GB2159252A

GB2159252A - Hydrodynamic coupling

Info

Publication number: GB2159252A
Application number: GB08511720A
Authority: GB
Inventors: Jurgen Liebe; Konrad Lubik; Klaus Nolz
Original assignee: JM Voith GmbH
Current assignee: JM Voith GmbH
Priority date: 1984-05-16
Filing date: 1985-05-09
Publication date: 1985-11-27
Also published as: FR2564548A1; FR2564548B1; GB8511720D0; DE8414929U1

Abstract

In a coupling of the type having a primary wheel (13) and a secondary wheel (12) each equipped with buckets, which together define a working area (9), and in which one bucket wheel (13) is supported on the other bucket wheel (11,12) via at least one bearing (15,16); which bearing is sealed by means of a seal (32,33) against the working area, the surfaces of the coupling components in contact with working liquid, in particular the bucket wheels (12,13), have a metal oxide layer. Thus, corrosion damage by the coupling working liquid, which is preferably water or other non- combustible liquid. is avoided by the metal oxide coating which may, e.g. be produced by electrolytic oxidation. Preferably those coupling components (12,13) coated with the metal oxide layer are of light metal, such as aluminium. <IMAGE>

Description

SPECIFICATION Hydrodynamic coupling The invention relates to a hydrodynamic coupling of the type havng a primary wheel and a secondary wheel each equipped with buckets, which together define a working area, and in which one bucket wheel is supported on the other bucket wheel via at least one bearing; which bearing is sealed by means of a seal against the working area. Such a coupling serves for the power transmission from a drive motor to a processing machine, preferably in mining installations. No combustible liquids, e.g. oil, may be used as coupling working liquid, as is known. instead the coupling has to be filled with water or a similar noncombustible liquid. Such liquids have, of course, the disadvantage that they can not be ued as libricants for the bearings. Therefore the bearings are sealed against the working area by means of a seal.

A further advantage of non-combustible liquids consists in that in operation they cause corrosion damage on the internal surfaces of various coupling components, in particular bucket wheels.

From these operational faults and operational defects can result.

According to the invention, a hydrodynamic coupling of the type disclosed above is characterised in that the surfaces of the coupling components in contact with working liquid, in particular the bucket wheels (12, 13), have a metal oxide layer.

Thus, corrosion damage can be avoided by the metal oxide coating which may, for example, be produced by electrolytic oxidation. Particularly good resistance to corrosion is achieved by the respective coupling components being manufactured from light metal, e.g. aluminium, in a per se known way. For, when oxidation is formed, light metals provide a particularly stable oxide coating which is able to protect effectively the metal underneath it against the attack of working liquid.

One embodiment of hydrodynamic coupling in accordance with the invention is shown in longitudinal section in the accompanying drawing.

The coupling shown has a power take-off shaft 10, on which the hub 11 of the secondary bucket wheel 1 2 is fixed. The primary bucket wheel 1 3 is rotatably supported together with the coupling shell 14 fixed there on by roller bearings 1 5 and 1 6. On the outside or the primary bucket wheel 1 3 is fixed a drive bushing 1 7 which limits a retardation chamber 1 8. The drive bushing 1 7 can be connected with a drive shaft not shown.

The external diameter of the buckets (the same size for both bucket wheels 1 2 and 13) is marked by A, the internal diameter, of the buckets of the primary wheel by B and the internal diameter of the buckets of the secondary wheel by C. The radial median plane of the coupling, which runs along the gap between the bucket wheels, is marked by E.

The primary bucket wheel 1 3 has a wheel disc 1 9 with a wheel hub 20 formed thereon.

The wheel disc 1 9 is relatively far from the median plane E. On the primary bucket wheel 13 a recess 21 is incorporated in the radially internal area of the buckets of the median plane E. A disc 22 provides a flange 23 extending in the axial direction towards the secondary wheel 1 2. Directly next to the median plane E is located throttle plate 24 which, together with the disc 22, is fixed on the primary bucket wheel and whose external diameter is approximately the same as the external diameter D of the disc 22.

The disc 22 with its flange 23 and the throttle plate 24 define the so-called baffle area 25. Thus, when there is significant slippage, working liquid from the secondary bucket wheel 1 2 can penetrate the baffle area 25, the throttle plate 24 having several flow apertures 26. In addition, an annular clearance can be provided between the throttle plate 24 and the secondary hub 11. Betwen the flange 23 and the throttle plate 24 is provided a distance "a" which is only relatively small.

In the wheel disc 1 9 of the primary bucket wheel 1 3 are located numerous wide flow channels 27, of which only two are visible.

Through these channels, the intermediate space 39 located between the wheel disc 1 9 and the disc 22 is a component of the retardation chamber 18.

The working area formed by the two bucket wheels 1 2 and 1 3 is marked by 9. Its radially internal area is connected via channels 28, which are guided through the wheel disc 19, with the radially internal area of the retardation chamber 1 8. This ensures that through these channels 28 an overflow of liquid from the working area 9 into the retardation chamber 1 8 only occurs when the coupling is at a standstill. When it is restarted the liquid can flow back only via choke bores 29 from the retardation chamber into the working area.

In normal operation, i.e. when the processing machine to be driven runs at its normal speed, the coupling works with only slight slippage. The ensuing toroidal flow is marked by the arrows 8. The arrows 7 on the other hand represent the flow occurring with significant slippage in the secondary bucket wheel 12.

To seal the interior of the coupling to the outside, gasket rings 30, 31 are provided on the outside of the roller bearings 1 5 and 1 6.

In the coupling in accordance with the invention, water or a similar non-combustible liquid is used as the working liquid instead of oil which is generally used. Therefore, sealing rings 32, 33 are also arranged on the interior of the roller bearings 1 5 and 1 6. Moreover, all surfaces of the coupling components coming into contact with the working liquid are protected by a metal oxide layer against the corrosive attack of the water.

Claims

1. A hydrodynamic coupling of the type having a primary wheel (13) and a secondary wheel (12) each equipped with buckets, which together define a working area (9), and in which one bucket wheel (13) is supported on the other bucket wheel (11, 12) via at least one bearing (15, 16); which bearing is sealed by means of a seal (32, 33) against the working area, characterised in that the surfaces of the coupling components in contact with working liquid, in particular the bucket wheels (12, 1 3), have a metal oxide layer.

2. A hydrodynamic coupling according to Claim 1, characterised in that those coupling components (12, 13), whose surfaces in contact with working liquid have a metal oxide layer, are manufactured from light metal, such as aluminium.

3. A hydrodynamic coupling constructed, arranged and adapted for use substantially as hereinbefore described with reference to the accompanying drawing.