JP3519224B2 - Hermetic compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an HFC refrigerant as a refrigerant used in a hermetic compressor constituting a refrigerating cycle of an air conditioner, and more particularly to an improvement of a structure for mounting a hermetic terminal in a hermetic case.

[0002]

2. Description of the Related Art For example, in a refrigeration cycle of an air conditioner, a CFC (chlorofluorocarbon) 12 (called R12) refrigerant or an HCF has conventionally been used as a refrigerant.
A C (hydrochlorofluorocarbon) 22 (referred to as R22) refrigerant has been used, but it is said that there is a strong possibility of destroying the ozone layer.

Therefore, there has been a demand for new refrigerants to replace these fluorocarbons, and as a result of promoting the development of new alternative substances centered on the fact that there is no ozone layer depletion, HFC (hydrofluorocarbon) refrigerants containing no chlorine atom have been developed. It was adopted.

[0004]

By the way, among the HFC refrigerants which are the alternative refrigerants, the mixed refrigerant R41 is used.
The theoretical refrigerating capacity of 0A is larger than that of the refrigerant used conventionally. From this, when the HFC mixed refrigerant is used in the refrigeration cycle of the air conditioner, the working pressure becomes about 1.5 times higher than that of the conventional R22, and the pressure resistance design of all the components must be reviewed.

FIG. 7 shows a part of a conventional hermetic compressor. The motor part b is housed in the upper part inside the closed case a,
The compression mechanism portion c, which is omitted except for a part, is accommodated in the lower portion. The electric motor part b and the compression mechanism part c are connected by a rotary shaft d.

The hermetically sealed case a has a case body e formed of a cylindrical body having an opening at least at its upper end, and is fitted into the opening of the case body e, and is fixed to the case body by welding means so that the opening is formed. It is composed of a lid f to be closed.

Further, the lid body f is integrally provided with a fitting portion f1 fitted to the peripheral surface of the end portion of the case body e through an R portion in a direction orthogonal to the axial direction of the case body e. It is composed of a closed portion f2, and the closed portion has a flat surface.

A sealed terminal g is attached to the closed portion f2 of the lid body f. A lead wire (not shown) is provided between the sealed terminal g and the electric motor part b in the closed case a, and the sealed terminal and the electric motor part are electrically connected via the lead wire.

In the compressor of this type, if the above HFC mixed refrigerant is used, the closed case a may be deformed by receiving the internal pressure from a place where the working pressure is high. However, since the case body e is fitted with the stator h that constitutes the electric motor section b and the support frame i that constitutes the compression mechanism section c and the like, the case body e does not significantly deform even if it receives internal pressure. Does not happen.

However, only the sealing terminal g and the discharge pipe j are attached to the lid body f as a member constituting the same sealed case a, and these members suppress deformation of the lid body even if they receive internal pressure. It cannot be. That is, the lid f is easily deformed by the internal pressure.

As schematically shown in FIG. 8, the closed portion f2 of the lid f, in particular, cannot hold a flat surface, and is bulged and deformed so that the central portion thereof projects most. Due to the influence of this deformation, a remarkable stress concentration appears in the mounting portion k of the sealed terminal g having a large opening area.

Since stress is repeatedly generated in the mounting portion k of the sealed terminal g each time the compressor is started or stopped and the pressure condition changes, there is a risk of fatigue failure in this portion.

If the wall thickness of the lid body f is increased together with the case body e, such a problem will not occur, but
This time, the material cost will increase, the workability will decrease, and the man-hour will increase, leading to an increase in cost.

The present invention has been made based on the above circumstances, and an object of the present invention is to cope with the use of a refrigerant having a high working pressure, so that sufficient pressure resistance can be achieved without increasing the thickness of the hermetically sealed case. Has high stability,
In addition, it is an object of the present invention to provide a hermetic compressor that can keep the cost low.

[0015]

In order to satisfy the above object, the hermetic compressor of the present invention is a hermetic compressor which constitutes a refrigeration cycle using an HFC refrigerant, and is a cylindrical body whose both ends are closed. And a sealed case in which the electric motor section and the compressor section are housed, a spherical portion formed in at least a part of the sealed case, and a mounting portion opened in the spherical portion of the sealed case. And a hermetically sealed terminal fitted in the opening of the mounting portion with airtightness and electrically connected to the electric motor portion , wherein the spherical portion is
Set the spherical radius to 50-100% of the inner diameter of the closed case cylinder.
To be done.

[0016]

[0017]

Further, in the hermetically sealed terminal, the cap portion constituting the hermetically sealed terminal is formed in a spherical shape . In addition, the key
In the cap portion , the spherical radius is the same as the spherical radius of the spherical portion,
Alternatively, the size is set to be smaller than that.

[0019] adopting a means for solving the problems of the above-mentioned
As a result, with the deformation of the hermetically sealed case, the stress received by the hermetically sealed terminal mounting portion is reduced, and the rigidity strength of this portion is improved. Therefore, even if a refrigerant having a high condensation pressure or evaporation pressure is used, a sufficient pressure resistance effect can be obtained, and it is not necessary to increase the plate thickness of the closed case. Can be thin.

[0020] Although the pressure with high R410A refrigerant as compared with R22 refrigerant, which is conventionally used, can hold the mounting strength of the conventional even sealed terminal a sealed casing having a wall thickness equivalent.

Further, by setting the dimension of the spherical surface portion, the optimum external dimension in which the protrusion of the spherical surface portion is suppressed as much as possible is obtained. That is, the expansion of the installation space is prevented and the interference with other parts is eliminated.

The strength of the mounting portion for the sealed terminal, which is said to be the weakest in terms of the case structure, can be enhanced. Furthermore
In addition, the thickness of the cap is thinner than the thickness of the closed case,
Originally, the strength cannot be maintained, but by setting the dimensions as described above, the strength can be enhanced without increasing the plate thickness of the cap portion.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a hermetic compressor according to the present invention will be described below with reference to the drawings. This hermetic compressor constitutes, for example, a refrigeration cycle of an air conditioner. The refrigerant used in the refrigeration cycle, it is premised condensing pressure and evaporating pressure, compared to conventional R22 refrigerant is higher HFC refrigerant, among the R
410A is used.

This R410A refrigerant is a pseudo-azeotropic mixed refrigerant in which difluoromethane (R32) and pentafluoroethane (R125) are mixed at a ratio of 50% (weight ratio), and the pressure loss is small and the heat Since it has high conductivity, it has optimum characteristics for an air conditioner.

However, this R410A refrigerant has a higher condensing pressure and evaporating pressure than the conventionally used R22 refrigerant, and is higher than other HFC mixed refrigerants. Therefore, of the HFC mixed refrigerants, the R410A refrigerant is particularly called a high pressure refrigerant.

Reference numeral 1 shown in FIG. 1 denotes a closed case which will be described later. In this closed case 1, the electric compressor main body 2
Is housed. The electric compressor body 2 is configured by connecting a motor shaft 4 on the upper side of a rotating shaft 3 oriented in the vertical direction and a compression mechanism part 5 on the lower side.

An oil reservoir 6 for containing lubricating oil is formed on the inner bottom of the closed case 1, and a part of the compression mechanism 5 is immersed therein. The electric motor unit 4 is provided with a stator 7 fixed to the inner wall of the hermetically sealed case 1, and a rotor that is arranged with a small gap between the stator 7 and the inner peripheral surface of the stator, and is fitted to the rotary shaft 3. 8 and.

The compression mechanism portion 5 is provided with upper and lower two-stage cylinder chambers 9a and 9b, and eccentric rollers 10a and 10b are eccentrically rotatably housed in the respective cylinder chambers. Make up.

Suction pipes 11a and 11b are connected to the cylinder chambers 9a and 9b of the compression mechanism 5, and an evaporator (not shown) that constitutes a refrigerating cycle (internal heat) through a gas-liquid separator 12 is connected. (Exchanger).

Next, the closed case 1 will be described in detail. The hermetically sealed case includes a case body 13 that is a cylindrical body having a bottom portion at the lower end and an upper end portion that is open, and a lid body 14 that closes the upper end opening portion of the case body.

Both the case body 13 and the lid 14 are
Although R410A , which is a high-pressure refrigerant, is used as the refrigerant, the plate thickness may be the same as the conventional one. The stator 7 that constitutes the electric motor unit 4 and the support frame 5a that constitutes the compression mechanism unit 5 are fitted to the case body 13, and the lid 1
The discharge pipe 16 and the hermetically sealed terminal 17 are attached to 4 in the same manner as in the prior art.

The lid 14 is fitted into the upper end opening of the case body 13 and is welded along the fitting edge of the case body. It is also formed by the closing portion 15 which is integrally provided continuously and is orthogonal to the axial direction of the case body 13 and closes the opening of the case body.

However, since the closing part 15 is formed in a spherical shape having its center on the axial center of the case body 13, it will be referred to as a spherical part hereinafter. The spherical radius R of the spherical portion 15 is 50 to 1 of the inner diameter Rc of the case body 13.
It must be set in the range of 00%. (0.5 Rc
≦ R ≦ Rc) If the inner diameter is set to be smaller than this range, higher strength can be obtained, but it is largely protruded to make molding difficult, and even if molding is possible, the outer shape of the compressor becomes large.

Further, if the radius is set to be larger than this range, the shape becomes almost flat and the difference from the conventional one cannot be maintained. Therefore, the above range does not have much protrusion and can maintain high strength.

The discharge pipe 16 provided through almost the center of the spherical portion 15 has a lower end opened at an upper portion of the electric motor unit 4, and the other end not shown constitutes a refrigerating cycle. (Communication with the outdoor heat exchanger).

Further, a mounting portion 18 composed of an opening is provided at a predetermined portion of the spherical surface portion 15, and the above-mentioned sealed terminal 17 is inserted therein, and is fixedly mounted by, for example, projection welding means. Naturally, highly accurate welding having airtightness is performed.

The mounting means of the sealed terminal 17 will be further explained. Since the lid spherical surface portion 15 is formed in a spherical shape,
Even if the mounting portion 18 is opened, this edge portion is on the same plane and is almost circular.

Therefore, the sealed terminal 17 may be formed by fitting an ordinary commercially available product which has been conventionally used as it is into the opening of the mounting portion 18 and welding it. In particular, a special sealed terminal having a curved mounting portion is absolutely necessary. There is no.

The sealed terminal 17 is covered by a cover body 19 attached to the sealed case 1. From this,
Even if raindrops are applied, the sealed terminal 17 will not get wet, and no electric leakage will occur.

Then, the sealed terminal 17 is connected to the external commercial power source.
When the electric motor unit 4 is energized via the rotary shaft 3, the rotary shaft 3 is rotationally driven, whereby the eccentric rollers 10a and 10b rotate eccentrically in the cylinder chambers 9a and 9b. As a result, R410A, which is an HFC mixed refrigerant, is passed from the suction pipes 11a and 11b to the respective cylinder chambers via the gas-liquid separator 12.
Gas is inhaled.

The eccentric rollers 10a and 10b are connected to the cylinder chamber 9
The space capacity of the cylinder chamber is maximized by rolling contact with a predetermined portion of the inner peripheral surfaces of a and 9b. Refrigerant gas is drawn into each suction pipe 11a, 1
The cylinder chambers 9a, 9b are guided from 1b and filled.

With the eccentric rotation of the eccentric rollers 10a and 10b, the rolling contact position with the inner peripheral surfaces of the cylinder chambers 9a and 9b moves, and the volume of the moving cylinder chamber decreases. That is, the gas previously introduced into the cylinder chamber is gradually compressed.

When the rotary shaft 3 is continuously rotated, the volumes of the cylinder chambers 9a and 9b on the moving side further decrease, the gas introduced therein is compressed, and when the pressure rises to a predetermined pressure, high pressure gas is released from the cylinder chamber. It is discharged and filled in the closed case 1. Then, the liquid is discharged from the discharge pipe 16 above the closed case 1.

As shown in FIG. 2, the closed case 1 is deformed from the two-dot chain line shown in FIG.
That is, while the high-pressure refrigerant R410A is used in the refrigeration cycle, the plate thickness of the closed case 1 is the same as the conventional one, so the closed case is deformed to some extent.

However, the case body 13 which constitutes the closed case 1 is fitted with the stator 7 of the electric motor section 4 and the support frame 5a of the compression mechanism section 5, and at the bottom. Since the lubricating oil reservoir 6 is formed, it is hardly deformed. On the other hand, the lid 14 has
Since only the discharge pipe 16 and the sealed terminal 17 are provided and neither of them is a member for suppressing the deformation of the lid body, the lid body is deformed.

It is also the fitting portion 14a that constitutes the lid body 14.
Since it is connected to the case body 13, the deformation is not so great, but since the spherical surface portion 15 has no relation to the deformation suppressing member, the deformation is concentrated. It should be noted that the spherical portion 15 is extremely deformed because it is schematically shown in the same drawing, but it is actually a slight deformation.

In the deformed state, the spherical shape of the spherical surface portion 15 does not change, and the spherical surface portion bulges outward as a whole and almost uniformly. The force applied to the sealed terminal 17 is only the force that simply pushes it out.

Therefore, unlike the conventional case, stress concentration is hardly generated in the mounting portion 18 of the sealed terminal 17, and even if it is generated, it is very slight and does not cause fatigue failure at all.

The characteristics of the prior art and the present invention were calculated based on the finite element method, and the results are shown in FIG. A dashed-dotted line change A in the figure shows the relationship between the internal pressure of the sealed case of the conventional structure and the stress applied to the mounting portion of the sealed terminal, and a solid line change B of the figure shows the internal pressure of the sealed case of the present invention and the sealed terminal. The relationship with the stress applied to the mounting portion is shown.

Regarding the basis for calculation in the present invention,
The spherical radius R of the spherical surface portion 15 is set to the cylindrical inner diameter R of the case body 13.
It is set to 65% of c. Since plastic deformation is not taken into consideration in this calculation, it differs from the actual stress generated, but both are calculated under the same conditions with a plate thickness of 3.2 mm. As a result, as shown in FIG. 6, the stress (Von-Mises stress) of the mounting portion of the sealed terminal of the present invention can be suppressed to 1/4 or less of the conventional stress.

In this way, the mounting portion 1 for the sealed terminal 17 is mounted.
The stress in the vicinity of 8 can be reduced to a fraction of that of the conventional method, and sufficient pressure resistance can be secured even if a high pressure refrigerant is used. This leads to suppression of cost increase by increasing the case plate thickness. Because the case rigidity is high,
Operation noise during compressor operation is reduced. The sealed terminal can be the same as the conventional one, and no special order is required.

FIG. 3 shows a hermetic compressor which is a horizontal type and has a helical blade type compression mechanism. Closed case 1
The electric motor unit 4A is accommodated on the left side of the drawing in A, and the compression mechanism unit 5A with a part omitted is arranged on the right side.

In the hermetically sealed case 1A, the end on the side of the electric motor 4A is, so to speak, a bottom, and the hermetically sealed terminal 17 is provided here.
Is fixed by means such as welding in the same manner as described above.

However, the spherical portion 15A to which the above-mentioned sealed terminal 17 is fixed is limited to the minimum portion required to mount this sealed terminal. That is, in order to mount the sealed terminal 17, the mounting portion 18A must be opened, and this opening reduces the strength of the surroundings.

In this embodiment, the spherical portion 15A is provided around the mounting portion 18A, which is the minimum portion required to mount the sealed terminal 17. Therefore, the mounting portion 18A
And the strength around it will be enhanced.

FIG. 4 shows an example in which a mounting portion 18B is provided on the peripheral surface of the case body 1B and the sealed terminal 17 is mounted. In this case as well, the spherical portion 15B to which the sealing terminal 17 is fixed is limited to the minimum portion required to mount the sealing terminal to enhance the strength around the mounting portion 18B.

FIG. 5 is characterized in that the hermetically sealed terminal 17A attached to the spherical surface portion 15 constitutes a hermetically sealed terminal and the cap portion 20 directly welded and fixed to the spherical surface portion 15 is formed in a spherical shape.

By forming the cap portion 20 into a spherical shape, the cap portion 20 is uniformly expanded and deformed even when pressure is applied, and stress is not concentrated on the glass welding portion 21 inserted therethrough.
Therefore, breakage of the glass can be prevented.

The plate thickness of the cap portion 20 is the closed case 1
Although it is thinner than the thickness of the (spherical surface portion 15), the rigidity of the cap portion 20 approaches the rigidity of the closed case by making the radius of curvature of the cap portion 20 the same as or smaller than the radius of curvature of the spherical surface portion 15. .

In the above embodiment, the high-pressure refrigerant R410A was used as the refrigerant to be used, but the refrigerant is not limited to this and any kind of refrigerant may be used as long as it contains HFC as a main component. In this case, the wall thickness of the closed case 1 can be reduced as long as the internal pressure of the case is almost the same as when the conventional R22 is used.

[0061]

As described above, according to the present invention , H
A hermetic compressor that constitutes a refrigeration cycle using an FC refrigerant has a spherical portion formed on at least a part of a hermetically sealed case, an attachment portion is opened on this spherical portion, and a hermetically sealed terminal is provided here. Since it is fitted, the stress received by the mounting portion is reduced and the strength is improved. Therefore, even if a refrigerant having a high condensation pressure or evaporation pressure is used, a sufficient pressure resistance effect can be obtained,
It is not necessary to increase the thickness of the closed case, and if the internal pressure of the case is the same as the conventional case, the thickness of the case can be reduced, and in any case, the cost can be prevented from increasing.

[0062]

[0063] Then, because setting the spherical radius of the spherical portion 50 to 100% of the sealed case cylinder inner diameter to obtain the optimal external dimensions that minimizing the ledge of the spherical portion, to prevent the spread of the mounting space, other Eliminate the interference with the parts of.

[0064]

Further, since the cap portion of the sealed terminal has a spherical shape, the strength can be enhanced without increasing the plate thickness of the cap portion. Furthermore, because the spherical radius of the cap is set to be equal to or smaller than the spherical radius of the spherical part, the strength of the cap is enhanced even if the plate thickness of the cap is thinner than that of the closed case. Can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a hermetic compressor showing an embodiment of the present invention.

FIG. 2 is a view for explaining a deformed state of the closed case according to the embodiment.

FIG. 3 is a vertical cross-sectional view of another embodiment in which a hermetic compressor is partially omitted.

FIG. 4 is a partial vertical cross-sectional view of a sealed case according to still another embodiment.

FIG. 5 is a partial vertical cross-sectional view of a sealed case according to still another embodiment.

FIG. 6 is a characteristic diagram of stress of the terminal mounting portion with respect to internal pressure in the structure of the present invention and the conventional structure.

FIG. 7 is a vertical sectional view in which a part of a conventional hermetic compressor is omitted.

FIG. 8 is a diagram illustrating a deformed state of the conventional closed case.

[Explanation of symbols]

4 ... electric motor part, 5 ... Compressor section, 1 ... hermetically sealed case, 15 ... spherical part, 18 ... Mounting part, 17 ... Sealed terminal, 20 ... Cap section.

Claims (3)

(57) [Claims] 1. A hermetic compressor that constitutes a refrigeration cycle using an HFC refrigerant, which is a cylindrical body whose both ends are closed, and in which a motor case and a compressor section are housed. A spherical portion formed on at least a part of the hermetically sealed case, a mounting portion having an opening at the spherical surface portion of the hermetically sealed case, and an airtight fit in the opening of the mounting portion. part comprising a sealing terminal and is electrically connected to the spherical portion of the sealed case, the spherical radius of the sealing case
A hermetic compressor characterized by being set to 50 to 100% of the inner diameter of the cylinder . 2. The hermetically sealed terminal, wherein a cap portion forming the hermetically sealed terminal is formed in a spherical shape.
The hermetic compressor described. 3. The hermetic compressor according to claim 2 , wherein the cap portion has a spherical radius equal to or smaller than the spherical radius of the spherical portion.