ITTO970097A1 - THRUST BEARING FOR CLUTCH WITH SELF-ALIGNMENT ELA STICO. - Google Patents

Description

DESCRIPTION of the industrial invention entitled "THRUST BEARING FOR CLUTCH WITH ELASTIC SELF-ALIGNMENT ORGAN"

The present invention relates to a thrust bearing for friction which comprises a rolling bearing mounted on a guide bush provided with a tubular part and a radial collar on which an operating member of the thrust bearing rests to move the thrust bearing. rolling axially so that this acts through its rotating ring on the diaphragm of a clutch and thus performs its maneuver.

From the German patent application 2046 282 (FICHTEL and SACHS), a self-aligning organ consisting of an open metal ring formed by a bent metal band with the shape of an octagon is known. However, this metal ring does not participate in the axial retention of the thrust bearing on the guide bush, which requires additional pieces to perform this function. The elasticity of this member is not constant according to the axial displacement direction of the rolling bearing, which can cause misalignment problems.

Also known, from French patent application 2663 702 (SKF), is a thrust bearing for friction provided with a self-aligning member in the form of a rubber sleeve arranged between the non-rotating ring of the rolling bearing and the guide. The sleeve comprises ribs capable of deforming radially so that the thrust bearing aligns itself, during operation, on the axis of rotation of the clutch diaphragm. This device is entirely satisfactory but is limited to applications operating at relatively low temperatures.

The present invention relates to the realization of a clutch thrust bearing which comprises an elastic self-alignment and axial retaining member of the non-rotating ring which can be made in a simple, economical and compact way, which allows easy assembly while guaranteeing a solidarity and constant elasticity whatever the movement of the rolling bearing and being able to withstand high temperatures.

The clutch thrust bearing according to the invention is of the type comprising a rolling bearing equipped with a rotating ring and a non-rotating ring and mounted on a guide bush equipped with a tubular part and a radial collar on which it is inserted. bearing the non-rotating ring of the rolling bearing, an elastic self-aligning member of the non-rotating ring with respect to the guide bush being arranged radially between the rotating ring and a tubular part of the guide bush. The elastic self-aligning member comprises a metal band the ends of which are mutually approached to form a ring, the aforementioned band being provided with elastic tabs and bearing surfaces which cooperate with retaining surfaces of the guide bush and of the non-rotating ring.

Thanks to this metal band, the thrust bearing for friction can withstand high temperatures while having a simple and economical structure, the metal band constituting the elastic self-aligning member which also serves to axially retain the rolling bearing in contact with the guide bush.

The elastic tabs are advantageously separated from each other at least by means of a transverse bar. The spring tabs can be sheared in the metal strip in a circular direction and can be supported by the cross bars or they can be sheared in the metal strip in an axial direction.

In an embodiment of the invention, the metal strip comprises a plurality of corrugations regularly distributed in an annular manner and intended for axial retention of the non-rotating ring while facilitating the centering of the metal strip in the cylindrical cavity of the non-rotating ring.

In another embodiment of the invention, the metal strip comprises a plurality of radial tabs which form bearing surfaces which cooperate with radial surfaces of the non-rotating ring. The radial tabs can be sheared on one edge of the metal strip on both edges or in the center of the metal strip. In the latter case, the radial tabs can be sheared near the elastic tabs.

In order to ensure the sealing of the rolling bearing, an edge of the metal strip advantageously forms a narrow passage with the rotating ring of the rolling bearing.

In an embodiment of the invention, the metal strip is arranged between a shoulder of the tubular part and the collar of the guide bush. The tabs protrude from the metal band in the direction of the non-rotating ring, their edges forming thrust surfaces designed to cooperate with the non-rotating ring. Preferably, the non-rotating ring is provided with a circular groove capable of cooperating with the bearing surfaces of the elastic tabs.

In another embodiment of the invention, the guide bushing comprises a second tubular part surrounding the non-rotating outer ring of the rolling bearing, the metal band being disposed between the outer surface of the non-rotating ring and the cylindrical cavity of the second tubular part.

The invention will be well understood with the study of the detailed description of some embodiments taken as absolutely non-limiting examples and illustrated by the attached drawings in which:

Figure 1 is a sectional side view of a clutch thrust bearing according to a first embodiment of the invention;

Figure 2 is a sectional view according to II-II of Figure 1;

Figure 3 is an enlarged view of a detail of Figure 1 which illustrates in particular the stripping of the tubular part of the guide bush;

Figures 4 and 5 are external views of the plate after the blanking of two variants of the metal strip;

Figure 6 is a cross-sectional view of the metal strip of Figure 5 after the complete forming of the strip;

Figure 7 is a longitudinal sectional view of the metal strip of Figure 5 after the complete forming of the strip;

Figures 8 to 12 are external flat views after the blanking of different embodiments of the metal strip;

Figure 13 is a cross-sectional view of the metal strip of Figure 9 after the complete forming of the strip;

Figure 14 is a longitudinal sectional view of the metal strip of Figure 10 after the complete forming of the strip;

Figure 15 is a partial sectional view of a clutch thrust bearing fitted with the variant of the metal band of Figure 14;

Figure 16 is a variant of Figure 15; Figure 17 is a sectional view similar to Figure 2 of the thrust bearing for friction fitted with the metal band of Figure 8;

Figure 18 is a partial sectional view of a clutch thrust bearing according to another embodiment of the invention;

Figure 19 is a flat view of the metal strip of Figure 18;

Figure 20 is a side view of the metal strip of Figure 18;

Figure 21 is a partial section of a clutch thrust bearing according to another embodiment of the invention;

Figure 22 is a flat view of the metal strip of Figure 21;

Figures 23 to 25 are plate views of variants of metal strips;

Figure 26 is a longitudinal section view of a variant of the metal strip of Figure 21;

Figure 27 is a partial sectional view of a clutch thrust bearing according to another embodiment of the invention;

Figure 28 is a flat view of the metal strip of Figure 27;

Figure 29 is a cross-sectional view of the metal strip of Figure 27; And

Figure 30 is a partial sectional view of a clutch thrust bearing according to another embodiment of the invention.

As shown in Figures 1 and 2, the clutch thrust bearing according to the invention comprises a rolling bearing 1 mounted on a guide bush 2, which is advantageously made of synthetic material and which comprises a tubular portion 3, which can sliding with respect to a guide tube 4 shown with dashed lines in Figure 1, and a radial collar 5. The rolling bearing 1 comprises an inner ring 6 with a thin wall, made by drawing a sheet or a tube, which has a toric rolling plane 7 for a crown of balls 8 retained in a cage 9. The inner ring 6 also includes an extension directed outwards in the form of a radial collar 10 which comes into rubbing contact on the front surface inside of the radial collar 5.

The rolling bearing 1 is completed by an outer ring 11 equally with a thin wall, made by drawing a sheet or a tube, which has a toric rolling plane 12 for the balls 8 as well as a radial portion 13 which comes into contact with the surface of the diaphragm 14 of a friction device during the longitudinal displacement of the thrust bearing assembly with respect to the guide tube 4 on which the guide bush 2 slides. The rolling bearing 1 is protected by a protective side panel 15 fixed to the outer ring 11.

The radial collar 5 of the guide bush 2 has a metal ring 16 on which the aforementioned radial collar 5 is over-molded. This ring 16, which has preferably undergone a surface hardening treatment, serves as a contact surface for an operating member 17 which is shown with dashed lines in Figure 1 and exerting an effort in the axial direction to cause displacement of the thrust bearing as a whole during a disengagement operation.

The axial integration of the operating member 17 with respect to the guide bushing 2 is carried out by means of retaining portions 18 which form hooks arranged on the external diameter of the radial collar 5 of the guide bushing 2. The assembly of the operating member 17 it is carried out by means of an axial thrust which causes the bending of the retaining portions 18 of the guide bush 2.

An elastic self-alignment and axial retaining member of the non-rotating ring 6 with respect to the guide bush 2, which is indicated by 19 as a whole and which is in the form of a metal band, is arranged radially between the aforementioned non-rotating ring 6 and the tubular part 3 of the guide bushing 2. The metal strip 19 forms, after positioning, a closed ring which comprises elastic tabs 20 and corrugations 21, 22 regularly distributed along the strip.

As can be seen more particularly in Figure 2, the metal strip 19 of small thickness has a slightly larger diameter than the tubular part 3 of the guide bushing 2 and is centered thereon by means of the elastic tabs 20. The free end of the tubular part 3 comprises a strip 3a on its external diameter (Figure 1), which is in contact with the edge 20a of the elastic tabs 20 thus preventing the metal band 19 from moving axially towards the outside of the guide bush 2. The edge 20a of the elastic tabs 20 thus forms a resting surface of the metal strip 19 against the retaining surface formed by the shoulder 3a.

The corrugations 21, 22 of the metal strip 19 are located at the lateral ends of this. The undulations 21, located on the outer side of the non-rotating ring 6, have their edges 21a in axial contact with the radial end surface 6a of the non-rotating ring 6. The edges 2a of the corrugations 21 thus form supporting surfaces in contact with the radial end surface 6a of the non-rotating ring 6 and thus retain the non-rotating ring 6 with respect to the metal strip 19 and the guide bushing 2 against an axial displacement towards the outside, that is towards the diaphragm 14. The undulations 22, located on the side of the guide bushing 2, are in contact with a cylindrical cavity of the non-rotating ring 6 and maintain the centering of the metal strip 19 on the non-rotating ring 6.

The thrust bearing for friction illustrated in figure 3 is identical to that of figure 1 except for the non-rotating ring 6 whose free end from the outer side, i.e. from the side opposite the radial portion 10, ends with a radial surface 6a which corresponds to the thickness of the sheet metal forming the aforementioned non-rotating ring 6.

As can be seen more particularly in Figures 4 to 7, in which the metal strip 19, used in the embodiments illustrated in Figures 1 and 3, is shown before assembly in the free state, i.e. flat, the aforementioned metal strip 19 comprises on its lateral ends two portions of tape 23, 24 connected to each other by means of transverse bars 25. The portions of tape 23 and 24 and the transverse bars 25 define windows 26. The corrugations 21, 22 of the metal band 19 are respectively formed in the portions of tape 23, 24 at the level of a window 26. The tabs 20 extend in a circular direction starting from the cross bars 25 and protrude in the opposite direction to that of the undulations 21, 22.

In the embodiment illustrated in Figure 4, a transverse bar 25 on two supports an elastic tab 20. The subsequent transverse bar 25 being devoid of it. In the embodiment illustrated in Figures 5 to 7, each transverse bar 25 supports an elastic tab 20. This embodiment ensures a firm centering of that of Figure 4.

The metal strip 19 is manufactured in the following way. The windows 26 are punched by punching a solid metal strip, for example of spring steel. According to the embodiment chosen (figure 4 or figure 5) a punching tool with a suitable shape is used to obtain a transversal bar 25 without a tongue 20 or on the contrary equipped with a tongue 20. Then by bending their shape is given to the elastic tabs 20 and at the undulations 21, 22. The metal strip 19 is cut to the desired length according to the type of friction so that the metal strip 19 forms a ring after its assembly. The metal strip 19 is arranged inside the cylindrical cavity of the non-rotating ring 6 of a rolling bearing 1, the ends of the metal strip 19 being in mutual contact and possibly overlapping. Since the metal strip 19 tends to resume its initial flat shape, it locks by itself with respect to the non-rotating ring 6. To proceed with the assembly of the assembly formed by the rolling bearing 1 and the metal strip 19 on the guide bushing 2, the non-rotating ring 6 approaches the guide bushing 2 with an axial movement. Simultaneously, the radial collar 10 of the non-rotating ring 6 comes into contact with the internal front surface of the radial collar 5 and the elastic tabs 20 snap into the shoulder 3a of the tubular part 3 and ensure axial retention of the non-rotating ring 6 with respect to the guide bush 2.

In operation, when a misalignment occurs between the non-rotating ring 6 and the guide bushing 2, the elastic self-aligning member formed by the metal band 19 is deformed, the elastic stress being simultaneously guaranteed by the inflection of the tabs 20 and by the torsion of the transverse bars 25, which guarantees a great flexibility and a good distribution of the stresses. Since the metal strip 19 is made with joint ends to form a ring, the elastic stress is constant whatever the direction of the misalignment.

The embodiments illustrated in figures 8 to 12 retain the same references seen previously for similar elements. In the embodiment illustrated in Figure 8, the metal strip 19 is free of undulations and comprises portions of the strip 23, 24 connected by means of transverse bars 25 which support elastic tabs 20. The strip portion 23 supports a plurality on its outer edge of tabs 27 provided to be bent radially outwards and to contact the radial surface 6a of the end of the non-rotating ring 6 to form a bearing surface which prevents an axial movement of the non-rotating ring 6 with respect to the guide bush 2.

The metal band 19 illustrated in Figures 9 and 13 comprises two rows of tabs 27, 28 bent radially and sheared respectively in the portions of the band 23, 24 which are wider than in the embodiment of Figure 8. The radial tabs 28 which are they extend outwards and are in contact with the cylindrical cavity of the non-rotating ring 6 to achieve a precise centering of the metal strip 19 with respect to the non-rotating ring 6.

The metal strip 19 illustrated in Figures 10 and 14 comprises tabs 29 which are supported by the inner edge of the strip portion 23, i.e., which protrude before folding into a window 26. The tabs 29 are bent radially outward to form some support us as explained above. One of the two cross bars 25 supports an elastic tab 20. The tabs 29 before folding and the elastic tabs 20 alternately project into the windows 26.

The embodiment illustrated in Figure 11 is identical to that illustrated in Figure 10 except that tabs 30, intended to be bent radially outwards, are supported by the inner edge of the strip portion 24 and face the tabs 29. Tabs 30 have the same function as tabs 28 of Figure 9.

The embodiment illustrated in Figure 12 comprises tabs 29, 30 which protrude into the same window 26 in which an elastic tab 20 protrudes. Each transverse bar 25 supports an elastic tab 20 so as to ensure a firmer centering than that provided by the forms implementation of the embodiments of figures 10 and 11.

The clutch thrust bearing illustrated in FIGS. 15 and 17 includes a metal band 19 similar to that of FIG. 10. The band portion 23 extends axially outward in the direction of the clutch diaphragm and rotating ring 11 to form a narrow passage 31 which ensures the tightness of the rolling bearing 1. The narrow passage 31 is formed between the band portion 23 and the free end 13a of the radial portion 13 of the rotating ring 11. The metal band 19 forms a ring and a of its ends 19a (figure 17) overlaps for a small length on the other end 19b. It is also possible to devise to bring the two ends 19a and 19b closer by placing them in contact with each other, ie head to head or at a small distance opposite each other.

Figure 16 illustrates an embodiment identical to that of Figure 15 except that the narrow passage 31 is formed between the belt portion 23 and an annular groove 13b provided on the inner radial surface 13c of the radial portion 13 of the rotating ring 11 The groove 13b can be obtained, for example, by flat molding at the level of the blank of the ring 11 or by reworking the finished ring 11 with chip removal.

Figures 18 to 20 illustrate a different embodiment of the clutch thrust bearing. The rolling bearing 1 comprises an inner rotating ring 11, equipped with a radial part 13 extending radially outwards from the side of the friction diaphragm, and an external non-rotating ring 6, equipped with a radial portion 10 in contact with the collar 5 of the guide bush 2, which extends radially inwards and which supports a cylindrical portion 10a in proximity to the tubular part 3. The metal strip 19 comprises elastic tabs 32 which are punched in the center and along the length of the metal strip 9 and which protrude radially outwards. The windows 26 have small dimensions corresponding to those of the elastic tabs 32. Therefore there is no loss of material during the manufacture of the metal strip 19.

The metal strip 19 is axially housed between the shoulder 3a of the tubular part 3 and the radial collar 5 and is in contact with the external surface 3b of the tubular part 3. The tabs 32 extend radially outwards in the direction of the cylindrical portion 10a of the non-rotating ring 6 which comprises a cylindrical cavity 6b. The cylindrical cavity 6b of the non-rotating ring 6 is provided with a groove 33 the bottom of which is in contact with the elastic tabs 32. The edges 32a of the elastic tabs 32 form bearing surfaces in contact with the edges 33a of the groove 33 and thus axially retain the non-rotating ring 6 with respect to the guide bushing 2. The non-rotating ring 6 is here an outer ring and the rotating ring 11 is an inner ring.

This simplified embodiment is particularly economical while ensuring the self-alignment of the rolling bearing 1 with respect to the guide bush 2 thanks to the radial flexibility of the elastic tabs 32 and the axial retention of the rolling bearing 1 with respect to the guide bush 2 thanks to the contact of the edges 32a of the elastic tabs 32 with the edges 33a of the groove 33 and thanks to the retention of the metal strip 19 by means of the stripping 3a.

The embodiment illustrated in Figure 21 differs from that of Figure 1 in that the metal strip 19, also visible in Figure 22, comprises elastic tabs 34 supported by the inner edge of the strip portion 24, the transverse bars 25 being devoid of of them. The axial retention of the metal strip 19 with respect to the tubular portion 3 is guaranteed by the contact between the end 34a of the elastic tab 34 with the shoulder 3a. This arrangement of the tongues 34 facilitates the assembly of the rolling bearing 1 equipped with the metal band 19 on the guide bushing 2. In fact, during assembly, the elastic tongues 34 are bent radially outwards by the end of the tubular portion 3 then are engage in the shoulder 3a. The corrugations 21, 22 of the metal strip 19 are identical to those of the embodiment of Figure 1.

In the embodiment illustrated in Figure 23, the metal strip 19 has no corrugation but comprises tabs 27, 28 intended to be bent radially outwards to form supporting surfaces which cooperate with the non-rotating ring 6. The tabs 27, 28 are supported respectively on the outer edge of the tape portions 23, 24.

The metal strip 19 of Figure 24 is very close to that of Figure 23 except that the tabs 27, 28, intended to be bent radially outwards, are respectively sheared in the strip portions 23, 24.

The metal band 19 of Figure 25 comprises tabs 29 intended to be bent radially outwards and supported by the inner edge of the portion of the band 23. Each tab 29 protrudes, before its folding, in a window 26 in front of the elastic tab 34.

The metal strip 19 illustrated in Figure 26 is similar to that illustrated in Figure 22 except that a cross bar 25 is disposed between each corrugation 22 and each elastic tab 34.

In the embodiments of Figures 21 to 26, the portion of tape 24 can be elastically deformed by twisting when the elastic tabs 34 flex and thus participate in the elastic self-aligning effort.

The embodiment illustrated in figures 27 to 29 comprises a simplified shaped metal strip 19. The rolling bearing 1 is similar to that of figure 15 except for the fact that the non-rotating ring 6 extends axially towards the rotating ring 11, the radial surface 6a being arranged in proximity to this. The metal strip 19 is axially housed between the shoulder 3a of the tubular portion 3 and the radial collar 5 and is in contact with the outer surface 3b of the tubular portion 3. The metal strip 19 comprises elastic tabs 35 which are axially sheared and which protrude radially outward in the direction of a cylindrical cavity 6c of the non-rotating ring 6 provided with an annular groove 36. The elastic tabs 35 are supported by the inner edge of the belt portion 23 and protrude obliquely not only radially towards the external but also axially in the direction of the radial collar 5. During the assembly of the bearing 1 on the guide bush 2 the elastic tabs 35 are first of all folded by means of the cylindrical cavity 6c of the non-rotating ring 6 then the metal band 19 is engaged in the housing formed by the shoulder 3a and thus ensures the axial retention of the non-rotating ring 6 with respect to the bush guideway 2. The radial end edge 35a of the tabs 35 forms a bearing surface for holding the rolling bearing 1.

In Figure 30 the references of elements similar to those in the previous figures have been increased by the number 100. The clutch thrust bearing comprises a rolling bearing 101 whose rings are fabricated by chip removal with a non-rotating outer ring 106 and a ring rotating internal part 111 able to come into contact with a friction diaphragm not shown thanks to a portion 11a which protrudes axially from the opposite side of the guide bushing 102. The guide bushing 102 comprises, in addition to the first tubular part 103 and the radial collar 105, a second tubular portion 137 which is supported by the outer diameter of the radial collar 105 and which radially surrounds the rolling bearing 101. The self-aligning metal strip 119 is disposed between the second tubular portion 137 and the non-rotating ring 106 The cylindrical cavity of the second tubular portion 137 is provided with an annular groove 137a with di dimensions suitable for receiving the metal strip 119 and to thus ensure axial retention of the metal strip 119. The metal strip 119 is identical to that shown in Figures 28 and 29 but is mounted in the other direction, i.e. the elastic tabs 135 protrude radially towards the inside and are snapped into an annular groove 138 of the non-rotating ring 106. The radial end edge 135a of the tabs 135 forms a support in contact with the edge 138a of the groove 138.

It can therefore be seen that the rolling bearing 101 can self-align with respect to the guide bush thanks to the flexibility of the tabs 135 but cannot move axially away from them thanks to the contact between the supporting edges 135a and the edge 138a of the groove 138.

The clutch thrust bearing according to the invention is particularly economical insofar as it comprises fewer pieces than known thrust bearings. Furthermore, the elastic self-aligning member has a small radial bulk and its self-centering capabilities are stable over time whatever the temperature of use. Finally, it is possible to use a single type of self-aligning elastic member for several types of thrust bearing, only the shearing length of the strips may be different.

Claims (14)

CLAIMS 1. Clutch thrust bearing of the type comprising a rolling bearing (1) fitted with a rotating ring (11) and a non-rotating ring (6) and mounted on a guide bush (2) fitted with a tubular part ( 3) and a radial collar (5) on which the non-rotating ring (6) of the rolling bearing rests, an elastic self-alignment member of the non-rotating ring (6) with respect to the guide bush (2 ) being arranged radially between the non-rotating ring (6) and a tubular part (3) of the guide bush, characterized in that the elastic self-aligning member comprises a metal band (19) whose ends are mutually approached to form a ring, the aforementioned belt being equipped with elastic tabs (20) provided with axial bearing surfaces (20a), which cooperate with retaining surfaces of the guide bush (2), and with axial bearing surfaces (21a) which cooperate with retaining surfaces of the anus llo not rotating (6). 2. Clutch thrust bearing according to claim 1, characterized in that the spring tabs (20) are separated from each other at least by a cross bar (25). Thrust bearing for friction according to claim 1 or 2, characterized in that the tabs (20) are cut in the metal strip (19) in a circular direction and are supported by the cross bars (25). Thrust bearing for friction according to claim 1 or 2, characterized in that the tabs (20) are cut axially in the metal strip (19). Thrust bearing for friction according to any one of the preceding claims, characterized in that the metal band (19) comprises a plurality of corrugations (21, 22) regularly distributed in an annular direction. Thrust bearing for friction according to one of claims 1 to 4, characterized in that the metal band (19) comprises a plurality of radial tabs (27) which form bearing surfaces which cooperate with the non-rotating ring (6) . Clutch thrust bearing according to claim 6, characterized in that the radial tongues (27) are cut on one edge of the metal strip (19). 8. Clutch thrust bearing according to claim 6, characterized in that the radial tabs (27, 28) are cut on both edges of the metal strip (19). 9. Thrust bearing for clutch according to. claim 6, characterized in that the radial tabs (29, 30) are cut in the center of the metal strip (19). Thrust bearing for friction according to claim 9, characterized in that the radial tongues (29, 30) are sheared in proximity to elastic tongues (20). Clutch thrust bearing according to any one of the preceding claims, characterized in that an edge of the metal strip (19) forms a narrow passage (31) with the rotating ring (11) so as to ensure the sealing of the rolling bearing . Thrust bearing for friction according to any one of claims 1 to 5, characterized in that the metal band (19) is arranged between a shoulder (3a) of the tubular part (3) and the collar (4) of the guide bush, the tabs (32) protruding from the japtallic band in the direction of the non-rotating ring (6) and the edges (32a) of the tabs forming support surfaces designed to cooperate with the non-rotating ring. 13. Clutch thrust bearing according to claim 12, characterized in that the non-rotating ring (6) is provided with a groove (33) capable of cooperating with the supporting surfaces of the elastic tabs (32). Friction thrust bearing according to any one of the preceding claims, characterized in that the guide bush (102) comprises a second tubular part (137) which surrounds the non-rotating outer ring of the rolling bearing, the metal band being arranged between the outer surface of the non-rotating ring and the cylindrical cavity of the second tubular part.