JPH0626479A - Multicylinder rotary compressor - Google Patents

Abstract

PURPOSE:To obtain a multistage rotary compressor which prevents a support condition of a shaft from being affected by a main bearing. CONSTITUTION:A motor part 3 is composed of rollers respectively arranged in cylinders 5, 6, blades 11 whose ends are in elastic contact with outer peripheral surfaces of the rollers, a shaft 8 which has eccentric shaft parts 9a, 9b for eccentrically rotate the rollers and is rotatably supported by bearings 15, 16 arranged on upper and lower sides of the cylinders, a rotor 17 whose axis center is agreed with that of the shaft, and a stator 10 which houses the rotor. The motor part 3 has a brushless dc motor part provided with a permanent magnet on the rotor. A gap between an inner diameter of the stator and an outer diameter of the rotor at the position dislocated by zero degree from the blades around the axis center of the shaft in a circumferencial direction is smaller than the gap therebetween at the position dislocated by 180 degrees from the blades in the circumferencial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder type rotary compressor having a plurality of cylinders.

[0002]

2. Description of the Related Art Rotary compressors are widely used as compressors for air conditioning. Especially in recent years, the frequency variable,
The so-called inverter type compressor is the mainstream, but the expansion of the variable width (minimum to maximum operating frequency) is required for the compressor in order to improve the comfort of the air conditioner.

In the conventional one-cylinder rotary compressor, when the minimum rotation speed is lowered, the operating vibration of the compressor is remarkably increased, and when the maximum rotation speed is raised, the whirling of the rotor (bending of the shaft) is caused. However, in order to solve these problems, a two-cylinder rotary compressor having a small fluctuation in compression torque and an excellent rotation balance characteristic has been used.

While the two-cylinder rotary compressor has the above-mentioned advantages, it has the following drawbacks. In other words, as a characteristic of the two-cylinder rotary compressor, when operating by compressing the refrigerant gas, the locus in the main bearing of the shaft center is
When the center of rotation is set as the origin of the rotation direction, the operation is performed in a state of being eccentric in a direction of approximately 180 degrees. That is, the operation is performed with eccentricity in the anti-blade direction. It is considered that the reason is that the shaft receives a pressing force by the blade via the roller.

When operated in such a state, particularly in the upper part of the main bearing, the bearing reaction force of this part increases, and the oil film thickness becomes small, so that the reliability of the supporting state of the main bearing deteriorates. Sometimes it brings.

[0006]

As described above, in the conventional multi-stage rotary compressor, since the shaft is largely eccentrically rotated in a direction deviated from the blade by 180 degrees in the circumferential direction,
The oil film pressure at that portion was reduced, and the reliability of the support state of the main bearing was sometimes reduced.

The present invention has been made in view of the above circumstances. An object of the present invention is to improve the reliability of the support state of the shaft in the main bearing by reducing the amount of eccentricity of the shaft during operation. An object of the present invention is to provide a multi-stage rotary compressor that can be used.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a plurality of cylinders, rollers provided in the cylinders, and an elastic tip at the outer peripheral surface of the rollers. A blade provided in pressure contact with the shaft, a shaft having an eccentric shaft portion for eccentrically rotating the roller and rotatably supported by bearings arranged above and below the cylinder, and an axis center of the shaft. A rotor and a stator having the rotor housed therein, and the rotor includes a brushless DC motor having permanent magnets on the rotor. , A gap between the inner diameter of the stator and the outer diameter of the rotor at a position of 0 degrees in the circumferential direction from the blade about the axis of the shaft is 180 degrees in the circumferential direction from the blade. The feature is that it is smaller than the gap at the position. To.

[0009]

According to the above construction, the shaft is eccentric in the blade direction in advance, and the rotor provided with the permanent magnet is attracted in the blade direction by the magnetic force generated between the rotor and the stator. Therefore, it is possible to prevent the shaft that rotates due to the pressing force of the blade from being largely eccentric with respect to the bearing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The multi-cylinder type rotary compressor shown in FIG. 3 is provided with a closed case 1. A compressor unit 2 and an electric motor unit 3 for driving the compressor unit 2 are provided inside the closed case 1. The compressor unit 2 includes a first cylinder 5 and a second cylinder 6 which are joined to each other in the vertical direction via a partition plate 4. A cylindrical roller 7 is provided in each of the cylinders 5 and 6, and the motor 7
The first eccentric shaft portion 9a and the second eccentric shaft portion 9b formed on the shaft 8 are rotatably fitted and inserted.
Therefore, when the shaft 8 is rotationally driven as described later, the pair of rollers 7 are eccentrically rotated in the respective cylinders 5 and 6.

Blades 11 are provided at the same positions in the circumferential direction of the cylinders 5 and 6 so as to be slidable in the radial direction. Each blade 11 is a spring 12
Is urged in the direction in which the tip is pressed against the outer peripheral surface of the roller 7. A connecting pipe 13 is attached to each of the cylinders 5 and 6.
The accumulator 14 is connected via. A gas refrigerant is supplied from the accumulator 14 to each of the cylinders 5 and 6.

An auxiliary bearing 15 is joined and fixed to the lower surface side of the first cylinder 5, and a main bearing 16 is joined and fixed to the upper surface of the second cylinder 6. These bearings 15, 1
A lower end portion of the shaft 8 and an upper portion of the second eccentric shaft portion 9b are rotatably supported on the shaft 6. A rotor 17 constituting the electric motor unit 3 is press-fitted and fixed to a portion of the shaft 8 protruding from the main bearing 16 so that the shaft 8 and the shaft 8 are aligned with each other.

The rotor 17 is provided with a permanent magnet therein, and is housed inside a cylindrical stator 18 fixed inside the hermetically sealed case 1 in an eccentric manner as described later. ing. This stator 18 has a power supply unit 1
A DC voltage is supplied from 9. That is, the electric motor unit 3 is a brushless DC electric motor unit.

FIG. 1 shows the positional relationship between the rotor 17 and the stator 18. The rotor 17 is eccentrically provided with respect to the stator 18 at one end side in the radial direction. That is, the above-mentioned blur shown by the arrow in the figure with the shaft center of the shaft 8 as the center.
When the position of 0 degree in the circumferential direction from the blade 11, which is the center of the blade 11, is the origin of the rotation angle of the rotor 17,
At the origin, the outer circumference of the rotor 17 and the stator 1
The distance δ1 from the inner diameter of 8 is 180 in the circumferential direction from the origin.
The positions of the rotor 17 and the stator 18 are set so as to be smaller than the interval .delta.2 at the position of degrees. In this embodiment, the interval Δ1 is set to the minimum and the interval Δ2 is set to the maximum.

FIG. 2 shows the relationship between the gap imbalance between the intervals δ1 and δ2 and the radial force generated in the rotor 17. As you can see from this graph, (δ2-δ1)
The larger the gap imbalance shown by, that is, the smaller δ1, the more the rotor 17 and the stator 1
It can be seen that the magnetic force generated between No. 8 and No. 8 increases.

According to the multi-cylinder rotary compressor having such a structure, when the electric motor part 3 is operated to rotate the shaft 8 together with the rotor 17, the first and second eccentric shafts of the shaft 8 are rotated. The portions 9a and 9b are pressed by the blade 11 via the roller 7. That is, when the center of the blade 11 is the origin, the blade 11 rotates while being pressed in a direction shifted by 180 degrees in the circumferential direction from the origin.

However, the shaft 8 is the rotor 1
7, the blade 11 is displaced in advance toward the origin of the blade 11, and the rotor 17 is provided with a permanent magnet so that the magnetic force of the permanent magnet attracts the blade 11 toward the origin. Therefore, when the shaft 8 is pressed by the blade 11 to rotate, the rotation center of the shaft 8 is displaced toward the center of the stator 18 in that state, so that the shaft 8 and the upper portion of the main bearing 16 in the pressing direction are The increase of the bearing reaction force during is reduced.

As a result, the oil film thickness between the shaft 8 and the main bearing 16 is prevented from being reduced, so that the supporting state of the shaft 8 by the main bearing 16 is prevented from being impaired.

FIGS. 4 (a) and 4 (b) are graphs in which the loci of the shaft center of the shaft 8 in the upper portion of the main bearing 16 of the prior art and the present invention are measured. In the conventional case shown in FIG.
It can be seen that the locus A of the shaft 8 is largely deviated in the anti-blade 11 direction. On the other hand, in the case of the present invention shown in FIG. 4B, it was confirmed that the trajectory B of the shaft 8 has a smaller deviation in the anti-blade 11 direction than in the conventional case.

As described above, by providing the rotor 17 of the electric motor unit 3 with the permanent magnet, the brushless DC electric motor unit is formed, and the rotor 17 together with the shaft 8 is blade 11.
By preliminarily displacing in the direction of, the shaft 8 can be prevented from being excessively displaced in the direction opposite to the blade 11. Thereby, the reaction force between the shaft 8 and the main bearing 16 can be prevented from increasing, so that the supporting performance of the shaft 8 by the main bearing 16 can be favorably maintained.

[0021]

As described above, according to the present invention, the plurality of cylinders, the rollers provided in the cylinders, and the tips of the rollers are elastically pressed against the outer peripheral surface of the rollers. A blade, a shaft having an eccentric shaft portion for eccentrically rotating the roller, rotatably supported by bearings arranged above and below the cylinder, and attached with the shaft center aligned with the shaft. A rotor and a stator containing the rotor therein, the motor comprising a brushless DC motor having a permanent magnet on the rotor, and the shaft center of the shaft. The gap between the inner diameter of the stator and the outer diameter of the rotor at a position of 0 degrees from the blade in the circumferential direction is smaller than the clearance at the position of 180 degrees in the circumferential direction from the blade. It is characterized by having done.

Therefore, due to the magnetic force of the permanent magnet provided on the rotor and the displacement of the shaft in the blade direction in advance, when the shaft is rotated, the shaft moves in the anti-blade direction. Since it is possible to prevent excessive displacement, it is possible to prevent the bearing reaction force of the shaft from increasing and impairing its supporting state.

[Brief description of drawings]

FIG. 1 is a sectional view showing an eccentric state of a rotor with respect to a stator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a relationship between magnetic force and a gap imbalance between a stator and a rotor.

FIG. 3 is a sectional view of the entire structure of the same compressor.

FIG. 4A is a diagram in which a trajectory of a shaft in a conventional compressor is measured, and FIG. 4B is a diagram in which a trajectory of a shaft in the compressor of the present invention is measured.

[Explanation of symbols]

3 ... Electric motor part, 5, 6 ... Cylinder, 7 ... Roller, 8 ... Shaft, 9a, 9b ... Eccentric shaft part, 11 ... Blade, 17
… Rotor, 18… stator.

Claims (2)

[Claims] 1. A plurality of cylinders, a roller provided in the cylinder, a blade provided with its tip elastically pressed against the outer peripheral surface of the roller, and the roller. A shaft rotatably supported by bearings arranged above and below the cylinder having an eccentric shaft portion for eccentric rotation, a rotor attached with the shaft center aligned with the shaft, and the rotor An electric motor unit including a stator housed in the rotor, the electric motor unit including a brushless DC electric motor unit having a permanent magnet on the rotor, and a circumferential direction from the blade about the axis of the shaft. The multi-cylinder type is characterized in that the gap between the inner diameter of the stator and the outer diameter of the rotor at the 0 degree position is smaller than the gap at the 180 degree position in the circumferential direction from the blade. Rotary compressor. 2. The multi-cylinder rotary compressor according to claim 1, wherein the clearance at the 0-degree position is minimized and the clearance at the 180-degree position is maximized.