FR2833664A1 - Steering column bearing has races for rolling bodies formed by wires inside inner and outer rings - Google Patents

Abstract

The bearing, especially for a steering column, consists of inner (2) and outer (3) rings for rolling bodies (8) in contact with races. The race in at least one ring is formed by two wires (4, 5) and an axial pressure ring (10) which has a truncated conical shape in its free state. The pressure ring is located between one of the wires (4) and the inner surface of a bearing ring rim (3b). Both the bearing rings can have a trough-shaped cross-section, with races formed by wires (4, 5, 6, 7) in both rings.

Description

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 Rolling bearing, especially for steering column.

 The invention relates to the field of rolling bearings, especially for steering columns.

d'une cage. L'élément élastique présente une forme annulaire à section 1 > en L avec une portion axiale en contact avec une portion axiale de la bague extérieure et une portion radiale en contact avec une portion radiale de la bague extérieure. Des crochets sont formés à l'extrémité libre de la portion axiale de l'élément élastique, du côté intérieur et assurent la retenue axiale d'une rondelle consistant en un élément annulaire tronconique. La rondelle comprend un bord intérieur en contact avec l'autre portion axiale de la bague extérieure et orienté axialement du côté opposé aux éléments roulants et un bord extérieur en contact avec l'un des quatre fils et avec les crochets de l'élément élastique, et orienté axialement du côté des éléments roulants. Document FR-A-2 669 690 discloses a bearing comprising an outer ring with a U-shaped section, an inner ring with a U-shaped section, a resilient element disposed in the outer ring, and four treated steel wires, two of which are arranged in the inner ring in the connection areas between its axial and radial portions and two in the bore of the elastic element, and rolling elements such as balls disposed in contact with the son which constitute the rolling tracks of the rolling elements. The son are in the form of annular rods whose ends come end to end when they are in place. The rolling elements may be contiguous in the circumferential direction or be regularly spaced from one another by means of

a cage. The elastic element has an annular shape with a section 1> L with an axial portion in contact with an axial portion of the outer ring and a radial portion in contact with a radial portion of the outer ring. Hooks are formed at the free end of the axial portion of the elastic member on the inside and provide axial retention of a washer consisting of a frustoconical annular element. The washer comprises an inner edge in contact with the other axial portion of the outer ring and oriented axially on the opposite side to the rolling elements and an outer edge in contact with one of the four son and with the hooks of the elastic element, and oriented axially on the side of the rolling elements.

la bague intérieure, les fils, les corps roulants, la rondelle, et l'élément Z : D élastique. Puis on monte cette unité dans une bague extérieure dont l'une des portions radiales n'est pas encore formée et est donc à

section en L, puis on rabat la bague extérieure pour former ladite t > portion radiale. To mount such a bearing, a unit comprising

the inner ring, the wires, the rolling bodies, the washer, and the elastic Z: D element. Then we mount this unit in an outer ring of which one of the radial portions is not yet formed and is therefore

section L, then flap the outer ring to form said t> radial portion.

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 Thus, a four-point contact bearing is able to operate as well under axial load as under radial load or under combined load.

 Such bearings are frequently used in steering columns that accommodate bearings whose dimensional and functional accuracy need not be very high. In order that the bearing can operate without play with a calibrated preload, a conical preload washer is provided between one of the radial portions of the outer ring and the corresponding ring. In the uncompressed state, the washer has a frustoconical profile whose cone apex is directed in a direction opposite to the balls.

When one comes to form the last radial edge of the outer casing, the washer is compressed which initially has a slightly conical shape in the form of Chinese hat. The puck then tends to take a flat shape, the top of the cone getting closer to the balls. The axial force exerted by the washer thus creates a prestressing force between the balls and the rods on the one hand, between the rods and the envelopes on the other hand, thus catching up all the residual gaps between these elements.

 Such types of bearings with four points of contact by wire, however, have certain disadvantages. On the one hand, they have a relatively large number of elements. On the other hand, the inner ring to be mounted with a large tightening on the rotating shaft, the radial deformations of said ring are important, which causes a change in the play or the internal preload of the bearing, especially in the case where we would like to use a device without a preload washer.

 On the other hand, prestressed four-wire devices wear out relatively quickly over time.

 The invention proposes to remedy the disadvantages described above.

 The invention provides a rolling bearing very rigid and economical.

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 The rolling device, according to one aspect of the invention, is of the type comprising raceways, at least one wire forming one of the raceways, at least one rigid envelope in contact with said wire, at least one ring massive, a row of rolling elements arranged in contact with the wire and the massive ring.

The massive ring is almost indeformable and the bearing has a significant axial and radial rigidity.

 In one embodiment of the invention, the device comprises two son, the envelope being in contact with said son.

 In one embodiment of the invention, the envelope comprises an axial portion and two radial portions disposed at the ends of the axial portion, one wire being in contact with the axial portion and one of the radial portions and the other wire. being in contact with the axial portion and the other radial portion.

 In one embodiment of the invention, the solid ring comprises a V-shaped cross-section groove with two frustoconical surfaces each forming a rolling track.

massive comprend une gorge à section droite en V avec deux surfaces 1 bombées convexes formant chacune une piste de roulement. In another embodiment of the invention, the ring

massive comprises a straight V-section groove with two convex convex surfaces 1 each forming a raceway.

 In another embodiment of the invention, the solid ring comprises a straight V-section groove with two concave surfaces each forming a raceway.

 In one embodiment of the invention, a wire has a round cross section.

 In another embodiment of the invention, a wire has a cross section comprising a convex portion, said convex portion forming a raceway. Said wire is symmetrical with respect to a radial plane.

 Preferably, the envelope is made of sheet metal, for example steel, and the wire is metal, in particular steel.

 A preload washer can be mounted in the bearing in contact with the envelope and with a wire. The washer may consist of a frustoconical annular element in the free and open state

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 in its central part. Such a Belleville washer is particularly economical.

 However, a Belleville washer having a very flat conical profile and therefore little axial asymmetry, is very difficult to automatically orient by means of a vibratory bowl for automated assembly of the bearing. There is therefore a significant risk of upside down preload washers in the bearing.

 In a preferred embodiment of the invention, the device comprises a washer consisting of an annular element L-section open in the central part, with a frustoconical branch in the free state. The washer may comprise a frustoconical portion in the free state and an axial flange extending outwardly of the bearing.

The axial flange prevents a possible reversal of the frustoconical portion which has a single stable state. Such a washer is very easy to automatically orient in an assembly line which reduces the risk of mounting upside down and unsuitable for a possible reversal, while remaining economical and without detrimental influence to the compactness of the bearing whose dimensions are unchanged .

 Advantageously, the axial flange is circumferentially continuous and forms the central opening of the prestressing element. The axial flange may extend from the inner edge of the frustoconical portion axially opposite the rolling elements.

Advantageously, the axial flange is disposed in a bore of the outer casing. The prestressing washer is thus easy to center relative to the outer casing, simply by passing the axial flange in said bore. The axial length of the axial flange may be less than the thickness of the corresponding envelope, in particular the thickness of the radial portion of the envelope with which the axial flange is in contact. This keeps the outer dimensions of the bearing without changing its size.

The axial flange may have a diameter slightly less than that of a bore of the outer casing with which it is adapted to cooperate. The frustoconical portion may be in contact with one of the son and with a radial wall of the outer casing. The outer edge

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 the frustoconical portion may be in contact with said wire, while the inner edge is in contact with said radial wall. The frustoconical portion may have, in the mounted state, an angle at the apex of the cone varying from 160 to 180 with respect to a radial plane. In the free state, the frustoconical portion may have an angle at the top of the cone of the order of 140 to 170.

 Advantageously, the frustoconical portion is circumferentially continuous.

 In one embodiment of the invention, the envelope is annular and may be provided with a radial portion of smaller thickness than the axial portion and the other radial portion to facilitate its folding after insertion of the elements. of the bearing to enter.

 In other words, there is provided a bearing comprising an envelope, one or two son mounted in contact with the casing, a row of rolling elements arranged in contact with the son, and a machined solid ring.

contact avec ledit fil, au moins une bague massive, une rangée C > Z-D d'éléments roulants disposés au contact du fil et de la bague massive. The invention also relates to a steering column comprising a shaft and two bearings mounted on the shaft. At least one of the bearings comprises raceways, at least one wire forming one of the raceways, at least one envelope

contact with said wire, at least one solid ring, a row C> ZD of rolling elements arranged in contact with the wire and the solid ring.

The bearings can be arranged in appropriate housings.

- la figure 2 est une demi vue correspondant à la figure 1 ; - la figure 3 est une demi-vue en coupe axiale d'un palier à roulement selon un deuxième mode de réalisation de l'invention ; - la figure 4 est demi vue en coupe axiale d'un palier à roulement selon un troisième mode de réalisation de l'invention ; et The present invention will be better understood on studying the detailed description of an embodiment taken by way of nonlimiting example and illustrated by the accompanying drawings, in which: - Figure 1 is an axial sectional view of a rolling bearing according to a first embodiment of the invention mounted on a shaft and disposed in a housing;

- Figure 2 is a half view corresponding to Figure 1; FIG. 3 is a half-view in axial section of a rolling bearing according to a second embodiment of the invention; - Figure 4 is a half axial sectional view of a rolling bearing according to a third embodiment of the invention; and

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 - Figure 5 is a partial view in axial section of a rolling bearing according to a fourth embodiment of the invention.

 As can be seen in Figure 1, the bearing 1 comprises an inner ring 2, an outer casing 3, two son 4 and 5, a row of rolling elements 6, and a cage 7. The inner ring 2 is of type massive. A ring of massive type means a ring whose shape is obtained by machining with chip removal (turning, grinding) from tubes, bars, blanks forged and / or rolled. The inner ring 2 comprises a bore 2a of cylindrical shape delimited by radial front surfaces 2b and 2c, and an outer cylindrical surface 2d from which is formed a circular groove 8 with a V-section, that is to say having two frustoconical surfaces 8a and 8b symmetrical on either side of a radial plane, with filleting. The frustoconical surfaces 8a and 8b form rolling tracks on which the rolling elements 6 move.

 Economically, the surfaces of the races 8a, 8b can be obtained directly by turning or rolling, without subsequent rectification.

 The outer casing 3 has a U-shaped annular shape with an axial portion 3a, a radial wall 3b and a radial wall 3c. The radial wall 3c has a thickness less than the thickness of the axial portion 3a and the radial portion 3b and a length, in the radial direction, less than the length of the radial portion 3b. In other words, the space separating the radial portion 3c from the outer cylindrical surface 2d is greater than that separating the radial portion 3b from the outer cylindrical surface 2d.

 The son 4 and 5 are in the form of annular rings whose ends come end to end and are arranged in the outer casing 2 in direct contact therewith. The wire 4 is disposed in contact with the axial portion 3a and with the axial portion 3b. The wire 5 is disposed in contact with the axial portion 3a and with the radial wall 3c. The rolling elements 6, here balls, are arranged between the son 4 and 5, and the frustoconical surfaces 8a and 8b forming

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 runways in contact with each of the wires and each of the paths and are kept circumferentially spaced by the cage 7.

This produces a rolling four points of contact.

 The cage 7 comprises an annular portion 7a disposed on the side of the radial portion 3c radially between the free end of the radial portion 3c and the cylindrical surface 2d of the inner ring 2.

 For reasons of economy and mechanical strength, the ring 2, the casing 3, the son 4 and 5 and the rolling elements 6 are generally made of steel of appropriate grades. The ring 2 can be made of hardened steel 100C6 as well as the balls 6. The son 4 and 5 can be made of pre-treated steel type "piano wire". The envelope 3 is monobloc and made by folding or stamping mild steel sheet.

l'épaisseur radiale de la bague intérieure 2, l'emmanchement peut être ZD effectué avec un serrage élevé sans déformation radiale importante des chemins de roulement formés par les surfaces 8a et 8b et donc sans risque de réduction significative du jeu interne du roulement. Grâce à l'utilisation d'une bague intérieure massive 2, on obtient ainsi un roulement de rigidité élevée et présentant un jeu axial ou radial nul ou quasi nul ce qui est souhaité pour les roulements de colonne de direction où le conducteur ne doit pas ressentir un tel jeu. La combinaison des chemins de roulement sur fils d'une part et sur bague massive d'autre part permet de réduire de façon significative l'usure au niveau des surfaces de contact avec les éléments roulants et par conséquent évite une prise de jeu néfaste du roulement. The bearing 1 is mounted on a shaft 9 which has a cylindrical surface 10 and a shoulder 11. The inner ring 2 is fitted on the cylindrical surface 10 by its bore 2a and the radial surface 2c abuts against the shoulder 11. at

the radial thickness of the inner ring 2, the fitting can be ZD performed with high tightening without significant radial deformation of the raceways formed by the surfaces 8a and 8b and therefore without risk of significant reduction of the internal clearance of the bearing. Thanks to the use of a solid inner ring 2, a high rigidity bearing is thus obtained and having zero or almost zero axial or radial play, which is desired for steering column bearings where the driver must not feel such a game. The combination of raceways on son on the one hand and massive ring on the other hand significantly reduces wear on the contact surfaces with the rolling elements and therefore avoids a grip harmful game of the bearing.

 The bearing 1 is mounted in a housing 12 provided with a bore 13 in which is formed an annular groove 14.

The casing 3 is fitted into the bore 13. A stop element 15, for example a circlip, is disposed in the groove 14 and projects inwards. The radial wall 3b of the casing 3 is in contact, in

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 general bearing against the stop element 15. The bearing 1 can thus transmit a significant axial force exerted on the shaft 9 in the direction of the arrow 16. The shoulder It transmits this force to the solid inner ring 2 which transmits it through the frustoconical surface 8b to the rolling elements 6. The rolling elements 6 transmit it to the wire 4 which bears on the radial wall 3b of the casing 3 itself bearing on the stop element 15. Another bearing may be mounted at the other end of the shaft 9 to absorb the axial forces on the shaft exerted in the direction opposite to the arrow 16. The bearing 1 could, however, absorb on its own axial forces in both meaning. It would suffice to provide on the shaft and on the housing 12 additional axial locking means so that the bearing 2 is immobilized axially in both directions with respect to the housing 12 and to the shaft 9.

 In Figure 3, the references of elements similar to those of Figures 1 and 2 have been retained. The inner ring 2 comprises an annular groove 17 in place of the groove 8. The circular groove 17 has convex convex generatrices 17a and 17b forming raceways. In other words, in cross section along a plane passing through the axis of the bearing, the groove 17 comprises a convex portion, a concave bottom 17c and another convex portion. The groove 17 is symmetrical with respect to a radial plane passing through the center of the rolling elements 6.

l'axe du roulement, la gorge 18 comprend deux portions concaves e adjacentes. La gorge 18 est symétrique par rapport à un plan radial passant par le centre des éléments roulants 6. In Figure 4, the references of elements similar to those of Figures 1 and 2 have been retained. The inner ring 2 comprises a circular groove 18 in place of the groove 8. The groove 18 has concave generatrices 18a and 18b forming raceways. In other words, in section according to a plan going through

the axis of the bearing, the groove 18 comprises two concave portions e adjacent. The groove 18 is symmetrical with respect to a radial plane passing through the center of the rolling elements 6.

 In addition, the bearing 1 comprises an axial prestressing element 19 provided with a frustoconical portion 20 and an axial flange 21 forming the central opening of the prestressing element. The flange

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 axial 21 is of axial length less than or equal to the thickness of the radial portion 3b of the outer casing 3 and is disposed in the bore of said radial portion 3b. For easy assembly, the diameter of the axial flange 21 is very slightly less than the inside diameter of the radial portion 3b.

 The frustoconical portion 20 extends from the end of the axial flange 21 located on the side of the rolling elements 6 and is directed radially outwards, so that its end is adapted to be in contact with the wire 4. The inner edge 20a of the frustoconical portion 20 is in contact with a radial surface of the radial portion 3b close to its free end and the outer edge 20b is in contact with the wire 4. The prestressing element 19 is thus supported on the radial portion 3b of the outer casing 3 and exerts a permanent axial force on the wire 4.

 The prestressing element 19 has a single stable state due to the presence of the axial flange 21 which is connected to the inner edge 20a of the frustoconical portion 20. In addition, the prestressing element 19 being strongly asymmetrical in the axial direction, its orientation for automatic assembly can be easily achieved by a vibratory bowl, which then allows to position it in a specific direction in the outer casing 3.

 In the free state, the frustoconical portion 20 having an angle with a higher radial plane than in the assembled state illustrated in FIG. 4. During assembly, the rolling elements 6 and the cage 7 are arranged on the feed paths. bearing of the inner ring 2, the preloading element 19, the wire 4, the rolling elements subassembly 6-cage 7-inner ring 2, and the wire 5 in the casing 3 are arranged.

Then, the initially axial radial portion 3c is folded to give it a radial shape while maintaining the radial portion 3b and causing partial crushing of the frustoconical portion 20 of the prestressing element 19.

 The tubular axial flange of the prestressing element increases the rigidity of the frustoconical portion and prevents any accidental reversal of said frustoconical portion on itself.

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 It is thus safe to completely crush the preload washer to give the frustoconical portion a flat shape without risk of overturning. On the other hand, the prestressing element has a frankly asymmetrical profile in the axial direction. It is therefore very easy to orient this piece by means of a vibrating bowl. It is thus easy to automate the assembly of the bearing and benefit from the corresponding reduction in manufacturing cost. The manufacturing process is made more reliable by considerably limiting the risk of mounting upside down or accidental turning of the preload washer when it is put in place or afterwards. The axial flange of the prestressing element promotes its pre-centering in the outer casing, which also ensures a correct relative radial centering of the periphery of the frustoconical portion relative to the rods forming the raceway with which they cooperate. This also facilitates the automation of the assembly of the elements. Finally, the axial size of the bearing is not affected because the axial dimensions of the axial flange of the washer are less than or equal to the thickness of the corresponding envelope.

 In Figure 5, the references of the elements similar to those of Figures 1 and 2 have been retained. The son 22 and 23 replacing the son 4 and 5 are annular. Their section by a plane passing through the generally circular axis of the bearing, has two recesses 24 and 25 in an arc of radius substantially equal to the radius of the rolling elements 6. The recesses 24 and 25 are arranged on the inside of the wires. 22 and 23 and are symmetrical with respect to a radial plane passing through the center of the section of said wires 22 and 23. Thus the son 22 and 23 are identical, which reduces the number of different parts of the bearing 1 and can be mounted without prior orientation which is economic. The recesses 24 and 25 form raceways for the rolling elements 6 and provide substantial rolling surfaces reducing the wear of the wires 22 and 23 and the rolling elements 6.

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 Whatever the embodiment of the invention, the bearing obtained is of simple construction, economical, robust, particularly rigid and compact.

 The bearing according to the invention can be mounted with a strong tightening on the shaft without substantial modification of the play or internal preload of the bearing.

 Finally, the bearing according to the invention has a very low wear over time and therefore a very high stability over time of the play characteristics or internal prestressing.

Claims (11)

1-rolling device (1), characterized in that it comprises raceways, at least one wire (4) forming one of the raceways, at least one casing (3) in contact with

 said wire, at least one solid ring (2), a row of rolling elements (6) arranged in contact with the wire and the solid ring.  2-Device according to claim 1, characterized in that it comprises two son (4,5), the envelope being in contact with said son.  3-Device according to claim 2, characterized in that the casing (3) comprises an axial portion (3a) and two radial portions (3b, 3c) disposed at the ends of the axial portion, a wire being in contact with the axial portion and one of the radial portions and the other wire being in contact with the axial portion and the other radial portion.  4-Device according to any one of the claims

 previous, characterized in that the solid ring (2) comprises Z: D a groove (8) with a cross section V with two frustoconical surfaces (8a, 8b) each forming a raceway.  5-Device according to any one of claims 1 to 4, characterized in that the solid ring comprises a groove section (17) V-shaped with two curved convex surfaces (17a, 17b) each forming a raceway.  6-Device according to any one of claims 1 to 4,

 characterized in that the solid ring comprises a groove 1 section (18) right V with two concave surfaces (18a, 18b) each forming a raceway.  7-Device according to any one of the preceding claims, characterized in that a wire has a round cross section.  8-Device according to any one of the preceding claims, characterized in that a wire (22) has a section <Desc / Clms Page number 13>  cross section comprising a convex portion (25), said convex portion forming a rolling track.  9-Device according to claim 8, characterized in that said wire is symmetrical with respect to a radial plane.  10-Device according to any one of the preceding claims, characterized in that it comprises a washer consisting of an annular element (19) L-section open in the central part, with a frustoconical portion in the free state and a axial portion.  11-steering column comprising a shaft and two bearings mounted on the shaft, characterized in that at least one of the bearings comprises raceways, at least one wire (4) forming one of the paths of rolling, at least one envelope (3)

 in contact with said wire, at least one solid ring (2), a row Z> of rolling elements (6) arranged in contact with the wire and the solid ring.