GB2184203A

GB2184203A - Clutch assembly

Info

Publication number: GB2184203A
Application number: GB08629485A
Authority: GB
Inventors: Matthias Fischer; Rainer Ziss; Peter Wiggen
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Friedrichshafen AG
Priority date: 1985-12-17
Filing date: 1986-12-10
Publication date: 1987-06-17
Anticipated expiration: 2006-12-10
Also published as: FR2601734A1; GB8629485D0; FR2601734B1; DE3544500A1; DE3544500C2; GB2184203B

Abstract

The clutch assembly has a hub (1) on which the friction lining carrier (11) is rotatably mounted through a bearing ring (17) consisting of synthetic plastics material. The bearing ring (17) is secured fast in rotation and radially without play by a plastic deformation in a central opening (15) of a cover disc (7) of a torsional vibration damper of the clutch disc. <IMAGE>

Description

SPECIFICATION Clutch assembly The invention relates to a clutch assemblyfora friction clutch, especially of a motorvehicle.

From Fed. German Insp. Doc. No. 3,306,281 a motorvehicle clutch disc is known in which the cover disc ofthetorsional vibration damper carrying the friction lining carrier of the clutch disc is mounted through a bearing ring on a cylindrical bearing surface ofthe hub of the clutch disc. The bearing ring is a component of a friction device ofthe torsional vibration damper and is loosely installed. The radial playofthebearing ring in relation to the bearing surface of the hub forthe one part and in relation to the central opening ofthe cover disc enclosing itfor the other part determines the radial play of the lining carrier disc in relation to the hub, since the torsional vibration damper is mounted on the hub exclusively through this bearing ring.

Forthe one part the bearing ring must be guided with radial play, even though veryslight, sincethe friction should beslightin orderto improvethe idling behaviour ofthe vibration damper. Moreover radial play must not be too great, since otherwise comparatively great unbalance tolerances occur.

It is an object of the invention to improve the clutch disc ofthe known type so thatthefriction lining carrier can be guided radially on the hub ofthe clutch disc witch very slight tolerances, in a constructionally simple manner.

Within the scope ofthe invention the bearing ring consists of a plastically deformable synthetic plastics material, especially a thermo-plastically deformable synthetic plastics material. In the production ofthe clutch disc the bearing ring is secured by plastic deformation on the disc part ofthe torsional vibration damper which also carries the friction lining carrier. In this operation atthe same time its opening guided radially by the hub is calibrated and centred in relation to the disc part of thetorsional vibration damper with narrow tolerance.

Furthermore in this operation it is ensured that radial play between the bearing ring and the disc part ofthe vibration damper is compensated by plastic deformation of the synthetic plastics material. The central opening ofthe disc part accommodating the bearing ring can therefore be produced with comparatively large tolerances.

lnafirstvariantthebearing ring is manufactured as a separate component from thermo-plastic synthetic plastics material and attached subsequently with plastic deformation to the disc part ofthe vibration damper. The internal diameter of the bearing ring has before assembly a smaller diameter than the associated cylindrical bearing surface ofthe hub. The bearing ring is expanded by meansofthetool mandrel,whereby it is placed against the internal circumference of the central opening ofthe disc part and atthe same time centred.For the axial fixing and securing ofthe bearing ring against rotation, recesses or holes can be provided in the disc part ofthe vibration damper, in which the bearing ring is fixed by plastic deformation.

In a second variantthe tool mandrel intended for the centring and calibration ofthe bearing opening ofthe bearing ring is a component of an injection mould in which the bearing ring is directly injection-moulded to the disc part, with plastic deformation. Here the centring and calibration ofthe bearing ring take place in its production.

The invention permits of balancing out centring defects and tolerances ofthe central opening in the disc part ofthe vibration damper, so that its cover discs do not need to be finely machined but can be stamped out in a simple manner. The calibration can take place very precisely so that the torsional vibration damper has only slight inherent friction and can damp torsional vibrations without delay.

The invention can be utilised in conventional clutch discs of motor vehicles, namely both when the lining carrierdiscis mounted on the hubthrough one ofthe cover discs ofthetorsional vbiration damper and also when the lining carrierdisc is mounted on the hub through a centrally arranged component, similarto a hub disc.

Examples ofembodimentofthe invention will be explained in greaterdetail below by reference to drawings, wherein:- Figure 1 shows an axial longitudinal section through a clutch disc; Figure2 shows an enlarged sectional view of a fitted bearing ring of the clutch disc; Figure 3 shows a sectional view ofthe bearing ring according to Figure 2 beforefitting; Figure 4shows a lateral elevation ofthe fitted bearing ring according to Figure 2; Figure 5shows an enlarged sectional view of a variant of a fitted bearing ring of the clutch disc according to Figure 1; Figure 6shows a plan view of the bearing ring according to FigureS;; Figure 7shows an enlarged sectional view of a further variant of a fitted bearing ring ofthe clutch disc according to Figure 1 and Figure 8shows a plan view of the bearing ring according to Figure 7.

Figure 1 shows the principleofassemblyofa clutch drive assembly for a motor vehicle friction clutch. The clutch disc comprises a hub 1 which is coupled in the usual way fast in rotation with a gear input shaft rotatable about a rotation axis 3. The hub 1 carries a hub dise 5. Cover discs 7, Swhich are firmly connected through spacing rivets 10 into one unit, are arranged axially on both sides of the hub disc 5. The cover disc 7 carries on its external circumference a a lining carrier disc 11 with clutch friction linings 13. A bearing ring 17 of a preferably thermo-plastic synthetic plastics material, explained in greater detail hereinafter, which is secured with plastic deformation on the cover disc 7, is seated radially without play in a central opening 15 ofthe cover disc 7.The bearing ring 17 has a bearing opening 19 with which it is guided radially on a cylindrical bearing surface 21 ofthe hub 1. The cover disc 9 also has a central opening 23, which however isso largethatthe coverdisc7, 9 are guided radially on the hub 1 exclusivelythrough the bearing ring 17.

Helical compression springs 31 ofatorsional vibration damperwhich couple the friction lining carrier disc 11 through the coverdiscs7, 9 and the hub disc5 rotationally elastically with the hub 1 are seated in windows 25 ofthe hub disc 5fortheone part and in axially corresponding windows 27,29 of the cover disc 7,9 for the other part. The torsional vibration dampercomprisesatleastonefriction device 33 with a friction ring 35, a thrust ring 37 guided fast in rotation but axially displaceably on the -coverdisc9 and a dashed spring 39 which clamps in the friction ring 35 between thethrust ring 37 and the hub disc 5.To take up the reaction force of the dished spring 39 the cover disc7 is supported through a radially protruding annularflange 41 ofthe bearing ring 17 ontheflanged disc7.Torsional vibration dampers with friction devices are known. Their assemblyand manner of operation are nottherefore to be explained in greater detail.

Details of several forms of embodiment ofthe bearing ring 17 will be explained hereinafterwith reference to Figures 2 to 8. Parts of like effect are provided with like reference numerals and with a letterfor distinction. For the explanation ofthe clutch disc reference is made to the description of Figure 1.

The bearing ring 17a, represented fitted into the central opening 1 5a of the cover disc 7a in Figures 2 and 4, is represented in Figure3 before fitting as a separate component. As Figure 3 shows, the bearing ring 1 7a consisting of thermoplastic material has a tubular-cylindrical section 43 which carries the annularflange41a on oneaxial end. Before its fitting thetubularcylindrical section 43 has an external surface 45 the diameter ofwhich is smaller than the diameter ofthe opening 1 5a of the cover disc 7a. The tubular cylindrical section 43 further has an internal surface 47 the diameter of which is smaller than the diameter ofthe cylindrical bearing surface 21 ofthe hubl.

For assembly the bearing ring 1 7a is pushed into the opening 1 Se of the cover disc 7a and expanded by means of a slightly conically formed mandrel with simultaneous heating until its external surface45 is seated radially without play in the opening 15a and its internal surface 47 is calibrated with slight tolerance to the diameter of the bearing surface 21 of the hub 1 (Figure 1). The mandrel 49 is here centred in relation to the cover disc 7a so that it leaves behind it in the bearing ring 17a a central bearing opening 1 9a adapted with narrow tolerances to the bearing surface 21.

The axial length ofthe tubularcylindrical section 43 ofthe bearing ring 17a is larger, measured on its outside, than the thickness of the cover disc 7a. The end axially remote from the annularflange 41 a is bent outwards around the edge ofthe opening 1 5a with plastic deformation by means ofthe mandrel 49 for the axial fixing of the bearing ring 17a. Forthe rotation-fast connection ofthe bearing ring 1 7a with the cover disc 7a radial recesses 50 are provided in the circumference ofthe opening 1 5a, into which the synthetic plastics material ofthe bearing ring 17a is pressed radially in the expansion ofthe bearing ring 17a.

The mandrel 49 at the same time expediently forms the heat source forthe heating of the bearing ring 17a. By way of example a heat source in theform of an ultrasonic emitter is suitable.

Figures 5 and 6 show a bearing ring 17bfitted by plastic deformation on a cover disc 7b, which bearing ring differs from the bearing ring 17a according to Figures 2 to 4 essentially only in the nature of its axial fixing on the coverdisc7b.The bearing ring 1 7b consists ofthermo-plasticsynthetic plastics material and has a tubular cylindrical section 51 from which an annularflange 41 b protrudes radially outwards at one axial end. The section 51 passes through the central opening 1 5b of the cover dise 7b whilethe annularflange 41 bflatlyabuttingly overlaps the cover disc 7b.The cover disc 7b contains several holes 53 in distribution in the circumferential direction of the opening 15b, into which holespegs5Sformedontheannularflange 41engage in fitting manner. The pegs 55 are plastically deformed on the side of the cover disc7b oppositeto the annularflange 41 b to form heads 57 which axiallyfixthe bearing ring 17b on the cover disc 7b.

Similarly to the bearing ring 17a the section 51 of the bearing ring 17b has a cylindrical external surface 59 the diameter of which before fitting is slightly smallerthan the diameter of the opening 1 5b, in order to facilitate fitting. The diameter ofthe inner surface ofthe section 51 of the bearing ring 1 7b prefabricated for assembly is of smaller dimensions than the diameter of the associated bearing surface 21 (Figure 1). In assemblythe bearing ring 17b is inserted into the opening 15b and secured axially by deformation ofthe pegs 55 into heads 57.At the sametimeorthereaftera mandrel 61 is introduced centrally in relation to the cover disc 7b into the section 51, and expands the internal surface ofthe section 51 to form a bearing opening 63 which is calibrated and at the same time centred with narrow tolerances according to the diameter ofthe bearing surface 21 (Figure 1). Due to the expansion ofthe section 51 its outer surface 59 places itself against the edge of the opening 1 5b whereby the bearing ring 17b is radially fixed by plastic deformation ofthe section 51. The heating of the bearing ring 17b for its plastic deformation takes place as explained with reference to Figures 2to4.

Figures 7 and 8 show a furthervariant of a bearing ring 17c, which however in distinction from the bearing rings 17a and 17b is not prefabricated and subsequently fitted but directly injection-moulded and centred in calibrated manner on the cover disc 7c in one operation by an injection-moulding method.

The bearing ring 17c, which can likewise consist of thermo-plastic material but can also consist of other material, for example hardening thermo-setting material, has a tubular-cylindrical section 65 adjoined axially on both sides by radially outwardly protruding annularflanges 67,69. One ofthe annular flanges, for example the annularflange 67, here has the function of the annularflange 41 explained with reference to Figure 1. The flanges 67,69 overlap the cover disc 7c. For rotation-fast axial fixing several holes 71 are provided in the cover disc 7c in distribution around the central opening 1 of the cover disc7c,through which holes the annular flanges 67,69 are connected with one another through cast-on crossing pieces 73.

Between the openings 71 and crossing pieces 73 in the circumferential direction the annularflanges 69, 71 contain radial slots 75,77 which lie axially opposite to one another and merge into one another through an axial slot 79 in the tubular cylindrical section 65. The slots 75,77 issue from the inner surfaceofthe bearing ring 1 7e which forms the bearing surface 19b and extend only over a partof the radial height of the annularflanges 67,69. The slots 75,77 and 79 take up thermal expansions in the operation oftheclutch disband reducethe fluctuation ofthefriction between the bearing ring 17e and the bearing surface 21 associated with it (Figure 1) ofthe hub 1.

The bearing ring 17c is directly injection-moulded to the coverdisc7cin an injection mould81.The mould 81, into which the cover disc 7c is inserted in centred manner, contains a mandrel 83 which forms the bearing opening 19b with narrowtolerances and centrally in relation to the cover disc 7c.

Claims

1.) Clutch assemblyforafriction clutch, comprising a) a hub (1 J with a cylindrical bearing surface 21) coaxial with a rotation axis (3), b) a friction lining carrier (11) ofannulardisc form rotatable coaxiallywith the hub (1) and provided with clutch friction linings (13), c) a torsional vibration damper (5,7,9,31,33) having two disc parts (5 and 7,9) rotatable in relation to one another about the rotation axis and rotationally elastically coupled with one another, of which a first disc part (5) is connected with the hub (1 for the torque tra nsmission and of which a second disc part (7,9) has the form of a ring with a central opening (15) in which the cylindrical bearing surface (21) ofthe hub (1) engages and carries the friction lining carrier (11), d) a bearing ring (17) arranged in the opening (15) ofthe second disc part (7,9) by means of which bearing ring the second disc part (7,9) is guided radially on the bearing surface (21), characterised in that the second disc part (7,9) comprises anchoring elements in the region of its central opening (15) and in th at the bearing ring (17) consists of a plastically deformable synthetic plastics material, especially thermo-plastic synthetic plastics material, and is brought by plastic deformation into radially play-free contact with the edge of the central opening (15) and for a rotation-fast connection with the second disc part (7,9) into securing contact with the anchoring elements (49; 53; 71), the plastic deformation being executed while a tool mandrel (49; 61; 83), which has a diameter adapted to the diameter ofthe bearing extension part (21) of the hub (1), is introduced into the bearing ring (17) centrally in relationtothe second disc part (7,9).

2.) Clutch assembly according to Claim 1, characterised in that the bearing ring (17a; 17b) is formed as a component consisting of thermo-plastic synthetic plastics material and independent of the second disc part (7,9), the internal diameter of which componentissmallerthanthediameterofthe bearing surface ofthe hub (1) and which component after heating is expanded by introduction of the tool mandrel (49; 61)tothediameterofthebearing surface (21).

3.) Clutch assembly according to Claim 2, characterised in that the bearing ring (17a) comprises a tubular cylindrical section (43) and a radially protruding annularflange (41 a) at one end of the section (43), the external diameter of the tubular cylindrical section (43) before the plastic deformation ofthe bearing ring (17a) being smaller than the diameter of the opening (1 5a) of the second disc part (7,9) and the axial length ofthetubular cylindrical section (43) being greaterthan the thickness of the second disc part (7,9) in the region of its opening (15a), and in thatthe end ofthetubular cylindrical section (43) axially remote from the annularflange (41 a) being forced radially outwards by plastic deformation for the axial securing ofthe bearing ring (17a).

4.) Clutch assembly according to Claim 3, characterised in that the tool mandrel (49) has a taper form over at least a part of its length.

5.) Clutch assemblyaccording to one of Claims 2 to 4, characterised in thatthe central opening (15a) of the second disc part (7,9) has a configuration differing from the circularform forthe securing of the bearing ring (17a) in rotation.

6.) Clutch assembly according to Claim 2, characterised in that the bearing ring (17b) has a tubular cylindrical section (51) and a radially protruding annularflange (41 b) atone end ofthe section (51), the external diameter ofthetubular cylindrical section (51) before the plastic deformation being smaller than the diameter ofthe central opening (1 5b) ofthe second disc part (7,9), in that the second disc part (7,9) comprises several recesses (53) distributed around the central opening (1 5b) and in that from the annularflange (41 b) there protrude axially pegs (55) which pass through the recesses (53) and are secured on the side ofthe second disc part(7, 9) remotefrom the annular flange (41 b) by plastic deformation.

7.) Clutch assemblyaccordingto Claim 1, characterised in that the bearing ring (17c) is cast directly to the second disc part (7,9) in an injection mould (81) containing the tool mandrel (83).

8.) Clutch assembly according to Claim 7, characterised in that the second disc part (7,9) comprises several holes (71) distributed around the central opening (15c) and in thatannularflanges (67, 69) which are connected with one anotherthrough the holes (71) are castto the bearing ring (17c) on both sides of the second disc part (7,9).

9.) Clutch assembly according to Claim 8, characterised in that the bearing ring (17c) comprises in the annularflanges (67,69) several radial slots (75,77,79) arranged in the circumferential direction between the holes (71), which slots extend, starting from the internal circumference, over only a part ofthe radial height of the annularflanges (67,69).

10.) Methodfortheproduction of a clutch assembly according to one of Claims 1 to 6, characterised in that the bearing ring (17a; 17b) is produced separately, then inserted into the central opening (1 Sal Sb) ofthe second disc part (7,9) and expanded and centred in relation to the second disc part(7,9) by insertion of a tool mandrel (49; 61).

11.) Clutch assembly as claimed in Claim 1 substantially as described with reference to Figures 1-4, Figures 5 and 6, or Figures 7 and 8 ofthe accompanying drawings.