Toothed belt

Abstract

To provide a toothed belt capable of being manufactured easily and suppressing exposure of a member buried in the toothed belt such as a core cord.SOLUTION: A toothed belt of the present invention comprises a belt body, a plurality of teeth arranged at equal intervals in a length direction on one surface of the belt body, a plurality of core cords embedded in the belt body along the length direction at intervals in a width direction of the belt body, and a canvas embedded on one side of the belt body relative to the plurality of core cords so as not to be exposed. The main component of the belt body is a thermoplastic elastomer. The canvas and the core cords are separated from each other. The canvas is in a flat form.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothed belt and a method for manufacturing the toothed belt.

Background Art

[0002] Toothed belts are used for lifting and transporting objects in factories, warehouses, and the like. This toothed belt includes a belt body, tooth portions arranged at equal intervals in the length direction on one surface of the belt body, and a plurality of core cords arranged at equal intervals in the width direction of the belt and embedded in the belt body along the length direction.

[0003] Such a toothed belt is manufactured by the following method (see Japanese Patent Application Laid-Open No. 2019-35089). First, as an inner mold, an outer peripheral surface having grooves extending in the axial direction, the grooves being provided at a predetermined pitch in the circumferential direction, and having ridges for supporting a plurality of core cords at the tip portions of the protrusions between the grooves, and the ridges extending in the axial direction is prepared. A plurality of core cords are wound around this inner diameter at equal intervals. Next, the inner mold around which the core cords are wound is set inside a cylindrical outer mold having an inner diameter larger than the outer diameter of the inner mold by the thickness of the belt body. Then, a composition (for example, a urethane composition) for forming the belt body and the tooth portions is prepared, poured between the inner mold and the outer mold, and molded. If necessary, it can be cut to a desired width to obtain a toothed belt.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional toothed belt described above, multiple core cords are embedded in the belt at equal intervals in the width direction, and are manufactured by supporting multiple core cords with protrusions. As a result, in the manufactured toothed belt, the composition is not poured into the parts where the protrusions contact the core cords, and recesses are formed on the tooth roots between the teeth, reaching down to the core cords. In other words, the multiple core cords are slightly exposed in these recesses.

[0006] The exposure of the core cord can lead to dust generation if the core cord is made of fiber, and sparks due to current flow if the core cord is made of steel. For this reason, toothed belts are required, for example, in food processing and cleanroom applications, that do not expose components embedded in the toothed belt, such as the core cord.

[0007] This invention has been made in view of these inconveniences, and aims to provide a toothed belt and a method for manufacturing a toothed belt that is easy to manufacture and can prevent the exposure of components embedded in the toothed belt, such as core cords. [Means for solving the problem]

[0008] A toothed belt according to one embodiment of the present invention comprises a belt body, a plurality of teeth arranged at equal intervals in the longitudinal direction on one surface of the belt body, a plurality of core cords spaced apart in the width direction of the belt body and embedded in the belt body along the longitudinal direction, and a canvas embedded on the side of the belt body from the plurality of core cords, wherein the main component of the belt body is a thermoplastic elastomer.

[0009] A method for manufacturing a toothed belt according to another embodiment of the present invention comprises the steps of: unwinding a strip of canvas while placing a plurality of core cords on its upper surface at intervals in the width direction; and covering the canvas on which the plurality of core cords are placed by extrusion molding with a composition mainly composed of molten thermoplastic elastomer from above and below, wherein the canvas is mesh-like. [Effects of the Invention]

[0010] The toothed belt of the present invention is easy to manufacture and can prevent the exposure of components embedded in the toothed belt, such as core cords. Furthermore, by using the manufacturing method of the toothed belt of the present invention, a toothed belt in which the exposure of components embedded in the toothed belt, such as core cords, is prevented can be easily manufactured. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic perspective view showing a toothed belt according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic oblique cross-sectional view showing the longitudinal structure of the toothed belt shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view of the toothed belt shown in Figure 1 along line AA. [Figure 4] Figure 4 is a schematic cross-sectional view of the toothed belt in Figure 1 along line BB. [Figure 5] Figure 5 is a flowchart showing a method for manufacturing a toothed belt according to another embodiment of the present invention. [Modes for carrying out the invention]

[0012] [Description of Embodiments of the Invention] First, embodiments of the present invention will be listed and described.

[0013] A toothed belt according to one embodiment of the present invention comprises a belt body, a plurality of teeth arranged at equal intervals in the longitudinal direction on one surface of the belt body, a plurality of core cords spaced apart in the width direction of the belt body and embedded in the belt body along the longitudinal direction, and a canvas embedded on the side of the belt body from the plurality of core cords, wherein the main component of the belt body is a thermoplastic elastomer.

[0014] Since the toothed belt has the canvas positioned between the plurality of core cords and one surface of the belt body, the exposure of the plurality of core cords can be suppressed. Also, since the canvas itself is embedded in the belt body, its exposure can be suppressed. Further, since the main component of the belt body is a thermoplastic elastomer, it is difficult to generate dust from the core cords and the canvas, and the toothed belt can be easily manufactured by extrusion molding.

[0015] The belt body may be composed of a single layer. By configuring the belt body as a single layer in this way, the toothed belt can be manufactured more easily.

[0016] The canvas and the plurality of core cords may be separated. By separating the canvas and the plurality of core cords in this way, wear due to contact between the canvas and the core cords can be suppressed, so the life of the toothed belt can be extended.

[0017] The canvas may be in a mesh shape. By making the canvas in a mesh shape in this way, the exposure of the canvas itself can be more reliably suppressed.

[0018] As the porosity of the mesh of the canvas, it is preferably 35% or more and 95% or less. By setting the porosity of the mesh of the canvas within the above range, while suppressing the exposure of the canvas itself, it is possible to easily control the embedding positions of the plurality of core cords.

[0019] The fibers of the canvas may include at least one of polyamide fibers and polyester fibers. By including at least one of polyamide fibers and polyester fibers in the fibers of the canvas in this way, the rigidity of the tooth portion increases and the skip torque can be increased. Also, the occurrence of tooth chipping can be suppressed.

[0020] The above thermoplastic elastomer may contain at least one of thermoplastic polyurethane, thermoplastic polyester, and thermoplastic polyamide. By including at least one of thermoplastic polyurethane, thermoplastic polyester, and thermoplastic polyamide in the above thermoplastic elastomer, the toothed belt can be manufactured more easily.

[0021] The above belt body preferably has no recess on the bottom surface of the teeth between the teeth. When there is a recess on the bottom surface of the teeth between the teeth, the belt body is likely to bend starting from the recess. Therefore, when wound around a pulley, it bends into a polygonal shape and the flexural fatigue resistance decreases. On the other hand, by making the above belt body have no recess on the bottom surface of the teeth between the teeth, it is possible to prevent bending into a polygonal shape and improve the flexural fatigue resistance.

[0022] A method for manufacturing a toothed belt according to another embodiment of the present invention includes a step of feeding out a strip-shaped canvas while placing a plurality of core cords thereon at intervals in the width direction on its upper surface, and a step of coating from above and below the canvas on which the plurality of core cords are placed by extrusion molding with a composition mainly composed of a molten thermoplastic elastomer, wherein the canvas is in a mesh shape.

[0023] In the method for manufacturing the toothed belt, the positions of the plurality of core cords in the thickness direction of the belt body can be adjusted by supporting the plurality of core cords with the canvas. Further, in the method for manufacturing the toothed belt, since the canvas is in a mesh shape, when extrusion molding is performed, the composition mainly composed of the molten thermoplastic elastomer passes through the mesh of the canvas, so it is possible to prevent the canvas itself from being extruded and exposed from the belt body. Therefore, by using the method for manufacturing the toothed belt, it is possible to easily manufacture a toothed belt in which the exposure of the core cords and the canvas is suppressed by extrusion molding.

[0024] Here, the "main component" is the component with the highest content, for example, a component contained at 50% by mass or more. [[ID=第十八条]]

[0025] [Details of Embodiments of the Present Invention] Hereinafter, a toothed belt and a method for manufacturing a toothed belt according to one embodiment of the present invention will be described with reference to the drawings as appropriate.

[0026] [Toothed belt] The toothed belt 1 shown in Figures 1 to 4 comprises a belt body 10, a plurality of teeth 20 arranged at equal intervals along the length on one side of the belt body 10, a plurality of core cords 30 spaced apart in the width direction of the belt body 10 and embedded in the belt body 10 along the length, and a canvas 40 embedded on the side of the belt body 10 that is further away from the plurality of core cords 30.

[0027] <Belt body> The main component of the belt body 10 is a thermoplastic elastomer. The thermoplastic elastomer may contain at least one of thermoplastic polyurethane, thermoplastic polyester, and thermoplastic polyamide. By including at least one of thermoplastic polyurethane, thermoplastic polyester, and thermoplastic polyamide in the thermoplastic elastomer in this way, the toothed belt 1 can be manufactured more easily.

[0028] The belt body 10 is preferably made of a single layer. In other words, the belt body 10 does not have a layered structure and is formed as a single unit. By making the belt body 10 a single layer in this way, the toothed belt 1 can be manufactured more easily.

[0029] Furthermore, the belt body 10 does not have recesses on the tooth roots between the teeth 20. In other words, the belt body 10 is configured to have a uniform thickness. If there are recesses on the tooth roots between the teeth 20, the belt body 10 will be more prone to bending starting from those recesses. As a result, when wrapped around a pulley, it will bend into a polygonal shape, reducing bending fatigue resistance. In contrast, by making the belt body 10 not have recesses on the tooth roots between the teeth 20, it is possible to suppress bending into a polygonal shape and improve bending fatigue resistance.

[0030] The average thickness of the belt body 10 is determined appropriately based on the required strength of the toothed belt 1, but can be, for example, 1 mm or more and 15 mm or less. Throughout this specification, "average" refers to the average value of measurements taken at any 10 points.

[0031] The length of the belt body 10 is determined appropriately according to the application of the toothed belt 1. The toothed belt 1 can be used as a closed belt that circulates between a pair of pulleys, or as an open belt with ends.

[0032] The belt body 10 may contain various additives. Examples of such additives include antioxidants, heat stabilizers, light stabilizers, anti-fogging agents, flame retardants, surface modifiers, pigments, fillers, waxes, and the like.

[0033] <Dental Department> The teeth 20 have a cross-section that is a convex shape such as a trapezoid, triangle, semicircle, mountain shape, wave shape, or normal distribution curve. Furthermore, the teeth 20 are arranged so that their edges (axial direction) coincide with the width direction of the belt body 10. The cross-sectional shape of the teeth 20 may be specified in accordance with standards such as JIS, ISO, and DIN.

[0034] The average height of the teeth 20 and the pitch between the teeth 20 are determined appropriately according to the application of the toothed belt 1. The average height of the teeth 20 can be, for example, 1.0 mm or more and 10 mm or less. The pitch between the teeth 20 can be, for example, 2 mm or more and 25 mm or less.

[0035] The main components of the teeth 20 can be the same as those of the belt body 10. Furthermore, the teeth 20 may contain the same additives as those in the belt body 10.

[0036] <Core cord> The multiple core cords 30 are linear bodies having a circular cross-section.

[0037] The multiple core cords 30 are embedded in the belt body 10 as described above. In other words, the multiple core cords 30 are not exposed. These multiple core cords 30 are arranged parallel to the length of the belt body 10 and at a constant distance from the other surface of the belt body 10 (the surface on which the teeth 20 are not arranged). In other words, the multiple core cords 30 are arranged in a planar shape, and the plane formed by these multiple core cords 30 is parallel to the other surface of the belt body 10. Furthermore, the multiple core cords 30 are arranged at equal intervals. These multiple core cords 30 can improve the strength, durability, and driving accuracy of the toothed belt 1.

[0038] Each core cord 30 may consist of a single core wire, or it may consist of multiple core wires twisted together. The core wires constituting the core cord 30 may include at least one of aramid core wires, steel core wires, carbon core wires, and polyester core wires. In other words, a core cord 30 composed of multiple core wires may consist of one type of core wire, or it may consist of two or more types of core wires. Multiple core cords 30 may consist of different core wires or combinations of different core wires, but it is preferable to have the same core wire configuration in order to ensure uniformity in the width direction of the belt body 10.

[0039] The cross-sectional diameter of each core cord 30 is not particularly limited, but is generally between 0.2 mm and 2.5 mm.

[0040] The lower limit of the average spacing between multiple core cords 30 (the average distance between the central axes of the core cords 30) is preferably 0.3 mm, and more preferably 0.5 mm. On the other hand, the upper limit of the above average spacing is preferably 4 mm, and more preferably 3 mm. If the above average spacing is less than the above lower limit, the flexibility of the toothed belt 1 may be insufficient. Conversely, if the above average spacing exceeds the above upper limit, the improvement in the strength, durability, and driving accuracy of the belt by the multiple core cords 30 may be insufficient.

[0041] Furthermore, the lower limit of the average distance between the central axis of the outermost core cord 30 and the adjacent side surface of the belt body 10 is preferably 0.3 mm, and more preferably 0.5 mm. On the other hand, the upper limit of the average distance is preferably 2 mm, and more preferably 1.6 mm. If the average distance is less than the lower limit, the outermost core cord 30 may be exposed from the side surface of the belt body 10 during the manufacturing of the toothed belt 1. Conversely, if the average distance exceeds the upper limit, the side edges of the belt body 10 may flap more easily during operation, and the effect of improving the accuracy of operation by multiple core cords 30 may be insufficient. Note that there are two outermost core cords 30, one on each side of the belt body 10.

[0042] The number of core cords 30 is determined by the average width of the belt body 10, the average spacing between multiple core cords 30, and the average distance between the core cords 30 and the side of the belt body 10, but the number of core cords 30 is usually between 10 and 100.

[0043] <Canvas> As shown in Figure 2, the canvas 40 is mesh-like. By making the canvas 40 mesh-like in this way, exposure of the canvas 40 itself can be more reliably suppressed.

[0044] In Figure 2, the canvas 40 is woven from multiple weft threads 41 arranged in the width direction of the belt body 10 and multiple warp threads 42 arranged in the conveying direction (longitudinal direction of the belt body 10), and has a rectangular void 43 surrounded by two adjacent weft threads 41 and two adjacent warp threads 42. Note that the mesh structure of the canvas 40 is not limited to the rectangular shape shown in Figure 2; for example, the void 43 may be hexagonal.

[0045] The fibers of the canvas 40 (the weft 41 and warp 42 fibers in Figure 2) may contain at least one of polyamide fibers and polyester fibers. By including at least one of polyamide fibers and polyester fibers in the fibers of the canvas 40 in this way, the rigidity of the teeth 20 is increased, and the skip torque can be enhanced. In addition, the occurrence of tooth chipping can be suppressed.

[0046] The lower limit of the average fiber thickness of the canvas 40 is preferably 5 decitex, and more preferably 6 decitex. On the other hand, the upper limit of the average fiber thickness is preferably 200 decitex, and more preferably 150 decitex. If the average fiber thickness is below the lower limit, the strength of the canvas 40 may be insufficient. Conversely, if the average fiber thickness exceeds the upper limit, the flexibility of the belt body 10 in the conveying direction may be insufficient, making it difficult to use in belt conveyors, especially those with small pulley diameters.

[0047] The lower limit of the void ratio of the mesh of the canvas 40 is preferably 35%, and more preferably 40%. On the other hand, the upper limit of the void ratio is preferably 95%, and more preferably 90%. If the void ratio is less than the lower limit, when the toothed belt 1 is manufactured by extrusion molding, when the composition mainly composed of thermoplastic elastomer that constitutes the belt body 10 is injected, the pressure may cause the canvas 40 to move easily, and the canvas 40 itself may be easily exposed on the surface of the belt body 10. In contrast, by setting the void ratio to or above the lower limit, when the composition is injected, the composition can pass through the voids 43 of the mesh of the canvas 40, so that the pressure can prevent the canvas 40 from moving. Therefore, exposure of the canvas 40 itself can be prevented. Conversely, if the void ratio exceeds the upper limit, the strength of the canvas 40 may be insufficient, and it may not be able to adequately support the multiple core cords 30 that are placed on the canvas 40 and unwound when the toothed belt 1 is manufactured by extrusion molding. As a result, it may become difficult to control the embedded positions of the multiple core cords 30. Note that the "void ratio of the mesh" is a value calculated by dividing the total area of ​​geometric gaps (parts not occupied by threads in a plan view) observed from the surface of the canvas by the total area of ​​the observed field of view.

[0048] The canvas 40 and the multiple core cords 30 should be spaced apart, as shown in Figure 4. By spacing the canvas 40 and the multiple core cords 30 in this way, wear caused by contact between the canvas 40 and the core cords 30 can be suppressed, thereby extending the life of the toothed belt 1.

[0049] The canvas 40 is not exposed. Therefore, the width of the canvas 40 is narrower than the width of the belt body 10. On the other hand, since the canvas 40 also supports the multiple core cords 30 that are placed on and unwound when the toothed belt 1 is manufactured by extrusion molding, the width of the canvas 40 is wider than the width of the plane formed by the multiple core cords 30. In addition, both ends of the canvas 40 in the width direction are located outside the ends of the plane formed by the multiple core cords 30.

[0050] <Advantages> In the toothed belt 1, the canvas 40 is positioned between the multiple core cords 30 and one side of the belt body 10, thus preventing the exposure of the multiple core cords 30. Furthermore, in the toothed belt 1, the canvas 40 itself is embedded in the belt body 10, thus preventing its exposure. Moreover, since the main component of the belt body 10 of the toothed belt 1 is a thermoplastic elastomer, dust generation from the core cords and canvas is minimal, and the toothed belt 1 can be easily manufactured by extrusion molding.

[0051] [Method for manufacturing toothed belts] A method for manufacturing a toothed belt according to another embodiment of the present invention, as shown in Figure 5, comprises an extrusion step S1, a coating step S2, and a tooth formation step S3. The toothed belt 1 shown in Figures 1 to 4 can be manufactured by this method.

[0052] <Manipulation process> In the unwinding process S1, a strip of canvas 40 is unwound while multiple core cords 30 are placed on its upper surface at intervals in the width direction. The canvas 40 is mesh-like.

[0053] Specifically, while the canvas 40 is dispensed from a pre-prepared roll of canvas 40, multiple core cords 30 are inserted into a crosshead attached to the tip of the extruder's cylinder and placed on the dispensed canvas 40. As a result, the multiple core cords 30 are arranged at equal intervals in a planar manner.

[0054] <Coating process> In coating step S2, the canvas 40 on which the multiple core cords 30 are placed is coated from above and below by extrusion molding with a composition mainly composed of molten thermoplastic elastomer. In coating step S2, the canvas 40 on which the multiple core cords 30 are placed is arranged so that the canvas 40 is on the bottom and the multiple core cords 30 are on the top. Since this method of manufacturing a toothed belt uses extrusion molding with a composition mainly composed of thermoplastic elastomer, the toothed belt can be easily made longer.

[0055] This covering process S2 yields an extruded molded body in which multiple core cords 30 and canvas 40 are embedded. This extruded molded body, either itself or a part thereof, constitutes the belt body 10.

[0056] Since the canvas 40 is mesh-like, the above composition passes through the voids 43 in the mesh of the canvas 40 even when pressure is applied by extrusion molding, preventing the canvas 40 from moving in the vertical direction. Therefore, it is possible to prevent the canvas 40 from being exposed on the surface of the belt body 10.

[0057] Furthermore, the pressure from the downward extrusion molding causes the composition to pass through the mesh gaps 43 of the canvas 40 from below, pushing up the multiple core cords 30. This upward pressure lifts the multiple core cords 30, separating them from the canvas 40. Also, when lifting the multiple core cords 30, the upward pressure and the weight of the core cords 30 are balanced, so that the multiple core cords 30 are arranged in a planar shape, and the plane formed by these multiple core cords 30 can be positioned parallel to the other surface of the belt body 10. In other words, by using a toothed belt manufacturing method, the multiple core cords 30 can be embedded in a suitable position in the belt body 10.

[0058] The lower limit of the melting temperature of the above composition is preferably 170°C, and more preferably 180°C. On the other hand, the upper limit of the melting temperature of the above composition is preferably 210°C, and more preferably 200°C. If the melting temperature of the above composition is below the lower limit, the viscosity of the molten composition will be high, which may make it difficult to embed the core cord 30 in a suitable position in the belt body 10. Conversely, if the melting temperature of the above composition exceeds the upper limit, the viscosity of the molten composition will be low, which may make extrusion molding difficult.

[0059] <Tooth formation process> In the tooth formation step S3, teeth 20 are formed on the extruded body after the coating step S2. This allows the toothed belt 1 to be obtained.

[0060] Specifically, for example, a cylindrical mold roll having recesses corresponding to the teeth 20 on its outer surface can be prepared, and the teeth 20 can be formed by heating one side of the extruded body and wrapping it around the mold roll.

[0061] Alternatively, the teeth 20 may be formed by melt-bonding them to the extruded body.

[0062] <Advantages> In this toothed belt manufacturing method, the positions of the multiple core cords 30 in the thickness direction of the belt body 10 can be adjusted by supporting the multiple core cords 30 with the canvas 40. Furthermore, in this toothed belt manufacturing method, since the canvas 40 is mesh-like, when extruded, the composition mainly composed of molten thermoplastic elastomer passes through the mesh of the canvas 40, thus preventing the canvas 40 itself from being pushed out from the belt body 10 and exposed. Therefore, by using this toothed belt manufacturing method, a toothed belt in which the exposure of the core cords 30 and canvas 40 is suppressed by extrusion molding can be easily manufactured.

[0063] [Other embodiments] The present invention is not limited to the embodiments described above, and can be implemented in various modified and improved forms in addition to those described above.

[0064] In the above embodiment, a configuration was described in which the belt body does not have recesses on the tooth roots between the teeth. However, depending on the meshing with the pulley, the belt body can also be configured to have recesses on the tooth roots between the teeth. In this case, the recesses are provided so that the canvas and multiple core cords are not exposed.

[0065] In the above embodiment, the case where the canvas is mesh-like was described, but it is also possible to use a canvas that is not mesh-like, that is, one that is tightly woven and has no gaps.

[0066] In the above embodiment, a method for manufacturing the toothed belt of the present invention by extrusion molding was described, but the toothed belt can also be manufactured by other methods. The toothed belt can also be manufactured by the following manufacturing method, for example: Prepare an inner mold having recesses corresponding to the teeth, and an outer mold positioned outside the inner mold and spaced apart by the thickness of the belt body from the outer diameter of the inner mold. A canvas 40 on which a plurality of core cords 30 are placed is sandwiched between the inner mold and the outer mold so that the canvas 40 faces the inner mold, and a composition mainly composed of molten thermoplastic elastomer is poured between the inner mold and the outer mold and pressurized to obtain the toothed belt. [Examples]

[0067] The present invention will be described in more detail below with reference to examples and comparative examples, but the invention is not limited to the following examples.

[0068] [Example 1] Using a steel cord as the core cord, a mesh-like canvas with a void ratio of 80%, and a composition mainly composed of a thermoplastic elastomer, a toothed belt of Example 1 was manufactured by extrusion molding according to the toothed belt manufacturing method of the present invention described above. In the manufacturing method of the toothed belt of Example 1, no protrusions (hereinafter also simply referred to as "projection supports") supporting the core cord were used.

[0069] [Example 2] A toothed belt of Example 2 was manufactured in the same manner as in Example 1, except that an aramid cord was used as the core cord.

[0070] [Comparative Example 1, Comparative Example 2] The toothed belts of Comparative Examples 1 and 2 were manufactured in the same manner as in Examples 1 and 2, except that canvas was not used and the core cord was supported by protruding supports. In the toothed belts of Comparative Examples 1 and 2, because protruding supports were used, the core cord was exposed in the recesses of the belt body formed by these protruding supports. In other words, in these toothed belts, the core cord is not embedded in the belt body.

[0071] [Comparative Example 3] A toothed belt of Comparative Example 3 was manufactured in the same manner as in Example 1, except that a non-mesh (0% void ratio) canvas was used and the canvas was supported by protruding supports to manufacture the toothed belt. In the toothed belt of Comparative Example 3, because protruding supports were used, the canvas was exposed in the recesses of the belt body formed by these protruding supports. In other words, in this toothed belt, the canvas is not embedded in the belt body.

[0072] [Comparative Example 4] A toothed belt of Comparative Example 4 was manufactured by seamless molding using a composition mainly composed of steel cord and thermosetting elastomer as the core cord. Note that canvas was not used in the toothed belt of Comparative Example 4. Furthermore, because a projection support was used, the core cord was exposed in the recess of the belt body formed by this projection support. In other words, in this toothed belt, the core cord was not embedded in the belt body.

[0073] [evaluation] The toothed belts of Example 1, Example 2, and Comparative Examples 1 to 4 were evaluated as follows. The results are shown in Table 1.

[0074] (Dust generation) For all toothed belts, we conducted actual use tests to determine whether or not dust was generated from the core cord and canvas, which are particularly important to suppress in food-related applications. The determination was made by visual inspection.

[0075] (spark) For Example 1, Comparative Example 1, Comparative Example 3, and Comparative Example 4, which use steel cords, the presence or absence of sparks was determined. Specifically, a current of 0.2A to 0.3A was passed through the steel cord, and the presence or absence of sparks was visually confirmed.

[0076] (Flexion fatigue) The flexural fatigue resistance was assessed for all toothed belts. Specifically, based on how the toothed belt was wrapped around the pulley in use, if the core wire constituting the core cord was arc-shaped (no bending), it was determined to have high flexural fatigue resistance (high in Table 1), and if it was polygonal (with bending), it was determined to have low flexural fatigue resistance (low in Table 1). The assessment was performed by visually observing the shape of the core cord of the toothed belt from the outside using a microscope.

[0077] [Table 1]

[0078] In Table 1, a "-" in the columns for void ratio and canvas exposure means that there is no canvas. A "-" in the column for sparks means that it is not subject to evaluation. In addition, the "Long-length specification" column in Table 1 indicates whether or not it is possible to manufacture long-length belts for each example and comparative example's belt specifications and manufacturing method. "Yes" means that it is possible to manufacture long-length belts, and "No" means that it is not possible to manufacture long-length belts.

[0079] The results in Table 1 show that in the toothed belts of Examples 1 and 2, where the main component of the belt body is a thermoplastic elastomer and the core cord and canvas are embedded in the belt body, the exposure of the embedded components is suppressed, and the generation of dust and sparks in the conductive cord can be reduced.

[0080] On the other hand, in the toothed belts of Comparative Examples 1 to 4, because protruding supports are used, exposure to the core cord or canvas is observed, and dust generation is observed in these toothed belts. Furthermore, in Comparative Examples 1, 2, and 4, which use conductive steel cord, spark generation is observed. In addition, in the toothed belt of Comparative Example 4, the main component of the belt body is thermosetting and it is manufactured by seamless molding, so it is not possible to manufacture long toothed belts. [Industrial applicability]

[0081] The toothed belt of the present invention is easy to manufacture and can prevent the exposure of components embedded in the toothed belt, such as core cords. Furthermore, by using the manufacturing method of the toothed belt of the present invention, a toothed belt in which the exposure of components embedded in the toothed belt, such as core cords, is prevented can be easily manufactured. [Explanation of Symbols]

[0082] 1. Toothed belt 10 Belt body 20 Teeth 30 core cord 40 Canvas 41 Weft 42 warp threads 43 gaps

Claims

1. The belt itself, Multiple teeth are arranged at equal intervals along the length of one side of the belt body, Multiple core cords are embedded in the belt body at intervals in the width direction and along the length direction, On one side of the belt body, from the multiple core cords, a canvas is embedded so as not to be exposed. Equipped with, The main component of the belt body is a thermoplastic elastomer. The canvas and the multiple core cords mentioned above are separated, The above canvas is a flat, toothed belt.

2. The toothed belt according to claim 1, wherein the belt body is composed of a single layer.

3. The toothed belt according to claim 1 or claim 2, wherein the canvas is mesh-like.

4. The toothed belt according to claim 3, wherein the void ratio of the mesh of the canvas described above is 35% or more and 95% or less.

5. The toothed belt according to any one of claims 1 to 4, wherein the fibers of the canvas described above include at least one of polyamide fibers and polyester fibers.

6. The toothed belt according to any one of claims 1 to 5, wherein the thermoplastic elastomer comprises at least one of thermoplastic polyurethane, thermoplastic polyester, and thermoplastic polyamide.

7. The toothed belt according to any one of claims 1 to 6, wherein the belt body has no recesses on the tooth root surfaces between the teeth.

Images