Toothed belt

Abstract

To provide a toothed belt capable of suppressing increase of a width while securing the number of core body cords required for wiring of electrical signals or a power supply.SOLUTION: A toothed belt comprises: a belt body; a plurality of tooth parts disposed at an equal interval in a length direction on one surface of the belt body; and a plurality of core body cords embedded in the belt body along the length direction at intervals in a width direction of the belt body. The plurality of core body cords has a conductive core body cord for energization, and a reinforcing core body cord that has a higher electrical resistance per unit length than the core body cord for energization.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a toothed belt. [Background technology]

[0002] Toothed belts are used for lifting and transporting objects in factories, warehouses, etc. This toothed belt includes a belt body, teeth 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] The toothed belt can be configured as an endless belt with no end and an open belt with both ends. Of these, the toothed belt with the open belt configuration is fixed to a cart so that its teeth can be fitted into a toothed pulley, and is used to move the cart up and down or left and right by rotating the toothed pulley.

[0004] Some of the above-mentioned carts are equipped with stoppers to prevent the loaded cargo from slipping off the cart. These stoppers may be electrically controlled so that they can be stored so as not to be an obstacle when loading or unloading cargo onto or from the cart. In this way, carts are often equipped with additional functions that are electrically controlled.

[0005] A toothed belt has been proposed in which the wiring for electrical signals and power sources (hereinafter simply referred to as "wiring") that control such additional functions is also used as a core cord (see JP 2019-60403 A). In this toothed belt, the core cord is made of a material that can pass electricity, so that it also serves as a power supply cable, and therefore the wiring can be embedded within the toothed belt while preventing an increase in the thickness of the toothed belt. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-60403 A Summary of the Invention [Problem to be solved by the invention]

[0007] When the core cord of the toothed belt is also used as wiring, the number of core cords is determined by the greater of the number determined by the strength required for the toothed belt and the number of required wirings. Therefore, if the number of wirings is large, the number of core cords is determined by the number of wirings, and the width of the toothed belt tends to become unnecessarily large. If the width of the toothed belt becomes unnecessarily large, it may be difficult to reduce the size of the device incorporating the toothed belt, such as a cart.

[0008] The present invention has been made in view of the above-mentioned inconveniences, and has an object to provide a toothed belt that can suppress an increase in width while ensuring the number of core cords required for wiring electrical signals and power sources. [Means for solving the problem]

[0009] The toothed belt of the present invention comprises a belt body, a plurality of teeth arranged at equal intervals in the longitudinal direction on one side of the belt body, and 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, the plurality of core cords having conductive current-carrying core cords and reinforcing core cords having a higher electrical resistance per unit length than the current-carrying core cords.

[0010] In this toothed belt, the electrical resistance per unit length of the current-carrying core cord is lower than that of the reinforcing core cord, so the number of parallel current-carrying core cords required to ensure the electrical resistance required for current flow can be reduced. Also, the strength of this toothed belt can be maintained mainly by the reinforcing core cord. Therefore, the number of core cords required can be reduced, so that the number of core cords required for wiring electrical signals and power sources can be ensured while preventing an increase in width.

[0011] The material of the electric core cord may be different from the material of the reinforcing core cord. By making the material of the electric core cord different from the material of the reinforcing core cord in this way, it becomes possible to use an electric core cord with a low electrical resistivity, and therefore it is easy to reduce the number of parallel electric core cords for ensuring the required electrical resistance.

[0012] The average diameter of the electric core cord may be larger than the average diameter of the reinforcing core cord. By making the average diameter of the electric core cord larger than the average diameter of the reinforcing core cord in this manner, the electrical resistance per unit length of the electric core cord can be easily reduced.

[0013] The two core cords positioned on the outermost side in the width direction may be reinforcing core cords. The electrical resistance of the two core cords positioned on the outermost side in the width direction may increase over time due to wear caused by friction from the side of the toothed belt. For this reason, the two core cords positioned on the outermost side in the width direction are reinforcing core cords, and are not used for wiring for electrical signals or power, thereby improving the reliability of the wiring.

[0014] The plurality of core cords may include a plurality of the electric core cords, and the reinforcing core cord may be disposed between adjacent electric core cords. By disposing the reinforcing core cord between adjacent electric core cords in this manner, it is possible to prevent a local decrease in strength of the toothed belt. Effect of the Invention

[0015] As described above, the toothed belt can suppress an increase in width while ensuring the number of core cords required for wiring electrical signals and power sources. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic perspective view showing a toothed belt according to an embodiment of the present invention; [Diagram 2] 2 is a schematic cross-sectional view of the toothed belt of FIG. 1 taken along line AA. [Diagram 3] FIG. 2 is a schematic cross-sectional view of the toothed belt taken along line BB in FIG. 1. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a toothed belt different from that in FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing a toothed belt different from that shown in FIGS. 3 and 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0018] The toothed belt 1 shown in Figures 1, 2 and 3 comprises a belt body 10, a plurality of teeth 20 arranged at equal intervals in the longitudinal direction on one side of the belt body 10, and nine core cords 30 embedded in the belt body 10 along the longitudinal direction.

[0019] <Belt body> The main component of the belt body 10 is rubber or resin. Examples of the rubber include ethylene-α-olefin elastomers such as ethylene-propylene rubber (EPR) and ethylene propylene diene monomer rubber (EPDM), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), and hydrogenated nitrile rubber (H-NBR). The rubber may be one of these, or may be a blend of two or more of these. Examples of the resin include thermoplastic polyester, polyamide, and polyurethane. The main component of the belt body 10 is preferably a resin from the viewpoint of low dust generation, and among them, thermoplastic urethane, which has excellent abrasion resistance, is preferable. Here, the term "main component" refers to the component with the highest content, and preferably refers to a component with a content of 50% by mass or more, and more preferably 90% by mass or more.

[0020] The average thickness of the belt body 10 is appropriately determined depending on the strength required for the toothed belt 1, and can be, for example, 1 mm or more and 10 mm or less.

[0021] The length of the belt body 10 is determined appropriately depending on the application of the toothed belt 1. The toothed belt 1 is mainly used as an open belt having both ends.

[0022] The belt body 10 may contain various additives, such as antioxidants, heat stabilizers, light stabilizers, anti-fogging agents, flame retardants, surface conditioners, pigments, fillers, waxes, and the like.

[0023] <Tooth> The tooth portion 20 is a convex portion having a cross section of a trapezoid, a triangle, a semicircle, a mountain shape, a wave shape, a normal distribution curve shape, etc. The tooth portion 20 is arranged so that its ridge line (axial direction) coincides with the width direction of the belt body 10.

[0024] The average height of the toothed portion 20 and the pitch between the toothed portions 20 are appropriately determined depending on the application of the toothed belt 1. The average height of the toothed portion 20 can be, for example, 1.0 mm or more and 10 mm or less. The pitch between the toothed portions 20 can be, for example, 2 mm or more and 25 mm or less.

[0025] The main component of the toothed portion 20 may be the same as that of the belt body 10. The toothed portion 20 may also contain the same additives as those of the belt body 10.

[0026] <Core Code> The nine core cords 30 are linear bodies having a circular cross section, and are aligned in the width direction of the belt body 10 as shown in FIG.

[0027] The nine core cords 30 include four conductive current-carrying core cords 31 and five reinforcing core cords 32 having a higher electrical resistance per unit length than the current-carrying core cords 31 .

[0028] (Material) Examples of materials for the conductive core cord 31 include steel and copper. Among them, copper, which has a low electrical resistivity, is preferable.

[0029] The current-carrying core cord 31 may also be one in which the conductor such as steel or copper is covered with an insulating layer. By covering with an insulating layer in this way, even if the current-carrying core cord 31 comes into contact with an adjacent core cord 30, the electric signal or power supply function of the current-carrying core cord 31 is unlikely to be affected. The main component of the insulating layer may be, for example, ethylene-tetrafluoroethylene copolymer (ETFE).

[0030] The reinforcing core cord 32 may be conductive as long as it has a higher electrical resistance per unit length than the electric core cord 31, but it is preferable that the reinforcing core cord 32 is insulating. By making the reinforcing core cord 32 insulating, even if it comes into contact with the electric core cord 31, it is unlikely to affect the electric signal or the function of the electric core cord 31 as a power source. Therefore, it is possible to narrow the gap between the electric core cord 31 and the reinforcing core cord 32, which makes it easy to prevent an increase in the width of the toothed belt 1.

[0031] Examples of the material for the conductive reinforcing core cord 32 include the same materials as those for the conductive core cord 31. Examples of the material for the insulating reinforcing core cord 32 include aramid, glass, polyester, etc.

[0032] The material of the current-carrying core cord 31 and the material of the reinforcing core cord 32 can be the same, but it is preferable that the material of the current-carrying core cord 31 is different from the material of the reinforcing core cord 32. By making the material of the current-carrying core cord 31 different from the material of the reinforcing core cord 32 in this way, it becomes possible to use a material with low electrical resistivity as the current-carrying core cord 31, and it is easy to reduce the number of parallel current-carrying core cords 31 to ensure the required electrical resistance. In particular, it is preferable that the material of the current-carrying core cord 31 is copper, which has low electrical resistivity, and the material of the reinforcing core cord 32 is aramid, which has insulating properties.

[0033] In addition, when both the conductive core cord 31 and the reinforcing core cord 32 are conductive, it is preferable that the conductive core cord 31 is a copper cord which is a copper wire covered with an insulating layer, and the reinforcing core cord 32 is a steel cord having a steel wire.

[0034] Copper has low electrical resistance per unit length and is suitable for electrical current applications. On the other hand, copper wire is easily bent, so by using a copper cord covered with an insulating layer, it is possible to prevent defects such as wire breakage. In addition, steel cords have high rigidity and can maintain their strength even when they have a small diameter. This steel cord can be configured without a covering layer. Since the copper cord that is the electrical current core cord 31 has an insulating layer covering its periphery, even if a steel cord without a covering layer comes into contact with the electrical current core cord 31, the electrical signal or power supply function of the electrical current core cord 31 is unlikely to be affected. In this way, the steel cord does not need to be provided with an insulating layer and can be made small in diameter, so it does not require any space in the width direction. Therefore, by using a steel cord as the reinforcing core cord 32, it is possible to maintain the strength of the toothed belt while ensuring a wide area for the electrical current core cord 31. From the above, by using a copper cord coated with an insulating layer as the conductive core cord 31 and a steel cord as the reinforcing core cord 32, it is possible to further suppress an increase in the width of the toothed bell while ensuring the number of core cords required for wiring electrical signals and power sources.

[0035] The main component of the insulating layer of the copper cord is preferably ethylene-tetrafluoroethylene copolymer (ETFE).

[0036] Either or both of the copper wires of the copper cord and the steel wires of the steel cord may be twisted wires.

[0037] (average diameter) The lower limit of the average diameter of the electric current core cord 31 is preferably 0.2 mm, more preferably 0.5 mm, and even more preferably 1 mm. On the other hand, the upper limit of the average diameter of the electric current core cord 31 is preferably 2.5 mm, and more preferably 1.5 mm. If the average diameter of the electric current core cord 31 is less than the lower limit, the electric resistance of the electric current core cord 31 may not be sufficiently reduced, and the electric current core cord 31 may not fully function as an electric signal or power source. On the other hand, if the average diameter of the electric current core cord 31 exceeds the upper limit, the width of the toothed belt 1 may become too large.

[0038] The lower limit of the average diameter of the reinforcing core cord 32 is preferably 0.1 mm, more preferably 0.2 mm, and even more preferably 0.5 mm. On the other hand, the upper limit of the average diameter of the reinforcing core cord 32 is preferably 2 mm, and more preferably 1 mm. If the average diameter of the reinforcing core cord 32 is less than the lower limit, the strength of the reinforcing core cord 32 may be insufficient. Conversely, if the average diameter of the reinforcing core cord 32 exceeds the upper limit, the width of the toothed belt 1 may become too large.

[0039] The average diameter of the electric current core cord 31 is preferably larger than the average diameter of the reinforcing core cord 32. By making the average diameter of the electric current core cord 31 larger than the average diameter of the reinforcing core cord 32 in this manner, it is possible to easily reduce the electrical resistance per unit length of the electric current core cord 31. In particular, when the material of the electric current core cord 31 and the material of the reinforcing core cord 32 are the same, by making the average diameter of the electric current core cord 31 larger than the average diameter of the reinforcing core cord 32, it is possible to reduce the electrical resistance per unit length.

[0040] (array) As shown in Fig. 3, the nine core cords 30 (four conductive core cords 31 and five reinforcing core cords 32) are arranged so that the shortest distance from one surface of the belt body 10 (the surface on which the teeth 20 are arranged) to the outer periphery of the core cords 30 is constant. By arranging them in this manner, the belt body 10 can be easily manufactured by extrusion molding while supporting the nine core cords 30 from below.

[0041] The two core cords 30 positioned at the outermost positions in the width direction of the toothed belt 1 may be reinforcing core cords 32. The electrical resistance of the two core cords 30 positioned at the outermost positions in the width direction may increase over time due to wear caused by friction from the side of the toothed belt 1. For this reason, the two core cords 30 positioned at the outermost positions in the width direction are used as reinforcing core cords 32 and are not used for wiring for electrical signals or power, thereby improving the reliability as wiring.

[0042] The lower limit of the average distance between the central axis of the reinforcing core cord 32 arranged on the outermost side and the side surface of the belt body 10 adjacent thereto (also referred to as the "average distance between the reinforcing core cord 32 and the side surface of the belt body 10") is preferably 0.3 mm, more preferably 0.5 mm. On the other hand, the upper limit of the average distance between the reinforcing core cord 32 and the side surface of the belt body 10 is preferably 1 mm, more preferably 0.7 mm. If the average distance between the reinforcing core cord 32 and the side surface of the belt body 10 is less than the lower limit, there is a risk that the reinforcing core cord 32 arranged on the outermost side will be exposed from the side surface of the belt body 10 during the manufacture of the toothed belt 1. Conversely, if the average distance between the reinforcing core cord 32 and the side surface of the belt body 10 exceeds the upper limit, the side edge of the belt body 10 will be easily fluttered during driving, and the effect of improving the driving accuracy by the core cord 30 may be insufficient.

[0043] It is also preferable that the reinforcing core cords 32 are disposed between adjacent electric current core cords 31. By disposing the reinforcing core cords 32 between adjacent electric current core cords 31 in this manner, it is possible to prevent the strength of the toothed belt 1 from being locally reduced.

[0044] 3, the four conductive core cords 31 and the five reinforcing core cords 32 are arranged alternately from the outside in the width direction in the order of the reinforcing core cords 32 and the conductive core cords 31. With such an arrangement, it becomes easy to narrow the spacing between the core cords 30, especially when the five reinforcing core cords 32 are insulating.

[0045] The lower limit of the average interval between adjacent core cords 30 (the distance in the width direction of the toothed belt 1 between the central axes of the core cords 30) is preferably 0.3 mm, more preferably 0.5 mm. On the other hand, the upper limit of the average interval is preferably 4 mm, more preferably 1 mm. If the average interval is less than the lower limit, the insulation between the multiple current-carrying core cords 31 may not be sufficiently ensured, or the flexibility of the toothed belt 1 may be insufficient. Conversely, if the average interval exceeds the upper limit, the toothed belt 1 may become unnecessarily large in the width direction, or the effect of the core cords 30 in improving the strength, durability, driving accuracy, etc. of the toothed belt 1 may be insufficient.

[0046] <Manufacturing method of toothed belts> The toothed belt 1 can be manufactured by a manufacturing method including, for example, an extrusion molding step and a tooth portion forming step.

[0047] (Extrusion molding process) In the extrusion molding step, an extrusion molded body containing a rubber or resin composition as a main component and having the core cord 30 embedded therein is formed by extrusion molding.

[0048] Specifically, the core cords 30 are extruded so as to be covered on both sides with the molten rubber or resin composition while being inserted through a crosshead attached to the tip of the cylinder of an extruder. Alternatively, the molten extruded rubber or resin composition and the core cords 30 may be sandwiched between a pair of rolls and pressurized to embed the core cords 30 in the rubber or resin composition.

[0049] The heating temperature for melting the rubber or resin composition in extrusion molding depends on the type of rubber or resin, whether a curing agent is used, etc., but the lower limit of the heating temperature is preferably 150°C. On the other hand, the upper limit of the heating temperature is preferably 250°C. If the heating temperature is below the lower limit, the rubber or resin composition may not be sufficiently melted, which may make extrusion molding difficult. Conversely, if the heating temperature exceeds the upper limit, the extrusion molded body becomes unnecessarily hot, which may result in an unnecessarily long cooling time and a decrease in the manufacturing efficiency of the toothed belt 1.

[0050] (Tooth formation process) In the toothed portion forming step, the toothed portion 20 is formed on the extrusion molded body after the extrusion molding step, whereby the toothed belt 1 can be obtained.

[0051] Specifically, the tooth portion 20 can be formed, for example, by preparing a cylindrical mold roll having a recess on its outer surface corresponding to the tooth portion 20, and wrapping the extrusion molded body around the mold roll while heating one side of the extrusion molded body.

[0052] The heating temperature in the tooth portion forming step is appropriately determined depending on the temperature at which the extrusion molded body can melt and form the tooth portion 20 on one surface, and the lower limit of the heating temperature is preferably 150°C. On the other hand, the upper limit of the heating temperature is preferably 250°C. If the heating temperature is below the lower limit, the extrusion molded body may not be softened sufficiently, which may make it difficult to form the tooth portion 20. Conversely, if the heating temperature exceeds the upper limit, the entire toothed belt 1 may be easily deformed by heat.

[0053] <Advantages> In the toothed belt 1, the electrical resistance per unit length of the current-carrying core cord 31 is lower than that of the reinforcing core cord 32, so the number of parallel current-carrying core cords 31 required to ensure the electrical resistance required for current flow can be reduced. Furthermore, the toothed belt 1 can maintain its strength mainly through the reinforcing core cord 32. Therefore, the toothed belt 1 can reduce the number of necessary core cords, and therefore can suppress an increase in width while ensuring the number of core cords 30 required for wiring electrical signals and power.

[0054] [Other embodiments] The present invention is not limited to the above-described embodiment, and can be embodied in various other forms in addition to the above-described forms with various modifications and improvements.

[0055] In the above embodiment, the reinforcing core cords 32 and the electrical core cords 31 are alternately arranged in this order from the outside in the width direction, but the arrangement of the electrical core cords 31 and the reinforcing core cords 32 is not limited to this. Several modified examples are described below. Note that in each modified example, components similar to those of the toothed belt 1 shown in Fig. 3 are denoted by the same reference numerals and detailed description thereof is omitted.

[0056] <Variation 1> The toothed belt 2 shown in Figure 4 has 10 core cords 30, each of which has four conductive conductive core cords 31 and six reinforcing core cords 32 having a higher electrical resistance per unit length than the conductive core cords 31.

[0057] In the toothed belt 2, the same number (three on each side) of reinforcing core cords 32 are arranged on both sides in the width direction, and all (four) of the conductive core cords 31 are gathered in the center.

[0058] When the average diameter of the conductive core cords 31 is made larger than the average diameter of the reinforcing core cords 32, arranging these two types of core cords 30 alternately may cause unevenness to easily occur on the surface of the belt body 10 due to the difference in average diameters. By arranging the conductive core cords 31 together in the central portion in this manner, it is possible to reduce the occurrence of the above-mentioned unevenness.

[0059] When the current-carrying core cords 31 are arranged continuously as in the toothed belt 2, it is preferable that the current-carrying core cords 31 have a conductor that is covered with an insulating layer.

[0060] <Variation 2> The toothed belt 3 shown in Figure 5 has 11 core cords 30, each of which has four conductive conductive core cords 31 and seven reinforcing core cords 32 having a higher electrical resistance per unit length than the conductive core cords 31.

[0061] In the toothed belt 3, two conductive core cords 31 run parallel to each other, three reinforcing core cords 32 are arranged between them, and two reinforcing core cords 32 are arranged on each side in the width direction.

[0062] Such a configuration is useful, for example, when two parallel current-carrying core cords 31 are used as the same electric signal or power source. In addition, by distributing the multiple reinforcing core cords 32, the strength of the toothed belt 3 can be easily ensured.

[0063] <Other> In the above embodiments, a specific number of core cords are provided, but the number of core cords is not limited to the number in each embodiment as long as it is three or more.

[0064] Furthermore, the arrangement pattern of the conductive core cords and the reinforcing core cords is not limited to the above-described embodiment, but can be appropriately selected according to the wiring of the necessary electrical signals or power supply.

[0065] In the above embodiment, a case has been described in which the conductive core cord is used as wiring for electrical signals or power, and the reinforcing core cord is used for reinforcement, but there may be conductive core cords that are not used as wiring, and conversely, there may be reinforcing core cords that are used as wiring. [Industrial Applicability]

[0066] The toothed belt of the present invention can suppress an increase in width while ensuring the number of core cords required for wiring electrical signals and power sources. [Explanation of symbols]

[0067] 1, 2, 3 Toothed belt 10 Belt body 20 Teeth 30 core cord 31 Electrical core cord 32 Reinforcing core cord

Claims

1. The belt body, A plurality of teeth are disposed on one surface of the belt body at equal intervals in the longitudinal direction; a plurality of core cords embedded in the belt body along the length direction at intervals in the width direction of the belt body; Equipped with The plurality of core cords are A conductive core cord; A reinforcing core cord having a higher electrical resistance per unit length than the above-mentioned conductive core cord. having A toothed belt in which the average diameter of the current-carrying core cords is larger than the average diameter of the reinforcing core cords.

2. A toothed belt as described in claim 1, wherein an equal number of the reinforcing core cords are arranged on both sides of the width direction, and all of the conductive core cords are gathered in the center.

3. 2. The toothed belt according to claim 1, wherein the two core cords positioned on the outermost sides in the width direction are reinforcing core cords.

4. The plurality of core cords include a plurality of the conductive core cords, 4. The toothed belt according to claim 1, wherein the reinforcing core cord is disposed between adjacent conductive core cords.

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