Drum assembly for a tire test stand and device for grinding the outer circumferential surface of the drum

Abstract

The invention relates to a drum assembly for a tire test stand with a drum 20 rotatably driven about a drum axis 4 from the output shaft 2 or a drum shaft 3 of a rotary drive. A fixed bearing journal 6, enclosing the output shaft 2 or the drum shaft 3, is arranged coaxially to the drum axis 4. A hub 10 is rotatably mounted on the bearing journal by means of at least one hydrostatic bearing 11. The hub 10 is non-rotatably connected to the output shaft 2 or the drum shaft 3 and has a receptacle for coaxially mounting the drum 20 enclosing the hub 10.

Description

[0001] The invention relates to a drum assembly for a tire test stand with a drum rotatably driven about a drum axis from the output shaft or a drum shaft of a rotary drive.

[0002] Furthermore, the invention relates to a device for grinding the outer circumferential surface of the running drum.

[0003] In such a running drum arrangement for a tire test stand, it is known to arrange the running drum on a running drum shaft which can be connected to the output shaft of the rotary drive via a coupling, wherein the running drum shaft is rotatably mounted in bearings on both sides of the running drum.

[0004] From DE 100 19 565 A1, a device for measuring the uniformity of a vehicle tire is known, in which a roller drives a vehicle tire which is mounted in a machine frame via a piezoelectric measuring hub. The roller is mounted on a movable carriage via radial bearings and is supported axially exclusively by load cells.

[0005] DE 10 2017 120 333 A1 discloses a workpiece spindle for a grinding machine comprising a spindle for rotating a workpiece, a holding device for holding the workpiece, and a lifting device coupled to the spindle and the holding device for varying the axial distance of the holding device to the spindle. The holding device, which can be axially displaced by means of the lifting device, enables more cost-effective automated feeding of the workpiece and increased accuracy in workpiece manufacturing, thus allowing for cost-effective grinding of ring-shaped workpieces with high accuracy.

[0006] If a road surface is permanently attached to the drum and measurements are to be taken on different road surfaces, the entire drum must be replaced. To avoid having to remove the bearings, the bearings and bearing housings remain on the drum. Electrical connections of the sensors on the bearing housings must be disconnected and reconnected during the drum replacement. The alignment of the drums to the measuring hub may need to be checked and corrected. The coupling between the output shaft of the rotary drive and the drum shaft must be removed. This may require axially shifting the rotary drive. This increases the time required and therefore the cost of replacing the drum.

[0007] The object of the invention is therefore to create a running drum arrangement for a tire test stand of the type mentioned at the outset, as well as a device for grinding the outer circumferential surface of the running drum, which eliminates these disadvantages and which, with a simple design, enables cost-effective running drum replacement with backlash-free centering of the running drum to the running drum axis.

[0008] This problem is solved according to the invention by arranging a stationary bearing journal coaxially to the drum axis, enclosing the output shaft or the drum shaft, on which a hub is rotatably mounted by means of at least one hydrostatic bearing, which is non-rotatably connected to the output shaft or the drum shaft and which has a receptacle for coaxial fastening of the drum enclosing the hub.

[0009] This design according to the invention eliminates the need for bearings and bearing housings for the drum shaft and separate sensors for each drum.

[0010] Changing the running drum without manually aligning the running drum is quick and easy.

[0011] The hydrostatic bearing with a relatively large diameter allows for high radial forces.

[0012] Angular compensation of the drum bearing is not required, as the two bearing components are each housed in a separate part (bearing journal and hub). The bearing journal is sufficiently rigid, so no deflection needs to be taken into account.

[0013] For simple, backlash-free and quick-mounting centering of the running drum, the hub according to the invention has a radially outwardly projecting hub ring with which a radially inwardly projecting roller ring of the running drum can be connected coaxially to the running drum axis.

[0014] The hub ring and roller ring can be arranged parallel to each other and connected by means of an interlocking form connection, through which the roller ring can be aligned coaxially to the running drum axis.

[0015] According to the invention, the hub ring has a coaxial, radially outwardly directed, radially circumferential first conical ring surface, and the roller ring or a separate component has a corresponding coaxial, radially inwardly directed, radially circumferential second conical ring surface, wherein the second conical ring surface surrounds the first conical ring surface, and the hub ring and roller ring can be axially connected to each other in a centered manner. Thus, centering of the drum is automatically achieved during assembly.

[0016] In a simple way, the hub ring and roller ring can be axially connected to each other in a centered manner by means of a screw connection.

[0017] A backlash-free centering of the running drum can be achieved by having the first conical ring surface and / or the second conical ring surface have an excess.

[0018] Before the bolted joint is tightened, an axial gap remains in the joint's interface due to the excess material on the first and / or second conical ring surface. When the bolted joint is tightened, the preload force of the bolts closes this axial gap as the cones expand elastically.

[0019] The second conical surface of the roller ring is difficult to access with a machining tool. To make this second conical surface easier to manufacture (i.e., grind), a centering ring with the second conical surface, which can be manufactured separately, can be arranged coaxially between the hub ring and the roller ring.

[0020] To transmit the rotary motion of the output shaft to the hub, the output shaft or the drum shaft can be connected to the hub via a coaxial transmission piece.

[0021] If a coupling is arranged between the output shaft or drum shaft and the transmission piece, this results in easy assembly and disassembly of the drum.

[0022] A device for grinding the outer circumferential surface of the running drum assembly of the type described above can have a rotatably driven shaft and a radially outwardly projecting hub ring with which a radially inwardly projecting roller ring of the running drum can be connected coaxially to the running drum axis.

[0023] Grinding the outer circumferential surface of the running drum is therefore quick and easy to perform without manually aligning the running drum.

[0024] For simple, backlash-free and quick-mounting centering of the drum, the shaft can have a radially outwardly projecting hub ring with which a radially inwardly projecting roller ring of the drum can be connected coaxially to the drum axis.

[0025] The hub ring and roller ring can be arranged parallel to each other and connected by means of an interlocking form connection, through which the roller ring can be aligned coaxially to the shaft axis.

[0026] According to the invention, the hub ring has a coaxial, radially outwardly directed, radially circumferential first conical ring surface, and the roller ring or a separate component has a corresponding coaxial, radially inwardly directed, radially circumferential second conical ring surface, wherein the second conical ring surface surrounds the first conical ring surface, and the hub ring and roller ring can be axially connected to each other in a centered manner. Thus, centering of the drum is automatically achieved during assembly.

[0027] In a simple way, the hub ring and roller ring can be axially connected to each other in a centered manner by means of a screw connection.

[0028] A backlash-free centering of the running drum can be achieved by having the first conical ring surface and / or the second conical ring surface have an excess.

[0029] Before the bolted joint is tightened, an axial gap remains in the joint's interface due to the excess material on the first and / or second conical ring surface. When the bolted joint is tightened, the preload force of the bolts closes this axial gap as the cones expand elastically.

[0030] The second conical surface of the roller ring is difficult to access with a machining tool. To make this second conical surface easier to manufacture (i.e., grind), a centering ring with the second conical surface, which can be manufactured separately, can be arranged coaxially between the hub ring and the roller ring.

[0031] An embodiment of the invention is shown in the drawing and is described in more detail below. The drawing shows: Fig. 1. A side view in longitudinal section of a tire test stand with a running drum Fig. 2 a section of the tire test stand with a running drum after Fig. 1 Fig. 3 a section of a device for grinding the outer circumferential surface of a running drum.

[0032] The tire testing stand of the Fig. 1 and Fig. 2 has in a test stand housing 5 an electric motor 1 as a rotary drive, the output shaft 2 of which drives a coaxial drum shaft 3 rotatably about a drum axis 4 via a first coupling 8.

[0033] A tubular bearing journal 6, coaxial to the drum axis 4, is fixedly arranged on the test stand housing 5, through which the drum shaft 3 is guided and at its end protruding from the bearing journal 6 can be coupled to a coaxial transmission piece 9 via a second coupling 7.

[0034] The transmission element 9 is in turn non-rotatably connected to a hub 10, which is rotatably mounted on the bearing journal 6 by hydrostatic bearings 11 via two axially spaced lubricant reservoirs 13. Lubricant is continuously supplied to the hydrostatic bearings 11 via a pressure line 12 from a pump (not shown).

[0035] The transmission element 9 is rotatably mounted on a bearing sleeve 15, which surrounds the drum shaft 3 at a radial distance, above a pair of rolling bearings 14. The bearing sleeve 15 is supported on the side facing the electric motor by a support sleeve 16, which surrounds the drum shaft at a radial distance, against a stop 17 fixedly arranged on the drum shaft 3.

[0036] The hub 10 has in its central area a flange-like hub ring 18 projecting radially outwards, parallel to which a flange-like roller ring 19 of a running drum 20 enclosing the hub 10 is directed radially inwards.

[0037] The hub ring 18 and roller ring 19 are clamped against each other by axial screws 21.

[0038] The hub ring 18 has an outwardly facing, radially circumferential first conical ring surface 22, onto which a coaxially opposite, radially inwardly facing, radially circumferential second conical ring surface 24 of a centering ring 23 is partially pushed. The conical ring connection between the first conical ring surface 22 and the second conical ring surface 24 has an interference fit. The screws 21, via the roller ring 19, press the centering ring 23 with its second conical ring surface 24 axially onto the first conical ring surface 22 with preload, thereby centering the running drum 20 coaxially with the running drum axis 4.

[0039] To mount the running drum 20, it simply needs to be slid axially onto the hub 10 and connected to the hub ring 18 via the centering ring 23 and its roller ring 19 using the screws 21. The running drum 20 can be disassembled in the reverse manner, without the need to remove any further components.

[0040] In Fig. Figure 3 shows a section of a device for grinding the outer circumferential surface of a running drum 20. A rotatably driven shaft 25 has, according to the Fig. 1 and Fig. 2 a radially outward projecting hub ring 18', with which the radially inward projecting roller ring 19 of the running drum 20 can be connected.

[0041] According to the Fig. 1 and Fig. 2 the hub ring 18' is provided with a first conical ring surface 22' which can be clamped to the second conical ring surface 24 of the running drum 20 via the centering ring 23 and thus centered. Reference sign 1 electric motor 2 Output shaft 3. Running drum shaft 4. Running drum axle 5 test bench housings 6 bearing journals 7 second clutch 8 first clutch 9 Transfer piece 10 hub 11 hydrostatic bearings 12 Pressure line 13 lubricant pockets 14 rolling bearings 15 Bearing sleeve 16 Support sleeve 17 attacks 18 hub ring 18' hub ring 19 roller ring 20 running drum 21 screws 22 first cone surface 22' first cone face 23 Centering ring 24 second cone surface 25 wave

Claims

[1] Drum assembly for a tire test stand with a drum assembly (20) rotatably driven about a drum assembly axis (4) by an output shaft (2) or a drum assembly shaft (3) of a rotary drive rotatably driven by the output shaft (2), wherein a stationary bearing journal (6) enclosing the output shaft (2) or the drum assembly shaft (3) is arranged coaxially to the drum assembly axis (4), on which a hub (10) is rotatably mounted by means of at least one hydrostatic bearing (11), the hub being non-rotatably connected to the output shaft (2) or the drum assembly shaft (3) and having a receptacle for coaxial attachment of the drum assembly (20) enclosing the hub (10), and wherein the hub (10) has a radially outwardly projecting hub ring (18) with which a radially inwardly projecting roller ring (19) of the drum assembly (20) can be connected coaxially to the drum assembly axis (4), characterized by, that the hub ring (18) has a coaxial radially outward directed, radially circumferential first conical ring surface (22) and the roller ring (19) or a separate component has a coaxial radially inward directed, radially circumferential corresponding second conical ring surface (24), wherein the second conical ring surface (24) surrounds the first conical ring surface (22) and the hub ring (18) and roller ring (19) are axially connectable in a centered manner. [2] Drum assembly according to claim 1, characterized by , that hub ring (18) and roller ring (19) are arranged parallel to each other and can be connected by means of an interlocking form connection, by which the roller ring (19) can be aligned coaxially to the running drum axis (4). [3] Drum assembly according to claim 1, characterized by , that hub ring (18) and roller ring (19) can be axially connected to each other in a centered manner by a screw connection (21). [4] Drum assembly according to claim 1, characterized by, that the first conical ring surface (22) and / or the second conical ring surface (24) have an excess. [5] Drum assembly according to one of claims 1, 3 or 4, characterized by , that a centering ring (23) is arranged coaxially between the hub ring (18) and the roller ring (19), which has the second conical ring surface (24). [6] Drum assembly according to one of the preceding claims, characterized by , that the output shaft (2) or the running drum shaft (3) is connected to the hub (10) via a coaxial transmission piece (9). [7] Drum assembly according to claim 6, characterized by , that a coupling (7) is arranged between the output shaft (2) or the drum shaft (3) and the transmission piece (9). [8] Device for grinding the outer circumferential surface of the running drum (20) of a running drum assembly according to one of the preceding claims, characterized by, that a rotatably driven shaft (25) has a radially outwardly projecting hub ring (18') with which the radially inwardly projecting roller ring (19) of the running drum (20) can be connected coaxially to the running drum axis (4).

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