JP2004218471A - Hermetic electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of efficiency of refrigeration cycle and reliability of a compressor mechanism part caused by violently agitating cooling medium gas and oil and discharging oil together with cooling medium gas to outside of a sealed vessel by rotation of a balance weight installed on a rotor. <P>SOLUTION: Since area of an end surface 14a of the balance weight 14 facing a rotation direction can be made very small by shaping the balance weight 14 in a roughly semicircular arc shape having an outer diameter concentric with the rotor 13 and an inner diameter eccentric in relation to a rotor rotation direction, cooling medium gas and oil are not violently agitated. Consequently, oil discharged to outside of the sealed vessel 1 can be reduced and input and noise can be greatly reduced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hermetic electric compressor used for an air conditioner or the like.
[0002]
[Prior art]
As shown in FIG. 4, the hermetic electric compressor has a compression mechanism 2 and an electric motor 3 for driving the compression mechanism 2 inside a closed container 1. The compression mechanism 2 includes a crankshaft 4 for transmitting the rotational force of the electric motor 3 to the compression mechanism 2, a piston 6 rotatably fitted to an eccentric shaft 5 of the crankshaft 4, and a piston 6. A cylinder 7 having a cylindrical air chamber; a vane 8 slidably fitted in a groove provided in the cylinder 7; and a spring 9 for pressing the tip of the vane 8 against the piston 7. , A main bearing 10 and a sub bearing 11 that support the crankshaft 4.
[0003]
With the above configuration, when the electric motor section 3 is driven, the refrigerant gas sucked from the suction hole (not shown) of the compression mechanism section 2 is compressed by the compression mechanism section 2, and the discharge hole provided in the main bearing 10. (Not shown) is discharged to the compression mechanism side space 18 surrounded by the electric motor unit 3 and the main bearing 10 inside the closed casing 1, passes through the gap of the electric motor unit 3, and passes through the discharge pipe to the outside of the closed casing 1. To the refrigeration cycle.
[0004]
On the other hand, an oil reservoir 16 is provided at the bottom of the closed casing 1. Oil is pumped up by a pump device (not shown) provided inside the crankshaft 4, and lubricates each sliding portion of the compression mechanism 2. After that, most of the oil is discharged from the oil discharge hole 17 between the main bearing 10 and the crankshaft 4 and returns to the oil reservoir 16 again.
[0005]
The electric motor unit 3 includes a stator 12 and a rotor 13, and the upper and lower ends of the rotor 13 apply unbalanced forces generated by rotation of the eccentric shaft 5 of the crankshaft 4 and the piston 6. To cancel, balance weights 14 and 15 are provided.
[0006]
As shown in FIG. 5, a conventional balance weight of this type is generally used in which both outer and inner diameters are formed in a semicircular shape concentric with the rotor 13 at both ends of the rotor 13. . In particular, the balance weight 14 provided on the compression mechanism side needs to be larger than the balance weight 15 provided on the non-compression mechanism side in order to balance the balance weight.
[0007]
Furthermore, in a single-cylinder rotary compressor in which the suction volume of the compression mechanism is relatively large, the eccentric shaft 5 and the piston 6 are relatively large in size, so that the unbalanced force is also large. The weights 14 and 15 also had to be very large.
[0008]
However, in the structure in which the semicircular balance weight is provided as described above, the refrigerant gas discharged from the main bearing 10 and the oil discharged from the oil discharge hole 17 are disposed at the end face 14a facing the rotation direction of the balance weight. Are vigorously stirred in the compression mechanism side space 18. As a result, the oil does not fall into the oil sump 16 but forms a mist, and is discharged to the outside of the closed container 1 together with the refrigerant gas. As a result, the efficiency of a refrigerating cycle (not shown) to which the compressor is connected is reduced, or the oil level of the oil reservoir 16 is reduced, and the reliability of the compression mechanism 2 is reduced due to insufficient lubrication oil. Was the cause.
[0009]
Furthermore, the stirring of the refrigerant gas causes problems such as an increase in input due to resistance when the balance weight ends press and move the refrigerant and the like, and an increase in noise due to wind noise.
[0010]
As a conventional technology for solving these problems, there is known a technology in which a balance weight is formed by changing the shape of an inner diameter to a circular outer diameter (for example, Patent Document 1). FIG. 6 shows a conventional balance weight described in Patent Document 1.
[0011]
In FIG. 6, balance weights 14 and 15 are attached to both ends of a rotor 13. In these shapes, the inner diameter and the outer diameter are eccentric, and their centers of gravity are formed so that the unbalance force due to the rotation is canceled.
[0012]
With the above configuration, even if the balance weights 14 and 15 rotate, the refrigerant gas and the oil are not vigorously stirred in the compression mechanism side space 18 and the oil discharged to the outside of the closed container 1 is reduced. be able to. Also, an increase in input due to fluid resistance and an increase in noise due to wind noise can be significantly suppressed.
[0013]
[Patent Document 1]
JP-A-57-51178 (FIGS. 4 and 5)
[0014]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, the balance weights 14 and 15 have a shape in which the balance eight is added to the opposite side to the center of gravity in the radial direction, and the outer diameter of the balance eight is generally substantially equal to the outer diameter of the rotor 13. Due to the restriction of being smaller than the diameter, the height of the balance weights 14 and 15 themselves had to be increased in order to balance.
[0015]
As a result, in particular, when the conventional balance weight 14 is installed on the compression mechanism 2 side of the rotor 13, the distance between the compression mechanism 2 and the electric motor 3 must be increased, thereby increasing the crankshaft. 4, the whirling of the compressor 4 itself may increase, and the vibration of the compressor itself may increase, and further, the reliability may decrease due to the increase in the load on the main bearing 10.
[0016]
In addition, there is a problem that the material cost increases as the balance weight is increased, resulting in an increase in cost.
[0017]
The present invention is to solve such a conventional problem, and suppresses the stirring of the refrigerant gas by the balance weight installed in the rotor, reduces oil discharge to the outside of the compressor, and achieves high efficiency and low noise. It is an object of the present invention to provide a highly reliable hermetic electric compressor.
[0018]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention is such that a balance weight provided at an end of a rotor of a motor section has an end face of a balance weight facing a rotating direction of the rotor in a shape having a small fluid resistance. .
[0019]
With the above configuration, it is possible to suppress the stirring of the refrigerant gas and the oil mist inside the closed container due to the rotation of the balance weight without substantially increasing the material cost of the balance weight, and as a result, the oil discharge to the outside of the compressor , And a hermetic electric compressor with high efficiency, low noise and high reliability can be obtained.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
(Embodiment 1)
FIG. 1 is a perspective view of a balance weight according to Embodiment 1 of the present invention. In FIG. 1, the same components as those of the conventional technique shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.
[0022]
In FIG. 1, the shape of the balance weight 14 is a substantially semi-circular shape having an outer diameter concentric with the rotor 13 and an inner diameter eccentric with respect to the rotor rotation direction. The center of gravity of the balance weight 14 (reference numeral G in the drawing) is set at a position where the unbalance force due to the rotation is canceled.
[0023]
According to the above configuration, the area of the end face 14a of the balance weight 14 facing the rotating direction of the rotor 13 becomes very small. As a result, the refrigerant gas and the oil are not vigorously stirred in the compression mechanism side space 18. In addition, oil discharged to the outside of the closed container 1 can be reduced. Also, an increase in input due to fluid resistance and an increase in noise due to wind noise can be significantly suppressed.
[0024]
In the first embodiment, only the balance weight 14 on the compression mechanism 2 side of the rotor 13 has been described. However, the balance weight 15 on the anti-compression mechanism side has the same configuration as described above. In the space 19 on the side opposite to the compression mechanism, further effects can be obtained by the same operation as described above. Although the end face 14a is a plane having a very small area, a similar effect can be obtained even when the end face 14a is a smooth curved surface having a certain area.
[0025]
(Embodiment 2)
FIG. 2 is a perspective view of a balance weight according to Embodiment 2 of the present invention. In FIG. 2, the same components as those of the conventional technique shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.
[0026]
In FIG. 2, the shape of the balance weight 14 is a shape whose height is gradually increased in the rotation direction of the rotor 13. The center of gravity of the balance weight 14 (reference numeral G in the drawing) is set at a position where the unbalance force due to the rotation is canceled.
[0027]
With the above configuration, even when the balance weight 14 rotates, the refrigerant gas and the oil are not violently agitated in the compression mechanism side space 18 and the oil discharged to the outside of the closed container 1 can be reduced. it can. Also, an increase in input due to fluid resistance and an increase in noise due to wind noise can be significantly suppressed.
[0028]
In the second embodiment, only the balance weight 14 on the compression mechanism 2 side of the rotor 13 has been described. However, the balance weight 15 on the anti-compression mechanism side has the same configuration as described above. In the space 19 on the side opposite to the compression mechanism, further effects can be obtained by the same operation as described above.
[0029]
(Embodiment 3)
FIG. 3 is a perspective view of a balance weight according to Embodiment 3 of the present invention. In FIG. 3, the same components as those of the conventional technique shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.
[0030]
In FIG. 3, the shape of the balance weight 14 is tapered so that the inner diameter surface 14b expands toward the end. The center of gravity of the balance weight 14 (reference numeral G in the drawing) is set at a position where the unbalance force due to the rotation is canceled.
[0031]
According to the above configuration, in addition to the operation and effect described in the first or second embodiment, when the oil discharged from the oil discharge hole 17 returns to the oil reservoir 16, the inner diameter surface 14b is tapered. The centrifugal force acts on the oil adhering to the surface 14b, and the oil easily returns to the bottom. As a result, a further effect of reducing oil discharge can be obtained. In this configuration, if the radial thickness of the balance weight is particularly thin at the front end in the rotation direction and thick at the rear end, the oil caught on the inner surface of the balance weight becomes difficult to escape from the rear end of the balance weight. The shape has an effect that oil can be discharged in the axial direction by centrifugal force.
[0032]
In the above-described embodiment, the thickness and the height of the balance weight gradually increase from the front end to the rear end in the rotation direction, but the balance weight gradually increases in a predetermined range from the front end to the rear end in the rotation direction. The same effect can be obtained even when the thickness is constant.
[0033]
Further, in addition to the above-described embodiments, the same applies to a case where the tip portion has a smooth curved shape such as a streamline type.
[0034]
【The invention's effect】
As is clear from the above, the present invention provides a balance weight installed at an end of a rotor of an electric motor unit, wherein the shape of the end of the balance weight facing in the rotation direction of the rotor is a shape having a small fluid resistance. According to this configuration, it is possible to suppress the stirring of the refrigerant gas and the oil mist inside the closed vessel due to the rotation of the balance weight without substantially increasing the material cost of the balance weight. Oil discharge to the engine can be reduced. Further, an increase in input due to rotational resistance and an increase in noise due to wind noise can be significantly suppressed.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a hermetic electric compressor showing a first embodiment of the present invention; FIG. 2 is a perspective view of a main part showing a second embodiment of the present invention; FIG. FIG. 4 is a longitudinal sectional view of a hermetic electric compressor. FIG. 5 is a perspective view of a main part showing a conventional embodiment. FIG. 6 is a main part perspective view showing another conventional embodiment. Part perspective view [Description of reference numerals]
REFERENCE SIGNS LIST 1 sealed container 2 compression mechanism 3 motor 13 rotor 14 balance weight on compression mechanism 15 balance weight on anti-compression mechanism 16 oil reservoir 18 compression mechanism side space 19 anti-compression mechanism side space

Claims (4)

A hermetic electric compressor in which a compression mechanism and an electric motor driving the compression mechanism are housed inside a closed container having an oil reservoir at a bottom, the surface facing a rotating direction of a balance weight for correcting an unbalanced force. , Mainly comprising a surface disposed at a predetermined angle with respect to the rotation direction or a smooth curved surface. 2. The hermetic electric compressor according to claim 1, wherein the balance weight disposed at a rotor end of the electric motor has a minimum radial thickness at a tip end in the rotor rotation direction, and at least from a tip end in the rotation direction. 3. A hermetic electric compressor characterized in that the radial thickness gradually increases toward the rear end in the rotation direction within a certain range. 2. The hermetic electric compressor according to claim 1, wherein the balance weight disposed at an end of the rotor of the electric motor has a minimum axial height at a tip end in the rotation direction of the rotor, and at least from a tip end in the rotation direction. A hermetic electric compressor characterized in that the axial height gradually increases toward the rear end in the rotation direction within a certain range. 4. The hermetic electric compressor according to claim 2, wherein an inner diameter surface of the balance weight is a tapered surface inclined from a rotor end to a rotor outer peripheral side toward a balance weight axial end. Features a hermetic electric compressor.

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