METHOD FOR MOUNTING A MOTOR VEHICLE TYRE ON A RIM OF A WHEEL

Abstract

A method, device, and installation for mounting a motor vehicle tire on a rim of a wheel, characterized in that at least one tire bead of the motor vehicle tire is prestretched in a targeted manner before the tire is pulled onto the rim, in particular before the tire beads are pulled over the rim flanges of the rim.

Claims

1. A method for mounting a motor vehicle tire (14) on a rim of a wheel, comprising prestretching at least one tire bead (16) of the motor vehicle tire (14) in a targeted manner before the tire (14) is pulled onto the rim, in particular before the at least one tire bead (16) is pulled over the rim flanges of the rim.

2. The method as claimed in claim 1, wherein stretching forces which are introduced into the at least one tire bead (16) for prestretching the at least one tire bead are measured during the stretching process.

3. The method as claimed in claim 2, wherein the at least one tire bead has a bead diameter, and further comprising measuring the bead diameter of the at least one tire bead (16) during the stretching process.

4. The method as claimed in claim 3, further comprising comparing the measured values with stored desired or limit values.

5. The method as claimed in claim 3, further comprising storing the measured values in an, in particular electronic, data memory.

6. The method as claimed in claim 1, wherein the at least one tire bead (16) is prestretched in that the at least one tire bead (16) is stretched from a starting diameter to a target diameter and held for a predetermined holding time, in particular at least 300 ms, preferably at least 500 ms, at this target diameter.

7. The method as claimed in claim 6, further comprising, after expiry of the holding time, bringing the at least one tire bead (16) back again to the starting diameter, in particular by the stretching forces being reduced continuously, stepwise or abruptly.

8. The method as claimed in claim 1, wherein the at least one tire bead (16) is prestretched in that tensioning means (12), in particular tensioning jaws, which bear in a distributed manner over a circle circumference on the inside of the tire bead (16), are preferably uniformly radially further outwardly displaced and in so doing stretch the tire bead (16) by introducing stretching forces.

9. The method as claimed in claim 8, further comprising moving the tensioning means (12), in each case after reaching a radial end position with maximum widening of the at least one tire bead (16), back into respective starting positions with no or relatively small widening of the tire bead (16), in particular into starting positions in which no or correspondingly relatively small stretching forces are introduced into the tire bead (16).

10. The method as claimed in claim 8, wherein the tensioning means (12) are moved radially further outward at an advancing speed chosen such that a widening speed is set which lies between 20 mm/min and 800 mm/min, preferably between 100 mm/min and 400 mm/min.

11. The method as claimed in claim 8, wherein the at least one tire bead (16) of the tire (14) is at first automatically prestretched by the tensioning means (12), and in that, after prestretching the at least one tire bead (16), the tire is pulled automatically onto the rim.

12. The method as claimed in claim 11, wherein the tensioning means (12) are part of a prestretching station for prestretching the at least one tire bead (16) of a tire-mounting installation, wherein the tire-mounting installation has, downstream of the prestretching station, a pulling-on station for automatically pulling the tire (14) onto the rim.

13. The method as claimed in claim 12, wherein, after its at least one tire bead (16) has been stretched, the respective tire (14) is fed automatically to a pulling-on device, in particular of the pulling-on station of the tire-mounting installation in claim 12 in which the tire is pulled onto the rim.

14. A device for mounting a motor vehicle tire (14) on a rim of a wheel, the device comprising, in particular motor-movable, tensioning means for the targeted prestretching of at least one tire bead (16) of a motor vehicle tire (14) before the tire (14) is pulled onto a rim of a wheel, in particular before the tire beads (16) are pulled over the rim flanges of the rim.

15. A tire-mounting installation having a pulling-on station for the, in particular automatic, pulling of a motor vehicle tire onto a rim of a wheel, wherein the tire-mounting installation preferably has motor-movable tensioning means for the targeted prestretching of at least one tire bead (16) before pulling the motor vehicle tire onto the rim.

16. The tire-mounting installation as claimed in claim 15, wherein the tensioning means (12) for prestretching the at least one tire bead (16) are part of a prestretching device for prestretching tire beads (16) that is arranged upstream of the pulling-on station in the process sequence, the prestretching device comprising, in particular motor-movable, tensioning means for the targeted prestretching of at least one tire bead (16) of a motor vehicle tire (14) before the tire (14) is pulled onto a rim of a wheel, in particular before the tire beads (16) are pulled over the rim flanges of the rim.

17. The tire-mounting installation as claimed in claim 16, for mounting a motor vehicle tire (14) on a rim of a wheel, comprising prestretching at least one tire bead (16) of the motor vehicle tire (14) in a targeted manner before the tire (14) is pulled onto the rim, in particular before the at least one tire bead (16) is pulled over the rim flanges of the rim.

Description

[0022] Further features of the invention will emerge from the appended patent claims, the following description of a preferred exemplary embodiment of the invention and from the appended drawing, in which:

[0023] FIG. 1 shows an embodiment of a device according to the invention for prestretching tire beads (in cross section) with a tire which can be prestretched thereby.

[0024] FIG. 1 schematically shows a device 10 by means of which tire beads of motor vehicle tires can be prestretched in the manner according to the invention before they are pulled onto a suitable rim in a manner known per se.

[0025] For this purpose, the device 10 has tensioning means 12 designed as tensioning jaws which are arranged in a distributed manner over a circle circumference and which can in each case be moved by means of a motor drive (not shown) from a radially further inwardly arranged starting position in a radially further outward direction so as in so doing to prestretch a tire 14, or to be more precise the two tire beads 16 of the tire 14, bearing against the radial outer sides of the tensioning means 12.

[0026] In a manner which has not been illustrated, a central cone of the device 10, which bears against complementary inclined inner surfaces of the tensioning means 12, moves in a vertical direction anddepending on whether it is displaced upward or downwardthereby moves the tensioning jaws or tensioning means 12 bearing against it in each case horizontally radially further inward or radially further outward.

[0027] In a starting position of the tensioning means 12, tensioning means 12 arranged oppositely along the circle circumference are arranged at a distance from one another such that the tire 14 can be placed conveniently from above over the tensioning means 12. In this starting position, no or at best small stretching forces are transmitted to the tire beads 16, with the result that the tire 14 or the tire beads 16 is/are correspondingly unstretched or only slightly stretched. The tire bead diameter d shown in FIG. 1 corresponds in the normal state, that is to say in the unstretched state, approximately to the rim diameter in the bead seat of a rim suitable for the tire 14 or of a suitable rim of a wheel composed of such a rim and a corresponding disk.

[0028] Lower stop surfaces 18 of the device 10 ensure that the tire 14 remains in its position shown in FIG. 1 and cannot slip further downward.

[0029] In order to prestretch the tire beads 16, the tensioning means 12 are in each case moved radially outward (arrow directions) from their respective starting position. Here, they guide the tire beads 16 radially outward with them and in this manner introduce stretching forces into the tire beads 16.

[0030] The bead diameter d correspondingly increases here.

[0031] There is provision that the tire beads 16 are stretched in a controlled and uniform manner in the course of the prestretching until the tensioning means 12 each adopt a certain end position.

[0032] In this end position of the respective tensioning means 12, the tire 14 or the tire beads 16 is/are held for a certain holding time t, for example 300 ms or more, in order to optimize the stretching operation with a view to subsequently pulling the tire 14 onto the suitable rim.

[0033] The tensioning means 12 are then moved back again uniformly from the corresponding end position into their respective starting position. On account of the elasticity of the tires 14, the tire beads 16 draw together again independently until they are situated again in their starting state. In this state, the tires 14 can be lifted again from the device 10. This is because the starting positions of the tensioning means 12 are chosen such that, in these positions, in each case no or at best only a slight stretching of the tire beads 16 occurs and thus the tire is seated on the machine 10 or bears against the tensioning means 12 only with a small degree of tension or entirely without tension.

[0034] Force-measuring means 20, for example force gages, are used to determine the forces which are in each case currently introduced during widening of the tire beads 16. In addition, it is conceivable for the current values of the bead diameter d to be measured. The measurements can be carried out continuously, periodically or at certain time intervals.

[0035] For documentation, the measured values are stored in an electronic memory, with them each being assigned an identifier of the tire 14 on which measurements have been carried out, such as, for instance, a clear identification number thereof.

[0036] Furthermore, the measured values are each checked as to whether they are within permissible ranges or within permissible tolerances. For example, they can be compared with an (upper) limit value. Should, for example, the magnitude of the introduced forces or the bead diameter d reach or exceed a predetermined limit value at a certain time, this would be recognized as a fault and a signal would be generated.

[0037] As a result, the relevant tire 14 could be classified as a reject or defective tire 14 and separated out.

[0038] The device 10 preferably operates fully automatically after placing the respective tire 14. In other words, the tensioning means 12 are moved automatically outward into the end position, held there for the predetermined holding time t, and then moved fully automatically again in the opposite direction into a position in which no or only small forces of the beads 16 are exerted on the tensioning means 12, in particular into the starting position.

[0039] Moreover, the device 10 can be used as a stand-alone device, for example in workshops, so that it can carry out prestretching prior to subsequent pulling of the tires onto the rim by the respective workshop employee (if appropriate with the aid of a mounting machine or mounting tools).

[0040] However, the device 10 can also be part of an automatic tire-mounting installation, which generally also has, apart from a soaping station for soaping the beads 16, a pulling-on station for pulling the tires onto the respective rim. The process can be designed in such a way that the soaping, the prestretching, the mounting and, where appropriate, the subsequent air-filling of the tires then pulled onto the rim take place fully automatically.

[0041] Finally, there can also be provision that the device 10 has a suitable sensor system for quality monitoring of the tires. In particular, the values measured using the force-measuring means 20 can be evaluated in terms of quality criteria.

LIST OF REFERENCE SIGNS

[0042] 10 Prestretching machine [0043] 12 Tensioning means [0044] 14 Tire [0045] 16 Tire beads [0046] 18 Stop surface [0047] 20 Force-measuring means