CN215184285U

CN215184285U - Sealed battery pack

Info

Publication number: CN215184285U
Application number: CN202121118057.3U
Authority: CN
Inventors: 殷威
Original assignee: Shanghai Baicheng Electric Equipment Manufacture Co Ltd
Current assignee: Shanghai Baicheng Electric Equipment Manufacture Co Ltd
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2021-12-14
Anticipated expiration: 2031-05-24

Abstract

The utility model belongs to the technical field of the battery, a sealed battery package is disclosed, including the upper cover and the lower cover that are used for storing the battery assembly of electric energy and splice each other, the battery assembly is arranged in the chamber that holds that forms behind upper cover and the lower cover amalgamation. The upper cover comprises an upper cover body and a first connecting portion, the opening of the upper cover body is annularly arranged on the first connecting portion and is arranged in a protruding mode, a first protrusion and a first annular groove are arranged on the first connecting portion, the lower cover comprises a lower cover body and a second connecting portion, the opening of the lower cover body is annularly arranged on the second connecting portion and is arranged in a protruding mode, and a second protrusion and a second annular groove are arranged on the second connecting portion. The first bulges are inserted into the second annular groove, the second bulges are inserted into the first annular groove, the sealant can fill the gap between the first bulges and the second annular groove, after the sealant is cured, the upper cover and the lower cover can be firmly spliced, and the waterproof performance is good.

Description

Sealed battery pack

Technical Field

The utility model relates to a battery technology field especially relates to a sealed battery package.

Background

Along with the popularization of electric scooters and electric bicycles, the waterproof requirement on the power storage unit, namely a lithium battery pack, is higher and higher, so that the power core of the whole bicycle or the whole bicycle is better protected.

In the existing lithium battery pack, a groove position is reserved on a lower cover, and then a sealing ring is arranged in the corresponding groove position. The upper cover and the lower cover are fixed and pressed through screws, the bone position of the upper cover presses the sealing ring in the groove position of the lower cover, the sealing effect is poor, only the waterproof requirements of water splashing or spraying and the like can be met, the waterproof grade can reach IPx4/5 at most, and complete waterproof cannot be achieved. Moreover, the size range of the applicable product is limited, and the battery pack is only applicable to small-sized battery packs. If the overall dimension of group battery is too big, because the stress of rubber seal's upper and lower lid of plastic material for a long time, easily take place the deformation in the operational environment of high temperature and high humidity, be difficult to guarantee the holistic waterproof nature of battery package, in case spray or soak in aqueous, water will permeate the battery package, cause the inefficacy and the destruction of battery package.

In addition, when the existing battery pack is manufactured, the rubber sealing ring needs to be opened. Different molds need to be opened according to different product shapes, and the cost is seriously increased. And rubber seal itself is yielding, needs the manual work to aim at the trench in order to realize the assembly, and intensity of labour is big, wastes time and energy, can't realize automated production, in case have neglected loading or assemble not in place, can directly lead to the waterproof function of battery package to become invalid.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a sealed battery package can realize waterproof completely, improves the security of battery package, and need not the die sinking, and the process is simple, reduction in production cost when improving production efficiency.

To achieve the purpose, the utility model adopts the following technical proposal:

a sealed battery pack, comprising:

a battery assembly for storing electrical energy;

the upper cover comprises an upper cover body and a first connecting part, the first connecting part is annularly arranged on the opening of the upper cover body and is outwards protruded, and a first protrusion and a first annular groove are arranged on the first connecting part;

the lower cover comprises a lower cover body and a second connecting portion, wherein the second connecting portion is annularly arranged at the opening of the lower cover body and is outwards convexly arranged, a second protrusion and a second annular groove are arranged on the second connecting portion, the first protrusion is inserted into the second annular groove, the second protrusion is inserted into the first annular groove, sealant is filled between the groove wall of the second annular groove and the first protrusion, so that the upper cover and the lower cover are connected in a sealing mode to form a containing cavity, and the battery assembly is arranged in the containing cavity.

As the utility model provides a preferred scheme of sealed battery package, first protruding with the adjacent setting of first annular to form first stair structure, the second protruding with the adjacent setting of second annular is with formation second stair structure, first stair structure with second stair structure block.

As the utility model provides a preferred scheme of sealed battery package, sealed glue is waterproof glue.

As the utility model provides a sealed battery package's preferred scheme still includes safety relief valve, safety relief valve is used for balancing hold the intracavity outside differential pressure.

As the utility model provides a sealed battery package's preferred scheme still includes first retaining member, the safety relief valve passes through first retaining member is fixed in the upper cover body.

As the utility model provides a preferred scheme of sealed battery package still includes two setting elements that the interval set up, every the setting element is all located including protruding the first board of upper cover body inner wall, two first board is all protruding to be equipped with the second board to one side each other, safety relief valve passes the lateral wall of upper cover body, and with first retaining member threaded connection, first retaining member presss from both sides and locates the second board with between the inner wall of upper cover body.

As the utility model provides a preferred scheme of sealed battery package, still seted up charge lead wire mouth and discharge lead wire mouth on the upper cover body, charge terminal's one end with the battery assembly electricity is connected, and the other end passes through charge lead wire mouth draws hold the chamber outside, discharge terminal's one end with the battery assembly electricity is connected, and the other end passes through discharge lead wire mouth draws hold the chamber outside.

As the utility model provides a sealed battery package's preferred scheme still includes installed part and second retaining member, charge the pin hole with the pin hole that discharges all set up in on the installed part, the hole of dodging has still been seted up on the upper cover body, the installed part runs through dodge the hole and pass through the second retaining member is fixed in on the upper cover body.

As the utility model provides a preferred scheme of sealed battery package, be provided with backstop portion on the installed part, backstop portion butt in the inner wall of upper cover body, the installed part stretches out the one end of upper cover body with second retaining member threaded connection.

As the utility model provides a sealed battery package's preferred scheme still includes a plurality of fasteners, be provided with a plurality of connecting holes along the circumference interval on the first connecting portion, be provided with a plurality of screw holes, a plurality of along the circumference interval on the second connecting portion the connecting hole is with a plurality of the screw hole one-to-one sets up, every the fastener all passes the connecting hole, and with corresponding the screw hole is connected.

The utility model has the advantages that:

the utility model provides a sealed battery package, including the upper cover and the lower cover that are used for storing the battery assembly of electric energy and splice each other, the battery assembly is arranged in the chamber that holds that forms behind upper cover and the lower cover amalgamation. The upper cover comprises an upper cover body and a first connecting portion, the opening of the upper cover body is annularly arranged on the first connecting portion and is arranged in a protruding mode, a first protrusion and a first annular groove are arranged on the first connecting portion, the lower cover comprises a lower cover body and a second connecting portion, the opening of the lower cover body is annularly arranged on the second connecting portion and is arranged in a protruding mode, and a second protrusion and a second annular groove are arranged on the second connecting portion. When the equipment battery package, at first put into the battery assembly of equipment in the inner chamber of lower cover body, later pack sealed glue to the second annular groove intussuseption of lower cover, aim at the second annular groove of lower cover and insert with the first arch of upper cover afterwards, the second arch of lower cover is inserted in the first annular groove of locating the upper cover simultaneously, compress upper cover and lower cover, so that sealed glue can fill the clearance between first arch and the second annular groove, treat sealed gluey solidification back, upper cover and lower cover can firmly be amalgamated. The utility model provides a sealed battery package is through setting up the arch and the annular of mutually supporting on upper cover and lower cover to use sealed glue to fill the clearance, can realize the complete sealing between battery package upper cover and the lower cover, effectively improve waterproof grade. The utility model provides a sealed battery package replaces traditional rubber seal through pouring sealed glue between upper cover and lower cover, because sealed glue has certain mobility, consequently can fill up the clearance between upper cover and the lower cover better, compare in prior art, need not to carry out die sinking manufacturing and manual assembly to rubber seal, save the cost, and can avoid upper cover and lower cover to receive rubber seal's stress and serious deformation for a long time, ensure that the holistic sealed waterproof nature of battery package is good.

Drawings

Fig. 1 is an exploded view of a sealed battery pack according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of a sealed battery pack according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of an upper cover according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a lower cover according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view of an upper cover according to an embodiment of the present invention;

fig. 6 is a partially enlarged view of a portion a in fig. 5;

fig. 7 is a partially enlarged view of a portion B in fig. 5.

In the figure:

1-a battery assembly; 2-covering the upper cover; 3-lower cover; 4-sealing glue; 5-an accommodating cavity; 8-a fastener;

21-upper cover body;

22-a first connection; 221-a first step structure; 222-a connection hole; 2211-first projection; 2212-first ring groove;

23-a positioning element; 231-a first plate; 232-a second plate;

31-lower cover body;

32-a second connection; 321-a second stepped structure; 322-a threaded hole; 3211-a second projection; 3212-second ring groove;

61-safety relief valve; 62-a first locking member;

71-a mount; 72-a second locking member; 73-a stop; 74-sealing ring;

100-a charging terminal; 200-discharge terminal.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used in the orientation or positional relationship shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

As shown in fig. 1 and 2, the present embodiment provides a sealed battery pack including a battery assembly 1 for storing electric energy, and an upper cover 2 and a lower cover 3 which are coupled to each other, wherein the battery assembly 1 is located in a receiving cavity 5 formed by coupling the upper cover 2 and the lower cover 3.

Referring to fig. 2, the upper cover 2 includes an upper cover body 21 and a first connecting portion 22, the first connecting portion 22 is annularly disposed at the opening of the upper cover body 21 and is outwardly protruded, a first protrusion 2211 and a first annular groove 2212 are disposed on the first connecting portion 22, the lower cover 3 includes a lower cover body 31 and a second connecting portion 32, the second connecting portion 32 is annularly disposed at the opening of the lower cover body 31 and is outwardly protruded, and a second protrusion 3211 and a second annular groove 3212 are disposed on the second connecting portion 32. When the battery pack is assembled, firstly, the assembled battery assembly 1 is placed in the inner cavity of the lower cover body 31, then the second annular groove 3212 of the lower cover 3 is filled with the sealant 4, then the first protrusion 2211 of the upper cover 2 is aligned with the second annular groove 3212 of the lower cover 3 and inserted, meanwhile, the second protrusion 3211 of the lower cover 3 is inserted into the first annular groove 2212 of the upper cover 2, the upper cover 2 and the lower cover 3 are pressed, so that the sealant 4 can be filled in the gap between the first protrusion 2211 and the second annular groove 3212, and after the sealant 4 is cured, the upper cover 2 and the lower cover 3 can be firmly spliced. The sealed battery package that this embodiment provided is through setting up the arch and the annular of mutually supporting on upper cover 2 and lower cover 3 to use sealed glue 4 to fill the clearance, can realize the complete sealing between battery package upper cover 2 and the lower cover 3, effectively improve waterproof grade. The utility model provides a sealed battery package replaces traditional rubber seal through pouring sealed glue 4 between upper cover 2 and lower cover 3, because sealed glue 4 has certain mobility, consequently can fill up the clearance between upper cover 2 and the lower cover 3 better, compare in prior art, need not to carry out die sinking manufacturing and manual assembly to rubber seal, save the cost, and can avoid upper cover 2 and lower cover 3 to receive rubber seal's stress and serious deformation for a long time, it is good to ensure the holistic sealed waterproof nature of battery package.

The battery assembly 1 comprises a battery core component and a control board component. In this embodiment, the control board assembly includes a BMS control board electrically connected to the electric core assembly.

With continued reference to fig. 2, optionally, in the present embodiment, the first protrusion 2211 and the first annular groove 2212 are disposed adjacent to form the first step structure 221. The second protrusion 3211 and the second annular groove 3212 are disposed adjacent to each other to form a second step structure 321, and the first step structure 221 and the second step structure 321 are engaged with each other. By providing the first step structure 221 and the second step structure 321, the contact area between the upper cover 2 and the lower cover 3 can be increased, and the stability after splicing can be improved. Moreover, the engagement of the first step structure 221 and the second step structure 321 can effectively prevent water from overflowing into the accommodating cavity 5, and avoid damaging the cell assembly and the control panel assembly in the accommodating cavity 5.

Preferably, the sealing glue 4 is a waterproof glue. The waterproof glue is filled between the first protrusion 2211 of the upper cover 2 and the second annular groove 3212 of the lower cover 3, and after curing, the upper cover 2 and the lower cover 3 can be firmly bonded, and a good waterproof effect is achieved. When the waterproof glue is filled in the second annular groove 3212, an automatic gluing machine can be used, manual operation is not needed, the production efficiency is improved, and the neglected loading risk can be reduced. Of course, in other embodiments, the sealing glue 4 may also be other flexible glue or other sealing materials, which is not limited herein.

Referring to fig. 3 and 5, in the present embodiment, a safety relief valve 61 is further connected to the upper cover body 21 for balancing the pressure difference between the inside and the outside of the accommodating chamber 5. The inside lithium cell that is of battery package can produce a small amount of gas when charging for it, can in time discharge the gas that holds in the chamber 5 through setting up safe relief valve 61, prevents that the gas accumulation in the battery package from leading to

upper cover

2 and 3 swell of lower cover and even breaking.

Alternatively, the safety relief valve 61 is fixed to the upper lid body 21 by a first locking member 62. Referring to fig. 3 and 6, in particular, safety relief valve 61 extends externally through cover body 21 and is connected to first locking member 62. The first locking piece 62 is stopped on the inner wall of the upper cover body 21 to prevent the safety relief valve 61 from shaking relative to the upper cover body 21, and the sealing performance of the safety relief valve 61 is ensured to be good.

Preferably, the first locking member 62 is a locking nut, and the safety relief valve 61 can be fixed on the upper cover body 21 by tightening the locking nut, so that the operation is simple and fast, and the assembly efficiency is high.

With continued reference to fig. 3 and 7, two positioning members 23 are spaced apart from each other in the accommodating chamber 5 to indicate the installation position of the safety relief valve 61 and further improve the stability after installation. Specifically, each positioning member 23 includes a first plate 231 protruding from the inner wall of the upper cover body 21, and a second plate 232 is protruding from one side of each of the two first plates 231 facing each other. Safety relief valve 61 passes the lateral wall of upper cover body 21 to with first retaining member 62 threaded connection, first retaining member 62 presss from both sides and locates between the inner wall of second board 232 and upper cover body 21, prevents effectively that safety relief valve 61 from rocking and leads to upper cover body 21 to appear the gap.

Optionally, the upper cover body 21 further has a charging lead port and a discharging lead port, one end of the charging terminal 100 is electrically connected to the battery assembly 1, and the other end is led out of the accommodating cavity 5 through the charging lead port. The charging terminal 100 is connected to a power source to charge the cell assembly. One end of the discharging terminal 200 is electrically connected to the battery assembly 1, and the other end is led out of the accommodating cavity 5 through a discharging lead port and connected to an external device or a host.

In this embodiment, safety relief valve 61, charging terminal 100 and discharge terminal 200 all have independent exit respectively to do water repellent one by one in exit department, thereby realize the thorough drainage of whole battery package, through experimenting that its waterproof grade can reach IP67 grade.

Optionally, referring to fig. 7, a mounting member 71 and a second locking member 72 are further disposed on the upper cover body 21, the charging lead port and the discharging lead port are both disposed on the mounting member 71, an avoiding hole is formed in the upper cover body 21, and the mounting member 71 penetrates through the avoiding hole and is fixed on the upper cover body 21 through the second locking member 72. Charging terminal 100 and discharge terminal 200 all pass mounting part 71 to it is fixed with mounting part 71, namely, charging terminal 100 and discharge terminal 200 assemble in advance on mounting part 71, only need afterwards with mounting part 71 pass on the upper cover body 21 dodge the hole and fixed through second retaining member 72 can, convenient operation is swift.

Further, referring to fig. 7, a stopping portion 73 is disposed on the mounting member 71, the stopping portion 73 abuts against the inner wall of the upper cover body 21, and one end of the mounting member 71 extending out of the upper cover body 21 is in threaded connection with the second locking member 72. The stopper 73 and the locking member work together to fix the mounting member 71 to the upper cover body 21, and the sealing property and the waterproof property after the fixation are good. The second locking member 72 is preferably a locking nut, and the gap between the mounting member 71 and the escape hole can be closed by tightening the locking nut.

Preferably, a sealing ring 74 is disposed between the stopper 73 and the inner wall of the upper cover body 21, so as to further improve the waterproof sealing performance at the charging terminal 100 and the discharging terminal 200. Of course, the installation member 71 may be waterproof by means of sealant filling.

Referring to fig. 1, optionally, the upper and

lower covers

2 and 3 are fixedly coupled by a plurality of fasteners 8. Specifically, referring to fig. 3, the first connection portion 22 is provided with a plurality of connection holes 222 at intervals in the circumferential direction. Referring to fig. 4, the second connecting portion 32 is provided with a plurality of threaded holes 322 at intervals in the circumferential direction. The plurality of connection holes 222 are provided in one-to-one correspondence with the plurality of screw holes 322. When the upper cover 2 is pressed, the connecting holes 222 are aligned with the threaded holes 322 of the lower cover 3 one by one, and each fastener 8 correspondingly passes through one connecting hole 222 and is connected with the threaded hole 322 right below. The fastener 8 is preferably a screw.

The utility model discloses an in other embodiments, upper cover 2 and lower cover 3 also can be fixed through ultrasonic wave butt fusion, perhaps buckle connected mode, not only are limited to the fix with screw.

The sealed battery pack provided by the embodiment has the following specific manufacturing steps:

s1, pre-assembling battery assembly 1: installing a BMS control board on the spot-welded electric core assembly, welding the BMS control board, and performing function test on a semi-finished product;

s2, integrally installing the battery assembly 1 with qualified function into the inner cavity of the lower cover 3 and fixing the battery assembly;

s3, using an automatic gluing machine to glue the waterproof glue in the second annular groove 3212 of the second connecting part 32 of the lower cover 3;

s4, a locking nut used for fixing the safety relief valve 61 is installed on the upper cover body 21 and clamped, and the installation piece 71, the charging terminal 100 and the discharging terminal 200 on the installation piece penetrate out of the avoidance hole in the side wall of the upper cover body 21;

s5, covering the upper cover 2 and the lower cover 3 which is glued;

s6, fixedly connecting the upper cover 2 and the lower cover 3 through screws (if the whole battery pack is pressed by a cover plate, locking screws are not needed);

s7, fixing the end of the mounting member 71 extending out of the upper cover body 21 by a lock nut to achieve waterproofing of the charging terminal 100 and the discharging terminal 200;

s8, carrying out an aging test on the battery pack, wherein the time is estimated to be four hours, and the curing of the waterproof adhesive can be realized in the process;

s9, testing the integral air tightness of the battery pack by using an air tightness tool at the safety relief valve 61;

and S10, installing the safety relief valve 61 and fixing the safety relief valve through a corresponding locking nut.

This embodiment is beaten waterproof glue through automatic and is replaced realizing through the sealing washer that the battery package is peripheral waterproof among the prior art, divides safety relief valve 61, charging terminal 100 and discharge terminal 200 into a plurality of branches simultaneously, carries out waterproof design one by one to realize the complete waterproof of package of battery package, whole package is waterproof can reach the IP67 grade.

It is obvious that the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, rearrangements and substitutions will now occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A sealed battery pack, comprising:

a battery assembly (1) for storing electrical energy;

the upper cover (2) comprises an upper cover body (21) and a first connecting part (22), the first connecting part (22) is annularly arranged at the opening of the upper cover body (21) and is outwards protruded, and a first protrusion (2211) and a first annular groove (2212) are arranged on the first connecting part (22);

the lower cover (3) comprises a lower cover body (31) and a second connecting part (32), the second connecting part (32) is annularly arranged on the opening of the lower cover body (31) and is outwards protruded, and a second protrusion (3211) and a second annular groove (3212) are arranged on the second connecting part (32)

The first protrusion (2211) is inserted into the second ring groove (3212), the second protrusion (3211) is inserted into the first ring groove (2212), a sealant (4) is filled between the groove wall of the second ring groove (3212) and the first protrusion (2211), so that the upper cover (2) and the lower cover (3) are connected in a sealing manner to form an accommodating cavity (5), and the battery assembly (1) is arranged in the accommodating cavity (5).

2. The sealed battery pack of claim 1, wherein the first protrusion (2211) and the first ring groove (2212) are disposed adjacent to form a first step structure (221), and the second protrusion (3211) and the second ring groove (3212) are disposed adjacent to form a second step structure (321), and the first step structure (221) and the second step structure (321) are engaged.

3. A sealed battery pack according to claim 1, wherein the sealant (4) is a waterproof glue.

4. The sealed battery pack according to claim 1, further comprising a safety relief valve (61), wherein the safety relief valve (61) is used for equalizing a pressure difference between the inside and the outside of the accommodating chamber (5).

5. The sealed battery pack according to claim 4, further comprising a first locking member (62), wherein the safety relief valve (61) is fixed to the upper cover body (21) by the first locking member (62).

6. The sealed battery pack according to claim 5, further comprising two positioning members (23) spaced apart from each other, wherein each positioning member (23) comprises a first plate (231) protruding from an inner wall of the upper cover body (21), a second plate (232) protruding from each side of the first plates (231) facing each other, the safety relief valve (61) penetrates through a side wall of the upper cover body (21) and is in threaded connection with the first locking member (62), and the first locking member (62) is sandwiched between the second plate (232) and the inner wall of the upper cover body (21).

7. The sealed battery pack according to claim 1, wherein the upper cover body (21) further has a charging lead port and a discharging lead port, one end of the charging terminal (100) is electrically connected to the battery assembly (1), the other end of the charging terminal is led out of the accommodating cavity (5) through the charging lead port, one end of the discharging terminal (200) is electrically connected to the battery assembly (1), and the other end of the discharging terminal is led out of the accommodating cavity (5) through the discharging lead port.

8. The sealed battery pack of claim 7, further comprising a mounting member (71) and a second locking member (72), wherein the charging lead port and the discharging lead port are both disposed on the mounting member (71), an avoiding hole is further formed in the upper cover body (21), and the mounting member (71) penetrates through the avoiding hole and is fixed on the upper cover body (21) through the second locking member (72).

9. The sealed battery pack according to claim 8, wherein a stopper (73) is provided on the mounting member (71), the stopper (73) abuts against the inner wall of the upper cover body (21), and one end of the mounting member (71) protruding from the upper cover body (21) is screwed to the second locking member (72).

10. The sealed battery pack according to any one of claims 1 to 9, further comprising a plurality of fastening members (8), wherein a plurality of connecting holes (222) are formed in the first connecting portion (22) at intervals in the circumferential direction, a plurality of threaded holes (322) are formed in the second connecting portion (32) at intervals in the circumferential direction, the plurality of connecting holes (222) and the plurality of threaded holes (322) are arranged in a one-to-one correspondence, and each fastening member (8) penetrates through the connecting hole (222) and is connected with the corresponding threaded hole (322).