DE3009146C3 - Brake tester for tires, in particular bead path test stand - Google Patents

Description

The invention relates to a brake tester for tires, in particular a bead path test bench for tires with high drive torque, in which the Tires to be tested are driven by a test rim having a main shaft and by on the tread of the Brake shoes attacking the tire is braked.

In recent years tractors have been powered by engines of 100 kw and even more. The problem occurs increasingly on this Bringing engine power to the road at low speed. The traction of the tire with the The surface can be determined by appropriately shaping the tire profile and choosing the tread rubber compound and especially influenced by the axle pressure. However, the same drive torque must also are transmitted between tire and rim without impermissible sliding or bead migration occurring. Experiments to determine this slip were carried out with the most primitive means, with glued on tires reflective film strips or also chalk lines or marking colors were used.

However, this has not been proven because it is used for determination The machine had to be turned off before the bulge wandered.

The invention has set itself the task of s to measure and display bulge migration during the run. This is what makes this job solved that on the main shaft or the Prüffelgc of the brake tester a drive for an angle encoder is connected that the housing of the angle encoder via an indicator lever on to testing tire, in particular connected via a spring-loaded bolt and that the differential movement the main shaft or the test rim with respect to the housing to display the bulge path or to Shutdown of the brake tester is used. Further refinements are set out in the subclaims contain.

The invention is shown in the attached Figs. 1 and 2 are shown schematically and by way of example. It shows

F i g. 1 a schematic view,

F i g. 2 a section through the test axis of the test stand.

F i g. 1 schematically shows a brake tester for tires 7 which are mounted on a rim 2 and which be moved by a drive, not shown. An angular incremental encoder 4 is arranged in the center of the rim 2, which has an indicator lever 6 connected to the tire. On the tread of the tire attack two brake shoes 12, which by a pneumatic Device such as B. pneumatic cylinder 13 are moved in opposite directions. In this way, the Drive torque of the tire test bench opposed to a braking torque, so that at the connection point the rim with the tire a controllable moment occurs, which is achieved by sliding or by a Makes bulge migration noticeable. As soon as this slip reaches a certain value, the drive torque becomes switched off and the quality of the connection can be seen from the torque applied.

A section through the test axis along the section line II is shown in FIG. It can be seen that the main shaft I, via which the tire is driven, is hollow and that the drive shaft 3 of the angular encoder 4 is adjustable in the hollow shaft or in its extension by means of pliers 9. The housing 5 of the angular encoder 4 has an indicator lever 6 at one end, which is connected to the tire via a spring-loaded bolt 8, so that sliding between the rim 2 and the tire 7 results in a differential rotation of the drive shaft 3 with respect to the housing 5, which is displayed by the angular encoder 4 via the slip ring body 10 by providing a cable connection 15 on a stationary cover 14, from which a line leads to the display device on the dashboard 11. A digital display with preselection is installed on the control panel, which ^{enables a display in 1} Ao old or graded degrees, depending on whether the angle encoder is intended for 3600 or 4000 steps per revolution. This test stand enables two types of test.

1. Increase the braking of the tire until the preselected bead path is reached and the machine switches off automatically.

2. At a certain braking torque, possibly after several successive starts the bulge migration is determined.

Obviously, instead of the display device or also combined with it, a recorder device can be used be used. The connection of the angle encoder can also be carried out on test rim 2 without the main drive shaft becoming hollow must and it can also be the connection of the indicator lever 6 with the tire to be tested different from the described embodiment can be selected.

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Claims (5)

Patent claims: 1. Brake tester for tires, especially bead wander test stand for tires with high drive torque, in which the tire to be tested is driven via a test rim with a main shaft and is braked by brake shoes engaging the tread of the tire, thereby characterized that on the main shaft (1) or the test rim (2) of the brake tester a drive (3) for an angle encoder (4) is connected that the housing (5) of the angle encoder (4) via an indicator lever (6) with the tire to be tested (7), in particular via a sprung bolt (8) connected and that the differential movement of the main shaft (1) or the Test rim (2) in relation to the housing (5) for display of the bulge path or to shut down the brake tester. 2. Brake tester according to Claim 1, characterized in that the main shaft (1) is hollow and that the drive (3) for the angular encoder (4) is designed as a drive shaft which can be inserted into the main shaft (I) and connected to it by means of pliers (9). is braced. 3. Brake tester according to claim 2, characterized in that the drive shaft for the angle encoder (4) is designed to be removable from the main shaft (I). 4. Brake tester according to one of claims 1 -3, characterized in that the pulses of the Angle incremental encoder (4) via a slip ring body (10) to a stationary device, in particular Display device are delivered. 5. Brake tester according to one of claims 1-4, characterized in that the rotatable Housing (5) of the angle encoder (4) a stationary shell (14) is arranged, which is at its deepest Place the connection for the display device and with the rotating parts over the slip ring body communicates.