A crucible for growing silicon carbide crystal by double heating method

Abstract

The application discloses a silicon carbide crystal double-heating-method growth crucible and particularly relates to the technical field of silicon carbide growth. The silicon carbide crystal double-heating-method growth crucible comprises a growth crucible, a preheating crucible arranged at the bottom of the growth crucible and a sealing cover arranged at the bottom in the preheating crucible, the outer sides of the growth crucible and the preheating crucible are independently provided with heating devices, the interiors of the growth crucible and the preheating crucible are provided with powder, and the inner top of the growth crucible is provided with a seed crystal. The silicon carbide crystal double-heating-method growth crucible further comprises conveying structure one, conveying structure two, an opening and closing assembly and a torsion spring rotating structure. The application solves the technical problems that the current silicon carbide powder heating presents an outward-to-inward heating trend, which is not conducive to the uniform gas-phase transportation of the powder to the seed crystal and the growth of larger crystals on the seed crystal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon carbide growth, and more particularly to a silicon carbide crystal double heating method growth crucible. BACKGROUND

[0002] As a representative of the third generation semiconductor material, silicon carbide has excellent properties such as large band gap, high saturated electron mobility, large breakdown field strength, and high thermal conductivity, and becomes an ideal material for manufacturing high-temperature, high-frequency, high-power, radiation-resistant, short-wavelength light-emitting, and optoelectronic integrated components, and is widely used in the fields of power electronics, radio frequency devices, and optoelectronic devices. The physical vapor transport method (PVT) is the main method for industrialized growth of silicon carbide crystals at present, which specifically refers to heating and vaporizing high-purity silicon carbide raw materials in a graphite crucible, and the gas molecules of the raw materials rise to meet the seed crystal to complete the crystallization, diameter expansion, and annealing process, so as to obtain a silicon carbide crystal.

[0003] At present, in the actual crystal growth process of silicon carbide, due to the peripheral distribution of the temperature field, the heating of the silicon carbide powder in the crucible shows a heating trend from the outside to the inside, so the temperature rising rate of the relative middle position of the powder in the crucible is lower than that of the two sides, and until the end of the crystal growth, the powder in the middle region of the crucible is prone to form a recrystallized polycrystalline silicon carbide region, which is not conducive to the uniform gas phase transport of the powder to the seed crystal; in addition, affected by factors such as temperature gradient, the size of the crucible limits the filling amount of the silicon carbide powder, so it is not easy to grow a larger crystal on the seed crystal, therefore, the present application provides a silicon carbide crystal double heating method growth crucible, which realizes uniform heating of the silicon carbide powder to realize uniform gas phase transport of the powder to the seed crystal, and increases the growth size of the crystal by rapidly replacing the powder to achieve the effect of material replenishment, so as to solve the above technical problems. SUMMARY

[0004] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present application provide a silicon carbide crystal double heating method growth crucible, and the technical problems to be solved by the present application are that the silicon carbide powder heating shows a heating trend from the outside to the inside, which is not conducive to the uniform gas phase transport of the powder to the seed crystal, and the seed crystal is not easy to grow a larger crystal.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a silicon carbide crystal double heating method growth crucible, comprising a growth crucible, a preheating crucible arranged at the bottom of the growth crucible, and a sealing cover arranged at the bottom of the preheating crucible, the outer sides of the growth crucible and the preheating crucible are independently provided with heating devices, the interiors of the growth crucible and the preheating crucible are provided with powder, and the inner top of the growth crucible is provided with a seed crystal.

[0006] A first conveying structure is disposed inside the growth crucible. The first conveying structure includes a material cylinder fixedly penetrating the bottom of the growth crucible, a material inlet formed on the outer surface of the material cylinder, and an auger shaft disposed inside the material cylinder. The shaft end of the auger shaft passes through the preheating crucible and the sealing cover in sequence and is rotatably connected to the preheating crucible and the sealing cover. A guide channel is fixedly connected to the bottom of the material cylinder, and the guide channel is located inside the preheating crucible.

[0007] The second conveying structure is disposed inside the preheating crucible and extends into the sealing cover and is connected to the growth crucible. The second conveying structure is used to convey the powder in the preheating crucible to the growth crucible. The second conveying structure and the preheating crucible are provided with damping sleeves.

[0008] An opening and closing assembly is slidably connected to the first material cylinder and located at the top of the second conveying structure. When the second conveying structure conveys powder into the growth crucible, the opening and closing assembly blocks the first material inlet.

[0009] A torsion spring rotating structure is provided on the second conveying structure and located inside the sealing cover. A push rod that is in movable contact with the torsion spring rotating structure is provided on the shaft of the first auger shaft.

[0010] In a preferred embodiment, the powder located in the growth crucible is above the top of the first material cylinder.

[0011] In a preferred embodiment, the second conveying structure includes a second material cylinder fixedly connected to the top of the sealing cover, a second material inlet formed on the outer surface of the second material cylinder, and a second auger shaft disposed inside the second material cylinder. The top end of the second material cylinder is fixedly extended to the inner bottom position of the growth crucible, and the second auger shaft is rotatably connected to the sealing cover.

[0012] In a preferred embodiment, the damping sleeve is disposed at the inner bottom of the preheating crucible, and the shaft end of the second auger shaft is rotatably connected to the damping sleeve.

[0013] In a preferred embodiment, a stirring blade is fixedly connected to the shaft of the auger shaft one, the stirring blade being located inside the preheating crucible and on one side of the feed inlet two.

[0014] In a preferred embodiment, the opening and closing assembly includes a sealing plate disposed on the outside of the first material cylinder and a top plate fixedly connected to the sealing plate. The top plate is conical in shape and is located at the top of the second material cylinder.

[0015] In a preferred implementation form, the outer surface of the first barrel is fixedly connected with a sliding rail, and the sealing plate is slidingly connected on the sliding rail and used for sealing the first material opening.

[0016] In a preferred implementation form, the torsion spring rotating structure comprises a fixed block fixedly connected on the second auger shaft and located in the sealing cover, a torsion spring rotating shaft arranged on the fixed block, and a push rod arranged on the torsion spring rotating shaft.

[0017] In a preferred implementation form, the fixed block is provided with a limiting groove, the torsion spring rotating shaft is arranged in the limiting groove, the push rod is movably connected with the limiting groove of the fixed block through the torsion spring rotating shaft, and the push rod arranged on the first auger shaft is movably contacted with the push rod.

[0018] Technical effects and advantages of the present application:

[0019] The silicon carbide crystal double-heating-method growth crucible provided by the present application comprises a growth crucible, a conveying structure one arranged in the growth crucible, a conveying structure two arranged in the growth crucible, a torsion spring rotating structure arranged in the growth crucible, and a push rod arranged on the first auger shaft.

[0020] The silicon carbide crystal double-heating-method growth crucible provided by the present application comprises a growth crucible, a conveying structure one arranged in the growth crucible, a conveying structure two arranged in the growth crucible, a torsion spring rotating structure arranged in the growth crucible, and a push rod arranged on the first auger shaft.

[0021] The silicon carbide crystal double-heating-method growth crucible provided by the present application comprises a growth crucible, a conveying structure one arranged in the growth crucible, a conveying structure two arranged in the growth crucible, a torsion spring rotating structure arranged in the growth crucible, and a push rod arranged on the first auger shaft.

[0022] The silicon carbide crystal double heating method growth crucible of the application, by setting the opening and closing assembly, in the process of flowing conveying of the powder in the growth crucible of the conveying structure, the opening and closing assembly can be away from the position of the first material port, so that the first material port can be conveniently entered by the powder conveyed upward by the first auger shaft, when the conveying structure two operates conveying, the powder sent into the growth crucible can conveniently lift the top plate, and the original powder in the growth crucible can continuously overflow the top of the first material cylinder, so that the inversion of the first auger shaft can quickly replace the powder in the growth crucible under the blocking effect of the sealing plate, so as to achieve the effect of quick replacement and supplement of the powder in the growth crucible, so as to meet the growth demand of the crystal size. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the overall perspective view of the application.

[0024] Figure 2 It is the structure diagram of the first auger shaft, push rod and second stirring blade of the application.

[0025] Figure 3 It is the perspective view of the first material cylinder, sealing plate and top plate of the application.

[0026] Figure 4 It is the perspective view of the torsion spring rotating structure of the application. Figure 1 It is the enlarged view of A part of the application.

[0027] Figure 5 It is the enlarged view of B part of the application. Figure 1

[0028] Figure 6 It is the perspective view of the torsion spring rotating structure of the application.

[0029] The figure mark is: 1, growth crucible; 2, preheating crucible; 3, first material cylinder; 31, first material port; 4, first auger shaft; 5, material guide channel; 6, sealing cover; 7, second material cylinder; 71, second material port; 8, second auger shaft; 9, sealing plate; 10, top plate; 11, torsion spring rotating structure; 111, fixed block; 112, torsion spring rotating shaft; 113, push rod; 12, push rod; 13, damping sleeve; 14, sliding rail; 15, stirring blade. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0031] In combination with Figures 1-6 ​The application provides a silicon carbide crystal double heating method growth crucible, which comprises a growth crucible 1, a preheating crucible 2 arranged at the bottom of the growth crucible 1, and a sealing cover 6 arranged at the inner bottom of the preheating crucible 2, heating devices are independently arranged at the outer sides of the growth crucible 1 and the preheating crucible 2, powder is arranged in the growth crucible 1 and the preheating crucible 2, and a seed crystal is arranged at the inner top of the growth crucible 1; the top of the growth crucible 1 is provided with a crucible cover, and the seed crystal is attached to the inner bottom of the crucible cover; the heating devices can be heaters, the two heating devices are arranged, one of the heating devices is used for heating the silicon carbide powder in the growth crucible 1, so that the powder can be conveniently heated and vaporized, and the other heating device is used for preheating the silicon carbide powder in the preheating crucible 2, so that the vaporization efficiency of the powder can be improved by conveying the preheated powder into the growth crucible 1, and the above-mentioned double heating effect can be achieved by arranging the two heating devices on the growth crucible 1 and the preheating crucible 2, so that the efficiency of the silicon carbide powder gas phase transmission and crystallization can be improved.

[0032] The silicon carbide crystal double heating method growth crucible further comprises a conveying structure one, a conveying structure two, an opening and closing assembly, and a torsion spring rotating structure 11.

[0033] The conveying structure one is arranged in the growth crucible 1, the conveying structure one comprises a cylinder one 3 penetrating through the inner bottom of the growth crucible 1, a material opening one 31 arranged on the outer surface of the cylinder one 3, and an auger shaft one 4 arranged in the cylinder one 3, the shaft end of the auger shaft one 4 penetrates through the preheating crucible 2 and the sealing cover 6 in sequence and is rotationally connected to the preheating crucible 2 and the sealing cover 6, the bottom of the cylinder one 3 is fixedly connected with a material guide channel 5, the material guide channel 5 is located in the preheating crucible 2, and the extension of one end of the auger shaft one 4 is connected with a rotary driving device, and the conveying direction of the auger shaft one 4 can be adjusted by adjusting the rotating direction of the auger shaft one 4.

[0034] Specifically, when the silicon carbide powder in the growth crucible 1 is subjected to gas phase treatment, the auger shaft one 4 is controlled to rotate, at this time, the opening and closing assembly is away from the position of the material opening one 31, so that the powder can continuously enter the cylinder one 3 through the position of the material opening one 31 and be conveyed to the top position of the cylinder one 3 by the spiral blades of the auger shaft one 4, the upward conveying mode of the auger shaft one 4 can prevent the powder in the growth crucible 1 from entering the material guide channel 5, so that the powder in the growth crucible 1 can change the stacking state from inside to outside, and the powder can be uniformly heated by cooperating with the heating effect of the heating device, thereby ensuring the uniformity of vaporization, improving the utilization rate of powder growth, and facilitating the effective delivery of gas phase components to the seed crystal.

[0035] The powder in the growth crucible 1 is higher than the top end of the cylinder one 3, and when the auger shaft one 4 is used for transferring the powder in the growth crucible 1, the arrangement of the powder in the growth crucible 1 being higher than the top end of the cylinder one 3 can facilitate the transfer of the powder into the material guide channel 5.

[0036] The second conveying structure is arranged in the preheating crucible 2 and extends into the sealing cover 6 and communicates with the growth crucible 1, and is used for conveying the powder in the preheating crucible 2 into the growth crucible 1.

[0037] The second conveying structure comprises a barrel 7 fixedly connected to the top of the sealing cover 6, a powder outlet 71 formed in the outer surface of the barrel 7, and an auger shaft 8 arranged in the barrel 7, the top end of the barrel 7 is fixedly penetrated into the inner bottom position of the growth crucible 1, the auger shaft 8 is rotatably connected to the sealing cover 6, and the powder in the preheating crucible 2 can enter the barrel 7 through the powder outlet 71, so that the helical blade of the auger shaft 8 can convey the preheated powder in the preheating crucible 2 upward into the growth crucible 1, and the powder after the gas phase is pushed upward to drive the effect of supplementing and replacing the powder in the growth crucible 1.

[0038] The damping sleeve 13 is arranged at the inner bottom position of the preheating crucible 2, and the shaft end of the auger shaft 8 is rotatably connected to the damping sleeve 13, and the arrangement of the damping sleeve 13 can increase the damping of the rotation of the auger shaft 8, and cooperate with the use of the torsional spring rotating structure 11, so that the problem of rotation of the auger shaft 8 in a single direction can be avoided, that is, when the auger shaft 1 transports the powder in the growth crucible 1 from inside to outside, the second conveying structure does not work at this time.

[0039] The shaft of the auger shaft 4 is fixedly connected with the stirring blade 15, and the stirring blade 15 is located in the preheating crucible 2, and the arrangement of the stirring blade 15 can promote the flowability of the powder in the preheating crucible 2 when the auger shaft 8 rotates to drive the stirring blade 15 to stir in the preheating crucible 2, so that the powder in the preheating crucible 2 can be conveniently fed into the powder outlet 71.

[0040] The opening and closing assembly is slidably connected to the barrel 3 and located at the top position of the second conveying structure, and the opening and closing assembly is sealed on the powder outlet 1 when the second conveying structure conveys the powder into the growth crucible 1.

[0041] Continuously referring to FIGS Figure 3 , Figure 4 The opening and closing assembly comprises a sealing plate 9 arranged on the outer side of the barrel 3 and a top plate 10 fixedly connected to the sealing plate 9, the top plate 10 is arranged in a conical structure, and the top plate 10 is located at the top position of the barrel 2, and the conical structure of the top plate 10 can facilitate the upward movement of the powder in the growth crucible 1, and the number of the sealing plate 9 in the application can be matched with the number of the powder outlet 1, when there are at least two powder outlets 1, a pair of sealing plates 9 can be connected by a fixing member, so that the lifting pressure of the top plate 10 can be improved when the auger shaft 8 conveys the powder upward, and the powder outlet 1 can be quickly closed.

[0042] The outer surface of the material cylinder one 3 is fixedly connected with a sliding rail 14, and the sealing plate 9 is slidingly connected on the sliding rail 14, and the sealing plate 9 is used for sealing the material port one 31, and the sliding rail 14 can make the sealing plate 9 realize the effect of vertical sliding.

[0043] Specifically, when the auger shaft one 4 in the material cylinder one 3 flows and transports the silicon carbide powder in the growth crucible 1, at this time, the sealing plate 9 on the sliding rail 14 is at the lowest position of the sliding rail 14, and is located below the side of the material port one 31, so that the powder in the growth crucible 1 can enter the material cylinder one 3 through the material port one 31, so as to realize the uniform gas phase by using the rotating auger shaft one 4 to transport the powder upward, and to guarantee the uniformity of heating; when the auger shaft two 8 transports the powder upward, at this time, the auger shaft one 4 is in the reverse downward transport process, when the auger shaft two 8 sends the powder in the preheating crucible 2 into the growth crucible 1 through the material cylinder two 7, the top plate 10 at the top of the material cylinder two 7 can be lifted up by the transported powder, and the new powder can push the old powder upward, so that the top plate 10 can drive the sealing plate 9 to slide on the sliding rail 14 and seal one side of the material port one 31, so that the auger shaft one 4 can displace the original powder in the growth crucible 1 at the top of the material cylinder one 3, and avoid the new powder entering the growth crucible 1 from the material cylinder two 7 from being discharged from the material port one 31, through the above steps, the silicon carbide powder in the preheating crucible 2 which is preheated by the heating device is transported into the growth crucible 1 and replaces the silicon carbide powder which has been gasified, so as to increase the crystallization area of the seed crystal and meet the growth demand of the crystal size.

[0044] Continue to refer to Figure 5 , Figure 6 , the torsional spring rotating structure 11 is arranged on the conveying structure two and located in the sealing cover 6, the shaft of the auger shaft one 4 is provided with a push rod 12 which is in movable contact with the torsional spring rotating structure 11, the torsional spring rotating structure 11 comprises a fixed block 111 which is fixedly connected on the shaft of the auger shaft two 8 and located in the sealing cover 6, a torsional spring rotating shaft 112 which is arranged on the fixed block 111, and a push rod 113 which is arranged on the torsional spring rotating shaft 112.

[0045] The fixed block 111 is provided with a limiting groove, the torsional spring rotating shaft 112 is arranged in the limiting groove, the push rod 113 is rotatably connected in the limiting groove of the fixed block 111 through the torsional spring rotating shaft 112, the push rod 12 arranged on the auger shaft one 4 is in movable contact with the push rod 113, and the limiting groove can be used for limiting the rotating path of the push rod 12, so that the push rod 12 rotates in the interval of the limiting groove, and the damping force of the damping sleeve 13 is greater than the elastic force of the torsional spring in the torsional spring rotating shaft 112, so that the advantage of the design is that when the auger shaft one 4 rotates in the upward transport direction, the auger shaft two 8 can be limited from rotating by the damping of the damping sleeve 13, so as to avoid the auger shaft two 8 from transporting the preheated powder into the growth crucible 1.

[0046] Specifically, when the auger shaft one 4 rotates in the upward conveying direction, the push rod 12 can rotate and contact the lever 113 at this time, and the damping force of the damping sleeve 13 is greater than the elastic force of the torsional spring in the torsional spring rotating shaft 112. The lever 113 can rotate in the limiting groove through the torsional spring rotating shaft 112 until the rotating position of the end of the lever 113 is out of the rotating path of the end of the push rod 12. In this way, the lever 113 can reset the position, and the auger shaft two 8 does not rotate. When the auger shaft one 4 rotates in the downward conveying direction, the push rod 12 can rotate and contact the lever 113 at this time, and the push rod 12 can directly drive the fixed block 111 to rotate through the lever 113 under the action of the limiting groove limiting the rotating path of the lever 113. In this way, the auger shaft two 8 can rotate in the upward conveying direction in the barrel two 7, and the preheated powder in the preheating crucible 2 can be continuously conveyed upward by the auger shaft two 8 through the material port two 71. At the same time, the preheated powder conveyed into the growing crucible 1 can lift the top plate 10, and the material port one 31 is blocked by the sealing plate 9. In this way, the auger shaft one 4 can convey the powder above the top of the barrel one 3 downward and collect it in the area of the material guide channel 5.

[0047] In the embodiment, the uniform heating of the silicon carbide powder is realized to ensure the uniform gas phase transportation of the powder to the seed crystal, and the effect of replacing and supplementing the powder is realized to increase the growth size of the crystal, which solves the technical problems that the silicon carbide powder heating has a heating trend from the outside to the inside, which is not conducive to the uniform gas phase transportation of the powder to the seed crystal, and it is not easy to grow larger crystals on the seed crystal.

[0048] It is worth noting that the conveying structure two in the present application can be appropriately increased in number according to the amount of silicon carbide powder, and the torsional spring rotating structure 11 should be matched with the number of the conveying structure two. In addition, in order to ensure the conveying efficiency of the conveying structure two, the number of the torsional spring rotating structure 11 and the push rod 12 is increased to contact and cooperate, which can improve the conveying efficiency of the auger shaft two 8. In addition, the torsional spring rotating structure 11 and the push rod 12 are used to drive the auger shaft two 8 to rotate, that is, when the auger shaft one 4 rotates in the downward or upward conveying direction, the rotating speed is higher than that of the auger shaft two 8. Therefore, the size of the barrel one 3 and the auger shaft one 4 is smaller than that of the barrel two 7 and the auger shaft two 8 to meet the input and balance of the replacement and supplement of the powder.

Claims

1. A crucible for growing silicon carbide crystals by a double heating method, characterized by: The utility model provides a crystal growth device, including growth crucible (1), set up in the preheating crucible (2) of growth crucible (1) bottom and set up in the inner bottom of preheating crucible (2) seal cover (6), the outside of growth crucible (1) and preheating crucible (2) are independently provided with heating device, the inside of growth crucible (1) and preheating crucible (2) are provided with powder, and the inner top of growth crucible (1) is provided with seed crystal; The conveying structure one is arranged in the growth crucible (1), and the conveying structure one includes a first material cylinder (3) fixedly penetrating the inner bottom of the growth crucible (1), a first material opening (31) formed in the outer surface of the first material cylinder (3), and an auger shaft one (4) arranged in the first material cylinder (3). The shaft end of the auger shaft one (4) penetrates the preheating crucible (2) and the seal cover (6) in sequence and is rotationally connected to the preheating crucible (2) and the seal cover (6). The bottom of the first material cylinder (3) is fixedly connected with a material guide channel (5), and the material guide channel (5) is located in the preheating crucible (2). The conveying structure two is arranged in the preheating crucible (2) and extends into the seal cover (6) and is connected with the growth crucible (1). The conveying structure two is used for conveying the powder in the preheating crucible (2) into the growth crucible (1). The conveying structure two and the preheating crucible (2) are provided with a damping sleeve (13). The opening and closing assembly is slidably connected to the first material cylinder (3) and is located at the top of the conveying structure two. When the conveying structure two conveys the powder into the growth crucible (1), the opening and closing assembly is blocked on the first material opening (31). The torsional spring rotating structure (11) is arranged on the conveying structure two and is located in the seal cover (6). The shaft of the auger shaft one (4) is provided with a push rod (12) in movable contact with the torsional spring rotating structure (11).

2. The crucible for growing silicon carbide crystal by double heating method according to claim 1, wherein: The powder in the growth crucible (1) is higher than the top end of the first material cylinder (3).

3. The crucible for growing silicon carbide crystal by double heating method according to claim 1, wherein: The conveying structure two includes a second material cylinder (7) fixedly connected to the top of the seal cover (6), a second material opening (71) formed in the outer surface of the second material cylinder (7), and an auger shaft two (8) arranged in the second material cylinder (7). The top end of the second material cylinder (7) penetrates to the inner bottom of the growth crucible (1). The auger shaft two (8) is rotationally connected to the seal cover (6).

4. The crucible for growing silicon carbide crystal by double heating method according to claim 3, wherein: The damping sleeve (13) is arranged at the inner bottom of the preheating crucible (2). The shaft end of the auger shaft two (8) is dampingly rotationally connected to the damping sleeve (13).

5. The crucible for growing silicon carbide crystal by double heating method according to claim 3, wherein: The shaft of the auger shaft one (4) is fixedly connected with stirring blades (15). The stirring blades (15) are located in the preheating crucible (2) and are located at one side of the second material opening (71).

6. The crucible for growing silicon carbide crystal by double heating method according to claim 3, wherein: The opening and closing assembly comprises a sealing plate (9) arranged outside the first barrel (3) and a top plate (10) fixedly connected to the sealing plate (9), wherein the top plate (10) is arranged in a conical structure and is located at the top of the second barrel (7).

7. The crucible for growing silicon carbide crystal by double heating method according to claim 6, wherein: An outer surface of the first barrel (3) is fixedly connected with a sliding rail (14), and the sealing plate (9) is slidingly connected to the sliding rail (14), and the sealing plate (9) is used for sealing the first material port (31).

8. The crucible for growing silicon carbide crystal by double heating method according to claim 3, wherein: The torsion spring rotating structure (11) comprises a fixed block (111) fixedly connected to the second auger shaft (8) and located in the sealing cover (6), a torsion spring rotating shaft (112) arranged on the fixed block (111), and a push rod (113) arranged on the torsion spring rotating shaft (112).

9. The crucible for growing silicon carbide crystal by double heating method according to claim 8, wherein: The fixed block (111) is provided with a limiting groove, the torsion spring rotating shaft (112) is arranged in the limiting groove, the push rod (113) is rotatably connected to the limiting groove of the fixed block (111) through the torsion spring rotating shaft (112), and the push rod (12) arranged on the first auger shaft (4) is in movable contact with the push rod (113).

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