CN117989064A - Double-direct-drive motor wind generating set - Google Patents

Abstract

The embodiment of the invention provides a double-direct-drive motor wind generating set, and relates to the field of wind power generation. The method aims to solve the bottleneck problem of the deep sea wind turbine generator system in the aspects of processing, manufacturing, hoisting, testing and the like. The motor assembly comprises two motor assemblies and an impeller assembly, each motor assembly comprises a tower barrel, a cabin and a generator, the cabin is fixed on the tower barrel, the generator comprises a rotor bracket and a stator bracket, and the stator bracket is fixed with the cabin; the impeller assembly comprises a hub and blades, the blades are connected to the hub, the hub is rotationally connected between the two motor assemblies, and the hub is fixed with rotor supports of the two generators. The power generated by the impeller assembly is distributed through the power generated by the two direct-drive generators, and a high-reliability direct-drive structure is reserved, so that the two direct-drive motors bear the power respectively, the structural size of corresponding parts is reduced, and bottlenecks in the aspects of processing, manufacturing, hoisting, testing and the like are not existed.

Description

Double-direct-drive motor wind generating set

Technical Field

The invention relates to the field of wind power generation, in particular to a double-direct-drive motor wind generating set.

Background

The deep-open sea floating wind power plant has extremely high cost of unit operation and construction due to the far distance from the shore; aiming at the site environment with high wind speed, more stable wind direction and wave flow direction in deep open sea, the ultra-high power unit is more suitable for a single point mooring type floating platform; the adopted single-point mooring type structure cancels a yaw system with higher fault rate of the unit, greatly improves the running reliability of the unit, and in the prior art, the large-power unit is developed, the unit part size is only designed in an amplified mode, longer blades, a larger gear box and higher power are designed, meanwhile, the direct-driven wind turbine generator is simple in structure and high in reliability, the offshore wind turbine generator has more advantages in application, and the failure risk of offshore operation and maintenance can be greatly reduced.

In the prior art, the development of the ultra-large unit is designed by a manufacturing system, and certain difficulty exists, firstly, the development of a high-power unit is faced in the aspects of blades, gear boxes, shafting and generators from the technical development level, the cost control constraint is adopted, firstly, the unit vibration problem is caused by the stiffness deformation matching problem faced, the ultra-long blade design causes lower torsional stiffness, the frequency in the flapping and shimmy directions of the blade is low, the resonance frequency of a main transmission chain of the unit is lower due to the design of high transmission ratio and large torque, meanwhile, the deformation control difficulty of the design of a sealing structure of the main transmission chain of the unit is higher in the design of a large-size structure, the linear speed of a rotor bracket of the generator is higher in the design of the generator, the requirements on a motor process are high, and the design difficulty of the unit is high under the mutual coupling effect of the generator, the main gear box and the frequency of the blade. On the other hand, higher requirements are put on manufacturing process equipment, processing difficulty, hoisting and transporting equipment and test experiment tables, such as heat treatment and machining equipment for gear rings of gear boxes, and model tests for core components such as blades, gear boxes, generators and the like, which exceed the investment of blade molds and factories, and larger experiment tables are required.

Disclosure of Invention

The invention aims to provide a double-direct-drive motor wind generating set, which can solve the problem that the deep sea wind generating set has bottlenecks in processing, manufacturing, hoisting, testing and the like.

Embodiments of the invention may be implemented as follows:

The embodiment of the invention provides a double-direct-drive motor wind generating set, which comprises motor assemblies and impeller assemblies, wherein the number of the motor assemblies is two, each motor assembly comprises a tower, a cabin and a generator, the cabin is fixed on the tower, the generator comprises a rotor bracket and a stator bracket, and the stator bracket is fixed with the cabin; the impeller assembly comprises a hub and blades, the blades are connected to the hub, the hub is rotationally connected between the two motor assemblies, and the hub is fixed with the rotor support of the two generators.

In addition, the double direct-drive motor wind generating set provided by the embodiment of the invention can also have the following additional technical characteristics:

Optionally, each of the motor assemblies further comprises a bearing; the bearing comprises an inner ring and an outer ring, wherein the inner ring is fixed with the stator support, and the outer ring is fixedly connected with the rotor support and the hub.

Optionally, each of the motor assemblies further comprises a brake disc, a brake ring and a brake; the brake disc is fixed with the outer ring, the brake ring is fixed with the inner ring, the brake is fixed on the brake ring, and the brake is used for locking or unlocking the brake disc.

Optionally, each of the motor assemblies further comprises a detent plate; the lock pin disc is fixed with the inner ring, a lock pin hole is formed in the lock pin disc, and the rotor bracket and the lock pin hole are fixed or separated through a pin.

Optionally, the hub is provided with an integrally formed motor end cover; the motor end cover is connected with one of the motor assemblies.

Optionally, the motor end cover, the brake disc, the outer ring and the rotor bracket are sequentially connected and fixed side by side.

Optionally, the hub is further provided with an integrally formed connecting flange, the connecting flange and the motor end cover are coaxially arranged, and the connecting flange is connected with another motor assembly.

Optionally, the connecting flange, the brake disc, the outer ring and the rotor bracket are sequentially connected and fixed side by side.

Optionally, the connecting flange is provided with a plurality of circumferential waist-shaped holes distributed at intervals along the circumferential direction; the length direction of each annular waist-shaped hole extends along the circumferential direction of the connecting flange so as to be capable of being circumferentially matched and fixed with the motor assembly.

Optionally, the double direct-drive motor wind generating set further comprises a plurality of compensation elastic cushion blocks; and each annular waist-shaped hole is internally fixed with a compensation elastic cushion block, and the compensation elastic cushion blocks are used for compensating the assembly residual space of the annular waist-shaped holes.

The double-direct-drive motor wind generating set provided by the embodiment of the invention has the beneficial effects that:

The double-direct-drive motor wind generating set comprises motor assemblies and impeller assemblies, wherein the number of the motor assemblies is two, each motor assembly comprises a tower barrel, a cabin and a generator, the cabin is fixed on the tower barrel, the generator comprises a rotor bracket and a stator bracket, and the stator bracket is fixed with the cabin; the impeller assembly comprises a hub and blades, the blades are connected to the hub, the hub is rotationally connected between the two motor assemblies, and the hub is fixed with rotor supports of the two generators.

The power generated by the impeller assembly is distributed through the power generated by the two direct-drive generators, and a high-reliability direct-drive structure is reserved, so that the two direct-drive motors bear the power respectively, the structural size of corresponding parts is reduced, and the problems of design, manufacturing process equipment, processing difficulty, hoisting and transporting equipment and a test experiment table existing in the application of the deep-open-sea single-point mooring type ultra-high-power wind generating set are solved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a wind turbine generator system with dual direct drive motors according to the present embodiment;

Fig. 2 is a schematic diagram of a wind turbine generator system with dual direct drive motors according to the present embodiment;

Fig. 3 is a schematic diagram of an internal structure of a wind turbine generator system with dual direct drive motors according to the present embodiment;

FIG. 4 is an enlarged view of a portion of FIG. 3A;

Fig. 5 is a schematic structural diagram of a left motor assembly, a nacelle and a tower of the dual direct drive motor wind turbine generator system provided in this embodiment;

FIG. 6 is an enlarged view of part of C in soil 4;

FIG. 7 is an enlarged view of a portion of B in FIG. 3;

Fig. 8 is a schematic structural diagram of a right motor assembly, a nacelle and a tower in the dual direct drive motor wind turbine generator system according to the present embodiment;

fig. 9 is a schematic structural diagram of a hub in a wind turbine generator system with dual direct drive motors according to the present embodiment;

fig. 10 is a partial enlarged view of D in fig. 9.

Icon: 10-a double direct-drive motor wind generating set; 100-motor assembly; 110-tower; 120-nacelle; 130-generator; 131-rotor support; 132-stator support; 133-stator winding frame; 200-impeller assembly; 210-a hub; 220-motor end caps; 230-connecting flanges; 231-annular waist-shaped holes; 232-compensating an elastic cushion block; 240-leaf; 300-inner ring; 310-outer ring; 400-brake disc; 410-a brake ring; 420-a brake; 500-a latch plate; 510-locking pin holes.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present invention, it should be noted that, if the terms "upper", "lower", "inner", "outer", and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, or the azimuth or the positional relationship in which the inventive product is conventionally put in use, it is merely for convenience of describing the present invention and simplifying the description, and it is not indicated or implied that the apparatus or element referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus it should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, if any, are used merely for distinguishing between descriptions and not for indicating or implying a relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

The following describes in detail the double direct drive motor wind power generation unit 10 provided in the present embodiment with reference to fig. 1 to 10.

Referring to fig. 1 and 2, an embodiment of the present invention provides a dual direct-drive motor wind generating set 10, which includes a motor assembly 100 and an impeller assembly 200, wherein the number of the motor assemblies 100 is two, each motor assembly 100 includes a tower 110, a nacelle 120 and a generator 130, the nacelle 120 is fixed on the tower 110, the generator 130 includes a rotor bracket 131 and a stator bracket 132, and the stator bracket 132 is fixed with the nacelle 120; the impeller assembly 200 includes a hub 210 and blades 240, the blades 240 are connected to the hub 210, the hub 210 is rotatably connected between the two motor assemblies 100, and the hub 210 is fixed to the rotor brackets 131 of the two generators 130.

The two towers 110 are used for being mounted on the ground, the two cabins 120 are respectively mounted on the two towers 110, and the hub 210 is rotatably connected between the two cabins 120. The wind force pushes the hub 210 and the blades 240 to rotate, so as to drive the rotor bracket 131 of the two motor assemblies 100 to rotate, and the mechanical energy is converted into electric energy through the two generators 130, so that power generation is realized. The nacelle 120 includes a nacelle 120 housing and a nacelle 120 casting secured within the nacelle 120 housing.

When the high-power unit design is carried out, the power generated by the impeller assembly 200 is distributed through the power generated by the two direct-drive generators 130, and a high-reliability direct-drive structure is reserved, so that the two direct-drive motors bear the power respectively, the structural dimensions of corresponding components are reduced, and particularly the bottlenecks in the aspects of processing, manufacturing, hoisting, testing and the like of the generators 130, the engine room 120 casting, the engine room 120 cover and the like are not existed any more, and the power sharing is carried out, so that the power-driven generator can be directly used with the existing mature products, and the manufacturing cost of a supply chain is greatly reduced. The problems of design, manufacturing process equipment, processing difficulty, hoisting and transporting equipment and a test experiment table existing in the application of the deep-open sea single-point mooring type ultra-high power wind driven generator 130 set are solved, and commercial operation of the floating type set with high cost performance is better realized.

The two motor assemblies 100 are respectively the left motor assembly 100 and the right motor assembly 100, and for convenience of explanation, the left motor assembly 100 and the right motor assembly 100 will be distinguished when the two motor assemblies 100 need to be distinguished.

Referring to fig. 3, 4 and 7, in the present embodiment, each motor assembly 100 further includes a bearing; the bearing includes an inner ring 300 and an outer ring 310, the inner ring 300 is fixed with the stator bracket 132, and the outer ring 310 is fixedly connected with the rotor bracket 131 and the hub 210.

Both motor assemblies 100 are coupled to the hub 210 by bearings. The bearing also includes bearing rollers that connect the inner ring 300 and the outer ring 310. The generator 130 further includes a stator winding frame 133, the stator bracket 132 is fixed to the inner ring 300, the stator winding frame 133 is fixed to the stator bracket 132, the rotor bracket 131 is located in the stator winding frame 133, and the rotor bracket 131 is fixed to the outer ring 310.

Referring to fig. 3, 4 and 7, in the present embodiment, each motor assembly 100 further includes a brake disc 400, a brake ring 410 and a brake 420; brake disc 400 is fixed to outer ring 310, brake ring 410 is fixed to inner ring 300, brake 420 is fixed to brake ring 410, and brake 420 is used to lock or unlock brake disc 400.

In the maintenance and repair state, it is necessary to secure the impeller assembly 200 in a locked state, and the brake ring 410 and the brake disc 400 are locked by the brake 420, so that the hub 210 is locked with the nacelle 120, and the hub 210 is prevented from rotating. Specifically, the brake 420 includes upper and lower calipers fixed to the brake ring 410, which respectively lock and unlock the brake disc 400.

Referring to fig. 3, 4, 5, 7 and 8, in this embodiment, each motor assembly 100 further includes a lock pin plate 500; the lock pin plate 500 is fixed to the inner ring 300, and the lock pin plate 500 is provided with a lock pin hole 510, and the rotor bracket 131 is fixed to or separated from the lock pin hole 510 by a pin.

The locking pin plate 500 is fixed with the rotor bracket 131 through pins, so that the rotor bracket 131 and the stator bracket 132 are fixed, and the impeller assembly 200 is prevented from rotating.

Referring to fig. 3 and 9, in the present embodiment, the hub 210 has an integrally formed motor end cap 220 thereon; motor end cap 220 is coupled to one of motor assemblies 100. In the installation process, the two motor assemblies 100 and the hub 210 are required to be coaxially arranged, and the connection positions are in one-to-one correspondence, so that in order to reduce the assembly difficulty, the motor end cover 220 of one of the generators 130 and the hub 210 are integrally formed, and the assembly error of the hub 210 and one of the motor assemblies 100 can be reduced, thereby reducing the assembly difficulty of the hub 210 and the other motor assembly 100.

Referring to fig. 3 and 7, in the present embodiment, motor end cover 220, brake disc 400, outer ring 310 and rotor bracket 131 are sequentially connected and fixed side by side. Brake ring 410 is located inside brake disc 400, and brake ring 410 is fixed with inner ring 300, and the assembly is compact, reducing the assembly space.

Referring to fig. 3 and 9, in this embodiment, the hub 210 further has an integrally formed connection flange 230, where the connection flange 230 is coaxially disposed with the motor end cover 220, and the connection flange 230 is connected with another motor assembly 100. One motor assembly 100 is assembled with the motor end cap 220 and then the other motor assembly 100 is connected with the connecting flange 230.

Referring to fig. 3 and 4, in the present embodiment, the connection flange 230, the brake disc 400, the outer ring 310, and the rotor bracket 131 are sequentially connected and fixed side by side. Brake ring 410 is positioned inside brake disc 400, brake ring 410 is fixed to inner ring 300, and stator support 132 is fixed to inner ring 300.

Referring to fig. 9 and 10, in the present embodiment, the connecting flange 230 is provided with a plurality of circumferential waist-shaped holes 231 distributed at intervals along the circumferential direction; the length direction of each of the circumferential waist-shaped holes 231 extends along the circumferential direction of the connection flange 230 so as to be circumferentially fitted and fixed with the motor assembly 100.

After the motor end cover 220 of the hub 210 is assembled with one motor assembly 100, the other motor assembly 100 needs to be assembled with the connecting flange 230, and the circumferential waist-shaped holes 231 are arranged, so that circumferential position adjustment correspondence can be realized, and the brake discs 400 are in one-to-one correspondence with the connecting holes of the connecting flange 230.

Referring to fig. 4 and 6, in the present embodiment, the dual direct-drive motor wind generating set 10 further includes a plurality of compensating elastic pads 232; a compensating elastic cushion block 232 is fixed in each annular waist-shaped hole 231, and the compensating elastic cushion block 232 is used for compensating the assembly residual space of the annular waist-shaped holes 231.

The problems of deviation displacement and bolt dislocation caused by misalignment are fully absorbed, and the problem of double-motor assembly is finally solved through a rigid-flexible design assembly scheme.

According to the dual direct-drive motor wind generating set 10 provided in the present embodiment, the working principle of the dual direct-drive motor wind generating set 10 includes:

The hub 210 serves as a mechanical component for connecting the left motor assembly 100 and the right motor assembly 100, and the torque generated by aerodynamic force of the blades 240 is respectively transmitted to the brake disc 400, the outer ring 310 and the rotor bracket 131 in the left motor assembly 100 through the connecting flange 230 on the left side of the hub 210, and directly transmitted to the rotor bracket 131 through the motor end cover 220 on the right side of the hub 210, so that induced currents are generated by the stator winding frame 133 in the left motor assembly 100 and the windings on the stator winding frame 133 in the right motor assembly 100, and power generation is realized. The aerodynamic forces of the blades 240 generate torque and bending moments, so that the left motor assembly 100 and the right motor assembly 100 are required to be transmitted to the bottom of the tower 110 to be offset, the bending moments are respectively transmitted to a brake disc 400, an outer ring 310, bearing rollers, an inner ring 300, a stator bracket 132 and a cabin 120 casting in the left motor assembly 100 through a connecting flange 230 on the left side of the hub 210, and transmitted to the tower 110, and a motor end cover 220 on the right side of the hub 210 is transmitted to the brake disc 400, the outer ring 310, the bearing rollers, the inner ring 300, the stator bracket 132 and the cabin 120 casting.

In addition to normal operation and power generation, a maintenance and repair state needs to be considered, in which the impeller assembly 200 needs to be guaranteed to have a completely locked state, and the impeller assembly is mainly supported by a brake 420 in the left motor assembly 100 and a locking pin hole 510 formed in an end portion of the locking pin disc 500, and a brake 420 in the right motor assembly 100 and a locking pin hole 510 formed in an end portion of the locking pin disc 500, wherein the locking pin disc 500 is fixed on the motor end cover 220 through bolts, the brake 420 is fixed on the brake ring 410, the brake disc 400 is locked through upper and lower calipers, and the locking pin holes 510 formed in the rotor bracket 131 and the locking pin disc 500 are locked mechanically, and a maintenance channel is provided in the main bearing hub 210 of the generator 130 of the nacelle 120, so that the generator has high maintainability and high accessibility.

Since the middle impeller assembly 200 is required to fix the left and right side generator assemblies by bolts at both ends, and the left and right side generator assemblies are required to be positioned to the two towers 110, there is unavoidable assembly constraint problem, so that the motor end cover 220 on the right side of the hub 210 is integrally formed with the hub 210, the rotor bracket 131 of the right side motor assembly 100 is connected to the motor end cover 220 by bolts, so that the left side motor assembly 100 is integrally assembled with the hub 210, on the other hand, from the assembly point of view, the left side motor assembly 100 is integrally assembled with the hub 210 as a whole to the tower 110, the right side motor assembly 100 is separately assembled and positioned to the tower 110, then the connecting flange 230 on the left side of the hub 210 is connected with the outer ring 310, the bolt connection at this position causes over constraint and interference problem due to assembly and manufacturing errors, firstly, the annular waist-shaped hole 231 is provided with the compensating elastic cushion block 232, the offset displacement and the bolt dislocation caused by the sufficient absorption of the misalignment are fully absorbed on the connecting flange 230 on the left side of the hub 210, and the final double design scheme of the assembly is adopted by a soft motor assembly.

The wind generating set 10 with double direct-drive motors provided by the embodiment has at least the following advantages:

The power generated by the impeller assembly 200 is distributed through the front and rear generators 130, so that the two generators 130 bear the power respectively, the structural dimensions of corresponding components, such as the blades 240, the gear box, the generators 130 and the like, are reduced, bottlenecks in processing, manufacturing, hoisting, testing and the like are not existed, and the power sharing can be directly used with the existing mature products, so that the manufacturing cost of a supply chain is greatly reduced.

The generator 130 adopts a single-bearing bolt connection structure, the assembly is simple, the reliability is high, and meanwhile, the maintenance channel formed by the inner cavities of the engine room 120, the generator 130, the bearing and the hub 210 is used for enabling the unit to have high maintainability and high accessibility.

The motor end cover 220 of the hub 210 is shared with the generator 130, and the rotor bracket 131 is coupled to the motor end cover 220 of the hub 210 by bolts, so that the left motor assembly 100 is integrally assembled with the hub 210.

The connecting flange 230 of the hub 210 is provided with a circumferential waist-shaped hole 231, the circumferential waist-shaped hole 231 is provided with a compensation elastic cushion block 232, the problems of deviation displacement and bolt dislocation caused by misalignment are fully absorbed, and the problem of double-motor assembly is finally solved through a rigid-flexible design assembly scheme.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A double direct drive motor wind generating set, comprising:

-motor assemblies (100), the number of motor assemblies (100) being two, each motor assembly (100) comprising a tower (110), a nacelle (120) and a generator (130), the nacelle (120) being fixed on the tower (110), the generator (130) comprising a rotor support (131) and a stator support (132), the stator support (132) being fixed with the nacelle (120);

And an impeller assembly (200), the impeller assembly (200) comprises a hub (210) and blades (240), the blades (240) are connected to the hub (210), the hub (210) is rotatably connected between the two motor assemblies (100), and the hub (210) is fixed with the rotor brackets (131) of the two generators (130).

2. The double direct drive motor wind generating set of claim 1, wherein:

Each of the motor assemblies (100) further includes a bearing; the bearing comprises an inner ring (300) and an outer ring (310), wherein the inner ring (300) is fixed with the stator bracket (132), and the outer ring (310) is fixedly connected with the rotor bracket (131) and the hub (210).

3. The double direct drive motor wind generating set of claim 2, wherein:

Each of the motor assemblies (100) further includes a brake disc (400), a brake ring (410), and a brake (420); the brake disc (400) is fixed with the outer ring (310), the brake ring (410) is fixed with the inner ring (300), the brake (420) is fixed on the brake ring (410), and the brake (420) is used for locking or unlocking the brake disc (400).

4. A dual direct drive electric motor wind generating set as defined in claim 3, wherein:

Each of the motor assemblies (100) further includes a detent plate (500); the lock pin disc (500) is fixed with the inner ring (300), a lock pin hole (510) is formed in the lock pin disc (500), and the rotor bracket (131) is fixed with or separated from the lock pin hole (510) through a pin.

5. The double direct drive motor wind power generator set according to claim 3 or 4, wherein:

The hub (210) is provided with an integrally formed motor end cover (220); the motor end cap (220) is connected to one of the motor assemblies (100).

6. The double direct drive motor wind generating set according to claim 5, wherein:

the motor end cover (220), the brake disc (400), the outer ring (310) and the rotor bracket (131) are sequentially connected and fixed side by side.

7. The double direct drive motor wind generating set according to claim 5, wherein:

The hub (210) is further provided with an integrally formed connecting flange (230), the connecting flange (230) and the motor end cover (220) are coaxially arranged, and the connecting flange (230) is connected with the other motor assembly (100).

8. The dual direct drive motor wind generating set of claim 7, wherein:

The connecting flange (230), the brake disc (400), the outer ring (310) and the rotor bracket (131) are sequentially connected and fixed side by side.

9. The dual direct drive motor wind generating set of claim 7, wherein:

The connecting flange (230) is provided with a plurality of annular waist-shaped holes (231) which are distributed at intervals along the circumferential direction; the length direction of each annular waist-shaped hole (231) extends along the circumferential direction of the connecting flange (230) so as to be capable of being circumferentially matched and fixed with the motor assembly (100).

10. The dual direct drive motor wind generating set of claim 9, wherein:

The double-direct-drive motor wind generating set further comprises a plurality of compensation elastic cushion blocks (232); and each annular waist-shaped hole (231) is internally fixed with a compensation elastic cushion block (232), and the compensation elastic cushion blocks (232) are used for compensating the assembly residual space of the annular waist-shaped holes (231).