FR2504220A2 - HOMOCINETIC JOINT EQUIPPED WITH AN IMPROVED CENTER - Google Patents

Abstract

THE INVENTION CONCERNS A HOMOKINETIC JOINT EQUIPPED WITH AN IMPROVED CENTER. LEDIT JOINT INCLUDES A CENTERER 136 PRESENTING A CIRCULAR RIB 146, THE INTERMEDIATE PART OF WHICH IS THICKER THAN ITS INTERNAL AND EXTERNAL PARTS AND A CIRCULAR THROAT 150 WHOSE INTERMEDIATE PART IS THINER THAN ITS INTERNAL AND EXTERNAL PARTS, THE ADITE RIB AND THE LADITE TEETH LOCATED ON AN AXIS COINCIDING WITH THE ROTATION AXIS OF A FIRST FORK, AND ANOTHER CIRCULAR RIB 152, THE INTERMEDIATE PART OF WHICH IS THICKER THAN ITS INTERNAL AND EXTERNAL PARTS AND ANOTHER THROAT 156, OF WHICH THE INTERMEDIATE PART IS LARGER THIN THAN ITS INTERNAL AND EXTERNAL PARTS, BOTH ARE LOCATED ON AN AXIS OF SYMMETRY COINCIDING WITH THE AXIS OF ROTATION OF A SECOND FORK. APPLICATION TO HOMOCINETIC JOINTS.

Description

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  The present addition relates to a homogeneous seal

  kinetics with an improved centering device.

  Homokinetic joints are well known in practice and have the advantage of ensuring a constant ratio between the rotational speeds of the driving and driven shafts that they couple.

  first extreme fork connected to a leading and

  carrying two prongs in which are journalled two opposite trunnions of a first spider A second

  fork is connected to a driven shaft and has two

  in which there are two opposite journals of a second journal A clevis connects the two extreme forks and has arms in which the opposite journals of the two forks are journalled, the latter journals being perpendicular to those journalling

  in the forks of the extreme forks.

  To ensure a constant relationship between the

  rotation of the leading and driven shafts, it is essential

  so that, when they are not in the extension of one another, their respective axes of rotation make two equal angles with that of the connecting clevis. For this purpose, this last clevis contains a centraliser situated between

  the two extreme forks so far, such a cen-

  treur generally has the shape of a ball joint with one of the extreme forks supports the female element or bowl and the other extreme fork supports the male element or ball joint To really ensure the consistency of the ratio between the rotation speeds of the two shafts, the ball joint and its bowl must come into contact at a point equidistant from the trunnions which, held by the arms or wings of the clevis

  link, are part of the two braces mentioned above.

  The centering components currently used

  must be separated from one another when the leading and driven trees are no longer in line

  from each other and so make an angle one-to-the-other.

  The greater this angle, the more these components deviate from each other If the centering device is a joint

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  patella, the ball moves relative to its bowl so that they are no longer in contact at a point equidistant from the axes of the aforementioned journals. As a result, the angles of movement of the driving and driven shafts are no longer exactly identical and consequently , the constant and precise relationship between tree speeds

leading and led is no longer insured.

  The present addition relates to a homogeneous seal

  kinetic equipped with a centraliser whose elements are

  always in contact at equidistant distance from the axes of the

  Thus, an extreme fork has first ribs or teeth facing the other end fork, the axis of symmetry of the teeth coinciding with the axis of rotation of the fork.

  said extreme fork and shaft leading or driven to

  which is subject to it Similarly, the other fork ex-

  treme has second ribs or teeth making

  facing the fork mentioned first, the axis of symmetry

  sort of these teeth coinciding with the axis of rotation of the other fork and the shaft leading or led to which it

  is subject The sets of teeth are offset by one half

  tooth, regardless of the position of the extreme forks and shafts leading and led The teeth are also

  disposed in curvilinear or segment configurations

  spherical centers whose centers are located at

  section of the axes of the trunnions of the two braces.

  Thus, a longitudinal section passing through the center of the teeth therefore has a configuration corresponding to that of a toothed wheel segment The teeth have a profile or a

  configuration such as the actual points of contact

  they are on the primitive circles,

  tersection with a line passing through the centers of

  such a profile is generally developed.

  pante or of a similar configuration.

  figuration of the teeth is preferably such that their intermediate parts are thicker than the parts

  extreme when viewed in cross-section.

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  Also, a central tooth of one fork is thicker than an adjacent circular tooth, when viewed in cross section, and a central recess of the other fork is wider than a circular groove, sectional view. transverse, located between the adjacent circular teeth. The new centraliser not only ensures a constant ratio between the driving and driving shaft speeds, but also a better rolling contact and less sliding contact, which ensures a less

  great loss of friction and probably less wear.

  The centralizer also makes it possible to bring the forks closer to the constant velocity joint, which makes it possible to obtain a larger-angle. In addition, the new centering device does not have any

moving parts.

  Accordingly, the present addition

  object a homokinetic joint equipped with a perfect centering device

  This constant velocity joint ensures a consistent

  so much more precise between the speeds of the trees leading and

  led that are connected by the joint.

  The addition also relates to a homokinetic joint equipped with a centraliser which comprises circular teeth whose intermediate parts are thicker than their two extreme parts, and circular grooves whose intermediate parts are narrower than their two extreme parts, when seen in cross section A centering element has a circular tooth and a central tooth which is thicker than the circular tooth and another centering member has a circular groove and a central recess which is wider than the latter when viewed in cross-section, said centering device assures

  less loss of friction and less wear.

  The addition will be described in more detail with reference to the accompanying drawing by way of non-limiting example and in which:

  FIG. 1 is a fragmen-

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  on a large scale of the centroid of the homokinetic joint according to the present addition: and FIG. 2 schematically represents two

  centering teeth of Figure 1 in several positions.

  The centering device according to the present addition is

  136 in Figure 1 The biggest difference between

  said centering device and the centraliser 86 described in the patent

  The main problem lies in the configuration of the teeth or

  in the difference between the dimensions, in the ob-

  serving in section, the central tooth and the recess

  central compared to the teeth and circular grooves.

  An element 138 of the centraliser can be realized in the work

  88, but is preferably replaceable. In this case, the centering element may comprise a rod 140 which can be force-fitted into a bore of the cross-member 88 or which can be threaded, as shown, and screwed into the

  tapped hole 96 of the cross member 88 A member 142 of the center

  In this case, the element 142 may comprise a rod 144 which can be press-fitted in a bore of the cross-member 90 or which can be threaded, as shown, and screwed into the tapped hole 102 of the crossbeam 90 The threaded rods 144 and 144 can also pass through the orifices 96 and 102 and can be secured by nuts behind the cross members 88 and 90 As also applies to the elements 92 and 98 of the centraliser, the elements 138 and 142 can then be removed and replaced without it being necessary to replace the whole of the constant velocity joint 10. The element 142 of the centraliser has a rib or circular tooth 146 and in the center of this last a thicker tooth 148, said teeth being separated by

  a circular groove 150 The element 138 of the centering device

  carries a rib or circular tooth 152 surrounded by a tooth or external circular ring S 54 Circular circle 155 is formed between teeth 152 and 154 and a recess

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  central 158 is hollowed out in the circular tooth 152 to

accommodate the central tooth 148.

  The teeth 146, 148, 152 and 154 are positioned on a spherical segment so that the centers are at the points where the axes of the trunnions of the crossbars intersect, as in the case of the teeth 104, 106, 114, 116 and 118 of the embodiment of the main patent. The teeth of the elements 138 and 142 are offset by half a tooth so that they can mesh with one another.

  generally similar to the classic

  However, the teeth have profiles that are very different from those of conventional gear teeth

  circular 146 and 152 as well as the central tooth 148

  all of them have intermediate parts which are thicker than their inner and outer extremities respectively corresponding to the root and the top of the teeth. The internal parts of the teeth are also off-set with respect to the intermediate parts. Similarly, the intermediate parts of the circular grooves and the recess 158 are narrower than the

  bottoms and the upper parts of throats and

  When the external parts of teeth 146, 148

  and 152 are of involute or epicyclic configuration

  dale, the base circle from which the profile is

  has a radius that is smaller than that of the circle

  of a quantity between 0 and 1/4 of the

  tooth, the teeth being cut off from the circle of

  base to the foot circle The detachment of the circular teeth

  can be important without unduly weakening the teeth, thanks to their circular or annular configuration With

  this configuration, the internal surfaces of the teeth

  killed between the base and foot circles do not usually

  not in contact with other teeth, at least to a significant extent The internal parts of the teeth that are off-set form mainly connecting protuberances which protrude outwards beyond the

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  outer portions of said teeth so that the base circle is away from the foot circle to the outside and is

  located on or near the original circle.

  Particular configurations of the teeth, grooves and recess have the advantage of allowing the center 136 to function satisfactorily, even when relatively large tolerances of other components of the constant velocity joint vary the spacing.

  between the elements 138 and 142 of the centraliser Thus, the space

  the size of the cuvettes varies in the

  in the concentricity or eccentricity of

  lons and in the cuvettes themselves as well as in

  the spacing of the bowls of reach of the extreme forks.

  A variation in the spacing of the posterior base of the centrator elements relative to the original circle of

  teeth can also occur Naturally, tolerances

  rances may be cumulative or may be offset.

  However, with the particular shape of the teeth, grooves and obviously used, such tolerances are acceptable even if they are cumulative When the teeth have a profile or conventional involute configuration in cross section, as seen in FIG. 4 of the main patent, individual shims may be required between the connecting elements and the centering elements to compensate for variations in spacing. This requires additional elements and

  especially extra work.

  The involute configuration of the upper parts

  of the teeth allows the centraliser 136 to function satisfactorily in the presence of greater tolerances of the mounting dimensions, but results in a certain deviation from the constant ratio between the speeds of the shafts. The epicycloidal shape of the upper parts of the teeth provides a consistent and accurate ratio between speeds, but with smaller tolerances for dimensional variations It is possible to use tooth profiles approaching the configuration

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  or epicyclic configuration as well as the profiles that are between them Such profiles of the upper part of the teeth above

  of the basic circle, being in an intermediate part

  1 teeth are designated herein

  by conventional gear tooth profiles.

  2, the centering device and more particularly its elements 138 and 142 are engaged and the teeth are spaced so that the base circles of the elements of the centering device touch each other.

  on the axis passing through the centers of these two elements.

  The base of a tooth touches the base of the opposite tooth on

  the base circle when they are on the axis

  When the centering elements are misaligned with respect to this axis in one direction, the base of the first tooth slides along the outer surface of the second tooth beyond the base circle until the head is reached. at a point where the separation of the teeth occurs. This point is where the head circle of the first centering element and the base circle of the other element intersect, starting from the axis passing through. centers, if the centering elements are misaligned with respect to this axis in the opposite direction, the base of the second tooth slides along the outer surface of the first tooth beyond the base circle until the However, it should be noted that there is essentially no

  sliding between the surfaces of the teeth during the

  normal joints, but only when

  that the angles are changing In reality, there is a cer-

  some tooth deflection with some sliding contact

  but the latter is relatively low, particularly

  bind when compared with a ball-type centering device that has a large slip contact

  when rotating the universal joint.

  With the classic gear teeth developing

  pante, the contact line is tangent to both circles

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  However, with the profile of the teeth of Figure 1, the pressure line is closer to a line perpendicular to a line passing through the centers of the gears, the pressure angle approaching zero and corresponding only at about half of the pressure angle of the conventional tooth pressure line having an involute profile This smaller pressure angle

  in particular allows the centering elements of the

  to operate in a satisfactory manner with

  greater tolerances in the homokinetic joint.

  As seen in FIG. 2, the pressure angle of the pressure line is small, said pressure line passing between the point where the base circle of one of the centering elements intersects the leading circle of the second element and o the base circle of this second element of the centerer crosses the head circle of the element first mentioned In reality, in this case, the pressure line is not really a straight line but instead follows the circle base of one side of the axis of symmetry passing through the centers of the elements of the centraliser, then follows the other base circle on the other side of said axis of symmetry, which gives this line an S configuration of low amplitude. With centrers having teeth having a conventional involute profile, when the joints are articulated at large angles, for example 45, the

  flanks of the teeth quickly separate from the

  tact around the circular shape of the teeth.

  larger tooth gaps are needed to resist transverse forces tending to misalign

  the centering elements and may result in a long

  However, when the teeth present the profile according to the invention with an external part generally having the conventional profile of a gear tooth and with the relief, a closer cooperation is obtained.

  gear teeth, the surfaces of the teeth having

  dance to separate less quickly when the joints are

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  articulated at greater angles.

  quence, a smaller gap may still be

  allow them to withstand the transverse forces

  misalignment of centering elements This smaller tooth gap increases longevity. The points of contact between the teeth of the centraliser elements are normally in the common plane defined by the two axes of the trees and tend to

  rather than oppose the forces acting

  in particular to this common plane Forces acting at angles below a right angle are the cause

  partial resistance and partial slip

  in the direction in which they exercise

  the centreur'and more particularly their teeth

  can deviate slightly to resist these forces.

  thus forcing the flanks of contact to move away from the common plane The particular conformation of the teeth allows the centering element to resist more effectively the forces tending to misalign the two shafts, in particular

  when the forces are exerted from angles

  port to the plane defined by the axes of the two trees.

  In fact, it has also been shown that

  particular threads of teeth, throats and recess

  make it easier to achieve the elements of the cen-

  than the tooth profiles of the centering elements

  shown in Figure 4 of the main patent for example.

  Teeth, grooves and recess can be realized

  on the elements of the centraliser both of the form of reaction

  of Figure 4 of the main patent and that of

  shown in Figure 1 of this application in use.

  reading strawberries with racks configuration.

  Each rack is rotated around its circle

  primitive along the original circle of the element of the cen-

  With the teeth of elements 138 and 142 of the centraliser shown in Figure 1 of this specification, the teeth

  of the rack have flanks that are perpendicular to

  to the original circle of the said rack, the

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  underside of the pitch circle The top surfaces

  of the pitch circle to the upper surface of the teeth may be inclined by 15

lower, for illustrative purposes.

  The centralizer 136 is preferably provided with a lubricating sheath 160. The latter has two shims 162 and 164 which are held by the elements 138 and 142 of the centraliser. For this purpose, the first element 138 has an extreme groove or a recessed portion 166 and an adjacent retaining plate 168 interposed between the centering member 138 and the cross member 88. The retaining plate has a peripheral flange 170 which is concentric with the member 138 and cooperates with the groove 166 to retain the edge 162. Also, the centering member 142 has an annular or recess groove 172 and an adjacent retaining plate 174 between the member 142 and the cross member 90. The retaining plate 174 also has a peripheral flange 176.

  to retain the bank 164 of the sheath 160.

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Claims (8)

  1 Homokinetic joint for coupling two shafts each having an extreme fork, characterized in   it comprises a centralizer (136) having a first   a first circular rib (146) and a first circular groove (150) formed on a first connecting beam (90) supported by a first fork, the rib (146) and the groove (150) being located on an axis of symmetry coinciding with the axis of rotation of the first fork,   said first rib (146) having an internal portion   median-thicker than its inner and outer end portions in cross-section, said first groove (150) having an intermediate portion thinner than its inner and outer end portions in cross-section, and a   second circular rib (152) and a second circumferential groove   eyelet (156) formed on a second connecting beam (88) supported by a second end fork, the second rib (152) and the second groove (156) being located on an axis of symmetry coinciding with the axis of rotation of the second fork, said second rib (152) having an intermediate portion thicker than its inner and outer end portions in cross-section, and said second groove (156) having an intermediate portion thinner than   its inner and outer extremities in transverse section dirty.   2 seal according to claim 1, characterized in that the outer portions of said ribs (146, 152)   have generally involute profiles.   3 Joint according to claim 2, characterized in that the internal parts of said ribs (146, 152) are misaligned.   4 seal according to claim 1, characterized in that it comprises a central tooth (148) on the first   crossbar (90) which is thicker than the first   first circular rib (146) in cross-section, and a central recess (158) on the second connecting web (88) which is wider than the second groove (156) 2504,220   of the second cross member (88) in cross section.   Joint according to claim 4, characterized in that said central tooth (148) has an intermediate portion which is thicker than its inner and outer end portions in cross-section and in that said recess (158) has a thinner intermediate portion than its internal and external extremities in cross-section. 6 seal according to claim 1, characterized   in that the first circular rib (146) and the first   first circular groove (150) are formed on a first   element (142) of the centraliser which is mounted   on the first connecting beam (90) and in that the second circular rib (152) and the second circular groove (156) are formed on a second centering element (138) which is removably mounted on the second connecting beam (88).   Joint according to claim 6, characterized in that the elements (138, 142) of the centraliser have threaded rods (140, 144 ') which are screwed into threaded bores (96, 102) of the respective crosspieces (88, 90). so as to be removably mounted on these last ones.   8 seal according to claim 6, characterized in that the elements (138, 142) of the centraliser present   circular grooves (166, 172) near the crossings   its respective l 88, 90) and a sheath (160) which have integral edges (162, 164) housed in the grooves   (166, 172) last cited.   9 Seal according to claim 8, characterized in that it comprises a plate (168, 174) having a flange   circular (170, 176) and inserted between each of the   the centrers and the respective cross-member (88, 90), the circular flanges (170, 176) of said plates (168, 174) being in proximity to the last-mentioned grooves (166, 172) to assist hold in place shores (162, 164) of the sheath.