Toothed coupling

The invention relates to a toothed coupling, especially a double toothed coupling, for rail vehicles, essentially consisting of a coupling housing (2) and at least one coupling component (3, 4) fitted inside the coupling housing (2), the coupling component has first teeth (9, 10) in its peripheral region (7) and the coupling housing has second teeth (11, 12) in its peripheral region (8) which form engaging teeth (13, 14) with the first teeth of the coupling component (3, 4) which are movable in relation to one another, and there is at least one annular disk-shaped support cover (21, 22) protecting the engaging teeth (13, 14) at the respective faces (19, 20) between the coupling housing (2) and the coupling component (3, 4). A toothed coupling is to be provided in which an exchange of media and, with the coupling rotating, irregular running, imbalance and wear of the sealing elements is prevented. To achieve this, there is at least one axial corrugated pipe (18, 47) positioned between the coupling housing (2; 5, 6) and each coupling component (3, 4) secured to at least one of both parts (2, 3; 2, 4 or 5, 3; 6, 4) which seals engaging teeth (13, 14) and also resiliently sets a predetermined position of the coupling housing (2; 5, 6).

The invention relates to a toothed coupling and in particular to a double
 toothed coupling for rail vehicles, essentially consisting of a coupling
 housing and at least one coupling component fitted inside the housing, the
 coupling component has first teeth in its peripheral region and the
 coupling housing has second teeth in its peripheral region which form
 engaging teeth with the first teeth of the coupling component which are
 movable in relation to one another, and there is at least one annular
 disc-shaped support cover protecting the engaging teeth at the respective
 faces between the coupling housing and the coupling component.
 These toothed couplings are employed in most different areas of motive
 power engineering, such as for connecting a driving shaft to a driven
 shaft, when they consist of two torsionally rigid coupling components and
 when a relative movement occurs between the two shafts due to radial,
 vertical and/or angular displacements which needs to be compensated for by
 the coupling. The relative motion between coupling housing and coupling
 components including shafts, as a result, is transferred to the first and
 second teeth of the engaging teeth.
 A toothed coupling and, in particular, a double toothed coupling for rail
 vehicles is disclosed in publication DE-GM 93 09 829.4 in which internally
 toothed coupling components are connected with an externally toothed
 coupling housing.
 Between coupling housing and internal support cover, a coil spring is
 provided which serves to keep the coupling components in axial position. A
 disadvantage of the coil springs is that during rotation, imbalance and
 wear occur between spring and spring support with the rotating coupling
 due to its freely moving windings.
 The radial faces between the coupling housing and the coupling components
 are completely sealed by means of elastic diaphragm sealing rings with
 convex front ends.
 As the coupling rotates, the radial annular bulging of the diaphragm
 sealing rings may be reversed due to the strong centrifugal force thus
 possibly reducing the service life of the diaphragm sealing rings.
 Moreover, the printing DE 295 06 461 reveals a double toothed coupling in
 which a contact-free gap seal consisting of a cover secured to the
 coupling housing is provided between the coupling housing and the coupling
 components as well as an additional sealing protection cap. In case of
 heavy strain, medium can flow through the still existing gap which finally
 does not represent a complete sealing.
 Since there are generally no centring coil springs inside the coupling,
 ring elements to restrict displacement which are arranged opposite to each
 other with respect to their axial direction and consist of an elastic
 material are provided in order to limit the relative movement of the
 external gear between its internal and external areas; on the long term,
 said ring elements, however, are likely to wear out and are unable to
 centre the coupling.
 A brochure "Bogenzahnkupplungen, Basis Baureihen fur Industrie-, Schiffs-
 und Meerestechnik".sup.1, FIG. 9, printed in 1991, shows a toothed
 coupling featuring a diaphragm sealing ring at the front end and an
 internally mounted dynamic coil spring. Each coil spring is positioned
 between the respective internal flange covers and coupling components
 inside the coupling component chamber. The diaphragm sealing rings mounted
 at front ends provide that the coupling housing is completely sealed
 against the external area of the coupling component. In this embodiment,
 too, imbalance and wear occur as the coupling rotates due to the behaviour
 of the prestressed coil spring.

FNT .sup.1 "Curved teeth coupling, basic series for industrial, shipping and
 marine technology"
 In the international patent application Wo 95/27151 a double coupling is
 disclosed, in which two internal coupling components are enclosed by a
 coupling housing. The internal teeth of the coupling components are
 positioned on a gear ring or gear star with circumferential round openings
 in axial direction which are directed towards the externally located
 support covers and in which the coil springs are arranged in such a way
 that they contact the annular support cover of the coupling housing. Since
 the individual coil springs are fitted in a highly elaborate manner into
 the multi-part support cover which has a conical shape with respect to the
 exterior of the coupling component and in that these support covers are
 screwed to the external face of the coupling so that they can be adjusted,
 they serve to centre the engaging teeth. With this configuration, too,
 media can be exchanged through the existing wedge-shaped tiny gaps at
 front ends between the components of the support cover. In the known
 toothed coupling sealings are subject to wear.
 The aim of the invention therefore is to develop a toothed coupling which
 is designed in such a way that the exchange of media and, with the
 coupling rotating, irregular running, imbalance and wear of the sealing
 elements is prevented.
 This is achieved by the features in claim 1. In the toothed coupling
 according to the generic term in claim 1, between the coupling housing and
 each coupling component, there is at least one axial corrugated pipe
 secured to at least one of both parts which seals the engaging teeth and
 also resiliently sets a predetermined position of the coupling housing.
 Although, depending on how the peripheral regions of coupling housing and
 coupling components are positioned to each other, the engaging teeth and
 the corresponding corrugated pipes can be placed accordingly, i.e. outside
 or within the peripheral region of the coupling housing, the invention
 will be discussed hereunder in detail with respect to a toothed coupling
 in which the peripheral region of the coupling components faces the
 coupling housing.
 Accurate dimensions of the corrugated pipes provide for non-slipping torque
 transmission.
 Through the use of corrugated pipes, it is possible to save several parts
 for sealing and spring support. Referring to the invention, the smoothness
 of running is substantially improved by the shape and arrangement of the
 corrugated pipes.
 The corrugated pipe is preferably shaped in the form of a bellow consisting
 of corrosion-proof material.
 The corrugated pipe may be axially mounted with or without pretension
 between the coupling housing or the coupling housing components connected
 to the coupling housing and one coupling component respectively and, in
 case of axial relative movement of the coupling components, ensures that
 the coupling housing sets to its predetermined position preferably in the
 centre between both coupling components.
 At its outer edge region at the front ends, the corrugated pipe may either
 be fitted with annular or flange-like fastening elements which are
 preferably arranged parallel in relation to each other. The fastening
 elements may consist of a plurality of rings, the outer edge region of the
 corrugated pipe being bonded to one of these rings particularly by
 welding.
 Depending on the rigidity requirements, this corrugated pipe may be
 single-walled or multi-walled, the corrugated pipe preferably has a simple
 shape or is formed in multiple meanders as regards to its longitudinal
 section.
 Depending on the intended strain, the corrugated pipe features an undulated
 geometry in which the outer envelope of the corrugated pipe preferably has
 a cylindrical or tapered shape or the like.
 The radial support cover basically consists of an external fastening
 element and an internal fastening component and, depending on the position
 of the engaging teeth, is connected either to the coupling housing or the
 coupling component and to the corrugated pipe via its internal fastening
 component preferably by means of cramping or welding and largely covers
 the corresponding axial free space at front ends.
 If the corresponding peripheral region of the coupling components is inside
 the coupling housing, the coupling components are provided with an annular
 recess preferably with a cavity-shaped cross section around its
 circumference at the respective front ends with respect to the interior of
 the coupling component in which the corrugated pipe is preferably mounted
 in central direction to the camber centre lines of the coupling component
 teeth and axially in relation to the axis of rotation of the coupling
 housing.
 The external fastening element of the support cover may be secured to the
 coupling housing or the coupling halves, as the case may be, preferably by
 means of a releasable locking facility.
 The external free spaces at front ends and the corresponding internal free
 spaces which represent the interior of the coupling component are
 interconnected by means of at least one pressure compensation opening
 through which lubricants and in particular oil as well as air can be
 exchanged for pressure compensation.
 The free spaces allocated to each other serve the purpose of a pneumatic
 spring since they are completely sealed by means of the elastic corrugated
 pipe.
 Irrespective of the design of the toothed couplings and in particular
 double toothed couplings, this invention makes it possible to completely
 seal the internal chambers between couplings components and coupling
 housing thus preventing media flowing from the inside to the outside and
 vice versa; lubricants can neither flow out of the free spaces nor can
 media flow into the engaging teeth, which largely increases the service
 life of the coupling. With the invention, both internal and external areas
 of the cambered teeth (coupling stars) of the coupling components are
 protected against wear on the long term. This aims at a toothed coupling
 in which lubrication is designed to provide long service.
 Further, the corrugated pipe which is secured to the coupling housing and
 to at least one of the coupling components features closed walls and
 provides sealing and resilient properties thus enabling a simple
 construction of the coupling components so that material costs and
 assembly time can be reduced. If desired, the corrugated pipes can be
 positioned successively, one inside the other or parallel to each other in
 the recesses of the coupling components.
 In addition, the engaging teeth of a coupling may preferably comprise one
 straight internal tooth gearing of the coupling housing and an engaging
 cambered external tooth gearing of the coupling component.
 The invention can be employed in all toothed couplings irrespective of the
 design of the coupling components and the coupling housing and
 irrespective of where the teeth of the engaging teeth are positioned and
 how their design has been executed.
 In relation to the invention and as described above, the corrugated pipes
 may also be secured to the coupling housing and the coupling components
 outside the peripheral region of the coupling housing; the coupling
 component teeth (first teeth) are designed as internal tooth gearing and
 the coupling housing teeth (second teeth) are designed as external tooth
 gearing with the peripheral regions of the coupling components enclosing
 the coupling housing at front ends and at its exterior. The coupling
 housing is positioned between the internally toothed coupling components
 as an externally toothed intermediary piece.
 Further developments and suitable embodiments of the invention are
 described in further sub-claims.

In the following FIGS. 1 to 5, the same reference signs are employed for
 similar parts.
 Referring to the invention, FIG. 1 depicts a toothed coupling and in
 particular a double toothed coupling 1 with a coupling housing 2 and two
 coupling components 3,4 which are, for example, developed as one part and
 are positioned in the coupling housing 2; the coupling components 3,4 each
 determine one internal coupling component chamber 17,65 inside the
 coupling housing 2 with a flange area 56 in between. For practical
 reasons, the coupling housing 2 consists of two, largely symmetric
 coupling halves (also called coupling sleeves or bushes) 5,6 bolted
 together by means of fit bolts 23 at flanges 42,43 which are provided at
 the coupling halves 5,6 and positioned opposite to one another comprising
 a radially positioned internal cover 45,46 sealing both internal coupling
 component chambers 17,65. At their external peripheral region 7, the
 coupling components 3,4 feature an external tooth gearing 9,10 (first
 teeth) with cambered coupling teeth. Coupling housing 2 features an
 internal tooth gearing 11,12 (second teeth) at its internal peripheral
 region 8. External tooth gearing 9,10 of coupling components 3,4 and
 internal tooth gearing 11,12 of coupling housing 2 each form engaging
 teeth 13,14 in the coupling halves 5,6, in which similar to the relative
 movement between the coupling components 3,4 and the coupling housing 2,
 the internal tooth gearing 12,13 and the external tooth gearing 9,10 are
 accordingly movable in relation to one another. The relative movement
 occurs in case of axial and/or angular displacement of the coupling
 components 3,4 in relation to the coupling housing 2 or the coupling
 halves 5,6 as the case may be. At axial faces 19,20 and between coupling
 halves 5,6 and the corresponding coupling component 3,4, there exists a
 circular outer free space 15 or 16 as the case may be.
 At faces 19,20 of the coupling housing 2, there are support covers 21,22
 which are basically shaped in the form of an annular disc and also feature
 a radial external fastening element 28,29 and a radial internal fastening
 component 60,61. The support covers 21,22 are secured to coupling housing
 2 or, as the case may be, coupling halves 5,6 by means of their external
 fastening element 28,29 thus largely covering the axial free spaces 15,16
 at the front end.
 Referring to the invention, an axial corrugated pipe 18,47 is positioned
 between the coupling housing 2 or, as the case may be, coupling halves 5,6
 and each coupling component 3,4 which is also secured to both parts 5,3
 and 6,4 and seals the corresponding engaging teeth 13,14 and also
 resiliently sets a predetermined position of the coupling housing 2.
 The corrugated pipe 18,47 is axially mounted between coupling halves 5,6
 and one coupling component 3,4 and, with the coupling components 3,4
 axially moving in relation to one another, sets coupling housing 2 to its
 predetermined central position between both coupling components 3,4. The
 corrugated pipe may be prestressed, i.e. it can be in a prestressed or
 relaxed condition with respect to pressure or tension.
 Accurate dimensions of the corrugated pipes 18,47 provide non-slipping
 torque transmission.
 The corrugated pipe preferably shaped in the form of a bellow consisting of
 corrosion-proof material.
 At both outer edge regions, the corrugated pipe 18,47 is equipped with
 annular flange-like fastening elements 53,54 or with 40,41 and in
 particular bellow-type flanges which are preferably arranged parallel to
 one another. The corrugated pipe 18,47 may be bonded to its fastening
 elements 53,54 or 40,41 as the case may be particularly be welding.
 The corrugated pipe 18,47 can be single-walled or multi-walled.
 FIG. 2 is a magnified section of corrugated pipe 47 in central mounting
 position, however, reference is also made to the drawing on the left side
 in FIG. 1.
 The corrugated pipe 47,18 may also have a simple shape or be formed in
 multiple meanders with respect to its longitudinal section.
 Depending on the intended strain on clutch 1, it is possible to adjust the
 undulated geometry. Similarly, the outer envelope 55 of corrugated pipe
 47,18 may also have a shape different from a cylindrical one.
 The corrugated pipes 47,18 are secured to the internal fastening components
 60,61 of support covers 22,21 at front ends.
 At faces 20,19 and directed to the internal coupling component chamber
 65,17, each coupling component 4,3 is provided with an annular or circular
 recess with cavity-shaped cross-section 50 or 51 in which the corrugated
 pipe 47 or 18 as the case may be is preferably mounted in central position
 to the cambered centre lines 52 or 48 as the case may be of the coupling
 component gearing 10,9 and axially to the corresponding support covers
 22,21 in a prestressed manner. The corrugated pipes 18,47 may be mounted,
 for example, by bolting, welding or clamping or the like and the weld of
 at least one outer edge side of the corrugated pipe 47,18 can be extended
 through support covers 22,21 preferably without an own fastening element.
 For practical reasons, the outer free spaces 16,15 can be connected to the
 corresponding internal coupling component chambers 65,17 representing the
 internal free spaces by means of at least one pressure compensation
 opening 30 (FIG. 2), 31 (FIG. 3) for the purpose of throttling so that
 lubricant and in particular oil as well as air can flow through the
 opening thereby compensating for the pressure.
 The pressure compensation openings 30,31 are positioned in the
 corresponding connecting area of a protruding ring of external tooth
 gearing 49,44 preferably in paraxial direction between the outer free
 space 16,15 and the internal coupling component chamber 65,17.
 On the other hand, the free spaces 16,65 or 15,17 as the case may be, which
 are allocated to each other, act as a pneumatic spring.
 It is possible to adjust the performance of the pneumatic spring by
 changing the dimensions of the cross-sectional shape of pressure
 compensation openings 30,31.
 To fill the internal coupling component chambers 65,17 with the lubricant
 oil, filling holes 58,57 which can be closed with a sealing plug 62 each,
 in particular with a screw plug, are provided in coupling housing 2 or, as
 the case may be, in coupling halves 6,5.
 FIG. 3 discloses a magnified drawing of one part of the section according
 to FIG. 1. This FIG. 1 shall also be taken into account for explanation.
 The support covers 21,22 are each secured to the coupling halves 5,6 by
 means of a releasable locking element 39,38 basically consisting of an
 external radial snap ring groove 34,35 in the coupling halves 5,6, a
 radial internal snap ring groove 32,33 in support covers 21,22 and a
 resilient ring, in particular spring ring 24,25, which engages with both
 opposite snap ring grooves 32,34 or 33,35 as the case may be during
 locking. The securing resilient rings 24,25 have a positive fit in
 relation to the snap ring grooves 32,33,34,45.
 In order to release the locking of support covers 21,22, there are at least
 three openings and in particular threaded bores 26 or, as the case may be
 27 which are arranged in a 120.degree. angle each preferably as radial
 bore at the outside of the external fastening elements 29,28.
 However, the support covers 21,22 may also be secured by simply screwing
 the external fastening elements 28,29 to the coupling halves 5,6 at front
 ends.
 Similarly to FIG. 2,3, FIG. 4 shows a section in which the corrugated pipe
 47 is secured to support cover 66 and to coupling component 4 in a simple
 mounting manner. For example, on the one hand, the corrugated pipe 47, at
 its face, may be directly secured, in particular by welding or clamping,
 to the corresponding support cover 66 at connection point 67 and within
 its outer edge region without a bonded fastening element.
 On the other hand, the corrugated pipe 47 may feature an annular fastening
 element 68 positioned internally at the front ends at the other outer edge
 region and directed towards coupling component 4 which may consist of
 several rings as, for example, an external clamping ring 69 welded to the
 corrugated pipe 47 and an internal adjusting ring 70 fitted into and
 guided inside said clamping ring, said fastening element being secured to
 coupling component 4 by means of threaded drill inside adjusting ring 70
 and corresponding screw locking 71 so that the clamping ring 69 is locked
 between adjusting ring 70 and coupling component 4.
 In addition to the bonded connection of corrugated pipe 47 to the internal
 fastening component 60 of the corresponding support cover 66 which is easy
 to mount, also its external fastening element 28 may have a simple shape
 and, in particular, a flange-like shape and may be secured to the
 externally flanged coupling half 6, e.g., by a screwing 72. In double
 toothed couplings, the second corrugated pipe 18 is positioned in the same
 way.
 While the ways of mounting the corrugated pipe 18,47 to support covers
 21,22 or 66 and to coupling components 3,4 are discussed with reference to
 the drawings in FIG. 2,3,4, it is to be understood that the mounting
 possibilities are not restricted to these drawings.
 Referring to FIG. 5, toothed coupling 1 in FIG. 1 related to the invention
 is depicted while being radially displaced.
 In that the coupling components 3,4 (shafts) are displaced in relation to
 each other, a relative movement with respect to coupling housing 2 or
 coupling halves 5,6 as the case may be occurs which is represented by
 displacement angle a between the rotational axis 64,63 of the coupling
 components and the rotational axis 59 of the coupling housing
 respectively.
 During displacement, the coupling housing 2 tilts in relation to the
 reference points on the camber centre line 36,37 and in this way, the
 corrugated pipes 18,47 are subject to plastic deformation.
 Due to the initial tension of corrugated pipes 18,47 and the pneumatic
 cushions, it is possible to dispense with stopper elements not only in the
 lateral external regions of engaging teeth 13,14 but also in the entire
 toothed coupling 1 related to the invention in general.
 The invention may also be employed in toothed couplings and in particular
 in double toothed couplings in which the engaging teeth consist of
 cambered second teeth (external tooth gearing) of the coupling housing or
 the coupling halves as the case may be and straight first teeth (internal
 tooth gearing) of the coupling components.

Reference list
 1 double toothed coupling
 2 coupling housing
 3 coupling component
 4 coupling component
 5 coupling half
 6 coupling half
 7 peripheral region
 8 peripheral region
 9 external tooth gearing
 10 external tooth gearing
 11 internal tooth gearing
 12 internal tooth gearing
 13 engaging teeth
 14 engaging teeth
 15 free space
 16 free space
 17 internal coupling component chamber
 18 corrugated pipe
 19 face
 20 face
 21 support cover
 22 support cover
 23 fit bolts
 24 ring
 25 ring
 26 opening
 27 opening
 28 external fastening element
 29 external fastening element
 30 pressure compensation opening
 31 pressure compensation opening
 32 internal snap ring groove
 33 internal snap ring groove
 34 external snap ring groove
 35 external snap ring groove
 36 reference point on the camber centre line
 37 reference point on the camber centre line
 38 locking element
 39 locking element
 40 fastening element
 41 fastening element
 42 flange
 43 flange
 44 external tooth gearing ring
 45 internal cover
 46 internal cover
 47 corrugated pipe
 48 camber centre line
 49 external tooth gearing ring
 50 recess
 51 recess
 52 camber centre line
 53 fastening element
 54 fastening element
 55 envelope
 56 flange area
 57 filling hole
 58 filling hole
 59 rotational axis of coupling housing
 60 internal fastening component
 61 internal fastening component
 62 sealing plug
 63 rotational axis of coupling component
 64 rotational axis of coupling component
 65 internal coupling component chamber
 66 support cover
 67 connection point
 68 fastening element
 69 clamping ring
 70 adjusting ring
 71 screw locking
 72 screwed connection
 .delta. displacement angle