Side shaft journal for a differential gear with adjusted joint component of a universal-joint drive shaft

The invention relates to an assembly comprising a side shaft journal and a joint component of a CV-jointed shaft, and a method of making the same. The assembly provides a side shaft journal (31) for a differential gear, comprising an inner end which can be inserted into the differential gear, said inner end having an outer toothing (33) and a ring groove (23) for receiving a locking ring (24) by means of which the inner end can be removably connected to a side shaft wheel (25) of the differential gear. Said side shaft journal also comprises an outer end which can be connected to a joint component (41) of a universal-joint drive shaft, said outer end having a toothing (32) and formed elements (33, 34, 40) for receiving axial securing elements, which can be non-destructively removed, for the joint component. The shaft journal (31) is configured as a hollow shaft.

BACKGROUND OF THE INVENTION
 The invention relates to an assembly consisting of a side shaft journal for
 a differential drive and of a joint component of a CV-jointed shaft, which
 joint component is connected to the side shaft journal. The invention also
 relates to a unit consisting of a differential drive and two side shafts
 with at least one such assembly consisting of a side shaft journal and a
 joint component.
 Prior art side shaft journals of differential drives of a first type
 comprise an outer flange for bolting on a joint component of an adjoining
 CV-jointed shaft. The disadvantage of such shaft journals is that the
 joint component has to be adapted accordingly, i.e. it must be designed to
 receive bolting connecting means which, as a rule, are plugged-through
 bolts. To be able to receive the threaded holes, the joint component needs
 to have additional material away from the functional parts, as a result of
 which the joint component becomes heavier and more expensive to produce.
 Furthermore, there are prior art side shaft journals of a second type
 wherein--in order to avoid the above-mentioned disadvantages--the shaft
 journal is integral with the joint component of the adjoining CV-jointed
 shaft. Assembling constant velocity joints is a complex operation which
 cannot be undertaken when the shaft journal has already been inserted into
 the differential drive. The resulting disadvantage is that it is only
 during the mounting of the CV-jointed shafts at the vehicle, that the
 differential drive can be sealed outwardly by inserting the shaft journal
 and that it is only after completion of this operation that the
 differential drive can be filled with lubricant. This is highly
 disadvantageous for the production sequences of the vehicle.
 Furthermore, there are prior art side shafts whose outer end is provided
 with shaft toothing which is used in a plug-in connection for the joint
 component of the adjoining CV-jointed shaft. As a rule, such shaft
 journals are directly axially secured relative to the drive housing of the
 differential drive.
 SUMMARY OF THE INVENTION
 It is the object of the present invention to provide an assembly of the
 above-mentioned type with a side shaft journal which comprises improved
 attaching and axial securing means, which is lighter in weight and easier
 to produce.
 The objective is achieved by the combination of characteristics in
 accordance with the invention:
 an assembly consisting of a side shaft journal for a differential drive and
 of a joint component of a CV-jointed shaft which joint component is
 connected to the shaft journal, with the shaft journal comprising an inner
 end insertable into the differential drive and having outer shaft toothing
 and an annular groove for receiving a securing ring, by means of which
 annular groove the inner end is releasably connectable to a side shaft
 gear of the differential drive, and further comprising an outer end which
 is connectable to the joint component and provided with shaft toothing and
 formations for receiving nondestructively releasable axial securing means
 for the joint component, with the shaft journal being provided in the form
 of a hollow shaft.
 By providing the inventive embodiment with a side shaft journal in the form
 of a hollow shaft, it is possible to achieve a considerable reduction in
 weight as compared to prior art shaft journals which, at most, are
 partially hollow. The transition to the shaft toothings as connecting
 means at both ends, i.e. for providing a connection with the side shaft
 gear and with the joint component, leads to a further substantial
 reduction in weight as compared to prior art flange shaft journals. By
 using a retaining ring connection for axial securing purposes relative to
 the side shaft gear, it is possible to achieve a simple and secure
 assembly which turns the differential drive with the inserted shaft
 journal into a sealed system which is fully filled with lubricant and
 which, in a fully functioning condition, can be mounted on the vehicle. By
 designing the interface relative to the joint component as a releasable
 plug-in connection, it is also possible, subsequently, in the course of
 the production of the vehicle and for repair purposes at a later stage, to
 mount the CV-jointed shafts supplied in a fully functioning condition and
 filled with lubricant.
 The axial securing means between the outer end of the shaft journal and the
 joint component are designed in such a way that the connection can be
 released without the retaining ring connection between the shaft journal
 and the side shaft gear being subjected to axial forces. In this way, any
 unintentional removal of the shaft journal, which would destroy the sealed
 differential drive system, is rendered impossible.
 By providing the inventive shaft journal in the form of a hollow shaft, it
 is possible-to produce the shaft journal by a non-chip-producing forming
 process which is a low-energy process. Such processes wherein the shaft
 toothing can also be finished by a non-chip producing forming method are
 round hammering or round kneading or certain stretching methods, starting
 from the raw material. The open inner end of an assembly produced in this
 way has to be closed by a cover, so that the differential is sealed as
 required. In addition, provided the length/diameter ratio is not too
 extreme, the inventive shaft journal can be produced by deep drawing, in
 which case, in a particularly advantageous way, the base of the product
 already provides the means for internally sealing the differential.
 As far as the design of the shaft toothing at the outer end is concerned,
 i.e. the connection with the joint component, it is possible to provide
 either outer shaft toothing which is inserted into an overlapping sleeve
 portion of the joint component, or inner shaft toothing which is
 overlappingly slid on to a journal or cylindrical portion of the joint
 component. The respective joint component can be provided with a base
 which seals the joint at one end and which is followed by a sleeve for
 providing a plug-in connection substantially improves the overall system
 of the differential drive with the adjoining CV-jointed shafts.
 As regards releasable connecting means between the outer end of the shaft
 journal and the joint component, a few advantageous examples will be
 listed below:
 One possibility consists in producing a retaining ring connection with
 suitable annular grooves in the region of the shaft toothing, which
 grooves jointly receive a retaining ring.
 A further embodiment consists in providing a wedged annular groove in the
 inner part of the plug-in connecting means into which groove there are
 threaded conically tapered pins from the outside through the outer part of
 the plug-in connecting means, which pins rest against the flanks of the
 keyway. If the pins rest against only one of the flanks, the parts of the
 plug-in connecting means can be clamped relative to one another due to the
 respective end faces mutually resting against one another.
 A further embodiment may comprise a union nut which is axially supported on
 the slid-in part of the plug-in connecting means via a securing ring and
 which extends over the slid-on part of the plug-in connecting means and is
 secured thereto by means of a thread. Again, axial clamping can be
 effected by opposed end faces contacting one another between the parts
 connected to one another by the plug-in connecting means.
 If the shaft journal is slid into a sleeve portion of the joint component,
 it is proposed according to a particularly advantageous embodiment to
 provide a bore in said sleeve, which bore leads to the axial abutment
 faces between the parts. A wedge-shaped tool can then be passed through
 the bore or aperture for driving the connection apart, if necessary,
 without any axial forces being transferred to the retaining ring
 connection between the shaft journal and the side shaft gear.
 When the outer open end of the shaft journal extends over an attaching
 element of the joint component, the axial abutment region is usually
 positioned outside the differential drive and is freely accessible, so
 that a wedge-shaped tool can easily be applied.
 In the case of the above-mentioned inventive production methods for the
 shaft journal, forming takes place in such a way that the wall thickness
 substantially remains the same. In particular, for weight optimizing
 purposes in the case of a stepped shaft journal, it is proposed that a
 constant resistance moment is set along the length by means of the all
 thickness/diameter ratios. A further aspect is that the degree of forming
 should be as low as possible so that cold-forming is also possible. For
 this purpose, it could be advantageous to widen the outer end of the shaft
 journal, whereas the outer diameter of the inner shaft end is optionally
 reduced in connection with producing the outer shaft toothing.
 The invention provides a functionally advantageous component which is cheap
 to produce and which substantially improves the overall system of the
 differential drive with the adjoining CV-jointed shafts.
 To the extent that this has not yet been explained above, special reference
 is made to preferred embodiments listed in the sub-claims. All preferred
 embodiments may be used alone or in any possible combination thereof.

DETAILED OF THE INVENTION
 To the extent that the details in FIGS. 1 to 5 are identical, they have
 been given the same reference numbers and will be described jointly.
 A differential drive is shown in the region where a shaft passes through
 part of the drive housing 11 with a shaft passage aperture 12. An angular
 roller bearing 13 is inserted into the through-aperture 12 and secured
 axially outwardly by a securing ring 14. A differential carrier 15
 positioned inside the housing 11 is supported in the angular roller
 bearing 13. The differential carrier 15 is shown only slightly beyond its
 central plane M. In the central plane there is inserted a radial bearing
 journal 16 which supports two differential bevel gears 17, 18. As can be
 seen, the differential carrier 15 is provided with a sleeve projection 19
 which forms a plug-in aperture 20 for a side shaft journal which is
 referred to separately in the individual drawings. The side shaft journal
 is supported on a friction bearing in the plug-in aperture 20. The inner
 end of the side shaft journal is closed by a cover 21. At its inner end
 extending into the differential carrier 15, the side shaft journal
 comprises outer shaft toothing 22 and an annular groove 23 holding a
 retaining ring 24. On said inner ring, there is positioned one of two side
 shaft bevel gears 25 provided with corresponding inner shaft toothing 26
 in which there is formed an annular groove 27. The side shaft bevel gear
 25 is supported relative to the differential carrier 15 by two sliding
 plates 28, 29. The outer end of the side shaft journal which emerges from
 the differential housing 11 is sealed relative thereto by a composite seal
 30 positioned in the through-aperture 12. The outer free end of the side
 shaft journal is connected to the outer joint part (referred to separately
 in the individual drawings) by means of plug-in connecting means. The
 assembly of the side shaft bevel gear 25 with the side shaft journal has
 to be assumed to be duplicated in a symmetric arrangement in the
 differential carrier 15. The driving means for rotatingly driving the
 differential carrier 15 inside the differential housing 11 are to be
 assumed to be provided on the outside of the second half of the
 differential carrier (not shown).
 In FIG. 1, the side shaft journal 31 is provided in the form of a hollow
 shaft which, in two steps, changes from a portion with a larger diameter
 positioned outside the housing 11 to the portion with the smaller diameter
 inserted into the side shaft bevel gear 25. At the outer end, there is
 provided an outer shaft toothing 32 provided with an annular groove 33
 which is engaged by a retaining ring 34. On to the outer end, there is
 slid the outer joint part 41 by means of a cylindrical projection 42 which
 is provided with inner shaft toothing 36 which also comprises an annular
 groove 37. The latter is also engaged by the retaining ring 34 and thus
 axially secures the outer joint part 41 relative to the side shaft journal
 31 in both directions.
 The cylindrical projection 42 is provided with a radial bore 38 which is
 closed by a plug 39 made of plastics. After the plug 39 has been removed,
 a wedge-shaped tool can be inserted into the annular gap 40 between the
 base part 43 of the outer joint part 41 and an end face 35 of the side
 shaft journal 31. In this way, the retaining ring connection can be
 released without any axial forces being applied to the retaining ring
 connection between the side shaft journal 31 and the side shaft bevel gear
 25. On the outside of the cylindrical projection 42, there are provided
 two protective covers 44, 45 for protecting the composite seal 30.
 In FIG. 2, the side shaft journal 51 is provided in the form of a hollow
 shaft which, in two steps, changes from a portion with a larger diameter
 positioned outside the housing to a portion with a smaller diameter
 inserted into the side shaft bevel gear 25. At the outer end, there is
 provided an outer shaft toothing 52 which comprises a keyway 53. On to the
 outer end, there is slid the outer joint part 61 by means of a cylindrical
 projection 62 which comprises an inner shaft toothing 56.
 The cylindrical projection 62 is provided with a radial bore 58 into which
 there is threaded a conical bolt 59, On the circumference, there are
 provided three bores with three bolts which engage the keyway 53 in the
 flank located towards the end and thus secure the outer joint part 61
 relative to the side shaft journal 51, with an end face 55 of the side
 shaft journal being in abutment with the base part 63 of the outer joint
 part 61. The keyway connection can be released without any axial forces
 being applied to the retaining ring connection between the side shaft
 journal 51 and the side shaft bevel gear 25. On the outside of the
 cylindrical projection 62 there are provided two protective covers 44, 45
 for protecting the composite seal 30.
 In FIG. 3, the side shaft journal 71 is provide in the form of a hollow
 shaft which, in two steps, changes from a portion with a larger diameter
 positioned outside the housing 11 to the portion with the smaller diameter
 inserted into the side shaft bevel gear 25. At the outer end, there is
 provided an outer shaft toothing in front of which there is provided an
 annular groove 73 which is engaged by a securing ring 74. On to the outer
 end, there is slid an outer joint part 81 means of a cylindrical
 projection 82 which comprises an inner shaft toothing 76. The securing
 ring 74 holds a disc 77 which supports a union nut 78 which, on its
 outside, comprises key faces 79. Said union nut 78 extends over the
 cylindrical projection 82 and is threaded thereto. The end face 75 of the
 side shaft journal 71 is in abutment with the base part 83 of the outer
 joint part. The union nut connection can be released without any axial
 forces being applied to the retaining ring connection between the side
 shaft journal 71 and the side shaft bevel gear 25. On the outside of the
 union nut 78, there is positioned a protective cover 46 for protecting the
 composite seal 30.
 In FIG. 4, the side shaft journal 91 is provided in the form of a hollow
 shaft which, in two steps, changes from a portion with a larger diameter
 positioned outside the housing 11 to the portion with the smaller diameter
 inserted into the side shaft bevel gear 25. At the outer end, there is
 provided an outer shaft toothing 92 in front of which there is provided an
 annular groove 93 which is engaged by a securing ring 94. On to the outer
 end, there is slid an outer joint part 101 by means of a cylindrical
 projection 102 which comprises an inner shaft toothing 96. The securing
 ring 94 holds a disc 97 which supports a union nut 98 provided with bores
 for applying a hook-shaped key.
 The union nut 98 extends over the cylindrical projection 102 and is
 threaded thereto. An end face 95 of the side shaft journal 91 is in
 abutment with a base part 103 of the outer joint part. The union nut
 connection can be released without applying any axial forces to the
 retaining ring connection between the side shaft journal 91 and the side
 shaft bevel gear 25. On the outside of the union nut 98, there is
 positioned a protective cover 46 for protecting the composite seal 30.
 In FIG. 5, the side shaft journal 111 is provided in the form of a hollow
 shaft which, in one step, changes from a portion with a greater diameter
 positioned outside the housing 11 to a portion with a smaller diameter
 inserted into the side shaft bevel gear 25. At the outer end, there is
 provided an inner shaft toothing 112 comprising an annular groove 113
 which is engaged by a retaining ring 114. Into the outer end, there is
 slid the outer joint part 121 by means of a cylindrical projection 122
 comprising an outer shaft toothing 116 which is also provided with an
 annular groove 117. The latter is also engaged by the retaining ring 114
 and thus axially secures the outer joint part 121 relative to the side
 shaft journal 111 in both directions.
 For the purpose of releasing the connection, a wedge-shaped tool can be
 slid into the annular gap 120 between a base part 123 of the outer joint
 part 121 and an end face 115 of the side shaft journal 111. In this way,
 the retaining ring connection can be released without applying any axial
 forces to the retaining ring connection between the side shaft journal 111
 and the side shaft bevel gear 25. On the outside of the side shaft journal
 111 there are positioned two protective covers 44, 45 for protecting the
 composite seal 30.
 In all embodiments, the side shaft journal in the form of a hollow shaft,
 inside, in the region of its side shaft bevel gear 25, is sealed by a
 cover 21 made of plastics. As a result, the connection between the outer
 joint part 41, 61, . . . and the side shaft journal 31, 51 can be
 separated without any oil being able to emerge, i.e. in particular,
 without having to empty the drive, and vice versa, the CV-jointed shafts
 can be mounted with the differential drive already fitted in the vehicle
 and completely filled with oil.