FR2722849A1 - UNIVERSAL HOMOCINETIC JOINT - Google Patents

Abstract

Universal sliding-type constant velocity joint which prevents the increase of the pushing force. A guide block (11) is supported on each pin so that it can slide relative to the axis of the pin and so that the pin can pivot relative to the guide block. A ball circulation groove (12) is formed in each side of the guide block and it comprises two rectilinear paths, namely a loaded path (12a) and an unloaded path (12b), and two curved paths which connect the straight paths to each other. The path without load and the curved paths have a greater groove depth than the radius of the balls (13). Each guide groove provided in the outer ring (1) has a flat surface (14) opposite the unloaded path (12b). A space larger than the diameter of the ball (13) is defined between each flat surface and the unloaded path, so that the balls cannot get caught between the guide groove and the guide block during their movement towards the path without load via curved paths.

Description

UNIVERSAL HOMOCINETIC JOINT

  The present invention relates to a universal joint

  sliding type homokinetic salt, mainly intended for use in an automobile.

  A universal tripod constant velocity joint is re-

  presentation of a sliding constant velocity universal joint. Common tripod constant velocity universal joints have a serious drawback. More precisely,

  during the transmission of a torque by the tri-shaft

  pode, which is mounted in the outer ring, when this

  tree forms a certain working angle with the tree of the year

  outer ring, the spherical surface rollers supported on the tripod journals incline relative to the guide grooves provided in the outer ring. By

  following, the rollers tilt and slide so while rolling

  lant relative to the guide grooves. If the rollers slide in the guide grooves, this results in an axial thrust which in turn generates vibrations and

heat generation.

  To try to solve this problem, the present applicant has proposed a universal constant velocity joint.

  tripod type as shown in Figures 7 to 10 (pu-

  Japanese patent not examined 5-94534). This seal includes an outer ring 20 in the inner periphery of which three guide grooves 21 are formed, while a tripod 22 housed in the outer ring has three pins 23. A spherical sleeve 24

  is slidably mounted on each pin 23.

  A guide block 25 is mounted on each spherical sleeve.

  that 24. A ball circulation groove 26 has a confi-

  elliptical guration comprising two rectilinear parts

  26a and 26b and curved parts 26c which connect the ex-

  hoppers of the straight parts to each other. Most

  27 balls are housed in the circulation groove.

  tion of balls 26. As shown in FIGS. 8 and 9, a rounded raceway 28 for guiding the balls 27 in the rectilinear part 26a is formed in each side wall of each guide groove 21, on the side of its diameter outside. On the inside of each guide 21 is formed a curved guide surface 29 to prevent the balls 27 from falling from the other part

straight 26b.

  In addition, the distance between the guide surface

  dage of balls 29 and the bottom of the rectilinear part 26b

  of the circulation groove 26 is larger than the diameter

  meter of the balls 27. Thus, the balls 27 which are in the rectilinear part 26b of the groove 26 are not

subject to a charge.

  When this universal constant velocity joint takes a certain working angle, the spherical sleeves 24 slide relative to the guide blocks 25, while

  the latter remain in fixed positions. So when

  the CV joint transmits a torque and takes a certain working angle, the guide blocks move along the guide grooves 21 without

  change in their attitude, while the balls 27 rou-

  slow and travel along the straight path 26a of the

  groove 26 and that they are guided by the road

  LEMENT 28. The sliding resistance is therefore very low.

  corn. However, with this universal constant velocity joint, the groove depth of the straight path 26b is more

  smaller than the radius of the balls 27. In addition, the path rec-

  line 26b and the ball guide surface 29 formed on one side of the guide groove 21 are configured

  so as to guide the balls 27 and prevent them from falling.

  If we consider a ball 27a which is being pushed

  placed outside the curved part 26c of the groove 26 for reve-

  nir to the rectilinear part 26b as shown in the figure

  gure 10, this ball can get caught between an edge 30 of the ball guide surface 29 and an edge 31 of the path

  rectilinear 26b (Figure 9) when the balls 27 push

  smells each other. If one of the balls gets stuck, the balls 27 can no longer circulate regularly in the groove

  26, which produces a great pushing force.

  An object of the present invention is to provide

  a universal constant velocity joint in which the balls can

  wind circulate regularly in the ball circulation groove, without getting caught between the inner surface of

  the guide groove and the guide block, even when

  that they return to the part of the throat not subject to

  load, and in which the increase in pushing force

may be limited.

  In accordance with the present invention,

  a universal constant velocity joint comprising a ring ex-

  in the inner peripheral surface of which

  three axial guide grooves are provided, a tri-

  pode comprising three pins and housed in the ring ex-

  and a guide block supported on each turret

  lon so that it can slide relative to the axis of the

  and to allow the pivoting of the journal relative to

  port to the guide block. Each guide block has on each side a groove for the circulation of balls, each

  of these grooves having an elliptical configuration and

  taking a straight path subject to the load and a

  min straight not subject to load, these two paths

  being parallel to the axis of the outer ring, and

  mins curves that connect the straight paths to each other. A plurality of balls are received in each ball circulation groove so as to be able to roll and circulate in said groove, each guide groove

  comprising, on each side, a bil-

  them to guide the balls as they move in the straight path of the circulation groove which is subjected to the load. The universal constant velocity joint according to the invention is characterized in that the depth

  of the path not subject to the load of each circulation groove

  lation of balls is greater than the radius of the balls, and in that the distance between the side wall surface of the guide groove and the bottom of the path not subject to

  the load is greater than the diameter of the balls.

  Preferably, the guide groove has

  a flat surface opposite the path not subject to the load.

  In addition, the path not subject to the load must preferably

  rence have a cross-section in the shape of a U

  nant a semi-circular part, of shape substantially com-

  of the contour of the balls, and two short parts

  straight lines extending tangentially from the two ex-

  semicircular hoppers.

  The depth of the path or part of the groove

  ge of circulation of balls not subjected to the load is larger than the radius of the balls. So even when

  balls which are in the path not subject to the load

  ge are in contact with the flat surface, they are safely guided by the path not subjected to the load. As a result, the balls cannot get caught between the block

  guide and the guide groove.

  In the following constant velocity joint

  the present invention, when transmitting a

  ple in a position such that the outer ring forms a working angle relative to the tripod, the guide blocks can move in the guide grooves without changing attitude, while the balls roll and

  circulate in the ball circulation grooves. The re-

  slip resistance therefore remains low so that the

  vibration and noise may be limited.

  The path of the ball circulation groove which is not subjected to the load has a depth greater than the radius of the balls. In addition, each guide groove has a flat surface opposite the path not subjected to the load. By creating a space, between this flat surface and the bottom of the path not subject to the load, which is greater than the diameter of the balls can be guided and circulate regularly in the groove, even if they come into contact with the flat surface for that they follow the path back to

the path not subject to the load.

  As a result, the uncharged balls never get caught between the guide groove and the block.

  guidance. The pushing force is therefore greatly reduced.

  It is not necessary to form a curved ball guide surface in the outer ring to prevent the balls from falling. The outer ring of the constant velocity universal joint according to the present invention

  is therefore simple in shape and can be easily manufactured

also by cold forging.

  Other aspects and objects of the present invention

  tion will appear on reading the description below,

  with reference to the accompanying drawings in which:

  Figure 1 is a front view with cross section

  end of the constant velocity universal joint conforming to a pre-

  mier embodiment of the present invention; Figure 2 is a section along the line II-II of Figure 1; Figure 3 is an enlarged view of part of Figure 2; Figure 4 is a front view of the groove for circulating balls of this seal; Figure 5 is a section of the seal, illustrating its operation;

  Figure 6 is a front view with cross section

  end of the constant velocity universal joint conforming to two

  xth embodiment of the present invention;

  Figure 7 is a front view with cross section

  ticale of a constant velocity universal joint according to the prior art;

  Figure 8 is a section along line VIII-

  VIII of Figure 7; Figure 9 is an enlarged sectional view of this seal; and FIG. 10 is a view of the seal illustrating the

  the way the beads flow through the throat.

  Preferred modes of reaction are now described.

  of the present invention, with reference to the figures

Figures 1 to 6.

  As shown in Figures 1 to 3, one year

  outer ring 1 has a closed end to which is fixed a first shaft 2. Three axial guide grooves 3 are formed in the inner periphery of the outer ring 1, at 120 degree intervals (Figure 2). As shown in Figure 5, a tripod 4 housed in the outer ring 1 is mounted on a second shaft 5 via a ridged surface 6, so as to rotate with the second shaft 5. Elastic snap rings 7 are fixed on the second shaft to prevent the axial movement of the tripod 4 along

tree 5.

  The tripod 4 comprises three pins 8 which each carry a sleeve or a spherical ring 9. Needles 10 are placed between each spherical sleeve 9

  and the pin 8, for rotatably supporting the man-

spherical chon 9.

  On each spherical sleeve 9 is mounted a guide block 11 having a cylindrical inner surface 11a which remains in contact with a spherical outer surface 9a of the sleeve 9 and which is guided by the latter. A ball circulation groove 12 is formed on each side

of each guide block 11.

  Figures 3 and 4 show in detail the

  ball circulation groove 12. This groove has a con-

  elliptical figuration and it includes two parts or

  mins rectilinear which are parallel to the axis of the outer ring 1, namely a path 12a subjected to the load and a path 12b not subjected to the load, and parts or curved paths 12c which connect the rectilinear paths one to the other. A plurality of balls 13 are placed so as to be able to roll in the circulation groove

balls 12.

  The path subjected to the load 12a has a curved cross section and its depth is not greater than the radius of the balls 13. On the other hand, the path not subjected to the load 12b and the curved connection path

  12c have a U-shaped cross section comprising a part

  semicircular tie A of shape substantially complementary to the cross section of the balls 11, and short rectilinear parts B which extend tangentially from the two ends of the semicircular part A. The depth of the groove at this location is greater

than the radius of the balls 13.

  Each of the guide grooves 3 has, on its two sides, planar surfaces 14 which are slightly inclined relative to the plane passing through the centers of

  the plurality of balls 13 placed in the circulation groove

  lation of balls 12, so as to define a space greater than the diameter of the balls 13 between the planar surface 14 and the path not subjected to the load 12b. On the other hand, a ball raceway 15 is formed at the angle

  o the flat surface 14 and the internal surface of the spoke

  guide strip 3 are connected, to guide the balls

  13 along the path subject to load 12a.

  The operation of the seal according to the invention will now be described. When the second tree 5 takes

  an inclined position at a working angle relative to

  8 port to the first shaft 2, as shown in the figure, the pins 8 and therefore the spherical sleeves 9 are inclined relative to the longitudinal direction of the guide grooves 3. 5 In this state, the guide blocks 11 are prevented - failed to pivot by the contact between the balls 13, which

  are found in each path subjected to the load 12a, and the ball bearing path 15. Thus, when the spherical sleeves 9 tilt, a slip occurs10 between the sleeves 9 and the respective guide blocks 11.

  When the CV joint inclined at a working angle transmits a torque, the journal

  lon 8 and the spherical sleeve 9 can pivot in the guide block 11 and relative to it. On the other hand, the guide blocks 11 move in the longitudinal direction of the guide grooves 3 while

  serving an unchanged attitude. When the guide blocks 11 move, the balls 13 which are in each path subjected to the load 12a roll along the path of

  bearing 15 and run along the groove for circulating balls 12.

  The non-load path 12b and the curved connecting path 12c of the ball circulation groove 12 have a U-shaped cross section com-25 taking a semicircular part A and short straight parts B which extend tangentially from the two

  ends of the semicircular part A, and the depth of these paths is greater than the radius of the balls 13. Thus, even if the balls 13 are pushed by the other balls and come into punctual contact with the surface plane 14 as shown in phantom in the figure

  gure 3, as they move from the path subjected to the load 12a to the path not subjected to the load 12b via the connection path 12c, these balls 13 are also in point contact with one of the flat surfaces B of the path not subject to the load 12b. Thus, the balls never get caught between the guide groove 3 and the

  guide block 11. There is therefore no increase in

tion of the pushing force.

  FIG. 6 represents a second embodiment in which each guide block 11 has inclined surfaces 16 on its two sides, at its periphery

  outside. A ball circulation groove 12 is formed

  méée in each inclined surface 16.

  As in the first embodiment, the

  ball circulation groove 12 has an el configuration

  liptic including a straight path subject to the

  ge 12a and a straight path not subject to load 12b,

  and curved connecting paths 12c connecting the ends

  mites of paths 12a and 12b. The path not subjected to the load 12b and the curved paths 12c have the same shape

  than those of the first embodiment.

  In addition, planar surfaces 17 are formed at each end of each guide groove 3. Each planar surface 17 is slightly inclined relative to the plane passing through the centers of the plurality of balls 13 housed in the circulation groove of balls 12, so as to define a space larger than the diameter of the balls 13 between the path not subjected to the load 12b and

the flat surface 17.

  In the second embodiment, as in

  the first embodiment, the balls 13 are prevented

  to get caught between the inner surface of the spoke

  guide strip 3 and guide block 11.

  Although not shown, each guide block supported by the pins can present

  ter the ball circulation groove of Figure 2 and the ball circulation groove of Figure 6 in its outer diameter and inner diameter sides, respectively, so that the balls can circulate in each of the grooves.

Claims (3)

  1.- Universal constant velocity joint comprising a   outer ring (1) in the inner peripheral surface   re from which three axial guide grooves are formed   (3), a tripod (4) comprising three pins (8) and lo-   located in said outer ring, and a guide block (11)   supported on each said pin so that it can slide   ser relative to the axis of said pin and so that said pin can pivot relative to said guide block, each said guide block comprising a groove for the circulation of balls (12) in each of its sides,   each said ball circulation groove having a con   elliptical figuration and including a straight path   subject to load (12a) and a straight path not under-   loaded (12b), both parallel to the axis of the   said outer ring, and curved paths (12c) which   link said straight paths to each other, a greater   reality of balls (13) being received in each said ball circulation groove so that they can roll   and circulate in this groove, each so-called guide groove   dage (3) comprising, in each of its sides, a ball raceway (15) for guiding said balls   as they move in said straight path gene subject to the load,   characterized in that the depth of said path not under-   charged to (12b) each said circulation groove   of balls (12) is larger than the radius of the said bil-   them (13), and in that the distance between the surface of pa-   lateral king (14) of said guide groove and the bottom of said non-load path (12b) is larger   as the diameter of said balls (13).   2. Universal constant velocity joint according to claim 1, characterized in that said guide groove 11 (3) has a flat surface (14) opposite said   path not subject to load (12b).   3. Universal constant velocity joint according to claim 1 or 2, characterized in that said path not subjected to the load (12b) has a cross section in   U comprising a semicircular part (A), of sensitive shape   completely complementary to the contour of said balls (13),   and two short rectilinear parts (B) extending tangentially   tially from the two ends of said semicircular part.