JP5018005B2 - Conveyor belt for shot blasting equipment - Google Patents

Description

  The present invention relates to a conveyor belt for a shot blasting apparatus, and more particularly to a conveyor belt for a shot blasting apparatus having excellent buckling resistance even when the number of canvas layers is large.

  2. Description of the Related Art A so-called apron type shot blasting apparatus is known that projects a projection material while rotating and agitating a workpiece such as a metal part on a conveying surface of a conveyor belt (for example, a patent) Reference 1). In order to ensure compactness, such a shot blasting device has a small diameter pulley for stretching the conveyor belt, and in order to ensure the tensile strength of the endless portion of the conveyor belt (joint portion at both ends in the longitudinal direction of the canvas layer). The number of laminated layers of the canvas layer serving as the core material is, for example, 6 or more and more than a general conveyor belt.

Therefore, when the conveyor belt operates and passes around the pulley and bends, a very large compressive stress is generated each time the canvas layer is bent from the neutral surface. The warp yarn which comprises may be buckled by compression stress and may break. If you continue to operate the conveyor belt while the warp is buckled, it will cause a problem that the canvas layer will be damaged due to major damage to the canvas layer, so use a core material with excellent buckling resistance. It was necessary to construct a conveyor belt.
JP-A-6-000769

  An object of the present invention is to provide a conveyor belt for a shot blasting device having excellent buckling resistance even when the number of canvas layers is large.

In order to achieve the above object, the conveyor belt for the shot blasting apparatus of the present invention is constructed by laminating a plurality of plain weave canvas layers as the core material embedded between the upper and lower rubber layers, and the belt width direction on the conveying surface For a shot blasting apparatus in which a rotating plate is provided opposite to the container , and the object to be polished is rotated and stirred in a storage portion formed by the opposing rotating plate and a conveying surface bent along the outer periphery of the rotating plate . Conveyor belt, among the plurality of canvas layers, at least for the canvas layer laminated on the innermost peripheral side of the conveyor belt, the gauge thickness H of the canvas layer after molding and vulcanization, The warp crimp ratio C calculated by the following formula (1) with the gauge thickness h and the weft arrangement pitch P is 3.6% or more, and the total value K of the warp and weft cover factors K of the canvas layer is 4300 or more. 55 0 is characterized in the following as the fact.
C = (((H−h) ² + P ² ) ^1/2 / P−1) × 100 (%) (1)

  According to the conveyor belt for the shot blasting apparatus of the present invention, the innermost side of the neutral surface where the greatest compressive stress is generated when the conveyor belt is operated and repeatedly passes through the pulleys and bends repeatedly. For the canvas layer laminated on the circumferential side, the warp yarn between the arrangement pitches P of the weft yarn is set to 3.6% or more by the warp crimp ratio C calculated by the above formula (1) after molding and vulcanization of the conveyor belt. The curvature of the woven structure is increased. Thereby, the compressive stress which arises in the warp by bending can be disperse | distributed, and generation | occurrence | production of buckling can be prevented.

  In addition, the total value K of the warp and weft cover factors of the canvas layer laminated on the innermost circumferential side is set to 4300 to 5500, and the degree of clogging of the warp and weft is set. Thereby, shrinkage of the canvas layer due to heating during manufacture of the conveyor belt can be suppressed and a large degree of warp bending can be maintained, so that the buckling resistance of the conveyor belt can be improved.

  Hereinafter, a conveyor belt for a shot blasting apparatus according to the present invention will be described based on the embodiments shown in the drawings.

  As illustrated in FIG. 1, a conveyor belt 1 for shot blasting apparatus of the present invention (hereinafter referred to as a conveyor belt 1) is mounted on a so-called apron type shot blasting apparatus 6. The shot blasting device 6 includes rotating plates 8 and 8 facing in the width direction on the conveying surface of the conveyor belt 1 between a pulley 7d at a front position and a pulley 7c at an upper position. A space surrounded by the rotating plates 8 and 8 and the conveying surface of the conveyor belt 1 serves as the accommodating portion 11 for the workpiece 12. A projection device 9 for projecting the projection material 10 is disposed above the housing portion 11.

  Since the shot blasting device 6 is configured in a compact manner, the diameters of a large number of pulleys 7a to 7e that span the conveyor belt 1 are configured to be small and are arranged in a limited space. It is stretched so as to sew on the pulleys 7a to 7e. The conveyor belt 1 is attached and detached when the pulley 7a at the lower position moves up and down, and is stretched with a necessary tension by adjusting the amount of movement of the pulley 7a.

  As illustrated in FIG. 2, this conveyor belt 1 has a core material 3 interposed between rubber layers 2 and 2, and the core material 3 is formed by laminating eight layers of canvas layers 3a to 3h having the same specifications of a plain weave structure. It is configured. The number of layers of the canvas layers 3a to 3h is determined by the required performance (rigidity, elongation, etc.) for the conveyor belt 1 and is not limited to 8 layers, but in order not to make the bending rigidity too high, for example, 6 layers About 10 to 10 layers, more preferably about 7 to 8 layers.

  Further, in order to obtain sufficient tensile strength of the conveyor belt 1, it is particularly preferable that the longitudinal direction breaking strength of each of the canvas layers 3a to 3h is 1000 N / cm or more and 1500 N / cm or less, but it is laminated at least on the innermost side. The longitudinal rupture strength of the canvas layers 3a and 3h may be 1000 N / cm or more and 1500 N / cm or less. When the longitudinal breaking strength exceeds 1500 N / cm, the bending rigidity increases, and the bending resistance of the conveyor belt 1 tends to be adversely affected. The longitudinal breaking strength is a value measured based on JIS K 6322.

  In order to treat the surface of the workpiece 12, the drive pulley 7b is rotationally driven to operate the conveyor belt 1, and the rotary plates 8 and 8 are also rotated together with this. Thus, the surface of the workpiece 12 is polished evenly by rotating and stirring the workpiece 12 accommodated, and simultaneously projecting the projection material 10 from the projection device 9 and continuing this machining operation for a predetermined time. Is done.

  During this processing operation, the conveyor belt 1 passes around the respective pulleys 7a to 7e and is repeatedly bent each time. As illustrated in FIG. 3, the conveyor belt 1 that rotates around the pulley 7 a and the other pulleys 7 b to 7 e has a neutral surface N indicated by a two-dot chain line as a boundary. Tensile stress is generated, and compressive stress is generated on the inner peripheral side. FIG. 3 is simplified for ease of explanation, and the canvas layers 3b, 3c, 3f, and 3g are omitted.

  The position of the neutral plane N varies depending on the thickness of the conveyor belt 1 and the number and position of the canvas layers 3a to 3h. For example, compressive stress is generated in the canvas layers 3a to 3d on the inner peripheral side, If the canvas layers 3a to 3h have the same specifications, the greatest compressive stress is generated in the canvas layer 3a on the innermost side. The warp yarn 4 and the weft yarn 5 constituting the canvas layers 3a to 3h have a certain degree of rigidity against tensile stress but are extremely low against compression stress.

  As illustrated in FIG. 4, the canvas layer 3 a having a plain weave structure has a woven structure in which the warp yarn 4 and the weft yarn 5 float and sink one by one, and the warp yarn 4 moves up and down between the arrangement pitches P of the weft yarn 5. The weft 5 is also curved up and down between the arrangement pitches of the warps 4. Since all eight canvas layers 3a to 3h have the same specifications, FIG. 4 shows the canvas layer 3a as a representative.

  The warp yarn 4 extends in the longitudinal direction of the conveyor belt 1 and the weft yarn 5 extends in the width direction of the conveyor belt 1, so that even if the conveyor belt 1 is bent around the pulleys 7 a to 7 e, Almost no compressive stress is generated, but a large compressive stress is generated in the warp 4.

  Therefore, for the canvas layers 3a to 3d that are repeatedly bent and generate compressive stress each time the conveyor belt 1 is operated and passes around the pulleys 7a to 7e, the warp yarn 4 is not buckled by the bending, and the canvas layer It is necessary to prevent breakage of the warp 4 which develops into a large damage of 3a to 3d. In particular, it is necessary to prevent the warp 4 from buckling in the canvas layer 3a laminated on the innermost peripheral side where the greatest compressive stress is generated.

  The bending condition of the woven structure of the warp yarn 4 greatly affects the occurrence of buckling due to bending. If the bending condition is small and intersects linearly with the weft thread 5, it cannot be easily deformed. Compressive stress concentrates and bends, causing buckling. On the other hand, if the warp 4 is a woven structure that is greatly curved in the vertical direction, it can be easily deformed over a wide range, so that the risk of buckling due to dispersion of compressive stress is reduced.

  Therefore, in the present invention, as shown in FIG. 4, the length of the warp yarn 4 between the arrangement pitch P of the weft yarn 5 and the arrangement pitch P of the weft yarn 5 of the canvas layers 3 a to 3 h after molding and vulcanization of the conveyor belt 1. Based on the ratio to L, the degree of bending of the woven structure of the warp yarn 4 is defined. That is, it can be said that as the L / P value is larger, the warp 4 is more curved and less buckled.

Strictly speaking, the length L of the warp yarns 4 between the arrangement pitches P of the weft yarns 5 is not a straight line as shown by a two-dot chain line in FIG. 4, but is a curve along the curved shape of the warp yarns 4. The length L of the warp 4 can be easily calculated by approximating it as a dotted chain line. For example, as shown in FIG. 4, the length of the hypotenuse of a right triangle is obtained by using the arrangement pitch P of the weft 5, the gauge thickness H of the canvas layers 3 a to 3 h and the gauge thickness h of the warp 4. Thus, the length L can be calculated by the equation L = ((H−h) ² + P ² ) ^1/2 .

For example, the warp crimp rate C calculated by the following formula (1) using the formula for calculating the length L can be used as an index indicating the degree of bending of the woven structure of the warp 4.
C = (((H−h) ² + P ² ) ^1/2 / P−1) × 100 (%) (1)

  The warp ease of the canvas layers 3a to 3d, that is, the buckling resistance of the conveyor belt 1, can be evaluated by the warp crimp ratio C. The larger the warp crimp ratio C is, the more the canvas is subjected to repeated compressive stress. The warps 4 of the layers 3a to 3d are less likely to buckle. In the conveyor belt 1 used in the shot blasting device 6 having a small pulley diameter 7a to 7e and a large number of laminated canvas layers 3a to 3h, the warp crimp ratio C is 3.6 in order to have sufficient buckling resistance. % Or more is preferable. If the warp crimp ratio C is less than 3.6%, the woven structure of the warp 4 becomes small and linear, and it becomes easy to buckle, so that sufficient buckling resistance cannot be obtained.

In addition to actual measurement, the warp gauge thickness h is calculated by, for example, the formula h = (total warp fineness a1 (dtex) ÷ 10000 ÷ warp specific gravity b1 (g / cm ³ ) ÷ π) ^1/2 × 2 × α be able to. Here, the α value is a flatness coefficient of the warp yarn 4 and is about 0.74 as an empirical value. In addition to the actual measurement, the arrangement pitch P of the wefts 5 can be calculated by, for example, the equation P = 50 ÷ weft density (lines / 50 mm).

  Various materials such as polyester, aramid, vinylon and nylon can be used for the warp yarns 4 and the weft yarns 5 of the canvas layers 3a to 3h. The shot blasting device 6 is a pulley for attaching and detaching the conveyor belt 1 for compactness. Since the movement amount of 7a is set to be extremely small, it is necessary to keep the elongation of the conveyor belt 1 in the longitudinal direction small. For this reason, it is particularly preferable to use a material having a low elongation and high rigidity, such as polyester, for the warp yarns 4 of all the canvas layers 3a to 3h, but at least the canvas layer laminated on the innermost peripheral side of the conveyor belt 1 The material of the warps 4 of 3a and 3h may be polyester. When the warp yarn 4 is made of polyester or the like, buckling is likely to occur. Therefore, a significant improvement in buckling resistance can be expected by setting the warp crimp ratio C to 3.6% or more.

  In the manufacture of the conveyor belt 1, there is a step of applying an RFL adhesive to the canvas layers 3a to 3h, and drying and heat-stretching the RFL adhesive. At that time, the width of the canvas layers 3a to 3h slightly shrinks. This shrinkage rate is greatly affected by the degree of clogging of the warp yarns 4 and the weft yarns 5 of the canvas layers 3a to 3h, and causes a change in the curvature of the warp yarns 4. Therefore, in the present invention, an appropriate range is also defined for the total value K of the cover factors of the warp yarn 4 and the weft yarn 5 indicating the degree of clogging of the eyes.

The cover factors K1 and K2 of the warp 4 and the weft 5 are calculated by the following equations (2) and (3).
K1 = d1 × (A1 / b1) ^1/2 (2)
K2 = d2 × (A2 / b2) ^1/2 (3)

Here, d1 and d2 are the yarn density of the warp yarn 4 and the weft yarn 5 (line / 50 mm), A1 and A2 are the fineness (dtex) of the warp yarn 4 and the weft yarn 5, respectively, and b1 and b2 are the yarns of the warp yarn 4 and the weft yarn 5, respectively. Specific gravity (g / cm ³ ).

  The total value K (K1 + K2) of the cover factor is preferably 4300 or more and 5500 or less. When the total value K is less than 4300, the weft 5 contraction increases due to heating in the manufacturing process of the conveyor belt 1, and due to this, the warp 4 is less bent and sufficient to prevent buckling. It becomes difficult to ensure the degree of bending. On the other hand, when the total value K of the cover factor is more than 5500, the flexibility of the canvas layers 3a to 3h is lowered and the manufacture becomes difficult.

  In the embodiment, all the canvas layers 3a to 3h have the same specification, but only the canvas layers 3a to 3d in which compressive stress is generated by bending due to the operation of the conveyor belt 1 or the canvas layers stacked on the innermost peripheral side. Only for 3a, the warp crimp ratio C described above may be set to 3.6% or more, and the total value K of the cover factors of the warp 4 and the weft 5 may be set to 4300 or more and 5500 or less.

  As illustrated in FIG. 2, a canvas layer of the same specification having a plain weave structure in which a rubber having a predetermined thickness is coated between an upper rubber layer 6.5 mm and a lower rubber layer 3.0 (the longitudinal breaking strength of each canvas layer is A test sample of a predetermined length of about 17.5 mm in thickness with a core layer of 8 layers of about 1200 N / cm is inserted, and the warp yarn of the canvas layer is made of polyester and the material of the weft yarn is nylon. Thus, five types of test samples (Examples 1 and 2 and Comparative Examples 1 to 3) in which only the warp crimp ratio C calculated by the above equation (1) and the total value K of the cover factors of the warp and weft are changed. Was used to evaluate the buckling resistance.

  The buckling resistance was evaluated by confirming the state of the canvas layer laminated on the innermost side when each test sample was wound 180 ° around a pulley having a diameter of 200 mm, and the results are shown in Table 1. In Table 1, the case where the innermost canvas layer follows along the peripheral surface of the pulley is ○, the case where the warp does not follow and the warp yarn is easily buckled is indicated by ×, and the buckling resistance is shown. Show.

  From the results of Table 1, the use of a canvas layer satisfying the range of the warp crimp ratio C (3.6% or more) and the range of the cover factor total value K (4300 or more and 5500 or less) as an index in the present invention is the most. It was confirmed that even in the canvas layer laminated on the inner peripheral side, it is possible to prevent buckling of a high-strength polyester warp without undulation.

It is sectional drawing which illustrates a shot blasting apparatus. It is sectional drawing which illustrates the internal structure of the conveyor belt for shot blasting apparatuses of this invention. It is explanatory drawing which shows the bending state of the conveyor belt for shot blasting apparatuses of FIG. It is an expanded sectional view of the canvas layer laminated | stacked on the innermost peripheral side of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 (For shot blasting apparatus) Conveyor belt 2 Rubber layer 3 Core material 3a-3h Canvas layer 4 Warp thread 5 Weft thread 6 Shot blasting apparatus 7a-7h Pulley 8 Rotating plate 9 Projection material projection apparatus 10 Projection material 11 Storage part 12 Workpiece

Claims (4)

The core material embedded between the upper and lower rubber layers is formed by laminating a plurality of plain weave canvas layers, and a rotating plate facing the belt width direction is provided on the conveying surface. A conveyor belt for a shot blasting apparatus that rotates and agitates a workpiece in a housing portion that is surrounded by a conveying surface that is bent along the outer periphery of the rotating plate , and at least the conveyor belt of the plurality of canvas layers For the canvas layer laminated on the innermost peripheral side, the gauge thickness H of the canvas layer after molding and vulcanization, the gauge thickness h of the warp, and the arrangement pitch P of the weft are expressed by the following formula (1) A conveyor belt for a shot blasting apparatus in which the warp crimp ratio C calculated by the above is 3.6% or more and the total value K of the warp and weft cover factors K of the canvas layer is 4300 or more and 5500 or less.
C = (((H−h) ² + P ² ) ^1/2 / P−1) × 100 (%) (1)   The conveyor belt for a shot blasting apparatus according to claim 1, wherein among the plurality of canvas layers, a material for warp yarns of the canvas layer laminated at least on the innermost peripheral side of the conveyor belt is polyester.   3. The shot blasting device according to claim 1, wherein among the plurality of canvas layers, at least a canvas layer laminated on the innermost peripheral side of the conveyor belt has a longitudinal breaking strength of 1000 N / cm or more and 1500 N / cm or less. Conveyor belt.   The conveyor belt for a shot blasting apparatus according to any one of claims 1 to 3, wherein the number of canvas layers to be laminated is 6 or more and 10 or less.

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