EP3315774A1

EP3315774A1 - Hermetic electric compressor

Info

Publication number: EP3315774A1
Application number: EP16846209.1A
Authority: EP
Inventors: Ikuo Esaki; Shigeki Miura; Hajime Sato; Makoto Ogawa; Masanari Uno; Hirofumi SHIMAYA
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2015-09-17
Filing date: 2016-08-24
Publication date: 2018-05-02
Also published as: JP6151324B2; CN107709775A; JP2017057807A; WO2017047338A1; EP3315774A4

Abstract

The present invention reduces compressive stress and magnetic loss during shrink-fitting or press-fitting of a stator, and improves motor efficiency, without the need to change the shape of a stator core of the stator and without significantly enlarging a sealed housing. A hermetic electric compressor (1) in which an electric motor (5) and a compression mechanism (6) are fixedly installed within a cylindrical sealed housing (2) and the compression mechanism (6) can be driven by the electric motor (5) via a drive shaft (13), wherein the electric motor (5) is fixedly installed by shrink-fitting or press-fitting only a partial range (h1 to h5) of the stator (11) in its thickness direction to an inner peripheral surface of the sealed housing (2), and the remaining portion of the stator is in non-contact with the inner peripheral surface of the housing by increasing the inner diameter of the sealed housing (2).

Description

Technical Field

The invention relates to the hermetic electric compressor in which a compression mechanism and an electric motor that drives the compression mechanism are built within a cylindrical sealed housing.

Background Art

As refrigerant compressors to be applied to freezing and air-conditioning apparatuses or various heat pumps, hermetic electric compressors, such as rotary type compressors or scroll type compressors, in which a compression mechanism and an electric motor driving this compression mechanism is built within a sealed housing having a cylindrical shape, are used. In such hermetic electric compressors, a stator of the electric motor is configured such that a plurality of annularly blanked electromagnetic steel sheets are stacked to form a stator core having a predetermined thickness, and coil winding is wound around the stator core. When this electric motor is built within the sealed housing, the stator is fixedly installed by being shrink-fitted or press-fitted to an inner peripheral surface of the sealed housing.
However, if the stator of the electric motor is fixedly installed by being shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing as above, the compressive stress corresponding to a clamping force during the shrink-fitting or press-fitting remains in the stator core of the stator. It is known that, if the compressive stress remains in the stator core in this way, motor efficiency decreases because the permeability of the magnetic steel sheets constituting the stator core decreases and iron loss (magnetic loss) increases.
Thus, techniques as shown in Patent Document 1 to 4 and the like are suggested in order to reduce the compressive stress applied to the stator and the magnetic loss during the shrink-fitting or press-fitting. Patent Document 1 shows that a pair of upper and lower ring-shaped intermediate members are anchored to upper and lower end parts of an outer peripheral edge of the stator, and the ring-shaped intermediate member are shrink-fitted to an inner peripheral surface of a sealed housing. Patent Document 2 shows that a plurality of swelling groove parts that partially expand in inner diameter and extend in a cylinder axis direction are provided in a circumferential direction in a site on a sealed housing side to which the stator is shrink-fitted, and thus portions in non-contact with an outer periphery of the stator are formed.
Additionally, Patent Documents 3 and 4 show that only a partial range of a stator in its thickness direction is shrink-fitted or press-fitted and is fixedly installed by forming a site that changes the outer diameter of a stator core and is shrink-fitted to an inner peripheral surface of a housing, and a site in non-contact with the inner peripheral surface of the housing, at an outer peripheral site of the stator to be shrink-fitted to the inner peripheral surface of the sealed housing.

Citation List

Patent Literature

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2009-299524
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2010-174772
[Patent Document 3] Japanese Unexamined Patent Application Publication No. 2011-152041
[Patent Document 4] Japanese Unexamined Patent Application Publication No. 2014-117090

Summary of Invention

Technical Problem

However, in the techniques shown in the above Patent Documents, the compressive stress or the iron loss (magnetic loss) that remains in the stator during the shrink-fitting or press-fitting can be reduced, and the motor efficiency can be improved. On the other hand, in the technique shown Patent Document 1, the ring-shaped intermediate members have to be interposed between the stator core and the sealed housing, and it is necessary to enlarge the sealed housing or reduce the diameter of the stator core by that amount. Therefore, there are problems that not only the motor performance is affected but also the structure becomes complicated and cost increases due to an increase in an assembling man-hours or the number of parts.
In the technique shown in Patent Document 2, in the plurality of swelling groove parts provided in the circumferential direction, the sealed housing and the stator core are in non-contact with each other and are not subjected to press-fitting or shrink-fitting. However, a clamping force is applied to the stator core from substantially the entire circumferential direction in the full range in the thickness direction. Therefore, the effect of reducing the compressive stress or the magnetic loss is small, and the effect of improving the motor efficiency is limited. Additionally, in the techniques shown in Patent Documents 3 and 4, the shape of the stator core have to be changed. Therefore, a problem such as inevitably affecting the magnetic performance and the motor performance of the stator.
The invention has been made in view of the above circumstances, and an object thereof is to provide a hermetic electric compressor that can reduce compressive stress and magnetic loss during shrink-fitting or press-fitting of a stator, and can improve motor efficiency, without the need to change the shape of a stator core of the stator and without significantly enlarging a sealed housing.

Solution to Problem

In order to solve the above-described problems, the hermetic electric compressor of the invention adopts the following means.
That is, a hermetic electric compressor related an aspect of the invention includes a cylindrical sealed housing; a compression mechanism fixedly installed within the sealed housing; and an electric motor fixedly installed within the sealed housing by shrink-fitting or press-fitting to drive the compression mechanism via a drive shaft. The electric motor is fixedly installed by shrink-fitting or press-fitting only a partial range h of the stator in its thickness direction on an inner peripheral surface of the sealed housing, and a remaining portion of the stator is in non-contact with the inner peripheral surface of the housing by increasing an inner diameter of the sealed housing.
According to one aspect of the invention, only the partial range h of the stator in its thickness direction is shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing, and the remaining portion is in non-contact with the inner peripheral surface of the housing by increasing the diameter of the inner peripheral surface of the sealed housing. Therefore, the compressive stress and the magnetic loss caused by the shrink-fitting or press-fitting of the stator can be minimized by shrink-fitting or press-fitting only the partial range h of the thickness-direction dimension of the stator to the inner peripheral surface of the sealed housing and installing the remaining portion on the inner peripheral surface of the housing in a non-contact manner without shrink-fitting or press-fitting the remaining portion in order to obtain a minimum holding force required to fixedly install the electric motor within the sealed housing. Therefore, it is possible to improve the motor efficiency and improve the motor performance without affecting the magnetic performance of the stator in any way. Additionally, the diameter of only the portion of the sealed housing corresponding to the installation site of the stator may be increased, and the enlargement of the sealed housing and thus the hermetic electric compressor can be avoided.
Moreover, in the hermetic electric compressor of one aspect of the invention based on the above hermetic electric compressor, the thickness-direction range h of the stator to be shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing is set to a range of 0.05 L to 0.75 L with respect to a total thickness-direction dimension L.
According to one aspect of the invention, the shrink-fitted or press-fitted thickness-direction range h of the stator to be shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing is set to the range of 0.05 to 0.75L with respect to the total thickness-direction dimension L. Therefore, the compressive stress and the magnetic loss caused by the shrink-fitting or press-fitting can be made as small as possible while securing the holding force required to fixedly install the electric motor. That is, the necessary minimum stator holding force can be secured by setting the range h where the stator is shrink-fitted or press-fitted to 0.05 L or more of the total thickness-direction dimension L, and the compressive stress and the magnetic loss of the stator caused by the shrink-fitting or press-fitting can be made sufficiently small by setting the shrink-fitted or press-fitted range h to 0.75 L or less of the total thickness-direction dimension L. Therefore, there is no need to change the shape of the stator, and it is possible to improve the motor efficiency and improve the motor performance while without affecting the magnetic performance.
Moreover, in the hermetic electric compressor of one aspect of the invention based on any of the above hermetic electric compressors, the thickness-direction range h of the stator to be shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing is any one of one end site, the other end site, both end sites, or a central site of the stator in its thickness direction.
According to one aspect of the invention, the thickness-direction range h of the stator to be shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing is set to any of the one end site, the other end site, both end sites, or the central site of the stator in its thickness direction. Therefore, the thickness-direction range h of the stator to shrink-fitted or press-fitted may be set to an optimal position in which diameter increase machining of the sealed housing or the contact distance when the stator is inserted into a shrink-fitting position or press-fitting position of the sealed housing is taken into consideration, in any position the one end site, the other end site, both end sites, or the central site of the stator in it the thickness direction. Thus, the thickness-direction range h when the stator is shrink-fitted or press-fitted can be freely set, and free selection can be secured when determining the external shape of the sealed housing or the fixing structure of the stator. Additionally, by setting the shrink-fitting or press-fitting range h to the one end site, the other end site, both end sites, or the central site of the stator in its thickness direction, the mutual contact distance when the stator is inserted into the shrink-fitting or press-fitting position of the sealed housing can be shortened. Therefore, particularly the press-fitting can be further facilitated.
Moreover, in the hermetic electric compressor of the aspect of the invention based on any of the above hermetic electric compressors, in the inner peripheral surface of the sealed housing, a portion corresponding to a site to which at least the partial range h of the stator is shrink-fitted or press-fitted is made to have an inner diameter D having a shrink-fitting allowance or a press-fitting allowance, and the other portions are made to have the same inner diameter D as the shrink-fitted or press-fitted portion or have an inner diameter D1 capable of inserting the stator or an inner diameter D2 larger than the inner diameter D1, in accordance with the positions of the portions.
According to one aspect of the invention, at least the portion corresponding to the site in the inner peripheral surface of the sealed housing to which the partial range h of the stator is shrink-fitted or press-fitted is made to have the inner diameter D having the shrink-fitting allowance or the press-fitting allowance, and the other portions are made to have the same inner diameter D as the shrink-fitted or press-fitted portion or have the inner diameter D1 capable of inserting the stator or the inner diameter D2 larger than the inner diameter D1, in accordance with the positions of the portions. Therefore, the partial range h of the stator in its thickness direction can be shrink-fitted or press-fitted to and fixedly installed on the inner peripheral surface of the sealed housing made to have the inner diameter D having the shrink-fitting allowance or the press-fitting allowance. Also, by making the other portions of the sealed housing have the same inner diameter D as the shrink-fitted or press-fitted portion, the inner diameter D1 capable of inserting the stator or the inner diameter D2 larger than the inner diameter D1, in accordance with to the position of the stator, the stator can be smoothly inserted into the sealed housing, and can be shrink-fitted or press-fitted to a predetermined portion. Therefore, by appropriately and partially increasing the diameter of only a required portion of the sealed housing, the stator can be fixedly installed without significantly enlarging the sealed housing, and the enlargement of the sealed housing and thus a hermetic electric compressor can be avoided.

Advantageous Effects of Invention

According to the invention, the compressive stress and the magnetic loss caused by the shrink-fitting or press-fitting of the stator can be minimized by shrink-fitting or press-fitting only the partial range h of the thickness-direction dimension of the stator to the inner peripheral surface of the sealed housing and installing the remaining portion on the inner peripheral surface of the housing in a non-contact manner without shrink-fitting or press-fitting the remaining portion so that the minimum holding force required to fixedly install the electric motor to the sealed housing can be secured. Therefore, it is possible to improve the motor efficiency and improve the motor performance without affecting the magnetic performance of the stator in any way. Additionally, the diameter of only the portion of the sealed housing corresponding to the installation site of the stator may be increased, and the enlargement of the sealed housing and thus the hermetic electric compressor can be avoided.

Brief Description of Drawings

Fig. 1 is a longitudinal sectional view of a hermetic electric compressor related to a first embodiment of the invention.
Fig. 2 is a view equivalent to section a-a in Fig. 1.
Fig. 3 is a longitudinal sectional view of a hermetic electric compressor of another embodiment (1).
Fig. 4 is a longitudinal sectional view of a hermetic electric compressor of still another embodiment (2) .
Fig. 5 is a longitudinal sectional view of a hermetic electric compressor of a still further embodiment (3) .
Fig. 6 is a graph illustrating a relationship among magnetic loss caused by the shrink-fitting of a stator, a stator holding force, and a shrink-fitting range rate in the above hermetic electric compressor.

Description of Embodiments

Hereinafter, embodiments related to the invention will be described with reference to the drawings.

[First Embodiment]

Hereinafter, a first embodiment of the invention will be described with reference to Figs. 1, 2, and 6.
Fig. 1 is a longitudinal sectional view of a hermetic electric compressor related to a first embodiment of the invention, Fig. 2 is a view equivalent to section a-a in Fig. 1, and Fig. 6 is a graph illustrating a relationship among magnetic loss caused by the shrink-fitting of a stator, a stator holding force, and a shrink-fitting range rate in the above hermetic electric compressor.
Here, although a rotary hermetic electric compressor is exemplified as the hermetic electric compressor 1, it is needless to say that the invention is not limited to this and the same applies to other types of hermetic electric compressors, such as a scroll type.
The hermetic electric compressor 1 includes a cylindrical sealed housing 2 in which an upper end part and a lower end part are sealed by covers 3 and 4, and has a configuration in which an electric motor 5 is fixedly installed at an inner upper part thereof and a compression mechanism (rotary compressor mechanism) 6 to be driven by the electric motor 5 is fixedly installed at a lower part thereof. A plurality of mounting legs 7 are provided at a lower outer periphery of the sealed housing 2, and an upper part of the sealed housing 2 is provided with a sealed terminal 8 that passes through the cover 3 and supplies electric power to the electric motor 5.
Moreover, a suction pipe 9 that allows a low-pressure refrigerant gas, which returns from a refrigeration cycle side, to be suctioned into the compression mechanism 6 via an accumulator (not illustrated) therethrough is connected to a lower part of the sealed housing 2. A discharge pipe 10 is provided at the upper part of the sealed housing 2 so as to pass through the cover 3, and a high-temperature high-pressure refrigerant gas compressed by the compression mechanism 6 is allowed to be discharged to the outside (refrigeration cycle).
The electric motor 5 is constituted of a stator 11 and a rotor 12, and the stator 11 is fixedly installed by being shrink-fitted or press-fitted to an inner peripheral surface of the sealed housing 2. A drive shaft 13 is integrally combined with the rotor 12, and rotational power is allowed to be transmitted to the compression mechanism 6 via the drive shaft 13. An eccentric part 14 is provided at a lower site of the drive shaft 13 in correspondence with the installation position of a rolling piston 19 of the compression mechanism 6.
The compression mechanism (rotary compressor mechanism) 6 is configured to include a cylinder body 15 that forms a cylinder chamber 16 and is fixedly installed within the sealed housing 2 at a position corresponding to the eccentric part 14 of the drive shaft 13, an upper bearing 17 and a lower bearing 18 that are fixedly installed on an upper surface and a lower surface of the cylinder body 15, partition the cylinder chamber 16, and rotatably support the drive shaft 13, a rolling piston that is turnably fitted to the eccentric part 14 of the drive shaft 13 and turns within the cylinder chamber 16, and a vane (not illustrated) that is slidably fitted to a groove (not illustrated) provided in the cylinder body 15, partitions the inside of the cylinder chamber 16 into a discharge side and a suction side. The compression mechanism 6 having this configuration is known well.
A low-pressure refrigerant gas is suctioned into the cylinder chamber 16 of the compression mechanism 6 through a suction port 20 from the suction pipe 9. After this refrigerant gas is compressed by the turning of the rolling piston 19, the refrigerant gas is discharged into a discharge chamber 21 through a discharge port (not illustrated), and an ejection valve, and is discharged into the sealed housing 2 from the discharge chamber. The high-temperature high-pressure refrigerant gas discharged into the sealed housing 2 is guided to an upper space within the sealed housing 2 through a refrigerant passage provided between the inner peripheral surface of the sealed housing 2 and an outer peripheral surface of the stator 11 of the electric motor 5, and is discharged to the outside (refrigeration cycle side) through the discharge pipe 10.
A lower end part of the drive shaft 13 is provided with an oil pump 22, and lubricating oil with filled into a bottom part within the sealed housing 2 via an oil supply hole 23 or the like provided in the drive shaft 13 is allowed to be supplied to lubrication sites, such as a bearing portion and a sliding portion of the compression mechanism 6.
In the above hermetic electric compressor 1, the stator 11 of the electric motor 5 is shrink-fitted or press-fitted as follows in order to reduce compressive stress or magnetic loss (iron loss) when being shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing 2 and improved motor efficiency.
The stator 11 of the electric motor 5 is obtained by blanking an electromagnetic steel sheet in an annular shape, stacking a plurality of the steel sheets to form a stator core 11A having a predetermined thickness L, and winding coil winding 11B around a teeth part. Since the stator core 11A herein is shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing 2, particularly, the outer shape thereof is not a deformed shape but has a cylindrical shape.
Meanwhile, regarding the inner peripheral surface of the sealed housing 2 to which the stator core 11A of the stator 11 is shrink-fitted or press-fitted, when only a partial range h (h1) of the total thickness-direction dimension L of the stator 11 is defined as a range where the stator is shrink-fitted or press-fitted to the inner peripheral surface of the housing, the inner diameter of a press-fitted portion 2A corresponding to the partial range h (h1) of the stator 11 is defined as D, and the remaining portion has the same inner diameter D as the shrink-fitted or press-fitted portion 2A, an inner diameter D1 (D1 > D) or an inner diameter D2 (D2 > D1) larger than the inner diameter D1 capable of inserting the stator 11, in accordance with the position of the remaining portion.
That is, in the present embodiment, the inner diameter of the sealed housing 2 is set to the inner diameter D in which the inner diameter of the shrink-fitted or press-fitted portion 2A of the stator 11 has a shrink-fitting allowance or a press-fitting allowance, the inner diameter of a lower portion 2B below the shrink-fitted or press-fitted portion 2A is set to the same inner diameter D because the inner diameter of the lower portion 2B may be the same inner diameter D as the shrink-fitted or press-fitted portion 2A, and the inner diameter of an upper portion 2C above the shrink-fitted or press-fitted portion 2A is set to the inner diameter D1 (D1 > D) or the inner diameter D2 (D2> D1) larger than the inner diameter D1 so that the stator 11 can be inserted in the state before welding the cover 3.
Accordingly, in the upper portion 2C above the shrink-fitted or press-fitted portion 2A on the sealed housing 2 side corresponding to the range h (h1) where the stator 11 is shrink-fitted or press-fitted, a gap S is set between the inner peripheral surface of the sealed housing 2 and the outer peripheral surface of the stator 11 such that these inner and outer surfaces are in non-contact with each other. It is desirable that the gap S has a size such that, even if the vibration caused by an electromagnetic excitation force is generated on the stator 11 side of the electric motor 5, the vibration is not prevented from propagating to the sealed housing 2 side due to mutual contact.
Moreover, the range h (h1) where the stator 11 is shrink-fitted or press-fitted to the sealed housing 2 have to be a range where the compressive stress and the magnetic loss caused by the shrink-fitting or the press-fitting can be made as small as possible while securing the holding force required to fixedly install the electric motor 5. Fig. 6 is a graph illustrating a relationship among the magnetic loss caused by the shrink-fitting of the stator 11, the stator holding force, and the shrink-fitting range rate (h(h1)/L) in the above hermetic electric compressor 1.
As illustrated in this graph, in order to secure a necessary minimum stator holding force, it is necessary to set the thickness-direction range h(h1) of the stator 11 to be shrink-fitted or press-fitted to 0.05 L or more with respect to the total thickness-direction dimension L of the stator 11. Additionally, in order to make the compressive stress and the magnetic loss caused by the shrink-fitting or press-fitting of the stator 11 sufficiently small, it is necessary to set the thickness-direction range h(h1) of the stator 11 to be shrink-fitted or press-fitted to 0.75 L or less with respect to the total thickness-direction dimension L of the stator 11. A more preferable range h (h1) is 1/3L < h(h1) < 1/2L.
According to the present embodiment, the following effects are exhibited by virtue of the above-described configuration.
In the above hermetic electric compressor 1, if the compression mechanism 6 is driven via the drive shaft 13 by electric power being supplied by the electric motor 5 and the rotor 12 being rotated, a low-pressure refrigerant gas is suctioned into the cylinder chamber 16 of the compression mechanism 6 via the suction pipe 9 and compressed by the turning of the rolling piston 19, and then, is discharged into the discharge chamber 21 via the discharge port and a ejection valve (not illustrated).
This high-temperature high-pressure compressed gas is discharged into the sealed housing 2 from the discharge chamber 21, and then, is guided to the upper space within the sealed housing 2 through the refrigerant passage formed between the inner peripheral surface of the sealed housing 2 and the outer peripheral surface of the stator 11, and is discharged through the discharge pipe 10 on the refrigeration cycle side from the upper surface. During this compression operation, the electric motor 5 is rotated at a controlled rotation speed, and continues driving the compression mechanism 6.
When the electric motor 5 is assembled, it is necessary to insert the stator 11 into the sealed housing 2 in the state before the cover 3 is welded, shrink-fit or press-fit the shrink-fitted or press-fitted range h (h1), which is a partial range of the thickness-direction dimension L of the stator 11, to the shrink-fitted or press-fitted portion 2A of the sealed housing 2, and then the electric motor 5 is assembled into the sealed housing 2 by assembling the rotor 12 into which the drive shaft 13 is integrated.
In this case, in the electric motor 5, the partial range h of the stator 11 (h1) in its thickness direction is shrink-fitted or press-fitted to the inner peripheral surface of the shrink-fitted or press-fitted portion 2A of the sealed housing 2, and the remaining portion is in non-contact with the inner peripheral surface of the housing by increasing the diameter (an increase in diameter to D1 or D2) of the inner diameter of the sealed housing 2. That is, when the total thickness-direction dimension of the stator 11 is defined as L, only the shrink-fitted or press-fitted range h (h1) that is a portion of the stator 11 is set to the shrink-fitted or press-fitted range, and "0.05L< h(h1) < 0.75L", preferably, "1/3L < h(h1) < 1/2L" is set to the shrink-fitted or press-fitted range.
In this way, the compressive stress and the magnetic loss (iron loss) caused by the shrink-fitting or press-fitting of the stator 11 can be minimized by shrink-fitting or press-fitting the partial range h (h1) of the thickness-direction dimension of the stator 11 to the inner peripheral surface of the sealed housing 2 and installing the remaining portion on the inner peripheral surface of the housing in a non-contact manner without shrink-fitting or press-fitting the remaining portion so that the minimum holding force required to fixedly install the electric motor 5 into the sealed housing 2 can be secured.
For this reason, it is possible to improve the motor efficiency and improve the motor performance without affecting the magnetic performance of the stator 11 in any way. Additionally, the diameter of only a portion of the sealed housing 2 corresponding to the installation site of the stator 11 may be increased, and the enlargement of the sealed housing 2 and thus the hermetic electric compressor 1 can be avoided. Moreover, since the remaining portion of the stator 11 that is not shrink-fitted or press-fitted is in non-contact with the inner peripheral surface of the sealed housings 2 due to the gap S, generation of noise by the magnetic excitation force on the stator 11 side propagating to the sealed housing 2 can also be suppressed.
Moreover, the shrink-fitted or press-fitted range h (h1) of the stator 11 is set to the range of 0.05 L< h(h1) < 0.75L, preferably, the range of 1/3L < h(h1) < 1/2 with respect to the total thickness-direction dimension L of the stator 11, the compressive stress and the magnetic loss of the stator 11 caused by the shrink-fitting or press-fitting can be made as small as possible while securing the holding force required to fixedly install the electric motor 5. That is, the necessary minimum stator holding force can be secured by setting the range h (h1) where the stator 11 is shrink-fitted or press-fitted to 0.05L or more of the total thickness-direction dimension L, and the compressive stress and the magnetic loss of the stator 11 caused by the shrink-fitting or press-fitting can be made sufficiently small by setting the shrink-fitted or press-fitted range h(h1) to 0.75L or less of the total thickness-direction dimension L.
For this reason, there is no need to change the shape of the stator 11, and it is possible to improve the motor efficiency and improve the motor performance while without affecting the magnetic performance.
Additionally, since the partial range h(h1) to be shrink-fitted or press-fitted is set to only one end site of the stator 11 in its thickness direction, a mutual contact distance when the stator 11 is inserted into a shrink-fitting or press-fitting position of the sealed housing 2 can be shortened, and thereby, particularly the fixedly installation caused by the press-fitting of the stator 11 can be further facilitated.
Moreover, the press-fitted portion 2A corresponding to the site of the inner peripheral surface of the sealed housing 2 where the partial range h(h1) of the stator 11 is shrink-fitted or press-fitted is made to have the inner diameter D having the shrink-fitting allowance or the press-fitting allowance. In the other portions 2B and 2C, the lower portion 2B below the shrink-fitted or press-fitted portion 2A is made to have the same inner diameter D as the shrink-fitted or press-fitted portion 2A, and the upper portion 2C is made to have the inner diameter D1 capable of inserting the stator 11 or the inner diameter D2 larger than the inner diameter D1, in accordance with the positions of the portions.
Accordingly, the partial range h(h1) of the stator 11 in its thickness direction can be shrink-fitted or press-fitted to and fixedly installed on the inner peripheral surface of the sealed housing 2 made to have the inner diameter D having the shrink-fitting allowance or the press-fitting allowance. Also, by making the other portions 2B and 2C of the sealed housing 2 have the same inner diameter D as the shrink-fitted or press-fitted portion 2A, the inner diameter D1 or the inner diameter D2 larger than the inner diameter D1 capable of inserting the stator 11, in accordance with to the position of the stator 11, the stator 11 can be smoothly inserted from an upper end part of the sealed housing 2 in a state where the cover 3 is removed, and can be shrink-fitted or press-fitted to the shrink-fitted or press-fitted portion 2A.
For this reason, by appropriately and partially increasing the diameter of only a required portion of the sealed housing 2, for example, the upper portion 2C above the shrink-fitted or press-fitted portion 2A of the sealed housing 2, the stator 11 can be fixedly installed without significantly enlarging the sealed housing 2, and the enlargement of the sealed housing 2 and thus the hermetic electric compressor 1 can be avoided.

[Other Embodiments]

Next, other embodiments of the invention will be described with reference to Figs. 3 to 5.
Although an example in which the stator 11 can be inserted and shrink-fitted or press-fitted from the upper end part of the sealed housing 2 by setting the one end site, which is an upper end side with respect the total thickness-direction dimension L of the stator 11, to the partial range h(h1) to be shrink-fitted or press-fitted and by setting the inner diameter of the upper portion 2C above the shrink-fitted or press-fitted portion 2A of the sealed housing 2 to the inner diameter D1 or D2 larger than the inner diameter D of the press-fitted portion 2A has been described in the above-described first embodiment, the following embodiments (1), (2), and (3) may be adopted.

(1) As illustrated in Fig. 3, the other end site, which is a lower end side with respect to the total thickness-direction dimension L of the stator 11, may be set to a partial range h(h2) to be shrink-fitted or press-fitted, the inner diameter of a shrink-fitted or press-fitted portion 2D of the sealed housing 2 may be set to the inner diameter D having the shrink-fitting allowance or the press-fitting allowance, and the inner diameter of an upper portion 2E above the shrink-fitted or press-fitted portion 2D may be set to the same inner diameter D as the shrink-fitted or press-fitted portion 2D. Therefore, the same inner diameter D, and the inner diameter of a lower portion 2F below the shrink-fitted or press-fitted portion 2D may be set to the inner diameter D1 (D1 > D) or the inner diameter D2 (D2 > D1) larger than the inner diameter D1 so that the stator 11 can be easily inserted before the cover 4 is welded and the electric motor 5 and the compression mechanism 6 can be assembled.
Even if this configuration is adopted, the same effects as the above-described first embodiment can be obtained. In this case, the diameter of only a lower half part of the sealed housing 2 may be increased such that the gap S between the lower half part and an outer periphery of the stator 11, and non-contact therebetween is brought about, and the stator 11 may be inserted from and shrink-fitted or press-fitted to the lower end part side of the sealed housing 2.
(2) As illustrated in Fig. 4, upper and lower end sites with respect to the total thickness-direction dimension L of the stator 11 may be set to partial ranges h3, h4 (h3 + h4 = h) to be shrink-fitted or press-fitted, the inner diameter of shrink-fitted or press-fitted portions 2G and 2H of the sealed housing 2 may be set to the inner diameter D having the shrink-fitting allowance or the press-fitting allowance, the inner diameter of any one of an upper portion 2I and a lower portion 2J above and below the shrink-fitted or press-fitted portions 2G and 2H may be set to the same inner diameter D, inner diameter D1 (D1 > D) larger than the inner diameter D, or the inner diameter D2 (D2 > D1) larger than D1 because this inner diameter of the upper or lower portion may be the same inner diameter D as the shrink-fitted or press-fitted portions 2G and 2H, and the inner diameter of the other portion may be set to the inner diameter D1 (D1 > D) capable of easily inserting the stator 11 inserted before the covers 3 and 4 are welded or the inner diameter D2 (D2 > D1) larger than the inner diameter D1. Additionally, the gap S is set between an intermediate portion 2K between the press-fitted portions 2G and 2H and the outer periphery of the stator 11 by setting the inner diameter of the intermediate portion 2K to the inner diameter D1 (D1 > D) or the inner diameter D2 (D2 > D1) larger than the inner diameter D1.
Even if such a configuration is adopted, the same effects as the above first embodiment can be obtained. In this case, a total holding force caused by the partial ranges h3 and h4 to be shrink-fitted or press-fitted, which are separately set to a plurality of portions, in the total thickness-direction dimension L of the stator 11 may be set so as to secure a minimum holding force required to fixedly install the electric motor 5 with respect to the sealed housing 2.
(3) As illustrated in Fig. 5, a central site excluding both end parts with respect to the total thickness-direction dimension L of the stator 11, may be set to a partial range h (h5) to be shrink-fitted or press-fitted, the inner diameter of a shrink-fitted or press-fitted portion 2L of the sealed housing 2 may be set to the inner diameter D having the shrink-fitting allowance or the press-fitting allowance, and the inner diameter of an upper portion 2M and a lower portion 2N above and below the shrink-fitted or press-fitted portion 2L may be set to the inner diameter D1 (D1 > D) or the inner diameter D2 (D2 > D1) larger than the inner diameter D1, thereby, setting the gap S between the upper and lower portions and the outer periphery of the stator 11, so that the stator 11 can be easily inserted.

Even if the invention is configured as above, the same effects as the above first embodiment can be obtained. However, in this case, the inner diameter of an upper portion 2M and a lower portion 2N of the sealed housing 2 corresponding to a remaining portion excluding the partial range h (h5) of the stator 11 may be set to D2, and the inner diameter of the other portions may be set to D1.
Moreover, as shown in the above-described first embodiment and other embodiments (1), (2), and (3), the thickness-direction range h (h1 to h5) of the stator 11 to be shrink-fitted or press-fitted may be set to the one end site, the other end site, both end sites, or the central site of the stator 11 in its thickness direction by setting the thickness-direction range h (h1 to h5) of the stator 11, which is shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing 2, to the one end site, the other end site, both end sites, or the central site of the stator 11 in its thickness direction, and it is possible to set an optimal position in which diameter increase machining of the sealed housing 2 or the contact distance when the stator 11 is inserted into a shrink-fitting position or press-fitting position of the sealed housing 2 is taken into consideration.
As a result, the thickness-direction range h (h1 to h5) where the stator 11 is shrink-fitted or press-fitted can be freely set, and free selection can be secured when determining the external shape of the sealed housing 2 or the fixing structure of the stator 11. Additionally, by setting the range h (h1 to h5) to be shrink-fitted or press-fitted to the one end site, the other end site, both end sites, or the central site of the stator 11 in its thickness direction, the mutual contact distance when the stator 11 is inserted into the shrink-fitting or press-fitting position of the sealed housing 2 can be shortened, and particularly the press-fitting can be further facilitated.
In addition, the invention is not limited to the inventions related to the above embodiments, and can be appropriately modified without departing from the scope of the invention. For example, in the above embodiments, an example in which the invention is applied to a single-cylinder rotary hermetic electric compressor 1 has been described as an example of the hermetic electric compressor 1. However, the invention is not limited to this. It goes without saying that the invention can be widely applied to multi-cylinder rotary hermetic electric compressors, or various types of hermetic electric compressors in which the electric motor 5 is fixedly installed in the sealed housing 2, for example, scroll type hermetic electric compressors, or multistage compressors in which a plurality of compression mechanisms to be driven by the electric motor 5 are built within the sealed housing 2.

Reference Signs List

1: HERMETIC ELECTRIC COMPRESSOR
2: SEALED HOUSING
2A, 2D, 2G, 2H, 2L: PORTION TO WHICH STATOR IS SHRINK-FITTED OR PRESS-FITTED
2B, 2C, 2E, 2F, 2I, 2J, 2K, 2M, 2N: OTHER PORTIONS
5: ELECTRIC MOTOR
6: COMPRESSION MECHANISM
11: STATOR
13: DRIVE SHAFT
h (h1, h2, h3, h4, h5): THICKNESS-DIRECTION RANGE WHERE STATOR IS SHRINK-FITTED OR PRESS-FITTED
L: TOTAL THICKNESS-DIRECTION DIMENSION OF STATOR

Claims

A hermetic electric compressor comprising:
a cylindrical sealed housing;

a compression mechanism fixedly installed within the sealed housing; and

an electric motor fixedly installed within the sealed housing by shrink-fitting or press-fitting to drive the compression mechanism via a drive shaft,

wherein the electric motor is fixedly installed by shrink-fitting or press-fitting only a partial range h of the stator in its thickness direction on an inner peripheral surface of the sealed housing, and a remaining portion of the stator is in non-contact with the inner peripheral surface of the housing by increasing an inner diameter of the sealed housing.
The hermetic electric compressor according to Claim 1,
wherein the thickness-direction range h of the stator to be shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing is set to a range of 0.05 L to 0.75 L with respect to a total thickness-direction dimension L.
The hermetic electric compressor according to Claim 1 or 2,
wherein the thickness-direction range h of the stator to be shrink-fitted or press-fitted to the inner peripheral surface of the sealed housing is any one of one end site, the other end site, both end sites, or a central site of the stator in its thickness direction.
The hermetic electric compressor according to any one of Claims 1 to 3,
wherein in the inner peripheral surface of the sealed housing, a portion corresponding to a site to which at least the partial range h of the stator is shrink-fitted or press-fitted is made to have an inner diameter D having a shrink-fitting allowance or a press-fitting allowance, and the other portions are made to have the same inner diameter D as the shrink-fitted or press-fitted portion or have an inner diameter D1 capable of inserting the stator or an inner diameter D2 larger than the inner diameter D1, in accordance with the positions of the portions.