JP2017121123A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable casting frame of a rotary electric machine.SOLUTION: A rotary electric machine includes a rotor having a rotor shaft and a rotor iron core, a stator, a coupling side bearing and a counter coupling side bearing which freely rotatably support the rotor, a coupling side bearing bracket made of cast steel for fixedly supporting the coupling side bearing, a counter coupling side bearing bracket made of cast steel for fixedly supporting the counter coupling side bearing, and a frame 100 made of cast steel which houses the rotor iron core and the stator, and forms a sealed space together with the coupling side bracket and the counter-coupling side bracket. Plural ventilation paths 110 are formed in the frame 100 so as to extend in the axial direction and be spaced from each other in the circumferential direction. The plural ventilation paths 110 are formed so that the thickness of the radially inner portion 110g is larger than the thickness of the radially outer portion 110h for each of the plural ventilation paths 110.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotating electrical machine having a cast steel frame.

  In the explosion-proof type rotary electric machine, the frame is an explosion-proof container. As a method for manufacturing the frame, there are a method using a steel plate and a method using a casting. In the case of the steel plate, the strength is higher than that of the casting, so that the plate thickness can be reduced and the weldability is good. On the other hand, in the case of casting, a great merit is that it can be realized even in a complicated shape.

  The use of an explosion-proof container as a cast frame can reduce the manufacturing cost compared to the steel plate, and the cooling mechanism can be improved by adopting a system that circulates the internal air inside the rotating electrical machine using a complicated frame structure with ventilation passages. be able to. As a result, the output of the rotating electrical machine can be increased.

Japanese Patent No. 2860036

  Conventionally, the frame structure of a large explosion-proof rotary electric machine has a high explosion pressure in the frame, so the cast frame has no or insufficient strength against the explosion pressure. It has been adopted. Since the steel plate frame has cooling fins attached to the outer periphery of the frame by welding, the manufacturing cost is high, and the number of fins that can be welded is limited.

  Further, since a steel plate frame is a steel plate, it is difficult to manufacture a complicated frame structure. For this reason, since it is difficult to improve the cooling performance by the internal air circulation method with a complicated structure, the output of the rotating electrical machine having the steel plate frame is limited.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to make a frame of an explosion-proof container of a rotating electrical machine made of cast steel.

  In order to achieve the above-mentioned object, a rotating electrical machine according to the present invention includes a rotor having a rotor shaft extending in the axial direction and a rotor core provided radially outside the rotor shaft, and a diameter of the rotor. A cylindrical stator that is stationary and fixed on the outside in the direction, a coupling side bearing and an anti-coupling side bearing that rotatably support the rotor, and a coupling side bearing made of cast steel that fixes and supports the coupling side bearing A bracket, an anti-bonding bearing bracket made of cast steel for fixing and supporting the anti-bonding side bearing, the rotor core and the stator are housed, and sealed together with the coupling-side bracket and the anti-bonding side bracket A frame made of cast steel that forms a space, and the frame has a plurality of ventilation paths extending in the axial direction and spaced apart from each other in the circumferential direction, and each of the plurality of ventilation paths has a diameter. Characterized in that it is formed so that the thickness direction inner portion is greater than the thickness of the radially outer portion.

  According to the present invention, the frame of the explosion-proof container of the rotating electrical machine can be made of cast steel.

It is a longitudinal cross-sectional view which shows the structure of the rotary electric machine which concerns on embodiment. It is a side view which shows the external appearance of the rotary electric machine which concerns on embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing an internal gas flow path of the rotating electrical machine according to the embodiment. FIG. 4 is a partial longitudinal sectional view taken along the line IV-IV in FIG. 3 showing the structure of the upper part of the frame of the rotating electrical machine according to the embodiment. It is the fragmentary figure which looked at the ventilation path inlet opening and ventilation path exit opening of the upper part of the flame | frame of the rotary electric machine which concerns on embodiment from the inner side of the flame | frame. It is the fragmentary figure which looked at the ventilation path entrance opening and ventilation path exit opening of the upper part of the flame | frame of the conventional flameproof explosion-proof rotary electric machine from the inner side of the flame | frame. It is a graph which shows the example of the comparison of the stress around the ventilation path inlet opening in this embodiment and the conventional ventilation path outlet opening. It is the fragmentary view which looked at the casting sand discharge hole of the upper part of the flame | frame of the rotary electric machine which concerns on embodiment from the inner side of the flame | frame. It is the fragmentary view which looked at the casting sand discharge hole of the upper part of the flame | frame of the conventional flameproof explosion-proof rotary electric machine from the inner side of the flame | frame. It is a graph which shows the example of the comparison of the stress around a foundry sand discharge hole in this embodiment and the conventional. It is a longitudinal cross-sectional view which shows the structure of the bearing bracket of the rotary electric machine which concerns on embodiment. It is the longitudinal cross-sectional view of the upper half part of the bearing bracket which shows the case of this embodiment which increases thickness to the outer surface side of a bearing bracket, (b) is 10 mm, (c) is 20 mm, (d) is about 30 mm, respectively. The case where the plate | board thickness of a part is increased outside is shown. It is a graph which shows the example of the change of the deformation amount of radial direction at the time of increasing thickness to the outer surface side of a bearing bracket. It is a longitudinal cross-sectional view of the upper half part of the bearing bracket showing the case where the thickness is increased on the inner surface side of the bearing bracket, where (b) is 10 mm and (c) is about 20 mm when the plate thickness of the main body is increased inward. Indicates. It is a graph which shows the example of the change of the deformation amount of radial direction at the time of increasing thickness to the inner surface side of a bearing bracket.

  Hereinafter, a rotating electrical machine according to an embodiment of the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

  FIG. 1 is a longitudinal sectional view showing a configuration of a rotating electrical machine according to the embodiment. FIG. 2 is a side view showing the appearance of the rotating electrical machine according to the embodiment. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing the internal gas flow path of the rotating electrical machine according to the embodiment. The rotating electrical machine 200 includes a rotor 10, a stator 20, a coupling-side bearing bracket 41, an anti-coupling-side bearing bracket 42, and a frame 100. Here, the coupling side bearing bracket 41, the anti-coupling side bearing bracket 42 and the frame 100 are made of cast steel.

  The rotor 10 includes a rotor shaft 11 extending in the rotation axis direction and a cylindrical rotor core 12 provided on the radially outer side of the rotor shaft 11. An inner fan 15 is attached to the rotor shaft 11.

  The stator 20 is disposed on the outer side in the radial direction of the rotor core 12 and is fixedly fixed to a cylindrical stator core 21, and fixed around a slot (not shown) formed in the stator core 21. A child coil 22 is provided.

  The flow of the cooling gas is indicated by arrows in FIG. The cooling gas driven by the inner fan 15 circulates in the sealed space 100a. That is, the cooling gas flows into a vent (not shown) formed in the rotor 10 to cool the rotor 10, then flows into the inner fan 15, and is driven by the inner fan 15. The cooling gas exits the inner fan 15, enters the ventilation path 110 through the ventilation path inlet opening 110 a, flows out from the ventilation path outlet opening 110 b, and flows into the rotor 10 again, so that the cooling gas can be appropriately cooled. is there.

  The rotor shaft 11 is rotatably supported at both ends by a coupling side bearing 31 and an anti-coupling side bearing 32. The coupling side bearing 31 is supported by a coupling side bearing bracket 41. Further, the anti-coupling side bearing 32 is supported by the anti-coupling side bearing bracket 42.

  The frame 100 houses the rotor core 12 and the stator 20. The frame 100, the coupling-side bearing bracket 41, and the anti-coupling-side bearing bracket 42 combine with each other to form a sealed space 100a.

  The frame 100 is formed with an air passage 110 extending in the axial direction at intervals in the circumferential direction. The inner part of the sealed space 100a and each of the ventilation paths 110 are connected by a ventilation path inlet opening 110a and a ventilation path outlet opening 110b. In addition, when casting the frame 100, in order to extract the casting sand to be filled to form the ventilation path 110 after casting, the casting sand discharge hole 110c ( FIG. 8) is formed.

  On the outer surfaces of the frame 100, the coupling side bearing bracket 41, and the anti-coupling side bearing bracket 42, heat dissipating fins 115 are provided at intervals.

  The cooling gas that has passed through the rotor core 12 by the inner fan 15 flows into the ventilation path 110 from the ventilation path inlet opening 110a and passes through the ventilation path 110 in the axial direction through the frame 100 and the fin 115. After exchanging heat with the outside air, it flows out from the ventilation path outlet opening 110b to the coupling side bearing bracket 41 side inside the frame 100 and flows into the rotor core 12 again.

  As shown in FIG. 3, four ventilation paths 110 are formed at intervals of 90 degrees in the circumferential direction. The number of ventilation paths 110 is not limited to four, and may be set based on strength, cooling addition, cooling capacity, and the like. For example, five or more. The cross-sectional shape of the ventilation path 110 is a rectangular shape having a larger width (W) in the circumferential direction than the height (H) in the radial direction, and the four corners are smooth shapes having no corners. The at least one ventilation path 110 is a member of the frame 100, and among the four sides forming the ventilation path 110, a radially inner portion (radially inner portion) 110 g is a radially outer portion ( The plate thickness is larger than (radially outer portion) 110h.

  4 is a partial vertical cross-sectional view taken along the line IV-IV in FIG. 3 showing the structure of the upper part of the frame of the rotating electrical machine according to the embodiment. A portion of the outer surface of the frame 100 where the ventilation path 110 is formed protrudes outward. That is, the inclined part 100d is formed in the part which corresponds to the both ends of the longitudinal direction of the ventilation path 110. As shown in FIG. This is because the ventilation path inlet opening 110a and the ventilation path outlet opening 110b are formed at both ends in the longitudinal direction of the ventilation path 110, respectively.

  Specifically, in order to reduce the flow resistance when flowing into the ventilation path 110 from the ventilation path inlet opening 110a, it is more advantageous to bend 90 degrees twice than to bend 90 degrees once. Similarly, in order to reduce the flow resistance when flowing out from the ventilation path 110 to the ventilation path outlet opening 110b, it is more advantageous to bend 90 degrees twice than to bend 90 degrees once.

  FIG. 5 is a partial view of the ventilation path entrance opening and the ventilation path exit opening at the top of the frame of the rotating electrical machine according to the embodiment as viewed from the inside of the frame. FIG. 6 is a partial view of the ventilation path inlet opening and the ventilation path outlet opening at the top of the frame of a conventional explosion-proof type rotating electrical machine as viewed from the inside of the frame.

  As shown in FIG. 4, at both ends in the longitudinal direction of the ventilation path 110, the frame 100 is not cylindrical but has a truncated cone shape. For this reason, compared with a cylindrical shape, the shape increases stress.

  Conventionally, in order to reduce the flow resistance as much as possible, as shown in FIG. 6, the longitudinal width (H2) of the ventilation path of the ventilation path inlet opening 510a and the ventilation path outlet opening 510b is sufficiently long. Yes. For this reason, when manufacturing a large-sized frame by casting, the tolerance on strength is insufficient or the tolerance on strength cannot be secured.

  In the ventilation path inlet opening 110a and the ventilation path outlet opening 110b in the present embodiment, as shown in FIG. 5, the width (H1) in the longitudinal direction of the ventilation path 110 is shortened, and the height H ( It is almost equal to FIG. In addition, it is not exact | strict in this case, and it should just correspond, for example with the error of about several percent. Thus, by shortening the width in the longitudinal direction of the ventilation path 110, it is possible to compensate for a decrease in strength due to the shape of the outer surface of the frame 100, and to ensure a tolerance in strength even in the case of casting.

  FIG. 7 is a graph showing an example of comparison of stresses around the ventilation path inlet opening and the ventilation path outlet opening in the present embodiment and the conventional one. The vertical axis represents the relative stress value in the example of the present embodiment when the stress in the conventional example is 100. In this example, it is reduced to about 60%. In this way, by reducing the length of the air passage inlet opening 110a and the air passage outlet opening 110b in the axial direction of the rotor shaft 11, that is, the longitudinal direction of the air passage 110, the stress around these openings can be greatly reduced. it can.

  FIG. 8 is a partial view of the casting sand discharge hole at the top of the frame of the rotating electrical machine according to the embodiment as seen from the inside of the frame. FIG. 9 is a partial view of the casting sand discharge hole at the top of the frame of a conventional explosion-proof explosion-proof electric machine as seen from the inside of the frame. The conventional foundry sand discharge hole 510c has a shape close to a rectangle.

  FIG. 10 is a graph showing an example of a comparison of stress around the foundry sand discharge hole in the present embodiment and the conventional one. The vertical axis represents the conventional case as 100, and shows a comparison with this embodiment. In the example of this embodiment, the vertical axis is reduced to about 3/4. That is, stress can be reduced by making the opening shape of the foundry sand discharge hole 110c elliptical.

  FIG. 11 is a longitudinal sectional view showing the structure of the bearing bracket of the rotating electrical machine according to the embodiment. Hereinafter, at least one of the coupling-side bearing bracket 41 and the anti-coupling-side bearing bracket 42 will be collectively referred to as a bearing bracket. Each of the coupling-side bearing bracket main body 41a and the anti-coupling-side bearing bracket main-body 42a has a configuration in which fins 115 are provided outside the coupling-side bearing bracket main-body 41a and the anti-coupling-side bearing bracket main-body 42a.

  FIG. 12 is a longitudinal sectional view of the upper half portion of the bearing bracket showing the case of the present embodiment in which the thickness is increased on the outer surface side of the bearing bracket, where (b) is 10 mm, (c) is 20 mm, and (d) is The plate thickness of the main body is increased outward by about 30 mm. For simplicity, the fins 115 are not shown.

  FIG. 13 is a graph showing an example of changes in the amount of deformation in the radial direction when the thickness is increased on the outer surface side of the bearing bracket. It can be seen that when the plate thickness is increased outward, the amount of deformation clearly decreases.

  FIG. 14 is a longitudinal sectional view of the upper half portion of the bearing bracket showing the case where the thickness is increased on the inner surface side of the bearing bracket. (B) is 10 mm, (c) is about 20 mm, and the plate thickness of the main body is set to the inside. It has increased to. For simplicity, the fins 115 are not shown in the same manner.

  FIG. 15 is a graph showing an example of a change in the amount of deformation in the radial direction when the thickness is increased on the inner surface side of the bearing bracket. As shown in FIG. 15, the amount of deformation hardly changes.

  As described above, the main body portion of the bearing bracket in this embodiment, that is, the coupling-side bearing bracket main body portion 41a and the anti-coupling-side bearing bracket main body portion 42a can reduce the deformation amount by increasing the plate thickness to the outside. it can.

[Other Embodiments]
As mentioned above, although embodiment of this invention was described, embodiment is shown as an example and is not intending limiting the range of invention. The embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The embodiments and the modifications thereof are included in the scope of the invention and the scope of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Rotor, 11 ... Rotor shaft, 12 ... Rotor core, 15 ... Inner fan, 20 ... Stator, 21 ... Stator core, 22 ... Stator coil, 31 ... Coupling side bearing, 32 ... Anti-coupling side bearing , 41 ... coupling side bearing bracket, 41a ... coupling side bearing bracket main body, 42 ... anti-coupling side bearing bracket, 42a ... anti-coupling side bearing bracket main body, 100 ... frame, 100a ... sealed space, 100d ... inclined portion, 110 ... ventilation path, 110a ... ventilation path inlet opening, 110b ... ventilation path outlet opening, 110c ... casting sand discharge hole, 110g ... radial inner part, 110h ... radial outer part, 111 ... closing plate, 115 ... fin, 200 ... Rotating electric machine, 510a ... ventilation path inlet opening, 510b ... ventilation path outlet opening, 510c ... casting sand discharge hole

Claims (4)

A rotor having a rotor shaft extending in the axial direction and a rotor core provided radially outside the rotor shaft;
A cylindrical stator that is arranged on the radially outer side of the rotor and fixed stationary;
A coupling-side bearing and an anti-coupling-side bearing that rotatably support the rotor;
A joint-side bearing bracket made of cast steel for fixedly supporting the joint-side bearing;
An anti-bonding side bearing bracket made of cast steel for fixedly supporting the anti-bonding side bearing;
A frame made of cast steel that houses the rotor core and the stator and forms a sealed space in combination with the coupling side bracket and the anti-coupling side bracket;
With
The frame is formed with a plurality of ventilation passages extending in the axial direction and spaced apart from each other in the circumferential direction, and the thickness of the radially inner portion of each of the plurality of ventilation passages is greater than the thickness of the radially outer portion. A rotating electric machine characterized in that it is formed. A plurality of ventilation paths are formed in the frame extending in the axial direction and spaced apart from each other in the circumferential direction, and a ventilation path inlet opening and a ventilation path outlet opening are formed for each of the plurality of ventilation paths,
2. The rotation according to claim 1, wherein widths of the axial direction of the ventilation path inlet opening and the ventilation path outlet opening coincide with a radial width of the ventilation path within a predetermined error range. Electric.   3. The casting sand discharge hole after casting the frame is formed in the frame, and the shape of the casting sand discharge hole is formed in an elliptical shape. Rotating electric machine.   Each of the coupling side bracket and the anti-coupling side bracket has a heat dissipation fin provided on the outer surface, and at least one of the coupling side bracket and the anti-coupling side bracket is an outer surface in a portion where the fin is provided. The rotating electrical machine according to any one of claims 1 to 3, wherein the thickness is increased to the side.

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