阅读说明：本技术 传动带的制造方法 (Method for manufacturing transmission belt ) 是由 安德列亚斯·朔尔岑 于 2018-07-10 设计创作，主要内容包括：本发明用于制造传动带。为此提供铸造工具(G)的型芯(1)和外模(20)。在型芯(1)插入外模(20)中时,在铸造工具(G)中形成空腔(22)。型芯(1)或外模(20)具有待形成在传动带上的几何形状(2),其具有彼此间隔的突起(3a、3b)和凹处(4)。在几何形状(2)上放置织物覆层(12),其支撑在突起的顶面(7)上。在织物覆层(12)上放置牵拉载体(14),从而织物覆层(12)固定在牵拉载体(14)与相应的顶面(7)之间。在将如此装备的型芯(1)插入到外模(20)中之后以可浇铸的弹性体基础材料(B)填充空腔(22)和间室(17)。(The invention is used for manufacturing the transmission belt. For this purpose, a core (1) and an outer die (20) of a casting tool (G) are provided. When the core (1) is inserted into the outer die (20), a cavity (22) is formed in the casting tool (G). The core (1) or the outer mold (20) has a geometry (2) to be formed on the drive belt, which has projections (3a, 3b) and recesses (4) spaced apart from one another. A textile coating (12) is placed on the geometry (2) and is supported on the top surfaces (7) of the protrusions. A pulling-on carrier (14) is placed on the textile coating (12), so that the textile coating (12) is fixed between the pulling-on carrier (14) and the respective top surface (7). After the core (1) thus equipped is inserted into the outer mold (20), the cavity (22) and the intermediate space (17) are filled with a castable elastomer base material (B).)

1. A method for manufacturing a transmission belt, comprising the following working steps:

a) providing a core (1) and an outer mold (20) of a casting tool (G), wherein the core (1) is intended to be inserted into the outer mold (20) such that a cavity (22) delineating the shape of the drive belt to be produced is formed between the outer mold (20) and the core (1) placed therein, and wherein the circumferential surface of the core (1) corresponding to the cavity (22) or the inner circumferential surface (21) of the outer mold (20) corresponding to the cavity (22) has a geometric shape (2) to be formed on the drive belt, a plurality of projections (3a, 3b) being arranged at a distance from one another and having a top surface (7) spaced from the base surface (8) of the geometric shape (2) and side surfaces (5, 6) on opposite sides of one another, and wherein mutually opposite side surfaces (5, 6) of mutually adjacent projections (3a, 3b) and respectively present on two adjacent projections (3a, 3b), 3b) The base surfaces (8) therebetween each define a recess (4) of the geometric shape (2);

b) placing a cloth cover (12) onto the geometry (2) such that, on the one hand, the cloth cover (12) is supported on the top faces (7) of the projections (3a, 3b) and, on the other hand, a section (13) of the cloth cover (12) extends past each of the recesses (4) of the geometry (2);

c) placing the pulling carrier (14) on the geometry (2) covered with the coating of fabric (12) in such a way that the pulling carrier (14) is supported on the top side (7) of the projection (3a, 3b) of the geometry (2) and that, on the one hand, the coating of fabric (12) is fixed between the pulling carrier (14) and the respective top side (7) in the region of the top side (7) of the projection (3a, 3b) and, on the other hand, a compartment (17) is defined in each recess (4) between a section (13) of the coating of fabric (12) extending through the respective recess (4) and a section (18) of the pulling carrier (14) spanning the recess (4) in question;

d) inserting the core (1) into the outer mold (20);

e) introducing a castable elastomer base material (B) into a cavity (22) existing between an outer mold (20) and a core (1) placed therein, such that the cavity (22), including a compartment (17) defined by a section (13) of the textile coating (12) and the pulling carrier (14) in the region of the recess (4), is filled with the elastomer base material (B), wherein the section (13) of the textile coating (12) corresponding to the recess (4) of the geometry (2) is pressed by the elastomer base material (B) against the side faces (5, 6) of the projections (3a, 3B) and the corresponding base face (8) of the respective recess (4);

f) optionally: subsequent pressing of the elastomeric base material (B) after complete filling of the cavity (22) and the recessed area with the base material, to cause a pressure rise within the cavity (22);

g) optionally: maintaining the pressure on the elastomeric base material (B) until the elastomeric base material (B) becomes sufficiently strong;

h) demoulding the obtained transmission belt coil;

i) optionally: the belt is separated from the coil.

2. Method according to claim 1, characterized in that the coated fabric layer (12) is drawn with its section (13) extending through the respective recess (4) into the respective recess (4) of the geometric shape (2) during the placement of the pulling carrier (4) (working step c)).

3. Method according to claim 2, characterized in that during the placing of the pulling carrier (12) onto the geometrical shape (2) an underpressure is generated in the area of the recess (4).

4. A method according to claim 3, characterized in that, for loading the recess (4) with underpressure, air is evacuated through at least one evacuation opening (9, 11) opening into one of the side faces (5, 6) or the base face (8) defining the respective recess (4).

5. Method according to any of the preceding claims, characterized in that the geometry (2) is built on a mandrel (1), to which the coating of fabric (12) is fixed by means of a pulling support (14).

6. Method according to any one of the preceding claims, characterized in that the textile covering (12) is constructed as a hose.

7. Method according to any one of the preceding claims, characterized in that the pulling carrier (14) is placed onto the covering of fabric (12) in two or more strands.

8. Method according to claim 7, characterized in that a plurality of pulling carrier strands are laid onto the coating of fabric (12) extending parallel to each other.

9. Method according to any one of the preceding claims, characterized in that the textile overlay (12) is impermeable to the elastomeric base material.

10. Method according to any one of the preceding claims, characterized in that the textile covering (12) is air-impermeable.

11. The method as claimed in claim 9 or 10, characterized in that the textile covering (12) has a textile layer and a coating carried by the textile layer, which coating achieves a corresponding impermeability of the textile covering (12).

12. The method of claim 11, wherein the coating is a film applied to the fabric layer.

Technical Field

The present invention relates to a method for manufacturing a transmission belt.

Background

One such method is known from WO 2017/153021 a 1. In this known method, the core and the outer die of the casting tool are provided in a first working step. The outer circumferential surface of the core or the inner circumferential surface of the outer die has a geometry which is to be formed on the drive belt. In a further working step, a textile coating is placed on the geometry. In a third working step, the core is placed in the outer mold so that the core and the outer mold define a cavity therebetween. Alternatively, the traction support can be arranged in the cavity and the cavity can be sealed off from the environment at least in the region of the geometry that is to be formed on the belt. After the positioning of the core in the outer mold, the textile coating is applied to the geometrically defined surfaces in a fourth working step, wherein the application of the textile coating to the geometrically formed surfaces is assisted by the generation of a negative pressure in the region of the empty spaces which are present between the textile coating and the geometric shape after the application of the textile coating. Next, an elastomeric base material is introduced into the cavity of the casting tool and held there until it hardens. Finally, the belt coil may be stripped from the casting tool and mass produced into individual belts in a conventional manner.

With the known method, simplified production of the toothed belt, in particular compared to conventional methods, is achieved in the case of the production of drive belts based on elastomers. Alternative materials can also be used here as a basis for the production of the drive belt, for example rubber materials, such as natural or synthetic rubber, silicone-based materials.

Disclosure of Invention

Starting from the prior art described above, the object is to further simplify the known method.

The invention solves this object by the method set forth in claim 1.

Advantageous embodiments of the invention are given in the dependent claims and are explained in detail below together with the overall inventive concept.

The method for manufacturing a drive belt according to the invention therefore comprises at least the following working steps:

a) providing a core and an outer mold of a casting tool, wherein the core is intended for insertion into the outer mold so that a cavity which delineates the shape of the drive belt to be produced is formed between the outer mold and the core placed therein, and wherein the circumferential surface of the core corresponding to the cavity or the inner circumferential surface of the outer mold corresponding to the cavity has a geometry to be formed on the drive belt, a plurality of projections being arranged at a distance from one another and having a top surface spaced apart from a base surface of the geometry and side surfaces on opposite sides from one another, wherein the mutually opposite side surfaces of mutually adjacent projections and the base surface respectively present between two mutually adjacent projections define a recess of the geometry;

b) placing the textile covering onto the geometric shape such that, on the one hand, it rests on the top surfaces of the projections and, on the other hand, sections of the textile covering extend past in each case one recess of the geometric shape;

c) placing the pulling carrier on the geometry covered with the coating of cloth, such that the pulling carrier rests on the top side of the protrusion of the geometry and, on the one hand, the coating of cloth is fixed in the region of the top side of the protrusion between the pulling carrier and the respective top side and, on the other hand, a chamber is defined in each recess between the section of the coating of cloth extending over the respective recess and the section of the pulling carrier spanning the recess concerned;

d) inserting the core into the outer mold;

e) introducing a castable elastomeric base material into a cavity existing between an outer mold and a core placed therein, such that the cavity, including a compartment defined by a section of the fabric coating and the pulling carrier in the region of the recess, is filled with the elastomeric base material, wherein the section of the fabric coating corresponding to the geometrically shaped recess is pressed by the elastomeric base material against a side face of the protrusion and a corresponding base face of the respective recess;

f) optionally: after the cavity and pocket areas are completely filled with the base material, the elastomeric base material is subsequently pushed (nachdrn) to promote a pressure rise within the cavity;

g) optionally: maintaining the pressure on the elastomeric base material until the elastomeric base material becomes sufficiently strong;

h) demoulding the obtained transmission belt coil;

i) optionally: a plurality of belts are separated from the coil.

The process according to the invention is based on the process known from WO 2017/153021A 1. In order to illustrate possible process variants which are important for practical purposes, in particular to illustrate the elastomeric base material considered, the variants considered for the design of the fabric coating and the pulling support, and the measures to be taken when the elastomeric base material is introduced into the casting mold, the disclosure of WO 2017/153021 a1 is hereby incorporated by reference into the disclosure of the present application.

If a measure, a working step or a feature is described in this document as "optional (ground)", it means that the measure, the working step or the feature, respectively, is not an essential component of the invention but can be selectively carried out to obtain the advantages or effects set forth in connection with the measure in connection with the optional, the working step in connection with the optional or the feature in connection with the optional.

Thus, a core having an outer die and being inserted into the outer die is used in the method according to the invention.

For this purpose, a core or an outer mold is provided, wherein at least the core has a geometry on its circumferential side or the outer mold has a geometry to be formed on the belt on its circumferential side. The geometry is composed of a plurality of projections, two of which are separated from each other by recesses, similar to the gear geometry.

If a toothed belt is to be produced by means of the method according to the invention, this geometry relates to the negative of the tooth geometry to be formed on the belt.

In contrast to the prior art described at the outset, in the method according to the invention, the coating of fabric is fixed to the geometry by means of a pulling support before the casting core is inserted into the outer mold of the casting tool. For this purpose, the pulling support is placed on the geometry and is supported there on the top side of the projection, so that the fabric coating is then tensioned between the pulling support and the top side of the projection with its section between the top side of the projection and the pulling support. In contrast, in the region of the recess of the geometric shape, an intermediate region is then produced between the pulling support and the textile covering, which is delimited on one side by the pulling support and on the other side by a more or less loose section of the textile covering which extends over the recess.

In particular, if the geometry is formed on the outer circumference of the mandrel, it is advantageous in terms of production technology to place the pulling supports in the form of pulling support strands. Such a pulling carrier can be wound around the mandrel in a simple manner. In this case, the pulling support can be placed in two or more extended strands in order to achieve a particularly high load absorption capacity. In order to optimize the load absorption capacity, it can be particularly advantageous here if two or more pulling-off carrier strands are applied to the textile coating extending parallel to one another. It is also possible to make the individual strands of the puller carriers of different materials, so that by combining puller carriers with different properties, the best performance of the drive belt produced in the manner according to the invention in use is ensured.

If the geometry is formed on the inner circumference of the outer die, the fixing of the textile coating to the geometry according to the invention can take place by means of suitable holding elements which press the traction support against the top face of the geometry protrusion and thus promote the fixing of the textile coating to the geometry according to the invention. Thus, the holding element may for example be configured as a slider, a rod, a pin or the like which is movable longitudinally or radially. The holding element can here be shaped to make line contact with the pulling support. For this purpose, retaining elements in the form of swords, rails, strips can also be used. This is particularly suitable if the geometry to be formed on the drive belt is configured on the outer circumferential surface of the core. If the teeth on the back of the toothed belt are formed during production, depending on the shape of the corresponding tool core, a support ring or a support rail can also be used as a holding element. The retaining element retains its position during the insertion of the core into the outer mold and can then be removed from the casting tool during the filling of the casting tool cavity or after the filling of the casting tool cavity with the elastomer base material. Thus, for example, the holding element can be removed from the cavity step by step or continuously after the injection of the elastomeric base material of the first part, while leaving the pulling carrier then supported by the elastomeric base material.

The method according to the invention can be used particularly advantageously in terms of production technology if the geometry is formed on a mandrel, i.e. if a textile covering is placed onto the geometry present on the mandrel and then a pulling support is placed around the mandrel in the manner according to the invention. It has proven to be particularly advantageous here if the pulling support is usually wound as a strand of a plurality of individual fibers, fiber bundles or fiber strands around a mandrel and forms a pulling support coating by the turns of the pulling support extending alongside one another in this way. This achieves that the pulling-on carrier coating is easily placed with a specific prestress around the core, so that the pressing force required for fixing the fabric coating can be easily generated and maintained between the top face of the protrusion and the pulling-on carrier coating until the fabric coating and the pulling-on carrier coating are fixed in position in the finished drive belt by the elastomer base material of the drive belt. In this case, the turns of the traction support coating are advantageously wound such that, when the elastomeric base material is subsequently introduced into the cavity of the casting tool, the elastomeric base material passes through the usually fine passages which are present between the turns or the fibers of the traction fiber strands which form the turns, so that in the drive belt produced in the manner according to the invention the traction support turns are completely covered or enveloped by the elastomeric base material.

In the variant of the invention described above, the core is therefore covered by a hose-like textile covering which is preferably pulled onto the core in hose form, so that the pulling-off carrier is then wound onto the textile covering. In this case, the pulling-on carrier coating is subjected to a defined prestress and thus fixes the textile coating to the geometry of the core. In this case, the fabric of the fabric coating is pressed firmly against the geometric shape on top of the teeth by the pretensioning force of the tension carrier.

In a later filling process, the regions of the textile covering forming the recesses are stretched more strongly than the regions of the drawn-in carrier which are fixed to the top surfaces of the geometric projections. In this way, the sections of the textile covering corresponding to the respective recesses are pressed against the surfaces delimiting the respective recesses when the elastomeric base mass is introduced into the cavity of the mold and remain in contact there until the base mass has hardened sufficiently and the shaping process is complete.

In this case, an excessive stretching of the textile covering in the region of the recesses can be avoided in that, when the textile covering is placed, the region extending past the recesses is already pulled into or recessed into the respective recesses. Accordingly, a variant of the invention provides that, when the textile covering is placed on the geometric shape, the textile covering in the region of the recesses is already pulled or pressed into the recesses between the geometric protrusions. For this purpose, in working step b) or c) of the method according to the invention, the textile coating with its sections spanning the respective recesses can be recessed in the geometrically shaped recesses in each case, so that the sections of the textile coating corresponding to these recesses are each pulled in the direction of the base surfaces which define the respective recesses. The textile coating is precisely oriented into the recess such that the textile coating rests against the surfaces delimiting the recess without folds and precisely filling the corner regions between the surfaces adjacent to one another, which is also achieved here by pressing the elastomer base material into the cavity and the recess region during the filling of the casting tool.

The pre-stretching of the fabric covering over the sections of the geometric depression and the resulting optimal contact of the respective section on the surface defining the depression can be assisted by the generation of a negative pressure in the region of the geometric depression during the placement of the traction support. For this purpose, the geometry can already be closed off in an airtight manner on its end face during the winding of the pulling support, and a vacuum can be generated inside the recess. In order to apply an underpressure to the recess, suction can be applied through at least one suction opening which opens into the side or base surface of the respective recess.

After the placement of the pulling support is completed and the underpressure is removed, the fleece of the fleece layer in the region of the recesses can relax and thus remain relatively loose between the sections of the fleece layer clamped in the region of the top surfaces of the protrusions. It is also conceivable here to reduce the negative pressure only by a specific amount after the placement of the pulling support, so that the textile covering can also retain its basic shape within the recess, which is adapted to the shape of the recess.

In particular, when the section of the textile coating corresponding to the recess is pre-stretched or deformed or pressed into the recess, a reliable filling of the compartment enclosed by the textile coating and the traction support coating in the region of the recess with the elastomer base material can be achieved in a simple manner. In this case, the elastomer base material usually passes through the traction support coating and therefore also into compartments, which are defined in the region of the geometrically shaped recesses by sections of the traction support which each span the respective recess and the fabric coating. In the case of a complete interruption of the underpressure, it can be ensured by a suitable feed line, which is introduced, for example, from the bottom into the corresponding section of the cavity, that the recess region is also reliably filled with the elastomer base material, and that the textile coating is thereby brought into contact with the flanks of the projections defining the recesses and the base surface of the corresponding recesses as a result of the filling pressure with which the elastomer base material is introduced into the cavity of the casting tool.

If the pressure exerted by the elastomer base material during the filling of the cavity of the casting tool is sufficiently high, or if the section of the textile coating corresponding to the recess is already sufficiently pre-stretched or deformed into the respective recess before or during the placement of the draw coating, the application of the negative pressure can be completely dispensed with or significantly reduced during the filling of the elastomer base material, as a result of which not only is the casting tool significantly simplified, but the energy consumption required to generate the negative pressure can be saved.

In addition to the application of an underpressure to assist the geometric contact of the textile coating, it is alternatively or additionally also possible to use mechanical aids, for example the holding elements already mentioned above for the arrangement of the pulling support on the inner circumferential surface of the outer mold, which hold the sections of the textile coating corresponding to the recesses in the recesses between the geometric projections in a pressing manner. It is also possible here to refer to slides, rods, pins, swords, rails, bars, etc., which can be moved longitudinally. It is optimally adapted to the shape and size of the recess of the projection, so that it holds the textile covering against the faces defining the respective recess as precisely as possible, but does not interfere with the pulling of the carrier covering when it is placed on the top face of the geometrically shaped projection.

After the textile covering has been fixed to the geometry in the manner according to the invention, the casting tool is completed by inserting the core into the outer mold (process step d)).

The filling of the cavity of the casting tool with the elastomer base material then takes place, wherein the region enclosed by the textile coating and the traction support in the region of the geometric recess is filled during the filling process, in particular also with the elastomer base material, and the textile coating is pressed tightly and smoothly onto the surfaces defining the geometric recess in the manner which has likewise been explained.

A particular advantage of the method according to the invention is that the fabric of the fabric coating is particularly uniformly spread. The coating thus has a uniform strength over the entire surface of the casting tool geometry and thus of the drive belt formed in the casting tool covered by the coating. The textile coating therefore has a strength which ensures a high load-bearing capacity and thus a long service life, in particular in the region of the transmission belt in which forces are transmitted.

In order to minimize the effort for pre-stretching the section of the textile coating corresponding to the geometric recess by means of underpressure and to assist the pressing of the textile coating according to the invention on the face defining the recess, it is advantageous if the textile coating is impermeable to the elastomer base material. In this way, during the filling process, until the elastomer base material hardens, a maximum pressing pressure of the base material is applied, by means of which it is ensured that the textile covering lies securely against the surface provided for it in each case. If the process is to be assisted by the application of negative pressure in the region of the depressions, it is advantageous for this purpose if the textile covering is also impermeable to air. The corresponding impermeability of the fabric coating can be achieved in that the fabric coating has a fabric layer which ensures the required mechanical load-bearing capacity of the fabric coating, and a coating carried by the fabric layer which imparts the corresponding impermeability to the fabric coating. The coating can be applied to the textile layer as a film, for example. In this case, of course, two or more textile layers or two or more coatings can also be provided in each case in order to achieve the optimum properties of the textile coating for the respective requirements.

The method according to the invention is at the same time suitable for manufacturing drive belts having a closed shape, i.e. for example circular in the non-use state, or non-closed, i.e. having a specific starting point and a specific end point.

By "textile" is understood here all flat elongated products for technical purposes, which are made of threads or fibers connected to one another. These include textiles produced by weaving methods, which are particularly suitable for the purposes according to the invention. However, knits, hook fabrics, nonwovens (geleges) and all other fabrics which, in the drive belt produced according to the invention, meet the object of the fabric coating provided there according to the invention can also be used.

The fabric constituting the fabric covering to be placed on the geometry to be formed on the belt for the manufacture of the drive belt according to the invention can be made of polyamide or an alternative material. The respective fabric can optionally contain a friction-reducing component, such as polytetrafluoroethylene threads, for example, during use.

The geometry provided in the casting tool according to the invention and to be formed on the drive belt produced is typically configured as a toothed geometry, which is common in many customary drive belts of today, which are therefore also referred to in practice as "toothed belts".

The pulling carrier may be made of glass fibers, aramid fibers, carbon fibers, polyester fibers, steel wires, steel strands or other materials of sufficient strength and flexibility suitable for use as a pulling carrier. Here, it is of course possible to combine different fibres with each other in order to achieve an optimal behaviour of the pulling support in the event of loads occurring in use. Thus, for example, it is advantageous to combine high-strength fibers with particularly flexible fibers in order to achieve the same high flexibility of the traction support at the same time as a high traction load capacity. Instead of a bundle of pulling-off carrier strands wound to form a pulling-off carrier coating, the pulling-off carrier coating can also be designed as a fabric cut. The fabric is preferably constructed such that its warp and weft yarns surround a plurality of openings that are sized to allow the elastomeric base material to pass through them. In such an open-pored fabric through which the elastomer base material passes in the finished belt, a strong bond of the traction support coating to the elastomer base material is ensured in a simple manner, thereby ensuring that forces which are applied to the belt during operation are reliably absorbed by the traction support.

For the purposes according to the invention, elastomers are used as elastomer base material, which may be polyurethane materials (thermosets or thermoplastics), rubber materials, silicone materials or other materials which are suitable for use as elastomer base materials for the production of drive belts and which can be processed by casting techniques of the type according to the invention. Mixtures or compounds of these materials may of course also be used.

The fabric forming the fabric coating or, in the case of a drawn-off carrier fabric cutting element, the fabric cutting element can comprise identification means which, when the produced toothed belt is used, identify the drive belt as a passive element and/or detect at least one property or at least one state of the belt as an active element and transmit it to a signal receiving device.

Optionally, the elastomeric base material is subsequently pushed and pressure is maintained on the elastomeric base material after filling the cavity until the elastomeric base material is stabilized. The obtained coil is demolded and optionally divided into a plurality of toothed belts.

Drawings

The invention is further elucidated below on the basis of the drawings showing embodiments. In which are respectively schematically shown:

FIG. 1 shows in perspective view a core of a casting tool for manufacturing the drive belt;

FIG. 2 shows the core according to FIG. 1 with the textile overlay applied thereon in a view corresponding to FIG. 1;

fig. 3 shows the mandrel according to fig. 2 with the pulling support resting thereon in a view corresponding to fig. 1 and 2;

FIG. 4 shows a mold tool for making the belt in cross section taken along the line X-X shown in FIG. 5;

fig. 5 shows a section of the mould tool according to fig. 4 along its longitudinal axis in a state ready for introducing an elastomeric base material;

fig. 6 shows the casting mold according to fig. 4 after filling with an elastomer base material in a view corresponding to fig. 5.

Detailed Description

The tubular core 1 shown in fig. 1 has a geometry 2 on the outer circumference, which is designed in the manner of an external toothing consisting of alternately arranged projections 3a, 3b and recesses 4, wherein a recess 4 is present between each of the two projections 3a, 3 b. The projections 3a, 3b and the recesses 4 each extend in parallel with the longitudinal axis L of the core in the longitudinal direction LR of the core 1.

The projections 3a, 3b are shaped in the form of teeth of a gear having external teeth, and have side faces 5, 6 converging toward a top face 7 of the projections 3a, 3b and forming an obtuse angle with the top face 7, respectively. With its side facing away from the top surface 7, the side surfaces 5, 6 each merge into a base surface 8 of the respective recess 4 between the two projections 3a, 3 b. In this way, each recess 4 is delimited on its longitudinal side by one of the side faces 5, 6 of the projections 3a, 3b adjacent to this recess 4 and on its bottom face by the base face 8, and the respective top face 7 is arranged spaced apart from the base face 8.

The core 1 encloses a cylindrical space, as shown in fig. 4 and 5, in which a central exhaust duct 9, oriented coaxially with the core 1, occupying the inner chamber of the core 1, is optionally provided. Starting from this central exhaust duct 9, as can also be seen in fig. 4 and 5, a plurality of exhaust openings 11, which each open into the base surface 8 of one of the recesses 4, optionally each issue in the radial direction R through the peripheral wall 10 of the core 1.

In order to produce a toothed-strip coil from which more toothed strips can be separated later on, a fabric covering 12, which is designed as a hose, is placed around the core 1. The textile coating 12 is formed here from at least one textile layer and a coating which adheres as a film to the textile layer and in this way prevents air and the elastomer base material B of the drive belt to be produced from penetrating the textile coating 12.

The circumference of the textile coating 12, taking into account its elasticity, is designed so that it is equal to the contour line length of the geometric shape 2 in the stretched state, so that the textile coating 12 can therefore rest without wrinkles on the side faces 5, 6 of the geometric shape 2 and the raised top face 7 and the base face 8.

The core 1 thus fitted with the textile coating 12 is then wound with a bundle of pulling carrier threads 14 of pulling carrier fibres. During this arrangement of the pulling support 14 on the core 1 carrying the fabric covering 12, air is drawn out of the region of the pockets 4 through the venting ducts 9 and the venting openings 11 connected thereto, so that the pockets 4 are subjected to an underpressure. The section 13 of the textile covering 12, which in each case passes freely over the recess 4, is drawn into the recess 4 by this underpressure and is stretched here, so that it is moved at least in the general direction in the direction of the side faces 5, 6 and the base face 8 delimiting the respective recess 4.

The pulling carrier strands 14 are kept under tensile stress during winding, so that the sections 15 of the fabric covering 12 which are placed on the top faces 7 of the protrusions 3a, 3b and are pressed by the strands 14 are pressed against the respective top faces 7 with a pressing force which is sufficient to fix them. The strand 14, by which the fabric coating 12 is held in position on the core 1, forms a pulling-on carrier coating 16 in this way, and the strand 14 is wound helically in its turns side by side on the core 1 carrying the fabric coating 12. In this case, in the region of the pockets 4, between the traction support layer 16 and the section 13 of the fabric coating layer 12 recessed into the respective pocket 4, there is a respective compartment 17, which is delimited by the section 13 of the fabric coating layer 12 concerned and the section 18 of the fabric coating layer 12 spanning the respective pocket 4. At the same time, there is a small spacing between the turns of the coil formed by the pulling carrier strand 14 around the fabric cover 12 (fig. 3).

The core 1 covered with the fabric coating 12 and wound with the pulling-on carrier coating 16 is inserted into the cylindrical interior of the outer mold 20. The diameter of the inner chamber of the outer die 20 is designed such that a cavity 22 is formed between the inner circumferential surface 21 of the outer die 20 and the core 1.

After the positioning of the core 1, the cavity 22 is closed by means of a cover 23. The cover 23 has an interface 24 for the central venting line 9, which is connected to a venting device, not shown here. At the same time, the cover 23 has at least one venting opening 25 by means of which the air contained in the cavity 22 can be discharged when the cavity 22 is filled with the elastomeric base material B.

The support of the core 1 on the cover 23 is performed by an end face 26 of the cover 23 corresponding to the cavity 22. The end face 26 of the cover 23 rests on the upper end face of the core 1, clamping the fabric covering 12 terminating there and preventing it from slipping.

On the side opposite the cover 23, the core 1 and the housing 20 are placed on a base 28, which seals the cavity 22 at the bottom side of the core 1. In this case, the core 1 rests with its lower end face on the base 28, so that the fabric covering 12 is also prevented from sliding on the core 1 there.

Furthermore, at least one nozzle 31 is guided through the base 28, through which nozzle 31 the elastomer base material B is introduced into the cavity 22 after the core 1 with the textile coating 12 on its geometry 2 and the pulling-off carrier coating 16 wound around the textile coating 12 have been placed into the outer mold 20. In the exemplary embodiment shown here, a plurality of nozzles 31 are introduced into the base 28 at uniform angular intervals distributed around the longitudinal axis L, so that an even filling of the cavity 22 is facilitated.

The elastomeric base material B introduced into the cavity 22 penetrates the traction carrier coating 16 and enters the compartment 17. For this purpose, the elastomer base material B is introduced through the gaps that are present between the windings of the pulling-on carrier strand 14, if appropriate within the windings, so that the pulling-on carrier coating 16 is penetrated and enveloped by the elastomer base material B.

The elastomer base material B which enters the compartments 17 in this way presses against the sections 13 of the fabric covering 12 which surround the respective compartment 17 and brings the section 13 concerned into non-crimped abutment against the side faces 5, 6 and the base face 8 which define the respective recess 4.

The pressing-in of the elastomer base material B continues until the cavity 22 and the resulting compartment 17 are completely filled with the elastomer base material B and therefore the side faces 5, 6 and the base face 8 of all the recesses 4 are completely covered by the corresponding sections 13 of the textile coating 12.

After the filling process is finished, the vent 25 is closed. Optionally, a brief pressure rise in the elastomer base material B present in the cavity 22 can now be caused. For this purpose, the elastomer base material B injected with a higher overpressure ("subsequent pressing") increases the reliability of the formation of the geometry 2 of the core 1 by means of the textile coating 12 and the elastomer base material B. Air possibly still present between the fabric and the geometry 2 can be discharged through the exhaust openings 11 and the exhaust duct 9.

Next, the casting tool G, comprising the core 1, the outer die 20, the cover 23 and the base 28 with the other functional elements and other components set forth herein, which are normally required for running such a tool, is kept closed until the elastomeric base material B has hardened to such an extent that the subsequently obtained drive belt coil can be demolded. For this purpose, the cover 23 and the base 28 are removed from the outer mold 20 and the core 1 is pulled off the coil.

From the obtained coil of drive belt, a plurality of drive belts are cut off in a known manner, the width of which corresponds to the requirements of the respective customer. These belts have on one side teeth formed thereon by the geometry 2 of the core 1, while the opposite side is smooth. The teeth are covered with a fabric coating 12, on the side of which, which is exposed and faces away from the elastomer base material B of the drive belt, neither an auxiliary film nor the elastomer base material B is present in the stripped state from the core 1.

The invention is therefore used for the manufacture of drive belts. For this purpose, a core 1 and an outer die 20 of the casting tool G are provided. When the core 1 has been inserted into the outer die 20, a cavity 22 is formed in the casting tool G. The core 1 or the outer mould 20 is provided with the geometry 2 that should be formed on the drive belt. The geometry has projections 3a, 3b which project from a base surface 8 and are arranged at a distance from one another, with a top surface 7 and a plurality of side surfaces 5, 6 which, with the base surface 8 respectively present between two adjacent projections 3a, 3b, each define a recess 4 of the geometry 2. A textile coating 12 is placed on the geometry 2, which is supported on the top side 7 and extends in each case with a section 13 in the region of the recess 4. A pulling support 14 is placed on the coated scrim layer 12, so that the coated scrim layer 12 is held between the pulling support 14 and the corresponding top surface 7. At the same time, in each recess 4, a compartment 17 is defined between the section 13 of the fabric covering 12 extending within the extent of the recess 4 and a section 18 of the pulling support 14 spanning the recess 4. After the thus equipped core 1 has been inserted into the outer mold 20, the cavity 22 and the intermediate space 17 are filled with a castable elastomer base material B. Thereby, the sections 13 of the fabric coating 12 are pressed by the elastomer base material B against the side faces 5, 6 of the protrusions 3a, 3B and the corresponding base faces 8 of the respective recesses 4. After the base material has hardened, the resulting drive belt roll can be demolded.

Description of the reference numerals

1 core of casting tool G

2 geometry of the core 1

3a, 3b protrusions of geometry 2

4 recesses of geometry 2

5. 6 side surfaces of the projections 3a, 3b

7 top surfaces of the protrusions 3a, 3b

8 base surface of recess 4

9 Central exhaust duct

10 peripheral wall of core 1

11 exhaust opening

12 Fabric overlay

13 section of the textile covering 12 spanning the recess 4

14 pull carrier strand

15 sections of the textile covering 12 on the top 7 of the protrusions 3a, 3b

16-pull carrier coating

17 are defined by the sections 13 of the cloth cover layer 12 recessed into the respective recesses 4 and the sections 18 of the pulling-on carrier cover layer 16 spanning the recesses 4

18 pulling the section of the carrier strand 14 spanning the respective recess 4

20 outer die of casting tool G

21 inner peripheral surface of outer mold 20

22 cavity of casting tool G

23 Upper cover of casting tool G

24 interface for central exhaust duct 9

25 vent opening in cover 23

26 end face of the cover 23

28 base of casting tool G

31 nozzle in the base 28

B elastomer base Material

G casting tool

Longitudinal axis of L-core 1

Longitudinal direction of the LR core 1

R radial direction