114 are incorporated. It is the result of measuring efficiency.

  In other words, the angle δ of the tapered portion 117 with respect to the first center line 141 indicating the axis of the bearing 120 and the expansion of the second center line 142 indicating the axis of the compression chamber 115 from π / 2 is the inclination of the shaft 110. FIG. 6 is a characteristic diagram in which each measurement value is approximated by a quadratic curve with the dimensionless number divided by the absolute value γ taken along the horizontal axis and the efficiency COP for each angle as the vertical axis.

Here, the efficiency when the value of the horizontal axis is zero indicates the average value of the conventional hermetic compressor, and the absolute value γ of the inclination of the shaft 110 due to the clearance in this experiment is about 3.7 × 10 ^−4. [Rad].

  From FIG. 5, the efficiency is highest when the value of δ / γ is in the range of about 1 to 2.7 (A), and the value of δ / γ is in the range of about 0.5 to 3.3 (B). It can be seen that the efficiency is higher than that of the hermetic type compressor.

  Therefore, when the angle of the second center line 142 indicating the axis of the compression chamber 115 with respect to the first center line 141 indicating the axis of the bearing portion 120 is α represented by the above (Equation 1), δ and It is concluded that γ preferably satisfies the above (Equation 2), and it is optimal that δ and γ satisfy the above (Equation 3).

  As described above, α represented by the above (Equation 1) is the design value of the angle of the axial center of the compression chamber 115, and the angle formed by the second center line 142 indicating the axial center of the compression chamber 115 and the tapered portion 117. By determining δ so as to be close to the actual value in association with the absolute value γ of the inclination of the shaft 110 with respect to the bearing portion 120, it is possible to prevent the twist between the piston 123 and the compression chamber 115.

Note that α, which is an angle of the second center line 142 indicating the axis of the compression chamber 115 with respect to the first center line 141 indicating the axis of the bearing 120, is basically π / 2 [rad]. According to the experiment, when α is in the range of (−1 × 10 ⁻³ + π / 2) to (1 × 10 ⁻³ + π / 2) [rad], as described above, δ and γ are the above ( As a result, it is optimal that the relationship satisfying Equation (2) is satisfied and that δ and γ satisfy the above Equation (3).

  In order to increase efficiency, the second center line 142 indicating the axis of the compression chamber 115 and the first center line 141 indicating the bearing portion 120 may be arranged so as not to intersect each other.

  Concretely, it demonstrates with reference to sectional drawing of the upper surface which shows the positional relationship of the bearing part and compression chamber in the same embodiment of FIG.

  The first center line 141 (pointed in FIG. 6) indicating the bearing portion 120 is displaced in parallel by the e dimension with respect to the second center line 142 indicating the axis of the compression chamber 115, and generally, the offset and It is a configuration called.

  In the above configuration, the third center line 143 (pointed in FIG. 6) parallel to the first center line 141 (pointed in FIG. 6) indicating the axis of the bearing portion 120 and the axis of the compression chamber 115 are arranged. 5 and the second center line 142, and the e dimension is within 3 mm, the same result as the test result shown in FIG. 5 is obtained also in this configuration.

  Therefore, if the offset of the compression chamber 115 with respect to the bearing portion 120 is within 3 mm (e dimension), the same effect can be obtained, and the first center line 141 or the first center indicating the axis of the bearing portion 120 is obtained. The bearing portion 120 and the compression chamber 115 are arranged so that a third center line parallel to the line 141 intersects with each other, and the first center line 141 or the third center line 143 and the second center line 142 are When the angle formed is α ′ represented by the following (Equation 4), it is preferable that δ and γ satisfy the above (Equation 2), and δ and γ satisfy the above (Equation 3). It is concluded that it is optimal to have a relationship that

  In the embodiment of the present invention, a straight portion 118 whose inner diameter is constant in the axial direction is provided on the top dead center side of the compression chamber 115, and further, on the connecting rod 126 side of the compression chamber 115 from the top dead center side to the bottom dead center side. A tapered portion 117 is provided so that the inner diameter dimension increases toward the side.

  As a result, blow-by hardly occurs up to the middle of the transition to the top dead center side in the compression stroke, the sliding resistance (sliding loss) of the piston 123 is reduced, the compression stroke is further advanced, and the piston 123 is moved upward. In the state close to the dead center position, it is considered that the occurrence of gas leakage of the refrigerant gas accompanying the increase in gas pressure can be reduced as compared with the case where the tapered portion 117 is formed over the entire length.

  Further, in the cantilever bearing of the present embodiment, when the piston 123 is located at the bottom dead center, at least a part of the piston 123 is formed to be exposed from the cylinder block 114. Specifically, the piston 123 1/3 or more of the total length in the axial direction is exposed.

  When the piston 123 is located at the bottom dead center where the compression load caused by the pressure of the refrigerant gas does not act so much, at least 1/3 or more of the total length in the axial direction of the piston 123 is exposed. It is possible to supply oil directly to the part, and it is possible to achieve high reliability by reducing wear of the piston 123 and high efficiency by reducing sliding loss.

  As described above, since the hermetic compressor according to the present invention can achieve high reliability and high efficiency, it is used for an apparatus using a refrigeration cycle such as an air conditioner or a vending machine. The present invention can be widely applied to hermetic compressors.

1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. The expanded sectional view of the principal part when the compressive load does not act in the embodiment The expanded sectional view of the principal part when the compressive load acts in the embodiment Sectional drawing of the principal part which shows the positional relationship of the bearing part and compression chamber in the embodiment Characteristic diagram showing the results of experiments conducted based on the same embodiment Sectional drawing of the upper surface which shows the positional relationship of the bearing part and compression chamber in the embodiment Vertical section of a conventional hermetic compressor 7 is an enlarged cross-sectional view of the main part of FIG. Sectional drawing of the principal part of FIG. Sectional view of the compression part of another conventional hermetic compressor Sectional drawing of the compression part in which the other conventional refrigerant compression is possible

DESCRIPTION OF SYMBOLS 101 Airtight container 104 Electric element 105 Compression element 110 Shaft 111 Main shaft part 112 Eccentric shaft part 114 Cylinder block 115 Compression chamber 117 Taper part 118 Straight part 120 Bearing part 123 Piston 125 Piston pin 126 Connecting rod 141 First center line 142 2nd Center line 143 Third center line

Claims (5)

A hermetic compressor in which an electric element and a compression element adopting a reciprocating cantilever bearing driven by the electric element are housed in a hermetic container, wherein the compression element is rotationally driven by the electric element A shaft having an eccentric shaft portion formed so as to move integrally with the main shaft portion at one end of the main shaft portion and the main shaft portion; and a bearing portion that forms a cantilever bearing by supporting the main shaft portion of the shaft. A cylinder block which is arranged so as to be fixed at a fixed position with respect to the bearing portion and forms a substantially cylindrical compression chamber; and a piston which is inserted in the compression chamber so as to be reciprocally movable; A connecting rod for connecting the eccentric shaft portion and the piston, and a first center line indicating the shaft center of the bearing portion or a third center line parallel to the first center line and a shaft of the compression chamber Second to show heart When the bearing portion and the compression chamber are arranged so that a center line intersects each other, and an angle between the first center line or the third center line and the second center line is α, The α expressed by the following (Equation 1) is a design value of the angle of the axial center of the compression chamber, and the compression chamber is subjected to a compression load that compresses the refrigerant gas, and the piston due to the inclination of the shaft. In order to prevent the piston from being twisted with respect to the compression chamber, the inner diameter of the piston increases from the side where the piston is located at the top dead center to the side where the piston is located at the bottom dead center. has a tapered portion formed Te, the angle between the axis of the shaft center and the compression chamber of the piston when the sliding outer peripheral surface along said piston and δ in the tapered portion, the bearing portion And before based on the clearance of the main shaft When the absolute value of the slope of the shaft relative to the bearing unit is gamma, the hermetic compressor in relation to the said [delta] gamma to satisfy the following equation (2).
The hermetic compressor according to claim 1, further comprising a straight portion formed adjacent to the taper portion at a position corresponding to an upper end portion of the piston on the compression chamber side when the piston is located at a top dead center. 3. The hermetic compressor according to claim 1, wherein δ and γ satisfy the following relationship (Equation 3).
  The hermetic compressor according to any one of claims 1 to 3, wherein at least a part of the piston is exposed from the cylinder block when the piston is located at a bottom dead center.   A refrigeration apparatus equipped with the hermetic compressor according to any one of claims 1 to 4.