JPH06105501A - Can sealing structure of canned motor - Google Patents

Abstract

PURPOSE:To make it possible to maintain air and pressure tightness with high reliability by forming a number of O-ring sealing sections in the direction of the axis of a can, and by filling the space sandwiched between the sealing sections with a highly stable viscous substance or disposing a monitoring means for detecting a sealed state from changes in internal pressure of that space. CONSTITUTION:A bearing 81 for axially supporting a rotating shaft 8 is fitted into a circular recess at the center of a bearing support 9 of a canned motor 2 that drives fluid machinery 1. The outer periphery of a portion of the recess which supports the bearing 81 is cylindrically projected in such a way that the diameter of the projecting outer periphery is slightly smaller than the internal diameter of a metal can 6. Two O-ring grooves are axially cut on the projecting outer periphery, so that two O-ring sealing sections 11 and 12 are formed. A hermetic space along the internal periphery of the can 6 sandwiched between the sealing sections 11 and 12 is filled with a highly reliable viscous substance that deteriorates less with time. Thus, the sealing sections 11 and 12 slidably move at the time of the expansion and retraction of the can 6 in the direction of the axis, and air and pressure tightness can be maintained with high reliability in response to thermal expansion resulting from the sliding movement of the sealing sections.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for sealing both ends of a can incorporated in a can motor directly connected to a fluid machine such as a compressor or a liquid feed pump.

[0002]

2. Description of the Related Art Conventionally, in a canned motor, a cylindrical can is provided in an air gap between a stator core and a rotor along the inner circumference of the stator core to shut off the rotor from the atmosphere side. Due to the hermetically sealed structure, a compressed refrigerant such as ammonia, freon, or helium is installed in the can of the compressor, which is a load of the canned motor, or a bearing portion of a driven machine such as a liquid pressure pump. Invade the space. Therefore, the canned motor side integrated with the compressor is also required to be a pressure resistant container like the compressor.

On the other hand, since the canned motor allows high-density alternating magnetic flux from the stator core and the stator coil to pass through to the rotor, the air gap is designed to have a narrow value as long as the rotation is not hindered. The thickness of the cylindrical can fitted inside must be set to be thin, and must have pressure resistance and deformation resistance due to the sealed structure, and also corrosion resistance of ammonia refrigerant etc. that enters from the load side. Is
It is exposed to extremely severe mechanical and chemical conditions.

[0004]

When the canned motor is small, it suffices to weld both ends of a thin-walled cylindrical can to a reinforcing cylinder by welding, but when the canned motor becomes large, the can is used. Since the amount of heat generated by the can increases, the thermal expansion of the can becomes larger than the thermal expansion of the stator core, the reinforcing cylinder, and the like that retain the heat. And, the thermal expansion can be made to enter the stator ring groove with respect to the expansion in the outer peripheral direction, but there is no escape place for the expansion in the axial direction, and the welding process of the can and its Since there is a manufacturing difficulty in finishing the inner circumference to a perfect circle, an O-ring seal in which an O-ring groove is formed by forming a O-ring groove in the bearing support that fixes the bearing is formed. A stopper is provided to allow escape in the axial direction.

On the other hand, the can is formed by welding a thin metal plate into a tubular shape. With the increase in capacity of the canned motor, in other words, the larger diameter of the can, in other words, welding of the thin cylindrical can and Skill level is required for machining such as perfect circular finishing in the can. Since the can is a pressure resistant container as described above, pressure resistance and leakage inspection are required after the machining.

However, although the welded portion of the can can be easily inspected, it is difficult to inspect the O-ring sealing portion because the quality of the O-ring sealing portion appears only after the assembly of the can and the bearing portion, and the airtightness of the sealing portion is high. Problems also occur due to changes over time during use, not at the time of assembly. Therefore, it is impossible to inspect them accurately at the time of assembly. on the other hand,
It is also considered that the can is made of, for example, a carbon-based synthetic resin excellent in electrical insulation and corrosion resistance.

It is true that the resin has no rust and has less thermal expansion than metal, but it cannot be fixed to the inner circumference of the stator core and the reinforcing cylinder by welding. Therefore, after all, it is unavoidable to use the O-ring sealing structure at both ends of the can, and when the O-ring sealing structure is used for the synthetic resin, there is a problem such as roundness and the carbon-based structure. The synthetic resin is still under development, and it is quite difficult to construct a thin-walled can having a large diameter and high roundness, and at present, it is still necessary to rely on a metal can.

Therefore, according to the first aspect of the present invention, a can made of a metal can and a sealing structure using an O-ring can be employed, and the can and pressure resistance can be maintained with high reliability even when the can has a large diameter. It is an object of the present invention to provide a sealing structure of. The invention according to claim 2 achieves simplification of the pressure resistance and airtightness test of the O-ring sealing portion at the assembly stage of the motor, and at the same time, the sealing mechanism due to deterioration of airtightness or deterioration of O-ring that occurs during operation It is an object of the present invention to provide a can-sealing structure in which deterioration due to change with time can be detected in a highly reliable and predictive manner before airtightness and pressure resistance are lost.

[0009]

The invention according to claim 1 is
In order to obtain a highly reliable sealing structure even when the diameter of the can is increased, a plurality of O-ring sealing portions including O-ring grooves and O-rings formed on the inner peripheral side of the can are interposed in the can axial direction. In addition, the space sandwiched between the sealing parts is filled with a viscous substance that is highly stable and has little change over time.

The invention according to claim 2 is the same as the above-mentioned invention in that a plurality of O-ring sealing portions are provided in the can axis direction, but the present invention is directed to a space portion sandwiched between the sealing portions. The internal pressure is taken out to the monitoring body side through a conduction hole formed in the support body having the O-ring interposed, and the sealed state of the O-ring can be detected by the change in the internal pressure detected by the monitoring body side. It is a feature.

[0011]

In the invention described in claim 1, since the sealing portions provided at both ends of the can of the canned motor are a plurality of O-rings interposed along the axial direction, the canned motor of the large capacity can Expansion and contraction in the can axis direction caused by the heat generated can be easily allowed, and a double sealing structure can be obtained by a plurality of O-ring sealing portions arranged in the can axis direction. Further, since the viscous substance which is less stable and highly stable is filled in the space sandwiched by the sealing parts, a cylindrical ring-shaped sealing space is formed by the viscous substance, and the two O-ring seals are formed. Even if the viscous substance causes thermal expansion or a slight roundness defect together with the stopper, it is possible to guarantee the airtightness and pressure resistance with high reliability, and as a result, highly reliable sealing is achieved even when the can has a large diameter. A stop structure can be obtained.

According to the second aspect of the present invention, a portion of the outer peripheral portion of the bearing in which the O-ring is interposed, such as the outer peripheral portion of the O-ring and the inner periphery of the can which is not visible from the outside, is sealed by the pair of O-rings. Since the internal space of the space is constantly monitored by using the through hole formed in the interposition support of the O-ring while forming the sealed space by the stopper, the motor is assembled at the stage described above. By easily grasping the pressure resistance and airtightness of the O-ring sealing portion, and by constantly or appropriately grasping the change state of the internal pressure during operation, it is possible to reduce the internal pressure even when the sealing portion is not completely damaged. It is possible to easily and reliably predict the deterioration of the sealing mechanism due to the deterioration with time due to the deterioration of the airtightness or the O-ring before the airtightness and the pressure resistance are lost.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, unless otherwise specified, and are simply It is only an example of explanation. FIG. 1 is a cutaway sectional view of a canned motor directly connected to a compressor and other fluid machines, which corresponds to the invention according to claims 1 and 2. In the drawing, 1 is a fluid machine such as a compressor or a liquid pressure pump driven by a canned motor 2, 3 is a stator coil wound around a rotor core 4 of the canned motor, and 5 are arranged at both axial ends. A rotor which is supported by the bearing 81 via a rotary shaft 8 and rotates integrally with the rotary shaft 8, and 6 is a can made of a thin cylindrical body fixedly mounted on the inner peripheral surface of the stator core 4. 7 has an inner diameter substantially the same as the inner peripheral surface of the stator core 4, and a bearing support 9 is provided on the shaft end side.
Reinforcing cylinders having flanges that are abutted and fixed to the inner wall of the stator core 4, and are arranged symmetrically on both sides of the stator core 4 in the axial direction.

Reference numeral 2O is a cylindrical motor frame on which the stator core 4 is fixed, and 9 is an end plate-shaped bearing support disposed on both end sides of the motor frame via flanges of a reinforcing cylinder. , The three members are integrally fixed by bolt connection, the bearing 81 supporting the rotating shaft 8 is fitted in the central circular recess of the support 9, and the outer peripheral side of the bearing 81 support part is fixed. The O-ring grooves 110 and 111 are axially formed in the protruding portion 10 while protruding in a cylindrical shape having a diameter slightly smaller than the inner diameter of the can 6.
Two O-ring sealing parts 11 and 12 are formed by interposing O-rings 11 a and 12 a on the No. 1.

As shown in FIG. 3, the sealing portion 11,
A through hole 14 opened on the peripheral surface of the cylindrical protruding portion 10 sandwiched by 12 is penetrated to the end surface or the outer peripheral surface of the support body 9 communicating with the outside air.

FIG. 2 shows a main part configuration according to an embodiment of the invention as set forth in claim 1, in which the outer circumference of the cylindrical protrusion 10 of the bearing support 9 in which the bearing 81 is fitted is slightly smaller than the inner diameter of the can 6. A small diameter is set so that the inner circumference of the can can be fitted, and two O's are formed on the outer circumference of the protruding portion 10 along the direction of the can axis.
The ring grooves 110 and 111 are abraded, and the ring grooves 110 and 111 are
The two O-rings are made by interposing O-rings 11a and 12a on 111.
The ring sealing parts 11 and 12 are formed. At this time, the depth of the O-ring grooves 110 and 111 is equal to that of the O-rings 11a and 12a.
Of the O-ring 11 between the inner circumference of the can sandwiched by the O-ring sealing portions 11 and 12 and the cylindrical protrusion 10.
A ring-shaped hermetically sealed space 13 sealed in a and 12a is formed, and the space 13 is filled with a viscous substance that is stable over time and highly stable, such as silicon grease 13a. As a result, the sealing function of the O-ring sealing portions 11 and 12 is enhanced, and higher reliability can be maintained.

FIG. 3 shows an embodiment of the present invention as defined in claim 2, wherein two O-ring grooves 1 are axially formed on the cylindrical protrusion 10.
10 and 111 are abraded and O is formed in the ring grooves 110 and 111.
Similar to the above embodiment, the two O-ring sealing portions 11 and 12 are formed by interposing the rings 11a and 12a, and the ring-shaped space portion 13 is formed between the sealing portions 11 and 12. However, in the present embodiment, the conduction hole 14 opened in the peripheral surface of the cylindrical protruding portion 10 sandwiched between the sealing portions 11 and 12 is penetrated to the end surface or the outer peripheral surface of the support body 9 communicating with the outside air, and the conduction The internal pressure of the space can be detected from the outside air side through the hole 14. That is, in this embodiment, the pressure sensor 15 is attached to the outside air side end of the conduction hole 14 through the connecting pipe 16 so that the internal pressure can be constantly monitored from the outside air side. In addition, the space and the conduction hole 14
Alternatively, the connection pipe 16 may be filled with silicon grease and the internal pressure of the grease may be detected.

According to this embodiment, by observing the change in the internal pressure of the space 13 with the pressure sensor 15, not only can the air-tightness of the can sealing parts 11 and 12 after assembly be determined, but also the operation can be performed. Even if the pressure sensor 15 is kept connected to the conduction hole 14 and the internal pressure of the space 13 is constantly monitored, the deterioration of the airtightness due to the change over time may be excessive. This makes it possible to grasp the information and is extremely effective for maintenance inspections and prior repairs.

Next, in the large capacity canned motor as in the present application, the amount of heat generated by the can 1 is large, and the can 1 can be escaped in the stator core due to the expansion due to the expansion in the circumferential direction, but the can 1 contracts in the axial direction. Then, it can be expanded and contracted so that it can slide on the sealing parts 11 and 12 of the can to cope with the expansion.

[0020]

As described above, according to the first aspect of the invention, the airtightness and the pressure resistance can be obtained even when the diameter of the can is increased while adopting the sealing structure of the metal can and the O-ring. It is possible to obtain a can sealing structure that can be maintained with high reliability.

The invention according to claim 2 achieves simplification of pressure resistance and airtightness test of the O-ring sealing portion at the stage of assembling the motor, and also causes deterioration of airtightness and O-ring during operation. Deterioration of the sealing mechanism due to aging can be reliably and predictively detected before airtightness and pressure resistance are lost. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is a cutaway sectional view of a sealed canned motor according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the canned motor of FIG.
It corresponds to the described invention.

FIG. 3 is an enlarged view of an essential part for detecting the internal pressure of the sealing portion according to the embodiment of the present invention, which corresponds to the invention according to claim 2.

[Explanation of symbols]

 2 Canned motor 4 Stator iron core 5 Rotor 6 Can 9 Bearing support 10 Cylindrical protrusion 11, 12 O-ring sealing part 10, 11 13 Space 14 Conduction hole 15 Pressure sensor

Claims (2)

[Claims] 1. A canned motor sealing structure in which both inner peripheral side ends of a can interposed between a stator and a rotor are configured to be able to be sealed via O-ring sealing portions, A can seal for a canned motor, wherein a plurality of O-ring sealing parts are arranged in the can axis direction, and a space between the sealing parts is filled with a highly stable viscous substance with little change over time. Stop structure. 2. A canned motor sealing structure, wherein both ends of an inner side of a can interposed between a stator and a rotor can be sealed via O-ring sealing parts. A plurality of O-ring sealing parts are arranged in the can axis direction, and the internal pressure of the space sandwiched by the sealing parts is taken out to the monitoring body side through a conduction hole formed in a support body having an O-ring interposed therebetween. A can sealing structure for a canned motor, wherein the sealing state of the O-ring can be detected by the change in the internal pressure detected by the monitoring body.