JP2014034196A - Production method of elastic crawler and vulcanization molding mold for elastic crawler production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of an elastic crawler in which a crack hardly occurs in a rolling wheel travel part, and even when a crack occurs, the crack hardly grows; a vulcanization molding mold that is used for production of the elastic crawler.SOLUTION: A production method of an elastic crawler of the present invention relates to a production method in which a continuous molding part is newly vulcanization molded at an end on one side in a belt longer direction of a vulcanization molded one part, thereby a belt-like elastic crawler having an end before endpoint connection is produced. In the production method, in vulcanization molding of a part that continues to one part that is vulcanization molded, a vulcanization part H in which vulcanization molding of an unvulcanized rubber is accelerated by heat from a heat mold 2 having heat means 11, and a suppression part in which vulcanization of the unvulcanized rubber is suppressed by a cooling mold 3 having cooling means 16 connected to an end on one side in a belt longer direction of the heat mold, are formed. In addition, a part excluding an end of a direction corresponding to a crosswise direction of the elastic crawler in the suppression part is projected to a heat mold side.

Description

  The present invention relates to a method for producing an elastic crawler to be mounted on a self-propelled crawler type traveling device in a farm work device, a construction work device, and the like, and a vulcanization mold used for the production of the elastic crawler.

Elastic crawlers mounted on civil engineering work machines, construction work machines used in residential land development, road construction, river maintenance, etc., or self-propelled crawler type traveling devices used in agricultural work are formed in an endless belt shape. ing.
One method for producing such an endless belt-like elastic crawler is feed vulcanization in which a vulcanization mold is used and vulcanization molding is performed for each part. The production of elastic crawlers by feed vulcanization is, for example, vulcanization molding of only a part of a long strip of rubber embedded with a tensile body by sandwiching it with a mold from both sides in the thickness direction. This operation is repeated by feeding the belt-like rubber one after another, and finally, the both ends left uncured are overlapped, sandwiched between molds, vulcanized and joined (Patent Document) 1).

In addition to the heating zone for heating, the mold used for the production of elastic crawlers by feed vulcanization has to be added at both ends in order to obtain good (physical) continuity with the next vulcanization molding part. A cooling zone for cooling to suppress sulfur is provided.
Conventionally, the production of the elastic crawler is performed in the cooling zone 83 as shown in the cross-sectional view taken along the line B-B in FIG. 5A (plan view) of the vulcanization mold 8 (of the lower mold 81). In many cases, the upper die 82 and the lower die 81 having end faces 84 and 85 of 90 degrees with respect to the feeding direction (band longitudinal direction) are used. The elastic crawler manufactured with such a vulcanization mold 8 is partially vulcanized at the joining portion 83a in the cooling zone 83 where unvulcanized is desirable. As a result, the vulcanization molded portion in the next feed vulcanization and In the vicinity of the boundary, the bonding strength becomes weak. The elastic crawler manufactured with the vulcanization mold 8 is prone to cracks due to repeatedly applied tensile load from the drive wheel, bending load when passing through the drive wheel, etc., and the crack is tensile in a relatively short time. There was a problem of reaching the body 86.

  Therefore, in order to keep the joint portion with the next vulcanization molded portion in the unvulcanized state in the feed vulcanization, the vulcanization having a tapered shape by inclining the end face of the cooling zone where the belt-like rubber joint portion is formed. A molding die was employed (Patent Document 1, FIG. 5).

JP 2002-120231 A

  By the way, in recent years, demands regarding the durability of elastic crawlers have become stricter. There is an increasing tendency to thicken the rubber of the wheel running part that supports the wheel. When the rubber of the wheel running portion becomes thicker, the length of the unvulcanized portion for joining is limited, so the taper angle becomes large and the joined portion becomes insufficient in strength against bending load. There is a problem that cracks cannot be sufficiently prevented from being generated in the ring-passing portion, and the generated cracks grow quickly.

  The present invention has been made in view of the above-described problems, and is a method of manufacturing an elastic crawler that hardly causes cracks in a wheel running portion and that does not easily grow even if cracks occur, and vulcanization molding used in the manufacture of elastic crawlers. The purpose is to provide molds.

In the elastic crawler manufacturing method according to the present invention, the end-banded elastic crawler before connection at both ends is formed by newly vulcanizing a molded part continuous to one end in the longitudinal direction of the part of the vulcanized part. The present invention relates to a manufacturing method for manufacturing.
This manufacturing method includes a vulcanization part for accelerating vulcanization molding of unvulcanized rubber by heating from a heating mold having a heating means in a vulcanization molding of a part continuing to a vulcanized part, and a heating mold. And a restraining portion in which vulcanization of unvulcanized rubber is restrained by a cooling mold having a cooling means connected to one end in the longitudinal direction of the belt. And a part except the end of the direction corresponding to the width direction of the elastic crawler in the suppression part is made to protrude to the heating die side.

Preferably, the thickness corresponding to the thickness direction of the elastic crawler of the restraining portion is gradually increased from the cooling mold side toward the heating mold side.
The vulcanization mold according to the present invention is a vulcanization molding of a part of the vulcanized part that is continuous with one end in the longitudinal direction of the band to vulcanize and manufacture an end-banded elastic crawler before connecting both ends. This is a vulcanization mold.

The vulcanization mold has a heating means that promotes vulcanization molding of unvulcanized rubber and a cooling means that is connected to one end of the heating mold to suppress vulcanization of unvulcanized rubber. A cooling mold. A part of the cooling mold, excluding an end in a direction corresponding to the width direction of the elastic crawler, at the end connected to the heating mold protrudes into the heating mold.
Preferably, in the cooling mold, the thickness corresponding to the thickness direction of the elastic crawler in the space containing unvulcanized rubber that suppresses vulcanization gradually increases as it goes from the cooling mold side to the heating mold side. Formed as follows.

  According to the present invention, it is possible to provide a method for manufacturing an elastic crawler that hardly causes cracks in a wheel running portion and that does not easily grow even if cracks occur, and a vulcanization mold used for manufacturing the elastic crawler.

FIG. 1 is a plan view of a vulcanization mold that forms the inner peripheral surface of an elastic crawler. 2 is a cross-sectional view of the vulcanization mold taken along the line AA in FIG. FIG. 3 is a diagram showing a manufacturing process of an elastic crawler using a vulcanization mold. FIG. 4 is a diagram illustrating the inclination angles of the upper tapered portion and the lower tapered portion. FIG. 5 is a diagram showing an outline of a conventional vulcanization mold.

FIG. 1 is a plan view of a vulcanization mold that forms the inner peripheral surface side of the elastic crawler, and FIG. 2 is a cross-sectional view of the vulcanization mold taken along line AA in FIG.
The vulcanization mold 1 used for the production of the elastic crawler includes a heating mold 2 that performs vulcanization molding by heating, heating sections 11 and 11 for heating the heating mold 2, and unvulcanized during vulcanization molding. It is composed of a cooling mold 3 or the like for leaving a sulfur portion.

  The heating mold 2 is formed by sandwiching unstretched rubber around a specific length of a long band-shaped tensile body 21 formed of a plurality of steel cords from both sides in the thickness direction of the tensile body 21. By heating and vulcanization molding, a part of the elastic crawler in the longitudinal direction is formed. The heating mold 2 includes an upper die 4 having a surface (referred to as an “upper mold surface 12”) having a concavo-convex relationship with the outer peripheral shape of the rubber portion of the elastic crawler, and a surface having a concavo-convex relationship with the inner peripheral shape (“ And a lower mold 5 having a lower mold surface 13).

  The upper mold surface 12 is provided with a lug forming part 121 for forming an elastic crawler lug. The lower mold surface 13 is provided with a pair of projection forming portions 131 and 131 arranged in the width direction at regular intervals, which are depressions that form projections projecting to the inner peripheral surface of the elastic crawler. In the lower mold 5 for the elastic crawler having a cored bar, a recess for accommodating the protruding portion toward the inner peripheral side of the cored bar is provided in place of the projection forming portions 131 and 131.

Here, the “longitudinal direction” is the longitudinal direction of the tensile body 21 sandwiched between the heating molds 2 and is the longitudinal direction of the elastic crawler partially formed after vulcanization molding. The “width direction” is the vertical direction of FIG. 1, that is, the width direction of the tensile body 21 sandwiched between the heating molds 2. The same applies to the following description.
The lower mold surface 13 has wheel running surface forming portions 132 and 132 that are flat surfaces extending in the longitudinal direction on both sides in the width direction of the projection forming portion 131. The wheel running surface forming portion 132 is deeper than the lower die surface 13 on the outer side in the width direction so that the wheel running portion in the elastic crawler after vulcanization is thickened.

The heating units 11 are provided in contact with the outer surfaces of the upper mold 4 and the lower mold 5 opposite to the upper mold surface 12 and the lower mold surface 13, respectively. The heating unit 11 uses the electric heater as a heating source and heats the upper mold 4 and the lower mold 5 to a set temperature under the control of the controller. The heating units 11 and 11 may be incorporated in the upper mold 4 and the lower mold 5 without being separated from the upper mold 4 and the lower mold 5.
The cooling mold 3 is connected to both ends of the heating mold 2 in the longitudinal direction. The cooling mold 3 provided at one end in the longitudinal direction is for leaving an unvulcanized portion, which is a connecting portion with the next vulcanized portion in the feed vulcanization, in a specific shape. In the first feed vulcanization, the cooling mold on the other side in the longitudinal direction is for connecting the unvulcanized portion on the side where the feed vulcanization is finished to the end opposite to the side where the feed vulcanization is sequentially advanced. Used to leave the unvulcanized part of. The cooling mold on the other side is removed after the first vulcanization molding.

The range (cooling range) occupied by the cooling mold 3 for leaving an unvulcanized or semi-vulcanized portion in the vulcanization mold 1 is a range C in FIG. In addition, the range (heating range) of the heating mold 2 for performing vulcanization molding is a range H in FIG.
The cooling mold 3 includes a cooling upper mold 6 connected to the end in the longitudinal direction of the upper mold 4 of the vulcanization mold 1 and a cooling lower mold 7 connected to the end in the longitudinal direction of the lower mold 5.

With reference to FIG. 1, the cooling lower mold | type 7 is demonstrated.
The cooling lower mold 7 has a lower tapered portion 15 that accommodates a portion where vulcanization is prevented during vulcanization molding. The lower taper portion 15 starts from the end edge 133 at the connecting portion of the lower mold surface 13 (of the lower mold 5), and approaches the cooling upper mold 6 as the distance from the end 133 increases. Formed as. The lower taper portion 15 is a concave portion having a wedge-shaped cross section extending in the width direction. The cooling lower mold 7 has an inner side in the width direction at the end face connected to the heating mold 2 (lower mold 5) protruding toward the heating mold 2 (lower mold 5). The range of protrusion of the lower cooling mold 7 toward the heating mold 2 (size in the width direction, WD in FIG. 1) includes a range (WR in FIG. 1) including at least the wheel running surface forming portions 132 and 132. The width WC of the lower mold surface 13 in the lower mold 5 forming the main part of the elastic crawler is smaller (the width of the upper surface 12 of the upper mold 4 is also the same dimension (WC)). 1 and 2, reference numeral 134 denotes an end surface of a portion (hereinafter referred to as “protruding portion 135”) that protrudes toward the heating mold 2 in the cooling lower die 7, and reference numeral 136 denotes a portion that does not protrude (hereinafter referred to as “non-projecting portion 137”). ).

The “range of protrusion toward the heating mold 2” is based on the boundary (position S in FIG. 1) between the protrusion 135 and the non-protrusion 137 at the outer side in the width direction.
The cooling upper die 6 also starts from the edge 123 at the connecting portion of the upper surface 12 (of the upper die 4) as in the cooling lower die 7, and approaches the cooling lower die 7 as the distance from the edge 123 increases. The upper tapered portion 14 is formed with the plane inclined as a surface. The upper tapered portion 14 is a concave portion having a wedge-shaped cross section extending in the width direction. The cooling upper mold 6 excludes the inner projecting portion 125 in the width direction in which the end face connected to the heating mold 2 (upper mold 4) projects to the heating mold 2 (upper mold 4) side, and this. An unprojected portion 127 that does not project toward the heating mold 2 (upper mold 4) is provided.

  The range in the width direction of the protrusion 125 in the cooling upper mold 6 is a range that coincides with the protrusion 135 of the cooling lower mold 7 when the cooling upper mold 6 is superimposed on the cooling lower mold 7. It is the range that overlaps. In FIGS. 1 and 2, reference numeral 124 is an end face of the protruding portion 125 on the heating mold 2 (upper mold 4) side, and reference numeral 126 is an end face of the non-projecting portion 127 on the heating mold 2 (upper mold 4) side.

“A part of the cooling upper mold 6 and the cooling lower mold 7 protrudes toward the heating mold 2” means that the cooling upper mold 6 and the cooling lower mold are within the range (heating range H) occupied by the heating mold 2 in the longitudinal direction. It means that a part of the mold 7 overlaps and overlaps. This overlapping range (overlapping range) is indicated by D in FIGS.
In the vulcanization mold 1, as shown in FIG. 1, the protrusion 135 of the cooling lower mold 7 is interrupted at the center in the width direction. However, if the center in the width direction of the produced elastic crawler has a thickness sufficient to provide the protruding portion 135, the protruding degree of the end surface is aligned with the end surfaces 134 of the protruding portions 135 on both sides in the width direction, and is continued. Alternatively, even if it is difficult to align the end face of the central portion in the width direction with the end face 134, it is possible to reduce the degree of protrusion from both sides in the width direction and continue in the width direction as a whole according to the thickness of the center in the width direction. it can.

The shape of the protruding portion 125 and the central portion in the width direction of the upper cooling mold 6 is also designed according to the shape of the central portion in the width direction of the elastic crawler similarly to the lower cooling mold 7.
The cooling mold 3 is provided with flow paths 16 and 16 through which cooling water and the like flow.
FIG. 3 is a diagram showing a process of manufacturing an elastic crawler using the vulcanization mold 1.
First, unvulcanized rubber forming an inner peripheral elastic crawler body portion is packed on the lower mold surface 13 of the lower mold 5, and one end side (the right side in FIG. 3A) is placed on the cooling metal. The tensile body 21 is placed so as to protrude outward from the mold 3b and the longitudinal direction thereof is aligned with the longitudinal direction of the lower mold 5. Next, unvulcanized rubber forming a lug or the like is disposed so as to surround the tensile body 21, and these are accommodated in the upper mold 4 and the lower mold 5. The cooling lower mold 7 and the cooling upper mold 6 are respectively connected to both sides of the heating mold 2 in the longitudinal direction, and unvulcanized rubber is filled between them.

The heating mold 2 is heated to the vulcanization temperature by the heating units 11 and 11, the unvulcanized rubber in the heating mold 2 is vulcanized, and cooled to the flow paths 16,..., 16 of the cooling molds 3a and 3b. The medium is sent to suppress vulcanization of the unvulcanized rubber in the cooling molds 3a and 3b (FIG. 3 (a)).
When the vulcanization molding process is completed, the vulcanization mold 1 is opened, and the formed elastic crawler part 22 is a vulcanization mold leaving a part including the unvulcanized rubber part 23 in the cooling mold 3a. 1 (FIG. 3B).

The unvulcanized rubber is filled around the tensile body 21 that has moved into the vulcanization mold 1 from the outside, the vulcanization mold 1 is closed, and the tensile body 21 in the vulcanization mold 1 is closed. A vulcanization molding process similar to the first vulcanization molding process is performed on the unvulcanized rubber 24 surrounding the rubber.
When this vulcanization molding process is completed, the vulcanization mold 1 is opened, and the formed elastic crawler part is sent out of the vulcanization mold 1 leaving a part including the unvulcanized rubber part 25. The unvulcanized rubber is filled around the tensile body 21 newly moved into the vulcanization mold 1 and vulcanization molding processing is performed.

These processes are repeated to form a belt-like elastic crawler in which the tensile body 21 is buried except for the vicinity of both ends thereof. Finally, in the vicinity of both ends of the belt-like elastic crawler, exposed tensile bodies are overlapped and unvulcanized rubber is arranged around them, and is accommodated in the vulcanization mold 1 and vulcanized in the same manner as described above. An endless belt-like elastic crawler is manufactured by forming.
The vulcanization mold 1 has a part of the cooling mold 3 protruding toward the heating mold 2 (protruding portions 125 and 135), and joined to a portion formed by the next vulcanization molding by this structure. The progress of vulcanization of the portion to be left as unvulcanized (unvulcanized rubber portion 25) can be effectively suppressed.

  In the vulcanization molding process, for example, when the vulcanization of the unvulcanized rubber part for joining proceeds in the vulcanization molding die, the unvulcanized rubber part for joining in the next vulcanization molding process in the feed vulcanization is performed. In addition, sufficient strength (adhesive strength) cannot be obtained for joining with an unvulcanized rubber that is newly vulcanized and molded. For example, in a vulcanization molding die that does not have the protrusions 125 and 135, such as the vulcanization molding die 1, the heat transfer area between the cooling mold and the unvulcanized rubber is small, so that the unvulcanized for joining The cooling of the rubber part is not always sufficient.

  On the other hand, the vulcanization mold 1 is provided with the protrusions 125 and 135 on the cooling mold 3, so that, for example, on one side in the width direction of the cooling lower mold 7, the points P to P in FIG. The heat transfer area in the range surrounded by S increases. The vulcanization molding die 1 increases the heat transfer area with the unvulcanized rubber portion for joining in the cooling die 3, thereby improving the cooling capacity for this portion and effectively suppressing the progress of vulcanization. As a result, the vulcanization molding die 1 can produce an elastic crawler which can perform the joining of the vulcanized molding parts divided into several times with sufficient strength, and is less prone to cracks in the wheel running parts. can do.

  In order to obtain such an effect in the vulcanization mold 1, the projecting portions 125 and 135 are not provided in the entire width direction of the cooling mold 3 (the cooling upper mold 6 and the cooling lower mold 7), but in the width direction. It needs to be part. When the protrusions 125 and 135 are provided in the entire width direction of the cooling mold 3, the portions to be left unvulcanized (unvulcanized rubber portions 23 and 25) are excessively cooled, and in the mold release operation after vulcanization molding This part sticks to the vulcanization mold 1 and makes it difficult to release. With an elastic crawler that embeds the core metal, in addition to the difficulty in releasing, the rubber in the vicinity of this part peels off from the core metal during the release process. It becomes easy to do.

  Further, since the vulcanization molding die 1 is provided with projections 125 and 135 at least in a range (rolling wheel running surface forming portions 132 and 132) which becomes a rolling wheel running surface in the elastic crawler, The tapered portion 14 and the lower tapered portion 15 can be elongated in the longitudinal direction. Therefore, when manufacturing an elastic crawler having a large rubber thickness at the wheel running portion, the upper taper portion 94 and the lower taper portion 95 (FIG. 4 ( Compared to (a), the inclination angles of the upper tapered portion 14 and the lower tapered portion 15 can be made gentle (β <α, η <γ, see FIG. 4B). Therefore, the elastic crawler manufactured by the vulcanization molding die 1 is relieved of stress caused by repeated bending when passing through the drive wheel of the crawler type traveling device, and is not easily cracked. It is hard to do.

  The distance WD between the outer ends on both sides in the width direction of the protrusions 125 and 135 in the cooling mold 3 is equal to or greater than the distance WR between the outer ends on both sides in the width direction of the wheel running surface forming portions 132 and 132 in the lower mold 5. . The protrusions 125 and 135 include the wheel running surface forming portions 132 and 132 between both ends in the width direction, and when WD = WR, the width between both ends in the wheel running surface forming portion. 132 and 132 are provided so as to coincide with both ends in the width direction.

The distance WD between the outer ends on both sides in the width direction of the protrusions 125 and 135 is preferably WD ≦ 0.88WC, based on the width WC of the lower mold surface 13 that forms the main part of the elastic crawler in the lower mold 5. WD ≦ 0.75WC is more preferable.
A range D (see FIG. 1) in which part of the cooling upper mold 6 and the cooling lower mold 7 protrudes toward the heating mold 2 varies depending on the size of the elastic crawler, but usually a size of about 10 mm is adopted. .

In the conventional vulcanization mold 8 shown in FIG. 5, the cooling upper mold 87 and the cooling lower mold 88 are each provided with a protruding portion that protrudes toward the heating mold (upper mold 82, lower mold 81), thereby cooling. Vulcanization of the joint portion 83a joined to the next vulcanization molding portion in the zone 83 can be suppressed (see FIG. 5).
In the above-mentioned embodiment, each structure of the vulcanization mold 1 and the vulcanization mold 1 or the overall structure, shape, dimensions, number, material, and the like can be appropriately changed in accordance with the spirit of the present invention. it can.

  INDUSTRIAL APPLICABILITY The present invention can be used for manufacturing an elastic crawler that is attached to a self-propelled crawler-type traveling device in a farm work device, a construction work device, or the like.

1 Vulcanization mold 2 Heating mold 3 Cooling mold 11 Heating part (heating means)
16 Channel (for cooling) (cooling means)
H Heating range (heating part)

Claims (4)

A manufacturing method for manufacturing an end-banded elastic crawler before connecting both ends by newly vulcanizing a molded part that is continuous with an end portion on one side in the longitudinal direction of a part of the vulcanized part,
In vulcanization molding of the continuous molded part,
A vulcanized portion that promotes vulcanization molding of unvulcanized rubber by heating from a heating mold having a heating means;
Forming a suppression portion in which vulcanization of unvulcanized rubber is suppressed by a cooling mold having a cooling means connected to one end of the heating mold in the longitudinal direction of the band,
A part of the restraining portion excluding an end in a direction corresponding to the width direction of the elastic crawler is protruded toward the heating mold. The method of manufacturing an elastic crawler according to claim 1, wherein a thickness corresponding to a thickness direction of the elastic crawler of the suppression portion is gradually increased from the cooling mold side toward the heating mold side. A vulcanization mold for producing an end-banded elastic crawler before connecting both ends by newly vulcanizing and molding a molded part continuous to one end of the vulcanized part in the longitudinal direction of the band,
A heating mold that has a heating means and promotes vulcanization molding of unvulcanized rubber;
A cooling mold that includes cooling means and is connected to one end of the heating mold to suppress vulcanization of unvulcanized rubber,
A part of the cooling mold except for an end in a direction corresponding to the width direction of the elastic crawler at an end connected to the heating mold protrudes into the heating mold. Sulfur molding mold. In the cooling mold, the thickness corresponding to the thickness direction of the elastic crawler in the space containing unvulcanized rubber that suppresses vulcanization gradually increases as it goes from the cooling mold side to the heating mold side. The vulcanization mold according to claim 3, which is formed as follows.