CV-jointed shaft with two fixed joints and seperate sliding means

The invention relates to a CV-jointed shaft with a first and a second constant velocity fixed joint 1, 1' and an intermediate shaft 14. The intermediate shaft 14 comprises a plunging sleeve 22 in which there is received a plunging journal 15 by means of balls. The plunging journal 15 and the intermediate shaft 14 are each provided with a plug-in portion 16, 25 which are identical in shape and are received in receiving bores 7 of the inner parts 5 of the two constant velocity fixed joints 1, 1'. By using this design it is possible to provide a CV-jointed shaft wherein, to a considerable extent, the constant velocity fixed joints 1, 1' can be assembled of identical components.

BACKGROUND OF THE INVENTION
 The invention relates to a CV-jointed shaft having a first and a second
 constant velocity fixed joint. Each joint comprises an outer part with
 outer running grooves, an inner part with inner running grooves and a cage
 arranged therebetween for guiding balls which engage opposed outer running
 grooves and inner running grooves, forming a pair. The outer part is
 provided with first connecting means and the inner part is provided with
 second connecting means, having a plunging assembly which comprises a
 plunging journal connected to the inner part of the first constant
 velocity joint and a plunging sleeve connected to an intermediate shaft.
 Rolling contact members engage opposing running grooves arranged in the
 plunging journal and the plunging sleeve, and the intermediate shaft is
 connected to the inner part of the second constant velocity fixed joint.
 Such a CV-jointed shaft is described in U.S. Pat. No. 5,611,733. The
 plunging journal is produced to be integral with the inner part of the
 first constant velocity fixed joint, with a journal being formed on to the
 inner part of the second constant velocity fixed joint. The intermediate
 shaft, by means of a first portion, is firmly positioned on the journal of
 the inner part of the second constant velocity fixed joint. At its other
 end, the intermediate shaft carries the plunging sleeve. The disadvantage
 of this embodiment is that the inner parts of the two constant velocity
 joints have to be of a different design. This results in higher costs,
 especially for the tools for producing the inner parts.
 It is the object of the invention to propose a CV-jointed shaft which can
 be produced at reasonable cost.
 SUMMARY OF THE INVENTION
 In accordance with the invention, the objective is achieved in that the
 inner parts of both constant velocity joints comprise identical receiving
 bores, that the intermediate shaft, at its end removed from the plunging
 sleeve, and the plunging journal, at its end projecting from the plunging
 sleeve, are each provided with an plug-in portion, which two portions are
 designed to match the two receiving bores.
 The advantage of this embodiment is that, with the exception of the
 connecting means for the outer parts, identically designed CV fixed joints
 can be used for the CV-jointed shaft. The resulting advantage consists in
 that the degree of deformation for the inner parts as compared to prior
 art inner parts can be greatly reduced, because as a rule it is possible
 to use inner parts produced by non-chip forming methods in order to keep
 costs at a reasonable level and to achieve a high degree of repeat
 accuracy. The intermediate shaft is preferably provided in the form of a
 tubular shaft and comprises the plunging sleeve. For the plug-in portion
 there is selected a wall which is thicker than the wall portion in the
 region between the plug-in portion and the portion designed as a plunging
 sleeve. Such an intermediate shaft, starting from a tube, can be given its
 final shape by hammering, for example.
 Furthermore, the plunging journal is also tubular in order to keep the
 deformation forces as low as possible. The plunging journal with the
 running grooves and the teeth in the region of the plug-in portion can
 also be produced by hammering. To achieve a rotationally fast connection
 between the inner parts and the plug-in portions of the plunging journal
 and the intermediate shaft respectively, these parts and portions
 respectively are provided with teeth which extend parallel relative to the
 longitudinal axis of the inner parts.
 A particularly advantageous embodiment of the CV-jointed shaft is achieved
 if the outer parts of the constant velocity fixed joints are each
 associated with a supporting element with a hollow spherical face
 comprising a supporting face which serves to support a spherical control
 face of a dish-shaped control element. The edge of said dish-shaped
 control element comprises a planar end face on which the inner part is
 supported by means of a planar end face. The longitudinal axis of the
 inner part is positioned perpendicularly on the latter planar end face.
 The inner part is held and centered relative to the outer part by balls
 which are guided in a cage. The cage, by means of a hollow spherical face,
 is supported on a spherical outer face of the inner part. There is no
 contact between the cage and the outer part. As, in the aligned condition,
 the inner running grooves and the outer running grooves, from the CV fixed
 joint end with which the supporting element is associated, comprise a
 narrowing cross-section along the longitudinal axis, the inner part is
 centered relative to the outer part along the longitudinal axis on the
 joint articulation center by the control element. By designing and
 arranging the control element in this way, it is possible to select a
 relatively large diameter for the receiving bore. It only has to be
 ensured that underneath the inner running grooves there is sufficient
 material in the radial direction to permit the transmission of torque. One
 type of constant velocity fixed joint which will particularly benefit from
 this invention is claimed and described in greater detail in the U.S.
 patent application Ser. No. 09/193,097.

DETAILED DESCRIPTION
 The inventive CV-jointed shaft consists of two constant velocity fixed
 joints 1, 1' and one intermediate shaft 14 with a plunging assembly. The
 CV-jointed shaft as illustrated serves to drive the rear wheels of a motor
 vehicle, for example, with the constant velocity fixed joint 1, by
 connecting means to be described below, being connected to the rear wheel
 differential of the vehicle, and with the constant velocity fixed joint
 1', by means of further connecting means yet to be described, being
 connected to the wheel hub of the rear wheel of the motor vehicle. The two
 CV fixed joints 1, 1' are substantially of identical design. To the extent
 that this is significant for the present invention, the differently
 designed components will also be described in greater detail below. To
 provide a clearer overview, the reference numbers of the individual
 components are sometimes associated with the one and sometimes with the
 other CV fixed joint 1, 1'. The two constant velocity fixed joints 1, 1'
 each comprise an outer part 2 which is provided in the form of a plate
 metal part, i.e. it is thin-walled. The latter, in its inner face, is
 provided with a plurality of outer running grooves 3 which are
 circumferentially distributed around the longitudinal axis of the outer
 part 2, which extend in meridian planes and which, starting from the
 opening end associated with the flange 4 and the connecting journal
 respectively, constituting the connecting means, extend in an
 undercut-free way. This means that, in the direction away from the flange
 4, the track base of the outer running grooves 3 approaches the
 longitudinal axis of the outer part 2. By providing the outer part 2 in
 the form of a plate metal part, the wall of same, in a cross-sectional
 view, comprises bulges in which the outer running grooves 3 are arranged.
 In the cavity of each outer part 2, there is accommodated an inner part 5.
 The inner part 5 is provided with inner running grooves 6 which are
 arranged in the outer face of same so as to be circumferentially
 distributed in accordance with the outer running grooves 3. The inner
 running grooves 6 comprise a track base which extends away from the flange
 4 and the connecting journal respectively, and from the longitudinal axis
 of the inner part. The inner part 5, at its outer face portion removed
 from the flange 4, comprises a spherical face on which there is supported
 a cage 8 by means of its hollow spherical face. The cage 8 is provided
 with windows which are circumferentially distributed in accordance with
 the pairs of outer running grooves 3 and inner running grooves 6 and in
 each there is received a ball 9 which projects radially outwardly and
 inwardly from the windows beyond the cage 8 and, for torque transmitting
 purposes, engages the outer running grooves 3 and inner running grooves 6
 respectively. Because of the above-described course taken by the outer
 running grooves 3 and inner running grooves 6, the balls 9, during the
 transmission of torque towards the flange 4 and connecting journal
 respectively, apply a force to the cage 8, which force holds the cage 8 in
 contact with the inner part 5. There is no contact between the outer face
 of the cage 8 and the inner face of the outer part 2. The inner part 6 is
 centered relative to the outer part 2 along the longitudinal axis of the
 outer part 2 away from the flange 4 and connecting journal respectively,
 and also in the radial direction, by the balls 9. Furthermore, each inner
 part 5 comprises a toothed receiving bore 7, with the teeth being pointed
 and extending parallel to the longitudinal axis of the inner part 5.
 Towards the flange 4 and connecting journal respectively, the inner part 5
 with the cage 8 and the balls 9 is held in the outer part 2 by a control
 element 10 which is dish-shaped and whose edge is provided with an end
 face on which the inner part 5 is supported by an end face. Furthermore,
 the control element 10 comprises a spherical control face 11 which rests
 against a supporting face 13 of a supporting element 12 and a supporting
 disc 28 which is provided in the form of a hollow sphere. The ball radii
 of the control face 11 and of the control face 13 are centered on the
 joint articulation center 0. The supporting element 12 for the constant
 velocity fixed joint 1 is provided with a flange portion by means of which
 it is fixed, for example by riveting, to the flange 4 of the outer part 2.
 In this way, the inner part 5 is centered relative to the outer part 2 on
 the joint articulation center. In the case of the constant velocity fixed
 joint 1', the supporting element 12' holds the supporting disc 28.
 The second constant velocity fixed joint 1', however, differs from the
 first constant velocity fixed joint 1 as far as the outer part 2 is
 concerned. The outer part 2 comprises a receiving portion for the outer
 circumference of the supporting element 12', so that the latter, which is
 a solid part, can be connected in a rotationally fast way to the outer
 part 2 by means of a cross-section which deviates from the circular
 cross-section. Furthermore, the supporting element 12' comprises the
 connecting journal which serves to connect the second constant velocity
 fixed joint 1' to the wheel hub of a motor vehicle for example, whereas
 the flange 4 of the first constant velocity fixed joint 1 serves to be
 connected to an output flange of one of the output bevel gears of a
 differential. The two constant velocity fixed joints 1, 1' are connected
 to one another by an intermediate shaft 14 with a plunging assembly which
 permits a change in the distance between the joint articulation centers of
 the two CV fixed joints 1, 1'. The plunging assembly comprises a plunging
 journal 15 which is tubular and comprises a bore 19. Furthermore, it
 comprises a plug-in portion 16 whose outside is provided with a set of
 teeth 17 which is designed to match the receiving bores 7 of the two CV
 fixed joints 1, 1'. The plunging journal 15 is secured in one of the two
 plug-in bores 7 by means of a securing ring 18. Furthermore, the plunging
 journal 15, comprises running grooves 20 in its outer face, which extend
 parallel to the longitudinal axis of the inner part 5 and in which the
 rolling contact members in the form of balls are able to roll. The latter
 are guided by a cage for example. The plunging journal 15 is inserted into
 a plunging sleeve 22 which is associated with the intermediate shaft 14,
 i.e. it is produced so as to be integral therewith. Plunging sleeve 22, is
 provided with running grooves 23 in its inner face, which are
 circumferentially distributed in accordance with the running grooves 20
 and which are engaged by the balls 21. This assembly permits the
 transmission of torque between the plunging journal 15 and the
 intermediate shaft 14, as well as a displacement of the plunging sleeve 22
 and of the plunging journal 25 towards the longitudinal axis relative to
 one another. The assembly is sealed by a convoluted boot 24 which, by
 means of its large diameter, is secured on the outer circumference of the
 outer part 2 of the CV fixed joint 1 and by means of its small diameter on
 the outer face of the plunging sleeve 22. Following the plunging sleeve
 22, the intermediate shaft 14 comprises a central portion 26 which,
 towards the other end, changes into a plug-in portion 25 which comprises a
 thicker wall than the central portion 26 and, on its outer face, is
 provided with a set of teeth 27 which corresponds to the set of teeth 17
 of the plunging journal 15 and is inserted into the receiving bore 7 of
 the inner part 5 of the second CV fixed joint 1' and secured therein by a
 securing ring 18. For sealing the CV fixed joint 1', there is provided a
 further convoluted boot 24' which, by means of its large diameter, is
 secured on the outer face of the outer part 2 of the second CV fixed joint
 1' and, by means of its small diameter, on the outer face of the
 intermediate shaft 14.
 Although a preferred embodiment of this invention has been disclosed, a
 worker of ordinary skill in the art would recognize that modifications
 come within the scope of this invention. For that reason the following
 claims should be studied to determine the true scope and content.