TOOTHED BELT

Abstract

The present invention relates to a toothed belt (1) having a belt body (10) which extends substantially in a longitudinal direction (X) and which comprises a flexible material, wherein at least one tension member (13), preferably a plurality of tension members (13), is at least substantially embedded in the flexible material of the belt body (10) in the longitudinal direction (X) and is at least substantially enclosed by the flexible material of the belt body (10), wherein the belt body (10) has a toothed side (11) with teeth (14) and tooth spaces (15) which alternate in the longitudinal direction (X). The toothed belt (1) is characterized in that a minimum thickness (a) of the flexible material of the belt body (10) in the vertical direction (Z) on the tension member (13) of at least one tooth space (15), preferably of all tooth spaces (15), corresponds at least to a minimum thickness (h) of the flexible material of the belt body (10) in the vertical direction (Z) on the tension member (13), wherein the minimum thickness (h) is calculated as follows in dependence on the thickness (d) of the tension member (13) in the vertical direction (Z) and on the material hardness (ShA) of the flexible material of the belt body (10) in Shore A:

h=3*d/ShA.

Claims

1.-12. (canceled)

13. A toothed belt comprising a belt body which extends substantially in a longitudinal direction (X) and which comprises a flexible material; wherein at least one tension member is at least partially embedded in a flexible material of the belt body in the longitudinal direction (X), and wherein the at least one tension member is at least partially enclosed by the flexible material of the belt body; wherein the belt body has a toothed side with teeth and tooth spaces which alternate in the longitudinal direction (X); wherein a minimum thickness (a) of the flexible material of the belt body in a vertical direction (Z) on the at least one tension member of at least one of the tooth spaces corresponds at least to a minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the at least one tension member; wherein the minimum thickness (h) is calculated as follows in dependence on thickness (d) of the tension member in the vertical direction (Z) and on material hardness (ShA) of the flexible material of the belt body in Shore A, where h=3*d/ShA.

14. The toothed belt as claimed in claim 13, wherein the minimum thickness (a) of the flexible material of the belt body in the vertical direction (Z) on the tension member of at least one tooth space furthermore corresponds approximately to the minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the tension member.

15. The toothed belt as claimed in claim 13, wherein the flexible material of the belt body comprises polyurethane.

16. The toothed belt as claimed in claim 15, wherein the flexible material of the belt body consists of polyurethane.

17. The toothed belt as claimed in claim 13, wherein the at least one tension member is a steel cable (13), and wherein the thickness (d) of the at least one tension member (13) is the diameter (d) of the steel cable.

18. The toothed belt as claimed in claim 13, wherein a fabric is arranged on the flexible material of the belt body on the toothed side in the vertical direction (Z).

19. The toothed belt as claimed in claim 13, wherein the minimum thickness (a) of the flexible material of the belt body in the vertical direction (Z) on the at least one tension member of all of the tooth spaces corresponds at least to a minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the at least one tension member

20. The toothed belt as claimed in claim 13, wherein at least one tension member is a plurality of tension members.

21. The toothed belt as claimed in claim 20, wherein the minimum thickness (a) of the flexible material of the belt body in the vertical direction (Z) on the plurality of tension members of all of the tooth spaces corresponds at least to a minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the plurality of tension members.

22. The toothed belt as claimed in claim 13, wherein at least one tension member is a plurality of tension members, wherein the plurality of tension members is a plurality of steel cables, and provided the plurality of steel cables are devoid of a zinc layer.

23. The toothed belt as claimed in claim 22, wherein the flexible material of the belt body consists of polyurethane.

24. A method for producing a toothed belt as claimed in claim 13, the method comprising the steps of: producing the toothed belt using at least one profiled roll as shaping core; identifying at least one exposed point of the at least one tension member on the toothed side; and, closing the identified exposed point of the at least one tension member (13) by application of the flexible material such that the minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the at least one tension member is achieved.

25. The method for producing a toothed belt as claimed in claim 24, wherein the application of the flexible material is provided as a coating layer of the flexible material.

26. The method for producing a toothed belt as claimed in claim 24, wherein the application of the flexible material is provided by adhesive bonding of a film of the flexible material.

27. The method for producing a toothed belt as claimed in claim 24, wherein the application of the flexible material is provided by welding-on of a film of the flexible material.

28. The method for producing a toothed belt as claimed in claim 24, wherein the application of the flexible material is provided in the form of a film, and wherein the film comprises a fabric on a side facing away from the belt body.

29. The method for producing a toothed belt as claimed in claim 24, wherein the flexible material is applied along with the material of the belt body.

30. A method for producing a toothed belt as claimed in claim 13, the method comprising the steps of: producing a flat belt comprising the at least one tension member and the belt body, wherein the toothed side has at least the minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the at least one tension member; and, forming the teeth of the toothed belt on the toothed side on the flat belt of the belt body.

31. The method for producing a toothed belt as claimed in claim 30, wherein the toothed side has at least the minimum thickness (h) of the flexible material of the belt body in the vertical direction (Z) on the at least one tension member.

32. The method for producing a toothed belt as claimed in claim 30 further comprising applying a fabric to the toothed side of the toothed belt.

Description

[0042] Two exemplary embodiments and further advantages of the invention are discussed below in conjunction with the following figures, in which:

[0043] FIG. 1 shows a schematic longitudinal section of a known toothed belt;

[0044] FIG. 2 shows a schematic longitudinal section of a known toothed belt with fabric on the toothed side;

[0045] FIG. 3 shows a schematic longitudinal section of a toothed belt according to the invention according to a first exemplary embodiment; and

[0046] FIG. 4 shows a schematic longitudinal section of a toothed belt according to the invention according to a second exemplary embodiment.

[0047] The description of the aforementioned figures is given in Cartesian coordinates with a longitudinal direction X, a transverse direction (not illustrated) which is oriented perpendicularly to the longitudinal direction X, and a vertical direction Z which is oriented perpendicularly both to the longitudinal direction X and to the transverse direction. The longitudinal direction X may also be referred to as depth X, the transverse direction may also be referred to as width and the vertical direction Z may also be referred to as height Z.

[0048] FIG. 1 shows a schematic longitudinal section of a known toothed belt 1. The toothed belt 1 has a belt body 10 which extends substantially in the longitudinal direction X and which is composed of polyurethane (PU) as a flexible material. In the flexible material of the belt body 10, a plurality of tension members 13 are arranged in the longitudinal direction X so as to run parallel to one another in the transverse direction. The tension members 13 are each embedded substantially in the flexible material of the belt body 10 and enclosed substantially to completely by the flexible material of the belt body 10. Steel cables 13 are used as tension members 13.

[0049] The toothed belt 1 has a drive side 11 and an outer side 12 facing away from the latter in the vertical direction Z. Teeth 14 and tooth spaces 15 which alternate in the longitudinal direction X are formed on the drive side 11, which is why the drive side 11 may also be referred to as toothed side 11.

[0050] During the production of such a known toothed belt 1 by means of profiled rolls as shaping cores or as shaping wheels for the formation of the teeth 14 and tooth spaces 15 of the toothed belt 1 on the toothed side 11 thereof, the tension members 13 are deposited on the outer diameter of the rolls such that the tension members 13 can come into direct contact with the roll. In this way, during revolution around the roll, the tension members 13 may be pushed out of the flexible material of the belt body 10 partially on the toothed side 11, such that the tension members 13 of the finished toothed belt 1 are free from the flexible material of the belt body 10 on the toothed side 11 at least in a punctiform manner. This may lead to the formation of exposed points 17 of the tension members 13, with the result that the tension members 13 may be exposed at these exposed points 17 of the toothed side 11 to environmental influences, for example humidity, which may lead to corrosion in the case of steel cables 13 as tension members 13.

[0051] FIG. 2 shows a schematic longitudinal section of a known toothed belt 1 with fabric 16 on the toothed side 11. In this case, the toothed side 11 of the toothed belt 1 is covered completely by a fabric 16, the inner side of which is in contact with the flexible material of the belt body 10. In this way, the fabric 16 also comes into direct contact with the aforementioned exposed points 17 of the toothed side 11, such that even in this case the tension members 13 may be exposed at these exposed points 17 of the toothed side 11 to environmental influences, for example humidity. Here, the fabric 16 may even further promote and accelerate the corrosion in that the fabric 16 can serve as a moisture store and thus prolong the exposure time of the moisture.

[0052] FIG. 3 shows a schematic longitudinal section of a toothed belt 1 according to the invention according to a first exemplary embodiment. According to the invention, in the tooth spaces 15 of the toothed side 11, which have the lowest material thickness of the flexible material of the belt body 10 in the vertical direction Z on the tension member 13, a minimum thickness a of the flexible material of the belt body 10 is provided, said minimum thickness corresponding at least to a minimum thickness h of the flexible material of the belt body 10 in the vertical direction Z on the tension member 13.

[0053] The minimum thickness h is calculated as follows in dependence on the thickness d of the tension member 13 in the vertical direction Z and on the material hardness ShA of the flexible material of the belt body 10 in Shore A:

h=3*d/ShA.

[0054] In other words, the tension members 13 are covered in the region of the tooth spaces 15 at least by a minimum thickness a of the flexible material of the belt body 10 in the vertical direction Z, said minimum thickness being equal to or greater than the minimum thickness h. This applies at least in the production state of the toothed belt 1 according to the invention. Here, it may be sufficient to observe the predetermined minimum thickness h of the flexible material of the belt body 10 and to not exceed it to a significant extent in order to not increase the weight of the toothed belt 1 unnecessarily and to use as little flexible material as possible.

[0055] According to the invention, account is in this way taken of the fact that the predetermined minimum thickness h of the flexible material of the belt body 10 is based, firstly, on the power class of the toothed belt 1, which usually determines the thickness d of the tension member 13 in the vertical direction Z. The higher the power class of the toothed belt 1, the thicker the tension member 13 in the vertical direction Z and the greater the predetermined minimum thickness h of the flexible material of the belt body 10 in the vertical direction Z on the tension member 13 is. The predetermined minimum thickness h of the flexible material of the belt body 10 is based, secondly, on the hardness ShA of the flexible material of the belt body 10 in Shore A. The harder the flexible material of the belt body 10, the lower the deformation of the flexible material of the belt body 10 is and the thinner the predetermined minimum thickness h of the flexible material of the belt body 10 can be.

[0056] The predetermined minimum thickness h of the flexible material of the belt body 10 can be achieved for example by covering identified exposed points 17 manually with, for example, a coating, or in an areal manner by the adhesive bonding or welding-on of films in corresponding sizes in the form of film pieces. Alternatively, the toothed side 11 of the toothed belt 1 may also be formed on a flat belt as belt body 10 that has already been produced. In this case, the predetermined minimum thickness h of the flexible material of the belt body 10 may have already been achieved by the formation of the flat belt or during the application of the teeth in that the tooth spaces are provided correspondingly with the flexible material.

[0057] In any case, the tension members 13 can be protected from external environmental influences in a more effective manner than hitherto known. This can in particular help to avoid the development of corrosion in the case of steel cables 13 as tension members 13. In this way, the longevity of the toothed belt 1 can be increased.

[0058] FIG. 4 shows a schematic longitudinal section of a toothed belt 1 according to the invention according to a second exemplary embodiment. In this case, the toothed side 11 is covered by a fabric 16 in order, for example, to reduce the coefficient of friction of the toothed side 11. On account of the predetermined minimum thickness h of the flexible material of the belt body 10, the fabric 16 does not come into direct contact with the tension members 13.

LIST OF REFERENCE DESIGNATIONS (PART OF THE DESCRIPTION)

[0059] a Minimum thickness of the flexible material of the (PU) belt body 10 in the vertical direction Z on the tension member 13 of a tooth space 16 [0060] d Thickness of the tension member 13 in the vertical direction Z; diameter of the tension member 13 [0061] h Minimum thickness of the flexible material of the (PU) belt body 10 in the vertical direction Z on the tension member 13 [0062] ShA Material hardness of the flexible material of the (PU) belt body 10 in Shore A [0063] X Longitudinal direction; depth [0064] Z Vertical direction; height [0065] Toothed belt [0066] (PU) belt body [0067] Toothed side; drive side [0068] Outer side [0069] Tension members; steel cables [0070] Teeth of the toothed side 11 [0071] Tooth spaces of the toothed side 11 [0072] Fabric [0073] Exposed point of a tension member 13 on the toothed side 11