JP2010076310A - Preliminary molding mold of pimple for crawlers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preliminary molding mold of a pimple for a crawler wherein a pimple for a crawler stored in a cavity of a circular inner mold, etc. a non-vulcanized guide rubber and the like can be molded at a sufficient accuracy by a pair of up-and-bottom preliminary molding molds and a volume of molded non-vulcanized guide rubber, etc. can be coincided at high accuracy to a capacity of a cavity of a circular inner mold, etc. so that high uniformity of a rubber crawler product can be maintained and there is no fair of unexpectable deletion of a driving pimple on the inner circumference surface of the rubber crawler product. <P>SOLUTION: A pimple for a crawler having a predetermined shape and size is preliminarily molded by a non-vulcanized rubber in a cavity 14 separated between the upper mold 12 and the bottom mold 13, wherein the bottom mold 13 is cut in five-divided structures displaceable to forward-backward direction with the central part 13a remaining, and a part of the opposite divided displaceable parts 13b, 13c is used as a fixed material remaining in a compartment position of the cavity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

This invention is used for molding an unvulcanized rubber crawler, and is provided with an unvulcanized driving rubber protrusion disposed on a portion on the inner peripheral surface side of the rubber crawler, or an outer peripheral surface side of the rubber crawler. The present invention relates to a pre-molding mold for crawler rubber projections for pre-molding uncured lug rubber projections and other crawler rubber projections arranged separately in a separate setup and with high accuracy. Proposes a technique for smoothly and surely removing unvulcanized rubber protrusions preformed in a cavity from a mold, especially a lower mold.
Of course, the present invention can also be applied to manufacturing methods other than the so-called circular vulcanization manufacturing method.

  For example, a rubber crawler without a cored bar is superior in high-speed running performance, has low vibration and noise, and has a smaller weight than a rubber crawler with a cored bar. It has been collected.

  As a method of manufacturing such a coreless rubber crawler, for example, each of a plurality of indentations provided in the circumferential direction of a circular inner mold having a cylindrical shape is intended for automation of rubber crawler manufacturing. Then, unvulcanized guide rubber as an example of a crawler projection, which is used as a drive projection after vulcanization molding, is inserted, and an unvulcanized rubber sheet is wound around them to a required thickness, In addition, a reinforcing layer made of steel cord, organic fiber cord or the like is wound around the unvulcanized rubber sheet as necessary, and outer rubber that contributes to the formation of lugs or the like on the outer peripheral side thereof Is wound to a required thickness to form an unvulcanized rubber crawler, and then an outer mold that cooperates with the circular inner mold, such as an outer mold segment, is pressed around the molded rubber crawler to Vulcanized rubber claw In addition to typed molded lugs or the like, a method of vulcanizing the rubber crawler over the entire circumference has been proposed.

  By the way, according to this method, it is important to increase the uniformity of the product rubber crawler that the guide rubber inserted into the recess provided in the circular inner mold is exactly matched to each recess. If there is an excess or deficiency in the volume of the rubber inserted in the depression, irregularities will occur on the surface of the unvulcanized rubber sheet, reinforcing layer, etc. that are wound after that, and the unvulcanized However, there is a problem that the uniformity of the rubber crawler of this product and the product rubber crawler is inevitably lowered.

In relation to this point, Patent Document 1 discloses a molding roll in which a plurality of recesses for forming drive protrusions are engraved on a surface, which is formed by rolling an inner rubber sheet integrally provided with drive protrusions on one side surface, A flat roll provided close to and close to the mold roll, a pressure roll that presses the inner cloth on the other smooth side surface of the inner rubber sheet near the mold roll, and the inner cloth A pre-forming apparatus comprising an unwinding roll and a guide roll is disclosed. According to this, a driving protrusion is formed on one side surface while filling an unvulcanized rubber into a driving protrusion forming recess of a molding roll. Technology has been developed to improve workability and productivity by rolling the integrally molded inner-layer rubber sheet, and to improve product accuracy by preventing product defects. It is.
Japanese Patent Laid-Open No. 10-100300

  However, the prior art described in Patent Document 1 originally does not preliminarily mold crawler protrusions in a cavity between upper and lower molds that are paired under separate steps, but a molding roll and a flat roll. Crawler projections in that the unvulcanized rubber material is only filled into the recesses for forming the drive projections of the mold roll while sequentially introducing the unvulcanized rubber material that has been heated from the gap between For example, unvulcanized drive projections cannot be preformed with as much precision as expected, and therefore the uniformity of product rubber crawlers cannot also be improved as expected. was there.

  In addition, in this prior art, since there is no provision for reliably integrating the unvulcanized drive protrusion formed in the drive protrusion forming recess with the roll-formed inner rubber sheet, for example, in the recess If the drive protrusion of the material is adhered to the wall surface side of the recess by a negative pressure adsorption force and / or adhesive force with a force larger than the adhesion force to the inner rubber sheet side, There is a problem that the drive protrusions are lost from the product crawler because the sulfur drive protrusions are not integrated with the inner rubber sheet and remain attached to the recesses for forming the drive protrusions of the molding roll. .

According to the present invention, a crawler protrusion, such as an unvulcanized guide rubber or the like, which is housed in the circular inner mold or other depressions described above as the proposed technique, is sufficiently high with a preformed mold that is paired vertically. In addition to molding accurately, the pre-molded guide rubber can always remain at a predetermined position in the mold, and as a result, it is extremely easy to automate a series of operations using a robot. In addition, the volume of the molded unvulcanized guide rubber is matched with the hollow volume of the circular inner mold with high accuracy to ensure high uniformity of the product rubber crawler, and the inner circumference of the product rubber crawler It is an object of the present invention to provide a preforming mold for crawler projections, in particular, a lower mold, in which there is no risk of unexpected loss of drive projections on the surface.
By the way, it goes without saying that the preforming mold of the present invention can be applied to a manufacturing method other than the circular vulcanization method for crawlers.

  The crawler projection preforming mold of the present invention is a crawler projection having a predetermined shape and size made of unvulcanized rubber in a cavity defined between an upper mold and a lower mold. The unvulcanized guide rubber is pre-molded, and the part of the lower die that contributes to the cavity section has a five-part structure that can be displaced in the front-rear direction or the left-right direction, leaving the center part. A part of the divided displacement portions that form a pair opposite to each other is formed as a pair or a plurality of pairs of fixed finger members that remain at the partition position of the cavity.

  Here, preferably, the central portion is a cavity bottom forming member, and a rising tongue piece that contributes to a partition of the cavity is provided at the central portion adjacent to the divided displacement portions facing each other.

  Preferably, drive means for moving the central portion up and down between a lowered position contributing to the cavity section and an elevated position is provided.

  By the way, the shape of the cavity may be an inverted frustum shape, for example, an inverted pyramid shape or a truncated cone shape, and the upper die may be automatically or driving means when the upper die is opened. It is preferable to provide an ejector that protrudes toward the lower mold side, and the mold is an injection mold.

  In the preforming mold according to the present invention, in particular, the part of the lower mold that contributes to the cavity section is made into a five-part structure that can be displaced in the front-rear direction or the left-right direction, leaving the central part. When removing pre-molded crawler projections, such as unvulcanized guide rubber, from the cavity, each of the pair of split displacement parts facing each other is displaced in a direction away from the central part. Thus, the unvulcanized guide rubber is reliably left on the central portion, so that the influence of the adhesive force, the adsorption force, and the like exerted on the unvulcanized guide rubber by the divided displacement portions can be completely removed.

  And in this case, by making the part of the divided displacement parts facing each other into fixed finger members that remain at the partitioning position of the cavity, the unvulcanized guide rubber on the central part is also fixed by the fixed finger members that make a pair. Therefore, it is possible to effectively restrain displacement or deformation to any one of the divided displacement portions, so that the unvulcanized guide rubber can be connected to the central portion without being affected by the separation displacement of the divided displacement portion. On top, it can be maintained in an upright position.

Thus, the unvulcanized guide rubber as a crawler projection can always be reliably left at a fixed position as expected, and the removal of the guide rubber by a robot or the like is surely simple. can do.
In addition, since the volume of the unvulcanized guide rubber molded in the mold can accurately correspond to the cavity, it can be used in a predetermined recess such as a circular inner mold with high accuracy. The uniformity of the product crawler can be sufficiently increased.

  And furthermore, by pre-molding the unvulcanized guide rubber into all the recesses of the circular inner mold, etc., by vulcanizing and bonding each guide rubber to the unvulcanized rubber sheet, etc. Since it can be set as the drive protrusion which protrudes to the inner peripheral surface side of the crawler, the possibility of the drive protrusion missing from the product crawler can be sufficiently removed.

Here, when the central portion is a cavity bottom forming member, after the separation displacement of the split displacement portion, the unvulcanized guide rubber is not yet added to the central portion regardless of the overall shape of the unvulcanized guide rubber. The sulfur guide rubber can be supported in a sufficiently stable posture, and the subsequent removal operation of the guide rubber can be further facilitated.
In addition, when a rising tongue piece is provided at a position adjacent to the divided displacement portion facing each other in the central portion, the rising portion is separated when the divided displacement portions forming a pair are separated from the central portion. Under the cooperative action of the tongue piece and the fixed finger member, it is possible to more effectively prevent the unvulcanized guide rubber on the central portion from being jointly displaced, collapsed, deformed, etc. by the divided displacement portion.

  By the way, when the driving means for moving up and down the central part itself supporting the pre-molded unvulcanized guide rubber in an upright posture is provided, the driving means is related to the shape of the unvulcanized guide rubber. The unvulcanized guide rubber on the central part is raised relative to each of the fixed finger member and the cavity partition part other than the divided displacement part based on the upward displacement of the central part by the operation of Since the sticking of the guide rubber to those members, etc. can be released, the guide rubber can be taken out from the lower mold, and the unvulcanized guide rubber can be projected upward from the lower mold. Together, it is possible to perform more smoothly by the action of a smaller force.

And when the shape of the cavity is a truncated cone shape such as an inverted truncated cone shape or a truncated pyramid shape, the guide rubber is held upright with a small area and a central portion where the unvulcanized guide rubber has a small sticking force. Since it can be supported in the posture, the unvulcanized guide rubber can be easily taken out from the lower mold with a small force.
Further, in this case, when the central portion is lifted and displaced together with the unvulcanized guide rubber by the driving means, the unvulcanized guide rubber can be completely separated from the fixed finger member and other cavity partition portions. Therefore, the unvulcanized guide rubber can be taken out from the lower mold more easily.

In the above-described mold, when the upper mold is provided with an ejector that protrudes to the lower mold side automatically or by operating means when the upper mold is opened, a preformed unvulcanized guide is provided. The rubber can be prevented from adhering to the upper mold, and the guide rubber can be reliably left on the lower mold.
In this case, the ejector having a dimension that straddles the cavity in either direction prevents the unvulcanized guide rubber from being scratched, and the ejector includes an upper mold. This is preferable for automatically retracting and retracting into the upper mold accompanying the closing.

  And furthermore, when the mold to be used in the present invention is an injection mold, the rubber material is sufficiently softened by heating to such an extent that fluidity is improved but vulcanization does not proceed, By injecting it into the cavity from the injection nozzle, it can be fully spread to all corners of the cavity regardless of the shape of the cavity under high fluidity, and the cavity can be completely filled. Therefore, even if the cavity shape is complicated, the intended unvulcanized guide rubber can always be preformed with high accuracy.

  FIG. 1 is a cross-sectional perspective view partially illustrating a core crawler-less rubber crawler suitable for manufacturing using a preforming die according to the present invention in a winding position around a sprocket (not shown). The middle 1 is an endless steel cord reinforcing layer, and the reference numeral 2 is an organic fiber cord, for example, three reinforcing plies arranged on the outer periphery of the steel cord reinforcing layer 1. Each is shown.

  Here, the steel cord reinforcing layer 1 and each reinforcing ply 2 are both embedded in the rubber elastic body 3 and the inner surface of the rubber elastic body 3 has, for example, a width of the rubber elastic body 3. Drive protrusions 4 that are located in the center portion of the direction and engage with the drive sprocket are provided at predetermined intervals in the circumferential direction, and the central portion of the rubber elastic body 3 in the width direction is provided on the outer peripheral surface of the rubber elastic body 3 A plurality of lugs 5 which are formed in a staggered manner in the respective side regions and act on the road surface are provided at a predetermined interval in the circumferential direction, thereby forming a coreless rubber crawler 6. To do.

  The coreless rubber crawler 6 having such a configuration is vulcanized and molded with the circular inner mold as described above and the outer mold cooperating with the inner mold, and with the inner mold, the drive protrusion and the like, and In the case of forming lugs and the like with the outer mold, for example, when molding an unvulcanized rubber crawler on the inner mold, as described above, a plurality of driving protrusions 4 provided on the inner mold are formed. The unvulcanized guide rubber as an example of the crawler protrusion, which will later become the drive protrusion 4, is inserted into each of the individual recesses in advance so as to accurately match the individual recesses. Therefore, here, an example in which the unvulcanized guide rubber that is fitted into each of the depressions is preformed into a shape and dimensions that accurately correspond to the depressions will be described below.

2 to 5 are operation process diagrams schematically showing a preforming mold used for this purpose, in which (a) is a longitudinal sectional view seen from the front side, and (b) is (a) ) Shows a longitudinal sectional view taken along line bb.
In the drawing, reference numeral 11 denotes an injection mold as an example of a preforming mold. The injection mold 11 is formed between an upper mold 12 and a lower mold 13 and upper and lower molds 12 and 13. And a injection nozzle 15 for injecting a fluidized rubber material into the cavity 14.

  Here, at least one figure is formed on the upper mold 12 of such an injection mold 11 so as to form a part of the cavity molding surface in the closed position of the upper and lower molds 12 and 13 as shown in FIG. Then, two ejectors 16 are arranged, and each of the ejectors 16 has a dimension that straddles the cavity 14 in a longitudinal sectional view as seen from the front side, for example, and each ejector 16 is placed in the upper mold 12. A plurality of spring members 17, for example, coil springs, that are normally urged toward the lower mold 13 side are housed and arranged per ejector 16.

  In the injection mold 11 having such a schematic structure, in order to reduce or suppress sticking of the unvulcanized guide rubber preformed in the cavity 14 to the cavity wall surface, the entire cavity wall surface or Further, a release layer of polytetrafluoroethylene or the like can be provided at a required portion.

  Here, when pre-molding an unvulcanized guide rubber as an example of the crawler protrusion using the injection mold 11 as described above, first, the molds of the upper and lower molds 12 and 13 as shown in FIG. In a closed state, a rubber material imparted with high fluidity is injected into the cavity 14 at a predetermined pressure through the injection nozzle 15, and the rubber material is sufficiently distributed throughout the cavity 14. Then, the rubber material is solidified based on the cooling of the mold 11 to obtain an unvulcanized guide rubber having a predetermined shape and size.

  Thereafter, under the mold opening operation of the upper mold 12, the ejector 16 provided on the upper mold 12 is automatically protruded and displaced from the upper mold 12 as shown in FIG. Thus, the pre-molded unvulcanized guide rubber 20 is reliably left on the lower mold 13.

  In this case, when the ejector 16 is subjected to such a projecting displacement under the action of the spring member 17, the air passing through the spring member housing portion of the upper die 12 is moved into the ejector 16 and the remaining portion of the upper die 12. Therefore, even if the remaining portion of the upper mold 12 is adsorbed to the unvulcanized guide rubber 20 by negative pressure, the upper mold remaining portion is separated from the unvulcanized guide rubber 20. The displacement is always performed smoothly and reliably.

When the upper mold 12 rises more than the free length of the spring member 17 with respect to the lower mold 13 by continuing such mold opening operation of the upper mold 12, as shown in FIGS. The ejector 16 is also separated from the surface of the unvulcanized rubber 20, and the unvulcanized guide rubber 20 remains on the lower mold 13 independently of the ejector 16.
Here, the smooth and reliable separation of the ejector 16 from the unvulcanized guide rubber 20 is achieved by setting the contact area between the ejector 16 and the unvulcanized guide rubber 20 sufficiently small in advance. Even if the vulcanized guide rubber 20 sticks to the ejector 16 or is adsorbed under negative pressure, it is sufficient to make the sticking force smaller than the force corresponding to the weight of the unvulcanized guide rubber 20 or the like. Can be secured.

In this way, in order to smoothly and surely remove the unvulcanized guide rubber 20 that always remains on the lower mold 13 from the lower mold 13, the cavity of the lower mold is shown. 14 is divided into a central portion 13a that forms all or most of the bottom surface of the cavity 14, and a split displacement portion 13b that is displaceable in the front-rear direction, facing the central portion 13a. The left and right fixed portions 13d and 13e that contribute to the section of the other portion of the cavity 14 are provided.
As a result, the lower mold 13 has a five-part structure composed of a total of five parts.

  Here, in the drawing, the left and right parts, which are fixed parts, are opposed to each other with a central part 13a therebetween, and are divided displacement parts that can be displaced in the left-right direction. It can also be a fixed part.

  By the way, both the front-rear direction portion and the left-right direction portion that are located across the central portion 13a can be divided displacement portions. In this case, however, the mold structure is complicated in order to achieve the same effect. There is a tendency to become too much.

In addition, in the drawing, a part of the front and rear divided displacement portions 13b and 13c facing each other is used as the fixed finger members 21 and 22 that remain at the partition positions of the cavity 14, and these fixed finger members 21 are provided. , 21 as shown in FIGS. 3 to 5, the split displacement portions 13 b and 13 c are displaced away from the central portion 13 a and remain in the initial setting position.
Here, the contact width of each of the fixed finger members 21 and 22 with the unvulcanized guide rubber 20 corresponds to the mutual displacement of the respective divided displacement portions 13b and 13c, and the unvulcanized guide rubber 20 is While the width is such that the positioning can be surely restrained without deformation, displacement or the like at the preforming position, the sticking force of the unvulcanized guide rubber 20 to the fixed finger members 21 and 22 is such that the guide rubber 20 It is preferable that the width of the fixed finger members 21 and 22 is such that the separation as expected without deformation or the like can be performed sufficiently smoothly.

  Further, in the illustrated embodiment, the center portion 13a that forms the bottom of the cavity 14 is adjacent to the mutually opposed divided displacement portions 13b and 13c, as shown in FIG. 5 (b). Standing tongue pieces 23 and 24 are provided.

  More preferably, there is provided drive means (not shown), which can be a cylinder or the like, in which the central part 13a is raised and lowered as illustrated in FIG. 5, and preferably as shown in FIG. The cavity 14 to be formed has an inverted frustum shape such as an inverted truncated pyramid shape or a truncated cone shape.

  Further, as shown in the figure, the upper mold 12 is provided with an ejector 16 that is projected and displaced to the lower mold side as the upper mold 12 is opened, and the preforming mold is an injection molding mold 11 as shown in the figure. It is preferable that

  Using the lower mold 13 having the above-described configuration, the unvulcanized guide rubber 20 as a preform is left on the lower mold 13 under the action of the ejector 16 disposed on the upper mold 12. When removing from the lower mold 13, first, as shown in FIG. 3 (b), the split displacement portions 13 b and 13 c are separated and displaced in the front-rear direction with respect to the central portion 13 a. The displacement portions 13b and 13c are removed from sticking to the unvulcanized guide rubber 20, and the displacement, deformation and the like of the guide rubber 20 at this time are shown in the figure in the center portion of the cavity 14 in the left-right direction. In addition to being restrained by a pair of fixed finger members 21 and 22 that contribute to the section of the above, it is also restrained by a pair of rising tongues 23 and 24 that are also formed in the central portion 13a. 20, on the central portion 13a to form the bottom portion of the cavity 14, thereby reliably remain in a stable upright position.

  In this case, when the shape of the cavity 14 is an inverted frustum shape as shown in the figure, the adhesive force between the central portion 13a and the unvulcanized guide rubber 20 is made sufficiently small so that the lower part of the guide rubber 20 Removal from the mold 13 can be made easier.

  By the way, in this case, the unvulcanized guide rubber 20 is applied to the contact surfaces of the fixed finger members 21 and 22 and the rising tongue pieces 23 and 24 and the contact surfaces of the left and right fixed portions 13d and 13e. More preferably, after the ejector 16 is separated from the unvulcanized guide rubber 20 as shown in FIG. 4 on the basis of the upward displacement of the upper mold 12 as shown in FIG. Then, the central portion 13a is moved up and displaced together with the unvulcanized guide rubber 20 by a driving means (not shown), whereby the unvulcanized guide rubber 20 is adhered to the fixed finger members 21, 22 and the left and right fixed members 13d, 13e. Remove.

  When the unvulcanized guide rubber 20 is subjected to such upward displacement, the shape of the cavity, and thus the shape of the guide rubber 20 is a frustum shape as shown in the figure, the unvulcanized guide rubber 20 In addition to being able to remove the sticking to the fixed finger members 21 and 22 and the left and right fixing members 13d and 13e, as is apparent from FIG. And 13d, 13e can be lifted to the upper side of the cavity partition surface, so that the unvulcanized guide rubber 20 and their members 21, 22 under the lifted displacement state of the central portion 13a The occurrence of unintentional resticking with 13d and 13e can also be reliably removed.

  Accordingly, here, the pre-molded unvulcanized guide rubber 20 remains on the central portion 13a of the lower die 13 always reliably and in the desired form under a small sticking force thereto. Thus, the automatic removal of the unvulcanized guide rubber 20 using a robot or the like can be performed without causing deformation or the like in the unvulcanized guide rubber 20 by the action of a sufficiently small force. Moreover, it can always be performed smoothly without failure of taking out.

  Further, here, by molding the unvulcanized guide rubber 20 in the vulcanization molding die 11 as a preforming mold, the volume, dimensions, shape, etc. of the unvulcanized rubber 20 as a preformed product are Since it can be matched with the volume of the depression provided in the circular inner mold or the like with high accuracy, the uniformity of the product rubber crawler can be sufficiently increased.

  Furthermore, by simply inserting the pre-molded unvulcanized guide rubber 20 into all of the recesses of the circular inner mold or the like, the individual unvulcanized guide rubber 20 is vulcanized and adhered to the rubber sheet or the like. The drive claw that protrudes toward the inner peripheral surface of the product rubber crawler can prevent the vulcanization adhesion between the unvulcanized guide rubber 20 and the rubber sheet from occurring. The possibility of missing drive protrusions can be sufficiently eliminated.

By the way, as described above, after finishing one preforming and taking out the preform from the mold, the constituent parts 13a, 13b, 13c of the lower mold 13 are returned to their original positions, As shown in FIG. 2, the upper mold 12 is again lowered and displaced with respect to the lower mold 13, and the next preforming is started under the predetermined cavity 14.
In this downward displacement of the upper mold 12 with respect to the lower mold 13, for example, the ejector 16 that is in a projecting displacement state due to the pressing action of the spring member 17 is brought into contact with the lower mold 13 and the spring. By performing backward displacement against the spring force of the member 17, the upper mold 12 can be automatically returned to a predetermined position.

  Although the present invention has been described above based on the illustrated examples, for example, the crawler projections used as lugs of the product rubber crawlers are pre-molded by separate setup in the same manner as described above, regardless of the presence or absence of the core metal. You can also.

  Moreover, it is also possible to arrange two or more pairs of fixed finger members which are only one pair in the figure.

It is a section perspective view which illustrates partially using the suitable rubber crawler manufactured using the metallic mold concerning this invention. It is sectional drawing which shows the formation process of the cavity by an up-and-down type | mold. It is sectional drawing which shows the operation process of an ejector, and the displacement process of a division | segmentation displacement part. It is sectional drawing which shows the separation state from a preforming product of an ejector. It is sectional drawing which shows the raising process of the bottom part of a lower mold | type.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel cord reinforcement layer 2 Reinforcement ply 3 Rubber elastic body 4 Drive protrusion 5 Lug 6 Core metal-less rubber crawler 11 Injection mold 12 Upper mold 13 Lower mold 13a Center part 13b, 13c Split displacement part 13d, 13e Left and right fixed part 14 Cavity 15 Injection nozzle 16 Ejector 17 Spring member 20 Unvulcanized guide rubber 21, 22 Fixed finger members 23, 24 Rising tongue

Claims (6)

A mold for preforming crawler protrusions having a predetermined shape and dimensions with unvulcanized rubber in a cavity defined between an upper mold and a lower mold,
The lower mold has a five-divided structure that can be displaced in the front-rear direction or the left-right direction, leaving the center portion, and a crawler that serves as a fixed finger member that retains a part of the divided displacement portions facing each other at the partitioning position of the cavity Pre-molding mold for projection.   2. The crawler projection preliminary according to claim 1, wherein the central portion is used as a bottom forming member of the cavity, and a rising tongue is provided at a location adjacent to the divided displacement portion facing each other at the central portion. Molding mold.   The preforming mold for crawler projections according to claim 1 or 2, further comprising driving means for moving the central portion up and down.   The preform for the crawler projection according to any one of claims 1 to 3, wherein the cavity has an inverted frustum shape.   The preforming mold according to any one of claims 1 to 4, wherein the upper mold is provided with an ejector that projects toward the lower mold when the upper mold is opened.   The preforming mold according to any one of claims 1 to 5, wherein the mold is an injection mold.

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