Drive belt or support belt of high tensile stiffness, in particular for elevator technology

Abstract

A drive system or support system, in particular for elevators, is described, comprising a belt pulley having a diameter of at least 70 mm and a drive belt or support belt which is curved around the belt pulley, wherein the drive belt or support belt comprises a cover layer (1), which is arranged on the lower side of the belt facing toward the belt pulley, and at least one tension layer (2), which is arranged directly above the cover layer; the cover layer is made of a polymeric material having elastic properties, the tension layer contains at least one fiber bundle which is almost unidirectional and which runs in the longitudinal direction of the belt, wherein certain relationships apply between the thickness of the cover layer, the thickness of the tension layer, the diameter of the belt pulley (4) and the Shore A hardness of the cover layer.

Description

[0001] The invention relates to a drive or support system comprising a pulley and a drive or support belt bent around the pulley with high-strength chemical fibers as tension members, and to devices containing the drive or support system.

[0002] Belts play a particularly important role in drive and suspension technology. Such belts, also known as power transmission belts, can be designed as flat belts, V-belts, multi-ribbed belts, toothed belts, or composite ropes.

[0003] US 6,386,324 B1 deals with a tension member for an elevator system that has an aspect ratio of more than one, where the aspect ratio is defined as the ratio of the width w of the tension member to the thickness t (w / t). Increasing the aspect ratio leads to a reduction in the maximum rope compression and increased flexibility compared to conventional elevator ropes.

[0004] WO 2009 / 090299 A1 describes a hoisting machine rope having a width greater than its thickness in a transverse direction of the rope and comprising a load-bearing portion made of a composite material, the composite material comprising non-metallic reinforcing fibers consisting of carbon fibers or glass fibers in a polymer matrix.

[0005] US 2008 / 081724 A1 describes a Power Split Drive (PSD) transmission capable of energy recovery and suitable for use in motor vehicles.

[0006] WO 2012 / 025278 A1 relates to a load pulling system, e.g. elevator system, with at least one belt to which a tensile load is applied, and with at least one deflection device around which the belt is guided.

[0007] Johannes Kunz et al.: "Determining the compressive elastic modulus of elastomers using Shore A hardness", Kunststoffe, Volume 6, June 1, 2006, pages 92 to 94, describes a formula for determining the compressive elastic modulus of elastomers by converting the respective Shore A values.

[0008] In elevator technology, steel cables are the most commonly used suspension element. In recent years, steel cables have been increasingly replaced by belts. However, the load-bearing elements in the belts are also steel cables. Steel cables are generally constructed as cords. In the cord construction, many thin wires are twisted together to form a cord. This gives the steel cables their flexibility.

[0009] The disadvantage of steel cables is their relatively high weight and the increased stretch caused by the cord construction. The cord construction thus achieves high bending flexibility, but also results in undesirably high elasticity and stretch.

[0010] To reduce weight, high-strength synthetic fibers such as aramid, PBO, glass, or carbon fibers are ideal. To avoid structural elongation, the fibers should be arranged parallel to each other as much as possible. Maximum stiffness is achieved when the fibers are arranged almost parallel to each other. However, such parallel fibers exhibit low bending flexibility.

[0011] When such a bundle of fibers is bent, e.g. in elevator technology around a traction pulley, the outer fibers are subjected to tensile stress and the inner fibers to compressive stress. Figur 1c illustrates the tensile and compressive forces that arise during bending. High-strength fibers such as carbon, aramid, or glass are very sensitive to compressive loads and therefore break very easily. Therefore, the use of essentially parallel fiber bundles as tension members, while actually desirable in terms of weight savings and stiffness properties, is difficult when the application requires bending of the fiber bundles.

[0012] The object of the invention was therefore to provide a system in which parallel bundles of fibers are used as tension members, but the compressive load in the fiber bundles during bending is avoided.

[0013] Surprisingly, this challenge was solved by providing the fiber bundle with an additional material layer that exhibits excellent compressive and tensile properties. The cover layer is designed, particularly depending on the required bending radius for the respective application, so that during bending, the compressive load is predominantly in the non-critical cover layer, and the fiber bundle is subjected to only tensile stress.

[0014] The object is therefore achieved by a drive or support system comprising a pulley and a drive or support belt bent around the pulley, wherein the drive or support belt comprises a cover layer arranged on the lower side of the belt facing the pulley, and at least one tension layer arranged directly above the cover layer; the cover layer is formed from a polymeric material with elastic properties, and the tension layer contains at least one almost unidirectional fiber bundle running in the longitudinal direction of the belt, wherein the tension layer is a UD belt, a UD fabric, a UD layer, or a laminate thereof, characterized in that the pulley has a diameter of at least 70 mm, wherein the following relationships apply: a) if 70 mm ≤ d ≤ 200 mm and Sh > 95 Shore A, then b ≥ 1.2 xhb) if 70 mm ≤ d ≤ 200 mm and 90 Shore A ≤ Sh ≤ 95 Shore A, then b ≥ 1.5 xhc) if 70 mm ≤ d ≤ 200 mm and Sh < 90 Shore A, then b ≥ 2 xhd) if 200 mm < d ≤ 500 mm, then 1.5 mm ≤ be) if d > 500 mm, then 2.5 mm ≤ b, where b is the thickness of the cover layer, h is the thickness of the tension layer, d is the diameter of the pulley and Sh is the Shore A hardness of the cover layer.

[0015] The belt exhibits high tensile stiffness. The arrangement according to the invention optimally utilizes the stiffness of the fiber bundles in the tensile layer in the drive or suspension belt. The tensile-stiff belt can be bent around the pulley with little or no compressive loads in the fiber bundles. This significantly improves the stability of the belt. This allows the belt to be used in drive or lifting devices, and especially in elevator systems. The invention is explained in detail below.

[0016] The drive or support belt is also referred to simply as a belt in this application. The belt can be a closed belt, but is preferably an open belt. The belt can be of any length, depending on the specific application.

[0017] The pulley has a diameter of at least 70 mm. Any standard pulley can be used. It can be, for example, a deflection pulley or a drive pulley. The drive pulley is preferably a traction pulley.

[0018] The drive or support belt can be bent around the pulley with any desired wrap angle, e.g. with a wrap angle of 90° to 270° on the drive or support belt, in particular on the traction pulley.

[0019] The drive or carrying belt comprises a cover layer and at least one tension layer.

[0020] The cover layer is arranged at least on the lower side of the belt facing the pulley, i.e. it forms the running surface or the contact surface to the pulley.

[0021] The elasticity of the cover layer is achieved by forming the cover layer from a polymeric material with elastic properties. The polymeric material with elastic properties is preferably one or more elastomers or thermoplastic elastomers.

[0022] The polymeric material with elastic properties for the cover layer is preferably made of rubber and / or a polyurethane, with polyurethane being particularly preferred.

[0023] Specific examples of polymeric materials with elastic properties, particularly elastomers or thermoplastic elastomers, are ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), partially hydrogenated or hydrogenated nitrile rubber (HNBR), fluororubber (FKM), natural rubber (NR), chloroprene rubber (CR), styrene-butadiene rubber (SBR), butadiene rubber (BR), or polyurethane (PU), which are available unblended or blended with at least one other rubber component, particularly with one of the aforementioned rubber types, for example in the form of an EPM / EPDM or SBR / BR blend. HNBR, EPM, EPDM, PU, ​​or an EPM / EPDM blend are particularly important.

[0024] The cover layer is preferably a polyurethane, whereby the polyurethane can be an elastomer or a thermoplastic elastomer. The polyurethane is preferably obtained by crosslinking a polyurethane prepolymer with a crosslinker or crosslinker system. Polyurethane prepolymers can be formed by reacting polyols with polyisocyanates. By selecting the polyols and polyisocyanates used, polyurethane prepolymers with different properties can be obtained as required. Examples of suitable polyols are polyester polyols, polycarbonate polyols, and polyether polyols. Examples of polyisocyanates are, in particular, diisocyanates such as para-phenylene diisocyanate and 4,4'-methylenediphenyl diisocyanate. Crosslinkers for polyurethane prepolymers are known to the person skilled in the art and also include chain extenders. Examples of crosslinkers are diamines and diols such as 1,4-butanediol.

[0025] The polymeric material with elastic properties for the cover layer may optionally contain one or more additives commonly used in the field. Examples include fillers, processing aids, plasticizers, anti-aging agents, and optionally other additives, such as fibers, especially short fibers, for reinforcement and color pigments. The optional additives can be added to the starting components—i.e., the uncrosslinked rubber or polyurethane prepolymer and the crosslinker or crosslinker system—before or during crosslinking. In this regard, reference is made to the general state of rubber compounding technology.

[0026] The hardness of the top layer can vary widely and can be adjusted depending on the application. The Shore A hardness of the top layer can, for example, range from 80 to 99, preferably from 90 to 96. The Shore A hardness is determined according to DIN 53505 at 23°C.

[0027] The drive or support belt further comprises at least one tensile layer containing at least one nearly unidirectional fiber bundle extending in the longitudinal direction of the belt. The at least one fiber bundle is the tensile member.

[0028] A nearly unidirectional fiber bundle is a bundle of fibers arranged essentially parallel to each other. The fibers are preferably long fibers. A bundle of long fibers arranged essentially parallel is also called a roving. It is understood that an ideal arrangement is generally not achieved in technical systems such as fiber bundles. Nearly unidirectional fiber bundles are often simply referred to as unidirectional fiber bundles.

[0029] The at least one nearly unidirectional fiber bundle in the tensile layer can be fixed to substrates such as plastic films or paper, threads, and / or plastic, or embedded in a plastic. The at least one nearly unidirectional fiber bundle is preferably flat. Such nearly unidirectional fiber bundles are commercially available, e.g., as UD tapes, UD scrims, or UD layers.

[0030] UD is the abbreviation for unidirectional. UD tapes and UD scrims are also referred to as UD fiber tapes or UD fiber scrims and essentially contain parallel-arranged long fibers, which may be fixed to substrates such as plastic films or paper, threads, and / or plastic. UD scrims can be held together, for example, by paper or thread stitching. UD layers are fiber-reinforced plastics in which essentially parallel-arranged long fibers are embedded in a plastic.

[0031] Two or more UD tapes, UD fabrics, or UD layers can be laminated on top of each other if necessary to form larger composites. In the laminates, the respective tapes, fabrics, or layers are arranged in such a way that the nearly unidirectional fiber bundles are aligned in the same direction in the longitudinal direction.

[0032] Suitable plastics for fixing or embedding the almost unidirectional fiber bundles are thermoplastics, thermosetting plastics such as epoxy resins, phenol-formalaldehyde resins or polyurethanes, and elastomeric plastics such as rubbers or polyurethanes.

[0033] The tensile layer containing at least one nearly unidirectional fiber bundle is a UD tape, a UD scrim, a UD layer or a laminate thereof.

[0034] The fibers in the fiber bundle can be synthetic fibers, such as carbon fibers, glass fibers, polymer fibers, or basalt fibers. They can also be hybrid fiber bundles, which contain two or more fibers made of different materials.

[0035] The fibers of the fiber bundle are made, for example, of carbon, glass, polybenzoxazole, aramid, basalt, polyamide (PA), polyester, polyetheretherketone (PEEK), polyethylene terephthalate (PET), or polyethylene-2,6-naphthalate (PEN), or at least two of these fibers, with carbon fibers, aramid fibers, polybenzoxazole fibers, glass fibers, and basalt fibers, or at least two of these fibers, being preferred. Particular preference is given to nearly unidirectional fiber bundles made of carbon fibers and nearly unidirectional hybrid fiber bundles made of carbon fibers and at least one other of the above-mentioned fibers, e.g., hybrid fiber bundles made of carbon fibers and glass fibers.

[0036] The thickness of the tensile layer can vary within a wide range, for example, depending on the fiber material used, the diameter of the pulley, and the intended application. The tensile layer can, for example, have a thickness h in the range from 0.1 to 10 mm, preferably from 0.5 to 5 mm. The width of the tensile layer can vary within a wide range, particularly depending on whether only one continuous tensile layer or two or more tensile layers arranged next to one another are used. The tensile layer can, for example, have a width in the range from 5 to 100 mm, preferably from 10 to 30 mm. Preference is given to using one tensile layer or, for example, two to 10 tensile layers arranged next to one another and optionally spaced apart.

[0037] To avoid or significantly reduce compressive stress on the fiber bundles during belt use, the cover layer thickness is adjusted depending on the specific conditions. The thickness of the tensile layer, the material properties, especially the hardness, of the cover layer, and the smallest bending diameter determine the thickness of the cover layer.

[0038] The following geometric relationships have proven to be optimal for the belt depending on the pulley diameter and apply to the drive and support system according to the invention, where b is the thickness of the cover layer and h is the thickness of the tension layer: A) For a pulley diameter of 70 to 200 mm: for a cover layer with a hardness of > 95 Shore A the following applies: b ≥ 1.2 xh for a cover layer with a hardness of 90 to 95 Shore A the following applies: b ≥ 1.5 xh for a cover layer with a hardness of < 90 Shore A the following applies: b ≥ 2 xh B) For a pulley diameter of greater than 200 mm up to 500 mm the thickness of the cover layer is b ≥ 1.5 mm. C) For a pulley diameter of over 500 mm the thickness of the cover layer is b ≥ 2.5 mm.

[0039] For relationships A), B) and C), the cover layer can theoretically be significantly thicker than the minimum thickness required according to these relationships, but from a technical point of view this is not sensible or necessary. By way of example only, taking into account the above relationships A) to C), the thickness of the cover layer b can, for example, be in the range of 0.2 to 1.5 mm for a pulley diameter d of 70 to 200 mm, in the range of 1.5 to 3 mm for a pulley diameter d of more than 200 to 500 mm, and in the range of 2.5 to 5 mm for a pulley diameter d of more than 500 mm. However, greater layer thicknesses are certainly possible.

[0040] The drive or suspension belt can consist of only the cover layer and the tension layer. In this embodiment, the cover layer is applied to one side of the tension layer, such as a U-belt, to form the belt. Details of the manufacturing process are explained below. The cover layer and the tension layer combine to form the belt.

[0041] In a preferred embodiment, the drive or support belt has a belt body comprising a belt backing made of a polymeric material with elastic properties and the cover layer. The tension layer can be sandwiched between the cover layer and the belt backing. The tension layer is preferably embedded in the belt body.

[0042] The same polymeric materials with elastic properties described above for the cover layer can be used as the polymeric material with elastic properties for the belt backing. Therefore, reference is made to the above information on the polymeric material with elastic properties, including preferred examples, additives, and hardness. The belt backing is also preferably made of polyurethane.

[0043] The belt backing and the cover layer can be formed from the same or a different polymeric material. In a preferred embodiment, they are formed from the same polymeric material with elastic properties.

[0044] In a special embodiment, the belt back can be designed such that, on the side of the belt opposite the cover layer, it forms an upper cover layer on the tensile layer, for which the relationships a) to e) or A) to C) mentioned above for the cover layer also apply. The two cover layers can be the same or different in terms of polymer material, hardness and / or layer thickness. In this way, the belt can be used on both sides as a running surface for the same or for different pulleys. In one embodiment, the belt is designed symmetrically, i.e. it has a cover layer as defined above both below and above the tensile layer, wherein both cover layers are made of the same material and have the same thickness.

[0045] The tension layer runs continuously in the longitudinal direction of the belt. In the transverse direction of the drive or support belt, the tension layer can be arranged continuously across the entire belt width or part of the belt width. It is also possible for two or more tension layers to be arranged side by side in the transverse direction of the drive or support belt, with them being at the same height in the thickness direction. These can also be spaced apart from each other in the transverse direction, so that there can be open areas between the individual tension layers or areas filled with the belt backing on the cover layer.

[0046] The application of the cover layer and, if applicable, the belt backing to the at least one tensile layer or the preferred embedding of the at least one tensile layer in the belt body comprising the cover layer and the belt backing can be carried out in a conventional manner known to those skilled in the art, e.g., by extrusion or casting, with extrusion being preferred. In a preferred embodiment, the at least one tensile layer is embedded in a polymeric material by casting or extrusion, with the polymeric material forming the belt body comprising the cover layer and the belt backing. The cover layer and the belt backing are then formed from the same polymeric material with elastic properties.

[0047] For example, a thermoplastic elastomer, which may contain additives as described above, can be converted into a melt by heating. The melt can then be applied to the at least one tensile layer by extrusion or casting, or the at least one tensile layer can be embedded in the melt by extrusion or casting. After cooling, the belt is obtained.

[0048] The drive or support belt is preferably a flat belt. The belt preferably has a rectangular cross-section, with the drive or support belt having, for example, a width in the range of 10 to 120 mm, preferably 15 to 80 mm, and a thickness in the range of 1 to 12 mm, preferably 1.5 to 8 mm. The aspect ratio, ie, the ratio of width to thickness, of the belt is preferably in the range of 5 to 30. The belt is preferably a drive belt.

[0049] The invention also relates to a device comprising a drive or support system as described above. The device is preferably a drive and / or lifting device and in particular an elevator system.

[0050] The belt described above is generally suitable for applications in drive technology and lifting technology.

[0051] The invention will now be further explained using exemplary embodiments with reference to schematic drawings. They show: Fig. 1a-c shows a unidirectional fiber bundle in longitudinal section; Fig. 2 shows a curved belt for the drive or support system according to the invention in longitudinal section; Fig. 3 shows a belt bent around a pulley for the drive or support system according to the invention in longitudinal section; Fig. 4a-b shows two embodiments of a belt for the drive or support system according to the invention in cross section.

[0052] Fig. 1a shows a unidirectional fiber bundle in longitudinal section without stress. Fig. 1b shows the unidirectional fiber bundle in longitudinal section under tensile stress in the longitudinal direction and the resulting tensile forces. Fig. 1c shows the unidirectional fiber bundle in longitudinal section in a bent state and the tensile and compressive loads that occur.

[0053] Fig. 2 shows in longitudinal section a belt used according to the invention with a cover layer 1 with a thickness b and a tensile layer 2 with a thickness h in a bent state and the tensile and compressive forces occurring.

[0054] Fig. 3 shows in longitudinal section a drive or support system according to the invention, in which a belt with a cover layer 1 with a thickness b, a tension layer 2 with a thickness h and a belt back 3 is bent around a pulley 4.

[0055] In an exemplary concrete embodiment, which is not intended to limit the scope of the invention in any way, according to Fig. 3 The cover layer 1 with a thickness of 1.15 mm and the belt back 3 as a complete unit form a belt body made of a polyurethane elastomer with a Shore A hardness of 92 Shore A. The tensile layer 2 is embedded in the belt body. The tensile layer 2 is a UD carbon fiber band with a thickness of 0.7 mm. The belt is a flat belt with a width of approximately 30 mm and a thickness of approximately 3 mm. The pulley is a traction pulley with a diameter of approximately 100 mm. This embodiment is suitable, for example, as a traction system for an elevator system.

[0056] In the Fig. 4a-b A belt is shown in cross-section in two alternative embodiments, in which one or three tension layers 2 are embedded in a belt body 5. The belt body 5 is formed from a cover layer 1 and a belt back 3. This can be the Fig. 3 shown belts. In Fig. 4a a tension layer 2 is embedded in the belt body 5. Fig. 4b shows an embodiment in which three tension layers 2 are arranged transversely next to each other and spaced apart from each other. The resulting space is filled by the belt body 5. The three tension layers are arranged at the same height. Fig. 4a und 4b show a symmetrical embodiment in which both sides of the belt are designed as a cover layer. Bezugszeichenliste

[0057] 1Belt cover layer 2Belt cover 3Belt back of the belt 4Pulley 5Belt body

Claims

1. Drive system or suspension system comprising a belt pulley and a drive belt or suspension belt inflected about the belt pulley, wherein the drive belt or suspension belt comprises an outer layer arranged on the lower side of the belt facing the belt pulley and at least one tension element arranged directly above the outer layer, the outer layer is composed of a polymeric material having elastic properties, and the tension element comprises at least one virtually unidirectional fibre bundle running in longitudinal direction of the belt, where the tension element is a UD belt, a UD scrim, a UD layer or a laminate thereof, characterized in that the belt pulley has a diameter of at least 70 mm, where the following relationships apply: a) when 70 mm ≤ d ≤ 200 mm and Sh > 95 Shore A, b ≥ 1.2 x h b) when 70 mm ≤ d ≤ 200 mm and 90 Shore A ≤ Sh ≤ 95 Shore A, b ≥ 1.5 x h c) when 70 mm ≤ d ≤ 200 mm and Sh < 90 Shore A, b ≥ 2 x h d) when 200 mm < ≤ 500 mm, 1.5 mm ≤ b e) when d > 500 mm, 2.5 mm ≤ b, in which b is the thickness of the outer layer, h is the thickness of the tension element, d is the diameter of the belt pulley and Sh is the Shore A hardness of the outer layer.

2. Drive system or suspension system according to Claim 1, characterized in that the belt pulley is a traction pulley.

3. Drive system or suspension system according to Claim 1 or Claim 2, characterized in that the drive belt or suspension belt has a belt body comprising a belt backing composed of a polymeric material having elastic properties and the outer layer, with the tension element preferably embedded in the belt body.

4. Drive system or suspension system according to Claim 3, characterized in that the belt backing and the outer layer are formed from the same or different polymeric materials.

5. Drive system or suspension system according to any one of Claims 1 to 4, characterized in that the thickness h of the tension element is in the range from 0.1 to 10 mm.

6. Drive system or suspension system according to any one of Claims 1 to 5, characterized in that the fibres of the fibre bundle are composed of carbon, glass, polybenzoxazole, aramid, basalt, polyamide, polyester, polyetheretherketone, polyethylene terephthalate or polyethylene 2,6-naphthalate or at least two of these fibres, preference being given to carbon fibres, aramid fibres, polybenzoxazole fibres, glass fibres and basalt fibres, and particular preference to carbon fibres.

7. Drive system or suspension system according to any one of Claims 1 to 6, characterized in that the outer layer is formed from a rubber and / or a polyurethane, preference being given to polyurethane.

8. Drive system or suspension system according to any one of Claims 1 to 7, characterized in that the tension element is a UD belt or a laminate thereof.

9. Drive system or suspension system according to any one of Claims 1 to 8, characterized in that a tension element is arranged across the entire belt width or part of the belt width in transverse direction of the drive belt or suspension belt, or two or more tension elements are arranged alongside one another in transverse direction of the drive belt or suspension belt.

10. Drive system or suspension system according to any one of Claims 1 to 9, characterized in that the drive belt or suspension belt is a flat belt.

11. Drive system or suspension system according to any one of Claims 1 to 10, characterized in that the drive belt or suspension belt has a rectangular cross section, preferably having a width in the range from 15 to 80 mm and a thickness in the range from 1.5 to 8 mm.

12. Device comprising a drive system or suspension system according to any one of Claims 1 to 11.

13. Device according to Claim 12, wherein the device is a drive device and / or lifting device.

14. Device according to Claim 12 or 13, wherein the device is a lift system.

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