Sectional type laminated magnet yoke with magnet yoke inter-section air guide structure

Abstract

The invention belongs to the field of hydro-generators, and discloses a segmented laminated magnet yoke with a magnet yoke inter-segment air guide structure, which consists of magnet yoke punching sheets, an upper-segment magnet yoke pressing plate, an inter-segment air guide structure, a lower magnet yoke pressing plate, a ventilation slotted vane, a magnet yoke tensioning screw rod, a nut, an adjusting gasket, a locking block, a magnet yoke key, a clamping key structure, a brake ring and a wind shield structure. According to the invention, eddy current loss can be effectively reduced, generator efficiency is improved, overall stability of the magnet yoke is improved, installation and transportation difficulties of the magnet yoke are reduced, maintenance and repair are facilitated, the air guide structure optimizes a ventilation path, air volume loss is reduced, and air flow efficiency is improved. Therefore, air can be uniformly blown to a magnetic pole, a stator coil and other parts through each ventilation duct, the phenomenon of non-uniform heat dissipation of a part of stator bars is relieved, the operation stability of the generator is improved, and the service life of the generator is prolonged.

Description

Technical Field

[0001] The invention relates to the field of hydro-generators, and in particular to a segmented laminated yoke with an inter-segment wind guide structure of the yoke. Background Art

[0002] The single-stage capacity of large-scale hydroelectric generators has been increasing, and has now reached the million-kilowatt level. It can continuously and stably output a large amount of electric energy for a long time. As a key equipment of a hydropower station, its performance directly affects the overall operating efficiency and stability of the power station. The rotor part of the generator is the main component for energy conversion and torque transmission. The yoke, as one of the important components of the generator rotor, is an important part of the generator magnetic circuit and a structural component for fixing the magnetic poles. At the same time, the ventilation groove in the yoke is an important part of the generator ventilation system. The cold air flows through the gap between the magnetic poles and the stator part through the rotor yoke wind groove, and the return air is used to achieve a circulating cooling effect. Due to the requirements of high power and high energy output, the rotor part of large-scale hydroelectric generators is larger in size and weight, the structure is more complex, and the generator has higher requirements for the cooling system. The yoke of a large hydroelectric generator is stacked with high-strength steel plates and divided into two sections, which can effectively reduce eddy current losses and improve the efficiency of the generator. At the same time, the segmented form can effectively control the stability of the overall structure and facilitate installation, transportation and maintenance. However, the segmented laminated yoke structure in the currently operating large units needs to meet the conditions of segmented installation, so a large gap is generated between the yoke segments, which reduces the air gap pressure between the segments and makes it easier for cold air to circulate in this gap, thereby affecting the ventilation path of air flowing through the yoke, reducing the efficiency of air flow, making the cooling effect uneven, and easily causing local stator wire rods and core temperatures to overheat. If the stator part does not dissipate heat evenly, it may deform, thus affecting the operating stability and service life of the generator. Therefore, improving the ventilation efficiency of the segmented laminated yoke and optimizing the air flow path are important directions for current research. Summary of the invention

[0003] In view of this, it is urgently needed for the present invention to disclose a segmented laminated yoke with a stable structure and an inter-segment air guiding structure that is easy to install. The technical solution of the present invention is specifically described as follows: the present invention consists of a yoke punching sheet, an upper yoke pressure plate, an inter-segment air guiding structure, a lower yoke pressure plate, a ventilation slot sheet, a yoke tightening screw, a nut, an adjustment gasket, a locking block, a yoke key, a key structure, a brake ring, and a wind shield structure. The yoke punching sheets are staggered and stacked and fastened with the upper yoke pressure plate and the ventilation slot sheet through a yoke tightening screw and a nut to form an upper section of the laminated yoke. The yoke punching sheets are staggered and stacked and fastened with the inter-segment air guiding structure, the lower yoke pressure plate, and the ventilation slot sheet through a yoke tightening screw and a nut to form a lower section of the yoke. The yoke key is driven into the two sections of the yoke and fastened to the rotor bracket. The key structure fixes the yoke key. The brake ring is assembled at the lower end of the yoke through the yoke tightening screw, the nut, and the locking block to form a whole. The windshield structure is located at the upper end of the magnetic yoke and is welded to the windshield of the rotor bracket.

[0004] In the above-mentioned segmented laminated yoke with a yoke inter-segment wind guide structure, the yoke punching sheet is fan-shaped, and a T-tail groove is processed at the outer diameter for connection with the pole T-tail. A small inter-pole dove-tail groove is processed between the T-tail grooves to connect the inter-pole connection device to form a passage between each pole. A keyway is processed at the center line of the T-tail groove on the inner diameter of the punching sheet, and a pole key is driven into the keyway to prevent the pole punching sheet from being offset during the operation of the unit and affecting the stability of the unit. Four rows of screw holes are opened on the yoke punching sheet for connecting and fixing each punching sheet.

[0005] In the above-mentioned segmented laminated yoke with an inter-segment wind guide structure of the yoke, the structures of the upper yoke pressure plate and the lower yoke pressure plate are similar to the yoke punching sheet, and their outer diameter dimensions are slightly smaller than the yoke punching sheet, and their inner diameter dimensions are slightly larger than the yoke punching sheet. The upper yoke pressure plate is respectively processed with a T-tail groove, a small dove-tail groove between poles, a keyway and a screw hole at the same position as the yoke punching sheet, and the size is slightly larger. The lower yoke pressure plate is not processed with a T-tail groove, but a pole keyway is processed at the T-tail position of the yoke punching sheet for driving a pole key to achieve a tight connection between the pole and yoke.

[0006] In the above-mentioned segmented laminated yoke with an inter-segment wind guide structure of the yoke, the inter-segment wind guide structure is welded by an upper yoke pressure plate and an "L"-shaped wind guide belt. The "L"-shaped wind guide belt is symmetrically welded at the inner diameter to form an inlet opening. The inter-segment wind guide structure is installed at the upper end of the lower yoke, used as a pressure plate and fastened to the yoke punching sheet together with the lower yoke pressure plate. Its installation position is between the segments of the segmented yoke, and has a large gap to form a first ventilation groove. After the installation is completed, a support block is welded in the middle position to support the upper yoke. The inter-segment wind guide structure can optimize the ventilation path of the rotor yoke, and the opening design of the wind guide belt is conducive to the installation of the upper yoke.

[0007] In the above-mentioned segmented laminated yoke with the yoke inter-segment wind guide structure, the ventilation slots are welded by yoke punching sheets, lining rings, and annular wind guide belts. The lining ring material is a seamless steel pipe, which is lap-welded on the yoke punching sheets and concentric with the screw hole. The distance between the inner diameters of adjacent annular wind guide belts at the cold air inlet is large to reduce air volume loss, and the adjacent distance at the cold air outlet is close to the distance between the magnetic poles. The ventilation slots are installed between the stacked yoke punching sheets to form a second ventilation groove.

[0008] In the above-mentioned segmented laminated yoke with an air guide structure between yoke segments, the yoke key consists of a yoke convex key, a yoke sub-key, and a reinforcing key. The yoke convex key and the yoke sub-key are driven into the keyway connected to the rotor bracket by hot keying, and the installation tightness is ensured by adjusting the gasket. The key structures cooperate with each other to fix the position of the yoke key to prevent axial movement. The reinforcing key is a pair of inclined wedges, which are driven into the keyway not connected to the rotor bracket to tighten the yoke, and the excess part is cut off after tightening.

[0009] In the above-mentioned segmented laminated yoke with an inter-segment wind-guiding structure for the yoke, the brake ring is welded by a ring plate and a vertical plate. The ring plate is processed with a screw mounting hole at a position concentric with the screw hole of the yoke punching sheet, and is installed on the lower section of the yoke through the yoke tensioning screw, nut, and locking block. The installation method is detachable, which is convenient for maintenance and replacement. A lifting hole is processed near the center for easy installation. At the same time, chamfers are provided on both sides to prevent wear between the fixed rings during the operation of the unit. The centrifugal force of the unit operation can act on the lower yoke pressure plate through the vertical plate, and a threaded hole is processed on the inner diameter side of the vertical plate to facilitate the combination of other wind shielding devices.

[0010] In the above-mentioned segmented laminated yoke with an inter-segment wind guide structure of the yoke, the wind shield structure is welded by an annular wind shield and vertical ribs, installed in the gap between the upper end of the yoke and the rotor bracket, and welded to the wind shield of the rotor bracket to increase the air gap pressure here, while preventing the air at the end from flowing backwards here to form vortices, thereby improving ventilation efficiency.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. The yoke of the present invention adopts a segmented lamination form, which is divided into two sections, the upper and lower sections, which can effectively reduce eddy current losses and improve generator efficiency. At the same time, it improves the overall stability of the yoke, reduces the difficulties in the installation and transportation of the yoke, and facilitates maintenance and repair.

[0013] 2. The inter-segment part of the segmented laminated yoke of the present invention has an air-guiding structure, which has a blocking effect on the air volume flowing to the gap between segments, can balance the air volume flowing to each ventilation groove, optimize the ventilation path, reduce the air volume loss, improve the air flow efficiency, and enable the air to be blown to the magnetic poles, stator coils and other parts more evenly through each ventilation groove, thereby alleviating the uneven heat dissipation of some stator wire rods and improving the operating stability and service life of the generator.

[0014] 3. In the design of the inter-segment air guide structure of the present invention, taking into account the limitations of the installation space between segments, an opening is provided in the inter-segment air guide structure of the yoke. When installing the lower nut of the upper yoke, the installation tool can directly engage the nut close to the inner diameter through the opening, which can effectively reduce the difficulty of installing the nut, avoid redesigning and producing complex-shaped tools for engagement, and save production costs.

[0015] 4. In the present invention, a windshield structure is welded to the gap between the upper end of the yoke and the rotor bracket, and a threaded hole is opened on the vertical plate of the bottom brake ring to facilitate the fixing of other windshield structures. This design can further reduce the air volume loss, and can also avoid the reverse flow of air at the upper and lower ends to form vortices, thereby improving the ventilation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following is a brief introduction to the drawings required for the embodiments:

[0017] Figure 1 It is the overall structural layout diagram of the segmented laminated yoke with the wind guide structure between the yoke segments;

[0018] Figure 2 It is a top view schematic diagram of a segmented laminated yoke with an air guide structure between yoke segments;

[0019] Figure 3 It is a bottom view schematic diagram of a segmented laminated yoke with an air guide structure between yoke segments;

[0020] Figure 4 It is a cross-sectional schematic diagram of a segmented laminated magnetic yoke inter-segment air guide structure having an inter-segment air guide structure of the magnetic yoke;

[0021] Figure 5 It is a cross-sectional schematic diagram of the ventilation slots of a segmented laminated yoke with an air guide structure between yoke segments;

[0022] Figure 6 A schematic diagram of chamfering the brake ring of a segmented laminated yoke having an air guide structure between yoke segments.

[0023] Description of the component numbers in the figure:

[0024] 1-Yoke punching plate; 2-Upper yoke pressure plate; 3-Inter-segment wind guide structure; 4-Lower yoke pressure plate; 5-Ventilation slot; 6-Yoke tightening screw; 7-Nut; 8-Adjusting gasket; 9-Locking block; 10-Yoke key; 11-Key structure; 12-Brake ring; 13-Wind shield structure; 14-T tail slot; 15-Inter-pole small dove tail slot; 16-Key slot; 17-Screw hole; 18-Pole Keyway; 19- "L" type air guide belt; 20- inlet opening; 21- first ventilation groove; 22- support block; 23- lining ring; 24- annular air guide belt; 25- second ventilation groove; 26- yoke convex key; 27- yoke secondary key; 28- reinforcement key; 29- ring plate; 30- vertical plate; 31- screw hole mounting hole; 32- chamfer; 33- threaded hole; 34- annular wind shield plate; 35- vertical rib. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be understood that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only simplified descriptions for the convenience of describing the present invention, rather than indicating or implying that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0026] like Figure 1 As shown, a segmented laminated yoke with an inter-segment wind guide structure of a yoke is composed of a yoke punching sheet 1, an upper yoke pressing plate 2, an inter-segment wind guide structure 3, a lower yoke pressing plate 4, a ventilation slot sheet 5, a yoke tightening screw 6, a nut 7, an adjustment gasket 8, a locking block 9, a yoke key 10, a key structure 11, a brake ring 12, and a windshield structure 13. The yoke punching sheets 1 are staggered and stacked together with the upper yoke pressing plate 2 and the ventilation slot sheet 5 through the yoke tightening The screw rod 6 and nut 7 are fastened to form the upper section of the laminated yoke, the yoke punching sheet 1 is staggered and fastened with the inter-section wind guide structure 3, the lower yoke pressure plate 4, and the ventilation slot sheet 5 through the yoke tightening screw 6 and nut 7 to form the lower section of the yoke, the yoke key 10 is driven into the two sections of the yoke and fastened to the rotor bracket, the key structure 11 fixes the yoke key 10, and the brake ring 12 is tightened by the yoke tightening screw 6, nut 7, and locking block 9 to form a whole at the lower end of the yoke. The windshield structure 13 is located at the upper end of the yoke and welded to the windshield of the rotor bracket.

[0027] like Figure 2 , Figure 3As shown, the yoke punching sheet 1 is fan-shaped, and a T-tail groove 14 is processed at the outer diameter for connection with the pole T-tail. A small inter-pole dovetail groove 15 is processed between the T-tail grooves 14 to connect the inter-pole connection device to form a passage between each pole. A keyway 16 is processed at the center line of the T-tail groove on the inner diameter of the punching sheet, and a pole key is driven into the keyway to prevent the pole punching sheet from being offset during the operation of the unit and affecting the stability of the unit. Four rows of screw holes 17 are opened on the yoke punching sheet 1 for connecting and fixing each punching sheet.

[0028] The structures of the upper yoke pressing plate 2 and the lower yoke pressing plate 4 are similar to those of the yoke punching sheet 1, and their outer diameters are slightly smaller than those of the yoke punching sheet 1, and their inner diameters are slightly larger than those of the yoke punching sheet 1. The upper yoke pressing plate 2 is processed with a T-tail groove 14, a small dove-tail groove 15 between poles, a key groove 16 and a screw hole 17 at the same positions as the yoke punching sheet 1, while the lower yoke pressing plate 4 is not processed with the T-tail groove 14, but with a pole key groove 18 at the T-tail position of the yoke punching sheet for driving a pole key to achieve a tight connection between the pole and the yoke.

[0029] like Figure 4 As shown, the inter-segment air guide structure 3 is welded by the upper yoke pressure plate 2 and the "L"-shaped air guide belt 19. The "L"-shaped air guide belt 19 is symmetrically welded at the inner diameter to form an inlet opening 20. The inter-segment air guide structure 3 is installed at the upper end of the lower yoke, used as a pressure plate and fastened to the yoke punching sheet 1 together with the lower yoke pressure plate 4. Its installation position is between the segmented yoke segments, and has a large gap to form the first ventilation groove 21. After the installation is completed, a support block 22 is welded in the middle position to support the upper yoke. The inter-segment air guide structure can optimize the ventilation path of the rotor yoke, and the opening design of the air guide belt is conducive to the installation of the upper yoke.

[0030] like Figure 5 As shown, the ventilation slot sheet 5 is welded by the yoke punching sheet 1, the lining ring 23, and the annular air guide belt 24. The lining ring material is a seamless steel pipe, which is lap-welded on the yoke punching sheet and is concentric with the screw hole 17. The distance between the inner diameters of adjacent annular air guide belts at the cold air inlet is large to reduce air volume loss, and the adjacent distance at the cold air outlet is close to the distance between the magnetic poles. The ventilation slot sheet 5 is installed between the stacked yoke punching sheets 1 to form a plurality of second ventilation grooves 25.

[0031] The yoke key 10 is composed of a yoke convex key 26, a yoke sub-key 27, and a reinforcing key 28. The yoke convex key 26 and the yoke sub-key 27 are driven into the keyway 16 connected to the rotor bracket by hot punching, and the installation tightness is ensured by adjusting the gasket 8. The key structure 11 is used to fix the position of the yoke key to prevent axial movement. The reinforcing key 28 is a pair of inclined wedges, which are driven into the keyway 16 not connected to the rotor bracket to tighten the yoke, and the excess part is cut off after tightening.

[0032] The brake ring 12 is welded by a ring plate 29 and a vertical plate 30. The ring plate 29 is processed with a screw mounting hole 31 at a position concentric with the screw hole 17 of the yoke punching sheet. It is installed on the lower section of the yoke through the yoke tensioning screw, nut, and locking block. The installation method is detachable, which is convenient for maintenance and replacement. Chamfers 32 are provided on both sides to prevent wear between the fixed rings during the operation of the unit. The centrifugal force of the unit operation can act on the lower yoke pressure plate through the vertical plate. A threaded hole 33 is processed on the inner diameter side of the vertical plate 30 to facilitate the combination of other windshield devices.

[0033] The windshield structure 13 is welded by an annular windshield 34 and vertical ribs 35, is located in the gap between the upper end of the yoke and the rotor bracket, and is welded to the windshield of the rotor bracket to increase the air gap pressure here, while preventing the air at the end from flowing backwards here to form vortices, thereby improving ventilation efficiency.

[0034] Finally, the protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope and spirit of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A segmented laminated yoke with an air guide structure between yoke segments, characterized in that: The invention comprises a yoke punching sheet (1), an upper yoke pressing plate (2), an inter-segment air guide structure (3), a lower yoke pressing plate (4), a ventilation slot sheet (5), a yoke tightening screw (6), a nut (7), an adjustment gasket (8), a locking block (9), a yoke key (10), a key structure (11), a brake ring (12), and a windshield structure (13). The yoke punching sheets (1) are stacked in an interlaced manner and are fastened with the upper yoke pressing plate (2) and the ventilation slot sheet (5) through the yoke tightening screw (6) and the nut (7) to form an upper laminated yoke. The yoke punching sheets (1) are staggered and stacked together with the inter-segment wind guide structure (3), the lower yoke pressure plate (4), and the ventilation slot sheet (5) through the yoke tightening screw (6) and the nut (7) to form the lower yoke; the yoke key (10) is driven into the two sections of the yoke and is tightened to the rotor bracket, the key structure (11) fixes the yoke key (10), and the brake ring (12) is fixed to the lower end of the yoke through the yoke tightening screw (6), the nut (7), and the locking block (9) to form a whole; the windshield structure (13) is located at the upper end of the yoke and is welded to the windshield of the rotor bracket.

2. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The yoke punching sheet (1) is fan-shaped, with a T-tail groove (14) processed at the outer diameter, a small inter-polar dove-tail groove (15) processed between the T-tail grooves (14), a key groove (16) processed at the center line of the T-tail groove on the inner diameter of the punching sheet, and four rows of screw holes (17) are provided on the yoke punching sheet (1).

3. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The structures of the upper yoke pressing plate (2) and the lower yoke pressing plate (4) are similar to those of the yoke punching sheet (1), and their outer diameters are slightly smaller than those of the yoke punching sheet (1), and their inner diameters are slightly larger than those of the yoke punching sheet (1). The upper yoke pressing plate (2) is processed with a T-tail groove (14), an inter-pole small dove-tail groove (15), a key groove (16) and a screw hole (17) at the same positions as the yoke punching sheet (1), and the lower yoke pressing plate (4) is processed with a magnetic pole key groove (18) at the T-tail position of the yoke punching sheet.

4. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The inter-segment air guide structure (3) is formed by welding an upper yoke pressure plate (2) and an "L"-shaped air guide belt (19). The "L"-shaped air guide belt (19) is symmetrically welded at the inner diameter to form an inlet opening (20). The inter-segment air guide structure (3) is installed at the upper end of the lower yoke and together with the lower yoke pressure plate (4) fixes the yoke punching sheet (1). Its installation position is between the segmented yoke segments and has a large gap to form a first ventilation groove (21). After installation is completed, a support block (22) is welded at the middle position.

5. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The ventilation slot sheet (5) is welded by a yoke punching sheet (1), a lining ring (23), and an annular air guide belt (24); the lining ring (23) is concentric with the screw hole (17); and the ventilation slot sheet (5) is installed between the stacked yoke punching sheets (1) to form a plurality of second ventilation grooves (25).

6. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The yoke key (10) is composed of a yoke convex key (26), a yoke sub-key (27), and a reinforcing key (28). The yoke convex key (26) and the yoke sub-key (27) are driven into a keyway (16) connected to the rotor bracket by hot punching, and the installation tightness is ensured by adjusting the gasket (8). The key structure (11) fixes the position of the yoke key. The reinforcing key (28) is a pair of inclined wedges, which are driven into the keyway (16) not connected to the rotor bracket to tighten the yoke, and the excess part is cut off after tightening.

7. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The brake ring (12) is welded from a ring plate (29) and a vertical plate (30); the ring plate (29) is provided with a screw mounting hole (31) at a position concentric with the screw hole (17) of the yoke punching sheet, chamfers (32) are provided on both sides, and a threaded hole (33) is provided on the inner diameter side of the vertical plate (30).

8. The segmented laminated yoke with an inter-segment wind guide structure of the yoke according to claim 1, characterized in that: The windshield structure (13) is formed by welding an annular windshield (34) and vertical ribs (35), is located in the gap between the upper end of the magnetic yoke and the rotor bracket, and is welded to the windshield of the rotor bracket.

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