FR2523673A1 - UNIVERSAL JOINT, CROSS FOR THIS SEAL, METHOD FOR MANUFACTURING THE SAME, AND METHOD FOR FINISHING A UNIVERSAL SEAL BEARING SURFACE - Google Patents

Abstract

THE INVENTION IS CONCERNED WITH LUBRICATING UNIVERSAL JOINTS. TO IMPROVE THE LUBRICATION BETWEEN A STUD 14 OF CROSS-BODY OF A UNIVERSAL JOINT AND A NEEDLE 24 OF BEARING MOUNTED BETWEEN THIS STUD AND A FORK OF A ROTATING ELEMENT, THE OUTER SURFACE OF THE STUD 14 IS MACHINED SO AS TO PRESENT DOORS 30 WHICH Alternate with grooves 32 so that there is always a film of lubricant 38 between the journal 14 and the needle 24 during the oscillation or vibration movements occurring between these two elements. FIELD OF APPLICATION: UNIVERSAL CARDAN TYPE JOINTS.

Description

The invention relates to cardan-type universal joints which, like this

  are known, include braces with cylindrical journals projecting radially and intended to be connected to forks protruding pairs of rotating elements. The invention relates more particularly to a device

  improved lubrication of the trunnion interface

  fork, as well as a method of manufacturing this arrangement.

  operative part. The journals of such seals are usually mounted in needle bearings which are themselves

  mounted in cup-shaped support rings

  In each ring there is a ring of such support needles, physically interposed between the inner circumferential surface of the ring and an associated trunnion so that virtually frictionless movement can take place.

  between the journal and the bearing ring.

  Anterior trunnions are ground to high degrees of finishing and polishing to establish

  rolling contact with needle bearings.

  Such bearing systems, generally designated as anti-friction bearings, have very smooth surfaces which do not satisfactorily perform.

  forced oil circulation during oscillating movements

  Limited lants or vibratory of the type occurring in the operation of universal joints As is obvious to those skilled in the art, the appropriate lubrication of anti-friction bearings tends to depend on a continuous rotational movement of the components. Since the bearings associated with the universal joints perform only partial rotations, the oil circulates less than is desirable, which results in a relatively unsatisfactory behavior of the seal In addition, in dirty environments and / or corrosive, the lack of sufficient lubrication becomes extremely critical and can often cause premature failure of the journals In mileux loaded with moisture and / or corrosive, it can also occur a seizure

  further accentuating the wear and thus accelerating the

  improvement of the interface between the bearing and the trunnion.

  The invention relates to an improved lubrication device for anti-friction bearing and bearing journals of the type normally having

  smooth and / or rectified profiles used in universal joints

  salts Several lubricated and closely spaced and / or closely spaced bearings and grooves are arranged circumferentially around each trunnion.

  carried surfaces establishing contact surfaces for rollers

  Needle cups, and grooves for retaining lubricant between bearing and trunnion surfaces In a preferred embodiment, the bearing surfaces and grooves are uniformly spaced apart from each other.

  alternate way and are oriented in sensible

  perpendicular to the longitudinal axes of the

  In another preferred embodiment, the

  worn and the throats present, in part, discon-

  random intervals on the circumference of each

  rillon. A preferred method of manufacturing the improved spigot journals according to the invention comprises the steps of machining and heat treatment without

  the typical, intermediate or final stage of rectification

  Another preferred method comprises a roller burnishing operation of the front trunnion spans.

heat treatment.

  The invention will be described in more detail with regard to

  annexed drawings as examples which are in no way

  and in which: FIG. 1 is a plan view, partly in section, of a universal joint spider with improved trunnions according to the invention, this view also showing needle bearings and the associated rings; Figure 2 is a partial elevation of a preferred embodiment of the improved spigot according to the invention; FIG. 3 is a partial elevation of a

  another preferred embodiment of the trunnion

  born according to the invention; Figure 4 is a partial longitudinal section of a detail of grooves and bearings of a preferred embodiment of the journal according to the invention;

  FIG. 5 is a longitudinal section through

  of a detail of gorges or staves of another

  preferred embodiment of the trunnion according to the invention.

  tion; Figure 6 is a partial cross-section

  interface between a trunnion and a bearing

  guilles of a universal joint of the prior art;

  Figure 7 is a cross section through

  similar to that of Figure 6, showing the same

  interface of a universal joint comprising the improved trunnion according to the invention; and FIG. 8 is a plan view of the spider according to the invention in a preferred embodiment in which the bearings and grooves have

  partial and random discontinuities on the circu-

the trunnions.

  Figure 1 shows a spider 10 of the type used in a universal joint (not shown) In the preferred embodiment as described herein, the spider 10 has four improved trunnions 14 which extend radially outward next longitudinal axes AA or BB, from a central body 12 Each journal 14

  is housed in a needle bearing bearing bearing 16 comprising

  A plurality of rolling needles 24 housed in a cup-shaped ring 22 The cylinder of each pin 14 has an end portion 18 which abuts and slides against a complementary abutment surface 20 located within each bearing ring 22. 24 can freely rotate in a bearing cavity 8, defined by an annular space between the inner cylindrical surface of the ring 22 and the outer cylindrical surface of the journal 14. An elastomer friction ring 26 is mounted in each bearing ring 22 so as to to ensure proper radial positioning of the support needles 24, as is well known to those skilled in the art Elastomeric rings 28 are intended to protect the bearings of the outer dirt and other impurities The seals 28 also help retain a lubricant inside

of the cavity 8 of the bearing.

  FIG. 2 is a partial view of a preferred embodiment of the improved spigot 14 of the spider 10. The spigot 14 has spans 30 and grooves 32 which alternate with each other and which are spaced apart from one another to better

  hold the oil on the cylindrical surface of the trunnion 14.

  The spans 30 and the grooves 32 are especially identified

  letters A, B, C and D added to the numerical references

  in Figures 2, 3, 4 and 5, respectively, uniquely

  For clarity purposes, FIGS. 4 and 5 show more particularly two preferred embodiments of bearing surfaces 30 and grooves 32, respectively. In these two embodiments, grooves 32 constitute channels or channels for the flow of water. oil for lubricating journal bearings 30 and bearing needles 24 rolling on these bearing surfaces, while said bearing surfaces 30 constitute the actual bearing and bearing contact surfaces between journal 14 and pins 24 of the bearing grooves 32 of FIG. 4 show an embodiment produced by means of a machine tool, for example by means of a lathe or a milling machine. The groove 32 of FIG. 5, however, corresponds to an embodiment also carried out

  using such a tool, but then submitted to a

  roller burnishing to form on each edge of the groove 32 a protrusion 29 which extends slightly

above the bottom 27 of the throat.

  It will be apparent to those skilled in the art that the rolling needles 24 do not travel all the circumferential surface of the trunnion in the medium in which a universal joint is used. Referring to FIG. for example, that the bearing needle 24 as shown moves from the position indicated at 34 to that indicated at 36 and returns to 34, performing an oscillating movement which therefore occurs on a completely localized surface of the pin 14 the effect of such movement, if the complementary surfaces are smooth,

  for example, if they have been finely rectified, the lubricant

  As a result, it tends to be forced out of the way between points 34 and 36, resulting in the formation between these points of a contact zone which tends to be deprived of lubrication. that in most bearing applications of the anti-friction bearing type, a roller or a needle 24 rotates completely relative to an element 14, so that a wave 38 of oil moves continuously over the around the circular element

  14 As a result, the finely honed surfaces pre-

  feel in most elements in which are used anti-friction bearings are not prone to problems due to localized lack of oil

lubrication.

  Since the invention relates to the realization of appropriate lubrication in the case of an oscillatory or vibratory movement, we see in Figures 2 and 3, which represent the preferred forms

  embodiment of the invention, that the spans 30 defined

  the bearing contact surfaces for the bearing needles, and that the bearing surfaces 30 and the grooves 32 are

  all oriented in planes that are almost

  In FIG. 2, the bearing surfaces and grooves 30 and 32, respectively, follow individual annular paths around each journal cylindrical body. However, in the embodiment of FIG. In both cases, the preferred embodiments of each bearing and of each groove are such that each bearing is equidistant from the immediately adjacent bearing surfaces and each groove is

  equidistant from the immediately adjacent gorge.

  Referring now to FIG. 7, the more sensitive improvement can be more fully appreciated.

  lubrication of the contact zone between the

  14 and 24 rolling needles, this zone being between the points 34 and 36 of the oscillation

  and the improvement being due to the presence of the grooves 32.

  Thus, in FIG. 7, the lubricant 38 is not removed from the contact path between the points 34 and 36, but is rather retained in the grooves 32, between the latter points of contact. The depth of the grooves 32 is represented. by the space between the bottom of the groove 32, indicated by an arc 40, and the top of the range, indicated by an arc 42 On the other hand, the cylindrical contact zones, finely 'olies, between the pin 14 and the Roller 24, in the prior art interface shown in Fig. 6, cause the tendency of the lubricant to be removed from the contact path;

  points 34 and 36, along the arc 41 of fine contact

polished trunnion 14.

  A preferred method for producing journal bearings 32 and grooves 32 comprises coarse machining, then thermal treatment of the journals, without intermediate or final grinding and / or polishing operations. The braces are generally forged metal parts but, alternatively, they may consist of molded metal parts, as is

  well known to those skilled in the art Machining is preferably

  made at cutting speeds in the order of

  400 to 600 rpm The feed speeds of the tool

  are preferably between 0.38 and 0.50 mm per turn Preferred cutting depths are included

between 1.5 and 2.3 mm.

  A machining operation performed at the preferred feed rates and cutting depths, as indicated above, makes it possible to efficiently obtain

  a surface roughly turned on a metal trunnion

  that typical, as well as the man of the art can appreciate it. In the helical embodiment of FIG. 3, such a surface can be obtained by constant contact of the tool over the entire length of the longitudinal axis of the trunnion body. The characteristic of the preferred machining parameters is a trend of the tool to cut from time to time the bearing surfaces 30 and the grooves 32 in a partially and randomly discontinuous manner, on the circumference of each trunnion, thus giving the appearance as shown in FIG. 8 However, the discontinuities produced do not do not interfere with the improved lubrication of the invention At this stage, as mentioned above with reference to FIG. 5, an optional roller burnishing operation may be performed by means of a rolling element which penetrates the surface of the bearings, preferably at a depth of

the order of 0.125 to 0.25 mm.

  The preferred heat treatment step comprises carburizing the journals in a nitrogen atmosphere at a temperature of about 900 to 9550 C, followed by quenching.

trunnions in the oil.

  The invention as described herein provides a substantially improved means

  lubrication of trunnions and bearings

  associated guilleas, for use in joints

universal.

  It goes without saying that many modifications can be made to the described universal joint and

  represented without departing from the scope of the invention.

  For example, annular grooves may also retain corrosive particles and other debris to prevent them from reaching surfaces in contact. Otherwise, such Particles would produce destructive effects due to their presence at the contact interface of the rolling elements. In addition, for example, the bearings and grooves can, alternatively, be made on the inner cylindrical surface of the bearing ring 22.

Claims (19)

  1 universal joint comprising a spider (10) which comprises cylindrical pins (14) projecting radially, each pin having a longitudinal axis, two rotating members having forks intended to articulate on the journals, each fork defining an annular cavity for receiving one of the trunnions and a plurality of needle bearings (16) being disposed between each fork and the corresponding trunnion, the universal joint being   characterized in that each pin present in its cir-   multi-port conference (30) and a plurality of alternately spaced lubrication grooves (32), the   grooves being arranged so as to communicate by rolling   the bearing needles to ensure lubrication, the bearing surfaces having rolling contact surfaces for the needles, the grooves   and the staves being oriented in sensible planes   perpendicular to the longitudinal axis of each trunnion.   2 universal joint according to claim 1, characterized in that each bearing is equidistant from the immediately adjacent bearing surfaces and in that each   throat is equidistant from the immediately adjacent gorge.   Universal joint according to claim 2, characterized in that the bearings and grooves follow helical paths around each cylindrical pin. 4 universal joint according to claim 2, characterized in that each of the spans and grooves   follows a separate annular path around each cylindrical ridge.   Universal joint according to one of the claims   3 and 4, characterized in that the grooves and the staves are interrupted partially and randomly on   the circumference of each trunnion.   6 universal joint cross, characterized in that it comprises a plurality of cylindrical pins (14), projecting radially and arranged to be engaged with forks of two rotary elements, each pin having several spans (30) and grooves (32). ) spaced radially and circumferentially on its surface.   Crossbar according to claim 6, characterized   rised in that each of the spans and gorges is equi-   away from the immediate reach or throat.   Crossbar according to claim 7, characterized   rised in that the litters and throats follow   helicoidal paths around each cylindrical spigot.   Crossbar according to claim 7, characterized   in that each of the spans and grooves follows a separate annular path around each cylindrical spigot.   Cross member according to one of the claims   8 and 9, characterized in that the spans and grooves are discontinuous partially and randomly on   the circumference of each trunnion.   11 Method of manufacturing a spider (10)   universal joint, this brace   cylindrical ribs (14) which protrude radially and which are arranged to engage with forks of two rotating members, each journal having a plurality of radially spaced spans (30) and grooves (32) circumferentially, the method being characterized in that it consists of machining the bearings and grooves in the journals, and to submit these   last to a heat treatment.   The process according to claim 11, characterized   in addition to subjecting the litters   from the trunnions to a roller burnishing before   heat of said trunnions.   Method according to one of the claims 11   and 12, characterized in that the machining is performed at cutting speeds of the order of 400 to 600 rpm and at   advance speeds of the order of 0.38 to 0.50 mm per revolution.   The method of claim 13, characterized   in that it also consists in using a   machining cutter of the order of 1.5 to 2.3 mm and roll-rolling with a rolling element penetrating the surface of the scopes,   at a depth of the order of 0.125 to 0.25 mm.   Process according to claim 14, characterized   in that the heat treatment consists in subjecting the trunnions to carburation in an atmosphere comprising a nitrogen gas, at a temperature of the order   from 900 to 9550 C, then dip the trunnions in the oil.   16 Universal joint bearing element pre-   sensing an axis, characterized in that it has several bearing surfaces (30) and grooves (32) spaced alternately   and arranged approximately perpendicular to the axis.   17 A method of finishing a bearing surface of a universal joint element, characterized in that it consists in rough machining said surface and in finishing by a heat treatment the surface roughly machined.   18. Process according to claim 17, characterized   In addition, the method further comprises subjecting the bearing surface to roller burnishing prior to the heat treatment.   Method according to one of the claims 17   and 18, characterized in that machining is performed at cutting speeds in the range of 400 to 600 rpm and feed rates in the range of 0.38 to 0.50 mm per revolution. .   The process according to claim 18, characterized   in that it also consists in using a depth   machining cutter in the order of 1.5 to 2.3 mm and roll-burn using a rolling element penetrating the surface to a depth from 0.125 to 0.25 mm.   Method according to claim 20, characterized   in that the heat treatment consists of a carburization of said surface in an atmosphere consisting of a nitrogen gas, at a temperature of the order of 900 to 9550 C, and then a quenching of this surface in the oil.