CN113328114B

CN113328114B - Metal bipolar plate of inspection wiring structure for fuel cell

Info

Publication number: CN113328114B
Application number: CN202110883470.7A
Authority: CN
Inventors: 左涛; 吴剑; 陈朝阳
Original assignee: Aideman Hydrogen Energy Equipment Co ltd
Current assignee: Aideman Hydrogen Energy Equipment Co ltd
Priority date: 2021-08-03
Filing date: 2021-08-03
Publication date: 2021-10-26
Anticipated expiration: 2041-08-03
Also published as: CN113328114A

Abstract

The invention relates to the technical field of fuel cells, in particular to a metal bipolar plate of an inspection wiring structure for a fuel cell, which comprises an upper end plate, a bipolar plate, a lower end plate and a first connecting screw rod, the bipolar plate comprises a plate body, wherein the outer surface of the plate body is provided with a fuel hole, a liquid discharge hole and an oxygen hole in a penetrating way, the outer surface of the plate body is provided with a diversion trench and a groove, the groove surrounds the periphery of the diversion trench, X-axis runners are uniformly distributed in the diversion trench, y-axis runners are arranged at two ends of the X-axis runner, the Y-axis runners are designed in a wave-shaped structure, vent grooves are formed in the inner wall of the fuel hole, the fuel hole is communicated with the diversion trench through the vent groove, the side surface of the plate body is provided with an inspection line positioning groove, the outer surface of the lower end plate is inserted with a wiring limiting assembly, and the bottom end of the wiring limiting assembly is movably connected with a pressing sheet. The invention has a transverse flow guide channel, fully guides fuel, adopts a tablet wiring mode, is convenient to disassemble and assemble, and is beneficial to later maintenance.

Description

Metal bipolar plate of inspection wiring structure for fuel cell

Technical Field

The invention relates to the technical field of fuel cells, in particular to a metal bipolar plate of an inspection wiring structure for a fuel cell.

Background

The fuel cell is a novel cell capable of generating electricity, wherein a cell stack is equipment for generating electricity, and a bipolar plate in the cell stack is a core part and is provided with a fuel and an oxidant which are separated to prevent gas from permeating; the battery needs to monitor the working voltage of the monocell during operation under the action of collecting and conducting current, so that the inspection main board is connected with the bipolar plate for detecting the voltage of the battery.

The Chinese patent with publication number CN112259774A discloses a device for independently inspecting and replacing a bipolar plate and a membrane electrode assembly clamped by the bipolar plate in a stack and a use method thereof, belonging to the field of electrochemistry. The top of the bipolar plate in the pile is provided with a handle, the bottoms of the two side surfaces of the bipolar plate in the pile are respectively provided with a stud, the stud is provided with a through hole and a hole, the end plates at the two sides of the pile are provided with slideways, the slideways are provided with slide blocks, a swing arm is arranged between every two adjacent slide blocks, and the stud is positioned under the rectangular frame structure; the through hole bolt penetrates through the through hole to be fixedly connected with the bipolar plate which is not overhauled; the hole bolt is screwed into the hole through the swing arm, the swing arm and the stud on the bipolar plate which is clamped with the membrane electrode to be tested are fixedly connected through the hole bolt, and the bipolar plate which is clamped with the membrane electrode to be tested is taken out by pushing the stud in the direction of the handle. The invention aims to solve the problem that membrane assemblies needing to be checked or replaced cannot be taken out under the condition of not disassembling the stack at present, and the like.

However, the inspection structure has some problems, one of which is that the top of the bipolar plate in the stack is provided with a handle, the bottoms of the two side surfaces of the bipolar plate in the stack are provided with studs, the studs are provided with through holes and holes, the bipolar plate is a very thin part, and the handle and the studs are arranged on the bipolar plate, so that the volume of the bipolar plate is greatly increased, and the stack is huge after combination.

Secondly, through be equipped with the slide on pile both sides end plate, be equipped with the slider on the slide, be equipped with the swing arm between two adjacent sliders, the peg is located the rectangular frame structure under, and the peg on the bipolar plate of the membrane electrode that awaits measuring has been pressed from both sides to clearing hole bolt fixed connection swing arm and package, through promoting the peg to the handle direction and take out the package and pressed from both sides the bipolar plate of the membrane electrode that awaits measuring, at first the battery is piled at the during operation, every bipolar plate all need be patrolled and examined at any time, patrol and examine through the mode of taking out, the troublesome poeration, secondly, the battery piles the inner part needs high sealed, bipolar plate is after the assembly, the centre gripping is very tight, just can satisfy permanent gas-liquid seal, patrol and examine through dismouting bipolar plate at any time, can't guarantee normal leakproofness, and complex operation, the out-of work also can't the circular telegram of bipolar plate, be difficult to drop into volume production and use.

The current battery pile inspection mode mainly still fixes the circuit board of patrolling and examining on the battery pile, will patrol and examine the circuit board and be connected through winding displacement and bipolar plate electricity, and the winding displacement is connected through the welded mode with bipolar plate mainly, owing to patrol and examine the winding displacement and only be connected with monolithic bipolar plate, bipolar plate piles up compactly, and bipolar plate is very thin again, consequently, the welding degree of difficulty is big, and the welding mode dismouting is troublesome, is unfavorable for the later stage maintenance.

Therefore, it is desirable to design a metal bipolar plate of an inspection wiring structure for a fuel cell to solve the above problems.

Disclosure of Invention

The invention aims to provide a metal bipolar plate of an inspection wiring structure for a fuel cell, which aims to solve the problems that the inspection flat cable and the bipolar plate in the background technology are difficult to connect and are not beneficial to later maintenance.

In order to achieve the purpose, the invention provides the following technical scheme: a metal bipolar plate of an inspection wiring structure for a fuel cell comprises an upper end plate, a bipolar plate, a lower end plate and a first connecting screw rod, wherein the bipolar plate is stacked up and down, the upper end plate and the lower end plate are respectively arranged at the upper end and the lower end of the bipolar plate, the side surfaces of the upper end plate and the lower end plate are fixed through the first connecting screw rod, the bipolar plate comprises a plate body, the outer surface of the plate body is penetrated and provided with a fuel hole, a liquid discharge hole and an oxygen hole, the outer surface of the plate body is provided with a diversion trench and a groove, the groove surrounds the periphery of the diversion trench, X-axis runners are uniformly distributed in the diversion trench, two ends of each X-axis runner are provided with a Y-axis runner, each Y-axis runner is in a wave-shaped structural design, the inner wall of the fuel hole is provided with a vent trench, the fuel hole is communicated with the diversion trench through the vent trench, and the side surface of the plate body is provided with an inspection line positioning groove, the outer surface of the lower end plate is inserted with a wiring limiting assembly, and the bottom end of the wiring limiting assembly is movably connected with a pressing sheet.

Preferably, the fuel holes and the oxygen holes are distributed on two sides of the liquid discharge hole, the number of the fuel holes, the number of the liquid discharge hole and the number of the oxygen holes are two, the two fuel holes, the two liquid discharge holes and the two oxygen holes are distributed on the left end and the right end of the X-axis runner, the two fuel holes and the two oxygen holes are distributed diagonally, the fuel holes, the two liquid discharge holes and the two oxygen holes are circular, the inner diameters of the fuel holes and the oxygen holes are equal, and the inner diameter of the fuel holes is one half of the inner diameter of the liquid discharge holes.

Preferably, the surface of the Y-axis flow channel is uniformly provided with valley grooves, and the width of the valley grooves increases progressively and uniformly from the side close to the vent groove to the side far away from the vent groove.

Preferably, the bottom of patrolling and examining the line constant head tank is the arc, the left side slope of patrolling and examining the line constant head tank is steeper than the right side slope, and patrols and examines that line constant head tank right side is domatic to be longer than the left side domatic.

Preferably, the outer surface of the lower end plate is fixed with a second connecting screw, the outer surface of the second connecting screw is sleeved with a protective cover, heat dissipation holes are uniformly formed in the two sides of the protective cover in a penetrating mode, and the two ends of the right side of the protective cover are respectively connected and fixed with the bipolar plate and the lower end plate through screws.

Preferably, the wiring limiting assembly comprises a fixed seat, the fixed seat is L-shaped, the fixed seat is made of metal materials, the materials of the fixed seat are the same as those of the plate body, the thickness of the fixed seat is equal to that of the upper end plate and the lower end plate, the fixed seat is fixedly connected with the bipolar plate and the lower end plate through first connecting screw rods, a sliding groove is formed in the outer surface of the fixed seat, the sliding groove is inclined towards the direction of the bipolar plate, the pressing plate is connected with the sliding groove in a sliding mode, a reed is arranged inside the sliding groove, one end of the reed is fixedly connected with the inner wall of the sliding groove, and the other end of the reed is arc-shaped.

Preferably, logical groove has been seted up to the surface of fixing base, lead to groove and spout intercommunication, the inside that leads to the groove is provided with end cap, spring and spacing stake, the one end of spacing stake is inserted with the inner wall of spout and is closed, and the other end and the spring of spacing stake are contradicted, the other end and the end cap of spring are contradicted, and just spacing stake passes through the screw thread and leads to the groove to be connected fixedly.

Compared with the prior art, the invention has the beneficial effects that: this fuel cell is with patrolling and examining metal bipolar plate of wiring structure has horizontal water conservancy diversion runner, and abundant water conservancy diversion fuel adopts the preforming formula mode of connection, makes things convenient for the dismouting, does benefit to later stage maintenance.

(1) The Y-axis flow channel is fixed at the left end and the right end of the X-axis flow channel, the Y-axis flow channel is in a wave-shaped structure design, the valley width of the Y-axis flow channel is gradually increased from the side close to the air groove to the side far away from the air groove, the air pressure is maximum due to the fact that the side close to the air groove is the air outlet, along with outward diffusion, the air pressure is reduced, the flow speed is slowed down, the air guide channel at the position far away from the air groove is larger by changing the valley width on the right side of the Y-axis flow channel, the problem of air pressure reduction is solved, fuel is uniformly distributed in the flow guide groove to sufficiently separate electrons, and the power generation efficiency is improved.

(2) Through having seted up in the side of plate body and patrolling and examining the line constant head tank, do benefit to and patrol and examine the end of a thread location to all install the spacing subassembly of wiring on bipolar plate and lower end plate, swing joint has the preforming on the spacing subassembly of wiring, and the cooperation is patrolled and examined line constant head tank location and is patrolled and examined the end of a thread after well, promotes the preforming to the bipolar plate direction again, makes the preforming push down and patrols and examines the end of a thread, can accomplish to patrol and examine line and bipolar plate be connected, avoids welding loaded down with trivial details, and the later stage is unfavorable for demolising the problem of maintaining.

Drawings

FIG. 1 is a schematic view of the entire structure of the present invention;

FIG. 2 is a partial schematic view of the structure of the present invention;

FIG. 3 is a schematic view of the bipolar plate of FIG. 1 according to the present invention;

FIG. 4 is a schematic view of the wiring limiting assembly of FIG. 1 according to the present invention;

FIG. 5 is a schematic cross-sectional view of the structure at A-A in FIG. 4 according to the present invention;

FIG. 6 is an enlarged view of the structure at B in FIG. 3 according to the present invention.

In the figure: 1. an upper end plate; 2. a bipolar plate; 21. a plate body; 22. a fuel hole; 23. a drain hole; 24. an oxygen hole; 25. a diversion trench; 26. an X-axis flow channel; 27. a Y-axis flow channel; 28. a groove; 29. a routing inspection line positioning groove; 210. a vent channel; 3. a lower end plate; 4. a first connecting screw; 5. a second connecting screw; 6. a protective cover; 7. a wiring limiting component; 71. a fixed seat; 72. a chute; 73. a reed; 74. a plug; 75. a through groove; 76. a spring; 77. limiting piles; 8. and (6) tabletting.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 6, a metal bipolar plate of an inspection wiring structure for a fuel cell according to an embodiment of the present invention includes an upper end plate 1, a bipolar plate 2, a lower end plate 3, and first connecting screws 4, the bipolar plate 2 is stacked up and down, the upper end plate 1 and the lower end plate 3 are respectively disposed at the upper end and the lower end of the bipolar plate 2, the side surfaces of the upper end plate 1 and the lower end plate 3 are fixed by the first connecting screws 4, the bipolar plate 2 includes a plate body 21, a fuel hole 22, a liquid discharge hole 23, and an oxygen hole 24 are formed on the outer surface of the plate body 21, a flow guide groove 25 and a groove 28 are formed on the outer surface of the plate body 21, and the groove 28 surrounds the flow guide groove 25, as shown in fig. 3, the groove 28 is disposed around the fuel hole 22, the liquid discharge hole 23, and the oxygen hole 24, and a sealing ring is engaged with the groove 28 to ensure the sealing performance between the bipolar plates 2.

Inside evenly distributed of guiding gutter 25 has X axial flow way 26, the both ends of X axial flow way 26 all are provided with Y axial flow way 27, Y axial flow way 27 is the wave structural design, air duct 210 has been seted up to fuel hole 22's inner wall, and fuel hole 22 passes through air duct 210 and guiding gutter 25 intercommunication, the side of plate body 21 has been seted up and has been patrolled and examined line constant head tank 29, the surface of lower terminal plate 3 is inserted and has been closed the spacing subassembly 7 of wiring, the bottom swing joint of the spacing subassembly 7 of wiring has preforming 8.

Further, as shown in fig. 1, the fuel holes 22 and the oxygen holes 24 are distributed on two sides of the liquid discharge hole 23, the number of the fuel holes 22, the liquid discharge hole 23 and the oxygen holes 24 is two, the two fuel holes 22, the liquid discharge hole 23 and the oxygen holes 24 are distributed on the left end and the right end of the X-axis flow channel 26, the two fuel holes 22 and the two oxygen holes 24 are distributed diagonally, the fuel holes 22, the liquid discharge hole 23 and the oxygen holes 24 are circular, and can also be designed into a square shape or any regular geometric shape, the inner diameter of the fuel hole 22 is one half of the inner diameter of the liquid discharge hole 23, and the liquid discharge hole 23 with a large inner diameter can fully guarantee water discharge and avoid water accumulation.

Further, as shown in fig. 1 and 6, valley grooves are uniformly formed in the surface of the Y-axis flow channel 27, the width of the valley grooves increases progressively and uniformly from the side close to the vent groove 210 to the side far from the vent groove 210, that is, the width of the valley grooves on the surface of the Y-axis flow channel 27 gradually increases, since the side close to the vent groove 210 is an air outlet, the air pressure is the largest, and the air pressure decreases along with outward diffusion, which results in a slow flow rate, and the air guide channel at the position far from the vent groove 210 is larger by changing the valley width on the right side of the Y-axis flow channel 27, which makes up the problem of air pressure decrease, so that the fuel is uniformly distributed in the guide groove 25 to separate electrons sufficiently, thereby improving the power generation efficiency.

Further, as shown in fig. 6, the bottom of patrolling and examining line constant head tank 29 is the arc, and the left side slope of patrolling and examining line constant head tank 29 steeps in the right side slope, and patrols and examines line constant head tank 29 right side slope domatic being longer than the left side domatic, makes and patrols and examines the connector lug and press and to patrol and examine line constant head tank 29 in the back and inwards buckle, increase and patrol and examine the area of contact of line constant head tank 29, more do benefit to electrically conductive, the part that upwarps can fully contact with preforming 8, make the tighter that preforming 8 pressed.

Further, as shown in fig. 1, a second connecting screw 5 is fixed on the outer surface of the lower end plate 3, a protective cover 6 is sleeved on the outer surface of the second connecting screw 5, heat dissipation holes are uniformly formed in two sides of the protective cover 6, heat dissipation of the inspection circuit board is facilitated, two ends of the right side of the protective cover 6 are respectively connected and fixed with the bipolar plate 2 and the lower end plate 3 through screws, and the protective cover 6 plays a protective role in the inspection circuit board.

Further, as shown in fig. 2, 4 and 5, the wiring limiting assembly 7 includes a fixing seat 71, the fixing seat 71 is L-shaped, the fixing seat 71 is made of metal, the material of the fixing seat 71 is the same as that of the plate body 21, the thickness of the fixing seat 71 is equal to that of the upper end plate 1 and the lower end plate 3, after the fixing seat 71 is mounted on the upper end plate 1 and the lower end plate 3, the upper and lower sides are flush with the bipolar plate 2 and the lower end plate 3, the fixing seat 71 is respectively connected and fixed with the bipolar plate 2 and the lower end plate 3 through a first connecting screw 4, a sliding groove 72 is formed in the outer surface of the fixing seat 71, the sliding groove 72 is inclined toward the bipolar plate 2, the pressing plate 8 slides leftward to abut against the side surface of the bipolar plate 2, the pressing plate 8 is slidably connected with the sliding groove 72, a spring 73 is disposed inside the sliding groove 72, one end of the spring 73 is connected and fixed to the inner wall of the sliding groove 72, and the other end of the spring 73 is arc, when the pressing sheet 8 is pushed to the leftmost side, the spring plate 73 can abut against the surface of the pressing sheet 8, so that the pressing sheet 8 tightly presses the routing inspection flat cable.

Further, as shown in fig. 4-5, a through groove 75 is formed in the outer surface of the fixing seat 71, the through groove 75 is communicated with the sliding groove 72, a plug 74, a spring 76 and a limiting pile 77 are arranged inside the through groove 75, one end of the limiting pile 77 is inserted into the inner wall of the sliding groove 72, the other end of the limiting pile 77 abuts against the spring 76, the other end of the spring 76 abuts against the plug 74, the limiting pile 77 is connected and fixed with the through groove 75 through threads, the plug 74 plays a role in limiting the spring 76, and the spring 76 is used for applying elastic force to the limiting pile 77.

The working principle is as follows: during the use, be a pile of bipolar plate 2 and put on upper end plate 1, install a slice proton exchange membrane and two diffusion pieces between per two bipolar plate 2, adorn two spacing subassemblies 7 of working a telephone switchboard respectively on upper end plate 1 and lower end plate 3 again, install a spacing subassembly 7 of working a telephone switchboard earlier, insert in the spout 72 with preforming 8 again, detain the spacing subassembly of second working a telephone switchboard again, pass first fixing base 71, upper end plate 1, lower end plate 3 and second fixing base 71 and fasten through the nut with first connecting screw rod 4 in proper order at last.

Then the flat cable of the inspection circuit board is peeled off and then passes through the first connecting screw rod 4, the flat cable end is sequentially pressed into the inspection line positioning groove 29 by means of tweezers and other tools for positioning, the pressing sheet 8 is pushed towards the bipolar plate 2, the pressing sheet 8 presses the inspection line end, the reed 73 tightly supports the pressing sheet 8, the limiting pile 77 is inserted into the inner wall of the sliding groove 72 to limit the pressing sheet 8, the pressing sheet 8 is prevented from loosening, the inspection line is connected with the bipolar plate 2, the inspection circuit board is connected and fixed with the protective cover 6 through screws, the protective cover 6 is connected and fixed with the bipolar plate 2 and the lower end plate 3 through screws, and the assembly of the electric pile is completed.

Then, the fuel pipe, the water discharge pipe and the oxygen supply pipe are respectively connected with the terminal on the lower end plate 3, which is the prior art and not described herein, the hydrogen fuel enters the vent groove 210 through the fuel hole 22, flows into the flow guide groove 25 through the vent groove 210, is guided by the Y-axis flow channel 27, is shunted through the X-axis flow channel 26, uniformly flows onto the diffusion sheet, and is diffused onto the exchange membrane for exchange, and electrons are separated.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. Fuel cell is with patrolling and examining metal bipolar plate of wiring structure, including upper end plate (1), bipolar plate (2), lower end plate (3) and first connecting screw (4), bipolar plate (2) are stack from top to bottom and arrange, upper end plate (1) and lower end plate (3) set up respectively in the upper and lower both ends of bipolar plate (2), the side of upper end plate (1) and lower end plate (3) is fixed through first connecting screw (4), its characterized in that: the bipolar plate (2) comprises a plate body (21), the outer surface of the plate body (21) penetrates through and is provided with a fuel hole (22), a liquid discharge hole (23) and an oxygen hole (24), the outer surface of the plate body (21) is provided with a diversion trench (25) and a groove (28), the groove (28) surrounds the diversion trench (25), an X-axis flow channel (26) is uniformly distributed in the diversion trench (25), Y-axis flow channels (27) are arranged at two ends of the X-axis flow channel (26), the Y-axis flow channel (27) is in a wave-shaped structural design, an air vent groove (210) is formed in the inner wall of the fuel hole (22), the fuel hole (22) is communicated with the diversion trench (25) through the air vent groove (210), a routing line positioning groove (29) is formed in the side surface of the plate body (21), and a wiring limiting component (7) is inserted and combined on the outer surface of the lower end plate (3), the bottom end of the wiring limiting component (7) is movably connected with a pressing sheet (8) used for pressing the inspection wire head.

2. The metal bipolar plate of the routing inspection wiring structure for the fuel cell according to claim 1, wherein: the fuel holes (22) and the oxygen holes (24) are distributed on two sides of the liquid discharge hole (23), the number of the fuel holes (22), the number of the liquid discharge hole (23) and the number of the oxygen holes (24) are two, the two fuel holes (22), the two liquid discharge hole (23) and the two oxygen holes (24) are distributed at the left end and the right end of the X-axis flow channel (26), the two fuel holes (22) and the two oxygen holes (24) are distributed diagonally, the fuel holes (22), the two liquid discharge hole (23) and the two oxygen holes (24) are circular, the inner diameters of the fuel holes (22) and the oxygen holes (24) are equal, and the inner diameter of the fuel holes (22) is half of the inner diameter of the liquid discharge hole (23).

3. The metal bipolar plate of the routing inspection wiring structure for the fuel cell according to claim 1, wherein: the Y-axis flow channel (27) is uniformly provided with valley grooves, and the width of the valley grooves is gradually and uniformly increased from one side close to the vent groove (210) to one side far away from the vent groove (210).

4. The metal bipolar plate of the routing inspection wiring structure for the fuel cell according to claim 1, wherein: the bottom of patrolling and examining line constant head tank (29) is the arc, the left side slope of patrolling and examining line constant head tank (29) is steeper than the right side slope, and it is domatic to be longer than the left side domatic to patrol and examine line constant head tank (29) right side.

5. The metal bipolar plate of the routing inspection wiring structure for the fuel cell according to claim 1, wherein: the outer fixed surface of lower plate (3) has second connecting screw (5), the surface cover of second connecting screw (5) is equipped with protection casing (6), the both sides of protection casing (6) evenly pierce through and have seted up the louvre, the right side both ends of protection casing (6) all are connected fixedly with bipolar plate (2) and lower end plate (3) respectively through the screw.

6. The metal bipolar plate of the routing inspection wiring structure for the fuel cell according to claim 1, wherein: the wiring limiting assembly (7) comprises a fixed seat (71), the fixed seat (71) is L-shaped, the fixed seat (71) is made of metal materials, the material of the fixed seat (71) is the same as that of the plate body (21), the thickness of the fixed seat (71) is equal to that of the upper end plate (1) and the lower end plate (3), the fixed seat (71) is respectively connected and fixed with the bipolar plate (2) and the lower end plate (3) through a first connecting screw rod (4), the outer surface of the fixed seat (71) is provided with a sliding groove (72), the sliding groove (72) is obliquely arranged towards the direction of the bipolar plate (2), the pressing sheet (8) is connected with the sliding groove (72) in a sliding way, a reed (73) is arranged in the sliding groove (72), one end of the reed (73) is fixedly connected with the inner wall of the sliding groove (72), and the other end of the reed (73) is arc-shaped.

7. The metal bipolar plate of the routing inspection wiring structure for the fuel cell according to claim 6, wherein: lead to groove (75) has been seted up to the surface of fixing base (71), lead to groove (75) and spout (72) intercommunication, the inside that leads to groove (75) is provided with end cap (74), spring (76) and spacing stake (77), the one end of spacing stake (77) is inserted with the inner wall of spout (72) and is closed, and the other end and spring (76) of spacing stake (77) are contradicted, the other end and end cap (74) of spring (76) are contradicted, and spacing stake (77) are connected fixedly through screw and lead to groove (75).