JP2008062830A - Rubber crawler and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a rubber crawler structure preventing breakage of various kinds of auxiliary cords embedded in a rubber crawler, particularly to provide a technology for preventing breakage of the auxiliary cords caused by rolling of a rolling wheel on the inner peripheral surface of a coreless rubber crawler. <P>SOLUTION: The rubber crawler comprises an endless rubber elastic body 1; main cords 2 embedded lined up in the longitudinal direction; a plurality of bias cords 3a, 3b embedded in relation to the main cords; or further 0° ply cords 4 embedded at a right angle to the embedded direction of the main cords 2; and a lug 6 formed at the outer peripheral surface, wherein the rolling wheel 10 rolls on the inner peripheral surface, and the thickness of rubber 9 between the main cords 2 and bias cords 3a, 3b and/or 0° ply cords 4 corresponding to the edge part 10a of the rolling wheel 10 is made thicker than rubber thickness between both of the cords at the other part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to the structure of a rubber track, and in particular, aims to improve the durability of a coreless rubber track.

  Hereinafter, the present invention will be described with a coreless rubber crawler. However, a steel cord is generally embedded in the endless rubber elastic body constituting the rubber crawler for the purpose of increasing the strength in the longitudinal direction and improving the bending rigidity. A steel cord (main cord), which is a tensile reinforcement material in the longitudinal direction, is embedded in the longitudinal direction. Bias code (two steel cords arranged at an inclination: first auxiliary cord) and, in some cases, a so-called 0 degree ply cord (steel cord extending in the width direction: second) extending at right angles to the main cord In general, the auxiliary code is embedded (Patent Document 1).

JP 2003-252259 A

  FIG. 1 is a view showing the structure of a conventional coreless-less rubber tracker, in which a rubber elastic body 1 constituting the rubber tracker is continuous on the front and back of the paper. And the main cord 2 with a large diameter excellent in strength is embedded in a row in the longitudinal direction. Two bias codes 3 (angle: about 35 degrees) are embedded on the outer peripheral side of the main code 1, and a 0-degree ply code 4 is embedded inside the main code 1. The bias code 3 and the 0 degree ply code 4 are steel codes having a slightly smaller diameter than the main code 1. In the drawing, a rubber protrusion 5 for driving is formed at a center of the inner peripheral surface of the rubber elastic body 1 with a constant pitch in the longitudinal direction, and a lug 6 is also formed on the outer peripheral surface of the rubber elastic body 1 with a constant pitch. Is formed.

  The rubber projection 5 is engaged with a sprocket (not shown) to transmit a driving force, and the left and right side surfaces 7 and 8 of the rubber projection 5 serve as running surfaces of the wheel 10.

  However, when the roller 10 passes through the inner peripheral surfaces 7 and 8 of the rubber crawler, the 0 degree ply cord 4 and the bias cord 3 are brought into contact with the contact edge 10a (especially the inner edge) of the roller 10 due to the load of the machine body. It may be bent repeatedly and cut due to fatigue. It has been pointed out that when the cords 3 and 4 are cut, they are peeled off from the rubber starting from the cut portions and eventually lead to the cutting of the main cord 1.

  The present invention proposes a rubber crawler structure that prevents the cutting of various auxiliary cords embedded in the rubber crawler. In particular, the inner ring of the coreless rubber crawler is provided with a roller. This is a technique for preventing the cutting of the auxiliary code that occurs when rolling.

  The first gist of the present invention is that an endless rubber elastic body constituting a rubber crawler, a main code embedded in a row in the longitudinal direction thereof, and a predetermined direction with respect to the embedding direction of the main code. A plurality of bias cords embedded at opposite angles, or a 0 degree ply cord embedded at a right angle to the direction in which the main code is embedded, and a lug formed on the outer peripheral surface A rubber crawler in which a wheel rolls on an inner peripheral surface, the main code and bias code of the rubber crawler corresponding to the edge of the wheel, and / or a 0 degree ply cord The rubber crawler is characterized in that the rubber thickness between the two is made thicker than the rubber thickness between the other parts.

  According to a second aspect of the present invention, there is provided a process for producing a rubber crawler according to the first aspect of the invention. The gist of the invention is a recess for forming a driving rubber projection at a predetermined position of a mold for molding a rubber crawler. Covered with a thin unvulcanized rubber sheet, a step of setting the unvulcanized rubber for the rubber protrusion, a step of placing an unvulcanized rubber sheet forming the inner peripheral side of the rubber crawler A step of placing a 0 degree ply cord, a step of stretching a main cord covered with a thin unvulcanized rubber sheet, a plurality of bias cords covered with a thin unvulcanized rubber sheet Are placed at a reverse angle, placed on an unvulcanized rubber sheet that forms the outer circumference of the rubber crawler, and each unvulcanized rubber is put under pressure in a rubber clast molding mold. A method of manufacturing a rubber crawler that is heated and integrally vulcanized, and includes right and left wheels of rubber protrusions. A rubber crawler characterized in that an unvulcanized rubber sheet is inserted between a main cord and a bias cord at a position opposite to the inner edge of a wheel at a portion to be a rolling surface and vulcanized. This unvulcanized rubber sheet has a higher hardness than the surrounding rubber material after vulcanization.

  In the first aspect of the present invention (Claim 1), the rubber amount corresponding to the auxiliary code of the part that is repeatedly bent (main code and auxiliary code) by interposing thick rubber at a specific part. The amount of rubber between the cords can be increased, and contact between the cords at the bent portion can be avoided, greatly reducing the breakage of the metal fibers that make up the auxiliary cord and greatly improving the durability of the crawler. It is possible to make it. In particular, in the case of a coreless rubber crawler (Claim 2), there are many problems due to the large number of auxiliary cords laminated, but the improvement in durability is remarkable by applying the present invention.

  According to a second aspect of the present invention (Claim 2), an unvulcanized rubber sheet having a higher hardness than the surrounding rubber material after vulcanization between a predetermined portion, that is, a main code and a bias code, at the time of manufacture. This is a method for producing a rubber crawler characterized by being vulcanized and inserted.

  Hereinafter, the first aspect of the present invention will be further described, and a rubber crawler structure for preventing cutting of various auxiliary cords embedded in the rubber crawler is proposed. This is a technique for preventing cutting of the auxiliary cord due to repeated distortion caused by the edge of the wheel when the wheel is rolled.

  In a general coreless rubber crawler, auxiliary cords such as a 0 degree ply cord and a bias cord are embedded in a main cord embedded in the longitudinal direction. The thickness of the rubber between the doors is constant over the entire width. The driving rubber protrusion engages with the sprocket to transmit the driving force, and the left and right side surfaces of the rubber protrusion are the running surfaces of the wheels. However, when the wheel passes through the inner peripheral surface of the rubber crawler, the 0 degree ply cord and the bias cord are repeatedly bent at the passing end of the wheel (the edge of the wheel) by the load of the machine body and cut by fatigue. Sometimes. In a general coreless rubber crawler, when the 0 degree ply cord and the auxiliary cord of the bias cord are cut, peeling from the rubber occurs starting from the cut portion. It will lead to disconnection.

  In the present invention, a rubber having a predetermined width is interposed at a predetermined portion between a plurality of auxiliary cords embedded in such a rubber crawler. The predetermined part is a part where the edge of the roller on the inner peripheral surface of the rubber crawler mainly contacts, and specifically, a part extending outward from the base of the driving rubber protrusion (repetitive bending in the laminated part) This is a region where The predetermined width is a range in which the possibility of bending at the predetermined portion is concerned.

  In the present invention, the rubber between the main cord and the auxiliary cord embedded in the coreless crawler is locally applied in the vicinity of the edge of the roller wheel that rolls on the inner peripheral surface of the rubber track. The thickness is increased to prevent the auxiliary cord from being cut. That is, a rubber sheet having a predetermined width is interposed between the laminated main cord and the auxiliary cord to prevent the laminated auxiliary cord (0 degree ply cord and bias cord) from being cut. The conventional drawbacks are solved by increasing the rigidity of the rubber. Accordingly, the rigidity of the thickened portion of the rubber is increased, and the bending due to the distortion of the 0 degree ply cord and the bias cord is not concentrated on the portion corresponding to the edge of the roller wheel contacting the inner peripheral surface of the rubber track. Therefore, it aims to make it difficult for cutting due to fatigue to occur. If the rubber is made thick evenly over the entire width instead of partially, there will be no difference in rigidity between the bent part and other parts, resulting in a state where stress concentration is not eliminated, and 0 degree ply code and bias cord Is less effective because it is concentrated on the edge of the wheel.

  The rubber crawler of the present invention may be a core crawler or a coreless rubber crawler (Claim 2), but is particularly effective in the latter case where the core metal is not embedded. In the latter case, the part where the thickness of the rubber is increased is a part (Claim 3) corresponding to the inner edge of the wheel that rolls with the rubber protrusion interposed therebetween. Also, it is preferable to use a rubber having a high hardness (Claim 4) to avoid concentration of bending of the auxiliary cord. By using hard rubber, the rigidity of the rubber near the bent portion can be improved, the repetition of excessive bending of the auxiliary cord can be reduced, and bending breakage can be eliminated.

  Such a thickened rubber portion preferably has a width of ± 5 to 20 mm from the inner edge of the wheel (Claim 5), and includes a base of the rubber protrusion and a width of 5 to 20 mm outward in the width direction (Claim 6). In addition, the rubber thick part is preferably 1 to 4 mm thicker than the other rubber parts (Claim 7).

  In the method of manufacturing a rubber crawler according to claim 8, which is the second invention, an unvulcanized rubber sheet that becomes harder than the rubber in other parts when laminated is laminated on the part. Thus, the rubber crawler according to claim 1 can be manufactured. Incidentally, in general rubber crawlers, rubber with a rubber hardness of about 60 degrees (JIS A) is adopted, but the rubber hardness of the laminated portion of the present invention is preferably higher than this, For example, rubber of about 65 to 90 degrees, preferably about 70 to 85 degrees is preferable.

  The main code and various auxiliary codes are used in a state where they are covered with a thin unvulcanized rubber sheet (triat rubber) at the time of molding. Those having higher hardness than rubber are preferred, and more specifically, it is possible to replace the trit rubber itself with the rubber of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to examples. FIG. 2 is a cross-sectional view of the coreless rubber crawler of the first invention. Reference numerals 1 to 8 and 10 are the same as those shown in FIG. 1, and a detailed description is omitted here. However, the thickness of the main code (steel code) 2 is 3.5 mm, and other auxiliary codes. The thickness of the cords (steel cords) 3 and 4 was 1 mm. In addition, each auxiliary code used was covered with a treat rubber, but including these, the layer of the main code 2 was 5 mm, and the layers of the other auxiliary codes 3 and 4 were 2 mm. .

  Now, rubber 9 (hardness 80 degrees) having a slightly higher hardness than the surrounding rubber (hardness 65 degrees) is inserted between the main code 2 (layer) and the bias code 3 (layer). . The rubber 9 is embedded with a width W of 20 mm from the slightly inner side of the base portion 5a of the rubber protrusion 5 to the outer side in the width direction. The rubber thickness T is 2 mm. This portion is a portion that rolls while the inner edge portion 10a of the roller wheel 10 is in contact with it, and the auxiliary cord 3 that has repeatedly been subjected to bending strain is supported by the presence of the rubber layer 9. The movement of the code (especially the bias code 3) is restricted, the rubber is not cracked, and the auxiliary code 3 is not cut.

  In the above example, the rubber layer 9 has a substantially trapezoidal cross section. However, it is needless to say that the rubber layer 9 is not limited to such a shape, and may be, for example, an arcuate cross section.

  FIG. 3 is a cross-sectional view showing another embodiment. In this example, a rubber layer 9 is inserted between two bias codes 3a and 3b.

  FIG. 4 is a sectional view showing still another embodiment. In this example, a rubber layer 9 is interposed between the main cord 2 and the O-degree ply cord 4. As a result, cutting of the 0-degree ply code 4 can be prevented.

  Although not shown, the combination of the rubber layers 9 in FIGS. 2 to 4 can be freely combined. By adopting any combination of these rubber layers, the size of the rubber crawler and its intended use can be determined. Thus, the auxiliary cord cutting phenomenon caused by the above can be effectively prevented.

  FIG. 5 is a conceptual diagram showing the manufacturing method of the rubber crawler shown in FIG. 2, that is, the second invention. The mold defining the inner peripheral surface of the rubber crawler is the lower mold 20A, and the rubber crawler A mold that divides the outer peripheral surface is defined as an upper mold 20B. The lower mold 20A is provided with a recess 21 for forming a driving rubber projection, while the upper mold 20B is provided with a recess 22 for forming a lug.

  In the manufacturing process, first, a semi-cured projection preform 11 formed in advance in the recess 21 is embedded, and then an unvulcanized rubber sheet 12 for forming the inner peripheral surface of the rubber crawler, A 0 degree ply cord 4 covered with a vulcanized coated rubber and a main code 2 covered with an unvulcanized coated rubber are laminated. Then, an unvulcanized rubber sheet 9A having a width of 20 mm and a thickness of 2 mm is laminated so as to slightly straddle the embedded projection preform 1. Further, the bias codes 3a and 3b, which are also covered with the coated rubber, are stacked at different angles at different angles. An unvulcanized rubber sheet 13 that forms the outer peripheral side of the rubber crawler is laminated thereon, and if necessary, an unvulcanized rubber 14 for rugs is embedded in the recess 22 and fixed to a certain degree. A rubber crawler is obtained by heating and vulcanization under pressure.

  The present invention is as described above, and is particularly effective in preventing the cutting of the auxiliary cord of the coreless rubber crawler, and greatly contributes to the improvement of the life of the rubber crawler. It can also be used for a rubber crawler with a cored bar.

FIG. 1 is a view of a conventional mandrel-less rubber crawler. FIG. 2 is a cross-sectional view of the coreless rubber rubber tracker of the first invention. FIG. 3 is a cross-sectional view of a coreless rubber crawler showing another example of the first invention. FIG. 4 is a sectional view of a coreless rubber crawler showing still another example of the first invention. FIG. 5 is a diagram showing the manufacture of the coreless rubber rubber tracker of the second invention.

Explanation of symbols

1. Rubber elastic body,
2. Main code,
3, 3a, 3b ... Bias code,
4 ... 0 degree ply code,
5. Rubber protrusion for driving,
6 ... lag,
7, 8 ... Rolling wheel running surface,
9 ... rubber layer,
9A: Unvulcanized rubber sheet,
10. Rolling wheel
10a ... the edge of the wheel,
11 ... rubber protrusion preform,
12. An unvulcanized rubber sheet that forms the inner peripheral surface of the rubber track,
13. Unvulcanized rubber sheet that forms the outer peripheral surface of the rubber crawler,
14 ... unvulcanized rubber forming the lug,
20A, 20B Mold,
21 .. depression for rubber protrusion,
22 ... Dug for rug.

Claims (8)

  An endless rubber elastic body constituting a rubber crawler, a main cord embedded in a row in the longitudinal direction thereof, and a plurality of embedded at a predetermined opposing angle with respect to the embedding direction of the main cord A bias cord of one sheet, or a 0 degree ply cord embedded at a right angle to the embedding direction of the main cord, and a lug formed on the outer peripheral surface, on the inner peripheral surface A rubber crawler on which the wheel rolls, and the rubber thickness between the main cord of the rubber crawler corresponding to the edge of the wheel and the bias code and / or the 0 degree ply cord, A rubber crawler characterized by being thicker than the rubber thickness between the other parts.   2. A rubber crawler according to claim 1, wherein rubber protrusions meshing with the sprocket are formed at a constant pitch on the inner peripheral surface of the rubber elastic body, and both left and right sides of the rubber protrusion are used as running surfaces of the wheel.   The rubber crawler according to claim 1 or 2, wherein the rubber thickness at a portion corresponding to the inner edge of the roller wheel that rolls with the rubber protrusion interposed therebetween is thicker than the rubber thickness at other portions.   The rubber crawler according to any one of claims 1 to 3, wherein the rubber at a portion where the rubber thickness is increased is made of rubber having a higher hardness than rubber at other portions.   The rubber crawler according to any one of claims 1 to 4, wherein the portion where the rubber thickness is increased has a width of ± 5 to 20 mm from an inner edge of the wheel.   The rubber crawler according to any one of claims 1 to 5, wherein the portion where the rubber thickness is increased has a width of 5 to 20 mm in a width direction including a base portion of the rubber protrusion.   The rubber crawler according to any one of claims 1 to 6, wherein the rubber thick portion is 1 to 4 mm thicker than the other rubber portions.   A step of setting an unvulcanized rubber for the rubber protrusion in a recess for forming a rubber protrusion for driving at a predetermined position of a mold for molding a rubber crawler; an unvulcanized rubber sheet for forming an inner peripheral side of the rubber crawler A step of placing a sheet, a step of placing a 0 degree ply cord covered with a thin unvulcanized rubber sheet, and a main cord covered with a thin unvulcanized rubber sheet. A step, a step of placing a plurality of bias cords covered with a thin unvulcanized rubber sheet at an opposite angle, a step of placing an unvulcanized rubber sheet forming the outer peripheral side of the rubber crawler, This is a rubber crawler manufacturing method in which each unvulcanized rubber is heated under pressure in a rubber crawler molding mold and integrally vulcanized and molded. Between the main code and the bias code at a position facing the inner edge of the wheel at the part that becomes the surface, Rubber material high hardness become unvulcanized Gomushi than - Insert the door, characterized in that the vulcanized Gomukuro - la production methods.

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