Drive belt having a profiled belt rear side

Abstract

Drive belt having a belt rear side which is provided for driving auxiliary units, in particular V-ribbed belt, wherein the belt rear side is profiled and is preferably provided with an embossed profile, wherein the profile of the rear-side surface of the drive belt has a multiplicity of projections in the shape of truncated pyramids, the height h of which is less than 1 mm, and is preferably in macroscopic orders of magnitude where h≤0.2 mm, wherein the base areas A.sub.G of the projections in the shape of truncated pyramids have an area of ≤1.0 mm.sup.2 and the top surfaces A.sub.D have an area of ≤0.8 mm.sup.2.

Claims

1. A drive belt comprising a belt rear side which is provided for driving auxiliary units, wherein the belt rear side is profiled, wherein the profile of the rear-side surface of the drive belt has a multiplicity of truncated pyramidal projections, wherein height (h) of the truncated pyramidal projections is less than 1 mm, and wherein the truncated pyramidal projections, while taking into account usual production tolerances, have a base area (A.sub.G) of 0.8 mm×0.8 mm and a roof area (A.sub.D) of 0.6 mm×0.6 mm.

2. The drive belt as claimed in claim 1, wherein the drive belt is a V-ribbed belt.

3. The drive belt as claimed in claim 1, wherein the belt rear side is provided with an embossed profile.

4. The drive belt as claimed in claim 1, wherein the truncated pyramidal projections are configured in macroscopic magnitudes with height (h)≤0.2 mm.

5. The drive belt as claimed in claim 1, wherein the truncated pyramidal projections are configured as straight quadrilateral truncated pyramids having base areas (A.sub.G) and roof areas (A.sub.D) which are disposed so as to be substantially parallel.

6. The drive belt as claimed in claim 1, wherein the truncated pyramidal projections on the belt rear side, while taking into account usual production tolerances, have a height (h) of 0.15 mm.

7. A method for producing a drive belt having a belt rear side which is provided for driving auxiliary units, as claimed in claim 1, by a molding method in which a drive belt blank as a composite of a top ply, a tensile cord, and a substructure, and optionally a woven-fabric ply, is first produced on a belt-construction drum, thereafter is incorporated in a cylindrical vulcanizing mold which in terms of diameter is somewhat larger such that the substructure faces the internal side of the vulcanizing mold that is provided with a negative of the drive-side profile; wherein a sleeve/heating sleeve which is composed of rubber is introduced into the internal cavity of the vulcanizing mold and of the not yet vulcanized drive belt blank and while supplying compressed air and/or a heating medium is expanded such that said sleeve/heating sleeve bears internally on the drive belt blank and presses the latter into the surrounding negative of the vulcanizing mold, on account of which the external layer of the drive belt blank, specifically the substructure, or the woven-fabric ply, respectively, is pushed into the negative and is thus provided with the profile of said negative; wherein the sleeve prior thereto is produced on a metallic mandrel, the external side of said mandrel having the profile of the rear-side surface of the drive belt in the form of a multiplicity of truncated pyramidal projections; wherein the truncated pyramidal projections on the mandrel surface have a height (h) of 0.15 mm, a base area (A.sub.G) of 0.8 mm×0.8 mm, and a roof area (A.sub.D) of 0.6 mm×0.6 mm; wherein the material for producing the sleeve, in a plurality of tiers of an elastomer, is wound onto the mandrel and subsequently is vulcanized on the mandrel under external pressure, on account of which the sleeve on the internal side thereof is imparted the rear-side profile of the belt backing; and, wherein the sleeve upon completion of vulcanizing finally removed from the mandrel, then turned inside-out and in the above-mentioned manner is inserted into the internal cavity of the vulcanizing mold and of the not yet vulcanized drive belt blank.

8. The method as claimed in claim 7, wherein the mandrel for producing the profile in the form of a multiplicity of truncated pyramidal projections situated on the external side of the mandrel is first knurled and then ground.

Description

IN THE DRAWINGS

(1) FIG. 1 shows an enlarged fragment from the backing profile of a drive belt according to the invention;

(2) FIG. 2 shows an enlarged drawn illustration of a fragment of the backing profile as per FIG. 1;

(3) FIG. 3 shows a photograph of a real enlarged surface fragment of the belt rear side according to the invention; and

(4) FIG. 4 for comparison shows a diagram of the coefficients of friction CoF of conventional belt backings and belt backings according to the invention.

(5) FIG. 1 shows an enlarged fragment from the profile 1 of the belt backing of a drive belt according to the invention.

(6) When viewed together with FIG. 2, which corresponds to a manufacturing drawing of the rear face in the plan view and sectional view, it can be seen that the profile of the rear-side surface of the drive belt according to the invention has a multiplicity of truncated pyramidal projections 2 having a height h of 0.15 mm. These here are straight quadrilateral truncated pyramids having base areas A.sub.G and roof areas A.sub.D which are disposed so as to be substantially parallel.

(7) The height h of 0.15 mm can just be seen with the naked eye, so that this here relates to a macroscopic magnitude. Despite the term “macroscopic” per se being relative, of course, in many technical fields such magnitudes (small, but within the range still visible to the naked eye) are considered to be comprised by said term.

(8) The base areas A.sub.G of the respective truncated pyramidal projections here have an area of 0.8 mm×0.8 mm, thus approximately 0.64 mm.sup.2, while the roof areas A.sub.D have an area of 0.6 mm×0.6 mm, thus approximately 0.36 mm.sup.2.

(9) FIG. 3 shows a photograph which illustrates the real appearance of a fragment of the surface of the rear side of a belt according to the invention, albeit enlarged by approx. 3.5 times. Here too, the profile of the rear-side surface of the drive belt according to the invention can be identified as a multiplicity of truncated pyramidal projections.

(10) FIG. 4 shows a diagram which shows the comparison of the coefficients of friction CoF according to SAE J2432 of conventional belt backing and those with the profile according to the invention, measured directly after bringing to bear a new belt. The mean values from 20 measured belts of one type have in each case been evaluated and plotted. It can be clearly seen here that the coefficients of friction illustrated on the left side, being those of rear side of conventional belts from the prior art, are significantly below those of the belts having the profile according to the invention.

LIST OF REFERENCE SIGNS

(11) (Part of the Description)

(12) 1 Fragment of the profile of a belt backing

(13) 2 Truncated pyramidal projection

(14) A.sub.G Base area

(15) A.sub.D Roof area

(16) h Height of the truncated pyramidal projection