JP4890149B2 - Method for producing elastic crawler - Google Patents

Description

  The present invention relates to a method for manufacturing an elastic crawler.

An elastic crawler to be mounted on a farm vehicle or construction machine traveling device is, for example, an endless belt-like rubber crawler body with an endless tensile body embedded therein and a plurality of lugs on the outer peripheral surface of the crawler body. And a driving projection is formed on the inner peripheral surface (see, for example, Patent Document 1).
Conventionally, such an elastic crawler is manufactured as follows, for example.
First, an unvulcanized rubber material of a predetermined length is attached to the inner peripheral side and outer peripheral side of a tensile body made of steel cord, etc., and the tensile body is heated with a heating mold consisting of an upper mold and a lower mold. The unvulcanized rubber material and the tensile body are vulcanized and molded by heating the heating mold. In the heating mold, recesses are formed at a predetermined pitch so that lugs and drive protrusions are formed on the vulcanized belt-like rubber-like body.

A cooling mold is provided at the end of the heating mold, and the end of the vulcanized belt-like rubber-like body is cooled by the cooling mold and is in an unvulcanized or semi-vulcanized state. It becomes.
Then, the end portion of the unvulcanized or semi-vulcanized belt-like rubber-like body and the other belt-like rubber-like body are vulcanized and bonded by a heating mold. When vulcanizing and molding the unvulcanized part of the end of the vulcanized belt-like rubber-like body and other belt-like rubber-like bodies, the heated mold has a part of the vulcanized lug and the drive projections. A part of it will again enter the heating mold and be positioned.
Finally, the end portions of the tensile body are overlapped with each other, and a belt-like rubber-like body is vulcanized and bonded to this portion, thereby forming an endless elastic crawler.
JP 2005-280337 A

For example, in the case of using a heat-shrinkable material such as nylon in addition to the steel cord as the tensile body, the tensile body contracts after vulcanization molding with a heating mold as described above. Therefore, the pitch of the vulcanized belt-like rubber-like body lugs may be reduced.
In the conventional elastic crawler manufacturing method, as described above, when vulcanized and bonded to the end of the vulcanized belt-like rubber-like body and the end of the unvulcanized rubber material, Some of the rubber-like lugs will enter the heated mold again, but the pitch of these lugs, etc. is reduced after vulcanization molding, so they will not fit well in the mold and are forced to pay. When vulcanized, an elastic crawler with a predetermined size may not be obtained.

  The present invention has been made in view of such circumstances, and provides an elastic crawler manufacturing method capable of manufacturing an elastic crawler having a desired size when a heat-shrinkable material is used as a tensile body. The purpose is to do.

In order to solve the above problems, the present invention has taken the following technical means.
That is, the present invention is an elastic crawler manufacturing method for forming an endless crawler body formed by vulcanizing a band-like rubber-like body on a heat-shrinkable tensile body. A first mold for vulcanization molding, and a second mold for adhering a band-like rubber-like body to an overlap portion in which ends of the tensile bodies are overlapped with each other. In the crawler body, lug forming recesses for forming lugs are formed at a predetermined pitch, and the second mold has a pitch smaller than the pitch of the lug forming recesses of the first mold. It is smaller than the pitch of the formed lug housing recesses, the lug forming recesses formed at a pitch equal to the pitch of the lug forming recesses of the first mold, and the lug forming recesses of the first mold. It is formed with a pitch and a lug is formed in the overlap portion. A second lug-forming recess is formed, and after the first band-like rubber-like body is vulcanized and molded into the tensile body with the first mold, the ends of the tensile body are overlapped with each other. In addition, a part of the rug of the vulcanized belt-like rubber-like body is stored in the lug housing recess of the second mold, and the belt-like rubber-like is formed on the overlap portion by the second lug forming recess of the second mold. The rug is formed by vulcanizing and bonding the body.

According to this, the first band-like rubber-like body vulcanized by the first mold is contracted by the tensile body after vulcanization, so that the pitch of the lug is the recess for forming the lug of the first mold. Smaller than the first pitch.
A part of the lug of the vulcanized belt-like rubber-like body will be accommodated in the lug accommodating recess of the second mold, but the lug accommodating recess is adapted to fit the reduced lug pitch. Since the pitch is smaller than the pitch of the recesses for forming the lugs of the first mold, the lugs will fit in the lug accommodating recesses without difficulty.

The overlapping portion at the end of the tensile body has a smaller amount of heat shrinkage after vulcanization than the non-overlapping portion. Therefore, it is necessary to make the pitch of the lug in the overlap portion after forming the elastic crawler equal to the pitch of the lug in the other portion.
By making the pitch of the second lug forming recesses for forming lugs in the overlap part smaller than the pitches of the lug forming recesses of the first mold, the pitch after the shrinkage of the lugs in the overlap part And the pitch after contraction of the lugs in other parts can be made substantially equal.
As described above, an elastic crawler having a desired dimension can be manufactured when a heat-shrinkable material is used for the tensile body.

  According to the present invention, an elastic crawler having a desired size can be manufactured when a heat-shrinkable material is used for the tensile body.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 3 illustrates an elastic crawler 1 manufactured by the elastic crawler manufacturing method according to the present invention. The elastic crawler 1 is used by being mounted on a traveling device such as an agricultural machine or a construction machine.
This traveling device is, for example, a sprocket, an idler, a plurality of wheels, and the like that are rotatably provided on a track frame. The elastic crawler 1 is wound around this traveling device and driven by the sprocket so as to travel. It has become.

The elastic crawler 1 includes an endless belt-like crawler body 2. A plurality of lugs 3 are formed on the outer peripheral surface 2 a of the crawler main body 2 at intervals in the circumferential direction of the crawler main body 2 (referred to as the belt longitudinal direction).
A plurality of drive protrusions 4 are formed on the inner peripheral surface 2b of the crawler body 2 to be driven by engaging the teeth of the sprocket. These drive protrusions 4 are formed at regular intervals in the circumferential direction of the crawler body 2. The drive protrusion 4 is formed at a position corresponding to the position of the lug 3.

An endless tensile body 5 is embedded in the crawler body 2. The tensile member 5 is made of a material having a higher shrinkage rate due to heat than a steel cord when vulcanized. Hereinafter, the property of the tensile body 5 is referred to as “heat shrinkability”. The tensile body 5 is made of a material having a large heat shrinkage, such as polyester or nylon.
A method for manufacturing the elastic crawler 1 will be described below.
The elastic crawler 1 is manufactured by vulcanizing and bonding the first rubber-like body 6 (6a) to the linear tensile body 5 by the first mold 8 shown in FIG. The end portions are overlapped with each other, and the band-like rubber-like body 6 (6b) is vulcanized and bonded by the second mold 22 around the overlapped portion. Each belt-like rubber-like body 6 (6a, 6b) is formed by integrally vulcanizing and molding a plurality of unvulcanized rubber materials 7.

A plurality of lug forming recesses 9 are formed in the first mold 8 so that the lugs 3 are formed on the elastic crawler 1. The lug forming recesses 9 are formed at a predetermined pitch P0 in the longitudinal direction of the first mold 8.
Further, the first mold 8 is formed with a plurality of drive projection forming recesses 10 so that the drive projections 4 are formed on the elastic crawler 1. The drive projection forming recesses 10 are formed at a predetermined pitch in the longitudinal direction of the first mold 8.
The driving projection forming recess 10 of the first mold 8 is provided corresponding to the position of the lug forming recess 9. The center of the driving projection forming recess 10 (the center line is indicated by symbol B in the figure) coincides with the center of the lug forming recess 9 (the center line is indicated by symbol A in the figure). Has been. Therefore, the pitch of the driving projection forming recesses 10 is equal to the pitch P0 of the lug forming recesses 9.

The first mold 8 includes a heating mold 12 for heating the unvulcanized rubber material 7 constituting the belt-like rubber-like body 6 and a cooling mold 13 provided at an end of the heating mold 12. . The heating mold 12 has an upper mold 12a and a lower mold 12b. A heating unit 14 is provided on the outer surfaces of the upper mold 12a and the lower mold 12b. The lug forming recesses 9 are formed at the pitch P0 in the upper mold 12a, and the drive projection forming recesses 10 are formed at the pitch P0 in the lower mold 12b.
The cooling mold 13 is vulcanized in order to bond the end of the vulcanized belt-like rubber-like body 6 vulcanized by the heating mold 12 and the end of another belt-like rubber-like body 6. The end portion of the belt-like rubber-like body 6 is cooled so as to remain in an unvulcanized or semi-vulcanized state.

The cooling mold 13 has a cooling passage through which cooling water passes. The cooling mold 13 is cooled to a temperature lower than that of the heating mold 12 by supplying cooling water having a constant temperature to the cooling passage by means of a cooling water supply device, so that the end of the belt-like rubber-like body 6 to be vulcanized is formed. Is supposed to cool.
The first belt-like rubber-like body 6a is sandwiched between the upper mold 12a and the lower mold 12b of the heating mold 12 with the heat-shrinkable tensile body 5 sandwiched between a plurality of unvulcanized rubber materials 7. The upper mold 12a and the lower mold 12b are heated by the heating unit 14 to be vulcanized into a predetermined shape.

A plurality of lugs 3 and drive protrusions 4 are formed on the vulcanized belt-like rubber-like body 6 (6a). The tensile body 5 is covered with an unvulcanized rubber layer 15 in advance. The rubber layer 15 is integrally formed with the belt-like rubber-like body 6 by the vulcanization molding.
The end in the longitudinal direction of the band-like rubber-like body 6a is cooled by the cooling mold 13 simultaneously with the heating by the heating mold 12, and when molding of the band-like rubber-like body 6a is finished, it is unvulcanized or semi-vulcanized. It becomes a state of sulfur.
After vulcanization molding of the first band-like rubber-like body 6 a by the first mold 8, the vulcanized band-like rubber-like body 6 a is removed from the first mold 8.

After performing the vulcanization molding by the first mold 8, as shown in FIG. 2, the ends of the tensile members 5 are overlapped with each other, and this overlap portion 31 (in the figure, the overlap portion is not overlapped). The endless elastic crawler 1 is formed by adhering the belt-like rubber-like body 6b.
The second mold 22 is used for this molding process. As shown in FIG. 2, the second mold 22 has a plurality of lug forming recesses 23 and a plurality of drive protrusion forming recesses 24, as in the first mold 8.

The lug forming recesses 23 are formed at a predetermined pitch P3 along the longitudinal direction of the second mold 22. The pitch P3 of the lug forming recesses 23 of the second mold 22 is equal to the pitch P0 of the lug forming recesses 9 of the first mold 8.
The drive projection forming recess 24 is formed at a position corresponding to the lug forming recess 23. The driving projection forming recess 24 is formed such that its center (the center line is indicated by a symbol H) coincides with the center of the lug forming recess 23 (the center line is indicated by a symbol G). Has been. The drive projection forming recesses 24 are formed at the same pitch P3 as the lug forming recesses 23.

The second mold 22 includes a lug 3 of the vulcanized belt-like rubber-like body 6, a lug accommodating recess 25 in which the driving projection 4 is accommodated, and a driving projection accommodating recess 26. The lug housing recesses 25 are formed at a predetermined pitch P1 in the longitudinal direction of the second mold 22. The pitch P <b> 1 of the lug accommodating recess 25 is smaller than the pitch P <b> 0 of the lug forming recess 9 of the first mold 8.
The drive projection receiving recess 26 is provided at a position corresponding to the lug receiving recess 25. In the longitudinal direction of the second mold 22, the center of the drive projection receiving recess 26 (the center line is indicated by the symbol J in the drawing) is the center of the lug receiving recess 25 (the center line is indicated by the symbol I in the drawing). Is shown).

The second mold 22 is formed with a plurality of second lug forming recesses 28 and a plurality of second drive protrusions in order to form the lugs 3 and the drive protrusions 4 in the overlap portion 31 at the end of the tensile body 5. A concave portion 29 is provided. The second lug forming recesses 28 are formed in the longitudinal direction of the second mold 22 at a predetermined pitch P2.
The second driving projection forming recess 29 is provided corresponding to the position of the second lug forming recess 28. The center of the second driving projection forming recess 29 (the center line is indicated by a symbol L in the drawing) coincides with the center of the second lug forming recess 28 (the center line is indicated by a symbol K in the drawing). ing. The pitch of the second drive projection forming recesses 29 is equal to the pitch P2 of the second lug forming recesses 28.

The pitch P2 of the second lug forming recesses 28 is set smaller than the pitch P3 of the lug forming recesses 23. That is, the pitch P <b> 2 of the second lug forming recess 28 is smaller than the pitch P <b> 0 of the lug forming recess 9 of the first mold 8.
The overlap portion 31 at the end of the tensile body 5 has a smaller shrinkage amount after vulcanization molding than the other portions. Therefore, when the overlap portion 31 contracts, the pitch P2 of the second lug forming recesses 28 is equal to the pitch P3 of the lug forming recesses 23 so that the pitches of the lugs 3 and drive protrusions 4 of the other portions are substantially equal. The pitch is smaller than the pitch P0 of the lug forming recesses 9 of the first mold 8.

The second mold 22 is divided into an upper mold 22a and a lower mold 22b. The upper mold 22a is formed with a lug forming recess 23, a lug receiving recess 25, and a second lug forming recess 28. The lower mold 22b is formed with a drive projection forming recess 24, a drive projection receiving recess 26, and a second drive projection forming recess 29. A heating unit 30 is provided on the outer surfaces of the upper mold 22a and the lower mold 22b.
The vulcanization molding process by the second mold 22 is performed as follows.
First, after the band-like rubber-like body 6 and the tensile body 5 are integrally vulcanized and molded by the first mold 8, the ends of the tensile body 5 are overlapped.

Then, the portion of the tensile body 5 to which the rubber-like body 6 is not bonded is sandwiched between a plurality of unvulcanized rubber materials 7, and these unvulcanized rubber materials 7 are connected to the upper mold 22 a of the second mold 22. The lug forming concave portion 23 and the second lug forming concave portion 28 are sandwiched between the driving protrusion forming concave portion 24 and the second driving protrusion forming concave portion 29 of the lower mold 22b.
At this time, the overlap portion 31 at the end of the tensile body 5 is provided with a portion where the second lug forming recess 28 of the upper die 22a is provided and a second drive projection forming recess 29 of the lower die 22b. It will be located between the parts.

Further, at this time, the lug 3 of the vulcanized belt-like rubber-like body 6 (6 a) enters the lug accommodating recess 25 of the second mold 22, and the driving projection 4 enters the driving projection accommodating recess 26. When this is done, each end in the longitudinal direction of the belt-like rubber-like body 6b vulcanized and molded by the second mold 22 is formed by the belt-like rubber-like body 6a vulcanized and molded by the first mold 8. It hits each end.
In this state, the belt-like rubber-like body 6b is vulcanized and heated by the heating part 30 of the upper die 22a and the lower die 22b. The end of the belt-like rubber-like body 6a vulcanized and molded by the first mold 8 is cooled by the cooling mold 13 and is in an unvulcanized or semi-vulcanized state. It is molded integrally with the end of the belt-like rubber-like body 6a by vulcanization molding.

As a result, the crawler main body 2 becomes endless, and the elastic crawler 1 in which the lugs 3 are formed on the outer peripheral surface 2a and the drive protrusions 4 are formed on the inner peripheral surface 2b is manufactured.
As described above, according to the method of manufacturing the elastic crawler 1 according to the present invention, when the heat-shrinkable tensile body 5 is used for the elastic crawler 1, the belt-like rubber-like body 6 is vulcanized to the tensile body 5. The tensile body 5 is shrunk by the heat at the time of molding, and as a result, the lugs 3 vulcanized and molded by the first mold 8 and the pitch of the drive projections 4 are the lug forming recesses 9 of the first mold 8. The pitch becomes smaller than the pitch P0 of the driving projection forming recesses 10.

The pitch P1 of the lug housing recess 25 of the second mold 22 and the drive projection housing recess 26 is set to be equal to the pitch of the lug forming recess 9 of the first mold 8 so as to be substantially equal to the pitch of the lugs 3 and drive projections 4. By setting the pitch smaller than the pitch P0, when the vulcanized and bonded unvulcanized rubber material 7 and one end portion of the belt-like rubber-like body 6 vulcanized by the first mold 8, the second gold The lug housing recess 25 and the drive projection housing recess 26 of the mold 22 can be accommodated without deforming the lug 3 and the drive projection 4 of the vulcanized belt-like rubber-like body 6.
Further, even when the belt-like rubber-like body 6b is vulcanized by the second mold 22, the pitch P3 of the lug forming recess 23 and the drive projection forming recess 24 of the second mold 22 is the 1 is equal to the pitch P0 of the lug forming recess 9 of the mold 8, and the lug 3 and the drive protrusion 4 formed by the lug forming recess 23 and the drive protrusion forming recess 24 are formed after the molding. Due to the contraction of the tension body 5, the pitch becomes smaller and becomes the same as the pitch of the already formed lugs 3 and drive protrusions 4.

  In addition, the lug 3 and the drive protrusion 4 formed by the second lug forming recess 28 and the second drive protrusion forming recess 29 also shrink the overlap portion 31 at the end of the tensile body 5 after molding. The pitch is smaller than the pitch P2 of the second lug forming recess 28 and the second drive projection forming recess 29, but considering the difference between the shrinkage amount of the overlap portion 31 and the shrinkage amount of the other portions, 2 The pitch P2 between the lug forming recess 28 and the second drive projection forming recess 29 is made smaller than the pitch P0 of the lug forming recess 9 of the first mold 8 by the difference in contraction amount. The pitch of the lug 3 and the driving projection 4 of the overlap portion 31 after contraction is equal to the pitch of the lug 3 and the driving projection 4 of the other portion.

As described above, the elastic crawler 1 has the lugs 3 and the drive protrusions 4 formed at an equal pitch, and can be manufactured to have a desired pitch dimension and circumference.
The method of the present invention can be applied as long as a rubber band is vulcanized and bonded to a heat-shrinkable tensile body, and is not limited to the above embodiment. Further, as the material of the tensile body, a heat-shrinkable material other than nylon or polyester may be used.

  The present invention can be used for manufacturing an elastic crawler.

It is sectional drawing which shows the 1st metal mold | die of embodiment which concerns on this invention. It is sectional drawing which shows the 2nd metal mold | die of embodiment which concerns on this invention. It is a side view which shows a part of elastic crawler manufactured by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic crawler 2 Crawler main body 3 Lug 5 Tensile body 8 1st metal mold | die 9 The recessed part 10 for the lug formation of the 1st metal mold | die 22 The 2nd metal mold 23 2nd metal mold | die 23 Lug forming recess 25 of second mold Lug housing recess 28 of second mold Second lug forming recess 31 of second mold Overlap portion

Claims (1)

A method for producing an elastic crawler that forms an endless crawler body formed by vulcanizing and forming a band-like rubber-like body on a heat-shrinkable tensile body,
A first mold for vulcanizing the first band-like rubber-like body, and a second mold for adhering the band-like rubber-like body to the overlapped portion where the ends of the tensile body overlap each other,
In the first mold, recesses for forming lugs for forming lugs on the crawler body are formed at a predetermined pitch,
The second mold has a lug housing recess formed at a pitch smaller than the pitch of the lug forming recess of the first mold and the pitch of the lug forming recess of the first mold. A lug forming recess formed at a pitch and a second lug forming recess formed at a pitch smaller than the pitch of the lug forming recess of the first mold to form a lug at the overlap portion And
After the first band-like rubber-like body is vulcanized and molded into the tensile body with the first mold, the ends of the tensile body are overlapped with each other and a part of the vulcanized belt-like rubber-like body In the lug housing recess of the second mold, and a rubber band is vulcanized and bonded to the overlap portion by the second lug forming recess of the second mold to form the lug. A method for producing an elastic crawler.

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