JPS601385A - Balancer for compressor - Google Patents

Abstract

PURPOSE:To reduce the deflection of a rotary shaft caused by counterweights attached to both the ends of an electric motive section, by making the counterweights lighter than such weight as to balance with the unbalancing force of a compressing section. CONSTITUTION:Counterweights 17, 18, which are attached with a rotational angle difference of 180 deg. to both the upper and lower ends of the rotor 8 of an electric motive section 2, are made lighter than such weight as to balance with the unbalancing force of the rolling piston 11 and eccentric portion of a rotary compressing section 4. As a result, the centrifugal force does not become strong even if the rotational frequency of the electric motive section 2 exceeds a rated value. The bending moment to deflect a rotary shaft 3 is thus kept small.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to compressors, and particularly to a balance device for a compressor operated at a rated speed or higher.

(b) Prior art The conventional example will be explained based on FIG.
This is a rotary compressor in which a rotary compression element (4) driven through a rotary compressor (4) and a rotary compressor (4) are arranged in a closed container (5). The electric element (2) is composed of a stator (7) containing a winding (6) and a rotor (8) provided within the stator. The rotary compression element (4) is connected to the cylinder (9), the eccentric part of the rotating shaft (3) (the rolling piston Ql that rotates inside the cylinder (9) by 101), and the rolling piston that contacts the inside of the cylinder (9). It is composed of a -J'-levane Q2+ that divides the cylinder into a high-pressure area and a low-pressure area, and a bearing (J3) (14) that closes the opening of the cylinder (9). 0ω (16) is a balance weight that balances the unbalanced force generated by the rotation of the rolling piston 0υ of the rotary compression element (4) and the eccentric part QO), and this balance weight is 8) are attached to both the upper and lower ends of the unit with a rotation angle shifted by 180°.

In this compressor balance device, when the rotary compression element (4) is driven by the electric element (2), the unbalanced force generated by the 5-rotation movement is absorbed and compressed by the electric element (2). ) is balanced by the unbalanced force of balance weights α51 (16) attached to both the upper and lower ends of the rotor (8).

Shikajina 7! ! - et al., balance weight (''ω(16)
The centrifugal force increases in proportion to the square of the rotational speed, and the amount of deflection of the rotating shaft (3) increases in proportion to the cube of the distance from the fixed part on which the centrifugal force acts.

Therefore, when the rotation speed of the electric element (2) exceeds the rated rotation speed, the balance weight H5) attached to the upper end of the rotor (8) will deflect the rotating shaft (3) due to the centrifugal force of this balance weight. Due to the rapid increase in size, contact between the stator (7) and rotor (8) and the rotating shaft (3) and bearing (
13 (14).

0→Object of the Invention In view of the above points, an object of the present invention is to reduce the deflection of the rotating shaft due to the bending moment generated by the centrifugal force of the balance weight.

B) Structure of the Invention The basic structure of this invention is that an electric element that rotates at a rated rotation speed or higher and a compression element that is driven by this electric element via a rotating shaft are placed in a closed container, and the electric element is The balance weights attached to both ends are lighter than the weight that balances the unbalanced force of the compression element.

A balance device for a compressor with this configuration reduces the weight of balance weights attached to both ends of the electric element to balance the unbalanced force of the compression element, and uses the centrifugal force of the balance weights that rotate at more than the rated rotation speed. This is to reduce the deflection of the rotating shaft.

(7ffiU) EXAMPLE The present invention will be explained below based on the example shown in FIG.

The same parts or equivalent parts as in the conventional example shown in FIG. 1 are denoted by the same reference numerals, and the explanation thereof will be omitted.

The difference from the conventional example is 3011z to 12 due to inverter etc.
The rolling piston of the compression element (4) rotates the balance weight 0η0 (to), which is attached to the upper and lower ends of the rotor (8) of the electric element (2) with a rotation angle of 180°, which is operated at a frequency of 011z. This is because the weight is lighter than the weight that balances the unbalanced force between Ql) and the eccentric portion α0).

In the compressor balance device configured in this way,
A rotary compression element (4) driven by an electric element (2) operated at a frequency of 301 (z~120Hz) moves inside the cylinder (9) by an eccentric part a of the rotating shaft (3) [by a rolling piston aυ rotating with the eccentric part a of the rotating shaft (3). An unbalanced force occurs during suction Φ compression.The balance weights Qη0 attached to both the upper and lower ends of the rotor (8) are lighter than the weight that balances the unbalanced force of the rotary compression element (4). , electric element (
When the rotational speed (2) exceeds the rated rotational speed, the centrifugal force is prevented from increasing and the bending moment that deflects the rotating shaft (3) is reduced. Further, the balance weights (17) + 18) can suppress the occurrence of vibration due to unbalanced dynamic balance to a small level unless the difference in unbalanced force with the rotary compression element (4) becomes extremely large.

Figure 3 shows the change in the deflection state of the upper end of the rotating shaft with respect to the change in power frequency when the weight of the balance weight W attached to the upper end of the rotor is changed, and the diameter of the rotating shaft is 19 .2mm.

From this figure, it can be seen that as the power supply frequency becomes higher, the difference in the amount of deflection due to the difference in the weight of the balance weight W becomes larger.

In the above description, a rotary compressor is used, but it goes without saying that the same effect can be achieved even when a reciprocating compressor is used.

(f) Effects of the Invention The balance device of this invention makes the balance weight for the Dlil EM, an electric element that rotates at a speed higher than the rated rotation speed, lighter than the weight that balances the unbalanced force of the compression element.
Since the centrifugal force generated by this balance weight is reduced, even if the rotation speed of the balance weight exceeds the rated rotation speed, the deflection of the rotating shaft due to this balance weight is reduced, and the stator of the electric element This prevents contact between the rotor and the rotor and galling between the rotating shaft and the bearing.

[Brief explanation of the drawing]

8r! Figure 1 is a sectional view of a conventional rotary compressor, Figure 2 is a sectional view of a rotary compressor showing an embodiment of the present invention, and Figure 3 is a characteristic diagram showing changes in deflection of the rotating shaft with respect to frequency. Yes, (1)...rotary compressor, (2)...electric element,
(3)... Rotating shaft, (4)... Rotating compression element,
(5)...Airtight container, (fη(+8)...Balance weight. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a compressor in which an electric element that rotates at a rated rotation speed or higher and a compression element that is driven by the electric element via a rotating shaft are arranged in a closed container, balance weights attached to both ends of the electric element are used. A balance device for a compressor characterized by having a weight lighter than that which balances the unbalanced force of a compression element.