JP4282366B2 - Elastic crawler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elastic crawler used in various crawler type traveling devices.
[0002]
[Prior art]
Elastic crawler travel devices are widely used in agricultural machines such as combine harvesters and construction work machines such as backhoes. These agricultural machines and the like are equipped with an elastic crawler made of an endless rubber belt or the like. The elastic crawler has an endless belt-shaped crawler main body and a plurality of drive projections formed on the inner peripheral surface of the crawler main body. And a lug group formed on the outer peripheral surface with a predetermined lug pattern is used.
[0003]
Conventionally, a tensile body embedded in the crawler main body along the circumferential direction and a core metal embedded at a position corresponding to the lug in the crawler main body have been used. In high-speed crawler vehicles such as trucks and half-tracks, it is necessary to employ an elastic crawler having flexibility and light weight that enables high-speed rotation because the traveling speed is relatively high.
As such an elastic crawler having both flexibility and light weight, a coreless metal having no cored bar embedded in the crawler body is widely used (see Patent Document 1).
In the case of such a coreless crawler, the rubber gauge of the rubber elastic body is made thicker at the driving projection portion or the like instead of using the cored bar so as to obtain rigidity. In the molding of the coreless elastic crawler, the rubber vulcanizate is heated and vulcanized by a heated upper and lower mold to obtain a rubber elastic body.
[0004]
In addition, as a manufacturing method of the coreless elastic crawler, a rubber vulcanizate is placed between the upper and lower molds in order to improve durability without disturbing the steel cord in the crawler body. A production method is known in which a plate material is pre-pressed in a position where a steel cord is embedded, and then the plate material is removed, and a steel cord band is inserted into the air space formed here, followed by vulcanization molding ( Patent Document 2).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-129547 [Patent Document 2]
JP-A-8-52738 [Problem to be Solved by the Invention]
However, in the molding of the rubber elastic body that constitutes the above-described conventional coreless crawler as disclosed in Patent Document 1, the heat from the mold has a normal thickness to reach the inside of the relatively thick rubber gauge. Since a longer time than the part is required, it is necessary to set a longer vulcanization time by heating.
[0006]
However, in the vulcanization molding of thick rubber gauge parts, if the vulcanization time is shortened in accordance with the vulcanization time of the surface layer part, the degree of vulcanization inside the rubber away from the surface layer part will be insufficient, but it will be separated from the surface layer part. If the vulcanization time is lengthened in order to make the vulcanization degree inside the rubber sufficient, the vulcanization degree of the surface layer part will exceed the appropriate value, resulting in over cure, and a rubber elastic body with appropriate physical properties. There is a problem that makes it difficult to obtain.
This is caused by the fact that the temperature gradient from the surface layer to the inside of the rubber gauge is thick, rather than gradual, due to the low thermal conductivity of commonly used rubber vulcanizates. .
[0007]
This is conspicuous in a plurality of driving protrusions arranged at regular intervals on the inner peripheral surface of the elastic crawler and in a lug portion integrally formed with a predetermined lug pattern on the outer peripheral surface of the elastic crawler. This is not limited to a coreless elastic crawler, but may also occur in a lug portion of an elastic crawler provided with a cored bar.
Further, even if the elastic crawler is molded by a molding method as in Patent Document 2, it is inevitable that the rubber gauge becomes thick at the lug portion and the driving projection portion of the elastic crawler. Problems arising from low thermal conductivity remain.
In view of such circumstances, the present invention increases the thermal conductivity of the rubber vulcanizate forming the elastic crawler, thereby shortening the vulcanization time and reducing the cost, and the degree of vulcanization inside the rubber vulcanizate. It is an object of the present invention to provide an elastic crawler having improved wear resistance and cut resistance by reducing the difference between the degree of vulcanization and the degree of vulcanization of the surface layer portion to prevent overcuring of the surface layer portion.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention takes the following technical means.
That is, the present invention relates to a crawler body in which a plurality of drive protrusions arranged at regular intervals in the circumferential direction are formed on the inner peripheral surface, and a lug group integrally formed with a predetermined lug pattern on the outer peripheral surface of the crawler main body. In the elastic crawler formed from the rubber elastic body provided with an endless belt, a portion where the rubber gauge in the rubber elastic body is thickened is a normal rubber layer constituting the surface layer of this portion, and the rubber layer includes And a solid blended layer in which a material having higher thermal conductivity than the rubber elastic body is blended .
[0009]
In this case, the part where the rubber gauge is thickened in the rubber elastic body is blended with a normal rubber layer constituting the surface layer of this part and a material having higher thermal conductivity than the rubber elastic body included in the rubber layer. because it has a solid formulation layer, so that the thermal conductivity of the portion was thicker rubber gauge by high thermal conductivity material that is formulated containing layer of such solid increases.
As a result, during vulcanization molding, the heat of the heated mold is easily transferred to the inside of the thickened rubber gauge, and the molding material inside the part away from the mold surface can be used without taking a long vulcanization time. The degree of vulcanization can reach a predetermined state, and the vulcanization time can be shortened.
[0010]
On the other hand, the internal temperature of the part of the molding material where the rubber gauge is thickened can be raised at an early stage, and the difference in the degree of vulcanization is reduced by making the heating state of the part of the rubber gauge thicker and the surface layer the same. Thus, it is possible to prevent overcuring due to excessive vulcanization time of the surface layer portion due to excessive adjustment of the vulcanization time to the internal vulcanization degree as in the prior art, and excessive vulcanization of the surface layer portion .
Further, according to the present invention, the high the thermally conductive material, and that is embedded in the section position was thicker rubber gauge of the rubber elastic body. Thereby, since the internal thermal conductivity in the thick part of the rubber gauge is increased, vulcanization can be performed efficiently and the amount of the material having high thermal conductivity can be suppressed. In addition, the molding material can be made into a two-layer structure of a normal rubber layer and a compounding layer so that the portion in which the material having high thermal conductivity is embedded is included at a predetermined distance from the surface layer portion. .
[0011]
In addition, by making the rubber gauge thicker portions into the drive protrusions and / or lugs, materials with high thermal conductivity are embedded in these portions. It can be set to any value.
In the present invention, metal powder can be used as the material having excellent thermal conductivity. In this case, by using metal powder, it is easy to knead with the vulcanizate, and a molding material having very high thermal conductivity can be obtained. As the metal powder, various other metal powders such as copper, aluminum, iron, tungsten, magnesium, molybdenum, and nickel can be used.
[0012]
In the present invention, a metal fiber may be adopted as the material having excellent thermal conductivity. In this case, further excellent thermal conductivity can be obtained, and the rigidity of the entire elastic crawler can be increased by the reinforcing effect of the fibers, so that the wear resistance can be improved. Other metal fibers such as aluminum fibers and tungsten fibers can be used as the metal fibers.
Furthermore, in the present invention, carbon black may be employed as the material having excellent thermal conductivity. Thereby, the vulcanizate which has high heat conductivity can be obtained, and the intensity | strength of an elastic crawler can be raised. Further, the material can be easily kneaded into the vulcanizate, and an increase in weight can be suppressed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a coreless elastic crawler 1 according to the first embodiment of the present invention, and FIG. 2 shows a side view of a main part of a crawler traveling device 2 using the elastic crawler 1. As shown in FIG. 2, the crawler travel measure 2 of the present embodiment includes a sprocket 3 that is a driving wheel disposed at a predetermined position, an idler (not shown), and a plurality of wheels arranged between the idlers. The elastic crawler 1 is wound around these outer peripheries.
[0014]
As shown in FIG. 1, the elastic crawler 1 of the present embodiment includes a cored bar in which a plurality of drive protrusions 4 arranged at regular intervals in the circumferential direction (the arrow X direction in FIG. 2) are integrally projected from the inner peripheral surface. A crawler body 5 of a loess, a lug group composed of a large number of lug portions 6 formed in a predetermined lug pattern on the outer peripheral surface of the crawler body 5, and a resistance embedded in the crawler body 5 along the circumferential direction. A tension body 7 and a bias cord 8 embedded in the outer peripheral side of the tension body 7 inside the crawler body 5 are provided.
[0015]
Among these, the crawler main body 5 is formed in an endless belt shape having a substantially constant thickness by a rubber elastic body, and in the central portion of the crawler main body 5 in the width direction (the left-right direction in FIG. 1A), The drive protrusion 4 made of a rubber elastic body made of the same material as the crawler body 5 is provided so as to protrude. The drive protrusions 4 are provided over the entire circumference of the crawler body 5 at regular intervals in the circumferential direction, and the elastic crawler 1 is moved in the circumferential direction by engaging the sprockets 3 with the drive protrusions 4. Can be driven along.
[0016]
The sprocket 3 is configured by connecting a pair of left and right circular drive plates 13 with a plurality of drive pins (not shown) arranged at equal intervals in the circumferential direction, and each drive pin is a drive protrusion of the elastic crawler 1. The elastic crawler 1 is fed back and forth by rotating forward and backward while being caught by the portion 4.
The tensile body 7 is configured by juxtaposing tensile strength cords such as steel cords extending along the circumferential direction. On the other hand, the bias cord 8 is configured by arranging tensile strength cords such as steel cords in parallel in a direction inclined with respect to the circumferential direction. The bias cord 8 can also be provided on the inner peripheral side of the tensile body 7 and on both the inner peripheral side and the outer peripheral side.
[0017]
As shown in FIG. 1, the drive protrusion 4 and the lug 6 are thicker than other parts, and the normal rubber layer 9 and the metal powder contained therein are blended in such parts. A two-layer structure of the blending layer 10 is used.
The compounding layer 10 is provided at a predetermined distance from the surface layer of the driving protrusion 4 and the lug unit 6, and due to the effect of the high thermal conductivity of the metal powder, the thermal conductivity of the entire compounding layer 10 is normal rubber. It is higher than layer 9. Here, aluminum powder is used for the metal powder. Here, thermal conductivity represents the ease of heat transfer, and is the value obtained by dividing the amount of heat that flows per unit time through a unit area perpendicular to the heat flow by the temperature difference (temperature gradient) per unit length. This means that the larger the value, the easier the heat flows.
[0018]
Thus, by providing the compounding layer 10 in a thick portion of the rubber gauge such as the driving protrusion 4 and the lug 6, the heat of the mold is easily transferred from the surface layer portion to the inside during the heat forming, and from the surface layer portion to the inside. Therefore, the temperature inside the thick part can be raised at an early stage. Therefore, the degree of vulcanization at the site away from the mold can be reached to a predetermined state without taking a long time, and the time required for heating can be shortened. For this reason, power consumption etc. can be reduced and manufacturing cost can be held down.
Furthermore, since the internal temperature of the molding material can be raised at an early stage, the heating state between the inside of the molding material and the surface layer portion approaches, and the difference in the degree of vulcanization between the inside and the surface layer portion can be reduced. Conventionally, by adjusting the vulcanization time in order to reach a predetermined degree of vulcanization, the heating time becomes longer and the vulcanization degree of the surface layer portion becomes excessive. In this case, if the vulcanized product is excessively heated to overcure and the degree of vulcanization is excessive, the physical property value of the molded rubber elastic body cannot take a desired value, such as wear resistance and This was a cause of lowering the rigidity.
[0019]
On the other hand, in this embodiment, the vulcanization degree of the entire molding material can be made substantially uniform during vulcanization, so that overcuring of the surface layer portion can be prevented, and wear resistance and cut resistance are improved.
As the metal powder used here, copper, aluminum, iron, tungsten, magnesium, molybdenum, nickel, and other various metal powders can be used. Among these, copper powder with high thermal conductivity, aluminum powder, Stainless steel powder is preferably used. In addition to the metal powder, ceramics having high thermal conductivity can be used.
[0020]
By using a metal fiber in addition to the metal powder as a material having a high thermal conductivity to be blended in the blending layer 10, the wear resistance of the elastic crawler 1 can be obtained by providing a high thermal conductivity and simultaneously reinforcing the fiber. In addition, the rigidity can be increased. This is due to entanglement of metal fibers in the rubber elastic body constituting the matrix. As this metal fiber, a material similar to the metal powder such as copper and aluminum formed into a fiber shape is used, and a material formed to have a thickness of 20 μm to 150 μm and a length of 0.5 mm to 20 mm is preferably used. Is done.
Further, it is also possible to use carbon black as a material having high thermal conductivity to be blended in the blending layer 10. As the carbon black used here, high thermal conductivity can be expressed particularly by using a high-structure product having a DBP absorption amount of 135 ml / 100 g or more in which an aggregate has developed.
[0021]
In the present embodiment, a material having high thermal conductivity is blended only in the drive protrusion 4 and the lug 6 having a thick rubber gauge. However, by uniformly dispersing the rubber elastic body as a whole, the material is not limited to the thick and thin portions. The overall thermal conductivity of the molding material may be high and uniform. In this case, since the vulcanization molding time is shortened and only a single material needs to be molded, the manufacturing cost can be suppressed.
In addition, by exposing a highly heat conductive material to the surface layer of the rubber elastic body, the surface layer of the molding material may be in direct contact with the mold surface, thereby efficiently transferring heat from the contact portion to the inside. This makes it possible to perform vulcanization molding more efficiently.
[0022]
FIG. 3 shows an elastic crawler 1 according to the second embodiment of the present invention.
The difference between the elastic crawler 1 of this embodiment and that of the first embodiment is that the crawler main body 5 includes a metal core 11 that is long in the crawler width direction.
Here, the lug portion 6 having a thick rubber gauge is provided with a blending layer 10 in which aluminum powder is blended, and this portion has a two-layer structure of a normal rubber layer 9 and a blending layer 10. In the present embodiment, not limited to the metal powder, it is of course possible to use metal fibers or carbon black as in the first embodiment .
[0023]
In addition, this invention is not limited to the form of each above-mentioned Example.
For example, in order to increase the strength of the elastic crawler 1 according to the first embodiment, a reinforcing member made of hard resin or metal may be embedded in the drive protrusion 4. Moreover, the shape of the lug part 6 is good not only as what extended in the crawler width direction but incline in the crawler width direction. Furthermore, the material having high heat conductivity is not limited to the above-described materials, and is not limited to powder and fiber shape, and materials having other forms can be used.
[0024]
【The invention's effect】
As described above, according to the present invention, by increasing the thermal conductivity of the rubber vulcanizate forming the elastic crawler, the vulcanization time is shortened and the cost is reduced, and the vulcanization degree inside the vulcanizate is reduced. And the degree of vulcanization of the surface layer portion can be reduced to prevent overcuring of the surface layer portion and improve wear resistance and cut resistance.
[Brief description of the drawings]
1A is a cross-sectional view of an elastic crawler according to a first embodiment, and FIG. 1B is a longitudinal cross-sectional view of the crawler in the center in the width direction (a cross-sectional view taken along line AA in FIG. 1A). ).
FIG. 2 is a side view of a main part of a crawler type traveling device equipped with the elastic crawler of the first embodiment.
3A is a transverse sectional view of the elastic crawler of the second embodiment, and FIG. 3B is a longitudinal sectional view of the crawler in the center in the width direction (a sectional view taken along line BB in FIG. 2A). ).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Elastic crawler 4 Drive protrusion 5 Crawler main body 6 Lug part 9 Rubber layer 10 Compounding layer

Claims (5)

A rubber provided with a crawler body in which a plurality of drive protrusions arranged at regular intervals in the circumferential direction are formed on the inner peripheral surface, and a lug group integrally formed with a predetermined lug pattern on the outer peripheral surface of the crawler main body In an elastic crawler formed in an endless belt shape from an elastic body,
In the rubber elastic body, the portion where the rubber gauge is thick is blended with a normal rubber layer constituting the surface layer of this portion and a material having higher thermal conductivity than the rubber elastic body included in the rubber layer. An elastic crawler characterized by having a real blending layer . The elastic crawler according to claim 1 , wherein the rubber gauge is thickened at the drive protrusion and / or lug. The elastic crawler according to claim 1 or 2 , wherein the material having excellent thermal conductivity is metal powder. Elastic crawler according to claim 1 or 2, characterized in that the material is excellent in the heat conductivity is a metal fiber. Elastic crawler according to claim 1 or 2 material excellent in the heat conductivity, characterized in that a carbon black.

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