GB2089259A

GB2089259A - Drive transmission for driving a spindleless rolling stand

Info

Publication number: GB2089259A
Application number: GB8123834A
Authority: GB
Original assignee: Schwermaschinenbau Kombinat Ernst Thalmann VEB
Current assignee: Schwermaschinenbau Kombinat Ernst Thalmann VEB
Priority date: 1980-12-11
Filing date: 1981-08-04
Publication date: 1982-06-23
Also published as: SE446510B; DE3129811A1; DD158312A3; GB2089259B; CS237772B1; SE8106126L

Abstract

A drive transmission for driving a spindleless rolling stand with a large adjusting range for the roller shafts 11, 12, and having roller shafts 11, 12 mounted in eccentric adjusting sleeves 15, 16, includes drive wheels 17, 18 on the shafts and driven by wheels 9, 10 with internal teeth. The meshing internal and external teeth accommodate adjustment of the shafts. The axes of the internally toothed wheels 9, 10 of the gear shafts 6, 8 are located eccentrically of the axes of the eccentric adjusting sleeves 15, 16 in the housing of the gearing case 3, the pitch circles of the drive wheels 17, 18 of the rollershafts 11, 12 being at a tangent to the pitch circles of the internally toothed wheels 9, 10 of the gear shafts 6, 8 over the entire adjusting range, and that the shifting of the axes is dependent on the roller displacements in the region of the teeth, resulting from the loads and clearances necessitated by the operation. <IMAGE>

Description

SPECIFICATION Drive transmission for driving a spindleless rolling stand The invention relates to a drive transmission for driving a spindleless rolling stand with adjustment means for effecting adjustment of the roller shafts.

In DE-AS 1 427 974 the roller shafts are mounted for adjustment purposes in eccentric bushes which can be turned about their own axis. The gear wheels fixed on the roller shafts are driven by laterally arranged pivots. Exact engagement between the teeth on the drive wheel and pinion is ensured only in the central position of the eccentric bushing.

When the rollers are adjusted to bring them out of this central position, either an increase or a decrease in the centre spacing of the drive wheel arranged on the roller shafts, with the associated wheels of the pinion stage. The drawback is that this change in the centre spacing of the teeth limits the possible adjustment range of the roller shafts and makes it impossible for the valuable roller material to be utilised economically.

In DE-OS 2 103734 the principle of mounting the roller shafts in eccentric sleeves has indeed been maintained. However, the roller shafts are driven via internally toothed gear wheels. Since the eccentricity of the axis of the roller shafts relative to the axis of the adjusting sleeves, is identical with the centre spacing between the internal and external teeth, and since the axes of the rim shafts coincide with the axes of the adjusting sleeves, these teeth remain exactly in engagement when the roller shafts are adjusted. This modification thereby makes it possible to have theoretically large adjusting distances with exact engagement between teeth. However, the internal teeth have been found to be very prone to trouble when the shafts are displaced from the theoretical axis.These displacements of the shafts being the sum of the bearing clearances in the shaft bearings, (and) of the inclined positions of the shafts when loaded within range of the bearing clearances and the normal flexing of the loaded components are already large enough for sudden loads to cause trouble in engagement with the internal teeth, leading to considerable damage to the teeth. The negative effects of shifting the shafts also vary along the adjustment path, because the direction of the tooth forces varies along the adjustment path.

According to the present invention there is provided a drive transmission for driving a spindleless rolling stand with adjustment means for effecting adjustment of the roller shafts, in which said roller shafts are provided with externally toothed drive wheels and mounted in eccentric adjusting sleeves in a roller case, the drive wheels thereof engaging with internally toothed wheels of gear shafts provided in a gearing case, said roller case and gearing case being arranged in a common housing, the axes of the internally toothed wheels of the gear shafts being located eccentrically of the axes of the eccentric adjusting sleeves in a housing of the gearing case, the pitch circles of the drive wheels of the roller shafts being at a tangent to the pitch circles of the internally tooth wheels of the gear shafts over the entire adjusting range, and the shifting of the axes being dependent on the roller displacement in the region of the teeth, resulting from the loads and clearances, necessitated by the operation.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings; in which: Figure 1 is a longitudinal section through a rolling stand with a spindleless drive and internal and external teeth, Figure 2 is a section taken along the line A-A indicated in Figure 1, Figure 3 is a section taken along the line B-B indicated in Figure 1, and Figure 4 is a tooth correcting diagram.

In Figure 1 the spindleless rolling stand comprises a base housing 1, accommodating a roller case 2 and a gearing case 3. A centering system keeps the roller case 2 and gearing case 3 in their exact relative positions within the base housing 1. From a drive shaft 4 the drive torque passes via a bevel gear stage 5 to a lower gear shaft 6, which drives an upper gear shaft 8 via pinion gears 7. The two gear shafts 6 and 8 carry internally toothed wheels 9 and 10 respectively, which are in engagement with externally toothed driving wheels 17 and 18 respectively which are provided on roller shafts 11 and 12. The roller shafts 11 and 12 are respectively mounted radially in journal bearing bushings 13 and 14 which are arranged eccentrically in rotatable adjustable sleeves 15 and 16.

Figure 2 is a section through the adjusting arrangement, showing the eccentric arrangement of the roller shafts 11 and 12 in the adjusting sleeves 15 and 16 with a mean centre spacing.

Figure 3 is a section through the toothed wheels 9, 10 and the driving wheels 17, 18 with the drive wheels 17,18 ofthe roller shafts 11, 12 at the mean centre spacing. Since the eccentricity e of the axis of the roller shafts 11, 12 relative to the axis of the adjusting sleeves 5, 16 is identical with the centre spacing a between the internal and external teeth of which 9, 17 and 10, 18 and since the axes of the gear shafts 6,8 coincide with the axes of the associated adjusting sleeves 15,16, the teeth will remain exactly in engagement when the roller shafts 11,12 are adjusted by turning the adjusting sleeves 15, 16 by means of the drive shown in Figure 2 provided that the bearings have no play.In practical operation, however, the bearings of the shafts 11, 12 and 6,8 have clearances depending on their functioning, and these clearances lead to changes in the centre spacing of the external and internal teeth, causing trouble in engagement.

Figure 4 is a diagram showing the correction of the internal and external teeth, for cases where the gear shafts 6,8 run in bearings almost free from play and the roller bearings 11, 12 run in radial journal bearings with play dependent on their functioning, taking the upper rim shaft 8 as an example. The lower rim shaft 6 is corrected in a similar way. The non-corrected arrangement is shown in thin lines. If the roller shaft 12 is mounted without play, the pitch circle 19 for the drive wheel 18 rolls along a pitch circle 20 over the entire adjustment range, and the centre of the drive wheel 18 moves along a track 21 with a radius equal to the eccentricity e.

As a result of the bearing clearances of the roller shafts 11, 12 a theoretical path 21 of the drive wheel 18 changes to the path 21'; the exact centre spacing over the entire adjusting range is achieved only at the point of intersection of the paths 21 and 21'. The internal and external teeth are corrected by shifting the axis of the gear shaft 8 from an axis 22 of the eccentric sleeve to a position 23 in a housing 24 of the gearing case 3. In this way the pitch circle 20 of the internally toothed wheel 10 of the rim shaft 8 is shifted, so that the pitch circle 19, shifted by the load on the shaft 12 towards the pitch circle 19' of the drive wheel 18 of the shaft 12, is exactly at a tangent to the pitch circle 20' of the internally toothed wheel 10 of the shaft 8 over the entire adjusting range.

Another possibility of avoiding damage to teeth when there is trouble in engagement isto chamfer the heads of the internal and external teeth.

As result of the correction of the internal and external teeth according to the invention, damage in the internal and external teeth caused by trouble in engagement is avoided over the whole adjusting range, and consequential damage in the entire rolling stand is prevented. Furthermore, utilisation of the hard metal rolls over the entire adjusting range is ensured, i.e. durability until the hard metal rolling discs are discarded is increased.

Claims

1. A drive transmission for driving a spindleless rolling stand with adjustment means for effecting adjustment of the roller shafts, in which said roller shafts are provided with externally toothed drive wheels and mounted in eccentric adjusting sleeves in a roller case, the drive wheels thereof engaging with internally toothed wheels of gear shaft provided in a gear case, said roller case and gearing case being arranged in a common housing, the axes of the internally toothed wheels of the gear shafts being located eccentrically of the axes of the eccentric adjusting sleeves in a housing of the gearing case, the pitch circles of the drive wheels of the roller shafts being at a tangent to the pitch circles of the internally toothed wheels of the gear shafts over the entire adjusting range, and the shifting of the axes being dependent on the roller displacement in the region of the teeth, resulting from the loads and clearnaces necessitated by the operation.

2. A drive transmission for driving a spindless rolling stand, substantially as hereinbefore decribed with reference to and as illustrated in the accompanying drawings.