JPH073260U - Reinforced structure of can of canned motor - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention can obtain a sufficient buckling prevention force against negative pressure or external pressure acting in the radial direction of the can, and also has an effective can cooling structure. A canned motor reinforcement structure is obtained. According to the present invention, in a canned motor, in order to prevent buckling due to negative pressure or external pressure that acts in the radial direction of the can, a can formed of an annular groove or an annular slit opening on the inner peripheral surface side of the stator core that contacts the can. A structure is provided in which one or a plurality of receiving portions are provided, and an annular bulging portion which can be fitted tightly with the can receiving portion is provided on the can side, whereby the buckling strength of the can is reinforced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a can reinforcing structure for a can of a canned motor. In a compressor for refrigeration, a compressor for a vacuum pump, etc., when the external pressure applied to the can becomes larger than the internal pressure, the can is reinforced against buckling. Canned motor.

[0002]

[Prior art]

 Conventionally, a canned motor has a sealed structure in which the motor side shuts off the fluid leakage from the drive bearing of the driven fluid machine on the motor side and the atmosphere side. Since the insulation resistance against the fluid cannot be obtained, the stator coil is separated via a can. This type of canned motor allows high-density alternating magnetic flux from the stator core and stator coil to pass through to the rotor, but the air gap can be set to a narrow value as long as it does not hinder the rotation of the rotor. If necessary, the thickness of the cylindrical can inserted into the gap must be thin and pressure resistant. This type of canned motor is generally integrated with a driven fluid machine as a load and has a completely sealed structure. For example, the inside of the can of a can motor for a refrigeration compressor is connected to the low-pressure part on the compressor side, and its internal pressure is wide ranging from negative pressure to positive pressure in response to cooling load. Although the pressure changes, it is easy to design as a pressure resistant container due to its structure against positive pressure, but it is possible to cancel due to negative pressure generated during operation and can cooling. In a structure in which cooling oil is circulated around the outer circumference, the external pressure of the can becomes larger than the internal pressure, and the can with a thin structure is pressed, which may cause buckling. Also, with a large capacity canned motor, the diameter of the can becomes large, and to increase the thickness of the can accordingly, it is necessary to transmit high-density alternating magnetic flux from the stator ring to the rotor. Due to the characteristics of the can, its realization is difficult. Therefore, the larger the capacity of the canned motor, the more easily the deformation and buckling of the can due to the external pressure occur. In order to solve such a drawback, the present inventor previously disclosed, in Japanese Utility Model Laid-Open No. 64-34856, using a stator wheel groove extending axially on the inner diameter side of a fixed iron core to open the wheel groove. A can structure has been proposed in which the can is bulged toward the outer peripheral side along the mouth portion, and a large number of band-shaped ribs are formed in the circumferential direction along the axial direction of the can.

[0003]

[Problems to be solved by the device]

 However, since the negative pressure of the cooling load acts on the axial center of the can in the direction of reducing the diameter, the rib-shaped protrusion in the can longitudinal direction as described above cannot obtain sufficient buckling prevention force. Since the canned motor has a structure in which high-density alternating magnetic flux from the stator coil is transmitted to the rotor through the can, the larger the capacity of the canned motor, the more heat the can generates. Including the above-mentioned prior art, since the inner circumference of the stator core is tightly fitted to the back side of the can, it is difficult to effectively take the cooling structure of the can. The same problem occurs not only in canned motors for driving refrigeration compressors, but also in canned motors for advanced genuine pumps.

In view of the above-mentioned drawbacks of the prior art, the present invention can obtain a sufficient buckling prevention force against a negative pressure or an external pressure acting in the radial direction of the can, and also has an effective can cooling structure. The object is to provide a reinforced structure of a canned motor capable of doing so.

[0005]

[Means for Solving the Problems]

 In the present invention, in order to prevent buckling due to negative pressure or external pressure that acts in the radial direction of the can of a can motor, an annular groove or an annular slit opening is formed on the inner surface of the stator core in contact with the can. The structure is such that one or a plurality of receiving portions are provided and an annular bulging portion which can be fitted tightly with the can receiving portion is provided on the can side, whereby the buckling strength of the can is reinforced. Further, if necessary, the corner portion of the can receiving portion contacting the inner circumference of the stator core is chamfered so that the can can be swollen smoothly and the can can be prevented from being unnecessarily deformed. Thus, the reinforcing effect can be further improved. In order to provide such an annular bulge portion on the can, band-shaped grooves or annular slit openings are provided at necessary intervals on the inner peripheral surface of the stator core, and the corner portions contacting the inner periphery of the stator core are provided. After chamfering, a can is inserted into the inner circumference of the stator core, and a thin roller with a semicircular cross section whose contact surface is angled at the position corresponding to the can receiving part. The can may be bulged by applying pressure to the can, or may be bulged by hydraulic pressure from the inside of the can. In this way, the machining process for the can is usually performed for fitting the can to the inner peripheral surface of the stator so as to be in close contact, and this is not a special work particularly performed for forming the annular groove. Since it is a work that can be regarded as an extension of the conventional work process, it can be performed very easily.

[0006]

[Action]

 Therefore, according to such technical means, the annular bulging portion is not a rib-shaped projection in the longitudinal direction of the can as in the prior art, but an endless end corresponding to the acting force acting in the radial direction toward the axial center of the can. Since it is a ring-shaped protrusion, it is possible to obtain a sufficient buckling prevention force. Also, the larger the capacity of the canned motor, the greater the heat generated by the can, but since the back side of the annular bulging portion has a void as a slit opening, air or oil, etc. can be utilized by utilizing this void. It is easy to flow the cooling fluid, and it is easy to effectively take the cooling structure of the can.

Hereinafter, embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the constituent parts described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified, and are merely explanatory examples. Nothing more than. FIG. 1 is a sectional view of a canned motor according to an embodiment of the present invention. In the drawing, reference numeral 1 is a canned motor, in which a refrigerant compressor 2 is directly connected to a rotary shaft side. 4 is a stator core inserted in the frame 3, 5 is a stator coil wound around the stator core 4, and 6 is supported by bearings 81 arranged at both ends in the axial direction through a rotary shaft 9, A rotor 10 that rotates integrally with the rotary shaft 9 is a thin-walled cylindrical metal can that is fixedly installed on the inner peripheral surface of the stator core 4, and the stator core 3 and both sides thereof are fixed as described later. Are integrally fitted to the inner peripheral surfaces of the reinforcing cylinders 11 and 12. The stator core 4 is divided into left and right parts via a fluid duct 20 having an annular slit opening provided in the center. As shown in FIG. 2C, the fluid duct 20 is provided with a plurality of radially extending duct pieces 21 each having a cross section of “D”, and the duct pieces 21 allow slit gap spacing. While maintaining the above, the divided bodies 4A and 4B of the two stator cores 4 are joined together. Cooling oil supplied by a pump 22 is circulated in the fluid duct 20, and the can 10 is easily expanded without extending the duct piece 21 to the inner peripheral end of the slit opening. Configure to be available. Further, the corner portion of the slit opening, which is in contact with the inner circumference of the stator core 4, is chamfered so that the can 10 can swell smoothly. Then, the cylindrical can 10 is provided with an annular bulge 10a that fits tightly with the inner end of the slit opening 20 by a method described later, and the stator core 4 and the can 10 are integrally connected. That is, as described above, after chamfering the corner portion 20a of the slit opening 20 in contact with the inner periphery of the stator core 4, the can 10 is fitted into the inner periphery of the stator core 4, and is placed at a position corresponding to the can 10 receiving portion. A thin roller (not shown) whose contact surface has a semicircular cross section with an angled surface is used to swell the can 10 by applying pressure outward from the inner peripheral surface of the can 10, or from the inside of the can 10. The can 10 is bulged by hydraulic pressure or the like to be fixed to the can 10 so as to be fitted between the inner circumferences of the iron cores 4, and because the can 10 is thin, one of the cans 10 is fitted in conformity with the inner peripheral end shape of the slit shape. The portion bulges in a ring shape, and the slit opening 20 and the ring-shaped bulged portion 10a of the can 10 are integrally fitted. Reference numeral 6A denotes a rotor space inside the can 10, which is a refrigerant gas in the case of a compressor for refrigeration, and 7 is a space which forms a passage for circulating cooling oil when cooling the outer periphery of the can 10, and is supplied by a pump 22. The cooling oil can be circulated. In the present invention, a plurality of shallow annular grooves 25 are previously provided along the inner circumference of the stator core 4 as shown in FIG. 2 without providing the slit opening 20 as described above. The recess 10 and the can 10 may be integrally fitted to the can 10 through the annular bulging portion 10a by the method, but in such a structure, there is a buckling prevention effect, but cooling is possible. The effect cannot be expected.

[0008]

[Effect of device]

 As described above, according to the present invention, since the annular bulging portion is provided at the required portion of the can and the annular bulging portion is integrally fitted into the ring-shaped recess on the stator core side, the negative pressure in the radial direction of the can is reduced. Alternatively, it is possible to increase the pressure resistance against deformation and buckling due to external pressure. Further, even when the can is expanded in the axial direction by the alternating magnetic flux from the stator during operation, the can can be absorbed and recovered by the ring-shaped expanded portion. Further, since the back surface side of the annular bulging portion has a gap as a slit opening, it is easy to flow a cooling fluid such as air or oil using the gap, and the can cooling structure is effective. It is easy to take. Also, the fluid pressure enhances the strength against external pressure. Cooling can be easily enabled. Further, the present invention is extremely advantageous in practical use because it is not necessary to increase the thickness of the can even in a large capacity canned motor, and cooling from the back side of the can can be performed easily. It has various remarkable effects.

[Brief description of drawings]

1A is a sectional view of a canned motor according to a first embodiment of the present invention, FIG. 1B is a sectional view taken along the line AA, and FIG.
Is an enlarged view of the main part showing the can receiving part and the annular bulging part

FIG. 2 is a sectional view of a main part of a canned motor according to another embodiment of the present invention.

[Explanation of symbols]

 4 stator core 10 can 1 canned motor 25 annular groove 20 annular slit opening 10a annular bulging part

Claims (2)

[Scope of utility model registration request] 1. A canned motor in which a cylindrical thin metal can is fitted on the inner peripheral side of a stator core, and a can receiver having an annular groove or an annular slit opening on the inner peripheral side of the stator core in contact with the can. Reinforced structure of a can of a canned motor, characterized in that one or a plurality of sections are provided, and an annular bulging section which can be fitted tightly with the can receiving section is provided on the can side. 2. The structure of a can of a canned motor according to claim 1, wherein the slit opening is a cooling fluid duct composed of a plurality of duct pieces radially extended from an inner peripheral side to an outer peripheral side.