JP2020037887A - Hermetic electric compressor - Google Patents

Abstract

To provide a hermetic electric compressor which is improved in oil supply performance, and high in the reliability of wear resistance.SOLUTION: This hermetic electric compressor C comprises an electric motor D, a crankshaft 5, a compression mechanism part K having a main bearing 6 and a sub-bearing 10, and lubricated with a lubricant on a slide face, and an accommodation part 1 for accommodating the electric motor D and the compression mechanism part K. The main bearing 6 and the sub-bearing 10 have substantially-spiral grooves 6r, 10r for transporting the lubricant to a direction of the main bearing 6 from the sub-bearing 10 by the rotation of the crankshaft 5 at the crankshaft 5 sides or bearing sides of the main bearing 6 and the sub-bearing 10. When setting cross sections of the substantially-spiral grooves 6r, 10r as A, A, setting shaft diameters as D, D, and setting angles of the substantially-spiral grooves 6r, 10r with respect to horizontality in a rotation direction of the crankshaft 5 as θ, θ, a relationship of A×D×cosθ≤A×D×cosθis established.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hermetic electric compressor.

  2. Description of the Related Art Conventionally, as a method of lubricating a pump in a hermetic electric compressor, there is a method using a viscous pump provided with a lubrication groove on a shaft outer circumference or a bearing inner circumference. In the viscous pump, the oil stored in the bottom of the closed vessel is caused to flow through the sub-shaft portion, the crankshaft eccentric portion, and the main shaft portion by virtue of its viscosity as the shaft rotates. As a result, each bearing portion is lubricated, and the reliability of wear resistance is improved.

  The hermetic electric compressor described in Patent Literature 1 has an oil supply groove on the outer peripheral surface of the shaft, one end of which communicates with the oil reservoir, and the other end of which opens to the space inside the closed container. The oil supply groove has a substantially helical shape in a direction in which oil is conveyed to the space inside the closed container when the shaft rotates in at least one of the main bearing portion, the sub bearing portion, and the eccentric portion of the crankshaft. Further, the sectional area of the oil supply groove of the main bearing portion on the downstream side of the oil supply is smaller than the sectional area of the oil supply groove of the auxiliary bearing portion on the upstream side of the oil supply.

  In the hermetic electric compressor described in Patent Document 1, the sectional area of the oil supply groove is set so that the upstream sub-bearing portion is larger than the downstream main bearing portion. Therefore, the flow path of the oil in the oil supply groove on the upstream side can be enlarged, and even after a part of the oil passing through the oil supply groove in the sub-bearing portion is supplied into the compression chamber by the pressure difference from the upper and lower surfaces of the rollers, the oil on the downstream side can be obtained. The oil groove in the main bearing can be easily sealed with oil.

JP 2000-291578 A

By the way, in the configuration of Patent Literature 1, since the cross-sectional area of the oil supply groove of the sub-bearing portion is larger than that of the main bearing portion, it is possible to easily supply more oil to the sub-bearing portion. In a variety of hermetic electric compressors with different bearing shaft diameters and substantially spiral pitches of the oil supply grooves, the oil supply grooves in the sub-bearing can be larger than the main bearing, but the main bearing in the downstream side There was a concern that the refueling volume would not increase.

  Further, the configuration described in FIG. 1 of Patent Document 1 can increase the amount of lubrication of the sub-bearing portion relative to the main bearing portion, but is smaller than the eccentric portion of the crankshaft. For this reason, there is a concern that when the pressure is reduced in the oil supply groove of the sub-bearing portion, the refrigerant dissolved in the oil foams and the bearing portions cannot be sealed with the oil, thereby lowering the reliability of each bearing portion.

  The present invention has been made in view of the above situation, and has an object to provide a hermetic electric compressor in which the auxiliary bearing portion, the crankshaft eccentric portion, and the main bearing portion have improved lubricating properties and have high wear resistance. I do.

In order to solve the above problems, a hermetic electric compressor according to a first aspect of the present invention includes an electric motor, a crankshaft that is driven to rotate by the electric motor, and a main bearing and an auxiliary bearing that support the crankshaft. A compression mechanism portion in which a shaft and a sliding surface of the main bearing and the sub-bearing are lubricated with lubricating oil, and a housing portion that houses the electric motor and the compression mechanism portion, wherein the main bearing and the sub-bearing are A rotation of the crankshaft, in the direction from the sub-bearing to the main bearing, a substantially helical groove for conveying the lubricating oil on the crankshaft side or the bearing side of the main bearing and the sub-bearing. , The cross-sectional areas of the substantially helical grooves of the main bearing and the sub-bearing are A ₁ and A ₂ , the shaft diameters are D ₁ and D ₂ , and the substantially helical grooves are horizontal to the rotation direction of the crankshaft. Let the angles be θ ₁ and θ ₂ Relationship when
A ₁ × D ₁ × cos θ ₁ ≦ A ₂ × D ₂ × cos θ ₂
Here, the grooves provided in the main bearing and the sub-bearing satisfy 0 ° <θ ₁ , θ ₂ <90 ° when the horizontal in the rotation direction is 0 °, and the grooves provided in the crankshaft are When the horizontal in the rotation direction is set to 0 °, they are formed so as to satisfy −90 ° <θ ₁ and θ ₂ <0 °.

  ADVANTAGE OF THE INVENTION According to this invention, the lubrication property of a sub-bearing part, a crankshaft eccentric part, and a main bearing part is improved, and the hermetic electric compressor with high reliability of abrasion resistance can be provided.

1 is a longitudinal sectional view of an electric compressor according to a first embodiment of the present invention. (A) is a longitudinal sectional view of an auxiliary bearing, (b) is a developed view of an inner peripheral surface of the auxiliary bearing, and (c) is an AA sectional view of (a). (A) is a longitudinal sectional view of a main bearing, (b) is a developed view of an inner peripheral surface of the main bearing, and (c) is a BB sectional view of (a). The external view of a crankshaft. FIG. 6 is a vertical sectional view of the electric compressor according to the second embodiment. FIG. 7 is a vertical sectional view of a hermetic electric compressor according to a third embodiment. (A) shows a spiral groove viewed from the center side of a crankshaft of a hermetic electric compressor according to a modification of the third embodiment, (b) is an enlarged view of the spiral groove of (a), and (c) is an embodiment. Sectional drawing which shows the spiral groove seen from the center side of the auxiliary bearing of the compressor of form 3, (d) is an enlarged view of the spiral groove of (c). FIG. 10 is a longitudinal sectional view of a hermetic electric compressor according to a fourth embodiment. (A), (b), (c) is a sectional view of a main bearing, a sectional view of a sub-bearing, and an external view of a crankshaft of a fourth embodiment, respectively. FIG. 5 is a longitudinal sectional view of a hermetic electric compressor according to a fifth embodiment and a modification. (A) is a longitudinal sectional view of a main bearing, (b) is a longitudinal sectional view of an auxiliary bearing. (A) is an external view of the crankshaft of the hermetic electric compressor of the modification of Embodiment 5, (b) is a CC sectional view of (a), and (c) is a developed view of an eccentric portion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

<< First Embodiment >>
FIG. 1 shows a longitudinal sectional view of an electric compressor C of Embodiment 1 according to the present invention.
In the hermetic electric compressor C according to the first embodiment, an electric element D and a compression mechanism K are contained in a hermetic container 1.

  The compression mechanism K is connected to the electric element D by the crankshaft 5. In the compression mechanism K, a compression chamber for compressing the gas refrigerant is formed by reducing the internal volume.

The closed container 1 includes a cylinder 1A, a lid 1B, and a bottom 1C. A closed space is formed inside the closed container 1.
The cylindrical body 1A is formed of a steel plate into a cylindrical shape with upper and lower openings. The lid 1B forms a top plate. The bottom body 1C forms a bottom plate.
The lid 1B and the bottom 1C are fitted and welded to the cylindrical body 1A to seal the inside.

The electric element D constitutes a drive source of the compressor C. The electric element D includes a stator 3 fixed to the closed casing 1 by shrink fitting or the like, and a rotor 4 to which a crankshaft 5 is fitted.
The compression mechanism K compresses the sucked gas refrigerant (arrow α1 in FIG. 1) to increase the pressure to the target pressure.

The compression mechanism portion K is configured with the main bearing 6, the crankshaft 5, the auxiliary bearing 10, the cylinder 7, the roller 11, and the vane 13 as main elements.
The crankshaft 5 has a main bearing insertion portion 20 that is inserted into the main bearing 6 on one side, and an auxiliary bearing insertion portion 21 that is inserted into the auxiliary bearing 10 on the other side. The crankshaft 5 is rotatably supported on the closed casing 1 by a main bearing 6 and a sub-bearing 10.

  The crankshaft 5 is formed integrally with an eccentric portion 5h whose center of gravity is eccentric at a position different from the rotation center O between the main bearing insertion portion 20 and the sub bearing insertion portion 21. The roller 11 is rotatably fitted into the eccentric portion 5h. The roller 11 revolves by the eccentric rotation of the eccentric portion 5h.

The cylinder 7 is a cylindrical member in which a gas refrigerant suction chamber and a compression chamber are formed between the cylinder 7 and the outer peripheral surface 11 g of the roller 11.
The vane 13 is fitted to the cylinder 7 so as to contact the outer peripheral surface 11g of the roller 11 disposed inside the cylinder 7. The vane 13 is pressed against the outer peripheral surface 11g of the roller 11 by a spring 13a. The gap between the outer peripheral surface 11g of the roller 11 and the vane 13 is sealed by an oil film. Due to the rotational movement of the eccentric portion 5h, the suction chamber for sucking the gas refrigerant and the compression chamber for increasing the sucked gas refrigerant to the discharge pressure are surrounded by the outer peripheral surface 11g of the roller 11 in the cylinder 7, the vane 13, and the cylinder 7. Formed in space.

  Above and below the compression mechanism K in the axial direction, a main bearing fitting portion 20 and a sub bearing fitting portion 21 which are parts of the crankshaft 5 are arranged. The crankshaft 5 is rotatably supported in the closed casing 1 by fitting the main bearing fitting portion 20 and the sub bearing fitting portion 21 into the main bearing 6 and the sub bearing 10 respectively. A main bearing 6 is fixed to one end face of the cylinder 7 (an upper end face of the cylinder 7 in FIG. 1), and a sub-bearing 10 is fixed to the other end face of the cylinder 7 (a lower end face of the cylinder 7 in FIG. 1). Have been.

  A required amount of refrigerating machine oil (not shown) is sealed inside the bottom 1C of the closed container 1. The refrigerating machine oil operates the mechanical elements in the closed container 1 smoothly and forms an oil film at a place where a seal is required to seal.

<Operation of the electric compressor C>
The accumulator 2 separates the refrigerant into gas and liquid.
During operation of the electric compressor C (hereinafter, referred to as the compressor C), the gas refrigerant flows into the compression mechanism K through the accumulator 2 (arrow α1 in FIG. 1). The inflowing gas refrigerant is discharged into the closed container 1 after being compressed by the compression mechanism K. Thus, the inside of the closed container 1 is filled with the discharge pressure of the gas refrigerant discharged from the compression mechanism K. Thereafter, the compressed gas refrigerant is discharged to the outside of the sealed container 1 through the discharge pipe 17 (arrow α2 in FIG. 1).

  Further, the refrigerating machine oil in the bottom body 1 </ b> C of the closed container 1 is supplied through the oil supply passage 5 </ b> B of the crankshaft 5.

<Lubrication of compression mechanism K>
2A is a longitudinal sectional view of the auxiliary bearing 10, FIG. 2B is a developed view of the inner peripheral surface 10n of the auxiliary bearing 10, and FIG. 2C is FIG. It is AA sectional drawing of.

3A is a longitudinal sectional view of the main bearing 6, FIG. 3B is a developed view of the inner peripheral surface 6n of the main bearing 6, and FIG. 3C is FIG. FIG.
2 (a) to 2 (c) and 3 (a) to 3 (c) show a case where the crankshaft 5 rotates counterclockwise when viewed from above. Therefore, when the crankshaft 5 rotates clockwise, the inclinations of the spiral grooves 10r and 6r are opposite to those in FIGS. 2 (a) to 2 (c) and FIGS. 3 (a) to 3 (c).

FIG. 4 is an external view of the crankshaft 5.
As shown in FIGS. 2 (a) and 3 (a) (see also FIG. 1), the compressor C has a spiral groove 10r having a substantially spiral shape in a direction of conveying oil from the auxiliary bearing 10 to the main bearing 6. 6r are provided. That is, in the electric compressor C, as shown in FIG. 2A, a spiral groove 10r having a substantially spiral shape for conveying oil is provided on the inner peripheral surface 10n of the auxiliary bearing 10. As shown in FIG. 3A, a spiral groove 6r having a substantially spiral shape for conveying oil is provided on the inner peripheral surface 6n of the main bearing 6.

A description will be given of a viscous pump that is an oiling system using the spiral groove 6r of the main bearing 6 from the spiral groove 10r of the auxiliary bearing 10.
The lubrication amount Q [mm ³ / min] per unit time (min) by the viscous pump using the spiral grooves 10r and 6r is the crankshaft diameter D [mm], the crankshaft rotation speed N [min ⁻¹ ], the spiral groove Using the cross-sectional area A [mm ² ] and the angle θ [degrees] (0 <θ <90 degrees) with respect to the horizontal direction (the plane perpendicular to the rotation axis) of the spiral groove, the following expression (1) can be obtained. Can be.

Q = A × π × (D / 2) × N × cos θ (1)
The oil supply to the compressor chamber and the bearings (10, 6) by the spiral grooves 10r, 6r of the compressor C is performed as follows.

  Oil accumulated in the bottom body 1C at the bottom of the closed casing 1 is circulated to the upper part of the sub-bearing 10, ie, the lower part of the crankshaft 5, mainly by the spiral groove 10r of the sub-bearing 10 provided on the anti-load surface against the compressive load. . Then, the lubrication of the crankshaft 5 and the lubrication and sealing between the members in the compression chamber are performed by the differential pressure between the upper and lower portions of the roller 11 with the oil.

  The remaining oil supplied to the central part of the crankshaft 5 flows to the upper part of the crankshaft 5 mainly by the spiral groove 6r of the main bearing 6 provided on the counter load surface against the compressive load. Then, the remaining oil lubricates the vicinity of the main bearing 6 and flows through the spiral groove 6r of the main bearing 6. Then, the oil discharged from the upper portion of the main bearing 6 to the central portion in the closed container 1 returns to the bottom body 1C at the bottom portion in the closed container 1 again. The reliability of the wear resistance of the compressor C is improved by such lubrication of the oil.

<Measures for refrigerant dissolution into oil>
However, refrigerant to be compressed is dissolved in the oil that lubricates the crankshaft 5, and there is a concern that the refrigerant containing the refrigerant may be decompressed to cause a foaming phenomenon of the refrigerant. When the refrigerant foaming phenomenon occurs, bubbles of the refrigerant gas are generated in the oil, and hinder lubrication of the crankshaft 5 part. For this reason, there is a concern that the reliability with respect to wear may be reduced.

  Therefore, it is desirable that the oil is not depressurized in the course of oil flow from the bottom of the closed casing 1 to the upper part of the main bearing 6 in the oil supply by the spiral grooves 10r and 6r of the compressor C. That is, it is desirable that the amount of oil supplied to the sub-bearing 10 be larger than that of the main bearing 6 so that oil is pushed out from the sub-bearing 10 toward the main bearing 6.

As described in the equation (1), the lubrication amounts of the main bearing 6 and the sub-bearing 10 are Q ₁ and Q ₂ , the crankshaft diameters are D ₁ and D ₂ , the crankshaft rotation speeds are N ₁ and N ₂ , and the spiral groove is The cross-sectional areas of 6r and 10r are A ₁ and A ₂ , and the angles of the spiral grooves 6r and 10r with respect to the horizontal direction of rotation of the crankshaft 5 (the plane perpendicular to the rotation axis) (hereinafter referred to as spiral groove angles) are θ ₁ and θ. _In the case of ₂ , the ideal lubrication amount relationship is that the auxiliary bearing 10 is located upstream of the main bearing 6 and requires a large lubrication amount.
Q ₁ (lubricating amount of main bearing 6) ≦ Q ₂ (lubricating amount of auxiliary bearing 10)
And Therefore,
_{A 1 × π × (D 1} /2) × N 1 × cosθ1 ≦ A 2 × π × (D 2/2) × N 2 × cosθ 2 ··· (2)
Here, .theta.1, theta ₂ is helical grooves 6r when the plane perpendicular to the rotation axis and the 0 °, the angle of 10r, 0 <θ1 <90 ° , is 0 <θ ₂ <90 °.

By transforming equation (2),
A ₁ × D ₁ × N ₁ × cos θ ₁ ≦ A ₂ × D ₂ × N ₂ × cos θ ₂
Here, since the rotation speed of the crankshaft 5 is the same for the main bearing 6 and the sub-bearing 10, N ₁ = N ₂ . Therefore,
A ₁ × D ₁ × cos θ ₁ ≦ A ₂ × D ₂ × cos θ ₂ (3)
Becomes

  As described above, lubrication can be smoothly performed from the upstream sub-bearing 10 to the downstream main bearing 6, and the reliability of wear resistance of the compressor C can be improved.

<< Embodiment 2 >>
FIG. 5 shows a vertical sectional view of the electric compressor C1 of the second embodiment.
In the compressor C1 according to the second embodiment, among the main bearing 6a and the sub-bearing 10a that receive a compressive load in the compressor C1, the shaft diameter of the sub-bearing 10a with a small compressive load is changed to the main bearing 6a with a large compressive load. Make it smaller. Thereby, the sliding loss generated in the bearings 6a and 10a is reduced while ensuring the reliability of the bearings (6a and 10a) against the compressive load.

Auxiliary bearing 10a of the compressor C1, since the shaft diameter _{D 2} is smaller than the shaft diameter _{D 1} of the main bearing 6a, the main bearing 6a, the oil supply amount Q = A × π × of formula (1) (D / 2) × N × cos θ D (diameter) (= D ₁ ) becomes smaller.
Therefore, the cross-sectional area A of the helical groove 10ar sub bearing 10a, if the spiral groove angle θ is equal to the spiral groove 6ar main bearing _6a, the oil supply amount _{Q 2} of Q 1> _{Q 2} next sub-bearing 10a is reduced. The spiral grooves 10ar and 6ar each have a substantially spiral shape.

Therefore, there is a concern that the reliability of the wear resistance of the compressor C1 may be reduced due to the foaming phenomenon of the refrigerant.
Therefore, even when D ₁ > D ₂ ,
A ₁ × D ₁ × cos θ ₁ ≦ A ₂ × D ₂ × cos θ ₂ (4)
Keep the relationship. Here, .theta.1, theta ₂ is helical grooves 6ar in the case of a plane perpendicular to 0 ° to each rotary shaft, the angle of 10ar, 0 <θ1 <90 ° , 0 <θ 2 <90 °
Thereby, the reliability of the wear resistance of the compressor C1 is improved.

<< Embodiment 3 >>
FIG. 6 shows a longitudinal sectional view of a hermetic electric compressor C2 according to the third embodiment.
The difference between the hermetic electric compressor C2 according to the third embodiment and the compressor C1 according to the second embodiment is that the compressor C2 has a configuration in which at least the spiral groove 10br of the auxiliary bearing 10b is provided on the bearing side. is there.

Compressor C1 according to the second embodiment, since the shaft diameter _{D 2} of the sub-bearing 10a is smaller than the shaft diameter _{D 1} of the main bearing _{6a, A 1 × D 1 ×} cosθ 1 ≦ A 2 × D 2 × cosθ 2 in order to maintain the relationship, increasing the cross-sectional area _{a 2} of the spiral grooves 10ar sub bearing 10a, or, it is necessary to reduce the angle theta ₁ of the spiral groove 6ar main bearing 6a. However, a helical groove provided on the side of the crankshaft 5 of the auxiliary bearing 10a, and, increasing the spiral groove cross-sectional area A _2, or reducing the spiral groove angle theta ₁ of the main bearing 6a, the axis stiffness of the auxiliary bearing Causes a decrease in Reference numeral 6br in the third embodiment indicates a spiral groove of the main bearing 6b.

  For this reason, in the third embodiment, a substantially helical spiral groove 10br is provided on the bearing side of the auxiliary bearing 10b of the crank 5, and a decrease in the shaft rigidity of the crankshaft 5 due to the installation of the spiral groove in the auxiliary bearing 10b is suppressed. . Thereby, the deformation of the crankshaft 5 due to the compression load can be suppressed. Therefore, the reliability of the wear resistance of the compressor C2 is improved.

<Modification of Third Embodiment>
FIG. 7A shows a spiral groove 5cr viewed from the center side of a crankshaft 5c of a hermetic electric compressor C3 according to a modification of the third embodiment, and FIG. 7B shows an enlarged view thereof. FIG. 7C shows a spiral groove 10br viewed from the center side of the auxiliary bearing 10b of the compressor C2 according to the third embodiment, and FIG. 7D shows an enlarged view thereof.

  The difference between the hermetic electric compressor C3 according to the modification of the third embodiment and the compressor C1 according to the second embodiment is that the compressor C3 has at least the spiral groove 10ar of the sub-bearing 10a instead of the spiral groove 10ar of FIG. ), A substantially spiral spiral groove 5cr is provided on the crankshaft 5c side so that the crankshaft 5c is solid.

By making the crankshaft 5c of the auxiliary bearing 10b solid, the strength can be improved. Further, the crank shaft 5c than be solid, increasing the spiral groove cross-sectional area A _2, or to mitigate the decrease in the rigidity of the crank shaft 5c which faces the auxiliary bearing 10b by reducing the spiral groove angle theta ₂ .

Thereby, the deformation of the crankshaft 5c due to the compressive load can be suppressed, and the mechanical reliability is improved.
Hereinafter, the difference in the inclination angle θ between the spiral groove on the crankshaft side and the spiral groove on the bearing side will be described.

As shown in FIG. 7A, when the spiral groove 5cr is provided on the crankshaft 5c side in the compressor C3 of the modified example, the spiral groove is formed on the bearing side of the auxiliary bearing 10b of the third embodiment shown in FIG. 7C. in the case of providing the 10bR, tilt angle theta ₂ is reversed (opposite sign + -) becomes. Note that -90 ° <-θ ₂ <0.
This is because when the crankshaft 5c (5b) rotates counterclockwise in a top view (arrows α1 in FIGS. 7A and 7B), the oil O in the spiral groove 5cr has a relative speed v1.
Since the relative speed v1 has a speed component v1a along the spiral groove 5cr, the oil O in the spiral groove 5cr flows upward toward the main bearing 6 along the spiral groove 5cr.

On the other hand, as shown in FIG. 7C, when the spiral groove 10br is provided in the auxiliary bearing 10b of the crank 5 of the third embodiment, the oil O in the spiral groove 10br has a relative speed v2.
Since the relative speed v2 has a speed component v2a along the spiral groove 10br, the oil O in the spiral groove 10br flows upward toward the main bearing 6 along the spiral groove 10br.

Here, when a spiral groove is provided on the side of the crankshaft 5c (FIG. 7 (a)), θ ₂ in Expressions (1) to (4) becomes −θ ₂ and a spiral groove is provided in the sub bearing 10. spiral groove angle theta ₂ and sign + in the case were - reversed. Note that -90 ° <-θ ₂ <0.

<< Embodiment 4 >>
FIG. 8 shows a longitudinal sectional view of a hermetic electric compressor C4 according to the fourth embodiment. FIGS. 9A, 9B, and 9C are a cross-sectional view of a main bearing 6d, a cross-sectional view of a sub-bearing 10d, and an external view of a crankshaft 5d of the fourth embodiment, respectively.
The difference between the hermetic electric compressor C4 according to the fourth embodiment and the compressors C1 and C2 according to the first and second embodiments is that the compressor C4 includes two or more spiral grooves 10dr having a substantially spiral shape in the sub-bearing 10d. It has a point.

The shaft diameters D ₁ and D ₂ of the main bearing 6d and the sub-bearing 10d of the compressor C4 are greatly affected by the shaft rigidity and the sliding loss generated in the bearing portion with respect to the compression load. Therefore, the adjustment of each parameter to maintain the relationship of A ₁ × D ₁ × cos θ ₁ ≦ A ₂ × D ₂ × cos θ _{2 in} the equation (3) is performed by adjusting the parameters other than the shaft diameters D ₁ and D ₂ related to the sliding loss. It is desirable to perform the process with the spiral groove cross-sectional areas A ₁ and A ₂ or the spiral groove angles θ ₁ and θ ₂ .

However, inconsistency of the cross-sectional areas A ₁ and A ₂ due to a single spiral groove often causes an increase in the specifications of the cutting tool at the time of spiral groove processing. Further, since the spiral groove angles θ ₁ and θ ₂ affect the spiral groove installation width angles of the bearing surfaces of the main bearing 6d and the sub bearing 10d, the spiral groove 10dr of the sub bearing 10d has a bearing surface of the crankshaft 5d which receives a compressive load. Do not touch Therefore, aiming to oil amount increases in the sub-bearing 10d, the case of reducing the spiral groove angle theta _2, the lower limit is present in the spiral groove angle theta _2.

  Therefore, two or more spiral grooves 10dr of substantially the same shape and substantially parallel are provided in the sub bearing 10d. Thereby, it is possible to suppress an increase in the specifications of the cutting tool at the time of the spiral groove processing and to prevent the spiral groove 10dr of the auxiliary bearing 10d from contacting the bearing surface of the crankshaft 5d which receives a compressive load. The spiral groove 10dr has a substantially spiral shape.

However, when two or more spiral grooves 10dr of substantially the same shape and substantially parallel are provided in the auxiliary bearing 10d, the same effect can be obtained even if the plurality of spiral grooves 10dr overlap each other.
The main bearing 6d may be provided with two or more spiral grooves 6dr (two-dot chain line in FIG. 9A) having substantially the same shape and being substantially parallel.

<< Embodiment 5 >>
FIG. 10 is a longitudinal sectional view of a hermetic electric compressor C5 according to the fifth embodiment and a modification. FIG. 11A shows a longitudinal sectional view of the main bearing 6e of the fifth embodiment, and FIG. 11B shows a longitudinal sectional view of the auxiliary bearing 10e of the fifth embodiment.
The difference between the hermetic electric compressor C5 according to the fifth embodiment and the compressors C1 and C2 according to the first and second embodiments is that the compressor C5 has a configuration in which the eccentric portion 5e1 of the crankshaft 5e has a spiral groove 5er. It has a point. Reference numeral 6er in the fifth embodiment indicates a spiral groove of the main bearing 6e.

  In the compressor C1 (C2) according to the first and second embodiments, the oil supplied to the lower portion of the eccentric portion 5h of the crankshaft 5 by the spiral groove 10r (10ar) of the auxiliary bearing 10 (10a) The oil is stored in 5 hours. Then, the oil level is pushed up by further oil supply from the spiral groove 6r (6ar) of the sub bearing 6 (6a). Then, it reaches the lower part of the main bearing 6 (6a), and is circulated to the upper part by the spiral groove 6r (6ar) of the main bearing 6 (6a). For this reason, the circulation of the oil in the eccentric part 5h of the crankshaft 5 is performed only by the passive effect of pushing up by the oil supply force from the spiral groove 6r (6ar) of the auxiliary bearing 6 (6a).

  However, the hermetic electric compressor C5 according to the fifth embodiment is configured such that the eccentric portion 5e1 of the crankshaft 5e mainly faces the counter load surface against the compressive load, and the rotation of the crankshaft 5e moves from the auxiliary bearing 10e to the main bearing 6e. And a spiral groove 5er having a substantially spiral shape for conveying oil. Thus, the oil that has reached the lower part of the eccentric part 5e1 of the crankshaft 5e can be circulated to the upper part of the eccentric part 5e1 of the crankshaft 5e by the viscous pump including the rotation of the eccentric part 5e1 of the crankshaft 5e and the spiral groove 5er. it can.

  Accordingly, even when the rotational speed of the crankshaft 5e is low, that is, when the pushing force due to the lubricating force of the substantially spiral spiral groove 10er provided in the sub-bearing 10e is small, the spiral groove of the eccentric portion 5e1 of the crankshaft 5e. 5er allows the oil to flow from the lower part to the upper part of the eccentric part 5e1 of the crankshaft 5e. Therefore, the reliability of wear resistance of the eccentric portion 5e1 and the like of the crankshaft 5e is improved.

<Modification>
FIG. 12A is an external view of a crankshaft 5e of a hermetic electric compressor C6 according to a modification of the fifth embodiment, and FIG. 12B is a cross-sectional view taken along the line CC of FIG. (c) shows a development view of the eccentric portion 5e1.
The difference between the compressor C6 according to the modification of the fifth embodiment and the compressor C5 according to the fifth embodiment is that the compressor C6 has a cross section of the helical groove 5er of the eccentric part 5e1 of the crankshaft 5e as A ₃ , The relationship when the diameter is D ₃ and the angle of the spiral groove 5er with respect to the rotation direction horizontal (the plane perpendicular to the rotation axis) of the crankshaft 5e is θ ₃ is as follows:
A ₁ × D ₁ × cos θ ₁ ≦ A ₃ × D ₃ × cos θ ₃ ≦ A ₂ × D ₂ × cos θ ₂ ... Equation (5)
This is the point formed. Here, −90 ° <θ ₃ <0
The spiral groove 5er may be plural.

  According to the modified example, even in the eccentric portion 5e1 of the crankshaft 5e, the foaming phenomenon of the refrigerant can be suppressed, and the reliability against wear can be improved.

According to the above configuration, even when the shaft diameters D _{1 and} D ₂ , the cross-sectional areas A ₁ and A ₂ of the oil supply grooves and the angles θ ₁ and θ _{2 of the} oil supply grooves of the main bearing 6 and the sub-bearing portion 10 are different from each other, lubrication is performed. The amount can be 6 parts of main bearings ≦ 10 parts of auxiliary bearings. Therefore, oil is supplied to the compression chamber by the flow of oil to the eccentric portion 5h of the crankshaft 5 and the differential pressure from the upper and lower surfaces of the roller 11. Further, pressure reduction due to a difference in the amount of refueling in the refueling grooves (6r, 10r) can be suppressed. Therefore, foaming of the refrigerant dissolved in the oil is suppressed, and the oil supply grooves (6r, 10r) can be filled with the oil, so that the reliability against wear can be improved.

  Accordingly, in various types of hermetic electric compressors, the lubricating properties of the auxiliary bearing portion 10, the eccentric portion 5h of the crankshaft 5, and the main bearing 6 are improved, and the hermetic electric compressor C having high reliability with respect to wear is provided. it can.

<< Other embodiments >>
1. In the embodiment and the modified examples, the case where the auxiliary bearing portion, the crankshaft eccentric portion, and the main bearing portion of the electric compressor are provided with the helical groove has been described, but among the auxiliary bearing portion, the crankshaft eccentric portion, and the main bearing portion, At least one of the spiral grooves may be provided. In this case, a spiral groove may be provided on the bearing side or the crankshaft side. When the spiral groove is provided on the crankshaft side, as described in the modified example of the third embodiment, the spiral groove provided on the bearing side has an inclination opposite to that of the spiral groove.

2. In the above embodiments and modifications, the case where the crankshaft rotates counterclockwise as viewed from above is described. However, the present invention is also applicable to the case where the crankshaft rotates clockwise as viewed from above. When the crankshaft rotates clockwise in a top view, the inclination angle of the helical groove is the inclination in the direction opposite to the inclination described in the embodiment and the modification.

3. The spiral groove provided in the sub-bearing portion, the crankshaft eccentric portion and the main bearing portion of the electric compressor may be singular or plural.

4. Note that the present invention is not limited to the above-described embodiments and modified examples, and can be variously modified without departing from the gist of the present invention.

1 closed container (accommodation part)
5, 5b, 5d, 5e Crankshaft 5c Crankshaft (Solid crankshaft)
5er spiral groove (substantially spiral groove)
5h Eccentric part of crankshaft 6, 6a, 6b, 6c, 6d Main bearing 10, 10a, 10b, 10c, 10d Secondary bearing 6r, 6ar, 6dr Spiral groove (substantially spiral groove)
10r, 10ar, 10br, 10cr Spiral groove (substantially spiral groove)
10dr helical groove (substantially helical groove of the bearing, approximately the same cross-sectional shape, and approximately parallel helical groove)
Sectional area of the spiral groove of A ₁ main bearing (cross-sectional area of the groove of substantially spiral shape of the main bearing)
Sectional area of the spiral groove of the A ₂ sub bearing (cross-sectional area of the groove of substantially spiral shape sub bearing)
Sectional area of A ₃ helical groove (cross-sectional area of the groove of substantially spiral shape of the eccentric portion of the crank shaft)
C, C1, C2, C3, C4 Electric compressor (closed electric compressor)
D Electric element (motor)
D ₁ Shaft diameter of main bearing D ₂ Shaft diameter of sub-bearing D ₃ Shaft diameter of eccentric part of crankshaft K Compression mechanism θ ₁ Angle of spiral groove of main bearing with respect to horizontal in the rotation direction of crankshaft (generally spiral of main bearing) Angle of the groove of the shape to the horizontal direction of rotation of the crankshaft)
angle with respect to theta ₂ rotating direction horizontal crankshaft of the groove of the eccentric portion of the angle theta ₃ crankshaft for rotation direction horizontal crankshaft groove substantially spiral shape sub bearing

Claims (10)

Electric motor,
A compression mechanism that has a crankshaft that is rotationally driven by the electric motor, a main bearing and a sub-bearing that supports the crankshaft, and a sliding surface between the crankshaft and the main and sub-bearings is lubricated with lubricating oil Department and
A housing for housing the motor and the compression mechanism,
The main bearing and the auxiliary bearing,
Due to the rotation of the crankshaft, in the direction from the sub-bearing to the main bearing, a substantially helical groove for conveying the lubricating oil is provided on the crankshaft side or the bearing side of the main bearing and the sub-bearing, The cross-sectional areas of the substantially spiral grooves of the main bearing and the sub-bearing are A ₁ and A ₂ , the shaft diameters are D ₁ and D ₂ , and the angles of the substantially spiral grooves with respect to the rotation direction horizontal of the crankshaft. The relationship when θ ₁ and θ ₂ is
A ₁ × D ₁ × cos θ ₁ ≦ A ₂ × D ₂ × cos θ ₂
Here, the grooves provided in the main bearing and the sub-bearing satisfy 0 ° <θ ₁ , θ ₂ <90 ° when the horizontal in the rotation direction is 0 °, and the grooves provided in the crankshaft are , When the horizontal in the rotation direction is 0 °, −90 ° <θ ₁ , θ ₂ <0 °
A hermetic electric compressor characterized by being formed so that The hermetic electric compressor according to claim 1,
Relationship shaft diameter D ₂ of said auxiliary bearing and shaft diameter D ₁ of the said main bearing,
D ₁ > D ₂
A hermetic electric compressor characterized by being formed so that The hermetic electric compressor according to claim 1,
Relationship shaft diameter D ₂ of said auxiliary bearing and shaft diameter D ₁ of the said main bearing,
D ₁ > D ₂
It is formed so that
A hermetic electric compressor, characterized in that at least the substantially spiral groove of the sub bearing is provided on the bearing side of the sub bearing. The hermetic electric compressor according to claim 1,
Relationship shaft diameter D ₂ of said auxiliary bearing and shaft diameter D ₁ of the said main bearing,
D ₁ > D ₂
It is formed so that
A hermetic electric compressor, wherein at least the substantially spiral groove relating to the auxiliary bearing is provided on the crankshaft side of the auxiliary bearing, and the crankshaft of the auxiliary bearing is solid. The hermetic electric compressor according to claim 1,
The hermetic electric compressor, wherein the auxiliary bearing has a plurality of the substantially spiral grooves having substantially the same cross-sectional shape and being substantially parallel to each other. The hermetic electric compressor according to claim 1,
The hermetic electric compressor, wherein the main bearing has a plurality of the substantially helical grooves having substantially the same cross-sectional shape and being substantially parallel. The hermetic electric compressor according to claim 1,
The hermetic electric compressor, wherein each of the grooves on the crankshaft side or the bearing side of the main bearing and the sub-bearing is singular or plural. The hermetic electric compressor according to claim 1,
The eccentric portion of the crankshaft has a substantially helical groove for conveying the lubricating oil in a direction from the sub bearing to the main bearing by rotation of the crankshaft. Type electric compressor. The hermetic electric compressor according to claim 1,
The eccentric portion of the crankshaft has a substantially helical groove for conveying the lubricating oil in the direction from the auxiliary bearing to the main bearing by the rotation of the crankshaft,
The relationship when the cross-sectional area of the substantially spiral groove of the eccentric portion of the crankshaft is A ₃ , the shaft diameter is D ₃ , and the angle of the groove with respect to the rotation direction horizontal direction of the crankshaft is θ ₃ ,
A ₁ × D ₁ × cos θ ₁ ≦ A ₃ × D ₃ × cos θ ₃ ≦ A ₂ × D ₂ × cos θ ₂
However, the groove provided in the eccentric portion of the crankshaft is -90 ° <θ ₃ <0 ° when the horizontal in the rotation direction is 0 °.
A hermetic electric compressor characterized by being formed so that The hermetic electric compressor according to claim 1,
The eccentric portion of the crankshaft has a substantially helical groove for conveying the lubricating oil in the direction from the auxiliary bearing to the main bearing by the rotation of the crankshaft,
The relationship when the cross-sectional area of the substantially helical groove of the eccentric portion of the crankshaft is A ₃ , the shaft diameter is D ₃ , and the angle of the helical groove with respect to the rotation direction horizontal of the crankshaft is θ ₃ is as follows. ,
A ₁ × D ₁ × cos θ ₁ ≦ A ₃ × D ₃ × cos θ ₃ ≦ A ₂ × D ₂ × cos θ ₂
However, when the groove provided in the eccentric portion of the crankshaft has a horizontal rotation direction of 0 °,
−90 ° <θ ₃ <0 °
It is formed so that
The groove of the eccentric portion of the crankshaft is singular or plural. A hermetic electric compressor.

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