JP5457236B2 - Canned rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electric machine having a can structure in which a stator is surrounded by a can, and more particularly to a rotating electric machine having a can structure suitable as an electric motor for driving a non-seal pump in which a rotor chamber is filled with a high-pressure pump hydraulic fluid.

Conventionally, a high-pressure motor for driving a non-seal pump with a can structure in which a stator core and a stator winding constituting a stator are surrounded by a can, particularly a large (several thousand kW) rotor chamber having a pole number of 4P to 6P. In induction motors filled with high pressure (1-2 kg / mm ² ) pump hydraulic fluid, eddy current loss caused by magnetic flux penetrating the can is reduced, high internal pressure conditions are tolerated, and high airtightness is required. .

  In such an induction motor with a can structure, in order to reduce the can loss (eddy current loss), it is preferable to use a can made of an insulating material such as a resin material, and further to a high-pressure pump hydraulic fluid that fills the rotor chamber. As a structure for withstanding, it is conceivable to employ fiber reinforced plastic (FRP) as a material constituting the can. In addition, since the rotor chamber is filled with high-pressure pump hydraulic fluid and the rotor rotates at a high speed, the pump hydraulic fluid flows through the can surface at the same peripheral speed as the rotor. There is a case where erosion due to erosion occurs and wear occurs, and if the degree of wear increases, the airtightness of the can may be impaired. Therefore, when FRP is used as the material for the can, the above erosion countermeasure is required.

  Further, since the pump hydraulic fluid in the rotor chamber flows at a high peripheral speed, fluid friction loss occurs in the gap between the can and the rotor. This fluid friction loss is a huge loss depending on the length of the gap to be set, and in general cooling methods such as cooling by forced circulation of rotor chamber fluid, it is necessary to reduce the fluid friction loss from the limit of cooling efficiency. is there.

  Further, when the high-pressure induction motor is used for driving a cooling pump having a non-seal structure of a reactor, the pump hydraulic fluid becomes high temperature, so that heat resistance is required and radiation resistance is also required.

  Conventionally, as a motor having a can structure using FRP as a can material, there are a heat-resistant pressure-resistant permanent magnet synchronous motor disclosed in Patent Document 1 and a canned motor with improved gas tightness disclosed in Patent Document 2.

Japanese Patent Laid-Open No. 5-153749 JP 2001-231213 A

  The pressure resistance and heat resistance of the high-pressure and high-temperature pump hydraulic fluid that fills the rotor chamber, the countermeasure against the erosion resistance against the high-speed flow of the pump hydraulic fluid of the can made of FRP material, and the canned structure considering radiation resistance Patent application 2010-27016 has been filed as a rotating electrical machine. Among them, we propose a multi-layered can that consists of FRP that resists pressure deformation and buckling on the outer diameter side first layer, and a thin metal plate that has excellent fluid tightness and erosion resistance on the inner diameter side second layer. doing. Even if there is no temperature difference between the first layer FRP and the second layer sheet metal, the linear expansion coefficient differs greatly between high-strength resin and metal (for example, there is a difference of 4 times or more between PEEK and Inconel). The higher the value, the longer the resin part tends to be relatively longer. In addition, since the thin metal part generates heat due to eddy current, the internal fluid is circulated through the can part to cool it. However, it is still difficult to keep the thin metal part from the motor frame isothermal, and here also a difference in thermal expansion occurs. .

  The present invention has been made in view of the above points, and is a resin capable of absorbing a difference in thermal expansion generated between a resin part, a thin metal part, and a motor frame so that excessive stress is not generated in each of them. An object of the present invention is to provide a rotating electrical machine including a multilayer structure can having a layer and a thin metal layer.

  In order to solve the above problems, the present invention inserts and fixes a stator core having a stator winding loaded in a cylindrical frame, surrounds the stator winding and the stator core with a can, and surrounds the can with the can In a rotating electrical machine having a can structure in which a rotor is rotatably arranged in a space, the can has a multi-layer structure including a first layer made of a resin and a second layer made of a thin metal plate. A bellows portion or a diaphragm portion is provided at the end of the thin metal plate.

  According to the present invention, in the rotating electric machine having the above canned structure, a spring mechanism for urging the first layer in the axial direction relative to the cylindrical frame is provided at one of the axially opposed portions of the first layer and the cylindrical frame. It is provided.

  Further, in the rotating electric machine having the above-mentioned can structure, the present invention provides an end piece joined to the cylindrical frame at both ends in the axial direction of the cylindrical frame, and both ends of the second layer are connected to the end pieces. It is characterized by being joined.

  Further, in the rotating electrical machine having the above canned structure according to the present invention, both ends of the first layer in the axial direction are opposed to the respective end pieces, and the interval between the end pieces is larger than the axial length of the first layer by a predetermined amount. It is characterized by.

  According to the present invention, in the rotating electric machine having the above canned structure, an O-ring that is elastically deformable on the inner diameter side is inserted into a gap portion between the cylindrical frame on the side where the spring mechanism is provided and the first layer.

  According to the present invention, in the rotating electric machine having the above canned structure, the bellows portion is a cylindrical bellows.

  According to the present invention, in the rotating electric machine having the above canned structure, a split ring type reinforcing wheel is provided between a bellows outer diameter side trough and an inner diameter side of a cylindrical frame facing the trough.

  According to the present invention, in the rotating electric machine having the above canned structure, the diaphragm portion is constituted by a bellows extending in a radial direction.

  In the rotating electric machine having the above canned structure, the diaphragm portion is provided to face the axial end surface of the cylindrical frame, and the bellows constituting the diaphragm portion includes a valley portion on the cylindrical frame side and the valley portion. A strong ring is provided between the axial end faces of the opposing cylindrical frames.

  According to the present invention, in the rotating electric machine having the above canned structure, the bellows portion or the diaphragm portion is made of a thin metal plate thicker than the second-layer thin metal plate.

  According to the present invention, in the rotating electric machine having the above canned structure, the bellows portion or the diaphragm portion is continuously provided with a body portion made of a thin plate metal that is thicker than the thin metal plate of the second layer. It covers the boundary between the frame and the frame.

  According to the present invention, since the bellows portion or the diaphragm portion is provided at the thin metal end portion of the second layer of the can, the bellows portion or the diaphragm portion absorbs the thermal expansion difference between the thin metal plate of the second layer and the frame, The stress generated in the sheet metal of the second layer can be relaxed, and the buckling deformation of the second layer can be prevented.

  Further, according to the present invention, the spring mechanism for urging the first layer in the axial direction with respect to the cylindrical frame is provided at one of the axially opposed portions of the first layer of the can and the cylindrical frame. There is no gap between the first layer, the other end face, and the end face of the cylindrical frame, and the thin metal sheet of the second layer is not pushed into the gap and deformed.

  Further, according to the present invention, the end pieces joined to the cylindrical frame are provided at both ends in the axial direction of the cylindrical frame, and both ends of the second layer are joined to the respective end pieces. Airtightness between the second layer and the cylindrical frame can be maintained.

  Further, according to the present invention, both ends of the first layer in the axial direction are opposed to the respective end pieces, and the interval between the end pieces is larger than the length of the first layer in the axial direction by a predetermined amount. A gap is formed between the end portion of one layer and the end piece, and the axial extension of the first layer can be absorbed by the gap.

  Further, according to the present invention, since the O-ring which can be elastically deformed on the inner diameter side is inserted into the gap between the cylindrical frame on the side where the spring mechanism is provided and the first layer, the radial displacement of the bellows body is reduced. Can be suppressed.

  According to the present invention, since the bellows portion is a cylindrical bellows, the contraction in the axial direction of the second layer made of a thin metal plate can be smoothly absorbed.

  Further, according to the present invention, since the split ring type strong wheel is provided between the bellows outer diameter side trough and the inner diameter side of the cylindrical frame facing the trough, the thickness of the bellows reinforced by the strong wheel , The deformation of the bellows in the radial direction can be prevented, and the stretchability in the axial direction can be maintained.

  In addition, according to the present invention, the diaphragm portion is configured by a bellows that spreads in the radial direction, so that the axial contraction of the second layer made of a thin metal plate can be smoothly absorbed.

  Further, according to the present invention, the diaphragm portion is provided to face the axial end surface of the cylindrical frame, and the bellows constituting the diaphragm portion is a cylindrical frame in which the valley portion on the cylindrical frame side faces the valley portion. Since a strong ring is provided between the axial end faces of the bellows, the thickness of the bellows reinforced by the strong ring can be reduced, the bellows can be prevented from being deformed by the hydraulic pressure of the pump, and the shaft of the second layer made of sheet metal Smoothly absorbs direction shrinkage.

  According to the present invention, the bellows portion or the diaphragm portion is continuously provided with a body portion made of a thin metal plate that is thicker than the thin metal plate of the second layer, and at the body portion, the boundary between the second layer and the frame is provided. Since the portion is covered, for example, even if the boundary portion has minute irregularities due to a difference in thermal expansion or the like, deformation or breakage due to the pump hydraulic pressure at this boundary portion can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view illustrating a schematic configuration of a pump motor including a non-seal pump and a canned induction motor that drives the pump as an example of a rotating electrical machine having a can structure according to the present invention. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG. It is a figure which shows the example of a partial cross section structure of the pump motor shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail. In the present embodiment, an induction motor is described as an example of a rotating electrical machine, but the rotating electrical machine according to the present invention is not limited to this. FIG. 1 is a longitudinal sectional view showing a schematic configuration of a pump motor including a vertical non-seal pump and a canned induction motor for driving the pump as an example of a rotating electrical machine having a can structure according to the present invention. As shown in the drawing, the pump motor is composed of a pump part P and a motor part M. The pump part P is a non-seal pump, and includes a pump casing 1 having a suction port 2 and a discharge port 3, and an impeller 5 fixed to an end of the main shaft 6 is disposed in the pump casing 1. The pump casing 1 is mounted on the impeller side bracket 7. The main shaft 6 is rotatably supported by bearings 16 and 16 disposed above and below.

  The motor unit M is an induction motor, and includes a motor stator 17 inserted and fixed in a cylindrical frame body 11 of the motor frame 10, and a motor rotation fixed to the central portion of the main shaft 6 in the motor stator 17. A child 20 is arranged. Both end portions of the frame main body 11 are attached to a frame side plate 12 on the impeller side and a frame side plate 13 on the anti-impeller side. The frame side plate 12 is fixed to the impeller side bracket 7 of the pump part P. A reinforcing ring portion 18 is integrally provided on the frame side plate 12, and an end portion of the reinforcing ring portion 18 extends to the vicinity of the impeller side end surface of the stator core 17 a of the motor stator 17. The frame side plate 13 is integrally provided with a reinforcing ring portion 19, and the end of the reinforcing ring portion 19 extends to the vicinity of the end face on the side opposite to the impeller side of the stator core 17 a of the motor stator 17.

  21 is a cylindrical can composed of a first layer made of fiber reinforced plastic (FRP) or plastic and a second layer made of a thin metal plate disposed on the inner surface of the first layer, as will be described in detail later. is there. The outer peripheral FRP surface of the can 21 is in close contact with the stator core 17 a of the motor stator 17, the reinforcing ring 18, the reinforcing ring 19, the frame side plate 12, and the inner peripheral surface of the frame side plate 13 constituting the motor frame 10. ing. An O-ring 22 on the impeller side and an O-ring 23 on the anti-impeller side are interposed between the frame side plate 12 and the frame side plate 13. Further, the end portions in the axial direction of the frame side plates 12 and 13 are formed separately from the main bodies of the frame side plates 12 and 13 as annular end pieces 12a and 13a, and joined portions D (FIGS. 2A and 2B). (Refer to FIG. 2), where the end pieces 12a and 13a are part of the frame side plates 12 and 13 which are part of the motor frame 10. 2 (a) and 2 (b), the thin plate metal portion of the second layer 21b of the can 21 is welded to the end pieces 12a and 13a and the welded portion C, and the motor stator 17 is disposed. The stator chamber 14 is sealed. A space surrounded by the cylindrical can 21 is a rotor chamber 15 in which the motor rotor 20 is arranged and rotated.

  In the pump motor having the above-described configuration, a rotating magnetic field is generated by supplying three-phase power having a predetermined frequency and a predetermined voltage from an inverter (not shown) of the power supply device to the stator winding 17b of the motor unit M. The child 20 rotates. Thereby, the impeller 5 fixed to the main shaft 6 rotates, and the pump hydraulic fluid sucked from the suction port 2 of the pump casing 1 is discharged from the discharge port 3. At this time, since the pump part P is a non-seal pump, the rotor chamber 15 is filled with pump hydraulic fluid, the hydraulic fluid is agitated by the motor rotor 20, and the can 21 has an inner peripheral surface of the motor rotor 20. A pump hydraulic fluid having a flow rate substantially equal to the peripheral speed flows and a pressure of the pump hydraulic fluid is applied.

  2A and 2B are diagrams showing a partial cross-sectional configuration of the pump motor having the above-described configuration. FIG. 2A shows an end portion on the side opposite to the impeller, and FIG. 2B shows an end portion on the impeller side. As illustrated, the can 21 is a can having a two-layer structure including a first layer 21a and a second layer 21b. As a constituent material of the first layer 21a, PEEK (polyether ether ketone) or PI (polyimide) resin having high heat resistance and mechanical strength is used. Furthermore, in order to increase mechanical strength, FRP is used which is reinforced by arranging reinforcing fibers having high strength such as glass, aramid, carbon long fibers, etc. in the resin. In addition to PEEK and PI, polyesteramide imide, polyhydantoin, isocyanurate-modified polyesterimide, polyamideimide, polyester, and epoxy can also be used as the FRP resin. These resins are commonly resins having high temperature resistance and radiation resistance, and are suitable for applications requiring high temperature resistance and radiation resistance. Among these resins, PEEK and PI are particularly used in nuclear power plants, and PEEK or PI is particularly suitable for use in nuclear power plants.

  The second layer 21b of the can 21 is a thin metal plate disposed in close contact with the inner peripheral surface of the first layer 21a. In this way, by providing the second layer 21b made of a thin metal plate in close contact with the inner peripheral surface of the first layer 21a, it is possible to secure a higher air density and to prevent the flow of the pump hydraulic fluid in the can 21 from wear. It contacts the inner peripheral surface of the second layer 21b made of a thin metal sheet, and can prevent wear (erosion) due to the flow of the pump working fluid on the inner peripheral surface of the can 21.

  As described above, by providing the second layer 21b in which the thin plate metal is disposed in close contact with the inner peripheral surface of the first layer 21a made of FRP, the can 21 has a can loss (eddy current loss). ) Occurs. However, if the thickness of the thin metal plate is 0.05 mm to 0.1 mm, for example, the can loss of the commonly used metal can thickness 0.2 mm to 0.5 mm is 1/10 to 1 / 2 can loss. In addition, even when conductive carbon fibers are arranged in the resin layer, can loss (eddy current loss) occurs, but the volume resistivity of FRP with carbon fibers arranged is about 100 times that of stainless steel or the like. Therefore, if the can 21 has a constant thickness, it is clear that the can loss of the FRP portion where the carbon fiber is arranged can be significantly reduced to 1/100 of stainless steel or the like.

  If a thermosetting PI resin is used as the resin forming the first layer 21a of the can 21 and a dense structure with few voids is formed by evacuation and pressure heat curing during the resin molding process, airtightness and water-stopping properties are achieved. A high first layer 21a can be formed. The tensile strength in the circumferential direction of the first layer 21a made of FRP reinforced with fibers made of aramid resin is equivalent to about 3 times that of a metal material such as stainless steel.

In the can 21 having such a multilayer structure, a difference in linear expansion coefficient becomes a problem. For example, PI and PEEK have a linear expansion coefficient of about 50 × 10 ⁻⁶ [/ ° C.], and Inconel suitable for the second layer has a high coefficient of linear expansion of about 12 × 10 ⁻⁶ [/ ° C]. If the can length is 1000 mm and the average temperature of the can during motor operation is 75 ° C., the resin and metal having the same length at normal temperature (25 ° C.) will have δ = 1000 × (75.25) × at the operating temperature. An elongation difference of (50.12) × 10 ⁻⁶ = 1.9 mm occurs. In this embodiment, since the resin portion (first layer 21a) of the can 21 is composed of FRP, the linear expansion coefficient with the thin metal part (second layer 21b) can be adjusted by adjusting the direction and density of the long fibers. Although it is possible to make the difference smaller than this example, it is difficult to match the linear expansion coefficients of the two.

  Further, since the thin metal part of the second layer 21b of the can 21 generates heat due to eddy current, the internal fluid is circulated through the can part to cool it. However, even if cooling is performed, it is inevitable that the thin plate metal part becomes hotter than the motor frame 10. This temperature difference also causes a difference in thermal expansion between the second layer 21b, which is a thin metal plate, and the motor frame 10. Unless the stress generated by the difference in thermal expansion is alleviated, the second layer 21b made of a thin metal plate that is particularly fragile and has the smallest displacement absorption capability is buckled, and the hermetic sealing property of the can 21 is destroyed. There is a possibility that.

  In the present embodiment, the second layer 21b made of a thin metal plate of the can 21 and the frame side plates 12 and 13 are joined via the bellows portion 21c in at least one of the longitudinal directions (here, the side opposite to the impeller). The bellows portion 21c absorbs a difference in thermal expansion between the thin plate metal portion of the second layer 21b and the frame main body 11 of the motor frame 10, and relieves stress generated in the thin plate metal portion of the second layer 21b. In FIG. 2A, one end in the longitudinal direction of the thin metal plate of the second layer 21b is welded to the bellows portion 21c at a position A. As shown in FIG. 2B, the other end of the thin plate metal portion of the second layer 21b is welded to the end piece 12a on the impeller 5 side. The end pieces 12a and 13a are welded to the frame side plates 12 and 13 at a point D, respectively. In this way, one end of the thin metal portion of the second layer 21b is joined to the frame side plate 12 on the impeller side via the end piece 12a, and the end of the other bellows portion 21c is welded to the end piece 13a. The end pieces 12a and 13a are welded to the frame side plate 12 on the impeller side and the frame side plate 13 on the side opposite to the impeller at the position D, respectively.

  The thin metal part of the second layer 21b of the can 21 has a thickness of 0.05 to 0.1 mm, for example, and the plate thickness of the bellows part 21c is about 1 mm, for example. Since the welded portion C (the welded portion between the thin plate metal portion of the second layer 21b and the end piece 12a and the bellows portion 21c and the end pieces 12a and 13a) is a thin plate joined, non-filler welding is used. In order to perform reliable joining while minimizing the deformation of the base material without using a filler material (filler), the welded portion C is formed by extending the inner surface of the end piece 13a in the axial direction so that the end piece 13a is tapered. Is forming. In addition, a first layer 21a composed of the FRP portion of the can 21 is installed so as to be sandwiched between both end pieces 12a and 13a. The distance between the axial end faces of both end pieces 12a, 13a is slightly longer than the axial length of the first layer 21a, and the end piece 12a, 13a and the end face of the first layer 21a have a shaft on one side facing each other. A direction gap E is generated. The gap E absorbs the axial extension of the first layer 21a made of resin.

  Since the second metal layer 21b on the inner diameter side of the resin first layer 21a is very thin, if there is an axial gap between the first layer 21a and the end piece 13a, a thin plate is formed in the gap E due to pressure load. There is a possibility that the second layer 21b made of metal may bite and deform. In order to prevent this, the inner diameter side of the constituent part of the gap E between the end piece 13a and the resin first layer 21a is not the second layer 21b itself made of a thin metal plate, but is thicker than the second layer 21b. The body of the bellows part 21c that is difficult to deform is covered. Further, an elastic O-ring 24 may be inserted into the gap E so that axial deformation is possible and radial displacement of the body of the bellows 21c can be suppressed.

  In addition, the constituent end piece 13a of the gap E and the first resin layer are formed so that an axial gap does not occur at the contact portion between the first resin-made layer 21a and the end piece 12a in the other axial direction of the constituent part of the gap E. A spring mechanism 25 that is urged in the axial direction is inserted between the spring 21a and 21a. As a result, the first layer 21a made of resin is always pressed against the end face of the end piece 12a on the other axial side of the constituent part of the gap E so that no gap is generated. A plurality of the spring mechanisms 25 may be equally arranged in the circumferential direction, or a single spring mechanism having substantially the same diameter as the first layer 21a may be used. Moreover, although the groove | channel which inserts the spring mechanism 25 in the figure is provided in the end piece 13a, you may provide a groove | channel on the 1st layer 21a side made from resin (FRP).

  The bellows portion 21c is formed or processed into a wave shape of a continuous mountain or valley, but the thickness of the bellows portion 21c is appropriately reduced in order to facilitate the axial displacement of the second layer 21b made of a thin metal plate. Therefore, it is necessary to design the spring strength low. Therefore, the strengthening wheel 26 is mounted on the outer peripheral side so that the bellows portion 21 c is not deformed by the pressure of the rotor chamber 15. In general, when a relatively thin bellows is used, a strong ring is attached on the outer peripheral side so as not to be deformed by the pressure inside the bellows (in this embodiment, the pressure of the motor rotor chamber 15). Sometimes. A normal strong wheel is a ring type continuous in an integral circumferential direction, and supports pressure load by hoop stress. Since the strong ring of the integral ring structure cannot be mounted after the bellows portion 21c is molded, the strong ring 26 is mounted on a parallel cylinder that is a bellows material, and is integrally molded in a corrugated mold. However, in the case of the strong wheel 26 of the present invention, the end piece 13a that is in close contact with the outer peripheral side of the bellows portion 21c holds the hoop stress. Therefore, the reinforcing wheel 26 may be a split ring and can be mounted after the bellows portion 21c is formed.

  On the outer peripheral side of the first layer 21a made of FRP of the can 21, near the both end surfaces in the axial direction, two each between the first layer 21a and the frame side plates 12, 13 (or the reinforcing ring portions 18, 19). O-rings 22a and 23a and backup rings 22b and 23b are installed in combination. Even if the O-ring breaks the second layer 21b made of thin metal and the high pressure fluid in the rotor chamber 15 enters between the first layer 21a made of FRP and the end piece 13a, the high pressure fluid Is prevented from reaching the stator core. Further, on the inner peripheral surfaces of the frame side plates 12 and 13, leak pressure detection holes 27 and 28 are provided near both ends in the axial direction and closer to the respective axial end surfaces than the O-rings 22 and 23. The breakage of the second layer 21b and the bellows portion 21c made of a thin metal plate can be detected by detecting the high-pressure fluid that has entered. A pressure detector (not shown) is connected to each of the detection holes 27 and 28, and the pressure in the detection holes 27 and 28 is constantly monitored, and an alarm is issued when the pressure rises abnormally.

  FIG. 3 is a diagram showing a second embodiment, and shows a partial cross-sectional configuration of the pump motor. 3A shows an end portion on the side opposite to the impeller, and FIG. 3B shows an end portion on the side of the impeller. The second embodiment is different from the first embodiment in that the bellows portion 21d joined in the axial direction to the second layer 21b made of a thin metal plate of the can 21 is not a cylindrical bellows portion but an end piece 13a. It is configured as a bellows portion 21d that extends in the radial direction along the axial end face. In order to form the welded portion C on the bellows portion 21d side, a thin protrusion 13b extending from the axial end surface of the end piece 13a to the end portion of the bellows portion 21d is provided. A plurality of strong wheels 29 having different diameters are provided between the bellows portion 21d and the end piece 13a in the axial direction. The strong wheel 29 can be inserted into the valley of the bellows without being split.

  In the second embodiment, since the bellows portion 21d spreads in the radial direction, the extension of the second layer 21b made of a thin metal plate is not absorbed by the expansion and contraction of the peaks and valleys of the bellows portion 21d, but the bellows portion 21d serves as a diaphragm. Absorbed by functioning. Therefore, although the bellows is formed in the present embodiment, a different shape can be adopted as long as the shape functions as a diaphragm.

  4A and 4B are diagrams showing a modification of the first and second embodiments. FIG. 4A is a cross-sectional configuration of the end portion on the anti-impeller side, and FIG. 4B is an end portion on the impeller side. The cross-sectional structure of is shown. A thick plate portion 21e thicker than the thin plate metal of the second layer 21b is also bonded to the side where the bellows portion 21c of the second layer 21b made of the thin plate metal of the can 21 is not bonded, and the thick plate portion 21e is made of FRP. The contact portion E between the first layer 21a and the end piece 12a is covered. The thin metal sheet of the second layer 21b is very thin, and if there is any unevenness on the surface that is in contact with the outer peripheral side (actually pressed by the pressure of the rotor chamber 15), it may cause damage. As shown in FIG. 4, since the member thicker (about 1 mm) than the thin plate metal of the second layer 21b covers the boundary portion (contact portion E) between the first layer 21a made of FRP and the end piece 12a, this boundary portion, for example. Even if minute irregularities occur due to a difference in thermal expansion or the like, damage to the thin metal plate (thick plate portion 21e) can be suppressed.

  FIG. 5 is a view showing a modification of the first and second embodiments. FIG. 5 (a) is a cross-sectional configuration of the end portion on the anti-impeller side, and FIG. 5 (b) is an end portion on the impeller side. The cross-sectional structure of is shown. The end piece is integrated with the frame side plate 12 or 13. When the end piece on the side where the spring mechanism 25 is provided is integrated with the frame side plate 13, unlike FIGS. 2 and 3, the position where the pressure detection hole for detecting the leak pressure is provided is not the position facing the end piece. As shown in FIG. 5B, it is necessary to move to a position facing the first layer 21a made of FRP.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Can be modified. Note that any shape or structure not directly described in the specification and drawings is within the technical scope of the present invention as long as the effects of the present invention are achieved. For example, in the above embodiment, the resin layer constituting the first layer 21a of the can 21 is made of FRP. However, if there is no problem in strength, a simple resin-only structure may be used.

  In the present invention, a can of a rotating electric machine having a can structure is constituted by a first layer 21a made of fiber reinforced plastic or plastic, and a second layer 21b made of a thin metal plate disposed on the inner surface of the first layer. Since the bellows portion 21c is provided at the end of the thin metal portion of the two layers 21b, it is excellent in reducing fluid friction loss, pressure resistance and heat resistance, and can solve the problem due to the difference in thermal expansion of each member. It can be used to provide a rotating electric machine having a structure.

DESCRIPTION OF SYMBOLS 1 Pump casing 2 Suction port 3 Discharge port 5 Impeller 6 Main shaft 10 Motor frame 11 Frame main body 12 Impeller side frame side plate 12a End piece 13 Anti-impeller side frame side plate 13a End piece 14 Stator chamber 15 Rotor chamber 16 Bearing 17 Motor stator 18 Reinforcement ring part 19 Reinforcement ring part 20 Motor rotor 21 Can 21a First layer 21b Second layer 21c Bellows part 21d Bellows part 21e Thick plate part 22a O-ring on impeller side 22b Backup ring 23a Anti-blade Car side O-ring 23b Backup ring 24 O-ring 25 Spring mechanism 27 Detection hole 28 Detection hole P Pump part M Motor part

Claims (11)

A stator core loaded with a stator winding is inserted and fixed in a cylindrical frame, the stator winding and the stator core are surrounded by a can, and a rotor is rotatably disposed in a space surrounded by the can In the canned rotating electrical machine,
The can has a multilayer structure composed of a first layer made of a resin and a second layer made of a thin metal plate, and a bellows portion or a diaphragm portion is provided at an end portion of the thin metal plate of the second layer. A rotating electrical machine with a canned structure. The rotating electrical machine having a canned structure according to claim 1,
A canned structure characterized in that a spring mechanism for urging the first layer in the axial direction with respect to the cylindrical frame is provided at one of the axially opposed portions of the first layer and the cylindrical frame. Rotating electric machine. The rotating electrical machine having a canned structure according to claim 1 or 2,
End pieces joined to the cylindrical frame are provided at both axial ends of the cylindrical frame, and both ends of the second layer are joined to the end pieces. Rotating electric machine with structure. The rotating electrical machine having a canned structure according to claim 3,
Both ends of the first layer in the axial direction are opposed to the end pieces, and a distance between the end pieces is larger by a predetermined amount than an axial length of the first layer. Rotating electric machine. The rotating electrical machine having a canned structure according to claim 2,
A rotating electric machine having a canned structure, wherein an O-ring that is elastically deformable on an inner diameter side is inserted into a gap portion between the cylindrical frame on the side where the spring mechanism is provided and the first layer. The rotating electrical machine having a canned structure according to any one of claims 1 to 5,
The bellows portion is a cylindrical bellows. The rotating electrical machine having a can structure according to claim 6,
A rotating electric machine having a canned structure, wherein a split ring type strong wheel is provided between the bellows outer diameter side trough and the inner diameter side of the cylindrical frame facing the trough.   6. The rotating electrical machine with a canned structure according to claim 1, wherein the diaphragm portion is formed of a bellows extending in a radial direction. The rotating electrical machine having a canned structure according to claim 8,
The diaphragm portion is provided to face the axial end surface of the cylindrical frame, and the bellows constituting the diaphragm portion is an axial direction of the cylindrical frame in which the valley portion on the cylindrical frame side faces the valley portion. A rotating electrical machine having a can structure, characterized in that a reinforcing wheel is provided between end faces. The rotating electrical machine having a canned structure according to any one of claims 1 to 5,
The bellows part or the diaphragm part is made of a sheet metal thicker than the sheet metal of the second layer. The rotating electrical machine having a canned structure according to claim 10,
The bellows portion or the diaphragm portion is continuously provided with a body portion made of a sheet metal thicker than the sheet metal of the second layer, and the body portion covers a boundary portion between the second layer and the frame. A rotating electric machine having a can structure.