Method and device for producing drive belts with profiles formed on both sides, in particular double-sided toothed belts

Abstract

Method for producing drive belts (20) with profiles formed on both sides, in particular double toothed belts, in which a) a drum-shaped belt forming roller (5) provided on the outside with a negative form (5a) for the internal profiling of the drive belt (20), in particular with a negative form (5a) for the internal toothing of a double toothed belt, is first provided with a tubular drive belt blank, which, starting from the belt forming roller (5), is gradually built up from i) a fabric stocking (9) pulled over the belt forming roller (5), ii) tension cords wound over them as reinforcing elements, iii) a rubber layer / rubber plate placed thereon and (iv) a further layer of fabric material (9), b) the belt forming roller (5) with the tubular blank is positioned within a flexible forming belt forming an endless loop, a so-called forming belt loop (3), which is designed on its inner side (3a) facing the belt forming roller (5) as a negative mold for the external profiling of a drive belt (20), wherein the forming belt loop (3) rolls on a partial circle (5b) of the outer circumference of the belt forming roller (5) provided with the blank and is guided and synchronized with guide elements (4) arranged on the end faces of the belt forming roller (5), c) the forming belt loop (3) has a length which is greater than the unwound outer circumference of the belt forming roll (5) or the blank, d) the belt forming roller (5) is heated on the inside during the production of the drive belt (20) so that the blank is continuously heated for gradual forming and vulcanisation, e) the forming belt loop (3) cooperates on its outer side in the region of rolling on the pitch circle of the belt forming roller (5) with support elements (1) which are arranged pivotably and flexibly on a carrier belt (7) partially encircling the belt forming roller (5) and the forming belt loop (3), and wherein the forming belt loop (3) is pressed onto the belt forming roller (5) by the carrier belt (7) with the aid of deflection and tensioning rollers (2, 6, 8) acting on the carrier belt (7) in such a way that in the region of rolling on the pitch circle (5b) a rotating shaping and vulcanisation mould (30) which changes in volume is formed in the rolling area, so that over several revolutions i) initially and with increasing heating, the tubular blank is formed between the outer negative mold (5a) of the belt forming roller (5) and the inner (3a) negative mold of the forming belt loop (3) with its two-sided profiling in such a way that the tensile strands / reinforcing elements of the blank are penetrated by the material of the applied rubber layer, ii) then, with further heat supply and with further circulation of the forming belt loop (3) pressed on by the carrier belt (7) and the supporting bodies, the blank formed into the drive belt (20) profiled on both sides is vulcanized.

Description

[0001] The invention relates to a method and a device for producing drive belts with profiles formed on both sides, such as toothed belts, wedges or V-ribbed belts, in particular to a method and a device for producing double toothed belts.

[0002] Various manufacturing processes are known for producing single-sided toothed drive belts. DE 39 31 480 A1 and JP 2007-85 452 A relate to a process for producing single-sided toothed belts. The base material of the belt is applied via an extruder nozzle between a rotating forming wheel and a forming belt.

[0003] A similar method for producing a single-sided toothed belt is known from DE 35 27 640 A1, wherein the toothed belt is made of two partial belts.

[0004] Several manufacturing processes are known for the production of double-sided rubber timing belts, namely, on the one hand, section-by-section production in a double press and, on the other hand, production in a vulcanization mold, which essentially consists of a segmented outer mold and a drum- or torus-like fixed inner mold, whereby the outer segments are pressed together to their stop by external pressure and thus create the external toothing of the timing belt, while the internal toothing is formed via the fixed inner toothed drum.

[0005] Such a segment mold for the production of double toothed belts is disclosed, for example, in DE 25 17 430 A1, in which the segment mold is formed from two parts, namely a mandrel provided with teeth on its outer surface, and a series of externally acting toothed segments that can be moved towards the mandrel.

[0006] The disadvantage of such molds is that they can only produce one belt dimension at a time, i.e., a belt with a specific number of teeth, since the segments must be perfectly flush in their final position. Thus, a separate mold is required for each individual belt dimension. Furthermore, there is always the risk of material leakage at the joints of the segments, which leads to irregularities in the external toothing.

[0007] Another known device for the production of double-sided rubber timing belts comprises a drum- or torus-shaped mold for producing the internal teeth of the belt and a milling machine. The torus-shaped mold or mandrel is formed with teeth on its outer surface, on which a sleeve is formed by assembling the various elements constituting the belt and consisting of a deformable sheath. Using this mold, it is possible to obtain a fully vulcanized belt with teeth on its inner surface and a layer of elastomeric material / rubber layer on its outer surface. The rubber layer present on the outer surface of the belt is treated with the milling machine, which cuts teeth into this rubber layer to produce the external teeth.Here, too, only one belt dimension, i.e. a belt with a specific number of belt teeth, can be produced. This process is extremely complex due to the milling, i.e. the removal of teeth, and requires considerable precautions to collect the milled-off material.

[0008] The object of the invention was therefore to provide a method and a device with which drive belts with profiles formed on both sides, in particular double-sided timing belts of various belt dimensions, i.e., with different numbers of belt teeth, can be produced in a simple manner. The forming of a double-sided profiled drive belt or double-sided timing belt can take place in a single step, eliminating the need for material to escape at joints or to collect material removed from other processes. Furthermore, the object was to design such a method and the associated device as cost-effectively as possible.

[0009] This object is achieved by a method having the features of the main claim, by a device having the features of claim 5, and by a method having the features of claim 8. Further advantageous embodiments are disclosed in the respective subclaims.

[0010] In this case, a drum-shaped belt forming roller, which is provided on the outside with a negative form for the internal profiling of the drive belt, in particular with a negative form for the internal toothing of a double toothed belt, is first provided with a tubular drive belt blank, which, starting from the belt forming roller, is gradually built up from i) a fabric stocking pulled over the belt forming roller, ii) tension cords wound over them as reinforcing elements iii) a rubber layer / rubber plate placed thereon and iv) a further layer of fabric material,

[0011] The belt forming roll is then positioned with the tubular blank within a flexible forming belt, a so-called forming belt loop, which forms an endless loop and which is designed on its side facing the belt forming roll as a negative form for the external profiling (back profiling) of a drive belt, wherein the forming belt loop rolls on a pitch circle of the outer circumference of the belt forming roll provided with the blank and is guided and synchronized in a circumferentially positioned manner by guide elements arranged on the end faces of the belt forming roll. The forming belt loop has a length which is greater than the unwound outer circumference of the belt forming roll or the blank.

[0012] During the production of the drive belt, the belt forming roller is heated on the inside so that the blank is continuously heated for gradual forming and vulcanization.

[0013] On its outer side, in the rolling area on the pitch circle of the belt forming roller, the forming belt loop interacts with support elements that are pivotably and flexibly arranged on a carrier belt that partially encircles the belt forming roller and the forming belt loop. Thus, the forming belt loop is pressed onto the belt forming roller by the carrier belt with the aid of deflection and tensioning rollers acting on the carrier belt in such a way that a "circumferential shaping and vulcanization mold" of varying volume is formed in the rolling area on the pitch circle. This means that a volume-variable space or distance is formed between the belt forming roller and the forming belt loop in the rolling area, i.e., across the pitch circle of the rolling.

[0014] In this way, over several cycles, initially and with increasing heating, the tubular blank is formed between the outer negative form of the belt forming roller and the inner negative form of the forming belt loop with its two-sided profiling in such a way that the tensile strands / reinforcing elements of the blank are penetrated by the material of the applied rubber layer.

[0015] However, the inner and outer fabric layers are not penetrated, or at least only insignificantly, i.e., neither the fabric stocking pulled over the belt forming roller at the beginning of the process nor the additional layer of fabric material applied to the outside of the blank. This is achieved by appropriately developing the fabric density so that, as in the conventional process, the fabric in the tooth area is stretched and "pushed" forward by the warm-flowing rubber compound.

[0016] The blank formed into a drive belt profiled on both sides is then completely vulcanized under further heat application and with further circulation of the forming belt loop pressed on by the carrier belt and the support bodies.

[0017] With the method according to the invention, different belt dimensions, ie belts with different numbers of teeth, can be manufactured in a single manufacturing process and on a single device, wherein the profiling on both sides can be formed in one step, in one manufacturing stage.

[0018] An advantageous development of the process is that the shaping of the double-sided profiling of the tubular blank, which takes place over several cycles, takes place while heating the blank to a temperature of 110°C and at a rotation speed that is higher than that during the subsequent vulcanization. At this temperature, the rubber material has sufficient flowability without excessive vulcanization, i.e., cross-linking of the individual rubber components, occurring. In conjunction with the pressure applied for profiling, this also allows for easy penetration of the reinforcements, while preventing penetration of the fabric layers on the surfaces of the subsequent blank.

[0019] A further advantageous embodiment consists in that the vulcanisation of the formed blank, which takes place over a number of cycles, takes place when the blank is heated to a temperature of 180° C and at a rotational speed which is lower than during the preceding shaping. In particular, in conjunction with a further advantageous embodiment, which consists in the pressure exerted on the belt forming roller by means of deflection and tensioning rollers acting on the carrier belt being maintained during the shaping process and subsequently at least during the first 15% of the vulcanisation phase, e.g. the planned number of vulcanisation cycles, this results in a continuous transition from the shaping step (shaping cycles) carried out when the material is still flowable to the volume-constant, oralmost volume-constant vulcanization (vulcanization cycles) of the double-sided profiled drive belt and thus on the fixing of the final achieved shape.

[0020] The device according to the invention for carrying out the method comprises a drum-shaped belt forming roller which is mounted in a machine frame so as to be rotatable on at least one side and which is provided on the outside with a negative mold for the internal profiling of a drive belt, in particular with a negative mold for the internal toothing of a double-toothed belt. A flexible forming belt surrounds the belt forming roller in the form of an endless loop, hereinafter referred to as the forming belt loop. The forming belt loop, or thus the forming belt, is designed on its inner side facing the belt forming roller as a negative mold for the external profiling / back profiling of a drive belt, wherein the forming belt loop rolls on a pitch circle of the outer circumference of the belt forming roller, enclosing a drive belt blank applied to the belt forming roller and forming a circumferential vulcanization mold or vulcanization volume whose volume changes in the rolling area.

[0021] The forming belt loop is guided circumferentially by guide elements arranged on the end faces of the belt forming roll and synchronized with the rotation of the drum-shaped belt forming roll. The forming belt loop has a length that is greater than the unwound circumference / outer circumference of the belt forming roll or the blank.

[0022] The device further comprises a carrier belt for supporting and reinforcing the forming belt, with pivoting and flexibly arranged support elements arranged on one side of the carrier belt. With its support elements, the carrier belt supports the forming belt loop on its rear side facing away from the belt forming roller, across the pitch circle over which the forming belt loop rolls along the outer circumference of the belt forming roller.

[0023] For this purpose, the device is provided with deflection rollers for the carrier belt arranged at a distance on both sides of the drum-shaped belt forming roller, as well as at least one further tensioning roller acting on the carrier belt and applying a tensile force, whereby the forming belt loop is pressed onto the pitch circle of the belt forming roller via the carrier belt and the support elements in the rolling area.

[0024] An advantageous design of the device is that the forming belt loop is designed as a flexible metal corrugated belt in a profile shape, i.e., as a thin, profiled or corrugated metal belt, with the support elements on the carrier belt configured to match the shape of the metal belt. This results in a particularly lightweight and durable device capable of producing a large number of double-sided timing belts. Such a profiled metal belt as a forming belt loop can be formed with high precision using pressing tools, is relatively thin and very flexible, and, thanks to its heat resistance, is also well suited for forming and vulcanizing the double-sided profiled timing belt.

[0025] A further advantageous design, because it is particularly easy to provide, is that the forming belt loop is designed as a vulcanized toothed belt containing the negative mold for the external profiling of the drive belt to be produced, i.e. as a so-called counter-profile belt.

[0026] A further advantageous design is that the guide elements are designed as toothed flanges or wheel flanges that engage with the negative mold of the forming belt loop. Such a toothed flange or wheel flange are very easy to manufacture machine elements and can be easily attached and fastened to the sides of the forming roller. The resulting engagement of the forming belt loop allows for reliable synchronization. The forming belt loop runs and is guided, like a toothed belt and pulley in a toothed belt drive, on the wheel flanges on both sides of the drum-shaped belt forming roller, with a certain distance from the surface toothing of the drum-shaped belt forming roller, namely the forming or vulcanization distance described above.

[0027] The invention will be explained in more detail using an exemplary embodiment in connection with the device according to the invention. Fig. 1 a device according to the invention as a schematic diagram in perspective view Fig. 2 the device according to the invention according to Fig. 1 in a front view Fig. 3 the engagement conditions of the rotating shaping and vulcanization elements of a device according to the invention according to Fig. 1 Fig. 4 an enlarged view of the engagement conditions of the rotating shaping and vulcanization elements of a device according to the invention according to Fig. 1 Fig. 5 a further enlarged view of the engagement conditions on a single double profile tooth of the rotating shaping and vulcanization elements of a device according to the invention according to Fig. 1

[0028] The Fig. 1 shows a drum-shaped belt forming roller 5 mounted in a machine frame so as to be rotatable on at least one side, which is provided on the outside with a negative mold 5a for the internal profiling of a double-toothed belt. A flexible forming belt surrounds the belt forming roller 5 in the form of an endless forming belt loop 3. The forming belt loop 3 is designed on its inner side 3a facing the belt forming roller as a negative mold for the external profiling / back profiling of a drive belt 20, wherein the forming belt loop rolls on a pitch circle 5b of the outer circumference of the belt forming roller, enclosing a drive belt blank applied to the belt forming roller 5 and forming a circumferential vulcanization mold or vulcanization volume 30 whose volume changes in the rolling area.

[0029] The forming belt loop 3 is circumferentially guided by guide elements arranged on the end faces of the belt forming roller and designed as toothed flanges 4, and is synchronized with the rotation of the drum-shaped belt forming roller 5. The forming belt loop 3 has a length that is greater than the unwound circumference / outer circumference of the belt forming roller 5 or the blank of the drive belt 20.

[0030] The device further comprises a carrier belt 7 serving to support and reinforce the forming belt, with tooth-shaped support elements 1 provided on one side of the carrier belt, which are pivotably and flexibly arranged and complementary to the profile of the forming belt loop. With these support elements 1, the carrier belt supports the forming belt loop 3 via the partial circle 5b, over which the forming belt loop rolls on the outer circumference of the belt forming roller, on its rear side facing away from the belt forming roller 5.

[0031] For this purpose, the device is provided with deflection rollers 2 for the carrier belt, arranged at a distance from one another on both sides of the drum-shaped belt forming roller 5, as well as at least one further tensioning roller 8 acting on the carrier belt and applying a tensile force, whereby the forming belt loop 3 is pressed onto the pitch circle 5b of the belt forming roller 5 via the carrier belt and the support elements 1 in the rolling area.

[0032] The largely conventional belt forming roller 5 in the form of a drum is covered with a fabric stocking according to the known construction method, spirally wound with tension cords, and then covered with a rubber plate / rubber layer. Finally, another toothed fabric is applied. As shown in the overview of the Fig. 1 and Fig. As illustrated in Figure 2, the thus prepared belt forming roller 5 is then provided on both sides with a guide element designed as toothed flanges 4. A forming belt loop 3 made of high-strength, flexible steel with a very thin wall thickness in the range of 0.1 to 0.25 mm, preformed with the profile of the external toothing to be produced, is placed around the mold, whereby the endlessly closed steel belt contains significantly more belt teeth than the belt forming roller 5 on its outer circumference.

[0033] After the prepared belt forming roller 5 has been inserted between the two deflection rollers 2 and 6, the steel belt comes into contact with the support elements 1 designed as toothed segments, which are fastened to a carrier belt 7 that wraps around the deflection rollers 2 and 6 as well as the tensioning roller 8. The synchronous "tracking" of the support elements 1 designed as toothed segments into the corresponding recesses of the steel belt or the forming belt loop 3 is ensured by the toothed flanges 4 on both sides. This is clearly shown in the Fig. 3, which allows the tooth segments 1 to mesh with the toothed flanges 4 on both sides and the steel strip 3 can be easily removed.

[0034] After this preparatory work, the linearly movable tension roller 8 builds up a process pressure through the carrier belt 7 and the support elements 1 designed as toothed segments via the steel belt or the forming belt loop 3 onto the rubber compound of the rubber plate, which leads to the single-stage forming of the final product. During the production process and the vulcanization time, the belt forming roller 5 with the flanged wheels 4 and the steel belt or the forming belt loop 3 rotate and thus roll on the rotating carrier belt 7 with the toothed segments / support elements 1. The belt forming roller 5, also called toothed belt form, is heated from the inside during the production process, while the toothed segments / support elements 1 are protected from strong cooling by an external insulation not shown in detail here and from the Fig. 3 recognizable inlet E into the steel strip or the forming strip loop 3 are preheated by a radiant heater, also not shown in detail here.

[0035] As can be seen from the combined view of the figures, this device can be used to accommodate timing belt forms or belt forming rollers 5 with different diameters and thus different numbers of belt teeth, provided the distance between the deflection rollers 2 and 6 is variable within certain limits. The steel belt or the forming belt loop 3 must also be provided with a sufficiently high number of teeth to enable force-free insertion / insertion over belt forming rollers of different diameters.

[0036] As in particular Fig. 4 shows, the belt forming roller 5 and the steel belt or the forming belt loop 3, fixed and pressed by the support elements 1 designed as tooth segments and on the carrier belt 7, form a common intermediate space which, as a forming and vulcanization volume 30, gives the double toothed belt to be manufactured its shape in one step and at the same time is kept under pressure permanently during the vulcanization by the pre-tensioning of the carrier belt 7 via the tensioning roller 8.

[0037] In connection with the Fig. 4 and Fig.5 shows that the outside of the double-sided timing belt to be manufactured consists of fabric 9 on both sides. The tensile strand 11, which is wound spirally onto the fabric 9 on the belt forming roller 5 in preparation for the process, has the rubber mixture flow through it under pressure, and the tooth bodies 10 of the double-timing belt are formed. The forming pressure is transferred to the product via the support elements 1 designed as tooth segments and the steel belt or the forming belt loop 3. The steel belt bridges the gap between the tooth segments and thus reliably prevents material from escaping between the tooth segments. Since this forming pressure can be steadily built up by the tension roller 8 over the period of several revolutions of the belt forming roller 5 in the device, a controlled, single-stage tooth forming takes place at optimal flow temperatures before the actual vulcanization process begins. List of reference symbols 1 support element 2 pulleys 3 forming tape loops 3a Inside of the forming band loop 4 Toothed flanged disc 5 Belt forming roller 5a Negative mold for the inner profiling of a double timing belt 5b Pitch circle of the belt forming roller 6 pulley 7 Carrier tape 8 tension pulley 9 fabrics 10 tooth bodies 11 Tension cord 20 drive belts or double toothed belts 30 Vulcanization form or vulcanization volume

Claims

[1] Method for manufacturing drive belts (20) with profiling formed on both sides, in particular double toothed belts, wherein a) a drum-shaped belt forming roller (5) provided on its outer side with a negative mold (5a) for the inner profiling of the drive belt (20), in particular with a negative mold (5a) for the inner toothing of a double toothed belt, is first provided with a tubular drive belt blank, which, starting from the belt forming roller (5), is built up step by step from i) a fabric stocking (9) pulled over the belt forming roller (5), ii) coiled traction strands as reinforcing elements, iii) a rubber layer / rubber sheet placed on top of it and iv) a further layer of tissue material (9), b) the belt forming roller (5) with the tubular blank is positioned within a flexible forming band, a so-called forming band loop (3), which forms an endless loop and which is designed on its inner side (3a) facing the belt forming roller (5) as a negative mold for the outer profiling of a drive belt (20), wherein the forming band loop (3) rolls on a pitch circle (5b) of the outer circumference of the belt forming roller (5) provided with the blank and is guided circumferentially and synchronized by guide elements (4) arranged on the end faces of the belt forming roller (5), c) the forming belt loop (3) has a length that is greater than the unwound outer circumference of the belt forming roller (5) or of the blank, d) the belt forming roller (5) is heated internally during the manufacture of the drive belt (20) in such a way that the blank is continuously heated for stepwise forming and vulcanization, e) the forming belt loop (3) interacts on its outer side in the area of ​​rolling on the pitch circle of the belt forming roller (5) with support elements (1) which are pivotably and flexibly arranged on a carrier belt (7) that partially surrounds the belt forming roller (5) and the forming belt loop (3), and wherein the forming belt loop (3) is pressed onto the belt forming roller (5) by the carrier belt (7) with the aid of deflection and tensioning rollers (2, 6, 8) acting on the carrier belt (7) in such a way that a circumferential forming and vulcanization mold (30) whose volume changes in the rolling area is formed in the rolling area, so that over several revolutions i) initially, and with increasing heating, the tubular blank is formed between the outer negative mold (5a) of the belt forming roller (5) and the inner negative mold (3a) of the forming belt loop (3) with its profiling on both sides in such a way that the tensile cords / reinforcing elements of the blank are penetrated by the material of the applied rubber layer, ii) then, with further heat input and further rotation of the forming belt loop (3) pressed onto the carrier belt (7) and the support bodies, the blank formed into the double-sided profiled drive belt (20) is vulcanized. [2] Method according to claim 1, wherein, according to method feature e) i), the shaping of the double-sided profiling of the tubular blank takes place over several cycles when the blank is heated to a temperature of 110° C and at a rotational speed that is higher than that of the subsequent vulcanization. [3] Method according to claim 1 or 2, wherein according to method feature e) ii) the vulcanization of the formed blank over several cycles takes place when the blank is heated to a temperature of 180° C and at a rotational speed which is lower than in the preceding forming. [4] Method according to claim 3, wherein the pressure exerted on the belt forming roller (5) by means of deflecting and tensioning rollers (2, 6, 8) acting on the carrier belt (7) is maintained during the forming process and subsequently for at least the first 15% of the vulcanization phase or vulcanization cycles. [5] Device for carrying out the method according to claims 1 to 4, which has the following features: a) a drum-shaped belt forming roller (5) mounted in a machine frame so as to be rotatable on at least one side, which is provided on its outer side with a negative mold (5a) for the inner profiling of a drive belt (20), in particular with a negative mold (5a) for the inner toothing of a double toothed belt, b) a flexible forming band, a so-called forming band loop (3), surrounding the belt forming roller (5) in the form of an endless loop, which on its inner side (3a) facing the belt forming roller (5) is designed as a negative mold for the outer profiling of a drive belt (20), wherein the forming band loop (3) rolls on a partial circle (5b) of the outer circumference of the belt forming roller (5), including a drive belt blank applied to the belt forming roller (5) and forming a circumferential vulcanization mold (30) in the rolling area which changes in volume, c) wherein the forming belt loop (3) is guided and synchronized circumferentially by guide elements (4) arranged on the end faces of the belt forming roller (5) and the forming belt loop (3) has a length which is greater than the unwound outer circumference of the belt forming roller (5) or of the blank, d) a carrier belt (7) with support elements (1) provided on one side, pivotably and flexibly arranged, wherein the carrier belt (7) supports the forming belt loop (3) on its rear side facing away from the belt forming roller (5) via the partial circle (5b) over which the forming belt loop (3) rolls on the outer circumference of the belt forming roller (5), with its support elements (1). e) deflection rollers (2, 6) arranged at intervals on both sides of the drum-shaped belt forming roller (5) for the carrier belt (7) and at least one further tensioning roller (8) acting on the carrier belt (7), whereby the forming belt loop (3) is pressed onto the pitch circle (5b) of the belt forming roller (5) in the rolling area via the carrier belt (7) and the support elements (1). [6] Device according to claim 5, wherein the forming band loop (3) is designed as a flexible metallic corrugated band in profile shape. [7] Device according to claim 5, in which the forming belt loop (3) is designed as the negative form for the external profiling of the drive belt (20) to be produced, containing and vulcanized toothed belts, i.e. as a so-called counter-profile belt. [8] Method with a device according to one of claims 5 to 7, wherein the guide elements (4) are designed as toothed flanges or wheel flanges that engage in the negative shape of the forming belt loop (3).

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