JP2001355586A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary compressor having high reliability by suitably distributing surface pressure acting on a main bearing and an auxiliary bearing from a crankshaft. SOLUTION: The axial length of a main bearing 9 is taken as Ha, the distance between the axial center 12 of the main bearing 9 and the axial center 13 of an eccentric bearing part 5 is taken as La, the inside diameter of the main bearing 9 is taken as Da, the axial length of an auxiliary bearing 10 is taken as Hb, the distance between the axial center 14 of the auxiliary bearing 10 and the axial center 13 of the eccentric bearing part 5 is taken as Lb, and the inside diameter Db of the auxiliary bearing 10 is found from the expression: Db=Da.(Ha.La)/(Hb.Lb). Therefore, surface pressure acting on the main bearing 9 and the auxiliary bearing 10 are equalized to each other, and excessive surface pressure does not act on one bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor used for an air conditioner or a refrigerator.

[0002]

2. Description of the Related Art As a conventional technique related to a rotary compressor, a technique disclosed in Japanese Patent Publication No. 2513782 will be described as an example with reference to FIG.

[0003] Inside the closed container 1, an electric motor unit 2 is provided at the upper part,
A compression mechanism 3 driven by the electric motor 2
And has been set up. The compression mechanism 3 includes a crankshaft 4 having an eccentric shaft 5 for transmitting the rotational force of the electric motor 2 to the compression mechanism 3, and a piston rotatably fitted to the eccentric shaft 5. 6, a cylinder 7 having a cylindrical air chamber, a vane 8 slidably fitted in a groove provided in the cylinder 7, and a crankshaft installed at both axial ends of the cylinder 7. 4 comprises a main bearing 9 and an auxiliary bearing 10 which rotatably support the main bearing 4.

In the above configuration, the piston 6 mounted on the eccentric shaft portion 5 of the crankshaft 4 performs eccentric rotational movement in the cylinder 7, and as a result, the refrigerant gas sucked from the suction hole 11 is And is discharged by a discharge hole (not shown).

[0005] A lubricating oil is stored at the bottom of the closed casing 1 to lubricate sliding parts such as the crankshaft 4 and the main bearing 9 and the sub-bearing 10.

The crankshaft 4 has a force that is pushed through the piston 6 by the pressure difference of the refrigerant gas inside the cylinder 7,
The combined force of the three forces of the vane 8 pushing through the piston 6 and the centrifugal force generated by the rotation of the eccentric shaft 5 and the piston 6 fitted to the eccentric shaft 5 mainly acts. . Among these forces, the unbalance force due to the centrifugal force is completely balanced by, for example, installing appropriate balance weights above and below the rotor of the electric motor unit 2 installed at one end of the crankshaft 4. Can be. However, the unbalanced inertial force due to the reciprocating motion of the vane 8 is
The balance cannot be completely balanced, and the unbalance amount corresponding to 1/2 of the mass of the vane 8 is generally added to the balance weight using the concept of partial balancing.

On the other hand, the resultant force of the force due to the pressure difference of the refrigerant gas and the force by which the vane 8 pushes the piston 6 does not coincide with the eccentric direction of the eccentric shaft 5, so that the main bearing 9 and the sub bearing 10 and will be received as a bearing load force. Thus, the main bearing 9 and the sub bearing 10 receive a surface pressure from the crankshaft 4 according to the bearing load force.

In the conventional rotary compressor, when the crankshaft 4 reaches the maximum compression load during one rotation, the eccentric amount at which the surface pressures applied to the main bearing 9 and the sub-bearing 10 become substantially uniform is obtained by: The auxiliary bearing 10 supporting the crankshaft 4 is replaced with the main bearing 9
On the other hand, the eccentricity Δe is eccentric to the side opposite to the side where the maximum compression load is generated. As a result, the surface pressure generated in the main bearing 9 and the sub-bearing 10 is made a uniform dynamic pressure,
It is intended to improve reliability.

[0009]

However, in the above-mentioned conventional compressor, it is effective if the magnitude of the maximum compression load generated during one revolution of the crankshaft is always the same. Varies in size. That is,
In the case of the operating condition of the refrigeration cycle to which the compressor is connected or the variable speed controlled by the inverter, the load on the compressor greatly changes depending on the operating speed of the motor. It is necessary to change the amount Δe of eccentricity with respect to the bearing so as to be optimal. Therefore, in the above-mentioned conventional example, depending on the operating conditions or operating speed, if the auxiliary bearing is eccentric with respect to the main bearing, the pressure on one bearing surface may be excessively increased.

In the case of a general rotary compressor, the bearing clearance between the crankshaft and the main and auxiliary bearings is about 1/1000 of the inner diameter of the bearing. For example, the inner diameter of the bearing is 20 mm. In the case of the above, the bearing gap is about 20 μm
Therefore, in order to make the auxiliary bearing eccentric with respect to the main bearing as in the above-mentioned conventional example, it has to be positioned between the minute bearing gaps, and very precise assembly is required.

In a vertical hermetic compressor in which the compression mechanism is installed below, even when the oil level of the lubricating oil is low due to the operating conditions of the compressor, etc., the auxiliary bearing is relatively small. Although sufficient lubricating oil was supplied, a main bearing that required a larger lift sometimes lacked lubricating oil. For this reason, there has been a problem that wear of the crankshaft in contact with the main bearing or the upper bearing becomes severe and reliability is reduced.

In recent years, due to various regulations, HFC (Hydro Fluoro Carbon) containing no chlorine atom has been used as a highly practical alternative refrigerant in place of the conventionally used refrigerants such as Freon R12 and Freon 22. It is getting. However, since this alternative refrigerant does not contain chlorine atoms, lubricating properties are poor compared to Freon R12 and R22, and the operating pressure is relatively high due to the physical properties of the refrigerant, so that the bearing surface pressure increases, and as a result, the bearing However, there is a problem that the reliability is lowered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has a highly reliable rotation by allowing a surface pressure acting from a crankshaft to act on a main bearing and an auxiliary bearing in an optimally distributed manner. It is an object of the present invention to provide a type compressor.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an inner diameter of each of a main bearing and an auxiliary bearing, an axial length of these bearings, and an axial center of an eccentric shaft portion of a crankshaft. Is set to a dimension such that the surface pressure acting on the main bearing and the sub-bearing from the crankshaft is optimally distributed and acts on the main bearing and the sub-bearing.

As a result, the surface pressure acting on the main bearing and the sub-bearing from the crankshaft is always distributed and acted optimally, so that the reliability can be improved.

[0016]

According to the first aspect of the present invention, there is provided a crankshaft having an eccentric shaft, a piston rotatably fitted to the eccentric shaft and installed.
A cylinder having a cylindrical air chamber; a vane slidably fitted in a groove provided in the cylinder; and a vane installed at both axial ends of the cylinder to rotatably rotate the crankshaft. A rotary compressor having a compression mechanism portion comprising a main bearing and a sub-bearing, wherein an axial length of the main bearing is Ha, an axial center of the main bearing, and an axial center of the eccentric shaft portion. Is La, the inner diameter of the main bearing is Da,
When the axial length of the sub-bearing is Hb, and the distance between the axial center of the sub-bearing and the axial center of the eccentric shaft portion is Lb, the inner diameter Db of the sub-bearing is expressed by the following equation (1). It was done. As a result, the surface pressure acting on the main bearing and the sub-bearing from the crankshaft becomes equal, and there is no possibility that an excessive surface pressure acts on one of the bearings.

According to a second aspect of the present invention, there is provided an electric motor unit which is supplied with power from the outside to generate a rotational force, a compression mechanism disposed below the electric motor unit, and a compression mechanism disposed below the compression mechanism. The collected lubricating oil reservoir is stored in a closed container,
The compression mechanism is a crankshaft having an eccentric shaft, a piston rotatably fitted to the eccentric shaft and installed,
A cylinder having a cylindrical air chamber; a vane slidably fitted in a groove provided in the cylinder; and a vane installed at both axial ends of the cylinder to rotatably rotate the crankshaft. A rotary compressor comprising a main bearing and a sub-bearing to be supported, wherein the lubricating oil stored in the lubricating oil reservoir is sucked up to lubricate the bearing and the compressor unit, and the axial length of the main bearing Ha, the distance between the axial center of the main bearing and the axial center of the eccentric shaft portion is La, the inner diameter of the main bearing is Da, the axial length of the sub bearing is Hb, and the axial direction of the sub bearing is When the distance between the center and the center of the eccentric shaft portion in the axial direction is Lb, the inner diameter Db of the sub bearing is expressed as (Equation 2). As a result, even when the lubricating oil supplied to the main bearing is insufficient compared to the sub-bearing, the surface pressure acting on the main bearing can be reduced as compared with the surface pressure acting on the sub-bearing. The progress of wear of the main bearing can be suppressed.

According to a third aspect of the present invention, as the refrigerant, a mixed refrigerant obtained by mixing at least one kind or a mixture of two or more kinds in a hydrocarbon group based on hydrogen fluoride is used. As a result, the lubricating properties are lower than those of the conventional Freon R12 and R22, and the operating pressure is relatively high due to the physical properties of the refrigerant, so that even if the bearing surface pressure increases, the crankshaft is always provided on the main bearing and the sub bearing. Since the surface pressure acting from above can be distributed and acted optimally, the reliability can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the present embodiment, the same parts as those of the configuration shown in the above-mentioned conventional technique are denoted by the same reference numerals, detailed description thereof will be omitted, and only different parts will be described. Further, in the present embodiment, it is not necessary to decenter the auxiliary bearing 10 by Δe with respect to the main bearing 9 as described in the above-mentioned conventional technology.

(Embodiment 1) In FIG. 1, the axial length of the main bearing 9 is Ha, and the distance between the axial center 12 of the main bearing 9 and the axial center 13 of the eccentric shaft portion 5 of the crankshaft 4 is La. , The inner diameter of the main bearing 9 is Da, the axial length of the sub-bearing 10 is Hb,
When the distance between the axial center 14 of the sub bearing 10 and the axial center 13 of the eccentric shaft portion 5 is Lb, the inner diameter Db of the sub bearing 10
Is a dimension determined by (Equation 1).

In FIG. 1, F is a resultant force generated when the gas is compressed, and acts on the eccentric shaft portion 5 of the crankshaft 4 via the piston 6. The resultant force F is received by the main bearing 9 and the sub bearing 10 as bearing load forces Ra and Rb, respectively. Thus, the main bearing 9 and the sub bearing 1
0 receives the surface pressures Pa and Pb from the crankshaft 4 according to the bearing load forces Ra and Rb, respectively.

The bearing load forces Ra and Rb can be expressed by the following (Equation 3) and (Equation 4), respectively, by balancing the moments.

[0023]

(Equation 3)

[0024]

(Equation 4)

Therefore, the surface pressure P received by each of the bearings 9 and 10
a and Pb can be expressed by the following (Equation 5) and (Equation 6) by dividing these by the bearing projected area.

[0026]

(Equation 5)

[0027]

(Equation 6)

By substituting (Equation 3) and (Equation 4) for these (Equation 5) and (Equation 6), respectively, the following is obtained.

[0029]

(Equation 7)

[0030]

(Equation 8)

Here, since the inner diameter Db of the sub bearing 10 is set to the dimension determined by the above (Equation 1), it is calculated by the following (Equation 8).
, The surface pressure Pb received by the sub-bearing 10 is given by the following (Equation 9).

[0032]

(Equation 9)

Therefore, from (Equation 7) and (Equation 9), Pa =
Pb, and the surface pressures Pa and Pb respectively received by the main bearing 9 and the sub-bearing 10 become equal. Therefore, an excessive surface pressure does not act on one of the bearings, and the progress of wear of the main bearing 9, the sub-bearing 10, and the crankshaft 4 can be suppressed, and the reliability is improved. be able to.

Incidentally, the axial length Ha of the main bearing 9 is 4
0 mm, the distance La between the axial center 12 of the main bearing 9 and the axial center 13 of the eccentric shaft portion 5 of the crankshaft 4 is 30 mm, the inner diameter Da of the main bearing 9 is 20 mm, and the axial length Hb of the sub bearing 10 is When the distance Lb between the axial center 14 of the sub-bearing 10 and the axial center 13 of the eccentric shaft portion 5 is 30 mm, and the inner diameter Db of the sub-bearing 10 is 32 mm from (Equation 1). At this time, the resultant force acting on the crankshaft 4 generated when the gas is compressed is used as F to obtain the main bearing 9 and the sub-bearing 10.
The surface pressures Pa and Pb respectively received from (Equation 7) and (Equation 8) become the following (Equation 10) and (Equation 11), which are equal.

[0035]

(Equation 10)

[0036]

[Equation 11]

Although this embodiment has been described with reference to a vertical hermetic rotary compressor, the same operational effects can be obtained with a horizontal or open rotary compressor.

(Second Embodiment) In the second embodiment, the same parts as those in the prior art and the structure shown in the first embodiment are denoted by the same reference numerals, detailed description thereof will be omitted, and only different parts will be described. explain.

In FIG. 1, the axial length of the main bearing 9 is H
a, the distance between the axial center 12 of the main bearing 9 and the axial center 13 of the eccentric shaft portion 5 of the crankshaft 4 is La, the inner diameter of the main bearing 9 is Da, the axial length of the sub bearing 10 is Hb, When the distance between the axial center 14 of the bearing 10 and the axial center 13 of the eccentric shaft portion 5 is Lb, the inner diameter Db of the sub-bearing 10 is set to a size determined by (Equation 2).

As in the case of the first embodiment, each of the bearings 9, 10
The surface pressures Pa and Pb received at
2) and (Expression 13).

[0041]

(Equation 12)

[0042]

(Equation 13)

Here, since the inner diameter Db of the auxiliary bearing 10 is a dimension determined by (Equation 2), by substituting this into (Equation 13), the surface pressure Pb received by the auxiliary bearing 10 becomes (Equation 1)
4).

[0044]

[Equation 14]

Therefore, from (Equation 12) and (Equation 14), P
a <Pb, and the surface pressure Pb received by the sub-bearing 10 becomes larger than the surface pressure Pa received by the main bearing 9. Therefore, the oil level of the lubricating oil is low due to the operating conditions of the compressor and the like, and the auxiliary bearing 10 is supplied with a relatively sufficient lubricating oil.
Even when lubricating oil is insufficient for the main bearing 9 requiring a larger head, progress of wear of the main bearing 9 and the crankshaft 4 can be suppressed, and reliability can be improved.

(Third Embodiment) In the third embodiment, the same reference numerals are given to the same portions as those of the conventional art and the configurations shown in the first and second embodiments, and the detailed description is omitted. Only different points will be described.

As the refrigerant, a mixed refrigerant obtained by mixing at least one kind or two or more kinds in the group consisting of a hydrocarbon-hydrocarbon group is used. Since this refrigerant does not contain chlorine atoms, lubricating properties are poor, and the operating pressure is relatively high due to the physical properties of the refrigerant. However, as described in the first embodiment or the second embodiment, the main bearing 9, Since the optimum surface pressure can be distributed and acted on the auxiliary bearing 10, the main bearing 9,
The wear of the auxiliary bearing 10 and the crankshaft 4 can be prevented from progressing, and the reliability can be improved.

[0048]

As is apparent from the above embodiment, according to the first aspect of the present invention, the inner diameters of the main bearing and the sub-bearing, the axial lengths of these bearings, and the eccentric shaft of the crankshaft. The relationship of each distance between the axial center of these parts and the axial center of these parts is set so that the surface pressure acting on the main bearing and the sub-bearing from the crankshaft is the same. The surface pressure acting on the auxiliary bearing from the crankshaft is always the same, and there is no possibility that an excessive surface pressure acts on one bearing.

According to the second aspect of the present invention, in the vertical hermetic compressor in which the compression mechanism is installed below, the oil level of the lubricating oil is low due to the operating conditions of the compressor, etc. The secondary bearing is supplied with relatively sufficient lubricating oil,
Even if lubricating oil is insufficient for the main bearings that require a larger lift, the inner diameters of the main and sub bearings, the axial lengths of these bearings, and the axial direction of the eccentric shaft of the crankshaft The relationship of each distance from the center to the axial center of these bearings is set so that the surface pressure acting from the crankshaft makes the main bearing smaller than the sub-bearing. The progress of wear can be suppressed.

According to the third aspect of the present invention, even when the alternative refrigerant is used as the refrigerant and the lubricating properties are relatively poor and the load force is high, the optimum surface for the main bearing and the sub-bearing is always obtained. Pressure can be distributed and acted on.

As described above, the optimum surface pressure can be distributed and acted on both bearings in an easy manner and reliably, and a highly reliable rotary compressor can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rotary compressor showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a conventional rotary compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Electric motor part 3 Compression mechanism part 4 Crankshaft 5 Eccentric shaft part 6 Piston 7 Cylinder 8 Vane 9 Main bearing 10 Sub bearing 11 Suction port 12 Main bearing axial center 13 Eccentric shaft axial center 14 Sub bearing axial direction center

Claims (3)

[Claims] 1. A crankshaft having an eccentric shaft portion, a piston rotatably fitted to the eccentric shaft portion of the crankshaft, a cylinder having a cylindrical air chamber, and a cylinder provided in the cylinder. And a compression mechanism portion including a main bearing and a sub-bearing which are installed at both ends in the axial direction of the cylinder and which rotatably support the crankshaft. A rotary compressor, wherein the axial length of the main bearing is Ha, the distance between the axial center of the main bearing and the axial center of the eccentric shaft portion of the crankshaft is La,
The inner diameter of the main bearing is Da, and the axial length of the sub bearing is H.
b, when the distance between the axial center of the auxiliary bearing and the axial center of the eccentric shaft portion is Lb, the inner diameter Db of the auxiliary bearing
But, A rotary compressor. 2. An electric motor unit which is supplied with power from the outside to generate a rotational force, a compression mechanism unit disposed below the electric motor unit, and a lubricating oil reservoir disposed below the compression mechanism unit. Stored in a closed container, the compression mechanism is a crankshaft having an eccentric shaft, a piston rotatably fitted to the eccentric shaft, and a cylinder having a cylindrical air chamber, A vane slidably fitted in a groove provided in the cylinder, and a main bearing and a sub bearing installed at both ends in the axial direction of the cylinder to rotatably support the crankshaft. A rotary compressor for lubricating the bearing and the compression mechanism portion by lubricating oil stored in the lubricating oil reservoir being sucked up by an oil supply mechanism, wherein the axial length of the main bearing is Ha, the main bearing is Axial center of the eccentric shaft and the axial direction of the eccentric shaft When the distance from the center is La, the inner diameter of the main bearing is Da, the axial length of the auxiliary bearing is Hb, and the distance between the axial center of the auxiliary bearing and the axial center of the eccentric shaft is Lb. , The inner diameter Db of the auxiliary bearing is: A rotary compressor. 3. The rotary compression system according to claim 1, wherein a mixed refrigerant obtained by mixing at least one of a group of carbon fluoride-based refrigerants is used as the working fluid. Machine.