V-ribbed belt and method for showing a wear state of a V-ribbed belt

Abstract

For showing a wear state of a V-ribbed belt, which is constructed with a belt backing (1), a tension strand (2) arranged underneath the belt backing and a carcass (4), in which there are formed, in the longitudinal direction of the V-ribbed belt, V-ribs (7) which run parallel to one another, have in each case an interspace (8) with respect to one another and have inclined rib flanks (12), wherein the interspaces (8), formed for the engagement of pulley ribs (11) of a V-belt pulley (10), between two V-ribs (7) of the V-ribbed belt extend as far as a rib base (9) of the V-ribs (7), according to the invention a removal of material in the rib base (9) is detected as a criterion for the wear state.

Claims

1. A V-ribbed belt with wear state indicator, comprising: a belt backing; a tension strand disposed below the belt backing; and an underside in which are configured V-ribs having oblique rib flanks which in a longitudinal direction of the V-ribbed belt run mutually parallel and which each have a mutual intermediate space configured for engagement of pulley ribs of a V-belt pulley between two V-ribs of the V-ribbed belt, wherein the intermediate space extends up to a rib base of the two V-ribs, wherein the underside is composed of at least one first material and of at least one second material, wherein the first material is covered by the second material, wherein the first material has a first color and the second material has a second color that is visually identifiable as different from the first color, wherein a thickness of the second material in a region of the rib flanks is larger than in a region of the rib base such that removal of the second material on the underside due to wear exposes the first material in the region of the rib base and makes visible the first color of the first material in the region of the rib base and the second color of the second material in the region of the rib flanks, and wherein the first material forms a layer of the underside that adjoins the tension strand, wherein the layer extends into the V-ribs and configures a rib core which is covered by the second material, wherein a thin layer of the second material covers the first material in the region of the rib base and wherein a thick layer of the second material covers the rib flanks, and wherein said thick layer of the second material is thicker than said thin layer of the second material.

2. The V-ribbed belt as claimed in claim 1, wherein the color of the first material is black or gray and the color of the second material is red.

3. The V-ribbed belt as claimed in claim 1, wherein the color of the first material is red and the color of the second material is black or gray.

4. The V-ribbed belt as claimed in claim 1 wherein a thickness of the second material in a region of the rib base is between 0.1 and 2 mm.

5. The V-ribbed belt as claimed in claim 1, wherein the color of the first material or the second material is a fluorescent color.

Description

(1) The invention is to be explained in more detail hereunder by means of exemplary embodiments which are described as potential embodiments and are not intended to have any function limiting the scope of the invention. In the drawing:

(2) FIG. 1 shows a section through a V-ribbed belt according to the invention, in a first embodiment in the new state; and

(3) FIG. 2 shows a section according to FIG. 2, for the V-ribbed belt in the worn state.

(4) In the exemplary embodiment illustrated, the V-ribbed belt has a smooth belt backing 1 which forms a smooth surface that points outward. A tension strand 2, which is formed from tension cables which are disposed beside one another, adjoins the other face of the belt backing 1. The tension strand 2 may be embedded in a suitable, preferably adhesive plastics material in the usual manner. A layer of a first material 3 of an underside 4 of the V-ribbed belt adjoins the tension strand, so as to face away from the belt backing 1. The layer of the first material 3 is applied to a constant thickness onto a blank sleeve, so that a straight barrier line 5 per se toward a second material 6 is formed. The first material 3 and the second material 6 may also be applied onto the blank sleeve (belt backing 1 and tension strand 2) as a two-ply material having the required thickness ratios. In the exemplary embodiment illustrated, the shaping of the underside has been performed by molding, on account of which the barrier line 5 is deformed somewhat in an undulated manner. V-ribs 7 having the intermediate spaces 8 lying therebetween are configured from the second material 6 during molding. The intermediate spaces 8 extend to a rib base 9. The rib base 9 in the illustrated exemplary embodiment is located entirely within the second material 6 which in the region of the rib base 9 covers the first material 3 by way of a thin layer having an indicated thickness a2.

(5) In one preferred exemplary embodiment, the first material 3 is composed of a colored, in particular red, EPDM (ethylene propylene diene rubber), while the second material may be formed from a usual black EPDM rubber.

(6) The drawing elucidates that the V-ribbed belt in use interacts with a respective V-rib pulley 10. The V-rib pulley 10 has pulley ribs 11 which protrude into the intermediate spaces 8 between two V-ribs 7 such that a lateral rib flank 12 of the V-rib 7 comes to bear in a planar manner under a lateral pretensioning on a lateral flank 13 of the adjacent pulley rib 11. The two lateral flanks 13 of one pulley rib 11 bear on the rib flanks 12 of the two adjacent V-ribs 7 such that a tip 14 of the pulley rib 11 terminates at a spacing from the rib base 9. The spacing that exists in the new state of the V-ribbed belt between the tip 14 and the rib base 9 is indicated in FIG. 1 as the dimension a3.

(7) The dimension a1, which is likewise indicated, elucidates the thickness of the first material 3 between the tension strand 2 and the barrier line 5 in the region of the respective rib base 9.

(8) It can be seen from FIG. 1, which elucidates the new state of the V-ribbed belt, that only the second material which is colored black, for example, can be seen from the V-ribbed belt in a plan view as viewed from the side of the V-ribs 7.

(9) FIG. 2 elucidates a wear state which can be seen on the

(10) V-ribbed belt according to the invention. By way of a removal of material on the rib flanks 12, and of automatic or manual re-tensioning of the V-ribbed belt about the V-rib pulley 10, the pulley ribs 11 now engage more deeply into the intermediate space 8 between two V-ribs 7. In the worn state illustrated in FIG. 2, the tip 14 of the pulley ribs 11 contacts the rib base 9, having removed material from the latter. The removal of material has progressed such that none of the second material 6 is present in the region of the rib base 9 anymore, so that first material 5 which is colored red, for example, is exposed in the region of the rib base 9. In a plan view of the V-ribbed belt in a region that has left behind the wrapping of the V-rib pulley 10, the black material now remains visible in the region of the V-ribs 7, while the first material, for example in a red color, becomes visible in the rib base 9. The V-ribbed belt in this view thus has a black surface, having thin red stripes in each case in the rib base 9. This view signals that the V-ribbed belt has reached a wear state in which the former is to be replaced immediately or soon, because the rib flanks 12 of the V-ribs 7 do not bear on the lateral flanks 13 of the pulley ribs 11 with the required contact pressure and optionally with the required contact area for the purpose of the transmission or zone.

(11) It can be seen that it is immaterial for the functioning of the V-ribbed belt according to the invention, whether the first material 3 extends into the V-ribs 7 or, as is illustrated in an exemplary manner in the drawing, the V-ribs 7 are formed entirely from the second material. For the capability of identifying the removal of material in the rib base 9 it is only advantageous for the rib flanks 12 to be furthermore formed from the second material 6, that is to say appear black, for example, while the wear signal appears as a red stripe on the rib base 9, for example.

(12) Accordingly, sizeable deviations in the proportions of the first material 3 and of the second material 6 in the underside 4 of the V-ribbed belt are possible. In the case of deformation in a molding method, the first material 3 may account for 5 to 95%, and the second material 6 thus for 95 to 5% of the material of the underside 4. In the case of manufacturing by a grinding method it is expedient for the proportion of the first material 3 to be 5 to 50%, and the proportion of the second material 6 to be 50 to 95% of the material of the underside 4.

(13) While a color-based identification on the rib base has been referred to in the exemplary embodiment described, the method according to the invention is not limited thereto. The principle of the method according to the invention is based on using a removal of material on the rib base 9, and not on the rib flanks 12, as a signal for a wear state. It is self-evident that removal of material on the rib base 9 may also be established by way of usual material testing apparatuses, in particular furthermore when two different materials 3 and 6 are used, and only a thin layer of the second material 6 is used on the rib base 9. If and when the two materials display different behaviors, for example in response to ultrasonic rays or X-rays, the removal of material of the second material 6 may be readily detected in this manner.

(14) The removal of material on the rib base 9 may furthermore be established also by way of distance measurement, for example by radar technology, using a simple radar sensor, wherein this sensor may be fixedly fitted in a plant. In this case, the spacing of the rib base 9 from the fixedly installed sensor may be monitored. Should the spacing by virtue of the removal of material be enlarged by a certain value, this signal may be utilized as an indicator for a wear state.

(15) However, the embodiment described eliciting a visual and in particular color-based marking of the V-ribbed belt in the base of the groove does have the advantage that no monitoring sensor system is required, as the wear state is visually identifiable.