FR2732084A1 - SLIDING TRANSMISSION JOINT, PARTICULARLY FOR MOTOR VEHICLE - Google Patents

Abstract

In this transmission joint, in particular with a tripod, one (3) of the two intermediate members interposed between the swivel journal (7) of each arm (6) and the associated guide path (8) is adapted to oscillate around a longitudinal axis (YY). The opposite guide path (9) is cylindrical, with a cross section centered on this axis (YY), and the second intermediate member (4) comprises a spherical inner surface cooperating with the journal (7) and an outer surface which, in cross section, is substantially conjugated with the second guide path (9), and which cooperates therewith.

Description

The present invention relates to a sliding transmission joint,

  of the type comprising: a male element intended to be fixed on a first shaft and comprising arms, each of which carries a swiveling journal which is integral therewith; a female element intended to be fixed on a second shaft and defining two guide paths situated respectively on the side and

  other of each pin; and intermediary bodies

  res interposed between each ball joint and the associated guide tracks, these intermediate members comprising a first intermediate member which cooperates

  with a first of the guide paths with a possibility

  oscillation unit around a directional oscillation axis

  tee longitudinally with respect to this guide path.

  The invention applies in particular to

  motor vehicle transmissions.

  The object of the invention is to provide a sliding transmission joint whose design, well adapted to the real conditions of use, allows satisfactorily, at a reduced cost, to be obtained during the

  almost the entire life of the performance seal

  these analogues to those of a conventional joint fitted with

  same first intermediate organs.

  To this end, the subject of the invention is a transmission joint of the aforementioned type, characterized in that the second guide path is cylindrical, with a cross section centered on said axis of oscillation, and in that the second intermediate member comprises a spherical inner surface substantially conjugate with the pin and cooperating with it, and an outer surface which, in cross section, is substantially conjugate with that of the second guide path, and which

cooperates with it.

  The transmission joint according to the invention may include one or more of the following characteristics: - the second intermediate member is an internally spherical and externally cylindrical shoe which slides on the second guide path; - The second intermediate member is an internally spherical and externally toroidal sector which rolls on the second guide path; - The first intermediate member comprises on the one hand a bar, in particular self-centering, which has on the side of the journal a spherical recess and on the opposite side at least one track with circular section, and, on the other hand, at least two balls which roll on this or these tracks and on the first guide path; - The first intermediate member is an internally spherical and externally cylindrical bar which slides on the first guide path; the first intermediate member is an internally spherical and externally toric sector which rolls on the first guide path; - The bar and the pad are rigidly connected to each other; - The bar and the shoe are secured to each other by at least one tenon-mortise assembly oriented towards said axis of oscillation; - The guide tracks have a rectilinear guideline parallel to the axis of the female element;

- the male element is a tripod.

  Examples of embodiments of the invention will now be described with reference to the appended drawing, in which: FIG. 1 schematically represents,

  partially in cross section, a trans-

  mission according to the invention; - Figure 2 is a partial view taken in section along the line II-II of Figure 1; - Figure 3 is a view similar to Figure 1, showing half of a variant of the transmission joint according to the invention; - Figure 4 is a partial view taken looking at arrow IV of Figure 3; and - Figure 5 is a view similar to the

  Figure 1, with cutaway, of another variant.

  The transmission joint shown in Figures 1 and 2 is intended to connect two shafts (not shown) which can slide relative to each other either in mutual alignment or at a breaking angle which can typically reach about 25. It essentially comprises a male or tripod element 1, a female or jaw element 2, three sets 3 with bars and

balls, and three pads 4.

  The tripod is made in one piece and includes a central hub 5, adapted to be secured to one of the two shafts, on which protrude

  radially three arms 6 angularly spaced 120.

  The radially outer part of each arm is

  shaped like a spherical journal 7 of radius r.

  The jaw 2 defines, for each arm 6, a pair of opposite raceways: a first raceway 8 constituted by a groove

  cylindrical with circular section, of which the direct line

  trice is rectilinear and parallel to the axis X-X of the jaw, and a second raceway 9 constituted by a cylindrical groove with circular section, of axis parallel to the same axis X-X. The radius R of the groove 9 is much greater than that r of the pin 7 and that

  r 'of throat 8, as will be described later.

  The assembly 3 consists of a self-centering bar 10 and two balls 11. The bar 10 internally has a spherical recess 12 substantially conjugate with the pin and cooperating with it, and externally two tracks 13 of circular section separated by a median projection 14. The tracks 13, in plan view, are in the extension of one another; in side view (Figure 2), they gradually move away from the path 8 from the projection 14. Each ball 11 is interposed between one of these tracks and the raceway 8, and the shape of the two tracks ensures a self-refocusing of the two balls, as described in FR-A-2 628 803 in the name of the Applicant. The set 3 is completed by a cage 15

retaining balls.

  The two balls 11 thus roll on the path 8, their centers moving along the axis Y-Y of this path 8. In each cross section of the jaw, the trace of this axis Y-Y is the center of the arc

  of circle which defines the opposite raceway 9.

  The radius R of the latter is therefore much greater than the radius

  r 'of path 8, and also to radius r of journal 7.

  The shoe 4 internally comprises a spherical recess 16 substantially conjugate with the pin 7 and cooperating therewith, and a cylindrical outer surface 17 substantially conjugate with the path of

  bearing 9 and cooperating therewith.

  In the embodiment described above, the line which joins the center of the tripod to that of the pin 7 is perpendicular to the line which joins the

  center of the balls 11 at said center of the journal.

  In service, the seal is mounted in a motor vehicle transmission so that, in forward gear, the engine torque is transmitted from the tripod to the jaw via the three assemblies 3. Under torque, a slight clearance appears on the side of the pads 4, so that the sliding resistance is practically that defined by the assemblies 3 and is therefore very low, even at an angle. In other words, in forward motion, that is to say for almost the entire operating time of the seal, the level of axial excitations transmitted by the seal

  to the vehicle structure is particularly weak.

  In reverse, it is the sliding resistance of the pads 4 which defines the sliding resistance of the joint. This resistance is greater than that corresponding to forward travel, but is

  acceptable given the very short duration of the function

  operation of the vehicle in reverse.

  In addition, thanks to the configuration of the raceways 8 and 9 and the intermediate members 3 and 4 for transmitting the torque, it is understood that when the

  joint is broken, which results in cross-section

  dirty, by a radial displacement, along their axis, of the arms 6, the oscillation of each assembly 3 around the axis YY is accompanied by that of the pad 4 associated around the same axis, so that no play due to these oscillations do not appear. We also note that the contacts between the various moving parts are either linear or surface, so that the contact pressures

remain moderate.

  To avoid, when operating in forward gear, any risk of inadvertent misalignment of the shoe 4, which could cause jamming when shifting into reverse gear, it may be desirable to connect

  to each other the bar 10 and the shoe 4.

  For this, we can make the bar and the shoe as a single piece. In the example of Figures 3 and 4, it is a solid part 18 provided with a spherical recess 19 which forms the surfaces 12 and 16 described above. To be able to introduce the pin into this recess, the latter is enlarged in the form of a buttonhole 20, while the pin is truncated in two planes 21, 22 parallel to each other and parallel to the axis of the arm 6; the two planes 21 and 22 are spaced from each other by a distance less than the width of the buttonhole. The trunnion is then introduced with the part 18 turned a quarter of a turn relative to its final position in FIG. 4, then, when the trunnion is in place, by rotating the same part 18 by one quarter turn

reverse.

  As a variant (FIG. 5), it is possible to connect the bar 10 and the shoe 4 only to the extent necessary to guarantee the oscillation of the latter around the axis YY of the path 8. As can be seen in the right part of Figure 5, where the arm 6 has been omitted, it is possible to provide the bar, at each end, with a lug 23 directed towards the shoe, and provide this shoe, at each end, with a mortise fork 24 directed to the

  bar and slidingly receiving the associated pin 23.

  The two tenons are contained in the plane P which passes through the axis Y-Y and which is perpendicular to

the axis of the arm 6.

  In this case, again, the pin 7 is preferably truncated as in Figures 3 and 4, this

  times to reduce the axial size of the joint.

  The invention can be applied to other sliding transmission joints of which one of the intermediate members associated with each arm can oscillate by

  in relation to its guide path 8. Such an intermingled organ

  diaire can be an internally spherical and externally toric sector, rolling on path 8, or even a simple internally spherical bar and

  externally cylindrical which slides on this path 8.

Claims (6)

CLAIMS i - Sliding transmission joint, of the type comprising: a male element (1) intended to be fixed on a first shaft and comprising arms (6) each of which carries a swiveling journal (7) which is integral therewith; a female element (2) intended to be fixed on a second shaft and defining two guide paths (8, 9) situated respectively on either side of each pin; and intermediate members (3, 4) interposed between each ball joint and the associated guide tracks, these intermediate members comprising a first intermediate member (3) which cooperates with a first (8) of the guide tracks with the possibility of oscillation around an axis (YY) of oscillation oriented longitudinally with respect to this guide path, characterized in that the second guide path (9) is cylindrical, with a cross section centered on said axis of oscillation ( YY), and in that the second intermediate member (4) comprises a spherical inner surface (16) substantially conjugated with the pin (7) and cooperating with it, and an outer surface (17) which, in cross section, is substantially combined with that of the second guide path (9), and which cooperates therewith.   2 - Transmission joint according to the claim   tion 1, characterized in that the second intermediate member   diaire (4) is an internally spherical and externally cylindrical shoe which slides on the second guide path (9).   3 - Transmission joint according to the claim   tion 1 or 2, characterized in that the second intermediate member is an internally spherical and externally toric sector which rolls on the second path guide (9).   4 - Transmission joint according to one   any one of claims 1 to 3, characterized in that   that the first intermediate member (3) comprises on the one hand a bar, in particular self-centering (10), which has on the side of the journal (7) a spherical recess (16) and on the opposite side at least one track (13) circular section, and, on the other hand, at least two balls (11) which roll on this or these tracks and on the first guide path (8). - Transmission joint according to one   any one of claims 1 to 3, characterized in that   that the first intermediate member is an internally spherical and externally cylindrical bar   which slides on the first guide path (8).   6 - Transmission joint according to one   any one of claims 1 to 3, characterized in that   that the first intermediate member is an internally spherical and externally toric sector followed   rolls on the first guide path (8).   7 - Transmission joint according to the claim   tion 4 or 5 when dependent on claim 2, characterized in that the bar (10) and the shoe (4)   are rigidly connected to each other.   8 - Transmission joint according to the claim   tion 4 or 5 when it depends on claim 2, characterized in that the bar (10) and the shoe (4) are secured to each other by at least one stud assembly (21) -mortaise (22 ) oriented towards said axis of oscillation (YY). 9 - Transmission joint according to one   any one of claims 1 to 8, characterized in that   that the guide tracks (8, 9) have a straight line   straight line parallel to the axis (X-X) of the element female (2). - Transmission joint according to one   any one of claims 1 to 9, characterized in that   that the male element (1) is a tripod.