APPARATUS AND METHOD FOR MANUFACTURING AT LEAST ONE DRIVE BELT

Abstract

The invention relates to an apparatus for manufacturing at least one drive belt, comprising a tubular shaping body having a first inner cavity which extends in the longitudinal direction of the shaping body over the entire or predominant length of the shaping body and is surrounded circumferentially by a wall of the shaping body, wherein the inner side of the wall of the shaping body facing the first inner cavity has a shaping surface for abutment and shaping of the drive belt to be produced during the manufacturing process. The invention also relates to a method of manufacturing at least one such drive belt by means of such an apparatus.

Claims

1. An apparatus for manufacturing at least one drive belt, comprising: a tubular shaping body having a first inner cavity which extends in the longitudinal direction of the shaping body over the entire or predominant length of the shaping body and is surrounded circumferentially by a wall of the shaping body, wherein the inner side of the wall of the shaping body facing the first inner cavity has a shaping surface for abutment and shaping of the drive belt to be produced during the manufacturing process, wherein at least one of: i) the shaping body is divided in the longitudinal direction into at least two individual parts which form respective sectors of the shaping body, or ii) the apparatus has a)—an outer tube formed as a tubular body with a second inner cavity adapted to receive the tubular shaping body, or b)—another outer part outside the tubular shaping body, wherein the outer part forms with the shaping body two radially interengaging components of the apparatus.

2. The apparatus as claimed in claim 1, wherein the apparatus has a locking device, by means of which the sectors, at least in the state assembled to form the shaping body, are locked against movement in the axial direction.

3. The apparatus as claimed in claim 1, wherein the outer tube or outer part is configured for tempering the tubular shaping body by heat transfer.

4. The apparatus as claimed in claim 3, wherein the inner diameter of the second inner cavity and the outer diameter of the shaping body form a clearance fit at a temperature below 30° C.

5. The apparatus as claimed in claim 3, wherein the inner diameter of the second inner cavity and the outer diameter of the shaping body form an press fit at a temperature above 80° C.

6. The apparatus as claimed in claim 3, wherein the shaping body or its sectors are made of a material that has a higher coefficient of thermal expansion than the material of the outer tube or the outer part.

7. The apparatus as claimed in claim 1, wherein the apparatus has a heating device which is arranged for heating the outer tube or the outer part to a temperature sufficient for carrying out a manufacturing process of the drive belt.

8. The apparatus as claimed in claim 1, wherein the apparatus has a flexible and/or elastic pressure bellows, in particular in the form of a rubber bladder, which has a smooth or structured outer surface for receiving the raw material for manufacturing the drive belt.

9. The apparatus as claimed in claim 1, wherein the pressure bellows has an outer diameter which, at atmospheric pressure inside the pressure bellows, is smaller than the inner diameter of the first inner cavity at least by the thickness of the raw material for producing the drive belt arranged between the shaping body and the pressure bellows.

10. The apparatus as claimed in claim 1, wherein the apparatus is configured for producing at least one drive belt with a rib structure, in particular for producing at least one V-ribbed belt, wherein the shaping surface of the shaping body has a surface structuring which is formed as a negative profile of the ribs of the drive belt to be produced.

11. A method for manufacturing at least one drive belt by means of an apparatus according to claim 1, comprising the following steps: A) providing a raw coil made from a raw material of the drive belt, B) inserting the raw coil into the sectors of the shaping body that are not yet connected to each other or, in the case of a shaping body that is not subdivided into sectors, into the shaping body, C) in the case of a shaping body divided into sectors, connecting the sectors of the shaping body to each other so as to obtain a closed inner cavity in which the raw coil is arranged, D) insertion of an elastic pressure bellows into the interior of the raw coil, E) heating the shaping body to a first temperature, F) pressurizing an inner space of the pressure bellows for performing a pressing operation of the raw coil against the shaping surface of the first inner cavity, wherein step F) can be carried out before or after step E) or overlapping in time with step E), G) removing the manufactured drive belt from the shaping body, wherein in the case of a shaping body divided into sectors, the sectors of the shaping body are separated from one another.

12. The method as claimed in claim 11, wherein after step F) and before step G), further heating of the shaping body to a vulcanization temperature above the first temperature takes place and, when the vulcanization temperature is reached, a vulcanization insulation phase is carried out.

13. The method as claimed in claim 11, wherein after step C) and before step D), the shaping body is inserted into an outer tube of the apparatus, and is removed from the outer tube of the apparatus before the manufactured drive belt is removed from the shaping body in step G).

14. The method as claimed in claim 13, wherein heating of the shaping body is performed indirectly by heating the outer tube.

15. The method as claimed in claim 11, wherein the heating of the shaping body is carried out by means of induction heating, conduction heating and/or by a heated gaseous medium, in particular by means of steam heating.

16. The method as claimed in claim 11, wherein in step G), in the case of a shaping body divided into sectors, the sectors of the shaping body are moved away from each other in the radial direction during removal of the manufactured drive belt from the shaping body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The invention is explained in more detail below by means of exemplary embodiments with the use of drawings, in which

[0055] FIG. 1 shows a cross-sectional view of an apparatus for manufacturing a drive belt,

[0056] FIG. 2 shows the apparatus according to FIG. 1 in longitudinal section.

DETAILED DESCRIPTION OF THE INVENTION

[0057] The apparatus 1 shown in FIG. 1 has a multi-part shaping body 2, 3, which in this case is divided into two individual parts forming a sector 2 and a sector 3 of the shaping body 2, 3. It can be seen that the shaping body 2, 3 has a substantially hollow cylindrical shape. On the inside, the shaping body 2, 3 has a shaping surface 6 for the abutment of the drive belt 7 to be produced. Inside the drive belt 7 or, prior to the manufacturing process, inside the raw coil, there is a pressure bellows 8 which can be subjected to an increased internal pressure in order to press the raw coil or the drive belt 7 against the shaping surface 6. Here the space between the shaping surface 6 and the outside of the pressure bellows 8 can additionally be evacuated by means of an evacuation device.

[0058] In the assembled state shown, the sectors 2, 3 are locked against movement in the axial direction by means of a locking device, e.g. by means of a cover 4, i.e. they cannot move against each other in the axial direction. The shaping body 2, 3 is arranged inside an outer tube 5. The apparatus also has a heating device 9 which is arranged to transfer heating heat to the outer tube 5. The outer tube 5 transfers the heat to the shaping body 2, 3, which has a high thermal conductivity so that the heat is evenly distributed over the shaping body 2, 3.

[0059] Sectors 2, 3 are locked against movement in the axial direction in the assembled state shown by means of a locking device, e.g. by means of a cover 4, i.e. they cannot move relative to one another in the axial direction. The shaping body 2, 3 is arranged within an outer tube 5. In addition, the apparatus has a heating device 9, which is designed to provide thermal heat to the outer tube 5. The outer tube 5 transfers the heat to the shaping body 2, 3, which has a high thermal conductivity, so that the heat is distributed evenly over the shaping body 2, 3.

[0060] As FIG. 2 illustrates, the device 1 has a cover 4, 10 on each end face, by means of which the shaping body 2, 3 and the outer tube 5 are closed off in the longitudinal direction. At least one of the covers 4, 10 can serve as a locking device for fixing the sectors of the shaping body 2, 3 in the axial direction. To carry out the manufacturing process of the drive belt 7, the interior 11 of the pressure bellows 8 is pressurized to an excess pressure relative to atmospheric pressure.

[0061] The outer tube 5 may be configured as a ferromagnetic outer tube, for example one made of steel. The outer tube 5 has an outer diameter ADA, an inner diameter IDA and a height (or length) HA.

[0062] The shaping body 2, 3 forms a divided inner tube of the apparatus, e.g. with a fixed outer diameter ADI, an inner diameter IDI and a fixed height (or length) HI. The dividing plane of the shaping body 2, 3 can pass through the centerline of the pipe. Sectors 2, 3 can be made of a material with a higher coefficient of thermal expansion than the outer tube 5 and with good thermal conductivity, which also compensates for temperature differences in the mold. The material is preferably aluminum. The inner side of the tube has the negative profile of the ribs to be produced, so the mean inside diameter IDI is variably adapted to the belt length to be produced.

[0063] IDA and ADI can thus be adjusted to each other in such a way that there is a clearance fit at room temperature (e.g. 30° C.) and an press fit at the latest from 80° C. upwards. This allows the inner tube halves to be pushed into the outer tube at room temperature, and above 80° C., i.e. the lowest flow temperature of the coil blanks, the gap between the inner tube halves is closed.

[0064] HI and HA can be adjusted to each other so that they are higher than the raw coil at room temperature and HI<HA at the highest vulcanization temperature. Due to the cylindrical shape of the outer and inner tube, the inner tube partially slips on the outer tube 5 because of the higher coefficient of thermal expansion during heating and cooling.

[0065] The sectors can be connected, for example, by means of pins or feather keys and/or a stop of the sectors on the cover or base, which prevents axial displacement of the sectors relative to each other.

[0066] The pressure bellows 8 may be formed as a smooth rubber bladder with outer diameter ADH such that at atmospheric pressure within the pressure bellows 8, with ADH<raw coil inner diameter, the raw coil can be easily inserted and removed and at an industry standard inner pressure, the rubber bladder can press the raw coil into the ribbed negative of the inner tube. The bladder height HH can be dimensioned with HH>HA so that the rubber bladder seals the internal pressure via the cover and base. A seal relative to the outer tube 5, e.g. with O-rings, can advantageously be arranged close to the outer diameter so that any cooling water residues can be easily and completely extracted.

[0067] Cover and base can be designed with seals and sealing surfaces relative to the outer tube 5 and the pressure bellows 8 as well as to supply connections for internal bladder pressure and for mold evacuation. If the cover and base are stepped at the contact points, the above-mentioned lengths must be adapted accordingly.

[0068] It is also advantageous to treat or coat the outer and/or inner surface of the inner tube or parts thereof so that these parts are more resistant to wear or damage and have low adhesion to the coil and/or outer tube. The former is achieved e.g. by anodizing, the latter e.g. by applying a release agent—also common for steel molds. If the release agent is water-based, it is advantageous if the water is evaporated before contact with the coil blank, e.g. by heating, in order to avoid steam damage to the coil.

[0069] The heat input part of the temperature control device, i.e. the heating device 9, can comprise [0070] an induction heating device, e.g. a commercially available one for the joining of rolling bearings, with an induction coil having an inner diameter IDS, so that an air gap L=½.Math.(IDS−ADA) is created for easy insertion and removal of the mold, which is possibly further reinforced by a cooling jacket. The windings of this coil vary in their pitch in such a way that, during heating, the different heat requirements for the middle, cover and base areas with their different heat capacities and convection conditions (e.g. chimney effect) are served in such a way that the temperature distribution is sufficiently uniform. To this end, the induction coil advantageously extends beyond the mold height in the edge areas and the coil pitch is lower here than in the center. [0071] And/or the design of the outer tube as a double-walled pressure vessel, again traditionally for heating with steam, wherein the investment costs are kept within limits by the multiple use of the outer tube for many belt lengths. [0072] In addition, both heating variants can have variable thermal insulation of the cover and/or base and/or outer tube, which reduce the heat losses of the mold and thus the energy requirement and adapt changes in the zone heat requirement. These arise because when the temperature plateau is maintained, only the heat losses have to be compensated and, as in the case of heating, the heat capacities do not also have to be served. Different heat zone requirements also arise if inner mold halves with different wall thicknesses are used for a different belt length and thus a different heat capacity in the center zone is opposed by equal heat capacities in the edge zones.

[0073] The cooling part of the temperature control device can consist of [0074] for inductive heating [0075] a water bath in which the entire shaping body 2, 3 with the outer tube 5 is immersed. The water bath has the advantage that the induction heating can already be charged with the next mold, or [0076] a cooling jacket of inductively non-heatable material such as a glass-filled plastic. The cooling jacket is located in the air gap L between the induction coil and the outer tube. It forms a cavity relative to the outer tube, which is flooded with cooling water for cooling. Advantageously, inflow/inflows are at the bottom and outflow/outflows at the top, so that the cavity fills completely with cooling water and the initially generated water vapor can escape unhindered through the outflows. Due to the unobstructed discharge, the outer tube and cooling jacket do not need to be designed as a pressure vessel. The cooling jacket has the advantage that water droplets do not have to be extracted from the mold at great expense. [0077] for steam heating, traditionally consisting of a double-walled pressure vessel outer tube and diverters in the steam inlet and outlet that stop the flow of steam and direct cooling water into the cavity of the double-walled outer tube.

[0078] The method for producing drive belts by means of such an apparatus may proceed as follows: [0079] 1. Application of release agent to the shaping surface 6 of the shaping body 2, 3 and to the outside of the pressure bellows 8 [0080] 2. Finishing of the raw coil in inverted structure, but on a separable finishing drum (e.g. wedge composite), and removal of raw coil from the finishing drum [0081] 3. Insertion of the raw coil into the opened sectors of the shaping body 2, 3, then joining of the sectors with securing of axial displacement [0082] 4. Insertion of the forming body 2, 3 and the raw coil into the outer tube 5 up to a stop at the base [0083] 5. Insertion of the pressure bellows 8 completely inside [0084] 6. Closure of mold formed in this way with cover incl. internal pressure and mold evacuation connection [0085] 7. If necessary, insertion of the mold into the induction coil [0086] 8. Heating up to embossing temperature, evacuating the mold [0087] 9. Internal pressure buildup and embossing phase [0088] 10. Heating up to vulcanization temperature and vulcanization phase [0089] 11. Switching off vacuum, cooling to near room temperature, switching off internal pressure [0090] 12. If necessary, removal of the mold from the induction coil and extraction of the water drops [0091] 13. Removing the cover, removing the pressure bellows 8 and the forming body 2, 3 incl. coil or drive belt [0092] 14. Opening of the forming body 2, 3 and “peeling away” of the coil or drive belts from the shaping surface 6 [0093] 15. Repeat with new coil from step 2 or, if the release agent is used up, from step 1.

[0094] An alternative method with stop/attachment of the sectors of the forming body 2, 3 at the cover can proceed as follows and is particularly suitable for cooling with cooling jacket/double-walled outer tube, where if applicable, the outer tube, base and cooling device remain in the induction coil: [0095] 1. Application of release agent to the shaping surface 6 of the shaping body 2, 3 and to the outside of the pressure bellows 8 (as above) [0096] 2. Finishing of the raw coil in inverted structure, but on a separable finishing drum (e.g. wedge composite), and removal of raw coil from the finishing drum (as above) [0097] 3. Insertion of the raw coil into the opened sectors of the shaping body 2, 3 (as above) [0098] Insertion of the pressure bellows 8 completely inside, [0099] Closing the sectors of the shaping body 2, 3 and stop/fastening to the cover [0100] 4. Insertion of shaping body 2, 3/raw coil/cover into outer tube 5/base [0101] 5. Closure of the mold formed in this way incl. internal pressure and mold evacuation connection [0102] 6. Heating up to embossing temperature, evacuating the mold (as above) [0103] 7. Internal pressure buildup and embossing phase (as above) [0104] 8. Heating up to vulcanization temperature and vulcanization phase (as above) [0105] 9. Switching off vacuum, cooling to near room temperature, switching off internal pressure (as above) [0106] 10. Removing the cover/shaping body 2, 3/coil/pressure bellows 8 assembly, removing the cover and the pressure bellows 8 [0107] 11. Opening of the forming body 2, 3 and “peeling away” of the coil or drive belts from the shaping surface 6 (as above) [0108] 12. Repeat with new coil from step 2 or, if the release agent is used up, from step 1 (as above).