Clamping fixture for punching side face of nut
By designing a clamping fixture for drilling holes on the side of nuts, multiple nuts can be processed simultaneously, reducing processing costs and improving production efficiency, thus solving the problem of low efficiency in conventional tooling operations.
Patent Information
- Application Number
- CN202423065669.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-12
AI Technical Summary
The conventional tooling for drilling holes on the side of nuts requires separate operation, resulting in high processing costs and low production efficiency.
Design a clamping fixture including a base plate, a front drilling table, a chip removal table, and a rear cylinder mounting table. The fixture enables simultaneous machining of multiple nuts through the drilling fixture plate, is equipped with a cover plate to fix the nuts, has a chip removal table to remove waste chips, uses a cylinder to push in and push out the nuts, and uses a lubricating fluid circulation block to ensure machining quality.
This technology enables the simultaneous processing of multiple nuts, reducing processing costs, improving production efficiency, and ensuring the processing quality of the nuts through effective chip removal and lubrication.
Smart Images

Figure CN223603920U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to punch processing fixture technical field, especially a kind of clamping fixture for nut side punching. BACKGROUND
[0002] Conventional nut side punching is usually separate punching tooling, one drilling equipment corresponds to one tooling, and one worker is needed to operate each equipment during operation, which greatly increases processing cost and cannot guarantee production efficiency, so the clamping fixture needs to be reformed to solve the above problems. SUMMARY
[0003] The utility model provides a kind of clamping fixture for nut side punching, with the characteristics of improving hole position, reducing processing cost, improving production efficiency and the like.
[0004] The utility model discloses a kind of clamping fixture for nut side punching, including bottom plate, front drilling station, chip removal station and rear cylinder installation platform, the upper end surface front part of the bottom plate is vertically installed with front drilling station, the upper end surface rear part of the bottom plate is installed with rear cylinder installation platform, the upper end surface of the front drilling station is installed with drilling fixture plate, the upper end surface of the drilling fixture plate is installed with cover plate, the upper end surface of the drilling fixture plate is provided with several left and right side arrangement drilling processing positions, the cover plate is provided with several processing holes corresponding to drilling processing position one by one, the front and rear ends of the drilling processing position are penetrated front drilling station, the front side of the front drilling station is provided with chip removal station, the upper end surface front part of the chip removal station is installed with front cylinder installation faceplate, the rear end surface of the front cylinder installation faceplate is installed with several front cylinders corresponding to drilling processing position one by one in parallel, the upper part of the rear cylinder installation platform is installed with several main shafts forward and corresponding to drilling processing position one by one rear top-in cylinder in parallel.
[0005] The technical scheme is provided with drilling fixture plate to facilitate the placement of multiple nuts, so that multiple nuts can be processed synchronously during processing, thereby improving processing efficiency and reducing processing cost, the cover plate is installed to facilitate the fixing of nuts, the chip removal station is provided to facilitate the discharge of waste chips generated during drilling, the rear top-in cylinder is installed to facilitate the top-in of nuts into drilling processing position, the front cylinder is provided to facilitate the top-out of nuts in drilling processing position, and the processing hole is provided to facilitate the extension of drill rod.
[0006] As a supplement to the technical solution, the middle part of the drilling processing position is provided with a downward extending chip removal channel, the lower part of the chip removal table is provided with a plurality of chip removal openings corresponding to the drilling processing positions, and the chip removal channel and the chip removal openings are communicated.
[0007] In the technical solution, the chip removal channel is arranged to facilitate the falling of the waste chips, and the chip removal opening is arranged to facilitate the removal of the waste chips.
[0008] As a supplement to the technical solution, the lower part of the rear cylinder mounting table is provided with a plurality of waste chip pushing-out cylinders arranged side by side, the waste chip pushing-out cylinders correspond to the drilling processing positions one by one, the main shaft of the waste chip pushing-out cylinder faces forward, a waste chip pushing block is mounted on the main shaft of the waste chip pushing-out cylinder, the front end of the waste chip pushing block penetrates through the lower end of the chip removal channel and extends into the chip removal opening.
[0009] In the technical solution, the waste chip pushing-out cylinder is arranged to push the waste chip pushing block, the waste chip pushing block is arranged to push the waste chips in the lower part of the chip removal channel out, and the waste chip pushing block is arranged to push the waste chips to the chip removal opening.
[0010] As a supplement to the technical solution, the rear side of the front drilling table is provided with an up-and-down moving product transfer platform, the upper end surface of the product transfer platform is provided with a plurality of product placing grooves corresponding to the drilling processing positions one by one, the product transfer platform is arranged to facilitate the overall storage of the nuts, and the product placing grooves are arranged to facilitate the fixed placement of the nuts.
[0011] As a supplement to the technical solution, the both ends of the product transfer platform are provided with guide column structures vertically extending to the bottom plate, the upper end surface of the bottom plate and the lower part of the product transfer platform are provided with a lifting cylinder with the main shaft facing upward, the main shaft of the lifting cylinder is connected with the lower end surface of the product transfer platform, when the product transfer platform rises to the limit position, the rear top-in cylinder, the product placing grooves and the drilling processing positions are on the same horizontal line.
[0012] In the technical solution, the guide column structure is arranged to facilitate the stable operation of the product transfer platform, and the lifting cylinder is arranged to ensure that the product transfer platform can be aligned with the drilling processing position.
[0013] As a supplement to the technical solution, the main shaft of the front cylinder adopts a cylindrical rod structure, the cylindrical rod structure is tightly matched with the front end of the drilling processing position, the front end of the cylindrical rod structure is provided with a limiting protrusion, when the main shaft of the front cylinder is completely extended, the rear end of the product in the drilling processing position extends from the rear end of the drilling processing position, and the extension length of the product is less than half of the total length of the product.
[0014] The cylindrical rod structure is arranged to facilitate pushing the nut out of the cylindrical rod structure, and is tightly matched to block the part.
[0015] As a supplement to the technical scheme, the front side of the drilling clamp plate and the cover plate is uniformly provided with a plurality of lubricating liquid circulating blocks corresponding to the drilling processing positions, the left upper part and the lower part of the lubricating liquid circulating block are respectively provided with an upper part channel and a lower part channel penetrating through the lubricating liquid circulating block, adjacent upper part channels and adjacent lower part channels are connected through pipelines, the left end of the upper part channel and the lower part channel of the lubricating liquid circulating block at the leftmost end of the drilling clamp plate is provided with an inlet pipeline, the right end of the upper part channel and the lower part channel of the lubricating liquid circulating block at the rightmost end of the drilling clamp plate is provided with an outlet pipeline, and the inlet pipeline and the outlet pipeline are connected with an external lubricating oil circulating pump.
[0016] In the technical scheme, the lubricating liquid circulating block is used to facilitate the introduction of lubricating liquid into the drilling processing position, so that the position can be lubricated and cooled at the same time, ensuring that the generated waste chips do not wear out the nut during drilling, and ensuring the processing quality of the nut, the upper part channel is arranged to fill the drilling processing position with lubricating liquid, and the lower part channel is arranged to fill the chip removal position with lubricating liquid.
[0017] As a supplement to the technical scheme, the rear end upper part of the lubricating liquid circulating block is provided with a convex column structure embedded in the drilling clamp plate and the cover plate, an upper chamber communicating with the upper part channel is arranged in the upper part of the lubricating liquid circulating block, a channel hole penetrating through the front and rear sides of the lubricating liquid circulating block is arranged in the middle part of the convex column structure, four lubricating liquid injection holes surrounding the channel hole are arranged on the rear end face of the convex column structure, the lubricating liquid injection holes adopt an inclined hole structure with the front end inclined towards the middle part, and the rear end of the lubricating liquid injection hole communicates with the upper chamber.
[0018] In the technical scheme, the convex column structure is used to facilitate the docking with the drilling clamp plate and the cover plate, the upper chamber is arranged to facilitate the accommodation of lubricating liquid, and the lubricating liquid injection holes are arranged as injection channels extending into the drilling processing position, and the four cross-shaped arranged lubricating liquid injection holes facilitate the uniform injection of lubricating liquid.
[0019] As a supplement to the technical scheme, the rear side lower end of the lubricating liquid circulating block is provided with a lower part outlet communicating with the lower part channel, a ring of sealing ring mounting grooves is arranged on the outer ring of the lower part outlet, the front side of the drilling clamp plate is provided with a lower part injection channel docked with the lower part outlet, the rear end of the lower part injection channel adopts a tapered hole structure with a gradually reduced hole diameter, the tapered hole structure extends from the side wall of the chip removal channel, and the tapered hole structure is arranged to control the injection speed of the lubricating liquid.
[0020] Beneficial effects: the utility model relates to a kind of clamping fixture for nut side punching, by setting drilling fixture plate to place multiple nuts conveniently, so that during processing, the synchronous processing of multiple nuts can be carried out, to realize improving processing efficiency, reduce processing cost, by installing cover plate, to facilitate the fixing of nut, by setting chip removal platform to facilitate the discharge of waste chip generated during drilling, by installing rear top-in air cylinder, conveniently top nut into drilling processing position, by setting front air cylinder, conveniently eject nut in drilling processing position, by setting processing hole, conveniently drill rod is inserted, with the characteristics of improving hole position, reduce processing cost, improve production efficiency etc. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 It is the structure view of the utility model;
[0022] Figure 2 It is the front view of the utility model;
[0023] Figure 3 It is the plan view of the utility model;
[0024] Figure 4 It is the plan view of the utility model after removing cover plate;
[0025] Figure 5 It is the structure view of the waste chip push-out air cylinder of the utility model;
[0026] Figure 6 It is the plan view of the front drilling table of the utility model;
[0027] Figure 7 It is the structure view of the utility model Figure 6 A-A direction section view in the utility model;
[0028] Figure 8 It is the structure view of the lubricating liquid circulation block of the utility model;
[0029] Figure 9 It is the back view of the lubricating liquid circulation block of the utility model;
[0030] Figure 10 It is the structure view of the utility model Figure 9 C-C direction section view in the utility model;
[0031] Figure 11 It is the structure view of the utility model Figure 9 B-B direction section view in the utility model.
[0032] Figure: 1, base plate, 2, rear cylinder mounting table, 3, front drilling table, 4, chip removal table, 5, drilling fixture plate, 6, cover plate, 7, product transfer platform, 8, chip removal port, 9, product placement groove, 10, front cylinder, 11, front cylinder mounting panel, 12, cylindrical rod structure, 13, drilling processing position, 14, chip removal channel, 15, waste pushing cylinder, 16, rear top-in cylinder, 17, waste pushing block, 18, guide post structure, 19, lubricating liquid circulation block, 20, upper channel, 21, lower channel, 22, cooling pipeline, 23, tapered hole structure, 24, lower liquid outlet, 25, sealing ring mounting groove, 26, protruding column structure, 27, lubricating liquid injection hole, 28, upper chamber, 29, processing hole. DETAILED DESCRIPTION
[0033] The utility model is further explained below in combination with specific embodiments. It should be understood that these embodiments are only used for illustrating the utility model and are not used for limiting the scope of the utility model. In addition, it should be understood that after reading the content taught by the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms also fall within the scope defined by the claims attached to the present application.
[0034] The embodiment of the utility model relates to a clamping fixture for nut side hole drilling, such as Figure 1 As shown in Figure 4, it comprises a base plate 1, a front drilling table 3, a chip removal table 4 and a rear cylinder mounting table 2, the upper end face of the front part of the base plate 1 is vertically provided with the front drilling table 3, the upper end face of the rear part of the base plate 1 is provided with the rear cylinder mounting table 2, the upper end face of the front drilling table 3 is provided with the drilling fixture plate 5, the upper end face of the drilling fixture plate 5 is provided with the cover plate 6, a plurality of drilling processing positions 13 are arranged side by side on the upper end face of the drilling fixture plate 5, a plurality of processing holes 29 corresponding to the drilling processing positions 13 are arranged on the cover plate 6, the front and rear ends of the drilling processing positions 13 penetrate through the front drilling table 3, the front side of the front drilling table 3 is provided with the chip removal table 4, the upper end face of the front part of the chip removal table 4 is provided with the front cylinder mounting panel 11, a plurality of front cylinders 10 corresponding to the drilling processing positions 13 are arranged side by side on the rear end face of the front cylinder mounting panel 11, a plurality of rear top-in cylinders 16 are arranged side by side on the upper part of the rear cylinder mounting table 2, the main shafts of the rear top-in cylinders 16 face forward and correspond to the drilling processing positions 13 one by one.
[0035] The technical scheme is characterized in that the drilling clamp plate 5 is arranged to facilitate the placement of multiple nuts, so that multiple nuts can be machined synchronously during the machining process, thereby improving the machining efficiency and reducing the machining cost.
[0036] As a supplement to the technical scheme, the middle part of the drilling machining position 13 is provided with a downward extending chip removal channel 14, and the lower part of the chip removal table 4 is provided with a plurality of chip removal openings 8 corresponding to the drilling machining positions 13 one by one.
[0037] In the technical scheme, the chip removal channel 14 is arranged to facilitate the falling of the waste chips, and the chip removal opening 8 is arranged to facilitate the discharge of the waste chips.
[0038] As a supplement to the technical scheme, the lower part of the rear cylinder mounting table 2 is provided with a plurality of waste chip pushing out cylinders 15 arranged side by side, the waste chip pushing out cylinders 15 correspond to the drilling machining positions 13 one by one, the main shaft of the waste chip pushing out cylinder 15 faces forward, and the waste chip pushing block 17 is mounted on the main shaft of the waste chip pushing out cylinder 15, the front end of the waste chip pushing block 17 passes through the lower end of the chip removal channel 14 and extends into the chip removal opening 8.
[0039] In the technical scheme, the waste chip pushing out cylinder 15 is arranged to push the waste chip pushing block 17, the waste chip pushing block 17 is arranged to push the waste chips in the lower part of the chip removal channel 14, and the waste chip pushing block 17 is arranged to push the waste chips to the chip removal opening 8.
[0040] As shown in Figure 5 As a supplement to the technical scheme, the rear side of the front drilling table 3 is provided with an up-down moving product transfer platform 7, the upper end surface of the product transfer platform 7 is provided with a plurality of product placement grooves 9 corresponding to the drilling machining positions 13 one by one, the product transfer platform 7 is arranged to facilitate the overall storage of nuts, and the product placement grooves 9 are arranged to facilitate the fixed placement of nuts.
[0041] As a supplement to the technical solution, the product transfer platform 7 is provided with a guide column structure 18 extending vertically to the bottom plate 1 at both ends, a lifting cylinder with the main shaft upward is installed on the upper end surface of the bottom plate 1 and below the middle of the product transfer platform 7, the main shaft of the lifting cylinder is connected with the lower end surface of the product transfer platform 7, when the product transfer platform 7 rises to the limit position, the rear top-in cylinder 16, the product placing groove 9 and the drilling processing position 13 are on the same horizontal line.
[0042] In the technical solution, the guide column structure 18 is installed to facilitate the stable operation of the product transfer platform 7, and the lifting cylinder is installed to ensure that the product transfer platform 7 can be aligned with the drilling processing position 13.
[0043] As a supplement to the technical solution, the main shaft of the front cylinder 10 adopts a cylindrical rod structure 12, the cylindrical rod structure 12 is tightly matched with the front end of the drilling processing position 13, the front end of the cylindrical rod structure 12 is provided with a limiting protrusion, when the main shaft of the front cylinder 10 is fully extended, the rear end of the product in the drilling processing position 13 extends out of the rear end of the drilling processing position 13, and the extension length of the product is less than half of the total length of the product.
[0044] In the technical solution, the cylindrical rod structure 12 is provided to facilitate the pushing of the nut out of the cylindrical rod structure 12, and is tightly matched to block the part, and the limiting protrusion is provided to limit the cylindrical rod structure 12.
[0045] As a supplement to the technical solution, the front side of the drilling clamp plate 5 and the cover plate 6 is uniformly provided with a plurality of lubricating liquid circulating blocks 19 corresponding to the drilling processing positions 13, the left upper part and the lower part of the lubricating liquid circulating block 19 are respectively provided with an upper part channel 20 and a lower part channel 21 penetrating through the lubricating liquid circulating block 19, adjacent upper part channels 20 and adjacent lower part channels 21 are connected by pipelines, the left end of the upper part channel 20 and the lower part channel 21 of the lubricating liquid circulating block 19 located at the leftmost end of the drilling clamp plate 5 is provided with an inlet pipeline, and the right end of the upper part channel 20 and the lower part channel 21 of the lubricating liquid circulating block 19 located at the rightmost end of the drilling clamp plate 5 is provided with an outlet pipeline, the inlet pipeline and the outlet pipeline are connected with an external lubricating oil circulating pump.
[0046] In the technical solution, the lubricating liquid circulating block 19 is used to facilitate the introduction of lubricating liquid into the drilling processing position 13, so that the place can be lubricated and cooled at the same time, to ensure that the generated waste will not wear out the nut during drilling, and to ensure the processing quality of the nut, the upper part channel 20 is provided to fill the drilling processing position 13 with lubricating liquid, and the lower part channel 21 is provided to fill the chip removal position with lubricating liquid.
[0047] As shown inFigures 9-11 As shown in the figure, as a supplement to the technical solution, the rear end upper part of the lubricating liquid circulating block 19 is provided with a convex column structure 26 embedded in the drill hole clamp plate 5 and the cover plate 6, the upper part of the lubricating liquid circulating block 19 is provided with an upper chamber 28 communicated with the upper channel 20, the middle part of the convex column structure 26 is provided with a channel hole penetrating the front and rear sides of the lubricating liquid circulating block 19, the rear end surface of the convex column structure 26 is provided with four lubricating liquid injection holes 27 around the channel hole, the lubricating liquid injection hole 27 adopts an inclined hole structure with the front end inclined to the middle part, and the rear end of the lubricating liquid injection hole 27 is communicated with the upper chamber 28.
[0048] In the technical solution, the convex column structure 26 is used to facilitate the butt joint of the drill hole clamp plate 5 and the cover plate 6, the upper chamber 28 is used to facilitate the accommodation of lubricating liquid, and the lubricating liquid injection hole 27 is used as an injection channel extending into the drill hole processing position 13. The four cross-shaped lubricating liquid injection holes 27 facilitate uniform injection of lubricating liquid.
[0049] As shown in the figure Figure 6 and Figure 7 As a supplement to the technical solution, the rear side lower end of the lubricating liquid circulating block 19 is provided with a lower liquid outlet 24 communicated with the lower channel 21, the outer ring of the lower liquid outlet 24 is provided with a ring of sealing ring installation grooves 25, the front side of the drill hole clamp plate 5 is provided with a lower injection channel 22 butt jointed with the lower liquid outlet 24, the rear end of the lower injection channel 22 adopts a taper hole structure 23 with a gradually reduced hole diameter, and the taper hole structure 23 extends from the side wall of the chip removal channel 14. By providing the taper hole structure 23, the injection speed of the lubricating liquid is controlled.
Claims
1. A clamping jig for side punching of a nut, characterized by: The utility model relates to a drilling and dust removal device, including bottom plate (1), front drilling platform (3), dust removal platform (4) and rear cylinder installation platform (2), the upper end surface front vertical installation of bottom plate (1) is with front drilling platform (3), the upper end surface rear installation of bottom plate (1) is with rear cylinder installation platform (2), the upper end surface of front drilling platform (3) is installed with drilling fixture plate (5), the upper end surface of drilling fixture plate (5) is installed with cover plate (6), the upper end surface of drilling fixture plate (5) is provided with a plurality of left and right side arrangement drilling processing position (13), the cover plate (6) is provided with a plurality of and drilling processing position (13) one to one corresponding processing hole (29), the front and rear end of drilling processing position (13) penetrates front drilling platform (3), the front side of front drilling platform (3) is provided with dust removal platform (4), the upper end surface front of dust removal platform (4) is installed with front cylinder installation faceplate (11), the rear end surface of front cylinder installation faceplate (11) is installed with a plurality of and drilling processing position (13) one to one corresponding front cylinder (10) side by side, the upper part of rear cylinder installation platform (2) is installed with a plurality of rear top -in cylinder (16) and drilling processing position (13) one to one corresponding forward main shaft.
2. The clamping fixture for side punching of a nut according to claim 1, characterized in that: The middle part of drilling processing position (13) is provided with the dust removal channel (14) that extends downward, and the lower part of dust removal platform (4) is provided with a plurality of dust removal openings (8) corresponding to the drilling processing positions (13), and the dust removal channel (14) is communicated with the dust removal openings (8).
3. The clamping fixture for side punching of a nut according to claim 2, characterized in that: The lower part of rear cylinder installation platform (2) is provided with a plurality of scrap pushing cylinders (15) arranged side by side, the scrap pushing cylinders (15) correspond to the drilling processing positions (13), the main shafts of the scrap pushing cylinders (15) are forward, and the main shafts of the scrap pushing cylinders (15) are provided with scrap pushing blocks (17), the front ends of the scrap pushing blocks (17) penetrate the lower ends of the dust removal channels (14) and extend into the dust removal openings (8).
4. The clamping fixture for side punching of nuts according to claim 1, characterized in that: The rear side of front drilling platform (3) is provided with a product transfer platform (7) moving up and down, and the upper end surface of the product transfer platform (7) is provided with a plurality of product placing grooves (9) corresponding to the drilling processing positions (13) arranged side by side.
5. The clamping fixture for side punching of nuts according to claim 4, characterized in that: The both ends of the product transfer platform (7) are provided with guide column structures (18) vertically extending to the bottom plate (1), the upper end surface of the bottom plate (1) is provided with a lifting cylinder with an upward main shaft below the middle part of the product transfer platform (7), the main shaft of the lifting cylinder is connected to the lower end surface of the product transfer platform (7), when the product transfer platform (7) is lifted to the limit position, the rear top-in cylinder (16), the product placing groove (9) and the drilling processing position (13) are on the same horizontal line.
6. The clamping fixture for side punching of nuts according to claim 1, characterized in that: The main shaft of the front cylinder (10) adopts a cylindrical rod structure (12), the cylindrical rod structure (12) is tightly matched with the front end of the drilling processing position (13), the front end of the cylindrical rod structure (12) is provided with a limiting protrusion, when the main shaft of the front cylinder (10) is fully extended, the rear end of the product in the drilling processing position (13) is extended from the rear end of the drilling processing position (13), and the extension length of the product is less than half of the total length of the product.
7. The clamping fixture for side punching of nuts according to claim 2, characterized in that: The front side of the drilling clamp plate (5) and the cover plate (6) is uniformly provided with a plurality of lubricating liquid circulating blocks (19) corresponding to the drilling processing positions (13), the left upper part and the lower part of the lubricating liquid circulating block (19) are respectively provided with an upper part channel (20) and a lower part channel (21) penetrating through the lubricating liquid circulating block (19), adjacent upper part channels (20) and adjacent lower part channels (21) are connected through pipelines, the left end of the upper part channel (20) and the lower part channel (21) of the lubricating liquid circulating block (19) located at the leftmost end of the drilling clamp plate (5) is provided with an inlet pipeline, and the right end of the upper part channel (20) and the lower part channel (21) of the lubricating liquid circulating block (19) located at the rightmost end of the drilling clamp plate (5) is provided with an outlet pipeline, the inlet pipeline and the outlet pipeline are connected with an external lubricating oil circulating pump.
8. The clamping fixture for side punching of a nut according to claim 7, characterized in that: The rear end upper part of the lubricating liquid circulating block (19) is provided with a convex column structure (26) embedded in the drilling clamp plate (5) and the cover plate (6), an upper part cavity (28) in communication with the upper part channel (20) is arranged in the upper part of the lubricating liquid circulating block (19), a channel hole penetrating through the front and rear sides of the lubricating liquid circulating block (19) is arranged in the middle part of the convex column structure (26), four lubricating liquid injection holes (27) surrounding the channel hole are arranged on the rear end face of the convex column structure (26), the lubricating liquid injection hole (27) adopts an inclined hole structure with the front end inclined to the middle part, and the rear end of the lubricating liquid injection hole (27) is in communication with the upper part cavity (28).
9. The clamping fixture for side punching of nuts according to claim 7, characterized in that: The rear side lower end of the lubricating liquid circulating block (19) is provided with a lower part outlet (24) in communication with the lower part channel (21), a ring of sealing ring mounting grooves (25) is arranged on the outer ring of the lower part outlet (24), the front side of the drilling clamp plate (5) is provided with a lower part injection channel (22) butted with the lower part outlet (24), the rear end of the lower part injection channel (22) adopts a tapered hole structure (23) with a gradually reduced hole diameter, and the tapered hole structure (23) extends from the side wall of the chip removal channel (14).