GB2222438A

GB2222438A - Clutch disc with hub lubrication device

Info

Publication number: GB2222438A
Application number: GB8918905A
Authority: GB
Inventors: Hans-Jurgen Drexl; Nikolaus Rudolph; Winfried Sturmer
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1988-08-20
Filing date: 1989-08-18
Publication date: 1990-03-07
Anticipated expiration: 2009-08-18
Also published as: GB8918905D0; GB2222438B; DE3828353A1; DE3828353C2; FR2635567A1; FR2635567B1

Description

Clutch disc with hub lubrication device The invention relates to a clutch

disc for a friction clutch of the pulled construction type with a hub with multi-splined internal profile for fitting fast in rotation on a corresponding counter-profile of a gear shaft which is mounted rotatably together with the clutch disc about a common axis of rotation, in which in releasing the release elements carry out a movement in the direction towards the clutch disc together with the releaser.

A friction clutch of the pulled construction type with a corresponding clutch disc is known for example from DE-PS 1,555,408. This known friction clutch comprises a diaphragm spring which is supported in the region of its external diameter on the clutch cover and in the region of a smaller diameter on the presser plate. Furthermore a releaser device is provided which grasps around the radially inwardly pointing ends of the spring tongues and thus clears the presser plate by a pulling movement in the release operation. In the engagement operation the releaser and the spring tongues of the diaphragm spring move in the direction towards the clutch disc.

In the fitting of the clutch disc on the gear shaft the toothing between the two parts is once provided with a lubricant in order to achieve easy axial displaceability throughout the life. This axial displaceability must be guaranteed in order to avoid separation problems in the uncoupled condition and to act against increased wear of the friction linings. Problems of this kind arise to a special 2r n LA24,78 extent in multi-disc clutches and there especially in the directly charged first clutch disc facing the release system. The reason for this is that this clutch disc has to travel not only its own clearance distance but additionally also that of the second clutch disc.

The quantity of lubricant used in the fitting of the clutch discs must here not exceed a specific amount, in order not to be thrown on to the friction linings during operation. However a frugal application of lubricant in many cases is not adapted to retain its lubricant power over the whole period of life of a friction clutch.

An object of the present invention is to provide a clutch disc assembly in which the lubrication conditions in the engagement toothing between clutch disc and gear shaft are such that satisfactory lubrication is ensured over the whole range of life of the clutch.

According to the invention there is provided a clutch disc assembly for a friction clutch of the pulled construction style having a hub with multispline internal profile for rotation-fast but axially displaceable setting upon a corresponding counter-profile of a gear shaft, which is mounted rotatably together with the clutch disc about a common axis of rotation, in which the release elements in engagement carry out together with the releaser a movement in the direction towards the clutch disc, characterised in that for the automatic relubrication of the interspaces between 1 3 the profiles of hub and gear shaft in the hub a cavity with lubricant reserve is arranged from which at least one connection passage extends to the profiles, while furthermore at least one displacement body is provided which extends parallel with and with spacing from the common axis of rotation, which body extends from the hub in the direction towards the release elements and the end region of which, facing the release elements, in the case of friction lining wear can be loaded by the release elements and/or the releaser when the friction clutch is in the engaged condition and the end region of which, remote from the release elements, opens into a lubricant-filled chamber which is in communication with the cavity.

In connection with a clutch of the pulled construction type an automatic relubrication device is proposed, a cavity with a supply of lubricant being arranged in the hub, which cavity for the one part is connected through at least one connecting passage with the profile, while on the other hand at least one displacement body is provided which is displaceable by the release system in the engagement operation due to the wear on the friction linings - into a chamber which is filled with lubricant and is in communication with the cavity. Due to this device, as the wear of the friction linings of the clutch disc progresses the follow-up of lubricant into the spline region between hub and gear shaft is automatically maintained and thus for the one part a satisfactory axial displaceability of the hub is guaranteed and for the other part the supply of lubricant is metered in such a way that no excess offer occurs.

The cavity may be made as an annular passage extending concentrically with the axis of rotation. Thus it is easily possible to provide each tooth of the internal splining with a connection passage with every connection passage opening in the concentric annular passage. The other end opens in each case in the region of the tooth tip, namely approximately in the middle of the axial extent of the internal splining. Due to this configuration lubricant can be distributed with correct portions uniformly in the entire region of the splining, directly at the sliding points. Due to the fact that opening takes place in each case in the region of the tooth tip it is also ensured that the lubricant is transported radially outwards into the root circle region of the internal splining by centrifugal force.

Furthermore the annular passage is provided with a plurality of cylindrical bores distributed on the circumference, which extend axially and concentrically with the rotation axis and are provided, from the release elements, with axially displaceable pistons. These pistons shift in the cylindrical bores according to the friction lining wear after every clutch engagement action, and force lubricant out of the cylindrical bores by way of the annular passage and each connection passage into the splining. The pistons are here advantageously connected with one another by their end regions facing the release elements of -the clutch, through a common ring.

For easy production and sealing the hub comprises an annular face turned away from the release elements, which face extends perpendicularly of the axis of rotation and is sealed off to the exterior, with for the one part the annular passage and for the other part the cylindrical bores opening into this face and the diameter of the annular passage lying between the diameters including the contours of the cylindrical bores. Thus easy machining of all bores is possible from one side and also an easy sealing to the exterior can be provided on this side.

Here each connection passage - starting from the tip circle - has an acute angle in relation to the axis of rotation and opens in the annular passage, which has a larger diameter than the tip circle.

The hub is advantageously formed so that in the region of its external diameter it has a hub disc which is covered from both axial sides by cover plates of a torsional vibration damper while the annular passage and the cylindrical bores extend in the region of the hub disc and the cover plate remote from the release elements seals off the annular chamber and the bores to the exterior. Due to the connection of the two cover plates with one another - 6 through rivets and the concentric arrangement of two seals the sealing of the cylindrical bores to the exterior is guaranteed in a simple manner. At the same time the arrangement of the rivet bores and also the cylindrical bores can take place circumferentially staggered approximately on the same mean diameter. Here the cover plate facing the release elements is formed with appropriate openings for the passage of the pistons.

Into the cylindrical bores there are inserted cylinder inserts which have a greater axial extent than the bores. Thus - independently of the axial extent of the hub disc, a guide for the pistons lubricant can be arranged.

and a corresponding reserve of The cylinder inserts here penetrate the openings in the cover plate facing the release system and also extend in the direction of the release elements.

The arrangement of the hub with the automatic hub lubrication device preferably takes place in the clutch disc, facing the release levers, of a twodisc clutch.

The invention will next be explained in greater detail by reference to an example of embodiment. In detail Figure 1 shows the longitudinal section through a twodisc clutch; Figures 2 and 3 show an elevation and a section of the hub in enlarged representation.

Figure 1 shows the overall arrangement of an automatic relubrication system in the hub of' a clutch disc, this equipment being of great importance especially for those - 7 clutch discs which are closest to the release elements in two-disc clutches. In general 1 signifies the friction clutch. It consists of a fly-wheel 2 secured to the crankshaft of an internal combustion engine, to which fly-wheel the clutch cover 4 is screwed, an intermediate ring 3 being interposed. In the clutch cover 4 a diaphragm spring 5 is supported in the region of its external circumference and extends radially inwards with its spring tongues 13. At a middle diameter of the diaphragm spring 5 the latter bears on the presser plate 6, this presser plate 6 being connected fast in rotation but axially displaceably in a manner not further illustrated with the clutch cover 4. Radially within the contact between diaphragm spring 5 and presser plate 6 there are provided several circumferentially distributed screws 33 which through springs 34 maintain a lasting contact between diaphragm spring 5 and presser plate 6. This serves especially for secure disengaging of the friction clutch. Between presser plate 6 and fly-wheel 2 there are arranged in axially staggered manner, in sequence, a clutch disc 9, an intermediate plate 7 and a clutch disc 8. The two clutch discs 8 and 9 are arranged fast in rotation but axially displaceably by means of appropriate splines on a gear shaft (not shown). The intermediate plate 7 is likewise mounted through elements (not shown) fast in rotation but axially displaceably in relation to the clutch cover 4 and/or in relation to the intermediate ring 3. The radially inwardly pointing ends of the spring tongues 13 are in an operative connection with the releaser 10, which - 8 comprises a housing 35 on which there is f itted the nonrotating outer race ring 11 of a rolling bearing, while the rotating inner race ring 12 penetrates the opening of the diaphragm spring 5 in the axial direction and grasps from inwards around the spring tongues 13. All the parts of the friction clutch 1 - with the exception of the housing 35 of the releaser 10 and of the outer race ring 11 - rotate in operation about the common rotation axis 30.

The function of the friction clutch will next be discussed briefly. According to the illustration in Figure 1 the clutch is engaged. For disengagement the housing 35 of the releaser 10 is moved together with the outer race ring 11 away from the friction clutch 1 by a release fork (not shown), whereby the spring tongues 13 pivot to the right-and thus the diaphragm spring 5 is brought temporarily into a conical form. In the sectional plane according to Figure 1 thus the diaphragm spring 5 pivots about its tilting circle in the region of its external diameter in such a way that the presser plate 6 is pivoted by the springs 34 likewise to the right into the disengaged position. Thus the two clutch discs 8 and 9 with their friction linings 32 become free from axial force loading and in addition the clutch disc 8 is released by an axial spring system (not shown) of the intermediate plate 7, which likewise is effective to the right. The engagement operation takes place in the converse direction. The clutch disc 9 arranged closer to the release elements must here travel an especially long release distance and this - 9 necessitates an axial displacement of the entire clutch disc 9 on the gear shaft. This axial displacement must also be able to take place in the case of a partial loading of the friction linings 32 by an axial force, where a certain torque must already be transmitted by the clutch discs. In order to achieve a satisfactory displacement primarily of the clutch disc 9, over the whole life of the friction clutch, its hub 14 is provided with an automatic relubrication device. This device will be described in greater detail below in connection with Figures 2 and 3.

Figure 3 shows the view of the hub 14 of the clutch disc 9 and Figure 2 shows the section II - II. The hub 14 is provided in the usual way with a radially protruding hub disc 15 which comprises two parallel faces 36 and 37 extending perpendicularly of the common axis 30 of rotation. The two cover plates 26 and 27 of a torsional vibration damper 38 are laid on these faces according to Figure 1. The function can admittedly be realised even without a torsional vibration damper, in which case then only a cover plate 26 is necessary for sealing. In the hub 14 there are arranged several circumferentially distributed cylindrical bores 217 the axes of which extend parallel and concentrically with the rotation axis 30. Into these bores there are inserted cylinder inserts 22 which are made longer in the axial direction then the bores 21 and protrude in the direction towards the release system 10. Moreover an annular passage 20 is so arranged in the face 36 of the hub disc 15 that on the one hand it is made open into the face 36 and on the other hand it has a mean diameter which connects the faces of all chambers 31 formed by the cylinder inserts 22. The rivet bores 23 for the cover plates 26 and 27 are arranged on the same mean diameter - staggered in the circumferential direction. Now from the annular passage 20 in each case connection passages 19 go through the hub in the direction of the internal splining 16-, namely in such manner that according to Figure 3 a connection passage 19 opens in the region of each tooth tip 18. Thus each tooth 17 of the internal splining 16 is connected through a connection passage 19 in each case with the annular passage 20 and thus also with the chambers 31. Furthermore the hub disc 15 is provided on the face 36 with two sealing rings 24 and 25, the sealing ring 24 hav ing a diameter which is somewhat larger than a circular connection line enveloping all cylindrical bores 21 to the exterior. The sealing ring 25 has a diameter which is smaller than a circular connection line enveloping all the bores 21 to the interior. Thus after the setting on of the cover plate 26 and the riveting it is ensured that all cavities arranged in the hub 14 - pointing away in the axial direction from the releaser 10 - are sealed. The chambers 31 are provided according to Figure 1 each with a cylindrical piston and each piston 39 is made axially displaceable and made sealed in relation to the internal diameter of the corresponding cylinder insert 22. All the pistons are firmly connected with one another through a ring 29. It is also to be pointed out that all connection passages 19 have an acute angle in relation to - 11 the rotation axis 30 and their ends towards the splining are situated approximately in the middle of the axial extent of the hub 14.

Now the function is as follows Before the assembly of the clutch disc 9 all cavities in the hub 14 - the chambers 31, the annular passage 20, the connection passages 19 - are filled with -lubricant and the pistons 39 are inserted from the side of the releaser 10 into the cylinder inserts 22. Af ter the fitting of the clutch disc 9 parts of the releaser 10, in the engaged condition according to Figure 1, are situated directly on the ring 29. With increasing use of the friction clutch I and with the gradually occurring wear on the friction linings 32, the releaser 10 after each actuation travels a small. amount in the direction towards the clutch disc 9, since wear on the friction linings 32 permits the presser plate 6 likewise to travel to the left in the direction towards the clutch disc 9, whereby the diaphragm spring 5 likewise completes this movement into the spring tongues 13. Each approach of the releaser 10 in the direction towards the clutch disc 9 has the effect that the pistons 39 are axially displaced and forced into the chambers 31. There each time they expel a partial quantity of the lubricant which can escape only by way of the annular passage 20 and the connection passages 19 in the direction towards the splining. Since the individual connection passages 19 end each in the tip region of the teeth 17, here the issuing lubricant is transported by centrifugal force along the - 12 tooth flanks into the root circle of the internal splining 16. Thus it ensures a constantly easy axial mobility of the hub in relation to the gear shaf t and thus a satisfactory function of the friction clutch, while especially the release behaviour and low wear of the friction linings are ensured.

The arrangement as described is naturally also usable in single-disc clutches and is not limited to those clutch discs which comprise a torsional vibration damper. Likewise the application of such a design does not remain limited to releaser systems which are equipped with diaphragm springs, but it is also readily possible to provide lever devices, in which case the presser plate is loaded for example by way of helical springs.

Claims

CLAIMS:

1 - Clutch disc assembly for a friction clutch of the pulled construction style having a hub with multi-spline internal profile for rotation-fast but axially displaceable setting upon a corresponding counter-profile of a gear shaftg which is mounted rotatably together with the clutch disc about a common axis of rotation, in which the release elements in engagement carry out together with the releaser a movement in the direction towards the clutch disc, characterised in that for the automatic relubrication of the interspaces between the profiles (16) of hub (14) and gear shaft in the hub a cavity (20) with lubricant reserve is arranged from which at least one connection passage (19) extends to the profiles (16), while furthermore at least one displacement body (39) is provided which extends parallel with and with spacing from the common axis of rotation (30), which body extends from the hub (14) in the direction towards the release elements (10, 13) and the end region of which, facing the release elements, in the case of friction lining wear can be loaded by the release elements (13) and/or the releaser (10) when the friction clutch (1) is in the engaged condition and the end region of which, remote from the release elements, opens into a lubricantfilled chamber (31) which is in communication with the cavity (20).

2. Clutch disc a=wbly according to Claim 1, characterised in that the cavity is made as an annular passage (20) extending concentrically with the rotation axis (30).

3. Clutch disc assembly according to Claims 1 and 2, - 14 characterised in that several circumferentially distributed connection passages (19) are provided.

4. Clutch di-se assembly according to Clairn 1 to 3, characterised in that each connection passage (19) ends in the region of the tooth tip (18) of the corresponding tooth (17) of the internal splining (16) of the hub (14).

5. Clutch disc assembly according to Claims 1 to 5, characterised in that each connection passage (19) ends approximately in the middle of the axial extent of the internal splining (16).

6. Clutch disc assembly according to Claims 1 to 3, characterised in that a connection passage (19) opens into each tooth (17) of the internal splining (16).

7. Clutch disc assembly according to Claim 2, characterised in that the annular passage (20) is provided with a plurality of circumferentially distributed cylindrical bores (21) which extend axially and concentrically with the rotation axis (30) and are provided, from the release elements (5, 10), with axially displaceable pistons (39).

8. Clutch disc assembly according to Claim 17, characterised in that all pistons (39) are connected with one another by their end zones facing the release elements (10, 13) through one common ring (29).

9. Clutch disc assembly according to Claim 8, characterised in that the hub (14) comprises an annular face (36) turned away from the release elements (10, 13), which extends perpendicularly of the rotation axis (30) and is sealed off to the exterior, while for the one part the annular passage - 15 (20) and for another part the cylindrical bores (21) open into this face (36) and the diameter of the annular passage (20) lies between the diameters enclosing the contours of the cylindrical bores (21).

10. Clutch disc assembly according to Claim 9, characterised in that each connecting passage (19) - starting from the tip circle - forms an acute angle in relation to the rotation axis (30) and opens in the annular passage (20), which has a larger diameter than the tip circle.

11. Clutch disc assembly according to Claims 1 to 10, characterised in that the hub (14) comprises in the region of its external diameter a hub disc (15) which is covered from both axial sides (36, 37) by cover plates (26, 27) of a torsional vibration damper (38), while the annular passage (20) and the cylindrical bores (21) extend in the region of the hub disc and the cover plate (26) turned away from the releaser elements (10, 13) seals off the annular chamber (20) and the bores (21) to the exterior.

12. Clutch disc assembly according to Claim 11, characterised in that the two cover plates (26, 27) are connected firmly through rivets with the hub disc, while the bores (21) are arranged approximately on the same middle diameter with angular off-setting in relation to the rivet bores (23).

13. Clutch disc assembly according to Claim 12, characterised in that two concentric seals (24, 25) are arranged between hub disc (14) and turned-away cover plate (26).

14. Clutch disc assembly according to Claim 13, characterised in that the cover plate (27) facing the release elements - 16 (101 13) is provided with corresponding openings for the passage of the pistons (39).

15. Clutch disc assembly according to Claim 14, characterised in that cylinder inserts (22) having a greater axial extent than the bores (21) are inserted into the cylindrical bores (21).

16. Clutch disc assembly according to Clai 1 to 15, characterised in that the clutch disc (9) is preferably the clutch disc facing the release elements (10, 13), of a twodisc clutch

17. Clutch disc assembly substantially as described with reference to the accompanying drawings.

Published 1990 atThe Patent office, State House, 66. 7 L HighHo3burn. London WMR4TP-Purthercoples maybe ObtainedlMmThe P&tG'tOJ1'oe Sales Branch, St Mary Cray, Orpington. Kmt BIR5 3RD. Printed by MultipIex tecbniques Itd. St MW7 CrAY, Kent- Con- 1!87