JP2516423B2 - Conveyor belt - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a conveyor belt wound between pulleys, and more particularly to a conveyor belt having a structure in which a heat resistant or impact resistant reinforcing layer is embedded.

[Prior Art] A conveyor belt is endlessly wound between pulleys arranged at a predetermined interval, and carries an object to be conveyed by placing an object to be conveyed on its conveying surface. As this conveyor belt, as shown in FIG. 2, a structure in which a tensile strength layer 81 is embedded in a rubber belt main body 80 along its length is known. The tensile body layer 81 ensures tensile strength in the length direction of the conveyor belt between the pulleys R, and is usually formed by laminating canvases in the thickness direction.

Further, as a conveyor belt, as shown in FIG. 3, there is also known a structure in which a reinforcing layer 86 is embedded in the rubber belt main body 80 along the length direction thereof in addition to the tensile body layer 81. The reinforcing layer 86 protects the conveyor belt from the impact and heat of the transported object. The reinforcing layer 86 having such a protective function is located closer to the conveyor surface of the conveyor belt than the tensile body layer 81.

[Problems to be Solved by the Invention]

By the way, when the conveyor belt is reversed by the pulley R, in the conveyor belt in which the tensile body layer 81 shown in FIG. 2 is embedded, the tensile body layer 81 is a neutral area which is a boundary region between a tension state and a compression state. It becomes a point. Therefore, a compressive force acts on the lower cover rubber layer 82 inside the tensile body layer 81, and a tensile force acts on the upper cover rubber layer 83 outside the tensile body layer 81. Here, it is the rubber that forms the lower cover rubber layer 82 and the upper cover rubber layer 83, and since the rubber has excellent followability to compression and tension, the tensile body layer 81 is not fatigued except in extreme cases. No destruction occurs.

Further, as shown in FIG. 3, in addition to the tensile body layer 81, the reinforcing layer 86.
In the conveyor belt in which is embedded, the neutral point, which is the boundary area between the tension state and the compression state, shifts to the transport surface 80a side. The reason is that the conventional reinforcing layer 86 uses the aramid fiber layer having a high elastic modulus as it is. Therefore, in the conveyor belt shown in FIG. 3, when the conveyor belt is bent by the pulley R, a compressive force acts on the tensile body layer 81 inside the reinforcing layer 86, and therefore the tensile body layer 81 buckles. Occurs. Since this buckling repeatedly acts every time the conveyor belt is bent by the pulley, the tensile body layer 81 is buckled and fatigued, and the strength gradually decreases, and finally the tensile body layer 81 is cut.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to avoid buckling of a tensile body layer that has conventionally occurred, to improve the problem of cutting the tensile body layer and improve durability. Another object of the present invention is to provide a conveyor belt that can ensure heat resistance and impact resistance of the conveyor belt to such an extent that there is no practical problem.

[Means for Solving the Problems] The conveyor belt of the present invention is a long sheet-shaped rubber belt main body, and is continuously embedded in the rubber belt main body along the length direction thereof, and has a predetermined elastic modulus in the length direction. And the tensile body layer, which is located closer to the conveying surface than the tensile body layer and is continuously embedded in the rubber belt main body along the length direction thereof, and has an elastic modulus in the longitudinal direction higher than that of the tensile body layer. It is characterized by comprising a reinforcing layer knitted with a low warp yarn and a weft yarn having heat resistance and impact resistance.

The tensile body layer ensures the tensile strength of the conveyor belt between the pulleys, and can be formed by laminating an appropriate number of canvases in the thickness direction as in the conventional case.

The reinforcing layer is located closer to the conveying surface than the tensile body layer and is continuously embedded in the rubber belt main body along the length direction thereof. The reinforcing layer is formed by knitting warp yarns extending in the length direction of the conveyor belt and weft yarns extending in the width direction of the conveyor belt. The warp yarns are set so that the elastic modulus in the length direction of the conveyor belt is lower than the elastic modulus in the length direction of the tensile body layer. In the case of nylon fiber, the elastic modulus in the length direction of the warp yarn can be 100 to 3100 kg / cm · ply by appropriately selecting the thickness of the yarn, the number of twists per m of the yarn, and the method of heat treatment. Here, [kg / cm · ply] means that in a belt with a core made of canvas, etc., the tensile force applied to 1 sheet (that is, 1 ply) per 1 cm of the core width and parallel to this pulling It means Young's modulus, which indicates the ratio to elongation. Specifically, using a test piece of 100 mm width x 1000 mm length, first apply a load of 25% of the breaking strength of the test piece, then load up to 5%. Decrease, then increase load to 20% of breaking strength, decrease to 5% again, and apply load of 20% of breaking strength again. In the belt industry, since the cross-sectional area of the yarn is difficult to measure, the standard is 1 cm instead of 1 cm, and the unit of kg / cm · ply is adopted. Note that kg
/ cm · ply may be abbreviated as kg / c · p.

In the conveyor belt of the present invention, as the warp threads forming the reinforcing layer, synthetic fibers, natural fibers and the like can be adopted, and for example,
Nylon fiber, polyester fiber, vinylon fiber, acrylic fiber, polyolefin fiber, etc. can be adopted.

The weft thread forming the reinforcing layer is a thread having heat resistance and impact resistance, and improves heat resistance and impact resistance on the conveying surface side of the conveyor belt. As the weft, for example,
In some cases, metal fibers or carbon fibers such as aramid fiber and glass fiber can be adopted.

[Operation] The operation of the conveyor belt of the present invention will be described together with its usage. This conveyor belt is used by being wound between pulleys in the same manner as in the past, and when the pulleys are driven, the conveyor belt travels and conveys the conveyed object with the conveyed object placed on the conveying surface.

A tensile force acts on the conveyor belt between the pulleys.
At this time, the tensile member layer functions to secure the tensile strength of the conveyor belt. Therefore, when the conveyor belt is bent by the pulley, the portion of the tensile body layer becomes a neutral point which is a boundary region between the tension state and the compression state. Therefore, a tensile force acts on the conveying surface side of the tensile body layer, and a compressive force acts on the inner side of the tensile body layer.

[Example] An example of the conveyor belt of the present invention will be described below.

A cross-sectional view of the conveyor belt of this embodiment is shown in FIG. As shown in FIG. 1, a conveyor belt comprises an endless rubber belt body 1 and a tensile body layer 2 embedded in the rubber belt body 1 in an endless manner along the length direction thereof.
And a reinforcing layer 3 embedded in the rubber belt body 1 in an endless manner along the length direction thereof.

The rubber belt body 1 is formed of upper cover rubber layers 10 and 11 and a lower cover rubber layer 12. Upper cover rubber layer 10,
11. The lower cover rubber layer 12 has a longitudinal elastic modulus of about 40 kg / cm. Here, the longitudinal elastic modulus means the elastic modulus in the length direction of the conveyor belt.

The tensile body layer 2 is formed by laminating five layers in the thickness direction of plain weave canvas in which warp yarns made of polyester and weft yarns made of nylon are knitted in a cloth shape. The longitudinal elastic modulus of the tensile body layer 2 is
It is about 1500 kg / cm · ply. The strength of each piece of canvas forming the tensile body layer 2 is about 115 to 119 kg / cm · ply.

The reinforcing layer 3 protects the conveyor belt from the impact when the transported object is transported and the heat of the transported object, and is located closer to the transport surface 1a side on which the transported object is placed than the tensile body layer 2. It is located and buried endlessly. The reinforcing layer 3 has a warp and a weft knitted in a plain weave. This warp is made from nylon fiber with a denier of approximately 1260 and has a longitudinal elastic modulus.
It is about 250 kg / cm · ply. This weft is made of aramid fiber with a denier of about 1000 and has heat resistance and impact resistance, and secures the dent resistance of the conveyor belt.

When using this conveyor belt, it is used by being wound endlessly between a drive pulley and a driven pulley as in the conventional case. Then, the drive pulley is driven to convey the conveyed object placed on the conveying surface of the conveyor belt.

When the conveyor belt is running between the drive pulley and the driven pulley, a tensile force acts on the conveyor belt between the drive pulley and the driven pulley as in the conventional case.
At this time, in this embodiment, the longitudinal elastic modulus of the reinforcing layer 3 in the longitudinal direction is set lower than the longitudinal elastic modulus of the tensile body layer 2, so that the longitudinal elastic modulus of the tensile body layer 2 is reinforced eventually. It has been made higher than the longitudinal elastic modulus of the layer 3, and therefore the tensile layer 2
Serves to secure the tensile strength of the conveyor belt between the drive pulley and the driven pulley. Therefore, in this embodiment, the tensile body layer 2 is formed while the conveyor belt is running.
The part of has tensile strength.

Therefore, in this embodiment, when the conveyor belt is bent by the pulleys, it is the boundary area between the tension state and the compression state as in the conveyor belt in which only the tensile body layer 81 shown in FIG. 2 is embedded. The tensile body layer 2 is located at the neutral point.
Therefore, it is possible to avoid buckling of the tensile body layer 2, and even when the number of times of bending by the pulley is dramatically increased due to the long period of use, the tensile body layer 2 is prevented. Buckling fatigue can be avoided.

In addition, when the conveyor belt is bent by the pulley, the pressure distribution in the cross section is as described above, the tensile strength layer 2
Has a tensile property, a tensile force acts on the conveying surface side, that is, the upper cover rubber layer 10 and the upper cover rubber layer 11 with respect to the tensile body layer 2, and the inner side of the tensile body layer 2, that is, the lower cover rubber layer. A compressive force acts on 12.

By the way, in this embodiment having a structure in which the warp threads of the reinforcing layer 3 are made of nylon, the heat resistance and the impact resistance of the reinforcing layer 3 may decrease. In this respect, in this embodiment, since the weft yarns forming the reinforcing layer 3 together with the warp yarns are made of aramid fiber having heat resistance and impact resistance, the reinforcement layer 3 itself, and by extension, the heat resistance and impact resistance of the conveyor belt are practically used. It can be secured to the extent that there is no hindrance, so the conveyor belt is less susceptible to the heat and impact of the transported object.

[Test Example] Using the conveyor belt of this example, a running test and a Scott test were performed as a dynamic test, the conveyor belt was bent with a pulley a predetermined number of times, and after that test, the appearance of the conveyor belt was inspected and further tested. Five sailcloths forming the stretch layer 2 (each sailcloth 1p in order from the transport surface 1a side,
2p, 3p, 4p, 5p) were removed from the conveyor belt and each fabric was tested for tensile strength.

In the running test, as shown in FIG. 4, a conveyor belt was wound around a driving pulley 50 and three driven pulleys 51, 52 and 53. Drive pulley 50, driven pulleys 51, 52, 53
The pulley diameter is 500 mm, the belt speed is 290 m / min, and the number of flexing is 2.15 million times.

In the Scott test, as shown in Fig. 5, the driven pulley
A conveyor belt was installed on 56 and reciprocated in the length direction with a stroke of 300 mm. The driven pulley 56 has a pulley diameter of 200 mm and the number of times of bending is 1.7 million.

Furthermore, as a comparative example, the conveyor belts A, B, and C having the structure in which both the tensile body layer 81 and the reinforcing layer 86 shown in FIG. Tests and Scott tests were conducted. In the conveyor belts A, B, and C according to the comparative example, the reinforcing layer 86 is formed by knitting a warp yarn made of aramid fiber and a weft yarn made of polyester, and its longitudinal elastic modulus is 12200 kg / cm · ply, and tensile strength is The body layer 81 is formed by laminating five layers of canvas knitting a warp yarn made of polyester and a weft yarn made of nylon, and its longitudinal elastic modulus is 1500 kg / cm · ply.

The results of the above-mentioned running test are shown in Table 1. As shown in Table 1, the appearance of the conveyor belt of this example was examined after the running test, and it was found that there was no cut damage and no particular abnormality. Further, in the conveyor belt of this embodiment, as shown in Table 1, the strength of 1 P of the canvas of the tensile body layer 2 is 114 kg / cm · pl.
y, 2P strength of tensile body layer 2 is 114kg / cm · ply, tensile body layer 2
The strength of 3P is 113kg / cm · ply, and the strength of 4P of the tensile body layer 2 is 1
16kg / cm ・ ply, 5P strength of the tensile body layer 2 is 119kg / cm ・ ply
Met. In addition, in the conveyor belt of this example, when each canvas of the tensile body layer 2 was examined, there was no abnormality in 1P to 5P.

On the other hand, in the comparative example, the conveyor belt A,
In both B and C, a crack of about 20 cm was found in the lower cover rubber layer 82, and a buckling trace was found in each canvas of the tensile body layer 81. Further, in the conveyor belt A of the comparative example, each of the canvases of the tensile body layer 81 has a cut damage of 3P to 5P, and in the conveyor belt B of the comparative example, a cut wound of the canvas of the tensile body layer 81 is cut. Was occurring.

Further, in the comparative example, as shown in Table 1, the tensile body layer 81
The strength of 1P is 20kg / cm · ply for conveyor belt A, 72kg / cm · ply for conveyor belt B, and 83 for conveyor belt C.
kg / cm · ply. The 2P strength of the tensile body layer 81 is 29 kg / cm · ply for conveyor belt A and 54 kg / c for conveyor belt B.
m · ply, conveyor belt C: 47 kg / cm · ply. The 3P strength of the tensile body layer 81 is 24kg / cm · p for the conveyor belt A.
ly, the conveyor belt B has 49 kg / cm · ply, and the conveyor belt C has 46 kg / cm · ply. The tensile strength of 4P of the tensile body layer 81 is 18 kg / cm · ply for conveyor belt A and conveyor belt B.
35 kg / cm ・ ply for conveyor belt 42.5 kg / cm ・ p for conveyor belt C
ly. The 5P strength of the tensile body layer 81 is 14 kg / cm · ply for the conveyor belt A and 43 kg / cm · ply for the conveyor belt B.
The conveyor belt C had a weight of 38 kg / cm · ply. Further, buckling scratches were found on the conveyor belts A, B, and C of the comparative example. Further, with conveyor belt A, there was a 5 mm cut on 3P and 4P, and a 10 mm cut on 5P.

The results of the above Scott test are shown in Table 2. Second
As shown in the table, when the appearance of the conveyor belt of this example was examined, there was no evidence of buckling, and there was no particular abnormality. The tensile strength of 1P of the tensile body layer 2 is 119kg / cm · ply, the strength of 2P of the tensile body layer 2 is 112kg / cm · ply, 3P of the tensile body layer 2
Has a strength of 109 kg / cm · ply, and the tensile strength of the 4P layer 2 is 109 kg.
/ cm · ply, the strength of 5P of the tensile body layer 2 is 111kg / cm On the other hand, in the conveyor belt of the comparative example, in appearance, no crack was found in the lower cover rubber layer 82, but buckling marks were found in each canvas of the tensile body layer 81. Also, as shown in Table 2, the tensile strength of the tensile layer 81 is 37 kg / cm · ply, and the tensile strength of the tensile layer 81 at 2P is 40 kg / cm · ply. The strength of 3P of 81 is 38 kg / cm · ply, and the tensile strength of 81
The strength of 4P is 41kg / cmply, and the strength of 5P of the tensile body layer 81 is 38kg.
It was / cm · ply. Further, buckling damage was found on each canvas of the tensile body layer 81.

As is clear from the test results shown in Tables 1 and 2 above, in the conveyor belt of this example after the test, the strength of each canvas forming the tensile body layer 2 was 109 to 119 kg.
/ cm · ply. Here, since the strength of each canvas forming the tensile body layer 2 before the test is 115 to 119 kg / cm · ply as described above, the strength of the canvas does not decrease even if the above running test and Scott test are performed. rare.

However, in the case of the comparative example, the strength of each canvas forming the tensile body 81 is 20 to 83 kg / cm · ply. Therefore, the reduction in strength of each canvas of the conveyor belt according to the comparative example is extremely large. Therefore, in the conveyor belt of this embodiment, the tensile body layer 2 is used.
It can be seen that it is extremely advantageous in preventing buckling fatigue.

[Advantages of the Invention] In the conveyor belt of the present invention, as described above, since the longitudinal elastic modulus of the warp forming the reinforcing layer is lower than that of the tensile body layer, buckling occurs in the tensile body layer. This can be avoided as much as possible. Therefore, even when the number of times of bending by the pulley increases drastically over a long period of use, it is possible to avoid buckling fatigue in the tensile body layer as much as possible, and it is possible to extend the life of the conveyor belt.

Furthermore, in the conveyor belt of the present invention, since the weft yarns having heat resistance and impact resistance are knitted in the reinforcing layer, the reinforcing layer itself, and by extension, the heat resistance and impact resistance of the conveyor belt can be practically impaired. Therefore, the conveyor belt is unlikely to be affected by heat and impact from the transported object.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conveyor belt. FIG. 2 is a partial cross-sectional view of a conventional conveyor belt wound around a pulley. FIG. 3 is a partial cross-sectional view showing a state in which a conventional conveyor belt having a reinforcing layer embedded therein is wound around a pulley. FIG. 4 is a block diagram showing the principle of the running test, and FIG. 5 is a block diagram showing the principle of the Scott test. In the figure, 1 is a rubber belt main body, 2 is a tensile body layer, and 3 is a reinforcing layer.

Claims (1)

(57) [Claims] 1. A rubber sheet main body in the form of a long sheet, a tensile body layer which is continuously embedded in the rubber belt main body along the lengthwise direction thereof and has a predetermined elastic modulus in the lengthwise direction. A warp yarn that is located closer to the conveyance surface than the body layer and is continuously embedded in the rubber belt main body along the length direction thereof, and has a modulus of elasticity in the length direction lower than that of the tensile body layer and heat resistance and resistance. A conveyor belt, comprising a weft yarn having impact properties and a reinforcing layer knitted with the weft yarn.