FR2736118A1 - SHOCK ABSORBER FLYWHEEL INTENDED TO BE INTERPOSED IN A MOTOR VEHICLE POWERTRAIN, COMPRISING IMPROVED MEANS FOR MOUNTING ITS ROTATION BEARING - Google Patents

Abstract

The invention provides a damping flywheel (10) arranged between two coaxial rotating assemblies (12, 14) in the form of parallel plates (20, 26) one of which (20) has a central hub (18) which passes through the other rotating element (14, 26) with interposition of a bearing (28), of the type in which a friction damping device (58) surrounds a first cylindrical section (114) of larger diameter of the stepped hub (18), which is surrounded by a friction damping device (58), a second section (116) of smaller diameter receiving a ring (100) for axial retention of the damping device (58), characterized in that the hub ( 18) comprises a third section (120) of diameter smaller than that of the second section (116) on which is mounted the inner ring (109) of the bearing which is in axial support against the radial shoulder (122) which delimits between them second (116) and third (120) sections of the stepped hub (18).

Description

The present invention relates to a damping flywheel intended to be arranged

  between two coaxial rotating assemblies, one of which is intended to be connected to the internal combustion engine of a powertrain, in particular of a motor vehicle, and the other of which is intended to be connected to the shaft

  of the transmission of this powertrain.

  The invention relates in particular to a shock absorber of the type described and shown in document FR-A-2,687,442 which comprises first and second coaxial rotating elements in the form of parallel plates, one of which comprises a central hub which passes through the other rotating element with the interposition of a bearing, in particular a bearing, of the type in which a friction damping device with axial action is arranged in the annular space delimited axially by the internal faces opposite rotating elements and

  radially inward through the outer surface of the hub.

  Such a design is also described and represented in document US-A-4,782,933 according to which the hub has a stepped profile, a first section of larger diameter, adjacent to the internal face of the first rotating element, is surrounded by the device. friction damping, a second section of smaller diameter receives an axial retaining ring of an elastic member with axial action of the damping device, and of the type in which the bearing comprises an inner ring mounted on a cylindrical bearing of the hub and in axial support, in the direction of the internal face of the first rotating element, against a radial shoulder. In the design according to document US-A-4,782,933, the inner ring of the bearing forming the bearing and the axial retaining ring are both mounted on the second

section of the stepped hub.

  The axial position of the bearing in relation to the other components therefore depends on a stack of dimensions taking into account

  the axial thickness of the retaining ring.

  According to another design described and shown in French patent application No. 9408257 filed on June 30, 1994, the retaining ring is mounted in an inner radial groove formed in the second section of the stepped hub and, here again the axial position of the bearing depends on position

  axial of the retaining ring relative to the hub.

  The object of the present invention is to propose an improvement to a damping flywheel of the type mentioned above which makes it possible to ensure precise positioning of the bearing with respect to the hub which does not result from a stacking of

  dimensions of different components mounted on the hub.

  To this end, the invention provides a damping flywheel of the type mentioned above, characterized in that the outer cylindrical wall of the hub has a third section, of diameter less than that of the second section, on which is mounted the inner ring of the bearing which is axial support against the radial shoulder which delimits between them the second

  and third sections of the stepped hub.

  According to other characteristics of the invention: - the axial retaining ring bears axially against the radial shoulder which delimits the first and second sections of the stepped hub; - The axial retaining ring is immobilized axially in axial support against the radial shoulder; the axial retaining ring is immobilized axially by crimping; the axial retaining ring is immobilized axially by welding; the axial retaining ring is immobilized axially by a split elastic ring mounted in an internal radial groove formed in the second section of the stepped hub; - The elastic member with axial action of the damping device is an elastic washer; - the axial retaining ring is a flat ring; - The arrangement comprises means for immobilizing the elastic washer in rotation relative to the hub; - The axial retaining ring is immobilized in rotation relative to the hub and the elastic washer is immobilized in rotation relative to the axial retaining ring; the flat axial retaining ring has at least one tab which extends axially from the peripheral edge of the ring and which is received in a complementary notch

  formed in the elastic washer.

  It will be appreciated, thanks to the invention, that the bearing is well prepositioned because it is in axial support against a shoulder of the hub. In addition, the shoulder offered by the hub to the axial retaining ring can be of a good size.

  favorable to good seating of said ring.

  Thanks to the third section, we can reduce the

radial dimension of the bearing.

  Other characteristics and advantages of the invention

  will appear on reading the detailed description which follows

  for the understanding of which reference will be made to the appended drawings in which: - Figure 1 is a view in axial section, along line 1-1 of Figure 2, of an exemplary embodiment of a damping flywheel in accordance with the teachings of the invention; - Figure 2 is a partial right view, partially illustrated in section along line 2-2 of Figure 1, of the damping flywheel illustrated in this figure; - Figure 3 is a view on a very large scale of

detail A of figure 1.

  There is shown in Figures 1 to 3 a damping flywheel 10 which is essentially constituted by a first rotating element 12 and a second rotating element 14, which are capable of rotating relative to each other

around an X-X axis.

  The rotating elements 12, 14 here consist, in a manner known per se, of coaxial masses mounted movable relative to one another against a damping elastic device 32 with circumferential action and

  of a friction damping device 58 with axial action.

  The first rotating element 12, here in the general form of a plate, comprises an outer ring 16 intended to cooperate with a starter of a powertrain (not shown) and a central hub 18, produced in one piece with the plate 12, provided to be fixed on the end of a

  engine crankshaft (not shown).

  The rotating element 12 is, here in moldable material such as cast iron or an aluminum alloy, essentially consisting of a plate 20 and a cylindrical annular peripheral skirt 22 of axial orientation, which partially surrounds a skirt cylindrical peripheral annular 24 which extends axially the main plate-shaped part 26 of the rotating element 14, which is rotatably mounted on the hub 18 by means of a ball bearing 28, or as a variant not represented by a other level for example

a smooth bearing.

  The plates 20 and 26 and the skirts 22 and 24 delimit an annular housing 30 which is designed to receive, according to a known design, the elastic damping device 32 consisting of a set of helical springs, here arranged

in crown.

  The housing 30 is here defined for the most part by the plate 20, the skirt 22, here in one piece with the plate

  20, and a disc 34 of the first rotating element 12.

  At its internal periphery, this housing 30 reveals a slight slot in which an annular disc 42 of the second rotating element 14 penetrates and this with sealing

as described below.

  The first rotating element 12 also comprises the internal radial disc 34 which extends radially inwards from the skirt 22 between the two plates 20 and 26 in the direction of an annular space 36 delimited axially between the portions of internal planar faces in opposite 38 and 40 of

turntables 20 and 26.

  The disc 34 is linked in rotation to the outer skirt 22 by sealed crimping as described and shown in the

document FR-A-2.695.579.

  To do this, the skirt 22 has a groove intended to receive the metal from the metal disc 34, during stamping

of it.

  As a variant, this waterproof attachment can be produced

  by screwing as described in document FR-A-2,687,442.

  Alternatively, riveting or

welding.

  The disc 34 partially defines the housing 30, the plate 26 being hollowed out for the housing of the annular disc 34, which is locally stamped at 80, as can be seen in FIG. 1, for the circumferential support of the springs

of the device 32.

  Opposite these stampings 80, the plate 20 has plates 81 fixed by riveting, as can be seen in the lower part of FIG. 1, which constitute supports

  for the circumferential ends of the springs.

  The second rotating element 14 also carries the annular inner disc 42 which is linked to it in rotation by riveted posts 44, and which extends radially in

  the annular space 36 and in the annular housing 30.

  The second rotating element 14 forms, using its plate 26 and in a manner known per se, the reaction plate

of a clutch.

  Thus, this second element 14 is intended to be locked in rotation on the input shaft of the gearbox (not shown) by means of a clutch friction disc, the friction linings of which are intended to be pinched between the reaction plate 26 and a pressure plate (not shown), belonging to a clutch mechanism intended by its cover to be attached by screws received in tapped holes, one of which is visible to the lower part of Figure 1, formed in the tray

reaction 26.

  The outer edge 46 of the annular disc 42 has outer radial lugs 50 provided to act as stops at the ends of the springs of the elastic device

amortization 32.

  Thus, the springs, bearing on the pads

  and the stamped 82 of the disc 34, for example through the

  of support pads in a manner known per se, are intended to be compressed by the legs 50 penetrating into the

housing 30.

  It will be noted that anti-wear parts 82, here in the form of a chute are interposed radially between the springs 32

and the skirt 22.

  The peripheral part of the disc 42 extends between a portion of internal surface facing 52 of the plate 20 and a portion of internal surface facing 54 of the radial disc

  internal 34 of the rotating element 12.

  Thus, the legs 50 penetrate inside the housing 30, a small gap existing between the plate 20

  and the disc 34 for the penetration of the annular disc 42.

  The internal sealing of the annular housing 30, and its separation from the annular space 36, is ensured by two

  sealing washers 56A and 56B.

  The two washers 56A and 56B are two annular parts made of cut and stamped sheet metal and they therefore close the housing 30 at its internal periphery, this housing being partially filled with grease to lubricate the springs of the

device 32.

  As can be seen in FIG. 1, the external radial edge of the washer 56A cooperates and is in axial elastic support against a bearing surface formed opposite in the plate 20 of the first rotating element 12, while the outer radial edge of the second sealing washer 56B cooperates and is in axial elastic support against a bearing surface formed opposite the disc 34 of the first element

  turning 12, on the inner periphery thereof.

  The washers 56A and 56B are arranged on either side of the disc 42 while being attached to the latter. The washers 56A and 56B are preassembled with the disc 42 by

  non-referenced rivets adjacent to the columns 44.

  The damper flywheel 10 also includes a

  friction damping device 58.

  This device 58 surrounds the hub 18 and it comprises a first part 60 constituted by a ring of friction material which is intended to rub on a portion of the planar internal surface 38 of the plate 20 of the first rotating element 12, and by a second part 62 which is constituted by a washer, here metallic, driven in rotation, possibly after taking up an angular play, by the

second rotating element 14.

  An elastic washer 64, which resiliently urges the washer 62 to bear against the friction ring 60 is also provided. The washer 64 of the Belleville washer type, alternatively a washer of the wavy type, bears axially

  against a ring 100 axially fixed on the hub 18.

  Hub 18 has through holes for screws

  fixing the flywheel to the engine crankshaft.

  Such a screw 92 is illustrated in the central part of

Figure 1.

  Thus, the flywheel is arranged between two rotating assemblies, one of which (the crankshaft) is connected to the internal combustion engine and the other of which is connected to the input shaft.

of the gearbox.

  The ring 60 is fixed to the washer 62 here by gluing. As a variant, the ring 60 is fixed by gluing to the surface 38. As a variant, the ring 60 is free. The ring 60 can thus rub against the washer 62 while being for example

secured to the surface 38.

  Thus the ring 60 is intended to be clamped axially between the washer 62, forming a distribution washer, and the

portion of the surface 38.

  According to a known design, the metal washer 62 has external radial lugs 94 which delimit notches, each of which receives the head of a balonnette 44 for

  the drive in rotation of the washer 62 by the plate 26.

  We will now refer to Figure 3 for the

  detailed description of the design of the hub 18 in accordance with

teachings of the invention.

  As can be seen in Figure 3, the ball bearing 28, interposed between the rotating elements 12 and 14, comprises an outer ring 102 mounted in a housing 104 formed in the internal radial end portion 106 of the plate 26 in the bottom of which it is urged to bear axially against a radial shoulder 108 by lugs 110 which extend radially inwards from the edge

  internal device 112 of the annular disc 42.

  The legs 110 are thinned and an axial clearance exists between the legs 110 and the internal face opposite the plate.

26.

  The internal end of the legs 110 is offset

  axially in the direction of the plate 20 relative to the edge 112.

  According to the teachings of the invention, the hub 18 is a stepped hub whose external cylindrical wall has

  three floors or adjacent sections.

  The first stage 114 extends axially from the internal surface portion 38 of the turntable 20 and is surrounded by the washer made of friction material 60, by the

  distribution washer 62 and by the elastic washer 64.

  The second section 116 of the hub 18, the diameter of which is less than that of the first section 114, is delimited axially relative to the latter by a radial shoulder 118 against which a face 120 of the axial retaining ring 100

is in axial support.

  According to a known technique, the ring 100, here metallic, is immobilized axially bearing against the shoulder 118 by a crimping operation, for example according to the technique described and shown in the document

FR-A-2.655.095.

  Thus the second section has an annular groove at the root of the shoulder 118, said groove being filled with the material of the ring 100 due to the creep caused by the

  crimping leading to a reduction in thickness (Figure 3).

  The stepped hub 18 also includes a third section or stage 120 whose diameter is less than that of the second stage 116 and with respect to which it is delimited by a

radial shoulder 122.

  Note that the shoulder 122 has a radial size

  lower than that of shoulder 118.

  In accordance with the teachings of the invention, the third section 120 constitutes the cylindrical bearing surface for mounting the inner ring 109 of the bearing 28 which bears axially by its axial end face 124 against

the radial shoulder 122.

  The ring 109 is held in axial support by a washer 126 which is mounted clamped axially against the body of the hub by the screws 92 and by prepositioning rivets 128, one of which is illustrated in the central part of FIG. 1. Thus, in accordance with the teachings of the invention, the inner ring 109 of the bearing 28 is positioned axially precisely relative to the hub 18 directly, that is to say without the interposition of other components. By way of variants (not shown), the axial retaining ring 100 of the elastic washer 64 can be fixed to the hub 18 by welding or by a split elastic ring, also called a "circlip", received in a radial groove

  interior formed in the second section 116.

  According to another characteristic of the invention, the axial retaining ring 100 is a flat ring which comprises a series of lugs 125 which extend axially in the direction of the elastic washer 64 from its edge

external device 127.

  Each of the legs 125 is received in a notch or a complementary notch 128 formed opposite in the washer 64 so as to immobilize the washer 64 in rotation relative to the axial retaining ring 100 which is itself immobilized in rotation relative to the hub 18. Each tab 12

  is centered by the third section 114.

  Thanks to the arrangement of a third section of the stepped hub 18, it is possible to assemble the various components of the friction damping device 58 and hold these components in position before mounting the bearing 28, the radial size is reduced thanks

in the third section.

  Due to the precision of the mounting tolerances of the ball bearing 28, it is possible to reduce the axial width of the bearing while ensuring the axial tightening of its

  inner ring 109 by washer 126.

  It will be appreciated that the tabs 110, of reduced thickness to cooperate with the ring 102, favor the reduction of the axial size due to their axial offset with respect to the main part of the disc 42 and their aforementioned reduced thickness. These legs 110 can thus come at most

near the ring 100.

  It will be noted that the face of the disc 42, turned towards the plate 20, is generally in alignment with the faces of the

  102,109 rings with reduction in axial dimensions.

Claims (11)

  1. Damper flywheel (10) arranged between two coaxial rotating assemblies (12, 14), one of which is intended to be connected to the internal combustion engine of a powertrain, in particular of a motor vehicle, and the other of which be connected to the input shaft of the gearbox of this powertrain, of the type comprising a first and second coaxial rotating elements in the form of parallel plates (20, 26), one of which (20) has a central hub (18) which passes through the other rotary element (14, 26) with the interposition of a bearing, in particular a bearing (28), of the type in which an axial action friction damping device (58) is arranged in the annular space (36) delimited axially by the internal faces opposite (38, 40) of the rotating elements (12, 14) and radially inwards by the external cylindrical surface of the hub (18), which has a stepped profile including a first cylindrical section (114) of greater weight nd diameter, adjacent to the internal face (38) of the first element   rotating (12, 20), is surrounded by the damping device   friction weaving (58), a second section (116) of smaller diameter receives an axial retaining ring (100) of an elastic member (64) with axial action of the damping device (58), and of the type in which the bearing (28) has an inner ring (109) mounted on a cylindrical bearing surface of the hub and in axial support, in the direction of the internal face (38) of the first rotating element (12, 20), against a radial shoulder, characterized in that the outer cylindrical wall of the hub (18) has a third section (120), of smaller diameter than that of the second section (116), on which is mounted the inner ring (109) of the bearing which is in axial abutment against the radial shoulder (122) which delimits between them the second (116) and third (120) sections of the stepped hub (18).   2. Flywheel damper according to claim 1, characterized in that the retaining ring (100) is in axial support against the radial shoulder (118) which delimits the first   (114) and second (116) sections of the stepped hub (18).   3. damping flywheel according to claim 2, characterized in that the ring (100) of axial retention is immobilized axially in axial support against said shoulder radial (118).   4. damping flywheel according to claim 3, characterized in that the ring (100) of axial retention is   axially immobilized by crimping.   5. Flywheel damper according to claim 3, characterized in that the axial retaining ring is immobilized axially by welding.   6. damping flywheel according to claim 3, characterized in that the axial retaining ring is immobilized axially by a split elastic ring mounted in an internal radial groove formed in the second section (107) of the hub floor.   7. Damper flywheel according to any one of   previous claims, characterized in that the ring (100) axial retention is flat.   8. Damper flywheel according to any one of   previous claims, characterized in that the member   elastic (64) with axial action of the damping device   (58) is an elastic washer (64).   9. Damper flywheel according to any one of   previous claims, characterized in that it comprises   means for immobilizing the washer in rotation   elastic (64) relative to the hub (18).   10. Flywheel damper according to claim 9, characterized in that the ring (100) of axial retention is immobilized in rotation relative to the hub (18), and in that the elastic washer (64) is immobilized in rotation by   relative to the axial retaining ring (100).   11. damping flywheel according to claim 10 taken in combination with claim 7, characterized in that the flat ring (100) of axial retention comprises at least one tab (125) which extends axially from the peripheral edge (127) of the ring (100) and which is received in a notch   complementary (128) formed in the elastic washer (64).