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CN-122008453-A - Mold exhaust device for vulcanization molding of rubber track and vulcanization molding method

CN122008453ACN 122008453 ACN122008453 ACN 122008453ACN-122008453-A

Abstract

The invention relates to the technical field of rubber track preparation, in particular to a mold exhaust device for vulcanization molding of a rubber track and a vulcanization molding method. The invention sets micro-roughness exhaust belt in the easy trapped air area such as iron teeth, circumferentially distributing light to seal the spigot, and arranges shallow exhaust buffer groove/ring groove on the parting surface, and can select roughness gradient, step isolation belt and staggered spigot to form labyrinth micro-gap channel. The structure utilizes surface tension/capillary action to directionally guide and discharge trapped gas, avoids glue columns, hole blockage and shutdown, obviously reduces bubbles, scorching marks and flash, shortens maintenance time and improves vulcanization stability and qualification rate, and is suitable for a thick-glue deep-tooth crawler belt mould.

Inventors

  • WANG XIAO
  • HE MINGMING
  • WANG XUXIAN
  • SONG XIAOHUA
  • FANG CHONG

Assignees

  • 中策橡胶集团股份有限公司

Dates

Publication Date
20260512
Application Date
20260120

Claims (10)

  1. 1. A mould exhaust apparatus for rubber track vulcanization molding, including relative last mould and lower mould that sets up, iron tooth die cavity and tread die cavity that enclose jointly to and be located the exhaust area between die cavity and the die joint, its characterized in that: The vent area is processed into a micro-roughness vent zone extending along the cavity to the parting surface on at least one side of the cavity surface, wherein the surface roughness of the vent zone meets rz=15-60 μm and Ra=1.0-5.0 μm; The circumference of the exhaust belt is surrounded by a smooth sealing spigot area, and the surface roughness Ra of the spigot area is less than or equal to 0.4 mu m; A parting surface exhaust buffer groove is arranged at the parting surface corresponding to the outer end of the exhaust belt, the depth of the buffer groove is 0.03-0.15 mm, and the width of the buffer groove is 0.5-2.0 mm; And through holes penetrating through the die body are not formed in the iron tooth type cavity and the adjacent area of the iron tooth type cavity.
  2. 2. The mold vent of claim 1, wherein the microroughness vent strip is formed by a composite process of discharge texturing, filament spark, sand blasting or shot blasting, the micro-groove array having a groove width of 10 to 50 μm, a groove depth of 10 to 40 μm, and a pitch of 50 to 200 μm.
  3. 3. The mold venting device of claim 1, wherein the micro-roughness venting zone is radially disposed from the tip, root fillet and sidewall corners of the iron tooth cavity to the parting surface, and has a roughness gradient along the venting direction, i.e., 1.0-2.0 μm near the cavity end Ra, gradually transitioning to 3.0-5.0 μm toward the parting surface.
  4. 4. The mold vent apparatus of claim 1, wherein the vent belt has an effective width W in the width direction of 2 to 6mm, and smooth spigot rings each 0.3 to 1.0mm wide are provided on both sides for restricting molten rubber from entering the vent belt.
  5. 5. The mold vent apparatus of claim 1 wherein said parting surface vent buffer groove interfaces with a circumferentially communicating annular vent ring groove having a depth of 0.03 mm to 0.10mm and a width of 0.8mm to 1.5mm to maintain a stable micro-gap vent path under mold clamping pressure.
  6. 6. The mold venting device of claim 1, wherein a replaceable venting insert is arranged at the top of the iron tooth or in the transition area of the bolt hole and the reinforcing rib, the molding surface of the insert is prefabricated with micro-textures consistent with parameters of a venting belt, and quick assembly and disassembly are realized through a positioning cone or a positioning pin for maintenance.
  7. 7. The mold venting device of claim 1, wherein the upper mold and the lower mold are arranged in a staggered manner at the venting zone, wherein one side of the venting zone is provided with a micro-roughness venting zone, the other side of the venting zone corresponds to a smooth sealing seam allowance zone, and the two are combined to form a labyrinth micro-gap channel so as to reduce the risk of surface embossing of the product.
  8. 8. The mold vent of claim 1, wherein a step spacer having a height of 0.05 to 0.20mm is provided between the vent strip and the iron tooth cavity, the spacer being a smooth finish for trapping a small amount of glue entering the edge of the vent strip and blocking further diffusion thereof.
  9. 9. The mold vent apparatus of claim 1, wherein the vent belt is preferably disposed at the leading and trailing edges of the track running direction, at the corner region R of the iron tooth root and at the turning region of the tread pattern groove, and the total area of the vent belt is 0.5% -4% of the projected area of the mold cavity.
  10. 10. A vulcanization molding method of a rubber track using the exhaust device according to any one of claims 1 to 9, comprising: S1) processing a micro-roughness exhaust belt in the area of the upper die and the lower die, which needs to be exhausted, and forming a buffer groove on the parting surface; s2) die assembly is carried out, unvulcanized rubber is injected or pressed, and the die assembly pressure is 10-25 MPa; S3) guiding out trapped gas by utilizing a micro-channel of an exhaust belt and a parting surface buffer groove in the vulcanization process; S4) demolding after vulcanization, wherein the exhaust belt can enter the next cycle only by conventional wiping or sandblasting and light cleaning due to the fact that no through hole exhaust rubber column exists.

Description

Mold exhaust device for vulcanization molding of rubber track and vulcanization molding method Technical Field The invention relates to the technical field of rubber track preparation, in particular to a mold exhaust device for vulcanization molding of a rubber track and a vulcanization molding method. Background In the vulcanization molding process of the rubber track, unvulcanized rubber materials can wrap the air in the cavity to form trapped air in the mold closing and mold filling stages, if the air is not exhausted smoothly, the defects of bubbles, lack of rubber, scorching marks, surface marks and the like of products are often caused, and the defects are more prominent especially at complex geometric positions such as R angle of the root part of an iron tooth, sharp-topped transition zone, rib position intersection and the like. In order to solve the problem of trapped air, the industry generally adopts a parting surface vent groove, a through hole vent, a micropore vent plug, a microstructure or texture introducing means on a cavity surface, but each scheme still has trade-off among the vent efficiency, the maintenance cost and the appearance of the product. First, a land vent is one of the most common solutions. Chinese patent CN204109288U discloses a die with stepped vent grooves, wherein two-stage structures of an anti-overflow part and a vent part are arranged at the end of a parting surface, the typical dimensions are 0.05-0.07 mm deep in the anti-overflow part and 0.15-0.20 mm deep in the vent part, and the die is communicated with the outside through a vent hole at the end, so that the anti-overflow and the vent efficiency are both considered. In addition, chinese patent CN206317314U proposes that a flat bottom notch is provided at the sealing position of the parting plane and extends outward into a slope notch, and the depth thereof gradually increases along the outward direction, so as to improve the continuity of the exhaust channel in the parting plane direction. Also, chinese patent CN206383450U expands the coverage of parting surface exhaust by forming a curved exhaust network around the cavity with a main flow channel and a plurality of split flow channels. The method is simple in structure realization, but the risks of insufficient exhaust paths of the near-cavity sections, sensitive parting surface machining tolerance and assembly coaxiality and easy generation of parting surface marks/burrs under high-pressure mold filling still exist in the positions of air bags such as thick glue areas or deep iron tooth cavities and the like only depending on parting surface channels. Secondly, the direct communication of the mold cavity with the outside is also a common idea by adopting a through hole/ventilation piece. Chinese patent CN100343033C, CN100343034C proposes to provide a micro-porous air permeable member and a micro-porous air vent on the working surface of the mold cavity, and to fit with an air vent groove communicated with the micro-porous air vent, thereby realizing direct air venting from the working surface in a mold such as rubber, plastic, etc. For tires and large plastic parts, microporous exhaust plugs made of sintered porous materials are also presented, for example, chinese patent CN2385862Y gives examples of pore sizes, dimensions and materials in different product scenarios to improve exhaust flux and reduce surface defects. However, the common pain points of the through hole/ventilation part scheme in the field of rubber products are that a rubber column is easy to form and is broken by pulling during demolding, the subsequent plugging of holes is easy to occur, a channel of a porous part is easy to pollute under the action of long-term hot pressing and formula educts, frequent disassembly and cleaning or replacement are required, the maintenance cost is high, and meanwhile, the boundary of an orifice or an insert can have adverse effects on appearance and stress continuity. Thirdly, the use of cavity surface microstructure and texture to improve mold filling flow and promote gas escape along the surface is also increasingly applied to tire/rubber molds. Taking chinese patent CN102248616a as an example, a micro-protrusion is provided on the molding surface of the tire mold to form a rough surface molding portion, which gives a quantization range of protrusion height of 10-300 μm, and indicates that the rough surface can form a flow path beneficial to air discharge along the circumferential direction, so as to inhibit poor joint and appearance defect caused by residual air. The idea of forming a microscale ventilation channel by controlling surface roughness or texture is known, but the prior disclosures focus on pattern appearance uniformity and general flow improvement, and are relatively limited for the directional exhaust design of deep cavity parts such as track iron teeth, the coupling relation with parting surface micro grooves and engineering windows avoiding l